Search

Decadal limestone erosion rates from a 30-year study of St Pauls Cathedral, London are compared with recession rates derived from applying Lipfert’s and Tidblad’s dose-response functions to the available rainfall and sulphur dioxide data from central London. Comparison of the measured erosion rates and the dose-response function derived recession rates shows consistently higher loss for the measured erosion rates, between 49 and 35 microns per year for measured rates as opposed to 15e12 microns per year for derived rates. Measured erosion rates were 3.33 times as high as derived recession rates towards the start of the 30 year measurement period, falling to almost 2.75 times by the 2000s. Analysis of the disparity suggests that, despite the magnitude of the differences between the two methods, they both record the same patterns of decline in erosion rates as sulphur dioxide levels decline. The disparity may result from using a common index of erosion, loss of height, to express the outcomes of two different measurement systems quantifying surface loss in different ways.

Background: Dental erosion is an increasingly prevalent problem in Australia, with the consumption of sports beverages suggested as a risk factor. The aim of this study was to compare the erosive potential of Australian sports beverages. Methods: Ten beverages were selected and analysed to determine their pH, titratable acidity and apparent degree of saturation with respect to apatite. The erosive potential of the beverages was measured by human enamel surface loss and surface softening following a 30-minute exposure. A taste testing panel was established to determine the palatability of the sports beverages. Results: All sports beverages except Sukkie and Endura produced substantial surface loss and surface softening. Compared with the other sports beverages, Sukkie and Endura had a higher pH, lower titratable acidity and higher calcium content. However, Sukkie and Endura were deemed to be less palatable than the other more acidic sports beverages. Conclusions: The majority of the sports beverages tested produced dental erosion in this in vitro model. However, two new products Sukkie and Endura have lower erosive potential but also lower palatability.

Thin layer activation (TLA) technique is a powerful nuclear technique based on the production of a radioisotope in the surface of a material by a charged particle induced nuclear reaction, followed by an estimation of the loss of the activity which is a measure of the surface loss of materials in the range of nanometer to hundreds of micrometer in the fields of wear, corrosion or erosion. The technique has been found to be a very useful tool in the basic scientific research and industrial applications. The present review describes the basic principle of TLA technique, its characteristic features, methodology, scope, applications and various recent developments regarding its growing use. Some of our earlier TLA work carried out with α and heavy ion (16O) in various applied areas is also included here. Heavy ions were used because no other light ions (particularly protons) were available at our cyclotron.

Background: Matrix metalloproteinase (MMP) inhibitors reduce dentine erosion. This in vitro study evaluated the effect of the supplementation of soft drinks with green tea extract, a natural inhibitor of MMPs, on their erosive potential against dentine. Methods: For each drink tested (Coca-Cola™, Kuat™ guarana, Sprite™ and light Coca-Cola™), 40 dentine specimens were divided into two subgroups differing with respect to supplementation with green tea extract at 1.2% (OM24®, 100%Camellia sinensis leaf extract, containing 30 ± 3% of catechin; Omnimedica, Switzerland) or not (control). Specimens were subjected to four pH cycles, alternating de- and remineralization in one day. For each cycle, samples were immersed in pure or supplemented drink (10 minutes, 30 mL per block) and in artificial saliva (60 minutes, 30 mL per block) at 37 °C, under agitation. Dentine alterations were determined by profilometry (μm). Data were analysed by two-way ANOVA and Bonferroni’s test (p

The recombinative surface loss of O3 was investigated and its effects on the initial growth, film uniformity, and film conformality in atomic layer deposition (ALD) processes were illustrated. To determine O3 recombination probabilities over a wide range, a method was developed using high aspect ratio capillaries at the inlet to a mass spectrometer. Using this method, we measured O3 recombination probabilities ranging from 10-3 depending on the composition and temperature of the capillary surface. We utilized these measurements to understand dramatic variations in O3 loss observed during the initial growth of O3-based ALD Pt on Al2O3 and vice versa. Next, we studied the uniformity of O3-based ALD using ZnO ALD as a model system. Changes in the spatial uniformity of the ALD ZnO films and the O3 concentration in the reactor as a function of the O3 exposure were explained by a transition from reaction- to recombination-limited growth. This explanation was validated using a simple plug-flow model. Finally, we estimated the maximum aspect ratios that can be coated for a given O3 recombination probability in O3-based ALD processes using reasonable cycle times.

Summary Background Although dermatoglyphic structure has been mechanistically related to fingerprint formation, a separate mechanism for fingerprint maintenance must exist or prints would be lost by friction. Objectives To test this prediction and study its operation. Methods Palmar and plantar prints were studied visually and by silicone rubber impressions after surface removal by abrasives, scalpel and adhesive stripping, using surface staining to stage surface loss. Results All depths and methods of surface removal left the print ridges intact visually and in silicone rubber impressions. When abrasion was applied only to ridge surfaces, keratinocytes were lost concomitantly in the troughs between them, leaving ridge structure intact. When palmar or plantar stratum corneum was cleaved or peeled apart, the separated layer followed the undulating ridges and troughs, thus maintaining the normal print pattern. Conclusions A new mechanism of fingerprint maintenance was predicted theoretically and confirmed experimentally. It is achieved by an organization of the print corneum which ensures its continuous separation over the whole of the undulating print surface, even when friction is applied only to the tips of the ridges; the preferred route of separation of print keratinocytes runs up and down the print ridges and troughs and thereby maintains them, and is presumably ordered by predominantly horizontal intercellular attachments between print keratinocytes. The reason print maintenance has been missed until now may be that dermatoglyphic researchers have little interest in fingerprint disguise, while those who are interested in disguise have little interest in research.

