Urea production and turnover following the addition of AMP, CMP, RNA and a protein mixture to a marine sediment

The potential of adenosine 5′-monophosphate (AMP), cytidine 5′-monophosphate (CMP), 16S ribosomal RNA, and a protein (bovine serum albumin) to serve as substrates for bacterial urea production was evaluated in a defaunated, anoxic marine sediment. AMP, CMP and RNA stimulated urea production and urea turnover, but CMP to a lesser degree than AMP and RNA. The increase in urea production and turnover rates took place immediately after AMP, CMP, and RNA were added to the sediment. The rapid response in urea production and turnover rates suggests that the necessary uptake mechanisms and enzymes to utilize the substrates were present constitutively. Addition of the protein mixture did not result in any measurable changes in the urea pool size, urea turnover rate, or urea production rate during the 165 h of incubation. However, an increased and continuous net NH4+ production in the protein-amended sediment relative to the control sediment indicated that the added protein mixture was accessible for bacterial degradation. The results showed that purines and pyrimidines were substrates for the bacterial urea production in the marine sediment, whereas protein was not important for urea production

Rabies elimination research: juxtaposing optimism, pragmatism and realism

More than 100 years of research has now been conducted into the prevention, control and elimination of rabies with safe and highly efficacious vaccines developed for use in human and animal populations. Domestic dogs are a major reservoir for rabies, and although considerable advances have been made towards the elimination and control of canine rabies in many parts of the world, the disease continues to kill tens of thousands of people every year in Africa and Asia. Policy efforts are now being directed towards a global target of zero human deaths from dog-mediated rabies by 2030 and the global elimination of canine rabies. Here we demonstrate how research provides a cause for optimism as to the feasibility of these goals through strategies based around mass dog vaccination. We summarize some of the pragmatic insights generated from rabies epidemiology and dog ecology research that can improve the design of dog vaccination strategies in low- and middle-income countries and which should encourage implementation without further delay. We also highlight the need for realism in reaching the feasible, although technically more difficult and longer-term goal of global elimination of canine rabies. Finally, we discuss how research on rabies has broader relevance to the control and elimination of a suite of diseases of current concern to human and animal health, providing an exemplar of the value of a ‘One Health’ approach

Proximate, Vitamins and Mineral Composition of Vitex doniana (black plum) Fruit Pulp

Samples of Vitex doniana fruit (black plum) were collected from Vunchi village in Bida metropolis. The dried endocarp was washed, ground into powder and analysed for the proximate, vitamins and mineral compositions. The values (%DW) of moisture, ash, crude protein, crude fibre, crude fat and carbohydrate available were 16.66, 11.50, 8.24, 0.58, 34.62 and 28.40, respectively. Levels of Vitamin A, B1, B2, B6 and C were 0.27, 18.33, 4.80, 20.45 and 35.58 (mg/100g DW) respectively. Mineral (mg/100g DW) were: potassium (16.5), sodium (10.40), calcium (30.27), iron (5.20), Copper (2.70), magnesium (20.10) and phosphorus (16.50). The result indicates that Vitex doniana fruit pulp could be promoted as: carbohydrate and lipid supplements for cereal-based diets in rural communities, another cheaper source of raw material for juice production, fortified into feed of ruminants, while its moderate calcium value could be used for the management of oesteomalacia

Emergent quantum confinement at topological insulator surfaces

Bismuth-chalchogenides are model examples of three-dimensional topological insulators. Their ideal bulk-truncated surface hosts a single spin-helical surface state, which is the simplest possible surface electronic structure allowed by their non-trivial $\mathbb{Z}_2$ topology. They are therefore widely regarded ideal templates to realize the predicted exotic phenomena and applications of this topological surface state. However, real surfaces of such compounds, even if kept in ultra-high vacuum, rapidly develop a much more complex electronic structure whose origin and properties have proved controversial. Here, we demonstrate that a conceptually simple model, implementing a semiconductor-like band bending in a parameter-free tight-binding supercell calculation, can quantitatively explain the entire measured hierarchy of electronic states. In combination with circular dichroism in angle-resolved photoemission (ARPES) experiments, we further uncover a rich three-dimensional spin texture of this surface electronic system, resulting from the non-trivial topology of the bulk band structure. Moreover, our study reveals how the full surface-bulk connectivity in topological insulators is modified by quantum confinement.Comment: 9 pages, including supplementary information, 4+4 figures. A high resolution version is available at http://www.st-andrews.ac.uk/~pdk6/pub_files/TI_quant_conf_high_res.pd

