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Institution

University of Johannesburg

EducationJohannesburg, South Africa
About: University of Johannesburg is a education organization based out in Johannesburg, South Africa. It is known for research contribution in the topics: Population & Tourism. The organization has 8070 authors who have published 22749 publications receiving 329408 citations. The organization is also known as: UJ.


Papers
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Journal ArticleDOI
TL;DR: It was conclusively proved that AgNPs capped with citrate or PVP exhibited significant antibacterial activities in vivo against Salmonella infection compared to uncapped AgNLP, demonstrating the importance of capping agents and the synthesis method in their use as antimicrobial agents for therapeutic purposes.
Abstract: The emergence of multidrug-resistant bacteria is a global threat for human society. There exist recorded data that silver was used as an antimicrobial agent by the ancient Greeks and Romans during the 8th century. Silver nanoparticles (AgNPs) are of potential interest because of their effective antibacterial and antiviral activities, with minimal cytotoxic effects on the cells. However, very few reports have shown the usage of AgNPs for antibacterial therapy in vivo. In this study, we deciphered the importance of the chosen methods for synthesis and capping of AgNPs for their improved activity in vivo. The interaction of AgNPs with serum albumin has a significant effect on their antibacterial activity. It was observed that uncapped AgNPs exhibited no antibacterial activity in the presence of serum proteins, due to the interaction with bovine serum albumin (BSA), which was confirmed by UV-Vis spectroscopy. However, capped AgNPs [with citrate or poly(vinylpyrrolidone)] exhibited antibacterial properties due to minimized interactions with serum proteins. The damage in the bacterial membrane was assessed by flow cytometry, which also showed that only capped AgNPs exhibited antibacterial properties, even in the presence of BSA. In order to understand the in vivo relevance of the antibacterial activities of different AgNPs, a murine salmonellosis model was used. It was conclusively proved that AgNPs capped with citrate or PVP exhibited significant antibacterial activities in vivo against Salmonella infection compared to uncapped AgNPs. These results clearly demonstrate the importance of capping agents and the synthesis method for AgNPs in their use as antimicrobial agents for therapeutic purposes.

140 citations

Journal ArticleDOI
Morad Aaboud, Alexander Kupco1, Samuel Webb2, Timo Dreyer3  +2969 moreInstitutions (195)
TL;DR: Algorithms used for the reconstruction and identification of electrons in the central region of the ATLAS detector at the Large Hadron Collider (LHC) are presented in this article, these algorithms a...
Abstract: Algorithms used for the reconstruction and identification of electrons in the central region of the ATLAS detector at the Large Hadron Collider (LHC) are presented in this paper; these algorithms a ...

140 citations

Journal ArticleDOI
TL;DR: The Lincang Neogene high-Ge coal deposit in Yunnan, southwestern China, is one of the major coal-hosted Ge deposits in the world as mentioned in this paper, and the coal samples are dominated by huminite-group macerals, all having more than 88.5% total huminite.

