Magnetotransport in p-type Ge quantum well narrow wire arrays

We report magnetotransport measurements of a SiGe heterostructure containing a 20 nm p-Ge quantum well with a mobility of 800 000 cm2 V−1 s−1. By dry etching arrays of wires with widths between 1.0 μm and 3.0 μm, we were able to measure the lateral depletion thickness, built-in potential, and the phase coherence length of the quantum well. Fourier analysis does not show any Rashba related spin-splitting despite clearly defined Shubnikov-de Haas oscillations being observed up to a filling factor of ν = 22. Exchange-enhanced spin-splitting is observed for filling factors below ν = 9. An analysis of boundary scattering effects indicates lateral depletion of the hole gas by 0.5 ± 0.1 μm from the etched germanium surface. The built-in potential is found to be 0.25 ± 0.04 V, presenting an energy barrier for lateral transport greater than the hole confinement energy. A large phase coherence length of 3.5 ± 0.5 μm is obtained in these wires at 1.7 K.This work was supported by the EPSRC funded “Spintronic device physics in Si/Ge heterostructures” EP/J003263/1 and EP/J003638/1 projects and a Platform Grant No. EP/J001074/1.This is the author accepted manuscript. The final version is available from AIP via http://dx.doi.org/10.1063/1.4919053

Serine-like proteolytic enzymes correlated with differential pathogenicity in patients with acute Acanthamoeba keratitis

P>Acute ocular infection due to free-living amoebae of the genus Acanthamoeba is characterized by severe pain, loss of corneal transparency and, eventually, blindness. Proteolytic enzymes secreted by trophozoites of virulent Acanthamoeba strains have an essential role in the mechanisms of pathogenesis, including adhesion, invasion and destruction of the corneal stroma. in this study, we analysed the relationship between the extracellular proteases secreted by clinical isolates of Acanthamoeba and the clinical manifestations and severity of disease that they caused. Clinical isolates were obtained from patients who showed typical symptoms of Acanthamoeba keratitis. Trophozoites were cultivated axenically, and extracellular proteins were collected from cell culture supernatants. Secreted enzymes were partially characterized by gelatin and collagen zymography. Acanthamoeba trophozoites secreted proteases with different molecular masses, proteolysis rates and substrate specificities, mostly serine-like proteases. Different enzymatic patterns of collagenases were observed, varying between single and multiple collagenolytic activities. Low molecular weight serine proteases were secreted by trophozoites associated with worse clinical manifestations. Consequently, proteolytic enzymes of some Acanthamoeba trophozoites could be related to the degree of their virulence and clinical manifestations of disease in the human cornea.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Federal University of São Paulo (FADA-UNIFESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo, Dept Ophthalmol, Paulista Sch Med, Cornea & External Dis Serv, BR-04023062 São Paulo, BrazilUniv São Paulo, Biochem & Biophys Lab, Butantan Inst, São Paulo, BrazilUniv São Paulo, Inst Biomed Sci, Dept Parasitol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Ophthalmol, Paulista Sch Med, Cornea & External Dis Serv, BR-04023062 São Paulo, BrazilFAPESP: 08/53969-0FAPESP: 05/59739-9Web of Scienc

Controlling magnetic order and quantum disorder in molecule-based magnets.

We investigate the structural and magnetic properties of two molecule-based magnets synthesized from the same starting components. Their different structural motifs promote contrasting exchange pathways and consequently lead to markedly different magnetic ground states. Through examination of their structural and magnetic properties we show that [Cu(pyz)(H 2 O)(gly) 2 ](ClO 4 ) 2 may be considered a quasi-one-dimensional quantum Heisenberg antiferromagnet whereas the related compound [Cu(pyz)(gly)](ClO 4 ) , which is formed from dimers of antiferromagnetically interacting Cu 2+ spins, remains disordered down to at least 0.03 K in zero field but shows a field-temperature phase diagram reminiscent of that seen in materials showing a Bose-Einstein condensation of magnons

Controlling magnetic order and quantum disorder in molecule-based magnets

We investigate the structural and magnetic properties of two molecule-based magnets synthesized from the same starting components. Their different structural motifs promote contrasting exchange pathways and consequently lead to markedly different magnetic ground states. Through examination of their structural and magnetic properties we show that [Cu(pyz)(H2O)(gly)2](ClO4)2 may be considered a quasi-one-dimensional quantum Heisenberg antiferromagnet whereas the related compound [Cu(pyz)(gly)](ClO4), which is formed from dimers of antiferromagnetically interacting Cu2+ spins, remains disordered down to at least 0.03 K in zero field but shows a field-temperature phase diagram reminiscent of that seen in materials showing a Bose-Einstein condensation of magnons

The implausibility of ‘usual care’ in an open system: sedation and weaning practices in Paediatric Intensive Care Units (PICUs) in the United Kingdom (UK)

