Section thickness, macrohardness and yield strength in high-pressure diecast magnesium alloy AZ91

The yield strength of high-pressure diecast (hpdc) test bars of alloy AZ91 increases with decreasing section thickness while its hardness remains approximately constant. This behaviour is in contrast with that of the gravity cast alloy, whose hardness scales with the yield strength. Vickers hardness measured on the surface of hpdc test bars using increasing loads shows that the subsurface porosity layer usually found in hpdc material may gradually collapse under the indent, lowering the hardness. However, this is insufficient to explain the lack of correlation between hardness and yield strength. It is argued that the low strain-hardening rate of high-pressure diecast material leads to lower than expected hardness values. In addition, it is shown that the plastic zone under a macro indentation is largely contained by the softer core of the castings, rendering hardness insensitive to the casting thickness. It is concluded that macrohardness is too coarse a tool for a meaningful determination of the strength of hpdc material. (c) 2005 Elsevier B.V. All rights reserved.

Strength and attrition resistance of agglomerates and particulate coatings

The mechanical properties of a range of agglomerates and particulate coatings have been measured using a nanoindenter. The effect of formulation properties such as powder and binder properties on coating hardness is described. An attempt is also made to measure the fracture hardness with the nanoindenter. The use of indentation technology to measure fundamental agglomerate properties is critically analysed. Based on the indentation measurements and standard attrition test results, the coating hardness is found closely related to the attrition rate under standard conditions and can be used to screen different powder/binder formulations. (C) 2002 Elsevier Science B.V All rights reserved.

Valerian does not appear to reduce symptoms for patients with chronic insomnia in general practice using a series of randomised n-of-I trials

Objectives: To investigate the effectiveness of valerian for the management of chronic insomnia in general practice. Design: Valerian versus placebo in a series of n-of-1 trials, in Queensland, Australia. Results: Of 42 enrolled patients, 24 (57%) had sufficient data for inclusion into the n-of-1 analysis. Response to valerian was fair for 23 (96%) participants evaluating their 'energy level in the previous day' but poor or modest for all 24 (100%) participants' response to 'total sleep time' and for 23 (96%) participants' response to 'number of night awakenings' and 'morning refreshment'. As a group, the proportion of treatment successes ranged from 0.35 (95% CI 0.23, 0.47) to 0.55 (95% CI 0.43, 0.67) for the six elicited outcome sleep variables. There was no significant difference in the number (P = 0.06), distribution (P = 1.00) or severity (P = 0.46) of side effects between valerian and placebo treatments. Conclusions: Valerian was not shown to be appreciably better than placebo in promoting sleep or sleep-related factors for any individual patient or for all patients as a group. (C) 2003 Elsevier Ltd. All rights reserved.

Depth of cure and surface microhardness of composite resin cured with blue LED curing lights

Objectives. This study examined the depth of cure and surface microhardness of Filtek Z250 composite resin (3M-Espe) (shades B1, A3, and C4) when cured with three commercially available tight emitting diode (LED) curing lights [E-light (GC), Elipar Freelight (3M-ESPE), 475H (RF Lab Systems)], compared with a high intensity quartz tungsten halogen (HQTH) light (Kerr Demetron Optilux 501) and a conventional quartz tungsten halogen (QTH) lamp (Sirona S1 dental unit). Methods. The effects of light source and resin shade were evaluated as independent variables. Depth of cure after 40 s of exposure was determined using the ISO 4049:2000 method, and Vickers hardness determined at 1.0 mm intervals. Results. HQTH and QTH lamps gave the greatest depth of cure. The three LED lights showed similar performances across all parameters, and each unit exceeded the ISO standard for depth of cure except GC ELight for shade B1. In terms of shade, LED lights gave greater curing depths with A3 shade, while QTH and HQTH tights gave greater curing depths with C4 shade. Hardness at the resin surface was not significantly different between LED and conventional curing lights, however, below the surface, hardness reduced more rapidly for the LED lights, especially at depths beyond 3 mm. Significance. Since the performance of the three LED lights meets the ISO standard for depth of cure, these systems appear suitable for routine clinical application for resin curing. (C) 2003 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Amorphous structures induced in monocrystalline silicon by mechanical loading

