Promoting breastfeeding for mothers returning to work: a guide for employers

This booklet is the third in a series of�Work�Well guides aimed at promoting health in the workplace. It outlines to employers the business benefits of encouraging mothers to continue breastfeeding on return to�work, the health benefits of breastfeeding for mums, the legislation affecting mothers at�work, and some easy steps that employers can take to support breastfeeding mothers.

GLUT2 surface expression and intracellular transport via the constitutive pathway in pancreatic beta cells and insulinoma: evidence for a block in trans-Golgi network exit by brefeldin A.

The biosynthesis, intracellular transport, and surface expression of the beta cell glucose transporter GLUT2 was investigated in isolated islets and insulinoma cells. Using a trypsin sensitivity assay to measure cell surface expression, we determined that: (a) greater than 95% of GLUT2 was expressed on the plasma membrane; (b) GLUT2 did not recycle in intracellular vesicles; and (c) after trypsin treatment, reexpression of the intact transporter occurred with a t1/2 of approximately 7 h. Kinetics of intracellular transport of GLUT2 was investigated in pulse-labeling experiments combined with glycosidase treatment and the trypsin sensitivity assay. We determined that transport from the endoplasmic reticulum to the trans-Golgi network (TGN) occurred with a t1/2 of 15 min and that transport from the TGN to the plasma membrane required a similar half-time. When added at the start of a pulse-labeling experiment, brefeldin A prevented exit of GLUT2 from the endoplasmic reticulum. When the transporter was first accumulated in the TGN during a 15-min period of chase, but not following a low temperature (22 degrees C) incubation, addition of brefeldin A (BFA) prevented subsequent surface expression of the transporter. This indicated that brefeldin A prevented GLUT2 exit from the TGN by acting at a site proximal to the 22 degrees C block. Together, these data demonstrate that GLUT2 surface expression in beta cells is via the constitutive pathway, that transport can be blocked by BFA at two distinct steps and that once on the surface, GLUT2 does not recycle in intracellular vesicles.

Does the mechanical work in running change during the VO2 slow component?

PURPOSE: The origin of the slow component is not fully understood. The mechanical hypothesis is one of the potential factors, because an increase in external mechanical work with fatigue was previously reported for a constant velocity run. The purpose of this study was to determine whether a change in mechanical work could occur during the development of the VO2 slow component under the effect of fatigue. METHODS: Twelve regional-level competitive runners performed a square-wave transition, corresponding to 95% of the speed associated with peak VO2 obtained during an incremental test. The VO2 response was fit with a classical model including two exponential functions. A specific treadmill with three-dimensional force transducers was used to measure the ground reaction force. Kinetic work (W(kin)), potential work (W(pot)), external work (W(ext)), and an index of internal work (W(int)) per unit of distance were quantified continuously. RESULTS: During the slow component of VO2, a significant increase in W (P< 0.01), no change in W, and a significant decrease in W and W index (P< 0.05, P< 0.001, respectively) were observed. CONCLUSION: The present study showed that the slow component of VO2 did not result partly from a change in mechanical work under the effect of fatigue. Nevertheless, the decrease in stride frequency (P< 0.001) and contact time (P< 0.001) suggested an alternative mechanical explanation. The slow component during running may be due to the cost of generating force or to alterations in the storage and recoil of elastic energy, and not to the external mechanical work.

(.)VO(2) and EMG activity kinetics during moderate and severe constant work rate exercise in trained cyclists.

The purpose of this study was to compare O(2) uptake ((.)VO(2)) and muscle electromyography activity kinetics during moderate and severe exercise to test the hypothesis of progressive recruitment of fast-twitch fibers in the explanation of the VO(2) slow component. After an incremental test to exhaustion, 7 trained cyclists (mean +/- SD, 61.4 +/- 4.2 ml x min(-1) x kg(- 1)) performed several square-wave transitions for 6 min at moderate and severe intensities on a bicycle ergometer. The (.)VO(2) response and the electrical activity (i.e., median power frequency, MDF) of the quadriceps vastus lateralis and vastus medialis of both lower limbs were measured continuously during exercise. After 2 to 3 min of exercise onset, MDF values increased similarly during moderate and severe exercise for almost all muscles whereas a (.)VO(2) slow component occurred during severe exercise. There was no relationship between the increase of MDF values and the magnitude of the (.)VO(2) slow component during the severe exercise. These results suggest that the origin of the slow component may not be due to the progressive recruitment of fast-twitch fibers.

