ghanaopendata/ghanaian-research-english huggingface dataset:
Crustal evolution of alternating Paleoproterozoic belts and basins in the Birimian terrane in southeastern West African Craton

We present a comprehensive review of available geochemical, geochronological and isotopic data on granitoids from the Paleoproterozoic Birimian terrane of Ghana, aimed at providing an in-depth understanding of the geodynamic evolution of southeastern West African Craton. The focus is on plutonic magmatism, crustal recy cling and tectonic setting of the granitoids. The granitoids are mainly TTG suites, calc-alkaline granites, diorites, monzonites, two-mica granites and leucogranites. They are characterized by enrichments in LILE and LREE relative to HREE and HFSE. Their variable positive and negative Eu and Sr anomalies and depletions in Nb-Ta and Ti suggest the presence of residual minerals like hornblende and Fe-Ti oxides (e.g., rutile and ilmenite). The plutons probably formed by partial melting of hydrous basaltic/mafic crust metasomatized by slab-derived melts at different depths. The εHf (− 14.5 to +7.6) and εNd (− 5.3 to +3.5) values and Nd model ages (2.21–2.53 Ga) indicate their crystallization from juvenile magmas derived from a depleted mantle with significant recycling of older crustal material. The older (≥2200 Ma) and younger (<2100 Ma) ages recorded in both belt- and basin type granitoids indicate that magmatism in both types was contemporaneous. Nonetheless, the basins recorded younger peak emplacement ages compared to adjacent belts. The presence of inherited older zircon grains (Archean zircon cores?), is widespread in southeastern WAC. The granitoids formed in a continental arc setting via subduction–accretion processes. Furthermore, the magmatic time-span is more prolonged in southern Ghana, with the sedimentary basins recording the longest intervals of magma emplacement. The sub-chondritic εHf data and Hf model ages strongly suggest the existence of Neoarchean to Mesoarchean crustal material in eastern Ghana during the Birimian crust formation. We propose that the subduction-accretion processes during the Paleoproterozoic Eburnean orogeny in the WAC contributed to the formation of the Columbia supercontinent in the Late Paleoproterozoic-Mesoproterozoic.

Source: UG
Crustal-scale transcurrent shearing in the Paleoproterozoic Sefwi-Sunyani-Comoé region, West Africa

The Paleoproterozoic Sefwi-Sunyani-Comoé region that straddles the Ghana-Ivory Coast border in West Africa has been characterised as resulting from a combination of compression and simple shear with leucogranite intrusion either being prior to the compression or synchronous with late shearing. The analysis of regional magnetic datasets combined with field observations allows us to better define the geometry of the major lithostratigraphic packages and their structural contacts in this region. This analysis reveals a series of elongate rounded leucogranite intrusions enveloped by deformed metasediments. Recent finite element modelling of two-phase aggregates has shown that we can analyse the geometry of these systems both in terms of their finite deformation and their mechanical contrast. We interpret the geometries we see in the Sefwi-Sunyani-Comoé region as reflecting the activity of a major crustal deformation zone which was dominated by simple shear. The comparison with our modelling suggests a finite shear strain of approximately 5 gamma, which in turn implies a lateral displacement of 400. km parallel the Sefwi Greenstone Belt, which places Southern Ghana (EoGhana?) near eastern Burkina Faso prior to deformation. Our analysis also suggests that the leucogranites were already acting as more rigid bodies during the shearing, suggesting that their emplacement was predominantly pre-kinematic. © 2012 Elsevier B.V.

Source: UG
Cryogenian-Ediacaran Crustal Growth And Evolution Of The Active Margin Of The Dahomeyide Belt, Ghana

