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The inability to thoroughly examine diatom type material existing only in resin-mounted permanent slides is a common frustration for diatomologists. Here, we present an efficient, inexpensive, and straightforward technique to extract siliceous exoskeletons of diatoms from permanent slides prepared with commonly used mounting media. Van Heurck's slide constituting an isotype duplicate of Proschkinia bulnheimii var. belgica, an entity with an uncertain taxonomic status, was deconstructed to allow thorough examination using scanning electron microscopy. Numerous specimens of the taxon, including intact frustules and specimens with complete areola occlusions, were recovered and documented. The extracted diatom material was sufficient to prepare two scanning electron microscopy specimens and reconstruct the permanent slide. The proposed approach may help overcome many of the taxonomic bottlenecks associated with the low resolution of information provided by older diatom descriptions and permanent slide observations.

Freshwater red algae have been collected on the African continent since the early 1800s. However, the collections have been sparse and geographically restricted. The present study sought to bring t...

Worldwide the use of pesticides has increased, especially in the industry and agriculture sector even though they contain highly toxic substances. The use of pesticides has various negative effects on the aquatic ecosystem and organisms within these ecosystems. The paper aimed to assess the effects of increased concentrations of malaria vector control insecticides (Dichlorodiphenyltrichloroethane (DDT) and Deltamethrin (DTM)) on the freshwater diatom community structure using a microcosm approach as well as determine whether a mixture (DDT 1:1 Deltamethrin) exposure will have a greater influence on the diatom community when compared to single exposures of these insecticides. Diatoms were exposed to a high and low concentration (based on LC50 data for freshwater Xenopus laevis from the USEPA Ecotox database) of DDT, DTM and a mixture in lentic microcosms over a total period of 28 days. Results indicated that irrespective of exposure concentrations, DDT, DTM and a mixture had negative effects on the diatom community including functionality and vitality as these insecticides induced changes to their chloroplasts. There was an increased percentage dead cells for all exposures compared to the control, with the insecticides having a phototoxic effect on the diatom community. Exposure to the selected insecticides caused a significant decrease in some diatom metrics indicating the negative effects these insecticides have on the diatom metrics. Therefore, diatoms may prove to be useful as bio-indicators in ecotoxicology studies when assessing the effects of any insecticide exposures.

Diatoms are siliceous micro-algae and have been used with increasing frequency as bioindicators in aquatic ecosystems. Typically, European diatom indices have been modified and augmented with data on taxa endemic to and commonly found in other parts of the world. In order to further test the application of diatom indices, water quality and diatom sampling were performed in the Bloukrans River system, Eastern Cape Province of South Africa. Nine sites with contrasting water quality were sampled along the length of the river in February, May and July 2018. Multivariate statistical analysis (Canonical Correspondence Analysis) was employed to elucidate spatiotemporal differences in diatom community structure. Canonical correspondence analysis indicated that differences in diatom community assemblages were best explained by dissolved oxygen, temperature, nitrate, conductivity and phosphate. Diatom-based indices incorporated in OMNIDIA software were also applied to assess the integrity of the water quality as indicated by diatom communities. Several foreign indices (e.g. the trophic diatom index (TDI), biological diatom index (BDI)) and the South African Diatom Index (SADI) were used in the study. The SADI demonstrated that the Bloukrans River was impacted and had significant correlations with water quality variables (p

Monitoring of wetland ecosystems is crucial as these ecosystems provide numerous services and resources to both humans and the biota found therein. Wetlands are characterised by variations in inundation time and depth and therefore it is often difficult to make use of invertebrates and fish as biological indicators. Diatoms may be used for monitoring of wetland ecosystems as they are widely distributed, are microscopic with few habitat restrictions, communities are species rich and they respond rapidly to environmental changes. Very little information is available on wetland diatom communities in South Africa. Wetland ecosystems include Ramsar sites such as Lake Sibaya which faces increased forestry and rural development within the lake's catchment area. Therefore, this study aimed to determine the diatom community structure of Lake Sibaya and its response to changes in water quality. Water and diatom samples were collected from four sites in Lake Sibaya during August 2015, December 2015 and February 2016. All samples were collected and analysed according to standard methodologies. From the results it was clear that the lake had a lower diatom diversity than that described in a previous study in 1966, with Cocconeis placentula, Gomphonema sp., Epithemia adnata and Nitzschia sp. being the dominant taxa. Both the diatom community structure and measured water quality parameters showed the lake to be nutrient enriched. However, as nutrients accumulate in wetlands it is unknown whether the increased nutrients arise from anthropogenic disturbances or natural sources.

Background: Although the Kruger National Park (KNP) is a protected area, it is not exempted from anthropogenically induced impacts, which often compromise river water flow and quality. Measures of river water quality in South Africa have conventionally been based on water chemistry as well as different ecological indicator groups such as fish and macroinvertebrates. Diatoms have been shown to be useful indicators of changes in water quality resulting from pollution and land-use impacts.Objectives: To determine the applicability of diatoms for hind-casting water quality in the KNP and to compare recent diatom community composition with those from the 1980s.Methods: In this study, pH and electrical conductivity (EC) were used to evaluate temporal changes in water quality of three rivers within the KNP. Additionally, we made use of historic diatom samples from three of the five perennial rivers to evaluate if diatom communities reflected changes in water conditions between 1983 and 2015.Results: Diatom community structure was significantly different between 1983 and 2015. Diatom-based index scores (SPI) indicated an improvement in water quality for the Letaba and Olifants rivers.Conclusion: Diatoms were shown to be useful indicators of current water quality and are also useful for determining temporal changes.

