Search

In high-pressure cold spray, it has been demonstrated that the enthalpy of the particle carrier gas has a significant effect on the propellant gas conditions and resulting particle impact velocities and temperatures. Through modeling and experimentation, this study demonstrates that in low-pressure cold spray, the enthalpy of the particle carrier gas has a minimal effect on the particle velocity; therefore, particle temperature can be controlled independently from particle velocity. This is a unique feature of downstream injection and a valuable tool when dealing with temperature sensitive substrates and particles. In this study, particle preheating was used to inject pure aluminum particles up to temperatures of 500 °C, about 80% of their melting temperature. This particle preheating was accomplished without clogging because of a novel particle preheater which eliminated the particles exposure to hot metal surfaces. It was found that even after substantial spray time, there was no evidence of wear or clogging. The preheating resulted in a DE increase of 3.6 times when compared to the injection of room temperature particles. [ABSTRACT FROM AUTHOR]

Species occur in sympatric assemblages, bound together by ecological relationships and interspecific interactions. Borneo and Sumatra host some of the richest assemblages of biota worldwide. The region, however, faces the highest global deforestation rates, which seriously threaten its unique biodiversity. We used a large camera trap dataset that recorded data for 70 terrestrial species of mammals and birds, to explore the drivers of regional species richness patterns. Using a multi‐scale, multivariate modelling framework which quantified the main environmental factors associated with patterns of biodiversity, while simultaneously assessing individual relationships of each species, we determined the ecological drivers of sampled biodiversity, and their contributions to community assemblages. We then mapped predicted species richness, evaluated the effectiveness of protected areas in securing biodiversity hotspots, performed gap analysis to highlight biodiverse areas lacking protection and compared our predictions with species richness maps produced by using IUCN range layers. Finally, we investigated the performance of each species as an indicator of sampled biodiversity. We demonstrate that biodiversity in Borneo and Sumatra is primarily affected by gradients of ecological and anthropogenic factors, and only marginally by topographic and spatial factors. In both islands, species are primarily associated with elevational gradients in vegetation and climate, leading to altitudinal zonation in niche separation as a major factor characterizing the islands' biodiversity. Species richness was highest in north‐eastern Borneo and in western Sumatra. We found that most predicted biodiversity hotspots are not formally protected in either island; only 9.2 and 18.2% of the modelled species richness occurred within protected areas in Borneo and Sumatra, respectively. We highlighted that our prediction for Borneo performed better than, and differed drastically from, the IUCN species richness layer, while for Sumatra our modelled species richness layer and the IUCN one were similar, and both showed low predictive power. Our analysis suggests that common and generalist carnivores are the most effective indicators of sampled biodiversity and have high potential as focal, umbrella or indicator species to assist multi‐species vertebrate conservation planning. Understanding existing drivers and patterns of biodiversity is critical to support the development of effective community conservation strategies in this rapidly changing region. [ABSTRACT FROM AUTHOR]

Iodinated contrast media (ICM) is one of the most frequently administered pharmaceuticals. In Canada, over 5.4 million computed tomography (CT) examinations were performed in 2019, of which 50% were contrast enhanced. Acute kidney injury (AKI) occurring after ICM administration was historically considered a common iatrogenic complication which was managed by screening patients, prophylactic strategies, and follow up evaluation of renal function. The Canadian Association of Radiologists (CAR) initially published guidelines on the prevention of contrast induced nephropathy in 2007, with an update in 2012. However, new developments in the field have led to the availability of safer contrast agents and changes in clinical practice, prompting a complete revision of the earlier recommendations. This revised guidance document was developed by a multidisciplinary CAR Working Group of radiologists and nephrologists, and summarizes changes in practice related to contrast administration, screening, and risk stratification since the last guideline. It reviews the scientific evidence for contrast associated AKI and provides consensus-based recommendations for its prevention and management in the Canadian healthcare context. This article is a joint publication in the Canadian Association of Radiologists Journal and Canadian Journal of Kidney Health and Disease, intended to inform both communities of practice. [ABSTRACT FROM AUTHOR]

Magnetic resonance cholangiopancreatography (MRCP) is used for the surveillance of primary sclerosing cholangitis (PSC) and its associated complications. The time interval gap for subsequent follow-up MRCP is variable depending on clinical practice patterns, therefore this study was done to assess the MRCP follow-up strategy used in our institution for screening PSC-associated hepatobiliary malignancies. This retrospective observational cohort included MRCP studies in adult patients, with clinical and radiological diagnosis of PSC over the past 15-year period between January 1, 2003 to December 31, 2018. The study population was grouped based on the presence and absence of PSC-associated malignancy. The frequency of MRCP follow-up was compared between the groups to look for MRI ordering trends in surveillance for PSC-associated complications. The overall median interval follow-up with MRCP was 14 months. The median follow-up interval in cases with PSC-associated malignancy was 6.0 months, compared to 13.1 months in the PSC group without malignancy (p 0.013). During the study period, the PSC-associated malignancy group had a median number of 7.5 scans, while the no malignancy group had a median number of 4 scans. Three patients (3/10, 30%) developed hepatobiliary malignancies within the first year of clinical diagnosis of PSC. The most common malignancy associated with PSC was cholangiocarcinoma (4.6%,7/10). Other PSC-associated malignancies included carcinoma gallbladder (1.3%,2/10), and hepatocellular carcinoma (0.6%,1/10). The median age of PSC associated malignancies was 56 (IQR 15) and higher compared to median age of PSC group without malignancies 46 (IQR 25.5), p 0.035. The median interval for subsequent follow-up MRCP in our study cohort was 14 months. One-third of PSC-associated hepato-biliary malignancies developed within the first year of clinical diagnosis of PSC, and the risk of PSC-associated hepato-biliary malignancy is constant after the first year. • Annual MRCP follow-up was the preferred practice pattern at our institution, with shorter interval gap triggered by recognition of disease deterioration. • The yield of detecting hepatobiliary malignancy in PSC surveillance is highest within the first year of diagnosis of PSC. • Incidence of PSC associated malignancies was higher in older patients when compared to patients with no malignancies. [ABSTRACT FROM AUTHOR]

We present an approach to characterize the relative saturation current density (Joe) and sheet resistance (RSH) of laser doped regions on silicon wafers based on rapid photoluminescence (PL) imaging. In the absence of surface passivation layers, the RSH of laser doped regions using a wide range of laser parameters is found to be inversely proportional to the PL intensity (IPL). We explain the underlying mechanism for this correlation, which reveals that, in principle, IPL is inversely proportional to Joe at any injection level. The validity of this relationship under a wide range of typical experimental conditions is confirmed by numerical simulations. This method allows the optimal laser parameters for achieving low RSH and Joe to be determined from a simple PL image. [ABSTRACT FROM AUTHOR]

