Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 61
Filtrar
1.
Phys Rev Lett ; 130(21): 212701, 2023 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-37295108

RESUMEN

The rate of the final step in the astrophysical αp process, the ^{34}Ar(α,p)^{37}K reaction, suffers from large uncertainties due to a lack of experimental data, despite having a considerable impact on the observable light curves of x-ray bursts and the composition of the ashes of hydrogen and helium burning on accreting neutron stars. We present the first direct measurement constraining the ^{34}Ar(α,p)^{37}K reaction cross section, using the Jet Experiments in Nuclear Structure and Astrophysics gas jet target. The combined cross section for the ^{34}Ar,Cl(α,p)^{37}K,Ar reaction is found to agree well with Hauser-Feshbach predictions. The ^{34}Ar(α,2p)^{36}Ar cross section, which can be exclusively attributed to the ^{34}Ar beam component, also agrees to within the typical uncertainties quoted for statistical models. This indicates the applicability of the statistical model for predicting astrophysical (α,p) reaction rates in this part of the αp process, in contrast to earlier findings from indirect reaction studies indicating orders-of-magnitude discrepancies. This removes a significant uncertainty in models of hydrogen and helium burning on accreting neutron stars.


Asunto(s)
Helio , Hidrógeno , Modelos Estadísticos , Neutrones
2.
Phys Rev Lett ; 125(6): 062501, 2020 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-32845657

RESUMEN

Precise antineutrino measurements are very sensitive to proper background characterization. We present an improved measurement of the ^{13}C(α,n)^{16}O reaction cross section which constitutes significant background for large ν[over ¯] detectors. We greatly improve the precision and accuracy by utilizing a setup that is sensitive to the neutron energies while making measurements of the excited state transitions via secondary γ-ray detection. Our results shows a 54% reduction in the background contributions from the ^{16}O(3^{-},6.13 MeV) state used in the KamLAND analysis.

3.
PLoS One ; 14(3): e0214021, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30897175

RESUMEN

Greater rates of genetic gain can be achieved by selecting animals born to younger parents. However, little is known about the lifetime performance of dual purpose ewes (Ovis aries) that are born to primiparous ewe lambs (8 to 9 months old at breeding). This experiment investigated the effect of being born from either a ewe lamb or mixed age dam as either a single or twin on the lifetime performance of ewe progeny. Lifetime performance was measured in terms of the life time live weights of the ewes, the weight and number of lambs born and weaned, the efficiency of production (kilograms of lamb weaned / predicted pasture intake (kgDM) of the ewes), and ewe survival. The study followed the lifetime production of 17 single and 41 twin female lambs born to mature ewes (M1 and M2, respectively), and 28 single and 29 twin lambs born to ewe lambs (L1 and L2, respectively). Over their lifetime L2 ewes were lighter (P<0.05) but had similar body condition scores to the other three ewe groups. There was no difference in average progeny weaning weight or total progeny litter weaning weights between groups. The M1 ewes had the greatest longevity (P<0.05) of the four groups. Even though L2 ewes were lighter than the other three groups, this was insufficient to increase their lifetime efficiency of production (kg lamb weaned/predicted pasture consumption), relative to the other groups. These results suggest farmers could select replacements born to ewe lambs without sacrificing animal production.


Asunto(s)
Selección Artificial , Oveja Doméstica/fisiología , Animales , Animales Recién Nacidos , Peso al Nacer , Peso Corporal , Femenino , Tamaño de la Camada , Longevidad , Edad Materna , Nueva Zelanda , Paridad , Embarazo , Oveja Doméstica/anatomía & histología , Oveja Doméstica/crecimiento & desarrollo
4.
Phys Rev Lett ; 122(5): 052502, 2019 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-30822004

RESUMEN

The neutron-capture reaction plays a critical role in the synthesis of the elements in stars and is important for societal applications including nuclear power generation and stockpile-stewardship science. However, it is difficult-if not impossible-to directly measure neutron capture cross sections for the exotic, short-lived nuclei that participate in these processes. In this Letter we demonstrate a new technique which can be used to indirectly determine neutron-capture cross sections for exotic systems. This technique makes use of the (d,p) transfer reaction, which has long been used as a tool to study the structure of nuclei. Recent advances in reaction theory, together with data collected using this reaction, enable the determination of neutron-capture cross sections for short-lived nuclei. A benchmark study of the ^{95}Mo(d,p) reaction is presented, which illustrates the approach and provides guidance for future applications of the method with short-lived isotopes produced at rare isotope accelerators.