The study presents detailed petrographical, geophysical, structural and geochemical data of the internal nappes zone to establish the deformational history, origin and tectonic setting and constrain the crustal growth and evolution of the active margin of the Dahomeyide belt. Two main lithological units, (i) deformed meta-granitoids (migmatites and gneisses) and (ii) undeformed granitoids dominate the internal nappe zone. Granitoids are generally I-type, metaluminous to weakly peraluminous, low-K tholeiite to high-K calc-alkaline and of tonalite, granodiorite, and granite affinity. The overall trace element patterns of the studied granitoids characterized by the enriched LILE and depleted HFS, with negative peaks of Nb-Ta, Sr, P, and Ti are indications of arc-related magmatism. Structural analysis reveals four deformation phases (D1-D4). D1 represents Northwest-Southeast (NW-SE) Pan African shortening associated with a continent-continent collision, resulting in westward nappe stacking. Progressive NW-SE shortening resulted in D2 and D3 top-to-the-NW dextral and sinistral thrusting events during the Pan-African orogeny. D4 is an extensional event likely associated with the orogenic collapse phase. The gneisses and migmatites, with dominant axial planar foliations point to their formation in a collisional setting or influence by the Pan-African collisional processes. Continental-arc signatures in these rocks imply continental subduction during their protolith formation. The intrusive granitoid and pegmatite are undeformed. meaning late- to post-orogenic emplacement. These findings suggest that the internal nappes zone archived the subduction-collision and post-collisional phase of the Pan-African orogeny and recorded large-scale migmatization and granitoid emplacement due to partial melting of thickened lower crust between the mid-Cryogenian and late Ediacaran.

Source: UG
Cryogenian-Ediacaran Crustal Growth And Evolution Of The Active Margin Of The Dahomeyide Belt, Ghana.

The study presents detailed petrographical, geophysical, structural and geochemical data of the internal nappes zone to establish the deformational history, origin and tectonic setting and constrain the crustal growth and evolution of the active margin of the Dahomeyide belt. Two main lithological units, (i) deformed meta-granitoids (migmatites and gneisses) and (ii) undeformed granitoids, dominate the internal nappes zone. The granitoids are generally I-type, metaluminous to weakly peraluminous, low-K tholeiite to high-K calc-alkaline and of tonalite, granodiorite and granite affinity. The overall trace element patterns of the studied granitoids characterized by the enriched LILE and depleted HFS, with negative peaks of Nb-Ta, Sr, P and Ti, are indications of arc-related magmatism. Structural analysis reveals four deformation phases (D1-D4). D1 represents Northwest-Southeast (NW-SE) Pan African shortening associated with a continent-continent collision, resulting in westward nappe stacking. Progressive NW-SE shortening resulted in D2 and D3 top-to-the-NW dextral and sinistral thrusting events during the Pan-African orogeny. D4 is an extensional event likely associated with the orogenic collapse phase. The gneisses and migmatites, with dominant axial planar foliations, point to their formation in a collisional setting or influence by the Pan-African collisional processes. Continental-arc signatures in these rocks imply continental subduction during their protolith formation. The intrusive granitoid and pegmatite are undeformed, meaning late- to post-orogenic emplacement. These findings suggest that the internal nappes zone archived the subduction-collision and post-collisional phase of the Pan-African orogeny and recorded large-scale migmatization and granitoid emplacement due to partial melting of thickened lower crust between Mid-Cryogenian and late Ediacaran.

Source: UG
Cryptolepine inhibits hepatocellular carcinoma growth through inhibiting interleukin-6/STAT3 signalling

Background: Diverse signalling pathways are involved in carcinogenesis and one of such pathways implicated in many cancers is the interleukin 6/signal transducer and activator of transcription 3 (IL-6/STAT3) signalling pathway. Therefore, inhibition of this pathway is targeted as an anti-cancer intervention. This study aimed to establish the effect of cryptolepine, which is the main bioactive alkaloid in the medicinal plant Cryptolepis sanguinolenta, on the IL-6/STAT3 signalling pathway. Methods: First, the effect of cryptolepine on the IL-6/STAT3 pathway in human hepatoma cells (HepG2 cells) was screened using the Cignal Finder Multi-Pathway Reporter Array. Next, to confirm the effect of cryptolepine on the IL-6/STAT3 signalling pathway, the pathway was activated using 200 ng/mL IL-6 in the presence of 0.5–2 μM cryptolepine. The levels of total STAT3, p-STAT3 and IL-23 were assessed by ELISA. Results: Cryptolepine downregulated 12 signalling pathways including the IL-6/STAT3 signalling pathway and upregulated 17 signalling pathways. Cryptolepine, in the presence of IL-6, decreased the levels of p-STAT3 and IL-23 in a dose-dependent fashion. Conclusion: Our results demonstrated that cryptolepine inhibits the IL-6/STAT3 signalling pathway, and therefore cryptolepine-based remedies such as Cryptolepis sanguinolenta could potentially be used as an effective immunotherapeutic agent for hepatocellular carcinoma and other cancers