The current study focuses on four species from the primarily marine diatom genus Craspedostauros that were observed growing attached to numerous sea turtles and sea turtle-associated barnacles from Croatia and South Africa. Three of the examined taxa, C. danayanus sp. nov., C. legouvelloanus sp. nov., and C. macewanii sp. nov., are described based on morphological and, whenever possible, molecular characteristics. The new taxa exhibit characters not previously observed in other members of the genus, such as the presence of more than two rows of cribrate areolae on the girdle bands, shallow perforated septa, and a complete reduction of the stauros. The fourth species, C. alatus, itself recently described from museum sea turtle specimens, is reported for the first time from loggerhead sea turtles rescued in Europe. A 3-gene phylogenetic analysis including DNA sequence data for three sea turtle-associated Craspedostauros species and other marine and epizoic diatom taxa indicated that Craspedostauros is monophyletic and sister to Achnanthes. This study, being based on a large number of samples and animal specimens analyzed and using different preservation and processing methods, provides new insights into the ecology and biogeography of the genus and sheds light on the level of intimacy and permanency in the host-epibiont interaction within the epizoic Craspedostauros species.

Petalonema alatum (Borzì ex Bornet & Flahault) Correns is a nitrogen fixing, subaerial cyanobacterium characterized by a blue-green trichome surrounded by a very broad, lamellated mucous sheath. It typically grows on dripping limestone rocks in temperate regions, but it has also been observed in some calcareous lakes and limestone springs. Although the species is known to be present in the Americas, Europe and Asia, no records could be found for its presence in Africa. In the last decade, it was sampled twice from rock surfaces in cave overhangs in the Free State Province of South Africa, representing a first record of its presence in Africa. A taxonomic description, microscope images as well as detailed geographical distributions of P. alatum are provided.

Supplemental Digital Content is available in the text., The Alderson striatal phantom is frequently used to assess 123I-FP-CIT (Ioflupane) image quality and to test semi-quantification software. However, its design is associated with a number of limitations, in particular: unrealistic image appearances and inflexibility. A new physical phantom approach is proposed on the basis of subresolution phantom technology. The design incorporates thin slabs of attenuating material generated through additive manufacturing, and paper sheets with radioactive ink patterns printed on their surface, created with a conventional inkjet printer. The paper sheets and attenuating slabs are interleaved before scanning. Use of thin layers ensures that they cannot be individually resolved on reconstructed images. An investigation was carried out to demonstrate the performance of such a phantom in producing simplified 123I-FP-CIT uptake patterns. Single photon emission computed tomography imaging was carried out on an assembled phantom designed to mimic a healthy patient. Striatal binding ratio results and linear striatal dimensions were calculated from the reconstructed data and compared with that of 22 clinical patients without evidence of Parkinsonian syndrome, determined from clinical follow-up. Striatal binding ratio results for the fully assembled phantom were: 3.1, 3.3, 2.9 and 2.6 for the right caudate, left caudate, right putamen and right caudate, respectively. All were within two SDs of results derived from a cohort of clinical patients. Medial–lateral and anterior–posterior dimensions of the simulated striata were also within the range of values seen in clinical data. This work provides the foundation for the generation of a range of more clinically realistic, physical phantoms.

This article presents a historical overview of estuarine microphytobenthos (MPB) research in South Africa published over the period 1950 to the present, highlighting major milestones, challenges an...

Luisa Riato was supported by a Coaltech Research Association Research Fellowship. J.C. Taylor is the recipient of South African National Research Foundation (NRF) incentive funding.

Two new freshwater species of Achnanthidium Kutzing are described from Eastern Ghats Mountain range of Peninsular India based on light and scanning electron microscopy observations. Achnanthidium initium sp. nov. belongs to the group of Achnanthidium taxa that have terminal raphe fissures curved to opposite sides of the valve. This taxon is characterized by distinctive fascia, raphe endings extending to the valve margin, lineate distal raphe endings and 2-5 linear areola per striae. Achnanthidium linannulum sp. nov. belongs to the group of Achnanthidium taxa with terminal raphe fissures curved to the same side of the valve. This species is characterized by the presence of occluded areolae near the margin, striae orientation and the weakly bent internal distal ends of the raphe. These new species are known only from their type locality, oligotrophic Masilla Waterfalls from Kolli Hills, Eastern Ghats.

