List of Titles

Investigation of electrocatalytic behaviour of low symmetry cobalt phthalocyanines when clicked to azide grafted carbon electrodes

- Mpeta, Lakethe S, Sen, Pinar, Nyokong, Tebello

Authors: Mpeta, Lakethe S , Sen, Pinar , Nyokong, Tebello
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/186304 , vital:44483 , xlink:href="https://doi.org/10.1016/j.jelechem.2020.113896"
Description: This work describes the electrochemical properties of low symmetry cobalt phthalocyanines namely, tris-[(4-tert-butylphenoxy)-4-(pent-4-yn-1-yloxy) phthalocyaniato] cobalt (II) (3) and tris-[(4-tert-butylphenoxy)-4-(4-ethybylbenzyl-oxy) phthalocyaniato] cobalt (II) (5). The complexes were characterized by a number of techniques including UV–Vis, mass, and infrared spectra, as well as elemental analysis. The glassy carbon electrodes were first azide functionalized then clicked to low symmetry phthalocyanines. The click reaction was confirmed using X-ray photoelectron spectra. The constructed electrodes showed excellent electrocatalytic activity towards hydrazine oxidation. Oxidation peaks with low potentials of 0.21 V and 0.26 V, for complexes 3 and 5, respectively were obtained. Complex-5 gave a better detection limit of 0.94 μM and electrocatalytic rate constant of 5.6 × 106 M−1 s−1.
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Date Issued: 2020

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Long Waves of Strikes in South Africa: 1886–2019

- Cottle, Eddie

Authors: Cottle, Eddie
Date: 2020
Subjects: Strikes and lockouts South Africa , Long waves (Economics) South Africa , Business cycles South Africa , Industrial mobilization South Africa , Collective bargaining South Africa , Institutionalisation , Labor unions South Africa
Language: English
Type: thesis , text , Doctoral , PhD
Identifier: http://hdl.handle.net/10962/163228 , vital:41020 , doi:10.21504/10962/163228
Description: Thesis (PhD)--Rhodes University, Faculty of Humanities, Institute for Social and Economic Research (ISER), 2020.
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Date Issued: 2020

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Men in Women’s Clothes

- Jones, Ward E

Authors: Jones, Ward E
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/275658 , vital:55067 , xlink:href="https://doi.org/10.1111/sjp.12394"
Description: The descriptive phrase that comprises my title can refer both to a pervasive comic trope and a mode of self-expression. There is a tension here, insofar as the comic trope leads us not to take cross-dressing, or drag, seriously. The first half of the comic film Some Like It Hot (1959), with its cross-gender plot and its (sophisticated but) straightforward use of the comic trope of men-in-women’s clothes, appears to fall foul of this tension and to be susceptible to criticism in this regard. However, the film rectifies itself, portraying the cross-dressing relationship which develops through the second half of the film as a potentially meaningful one for both partners. In this article, I interpret the film as inviting its viewers to adopt a (particular kind of) skeptical ironic (that is, Pyrrhonian) attitude toward gender-presentation practices. While the film in no way attempts to discourage us from participating in such practices, it does invite us—through our partiality toward the characters Osgood and Jerry/Daphne, as we follow their budding, transgressive relationship—to acknowledge that a violation of gender-presentation practices can be a meaningful feature of sincere relationships.
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Date Issued: 2020

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Modern supratidal microbialites fed by groundwater: functional drivers, value and trajectories

- Rishworth, Gavin M, Dodd, Carla, Perissinotto, Renzo, Bornman, Thomas G, Adams, Janine B, Anderson, Callum R, Cawthra, Hayley C, Dorrington, Hayley C, du Toit, Hendrik, Edworthy, Carla, Gibb, Ross-Lynne A, Human, Lucienne R D, Isemonger, Eric W, Lemley, David A, Miranda, Nelson A, Peer, Nasreen, Raw, Jacqueline L, Smith, Alan M, Steyn, Paul-Pierre, Strydom, Nadine A, Teske, Peter R, Welman, Peter R

