996 resultados para Potential fluctuations


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Permanent hearing loss is a leading global health care burden, with 1 in 10 people affected to a mild or greater degree. A shortage of trained healthcare professionals and associated infrastructure and resource limitations mean that hearing health services are unavailable to the majority of the world population. Utilizing information and communication technology in hearing health care, or tele-audiology, combined with automation offer unique opportunities for improved clinical care, widespread access to services, and more cost-effective and sustainable hearing health care. Tele-audiology demonstrates significant potential in areas such as education and training of hearing health care professionals, paraprofessionals, parents, and adults with hearing disorders; screening for auditory disorders; diagnosis of hearing loss; and intervention services. Global connectivity is rapidly growing with increasingly widespread distribution into underserved communities where audiological services may be facilitated through telehealth models. Although many questions related to aspects such as quality control, licensure, jurisdictional responsibility, certification and reimbursement still need to be addressed; no alternative strategy can currently offer the same potential reach for impacting the global burden of hearing loss in the near and foreseeable future.

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The objective of this study was to evaluate bone formation after application of different doses of recombinant human bone morphogenetic protein-2 (rhBMP-2) combined with monoolein or poloxamer gels, in critical bone defects of rats. Forty-five Wistar rats were divided into nine treatment groups with five animals each: I: application of 1 A mu g rhBMP-2 + monoolein; II: 3 A mu g rhBMP-2 + monoolein; III: 7 A mu g rhBMP-2 + monoolein; IV: 1 A mu g rhBMP-2 + poloxamer; V: 3 A mu g rhBMP-2 + poloxamer; VI: 7 A mu g rhBMP-2 + poloxamer; VII: monoolein only; VIII: poloxamer only; and IX: critical bone defect only. A critical-sized defect of 6 mm diameter was produced in the left parietal bone and it was filled with gels of the above mentioned treatments. After 2 weeks, the calvarial bones were removed for histological processing. Bone formation in the groups that received poloxamer gel and rhBMP-2 was not significantly different from the control group (IX). Groups receiving monoolein and rhBMP-2 (1 and 3 A mu g) and those that received only the carriers (VII and VIII) had less bone formation in relation to the control. The association of rhBMP-2 to both poloxamer and monoolein did not exhibit any significant differentiation in bone formation in comparison with the control group.

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Purpose: To assess, by a crossover 2 x 2 in situ study, the speculated protective role of a sodium bicarbonate-containing toothpaste in controlling erosive lesions. Methods: Bovine enamel slabs were sterilized, and submitted to baseline Knoop microhardness measurements. After a 3-day lead-in period, 14 volunteers wore palatal acrylic appliances containing six enamel slabs (three on each side), for 4 consecutive days. On the first day, appliances with contained specimens were placed in the oral cavity to allow salivary pellicle formation. On the subsequent days, half of the enamel slabs were immersed extraorally in a lemonade-like soft drink for 90 seconds, twice daily. On both of these occasions, the appliance was dipped in toothpaste slurry of either a sodium bicarbonate-containing toothpaste or a regular counterpart for 60 seconds. Following a 3-day washout period, a new set of enamel slabs were mounted and the volunteers started the second period using the alternate dentifrice. Results: ANOVA (alpha = 0.05) showed no statistically significant difference between enamel treated with regular and sodium bicarbonate-based dentifrices, regardless of whether specimens were eroded or not (P=0.8430). Acid-challenged specimens revealed lower microhardness values than uneroded samples. (Am J Dent 2008;21:300-302).

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The purpose of this in vitro study was to determine whether the vicinity of root dentine that had been restored with fluoride-releasing materials was at reduced risk for erosive/abrasive wear compared to root dentine restored with a non-fluoride-containing material. According to a randomized complete block design, standardized cavities prepared on the surface of 150 bovine root dentine slabs were restored with glass-ionomer cement, resin-modified glass ionomer, polyacid-modified resin composite, fluoride-containing or conventional composite. Specimens were coated with two layers of an acid-resistant nail varnish exposing half of the dentine surface and half of the restoration. Subsequently, specimens were either eroded in an acidic drink or left uneroded, then exposed to artificial saliva and abraded in a toothbrushing machine. Wear depth in the vicinity of restorations was quantified by a stylus profilometer, based on the nonabraded areas surrounding the erosion/abrasion region. Two-way ANOVA did not demonstrate significant interaction between restoratives and eroded-uneroded dentine (p = 0.5549) nor significant difference among restorative materials (p = 0.8639). Tukey`s test ascertained that the wear depth was higher for eroded than for uneroded groups. Fluoride-releasing materials seemed to negligibly inhibit wear in the vicinity of restored root dentine subjected to erosive/abrasive challenges.

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Leaf water potential (psi (l)) represents a good indicator of the water status of plants, and continuous monitoring of it can be useful in research and field applications such as scheduling irrigation. Changes in stem diameter (Sd) were used for monitoring psi (l) of pot-grown sorghum [Sorghum bicolor (L.) Moench] plants in a glasshouse. This method requires occasional calibration of S-d values against psi (l). Predicted values of psi (l), based on a single calibration show a good correlation with measured psi (l), values over a period of 13 d before and after the calibration. The correlation can further be improved with shorter time intervals.