5.
Phys Rev Lett ; 122(5): 052701, 2019 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-30822026

RESUMEN

Detection of nuclear-decay γ rays provides a sensitive thermometer of nova nucleosynthesis. The most intense γ-ray flux is thought to be annihilation radiation from the ß^{+} decay of ^{18}F, which is destroyed prior to decay by the ^{18}F(p,α)^{15}O reaction. Estimates of ^{18}F production had been uncertain, however, because key near-threshold levels in the compound nucleus, ^{19}Ne, had yet to be identified. We report the first measurement of the ^{19}F(^{3}He,tγ)^{19}Ne reaction, in which the placement of two long-sought 3/2^{+} levels is suggested via triton-γ-γ coincidences. The precise determination of their resonance energies reduces the upper limit of the rate by a factor of 1.5-17 at nova temperatures and reduces the average uncertainty on the nova detection probability by a factor of 2.1.

6.
Clin Radiol ; 73(8): 682-692, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-29773220

RESUMEN

Needle core biopsy is considered the histological diagnostic method of choice for screen-detected breast lesions. Although the majority are definitively diagnosed as normal, benign, or malignant, approximately 7% are categorised as B3, of uncertain malignant potential. These include a wide range of lesions with different risks of associated malignancy from <2% to approaching 40% from literature review in UK practice. Historically, these have typically been surgically excised as a diagnostic procedure but the majority are then proven to be benign. An alternative approach, for many of these lesions, is thorough sampling/excision by vacuum-assisted biopsy techniques to exclude the presence of co-existing carcinoma. This would potentially reduce the benign open biopsy rate whilst maintaining accuracy of cancer diagnosis. A group from the Radiology, Surgery, and Pathology NHS Breast Screening Programme Co-ordinating Committees and an additional co-opted expert were charged with review and development of guidelines for the clinical management of B3 lesions. The guidelines reflect suggested practice as stated by the NHS Breast Screening Programme and approved by the Royal College of Radiologists.


Asunto(s)
Biopsia con Aguja Gruesa , Neoplasias de la Mama/patología , Tamizaje Masivo , Neoplasias de la Mama/diagnóstico por imagen , Diagnóstico Diferencial , Detección Precoz del Cáncer , Femenino , Humanos , Clasificación del Tumor , Valor Predictivo de las Pruebas , Medicina Estatal , Reino Unido
7.
Animal ; 11(6): 1027-1035, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27869057

RESUMEN

The foetal mammary gland is sensitive to maternal weight and nutrition during gestation, which could affect offspring milk production. It has previously been shown that ewes born to dams offered maintenance nutrition during pregnancy (day 21 to 140 of gestation) produced greater milk, lactose and CP yields in their first lactation when compared with ewes born to dams offered ad libitum nutrition. In addition, ewes born to heavier dams produced greater milk and lactose yields when compared with ewes born to lighter dams. The objective of this study was to analyse and compare the 5-year lactation performance of the previously mentioned ewes, born to heavy or light dams that were offered maintenance or ad libitum pregnancy nutrition. Ewes were milked once per week, for the first 6 weeks of their lactation, for 5 years. Using milk yield and composition data, accumulated yields were calculated over a 42-day period for each year for milk, milk fat, CP, true protein, casein and lactose using a Legendre orthogonal polynomial model. Over the 5-year period, ewes born to heavy dams produced greater average milk (P=0.04), lactose (P=0.01) and CP (P=0.04) yields than offspring born to light dams. In contrast, over the 5-year period dam nutrition during pregnancy did not affect average (P>0.05) offspring milk yields or composition, but did increase milk and lactose accumulated yield (P=0.03 and 0.01, respectively) in the first lactation. These results indicate that maternal gestational nutrition appears to only affect the first lactational performance of ewe offspring. Neither dam nutrition nor size affected grand-offspring live weight gain to, or live weight at weaning (P>0.05). Combined these data indicate that under the conditions of the present study, manipulating dam weight or nutrition in pregnancy can have some effects of offspring lactational performance, however, these effects are not large enough to alter grand-offspring growth to weaning. Therefore, such manipulations are not a viable management tool for farmers to influence lamb growth to weaning.


