Precision machining of steel decahedrons

Production of highly accurate decahedron prisms from hardened stainless steel is discussed. Prism is used to check angular alignment of mounting pads of strapdown inertial guidance system. Accuracies obtainable using recommended process and details of operation are described. Photographic illustration of production device is included

Modern behaviour in ancient South Africans: evidence for the heat treatment of stones in the Middle Stone Age

To what extent was fire used as an engineering tool by early modern humans? Kyle Brown and co-authors marshal an impressive array of evidence to show that by 72 000 years ago, and perhaps as far back as 164 000 years ago, prehistoric people prepared the stone from which they planned to make artefacts by intentionally heat-treating it to improve its flaking qualities. This practice is well known from later sites but the increased time depth reported here is remarkable, and contributes to a growing body of evidence that Middle Stone Age people in South Africa were capable of far more sophisticated behaviour than previously realised

Highly conductive Sb-doped layers in strained Si

The ability to create stable, highly conductive ultrashallow doped regions is a key requirement for future silicon-based devices. It is shown that biaxial tensile strain reduces the sheet resistance of highly doped n-type layers created by Sb or As implantation. The improvement is stronger with Sb, leading to a reversal in the relative doping efficiency of these n-type impurities. For Sb, the primary effect is a strong enhancement of activation as a function of tensile strain. At low processing temperatures, 0.7% strain more than doubles Sb activation, while enabling the formation of stable, ~10-nm-deep junctions. This makes Sb an interesting alternative to As for ultrashallow junctions in strain-engineered complementary metal-oxide-semiconductor device

A simple modification of the A. nidulans transformation protocol increases the transformation frequency

After transformation of Aspergillus nidulans with plasmid DNA the transformants are usually incubated at 37C until transformants appear. We have found that pre-incubation of the transformation plates at room temperature for 24h leads to increased transformation frequencies

Variability in H9N2 haemagglutinin receptor-binding preference and the pH of fusion

H9N2 avian influenza viruses are primarily a disease of poultry; however, they occasionally infect humans and are considered a potential pandemic threat. Little work has been performed to assess the intrinsic biochemical properties related to zoonotic potential of H9N2 viruses. The objective of this study, therefore, was to investigate H9N2 haemagglutinins (HAs) using two well-known correlates for human adaption: receptor-binding avidity and pH of fusion. Receptor binding was characterized using bio-layer interferometry to measure virus binding to human and avian-like receptor analogues and the pH of fusion was assayed by syncytium formation in virus-infected cells at different pHs. We characterized contemporary H9N2 viruses of the zoonotic G1 lineage, as well as representative viruses of the zoonotic BJ94 lineage. We found that most contemporary H9N2 viruses show a preference for sulphated avian-like receptor analogues. However, the ‘Eastern’ G1 H9N2 viruses displayed a consistent preference in binding to a human-like receptor analogue. We demonstrate that the presence of leucine at position 226 of the HA receptor-binding site correlated poorly with the ability to bind a human-like sialic acid receptor. H9N2 HAs also display variability in their pH of fusion, ranging between pH 5.4 and 5.85 which is similar to that of the first wave of human H1N1pdm09 viruses but lower than the pH of fusion seen in zoonotic H5N1 and H7N9 viruses. Our results suggest possible molecular mechanisms that may underlie the relatively high prevalence of human zoonotic infection by particular H9N2 virus lineages

An effective electrical isolation scheme by iron implantation at different substrate temperatures

High-energy implantation of iron in n-type doped InP epilayers at different substrate temperatures: 77K, room temperature (RT), 100degreesC and 200degreesC was investigated to study the electrical isolation of n-type InP. Iron isolation implants were performed at 1MeV with a fluence of 5 x 10(14) /cm(2). This isolation scheme was chosen to place most of the iron atoms well inside the n-type doped layer. The sheet resistivity (R,), sheet carrier concentration (n(S)) and sheet mobility (p) were measured as a function of substrate temperature and post-implantation annealing temperature (100 - 800degreesC). Samples implanted at 77K, RT and 100degreesC show more or less the same trend of postimplant annealing characteristics. A maximum sheet resistivity of similar to1 x 10(7) Omega/rectangle was achieved for samples implanted at 77K, RT and 100degreesC after annealing at 400degreesC. A lower resistivity of similar to1 x 10(6) Omega/rectangle was obtained for a 200degreesC implant after annealing at 4000C. Lower damage accumulation due to enhanced dynamic annealing is observed for the highest implantation temperature. For 200degreesC substrate temperature, annealing above 4000C resulted in a gradual decrease in sheet resistivity to a value close to that of the starting material. But this is not the case for the lower substrate temperatures. The sheet resistivity was increased again for 77K, RT and 100()C implant after annealing at 600degreesC. We infer that for 77K, RT and 100degreesC implantation temperatures, the electrical isolation is due to a product of both damage related centers and defects related to the presence of Fe whereas for 200degreesC substrate temperature, we infer that only damage induced compensation removes the carriers. These results show the importance of iron implants as a device isolation scheme.</p