Background: The power of the randomised controlled trial depends upon its capacity to operate in a closed system whereby the intervention is the only causal force acting upon the experimental group and absent in the control group, permitting a valid assessment of intervention efficacy. Conversely, clinical arenas are open systems where factors relating to context, resources, interpretation and actions of individuals will affect implementation and effectiveness of interventions. Consequently, the comparator (usual care) can be difficult to define and variable in multi-centre trials. Hence outcomes cannot be understood without considering usual care and factors that may affect implementation and impact on the intervention. Methods: Using a fieldwork approach, we describe PICU context, ‘usual’ practice in sedation and weaning from mechanical ventilation, and factors affecting implementation prior to designing a trial involving a sedation and ventilation weaning intervention. We collected data from 23 UK PICUs between June and November 2014 using observation, individual and multi-disciplinary group interviews with staff. Results: Pain and sedation practices were broadly similar in terms of drug usage and assessment tools. Sedation protocols linking assessment to appropriate titration of sedatives and sedation holds were rarely used (9 % and 4 % of PICUs respectively). Ventilator weaning was primarily a medical-led process with 39 % of PICUs engaging senior nurses in the process: weaning protocols were rarely used (9 % of PICUs). Weaning methods were variably based on clinician preference. No formal criteria or use of spontaneous breathing trials were used to test weaning readiness. Seventeen PICUs (74 %) had prior engagement in multi-centre trials, but limited research nurse availability. Barriers to previous trial implementation were intervention complexity, lack of belief in the evidence and inadequate training. Facilitating factors were senior staff buy-in and dedicated research nurse provision. Conclusions: We examined and identified contextual and organisational factors that may impact on the implementation of our intervention. We found usual practice relating to sedation, analgesia and ventilator weaning broadly similar, yet distinctively different from our proposed intervention, providing assurance in our ability to evaluate intervention effects. The data will enable us to develop an implementation plan; considering these factors we can more fully understand their impact on study outcomes

Health risk assessment and health risk management with special reference to sodium monofluoroacetate (1080) for Possum control in New Zealand

The principal use of sodium monofluoroacetate (1080) in New Zealand is to control brushtail possums (Trichosurus vulpecula). Aerial application of baits containing 1080 is the most common method used for large-scale control of possums. The use of 1080 attracts a great deal of controversy, in particular the effects on the environmental, non-target species, and the potential chronic effects in humans associated with environmental exposures. Although the nature of the acute toxicity of 1080 has been known for more than fifty years, little is known of its effects on humans, in particular its chronic effects to environmental exposures. A benchmark dose (BMD) as an alternative to a no-observed-adverse-effect-level (NOAEL) approach was investigated as a means to improve current health risk assessment values of 1080. Both approaches were investigated for three critical toxicological end points, namely cardiomyopathy, testicular toxicity and teratogenic effects identified from the few available critical studies. The calculated BMDs and lower-bound confidence limits (BMDLs) for the three end points were estimated using the Weibull, probit and quanntal linear models. A benchmark response (BMR) of 10% (extra risk) was chosen and the Akaike's information criterion (AIC) was used in selecting the appropriate model. The BMDL estimates derived were generally slightly higher but comparable to the corresponding NOAEL for those same endpoints. The computed BMD10 and BMDL10 for cardiomyopathy and testicular effects were 0.21 mg kg^(-1) bw^(-1) and 0.10 mg kg^(-1) bw^(-1) respectively. Tolerable Daily Intakes (TDIs) were derived using the NOAEL approach and the BMD methodology and applying an uncertainty factor of 3000. The resulting TDI using the BMDL were generally consistently slightly higher than those derived using the NOAEL approach. Based on the best fit of modelled dose-response data, a TDI of 0.03 μg kg^(-1) bw^(-1) day^(-1) is proposed for human health risk assessment. Two sets of Provisional Maximum Acceptable Values (PMA V) were derived using the highest concentration of 4.0 μg L^(-1)1080 found in water (N=1450), and using the maximum allowable concentration of2.0 μg L^(-1) of 1080 in water for adults (0.58 μg L^(-1) and 0.94 μg L^(-1) , respectively) and children (0.23 μg L^(-1) and 0.4 μg L^(-1), respectively). Parameters used in the derivation of PMA Vs were average weight, average quantity of water consumed, and proportion of total intake allocated to drinking water. The derived adult PMA V of 0.60 μg L^(-1)is proposed in revising the PMA V for 1080 in the Drinking Water Standards New Zealand. This value is 6-fold lower than the current PMA V of 3.5 μg L^(-1). Additional toxicology studies are recommended to meet the definition of a "complete database" and therefore estimating a more defensible TDI, and consequently a PMAV for 1080. Risk management approaches are consistent with the Ministry of Health's current precautionary approach. A PMA V of 0.60 μg L^(-1) in drinking water is recommended to consider it suitable for human consumption and that continuous monitoring be carried if the level of 1080 exceeds 50% of the proposed PMAV as a requirement for Priority 2 determinands in the Drinking Water Standards. Precautionary approach appears to be warranted and this was supported by information provided by the Public Health Units (PHU) where 1080 was permitted to be dropped onto drinking water catchments. The PHU s exercised precautionary measures by imposing appropriate conditions to suit local circumstances. As 1080 may likely remain an essential tool to contain tuberculosis spread by possums and to reduce possum damage to forests and crops until better methods of control are developed, a number of recommendations were proposed to protect public health

