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Constructive Evaluation of Definitions in a Dynamic Geometry Context
Govender, Rajendran,de Villiers, Michael 한국수학교육학회 2003 수학교육연구 Vol.7 No.1
This study firstly examine 18 prospective secondary mathematics teachers' understanding of the nature of definitions and the use of the dynamic geometry software sketchpad to not only improve their understanding of definitions, but also their ability to define geometric concepts themselves. Results indicated that the evaluation of definitions by accurate construction and measurement enabled students to achieve a better understanding of necessary and sufficient conditions, as well as the ability to more readily find counter-examples, and to recognize uneconomical definitions, and improve them.
AlanaW. Govender,Michael J. Furlong 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.3
The effects of constant rearing temperatures on the development and survival of Amblypelta nitida, Amblypelta lutescens lutescens (Hemiptera: Coreidae) and their egg parasitoid, Anastatus sp. (Hymenoptera: Eupelmidae), were studied in the laboratory. Amblypelta nitida and A. l. lutescens survival and development were studied at 10, 15, 20, 25, 30 and 35 °C. The development rate of both species increased linearly with increasing temperature but insects only developed to adults at 20, 25 and 30 °C; at these temperatures, mean development times for A. nitidawere 87, 64 and 29 days and for A. l. lutescens theywere 93, 65 and 31 days respectively. No eggs of either species hatched at 10 °C and only A. l. lutescens eggs hatched at 35 °C. At all temperatures atwhich insects developed beyond the first instar, mortality rates were highest in the second instar for both species. Lower developmental threshold temperatures to complete development were 15.9 °C and 17.1 °C for A. nitida and A. l. lutescens respectively; A. nitida required 421 degree-days and A. l. lutescens required 404 degree-days to complete development. Anastatus sp. completed development at all six study temperatures and development times decreased from 54 days at 17.5 °C to 16 days at 30 °C; similarly Anastatus sp. survival increased with increasing temperature. The lower developmental threshold temperature and degree-days required for Anastatus sp. to complete development were 15.0 °C and 234 degree-days respectively. Results are discussed with respect to the different geographical distributions of A. nitida and A. l. lutescens and likely interactions with Anastatus sp.
Nalini Govender,Sapna Ramdin,Rebecca Reddy,Thajasvarie Naicker 대한생식의학회 2021 Clinical and Experimental Reproductive Medicine Vol.48 No.2
Objective: Approximately 30% of preeclamptic pregnancies exhibit abnormal liver function tests. We assessed liver injury-associated enzyme levels and circulating transforming growth factor beta (TGF-β) levels in an arginine vasopressin (AVP)-induced pregnant Sprague-Dawley rat model.Methods: Pregnant and non-pregnant Sprague-Dawley rats (n=24) received AVP (150 ng/hr) subcutaneously via mini-osmotic pumps for 18 days. Blood pressure was measured, urine samples were collected, and all animals were euthanized via isoflurane. Blood was collected to measure circulating levels of TGF-β1-3 isomers and liver injury enzymes in pregnant AVP (PAVP), pregnant saline (PS), non-pregnant AVP (NAVP), and non-pregnant saline (NS) rats. Results: The PAVP group showed significantly higher systolic and diastolic blood pressure than both saline-treated groups. The weight per pup was significantly lower in the AVP-treated group than in the saline group (p<0.05). Circulating TGF-β1-3 isomer levels were significantly higher in the PAVP rats than in the NS rats. However, similar TGF-1 and TGF-3 levels were noted in the PS and PAVP rats, while TGF-2 levels were significantly higher in the PAVP rats. Circulating liver-type arginase-1 and 5'-nucleotidase levels were higher in the PAVP rats than in the saline group. Conclusion: This is the first study to demonstrate higher levels of TGF-β2, arginase, and 5'-nucleotidase activity in PAVP than in PS rats. AVP may cause vasoconstriction and increase peripheral resistance and blood pressure, thereby elevating TGF-β and inducing the preeclampsia-associated inflammatory response. Future studies should explore the mechanisms through which AVP dysregulates liver injury enzymes and TGF-β in pregnant rats.
