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Inclusions of platinum-group minerals (PGM) within alluvial isoferroplatinum nuggets from the Freetown Peninsula, Sierra Leone, are aligned with their shape determined by the structure of their host. The edges of the majority of the inclusions lie at 0°, 45° or 90° to external crystal edges of the nugget which shows that the inclusions are not randomly oriented earlier minerals incorporated within their host. The inclusions are later infills, probably formed at the surface of the nugget during growth and subsequently enclosed by the growing nugget. PGM on the present surface of the nugget represent the last stage of this partnership. A single nugget containing abundant inclusions is described here but similar features are observed in other nuggets from the same area. The inclusions contain laurite (RuS2), irarsite–hollingworthite (IrAsS–RhAsS), Pd–Te–Bi–Sb phases, Ir-alloy, Os-alloy, Pd-bearing Au, an Rh–Te phase, Pd–Au alloy and Pd–Pt–Cu alloy. PGM found on the nugget surface include laurite, irarsite and cuprorhodsite (CuRh2S4). The Pd–Te–Bi–Sb phases may include Sb-rich keithconnite (Pd20S7) and compositions close to the kotulskite–sobolevskite solid-solution series (PdTe–BiTe). Textural evidence suggests that formation of the nuggets began with the isoferroplatinum host and the voids were filled starting intergrowths of laurite and irarsite–hollingworthite with both laurite and irarsite–hollingworthite often showing compositional zonation and each of them replacing the other. Filling of the voids probably continued with Pd-Cu-bearing gold, Sb-rich keithconnite (Pd,Pt)20.06(Te,Sb,Bi)6.94, keithconnite, telluropalladinite Pd9(Te,Bi)4, RhTe and finally Ir-alloy and then Os-alloy. The nuggets are thought to be neoform growths in the organic- and bacterial-rich soils of the tropical rain forest cover of the Freetown intrusion. The mineralogical assemblage in the layered gabbros of the intrusion has been previously shown to differ from the alluvial assemblage in the rivers and these inclusions, not seen in Pt3Fe in the unaltered rocks, add a further item to the catalogue of differences.
Highly anomalous platinum-group element (PGE) concentrations in the podiform chromitites at the Cliff and Harold's Grave localities in the Shetland ophiolite complex have been well documented previously. The focus of this study is alluvial platinum-group minerals (PGM) located in small streams that drain from the PGE-rich chromitites. The placer PGM assemblage at Cliff is dominated by Pt-arsenides (64%) and Pd-antimonides (17%), with less irarsite–hollingworthite (11%) and minor Pd-sulfides, Pt–Pd–Cu and Pt–Fe alloys and laurite. Gold also occurs with the PGM. Alluvial PGM have average sizes of 20 µm × 60 µm, with sperrylite the largest grain identified at 110 µm in diameter, matching the range reported for the primary PGM in the source rocks. The placer assemblage contains more Pt-bearing and less Pd-bearing PGM compared with the rocks. The more resistant sperrylite and irarsite–hollingworthite grains which are often euhedral become more rounded further downstream whereas the less resistant Pd-antimonides which are commonly subhedral may become striated and etched. Less stable phases such as Pt- and Pd-oxides and other Ni-Cu-bearing phases located in the rocks (i.e. Ru-pentlandite, PtCu, Pd–Cu alloy) are absent in the placer assemblage. Also the scarce PGM (PdHg, Rh- and Ir-Sb) and Os in the rocks are absent. At Harold's Grave only three alluvial PGM (laurite, Ir, Os) and Au were recovered reflecting the limited release of IPGM from chromite grains in the rocks. In this cold climate with high rainfall, where erosion dominates over weathering, the PGM appear to have been derived directly from the erosion of the adjacent PGE-rich source rocks and there is little evidence of in situ growth of any newly formed PGM. Only the presence of dendritic pure Au and Pd-, Cu-bearing Au covers on the surface of primary minerals may indicate some local reprecipitation of these metals in the surficial conditions.
Heavy mineral concentrates from rivers and river terraces near York, Freetown Peninsula, Sierra Leone have been examined for their platinum-group mineral (PGM) content. The alluvial PGM are 0.1 to 1.5 mm in size and include Cu-bearing isoferroplatinum (Pt3Fe) and disordered Pt3–xFe (x ≤ 0.38), tulameenite (Pt2FeCu), hongshiite (PtCu), cooperite–vysotskite (PtS–PdS), laurite (RuS2), erlichmanite (OsS2), Os-Ir alloy, Os-Ru alloy and native copper.