Cholnoky described several new Surirella taxa from Africa and we have re-investigated this material. As many other of his contemporary authors, especially in the case of description of new African diatoms, Cholnoky did not indicate holotypes. In the present paper original materials are re-evaluated, lectotypes and a holotype are designated and also epitypes whenever it was appropriate. Taxa later transferred to Stenopterobia have not been taken into account. A short description of the seven species concerned (Surirella anassae, S. chasei, S. coei, S. oliffii, S. ostentata = Surirella ovata var. africana, S. pseudotenuis and S. pseudothienemannii) is given based on the original light microscopic descriptions. Additional morphological information based on scanning electron microscopy is added if available. The presently known ecology and distribution of the taxa is given as are other remarks, based on own observations. For each of the seven taxa Cholnoky's original drawings are presented, which were later re-drawn for publication and which are kept in the archive of the South African National Diatom Collection. The results are discussed referring to the outcome of the digitization project of African Surirellaceae (diatoms, microscopic algae) in the frame of the African Plants Initiative.

Natural lakes are rarely found in South Africa and are usually restricted to coastal regions. One of the larger coastal lakes is Lake Sibaya, which is situated in North-Eastern Kwa-Zulu Natal, a subtropical summer rainfall region. In 1966 a survey of this and other smaller lakes connected to the Lake Sibaya system was conducted and diatom samples were collected, of which three were examined by R.E.M. Archibald, and from which nine new species were described. Archibald illustrated these new taxa using line drawings; the interpretation of such illustrations for species identification is sometimes difficult. For this reason we have re-examined the type material with the aim of producing light microscope (LM) and scanning electron microscope (SEM) micrographs of the species in question. All nine taxa described and illustrated by Archibald were found again in the type slides and photographed from the holotype slides using LM. Unfortunately the preserved type material was stored in un-buffered formalin and had degraded to a point where it could no longer be used for SEM. Additional desiccated samples collected during later expeditions between 1966 and 1972 were selected, based on similarity of locality and substratum, and used to obtain SEM micrographs. Again, all taxa could be documented from material in these additional samples. Of the nine taxa described, we transferred four to more appropriate genera, as they were originally described as species of Achnanthes and Navicula. Although Archibald’s line drawings were detailed and accurate, it was necessary to document these types using LM and SEM in order to make accurate designations at generic level and to facilitate identification of these taxa if found in other localities

Background and aims – Large-celled Eunotia species from tropical central Africa are documented in order to define morphological variation within species and to describe new or poorly documented taxa.Methods – Samples were collected from the Congo River between Kisangani and Bumba in the Democratic Republic of the Congo. These samples were prepared for diatom analysis and examined according to standard methods and documented using both light and scanning electron microscopy.Key results – A single population of Eunotia zygodon is used to demonstrate the high degree of change in gross cell morphology during its life cycle, changes previously observed in cultures of this genus. Cells of this taxon from each extremity of the reproductive cycle could be, and probably often were, placed in discrete taxa during sample analysis, especially as this taxon occurs rather infrequently. We also describe Eunotia leonardii as new to science. It has an undulate valve margin and is closely related to Eunotia serra and Eunotia georgii but differs in respect to overall cell size and the structure of the terminal raphe endings. The bi-undulate Eunotia papilio var. africana is raised to the rank of species and named Eunotia fuseyi as it is clearly a discrete taxon from E. papilio s. str.

Water quality and algal populations in the Vaal River Barrage Reservoir have been monitored extensively for many decades, because of its importance as a water source for the most densely populated area in South Africa. Although Aulacoseira granulata (Ehrenberg) Simonsen is frequently found and at it times dominates algal assemblages in the Barrage, Aulacoseira ambigua (F.Meister) Tuji & D.M.Williams has never before been recorded at this locality. During a countrywide proficiency-testing scheme for algae counting, coordinated by Rand Water, spiral-shaped diatom colonies with distinctly curved cells were detected during May 2015. Upon investigation, it was found that the spiral colonies were Aulacoseira ambigua f. japonica, its presence in the fresh waters of South Africa being recorded for the first time. Since their first appearance during May 2015, colonies of Aulacoseira ambigua f. japonica have been constantly present in the surface waters of the Barrage. Their presence at this site can be linked to increasing eutrophication in the Vaal River, because the spiral form is known to prefer eutrophic conditions. Centric diatoms rarely form spiral colonies and there is some confusion in the literature as to the identity of this particular form, therefore in this paper we discuss this taxon, its nomenclature and ecological significance.Keywords: algae, curved diatom cells, phytoplankton, spiral colonies, Vaal River Barrage Reservoir

In this paper we describe Navicula nielsfogedii sp. nov., a commonly occurring diatom through central and southern Africa and distributed from the sub-tropical zones of South Africa to tropical central Africa. We have examined the material of the most closely related species described from Africa, Navicula feuerbornii f. africana Foged and suggest that this species may be conspecific with Navicula heimansioides Lange-Bertalot and to have no link to the taxon N. feuerbornii Hustedt sensu Simonsen. With reference to Navicula feuerbornii f. africana we also discuss the changes over time in diatom species concepts, what we have dubbed 'species concept drift', and the consequences this holds for accurately identifying diatom taxa. As the newly described species is widely distributed and common in some samples from tropical and subtropical Africa we conclude that it may be a useful additional indicator organism for water quality monitoring in the region.