The bladder wall under extreme stress condition: ultrastructural observations in a hibernating mammal.

Comparative ultrastructural observations are presented of the distended bladder of a hibernating dormouse (Muscardinus avellanarius) and a relaxed organ taken from an active animal. The distended bladder of the hibernating animal has an extremely thin wall lined with a three-layer urothelium. An osmiophilic coat lines the luminal surface of the urothelium in the hibernating animal, but it is very thin indeed in the specimen from the active dormouse. In the urothelium of the distended bladder, a larger number of fusiform vesicles (FVs, typical structures of the urothelium with asymmetric unit membrane) is found. On the contrary, lysosomes, multivesicular bodies, and interdigitation of plasma membrane between adjacent cells are all more frequent in the relaxed bladder of the active dormouse. Results suggest that hibernating animals can be a useful model for investigating the biology of epithelial cells in the mammalian bladder.

Isolated congenital atrioventricular block diagnosed in utero: natural history and outcome.

BACKGROUND: Isolated congenital atrioventricular block (CAVB) diagnosed in utero is associated with a high morbidity and mortality. Prognosis is especially poor when heart rate drops below 55 beats per minute (bpm) and when fetal hydrops develops. We describe the natural history and outcome of 24 infants with isolated CAVB diagnosed in utero, review the literature, and assess the risk factors that could predict outcome. METHODS: This was a retrospective multicenter study of 24 patients with isolated CAVB diagnosed in utero. RESULTS: CAVB was detected at a mean gestational age (GA) of 24.7 +/- 5.1 weeks. Ten fetuses initially presented with complete heart block. Low heart rate or incomplete heart block was the first documentation of bradyarrhythmia in the other 14 fetuses. In 11 of them, CAVB developed during pregnancy after a median time of 3 (range 1-16) weeks. Fetal hydrops developed in 10 of 24 (42%) fetuses at a mean GA of 27.6 +/- 5.1 weeks. Hydropic fetuses showed lower heart rates during pregnancy (47 +/- 10 bpm) than non-hydropic fetuses (57 +/- 10 bpm). There were three intrauterine deaths; all were hydropic and female. Nine viable females and 12 males were born at a mean GA of 37.1 +/- 6.1 weeks with an average birth weight of 3097 +/- 852 g. Fifteen CAVB patients required pacemaker (PM) intervention, 10 of them immediately after birth. Dilated cardiomyopathy (DCM) developed in three infants of whom two died of congestive heart failure, shortly after the diagnosis was made; one is still alive. Mortality before or after birth was 21%, and was associated with heart rates below 50 bpm and development of fetal hydrops. Poor outcome, defined as death, PM implantation, or development of DCM, occurred in 83% of cases and was associated with heart rates below 60 bpm during pregnancy. CONCLUSIONS: Isolated CAVB diagnosed in utero is associated with high morbidity and mortality. Patients who develop fetal hydrops show lower heart rates during pregnancy than patients who do not. A fetal heart rate below 50 bpm and development of fetal hydrops is associated with increased mortality. Rates below 60 bpm are associated with PM requirement and/or DCM.