Ruby-throated Hummingbird, Archilochus colubris, Entanglements in Burdock, Arctium spp., at Delta Marsh, Manitoba

Exotic burdock (Arctium spp.) pose a risk of mortality for small native birds, such as the Ruby-throated Hummingbird (Archilochus colubris), which may become entangled in its burrs. At Delta Marsh, Manitoba, we found 11 hummingbirds and five individuals of four species of songbirds entangled on burdock in the dune-ridge forest over a 20-year period. Entangled birds were mostly migrants. Most hummingbirds caught were juvenile males, whereas the few songbirds were mostly adult males. We suspect that hummingbird entanglements resulted from an attraction to the purple flowers of burdock, but aggressive interactions with conspecifics and other factors may have been involved. Birds may be at a higher risk of entanglement at important migratory stopover sites, such as Delta Marsh, where both burdock and large numbers of birds are concentrated in a small area

Ultrastructural Study of Yam Tuber as Related to Postharvest Hardness

Usually, parenchyma cell walls of monocotyledons do not develop secondary walls; however a few days after harvesting, the yam tuber of Dioscorea dumetorum starts to harden. Two or three weeks Iater, hardness is so pronounced that the tubers cannot be eaten, even after a long cooking time. Cytochemical studies using autofluorescence or some fluorescent dyes, such as phloroglucinol hydrochloride showed that the thin, and flexible cell walls of parenchyma tubers very quickly became fully lignified after harvesting. Ultrastructura 1 stud ies of the hardened ce 11 wa 11 s showed very thick secondary wa 11 s and very deep pit apertures. These secondary walls reacted strong ly with li gn in reactants such as potassium permanganate. The use of a radioactive (l \u27• C) ce llulose precursor, uri dine- 5\u27-d ipho sphateglucose, confirmed the formation of such secondary walls. The lignification started from the corners of the cells around intercellular spaces and proceeded along the walls

Pulsed Laser Cutting of Magnesium-Calcium for Biodegradable Stents

There is growing interests in the use of biodegradable magnesium implants for cardiovascular and pulmonary applications such as stents. Magnesium is a metal that has the ability to gradually dissolve and absorb into the human body after implantation. There is very little work discussing the relationship between process parameters and cut quality of magnesium stents by laser cutting. The objective of this research is to determine the effect of laser cutting conditions including peak laser power and cutting speed of a millisecond range pulsed laser on kerf geometry, surface topography, surface roughness, and microstructure. An assessment on the experimental work discussing laser cutting of magnesium alloys is also presented

The patient-provider relationship and antenatal care uptake at two referral hospitals in Malawi: A qualitative study

Background In post-stroke patients, impairment of quality of life (QOL) has been associated with functional impairment, age, anxiety, depression, and fatigue. Good social support, higher education, and better socioeconomic status are associated with better QOL among stroke survivors. In Africa, studies from Nigeria and Tanzania have reported on post-stroke QOL.Background Approximately 90% of Malawian women attend antenatal care at least once during their pregnancies; however, most mothers first present during months five and six and do not adhere to the World Health Organization’s recommended four visits. The objective of this study was to explore the role the patient-provider relationship has on antenatal care uptake.Methods A qualitative study, consisting of interviews with 20 urban pregnant mothers and eight health workers, was conducted from September to December 2014. Two large tertiary care hospitals in the Central and Southern regions of Malawi were selected as study sites.Results Several factors influenced antenatal care attendance. Significant barriers reported included the patient-provider relationship, clinic wait times, family and friend support, distance from home to the clinic, transportation, cost, and number of visits. The patient-provider relationship appears to have a large impact on antenatal clinic participation. Mothers indicated that health workers often mistreat or demean them during visits. Additionally, health workers revealed that, due to staff shortages, patients often do notreceive the care they deserve.Conclusions The results of this study suggest that, in addition to other factors, healthcare provider attitudes influence antenatal clinic attendance. Improving the patient-provider relationship may increase antenatal clinic attendance and decrease pregnancy complications during pregnancy. Professional development opportunities and quality improvement programmes are would help improve patient care and health outcomes while the continued staff shortages in the country are addressed