Care seeking for under-five children and vaccine perceptions during the first two waves of the COVID-19 pandemic in Lagos State, Nigeria: a qualitative exploratory study

Objective: To explore healthcare seeking practices for children and the context-specific direct and indirect effects of public health interventions during the first two waves of COVID-19 in Lagos State, Nigeria. We also explored decision-making around vaccine acceptance at the start of COVID-19 vaccine roll-out in Nigeria. Design, setting and participants: A qualitative explorative study involving 19 semistructured interviews with healthcare providers from public and private primary health facilities and 32 interviews with caregivers of under-five children in Lagos from December 2020 to March 2021. Participants were purposively selected from healthcare facilities to include community health workers, nurses and doctors, and interviews were conducted in quiet locations at facilities. A data-driven reflexive thematic analysis according to Braun and Clark was conducted. Findings: Two themes were developed: appropriating COVID-19 in belief systems, and ambiguity about COVID-19 preventive measures. The interpretation of COVID-19 ranged from fearful to considering it as a ‘scam’ or ‘falsification from the government’. Underlying distrust in government fuelled COVID-19 misperceptions. Care seeking for children under five was affected, as facilities were seen as contagious places for COVID-19. Caregivers resorted to alternative care and self-management of childhood illnesses. COVID-19 vaccine hesitancy was a major concern among healthcare providers compared with community members at the time of vaccine roll-out in Lagos, Nigeria. Indirect impacts of COVID-19 lockdown included diminished household income, worsening food insecurity, mental health challenges for caregivers and reduced clinic visits for immunisation. Conclusion: The first wave of the COVID-19 pandemic in Lagos was associated with reductions in care seeking for children, clinic attendance for childhood immunisations and household income. Strengthening health and social support systems with context-specific interventions and correcting misinformation is crucial to building adaptive capacity for response to future pandemics

A theory for the impact of a wave breaking onto a permeable barrier with jet generation

We model a water wave impact onto a porous breakwater. The breakwater surface is modelled as a thin barrier composed of solid matter pierced by channels through which water can flow freely. The water in the wave is modelled as a finite-length volume of inviscid, incompressible fluid in quasi-one-dimensional flow during its impact and flow through a typical hole in the barrier. The fluid volume moves at normal incidence to the barrier. After the initial impact the wave water starts to slow down as it passes through holes in the barrier. Each hole is the source of a free jet along whose length the fluid velocity and width vary in such a way as to conserve volume and momentum at zero pressure. We find there are two types of flow, depending on the porosity, ß , of the barrier. If ß : 0 = ß < 0.5774 then the barrier is a strong impediment to the flow, in that the fluid velocity tends to zero as time tends to infinity. But if ß : 0.5774 = ß = 1 then the barrier only temporarily holds up the flow, and the decelerating wave water passes through in a finite time. We report results for the velocity and impact pressure due to the incident wave water, and for the evolving shape of the jet, with examples from both types of impact. We account for the impulse on the barrier and the conserved kinetic energy of the flow. Consideration of small ß gives insight into the sudden changes in flow and the high pressures that occur when a wave impacts a nearly impermeable seawall

Increasing conspicuity on night-time roads : Perspectives from cyclists and runners