The article discusses the results of thermal imaging monitoring of building structures with and without insulation. Research and thermal and physical calculations showed that heat loss from the premises is determined by two groups of factors: surface loss depending on thermal conductivity, as well as vapor and air permeability of enclosing elements and heat loss at all types of joints, fasteners, etc. Thermal insulation with plate materials significantly reduces heat losses, but at the same time, heat flows through the joints between the heat-insulating plates and in the areas of their contact with other structures, necessitating the use of steam and waterproof windproof roll materials. The usage of elastic and thermoplastic materials in the insulation circuit allows minimizing heat loss at the joints between the heat-insulating elements and along the smooth surface of the wall due to the low air and vapor permeability of the material. In the systems of frame cottages, when used as a thermal insulation of rolled foam-polyethylene, it becomes possible to form a seamless insulating shell of a building. This is made possible by connecting individual sheets of polyethylene foam into a lock, followed by hot air welding. Seamless insulation systems are used both in the construction of cottages and in the construction of frame and frameless logistic facilities and housing and communal services.

Stratum corneum (SC) readily dislodgeable exfoliation could affect percutaneous absorption and thus influence treatment and toxicological effects. Urea, a classical enhancer, is absorbed less than 1% in vivo in man and might be a useful marker to quantify chemical-drug exfoliation. This study develops a simple model utilizing washing and tape-stripping to quantify surface loss of chemicals topically applied on human skin and estimate the extent of chemical-drug SC exfoliation.Urea, 10% as a model hydrophilic chemical marker, was applied to human skin on identical sites (5 cm(2)/area with 1.8 mg/cm(2) urea) in vitro and in vivo. At time points 0, 4, and 6 h, the area was washed, rubbed, and stripped five times with cellophane tape. Quantitative urea was performed by colorimetric assay.The data of the in vitro protected non-exfoliating model, as the control, showed no statistical difference between 0-, 4-, and 6-h recovery (P 0.05). In the air-exposed model in vivo exfoliation in man, the recovery decreased from 98.8 ± 3.7% to 93.9 ± 6.8% in 4 h and 86.4 ± 3.0% in 6 h (P = 0.02). In the cloth-covered model in vivo, the recovery decreased from 99.4 ± 5.8% to 84.9 ± 5.3% in 4 h (P = 0.04), which reached 73 ± 2.8% within 6 h (P = 0.007).This study suggests that urea, measured with washing, rubbing, and tape-stripping, can be used as a possible chemical-drug SC readily dislodgeable exfoliation and friction rubbing metric. In addition, this might help to determine the rule of skin exfoliation in dermatopharmacologic and dermatoxicologic assessment.

The aims of this study were to compare daily versus single applications of low-concentration TiF4 solutions for reduction of enamel erosion and to evaluate the enamel surface loss due to application of these solutions. Sixty bovine enamel samples were randomly divided into 2 groups: single versus daily treatment with TiF4 solution (ST vs. DT), which were subdivided into 5 subgroups (n = 6): 0% (control); 0.1, 0.5, 0.75 and 1% TiF4 concentration. Fluoride treatment was performed by immersing specimens in 10 ml of the TiF4 solutions for 5 min and rinsing them with tap water for 30 s. ST specimens were treated once only, DT specimens were treated before each erosion cycle. All specimens were subjected to 4 erosion cycles: 6 immersions of 2 min in Sprite, tap water rinse for 1 min and storage in artificial saliva for 1.5 h. Erosive enamel loss was measured using light profilometry, after each fluoride treatment and each erosive cycle. The values of surface loss/gain at application of the TiF4 solutions did not significantly differ from zero. At the end of the 4 erosion cycles, 0.5% showed the least (ST: 3.45 ± 0.27 µm, DT: 1.08 ± 1.69 µm) and 1% showed the most surface loss (ST: 4.87 ± 1.13 µm, DT: 6.56 ± 1.49 µm). A significant reduction of surface loss was found only for 0.5% DT (p = 0.009). Within the limitations of an in vitro study, it was concluded that multiple applications of a 0.5% TiF4 solution significantly reduced enamel erosion in vitro and caused no enamel loss at application.

Background: Dental erosion is an increasingly prevalent problem in Australia. The aim of this study was to analyse the composition and erosive potential of beverages sold for consumption in Victorian schools. Methods: Fifteen drinks were selected and analysed to determine their pH, titratable acidity and ionic composition (calcium, fluoride and inorganic phosphate). The erosive potential of the beverages was measured by analysing weight loss, surface loss and the release of calcium ions from human enamel following a 30-minute or 24-hour exposure. The association of the chemical parameters with the measures of erosion was determined using Spearman’s rank correlation. Results: All beverages tested except the milks and the bottled water produced significant dental erosion in vitro. The only chemical parameter that correlated significantly with all measures of erosion was the initial pH of the beverage (p