Are the alluvial nuggets primary or a neoformation? Comparison of the PGM mineralogy of fresh rocks, weathered rocks and the saprolite, with the alluvial suite shows strongly contrasting features highlighted by the mineral assemblage. Cooperite in the fresh rocks is rare in the alluvium whilst Pt-Fe alloys become more abundant. Oxidized PGM are a feature only of the weathering process and disordering of the Pt-Fe alloys develops during weathering. Palladium is much less abundant in the alluvial suite than in the primary minerals whereas Cu, present as Cu-sulfides in the fresh rocks, occurs in the alluvium as a minor component of the Pt-Fe alloys and as hongshiite alteration to the Pt-Fe alloys. The size difference is striking; the primary mineralogy is micrometre-sized whereas the alluvial PGM are three orders of magnitude larger. Delicate PGM with alteration textures are seen only in the weathered rocks whilst delicate dendritic PGM are reported only from the alluvial suite. An organic coating to the alluvial PGM may be indicative of an organic or bacterial involvement. Some alluvial PGM occur in a drainage basin devoid of outcrops of PGE-bearing horizons.
Together these contrasting features of the primary and placer PGM support the proposal that the Freetown nuggets developed as a result of breakdown of the primary PGM during weathering, movement of the PGE in solution, and growth of new PGM in placers with a different mineral assemblage, mineralogy and mineral chemistry.
Resonant Inductive Coupling Wireless Power Transfer (RIC-WPT)is a key technology to provide an efficient wireless power channel to consumer electronics, biomedical implants and wireless sensor networks. Due to its non radiative nature, RIC Wireless Power Transfer has been considered safe for humans when adhered to magnetic health radiation safety regulations (Christ et al., 2013), unveiling a large range of potential applications in which this technology could be used. However, current deployments are limited to point-to-point links and do not explore the capabilities of Multi-Node RIC-WPT Systems. In such a system, the multi-path relaying effect between different nodes could effectively improve the performance of the link in terms of power transferred to the load and power transfer efficiency. However, depending on the impedance and resonant frequency of the nodes that generate the multi-path effect, these nodes could also act as interfering objects, therefore (a) making the transmitter and/or receiver act as a pass-band filter and (b) losing part of the transmitter magnetic field through coupling to the interfering node. In this paper, a circuit-based analytical model that predicts the behavior of a Multi-Node Resonant Inductive Coupling link is proposed and used to perform a design-space exploration of the multi-path relaying effect in RIC Wireless Power Transfer Systems.
Documented prevalence of alcohol misuse among older adult patients at Birmingham Heartlands Hospital is significantly lower than the national prevalence. We aimed to evaluate our alcohol misuse screening protocol for older adults to identify possible shortcomings. Hospital protocol is to screen all adults for alcohol misuse in the accident and emergency (A&E) department using the Fast Alcohol Screening Test (FAST). One hundred consecutive consenting in-patients aged 65–94 admitted via A&E subsequently undertook an additional alcohol screening test (Michigan Alcoholism Screening Test-Geriatric version; MAST-G). Results of the two tests were compared.
FAST screening was completed for 71 patients and none were FAST-positive for alcohol misuse, yet using MAST-G, 18 patients scored positively for alcohol misuse. FAST screening failed to identify 8 patients with a documented history of alcohol misuse.
Older adult alcohol misuse prevalence is significantly underreported using FAST. Screening older adults for alcohol problems requires a different approach to screening the general population.
In November 2013, national public health agencies in England and Scotland identified an increase in laboratory-confirmed Salmonella Mikawasima. The role of proton pump inhibitors (PPIs) as a risk factor for salmonellosis is unclear; we therefore captured information on PPI usage as part of our outbreak investigation. We conducted a case-control study, comparing each case with two controls. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression. Thirty-nine of 61 eligible cases were included in the study. The median age of cases was 45 years; 56% were female. Of these, 33% were admitted to hospital and 31% reported taking PPIs. We identified an association between PPIs and non-typhoidal salmonellosis (aOR 8·8, 95% CI 2·0–38·3). There is increasing evidence supporting the existence of an association between salmonellosis and PPIs; however, biological studies are needed to understand the effect of PPIs in the pathogenesis of Salmonella. We recommend future outbreak studies investigate PPI usage to strengthen evidence on the relevance of PPIs in Salmonella infection. These findings should be used to support the development of guidelines for patients and prescribers on the risk of gastrointestinal infection and PPI usage.