Rivers are impacted by pollutants from anthropogenic activities such as urbanisation and agricultural practices. Whilst point source pollution has been widely studied and in some cases remediated, non-point pollutant sources remain pervasive, particularly in developing countries that lack economic and human specialist capacity. Monitoring of pollution levels in many regions is additionally challenged by a lack of robust indicators for nitrogen inputs, however, diatom community indices and analysis of variation in microphytobenthos (MBP) stable isotope analysis variations have potential. The present study investigates variations and utilities in benthic diatom indices and MPB δ15N along different river sections (n = 31) of an austral river between two seasons (wet and dry), testing for relationships with key environmental variables (physical, water and sediment), in the context of N monitoring. One hundred and eighteen diatom taxa belonging to 36 genera were identified, with physical (water flow), water (nitrate, P and total dissolved solids) and sediment (B, Ca, Cr, Na, N, P, SOM, Pb and Zn) variables correlating to one or more of the 12 diatom indices presented. In particular, Biological Diatom Index, Biological Index of Water Quality, Central Economic Community, Index of Artois-Picardie Diatom (IDAP) and Sladecek's Index were strongly explained by sediment variables, whilst Descy's Pollution Index and Schiefele and Schreiner's Index were explained by water and physical variables. Whilst MPB δ15N were within the “no impact” level in the wet and dry seasons at reference (i.e. unpolluted) sites, all sites located in agricultural or urban areas, and downstream of sewage discharges, had a wider range that encompassed increasing organic impacts (“inorganic impacts” to high “organic impacts”). Temperature and turbidity (negative), as well as dissolved oxygen, waterway width and depth (positive), significantly affected MPB δ15N, whilst effects of chemistry variables were less apparent. Overall, we found that MPB δ15N signatures were significantly correlated with Trophic Diatom Index, the Specific Pollution Sensitivity Index and the Artois-Picardie Diatom Index, suggesting the utility of diatoms and MPB δ15N in assessments of aquatic pollution. In turn, MPB δ15N values are strong indicators of N pollution across spatial and seasonal gradients. Thus, the results showed the effects of sediment variables on diatoms to be strong, indicating that sediment rather than water characteristics more strongly structure diatom communities. Thus, sediment variables should be sampled when conducting bioassessment studies.

Despite more than 150 years of diatom research in India, cymbelloid taxa have rarely been investigated when compared to the other parts of the world. A new freshwater species of Encyonema Kutzing was discovered from the mountain ranges of Peninsular India and is described based on light and scanning electron microscopy observations. This paper provides a comparison of the new taxa with morphologically similar taxa of the genus Encyonema. Encyonema keshrii, sp. nov., is characterized on the basis of distinctive morphological characters including valve and apex shape as well as striae density. Enccyonema keshrii, sp. nov., is found to be a wide spread taxon with distribution across the Eastern Ghats, Western Ghats and the Eastern Himalayas of Indian subcontinent.

A first survey was done on algae present in the Sundays River from its source to its confluence with the sea. Species found in the upstream sections of the river included indicators of good water quality, but the quality deteriorated downstream with peaks in algal abundance being ascribed to peaks in nutrient concentrations. Cyanobacteria and euglenoids were present in the upper and middle reaches of the river, but were absent downstream. Dinoflagellates became more important downstream, especially in the estuary. Dominant species, reaching high concentrations along the river, included Nitzschia frustulum, Nitzschia capitellata, Carteria klebsii, Chlorella vulgaris and Anabaena species. The presence of the diatom Eolimna comperei is a first record of its occurrence in South Africa. The Sundays River can be described as a brackish, hard water system with high nutrient concentrations in certain sections. The most important contributors to high nutrient concentrations were point sources in the vicinity of towns along the river banks, as well as diffuse sources contributing to high nitrogen concentrations in the fertile Sundays River valley. Increasing salinities were due to pollution, evaporation and agricultural activities in the valley

Semi-quantification methods are well established in the clinic for assisted reporting of (I123) Ioflupane images. Arguably, these are limited diagnostic tools. Recent research has demonstrated the potential for improved classification performance offered by machine learning algorithms. A direct comparison between methods is required to establish whether a move towards widespread clinical adoption of machine learning algorithms is justified. This study compared three machine learning algorithms with that of a range of semi-quantification methods, using the Parkinson’s Progression Markers Initiative (PPMI) research database and a locally derived clinical database for validation. Machine learning algorithms were based on support vector machine classifiers with three different sets of features: Semi-quantification methods were based on striatal binding ratios (SBRs) from both putamina, with and without consideration of the caudates. Normal limits for the SBRs were defined through four different methods: Each machine learning and semi-quantification technique was evaluated with stratified, nested 10-fold cross-validation, repeated 10 times. The mean accuracy of the semi-quantitative methods for classification of local data into Parkinsonian and non-Parkinsonian groups varied from 0.78 to 0.87, contrasting with 0.89 to 0.95 for classifying PPMI data into healthy controls and Parkinson’s disease groups. The machine learning algorithms gave mean accuracies between 0.88 to 0.92 and 0.95 to 0.97 for local and PPMI data respectively. Classification performance was lower for the local database than the research database for both semi-quantitative and machine learning algorithms. However, for both databases, the machine learning methods generated equal or higher mean accuracies (with lower variance) than any of the semi-quantification approaches. The gain in performance from using machine learning algorithms as compared to semi-quantification was relatively small and may be insufficient, when considered in isolation, to offer significant advantages in the clinical context.