Asunto(s)
Fenómenos Fisiológicos Nutricionales de los Animales , Leche/metabolismo , Fenómenos Fisiologicos de la Nutrición Prenatal , Ovinos/fisiología , Animales , Peso Corporal , Femenino , Lactancia , Glándulas Mamarias Animales/fisiología , Parto , Embarazo , Ovinos/crecimiento & desarrollo , Destete , Aumento de Peso
8.
Anim Reprod Sci ; 174: 87-92, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27645124

RESUMEN

Excessive mobilization of body reserves during lactation delays the return to reproductive function in weaned primiparous sows. This study tested the hypothesis that supplementing the lactation diets of first-parity sows with ractopamine hydrochloride would reduce maternal weight loss and improve subsequent reproductive performance. Gestating gilts were allocated to one of two treatment groups (n=30 sows/treatment), with one group fed a standard lactation diet (2.5g/Mcal LYS: DE) throughout lactation (CTRL), whereas the treatment group received the standard lactation diet supplemented with 10mg/kg ractopamine hydrochloride (RAC) from d 1 to 13 of lactation and 20mg/kg RAC from d 14 of lactation until artificial insemination (AI). Weaning occurred on d 21 of lactation, with AI occurring at the first post-weaning estrus. Compared to CTRL, RAC supplementation decreased (P<0.05) liveweight loss between d 13 and 20 of lactation (4.3±0.90 versus 1.3±0.96kg), and tended to increase (P=0.06) the number of second litter piglets born alive (9.5±0.52 versus 8.1±0.74). Treatment (RAC versus CTRL) reduced milk protein levels on d 13 and 20 of lactation (P<0.05), and piglet weight gain between d 13 and 20 of lactation (260±0.01 versus 310±0.01g/day, P<0.01). In conclusion, it is evident that dietary RAC altered milk composition and stimulated conservation of maternal body reserves during the third week of lactation, resulting in a beneficial effect on subsequent reproductive performance.


Asunto(s)
Alimentación Animal/análisis , Lactancia/efectos de los fármacos , Leche/química , Fenetilaminas/farmacología , Preñez , Porcinos/crecimiento & desarrollo , Administración Oral , Animales , Composición Corporal , Peso Corporal , Dieta/veterinaria , Femenino , Lactancia/fisiología , Fenetilaminas/administración & dosificación , Embarazo , Preñez/efectos de los fármacos , Porcinos/fisiología
9.
Theriogenology ; 86(6): 1557-1565, 2016 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-27325575