On April 15, 2013, two improvised explosive devices (IEDs) exploded at the Boston Marathon and 264 patients were treated at 26 hospitals in the aftermath. Despite the extent of injuries sustained by victims, there was no subsequent mortality for those treated in hospitals. Leadership decisions and actions in major trauma centers were a critical factor in this response.
The objective of this investigation was to describe and characterize organizational dynamics and leadership themes immediately after the bombings by utilizing a novel structured sequential qualitative approach consisting of a focus group followed by subsequent detailed interviews and combined expert analysis.
Across physician leaders representing 7 hospitals, several leadership and management themes emerged from our analysis: communications and volunteer surges, flexibility, the challenge of technology, and command versus collaboration.
Disasters provide a distinctive context in which to study the robustness and resilience of response systems. Therefore, in the aftermath of a large-scale crisis, every effort should be invested in forming a coalition and collecting critical lessons so they can be shared and incorporated into best practices and preparations. Novel communication strategies, flexible leadership structures, and improved information systems will be necessary to reduce morbidity and mortality during future events. (Disaster Med Public Health Preparedness. 2015;9:489–495)
Biomolecules have been traditionally immobilised onto surfaces using wet chemical techniques for various medical applications. Recent decades have seen plasma methods being used to prepare these surfaces through various forms of surface modification, but the direct exposure of biomolecules to plasma has been avoided due to fears that the molecules would be denatured by the energetic plasma species. Recent results are now demonstrating that direct plasma deposition of biomolecule coatings can be achieved. This creates the possibility to directly modify the surface of implants without any form of surface pre-treatment and this opens up the possibility to alter the healing processes. Materials such as collagen, chitosan, catalase and heparin can be effectively deposited onto surfaces with minimal impact on biological performance and without any chemical binders, linkers or impurities. The performance of these materials has been characterised using both in vitro and in vivo methodologies. In a further step, the results of a preclinical trial are presented which reveal that direct deposition of biomolecules onto open wounds can also be achieved and the impact of this on wound healing is measured in an immunocompromised animal model. A non-thermal plasma device was used to deliver collagen on to chronic wounds and the treatment was shown to promote wound closure in a rabbit wound healing model.
In North America, terrestrial records of biodiversity and climate change that span Marine Oxygen Isotope Stage (MIS) 5 are rare. Where found, they provide insight into how the coupling of the ocean–atmosphere system is manifested in biotic and environmental records and how the biosphere responds to climate change. In 2010–2011, construction at Ziegler Reservoir near Snowmass Village, Colorado (USA) revealed a nearly continuous, lacustrine/wetland sedimentary sequence that preserved evidence of past plant communities between ~140 and 55 ka, including all of MIS 5. At an elevation of 2705 m, the Ziegler Reservoir fossil site also contained thousands of well-preserved bones of late Pleistocene megafauna, including mastodons, mammoths, ground sloths, horses, camels, deer, bison, black bear, coyotes, and bighorn sheep. In addition, the site contained more than 26,000 bones from at least 30 species of small animals including salamanders, otters, muskrats, minks, rabbits, beavers, frogs, lizards, snakes, fish, and birds. The combination of macro- and micro-vertebrates, invertebrates, terrestrial and aquatic plant macrofossils, a detailed pollen record, and a robust, directly dated stratigraphic framework shows that high-elevation ecosystems in the Rocky Mountains of Colorado are climatically sensitive and varied dramatically throughout MIS 5.
In this paper, high temperature (>1400°C) thermal oxidation has been applied, for the first time, to 4H-SiC PiN diodes with thick (110 μm) drift regions, for the purpose of increasing the carrier lifetime in the semiconductor. PiN diodes were fabricated using 4H-SiC material that had undergone thermal oxidation performed at 1400°C, 1500°C and 1600°C, then were electrically characterized. Forward current-voltage (I-V) measurements showed that thermally oxidized PiN diodes exhibited considerably improved electrical characteristics, with devices oxidized at 1500°C having a forward voltage drop (VF) of 4.15 V and a differential on-resistance (Ron,diff) of 8.9 mΩ-cm2 at 100 A/cm2 and 25°C. Compared to typical control sample PiN diode characteristics, this equated to an improvement of 8% and 23% for VF and Ron,diff, respectively. From analysis of the reverse recovery characteristics, the carrier lifetime of the PiN diodes oxidized at 1500°C was found to be 1.05 μs, which was an improvement of around 30% compared to the control sample PiN diodes.
