230 research outputs found
Lack of Spontaneous Venous Pulsation: Possible Risk Indicator in Normal Tension Glaucoma?
PURPOSE: Recently, the absence of spontaneous venous pulsation (SVP) has been suggested as a vascular risk factor for primary open-angle glaucoma (POAG). As the mechanism behind this phenomenon is still unknown, the authors have studied this vascular component using colour Doppler imaging (CDI).
METHODS:
A total of 236 patients were divided into three diagnostic groups: healthy controls (81), POAG (86) and normal tension glaucoma (NTG; 69). All subjects were submitted to CDI studies of the retrobulbar circulation, intraocular pressure measurements and assessment of SVP existence. Mann-Whitney, chi-square contingency tables and Spearman correlations were used to explore differences and correlations between variables in the diagnostic groups.
RESULTS:
Eighty-two percent of healthy controls had SVP (66/81), while a smaller numbers were registered in both glaucoma groups: POAG - 50% (43/86); NTG - 51% (35/69). In NTG patients, but not in POAG patients, the prevalence of the SVP phenomenon decreases with increased glaucoma damage (p = 0.04; p = 0.55, respectively). Overall glaucoma patients from both groups had lower central retinal vein (CRV) velocities than the healthy controls (p < 0.05). NTG patients with SVP had less severe visual field defects (mean defect -6.92 versus -11.1, p < 0.05), higher [correction added after online publication 21 September 2012; the word 'higher' has been inserted to replace the word 'lower'] peak systolic and mean flow velocities in the central retinal artery (p < 0.01; p < 0.05, respectively) as well as higher [correction added after online publication 21 September 2012; the word higher has been inserted to replace the word lower] maximal velocities and RI of the CRV (p < 0.02; p < 0.05, respectively).
CONCLUSIONS:
Glaucoma patients have a decrease in CRV velocities. SVP is less prevalent in glaucoma patients than in healthy individuals. This phenomenon apparently reflects different hemodynamic patterns in the central retinal vessels. This variable may be of particular importance in NTG patients, where it may be associated with more advanced functional damage
Ophthalmic Artery Doppler Waveform Changes Associated with Increased Damage in Glaucoma Patients
PURPOSE: To characterize Doppler waveform variables (early systolic acceleration [ESA] and systolic/diastolic mean velocity ratios [Sm/Dm]) of the Ophthalmic Artery (OA) by color Doppler imaging (CDI) in eyes with primary open-angle glaucoma (POAG).
METHODS:
Analysis of CDI examinations of the retrobulbar circulation of patients with POAG (n = 102), normal tension glaucoma (NTG, n = 89), and healthy controls (n = 59) by a condition-masked investigator. One-way ANOVA, chi-square, and Spearman's rank correlation tests were used to determine differences, establish comparisons, and to explore associations between variables, respectively.
RESULTS:
The overall Doppler waveform presented a shift to the right in the glaucoma groups, with significantly lower Sm/Dm ratios when compared to the control group (healthy: 2.94 ± 0.86, POAG: 2.60 ± 0.67, NTG: 2.63 ± 0.84; P = 0.01). ESA was significantly lower in the glaucoma groups (healthy: 688.8 ± 484 cm·s(-2), POAG: 548.1 ± 419 cm·s(-2), NTG: 548.5 ± 337 cm·s(-2); P = 0.03). No statistical differences were, however, detected in the OA velocities or resistance index (P ranged between 0.08 and 0.96). In the glaucoma groups, waveform parameters such as ESA, acceleration time, and systolic mean velocities correlated with systemic blood pressure variables (P < 0.05). In these groups, negative correlations were detected between Sm/Dm ratios and the degree of visual field defects (POAG: P = 0.01; r = -0.25) and retinal nerve fiber layer thickness (NTG: P = 0.02; r = -0.25).
