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1.
Phys Rev Lett ; 130(19): 195101, 2023 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-37243644

RESUMEN

We present results from pulsed-power driven differentially rotating plasma experiments designed to simulate physics relevant to astrophysical disks and jets. In these experiments, angular momentum is injected by the ram pressure of the ablation flows from a wire array Z pinch. In contrast to previous liquid metal and plasma experiments, rotation is not driven by boundary forces. Axial pressure gradients launch a rotating plasma jet upward, which is confined by a combination of ram, thermal, and magnetic pressure of a surrounding plasma halo. The jet has subsonic rotation, with a maximum rotation velocity 23±3 km/s. The rotational velocity profile is quasi-Keplerian with a positive Rayleigh discriminant κ^{2}∝r^{-2.8±0.8} rad^{2}/s^{2}. The plasma completes 0.5-2 full rotations in the experimental time frame (∼150 ns).

2.
Hum Reprod ; 37(12): 2908-2920, 2022 11 24.
Artículo en Inglés | MEDLINE | ID: mdl-36166702

RESUMEN

STUDY QUESTION: Is the metabolic health of men conceived using ICSI different to that of IVF and spontaneously conceived (SC) men? SUMMARY ANSWER: ICSI-conceived men aged 18-24 years, compared with SC controls, showed differences in some metabolic parameters including higher resting diastolic blood pressure (BP) and homeostasis model assessment for insulin resistance (HOMA-IR) scores, although the metabolic parameters of ICSI- and IVF-conceived singleton men were more comparable. WHAT IS KNOWN ALREADY: Some studies suggest that IVF-conceived offspring may have poorer cardiovascular and metabolic profiles than SC children. Few studies have examined the metabolic health of ICSI-conceived offspring. STUDY DESIGN, SIZE, DURATION: This cohort study compared the metabolic health of ICSI-conceived men to IVF-conceived and SC controls who were derived from prior cohorts. Participants included 121 ICSI-conceived men (including 100 singletons), 74 IVF-conceived controls (all singletons) and 688 SC controls (including 662 singletons). PARTICIPANTS/MATERIALS, SETTING, METHODS: Resting systolic and diastolic BP (measured using an automated sphygmomanometer), height, weight, BMI, body surface area and fasting serum metabolic markers including fasting insulin, glucose, total cholesterol, high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol, triglycerides, highly sensitive C-reactive protein (hsCRP) and HOMA-IR were compared between groups. Data were analysed using multivariable linear regression adjusted for various covariates including age and education level. MAIN RESULTS AND THE ROLE OF CHANCE: After adjusting for covariates, compared to 688 SC controls, 121 ICSI-conceived men had higher diastolic BP (ß 4.9, 95% CI 1.1-8.7), lower fasting glucose (ß -0.7, 95% CI -0.9 to -0.5), higher fasting insulin (ratio 2.2, 95% CI 1.6-3.0), higher HOMA-IR (ratio 1.9, 95% CI 1.4-2.6), higher HDLC (ß 0.2, 95% CI 0.07-0.3) and lower hsCRP (ratio 0.4, 95% CI 0.2-0.7) levels. Compared to 74 IVF-conceived singletons, only glucose differed in the ICSI-conceived singleton men (ß -0.4, 95% CI -0.7 to -0.1). No differences were seen in the paternal infertility subgroups. LIMITATIONS, REASONS FOR CAUTION: The recruitment rate of ICSI-conceived men in this study was low and potential for recruitment bias exists. The ICSI-conceived men, the IVF-conceived men and SC controls were from different cohorts with different birth years and different geographical locations. Assessment of study groups and controls was not contemporaneous, and the measurements differed for some outcomes (BP, insulin, glucose, lipids and hsCRP). WIDER IMPLICATIONS OF THE FINDINGS: These observations require confirmation in a larger study with a focus on potential mechanisms. Further efforts to identify whether health differences are due to parental characteristics and/or factors related to the ICSI procedure are also necessary. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by an Australian National Health and Medical Research Council Partnership Grant (NHMRC APP1140706) and was partially funded by the Monash IVF Research and Education Foundation. S.R.C. was supported through an Australian Government Research Training Program Scholarship. R.J.H. is supported by an NHMRC project grant (634457), and J.H. and R.I.M. have been supported by the NHMRC as Senior and Principal Research Fellows respectively (J.H. fellowship number: 1021252; R.I.M. fellowship number: 1022327). L.R. is a minority shareholder and the Group Medical Director for Monash IVF Group, and reports personal fees from Monash IVF Group and Ferring Australia, honoraria from Ferring Australia and travel fees from Merck Serono and MSD and Guerbet; R.J.H. is the Medical Director of Fertility Specialists of Western Australia and has equity in Western IVF; R.I.M. is a consultant for and shareholder of Monash IVF Group and S.R.C. reports personal fees from Besins Healthcare and nonfinancial support from Merck outside of the submitted work. The remaining authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.


