Classifying moisture sources associated with snowfall in the mountains of Lesotho

An average of eight snowfall events occur each year in the eastern Lesotho Highlands.These snowfall events are typically associated with cut-off low(CoLs)systems and mid-latitude cyclones.However,the moisture sources of the snowfall are unclassified and unclear.The Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model,an air mass back trajectory model,has been used to evaluate moisture source waters locally in southern Africa and internationally in China and Europe.This study uses HYSPLIT to determine the source moisture of snow in Lesotho.A list of all 82 snowfall events in Lesotho spanning 2017 to 2022 was compiled using the Snow Report SA Instagram page,including the date and location of snowfall.A 72-hour back trajectory for each snowfall event was initiated for both Afriski and the whole of Lesotho.This amounts to models of moisture source trajectories for 28 and 82 snowfall days,respectively.These air mass pathways are classified according to their frequency per snowfall event,per month in the snow season,per year and for the full period.From this,associated moisture source regions and dominant air mass trajectories were identified.This study reports that the air mass trajectories associated with Afriski and Lesotho as a whole are very similar.The most common pathway of air mass trajectories transporting snow-bearing moisture to Lesotho was an inland trajectory from the northern regions of southern Africa.This pathway makes up 16.6%of all trajectories reported and is associated with the Angola Low,the Congo Air Boundary and the St.Helena High Pressure.

Characterization of six tumorsuppressor genes and microsatellite instability in hepatocellular carcinomain southern African blacks

AIM To analyse cumulative loss of heterozygosity (LOH) of chromosomal regions and tumor suppressor genes in hepatocellular carcinomas (HCCs) from 20 southern African blacks. METHODS p53, RB1, BRCA1, BRCA2, WT1 and E cadherin genes were analysed for LOH, and p53 gene was also analysed for the codon 249 mutation, in tumor and adjacent non tumorous liver tissues using molecular techniques and 10 polymorphic microsatellite markers. RESULTS p53 codon 249 mutation was found in 25% of the subjects, as was expected, because many patients were from Mozambique, a country with high aflatoxin B 1 exposure. LOH was found at the RB1, BRCA2 and WT1 loci in 20%(4/*!20) of the HCCs, supporting a possible role of these genes in HCC. No LOH was evident in any of the remaining genes. Reports of mutations of p53 and RB1 genes in combination, described in other populations, were not confirmed in this study. Change in microsatellite repeat number was noted at 9/*!10 microsatellite loci in different HCCs, and changes at two or more loci were detected in 15%(3/*!20) of subjects. CONCLUSION We propose that microsatellite/genomic instability may play a role in the pathogenesis of a subset of HCCs in black Africans.

Harnessing the RNA interference pathway to advance treatment and prevention of hepatocellular carcinoma

Primary liver cancer is the fifth most common malignan- cy in the world and is a leading cause of cancer-related mortality.Available treatment for hepatocellular carcino- ma(HCC),the commonest primary liver cancer,is rarely curative and there is a need to develop therapy that is more effective.Specific and powerful gene silencing that can be achieved by activating RNA interference(RNAi) has generated enthusiasm for exploiting this pathway for HCC therapy.Many studies have been carried out with the aim of silencing HCC-related cellular oncogenes or the hepatocarcinogenic hepatitis B virus(HBV)and hepatitis C virus(HCV).Proof of principle studies have demonstrated promising results,and an early clinical trial assessing RNAi-based HBV therapy is currently in progress.Although the data augur well,there are several significant hurdles that need to be overcome before the goal of RNAi-based therapy for HCC is realized.Particu- larly important are the efficient and safe delivery of RNAi effecters to target malignant tissue and the limitation of unintended harmful non-specific effects.