AIM A national audit of quantitative thyroid uptake imaging was conducted by the Nuclear Medicine Software Quality Group of the Institute of Physics and Engineering in Medicine in 2014/2015. The aims of the audit were to measure and assess the variability in thyroid uptake results across the UK and to compare local protocols with British Nuclear Medicine Society (BNMS) guidelines. PARTICIPANTS AND METHODS Participants were invited through a combination of emails on a public mailbase and targeted invitations from regional co-ordinators. All participants were given a set of images from which to calculate quantitative measures and a spreadsheet for capturing results. The image data consisted of two sets of 10 anterior thyroid images, half of which were acquired after administration of Tc-pertechnetate and the other half after administration of I-iodide. Images of the administration syringes or thyroid phantoms were also included. RESULTS In total, 54 participants responded to the audit. The median number of scans conducted per year was 50. A majority of centres had at least one noncompliance in comparison with BNMS guidelines. Of most concern was the widespread lack of injection-site imaging. Quantitative results showed that both intersite and intrasite variability were low for the Tc dataset. The coefficient of quartile deviation was between 0.03 and 0.13 for measurements of overall percentage uptake. Although the number of returns for the I dataset was smaller, the level of variability between participants was greater (the coefficient of quartile deviation was between 0.17 and 0.25). CONCLUSION A UK-wide audit showed that thyroid uptake imaging is still a common test in the UK. It was found that most centres do not adhere to all aspects of the BNMS practice guidelines but that quantitative results are reasonably consistent for Tc-based scans.

U.S. Army Special Operations Forces (SOF) soldiers deploy frequently and conduct military operations through special warfare and surgical strike capabilities. Tasks required to execute these capabilities may induce physical and mental stress and have the potential to degrade soldier physiological status. No investigations have longitudinally characterized whether combat deployment alters anthropometrics or biochemical markers of physiological status in a SOF population of frequent deployers.Effects of modern combat deployment on longitudinal changes in anthropometrics and physiological status of elite U.S. Army SOF soldiers (n = 50) were assessed. Changes in measures of body composition, grip strength, physiological status, and health behaviors from baseline to postdeployment were determined with paired t test and McNemar's statistic. Baseline measures were obtained between 4 and 8 weeks before deployment. Deployment length was a uniform duration of time between 3 and 6 months (all soldiers completed the same length of deployment). Post hoc analyses determined change in body mass within quartiles of baseline body mass with paired t test and associations between change in sex hormone-binding globulin (SHBG) and change in body mass with correlation coefficient. The study was approved by the Human Use Review Committee at the U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts.In response to deployment, increases in lean mass (77.1 ± 7.6 to 77.8 ± 7.5 kg), maximum grip strength (57.9 ± 7.2 to 61.6 ± 8.8 kg), and conduct of aerobic (156 ± 106 to 250 ± 182 minutes/week) and strength training (190 ± 101 to 336 ± 251 minutes/week) exercise were observed (p0.05). Increases in serum SHBG (35.42 ± 10.68 to 38.77 ± 12.26 nmol/L) and decreases in serum cortisol (443.2 ± 79.3 to 381.9 ± 111.6 nmol/L) were also observed (p0.05). Body mass changes were dependent on baseline body mass. Soldiers in the lowest quartile of baseline body mass increased body mass (75.6 ± 2.6 vs. 76.6 ± 2.8 kg, p = 0.03), as did those in the second quartile (81.6 ± 2.0 vs. 83.7 ± 3.5 kg, p = 0.02). Those in the third quartile also tended to increase body mass (89.2 ± 2.6 vs. 90.9 ± 3.3 kg, p = 0.05), while those in the upper quartile tended to decrease body mass (98.5 ± 3.6 vs. 96.7 kg, p = 0.06). Change in SHBG was inversely correlated with change in body mass (r = -0.33, p = 0.02). There were no changes in fat mass, body fat percentage, waist circumference, neck circumference, total testosterone, calculated bioavailable or free testosterone, high-sensitivity C-reactive protein, tumor necrosis factor-α, interleukin-1β, or interleukin-6. Inflammatory markers were skewed toward lower values.Overall, physiological status of elite SOF soldiers characterized by multiple prior deployments was minimally impacted by combat deployment, in the absence of major unit casualties. The majority experienced some adaptive changes, including increased lean mass, grip strength, time spent engaged in exercise, and decreased levels of the stress hormone cortisol. Mechanisms contributing to inverse correlations between change in SHBG and change in body mass may be further clarified. Future investigations may also more fully characterize the degradation and optimization of health and physiological status of SOF training and deployment cycles with in-theater data collection and repeated measures.