Different amorphous structures have been induced in monocrystalline silicon by high pressure in indentation and polishing. Through the use of high-resolution transmission electron microscopy and nanodiffraction, it was found that the structures of amorphous silicon formed at slow and fast loading/unloading rates are dissimilar and inherit the nearest-neighbor distance of the crystal in which they are formed. The results are in good agreement with recent theoretical predictions. (C) 2004 American Institute of Physics.

The R8-BC8 phases and crystal growth in monocrystalline silicon under microindentation with a spherical indenter

The morphology and distribution of high-pressure metastable phases BC8 and R8, formed in monocrystalline silicon under microindentation, were identified and assessed using transmission electron microscopy nanodiffraction analysis. It was discovered that the crystal growth inside the transformation zone was stress-dependent with large crystals in its central region. The crystal size could also be increased using higher maximum indentation loads. The BC8 and R8 phases distributed unevenly across the transformation zone, with BC8 crystals mainly in the center of the zone and smaller R8 fragments in the peripheral regions. Such phase distribution was in agreement with the theoretical residual stress analysis.

Initiation of fungal epizootics in diamondback moth populations within a large field cage: proof of concept for auto-dissemination

Adult diamondback moths (DBM), Plutella xylostella L. (Lepidoptera: Plutellidae), inoculated with the fungus Zoophthora radicans, were released within a large field cage containing DBM-infested potted broccoli plants. Larvae and pupae on exposed and caged control plants were examined on five occasions over the next 48 days for evidence of Z. radicans infection. Infected larvae were first detected on exposed plants 4 days after the initial release of adults, and after 48 days the infection level reached 79%. Aerially borne conidia were a factor in transmission of the fungus. Infection had no effect on possible losses of larval and adult cadavers due to scavengers in field crops. In a trial to measure the influence of infection on dispersal, twice as many non-infected as infected males were recaptured in pheromone traps, although the difference in cumulative catch only became significant 3 days after release of the males. In a separate experiment, when adult moths were inoculated with Beauveria bassiana conidia and released into the field cage, DBM larvae collected from 37 of 96 plants sampled 4 days later subsequently died from B. bassiana infection. The distribution of plants from which the infected larvae were collected was random, but the distribution of infected larvae was clustered within the cage. These findings suggest that the auto-dissemination of fungal pathogens may be a feasible strategy for DBM control, provided that epizootics can be established and maintained when DBM population densities are low.

Dietary carbohydrate source affects glucose concentrations, insulin secretion, and food intake in overweight cats

This study was undertaken to assess the impact of dietary carbohydrate source on food intake, body composition, glucose tolerance, insulin sensitivity, and glucose and insulin concentrations in overweight and obese cats with reduced insulin sensitivity. Sixteen overweight and obese cats were divided into two groups and randomly allocated one of two extruded diets formulated to contain similar starch content (33%) from different cereal sources (sorghum and corn versus rice). Meal response, glucose tolerance and insulin sensitivity tests were performed before and after a 6-week weight-maintenance phase and after an additional 8-week free-access feeding phase. Dual energy x-ray absorptiometry (DEXA)-derived body composition was determined in each cat before the study and after each test phase. Food intake was measured daily and body weight measured twice weekly for the duration of the study. When compared with the sorghum/corn-based diet, cats fed the rice-based diet consumed more energy and gained more weight in response to free-access feeding. Cats fed the rice-based diet also tended to have higher glucose concentrations and insulin secretion in response to a glucose load or a test meal. We conclude that a sorghum and corn blend is a superior carbohydrate source than rice for overweight cats with glucose intolerance and reduced insulin sensitivity. Such a diet may help to minimize overeating and additional weight gain, and may also reduce the risk of developing type 2 diabetes mellitus. (C) 2004 Elsevier Inc. All rights reserved.