Male dairy calves may be transported from their farm of origin at a young age. This process may involve an extended period off feed and indirect consignment through an intermediate facility, prompting potential welfare concerns. To assess the impact of transport, 59 male Holstein-Friesian dairy calves (5–9 d old) were either (1) held in situ on farm (control); (2) transported for 6 h; (3) transported for 12 h; or (4) transported for 1 h to a holding facility where they were kept for 6 h and then transported for 5 h. All treatments included a 30-h period of feed (milk) withdrawal, and calf responses were measured over time from before their last feed until the completion of the study after the transport and feed withdrawal periods. Apart from increases in serum creatine kinase in calves transported for 12 h, transported calves generally did not differ in blood concentrations of glucose, beta-hydroxybutyrate, lactate, total protein or in packed cell volume, compared with controls (P>0·05). Calf responses to the indirect consignment treatment did not differ from those of other transported calves. Withdrawal of feed for 30 h caused calves to lose 6% of body weight; blood glucose varied from 3·96 mmol/l immediately before daily feeding to 5·46 mmol/l at 3 h post feeding, and then declined to 3·43 mmol/l at 30 h. Calves lay down for 22–32% of the time during transport, and did not show a rebound effect in lying behaviour post arrival in comparison with controls. Best practice transport of 6–12 h duration, including indirect consignment via a holding facility, did not significantly affect calf blood biochemistry and metabolism in comparison with untransported animals. However, extending the time off feed beyond the daily feeding interval resulted in reduced blood glucose concentrations, suggesting that time off feed needs to be carefully managed in young transported dairy calves.
This study aims to explore the possible reasons for the lower levels of diagnosis of chronic fatigue syndrome/myalgic encephalitis (CFS/ME) in the black and minority ethnic (BME) population, and the implications for management.
Population studies suggest CFS/ME is more common in people from BME communities compared with the White British population. However, the diagnosis is made less frequently in BME groups.
Semi-structured qualitative interviews were conducted with 35 key stakeholders in NW England. Interviews were analysed using open explorative thematic coding.
There are barriers at every stage to the diagnosis and management of CFS/ME in people from BME groups. This begins with a lack of awareness of CFS/ME among BME respondents. Religious beliefs and the expectation of roles in the family and community mean that some people in BME groups may choose to manage their symptoms outside primary care using alternative therapies, prayer or spiritual healing. When accessing primary care, all participants recognised the possible influence of language barriers in reducing the likelihood of a diagnosis of CFS/ME. Stereotypical beliefs, including labels such as ‘lazy’ or ‘work shy’ were also believed to act as a barrier to diagnosis. Patients highlighted the importance of an on-going relationship with the general practitioner (GP), but perceived a high turnover of GPs in inner city practices, which undermined the holistic approach necessary to achieve a diagnosis.
Training is required for health professionals to challenge inaccurate assumptions about CFS/ME in BME groups. The focus on the individual in UK primary care may not be appropriate for this group due to the role played by the family and community in how symptoms can be presented and managed. Culturally sensitive, educational resources for patients are also needed to explain symptoms and legitimise consultation.
Multiple birth remains prevalent, with prematurity and subsequent disability being common complications. However, little is known of the experiences of mothers living with the combined circumstances of multiple birth, prematurity, and special needs. This paper reports an exploratory study using the qualitative technique of thematic analysis, to describe and interpret the experiences of 10 mothers of prematurely born multiple birth children with diverse special needs. Mothers were shocked to learn they were carrying multiple fetuses, including those who underwent in vitro fertilization with dual embryo transfer. Most experienced protracted concern over one or more babies’ survival during pregnancy, and prescribed bed rest was frequently associated with increased anxiety and other adverse psychological effects. Some experienced disenfranchised grief, such as those grieving the opportunity to bear a single child. The contrast with experiences of mothers of healthy, term singletons caused considerable distress. Feelings of detachment and unreality were common in the immediate postpartum period, possibly due to transient depersonalization. Having more than one newborn created practical and psychological problems during the neonatal period, particularly when infants were separated due to differences in medical status. The extent to which hospitals accommodated the multiple birth relationship varied and significantly affected mothers’ postnatal experiences. Mothers often felt guilty, particularly regarding inequality of care and attention they were able to provide to each child. This was especially problematic for multiples discordant for special needs status. The presence of one normally developing child complicated adjustment to the other's difficulties, and several experienced chronic sorrow. Serious maternal mental health difficulties were common but not universal. Available formal supports were generally perceived as inadequate, addressing some, but not all, of the mothers’ needs. Further work is needed to advance understanding of the relationships between mothers and their multiples, and to explore the implications of special needs within multiple birth families.