Summary Diatom taxa in India were first documented by Ehrenberg and subsequently many studies have focused on the Western Ghats and Himalayan mountains while other regional environments were rarely explored. In the current study, the freshwater environs of the saline Lonar Crater Lake were investigated and two new Nitzschia species have been described. Nitzschia kociolekii sp. nov. and Nitzschia tripudio sp. nov. were sampled from bird feeding ponds associated with Lonar Lake. The morphological characters of the new species are similar to N. amphibia and N. frustulum but differ in terms of striae pattern, polymorphic areolae development, fibula and stria density. In addition, larger specimens of N. williamsii, a recently described taxon from Bangalore wetlands of Peninsular India, were found in a waterfalls flowing into Lonar Lake. All three taxa are freshwater diatoms and are possibly endemic to Peninsular India.

Measurements of SeHCAT (tauroselcholic [75selenium] acid) retention have been used to diagnose bile acid malabsorption for a number of years. In current UK practice the vast majority of centres calculate uptake using an uncollimated gamma camera. Because of ever-increasing demands on gamma camera time, a new 'probe' detector was designed, assembled and commissioned. To validate the system, nine patients were scanned at day 0 and day 7 with both the new probe detector and an uncollimated gamma camera. Commissioning results were largely in line with expectations. Spatial resolution (full-width 95% of maximum) at 1 m was 36.6 cm, the background count rate was 24.7 cps and sensitivity at 1 m was 720.8 cps/MBq. The patient comparison study showed a mean absolute difference in retention measurements of 0.8% between the probe and uncollimated gamma camera, and SD of ± 1.8%. The study demonstrated that it is possible to create a simple, reproducible SeHCAT measurement system using a commercially available scintillation detector. Retention results from the probe closely agreed with those from the uncollimated gamma camera.

This paper provides a description of the zooplankton and epiphytic diatom communities of permanent and temporary freshwater pans in the Mpumalanga Highveld region of South Africa. Few studies have investigated the biota of pans in this area, which is seriously threatened by mining and agricultural development. Nineteen pan sites within a 20 kmradius covering a wide range of water chemistries were sampled once for zooplankton, epiphytic diatoms and water physico-chemical data in 2009. Collected zooplankton and diatom samples were identified to species or genus level. Many of the zooplankton taxa reported in this study were not recorded in similar pan studies in South Africa and southern Africa. The study revealed a difference among the compositions of zooplankton and diatom communities between temporary pans and permanent pans. Zooplankton found exclusively in freshwater temporary pans included cladocerans (Megafenestra aurita and Scapholeberis kingi), calanoids (Mesocyclops major and Thermodiaptomus mixtus), a cyclopoid (Acanthocyclops vernalis) and a rotifer (Platyias quadricornis). Permanent pans were characterized by taxa such as cladocerans (Ceriodaphnia rigaudi and Dunhevedia crassa), a calanoid (Metadiaptomus transvaalensis), cyclopoids (Paracyclops fimbriatus and Eucyclops gibsoni) and rotifers (Brachionus dimidiatus and Brachionus plicatilis). The most commonly occurring diatom taxa in temporary pans included taxa indicative of slightly acidic to circumneutral, dystrophic and nutrient-poor waters such as Nitzschia acidoclinata, Gomphonema gracile and Eunotia bilunaris. Permanent pan assemblages were characterized by taxa typical of saline waters, including Nitzschia frustulum, Amphora veneta and Planothidium engelbrechtii. Species of the genera Pinnularia and Eunotia were almost totally absent from permanent pans.Key words: zooplankton, epiphytic diatoms, pans, wetlands, South Africa.

Machine learning promises much in the field of radiology, both in terms of software that can directly analyse patient data and algorithms that can automatically perform other processes in the reporting pipeline. However, clinical practice remains largely untouched by such technology. This article highlights what we consider to be the major obstacles to widespread clinical adoption of machine learning software, namely: representative data and evidence, regulations, health economics, heterogeneity of the clinical environment and support and promotion. We argue that these issues are currently so substantial that machine learning will struggle to find acceptance beyond the narrow group of applications where the potential benefits are readily evident. In order that machine learning can fulfil its potential in radiology, a radical new approach is needed, where significant resources are directed at reducing impediments to translation rather than always being focused solely on development of the technology itself.

International audience; Contaminant-related stress on aquatic biota is difficult to assess when lethal impacts are not observed. Diatoms, by displaying deformities (teratologies) in their valves, have the potential to reflect sub-lethal responses to environmental stressors such as metals and organic compounds. For this reason, there is great interest in using diatom morphological aberrations in biomonitoring. However, the detection and mostly the quantification of teratologies is still a challenge; not all studies have succeeded in showing a relationship between the proportion of abnormal valves and contamination level along a gradient of exposure. This limitation in part reflects the loss of ecological information from diatom teratologies during analyses when all deformities are considered. The type of deformity, the severity of aberration, species proneness to deformity formation, and propagation of deformities throughout the population are key components and constraints in quantifying teratologies. Before a metric based on diatom deformities can be used as an indicator of contamination, it is important to better understand the “ecological signal” provided by this biomarker. Using the overall abundance of teratologies has proved to be an excellent tool for identifying contaminated and non-contaminated environments (presence/absence), but refining this biomonitoring approach may bring additional insights allowing for a better assessment of contamination level along a gradient. The dilemma: are all teratologies significant, equal and/or meaningful in assessing changing levels of contamination? This viewpoint article examines numerous interrogatives relative to the use of diatom teratologies in water quality monitoring, provides selected examples of differential responses to contamination, and proposes solutions that may refine our understanding and quantification of the stress. This paper highlights the logistical problems associated with accurately evaluating and interpreting teratologies and stimulates more discussion and research on the subject to enhance the sensitivity of this metric in bioassessments.