Cultural humility: A concept analysis

Session presented on Saturday, July 25, 2015: Diversity is being increasingly recognized as an area of emphasis in health care. The term cultural humility is used frequently but society\u27s understanding of the term is unclear. The aim of this paper was to provide a concept analysis and a current definition for the term cultural humility. To capture society\u27s definition of the term, seven databases representing different disciplines were explored. Abstracts were read for relevance and sixty two articles from were included in the review. Rodgers and Knafl\u27s (2000) method of concept analysis was used to guide the process. Cultural humility was used in a variety of contexts from individuals having ethnic and racial differences, to differences in sexual preference, social status, interprofessional roles, to healthcare provider/patient relationships. The attributes were openness, self-awareness, egoless, supportive interactions, and self-reflection and critique. The antecedents were diversity and power imbalance. The consequences were mutual empowerment, partnerships, respect, optimal care, and lifelong learning. Cultural humility was described as a lifelong process. With a firm understanding of the term, individuals and communities will be better equipped to understand and accomplish an inclusive environment with mutual benefit and optimal care

Distribution and genetic variation of hymenolepidid cestodes in murid rodents on the Canary Islands (Spain)

<p>Abstract</p> <p>Background</p> <p>In the Canary Islands there are no previous data about tapeworms (Cestoda) of rodents. In order to identify the hymenolepidid species present in these hosts, a survey of 1,017 murine (349 <it>Rattus rattus</it>, 13 <it>Rattus norvegicus </it>and 655 <it>Mus musculus domesticus</it>) was carried out in the whole Archipelago. Molecular studies based on nuclear <it>ITS1 </it>and mitochondrial <it>COI </it>loci were performed to confirm the identifications and to analyse the levels of genetic variation and differentiation.</p> <p>Results</p> <p>Three species of hymenolepidids were identified: <it>Hymenolepis diminuta</it>, <it>Rodentolepis microstoma </it>and <it>Rodentolepis fraterna</it>. <it>Hymenolepis diminuta </it>(in rats) and <it>R. microstoma </it>(in mice) showed a widespread distribution in the Archipelago, and <it>R. fraterna </it>was the least spread species, appearing only on five of the islands. The hymenolepidids found on Fuerteventura, Lanzarote and La Graciosa were restricted to one area. The <it>COI </it>network of <it>H. diminuta </it>showed that the haplotypes from Lanzarote and Fuerteventura are the most distant with respect to the other islands, but clearly related among them.</p> <p>Conclusions</p> <p>Founder effects and biotic and abiotic factors could have played important role in the presence/absence of the hymenolepidid species in determined locations. The haplotypes from the eastern islands (Fuerteventura and Lanzarote) seem to have shared an ancestral haplotype very distant from the most frequent one that was found in the rest of the islands. Two colonization events or a single event with subsequent isolation and reduced gene flow between western-central and eastern islands, have taken place in the Archipelago. The three tapeworms detected are zoonotic species, and their presence among rodents from this Archipelago suggests a potential health risk to human via environmental contamination in high risk areas. However, the relatively low prevalence of infestations detected and the focal distribution of some of these species on certain islands reduce the general transmission risk to human.</p

CPAf Updates Vol. 15 Issue No. 6

In this Issue: CISC forum tackles post-2014 CARP scenario, 1 USAID BAWP gears for final year, 2 Social Sciences in UPLB revisited, 3 CPAf participates in ICRAF workshop on property rights Baconguis, Gasmen present studies on organic agriculture,5 Pintor awarded best paper, 6 Serrano awarded on T’boli paper, 6 Salvacion, et al. research published in Elsevier journal, 8https://www.ukdr.uplb.edu.ph/cpaf-updates/1050/thumbnail.jp

Local magnetism and spin dynamics of the frustrated honeycomb rhodate Li2RhO3

We reportmagnetization, heat capacity, 7Li nuclear magnetic resonance (NMR), and muon-spin rotation (μSR) measurements on the honeycomb 4d5 spin liquid candidate Li2RhO3. The magnetization in small magnetic fields provides evidence of the partial spin-freezing of a small fraction of Rh4+ moments at 6 K, whereas the Curie-Weiss behavior above 100 K suggests a pseudo-spin-1/2 paramagnet with a moment of about 2.2μB. The magnetic specific heat (Cm) exhibits no field dependence and demonstrates the absence of long-range magnetic order down to 0.35 K. Cm/T passes through a broad maximum at about 10 K and Cm ∝ T 2 at low temperatures. Measurements of the spin-lattice relaxation rate (1/T1) reveal a gapless slowing-down of spin fluctuations upon cooling with 1/T1 ∼ T 2.2. The results from NMR and μSR are consistent with a scenario in which a minority of Rh4+ moments are in a short-range correlated frozen state and coexist with a majority of moments in a liquid-like state that continue to fluctuate at low temperatures