Kiarii Ephraim Muriithi,Govender Krishna Kuben,Mamo Messai Adenew,Govender Penny Poomani 한국물리학회 2022 Current Applied Physics Vol.40 No.-
Calculations of AgSbTe2 thermoelectric material and 2d CdS/TiS2 and their heterostructures were carried out using Density Functional Theory in Cambridge Serial Total Energy Package code as implemented in Material Studio 2018 software. The work function, thermal transport, electronic and optical properties were calculated. The results revealed that the heterostructures are possible to be achieved with improved properties. The electronic and thermal transport properties were likened with the description of equations derived from Boltzmann transport theory and Mott expressed in the maximum achievable Figure merit. Orbital contributions from the electron movement show valence and conduction band atomic shells.
Opoku Francis,Govender Penny P. 한국물리학회 2022 Current Applied Physics Vol.40 No.-
Recently, fabricating type-II vertical van der Waals (vdWs) heterostructure is a promising material for hydrogen production. The absorption capability, charge density distributions, band alignments and electronic properties of the monolayers and heterostructures are systematically investigated using computational studies. Using ab initio molecular dynamics, binding energy and phonon calculations, the stability of the heterostructures are verified. Both heterostructures are type-II materials, which can increase the separation of charge carriers. Moreover, the charge density difference and the potential drop across the interface of MSe2/BSe creates a high built-in electric field that can prevent the recombination of charge carriers. We found that the visible-light optical properties of both heterostructures are much enhanced with suitable bandgap energy for water splitting. The band alignment suggests that the heterostructures straddle water redox potentials in acid solutions (0 < pH < 7). Our study predicted that MSe2/BSe vdW heterostructures have great potential for photocatalytic hydrogen production.
Chetty, R.,Gill, P.,Govender, D.,Bateman, A.,Chang, H.J.,Deshpande, V.,Driman, D.,Gomez, M.,Greywoode, G.,Jaynes, E.,Lee, C.S.,Locketz, M.,Rowsell, C.,Rullier, A.,Serra, S.,Shepherd, N.,Szentgyorgyi, W. B. Saunders Co ; Centrum Philadelphia 2012 Human pathology Vol.43 No.11
The aim of this study was to ascertain the level of concordance among gastrointestinal pathologists for regression grading in rectal cancers treated with neoadjuvant chemoradiation. Seventeen gastrointestinal pathologists participated using the Mandard, Dworak, and modified rectal cancer regression grading systems to grade 10 representative slides that were selected from 10 cases of rectal cancer treated with long-course neoadjuvant chemoradiation. The slides were scanned with a whole-slide scanner generating dynamic digitized images. The results showed very little concordance across the 3 grading systems, with κ values of 0.28, 0.35, and 0.38 for the Mandard, Dworak, and modified rectal cancer regression grading systems, respectively. In only 1 of 10 study cases was there unanimous grading concordance using the modified rectal cancer regression grading system. It was felt that these systems lacked precision and clarity for reproducible, accurate regression grading. The study concluded that there was a need for a simple, reproducible regression grading system with clear criteria, a cumulative or composite score taking into account all sections of the tumor bed that is sampled rather than the worst section (highest grade), and there should be a uniform method of sampling of these specimens.
