Near-field deformation of a liquid interface by atomic force microscopy.

We experiment the interaction between a liquid puddle and a spherical probe by Atomic Force Microscopy (AFM) for a probe radius R ranging from 10 nm to 30 µm. We have developed a new experimental setup by coupling an AFM with a high-speed camera and an inverted optical microscope. Interaction force-distance curves (in contact mode) and frequency shift-distance curves (in frequency modulation mode) are measured for different bulk model liquids for which the probe-liquid Hamaker constant H_{pl} is known. The experimental results, analyzed in the frame of the theoretical model developed in Phys. Rev. Lett. 108, 106104 (2012)PRLTAO0031-900710.1103/PhysRevLett.108.106104 and Phys. Rev. E 85, 061602 (2012)PLEEE81539-375510.1103/PhysRevE.85.061602, allow to determine the "jump-to-contact" critical distance d_{min} below which the liquid jumps and wets the probe. Comparison between theory and experiments shows that the probe-liquid interaction at nanoscale is controlled by the liquid interface deformation. This work shows a very good agreement between the theoretical model and the experiments and paves the way to experimental studies of liquids at the nanoscale.

[Prevalence, severity, and predictors of bronchopulmonary dysplasia in a cohort of very preterm infants]. / Prévalence, gravité et facteurs prédictifs de la dysplasie bronchopulmonaire dans une cohorte ultramarine de grands prématurés.

OBJECTIVES: The aim of this retrospective cohort study was to determine the prevalence and severity of BPD and its predictors in a regional cohort of very preterm (VP) infants in Reunion Island. METHODS: All autochthonous VP infants, live-born before the 33rd week of gestation (WG) between 1st January 2008 and 31st December 2009, were eligible for the study. Only VP infants surviving at least 28 days, for whom the parameters were known from birth, were included in the case-control study of predictors of moderate to severe BPD (BPDmo/s). RESULTS: In VP infants less than 33 WG, the rate of overall BPD (3 grades of severity) was 30.7%. Among those who survived 28 days or more, the rate of BPDmo/s was 13.1% (95%CI: 10.2-15.9%). In VP infants less than 32 WG that survived at 36 WG, the prevalence of BPDmo/s was 18.2% (95% CI: 14.2-22.1%). In a fixed-effect logistic model, adjusted for gestational age, postnatal growth, and the mode of ventilation at 24h, 4 key factors were predictive of BDPmo/s: small for gestational age, surfactant, delayed energy intake, and late-onset neonatal infection. In a mixed-effect logistic model adjusted for these same cofactors, the site was associated with BPDmo/s, in line with a center-effect. CONCLUSION: The prevalence of BPDmo/s in the mixed-race population of Reunion Island is consistent with those observed in Europe but were site-specific. In our setting, predictors of individual BPDmo/s are similar to those already identified.

Abnormal inspiratory depth in Phox2a haploinsufficient mice.

Mutations of genes encoding Phox2a or Phox2b transcription factors induce modifications of different brainstem neuronal networks. Such modifications are associated with defects in breathing behavior at birth. In particular, an abnormal breathing frequency is observed in Phox2a-/- mutant mice, resulting from abnormal development of the locus coeruleus (LC) nucleus. However, the role of Phox2a proteins in the establishment of respiratory neuronal pathways is unknown, largely because mutants die shortly after birth. In the present study, we examined the effects of a haploinsufficiency of the Phox2a gene. Phox2a heterozygotes survive and exhibit a significantly larger inspiratory volume both during normoxic breathing and in response to hypoxia and a delayed maturation of inspiratory duration compared to wild-type animals. This phenotype accompanied by an unaltered frequency is evident at birth and persists until at least postnatal day 10. Morphological analyses of Phox2a+/- animals revealed no anomaly in the LC region, but highlighted an increase in the number of cells expressing tyrosine hydroxylase enzyme, a marker of chemoafferent neurons, in the petrosal sensory ganglion. These data indicate that Phox2a plays a critical role in the ontogeny of the reflex control of inspiration.

The USA's nurse managers and UK's ward sisters: critical roles for empowerment.

The nurse manager/ward sister role is becoming endangered as many of these nurses are being asked to take fiscal and personnel responsibility for multiple units/programmes and supervise more non-registered nursing staff. Loss of this important nurse manager/ward sister role could severely decrease nursing's voice in the development and implementation of policies that affect nurses and the care they deliver. The authors review 20 years of literature from both the USA and the UK regarding supportive supervision and the role of the nurse manager/ward sister. Nurse managers/ward sisters were found to be key individuals within the entire health-care organization. Nurse managers/ward sisters can empower the nurses they supervise to initiate changes that will improve patient care. Nurse managers/ward sisters can also improve the working conditions and thus increase the job satisfaction and retention of those they supervise. Strategies for being more supportive of these overworked and endangered nurse managers/ward sisters are suggested.

Breaking through the 'Darleck syndrome'.

This article shares the author's concern for the future of nurse education especially in relation to student nurses gaining clinical experience. In the light of Project 2000 there are varied and exciting basic nurse education courses being planned and implemented throughout the UK that aim to develop the student nurse into an open, responsive, caring professional. All the bright ideas and hard work that nurse educationalists are investing in the new courses will come to nought however, if equivalent time, energy and bright ideas are not invested in updating and refreshing experienced nurses. This article explores some of these issues.