Authors: Rishworth, Gavin M , Dodd, Carla , Perissinotto, Renzo , Bornman, Thomas G , Adams, Janine B , Anderson, Callum R , Cawthra, Hayley C , Dorrington, Hayley C , du Toit, Hendrik , Edworthy, Carla , Gibb, Ross-Lynne A , Human, Lucienne R D , Isemonger, Eric W , Lemley, David A , Miranda, Nelson A , Peer, Nasreen , Raw, Jacqueline L , Smith, Alan M , Steyn, Paul-Pierre , Strydom, Nadine A , Teske, Peter R , Welman, Peter R
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/426008 , vital:72306 , xlink:href="https://doi.org/10.1016/j.earscirev.2020.103364"
Description: Microbial mats were the dominant habitat type in shallow marine environments between the Palaeoarchean and Phanerozoic. Many of these (termed ‘microbialites’) calcified as they grew but such lithified mats are rare along modern coasts for reasons such as unsuitable water chemistry, destructive metazoan influences and competition with other reef-builders such as corals or macroalgae. Nonetheless, extant microbialites occur in unique coastal ecosystems such as the Exuma Cays, Bahamas or Lake Clifton and Hamelin Pool, Australia, where limitations such as calcium carbonate availability or destructive bioturbation are diminished. Along the coast of South Africa, extensive distributions of living microbialites (including layered stromatolites) have been discovered and described since the early 2000s. Unlike the Bahamian and Australian ecosystems, the South African microbialites form exclusively in the supratidal coastal zone at the convergence of emergent groundwater seepage. Similar systems were documented subsequently in southwestern Australia, Northern Ireland and the Scottish Hebrides, as recently as 2018, revealing that supratidal microbialites have a global distribution. This review uses the best-studied formations to contextualise formative drivers and processes of these supratidal ecosystems and highlight their geological, ecological and societal relevance.
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Date Issued: 2020

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Monitoring and evaluation in a changing world: A Southern African perspective on the skills needed for a new approach

- Rosenberg, Eureta, Kotschy, Karen

Authors: Rosenberg, Eureta , Kotschy, Karen
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/370711 , vital:66369 , xlink:href="https://doi.org/ 10.4102/aej.v8i1.472"
Description: Background: As science and modern technology have brought many advances, we have also come to overshoot planetary boundaries, while still falling short of development goals to eradicate poverty and inequality. A growing recognition of the complexity of development problems and contexts calls for new framings, including a new approach to monitoring and evaluation (M and E) as one of the mechanisms by which modern societies aim to steer towards a more sustainable future. New approaches to M and E mean new skills for the M and E practitioner. Objectives: This article proposed a framing for M and E skills, comprising of technical, relational and transformational (T-R-T) competences. Method: Adapted from the literature, this competence framework was tested in a broader learning needs assessment and then applied retrospectively to author’s experience in developmental evaluations in complex social–ecological contexts in southern Africa. Results: The emerging insights were that not only technical competence is needed, but also relational competence that goes beyond interpersonal skills, to enable the production and uptake of evaluation findings. In addition, the limitations of mainstream M and E methods in the face of complexity seemed to create a need for ‘transformational’ competence, which included evaluators’ ability to develop credible M and E alternatives. Conclusion: The T-R-T framework helped to advance the notions of ‘hard’ and ‘soft’ skills and expanded on existing M and E competence frameworks. Recommendations included a call for innovative educational and professional development approaches to develop relational and transformational competencies, in addition to training for technical competence.
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Date Issued: 2020

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Multi-layered risk management in under-resourced antenatal clinics