This study aimed to analyse and compare the protective effect of buffered (pH 3.5) and native (pH 1.2) TiF4 in comparison with NaF solutions on enamel erosion. Bovine samples were pretreated with 1.50% TiF4 or 2.02% NaF (both 0.48 M F) solutions, each at a pH of 1.2 and 3.5. The control group received no fluoride pretreatment. Twenty samples per group were eroded with HCl (pH 2.6) for 10 × 60 s. Erosion was either investigated by profilometry (n = 10) or by determination of calcium release into the acid (n = 10). Additionally, the elemental surface composition was quantified by X-ray energy-dispersive spectroscopy in fluoridated but not eroded samples (6 samples per group). Scanning electron microscopy was performed prior and after erosion (2 samples per group). Cumulative enamel loss (μm) and calcium release (nmol/mm2) were analysed by repeated-measures ANOVA. The Ti and F surface composition was analysed by one-way ANOVA separately for each element. Only TiF4 at pH 1.2 reduced enamel surface loss significantly. Calcium release was significantly reduced by TiF4 and NaF at pH 1.2, but not by the solutions at pH 3.5. Samples pretreated with TiF4 at pH 1.2 showed a significant increase in Ti, while NaF increased F concentration significantly. Only TiF4 at pH 1.2 induced the formation of a glaze-like layer, which was still present after erosion. Enamel erosion can be significantly reduced by TiF4 at pH 1.2 but not at pH 3.5. TiF4 at pH 1.2 was more effective in protecting against enamel erosion than NaF.

This manuscript illustrates the management of a patient with anterior tooth surface loss. Specifically, the value of dentine-bonded crowns in the restorative management of the case is discussed as well as demonstrating the aesthetic result that can be achieved.Dentine-bonded crowns may be appropriate in treating a patient with advanced anterior tooth surface loss.

Supraglacial ponds on Tasman Glacier, New Zealand, initiated the development of the large Tasman Lake during the 1980s and still play an important role for ice loss and further terminus disintegration. Limnological and glaciological measurements between 2001 and 2003 reveal distinct differences between ponds. The hydraulic connection of a pond to the englacial water level exerts a key control on whether the pond contributes to longer-term terminus disintegration. In the earlier stages of pond development, ice loss occurs predominantly in the horizontal dimension by subaerial melt. Subaqueous calving at later stages plays a major role for ice loss. During the capture of a pond by the lake, substantial limnological changes lead to changes in relative significance and rates of ice loss processes, the most important being the change from melting to predominantly calving. As a result, ice loss accelerated from around 11 m a−1 of melt under partial debris cover to a retreat by calving and melting of 34 m a−1. Ice loss at the ponds accounted for only 10% of the surface loss in the lower terminus area, but is likely to increase in the future with enlargement and coalescence of ponds.

Superconducting qubits are sensitive to a variety of loss mechanisms including dielectric loss from interfaces. By changing the physical footprint of the qubit it is possible to modulate sensitivity to surface loss. Here we show a systematic study of planar superconducting transmons of differing physical footprints to optimize the qubit design for maximum coherence. We find that qubits with small footprints are limited by surface loss and that qubits with large footprints are limited by other loss mechanisms which are currently not understood., Comment: 5 pages

Investigations of viscoelastic composite materials and structural members carried out using the TDLTSDB and initial-imperfection method are reviewed. The investigations address the internal and surface loss of stability of layered and fibrous composites, the loss of stability of plates, and the delamination (buckling) of plates with cracks. Each of these problems is reviewed separately. New areas of further research are proposed. The review focuses on the investigations carried out by the author and his students

The species density distributions in a large post-discharge reactor placed downstream from a flowing microwave discharge in N2?O2 are calculated using a three-dimensional hydrodynamic model. The effects of surface losses of N(4S) and O(3P) atoms on the density distributions of different species in the reactor are investigated for three different wall materials: (i) Pyrex, (ii) aluminium and (iii) stainless steel. The effects produced by considering different surface loss probabilities corresponding to each one of these materials, as well as by assuming the production of NO from the wall, are evaluated and discussed. The simulation is conducted for the case of a 65 ? 25 ? 25?cm3 post-discharge reactor fed from a 2450?MHz discharge, at 2?Torr and 2 ? 103?sccm flow rate, in an N2?xO2 mixture composition, with x = 0.5?7%.

Objective Mouthrinsing with antacids, following erosive episodes, have been suggested as a preventative strategy to minimize tooth surface loss due to their neutralizing effect. The purpose of this in situ study was to evaluate the effect of an antacid suspension containing sodium alginate, sodium bicarbonate and calcium carbonate in controlling simulated erosion of enamel of intrinsic origin. Design The experimental units were 48 slabs (3 × 3 × 2 mm) of bovine enamel, randomly divided among 12 volunteers who wore palatal appliances with two enamel slabs. One of them was exposed extra-orally twice a day to 25 mL of a hydrochloric acid (HCl) solution (0.01 M, pH 2) for 2 min. There were two independent phases, lasting 5 days each. In the first phase, according to a random scheme, half of the participants rinsed with 10 mL of antacid suspension (Gaviscon®, Reckitt Benckiser Healthcare Ltd.), while the remainder was rinsed with deionized water, for 1 min. For the second phase, new slabs were inserted and participants switched to the treatment not received in the first stage. Therefore, the groups were as follows: (a) erosive challenge with HCl + antacid suspension; (b) erosive challenge with HCl + deionized water (DIW); (c) no erosive challenge + antacid suspension; (d) no erosive challenge + DIW. Specimens were assessed in terms of surface loss using optical profilometry and Knoop microhardness. The data were analyzed using repeated measures two-way analysis of variance and Tukey’s tests. Results Compared to DIW rinses, surface loss of enamel was significantly lower when using an antacid rinse following erosive challenges (p = 0.015). The Knoop microhardness of the enamel was significantly higher when the antacid rinse was used (p = 0.026). Conclusions The antacid suspension containing sodium alginate, sodium bicarbonate and calcium carbonate, rinsed after erosive challenges of intrinsic origin, reduced enamel surface loss.