RESUMEN

The objective of this study was to investigate the gene expression of progesterone and estrogen receptor α (PR, ERα), insulin-like growth factor (IGF) 1, IGF-2, their receptor (IGFR1), IGF-binding proteins (BP) 1 to 6, insulin receptor, adiponectin receptors (AdipoR1/2), cyclooxygenase 2 (PTGS2), mucin 1 and to localize PR, ERα, IGF-1, IGFR1, PTGS2, and proliferating cellular nuclear antigen (PCNA) in the endometrium of pregnant (Day 19) Suffolk and Cheviot ewes carrying Suffolk and Cheviot embryos transferred within and reciprocally between breeds. Gene expression was determined by real-time quantitative polymerase chain reaction (RT-qPCR), and antigen determination was measured by immunohistochemistry in the luminal epithelium (LE), superficial and deep glands (SG, DG, respectively) and superficial and deep stroma. Gene expression of PR, IGF-1, IGFBP2, and IGFBP5 was higher in Suffolk than that in Cheviot ewes (P < 0.05). Greater abundance of IGF-2 and IGBP3 expression was found in Cheviot ewes carrying Cheviot embryos than Cheviot ewes carrying Suffolk embryos (P < 0.05). No staining for PR and ERα was observed in the LE, very scarce staining in SG and DG, whereas positive staining was observed in both superficial and deep stroma. No differences were found for PR staining, but Cheviot ewes had higher ERα staining intensity than Suffolk ewes (P < 0.05). Positive staining for IGF-1 was observed in all cell types except DG, and staining of IGFR1 was observed in all cell types. No differences among groups in staining were found for IGF-1 or IGFR1 in any cell type. Positive staining of PTGS2 was observed in LE and SG in all groups. An interaction between ewe and embryo breed affected PTGS2 staining (P < 0.05), whereby Cheviot ewes carrying Suffolk embryos had a lower PTGS2 staining than Suffolk ewes carrying Suffolk embryos. Positive staining of PCNA was found in LE and SG. Suffolk ewes carrying Suffolk embryos showed lower PCNA immunostaining than Cheviot ewes carrying Suffolk embryos (P < 0.05), whereas no differences were observed in ewes carrying Cheviot embryos. This study showed that gestation-related protein expression in the endometrium of Suffolk and Cheviot ewes is affected by both ewe and embryo breed at Day 19 of pregnancy.


Asunto(s)
Transferencia de Embrión/veterinaria , Endometrio/química , Endometrio/metabolismo , Expresión Génica , Ovinos/genética , Animales , Ciclooxigenasa 2/análisis , Ciclooxigenasa 2/genética , Desarrollo Embrionario/genética , Receptor alfa de Estrógeno/análisis , Receptor alfa de Estrógeno/genética , Femenino , Edad Gestacional , Inmunohistoquímica , Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/genética , Factor I del Crecimiento Similar a la Insulina/análisis , Factor II del Crecimiento Similar a la Insulina/genética , Mucina-1/genética , Embarazo , Antígeno Nuclear de Célula en Proliferación/análisis , Receptor IGF Tipo 1/análisis , Receptor IGF Tipo 1/genética , Receptor de Insulina/genética , Receptores de Adiponectina/genética , Receptores de Progesterona/análisis , Receptores de Progesterona/genética , Especificidad de la Especie
10.
Animal ; 10(10): 1655-9, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26997172

RESUMEN

A high proportion of piglets fail to adapt to the changing composition of their diet at weaning, resulting in weight loss and increased susceptibility to pathogens. Polyamines are present in sow milk and promote neonatal maturation of the gut. We hypothesised that oral spermine and spermidine supplementation before weaning would increase piglet growth and promote gastrointestinal development at weaning. In Experiment One, one pair of liveweight (LW)-matched piglets per litter from first and third lactation sows received 2 ml of a 0 (Control) or 463 nmol/ml spermine solution at 14, 16, 18, 20 and 22 days of age (n=6 piglets/treatment per parity). Villus height and crypt depth in the duodenum and jejunum were measured at weaning (day 23 postpartum). In Experiment Two, piglets suckling 18 first and 18 third lactation sows were used. Within each litter, piglets received 2 ml of either water (Control), 463 nmol/ml spermine solution or 2013 nmol/ml spermidine solution at 14, 16, 18, 22 and 24 days of age (n=54 piglets/treatment per sow parity). Piglets were weighed individually at 14, 18, 24 (weaning) and 61 days of age. In Experiment One, oral spermine supplementation resulted in a 41% increase in villus height, a 21% decrease in crypt depth and 79% decrease in the villus height : crypt depth ratio compared with control piglets (P<0.01). In Experiment Two, spermine and spermidine-supplemented piglets suckling first lactation sows grew faster (P<0.05) between days 14 and 18 postpartum than control piglets: 0.230±0.011 and 0.227±0.012 v. 0.183±0.012 kg/day, respectively. Spermine supplementation tended (P<0.1) to increase piglet LW gain from weaning to day 37 post-weaning compared with control piglets (0.373±0.009 v. 0.341±0.010 kg/day). In conclusion, spermine supplementation increased villus height at weaning, and appears to have the potential to improve the pre- and post-weaning growth of conventionally weaned piglets.


