Rate of Dimer Formation in Stable Colloidal Solutions Quantified Using an Attractive Interparticle Force.

We describe an optomagnetic cluster experiment to understand and control the interactions between particles over a wide range of time scales. Aggregation is studied by magnetically attracting particles into dimers and by quantifying the number of dimers that become chemically bound within a certain time interval. An optomagnetic readout based on light scattering of rotating clusters is used to measure dimer formation rates. Magnetic field settings, that is, field rotation frequency, field amplitude, and on- and off-times, have been optimized to independently measure both the magnetically induced dimers and chemically bound dimers. The chemical aggregation rate is quantified in solutions with different pH and ionic strengths. The measured rates are extrapolated to effective dimer formation rates in the absence of force, showing that aggregation rates can be quantified over several orders of magnitude, including conditions of very low chemical reactivity.

Effect of a cluster randomised team training intervention on adverse perinatal and maternal outcomes: a stepped wedge study.

OBJECTIVE: To study the effect of an intervention based on Crew Resource Management team training, including a tool for structured communication, on adverse perinatal and maternal outcomes. DESIGN: Stepped wedge. SETTING: The Netherlands. POPULATION OR SAMPLE: Registry data of 8123 women referred from primary care to a hospital during childbirth, at ≥ 32.0 weeks of singleton gestation and with no congenital abnormalities, in the period 2012-15. METHODS: Obstetric teams of five hospitals and their surrounding primary-care midwifery practices participated in the intervention. In total, 49 team training sessions were organised for 465 care professionals (75.5% participated). Adverse perinatal and maternal outcomes before, during and after the intervention were analysed using multivariate logistic regression analyses. MAIN OUTCOME MEASURES: Adverse Outcome Index (AOI-5), a composite measure involving; intrapartum or neonatal death, admission to neonatal intensive care unit, Apgar < 7 at 5 minutes, postpartum haemorrhage and/or perineal tear. RESULTS: In total, an AOI-5 score was reported in 11.3% of the study population. No significant difference was found in the incidence of the AOI-5 score after the intervention compared with before the intervention (OR 1.07: 95% CI 0.92-1.24). CONCLUSIONS: We found no effect of the intervention on adverse perinatal and maternal outcomes for women who were referred during childbirth. Team training is appreciated in practice, but evidence on the long-term impact is still limited. Upcoming studies should build on previous research and consider more sensitive outcome measures. TWEETABLE ABSTRACT: A cluster randomised team training intervention showed no effect on adverse perinatal and maternal outcomes for women referred during childbirth.

Cardiotocography in practice: a qualitative study to explore obstetrical care professionals' experiences with using cardiotocography information in Dutch practice.

OBJECTIVE: This study aimed to explore obstetric care professionals' experiences with using cardiotocograph (CTG) information and how they employ this tool in their practice. DESIGN: Qualitative study, involving 30 semi-structured interviews and two focus group sessions. Conventional content analysis was used for data analysis. SETTING: Amsterdam University Medical Centers in the Netherlands. PARTICIPANTS: In total, 43 care professionals participated. The respondents included obstetricians, residents in obstetrics and gynaecology, junior physicians, clinical midwives and nurses. FINDINGS: Three main categories were identified that influenced the use of cardiotocography in practice; (1) individual characteristics involving knowledge, experience and personal beliefs; (2) teams involving collaboration in and between shifts and (3) work environment involving equipment, culture and continuing development. CONCLUSION: This study underlines the importance of teamwork when working with cardiotocography in practice. There is a particular need to create shared responsibility among team members for cardiotocography interpretation and appropriate management, which should be addressed in educational programmes and regular multidisciplinary meetings, to allow learning from colleagues' perspectives.

Appropriateness of different pedagogical approaches to road safety education for children with Developmental Coordination Disorder (DCD).

BACKGROUND: In 2016, 29% of pedestrians killed or seriously injured on the roads in Great Britain were under 15 years of age. Children with Developmental Coordination Disorder (DCD), a chronic disorder affecting the acquisition and execution of motor skills, may be more vulnerable at the roadside than typically developing (TD) children. Current methods used to teach road safety are typically knowledge-based and do not necessarily improve behaviour in real traffic situations. Virtual reality road crossing tasks may be a viable alternative. AIMS/METHODS: The present study aimed to test the road crossing accuracy of children with and without DCD in virtual reality tasks that varied the viewpoint to simulate the teaching methods currently used in road safety educational programmes. Twenty-one children with DCD and twenty-one age and gender matched TD peers were required to locate the safest road crossing sites in two conditions: allocentric (aerial viewpoint) and egocentric (first-person viewpoint). PROCEDURES/OUTCOMES: All children completed both conditions and were required to navigate either themselves or an avatar across the road using the safest crossing route. The primary outcome was accuracy defined as the number of trials, out of 10, on which the child successfully identified and used the safest crossing route. RESULTS/CONCLUSIONS: Children with DCD performed equally poorly in both conditions, while TD children were significantly more accurate in the egocentric condition. This difference cannot be explained by self-reported prior road crossing education, practice or confidence. IMPLICATIONS: While TD children may benefit from the development of an egocentric virtual reality road crossing task, multimodal methods may be needed to effectively teach road safety to children with DCD.

Feline mammary tumors: a case-control study of hormonal factors.

Feline mammary carcinomas are, like human breast cancers, spontaneous, locally infiltrative and metastasizing tumors. Therefore, this tumor disease in the cat can serve as a pathogenetic and experimental-therapeutic model for the human counterpart. In the cat, as in the woman, little is so far known with certainty about the hormonal background of mammary tumors. In order to elucidate the role of endogenous and exogenous hormonal factors, a case-control study was conducted. Data on age, history of castration, parity and progestogen administration were compared in cats with malignant or benign mammary tumors on one hand, and in a control group on the other. The statistical relative risks and their significance were assessed using conditional logistic regression analysis. In our study there was a tendency for mammary carcinomas to be found in cats that were older than those bearing benign mammary tumors. Ovariectomy was found to protect against mammary carcinomas but not against benign mammary tumors. No association between parity and mammary tumor risk was found. Regular administration of progestogens was associated with an increased risk of both mammary carcinoma and benign mammary tumors. However, this was not true of irregular progestogen administration and, in general, the administration of progestogens was not associated with an earlier appearance of mammary tumors.

[The significance of ovariectomy and progestagens in the development of mammary carcinoma in cats]. / Over de betekenis van ovarïectomie en progestativa voor het ontstaan van het mammacarinoom bij de kat.

Mammary carcinoma in the cat has a poor prognosis. Because of metastasis and local malignity, these tumours are of relevance not only to veterinary practice but also to comparative research as a model to study possible therapies and the aetiology and pathogenesis of the disease. Little is known about the development of mammary tumours in humans and companion animals. A case-control study was carried out to learn more about the role of endogenous and exogenous sex hormones. In the cat, ovariectomy (RR 0.36) had a clear protective effect against the development of mammary carcinoma, whereas regular administration of progestogens clearly increased the risk of carcinoma development (RR 2.81). Our results show that with regard to the evidence of mammary carcinoma, oestrus prevention by ovariectomy is to preferred to the administration of progestogens.