Functionally graded Ni-Ti microstructures synthesised in process by direct laser metal deposition

The fabrication of biomedical devices using Ni-Ti compositions is limited to conventional techniques and the use of near equiatomic pre-alloyed Ni and Ti powders. In this study, functionally graded walls and cylinder built by concurrent feeding of Ni powder and commercially pure (CP) Ti wire using direct laser metal deposition technique are presented. The built structures consist of CP Ti wire-deposited layers and Ni-Ti layers of varying Ni composition. The microstructures of the built Ni-Ti structures including phase identification, phase compositions and area fractions of the phases present at various processing parameters were determined using a combination of scanning electron microscopy/ energy dispersive X-ray spectroscopy, X-ray diffractometry and image processing software. Vickers microhardness test was conducted on the deposited structures. It was found that the Ni-Ti layers comprise of NiTi and NiTi2 phases. The area fraction of the NiTi phase increases, whereas NiTi2 decreases with increasing the Ni powder feed rate. Ni-Ti layers with higher area fractions of NiTi2 phase are found to be harder with a maximum of 513 HV0.3 found in this study. The micro-hardness of Ni-Ti layers is, by at least a factor of 1.5, higher than the CP Ti wire laser-deposited layers

Medico-religious collaboration: a model for mental health care in a resource poor country

Background: Reducing the treatment gap for the treatment of people with psychiatric disorders (also known as the ‘mental health gap’) is of increasing importance worldwide. In Low and Middle Income Countries (LMICs) human and material resources for orthodox (‘western’) mental health care are severely inadequate. As such, alternative mental health practices tend to thrive. Such alternative systems of care could be formally linked with western services to achieve a more integrated pattern of care in order to improve access for all users of mental health services in these communities, while ensuring a reduction in harm and promoting the human rights of people with mental health problems.Aim: To describe a medico-religious mental health care collaborative model in a rural community in Nigeria, which may be suitable for scaling up mental health care in LMICs as a whole.Methods: This is a descriptive report of a psychiatric service in collaboration with a Christian religious settlement, based in Ogun State, Western Nigeria. Questionnaires, focus group discussions and direct observation were employed. Client records from the religious center and from the visiting psychiatric team were also examined, and all the data from all sources were synthesized.Results: Interactions between the medical and religious mental health care providers improved consistently over the study period. Acceptance of medical services and understanding of the need for collaboration increased. Increased utilization by people with mental illness from the nearby settlement was observed. In the course of collaboration, the occurrence of harmful practices(though still much in practice), reduced considerably as evidenced by stoppage of prolonged sleep and food deprivation (in form of night vigils and fasting) and flagellation, while physical restrictions with chains, especially for newly admitted sufferers still continued unabated despite the discouragement of such practice by medical practitioners.Conclusions: A structured collaborative arrangement between medical and religious health care practitioners offers a great possibility towards the scaling up of mental health care in a resource poor setting such as Nigeria. In addition, it offers potential benefits to services users, such as: improved access to proven reliable medical care, better continuity of care, and reduction in harmful traditional practices usually used to treat these groups of people. Challenges of fundamental human rights abuse and funding are important areas for local mental health policies to address in such settings. In addition, institutional support is still inadequate and there is need for program sustainability.Keywords: Collaboration, Medico-religion, Mental health, Resource poor, LMI

Soluble abrasives for waterjet machining

© 2014 Taylor & Francis Group, LLC. The addition of hard abrasives to the jet in waterjet machining can improve machining rate, however, embedding of particles in machined surfaces is a limitation, which results in reduced fatigue life, and limits the application of well adhered subsequent coatings to the surface. In this study, softer soluble abrasives were investigated as a potential solution. Soluble abrasives yielded a higher material removal rate compared to plain waterjet, although were not as effective as traditional hard abrasives. Soluble abrasives reduced grit embedment on all four workpiece materials. A post-machining surface cleaning operation demonstrated that any remaining soluble abrasive could be removed

Transinfection of buffalo flies (Haematobia irritans exigua) with Wolbachia and effect on host biology

Buffalo flies (Haematobia irritans exigua) (BF) and closely related horn flies (Haematobia irritans irritans) (HF) are invasive haematophagous parasites with significant economic and welfare impacts on cattle production. Wolbachia are intracellular bacteria found widely in insects and currently of much interest for use in novel strategies for the area wide control of insect pests and insect-vectored diseases. In this paper, we report the transinfection of BF towards the development of area-wide controls

Microbial use of low molecular weight DOM in filtered and unfiltered freshwater:Role of ultra-small microorganisms and implications for water quality monitoring

Dissolved organic matter (DOM) plays a central role in regulating productivity and nutrient cycling in freshwaters. It is therefore vital that we can representatively sample and preserve DOM in freshwaters for subsequent analysis. Here we investigated the effect of filtration, temperature (5 and 25 °C) and acidification (HCl) on the persistence of low molecular weight (MW) dissolved organic carbon (DOC), nitrogen (DON) and orthophosphate in oligotrophic and eutrophic freshwater environments. Our results showed the rapid loss of isotopically-labelled glucose and amino acids from both filtered (0.22 and 0.45 μm) and unfiltered waters. We ascribe this substrate depletion in filtered samples to the activity of ultra-small (< 0.45 μm) microorganisms (bacteria and archaea) present in the water. As expected, the rate of C, N and P loss was much greater at higher temperatures and was repressed by the addition of HCl. Based on our results and an evaluation of the protocols used in recently published studies, we conclude that current techniques used to sample water for low MW DOM characterisation are frequently inadequate and lack proper validation. In contrast to the high degree of analytical precision and rigorous statistical analysis of most studies, we argue that insufficient consideration is still given to the presence of ultra-small microorganisms and potential changes that can occur in the low MW fraction of DOM prior to analysis