An assessment of the climatic suitability of Afriski Mountain Resort for outdoor tourism using the Tourism Climate Index(TCI)

Tourism Climatic Indices(TCIs)are widely used in the global North to quantify the climatic suitability of a destination for tourism.Only one such study has been conducted in southern Africa to date.It is in a chronic shortage of research on tourism and climate change in the southern hemisphere.This study presents the application of the TCI in Lesotho,calculated for the eastern Lesotho Highlands.The region has an emerging tourism sector,which primarily comprises outdoor activities.These include hiking,horse-riding,music festivals,mountain biking,cultural visits,sightseeing,and at the Afriski lodge,skiing and snowboarding.These activities are reliant on climatic conditions that are conducive to the activity taking place,prolonged periods outdoors,and tourist satisfaction of the activity.Climate is a major determinant of both the length of season for these activities and the timing of peak tourist arrivals.Rising temperatures and changes in relative humidity and precipitation pose real threats to hiking,sightseeing and snow tourism at Afriski.The reliance of tourism in the region on specific climatic conditions for successful tourism prompted the use of the TCI.TCI results classify the eastern Lesotho Highlands as having‘good'climatic conditions with an overall TCI score of 64 for the period 2012-2017.Monthly TCI scores for the eastern Lesotho reveal a bimodal-shoulder,meaning the peak climatic conditions are in the regional summer months(December to February).This conflicts with the peak tourist seasons of summer and winter,which align with South African school holidays,and the timing of the most profitable tourism activity(skiing)which occurs during the winter months of June,July and August.Lesotho is landlocked by South Africa.TCI analysis for South Africa reveals more suitable climatic conditions for tourism than Lesotho,with significantly higher scores of 80-89.

Mining seismicity in the Witwatersrand Basin:monitoring,mechanisms and mitigation strategies in perspective

The Kaapvaal Craton in South Africa hosts one of the largest gold placer deposits in the world. Mining in the Witwatersrand Basin here has been the source of about one third to one half of the gold ever produced in the world. Gold was discovered in the Johannesburg area in 1886 and after 120 years of continuous operation, mining is currently approaching depths of 4 000 m. In spite of the challenges and risks that the industry has had to deal with including rock temperature, ventilation and water, one of the most feared hazards in the basin has been the threat from the ongoing occurrence of seismicity and rockbursts. The problem first manifested itself by way of the occurrence of tremors roughly twenty years after the commencement of mining operations. This paper traces the history of the approach to rockbursts and seismicity during the 120 year history of mining in the basin. It portrays a picture of the mining seismicity in terms of monitoring phases, mechanisms and mitigation strategies. The work of research organizations over the years is highlighted with a brief mention of current regulation strategies on the part of the mining inspectorate.

A new apparatus to establish the spontaneous combustion propensity of coals and coal-shales

Coal and coal-shale both tend to undergo spontaneous combustion under favourable atmospheric conditions. The Wits-Ehac index has been developed in South Africa since the late 1980's to test the spontaneous combustion liability of coal. However, in some cases, the Wits-Ehac index fails to produce tangible results when testing coal-shales. To overcome this problem, a new apparatus has been developed to test carbonaceous materials such as coal and coal-shale under chemical reactions with oxygen and an index has been obtained. This index is called the Wits-CT index. The equipment emulates the influence of oxygen adsorption on carbonaceous material for a period of 24 h without a heating system.The Wits-CT index uses the total carbon content of the sample and the temperature variations obtained from the samples during reaction with oxygen to predict the spontaneous combustion liability. Eighteen samples have been analyzed using both indices and the results are in-line. It was found that coals and coal-shales with higher values of the Wits-CT index are more liable to spontaneous combustion.Further research on different coal-shales is underway in order to establish an extensive database for coal and coal-shales, together with known incidences of self-heating.

The role of heredity in pterygium development

Several risk factors,which include heredity,ultra-violet (UV) light and chronic inflammation,contribute to pterygium development.However,there is no report integrating these factors in the pathogenesis of pterygium.The aim of this review is to describe the connection between heredity,UV,and inflammation in pterygium development.Existing reports indicate that sunlight exposure is the main factor in pterygium occurrence by inducing growth factor production or chronic inflammation or DNA damage.Heredity may be a factor.Our studies on factors in pterygium occurrence and recurrence identify that heredity is crucial for pterygium to develop,and that sunlight is only a trigger,and that chronic inflammation promotes pterygium enlargement.We propose that genetic factors may interfere with the control of fibrovascular proliferation while UV light or(sunlight)most likely only triggers pterygium development by inducing growth factors which promote vibrant fibrovascular proliferation in predisposed individuals.It also just triggers inflammation and collagenolysis,which may be promoters of the enlargement of the fibrovascular mass.Pterygium probably occurs in the presence of exuberant collagen production and profuse neovascularisation.