This study focused on the spring-fed upper reaches of the economically important Great Fish River with the aim of determining if diatoms could be used for biomonitoring in semi-arid conditions in southern Africa. Five sites were monitored monthly from 2010 to 2012. Of the 269 diatom taxa belonging to 51 genera identified, the dominant taxa were mostly those considered to be pollution-tolerant: Amphora pediculus, Craticula buderi, Fragilaria biceps, Nitzschia frustulum, Nitzschia paleacea, Planothidium lanceolatum and Rhopalodia gibba. A number of diatombased numerical indices were used to infer water quality, including the generic diatom index, the specific pollution sensitivity index, the biological diatom index, and percentage pollution-tolerant valves, which forms part of the UK trophic diatom index. All index scores showed the Great Fish River to be impacted, and showed significant correlations of diatom species abundance with pH, NO3-N, electrical conductivity, NH4-N and CaCO3. Analysis revealed EC and NO3-N as the main environmental drivers affecting diatom commnity composition, followed by pH and PO4-P. The percentage of diatom deformities at all sites was high, at 3.5%. Diatom indices showed the river to be impacted by decades of agricultural activity, which was confirmed by chemical water analysis. Thus diatom indices can be used for biomonitoring in semi-arid areas.Keywords: agricultural impacts, aquatic ecosystem, biomonitoring, deformed valves, epilithic diatoms, freshwater, Karoo

SUMMARY The terrestrial diatom Microcostatus schoemanii sp. nov. is described from dry soils of the Faan Meintjies Nature Reserve (North-West Province, South Africa). Microcostatus cholnokyi sp. nov. and Microcostatus angloensis sp. nov. are described from sandy soils at a colliery near the town of Kriel (Mpumalanga Province, South Africa). The morphology of these taxa is examined using both light and scanning electron microscopy and new taxa are compared with similar species. In M. schoemanii the density of the striae combined with the valve outline and the distance between the central raphe endings are the main distinguishing morphological features. M. cholnokyi is differentiated by the presence of a conopeum and the distinct structure of the microcostae. M. angloensis is similar to M. schoemanii but differentiated by the shape of the cell and the apices, the angle of striation and the distance in between the proximal raphe endings.

Abdominal and groin injuries are common problems encountered by athletes across a wide variety of sports. They range from benign but annoying, such as exercise-related transient abdominal pain (ETAP), to the activity-limiting and possibly career-ending condition of athletic hernia. This article covers ETAP, rectus abdominus injuries, osteitis pubis, athletic hernia, and abdominal/groin hernias to provide an update on the current pathophysiology and treatment of common abdominal and pelvic conditions in the athlete.

The inclusion of diatoms into the current suite of biomonitoring tools in use in South Africa, as well as the use of European and other diatom indices in South Africa, and in particular the Crocodile and West Marico water management area, is discussed. The indices, when compared to chemical analyses, proved useful in providing an indication of the quality of the investigated waters. Several widely distributed diatom species were shown to have similar ecological tolerances in South Africa when compared to Europe. Although most of the diatoms encountered in the study were cosmopolitan, several possibly endemic species were recorded. The occurrence of endemic species, not included in existing diatom indices may lead to miscalculations of diatom indices. It is concluded that although diatom indices developed in Europe and elsewhere are useful at the present to indicate water quality, a diatom index unique to South Africa including endemic species will have to be formulated.

Two little-known diatom taxa have been encountered in the saprobic and anthropogenically impacted waters of the Vaal River, South Africa. Eolimna archibaldii, an extremely small-celled species, is described as new to science. Navicula adamantiformis Archibald is transferred to the taxonomically-appropriate genus Navigiolum Lange-Bertalot, Cavacini, Tagliaventi and Alfinto, as no specific characters of N. adamantiformis coincide with Navicula sensu stricto.

Diatoms have become important organisms for monitoring freshwaters and their value has been recognised for cross-border water quality monitoring in the European Union. If South Africa is to include diatoms in the current suite of bioindicators, then thorough testing of diatom-based techniques is required. This paper provides guidance on methods through all stages of diatom collection, preparation and examination for the purposes of water quality assessment.African Journal of Aquatic Science 2005, 30(1): 65–75

Historical diatom records provide a means of retrospectively determining water quality and inferring ecological condition in rivers and streams. In this study we re-sampled sites originally sampled 48 years previously. We then determined the scores for the Biological Diatom Index (BDI) and the South African Diatom Index (SADI) for each dataset. The results revealed that the present day conditions in this relatively undisturbed locality were almost identical to those reflected by the samples collected half a century before. This illustrates the value of historical diatom data for the purposes of determining antecedent water quality. Keywords : diatoms, water quality, South Africa, Biological Diatom Index, South African Diatom Index

Diploneis fenestrata, a new aerophilic diatom is described from Lumangwe falls, Zambia. This novel species occurs as an epiphyte on the roots and stems of trees located within the spray zone of the falls. Its morphology was examined with both light and scanning electron microscopy. Diploneis fenestrata is distinguished from other taxa in the genus Diploneis by its prominent square openings ranging in number from 4-14 occurring within the area of the longitudinal canal only at the outer cell wall. The occurrence of these characteristic square openings found in the genus Diploneis is further discussed.