The anterior alveolar ridge of the maxilla is a frequent site for pathology, most of it involving underlying bone and readily observable radiologically. Although much of this disease presents as well-defined unilocular radiolucencies arising adjacent to the apices of non-vital anterior teeth, thus being periapical radiolucencies of inflammatory origin (PRIO), a minority reflects more serious disease such as neoplasia. The most serious of the latter are malignancies, most frequently squamous cell carcinomas (SCCs). Although the majority of SCCs arise from the oral or nasal mucosa and secondarily invade the underlying bone, a proportion arise from epithelial remnants of odontogenesis within the alveolus. These need to be readily distinguished from other more common benign lesions, and also non-Hodgkin lymphomas (NHL). The latter has been reported arising with the alveolus in addition to their more usual nodal and extranodal sites. The rarer malignancies that could arise within the anterior maxilla are addressed in the text with particular reference to the 2017 edition of the World Health Organisation Classification of Head and Neck Tumours. [ABSTRACT FROM AUTHOR]

The conductivity mobility for majority carrier holes in compensated p-type silicon is determined by combined measurement of the resistivity and the net doping, the latter via electrochemical capacitance-voltage measurements. The minority electron mobility was also measured with a technique based on measurements of surface-limited effective carrier lifetimes. While both minority and majority carrier mobilities are found to be significantly reduced by compensation, the impact is greater on the minority electron mobility. The Hall factor, which relates the Hall mobility to the conductivity mobility, has also been determined using the Hall method combined with the capacitance-voltage measurements. Our results indicate a similar Hall factor in both compensated and noncompensated samples. [ABSTRACT FROM AUTHOR]

The concentration of boron-oxygen defects generated in compensated p-type Czochralski silicon has been measured via carrier lifetime measurements taken before and after activating the defect with illumination. The rate of formation of these defects was also measured. Both the concentration and the rate were found to depend on the net doping rather than the total boron concentration. These results imply that the additional compensated boron exists in a form that is not able to bond with the oxygen dimers, thus prohibiting the formation of the defect. This could be explained by the presence of boron-phosphorus complexes, as proposed in previous work. Evidence for reduced carrier mobilities in compensated silicon is also presented, which has implications for photoconductance-based carrier lifetime measurements and solar cell performance. [ABSTRACT FROM AUTHOR]

Imaging the band-to-band photoluminescence of silicon wafers is known to provide rapid and high-resolution images of the carrier lifetime. Here, we show that such photoluminescence images, taken before and after dissociation of iron-boron pairs, allow an accurate image of the interstitial iron concentration across a boron-doped p-type silicon wafer to be generated. Such iron images can be obtained more rapidly than with existing point-by-point iron mapping techniques. However, because the technique is best used at moderate illumination intensities, it is important to adopt a generalized analysis that takes account of different injection levels across a wafer. The technique has been verified via measurement of a deliberately contaminated single-crystal silicon wafer with a range of known iron concentrations. It has also been applied to directionally solidified ingot-grown multicrystalline silicon wafers made for solar cell production, which contain a detectible amount of unwanted iron. The iron images on these wafers reveal internal gettering of iron to grain boundaries and dislocated regions during ingot growth. [ABSTRACT FROM AUTHOR]

An existing technique for accurate measurement of iron in silicon, which was previously restricted to low injection and a narrow doping range, has been extended to arbitrary injection and doping levels. This allows contactless lifetime measurement techniques to be used for very sensitive and rapid iron detection under a wide range of conditions. In addition, an easily measured and unambiguous “fingerprint” of iron in silicon has been identified. It is based on the invariant nature of the excess carrier density at which the injection-dependent lifetime curves, measured before and after iron–boron pair dissociation, cross over. This characteristic crossover point lies in the narrow range of 1.4 to 2.0×10[sup 14] cm[sup -3], provided only that the boron concentration is below 5×10[sup 16] cm[sup -3]. To demonstrate the value of these techniques, they have been applied to photovoltaic-grade cast multicrystalline silicon wafers. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The ability to detect environmental cold serves as an important survival tool. The sodium channels NaV1.8 and NaV1.9, as well as the TRP channel Trpm8, have been shown to contribute to cold sensation in mice. Surprisingly, transcriptional profiling shows that NaV1.8/NaV1.9 and Trpm8 are expressed in nonoverlapping neuronal populations. Here we have used in vivo GCaMP3 imaging to identify cold-sensing populations of sensory neurons in live mice. We find that ~80% of neurons responsive to cold down to 1 °C do not express NaV1.8, and that the genetic deletion of NaV1.8 does not affect the relative number, distribution, or maximal response of cold-sensitive neurons. Furthermore, the deletion of NaV1.8 had no observable effect on transient cold-induced (≥5 °C) behaviors in mice, as measured by the cold-plantar, cold-plate (5 and 10 °C), or acetone tests. In contrast, nocifensive-like behavior to extreme cold-plate stimulation (-5 °C) was completely absent in mice lacking NaV1.8. Fluorescence-activated cell sorting (FACS) and subsequent microarray analysis of sensory neurons activated at 4 °C identified an enriched repertoire of ion channels, which include the Trp channel Trpm8 and potassium channel Kcnk9, that are potentially required for cold sensing above freezing temperatures in mouse DRG neurons. These data demonstrate the complexity of cold-sensing mechanisms in mouse sensory neurons, revealing a principal role for NaV1.8-negative neurons in sensing both innocuous and acute noxious cooling down to 1 °C, while NaV1.8-positive neurons are likely responsible for the transduction of prolonged extreme cold temperatures, where tissue damage causes pan-nociceptor activation. [ABSTRACT FROM AUTHOR]

The cold gas dynamic spraying process provides an advantageous solution to the deposition, and additive manufacturing, of metals. Namely, it provides a reduced reactive environment, simple operation, and high deposition rates. It is known that the deposition efficiency of the cold spray process can be substantially increased using helium instead of nitrogen as the process gas. However, the use of pure helium can be cost prohibitive and commercially available helium recovery systems constitute a major capital investment and cannot be used with portable systems. This work focuses on the development and use of a novel, in-line gas mixing system, designed to provide a blend of nitrogen and helium at any ratio. Deposits produced with different gas ratios are investigated through particle velocity measurements, deposition efficiency, coating porosity, and coating hardness. The experimental results show that helium, even in lower percentages, can have a significant effect on deposition efficiency and coating quality. From the results, a cost model is presented which, when provided experimental values and user costs, can be used to identify the nitrogen-helium ratio that will produce the lowest overall coating cost. [ABSTRACT FROM AUTHOR]