Asunto(s)
Dieta/veterinaria , Suplementos Dietéticos , Mucosa Intestinal/anatomía & histología , Mucosa Intestinal/efectos de los fármacos , Poliaminas/administración & dosificación , Poliaminas/farmacología , Porcinos/crecimiento & desarrollo , Administración Oral , Animales , Peso Corporal/efectos de los fármacos , Duodeno/anatomía & histología , Duodeno/efectos de los fármacos , Femenino , Yeyuno/anatomía & histología , Yeyuno/efectos de los fármacos , Masculino , Leche/química , Destete
11.
Phys Rev Lett ; 116(10): 102502, 2016 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-27015475

RESUMEN

The thermonuclear ^{30}P(p,γ)^{31}S reaction rate is critical for modeling the final elemental and isotopic abundances of ONe nova nucleosynthesis, which affect the calibration of proposed nova thermometers and the identification of presolar nova grains, respectively. Unfortunately, the rate of this reaction is essentially unconstrained experimentally, because the strengths of key ^{31}S proton capture resonance states are not known, largely due to uncertainties in their spins and parities. Using the ß decay of ^{31}Cl, we have observed the ß-delayed γ decay of a ^{31}S state at E_{x}=6390.2(7) keV, with a ^{30}P(p,γ)^{31}S resonance energy of E_{r}=259.3(8) keV, in the middle of the ^{30}P(p,γ)^{31}S Gamow window for peak nova temperatures. This state exhibits isospin mixing with the nearby isobaric analog state at E_{x}=6279.0(6) keV, giving it an unambiguous spin and parity of 3/2^{+} and making it an important l=0 resonance for proton capture on ^{30}P.

12.
Phys Rev Lett ; 114(21): 212501, 2015 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-26066430

RESUMEN

The Galactic 1.809-MeV γ-ray signature from the ß decay of ^{26g}Al is a dominant target of γ-ray astronomy, of which a significant component is understood to originate from massive stars. The ^{26g}Al(p,γ)^{27}Si reaction is a major destruction pathway for ^{26g}Al at stellar temperatures, but the reaction rate is poorly constrained due to uncertainties in the strengths of low-lying resonances in ^{27}Si. The ^{26g}Al(d,p)^{27}Al reaction has been employed in inverse kinematics to determine the spectroscopic factors, and hence resonance strengths, of proton resonances in ^{27}Si via mirror symmetry. The strength of the 127-keV resonance is found to be a factor of 4 higher than the previously adopted upper limit, and the upper limit for the 68-keV resonance has been reduced by an order of magnitude, considerably constraining the ^{26g}Al destruction rate at stellar temperatures.

13.
Br J Cancer ; 112(4): 650-9, 2015 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-25625276

RESUMEN

BACKGROUND: Heat-shock protein 990 (HSP990) is a potent and selective synthetic small-molecule HSP90 inhibitor. The primary objectives of this phase I first-in-human study were to determine dose-limiting toxicities (DLTs), maximum-tolerated dose (MTD) and recommended phase II dose (RP2D). Secondary objectives included characterisation of the safety profile, pharmacokinetics (PKs) and pharmacodynamics (PDs). METHODS: Heat-shock protein 990 was administered orally once or two times weekly on a 28-day cycle schedule in patients with advanced solid tumours. Dose escalation was guided by a Bayesian logistic regression model with overdose control. RESULTS: A total of 64 patients were enrolled. Fifty-three patients received HSP990 once weekly at 2.5, 5, 10, 20, 30, 50 or 60 mg, whereas 11 patients received HSP990 two times weekly at 25 mg. Median duration of exposure was 8 weeks (range 1-116 weeks) and 12 patients remained on treatment for >16 weeks. Dose-limiting toxicities occurred in seven patients and included diarrhoea, QTc prolongation, ALT/AST elevations and central neurological toxicities. The most common drug-related adverse events were diarrhoea, fatigue and decreased appetite. Further dose escalation beyond 60 mg once weekly was not possible owing to neurological toxicity. Rapid absorption, no drug accumulation and large interpatient variability in PK exposures were observed. No objective responses were seen; 25 patients had a best overall response of stable disease. CONCLUSIONS: Heat-shock protein 990 is relatively well tolerated, with neurological toxicity being the most relevant DLT. The single agent MTD/RP2D of HSP990 was declared at 50 mg once weekly.


