158 research outputs found

    On Sensor-Based Ore Sorting

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    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

    Design of an Integrated Anti-Hardening System for Carbon-In-Leach Tanks

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    Slurry density monitoring is of paramount importance in the industrial world. Most industries, especially cement and mineral processing industries, employ this method to obtain good quality products. However, most Carbon-In-Leach (CIL) tanks of gold processing industries do not use slurry density monitoring systems. As a result, many a time, agitation difficulties occur when the slurry begins to harden. This paper, therefore, seeks to design an integrated anti-hardening system for CIL tanks, with the aid of a microcontroller, to monitor the density of the slurry in order to prevent it from hardening. Slurry density measurement was achieved with the help of a strain gauge pressure sensor and a couple of level sensors. Atmega 328p  microcontroller board was programmed to continuously compute the density of the slurry from values of pressure and level of slurry in the tank indicated by the pressure and level sensors, respectively. The microcontroller responds to slurry hardening by activating a light emitting diode and triggering the piezo buzzer when a set point is reached. The designed circuit was successfully simulated using Proteus 8.2 design suite software to ascertain its functionality. Based on the results obtained, the light emitting diode and piezo buzzer activated when the set point was reached. It was concluded that the anti-hardening system is effective for constantly monitoring the density of the slurry to prevent it from hardening. It was also recommended that the mining industries could employ the designed system to monitor the density in order to prevent hardening of slurry in CIL tanks. Keywords: Carbon-In-Leach Tanks, Slurry Densisty, Strain Guage Pressure Sensor, Microcontrolle

    Diagnostic performance of endoscopic ultrasound-guided tissue acquisition of splenic lesions: systematic review with pooled analysis

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    Background: Focal splenic lesions are usually incidentally discovered on radiological assessments. Although percutaneous tissue acquisition (TA) under trans-abdominal ultrasound guidance is a well-established technique for obtaining cyto-histological diagnosis of focal splenic lesions, endoscopic ultrasound (EUS)-guided TA has been described in several studies, reporting different safety and outcomes. The aim was to assess the pooled safety, adequacy, and accuracy of EUS-TA of splenic lesions. Methods: A comprehensive review of available evidence was conducted at the end of November 2021. All studies including more than five patients and reporting about the safety, adequacy, and accuracy of EUS-TA of the spleen were included. Results: Six studies (62 patients) were identified; all studies have been conducted using fine-needle aspiration (FNA) needles. Pooled specimen adequacy and accuracy of EUS-TA for spleen characterization were 92.8% [95% confidence interval (CI), 86.3%-99.3%] and 88.2% (95% CI, 79.3%-97.1%), respectively. The pooled incidence of adverse events (six studies, 62 patients) was 4.7% (95% CI, 0.4%-9.7%). Conclusion: EUS-FNA of the spleen is a safe technique with high diagnostic adequacy and accuracy. The EUS-guided approach could be considered a valid alternative to the percutaneous approach for spleen TA

    Trends and risk factors associated with stillbirths: a case study of the Navrongo War Memorial Hospital in Northern Ghana

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    Maternal and Child health remains at the core of global health priorities transcending the Millennium Development Goals into the current era of Sustainable Development Goals. Most low and middle-income countries including Ghana are yet to achieve the required levels of reduction in child and maternal mortality. This paper analysed the trends and the associated risk factors of stillbirths in a district hospital located in an impoverished and remote region of Ghana.; Retrospective hospital maternal records on all deliveries conducted in the Navrongo War Memorial hospital from 2003-2013 were retrieved and analysed. Descriptive and inferential statistics were used to summarise trends in stillbirths while the generalized linear estimation logistic regression is used to determine socio-demographic, maternal and neonatal factors associated with stillbirths.; A total of 16,670 deliveries were analysed over the study period. Stillbirth rate was 3.4% of all births. There was an overall decline in stillbirth rate over the study period as stillbirths declined from 4.2% in 2003 to 2.1% in 2013. Female neonates were less likely to be stillborn (Adjusted Odds ratio = 0.62 and 95%CI [0.46, 0.84]; p = 0.002) compared to male neonates; neonates with low birth weight (4.02 [2.92, 5.53]) and extreme low birth weight (18.9 [10.9, 32.4]) were at a higher risk of still birth (p<0.001). Mothers who had undergone Female Genital Mutilation had 47% (1.47 [1.04, 2.09]) increase odds of having a stillbirth compared to non FGM mothers (p = 0.031). Mothers giving birth for the first time also had a 40% increase odds of having a stillbirth compared to those who had more than one previous births (p = 0.037).; Despite the modest reduction in stillbirth rates over the study period, it is evident from the results that stillbirth rate is still relatively high. Primiparous women and preterm deliveries leading to low birth weight are identified factors that result in increased stillbirths. Efforts aimed at impacting on stillbirths should include the elimination of outmoded cultural practices such as FGM

    Impact of biliary stents on the diagnostic accuracy of EUS-guided fine-needle biopsy of solid pancreatic head lesions: A multicenter study