Purpose: The primary aim was to compare the early knee-specific functional outcome after articular surface mounted (ASM) navigation with non-navigated TKA. The secondary aims were to compare general physical and mental health improvement, patient satisfaction, and reliability of component alignment in the sagittal and coronal planes between ASM navigated TKA with that of non-navigated TKA.Methods: Prospective functional outcome and radiographic data were collect for 123 patients undergoing ASM navigation and 172 patients undergoing non-navigated TKA by a high volume single surgeon. Pre-operative and one-year Oxford knee score (OKS) and short form (SF-) 12 scores were collected. Patient satisfaction was also assessed at one year. Implant position was assessed on post-operative radiographs (alpha, beta, gamma, and sigma angles) by a blinded observer.Results: There was no significant difference for improvement in OKS, SF-12 physical or mental components, or satisfaction between the groups one year following surgery. The non-navigation group was significantly more likely to have outliers (greater than 3 degrees) in femoral varus/valgus coronal alignment [odds ratio (OR) 4.5, 95% confidence interval (CI) 1.0-20.7, p = 0.049] and for posterior tibial slope (OR 8.3, 95% CI 1.1-65.0, p = 0.03).Conclusions: ASM navigation significantly reduces the number of outliers for the femoral and tibial components when compared to conventional non-navigation alignment. However, the short-term functional outcome is not influenced by the surgical technique used. If the surgeon wants to reduce their number of outliers, then ASM navigation should be considered but the overall functional outcome in the short term is not influenced.Level Of Evidence: III Therapeutic investigation, retrospective cohort study. [ABSTRACT FROM AUTHOR]

We present experimental evidence for the impurity gettering effect of atomic layer deposited aluminium oxide (Al2O3) films on silicon wafers, during typical surface passivation activation at 425 °C. Iron was used as a model impurity in silicon to study the gettering effects. Dissolved iron concentrations were determined by carrier lifetime measurements, allowing the iron loss kinetics in silicon wafers with Al2O3 coatings to be monitored during annealing. The redistribution of iron to the surface layers and the sub-surface regions was examined by secondary ion mass spectrometry depth profiling. The results show that the atomic layer deposited Al2O3 films generate a strong gettering effect, removing 50% of the iron after 30min at 425 °C for a 160-µm thick silicon wafer. The iron reduction process is largely diffusion-limited in the initial stages. The gettering effect is caused by the accumulation of iron at the Al2O3/Si interface. [ABSTRACT FROM AUTHOR]

We present experimental evidence for the impurity gettering effect of atomic layer deposited aluminium oxide (Al2O3) films on silicon wafers, during typical surface passivation activation at 425 °C. Iron was used as a model impurity in silicon to study the gettering effects. Dissolved iron concentrations were determined by carrier lifetime measurements, allowing the iron loss kinetics in silicon wafers with (Al2O3) coatings to be monitored during annealing. The redistribution of iron to the surface layers and the sub-surface regions was examined by secondary ion mass spectrometry depth profiling. The results show that the atomic layer deposited (Al2O3) films generate a strong gettering effect, removing 50% of the iron after 30 min at 425 °C for a 160-µm thick silicon wafer. The iron reduction process is largely diffusion-limited in the initial stages. The gettering effect is caused by the accumulation of iron at the (Al2O3)/Si interface. [ABSTRACT FROM AUTHOR]

The article presents a study which evaluates whether the early functional outcome of total knee replacement (TKA) is influenced by the satisfaction TKA patients experienced during their hospital stay. The use of the Oxford knee score (OKS), the ten worst aspects of a hospital stay, and the study's limitation are discussed.

Titanium parts are ideally suited for aerospace applications due to their unique combination of high specific strength and excellent corrosion resistance. However, titanium as bulk material is expensive and challenging/costly to machine. Production of complex titanium parts through additive manufacturing looks promising, but there are still many barriers to overcome before reaching mainstream commercialization. The cold gas dynamic spraying process offers the potential for additive manufacturing of large titanium parts due to its reduced reactive environment, its simplicity to operate, and the high deposition rates it offers. A few challenges are to be addressed before the additive manufacturing potential of titanium by cold gas dynamic spraying can be reached. In particular, it is known that titanium is easy to deposit by cold gas dynamic spraying, but the deposits produced are usually porous when nitrogen is used as the carrier gas. In this work, a method to manufacture low-porosity titanium components at high deposition efficiencies is revealed. The components are produced by combining low-pressure cold spray using nitrogen as the carrier gas with low-cost titanium powder produced using the Armstrong process. The microstructure and mechanical properties of additive manufactured titanium components are investigated. [ABSTRACT FROM AUTHOR]

Rituximab is widely used for the treatment of non-Hodgkin lymphoma, being a key component in most therapeutic regimens. Administration of the intravenous (IV) formulation is lengthy and places a significant burden on health care resources and patient quality of life. A subcutaneous (sc) formulation that provides a fixed dose of rituximab is being examined in a number of studies. Results indicate that the pharmacokinetics are noninferior and response rates are comparable to those obtained with the IV formulation. Moreover, the sc formulation is preferred by patients and health care providers and reduces administration and chair time. Additional advantages include a lesser potential for dosing errors, shorter preparation time, reduced drug wastage, and fewer infusion-related reactions. Despite the success of the sc formulation, correct administration is needed to reduce administration-related reactions. By using a careful procedure, the sc formulation can be given safely and effectively, potentially reducing the burden on health care resources and improving quality of life for patients. [ABSTRACT FROM AUTHOR]

The 2016 annual meeting of the American Society of Hematology took place in San Diego, California, 3-6 December. At the meeting, results from key studies on the first-line treatment of follicular lymphoma were presented. Of those studies, key oral presentations included two analyzing data from the gallium study, which evaluated the efficacy and safety of obinutuzumab plus chemotherapy (G-chemo) compared with rituximab plus chemotherapy (R-chemo), followed, in responding patients with follicular lymphoma, by obinutuzumab or rituximab maintenance; results from the sabrina study, which evaluated the efficacy and safety of subcutaneous compared with intravenous rituximab; results of a cost-effectiveness analysis of first-line treatment with bendamustine and rituximab from a Canadian perspective; and results from the SAKK 35/10 study, which evaluated the safety and efficacy of rituximab plus lenalidomide compared with rituximab monotherapy. Our meeting report describes the foregoing studies and includes interviews with the Canadian investigators, plus commentaries by those investigators about the potential impact on Canadian practice. [ABSTRACT FROM AUTHOR]

