1D nanomaterials 2012

This is the final version of the article. Available from Hindawi Publishing Corporation via the DOI in this record

1D nanomaterials 2013

This is the final version of the article. Available from Hindawi Publishing Corporation via the DOI in this record.No abstrac

On Sensor-Based Ore Sorting

The high cost of mineral processing in mining industries keeps rising. Sensor-based ore sorting is key in helping the mining industries to sort out ore to help reduce the processing and production costs. With the implementation of sensor-based ore sorting at the primary stage, it assures of separating larger volumes of the barren gangue from the conveyor-transported ore before excessive handling and mixing occurs. Hence, this paper investigated and evaluated the deployment of the colour camera and the dual energy X-Ray sensors. The successful operation at 2.8 m/s and 3.2 m/s of conveyor speed, and relatively extreme positions of the air jet-based separation mechanism for the sorting proved robustness in separation of barren gangue from the ore feed

Obstetric medicine: Interlinking obstetrics and internal medicine

Medical problems account for almost 50% of all maternal deaths in South Africa. The most recent report of the National Committee on Confidential Enquiries into Maternal Deaths (NCCEMD) (2008 - 2010) stated that 40.5% of deaths were due to non-pregnancy-related infections, which are mostly HIV-related, and 8.8% were due to medical or surgical disorders. Obstetric physicians have a specific role in managing pregnant and postpartum women with medical problems and, in partnership with obstetricians, can contribute to reducing maternal morbidity and mortality. There are physiological changes in almost all systems in pregnancy. For example, changes in the cardiovascular, respiratory and haematological systems are particularly important when assessing the cause and management of medical problems in pregnant women. Such problems may be unique to pregnancy, exacerbated by pregnancy, or unrelated to pregnancy. They may be present prior to pregnancy, or present for the first time in pregnancy. Some medical problems are worsened by pregnancy. Pregnant women may improve or remain stable, or their disease may predictably or unpredictably deteriorate.This article discusses the role of obstetric physicians in managing medical problems in pregnant women. A case is described of a pregnant woman with common medical problems, resulting in a serious complication when treatment is interrupted. 

Polyurea-Functionalized Multiwalled Carbon Nanotubes

An in situ polycondensation approach was applied to functionalize multiwalled carbon nanotubes (MWNTs), resulting in various linear or hyperbranched polycondensed polymers [e.g., polyureas, polyurethanes, and poly(urea-urethane)-bonded carbon nanotubes]. The quantity of the grafted polymer can be easily controlled by the feed ratio of monomers. As a typical example, the polyurea-functionalized MWNTs were measured and characterized in detail. The oxidized MWNTs (MWNT-COOH) were converted into acyl chloride-functionalized MWNTs (MWNT-COCl) by reaction with neat thionyl chloride (SOCl2). MWNT-COCl was reacted with excess 1,6-diaminohexane, affording amino-functionalized MWNTs (MWNT-NH2). In the presence of MWNT-NH2, the polyurea was covalently coated onto the surfaces of the nanotube by in situ polycondensation of diisocyanate [e.g., 4,4‘-methylenebis(phenylisocyanate)] and 1,6-diaminohexane, followed by the removal of free polymer via repeated filtering and solvent washing. The coated polyurea content can be controlled to some extent by adjusting the feed ratio of the isocyanato and amino groups. The structure and morphology of the resulting nanocomposites were characterized by FTIR, NMR, Raman, confocal Raman, TEM, EDS, and SEM measurements. The polyurea-coated MWNTs showed interesting self-assembled flat- or flowerlike morphologies in the solid state. The signals corresponding to that of the D and G bands of the carbon nanotubes were strongly attenuated after polyurea was chemically tethered to the MWNT surfaces. Comparative experiments showed that the grafted polymer species and structures have a strong effect on the Raman signals of polymer-functionalized MWNTs

Discovery of Novel Cyclic Ethers with Synergistic Antiplasmodial Activity in Combination with Valinomycin