Asunto(s)
Antineoplásicos/administración & dosificación , Proteínas de Choque Térmico Pequeñas/administración & dosificación , Neoplasias/tratamiento farmacológico , Piridonas/administración & dosificación , Pirimidinas/administración & dosificación , Administración Oral , Adulto , Anciano , Antineoplásicos/efectos adversos , Antineoplásicos/farmacocinética , Progresión de la Enfermedad , Relación Dosis-Respuesta a Droga , Femenino , Proteínas HSP90 de Choque Térmico/antagonistas & inhibidores , Proteínas de Choque Térmico Pequeñas/efectos adversos , Proteínas de Choque Térmico Pequeñas/farmacocinética , Humanos , Masculino , Dosis Máxima Tolerada , Persona de Mediana Edad , Neoplasias/patología , Piridonas/efectos adversos , Piridonas/farmacocinética , Pirimidinas/efectos adversos , Pirimidinas/farmacocinética , Resultado del Tratamiento
14.
Domest Anim Endocrinol ; 50: 50-4, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25254312

RESUMEN

Embryo transfer of large sheep breed embryos (Suffolk) into small breed ewes (Cheviot) constrains birth size, but the maternal factors influencing fetal growth restriction are unknown. We hypothesized that reciprocal embryo transfer crosses between breeds of divergent size would affect pregnancy-related development of maternal insulin resistance in midgestation, thereby influencing fetal growth. Following superovulation, embryos were surgically collected 6 d postmating and transferred to recipients on the same day. Between- and within-breed transfers were performed. Between 60 and 70 d of pregnancy overnight-fasted ewes underwent hyperinsulinemic-euglycemic clamps for assessment of insulin sensitivity. Maternal insulin sensitivity did not vary with transferred lamb breed. Overall, Cheviot ewes tended to have higher fasting glucose (P = 0.068), fasting insulin (P = 0.052), and steady-state glucose (P = 0.065) concentrations than Suffolk ewes at the stage of pregnancy studied. As expected, transferred between-breed Suffolk lambs were born lighter (P = 0.014), and transferred between-breed Cheviot lambs tended to be heavier at birth (P = 0.056) than respective lambs transferred within breed. Midgestation insulin sensitivity does not appear to be a major factor constraining growth of large breed sheep fetus transferred into smaller breed or a factor in releasing constraint in growth of a small breed fetus within a larger breed ewe. However, as embryo size is already different between transferred groups by 19 d, factors other than maternal gestational insulin resistance may determine fetal growth in this embryo transfer paradigm.


Asunto(s)
Peso al Nacer , Tamaño Corporal , Transferencia de Embrión/veterinaria , Resistencia a la Insulina/fisiología , Preñez , Ovinos/fisiología , Animales , Animales Recién Nacidos , Femenino , Embarazo
15.
Physiol Genomics ; 46(15): 560-70, 2014 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-24893875