Thick copper coatings have been envisioned as corrosion protection barriers for steel containers used in repositories for nuclear waste fuel bundles. Due to its high deposition rate and low oxidation levels, cold spray is considered as an option to produce these coatings as an alternative to traditional machining processes to create corrosion protective sleeves. Previous investigations on the deposition of thick cold spray copper coatings using only nitrogen as process gas on carbon steel substrates have continuously resulted in coating delamination. The current work demonstrates the possibility of using an innovative surface preparation process, forced pulsed waterjet, to induce a complex substrate surface morphology that serves as anchoring points for the copper particles to mechanically adhere to the substrate. The results of this work show that, through the use of this surface preparation method, adhesion strength can be drastically increased, and thick copper coatings can be deposited using nitrogen. Through finite element analysis, it was shown that it is likely that the bonding created is purely mechanical, explaining the lack of adhesion when conventional substrate preparation methods are used and why helium is usually required as process gas. [ABSTRACT FROM AUTHOR]

With no treatment standard having been established for relapsed and refractory follicular lymphoma, a number of therapeutic approaches are used in Canada. In patients who relapse early or who eventually become resistant to subsequent treatment, prognosis is poor, and new approaches are needed. A number of novel therapies are being examined in this setting, including monoclonal antibodies, immunoconjugates, immunomodulatory agents, and signal transduction inhibitors. With the body of evidence for those emerging therapies accumulating and the standard upfront treatment changing from rituximab and chop (cyclophosphamide-doxorubicin-vincristine-prednisone) or rituximab and CVP (cyclophosphamide-vincristine-prednisone) to bendamustine and rituximab, treatment decisions in the relapsed and refractory setting have become more complex. The choice of subsequent treatment must consider type of upfront treatment; duration of remission; and patient-related factors such as age, comorbidities, and treatment preferences. This paper summarizes the evidence for novel therapies and proposes recommendations for subsequent treatment options by remission duration after induction and maintenance. [ABSTRACT FROM AUTHOR]

In order to compliment the current interest in lesions affecting the face and jaws in Clinical Radiology, this overview addresses recent developments in the classification, nomenclature, clinical and radiological diagnosis, and outcomes of treatment of the most important and frequent lesions that present as radiolucencies on conventional radiography of the jaws. Although termed "benign" a significant proportion of each odontogenic neoplasm can recur after conservative surgery. Two diagnostic flowcharts take the clinician from the radiological presentation of a lesion in the jaw to an appropriate diagnosis. The recent advent of cone-beam computed tomography (CBCT) can enhance the quality of the diagnosis and preoperative assessment of such lesions. CBCT images of typical benign neoplasms, cysts, and other phenomena affecting the face and jaws are included. The relative period prevalences of the lesions, based on the most recent UK reports, are included. The importance to the radiologist of an emerging lesion of the jaws, the glandular odontogenic cyst, is discussed. [ABSTRACT FROM AUTHOR]

In cold gas dynamic spraying, the gas nature, process stagnation pressure and temperature, and the standoff distance are known to be important parameters that affect the deposition efficiency and coating quality. This investigation attempts to elucidate the effect of nozzle material on coatings produced using a downstream lateral injection cold spray system. Through experimentation, it is shown that the nozzle material has a substantial effect on deposition efficiency and particle velocity. It is proposed that the effects are related to complex interaction between the particles and the internal nozzle walls. The results obtained lead to the conclusion that during the particle/nozzle wall contact, a nozzle with higher thermal diffusivity transfers more heat to the particles. This heat transfer results in lower critical velocities and therefore higher deposition efficiencies, despite a noticeable reduction of particle velocities which is also attributed to particle-nozzle interactions. [ABSTRACT FROM AUTHOR]

We compare the recombination properties of three important types of multicrystalline silicon wafers for solar cells, namely conventionally-solidified p-type and n-type multicrystalline wafers, and also the recently developed ‘high performance’ p-type multicrystalline wafers. Three distinct regions of the wafers are examined in detail. These are the intra-grain regions, the grain boundaries, and the dislocation networks. The response of these regions to phosphorous gettering and hydrogenation are also characterised and compared. The electrical properties of intra-grain regions are assessed based on both the minority carrier lifetime and diffusion length. The recombination activities of grain boundaries are compared quantitatively in terms of their effective surface recombination velocities. The recombination behaviour of dislocations is evaluated qualitatively based on photoluminescence images. Our results show that the main performance limiting factors are likely to be recombination at crystal defects. Overall, grain boundaries in conventional p-type samples are more recombination active than those in high performance p-type and conventional n-type samples. The benefits of hydrogenation are most visible on n-type samples, leading to significant deactivation of most of the grain boundaries. As-grown grain boundaries and dislocations in high performance multicrystalline silicon tend not to be recombination active, and only become active after either gettering or hydrogenation. [ABSTRACT FROM AUTHOR]

The technology that is being developed in Sweden for the disposal of high level nuclear waste calls for storage of the waste in copper canisters, which are encapsulated in a bentonite buffer contained in drill holes in the floors of drifts (tunnels) in a granitic rock repository. A controversial issue has arisen during the development of this technology: that copper, when in contact with pure water under anoxic conditions corrodes and hence is not immune as previously believed. This issue is resolved in the present paper by deriving corrosion domain diagrams as a means of presenting the thermodynamics of the system in the clearest form possible, when assessing the immunity and activation of copper. [ABSTRACT FROM AUTHOR]

It has been observed that the method of substrate surface preparation can have a profound effect on the adhesion strength of cold-sprayed metallic coatings. In this investigation, pure aluminum powder was sprayed onto aluminum alloy substrates using cold spray. The substrates used in this work had undergone a variety of surface preparations to impart varying degrees of surface roughness. The pulsed waterjet technique was used to increase the substrates' surface roughness beyond what can be achieved using traditional grit blasting procedures. Surfaces prepared using pulsed waterjet resulted in substantial increases in the pure aluminum coating adhesion strength. This increase may be the result of increased mechanical anchoring sites available as well as their favorable geometries. It is hypothesized that compressive residual stress may also contribute to increased adhesion strength. [ABSTRACT FROM AUTHOR]