Gold mineralisation and orogenic metamorphism in the Lena province of Siberia as assessed from Chertovo Koryto and Sukhoi Log deposits

The Chertovo Koryto gold deposit（80 t Au at 1.84 g/t） in the Lena world-class province,Siberia,is hosted in a metamorphosed sequence of the Paleoproterozoic Mikhailovsk Formation that comprises the oldest black shale strata of the Baikal-Patom region.The mineralisation is confined to the thrust zone complicated with a conjugate anticline fold,zones of shearing and dislocation.The struaural position of the mineralisation is similar to that at the giant Sukhoi Log deposit in the neighbouring Mama-Bodaibo zone.In the latter,the isotope age data suggest that Khomolkho black shales,hosts to Sukhoi Log mineralisation,are of Ediacaran age and underwent prograde metamorphism during early Paleozoic.The geochemical composition of the terrigenous rocks that host Sukhoi Log,Chertovo Koryto,and a number of other deposits at the various stratigraphic levels throughout the Proterozoic sequence have much in common.They do not show elevated metal contents above the common black shale abundances,except for Au and As,which is at variance with the accepted view on diagenetic enrichment of black shales in the Lena province.The occurrence of sagenitic rutile in quartz and chlorite pseudomorphs after biotite and other petrographic observations provide evidence on a retrograde nature of the metamorphic mineral assemblages in the Mikhailovsk rocks.The sulphides are pyrrhotite and arsenopyrite with very minor pyrite at Chertovo Koryto,whereas pyrite is the predominant sulphide in the Sukhoi Log ore.Fluid inclusion data on both deposits emphasise a high-temperature nature of the mineralisation albeit revealing great contrast in the fluid composition.Sukhoi Log mineralisation was formed at mixing between low-salinity aqueous solutions and dense gaseous carbonic fluids,which facilitated effective gold scavenging and precipitation,as demonstrated by thermodynamic simulation.The precursory devolatilisation of the Mikhailovsk sediments at the prograde stage results in the paucity of gaseous carbonic fluid during retrograde metamorphism and mineralisation.The similarity in the styles and chemical parameters of mineralisation,and the predominant structural control of ore localisation within the same Precambrian regional tectonic unit support an idea that orogenic gold mineralisation in the Lena province was produced during a single early Paleozoic event.

Silencing hepatitis B virus covalently closed circular DNA: The potential of an epigenetic therapy approach

Global prophylactic vaccination programmes have helped to curb new hepatitis B virus(HBV)infections.However,it is estimated that nearly 300 million people are chronically infected and have a high risk of developing hepatocellular carcinoma.As such,HBV remains a serious health priority and the development of novel curative therapeutics is urgently needed.Chronic HBV infection has been attributed to the persistence of the covalently closed circular DNA(cccDNA)which establishes itself as a minichromosome in the nucleus of hepatocytes.As the viral transcription intermediate,the cccDNA is responsible for producing new virions and perpetuating infection.HBV is dependent on various host factors for cccDNA formation and the minichromosome is amenable to epigenetic modifications.Two HBV proteins,X(HBx)and core(HBc)promote viral replication by modulating the cccDNA epigenome and regulating host cell responses.This includes viral and host gene expression,chromatin remodeling,DNA methylation,the antiviral immune response,apoptosis,and ubiquitination.Elimination of the cccDNA minichromosome would result in a sterilizing cure;however,this may be difficult to achieve.Epigenetic therapies could permanently silence the cccDNA minichromosome and promote a functional cure.This review explores the cccDNA epigenome,how host and viral factors influence transcription,and the recent epigenetic therapies and epigenome engineering approaches that have been described.