Pedestrians and cyclists are at significant risk of being killed as a result of a collision with a vehicle at night-time because of their poor conspicuity. Retroreflective strips positioned on the moveable joints, in a biological motion configuration (biomotion), greatly enhance the night-time conspicuity of pedestrians and cyclists, but it is not clear how widely this strategy is adopted among those running and cycling under low light levels (dawn and dusk or at night). This study explored runners’ and cyclists’ beliefs about their own conspicuity, and the strategies they use to increase their conspicuity and safety under low light levels. Nine focus groups involving 50 participants (mean age = 39.5 ± 13.9 years) were held with individuals who ran and/or cycled under low light conditions or at night-time. The strategies that participants used to increase their conspicuity and enhance their personal safety, and the importance they placed on increased conspicuity to other road users at night was explored. Data were analysed thematically, with two main themes identified. Strategies describes the different approaches used to increase conspicuity when running or cycling in low light, some of which are ineffective. Importance describes how conspicuity relates to other considerations that influence cyclists and runners. While they may believe that conspicuity is essential for their safety, they may compromise their own conspicuity by prioritising style or comfort, or because they believe that being more conspicuous is of limited value because it cannot compensate for the behaviour of other road users. In summary, cyclists and runners are largely unaware of effective strategies to increase their night-time conspicuity, particularly the use of biomotion reflective strips. Garment manufacturers should ensure that conspicuity features (with supporting educative product information on labels) are incorporated into cyclists’ and runners’ clothing or accessories to improve wearer conspicuity and hence safety in low light conditions.</p

Direct observation of spin-polarised bulk bands in an inversion-symmetric semiconductor

Methods to generate spin-polarised electronic states in non-magnetic solids are strongly desired to enable all-electrical manipulation of electron spins for new quantum devices. This is generally accepted to require breaking global structural inversion symmetry. In contrast, here we present direct evidence from spin- and angle-resolved photoemission spectroscopy for a strong spin polarisation of bulk states in the centrosymmetric transition-metal dichalcogenide WSe$_2$. We show how this arises due to a lack of inversion symmetry in constituent structural units of the bulk crystal where the electronic states are localised, leading to enormous spin splittings up to $\sim\!0.5$ eV, with a spin texture that is strongly modulated in both real and momentum space. As well as providing the first experimental evidence for a recently-predicted `hidden' spin polarisation in inversion-symmetric materials, our study sheds new light on a putative spin-valley coupling in transition-metal dichalcogenides, of key importance for using these compounds in proposed valleytronic devices.Comment: 6 pages, 4 figure

Complex gastroschisis: a new indication for fetal surgery?

Gastroschisis (GS) is a congenital abdominal wall defect, in which the bowel eviscerates from the abdominal cavity. It is a non-lethal isolated anomaly and its pathogenesis is hypothesized to occur as a result of two hits: primary rupture of the ‘physiological’ umbilical hernia (congenital anomaly) followed by progressive damage of the eviscerated bowel (secondary injury). The second hit is thought to be caused by a combination of mesenteric ischemia from constriction in the abdominal wall defect and prolonged amniotic fluid exposure with resultant inflammatory damage, which eventually leads to bowel dysfunction and complications. GS can be classified as either simple or complex, with the latter being complicated by a combination of intestinal atresia, stenosis, perforation, volvulus and/or necrosis. Complex GS requires multiple neonatal surgeries and is associated with significantly greater postnatal morbidity and mortality than is simple GS. The intrauterine reduction of the eviscerated bowel before irreversible damage occurs and subsequent defect closure may diminish or potentially prevent the bowel damage and other fetal and neonatal complications associated with this condition. Serial prenatal amnioexchange has been studied in cases with GS as a potential intervention but never adopted because of its unproven benefit in terms of survival and bowel and lung function. We believe that recent advances in prenatal diagnosis and fetoscopic surgery justify reconsideration of the antenatal management of complex GS under the rubric of the criteria for fetal surgery established by the International Fetal Medicine and Surgery Society (IFMSS). Herein, we discuss how conditions for fetoscopic repair of complex GS might be favorable according to the IFMSS criteria, including an established natural history, an accurate prenatal diagnosis, absence of fully effective perinatal treatment due to prolonged need for neonatal intensive care, experimental evidence for fetoscopic repair and maternal and fetal safety of fetoscopy in expert fetal centers. Finally, we propose a research agenda that will help overcome barriers to progress and provide a pathway toward clinical implementation. © 2021 International Society of Ultrasound in Obstetrics and Gynecology