A study comparing bromodeoxyuridine (BrdU) and cyclin A as markers of cells in the S-phase in oral precancerous lesions was performed. These were also compared with the growth fraction (GF) as assessed by Ki-67. Biopsies of 15 lesions were obtained, presenting clinically as leukoplakia or erythroplakia of the lateral tongue or floor of mouth. Half of each biopsy was incubated in BrdU and routinely fixed and processed. Sequential sections from each block were cut and stained immunohistochemically with antibodies against the following proteins: BrdU, Ki-67 and cyclin A. Stained sections were quantified and the labelling indices (LI) expressed per 100 of the total nucleated cell population (%) and per millimetre basement length (/mm). The mean LI% for BrdU was 11.24% (SD 2.83), for cyclin A it was 12.76% (SD 3.88) and the GF% was 29.25% (SD 11.88). The mean LI/mm for BrdU was 40.93/mm (SD 11.88), for cyclin A it was 47.59/mm (SD 18.28) and the GF/mm was 110.72/mm (SD 49.30). The BrdU and cyclin A indices were significantly correlated with each other. In the more dysplastic cases, the cyclin A LI was quantitatively much larger than that for BrdU, suggesting that the protein was being overexpressed. It was concluded that as a tool to study the kinetic aspects of the cell cycle in dysplastic lesions cyclin A was limited by the fact that it is overexpressed. In minimally dysplastic lesions and normal epithelia, however, cyclin A may be a viable alternative to BrdU for the study of the S-phase. [ABSTRACT FROM AUTHOR]

There is a need for objective methods of assessment of oral epithelial precancerous lesions and reliable markers for the prediction of malignant change in these lesions. Cell proliferation was examined in 20 dysplastic lesions from the tongue and floor of mouth using bromodeoxyuridine (BrdU) and Ki 67, and a histological compartment analysis was performed. Half of a fresh biopsy from each case was incubated in BrdU for 15 mm. the other halt was routinely processed and used for Ki-67 analysis. Sections from each block were immunohisto chemically stained with antibodies against BrdU and Ki-67. Dysplasia was graded according to the method of Smith & Pindborg. The BrdU labelling index (LI) and the growth fraction (GF), assessed by the use of Ki-67, was quantified and expressed as units per millimetre basement membrane length (BL) and per 100 total nucleated cells (TNC). The mean LI/TNC was 10.87 (SD 3.65) and the mean LI/BL was 51.55 (SD 20.75). The mean GF/TNC was 26.66 (SD 17,78j and GF/BL was 157.07 (SD 125.84). The mean epithelial thickness was 229.09 μm (SD 104.73). The Ll/BL correlated with the atypia score and with the GF/BL. The progenitor compartment sizes also correlated with the atypia scores. The BrdU Labelling index provides a further objective measurement of oral epithelial dysplasia and the progenitor compartments were large, implying that basal cell hyperplasia is a significant component of the dysplasia. [ABSTRACT FROM AUTHOR]

Introduction: Although the independent effects of diabetes mellitus and obesity on total hip replacement (THR) outcomes have been widely studied, their combined effect remains uncharacterised. This study aimed to assess the influence of diabesity on primary THR operative outcomes. Materials and methods: A retrospective study was performed comparing the outcomes of patients with diabesity (diabetes mellitus and obesity [BMI ≥ 30]) with a control cohort after primary THR using an established arthroplasty database. Data were collected pre-operatively and 12 months post-operatively, including Oxford Hip Score (OHS), EuroQol 5-dimensions (EQ5D), post-operative satisfaction and complication rates. Results: 2323 THRs were analysed, of which 94 (4%) had diabesity. Diabesity was independently associated with significantly worse OHS improvement post-operatively (− 1.85 points, 95% CI − 2.93 to − 0.76, p = 0.001). This reduction in addition to the independent effect of obesity (− 0.69 points, 95% CI − 1.18 to − 0.21, p = 0.005) resulted in an overall 2.54 point OHS reduction for patients with diabesity. Diabesity was not associated with EQ5D score change or post-operative satisfaction. Diabesity was independently associated with a worse pre-operative EQ5D score (−0.08 points, 95% CI −0.12 to −0.03, p = 0.002). When combining the associated risk of obesity (Odds Ratio (OR) 1.71, 95% CI 1.15–2.54, p = 0.008) with the superadded effect of diabesity (OR 2.37, 95% CI 1.19–4.71, p = 0.014) the rate of superficial wound infection post-operatively was significantly increased (OR 4.05, 95% CI 1.38–11.95). Obesity was associated with a significantly increased risk of deep infection (OR 3.67, 95% CI 1.55–8.68, p = 0.003), but no additive effect of diabetes was found. Conclusions: Diabesity confers a superadded effect over established associations between THR outcomes and obesity and diabetes individually. Patients with diabesity experience worse improvement in hip-specific functional outcome, worse post-operative quality of life, and an increased risk of superficial and deep wound infection following THR. [ABSTRACT FROM AUTHOR]

Background: Approximately 10% to 20% of patients with joint arthroplasties are golfers. The aim of this study was to assess if being a golfer is associated with functional outcomes, satisfaction or improvement in quality of life (QoL) compared to non-golfers following total knee arthroplasty. Methods: All patients undergoing primary total knee arthroplasty (TKA) over a one-year period at a single institution were included with one-year postoperative outcomes. Patients were retrospectively followed up to assess if they had been golfers at the time of their surgery. Multivariate linear regression analysis was performed to assess the independent association of preoperative golfing status on postoperative function and health-related outcomes. Results: The study cohort consisted of a total of 514 patients undergoing TKA. This included 223 (43.3%) male patients and 291 (56.7%) female patients, with an overall mean age of 70 (SD 9.5) years. The preoperative Oxford Knee Score (OKS) was significantly higher in golfers when adjusting for confounders (Diff 3.4 [95% CI 1 to 5.8], p = 0.006). There was no difference in postoperative outcomes between golfers and non-golfers. There was however a trend towards a higher Forgotten Joint Score (FJS) in the golfers (difference 9.3, 95% CI − 0.2 to 18.8, p = 0.056). Of the 48 patients who reported being golfers at the time of their surgery, 43 (89.6%) returned to golf and 88.4% of those were satisfied with their involvement in golf following surgery. Conclusions: Golfers had better preoperative and equal postoperative knee specific function compared to non-golfers. The majority of golfers returned to golf by one year and were satisfied with their involvement in the game. Level of evidence: III. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to identify threshold values in the post-operative Oxford knee score (OKS) and change in the score for achievement of specific patient expectations and satisfaction, and whether failure to meet specific patient expectations influenced the rate of satisfaction after total knee arthroplasty (TKA). Methods: Prospectively complied data for 322 primary TKA were used. Patient demographics, and pre- and post-operative (1 year) OKS, and expectation fulfilment were collected. Patient satisfaction was also assessed 1 year post-operatively. Results: Patient pre-operative expectations varied in prevalence and differed according to gender, age, and severity of knee symptoms according the OKS. Fulfilment of patient expectations was variable and was dependent upon the specific expectation; the majority of patients achieved their expectation of pain relief and improved ability to walk (>70 %), however, few fulfilled their expectation to kneel or squat (<25 %). The threshold according to the post-operative OKS at which these expectations were achieved varied by more than ten points, ranging from ≥31 for pain relief to ≥42 for kneeling. Failure to fulfil patient expectations, for 15 of the 17 assessed, significantly increased the risk of dissatisfaction at 1 year ( p < 0.05). Conclusion: The post-operative OKS can be used to predict the point at which the greatest proportion of patient expectations is achieved. Some expectations, however, are rarely fulfilled after a TKA and patients should be made aware of this pre-operatively which may improve their satisfaction post-operatively. Level of evidence: Retrospective comparative study, Level III. [ABSTRACT FROM AUTHOR]