Asunto(s)
Resistencia a la Insulina , Insulinas , Niño , Masculino , Humanos , Inyecciones de Esperma Intracitoplasmáticas/métodos , Estudios de Cohortes , Proteína C-Reactiva , Australia , Semen , Glucosa , Colesterol , Fertilización In Vitro/métodos
3.
Phys Rev Lett ; 129(22): 225001, 2022 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-36493430

RESUMEN

We present a study of perpendicular subcritical shocks in a collisional laboratory plasma. Shocks are produced by placing obstacles into the supermagnetosonic outflow from an inverse wire array z pinch. We demonstrate the existence of subcritical shocks in this regime and find that secondary shocks form in the downstream. Detailed measurements of the subcritical shock structure confirm the absence of a hydrodynamic jump. We calculate the classical (Spitzer) resistive diffusion length and show that it is approximately equal to the shock width. We measure little heating across the shock (<10% of the ion kinetic energy) which is consistent with an absence of viscous dissipation.

4.
Ultrasound Obstet Gynecol ; 56(2): 215-224, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-31625225

RESUMEN

OBJECTIVES: To perform individual record linkage of women undergoing screening with cell-free DNA (cfDNA), combined first-trimester screening (CFTS), second-trimester serum screening (STSS), and/or prenatal and postnatal cytogenetic testing with the aim to (1) obtain population-based estimates of utilization of prenatal screening and invasive diagnosis, (2) analyze the performance of different prenatal screening strategies, and (3) report the residual risk of any major chromosomal abnormality following a low-risk aneuploidy screening result. METHODS: This was a retrospective study of women residing in the state of Victoria, Australia, who underwent prenatal screening or invasive prenatal diagnosis in 2015. Patient-funded cfDNA referrals from multiple providers were merged with state-wide results for government-subsidized CFTS, STSS and invasive diagnostic procedures. Postnatal cytogenetic results from products of conception and infants up to 12 months of age were obtained to ascertain cases of false-negative screening results and atypical chromosomal abnormalities. Individual record linkage was performed using LinkageWizTM . RESULTS: During the study period, there were 79 140 births and 66 166 (83.6%) women underwent at least one form of aneuploidy screening. Linkage data were complete for 93.5% (n = 61 877) of women who underwent screening, and of these, 73.2% (n = 45 275) had CFTS alone, 20.2% (n = 12 486) had cfDNA alone; 5.3% (n = 3268) had STSS alone, 1.3% (n = 813) had both CFTS and cfDNA, and < 0.1% (n = 35) had both STSS and cfDNA. CFTS had a combined sensitivity for trisomies 21 (T21), 18 (T18) and 13 (T13) of 89.57% (95% CI, 82.64-93.93%) for a screen-positive rate (SPR) of 2.94%. There were 12 false-negative results in the CFTS pathway, comprising 10 cases of T21, one of T18 and one of T13. cfDNA had a combined sensitivity for T21, T18 and T13 of 100% (95% CI, 95.00-100%) for a SPR of 1.21%. When high-risk cfDNA results for any chromosome (including the sex chromosomes) and failed cfDNA tests were treated as screen positives, the SPR for cfDNA increased to 2.42%. The risk of any major chromosomal abnormality (including atypical abnormalities) detected on prenatal or postnatal diagnostic testing after a low-risk screening result was 1 in 1188 for CFTS (n = 37) and 1 in 762 for cfDNA (n = 16) (P = 0.13). The range of chromosomal abnormalities detected after a low-risk cfDNA result included pathogenic copy-number variants (n = 6), triploidy (n = 3), rare autosomal trisomies (n = 3) and monosomy X (n = 2). CONCLUSIONS: Our state-wide record-linkage analysis delineated the utilization and clinical performance of the multitude of prenatal screening pathways available to pregnant women. The sensitivity of cfDNA for T21, T18 and T13 was clearly superior to that of CFTS. While there was no statistically significant difference in the residual risk of any major chromosomal abnormality after a low-risk CFTS or cfDNA result, there were fewer live infants diagnosed with a major chromosomal abnormality in the cfDNA cohort. These data provide valuable population-based evidence to inform practice recommendations and health policies. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.