Upon consecutive heat treatments at increasing temperatures, the microstructure of solution–sol–gel-derived stannic oxide (SnO2) xerogel evolves in three stages: (I) below 300°C, characterized by extensive dehydroxylation and gel shrinkage with little grain growth and surface loss; (II) between 300° and 500°C, by extensive crystallization, leading to dramatic surface loss (by 70%); and (III) above 500°C, by grain growth. Concurrently, the UV-absorption edge shows red shifts during stages I and II and blue shifts during stage III, resulting in distinct color variations. The edge displacement bears a close correlation with a Raman “defect band” at ∼305–328 cm−1.

A new construction scheme for a time-discrete version of the Stefan problem with Gibbs–Thomson law is introduced. Extending a scheme due to Luckhaus [11] our approach uses a local minimisation of certain penalised functionals instead of minimising these functionals globally. The main difference is that local minimisation allows for surface loss of approximate phase interfaces in the limit. The theory of varifolds is used to obtain the convergence of approximate Gibbs–Thomson equations. A particular situation exhibits that local minimisation provides more physically appealing solutions than those constructed by global minimisation.

Impedance transformation theory has been applied in order to describe a spherical Fabry-Perot resonator with monolithic dielectric samples at different positions along the resonator axis. The information due to different sample positioning in the resonator allows increasing accuracy in the evaluation of dielectric properties. Low loss materials like CVD-diamonds were taken as test specimens. The formalism can be extended to the case of sequences of dielectric layers. Experimental and modelling results are presented for two cases of sample geometry: resonant and anti-resonant. As an example the influence of additional surface loss on resonator parameters is quantified.

Decoherence of superconducting transmon qubits is purported to be consistent with surface loss from two-level systems on the substrate surface. Here, we present a study of surface loss in transmon devices, explicitly designed to have varying sensitivities to different surface loss contributors. Our experiments also encompass two particular different sapphire substrates, which reveal the onset of a yet unknown additional loss mechanism outside of surface loss for one of the substrates. Tests across different wafers and devices demonstrate substantial variation, and we emphasize the importance of testing large numbers of devices for disentangling different sources of decoherence., Comment: 4 pages, 3 figures

AIM: The aim of our pilot study was to determine the prevalence of dental erosion, the impact of beverages on the level of damage to the permanent teeth. MATERIAL AND METODS: For the purpose of the study we have included 105 respondents with positive indications of dental erosion aged 10 to 60 and < 60 years, and on specially prepared forms we have noted the extent of erosion and beverage consumption habits. RESULTS: The results of the level of erosion on the respondents’ first permanent incisors indicated that on age 10-29 they were with surface enamel loss, and with patient’s age the erosion was more present, where besides the loss of enamel there was presence of exposed dentin. Studies of the dental erosion on first permanent molars, related to the depth, depending on the age of respondents, indicated different clinical pictures. There was no respondent with enamel within normal limits. Surface loss was most present among respondents aged 10-29, loss of enamel with exposed dentin had the majority of respondents from the elderly group that also had respondents with attacked enamel and dentin but also an exposed pulp. The results show that most of the respondents consumed soft drinks 3-5 times a day, while most of them where male, and the consumption of fruit juices several times a day unfortunately was as present among male as among female respondents. There was positive correlation between the consumption of soft drinks and fruit juices in the total sample of respondents with dental erosion and all groups of respondents (р < 0.05), and between male and female respondents (р < 0.00). CONCLUSON: In conclusion, it is necessary to prepare a study by exploring the most influential etiological factors that would help in structuring preventive strategies.

In the course of testing and selecting the EPIC MOS CCDs for the XMM-Newton observatory, the authors developed a Monte-Carlo model of the CCD response. Among other things, this model was used to investigate surface loss effects evident at low energies. By fitting laboratory data, these losses were characterised as a simple function of X-ray interaction depth and this result enabled the spectral re-distribution itself to be modelled as a simple analytical function. Subsequently, this analytical function has been used to generate the response matrix for the EPIC MOS instruments and will now be employed to model the spectral re-distribution for the Swift XRT CCD.