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A range of topical products are used in veterinary medicine. The efficacy of many of these products has been enhanced by the addition of penetration enhancers. Evolution has led to not only a highly specialized skin in animals and humans, but also one whose anatomical structure and skin permeability differ between the various species. The skin provides an excellent barrier against the ingress of environmental contaminants, toxins, and microorganisms while performing a homeostatic role to permit terrestrial life. Over the past few years, major advances have been made in the field of transdermal drug delivery. An increasing number of drugs are being added to the list of therapeutic agents that can be delivered via the skin to the systemic circulation where clinically effective concentrations are reached. The therapeutic benefits of topically applied veterinary products is achieved in spite of the inherent protective functions of the stratum corneum (SQ, one of which is to exclude foreign substances from entering the body. Much of the recent success in this field is attributable to the rapidly expanding knowledge of the SC barrier structure and function. The bilayer domains of the intercellular lipid matrices within the SC form an excellent penetration barrier, which must be breached if poorly penetrating drugs are to be administered at an appropriate rate. One generalized approach to overcoming the barrier properties of the skin for drugs and biomolecules is the incorporation of suitable vehicles or other chemical compounds into a transdermal delivery system. Indeed, the incorporation of such compounds has become more prevalent and is a growing trend in transdermal drug delivery. Substances that help promote drug diffusion through the SC and epidermis are referred to as penetration enhancers, accelerants, adjuvants, or sorption promoters. It is interesting to note that many pour-on and spot-on formulations used in veterinary medicine contain inert ingredients (e.g., alcohols, amides, ethers, glycols, and hydrocarbon oils) that will act as penetration enhancers. These substances have the potential to reduce the capacity for drug binding and interact with some components of the skin, thereby improving drug transport. However, their inclusion in veterinary products with a high-absorbed dose may result in adverse dermatological reactions (e.g., toxicological irritations) and concerns about tissue residues. These a-re important considerations when formulating a veterinary transdermal product when such compounds ate added, either intentionally or otherwise, for their penetration enhancement ability. (C) 2001 Elsevier Science B.V. All rights reserved.

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Documentation of burn sequelae can be a difficult and time-consuming task. To date a reliable and systematic format for recording postburn trauma is lacking. The purpose of this research was two-fold: first, to develop a Modified Inventory of Potential Reconstructive Needs from the original Inventory of Potential Reconstructive Needs to allow methodical documentation of functional and cosmetic burn sequelae in all body surface areas of children with burns and, second, to establish interrater reliability and concurrent validity of the instrument, thus allowing its clinical application. Two raters scored the Modified Inventory of Potential Reconstructive Needs on 41 children with a range of burns types and severity. Excellent interrater reliability was demonstrated for both total (intraclass correlation coefficient = 0.996) and subsection inventory scores. Concurrent validity was also established with total scores showing strong positive correlations (0.73-0.76) with three indicators of burn severity. These findings provide initial support for the tool's clinical applicability, particularly in relation to rehabilitative planning and documentation.

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A method is described whereby sedimentation velocity is combined with equilibrium dialysis to determine the net charge (valence) of a protein by using chromate as an indicator ion for assessing the extent of the Donnan redistribution of small ions. The procedure has been used in experiments on bovine serum albumin under slightly alkaline conditions (pH 8.0, I 0.05) to illustrate its application to a system in which the indicator ion and protein both bear net negative charge and on lysozyme under slightly acidic conditions (pH 5.0, I 0.10) to illustrate the situation where chromate is a counterion. (C) 2001 Elsevier Science.

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This paper compares two hypothetical and identical vehicle deceleration profiles mirrored in time, one linearly descending with time and the other linearly ascending with time. The differences of such profiles on occupant velocity differential and by implication, injury levels at the point of occupant impact are presented. An indifference point is established to assist in comparing which occupant body part will benefit from the altered crash pulse. It is shown that for occupant proximity distances below the indifference point, an ascending profile results in lower injury risk. Above the indifference point, the result is reversed.

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Cape Roberts Project drill core 3 (CRP-3) was obtained from Roberts ridge, a sea-floor high located at 77°S, 12 km offshore from Cape Roberts in western McMurdo Sound, Antarctica. The recovered core is about 939 m long and comprises strata dated as being early Oligocene (possibly latest Eocene) in age, resting unconformably on ∼ 116 m of basement rocks consisting of Palaeozoic Beacon Supergroup sediments. The core includes ten facies commonly occuring in five major associations that are repeated in particular sequences throughout the core and which are interpreted as representing different depositional environments through time. Depositional systems inferred to be represented in the succession include: outer shelf, inner shelf, nearshore to shoreface each under iceberg influence, deltaic and/or grounding-line fan, and ice proximal-ice marginal-subglacial (mass flow/rainout diamictite/subglacial till) singly or in combination. The record is taken to represent the initial talus/alluvial fan setting of a glaciated rift margin adjacent to the block-uplifted Transantarctic Mountains. Development of a deltaic succession upcore was probably associated with the formation of palaeo-Mackay valley with temperate glaciers in its headwaters. At that stage glaciation was intense enough to support glaciers ending in the sea elsewhere along the coast, but a local glacier was fluctuating down to the sea by the time the youngest part of CRP-3 was being deposited. Changes in palaeoenvironmental interpretations in this youngest part of the core are used to estimate relative glacial proximity to the drillsite through time. These inferred glacial fluctuations are compared with the global δ18O and Mg/Ca curves to evaluate the potential of glacial fluctuations on Antarctica for influencing these records of global change. Although the comparisons are tentative at present, the records do have similarities, but there are also some differences that require further evaluation.