Asunto(s)
Ácidos Nucleicos Libres de Células , Aberraciones Cromosómicas/embriología , Trastornos de los Cromosomas/diagnóstico , Pruebas Genéticas/estadística & datos numéricos , Diagnóstico Prenatal/estadística & datos numéricos , Adulto , Aneuploidia , Trastornos de los Cromosomas/embriología , Análisis Citogenético/métodos , Análisis Citogenético/estadística & datos numéricos , Reacciones Falso Negativas , Femenino , Pruebas Genéticas/métodos , Humanos , Registro Médico Coordinado , Valor Predictivo de las Pruebas , Embarazo , Primer Trimestre del Embarazo/genética , Diagnóstico Prenatal/métodos , Estudios Retrospectivos , Sensibilidad y Especificidad , Victoria
5.
Ultrasound Obstet Gynecol ; 53(4): 503-511, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29877030

RESUMEN

OBJECTIVE: To assess trends in ultrasound-indicated prenatal diagnostic testing performed over the past two decades in the Australian state of Victoria, in the context of rapidly changing practices in aneuploidy screening and chromosome analysis. METHODS: This was a retrospective analysis of all ultrasound-indicated prenatal diagnostic testing (amniocentesis and chorionic villus sampling) performed in the state of Victoria between 1994 and 2016. Ultrasound indications for testing included: fetal structural abnormality, fetal death, fetal growth restriction, abnormal amniotic fluid volume, genetic 'soft marker' and unspecified ultrasound abnormality. Maternal age, indication for testing, type of diagnostic procedure, gestational age, type of chromosome analysis (G-banded karyotyping or chromosomal microarray (CMA)) and test results were obtained. Diagnostic yield (i.e. percentage of tests yielding a major abnormality) was analyzed by year, maternal age and gestational age. Statistical analysis was performed using the χ2 tests for trend or difference in proportions, as appropriate. RESULTS: During the 23-year study period, 1 533 317 births were recorded and 16 152 diagnostic procedures were performed for the primary indication of ultrasound abnormality. In recent years, ultrasound abnormality became the most common indication for prenatal invasive testing (29.4% of diagnostic tests between 2013 and 2016) due to a steep decline in testing for other indications such as positive result on combined first-trimester screening or advanced maternal age alone. In 2016, over 95% of ultrasound-indicated procedures were performed with CMA; among these, pathogenic copy number variant (CNV) was the most common (3.5%) abnormality detected, followed by trisomy 21 (2.8%). The diagnostic yield of ultrasound-indicated tests performed < 16 weeks was significantly higher than that of tests performed after 20 weeks (31.5% vs 9.0%). CONCLUSIONS: Ultrasound-indicated invasive testing is contributing to prenatal diagnosis in new ways in the genomic era. A pathogenic CNV is now the most likely diagnosis after ultrasound-indicated testing, rather than trisomy 21 or other whole-chromosome aneuploidy. Despite steady improvements in first-trimester screening for aneuploidy, the diagnostic yield of ultrasound-indicated tests > 20 weeks has remained stable due to increased utilization of CMA. Procedures performed for structural abnormalities < 16 weeks continue to have the highest diagnostic yield, supporting the benefits of early fetal structural assessment at 11-13 weeks. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.


Asunto(s)
Amniocentesis/estadística & datos numéricos , Muestra de la Vellosidad Coriónica/estadística & datos numéricos , Ultrasonografía Prenatal/estadística & datos numéricos , Adulto , Aneuploidia , Ácidos Nucleicos Libres de Células , Variaciones en el Número de Copia de ADN , Síndrome de Down/diagnóstico , Femenino , Humanos , Edad Materna , Vigilancia de la Población , Embarazo , Estudios Retrospectivos , Victoria
6.
Ultrasound Obstet Gynecol ; 51(4): 487-492, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29226487

RESUMEN

OBJECTIVES: To investigate by means of a population-based analysis of a cohort of women who underwent combined first-trimester screening (CFTS), changes in uptake of invasive prenatal diagnosis according to risk of trisomy 21 (T21) on CFTS, and prevalence and methods for ascertainment of atypical chromosome abnormalities. METHODS: This was a retrospective cohort study using state-wide prenatal datasets from Victoria, Australia. A three-step approach was taken to analyze the data: (1) linkage of records between serum screening and diagnostic results; (2) comparison of rates of diagnostic testing according to CFTS T21 risk result category in a 2014-2015 cohort with those of a historical 2002-2004 cohort; (3) detailed analysis of atypical abnormalities in the 2014-2015 group according to CFTS T21 risk result, individual serum analyte level and other indications for invasive diagnostic testing. RESULTS: In 2014-2015, there were 100 418 CFTS results issued for 146 776 births (68.4%). The overall prevalence of atypical chromosome abnormalities in the entire CFTS cohort was 0.10% and was highest in those with CFTS T21 risk > 1 in 10 (4.6%), or serum analyte levels < 0.2 multiples of the median (MoM) (6.9% for pregnancy-associated plasma protein-A (PAPP-A) and 5.2% for beta-human chorionic gonadotropin (ß-hCG)). Almost half (49.2%) of women with PAPP-A < 0.2 MoM had a risk for T21 on CFTS of less than 1 in 100. The majority (55%) of atypical abnormalities occurred in women with CFTS T21 risk below 1 in 300, and were most commonly detected on ultrasound examination (47.1%). CONCLUSION: Concerns regarding missed diagnoses of atypical chromosome abnormalities when non-invasive prenatal testing is offered after a result of high risk on CFTS can be mitigated if invasive diagnostic testing is offered to those women with CFTS T21 risk of > 1 in 100, serum PAPP-A or ß-hCG < 0.2 MoM, or ultrasound-detected abnormality. This has implications for contingent models of screening. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.