Optimization of drilling and blasting operations in an open pit mine——the SOMAIR experience

Drilling and blasting play vital roles in opencast mining. These operations not only affect the cost of production directly but as well and significantly, the overall operational costs. This research was carried out to find a possible way of optimizing the drilling and blasting operations in an open pit mine of Somair (Société des Mines de l’Air), in the Niger Republic. In order to optimize the drilling operation, the time taken by two drilling machines to accomplish the same task was analyzed statistically. The result indicates that the Down the Hole Hammer Drilling Rig (DMNo406) is more efficient than the Drill Master (DM405). The relative unit consumption of two explosives (Explus and Nitram 9), when used under the same operating conditions, were also considered and the results indicate Explus to be more economical per unit consumption with a range of 0.15 g/t–0.183 g/t, when compared with Nitram 9 with a unit consumption range of 0.19 g/t-0.24 g/t in the study area.

The Gaojiacun Mafic-Ultramafic Complex(Sichuan,SW China):Neoproterozoic Magmatic Activity at the Western Margin of the Yangtze Craton

The Neoproterozoic Gaojiacun intrusive complex （GIC） is composed of one big intrusion （ca. 9 × 7.5 km） and numerous satellite intrusions, emplaced in the low-grade schists of the Neoproterozoic Yanbian Group. The main intrusion is concentrically zoned, with peridotite bodies ＋ leucogabbroids in its core （inner zone） and the sequence： olivine hornblende gabbronorite - porphyric pyroxene hornblende gabbronorite （transitional zone） - pyroxene hornblende gabbronorite ＋ hornblende gabbro ＋ diorite （outer zone）, towards the margins. The satellite intrusions are composed either of a single rock type （peridotite, gabbro, diorite or granite） or of different rock types （peridotite ＋ diorite ＋ granite）. Upper crustal contamination is evidenced by the occurrence of numerous metamorphic enclaves, migmatites and mixed rocks in the outer zone of the main intrusion and in the satellite intrusions. Hornblende （often oikocrystic） is present in all mafic and ultramafic rocks. Cu-Ni （-PGE） deposits occur in several satellite intrusions, hosted in peridotite. The geochemical and mineralogical features of GIC support the presence of a subduction zone at the western edge of the Yangtze Craton. A feederrelated genesis of the satellite intrusions is inferred.

Characterization of coal using electron spin resonance： implications for the formation of inertinite macerals in the Witbank Coalfield, South Africa

Coal contains a significant concentration of free radicals as a result of the coalification process. One of the experimental methods sensitive to the presence of radicals is electron spin resonance （ESR）, and differences in ESR spectra for different macerals may provide insight into coal-forming processes. In this study, ESR data along with the H/C atomic ratio （to infer the aromatic fraction） are used to characterize coal samples with the aim of assessing a fire-origin for dominant inertinite macerals. A medium rank C bituminous Witbank No. 4 Seam Upper coal （the parent） was density- fractionated to create vitrinite-rich and inertinite-rich samples. The parent sample consists of 42 vol% vitrinite and 49 vol% inertinite. The density-fractionated samples comprise of 81 vol% total vitrinite （dominated by collotelinite and collodetrinite）, and 63 vol% total inertinite （dominated by fusinite, semifusinite, and inertodetrinite）. The H/C ratio is 0.74 for the inertinite-rich sample, and 0.85 for the vitrinite-rich counterpart, suggesting the former sample is more aromatic. The ESR spectra obtained for the three samples were found to fit best using a Lorentzian distribution. The fit is noticeably better for the aromatic inertinite-rich sample, for which the spectrum is symmetric. This is attributed to pronounced electron mobility and exchange interactions. The higher radical content of the inertinite-rich and parent samples is attributed to the presence of specific inertinite macerals, namely： fusinite, semifusinite, and inertodetrinite. And, owing to the greater radical content of the inertinite-rich sample, the dominant inertinite macerals are interpreted to have formed through charring of plant matter.