With drug resistance threatening our first line antimalarial treatments, novel chemotherapeutics need to be developed. Ionophores have garnered interest as novel antimalarials due to their theorized ability to target unique systems found in the Plasmodium-infected erythrocyte. In this study, during the bioassay-guided fractionation of the crude extract of Streptomyces strain PR3, a group of cyclodepsipeptides, including valinomycin, and a novel class of cyclic ethers were identified and elucidated. Further study revealed that the ethers were cyclic polypropylene glycol (cPPG) oligomers that had leached into the bacterial culture from an extraction resin. Molecular dynamics analysis suggests that these ethers are able to bind cations such as K+, NH4+ and Na+. Combination studies using the fixed ratio isobologram method revealed that the cPPGs synergistically improved the antiplasmodial activity of valinomycin and reduced its cytotoxicity in vitro. The IC50 of valinomycin against P. falciparum NF54 improved by 4–5-fold when valinomycin was combined with the cPPGs. Precisely, it was improved from 3.75 ± 0.77 ng/mL to 0.90 ± 0.2 ng/mL and 0.75 ± 0.08 ng/mL when dosed in the fixed ratios of 3:2 and 2:3 of valinomycin to cPPGs, respectively. Each fixed ratio combination displayed cytotoxicity (IC50) against the Chinese Hamster Ovary cell line of 57–65 µg/mL, which was lower than that of valinomycin (12.4 µg/mL). These results indicate that combinations with these novel ethers may be useful in repurposing valinomycin into a suitable and effective antimalarial

A student's guide to decolonising linguistics: Enabling teaching staff to empower students

The student voice has been at the forefront of decolonisation campaigns such as ‘Why is my curriculum white’ (UCL) and the ‘Rhodes must fall’ campaign that originated in Cape Town. This reflects a strong desire – and recognition of the need – for change from the people at the receiving end of higher education. Students typically comprise a more diverse population than those teaching them and producing the research they learn about, and they enter the system and see it with fresh eyes. These students have looked at our current way of doing things, and found it wanting. Much has been said and written about the decolonisation and diversification of HE curricula (e.g. Arday & Mirza 2019). Much good work has begun, attitudes are beginning to change, and awareness is high (Author 3, 2020). However, systemic issues (precarity, workload, inertia) combine with a lack of expertise and confidence among teaching staff regarding race and equality, meaning that change is slow to come (Author 3, 2020). In particular, the ‘broken pipeline’ (Leading Routes) means that precisely those who should be involved with decolonisation work are often not the ones with the power to effect it. This paper, from the undergraduate student perspective, raises several important questions and opens a conversation about how students can be agents of change in a meaningful, ongoing process. We distinguish between the processes of diversification and decolonisation. The former is an absolute requirement for all universities right now, and is the locus of much of the excellent work that has been done so far. We have to acknowledge that decolonisation, a far deeper process, may not be truly possible without a fundamental uprooting of our discipline, given its roots within whiteness and in a Western, Global North-centred academia. This is often especially true of ‘formal’ linguistic modules such as those teaching syntactic, semantic or phonological theory. There, a position of supposed neutrality and level of abstraction masks the same eurocentrism that may be more evident in a module on sociolinguistics that explicitly discusses specific language communities. Furthermore, while many teaching staff themselves research languages other than English and incorporate this into their teaching, a lack of available resources means that it may be much more labour-intensive and perhaps not even possible to avoid also having a textbook that undermines this work. However, this problematisation is rooted in the assumption that the institution or teaching staff are the primary agents of change. Work done by Author 3 and others (e.g. Thomas & Jivraj 2020) highlights the positive experience of students who can engage on an equal footing with diversification work. As students approaching the end of our first year of undergraduate study in linguistics, we have regularly sought a deeper or more global perspective than our course was able to provide. For example, topics covering language relatedness and language contact did not go beyond Indo-European languages, creole languages were not incorporated, and the morphology or syntax of signed languages was not part of the syllabus. We recognise, of course, that not all topics can be covered in first year modules, but we argue that this is symptomatic of a more general problem: ‘introductory’ topics are the last (and least likely) to be diversified. This is partly due to the systemic pressures already mentioned (for example, ‘Intro Syntax’ is more likely to be team taught, or taught by different people from year to year, making it harder to make changes or plan for the future), and partly the idea that the theory, at least, is neutral. As students from an African background where 3 or 4 languages are regularly spoken at home, our interest going into linguistics naturally included the sociolinguistics of African languages, colonialism and marginalised countries. Typically, however, any mention of languages beyond Europe or of varieties like AAL is relegated to optional extra reading, and African languages were even discussed in derogatory terms because the texts were rather old (but still used because they are ‘classic’ texts). This can be especially damaging in first year modules, where a feeling of alienation or, conversely, involvement from the start can set the tone for future study. This is the basis of our call to action. Where the progress made from the institution or the lecturer is just at the start of the journey to equality, and other pressures mean that change is necessarily slow, students can and should be able to contribute. This is especially true where students may have some level of cultural expertise (e.g. a non-Indo-European home language or a home country different from the others in the group). The power dynamic in a classroom is clearly unequal, and furthermore an awareness from the lecturer of their own position as white, able-bodied, European, etc can produce a defensiveness or lack of confidence in guiding fruitful conversations. However, if the space is opened up to formally encourage students to share their experiences without putting the burden of change on them, a collaborative approach can lead to genuine change. Two examples of introductory linguistics modules are presented. One was designed to be inclusive from the bottom up, and the other is a long-standing introductory generative syntax module. Lessons learnt from the differences between student reactions to the measures proposed by the lecturer are discussed, along with the marked difference in engagement with social justice issues. We relate these examples to the 3D Pedagogy model developed by Gabriel (2019) which emphasises democratisation of the classroom and ask how teaching staff can empower students. We consider the type of training that would be beneficial for enabling potentially difficult conversations; assessment types that allow students to contribute to the curriculum; and what kind of support students would need in order to feel safe yet empowered