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We have utilised the combination of sensitivity and specificity afforded by coupling high-performance liquid chromatography (HPLC) to a tandem mass spectrometer (MS-MS) to produce an assay which is suitable for assaying glutathione (GSH) concentrations in liver tissue. The sensitivity suggests it may also be suitable for extrahepatic tissues, The method has been validated for GSH using mouse liver samples and also allows the assay of GSSG. The stability of GSH under conditions relevant to the assay has been determined. A 20-mul amount of a diluted methanol extract of tissue is injected with detection limits of 0.2 pmol for GSH and 2 pmol for GSSG. The HPLC uses an Altima C-18 (150X4.6 mm, 5 mum) column at 35 degreesC. Chromatography utilises a linear gradient from 0 to 10% methanol in 0.1% formic acid over 5 min, with a final isocratic stage holding at 10% methanol for 5 min. Total flow rate is 0.8 ml/min. The transition from the M+H ion (308.1 m/z for GSH, and 613.3 m/z for GSSG) to the 162.0 m/z (GSH) and 355.3 m/z (GSSG) fragments are monitored. (C) 2001 Elsevier Science B.V. All rights reserved.

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Alpha-Conotoxins are small disulfide rich peptides from the venoms of marine cone snails. They target specific nicotinic acetylcholine receptor (nAChR) subtypes with high affinity and potency and are therefore valuable as neurophamacological probes and potential drug leads. This article gives a general overview of the chemical and biological features of alpha -conotoxins, including their pharmacology, binding interactions and structure. A detailed analysis of recently reported three-dimensional structures from members of different subfamilies of the alpha -conotoxins, including those with 3/5, 4/3, 4/6 and 4.7 spacings of their two intracysteine loops is given. The structures are generally well defined and represent useful frameworks for the display of amino acid residues to target molecules.

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The potential for telemedicine in home nursing was examined by retrospectively reviewing the case-notes relating to home visits made by nurses in Queensland. The case-notes of 166 clients were randomly selected from 10 domiciliary nursing centres run by the Blue Care nursing organization in south-east Queensland. Two experienced community registered nurses independently undertook a retrospective review of the case-notes. Each reviewer made an independent judgement as to whether any of the home nursing visits in the episode of care could have been conducted by telemedicine. Visits requiring hands-on care were deemed to be unsuitable for telemedicine. A total of 12,630 home visits were reviewed. The median number of visits per client was 27 (range 1-722). The mean age of the clients was 72 years (range 2-93 years). A total of 1521 home visits (12%) were judged suitable for telemedicine. There was no significant difference in suitability between males (13%) and females (12%). Care interventions suitable for telemedicine were more likely to be those of a supportive, educational or review nature. Forty per cent of clients lived up to 5 km from the home nursing centre, 33% lived 5-10 km from the centre and 27% lived over 10 km from the centre. The results of the present study confirm the potential for telemedicine in home nursing in Australia.

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Saprophytic bacteria, yeasts and filamentous fungi were isolated from Geraldton waxflower flowers and screened to identify potential antagonism towards Botrytis cinerea. Isolates from other sources (e.g. avocado) were also tested. Isolates were initially screened in vitro for inhibition of B. cinerea conidial germination, germ tube elongation and mycelial growth. The most antagonistic bacteria, yeasts and fungi were selected for further testing on detached waxflower flowers. Conidia of the pathogen were mixed with conidia or cells of the selected antagonists, co-inoculated onto waxflower flowers, and the flowers were sealed in glass jars and incubated at 20 degreesC. The number of days required for the pathogen to cause flower abscission was determined. The most antagonistic bacterial isolate, Pseudomonas sp. 677, significantly reduced conidial germination and retarded germ tube elongation of B. cinerea. None of the yeast or fungal isolates tested was found to significantly reduce conidial germination or retard germ tube elongation, but several significantly inhibited growth of B. cinerea. Fusarium sp., Epicoccum sp. and Trichoderma spp. were the most antagonistic of these isolates. Of the isolates tested on waxflower, Pseudomonas sp. 677 was highly antagonistic towards B. cinerea and delayed waxflower abscission by about 3 days. Trichoderma harzianum also significantly delayed flower abscission. However, as with most of the fungal antagonists used, inoculation of waxflower flowers with this isolate resulted in unsightly mycelial growth.