Source: UG
Cryptolepine Suppresses Colorectal Cancer Cell Proliferation, Stemness, and Metastatic Processes by Inhibiting WNT/β-Catenin Signaling

Colorectal cancer (CRC) is the third most frequent cancer and the second leading cause of cancer-related deaths globally. Evidence shows that over 90% of CRC cases are initiated by a deregulated Wingless Integrated Type-1 (WNT)/β-catenin signaling pathway. The WNT/β-catenin pathway also promotes CRC cell proliferation, stemness, and metastasis. Therefore, modulators of the WNT/β-catenin pathway may serve as promising regimens for CRC. This study investigated the effect of cryptolepine—a plant-derived compound—on the WNT/β-catenin pathway in CRC. Two CRC cell lines, COLO205 and DLD1, were treated with cryptolepine or XAV 939 (a WNT inhibitor) in the presence or absence of WNT3a (a WNT activator). Using a tetrazolium-based assay, cryptolepine was found to reduce cell viability in a dose- and time-dependent manner and was a more potent inhibitor of viability than XAV 939. RT-qPCR analyses showed that cryptolepine reverses WNT3a induced expression of β-catenin, c-MYC, and WISP1, suggesting that cryptolepine inhibits WNT3a mediated activation of WNT/β-catenin signaling. Cryptolepine also repressed WNT3a-induced OCT4 and CD133 expression and suppressed colony formation of the cells, indicating that cryptolepine inhibits the stemness of CRC cells. Additionally, cryptolepine inhibited WNT3a-induced epithelial-to mesenchymal transition by reducing the expression of SNAI1 and TWIST1 genes. In a wound healing assay, cryptolepine was found to suppress cell migration under unstimulated and WNT3a-stimulated conditions. Moreover, cryptolepine downregulated WNT3a-induced expression of MMP2 and MMP9 genes, which are involved in cancer cell invasion. Altogether, cryptolepine suppresses CRC cell proliferation, stemness, and metastatic properties by inhibiting WNT3a-mediated activation of the WNT/β-catenin signaling pathway. These findings provide a rationale for considering cryptolepine as a potential WNT inhibitor in CRC.

Source: UG
Cryptosporidium oocysts in Ghanaian AIDS patients with diarrhoea.

Background:Although Cryptosporidium spp.infections in acquired immunodeficiency syndrome patients (AIDS) with chronic diarrhoea have been reported in several African countries, there is no information regarding cryptosporidial diarrhoea in Ghanaian AIDS patients. Objective:To investigate the occurrence of C. parvumand other gastrointestinal parasitic agents in Ghanaian AIDS patients with chronic diarrhoea. Design:Prospective study of HIV/AIDS patients with diarrhoea over a nine month period. Setting:Korle-Bu Teaching Hospital and Korle-Bu Polyclinic Accra, Ghana. Results:Analysis of stool specimens from clinically diagnosed HIV/AIDS (n=2I; mean CD4 count was 288 cells per microliter, 95% confidence interval of 237 to 340 cells per microliter) and HIV-seronegative (n=27) patients revealed C. parvumin six (28.6%) of HIV/AIDS and 10 (37.0%) of the HIV-seronegative patients, respectively. Three other HIV/AIDS cases had other infections involving Strongyloides stercoralis 4.8% (l/21) and Salmonella spp . 9.5% (2/21). There was no concomitant association between C. parvumand any other parasites found. Also, no enterobacteria was found in the HIV-seronegative patients. Conclusion:This study demonstrates the prevalence of Cryptosporidiumsp. in both HIV/ AIDS and HIV-seronegative individuals in Ghana. However, there was no statistical association between cryptosporidiosis and HIV/AIDS (p>0.05).

Source: UG
Cryptosporidium Spp., a Frequent Cause of Diarrhea among Children at the Korle-Bu Teaching Hospital, Accra, Ghana

This report presents the results of a study conducted at the Child Health Department, Korle-Bu Teaching Hospital, Accra, Ghana, between the months of October 2001 and June 2002. Stool samples from 227 children with diarrhea and 77 children without diarrhea, aged less than 5 years, were tested for Cryptosporidium spp. Prevalence rates were 27.8 and 15.6% in children with and without diarrhea, respectively. Cryptosporidium infection was found to be high in children between the ages of 6 and 24 months. Cryptosporidium spp. was more common in malnourished children, but was not isolated in children under 6 months of age who were exclusively breastfed. Neither the presence of domestic animals, abdominal pain, blood in stool, nausea, vomiting, nor the consumption of untreated water was associated with Cryptosporidium spp. infection. Shigella, Salmonella, and yeast-like organisms were the most frequently identified enteropathogenic bacteria. In summary, this study demonstrates the prevalence of Cryptosporidium spp. among Ghanaian children.