Purpose: To report the functional outcome, implant survival, and patient mortality after mega prosthetic distal femoral arthroplasty according to the surgical indication. Methods: A prospective database was compiled for 45 consecutive patients undergoing distal femoral arthroplasty, of which 26 had fractures of the distal femur (group 1) and 19 underwent revision of a total knee arthroplasty (group 2). There were 17 males and 28 females with a median age of 74.5 years. Short form (SF)-12 scores were recorded pre-operatively (before the fracture or revision) and 1 year post-operatively, at which point a Toronto Extremity Salvage Score (TESS) was also obtained. Length of hospital stay and return to place of domicile was obtained from the hospital database. Mortality status was obtained from the General Register Office for Scotland. No patient was lost to follow-up. Results: The 1-year physical (52.4) and mental (63.4) components of the SF-12 score and the TESS (70.5 %) did not significantly differ between the groups (n.s.). The fracture group, however, had a longer length of stay (8 vs. 19 days, p = 0.001) and were also less likely to return to their original domicile (odds ratio 9.5, p = 0.02). The overall implant survival rate was 85 % at 5 years, which was worse for the fracture group (80 vs. 90 %, n.s.). The 5-year mortality rate for the revision group was 17 %, whereas the fracture group demonstrated a greater mortality rate of 43 % (n.s.). Conclusion: The functional outcome, revision rate, and mortality of patients undergoing distal femoral arthroplasty for non-tumour reasons are not influenced by indication, but patients undergoing surgery for fractures of the distal femur have a longer length of stay and are less likely to return home. Distal femoral arthroplasty should be considered as a management option for non-tumour salvage procedures of the distal femur. Level of evidence: Retrospective comparative study, Level III. [ABSTRACT FROM AUTHOR]

Objective: We prospectively determined islet autoantibody status in children presenting with diabetes to a single UK region in relation to ethnicity. Design: 316 (68.0% non-white) children presenting with diabetes between 2006 and 2013 were tested centrally for islet cell autoantibodies (ICA) and glutamic acid decarboxylase autoantibodies (GAD-65) at diagnosis, and if negative for both, tested for insulin autoantibodies (IAA). The assay used to measure GAD-65 autoantibodies changed from an in-house to a standardised ELISA method during the study. Results: Even with use of the standardised ELISA method, 25.8% of children assigned a diagnosis of type 1 diabetes still tested negative for all three autoantibodies. 30% of children assigned a diagnosis of type 2 diabetes were autoantibody positive, and these had the highest glycated haemoglobin (HbA1c) levels at 12 months follow-up compared with other groups (p value for analysis of variance <0.001), although the sample size was small. Autoantibody positivity was similar between non-white and white children regardless of assay used (60.0% (n=129) vs 56.4% (n=57), X²=0.9, p=0.35), as was mean GAD-65 autoantibody levels, but fewer non-white children had two or more autoantibodies detectable (13% (n=28) vs 27.7% (n=28), X² = 12. 1, p=0.001). Conclusions: Islet autoantibody positivity was associated with a more severe phenotype, as demonstrated by poorer glycaemic control, regardless of assigned diabetes subtype. Positivity did not differ by ethnic group. [ABSTRACT FROM AUTHOR]

Virtually nothing in nature is uniform. Observed at the right scale, most entities are clustered rather than evenly distributed, spatially and temporally, and this applies across domains from the distribution of matter in the universe, to habitats across the Earth's surface, and to energy in the landscape. Patchiness means organisms cannot carve out even territories. Instead, their shape and size depends on the dispersion of materials needed for survival and reproduction. This fundamental feature of life is intrinsically understood in ecology, for example, in the ideal free distribution and optimal foraging theory, and is represented in the anatomy as well as behaviour of organisms via the structures and strategies for moving, finding and capturing these patchy resources. But perhaps most striking of all is the role of patchiness in facilitating the formation of social groups - of societies. The resource dispersion hypothesis ( RDH) suggests that where resources are dispersed and rich enough, multiple individuals can collapse into groups that share the same space at little cost to each other. Cooperation may be absent, but sociality is favoured nevertheless. Thirty years after the origin of the hypothesis, we review the accumulating models, critiques, evidence and experiments, concluding that RDH is a pervasive feature of animal spacing patterns across a wide range of species, taxonomic groups and ecosystems. In the spirit of the original objective of the Huxley Reviews to 'suggest and inspire research that will improve our knowledge in the future', we also take the opportunity to consider wider implications of the RDH. If we live and evolved on a patchwork planet, then we should expect broader effects. Indeed, we suggest that the RDH has played an important role in the evolution of cooperation, biodiversity, behaviour and, not least, in the social organization of humans in our evolutionary past and today. [ABSTRACT FROM AUTHOR]

Highlights: [•] Recycled water in food production could benefit environmental and commercial interests. [•] However possible consumer rejection may damage brands. [•] Hedonic and emotional responses to meatballs purported to be made with recycled water were tested. [•] Acceptance and positive emotional responses to tasting were observed. [•] Affective and emotional responses aid understanding of foods associated with perceived risk. [ABSTRACT FROM AUTHOR]