Oocyst wall formation and composition in coccidian parasites

The oocyst wall of coccidian parasites is a robust structure that is resistant to a variety of environmental and chemical insults. This resilience allows oocysts to survive for long periods, facilitating transmission from host to host. The wall is bilayered and is formed by the sequential release of the contents of two specialized organelles - wall forming body 1 and wall forming body 2 - found in the macrogametocyte stage of Coccidia. The oocyst wall is over 90% protein but few of these proteins have been studied. One group is cysteine-rich and may be presumed to crosslink via disulphide bridges, though this is yet to be investigated. Another group of wall proteins is rich in tyrosine. These proteins, which range in size from 8-31 kDa, are derived from larger precursors of 56 and 82 kDa found in the wall forming bodies. Proteases may catalyze processing of the precursors into tyrosine-rich peptides, which are then oxidatively crosslinked in a reaction catalyzed by peroxidases. In support of this hypothesis, the oocyst wall has high levels of dityrosine bonds. These dityrosine crosslinked proteins may provide a structural matrix for assembly of the oocyst wall and contribute to its resilience.

The interaction between Histoplasma capsulatum cell wall carbohydrates and host components: relevance in the immunomodulatory role of histoplasmosis

Histoplasma capsulatum is an intracellular fungal pathogen that causes respiratory and systemic disease by proliferating within phagocytic cells. The binding of H. capsulatum to phagocytes may be mediated by the pathogen's cell wall carbohydrates, glucans, which consist of glucose homo and hetero-polymers and whose glycosydic linkage types differ between the yeast and mycelial phases. The ±-1,3-glucan is considered relevant for H. capsulatum virulence, whereas the ²-1,3-glucan is antigenic and participates in the modulation of the host immune response. H. capsulatum cell wall components with lectin-like activity seem to interact with the host cell surface, while host membrane lectin-like receptors can recognize a particular fungal carbohydrate ligand. This review emphasizes the relevance of the main H. capsulatum and host carbohydrate-driven interactions that allow for binding and internalization of the fungal cell into phagocytes and its subsequent avoidance of intracellular elimination.

Sulfur isotope analysis of cinnabar from Roman wall paintings by elemental analysis/isotope ratio mass spectrometry - tracking the origin of archaeological red pigments and their authenticity

The most valuable pigment of the Roman wall paintings was the red color obtained from powdered cinnabar (Minium Cinnabaris pigment), the red mercury sulfide (HgS), which was brought from mercury (Hg) deposits in the Roman Empire. To address the question of whether sulfur isotope signatures can serve as a rapid method to establish the provenance of the red pigment in Roman frescoes, we have measured the sulfur isotope composition (delta(34) S value in parts per thousand VCDT) in samples of wall painting from the Roman city Aventicum (Avenches, Vaud, Switzerland) and compared them with values from cinnabar from European mercury deposits (Almaden in Spain, Idria in Slovenia, Monte Amiata in Italy, Moschellandsberg in Germany, and Genepy in France). Our study shows that the delta(34) S values of cinnabar from the studied Roman wall paintings fall within or near to the composition of Almaden cinnabar; thus, the provenance of the raw material may be deduced. This approach may provide information on provenance and authenticity in archaeological, restoration and forensic studies of Roman and Greek frescoes. Copyright (c) 2010 John Wiley & Sons, Ltd.

Work Meaningfulness as a Key Enhancer of Ethical Values in Business

Despite abundant research on work meaningfulness, the link between work meaningfulness and general ethical attitude at work has not been discussed so far. In this article, we propose a theoretical framework to explain how work meaningfulness contributes to enhanced ethical behavior. We argue that by providing a way for individuals to relate work to one's personal core values and identity, work meaningfulness leads to affective commitment - the involvement of one's cognitive, emotional, and physical resources. This, in turn, leads to engagement and so facilitates the integration of one's personal values in the daily work routines, and so reduces the risk of unethical behavior. On the contrary, anomie, that is, the absence of meaning and consequently of personal involvement, will lead to lower rational commitment rather than affective commitment, and consequently to disengagement and a-morality. We conclude with implications for the management of ethical attitudes.