Source: UG
Crystal structure and in vitro antimicrobial activity studies of Robustic acid and other Alpinumisoflavones isolated from Millettia thonningii

We report a systematic study of the antibacterial inhibitory potential of isoflavone natural products isolated from the seeds extracts of Millettia thonningii. In an effort to gain bond topological information which may have consequences for the observed bioactivities, the crystal structure of robustic acid was solved and refined using the independent atom as well as the invariom model, and the structures were compared. Robustic acid contains a fused tricyclic unit with a benzopyran moiety, with a phenylene ring substitution on the coumarin ring similar to the alpinumisoflavones isolated from this plant. At a minimum inhibitory concentration of ~1 mg/mL, alpinumisoflavone and robustic acid were found to be cytotoxic to Staphylococcus aureus (ATCC 25923) showing a zone of inhibition (ZOI) of ~9 mm. On the other hand, at ~2 mg/mL, these compounds were found to be bacteriostatic to a hospital isolate of Salmonella typhi with about 7 mm ZOI. Taken together, these compounds offer potential new avenues for targeting both Gram positive and negative bacteria and could be useful as chemical probes for understanding these pathogens in an effort to overcome drug resistance.

Source: UG
Crystal structure of 4'-O-methylalpinumisoflavone at 90K

4'-O-Methylalpinumisoflavone crystals which hitherto had been difficult to crystallize for X-ray diffraction analyses have been obtained from a demethylated product of O, O- dimethylalpinumisoflavone. The structural and conformational features of the crystal measured at 90 K are reported and compared with previously reported work of O,O-dimethylalpinumisoflavone and 5-O-methyl-4'-O-(3-methyl-but-2-en-1-yl) alpinumiso-flavone. Each of these compounds is characterized by a six membered ring that is further fused to a benzopyrone isoflavone moiety resulting in a tricyclic ring system. This six membered ring shows a half-chair conformation in all the molecules studied, with the ring in the title compound showing the least Cremer-Pople puckering amplitude Q and shorter inter and intramolecular contacts. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA,.

Source: UG
Crystal Structure of a Retroviral Polyprotein: Prototype Foamy Virus Protease-Reverse Transcriptase (PR-RT)

In most cases, proteolytic processing of the retroviral Pol portion of the Gag-Pol polyprotein precursor produces protease (PR), reverse transcriptase (RT), and integrase (IN). However, foamy viruses (FVs) express Pol separately from Gag and, when Pol is processed, only the IN domain is released. Here, we report a 2.9 Å resolution crystal structure of the mature PR-RT from prototype FV (PFV) that can carry out both proteolytic processing and reverse transcription but is in a configuration not competent for proteolytic or polymerase activity. PFV PR-RT is monomeric and the architecture of PFV PR is similar to one of the subunits of HIV-1 PR, which is a dimer. There is a C-terminal extension of PFV PR (101-145) that consists of two helices which are adjacent to the base of the RT palm subdomain, and anchors PR to RT. The polymerase domain of PFV RT consists of fingers, palm, thumb, and connection subdomains whose spatial arrangements are similar to the p51 subunit of HIV-1 RT. The RNase H and polymerase domains of PFV RT are connected by flexible linkers. Significant spatial and conformational (sub)domain rearrangements are therefore required for nucleic acid binding. The structure of PFV PR-RT provides insights into the conformational maturation of retroviral Pol polyproteins.