Naturopathic and Western herbal medicine practice in Australia - a workforce survey

Background: Despite substantial growth in the use of complementary medicine, no comprehensive national study has been undertaken of the naturopathic and Western herbal medicine component of the healthcare workforce in Australia. This study aimed to examine the nature of these practices and this currently unregulated workforce in Australia. Methods: A comprehensive survey questionnaire was developed in consultation with the profession and distributed nationally to all members of the naturopathic and Western herbal medicine workforce. Results: The practices of herbal medicine and naturopathy make up a sizeable component of the Australian healthcare sector, with approximately 1.9 million consultations annually and an estimated turnover of $AUD 85 million in consultations (excluding the cost of medicines). A large proportion of patients are referred to practitioners by word of mouth. Up to one third of practitioners work in multidisciplinary clinics with other registered sectors of the healthcare community. The number of adverse events associated with herbal medicines, nutritional substances and homoeopathic medicines recorded in Australia is substantial and the types of events reported are not trivial. Data suggest that practitioners will experience one adverse event every 11 months of full-time practice, with 2.3 adverse events for every 1000 consultations (excluding mild gastrointestinal effects). Conclusion: These data confirm the considerable degree of utilisation of naturopathic and Western herbal medicine practitioners by the Australian public. However, there is a need to examine whether statutory regulation of practitioners of naturopathy and Western herbal medicine is required to better protect the public. (C) 2004 Elsevier Ltd. All rights reserved.

Erosive effects of common beverages on extracted premolar teeth

Background: Dental erosion is highly prevalent today, and acidic drinks are thought to be an important cause. The aim of the present investigation was to determine the erosive potential of a range of common beverages on extracted human teeth. Methods: The beverages were tested for their individual pHs using a pH meter. The clinical effects of the most erosive beverages were determined by the degree of etching and Vickers microhardness of enamel. Results: The results showed that many common beverages have pHs sufficiently low to cause enamel erosion. Lime juice concentrate (pH 2.1) had the lowest pH, followed by Coca-cola and Pepsi (both with pH 2.3) and Lucozade (pH 2.5). The erosive potential of these beverages was demonstrated by the deep etching of the enamel after five minutes. The Vickers Hardness of enamel was reduced by about 50 per cent is the case of lime juice (p < 0.001) and 24 per cent in the case of Coca-cola (p < 0.004). Addition of saliva to 50 per cent (v/v) of Coca-cola completely reversed the erosive effects on the enamel. Conclusion: Although only a few of the beverages with the lowest pHs were tested, the present study showed that the most acidic drinks had the greatest erosive effects on enamel. While saliva was protective against erosion, relatively large volumes were required to neutralize the acidity.

Analysis of the acute postoperative pain experience following oral surgery: identification of 'unaffected', 'disabled' and 'depressed, anxious and disabled' patient clusters

Background: Pain is defined as both a sensory and an emotional experience. Acute postoperative tooth extraction pain is assessed and treated as a physiological (sensory) pain while chronic pain is a biopsychosocial problem. The purpose of this study was to assess whether psychological and social changes Occur in the acute pain state. Methods: A biopsychosocial pain questionnaire was completed by 438 subjects (165 males, 273 females) with acute postoperative pain at 24 hours following the surgical extraction of teeth and compared with 273 subjects (78 males, 195 females) with chronic orofacial pain. Statistical methods used a k-means cluster analysis. Results: Three clusters were identified in the acute pain group: 'unaffected', 'disabled' and 'depressed, anxious and disabled'. Psychosocial effects showed 24.8 per cent feeling 'distress/suffering' and 15.1 per cent 'sad and depressed'. Females reported higher pain intensity and more distress, depression and inadequate medication for pain relief (p

A novel cis-acting element, ESP, contributes to high-level endosperm-specific expression in an oat globulin promoter