CONCLUSIONS:
The pattern of blood flow velocities in the OA throughout the cardiac cycle seems to be altered in glaucoma patients. Further studies on how systemic blood pressure affects waveform variables in glaucoma patients may provide a better understanding of an underlying vascular dysfunction
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Asymmetries in speech articulation as reflected on palatograms: a meta-study
This paper presents the results from an investigation of asymmetries in speech articulation on the basis of 1,502 previously published palatograms of a wide variety of speech sounds in a range of languages. For each palatogram, the direction and degree of tongue-palate contact was quantified by means of an index capturing the degree of lateral asymmetry. The results of this investigation show that lingual asymmetry in the articulation of speech sounds is substantial: 83% of the palatograms are asymmetrical. With respect to the direction of the asymmetry it is found that the asymmetry is more often towards the left side of the palate (45%) than to the right side (38%). Further analysis reveals that there are significant differences in both the direction and the degree of the asymmetry as a function of manner and place of articulation
A Citizens Compact: Reaching out to the Citizens of Europe. CEPS EPIN Working Papers No. 14, 1 September 2005
[Executive Summary]. How can the deadlock after the ‘no’ to the European Constitutional Treaty in France and the Netherlands be overcome? What should be the aim of the ‘period of reflection’ that has been agreed by the European Council? The authors of this paper propose the adoption of a ‘Citizens Compact’, which should directly address the larger malaise among citizens that underlies the Constitutional crisis. It should contribute to the reduction of the EU’s democratic deficit without treaty reform. The following measures should be envisaged: • National parliaments should participate more strongly in the controversies on core European issues through earlier and intensive debates about EU initiatives. • Every six months governments should explain their positions on the priorities of the EU-presidency in their national parliaments. • EU-actors (MEPs, Commissioners and top officials) should participate more intensively in national debates about European issues and contribute to a better understanding of the European political processes among citizens. • National governments should regularly publish information bulletins about the latest EU initiatives and –decisions. • Public fora about European issues should be established in every member state with speakers coming from national politics, from the EU level and other member states as well as representatives from civil society. • Uncontroversial elements of the Constitutional Treaty that strengthen EU democracy could already be adopted through inter-institutional agreements. • A White Paper on the establishment of a ‘European Democratic and Civic Space’ in the EU should be elaborated. • In the future important legislative acts should contain an impact assessment of the consequences on citizens’ lives
New records and observations of macroalgae and associated pathogens from the Falkland Islands, Patagonia and Tierra del Fuego
Subantarctic and Antarctic regions remain little explored with regards to their seaweed diversity. This study is based upon collections in the early 1970s and 2007–2013. It is supported by sequencing COI (mitochondrial cytochrome oxidase I) and reports new records for four species of brown algae Hincksia granulosa, Hincksia sandriana, Myriotrichia clavaeformis, Syringoderma australe), four red algae (Erythrotrichia carnea, Paraglossum salicifolium, Phycodrys antarctica, Plumariopsis eatonii), one green alga (Chaetomorpha aerea) and of the oomycete Anisolpidium ectocarpii. A further four brown algae are reported at genus level and discussed (Cladostephus sp., Colpomenia sp., Dictyota sp., Punctaria sp.). Observations of the biology of three brown algal taxa (Cladothele decaisnei, Geminocarpus geminatus, Halopteris obovata) from the region are also reported here
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Listeners' perception of lexical stress in the first words of infants with cochlear implants and normally hearing infants
Normally hearing (NH) infants are able to produce lexical stress in their first words, but congenitally hearing-impaired childrenwith cochlear implants (CI) may find this more challenging,given the limited transmission of spectro-temporal information by the implant. Acoustic research has shownthat the acoustic cues to stressin the first words of Dutch-acquiring CI infants are less pronounced (Pettinato et al. 2017). The present study investigate show listeners perceive lexical stress in the first words of CI and NH infants.Two research questions are addressed: (1) How successful are CI and NH children in implementing the prosodic cues to prominence? (2) Is the degree of stress in CI and NHwords perceived to be similar? The stimuli used in this study are disyllabic words (n = 1089) produced by 9 infants with CI and 9 NH infants acquiring Dutch. The words were presented to adult listenersin a listening experiment,in which they assessed the stress pattern on a continuous visual analogue scale (VAS) which expresses to what extent syllables are perceived as stressed.The results show that listeners perceive typical word stress production in the first words of infants with CI. The words of CI and NH infants were rated in agreement with the target stress pattern as often,and trochaic words were rated more frequently as such than iambic words. Listeners more frequently perceive unstressed syllables inthe first words of infants with CI. However, for the words that are perceived to be clearly stressed, the degree of word stress is comparable in the two groups,and both infant groups are perceived to produce more contrast between stressed and unstressed syllables in trochees than in iambs. It is concluded that that acoustic differences between CI and NH infants’ stress production are not necessarily perceptually salient