A comparison of two formulations of the fin efficiency for straight fins

A formulation of the fin efficiency based on New- ton＇s law of cooling is compared with a formulation based on a ratio of heat transferred from the fin surface to the sur- rounding fluid to the heat conducted through the base. The first formulation requires that the solution of the nonlinear fin equations for constant heat transfer coefficient and constant thermal conductivity is known, whilst the second formulation of the fin efficiency requires only that a first integral of the model equation is known. This paper shows the first for- mulation of the fin efficiency contains approximation errors as only power series and approximate solutions to the non- linear fin equations have been determined. The second for- mulation of the fin efficiency is exact when the first integrals can be determined.

Translation and piloting of the Chinese Mandarin version of an intensive care-specific pressure injury risk assessment tool(the COMHON Index)

Objective:To translate an intensive care-specific pressure injury risk assessment tool(the COMHON Index)from English into Chinese Mandarin.Methods:A four-step approach to instrument translation was utilised:1)English-Mandarin forward-translation by three independent bilinguists;2)Mandarin-English back-translation by two other inde-pendent bilinguists;3)comparison of forward and back-translations,identification of discrepancies,with required amendments returned to step one;and 4)piloting of the translated instrument.The pilot study was undertaken in a Chinese surgical intensive care unit with a convenience sample of 20 nurses.A five-point ordinal scale(1=very difficult;5=very easy)was used to assess ease-of-use and understanding.Translations were retained where medians4 indicated use and understanding was easy to very easy.Results:Five iterations of steps 1 to 3,and two sets of amendments to the original English instrument,were required to achieve translation consensus prior to pilot testing.Subscale scoring,sum scoring,and risk categorisation were documented in most pilot assessments(≥80%),but three sum scores were incorrectly tallied.The overall tool and all subscales were easy to use and understand(medians≥4),and most assessments(16/20,80%)took5 min to complete.Thus,translations were retained,with minor amendments made to instrument instructions for scoring and risk categorisation.Conclusions:An easy-to-use Chinese Mandarin intensive care-specific pressure injury risk assessment tool has been introduced through cross-cultural translation.However,it requires further testing of interrater reliability and agreement.A rigorous translation and reporting exemplar is presented that provides guidance for future translations.

Variations in stir zone and thermomechanically affected zone of dissimilar friction stir weld of AA5083 and AA6082 alloys

Variations in composition,microhardness(in the thermomechanically affected zone)and texture in the tool domain of the dissimilar friction stir weld of AA5083-O and AA6082-T6alloys were investigated.The contents of the major alloying elements in the weld zones were determined using inductively coupled plasma-atomic emission spectroscopy.It was observed that a slight drop in the content of the alloying elements results from the friction stir welding process with the Mg content being the most affected amongst the major alloying elements in the two alloys.By relating the mass fractions of the major alloying elements in the parent metals of both alloys to those of the stir zone,the relative proportions of the two alloys in the stir zone were estimated with the results showing that at least60%of the materials in the stir zone are from the retreating side of the weld.It was also revealed that the changes in the hardness profile in the thermomechanically affected zone of the retreating side are predominantly influenced by changes in grain size in that domain.Finally,the investigation further revealed that the texture component in the tool shoulder domain is different from the texture component in the tool pin domain.

The dynamics of adult neurogenesis in human hippocampus

The phenomenon of adult neurogenesis is now an accepted occurrence in mammals and also in humans.At least two discrete places house stem cells for generation of neurons in adult brain. These are olfactory system and the hippocampus. In animals, newly generated neurons have been directly or indirectly demonstrated to generate a significant amount of new neurons to have a functional role. However, the data in humans on the extent of this process is still scanty and such as difficult to comprehend its functional role in humans. This paper explores the available data on as extent of adult hippocampal neurogenesis in humans and makes comparison to animal data.