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    There is no clear evidence of a negative impact of biliary stents on the diagnostic yield of EUS-guided fine-needle biopsy (EUS-FNB) for diagnosing pancreatic head lesions. We aimed to evaluate the association between the presence of biliary stents and the diagnostic accuracy of EUS-FNB. Materials and Methods: A multicenter retrospective study including all jaundiced patients secondary to pancreatic head masses was performed. Patients were divided into two groups according to the presence of a biliary stent placed before EUS-FNB. Pathological results were classified according to the Papanicolaou classification and compared against the final diagnosis. Diagnostic measures in the two groups were compared. Multivariate logistic regression analyses including potential factors affecting EUS-FNB accuracy were performed. Results: Overall, 842 patients were included, 495 (58.8%) without and 347 (41.2%) with biliary stent. A plastic or a metal stent was placed in 217 (62.5%) and 130 (37.5%) cases, respectively. Diagnostic sensitivity and accuracy were significantly higher in patients without biliary stent than in those with stent (91.9% and 92.1% vs. 85.9% and 86.4%, P = 0.010 At multivariate analyses, lesion size (odds ratio [OR]: 1.05, 95% confidence interval [CI]: 1.02-1.09, P = 0.01) and presence of biliary stent (OR: 0.51, 95% CI: 0.32-0.89, P = 0.01) were independently associated with diagnostic accuracy. In the subgroup of patients with biliary stent, the type of stent (plastic vs. metal) did not impact EUS-FNB yield, whereas the use of larger bore needles enhanced diagnostic accuracy (OR: 2.29, 95% CI: 1.28-4.12, P = 0.005). Conclusions: In this large retrospective study, an indwelling biliary stent negatively impacted the diagnostic accuracy of EUS-FNB. Preferably, EUS-FNB should precede endoscopic retrograde cholangiopancreatography, especially in the case of small tumors

    Relationship between Plasmodium falciparum malaria prevalence, genetic diversity and endemic Burkitt lymphoma in Malawi

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    Endemic Burkitt lymphoma (eBL) has been linked to Plasmodium falciparum (Pf) malaria infection, but the contribution of infection with multiple Pf genotypes is uncertain. We studied 303 eBL (cases) and 274 non eBL-related cancers (controls) in Malawi using a sensitive and specific molecular-barcode array of 24 independently segregating Pf single nucleotide polymorphisms. Cases had a higher Pf malaria prevalence than controls (64.7% versus 45.3%; odds ratio [OR] 2.1, 95% confidence interval (CI): 1.5 to 3.1). Cases and controls were similar in terms of Pf density (4.9 versus 4.5 log copies, p = 0.28) and having ≥3 non-clonal calls (OR 2.7, 95% CI: 0.7-9.9, P = 0.14). However, cases were more likely to have a higher Pf genetic diversity score (153.9 versus 133.1, p = 0.036), which measures a combination of clonal and non-clonal calls, than controls. Further work is needed to evaluate the possible role of Pf genetic diversity in the pathogenesis of endemic BL

    Bringing the Street Back In:Considering Strategy, Contingency and Relative Good Fortune in Street Children’s Access to Paid Work in Accra

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    A sociology of street children has emerged defined by its rejection of the dominant narratives of child welfare organisations that identify the street as the root cause of children’s immiseration and improper socialisation. In its place, sociological analysis has undermined the value of conceptualising street children as a coherent group on the street and in a parallel move has looked to conceptually reposition street children away from assumptions of passivity and neglect, towards a foundational insistence that the starting place for analysis is the positioning of street children as active and strategic social agents. It is the adequacy of this latter concern that is the focus of this article. By reintroducing the location of children within the social relations of the informal street economy, this article draws upon extensive and long-term qualitative research examining the lives of street children in Accra, Ghana. The argument here is that sociological notions of strategic action and efficacious agency seem ill-suited to accounting for the dilemmas and difficulties that street children’s quests for paid work inevitably involve. Rather, it is relative good fortune within the radical uncertainty of the social relations of the informal street economy that seems much more appropriate to accounting for how these children are integrated into wor

    Impact of RTS,S/AS02A and RTS,S/AS01B on Genotypes of P. falciparum in Adults Participating in a Malaria Vaccine Clinical Trial

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    Objective:RTS,S, a candidate vaccine for malaria, is a recombinant protein expressed in yeast containing part of the circumsporozoite protein (CSP) sequence of 3D7 strain of Plasmodium falciparum linked to the hepatitis B surface antigen in a hybrid protein. The RTS,S antigen is formulated with GSK Biologicals\u27 proprietary Adjuvant Systems AS02A or AS01B. A recent trial of the RTS,S/AS02A and RTS,S/AS01B vaccines evaluated safety, immunogenicity and impact on the development of parasitemia of the two formulations. Parasite isolates from this study were used to determine the molecular impact of RTS,S/AS02A and RTS,S/AS01B on the multiplicity of infection (MOI) and the csp allelic characteristics of subsequent parasitemias.Design:The distribution of csp sequences and the MOI of the infecting strains were examined at baseline and in break-through infections from vaccinated individuals and from those receiving a non-malarial vaccine.Setting:The study was conducted in Kombewa District, western Kenya.Participants:Semi-immune adults from the three study arms provided isolates at baseline and during break-through infections.Outcome:Parasite isolates used for determining MOI and divergence of csp T cell&ndash;epitopes were 191 at baseline and 87 from break-through infections.Results:Grouping recipients of RTS,S/AS01A and RTS,S/AS02B together, vaccine recipients identified as parasite-positive by microscopy contained significantly fewer parasite genotypes than recipients of the rabies vaccine comparator (median in pooled RTS,S groups: 3 versus 4 in controls, P = 0.0313). When analyzed separately, parasitaemic individuals in the RTS,S/AS01B group, but not the RTS,S/AS02A group, were found to have significantly fewer genotypes than the comparator group. Two individual amino acids found in the vaccine construct (Q339 in Th2R and D371 in Th3R) were observed to differ in incidence between vaccine and comparator groups but in different directions; parasites harboring Q339 were less common among pooled RTS,S/AS vaccine recipients than among recipients of rabies vaccine, whereas parasites with D371 were more common among the RTS,S/AS groups.Conclusions:It is concluded that both RTS,S/AS vaccines reduce multiplicity of infection. Our results do not support the hypothesis that RTS,S/AS vaccines elicit preferential effects against pfcsp alleles with sequence similarity to the 3D7 pfcsp sequence employed in the vaccine construct
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