Molecular dissection of Arabidopsis thaliana endodermis development, structure and function

In vascular plants, the endodermis establishes a protective diffusion barrier surrounding the vasculature preventing the passive, uncontrolled entry of nutrients absorbed by the plant. It does so by means of a differentiation feature, the "Casparian Strip" (CS), a highly localized cell wall impregnation made of lignin, which seals the extracellular space. Although the existence of this differentiation feature has been intensively described, the mechanisms establishing this hallmark remain obscure. In this work I report, the developmental sequence of events that leads to a differentiated endodermis, in the plant model Arabidopsis thaliana. In addition, my descriptive approach gave important insights as to how these cells define membrane domains involved in the directional transport of nutrients. I also participated in characterizing a new transmembrane protein family, the CASPs, localized to the membrane domain underlying the CS, which we accordingly named the Casparian Strip membrane Domain (CSD). Our molecular analysis indicates that these proteins drive CS establishment. To identify more molecular factors of CS establishment, I performed a forward genetic screen. This screen led to the identification of 11 endodermis permissive mutants, which we named schengen (sgn) mutants. The causative mutations have been mapped to 5 independent loci: SGN1 to SGN5. SGN1 and SGN3 encode Receptor Like Kinases involved in the correct establishment of the CSD. A lack of those kinases leads to an incomplete CSD, which gives rise to interrupted CS barriers. Interestingly, SGN1 seems to also regulate CSD positioning to the middle of endodermal transversal walls. SGN4 encodes an NADPH oxidase involved in lignin polymerization essential for CS formation. The sgn5 mutant induces extra divisions of cortical cells strongly affecting the cell identity, but also leading to incorrect differentiation. A thorough characterization of the sgn2 mutant will follow elsewhere, yet preliminary results indicate that SGN2 encodes an Acyl-CoA N-acyltransferase. . In summary, with my work I have contributed a first set of molecular players of Casparian strip formation and initiated their characterization. Eventually, this might lead to an understanding of the molecular mechanisms of CS establishment in A.thaliana . This in turn will hopefully help to better understand nutrient uptake in higher plants and their response to environmental stresses. - Au sein des plantes vasculaires, l'endoderme représente un tissu protecteur mettant en place une barrière imperméable, empêchant n'importe quel élément de rejoindre les tissus conducteurs par simple diffusion. Cette barrière, appelée « Cadre de Caspary », correspond à une lignification de la paroi de l'endoderme et donne lieu à un cloisonnement de l'espace intercellulaire. Bien que cet élément de différenciation soit décrit en détail, sa mise en place reste incomprise. Cette étude indique la suite d'événements aboutissant à l'établissement du cadre de Caspary chez la plante modèle Arabidopsis thaliana. De plus, ce travail apporte de nouvelles connaissances expliquant comment ces cellules définissent des domaines membranaires importants pour le transport des nutriments. Nous décrivons une nouvelle famille de protéines membranaires, les CASPs (« CAparian Strip membrane domain Proteins »), localisées dans un domaine membranaire longeant le cadre de Caspary : le domaine de Caspary (CSD). L'analyse moléculaire des CASPs indique qu'elles dirigent la formation du cadre de Caspary. Par ailleurs, une approche génétique directe nous a permis d'identifier 11 mutants ayant un endoderme perméable. Nous avons nommé ces mutants Schengen, en référence à la zone de libre échange européenne. Les mutations impliquées dans ces mutants affectent 5 gènes désignés de SGN1 à SGN5. SGN1 et SGN3 produisent des protéines de type kinases (« Receptor-like Kinases », RLK) qui participent à la délimitation du CSD. L'absence de ces kinases aboutit à un domaine CSD incomplet, se traduisant par un cadre de Caspary discontinu. De plus, SGN1 semble réguler le positionnement du CSD au milieu de la paroi transversale de l'endoderme. SGN4 produit une enzyme de type NADPH oxydase impliquée dans la polymérisation du cadre de Caspary. Dans le mutant sgn5, on observe une division anormale des cellules du cortex créant ainsi une nouvelle couche cellulaire