OBJECTIVE: To evaluate a novel device for its efficacy in removing experimental biofilm from root surfaces and its potential for concomitantly removing/roughening the surface substance. METHODS AND MATERIALS: A novel acrylic rotary device (biofilm remover, BR) was tested in vitro in three experiments: surface loss, surface roughness [positive controls: Perioset (PS) and Proxoshape (PR)] and biofilm removal [positive controls: ultrasonic (US) and PS]. Surface loss/surface roughness was evaluated for dentin samples instrumented for three 20 s periods. The calcium removed during instrumentation was analysed after each interval and cumulatively, using atomic absorption spectrophotometry (AAS). Surface roughness was measured using profilometric analysis. Biofilm removal was evaluated on dentin specimens coated with a 64.5 h 6-species in vitro formed biofilm, after one 20 s treatment. Surface loss was analysed using anova with Scheffe post hoc test, and surface roughness/biofilm removal was analysed using Mann-Whitney test (all P ≤ 0.05). RESULTS: Significantly less substance loss [μg (±1 SD)] was observed with the novel device at all time points, both interval and cumulative (1.0 (±0.5) versus 9.3 (±3.2) PS and 9.9 (±1.9) PR at 60 s). Surface roughness [μm (95% CI)] was significantly lower for BR than for PS and PR [0.00 (-0.01, 0.08) 0.20 (0.16, 0.27) and 0.21 (0.19, 0.24) at 60 s]. Significantly less biofilm bacteria remained after treatment with both BR 4.5 (-0.1, 16.2) and US 1.9 (-0.2, 14.3), compared to PS 52 (27.9, 82.1). CONCLUSIONS: The novel biofilm remover was less damaging to dentin surfaces, while removing biofilm at least as effectively as devices used in this study.

This study aimed to compare the effect of two concentrations of triple antibiotic paste (TAP) with or without ethylenediaminetetraacetic acid (EDTA) on surface loss and surface roughness of radicular dentine. Human radicular dentine specimens were randomized into six experimental groups (n = 16 per group). The first and second groups were treated with 1,000 mg/mL or 1 mg/mL of TAP for 4 weeks. The third and fourth groups were treated with 1,000 mg/mL or 1 mg/mL of TAP for 4 weeks followed by 17 % EDTA for 5 min. The fifth group was treated with 17 % EDTA for 5 min and the sixth group received no treatment (control). Dentine surface loss and surface roughness were quantified after various treatments using optical and contact profilometry, respectively. One-way ANOVA followed by Fisher's protected least significant differences was used for statistical analyses. All treatment groups showed significantly higher surface loss compared to the untreated dentine. Dentine treated with 1,000 mg/mL had significant increase in surface loss and surface roughness compared to dentine treated with 1 mg/mL of TAP. The use of EDTA after both concentrations of TAP did not have significant additive effect on surface loss and surface roughness of dentine. The clinically used concentration of TAP (1,000 mg/mL) caused significantly higher surface loss and surface roughness of radicular dentine compared to the use of 1 mg/mL of TAP. Furthermore, the substantial amount of dentine surface loss and surface roughness detected in the current study may be attributed to TAP rather than EDTA.

Objective This study was performed to assess the risk of at-home and in-office bleaching procedures, and to recognise potential predictors for side effects. Design Multi-centre, questionnaire-based prospective study with follow-ups at around 14 days and around one year post-treatment. Setting General practices and university clinics during the years 2007-2009 in Scandinavia. Subjects Patients with tooth bleaching as part of the treatment plan. Results The prevalence of experienced tooth sensitivity at first follow-up was independent of bleaching procedure (at-home = 50.3% [n = 143]; in-office = 39.3% [n = 28]; p >0.05; 95% CI [OR]: 0.1981.102) whereas prevalence of gingival irritation was higher after in-office treatment (at-home = 14.0%; in-office = 35.7%; p

We measured the mechanical loss of crystalline anisotropic samples (silicon and sapphire) using a nodal support. The measured quality factor of the silicon sample reached 1.0×10 8 at room temperature. The sapphire sample showed lower quality factors, 6.4×10 7 at most, which were analytically confirmed to be dominated by surface loss.

We have analyzed decay kinetics of CF2 radicals in the afterglow of low-pressure, high-density C4F8 plasmas. The decay curve of CF2 density has been approximated by the combination of first- and second-order kinetics. The surface loss probability evaluated from the frequency of the first-order decay process has been on the order of 10−4. This small surface loss probability has enabled us to observe the second-order decay process. The mechanism of the second-order decay is self-association reaction between CF2 radicals (CF2+CF2→C2F4). The rate coefficient for this reaction has been evaluated as (2.6–5.3)×10−14 cm3/s under gas pressures of 2 to 100 mTorr. The rate coefficient was found to be almost independent of the gas pressure and has been in close agreement with known values, which are determined in high gas pressures above 1 Torr.

This note records the recent rapid retreat of the terminus of Glaciar San Quintin, which drains the western edge of the Hielo Patagonico Norte (HPN) in southern Chile. In 1993, the glacier terminus was advancing strongly into vegetated ground, while from 1996 to May 2000 the glacier underwent a transition between advance and retreat. A satellite image taken in 2000 showed that the ice front was undergoing substantial retreat and calving into proglacial lakes. Our research suggests that the glacier had lost an average of 1.89 km2 a−1 in ice surface between 1996 and 2000. The total surface loss is 7.55 km2, by far the largest retreat documented for the glaciers of the HPN since 1945.