Identification of Antimycobacterial Natural Products from a Library of Marine Invertebrate Extracts

Tuberculosis (TB) remains a public health crisis, requiring the urgent identification of new anti-mycobacterial drugs. We screened several organic and aqueous marine invertebrate extracts for their in vitro inhibitory activity against the causative organism, Mycobacterium tuberculosis. Here, we report the results obtained for 54 marine invertebrate extracts. The chemical components of two of the extracts were dereplicated, using 1H NMR and HR-LCMS with GNPS molecular networking, and these extracts were further subjected to an activity-guided isolation process to purify the bioactive components. Hyrtios reticulatus yielded heteronemin 1 and Jaspis splendens was found to produce the bengamide class of compounds, of which bengamides P 2 and Q 3 were isolated, while a new derivative, bengamide S 5, was putatively identified and its structure predicted, based on the similarity of its MS/MS fragmentation pattern to those of other bengamides. The isolated bioactive metabolites and semi-pure fractions exhibited M. tuberculosis growth inhibitory activity, in the rang

Novel South African rare actinomycete kribbella speibonae Strain SK5: A prolific producer of hydroxamate siderophores including new dehydroxylated congeners

In this paper, we report on the chemistry of the rare South African Actinomycete Kribbella speibonae strain SK5, a prolific producer of hydroxamate siderophores and their congeners. Two new analogues, dehydroxylated desferrioxamines, speibonoxamine 1 and desoxy-desferrioxamine D1 2, have been isolated, together with four known hydroxamates, desferrioxamine D1 3, desferrioxamine B 4, desoxy-nocardamine 5 and nocardamine 6, and a diketopiperazine (DKP) 7. The structures of 1–7 were characterized by the analysis of HRESIMS and 1D and 2D NMR data, as well as by comparison with the relevant literature