To examine the genetic controls of endosperm (ES) specificity, several cereal seed storage protein (SSP) promoters were isolated and studied using a transient expression analysis system. An oat globulin promoter (AsGlo1) capable of driving strong ES-specific expression in barley and wheat was identified. Progressive 5' deletions and cis element mutations demonstrated that the mechanism of specificity in the AsGlo1 promoter was distinct from that observed in glutelin and prolamin promoters. A novel interrupted palindromic sequence, ACATGTCAT-CATGT, was required for ES specificity and substantially contributed to expression strength of the AsGlo1 promoter. This sequence was termed the endosperm specificity palindrome (ESP) element. The GCN4 element, which has previously been shown to be required for ES specificity in cereal SSP promoters, had a quantitative role but was not required for tissue specificity. The 960-bp AsGlo1 promoter and a 251-bp deletion containing the ESP element also drove ES-specific expression in stably transformed barley. Reporter gene protein accumulated at very high levels (10% of total soluble protein) in ES tissues of plants transformed with an AsGlo1:GFP construct. Expression strength and tissue specificity were maintained over five transgenic generations. These attributes make the AsGlo1 promoter an ideal promoter for biotechnology applications. In conjunction with previous findings, our data demonstrate that there is more than one genetically distinct mechanism by which ES specificity can be achieved in cereal SSP promoters, and also suggest that there is redundancy between transcriptional and post-transcriptional tissue specificity mechanisms in cereal globulin genes.

Dinosaur sanctuary on the Chatham Islands, Southwest Pacific: First record of theropods from the K-T boundary Takatika Grit

Cretaceous-Tertiaty (K-T) boundary (ca. 65 Ma) sections on a Southwest Pacific island containing dinosaurs were unknown until March 2003 when theropod bones were recovered from the Takatika Grit on the remote Chatham Islands (latitude 44 degrees S, longitude 176 degrees W), along the Chatham Rise. Tectonic and palaeontologic evidence support the eastward extension of a ca. 900 km land bridge that connected the islands to what is now New Zealand prior to the K-T boundary. The Chathams terrestrial fauna inhabited coastal, temperate environments along a low-lying, narrow, crustal extension of the New Zealand subcontinent, characterised by a tectonically dynamic, volcanic landscape with eroding hills (horsts) adjacent to flood plains and deltas, all sediments accumulating in grabens. This finger-like tract was blanketed with a conifer and clubmoss (Lycopodiopsida) dominated forest. The Chatham Islands region would have, along with New Zealand, provided a dinosaur island sanctuary after separating from the Gondwana margin ca. 80 Ma. (c) 2005 Elsevier B.V. All rights reserved.

Age determination in individual wild-caught Drosophila serrata using pteridine concentration

Fluorescence spectrophotometry can reliably detect levels of the pteridine 6-biopterin in the heads of individual Drosophila serrata Malloch 1927. Pteridine content in both laboratory and field captured flies is typically a level of magnitude higher than the minimally detectable level (mean(lab)=0.54 units, mean(field)=0.44 units, minimum detectable level=0.01 units) and can be used to predict individual age in laboratory populations with high certainty (r(2)=57%). Laboratory studies of individuals of known age ( from 1 to 48 days old) indicate that while pteridine level increases linearly with age, they also increase in a linear manner with rearing temperature and ambient light levels, but are independent of sex. As expected, the longevity of laboratory-reared males ( at least 48 days) is higher than the range of predicted ages of wild-caught males based on individual pteridine levels (40 days). However, the predictive equation based on pteridine level alone suggested that a number of wild-caught males were less than 0 days old, and the 95% confidence for these predictions based on the inverse regression broad. The age of the oldest wild-caught male is to fall within the range of 2 to 50 days. The effects of temperature and light intensity determined in laboratory study (effect sizes omega(2)=14.3 and respectively) suggests that the calibration of the prediction equation for field populations would significantly improved when combined with fine scaled studies of habitat temperature and light conditions. ability to determine relative age in individual wild-caught D. serrata presents great opportunities for a variety evolutionary studies on the dynamics of populations.