Dental erosion is the loss of dental hard tissues caused by non-bacterial acids. Due to acid contact, the tooth surface becomes softened and more prone to abrasion from toothbrushing. Dentifrices containing different active agents may be helpful in allowing rehardening or in increasing surface resistance to further acidic or mechanical impacts. However, dentifrices are applied together with brushing and, depending on how and when toothbrushing is performed, as well as the type of dentifrice and toothbrush used, may increase wear. This review focuses on the potential harmful and helpful effects associated with the use of dentifrices with regard to erosive wear. While active ingredients like fluorides or agents with special anti-erosive properties were shown to offer some degree of protection against erosion and combined erosion/abrasion, the abrasive effects of dentifrices may increase the surface loss of eroded teeth. However, most evidence to date comes from in vitro and in situ studies, so clinical trials are necessary for a better understanding of the complex interaction of active ingredients and abrasives and their effects on erosive tooth wear. peerReviewed

Objective The study was performed to assess the risk of at-home and in-office bleaching procedures, and to recognise potential predictors for side effects. Design Multi-centre, questionnaire-based prospective study with follow-ups at around 14 days and around one year post-treatment. Setting General practices and university clinics during the years 2007-2009 in Scandinavia. Subjects Patients with tooth bleaching as part of the treatment plan. Results The prevalence of experienced tooth sensitivity at first follow-up was independent of bleaching procedure (at-home = 50.3% [n = 143]; in-office = 39.3% [n = 28]; p >0.05; 95% CI [OR]: 0.198-1.102) whereas prevalence of gingival irritation was higher after in-office treatment (at-home = 14.0%; in-office = 35.7%; p

Objectives This in situ trial study was designed to evaluate whether calcium (Ca) pre-rinse would increase the fluoride (F) rinse protection against enamel erosion. Methods Fifteen volunteers participated in this split-mouth, 3-phase, crossover design study wearing a palatal appliance containing four sterilized bovine enamel slabs, for 10 days. In the 1st phase, five participants followed protocol A: daily rinse with a Ca lactate (CaL, 150 mmol/L, 1 min), followed by F (NaF 12 mmol/L, 1 min). Other five participants followed protocol B: daily rinse only with F, while the remainders followed protocol C: no rinse (negative control). Appliances were removed from the mouth and one side of the palatal appliance was exposed to a daily erosive challenge (0.05 M citric acid, 90 s); the other side served as control (deionized water – no erosion). In the 2nd phase volunteers were crossed over to other protocol and in the 3rd phase volunteers received the remaining protocol not yet assigned. Specimens were evaluated for surface loss using an optical profilometer. Results Repeated-measures three-way ANOVA ( p = 0.009) and Tukey's test showed that CaL pre-rinse followed by NaF rinse significantly decreased surface loss of enamel when performed prior to an erosive challenge in comparison with the condition in which NaF only was used. Conclusions Pre-rinse with CaL may increase the protection exerted by NaF against erosive wear.

Plasma etching, during micro-fabrication processing is indispensable for fabricating MEMS structures. During theplasma processes, two major matters, charged ions and vacuum–ultraviolet (VUV) irradiation damage, take charge ofreliability degradation. The charged ions induce unwanted sidewall etching, generally called as “notching”, which causes degradation in brittle strength. Furthermore, the VUV irradiation gives rise to crystal defects on the etching surface. To overcome the problem, neutral beam etching (NBE), which use neutral particles without the VUV irradiation, has been developed. In order to evaluate the effect of the NBE quantitatively, we measured the resonance property of a micro-cantilever before and after NBE treatment. The thickness of damage layer (δ) times the imaginary part of the complex Young's modulus (Eds) were then compared, which is a parameter of surface damage. Although plasma processes make the initial surface of cantilevers damaged during their fabrication, the removal of that damage by NBE was confirmed as the reduction in δEds. NBE will realize a damage-free surface for microstructures.

Objective The study was performed to assess the risk of at-home and in-office bleaching procedures, and to recognise potential predictors for side effects. Design Multi-centre, questionnaire-based prospective study with follow-ups at around 14 days and around one year post-treatment. Setting General practices and university clinics during the years 2007-2009 in Scandinavia. Subjects Patients with tooth bleaching as part of the treatment plan. Results The prevalence of experienced tooth sensitivity at first follow-up was independent of bleaching procedure (at-home = 50.3% [n = 143]; in-office = 39.3% [n = 28]; p >0.05; 95% CI [OR]: 0.198-1.102) whereas prevalence of gingival irritation was higher after in-office treatment (at-home = 14.0%; in-office = 35.7%; p

Summary form only given. Electromagnetic FDTD-PIC simulation has seen significant advances recently: the availability of highly parallel GPU computing hardware has enabled high performance PIC simulation, while new algorithms for conformal boundary representation provide accurate simulation results in curved surface geometries. Here we combine these techniques to perform fast PIC simulations in complex metal RF structures, with a new algorithm for conformal boundary representation that includes the effects of Ohmic surface loss. Ohmic loss is a critical factor for accelerator and vacuum electronics applications in determining performance characteristics; however in simulations it is particularly sensitive to the accuracy of the boundary representation. Furthermore it is a dispersive effect that presents additional challenges in a time-domain simulation. The algorithm presented represents both the dispersive and dissipative electromagnetic properties of complex metal device structures, while maintaining compatibility with conventional particle simulation methods. We present results of GPUbased Conformal FDTD-PIC simulations, including Ohmic surface losses, which demonstrate second-order convergence of both frequency and Q. Examples of vacuum electronic device simulation will be used to show the utility of the code as a practical tool for rapid 3D device simulation and design, with a unique combination of speed and accuracy.