140 citations

Journal ArticleDOI
TL;DR: A large database of geophysical, petrological and mineralogical measurements for the ~3000 m Bellevue borehole through the entire Upper Zone (UZ) and about half of the Main Zone (MZ) of the Northern Lobe of the Bushveld Complex, South Africa is presented in this paper.
Abstract: We present a large database of geophysical, petrological and mineralogical measurements for the ~3000 m Bellevue borehole through the entire Upper Zone (UZ) and about half of the Main Zone (MZ) of the Northern Lobe of the Bushveld Complex, South Africa. Magnetic susceptibilty readings were taken every 2 cm (n = 109,360) and densities were measured on average every 1.7 m (n = 2252). Petrographic data and microprobe analyses (n = 14,160) were obtained for plagioclase, mafic silicates, Fe-Ti oxides, amphibole and biotite in 502 samples throughout the entire sequence of layered mafic cumulates. The Bellevue UZ, as marked by the first appearance of cumulus magnetite, is ~1190 m thick (corrected for mean dip of 17.5°), which is less than UZ thicknesses in the Eastern and Western Lobes. A prominent 4 m thick pyroxenite horizon occurs ~390 m below the UZ-MZ boundary, but we show on the basis of mineralogy that this horizon cannot be correlated with the well known Pyroxenite Marker (PM) of the Eastern and Western Bushveld Complex. If the PM is indeed absent in the Northern Lobe, then a substantial portion, perhaps 500 m of the uppermost MZ may be missing; possible causes include non-deposition ( e.g. due to syn-magmatic upwarping or diapirism) or removal (e.g. due to emplacement of UZ magmas). The Bellevue drillcore penetrated only about half of the MZ (total dip-corrected thickness ~1270 m), and the lowermost ~200 m contains unusual olivine-bearing (or troctolitic) horizons that are atypical of MZ rocks elsewhere in the Bushveld Complex. These troctolites have mineral compositions as primitive as those of the upper Critical Zone (CZ), suggesting that they might represent a sliver of CZ rocks dismembered by intrusion of MZ magmas. Alternatively, they may represent an intrusive sill of syn- or post-Bushveld age, or merely a mineralogically unusual horizon in otherwise typical MZ lithologies. Mineral compositions show broad normal fractionation upwards, with plagioclase An78→21, opx (and inverted pigeonite) En 80→26, cpx Mg 86→27, olivine Fo 78→74 (in the lowermost troctolitic horizon) and Fo 59→06 (in the UZ olivine ferrodiorites). There are, however, numerous prominent reversals and discontinuities in mineral compositions, some of which are likely related to magma additions. The extensive dataset of mineral compositions allows the estimation of a new fractionation trend for the Bushveld Complex. On an En-An diagram, the Bushveld trend is shifted toward more An-rich plagioclase at equivalent Mg# of coexisting pyroxenes relative to those for Kiglapait or Skaergaard. This is attributed to the relative paucity in Bushveld of augite, which has a high fractionating power for Ca/Na in evolving liquids. Magnetic susceptibility data clearly reveal the presence of the UZ-MZ boundary. MZ cumulates have susceptibilty values <0.05 SI units, and generally <0.02 SI units. Above the UZ-MZ boundary, susceptibilty varies enormously, from anorthosites (<0.1 SI units) to magnetitites (to almost 5 SI units), and there is excellent correlation between susceptibility and lithology, in many cases to a resolution of <5 to 10 cm. Anorthositic rocks, especially in the MZ, commonly show higher susceptibilty than surrounding polyphase cumulates, due to intercumulus and/or dust-like inclusions of magnetite. Density data reveal surprising cyclicity in the Main Zone on the scale of 50 to 200 m, with progressively increasing density upwards in individual layered units, reflecting gradual increase in modal colour index from 0 to 10% to 50 to 60%. In some cases the upward density increases are correlated with broad reversals in chemical fractionation trends (e.g. upward increases in Mg# of pyroxenes), arguing against simple fractionation. We suggest that such layers may represent blending zones in which dense liquids and/or crystals from new magma additions drain downwards into the existing cumulate pile. MZ cumulates, therefore, may have been constructed by successive, compositionally different magmatic influxes, implying the existence of a sub-Bushveld magmatic staging chamber.

140 citations

Journal ArticleDOI
01 May 2015-Gene
TL;DR: The complex interaction and contributions of the three levels of VDR gene regulation are illuminated to endorse consideration of all three regulatory factors when studying gene regulation.

140 citations


Authors

Showing all 8414 results

NameH-indexPapersCitations
Vinod Kumar Gupta16571383484
Arnold B. Bakker135506103778
Trevor Vickey12887376664
Ketevi Assamagan12893477061
Diego Casadei12373369665
Michael R. Hamblin11789959533
E. Castaneda-Miranda11754556349
Xiaoming Li113193272445
Katharine Leney10845952547
M. Aurousseau10340344230
Mika Sillanpää96101944260
Sahal Yacoob8940825338
Evangelia Demerouti8523649228
Lehana Thabane8599436620
Sahal Yacoob8439935059
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
2023196
2022526
20213,152
20202,933
20192,706
20182,150