Asunto(s)
Síndrome de Down/diagnóstico , Síndrome de Down/genética , Pruebas de Detección del Suero Materno/estadística & datos numéricos , Ultrasonografía Prenatal/estadística & datos numéricos , Adulto , Gonadotropina Coriónica Humana de Subunidad beta/sangre , Variaciones en el Número de Copia de ADN/genética , Síndrome de Down/sangre , Síndrome de Down/epidemiología , Femenino , Humanos , Tamizaje Masivo/estadística & datos numéricos , Valor Predictivo de las Pruebas , Embarazo , Primer Trimestre del Embarazo , Proteína Plasmática A Asociada al Embarazo/análisis , Prevalencia , Estudios Retrospectivos , Medición de Riesgo , Victoria/epidemiología
7.
BJOG ; 123(1): 90-7, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26108969

RESUMEN

OBJECTIVE: To analyse population-based trends over the entire history of prenatal testing for aneuploidy. DESIGN: Retrospective analysis of state-wide data sets. SETTING: Australian state of Victoria with ~70 000 annual births. POPULATION: All pregnant women undergoing invasive prenatal testing at <25 weeks' gestation from 1976 to 2013. METHODS: Analysis of three state-wide data sets: (1) Prenatal diagnosis data set of 119 404 amniocenteses and chorionic villus samplings from 1976 to 2013; (2) central serum screening laboratory data set from 1996 to 2013; (3) government birth statistics from 1976 to 2013. MAIN OUTCOME MEASURES: Annual numbers and uptake rates of invasive prenatal tests and serum screening, indications for invasive prenatal testing, prenatal diagnoses of aneuploidy, diagnostic yield of invasive tests. RESULTS: Annual numbers of invasive prenatal tests climbed steadily from 1976, then declined from 2000. In 2013, the number of invasive prenatal tests was the lowest in 25 years, while the number of trisomy 21 diagnoses was the highest ever recorded. Annual uptake of serum screening climbed from 1.6 to 83% over 1996-2013. Results from 2013 showed a high diagnostic yield (15.8%) for a low rate of invasive testing (3.4% of births). Over four decades, the number of invasive procedures performed for each diagnosis of major chromosome abnormality declined from 100 to six. CONCLUSIONS: This study demonstrates historic reductions in the proportion of women undergoing invasive testing and dramatic improvements in diagnostic yield. Monitoring the impact of new prenatal technologies on this progress remains an important research priority. TWEETABLE ABSTRACT: Invasive prenatal testing has reached historic lows due to dramatic improvements in Down syndrome screening.


Asunto(s)
Aborto Espontáneo/prevención & control , Síndrome de Down/diagnóstico , Pruebas Genéticas , Medida de Translucencia Nucal/métodos , Diagnóstico Prenatal , Adulto , Amniocentesis/efectos adversos , Australia/epidemiología , Biomarcadores/metabolismo , Gonadotropina Coriónica Humana de Subunidad beta/metabolismo , Síndrome de Down/epidemiología , Síndrome de Down/metabolismo , Femenino , Edad Gestacional , Humanos , Recién Nacido , Edad Materna , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Embarazo , Proteína Plasmática A Asociada al Embarazo/metabolismo , Estudios Retrospectivos , Victoria/epidemiología , alfa-Fetoproteínas/metabolismo
8.
BMC Public Health ; 15: 707, 2016 08 03.
Artículo en Inglés | MEDLINE | ID: mdl-27487945