Peri-urban floodplains are an important interface between developed land and the aquatic environment and may act as a source or sink for contaminants moving from urban areas towards surface water courses. With increasing pressure from urban development the functioning of floodplains is coming under greater scrutiny. A number of peri-urban sites have been found to be populated with legacy landfills which could potentially cause pollution of adjacent river bodies. Here, a peri-urban floodplain adjoining the city of Oxford, UK, with the River Thames has been investigated over a period of three years through repeated sampling of groundwaters from existing and specially constructed piezometers. A nearby landfill has been found to have imprinted a strong signal on the groundwater with particularly high concentrations of ammonium and generally low concentrations of nitrate and dissolved oxygen. An intensive study of nitrogen dynamics through the use of N-species chemistry, nitrogen isotopes and dissolved nitrous oxide reveals that there is little or no denitrification in the majority of the main landfill plume, and neither is the ammonium significantly retarded by sorption to the aquifer sediments. A simple model has determined the flux of total nitrogen and ammonium from the landfill, through the floodplain and into the river. Over an 8 km reach of the river, which has a number of other legacy landfills, it is estimated that 27.5 tonnes of ammonium may be delivered to the river annually. Although this is a relatively small contribution to the total river nitrogen, it may represent up to 15% of the ammonium loading at the study site and over the length of the reach could increase in-stream concentrations by nearly 40%. Catchment management plans that encompass floodplains in the peri-urban environment need to take into account the likely risk to groundwater and surface water quality that these environments pose. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to identify the minimal clinically important difference (MCID) in the Oxford knee score (OKS) and Short Form (SF-) 12 score after total knee arthroplasty (TKA). Methods: Prospective pre-operative and 1 year post-operative OKS and SF-12 scores for 505 patients undergoing a primary TKA for osteoarthritis were collected during a one-year period. Patient satisfaction with their (1) patient relief and (2) functional outcome was used as the anchor questions. Their response to each question was recorded using a 5-point Likert scale: excellent, very well, well, fair, and poor. Simple linear regression was used to calculate the MCID for improvement in the OKS and physical component of the SF-12 score according to the level of patient satisfaction with their pain relief and function. Results: The OKS improved by 15.5 (95 % CI 14.7-16.4) points and the SF-12 physical component score improved by 10.1 (95 % CI 9.1-11.2) points for the study cohort. The level of patient satisfaction with their pain relief and function correlated with the improvement in the OKS ( r = 0.56; p < 0.001, and r = 0.56; p < 0.001) and the physical component of the SF-12 score ( r = 0.51; p < 0.001, and r = 0.60; p < 0.001), respectively. The MCID for the OKS was 5.0 (95 % CI 4.4-5.5) and 4.3 (95 % CI 3.8-4.8) points and for the physical component of the SF-12, it was 4.5 (95 % CI 3.9-5.2) and 4.8 (95 % CI 4.2-5.4) points for pain relief and function, respectively. Conclusion: The MCID identified for the OKS and SF-12 physical component score after TKA is the best available estimate and can be used to power studies and ensure that a statistical difference is also recognised by a patient. Level of evidence: Retrospective diagnostic study, Level III. [ABSTRACT FROM AUTHOR]

In this work, projection method with degenerated Kernel and its properties are used to solve linear Fredholm Integro-Differential integral equations (LFIDE). The kernel in the equation are degenerated and convert to matrix in which each equations are integrated over the interval [0, 1] to produce the elements for obtaining the Eigen value. It approaches linear Fredholm Integro-Differential equations in a manner that gives the solution in an exact form and not in a series form, the algorithm is simple and effective, and could also provide an accurate approximate solution. [ABSTRACT FROM AUTHOR]

An odontogenic epithelial cell line. ROE-2B, was established by propagating disaggregated immature, unmineralized maxillary third molar tooth germs from 11-day old Sprague-Dawley rats on a feeder layer of Mitomycin-C treated NIH 3T3 embryonic mouse fibroblasts. The cell line has been maintained for more than 6 months and through 7 passages. Light microscopic examination of cells revealed colonies with epithelial morphology. Electron microscopic examination confirmed the epithelial nature by the demonstration of tonofilaments, desmosomes and basal lamina. Cells were also shown to have secretory vacuoles. an abundance of granular endoplasmic reticulum, free ribosomes, Golgi complex and mitochondria. Surface activity in the form of pseudopodia-like projections and micropinocytosis were noted. Epithelial cells forming keratin were demonstrated by a positive histochemical reaction with Rhodanile Blue. Immunohistochemical studies showed a positive reaction for CAM 5.2 indicating that the ROE-2B cells express the cytokeratins of simple or glandular epithelia. The ROE-2B cell line will be useful for studies on in vitro biological behaviour of odontogenic epithelial cells, and may allow the establishment of in vitro models of odontogenic tumours. [ABSTRACT FROM AUTHOR]

The origin of passivity, as viewed from the Point Defect Model, is presented in terms of the phase space analysis of the rate law for the growth of passive films. It is shown that passivity is due to the formation of a metastable oxide and hence, the occurrence of passivity is a kinetic phenomenon, in which the rate of film growth of the oxide at the metal/barrier layer interface into the metal at zero barrier layer thickness must exceed the rate of barrier layer dissolution at the barrier layer/solution (bl/s) interface, in order for the barrier layer to exist. If this relationship does not hold, the barrier layer disappears and the surface becomes depassivated. Depassivation is illustrated with respect to transpassive dissolution, acid depassivation, pitting corrosion, flow assisted corrosion, impingement attack, resistive depassivation and other phenomena. The theory also leads to the development of Kinetic Stability Diagrams (KSDs), in which the potential for depassivation is plotted against pH to define regions of depassivation and passivation, so that regions in potential versus pH space can be defined within which passive films may exist as protective, metastable entities. The author offers these diagrams as kinetically inspired alternatives to the classical Pourbaix diagrams. One form of depassivation that occurs at highly localised regions on a metal surface is pitting corrosion. The theory for pitting is now highly developed and certain aspects of the subject are reviewed here. It is argued that the theory of pitting is sufficiently well established that the deterministic prediction of pitting damage is practical, in many systems. The theory is illustrated here with respect to the pitting of Type 403 stainless steel (SS), which is used extensively for the manufacture of low pressure steam turbines in steam cycle systems for the generation of electrical power. [ABSTRACT FROM AUTHOR]

