703 research outputs found
Analysis of tissue surrounding thyroid nodules by ultrasound digital images
Since US is not easily reproducible, the digital image analysis (IA) has been proposed so that the image evaluation is not subjective. In fact, IA meets the criteria of objectivity, accurateness, and reproducibility by a matrix of pixels whose value is displayed in a gray level. This study aims at evaluating via IA the tissue surrounding a thyroid nodule (backyard tissue, BT) from goitres with benign (b-BT) and malignant (m-BT) lesions. Sixty-nine US images of thyroid nodules surrounded by adequate thyroid tissue was classified as normoechoic and homogeneous were enrolled as study group. Forty-three US images from normal thyroid (NT) glands were included as controls. Digital images of 800 à 652 pixels were acquired at a resolution of eight bits with a 256 gray levels depth. By one-way ANOVA, the 43 NT glands were not statistically different (P = 0.91). Mean gray level of normal glands was significantly higher than b-BT (P = 0.026), and m-BT (P = 0.0001), while no difference was found between b-BT and m-BT (P = 0.321). NT tissue boundary external to the nodule was found at 6.0 ± 0.5 mm in cancers and 4.0 ± 0.5 mm in benignancies (P = 0.001). These data should indicate that the tissue surrounding a thyroid nodule may be damaged even when assessed as normal by US. This is of interest to investigate the extranodular effects of thyroid tumors
Hair cell maturation is differentially regulated along the tonotopic axis of the mammalian cochlea
Sound amplification within the mammalian cochlea depends upon specialized hair cells, the outer hair cells (OHCs), which possess both sensory and motile capabilities. In various altricial rodents, OHCs become functionally competent from around postnatal day 7 (P7), before the primary sensory inner hair cells (IHCs), which become competent at about the onset of hearing (P12). The mechanisms responsible for the maturation of OHCs and their synaptic specialization remain poorly understood. We report that spontaneous Ca2+ activity in the immature cochlea, which is generated by CaV1.3 Ca2+ channels, differentially regulates the maturation of hair cells along the cochlea. Under nearâphysiological recording conditions we found that, similar to IHCs, immature OHCs elicited spontaneous Ca2+ action potentials (APs), but only during the first few postnatal days. Genetic ablation of these APs in vivo, using CaV1.3â/â mice, prevented the normal developmental acquisition of matureâlike basolateral membrane currents in lowâfrequency (apical) hair cells, such as IK,n (carried by KCNQ4 channels), ISK2 and IACh (α9α10nAChRs) in OHCs and IK,n and IK,f (BK channels) in IHCs. Electromotility and prestin expression in OHCs were normal in CaV1.3â/â mice. The maturation of highâfrequency (basal) hair cells was also affected in CaV1.3â/â mice, but to a much lesser extent than apical cells. However, a characteristic feature in CaV1.3â/â mice was the reduced hair cell size irrespective of their cochlear location. We conclude that the development of lowâ and highâfrequency hair cells is differentially regulated during development, with apical cells being more strongly dependent on experienceâindependent Ca2+ APs
A primer on the welfare eects of regulatory reforms in network industries
Starting from an industry where production is provided by a public monopolist, we look at the effects on the consumers\u2019 surplus of a sequence of reforms in network industry. Using a simple comparative statics framework, we find indifference conditions in consumers\u2019 surplus between respectively public monopoly, unregulated private monopoly, regulated private monopoly, vertically disintegrated monopoly, duopoly and liberalized market. The results are determined by the relative size of the x-inefficiencies of the public monopolist, allocative inefficiencies of private monopoly, the cost of unbundling and costs related to establishing a competitive market
Nearby Optical Galaxies: Selection of the Sample and Identification of Groups
In this paper we describe the Nearby Optical Galaxy (NOG) sample, which is a complete, distance-limited (6000 km/s) and magnitude-limited (B14) sample of 7000 optical galaxies. The sample covers 2/3 (8.27 sr) of the sky () and appears to have a good completeness in redshift (98%). We select the sample on the basis of homogenized corrected total blue magnitudes in order to minimize systematic effects in galaxy sampling. We identify the groups in this sample by means of both the hierarchical and the percolation {\it friends of friends} methods. The resulting catalogs of loose groups appear to be similar and are among the largest catalogs of groups presently available. Most of the NOG galaxies (60%) are found to be members of galaxy pairs (580 pairs for a total of 15% of objects) or groups with at least three members (500 groups for a total of 45% of objects). About 40% of galaxies are left ungrouped (field galaxies). We illustrate the main features of the NOG galaxy distribution. Compared to previous optical and IRAS galaxy samples, the NOG provides a denser sampling of the galaxy distribution in the nearby universe. Given its large sky coverage, the identification of groups, and its high-density sampling, the NOG is suited for the analysis of the galaxy density field of the nearby universe, especially on small scales
DEVELOPMENT AND VALIDATION OF A PET RADIOMICSÂ PROGNOSTIC MODEL FOR DIFFUSE LARGE B CELLÂ LYMPHOMA
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Coordinated calcium signalling in cochlear sensory and nonâsensory cells refines afferent innervation of outer hair cells
Outer hair cells (OHCs) are highly specialized sensory cells conferring the fineâtuning and high sensitivity of the mammalian cochlea to acoustic stimuli. Here, by genetically manipulating spontaneous Ca2+ signalling in mice in vivo, through a period of early postnatal development, we find that the refinement of OHC afferent innervation is regulated by complementary spontaneous Ca2+ signals originating in OHCs and nonâsensory cells. OHCs fire spontaneous Ca2+ action potentials during a narrow period of neonatal development. Simultaneously, waves of Ca2+ activity in the nonâsensory cells of the greater epithelial ridge cause, via ATPâinduced activation of P2X3 receptors, the increase and synchronization of the Ca2+ activity in nearby OHCs. This synchronization is required for the refinement of their immature afferent innervation. In the absence of connexin channels, Ca2+ waves are impaired, leading to a reduction in the number of ribbon synapses and afferent fibres on OHCs. We propose that the correct maturation of the afferent connectivity of OHCs requires experienceâindependent Ca2+ signals from sensory and nonâsensory cells
Strategies for implementing placental transfusion at birth: a systematic review
Background: Enhanced placental transfusion reduces adverse neonatal outcomes, including death. Despite being endorsed by the World Health Organization in 2012, the method has not been adopted widely in practice.
Methods: We performed a systematic literature search and included quality improvement projects on placental transfusion at birth and studies on barriers to implementation. We extracted information on population, methods of implementation, obstacles to implementation, and strategies to overcome them.
Results: We screened 99 studies out of which 18 were included in the review. The preferred methods of implementation were protocol development (86% of studies) reinforced by targeted education (64% of studies) and multidisciplinary team involvement (43% of studies). Barriers to implementation were mentioned in 12 studies and divided into four categories: general factors such as lack of staff awareness (5 studies) and professional resistance to change (5 studies); obstetricianâspecific concerns, including the impact during cesarean (3 studies) and the risk of postpartum hemorrhage (3 studies); pediatricianâspecific concerns, including the need for resuscitation (5 studies), risk of jaundice (3 studies), and polycythemia (2 studies); and logistical difficulties. The main strategies to facilitate placental transfusion at birth included effective multidisciplinary team collaboration, protocol development, targeted education, and constructive feedback sessions.
Conclusions: Placental transfusion implementation requires a multidisciplinary approach, with obstetricians, midwives, nurses, and pediatricians central to adoption of the practice. Understanding the obstacles to implementation informs strategies to increase placental transfusion adoption of practice worldwide. We suggest a stepwise approach to implementation and enhancement of placental transfusion into practice
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