RESUMEN

BACKGROUND: Although childhood obesity prevalence is stabilised in developed countries including Australia, it is continuing to rise among migrants and socially disadvantaged groups in these countries. African migrants and refugees in particular, are at high risk of obesity due to changes in their family dynamics. The aim of this study was to examine the difference between children and parental perception of family functioning, family communication, family type and parenting styles and their relationship with body mass index. METHODS: A cross-sectional parent-child dyad study was conducted among 284 African families from migrant and refugee backgrounds living in metropolitan Melbourne, Australia. Bilingual workers were trained to collect demographic, anthropometric and questionnaire data on family functioning, parenting, family type and family communication. RESULTS: Parents and children reported different levels of family dynamics. Children reported a higher prevalence of poor family functioning (61.5 %, 95 % CI: 55.6, 67.2 versus 56.8 %, 95 % CI: 49.7, 61.6) and protective family type (29 %, 95 % CI: 23.9, 34.5 vs. 13.4 %, 95 % CI: 9.9, 17.9), but a lower prevalence of authoritative parenting style (51.6 %, 95 % CI: 45.7, 57.5 vs. 63 %, 95 % CI: 57.5, 68.8) than parents. There was a positive relationship between poor family functioning and child BMI both before (ß = 1.28; 95 % CI: 0.14, 2.41; p < 0.05) and after (ß = 1.73; 95 % CI: 0.53, 2.94; p < 0.001) controlling for confounders, and an inverse relationship between consensual family type and child BMI after adjustment (ß = -1.92; 95 % CI: -3.59, -0.24; p < 0.05). There was no significant relationship between parental BMI and family functioning, communication, family type or parenting style. CONCLUSION: Children's perception of poor family functioning was associated with childhood obesity. Family interventions to reduce childhood obesity need to adopt an intergenerational approach to promote a clear understanding of family dynamics between children and parents. Unless these intergenerational challenges associated with family dynamics are clearly addressed in obesity interventions, current obesity prevention initiatives will continue to widen the childhood obesity gap in Australia.


Asunto(s)
Población Negra , Índice de Masa Corporal , Comunicación , Emigrantes e Inmigrantes , Relaciones Padres-Hijo , Responsabilidad Parental , Obesidad Infantil/etnología , Aculturación , Adolescente , Adulto , África , Concienciación , Niño , Estudios Transversales , Femenino , Humanos , Masculino , Padres , Obesidad Infantil/etiología , Prevalencia , Encuestas y Cuestionarios , Migrantes , Victoria
9.
Clin Genet ; 87(1): 21-9, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-24773164

RESUMEN

Chromosomal microarray (CMA) testing is now performed frequently in paediatric care. Although CMAs improve diagnostic yields, they increase detection of variants of unknown and uncertain clinical significance (VUS). Understanding parents', paediatricians' and genetic health professionals' (GHPs) views regarding variant disclosure may reduce the potential for communication of unwanted information. A questionnaire was designed to compare disclosure preferences of these three groups in Australia. One hundred and forty-seven parents, 159 paediatricians and 69 GHPs hold similar views with at least 89% of respondents certainly or probably favouring disclosure of all categories of variants. However, some differences were observed between health care providers (HCPs: paediatricians and GHPs) and parents, who were less sure of their disclosure preferences. There was consensus among respondent groups that knowledge of a variant of certain clinical significance would provide more practical and emotional utility compared to VUS. Compared to HCPs, parents placed more emphasis on using knowledge of a VUS when considering future pregnancies (p < 0.001). This study may help HCPs anticipate parents' preferences for genomic testing. As whole exome/genome sequencing is integrated into clinical practice, the potential for differing views of parents and HCPs should be considered when developing guidelines for result disclosure.


Asunto(s)
Cromosomas Humanos/genética , Revelación , Asesoramiento Genético/psicología , Personal de Salud/psicología , Análisis por Micromatrices/métodos , Pacientes/psicología , Análisis de Varianza , Australia , Humanos , Estadísticas no Paramétricas , Encuestas y Cuestionarios
11.
Int J Obes (Lond) ; 38(4): 480-93, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24232501

RESUMEN

There is mounting evidence that family functioning is linked to childhood overweight and obesity, and that both of these are associated with health-related behaviours and adverse health outcomes in children and adolescents. This paper systematically examines the peer-reviewed evidence regarding the relationship between child and adolescent overweight and obesity and family functioning. Peer-reviewed literature published between 1990 and 2011 hosted in Scopus, Pub Med or Psyc INFO were searched, in addition to the reference lists of included papers. Twenty-one studies met the selection criteria. Of the 17 identified cross-sectional and longitudinal studies, 12 reported significant associations between family functioning and childhood overweight and obesity. The instruments used to measure family functioning in the identified studies were heterogeneous. Poor family functioning was associated with increased risk of obesity and overweight in children and adolescents, and obese children and adolescents were more likely to come from families with poor family functioning. Aspects of family functioning which were associated with increased risk of child and adolescent obesity included poor communication, poor behaviour control, high levels of family conflict and low family hierarchy values. Half (2/4) of the identified intervention studies showed a significant relationship between family functioning and changes in child weight. The results demonstrate that family functioning is linked to obesity; however, higher level evidence and greater understanding of the mechanisms behind this relationship are required. The results indicate a need for a standardised family functioning measure applicable across populations. The results provide evidence of the value of considering family functioning in childhood obesity research and intervention.