Angiotensin I-Converting Enzyme Inhibitor Activity of Nutritive Plants in KwaZulu-Natal
S. Ramesar,H. Baijnath,T. Govender,I. Mackraj 한국식품영양과학회 2008 Journal of medicinal food Vol.11 No.2
Traditional herbal remedies still form an integral part of South African culture, hence necessitating reports onthe scientific rationale for their uses. Organic and aqueous extracts from 16 nutritive plants found in KwaZulu-Natal, SouthAfrica were screened for angiotensin I-converting enzyme (ACE) inhibitory activity using a fluorometric enzyme assay. Aplant was considered to have potential antihypertensive properties if it inhibited the ACE enzyme and thus the conversion ofangiotensin I to angiotensin II by greater than 50%. Eight of the 16 plants screened demonstrated ACE inhibitory activity andsatisfied these criteria. These eight plants were then subjected to a gelatin salt block test for tannins to show that the ACE in-hibitory activities were not due to the presence of tannins, as tannins also inhibit ACE activity. The plants that showed ACEinhibitory activity were Amaranthus dubius, Amaranthus hybridus, Asystasia gangetica, Galinsoga parviflora, Justicia flava,Oxygonum sinuatum, Physalis viscosa, and Tulbaghia violacea. T. violaceain particular shows promise with regards to ACEinhibition as in vivo administration of this extract showed only a 2.2% increase in maximum mean arterial pressure whencompared to the 14.5% increase observed in the control group after co-administration with exogenous Ang I.
Masha Maharaj,Lucille Heslop,Trisha Govender,Nisaar Korowlay,Aviral Singh,Partha Choudhary,Mike Sathekge 대한핵의학회 2021 핵의학 분자영상 Vol.55 No.3
Prostate-specific membrane antigen (PSMA)-directed radioligand therapy (PSMA-RLT) with lutetium-177 (177Lu-PSMA) has been used in metastatic castrate-resistant prostate cancer (mCRPC), and retrospective data have shown this therapy to be favourably safe with attractive clinical responses. Re-challenge 177Lu-PSMA therapy in early responders has been shown to be safe and effective. We report the use of low-dose Taxol-based chemotherapy (modified dose 25 mg/m2 weekly × 6 weeks) as a radiosensitizer with re-challenge 177Lu-PSMA therapy (4 cycles). In a period of 3 years, the patient underwent a total of 8 cycles of 177Lu-PSMA with a cumulative dose of 51.8 GBq. All therapies were uneventful and well tolerated. There was a good response to re-challenge 177Lu-PSMA therapy and low-dose docetaxel (Taxol-177Lu-PSMA) with no recorded tumour resistance.
Ndaba Nokuthula,Fotsing Marthe Carine,Anku William Wilson,Govender Penny Poomani 경희대학교 융합한의과학연구소 2020 Oriental Pharmacy and Experimental Medicine Vol.20 No.3
Drimia delagoensis (D. delagoensis), a member of the Hyacinthaceae family, is commonly used for the treatment of heartwater and skin ailments by the Zulus in South Africa. In this research study, the bulb and leaves of D. delagoensis were tested for their antifungal efficacy against Aspergillus fumigatus. Eight crude extracts were further analysed to determine the volatile chemical components of the plant using one-dimensional gas chromatography coupled with the time of fight mass spectrometry. The compounds detected from GC-MS were further subjected to molecular docking study to determine prospective relationship between the analysed compounds (1–9) and the active site of the glucosamine-6-phosphate synthase. All the crude extracts were effective against A. fumigatus. However, it was observed that dichloromethane: methanol (1:1) mixture for the bulb extracts had a high minimum fungal concentration values of (7.8 μg/mL) followed by hexane (7.8 μg/ mL) and ethyl acetate (7.8 μg/mL). Compounds (9Z,12Z)-9,12-Octadecadienoic acid(R)-2,3-bis[[(E)-2-methyl-2-butenoyl] oxy]propyl ester and 9-Octadecenoic acid (9Z)-,1-methyl-1,2-ethanediyl ester had higher binding affinities of − 47.69 and − 62.36 kcal/mol, respectively when compared to amphotericin B standard drug (− 44.19 kcal/mol). Furthermore, lipophilicity values for ligands, which ranged from − 11.46 to − 27.07, were more significant than those for amphotericin B (− 19.66), and this greater significance could also be ascribed to the potency of the crude extracts against A. fumigatus.