Modelling and experimental investigation of effects of moisture and operating parameters during the adsorption of CO2 onto polyaspartamide

Parametric effect of moisture and influence of operating variables on the adsorption behaviour of polyaspartamide during CO2 capture was investigated in this study using experimental and modelling approach. Individual effects of operating conditions (e.g. pressure, temperature and gas flow rates) as well as the effect of moisture on the adsorption capacity of polyaspartamide were methodically investigated using Dubinin-Raduskevich model. Results from the investigations reveal that the presence of moisture in the flue gas had an incremental effect on the adsorption capacity of polyaspartamide;thereby showcasing the potential of polyaspartamide as a suitable hydrophilic material for CO2 capture in power plants. In addition, pressure, temperature and gas flow rates at 200 kPa, 403 K, and 1.5 mL/s, respectively, sig? nificantly influenced the CO2 adsorption capacity of polyaspartamide. Physisorption and chemisorption both governed the adsorption process while equilibrium studies at different temperatures showed that Langmuir isotherm could adequately describe the adsorption behaviour of the material with best fit with R^2>0.95.

Evaluation of line brattice length in an empty heading to improve air flow rate at the face using CFD

The effectiveness of line brattice(LB) ventilation system depends on the associated system variables.However, the effect of these variables on the air flow rates close to the face of the heading is not extensively studied. In this paper, the effect of the LB length in relation to the LB-wall distance on the air flow rate reaching the face is analysed. Scenarios were developed using four LB lengths, two LB-wall distances and two heading depths. These scenarios were simulated with a validated CFD model. The air flow rates and patterns at various locations inside the heading were analysed. This helped to find the minimum LB-face distance that should be maintained for each LB-wall distance to maximise the air flow rate at the face. The minimum length when used will improve ventilation and reduce energy cost.

Predictions of elemental composition of coal and biomass from their proximate analyses using ANFIS, ANN and MLR

The elemental composition of coal and biomass provides significant parameters used in the design of almost all energy conversion systems and projects.The laboratory tests to determine the elemental composition of coal and biomass is time-consuming and costly.However,limited research has suggested that there is a correlation between parameters obtained from elemental and proximate analyses of these materials.In this study,some predictive models of the elemental composition of coal and biomass using soft computing and regression analyses have been developed.Thirty-one samples including parameters of elemental and proximate analyses were used during the analyses to develop multiple prediction models.Dependent variables for multiple prediction models were selected as carbon,hydrogen,and oxygen.Using volatile matter,fixed carbon,moisture and ash contents as independent variables,three different prediction models were developed for each dependent parameter using ANFIS,ANN,and MLR.In addition,a routine for selecting the best predictive model was suggested in the study.The reliability of the established models was tested by using various prediction performance indices and the models were found to be satisfactory.Therefore,the developed models can be used to determine the elemental composition of coal and biomass for practical purposes.

Genotype E:The neglected genotype of hepatitis B virus

Hepatitis B virus(HBV)(sub)genotypes A1,D3 and E circulate in sub-Saharan Africa,the region with one of the highest incidences of HBV-associated hepatocellular carcinoma globally.Although genotype E was identified more than 20 years ago,and is the most widespread genotype in Africa,it has not been extensively studied.The current knowledge status and gaps in its origin and evolution,natural history of infection,disease progression,response to antiviral therapy and vaccination are discussed.Genotype E is an African genotype,with unique molecular characteristics that is found mainly in Western and Central Africa and rarely outside Africa except in individuals of African descent.The low prevalence of this genotype in the African descendant populations in the New World,phylogeographic analyses,the low genetic diversity and evidence of remnants of genotype E in ancient HBV samples suggests the relatively recent reintroduction into the population.There is scarcity of information on the clinical and virological characteristics of genotype E-infected patients,disease progression and outcomes and efficacy of anti-HBV drugs.Individuals infected with genotype E have been characterised with high hepatitis B e antigen-positivity and high viral load with a lower end of treatment response to interferon-alpha.A minority of genotype E-infected participants have been included in studies in which treatment response was monitored.Of concern is that current guidelines do not consider patients infected with genotype E.Thus,there is an urgent need for further large-scale investigations into genotype E,the neglected genotype of HBV.