Asunto(s)
Relaciones Familiares , Familia/psicología , Conductas Relacionadas con la Salud , Responsabilidad Parental , Obesidad Infantil/epidemiología , Obesidad Infantil/psicología , Adolescente , Índice de Masa Corporal , Peso Corporal , Niño , Preescolar , Comunicación , Estudios Transversales , Medicina Basada en la Evidencia , Conflicto Familiar , Femenino , Humanos , Masculino , Responsabilidad Parental/psicología , Obesidad Infantil/prevención & control , Pérdida de Peso
13.
Nat Commun ; 15(1): 5029, 2024 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-38866733

RESUMEN

Relativistic electron-positron plasmas are ubiquitous in extreme astrophysical environments such as black-hole and neutron-star magnetospheres, where accretion-powered jets and pulsar winds are expected to be enriched with electron-positron pairs. Their role in the dynamics of such environments is in many cases believed to be fundamental, but their behavior differs significantly from typical electron-ion plasmas due to the matter-antimatter symmetry of the charged components. So far, our experimental inability to produce large yields of positrons in quasi-neutral beams has restricted the understanding of electron-positron pair plasmas to simple numerical and analytical studies, which are rather limited. We present the first experimental results confirming the generation of high-density, quasi-neutral, relativistic electron-positron pair beams using the 440 GeV/c beam at CERN's Super Proton Synchrotron (SPS) accelerator. Monte Carlo simulations agree well with the experimental data and show that the characteristic scales necessary for collective plasma behavior, such as the Debye length and the collisionless skin depth, are exceeded by the measured size of the produced pair beams. Our work opens up the possibility of directly probing the microphysics of pair plasmas beyond quasi-linear evolution into regimes that are challenging to simulate or measure via astronomical observations.

14.
Br J Cancer ; 109(6): 1562-9, 2013 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-23942066

RESUMEN

BACKGROUND: Non-invasive imaging biomarkers underpin the development of molecularly targeted anti-cancer drugs. This study evaluates tumour apparent diffusion coefficient (ADC), measured by diffusion-weighted magnetic resonance imaging (DW-MRI), as a biomarker of response to the MEK1/2 inhibitor selumetinib (AZD6244, ARRY-142886) in human tumour xenografts. METHODS: Nude mice bearing human BRAF(V600D) WM266.4 melanoma or BRAF(V600E) Colo205 colon carcinoma xenografts were treated for 4 days with vehicle or selumetinib. DW-MRI was performed before and 2 h after the last dose and excised tumours analysed for levels of phospho-ERK1/2, cleaved caspase 3 (CC3) and necrosis. RESULTS: Selumetinib treatment induced tumour stasis and reduced ERK1/2 phosphorylation in both WM266.4 and Colo205 tumour xenografts. Relative to day 0, mean tumour ADC was unchanged in the control groups but was significantly increased by up to 1.6-fold in selumetinib-treated WM266.4 and Colo205 tumours. Histological analysis revealed a significant increase in necrosis in selumetinib-treated WM266.4 and Colo205 xenografts and CC3 staining in selumetinib-treated Colo205 tumours relative to controls. CONCLUSION: Changes in ADC following treatment with the MEK1/2 inhibitor selumetinib in responsive human tumour xenografts were concomitant with induction of tumour cell death. ADC may provide a useful non-invasive pharmacodynamic biomarker for early clinical assessment of response to selumetinib and other MEK-ERK1/2 signalling-targeted therapies.


Asunto(s)
Bencimidazoles/farmacología , Neoplasias del Colon/tratamiento farmacológico , Imagen de Difusión por Resonancia Magnética/métodos , MAP Quinasa Quinasa 1/antagonistas & inhibidores , MAP Quinasa Quinasa 2/antagonistas & inhibidores , Melanoma/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/farmacología , Animales , Línea Celular Tumoral , Neoplasias del Colon/enzimología , Femenino , Humanos , Melanoma/enzimología , Ratones , Ratones Desnudos , Terapia Molecular Dirigida , Ensayos Antitumor por Modelo de Xenoinjerto
15.
BJOG ; 120(6): 744-53, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23418853

RESUMEN

OBJECTIVES: To examine alcohol-use disorders in pregnant women and the extent of under-reporting. DESIGN: Population-based cohort study. SETTING: Western Australia. POPULATION: Women with a birth recorded on the Western Australian Midwives Notification System (1985-2006). METHODS: Mothers with an International Classification of Diseases 9/10 alcohol-related diagnosis, indicating heavy alcohol consumption, recorded on population-based health datasets (non-Aboriginal n=5,839; Aboriginal n=2,583) were identified through the Western Australian data-linkage system. This 'exposed' cohort was frequency matched (on maternal age, year of birth of offspring, Aboriginal status) with comparison mothers without an alcohol-related diagnosis (non-Aboriginal n=33,979; Aboriginal n=8,005). MAIN OUTCOME MEASURES: Trends in maternal alcohol diagnoses in relation to pregnancy for non-Aboriginal and Aboriginal women. The proportion of children diagnosed with fetal alcohol syndrome (FAS) who had a mother with an alcohol diagnosis recorded during pregnancy. RESULTS: The proportion of Aboriginal mothers in Western Australia with an alcohol diagnosis (23.1%) is ten times greater than for non-Aboriginal mothers (2.3%). There has been a six-fold increase in the percentage of non-Aboriginal births with a maternal alcohol diagnosis recorded during pregnancy and a 100-fold increase for Aboriginal births. Around 70% of the mothers of children diagnosed with FAS did not have an alcohol diagnosis recorded during pregnancy and 18% of the mothers had no record of an alcohol diagnosis. CONCLUSIONS: Maternal alcohol exposure during pregnancy is significantly under-ascertained. Given the severe risks to the fetus from heavy prenatal alcohol exposure, assessment and recording of alcohol use should be routinely undertaken in maternity and other health settings.