We present two algorithmic improvements to enhance accuracy for large-signal simulations of vacuum electronic amplifiers using the GPU-accelerated, 3D time-domain particle-in-cell code `Neptune'. A new conformal (cut-cell) geometry model with a new algorithm for Ohmic surface loss accurately predicts the dispersive and dissipative electromagnetic properties of complex metal device structures.

This study aimed to evaluate effectiveness of Phosphoryl-Oligosaccharides of Calcium (POs-Ca) added to apple juice on enamel erosion. Five juices were prepared by adding 0%, 0.5%, 1%, 1.5% or 2% POs-Ca to commercial apple juice, and subjected to Visual Analogue Scale (VAS) taste evaluation and pH and calcium/inorganic-phosphates analyses. To evaluate erosion, polished bovine enamel blocks were immersed in each juice for 5 or 60 min (n=20). Enamel surface loss (SL) and roughness (Ra) were also analyzed. VAS indicated acceptable taste for juices containing up to 1% POs-Ca. POs-Ca addition resulted in increased pH (3.61-3.88), calcium (0.95-25.10 mM), and inorganic-phosphate (1.77-20.44 mM). After 5 min, 0% juice resulted in significant erosion (p0.05). However even after 60 min, no significant increase was found in Ra and SL compared to water (control) for 1.5-2% juices (p0.05). Addition of 1-1.5% POs-Ca could significantly reduce enamel erosion by apple juice maintaining an acceptable taste.

Phosphorus-doped amorphous-silicon thin-film micromachined mechanical bridge resonators are processed at low temperatures (⩽110 °C) on glass substrates. The microelectromechanical structures are electrostatically actuated, and the resulting deflection is monitored optically. Resonance frequencies in the megahertz range are observed with quality factors up to 5000 when measured in vacuum. The energy dissipation processes in amorphous-silicon thin-film microbridges are discussed. The dominant intrinsic dissipation mechanism is surface loss.

The energy dependence of the partial cross sections of electron-impact dissociation of SF 6 into the neutral radicals SF, SF 2 and SF 3 is measured from the threshold to 200 eV. This measurement is accomplished by appearance mass spectrometry in a dual electron beam device. The dissociation products SF 4 and SF 5 are below the detection limit of the present system. The threshold energies for neutral dissociation into SF 3 , SF 2 and SF are measured to be 16.0, 19.5 and 22.0 eV respectively. The surface loss probability of each radical and the electron-impact nitrogen dissociation are examined to evaluate the relative dissociation cross section. However, the absolute cross section cannot be assigned for lack of the ionization cross sections for the SF x radicals.

Anterior tooth surface loss is a significant problem, ideally requiring early recognition, diagnosis and prevention of progression. However, when first noted it is often sufficiently advanced to warrant treatment. Management should be aimed at minimizing further tooth surface loss and frequently benefits from an integration of treatment procedures. The problems, aims of treatment, and relevant treatment modalities are discussed, and two illustrative cases presented.

Losses in superconducting planar resonators are presently assumed to predominantly arise from surface-oxide dissipation, due to experimental losses varying with choice of materials. We model and simulate the magnitude of the loss from interface surfaces in the resonator, and investigate the dependence on power, resonator geometry, and dimensions. Surprisingly, the dominant surface loss is found to arise from the metal-substrate and substrate-air interfaces. This result will be useful in guiding device optimization, even with conventional materials., Main paper: 4 pages, 4 figures, 1 table. Supplementary material: 4 pages, 2 figures, 1 table

Absolute cross sections for electron-impact dissociation of SiF4 from threshold to 300 eV are presented for formation of the neutral radicals SiF3, SiF2, SiF and Si. This measurement was accomplished with threshold-ionization mass spectrometry in a dual electron-beam device. The threshold energy for dissociation into each neutral radical was measured for the first time: 10.8 eV for SiF3, 13.9 eV for SiF2, 20.4 eV for SiF and 24.6 eV for Si. The surface loss probability of each radical and the electron-impact nitrogen dissociation were measured to calibrate the relative dissociation cross sections of SiF4. The magnitude of the cross section at its maximum is 0.68 * 10-20 m2 at 80 eV for SiF3, 0.16 * 10-20 m2 at 100 eV for SiF2, 0.019 * 10-20 m2 at 100 eV for SiF, and 0.0086 * 10-20 m2 at 120 eV for Si.

Objectives The primary objective was to determine the erosive effect of expectorated saliva, following chewing acidic gum, on enamel and dentine samples, using a non-acidic gum as a negative control. Secondary objectives were to determine the effect of brushing enamel and dentine samples and the effect of individual saliva pH and buffering. Design A single-centre, single-blind, placebo-controlled, two-way crossover study. Setting A clinical trial, involving healthy participants, undertaken at Bristol Dental School and Hospital. Methods Eight healthy participants expectorated saliva onto prepared enamel and dentine samples while chewing gum (strawberry flavoured acidic gum [active] or peppermint flavoured non-acidic gum [control]). Half of the enamel and dentine samples were brushed before measurement by contact profilometry. Main outcome measures Mean enamel and dentine erosion, with and without brushing and the relationship to salivary buffering. Results At 10 days, mean depth of surface loss from dentine samples (95% CI), following chewing of acid-containing gum and subsequent brushing, was −11.34 μm (2.22 μm) and from un-brushed dentine samples was −11.02 μm (1.71 μm). No significant erosion was noted for other groups. Conclusions Frequent chewers of acid-containing gums are susceptible to dentine erosion even in the presence of good salivary buffering. Enamel erosion was insignificant within the time constraints of the present study but warrants further investigation.