RESUMEN

The mammary gland is a complex tissue consisting of multiple cell types which, over the lifetime of an animal, go through repeated cycles of development associated with pregnancy, lactation and involution. The mammary gland is also known to be sensitive to maternal programming by environmental stimuli such as nutrition. The molecular basis of these adaptations is of significant interest, but requires robust methods to measure gene expression. Reverse-transcription quantitative PCR (RT-qPCR) is commonly used to measure gene expression, and is currently the method of choice for validating genome-wide expression studies. RT-qPCR requires the selection of reference genes that are stably expressed over physiological states and treatments. In this study we identify suitable reference genes to normalize RT-qPCR data for the ovine mammary gland in two physiological states; late pregnancy and lactation. Biopsies were collected from offspring of ewes that had been subjected to different nutritional paradigms during pregnancy to examine effects of maternal programming on the mammary gland of the offspring. We evaluated eight candidate reference genes and found that two reference genes (PRPF3 and CUL1) are required for normalising RT-qPCR data from pooled RNA samples, but five reference genes are required for analyzing gene expression in individual animals (SENP2, EIF6, MRPL39, ATP1A1, CUL1). Using these stable reference genes, we showed that TET1, a key regulator of DNA methylation, is responsive to maternal programming and physiological state. The identification of these novel reference genes will be of utility to future studies of gene expression in the ovine mammary gland.


Asunto(s)
Perfilación de la Expresión Génica , Lactancia/genética , Glándulas Mamarias Animales/metabolismo , Fenómenos Fisiologicos Nutricionales Maternos , Preñez , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Animales , Metilación de ADN , Femenino , Expresión Génica , Regulación de la Expresión Génica , Modelos Genéticos , Embarazo , Ovinos , Oveja Doméstica/genética
16.
Phys Rev Lett ; 112(17): 172701, 2014 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-24836240

RESUMEN

Single-neutron states in (133)Sn and (209)Pb, which are analogous to single-electron states outside of closed atomic shells in alkali metals, were populated by the ((9)Be, (8)Be) one-neutron transfer reaction in inverse kinematics using particle-γ coincidence spectroscopy. In addition, the s(1/2) single-neutron hole-state candidate in (131)Sn was populated by ((9)Be, (10)Be). Doubly closed-shell (132)Sn (radioactive) and (208)Pb (stable) beams were used at sub-Coulomb barrier energies of 3 MeV per nucleon. Level energies, γ-ray transitions, absolute cross sections, spectroscopic factors, asymptotic normalization coefficients, and excited-state lifetimes are reported and compared with shell-model expectations. The results include a new transition and precise level energy for the 3p(1/2) candidate in (133)Sn, new absolute cross sections for the 1h(9/2) candidate in (133)Sn and 3s(1/2) candidate in (131)Sn, and new lifetimes for excited states in (133)Sn and (209)Pb. This is the first report on excited-state lifetimes of (133)Sn, which allow for a unique test of the nuclear shell model and (132)Sn double-shell closure.

18.
Br J Surg ; 101(8): 889-98, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24676784

RESUMEN

BACKGROUND: The aim of this review is to introduce the topic of next-generation DNA sequencing, a new technology that is being introduced into clinical practice, and to explain the potential impact for breast cancer surgeons and the wider breast cancer multidisciplinary team. METHODS: The PubMed database was used to identify relevant studies relating to breast cancer genetics. This evidence was then used to provide context and background information to demonstrate how next-generation sequencing (NGS) might change breast cancer practice. RESULTS: With NGS, breast cancer clinicians will know whether their patients carry high-risk mutations in genes, such as BRCA1 or BRCA2, before the start of treatment. This could alter treatment decisions; for instance, more women might opt for mastectomy instead of breast-conserving surgery, or for bilateral rather than unilateral surgery. CONCLUSION: The introduction of NGS will have a significant impact on breast cancer services in the near future. Speed of testing will improve in regions of the world where NGS is adopted in place of conventional sequencing, and, as costs decrease, genetic testing will also become accessible and realistic in less well funded health economies. This will create opportunities to improve patient treatment and challenges for the breast cancer multidisciplinary team.