Asunto(s)
Trastornos Relacionados con Alcohol/epidemiología , Trastornos del Espectro Alcohólico Fetal/epidemiología , Complicaciones del Embarazo/epidemiología , Adulto , Estudios de Cohortes , Femenino , Humanos , Nativos de Hawái y Otras Islas del Pacífico , Embarazo , Factores de Riesgo , Australia Occidental/epidemiología , Adulto Joven
16.
Rev Sci Tech ; 32(2): 539-48, 2013 Aug.
Artículo en Inglés, Francés | MEDLINE | ID: mdl-24547657

RESUMEN

Animal diseases, foodborne pathogens and foodborne diseases have enormous impacts upon the health and livelihoods of producers and consumers in developing and in-transition countries. Unfortunately, the capacity for effective surveillance of infectious disease threats is often limited in these countries, leading to chronic under-reporting. This further contributes towards underestimating the effects of these diseases and an inability to implement effective control measures. However, innovative communications and diagnostic tools, as well as new analytical approaches and close cooperation within and between the animal and human health sectors, can be used to improve the coverage, quality and speed of reporting, as well as to generate more comprehensive estimates of the disease burden. These approaches can help to tackle endemic diseases and build essential surveillance capacities to address changing disease threats in the future.


Asunto(s)
Países en Desarrollo , Enfermedades Transmitidas por los Alimentos/epidemiología , Mataderos , Alimentación Animal , Animales , Participación de la Comunidad , Microbiología de Alimentos , Parasitología de Alimentos , Agencias Gubernamentales , Humanos , Comunicación Interdisciplinaria , Vigilancia de la Población , Zoonosis
17.
Br J Cancer ; 106(12): 1960-6, 2012 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-22596237

RESUMEN

BACKGROUND: Non-invasive quantitative imaging biomarkers are essential for the evaluation of novel targeted therapeutics. Before deployment in clinical trials, such imaging biomarkers require qualification, typically through pre-clinical identification of imaging-pathology correlates. METHODS: First, in investigating imaging biomarkers of invasion, the response of orthotopic murine PC3 prostate xenografts to the Src inhibitor saracatinib was assessed using susceptibility contrast MRI. Second, the longitudinal response of chemically induced rat mammary adenocarcinomas to the VEGFR2 inhibitor vandetanib was monitored by intrinsic susceptibility MRI, to identify the time window of transient vascular normalisation. RESULTS: No significant differences in fractional blood volume (%), vessel calibre (µm), native T(1) (ms) or apparent water diffusion coefficient were determined, despite reduced expression of activated Fak and paxillin in the saracatinib cohort. Treatment with vandetanib elicited a 60% antitumour response (P<0.01), 80% inhibition in vessel density (P<0.05) and reduction in hypoxia (P<0.05). There was, however, no significant change in tumour baseline R(2)* (s(-1)) or carbogen-induced ΔR(2)* with treatment. CONCLUSION: Reporting negative imaging biomarker responses is important, to avoid the risk of clinical trials using the same biomarkers being undertaken with a false expectation of success, and the abandonment of promising new therapeutics based on a false-negative imaging biomarker response being mistaken for a true-negative.


Asunto(s)
Benzodioxoles/uso terapéutico , Vasos Sanguíneos/patología , Imagen por Resonancia Magnética/métodos , Neoplasias Mamarias Experimentales/tratamiento farmacológico , Piperidinas/uso terapéutico , Neoplasias de la Próstata/tratamiento farmacológico , Proteínas Proto-Oncogénicas pp60(c-src)/antagonistas & inhibidores , Quinazolinas/uso terapéutico , Receptor 2 de Factores de Crecimiento Endotelial Vascular/antagonistas & inhibidores , Animales , Biomarcadores de Tumor , Vasos Sanguíneos/efectos de los fármacos , Hipoxia de la Célula/efectos de los fármacos , Línea Celular Tumoral , Reacciones Falso Negativas , Femenino , Humanos , Masculino , Neoplasias Mamarias Experimentales/inducido químicamente , Neoplasias Mamarias Experimentales/patología , Ratones , Terapia Molecular Dirigida , Trasplante de Neoplasias , Neoplasias de la Próstata/diagnóstico , Neoplasias de la Próstata/patología , Ratas
18.
Sci Rep ; 12(1): 18447, 2022 11 02.
Artículo en Inglés | MEDLINE | ID: mdl-36323877