The 2018 Geothermal Reservoir Stimulation in Espoo/Helsinki, Southern Finland: Seismic Network Anatomy and Data Features

A seismic network was installed in Helsinki, Finland to monitor the response to an similar to 6-kilometer-deep geothermal stimulation experiment in 2018. We present initial results of multiple induced earthquake seismogram and ambient wavefield analyses. The used data are from parts of the borehole network deployed by the operating St1 Deep Heat Company, from surface broadband sensors and 100 geophones installed by the Institute of Seismology, University of Helsinki, and from Finnish National Seismic Network stations. Records collected in the urban environment contain many signals associated with anthropogenic activity. This results in time- and frequency-dependent variations of the signal-to-noise ratio of earthquake records from a 260-meter-deep borehole sensor compared to the combined signals of 24 collocated surface array sensors. Manual relocations of similar to 500 events indicate three distinct zones of induced earthquake activity that are consistent with the three clusters of seismicity identified by the company. The fault-plane solutions of 14 selected ML 0.6-1.8 events indicate a dominant reverse-faulting style, and the associated SH radiation patterns appear to control the first-order features of the macroseismic report distribution. Beamforming of earthquake data from six arrays suggests heterogeneous medium properties, in particular between the injection site and two arrays to the west and southwest. Ambient-noise cross-correlation functions reconstruct regional surface-wave propagation and path-dependent body-wave propagation. A 1D inversion of the weakly dispersive surface waves reveals average shear-wave velocities around 3.3 km/s below 20 m depth. Consistent features observed in relative velocity change time series and in temporal variations of a proxy for wavefield partitioning likely reflect the medium response to the stimulation. The resolution properties of the obtained data can inform future monitoring strategies and network designs around natural laboratories.Peer reviewe

Fire distinguishers: Refined interpretations of polycyclic aromatic hydrocarbons for paleo-applications

Polycyclic aromatic hydrocarbons (PAHs), produced via incomplete combustion of organics, convey signatures of vegetation burned in the geologic past. New and published burn experiments reveal how the quantity, distributions, and isotopic abundances of fire-derived PAHs were influenced by fuel types, burn conditions, and also phase. PAH concentrations were higher in burn residues from moderate burn temperatures (400–500 °C), and significantly lower in residues from cooler (600 °C) conditions, especially when oxygen was limited. PAH forms tended to be smaller in smoke samples and larger in residues, consistent with molecular physical and chemical properties. Plant functional types were distinguished by relative amounts of retene and dimethyl phenanthrene isomers. Isotopically distinct photosynthetic pathways of the burned material were reflected in the δ13C values of PAHs, which faithfully captured biomass signatures as well as the ∼12‰ offset between C3 and C4 plant types. PAH size, alkylation, and isotope characteristics can differentiate combusted plant types and distinguish between air-borne and sedimentary transport mechanisms. New proxy approaches using PAH amounts, distributions, and isotope signatures can aid and refine interpretations of paleofire ecology in the geologic record

Survival and cellular heterogeneity of epithelium in cultured mouse and rat precision-cut intestinal slices

Precision-cut intestinal slices (PCIS) are used to study intestinal (patho)physiology, drug efficacy, toxicity, transport and metabolism ex vivo. One of the factors that limit the use of PCIS is a relatively short life-span. Moreover, culture-induced changes in cellular composition of PCIS remain largely uncharacterized. In this study, we demonstrated the epithelial cell heterogeneity in mouse and rat PCIS and its alterations during culture. In addition, we evaluated whether the presence of niche growth factors impacts the survival of PCIS epithelial cells. We showed that freshly prepared PCIS retained the main epithelial cell types, namely absorptive enterocytes, goblet cells, enteroendocrine cells, stem cells, transit-amplifying cells and Paneth cells. Once placed in culture, PCIS displayed progressive epithelial damage, and loss of these epithelial cell types. Cells comprising the intestinal stem cell niche were especially sensitive to the damage, and the addition of niche growth factors beneficially affected the survival of stem cells and transit-amplifying cells in PCIS during culture. In conclusion, this study provides new insights into the dynamic changes in cellular composition of epithelium in cultured PCIS, paving the way to future toxicological and pharmacological studies in an informed and reliable ex vivo setting

Vortex dynamics for two-dimensional XY models

Two-dimensional XY models with resistively shunted junction (RSJ) dynamics and time dependent Ginzburg-Landau (TDGL) dynamics are simulated and it is verified that the vortex response is well described by the Minnhagen phenomenology for both types of dynamics. Evidence is presented supporting that the dynamical critical exponent $z$ in the low-temperature phase is given by the scaling prediction (expressed in terms of the Coulomb gas temperature $T^{CG}$ and the vortex renormalization given by the dielectric constant $\tilde\epsilon$) $z=1/\tilde{\epsilon}T^{CG}-2\geq 2$ both for RSJ and TDGL and that the nonlinear IV exponent a is given by a=z+1 in the low-temperature phase. The results are discussed and compared with the results of other recent papers and the importance of the boundary conditions is emphasized.Comment: 21 pages including 15 figures, final versio

Hall-conductivity sign change and fluctuations in amorphous Nbx_{x}Ge1−x_{1-x} films

The sign change in the Hall conductivity has been studied in thin amorphous Nb$_{1-x}$Ge$_x (x\approx$0.3) films. By changing the film thickness it is shown that the field at which the sign reversal occurs shifts to lower values (from above to below the mean-field transition field $H_{c2}$) with increasing film thickness. This effect can be understood in terms of a competition between a positive normal and a negative fluctuation contribution to the Hall conductivity.Comment: 5 pages, 4 figures, to appear in Phys. Rev.