incapable d'achever sa différenciation en endoderme. Quant à la mutation sgn2, bien que nous pensons qu'elle affecte une Acyl-CoA N-acyltransferase, sa caractérisation ne sera réalisée que prochainement. Au final, ce travail procure de nouveaux éléments sur l'établissement du cadre de Caspary qui pourraient être importants afin de comprendre comment les plantes sélectionnent leurs nutriments et résistent à des conditions environnementales parfois hostiles. - De par leur immobilité, les plantes terrestres n'ont pas d'autre choix que de puiser leurs ressources dans leur environnement direct. La plante extrait du sol les nutriments qui lui sont nécessaires et les redistribue grâce à des tissus conducteurs. Afin de ne pas s'intoxiquer, il est donc essentiel de pouvoir sélectionner les éléments entrant dans la racine. Etonnement, ce n'est pas la surface des racines qui permet ce contrôle mais un tissu interne appelé endoderme. Ce dernier forme une barrière imperméable qui entoure chaque cellule et crée une jointure permettant de bloquer le passage des éléments entre les cellules. Cette structure, appelée « cadre de Caspary », oblige les éléments à entrer dans les cellules de l'endoderme et à être ainsi sélectionnés. Bien que cette structure soit décrite en détail, sa mise en place reste incomprise. Cette étude indique la suite d'événements qui aboutit à la formation du cadre de Caspary chez la plante modèle Arabidopsis thaliana. Ce travail apporte également de nouvelles connaissances expliquant comment ces cellules définissent, organisent et dirigent le transport des nutriments. Nous décrivons comment certains éléments de la cellule, les protéines CASPs (CAsparian Strip membrane domain Proteins), sont organisées un domaine particulier des membranes afin de créer une plateforme de construction longeant le cadre de Caspary : le domaine de Caspary (CSD). Afin de déterminer ce qu'il se passerait si une plante ne possédait pas de cadre de Caspary, nous avons réalisé une mutagénèse, ou approche génétique directe, et identifié 11 mutants (individu ayant un gène défectueux conduisant à la perte d'une fonction) ayant un endoderme perméable. Nous avons nommé ces mutants schengen, en référence à la zone de libre échange européenne. Les mutations impliquées dans ces mutants affectent 5 gènes désignés de SGN1 à SGN5. Les gènes SGN1 et SGN3 produisent des protéines de type kinases (« Receptor-like Kinases », RLK) servant à l'établissement de la plateforme de construction. L'absence de ces kinases aboutit à une base incomplète, se traduisant par un cadre de Caspary discontinu. Qui plus est, la kinase SGN1 semble réguler le positionnement de la plateforme au milieu de l'endoderme. Le gène SGN4 est par contre, impliqué dans la construction à proprement dite du cadre de Caspary. Dans le mutant sgn5, on observe une nouvelle couche de cellules ressemblant à de l'endoderme mais incapable de former correctement une barrière identique au cadre de Caspary. Quant au dernier mutant, sgn2, bien que cette étude fournisse des indices permettant de comprendre pourquoi le mutant sgn2 est défectueux, nous n'expliquerons ce cas que prochainement. En résumé, ce travail procure de nouvelles connaissances sur l'établissement du cadre de Caspary qui pourraient être importantes afin de comprendre comment les plantes sélectionnent leurs nutriments et résistent à des conditions environnementales parfois hostiles.

Dam wall detection and tracking using a Mechanically Scanned Imaging Sonar

In dam inspection tasks, an underwater robot has to grab images while surveying the wall meanwhile maintaining a certain distance and relative orientation. This paper proposes the use of an MSIS (mechanically scanned imaging sonar) for relative positioning of a robot with respect to the wall. An imaging sonar gathers polar image scans from which depth images (range & bearing) are generated. Depth scans are first processed to extract a line corresponding to the wall (with the Hough transform), which is then tracked by means of an EKF (Extended Kalman Filter) using a static motion model and an implicit measurement equation associating the sensed points to the candidate line. The line estimate is referenced to the robot fixed frame and represented in polar coordinates (rho&thetas) which directly corresponds to the actual distance and relative orientation of the robot with respect to the wall. The proposed system has been tested in simulation as well as in water tank conditions