The elbow is a complex joint designed to withstand a wide range of dynamic exertional forces. The location and quality of elbow pain can generally localize the injury to one of the four anatomic regions: anterior, medial, lateral, or posterior. The history should include questions about the onset of pain, what the patient was doing when the pain started, and the type and frequency of athletic and occupational activities. Lateral and medial epicondylitis are two of the more common diagnoses and often occur as a result of occupational activities. Patients have pain and tenderness over the affected tendinous insertion that are accentuated with specific movements. If lateral and medial epicondylitis treatments are unsuccessful, ulnar neuropathy and radial tunnel syndrome should be considered. Ulnar collateral ligament injuries occur in athletes participating in sports that involve overhead throwing. Biceps tendinopathy is a relatively common source of pain in the anterior elbow; history often includes repeated elbow flexion with forearm supination and pronation. Olecranon bursitis is a common cause of posterior elbow pain and swelling. It can be septic or aseptic, and is diagnosed based on history, physical examination, and bursal fluid analysis if necessary. Plain radiography is the initial choice for the evaluation of acute injuries and is best for showing bony injuries, soft tissue swelling, and joint effusions. Magnetic resonance imaging is the preferred imaging modality for chronic elbow pain. Musculoskeletal ultrasonography allows for an inexpensive dynamic evaluation of commonly injured structures.

During a survey of the freshwater diatom flora of the Senegal River, an unknown Placoneis species was observed that was initially identified as Placoneis gastrum. Detailed morphological analysis using both light and scanning electron microscopy observations revealed sufficient morphological differences to separate this species as Placoneis cocquytiae sp. nov. The new species is characterized by a rather broadly lanceolate to elliptic-lanceolate valve outline with rostrate, protracted, broadly rounded apices. The central area has an irregular shape due to the shortening of several striae. An isolated pore is lacking. The new species is compared with similar Placoneis and Navicula s.l. taxa and a short biogeographical analysis based on confirmed African records is presented. So far, P. cocquytiae is also present in Zambia and Lake Tanganyika.

The fluorescent, oxazole yellow dye YO-Pro-1 iodide (YO) and its homodimer YOYO-1 iodide (YOYO) were studied in a thrombin-binding DNA ligand, or aptamer, (tb-ligand) and in an oligomer with the same base composition in a scrambled sequence (s-ligand), both single strands of 15 bases in length. Binding constants for the dye-ligand complexes, assuming 1:1 stoichiometry, were determined to be on the order of 107M−1 for YOYO and 105M−1 for YO, which are approximately 105 smaller than estimated constants for YOYO in double-stranded DNA. In both ligands, YOYO assumes a folded conformation that promotes stability of the dye-ligand complex and excitonic coupling between the two YO groups. The folded conformation provides greater overlap of the YO groups than has been reported for YOYO in double-stranded DNA; the overlap is slightly greater in tb-ligand than in s-ligand. Both dyes exhibit bi-exponential fluorescence decay in the ligands and the lifetimes of YOYO (3–4 ns and 7–8 ns) are longer and more discrete than those of YO (1–3 ns and 4–5 ns). Fluorescence anisotropy of YOYO is a low, constant value in both ligands due to intramolecular energy transfer between the overlapping YO groups. Higher anisotropies are observed for YO, and the value is slightly higher in s-ligand than in tb-ligand. The addition of thrombin to the s-ligand affects the fluorescence intensity and anisotropy of YO but not of YOYO. The absence of intermolecular G-quartet formation of the s-ligand was demonstrated. This suggests that thrombin interacts weakly with the s-ligand but is not sensed by the fluorescence of YOYO, which is dominated by the coupling between the YO groups in the folded conformation of the bound dye. The results of these studies have implications for the application of these dyes for detection of single-stranded DNA ligands and their binding interactions. © 1996 John Wiley & Sons, Inc.

A study was made of the type material of Achnanthidium exiguum (Grunow) Czarnecki. This often encountered and apparently ubiquitous species was originally described as Stauroneis exilis by Kützing from the island of Trinidad and later re–named as Achnanthes exigua by Grunow. The type material for this taxon (Kützing sample 397), housed in the Van Heurck collection at the National Botanic Garden of Belgium, Meise was investigated and the ultrastructure of this taxon was documented using both LM and SEM observations. A new Antarctic taxon, formerly identified as A. exigua, was described as a new species, Achnanthidium australexiguum sp. nov. The position of both taxa within the genus Achnanthidium is briefly discussed.