30 research outputs found

    Effects of Time of Deoxyribonucleic Acid Microinjection on Gene Detection and In Vitro Development of Bovine Embryos

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    In vivo fertilized embryos were surgically collected from superovulated dairy cows to evaluate microinjection on embryo development and utilized the polymerase chain reaction technique for selection of transgenic embryos. Seventy-two percent of the embryos with visible pronuclei or nuclei were microinjected with DNA, and the remaining 28% served as uninjected controls. All embryos were cocultured with bovine oviductal epithelial cells. Mean final development scores of embryos within the same initial cell stage at collection were unaffected by microinjection. After 144 h of culture, 45% of the microinjected embryos developed to the morula or blastocyst stage. The transgene was detected in 50, 10, and 9% of demimorulae from embryos microinjected at the 1-, 2-, and 4-cell stages. Frequency of transgene detection was higher in morulae from 1-cell embryos than in morulae from 2- and 4-cell embryos. Use of in vitro coculture, embryo bisection, and polymerase chain reaction technique facilitated selection of bovine embryos that carried the transgene

    Associations between Prenatal Urinary Biomarkers of Phthalate Exposure and Preterm Birth: A Pooled Study of 16 US Cohorts

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    Importance: Phthalate exposure is widespread among pregnant women and may be a risk factor for preterm birth. Objective: To investigate the prospective association between urinary biomarkers of phthalates in pregnancy and preterm birth among individuals living in the US. Design, Setting, and Participants: Individual-level data were pooled from 16 preconception and pregnancy studies conducted in the US. Pregnant individuals who delivered between 1983 and 2018 and provided 1 or more urine samples during pregnancy were included. Exposures: Urinary phthalate metabolites were quantified as biomarkers of phthalate exposure. Concentrations of 11 phthalate metabolites were standardized for urine dilution and mean repeated measurements across pregnancy were calculated. Main Outcomes and Measures: Logistic regression models were used to examine the association between each phthalate metabolite with the odds of preterm birth, defined as less than 37 weeks of gestation at delivery (n = 539). Models pooled data using fixed effects and adjusted for maternal age, race and ethnicity, education, and prepregnancy body mass index. The association between the overall mixture of phthalate metabolites and preterm birth was also examined with logistic regression. G-computation, which requires certain assumptions to be considered causal, was used to estimate the association with hypothetical interventions to reduce the mixture concentrations on preterm birth. Results: The final analytic sample included 6045 participants (mean [SD] age, 29.1 [6.1] years). Overall, 802 individuals (13.3%) were Black, 2323 (38.4%) were Hispanic/Latina, 2576 (42.6%) were White, and 328 (5.4%) had other race and ethnicity (including American Indian/Alaskan Native, Native Hawaiian, >1 racial identity, or reported as other). Most phthalate metabolites were detected in more than 96% of participants. Higher odds of preterm birth, ranging from 12% to 16%, were observed in association with an interquartile range increase in urinary concentrations of mono-n-butyl phthalate (odds ratio [OR], 1.12 [95% CI, 0.98-1.27]), mono-isobutyl phthalate (OR, 1.16 [95% CI, 1.00-1.34]), mono(2-ethyl-5-carboxypentyl) phthalate (OR, 1.16 [95% CI, 1.00-1.34]), and mono(3-carboxypropyl) phthalate (OR, 1.14 [95% CI, 1.01-1.29]). Among approximately 90 preterm births per 1000 live births in this study population, hypothetical interventions to reduce the mixture of phthalate metabolite levels by 10%, 30%, and 50% were estimated to prevent 1.8 (95% CI, 0.5-3.1), 5.9 (95% CI, 1.7-9.9), and 11.1 (95% CI, 3.6-18.3) preterm births, respectively. Conclusions and Relevance: Results from this large US study population suggest that phthalate exposure during pregnancy may be a preventable risk factor for preterm delivery

    Gold standard or fool's gold: the pursuit of certainty in experimental criminology

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    This article assesses some of the claims made for experimental research in the field of rehabilitation of offenders. It suggests that both policy officials and evaluators have tended to over-invest financially and intellectually in a technocratic model of reducing reoffending that emphasizes programmes for offenders, and to under-invest in models that see the process as a complex ‘people changing’ skill. It argues that the complexity of this process renders it hard to evaluate using experimental methods of evaluation such as randomized controlled trials (RCTs). RCTs provide strong internal validity, but in complex settings offer weak external validity, making it hard to generalize from the experimental setting to other settings. The article suggests that the proper role for evaluative research in this field should be seen as building and testing middle-level theories about how best to change offenders’ behaviour

    Out of this world : the advent of the satellite tracking of offenders in England and Wales

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    In September 2004, the Home Office established three pilot programmes to test the efficacy of the satellite tracking of offenders, a new form of electronic monitoring. Satellite tracking, and the monitoring of exclusion zones which it permits, had been legislated for in the Criminal Justice and Court Services Act 2000, but the Home Office waited until putatively reliable technology – more reliable than that initially used for tracking in the USA – was available before commencing the pilots. Its arrival was formally announced in the context of a major review of ‘correctional services’, in which electronic monitoring generally is given a clearer strategic role than it has had hitherto in England and Wales. Although snippets of information about satellite tracking were drip fed into the media in the run up to the launch of the pilots, this has been a most under-deliberated initiative. This article was completed just before the commencement of the pilots and aims primarily to open up debate about this new measure. It also argues that the emergence of satellite tracking – monitoring movement rather than just single locations – sheds light on the development of electronic monitoring more generally, whose implications for more humanistic approaches to offender supervision, such as probation, are still not fully appreciated
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