Objectives Alcoholic soft drinks have become increasingly popular and have high concentrations of citric acid and alcohol so might have the potential to cause dental erosion. This study aimed to investigate the erosive potential of alcopops on bovine enamel in vitro. Methods Six bovine upper incisors were prepared and sectioned to give six slabs per tooth, 4 mm × 4 mm each. Each slab was covered with nail varnish, leaving an exposed window (2 mm × 2 mm). Samples were immersed in 20 ml of each of the test solutions for 20 min, 1 h, and 24 h under gentle agitation (100 rpm). Enamel surface loss was determined using Quantitative Laser Fluorescence (QLF), Non-contact Profilometry (NCP) and Transverse Microradiography (TMR). Results Enamel loss occurred with all test drinks and the positive control (p

Objectives This in vitro study aimed to analyse the effect of a single application of TiF 4 and NaF varnishes and solutions to protect against dentin erosion. Methods Bovine root dentin samples were pre-treated with NaF-Duraphat varnish (2.26%F, pH 4.5), NaF/CaF 2 -Duofluorid varnish (5.63%F, pH 8.0), NaF-experimental varnish (2.45%F, pH 4.5), TiF 4 -experimental varnish (2.45%F, pH 1.2), NaF solution (2.26%F, pH 4.5), TiF 4 solution (2.45%F, pH 1.2) and placebo varnish (pH 5.0, no-F varnish control). Controls remained untreated. Ten samples in each group were then subjected to an erosive demineralisation (Sprite Zero, 4× 90 s/day) and remineralisation (artificial saliva, between the erosive cycles) cycling for 5 days. Dentin loss was measured profilometrically after pre-treatment and after 1, 3 and 5 days of de-remineralisation cycling. The data were statistically analysed by two-way ANOVA and Bonferroni's post hoc test ( p Results After pre-treatment, TiF 4 solution significantly induced surface loss (1.08 ± 0.53 μm). Only Duraphat reduced the dentin loss overtime, but it did not significantly differ from placebo varnish (at 3rd and 5th days) and TiF 4 varnish (at 3rd day). Conclusions Duraphat varnish seems to be the best option to partially reduce dentin erosion. However, the maintenance of the effects of this treatment after successive erosive challenges is limited.

The aim of this study was to determine if the abrasive effect on dentine of two commercially available toothpastes, known to vary in their in vitro abrasive levels, can be differentiated in an in situ model after 10 days, assessed by contact profilometry. This was a single centre, single blind, randomized, split mouth, two treatment, in situ study, in 34 healthy subjects, evaluating the abrasive effects of two marketed desensitizing toothpastes, (Colgate Sensitive Multi Protection toothpaste - C; Sensodyne Total Protection - S). Subjects wore bi-lateral, lower buccal appliances, each fitted with four dentine sections which were power brushed three times a day with the treatment regimen. Each subject received two toothpaste treatments for 10 days during the treatment period. Samples were measured at baseline and day 10 by contact and non-contact profilometry and day 5 by contact profilometry. Thirty-four subjects were included in the efficacy analysis. Results from contact profilometry showed statistically significant (P < 0.0001) dentine loss compared to baseline at day 5 and 10 for both pastes. At each time point, C showed statistically significantly greater dentine loss than S, P < 0.0001. After 10 days treatment, the difference in dentine loss between the pastes was 1.4 microm. The non-contact profilometry data showed similar trends. After 10 days of treatment, C showed statistically significantly greater dentine loss than S, with treatment difference of 0.9 microm, P = 0.0057. The methodology used has successfully differentiated between the abrasivity of the two pastes in respect of dentine surface loss over time in an in situ environment.

The surface loss function is an important quantity in the description of reflection electron-energy-loss spectroscopy (EELS) in near-specular geometry. In this paper, lattice-dynamics calculations of the surface energy-loss function associated with optical excitations in ionic-crystal slabs are performed. Test calculations are carried out for both NaF isolated films and NaF slabs onto a semi-infinite substrate. In the latter case, a continuum dielectric theory is used to describe the response of the substrate, emphasis being on long-wavelength optical phonons. We compare the results of the microscopic formulation of the surface loss function of the film with those deduced from the so-called dielectric theory, where a bulk-like dielectric response of the slab is assumed. The legitimacy of the use of a bulk response is a central question in applications of the dielectric theory to a very thin slab. It is shown that the latter provides a valid description of the surface energy-loss function for the wave vectors predominantly probed in EELS when the film thickness exceeds ~ 2 nm (about 10 atomic planes). For very thin, relaxed films (less than 8 atomic layers), the dielectric theory fails in producing the correct frequency positions of the surface energy-loss peaks; by contrast the intensities of the loss peaks are more accurately predicted.

A novel four-line, two-geometry (FLTG) measurement technique using coplanar waveguide structures is proposed for investigations on material characteristics from 1 GHz to 110 GHz. This measurement-based technique is simple and efficient when compared with other methods, and provides less uncertainty in the analysis, especially at mm-wave frequencies. The technique has been applied to the characterisation of coplanar lines on ceramic that were fabricated using photoimage able thick-film technology. The key outcome of the work is that it provides means of establishing surface loss at mm-wave frequencies.