Vaccines that induce T cells, which recognize conserved viral proteins, could confer universal protection against seasonal and pandemic influenza strains. An effective vaccine should generate sufficient mucosal T cells to ensure rapid viral control before clinical disease. However, T cells may also cause lung injury in influenza, so this approach carries inherent risks. Here we describe intranasal immunization of mice with a lentiviral vector expressing influenza nucleoprotein (NP), together with an NFκB activator, which transduces over 75% of alveolar macrophages (AM). This strategy recalls and expands NP-specific CD8+ T cells in the lung and airway of mice that have been immunized subcutaneously, or previously exposed to influenza. Granzyme B-high, lung-resident T-cell populations persist for at least 4 months and can control a lethal influenza challenge without harmful cytokine responses, weight loss, or lung injury. These data demonstrate that AM can be harnessed as effective antigen-presenting cells for influenza vaccination. [ABSTRACT FROM AUTHOR]

Background: There is conflicting evidence as to whether diabetes mellitus influences the functional outcome and patient satisfaction after a total knee replacement (TKR). The aim of this study was to assess the effect of diabetes upon the Oxford knee score (OKS), short form (SF)-12, and patient satisfaction after TKR. Methods: Prospective pre- and post-operative (one year) OKS and SF-12 scores for 2389 patients undergoing primary TKR were compiled, of which 275 (12%) patients suffered with diabetes. Patient satisfaction was assessed at one year. Results: Patients with diabetes were more likely to have a greater level of comorbidity (p < 0.001), and a worse pre-operative OKS and SF-12 score (p < 0.02), compared to those patients without diabetes. Diabetes was not a significant (p > 0.41) independent predictor of post-operative OKS or the SF-12 physical score on multivariable analysis. Although, factors more prevalent within the diabetic cohort (heart disease, vascular disease, liver disease, anaemia, depression, back pain, worse pre-operative OKS and SF-12 score) were found to be independent predictors of post-operative OKS and SF-12 physical score. Interestingly, diabetes was associated with a significantly greater improvement in mental wellbeing (SF-12 mental component), which was confirmed on multivariable analysis. Patient satisfaction was not influenced by a concomitant diagnosis of diabetes (p = 0.57). Conclusion: The outcome of TKR as assessed by the OKS, SF-12, and overall patient satisfaction rates are not influenced by diabetes per se, although factors more prevalent within this population result in a worse postoperative outcome. Level of evidence: prospective cohort study, level III. [ABSTRACT FROM AUTHOR]

Foodborne disease outbreaks associated with fresh fruits and vegetables have been increasing in occurrence worldwide. Canada has one of the highest per capita consumption rates of fresh fruits and vegetables in the world. In this article, we review the foodborne disease outbreaks linked to produce consumption in Canada from 2001 through 2009. The 27 produce-related outbreaks included an estimated 1,549 cases of illness. Bacterial infection outbreaks represented 66% of the total. Among these, Salmonella was the most frequent agent (50% of outbreaks) followed by Escherichia coli (33%) and Shigella (17%). Cydospora cayetanensis was the only parasite detected and was associated with seven outbreaks. Among the foodborne viruses, only hepatitis A was implicated in two outbreaks. The food vehicles most commonly implicated in outbreaks were leafy greens and herbs (26% of outbreaks), followed by seed sprouts (11%). Contamination sources and issues related to the future control of fresh produce-related foodborne disease outbreaks also are discussed. [ABSTRACT FROM AUTHOR]

Abstract: The effect of cold spray coating in inducing residual stresses in the substrate and its effect on delaying crack initiation under cyclic loading have been studied on Al5052 alloy specimens. Different sets of Al5052 specimens have been coated with pure Al and Al7075 feedstock powder, using a low-pressure cold spray coating technique. Some sets of specimens were grit blasted (GB) before coating. The microstructural evolution of the substrate after coating and the fatigue behavior of the coated structure have been studied. In order to obtain the fatigue S–N diagram for each set, as-received and coated specimens with and without preceding GB treatment have been tested in a load-controlled condition. X-ray diffraction has been used to measure the residual stresses both in the deposited materials and the substrates. The results are discussed to highlight the effect of this emerging surface treatment on the characteristics of the treated material. Compressive residual stresses, which led to appreciable increase in the fatigue life, have been observed in all the coated sets. The results indicate that the fatigue strength was significantly improved up to 30% in the case of Al7075 coatings. The results show a strong dependency of the fatigue strength on the deposited material and the spray parameters. [Copyright &y& Elsevier]

The African wild dog Lycaon pictus is endangered, with anthropogenic impacts, pack size dynamics and competing predators explaining its decline. Relative to solar and lunar events, analysis of diel activity in two parapatric Zimbabwean populations revealed behavioural plasticity in response to human activity. In Hwange, human presence was low; in Nyamandlovu, human presence and persecution were high. In both populations, Lycaon frequently hunted by moonlight, with 3-4 lux of light restricting nocturnal hunting to 13 days/lunar month. With diurnal hunts commencing at 'civil twilight begin' and ending at 'astronomical twilight end', light intensity was confirmed as a limiting factor. Nyamandlovu dogs exhibited behavioural plasticity, demonstrated by scattered rather than clumped organization when at rest, and masked the zeitgeber by utilizing evenings and moonlight for more days under suboptimal light conditions than did Hwange dogs. Significantly, different allocation of morning, evening and moonlight hunts between Hwange (47%, 36%, 15%) and Nyamandlovu (28%, 31%, 41%), reduced the temporal potential for human encounter by 64%, but increased this potential for hyaena and lion encounters by 70% and 37%, thus highlighting the trade-off of this switch. Finally, we tentatively conclude that the cue masking the 'zeitgeber' is risk, rather than gain related, and could be seen as an evolutionary 'emergency exit', the understanding of which is important to conservation in landscapes that are increasingly dominated by people. [ABSTRACT FROM AUTHOR]

Abstract: This paper introduces a photoluminescence-based technique for determining the acceptor concentration in silicon wafers by measuring the formation rate of iron-acceptor pairs. This rate is monitored by band-to-band photoluminescence in low injection, the intensity of which is proportional to the carrier lifetime. The technique is demonstrated with an iron-implanted float zone silicon wafer, heavily compensated Czochralski-grown silicon wafers with iron contamination and an upgraded metallurgical-grade silicon wafer containing natural iron. The FeB pairing rates measured on the float zone sample at different temperatures yield an activation energy that correlates closely to the migration enthalpy associated with the diffusion of iron in silicon, confirming that the changes observed are indeed due to iron-acceptor pairing. The acceptor concentrations determined in the strongly compensated Czochralski-grown silicon wafers and the upgraded metallurgical silicon wafer using the new technique were consistent with the values obtained by the Quasi-Steady-State Photo Conductance lifetime measurement technique and inductively coupled plasma mass spectroscopy respectively, thus proving its usefulness. [Copyright &y& Elsevier]