RESUMEN

Resistance to anthracnose caused by the fungal pathogen Colletotrichum lentis was explored through transcriptome sequencing over a period of 24 to 96 h post-inoculation (hpi) of the partially resistant recombinant inbred lines (RIL) LR-66-528 and susceptible LR-66-524 of the crop wild relative Lens ervoides population LR-66. The development of infection vesicles and primary hyphae by C. lentis were significantly higher on susceptible RIL LR-66-524 compared to partially resistant LR-66-528 at 24 and 48 hpi, but exponential trends in fungal growth were observed between 24 to 96 hpi in both RILs. Comparison of inoculated with mock-inoculated samples revealed 3091 disease responsive genes, among which 477 were differentially expressed between the two RILs. These were clustered into six expression clusters with genes that had either high or low expression in one of the RILs. Differentially expressed genes (DEGs) were functionally annotated and included genes coding LRR and NB-ARC domain disease resistance proteins, protein detoxification, LRR receptor-like kinase family proteins, and wall-associated Ser/Thr Kinases. DEGs were compared to genes in previously published anthracnose resistance QTLs mapped in LR-66 and revealed 22 DEGs located in 3 QTLs. Expression of 21 DEGs was validated using RT-qPCR confirming expression trends in RNA-seq.


Asunto(s)
Colletotrichum , Fabaceae , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Colletotrichum/genética , Resistencia a la Enfermedad/genética , Sitios de Carácter Cuantitativo , Fabaceae/genética
19.
Hum Reprod ; 26(5): 1209-19, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21362683

RESUMEN

BACKGROUND: The use of assisted reproductive technology (ART) is now well established in many countries and the first generations of offspring are reaching maturity. We reviewed the published literature to describe the available evidence about health outcomes in ART-conceived young people who were of an adolescent age or older. METHODS: The EMBASE, Medline and PsychINFO databases were searched from January 1998 to October 2010. Key inclusion criteria were that the study sample have a mean age of ≥ 12 years or a mean follow-up period of ≥ 12 years and were conceived by ART. RESULTS: Seven publications reported physical health outcomes and 10 reported psychosocial health outcomes in ART offspring. Compared with control groups, some differences in physiological outcomes in relation to growth and development, chronic illness and risk of cancer have been reported. Overall, psychosocial studies of ART-conceived young people indicate that their cognitive function and psychological and social adjustment are similar to that of comparison groups. CONCLUSIONS: Overall, nine ART-conceived populations of this age group have been studied. Most samples included < 300 participants and methodologies varied between studies. Health information on this age group is therefore limited and the clinical significance of the findings remains unclear. Further research focusing on ART-conceived young adults is needed, particularly in relation to neurological health outcomes where no studies have been reported to date.


Asunto(s)
Adaptación Psicológica , Desarrollo del Adolescente , Técnicas Reproductivas Asistidas/psicología , Adolescente , Femenino , Estudios de Seguimiento , Humanos , Masculino , Relaciones Padres-Hijo , Estudios Retrospectivos , Factores de Riesgo , Adulto Joven
20.
Rev Sci Instrum ; 92(3): 033542, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33819991

RESUMEN

Optical collective Thomson scattering (TS) is used to diagnose magnetized high energy density physics experiments at the Magpie pulsed-power generator at Imperial College London. The system uses an amplified pulse from the second harmonic of a Nd:YAG laser (3 J, 8 ns, 532 nm) to probe a wide diversity of high-temperature plasma objects, with densities in the range of 1017-1019 cm-3 and temperatures between 10 eV and a few keV. The scattered light is collected from 100 µm-scale volumes within the plasmas, which are imaged onto optical fiber arrays. Multiple collection systems observe these volumes from different directions, providing simultaneous probing with different scattering K-vectors (and different associated α-parameters, typically in the range of 0.5-3), allowing independent measurements of separate velocity components of the bulk plasma flow. The fiber arrays are coupled to an imaging spectrometer with a gated intensified charge coupled device. The spectrometer is configured to view the ion-acoustic waves of the collective Thomson scattered spectrum. Fits to the spectra with the theoretical spectral density function S(K, ω) yield measurements of the local plasma temperatures and velocities. Fitting is constrained by independent measurements of the electron density from laser interferometry and the corresponding spectra for different scattering vectors. This TS diagnostic has been successfully implemented on a wide range of experiments, revealing temperature and flow velocity transitions across magnetized shocks, inside rotating plasma jets and imploding wire arrays, as well as providing direct measurements of drift velocities inside a magnetic reconnection current sheet.

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