Asunto(s)
Neoplasias de la Mama/genética , Análisis de Secuencia de ADN/tendencias , Neoplasias de la Mama/cirugía , Detección Precoz del Cáncer/métodos , Femenino , Genes BRCA1/fisiología , Genes BRCA2/fisiología , Pruebas Genéticas , Humanos , Mastectomía/métodos , Mutación/genética , Terapia Neoadyuvante/métodos , Medición de Riesgo , Factores de Riesgo
19.
J Anim Sci ; 91(2): 676-84, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23230109

RESUMEN

Studies using sheep models indicate that the fetal mammary gland is sensitive to maternal nutrition during gestation; however, results have been inconsistent and do not identify critical feeding periods. This study aimed to clarify previous findings by partitioning the period of maternal nutritional manipulation into 2 stages: early and mid-to-late pregnancy. Sixty-six twin-born, twin-bearing ewes, born to dams that were fed either submaintenance, maintenance, or ad libitum during early pregnancy (d 21 to 50 of pregnancy; SmP21-50, MP21-50, or AdP21-50, respectively) and then either maintenance or ad libitum during mid-to-late pregnancy (d 50 to 140 of pregnancy; MP50-140 or AdP50-140, respectively) were milked once a week, starting from d 7 ± 1 postpartum, for 7 subsequent weeks to enable estimation of daily milk yield and composition. Their lambs were weighed weekly. Ewes born to dams fed MP21-50 tended to have greater accumulated milk (P = 0.10), fat (P = 0.07), and NE (P = 0.06) yields over 50 d compared with ewes born to dams fed SmP21-50 and AdP21-50. In contrast, ewes born to dams fed AdP50-140 tended to have greater accumulated milk (P = 0.10) and lactose (P = 0.09) yields compared with ewes born to dams fed MP50-140. Grandoffspring birth weights were unaffected by granddam nutrition during pregnancy. Ewes born to dams fed AdP21-50 weaned lighter lambs (P = 0.05) than ewes born to dams fed AmP21-50 and tended to wean lighter lambs (P = 0.07) than ewes born to dams fed MP21-50 whereas there were no differences between the weaning weights of lambs (P = 0.43) from ewes born to dams fed AdP50-140 and MP50-140. Maintenance nutrition of dams during early pregnancy appears to be associated with an improved lactation performance of ewe offspring. Higher levels of nutrition during mid-to-late pregnancy also appears to improve the first-lactation performance of ewe offspring. Interestingly, although grandoffspring birth weights were unaffected, weaning weight appears to be influenced by granddam early pregnancy nutrition in a manner discordant with the lactational performance of their dam. Results from this study indicate that dam nutrition during early pregnancy can influence the lactational performance of ewe offspring and the BW at weaning of their grandoffspring, which may ultimately affect farmer profits. This highlights the importance of nutritional management of breeding ewes during this period.


Asunto(s)
Lactancia/fisiología , Fenómenos Fisiologicos Nutricionales Maternos , Leche/fisiología , Embarazo Múltiple/fisiología , Ovinos/fisiología , Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Peso Corporal/genética , Peso Corporal/fisiología , Dieta/veterinaria , Femenino , Embarazo , Ovinos/genética , Ovinos/crecimiento & desarrollo
20.
Phys Rev Lett ; 111(23): 232503, 2013 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-24476263

RESUMEN

Classical novae are expected to contribute to the 1809-keV Galactic γ-ray emission by producing its precursor 26Al, but the yield depends on the thermonuclear rate of the unmeasured 25Al(p,γ)26Si reaction. Using the ß decay of 26P to populate the key J(π)=3(+) resonance in this reaction, we report the first evidence for the observation of its exit channel via a 1741.6±0.6(stat)±0.3(syst) keV primary γ ray, where the uncertainties are statistical and systematic, respectively. By combining the measured γ-ray energy and intensity with other experimental data on 26Si, we find the center-of-mass energy and strength of the resonance to be E(r)=414.9±0.6(stat)±0.3(syst)±0.6(lit.) keV and ωγ=23±6(stat)(-10)(+11)(lit.) meV, respectively, where the last uncertainties are from adopted literature data. We use hydrodynamic nova simulations to model 26Al production showing that these measurements effectively eliminate the dominant experimental nuclear-physics uncertainty and we estimate that novae may contribute up to 30% of the Galactic 26Al.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...