Silver nanoparticle-coated polyhydroxyalkanoate based electrospun fibers for wound dressing applications
Wound dressings are high performance and high value products which can improve the regeneration of damaged skin. In these products, bioresorption and biocompatibility play a key role. The aim of this study is to provide progress in this area via nanofabrication and antimicrobial natural materials. Polyhydroxyalkanoates (PHAs) are a bio-based family of polymers that possess high biocompatibility and skin regenerative properties. In this study, a blend of poly(3-hydroxybutyrate) (P(3HB)) and poly(3-hydroxyoctanoate-co-3-hydroxy decanoate) (P(3HO-co-3HD)) was electrospun into P(3HB))/P(3HO-co-3HD) nanofibers to obtain materials with a high surface area and good han-dling performance. The nanofibers were then modified with silver nanoparticles (AgNPs) via the dip-coating method. The silver-containing nanofiber meshes showed good cytocompatibility and interesting immunomodulatory properties in vitro, together with the capability of stimulating the human beta defensin 2 and cytokeratin expression in human keratinocytes (HaCaT cells), which makes them promising materials for wound dressing applications
Electrosprayed chitin nanofibril/electrospun polyhydroxyalkanoate fiber mesh as functional nonwoven for skin application
Polyhydroxyalkanoates (PHAs) are a family of bio-based polyesters that have found different biomedical applications. Chitin and lignin, byproducts of fishery and plant biomass, show antimicrobial and anti-inflammatory activity on the nanoscale. Due to their polarities, chitin nanofibril (CN) and nanolignin (NL) can be assembled into micro-complexes, which can be loaded with bioactive factors, such as the glycyrrhetinic acid (GA) and CN-NL/GA (CLA) complexes, and can be used to decorate polymer surfaces. This study aims to develop completely bio-based and bioactive meshes intended for wound healing. Poly(3-hydroxybutyrate)/ Poly(3-hydroxyoctanoate-co-3-hydroxydecanoate), P(3HB)/P(3HO-co-3HD) was used to produce films and fiber meshes, to be surface-modified via electrospraying of CN or CLA to reach a uniform distribution. P(3HB)/P(3HO-co-3HD) fibers with desirable size and morphology were successfully prepared and functionalized with CN and CLA using electrospinning and tested in vitro with human keratinocytes. The presence of CN and CLA improved the indirect antimicrobial and anti-inflammatory activity of the electrospun fiber meshes by downregulating the expression of the most important pro-inflammatory cytokines and upregulating human defensin 2 expression. This natural and eco-sustainable mesh is promising in wound healing applications
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Prosodic modulation in the babble of cochlear implanted and normally hearing infants: a perceptual study using a visual analogue scale
This study investigates prosodic modulation in the spontaneous canonical babble of congenitally deaf infants with cochlear implants (CI) and normally hearing (NH) infants. Research has shown that the acoustic cues to prominence are less modulated in CI babble. However acoustic measurements of individual cues to prominence give incomplete information about prosodic modulation. In the present study, raters are asked to judge prominence since they simultaneously take into account all prosodic cues. Disyllabic utterances produced by CI and NH infants were presented to naive adult raters who had to indicate the degree and direction of prosodic modulation between syllables on a visual analogue scale. The results show that the babble of infants with CI is rated as having less prosodic modulation. Moreover, segmentally more variegated babble is rated as having more prosodic modulation. Raters do not perceive the babble to be predominantly trochaic, which indicates that the predominant stress pattern of Dutch is not yet apparent in the children’s productions
Photonic realization of the relativistic Kronig-Penney model and relativistic Tamm surface states
Photonic analogues of the relativistic Kronig-Penney model and of
relativistic surface Tamm states are proposed for light propagation in fibre
Bragg gratings (FBGs) with phase defects. A periodic sequence of phase slips in
the FBG realizes the relativistic Kronig-Penney model, the band structure of
which being mapped into the spectral response of the FBG. For the semi-infinite
FBG Tamm surface states can appear and can be visualized as narrow resonance
peaks in the transmission spectrum of the grating
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