Source: UG
The crystal structures of O,O-Dimethylalpinumisoflavone and 5-O-Methyl-4′-O-(3-methyl-but-2-en-1-yl)alpinumisoflavone

The petrol extract of the rootbark of Milletia Thonningii obtained by column chromatography afforded sixteen different crystalline samples to be isolated. The crystal structures of two of these compounds, O,O-Dimethylalpinumisoflavone (I) and 5-O-Methyl-4′-O-(3-methyl-but-2-en-1-yl)alpinumisoflavone (II) are being reported here. (II) has two independent molecules in the asymmetric unit and differs from (I) in a longer side chain attached to C(15) of the phenyl ring. The structural features of the three molecules in the title compounds are reported and compared. The derivatives, being subject of this article are the first reported crystal structures where the isoflavone fragment is fused to a further six membered ring that results in a tricyclic ring system. The benzopyrone fragments are planar. The dihedral angles between the benzopyrone fragment and the phenyl ring being 55.38(6)° for (I) and 44.75(15)°/44.64(15)° for the respective independent molecules of (II) are within the range of values observed for similar structures.

Source: UG
Crystallization of linde type a nanomaterials at two temperatures exhibit differential inhibition of HeLa cervical cancer cells in vitro

This work reports evidence of the synthesis of zeolite A at two different temperatures (60 °C and 105 °C) from kaolin. XRD spectral analysis revealed percent crystallinity of 74 ± 2 and 71 ± 3 in LTA60 and LTA105 respectively. The average crystallize size of LTA60 and LTA105 was also estimated using Scherrer's equation to be 57 nm. FTIR analysis showed signature peaks characteristics of zeolite A in the two materials, except the appearance of absorbance peak at 2380 cm-1 in the LTA60 spectrum which was not observed in LTA105. Nitrogen porosity measurements of LTA60 and LTA105 gave the following parameters: average pore width of 2.45 and 1.01 nm respectively for LTA60 and LTA105, surface areas of 19.18 and 8.00 m2/g and pore volume of 0.012 and 0.002 cm3/g in that order. The influence of the materials on HeLa cancer cell growth was also investigated and the results showed differential inhibitory effects with LTA60 revealing pronounced inhibitory effects compared to LTA105 after 72 hours of cell incubation. This studies highlighted the importance of crystallization conditions that could influence the physicochemical parameters including structure, porosity, size, and morphology of zeolite materials on cell activity. The work also provided unique opportunities for utilizing natural deposits of kaolin globally to fabricate biomimetic materials for various biological applications. © 2016 Trans Tech Publications, Switzerland.

Source: UG
“CSR-OHS: Expert Views, Analysis and Commentary on the two potent contrivances towards achieving MDGs”

Purpose – The purpose of this paper is to trace the path to achieving the millennium development goals (MDG) in developing countries through the lens of corporate social responsibility (CSR) and organisation health and safety (OHS). Design/methodology/approach – The paper employed discourse analysis of views of participants of the workshop on CSR-OHS project in Accra, funded by the British Council's Development Partnership in Higher Education (DelPHE). The analysis was shaped by the various theorizations and conceptualisations of CSR and OHS in developed and developing countries, in order to establish any link between CSR-OHS and the MDG. Findings – The paper established some linkage between CSR, OHS and the MDG. Although the paper observed divergence in practice between the two concepts of CSR and OHS, Ghanaians viewed OHS as a key competing dimension of CSR. Problem areas were identified with respect to OHS implementation and regulations and standardization proposed for its improvement. The paper calls for the provision of effective and efficient OHS services and the introduction of OHS courses in the curricula of higher educational institutions as a national strategy. Originality/value – The paper demonstrates the relevance of OHS in the CSR concept as a tool for achieving the MDGs.

Source: UG
Cuff Inflation to Aid Nasotracheal Intubation Using the C-MAC Videolaryngoscope

A preliminary report is presented of a technique for using the C-MAC videolaryngoscope to carry out nasopharyngeal intubations. The main thrust of the technique is that cuff inflation of the endotracheal tube is used to lift the endotracheal tube off the posterior pharyngeal wall and thus direct it towards the glottis. The technique was used successfully in 5 consecutive patients needing nasotracheal intubation. Indeed a couple of these patients might have been difficult to intubate using conventional laryngoscopy. The full technique is described together with pictures at the various stages of intubation.

Source: UG
The Cult of the Kwahu Hunter on the Question of Sasa Animals, Especially the Elephant

Since Capt. Rattray came to Kwahu, he has discovered that the people there are an off-shoot of the Beretuo Clan, and that they came from Ashanti Mampon and settled in their present district about 200 years ago. When Capt. Rattray told me tills, it explained to me the remarkable parallel, as well as the differences, between the hunting customs noted by him in Ashanti, and those observed in Kwahu ; a parallel that had hitherto seemed to me quite inexplicable.

Source: UG