- Feltham-King, Tracey, Macleod, Catriona I

Authors: Feltham-King, Tracey , Macleod, Catriona I
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/298561 , vital:57716 , xlink:href="https://doi.org/10.1080/13698575.2019.1697432"
Description: In this article we contribute to critical risk approaches to studying pregnancy and childbirth in the global South. Following Sarah Rudrum’s work, our approach focusses on sociocultural inequalities amid the regulation of individuals. We draw on data from our Foucauldian-inspired ethnography of two antenatal clinics in an under-resourced area of South Africa to illustrate how multi-layered risk management operates in these spaces. These data were collected over a period of six months in the form of semi-structured interviews, observations of consultations and waiting room interactions, documents used in the clinic, and posters appearing on the clinic walls. Our findings show how a scientific-bureaucratic approach to pregnancy risk management, as encoded in international, national and institutional guidelines, is well known, highly visible, and practised through surveillance and reporting mechanisms in clinics. This approach incites healthcare practitioners to achieve particular performance standards and to monitor their professional agency. Managing pregnancy risk thus entails regulating the healthcare practitioners themselves. In implementing approved pregnancy risk management strategies in an over-subscribed and under-resourced public healthcare setting, however, healthcare practitioners face potential risk to their professional reputation and integrity. In managing this risk, they resist the scientific-bureaucratic approach through: depicting themselves as victims of unfair institutional arrangements or unreasonable patients; instituting street-level bureaucracy to control access to the clinics; and controlling patients’ actions in authoritarian ways. Our research shows that without engagement with the on-the-ground realities of the antenatal clinic in resource-poor environments, a scientific-bureaucratic approach to pregnancy risk management is inevitably limited in its effectiveness.
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Date Issued: 2020

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Mycorrhizal Interventions for Sustainable Potato Production in Africa

- Chifetete, Varaidzo W, Dames, Joanna

Authors: Chifetete, Varaidzo W , Dames, Joanna
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/426021 , vital:72307 , xlink:href="https://doi.org/10.3389/fsufs.2020.593053"
Description: The potato (Solanum tuberosum L.) is an important tuber crop with high dietary value that could potentially help to alleviate malnutrition and hunger in Africa. However, production is expensive, with high fertilizer and pesticide demands that lead to environmental pollution, and tillage practices that negatively affect soil structure. Microorganisms of different types have increasingly been found to be useful as biofertilizers, and arbuscular mycorrhizal (AM) fungi are an important crop symbiont. AM fungi have been shown to increase tolerance of crop plants to drought, salinity and disease by facilitating water and nutrient acquisition and by improving overall soil structure. However, the establishment and maintenance of the symbioses are greatly affected by agricultural practices. Here, we review the benefits that AM fungi confer in potato production, discuss the role and importance of mycorrhiza helper bacteria, and focus on how AM fungal diversity and abundance can be affected by conventional agricultural practices, such as those used in potato production. We suggest approaches for maintaining AM fungal abundance in potato production by highlighting the potential of conservation tillage practices augmented with cover crops and crop rotations. An approach that balances weed control, nutrient provision, and AM fungal helper bacterial populations, whilst promoting functional AM fungal populations for varying potato genotypes, will stimulate efficient mycorrhizal interventions.
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Date Issued: 2020

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Nano-biomimetic drug delivery vehicles: Potential approaches for COVID-19 treatment

- Witika, Bwalya A, Makoni, Pedzisai A, Mweetwa, Larry L, Ntemi, Pascal V, Chikukwa, Mellisa T R, Matafwali, Scott K, Mwila, Chiluba, Mudenda, Steward, Katandula, Jonathan, Walker, Roderick B

Authors: Witika, Bwalya A , Makoni, Pedzisai A , Mweetwa, Larry L , Ntemi, Pascal V , Chikukwa, Mellisa T R , Matafwali, Scott K , Mwila, Chiluba , Mudenda, Steward , Katandula, Jonathan , Walker, Roderick B
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/183440 , vital:43991 , xlink:href="https://doi.org/10.3390/molecules25245952"
Description: The current COVID-19 pandemic has tested the resolve of the global community with more than 35 million infections worldwide and numbers increasing with no cure or vaccine available to date. Nanomedicines have an advantage of providing enhanced permeability and retention and have been extensively studied as targeted drug delivery strategies for the treatment of different disease. The role of monocytes, erythrocytes, thrombocytes, and macrophages in diseases, including infectious and inflammatory diseases, cancer, and atherosclerosis, are better understood and have resulted in improved strategies for targeting and in some instances mimicking these cell types to improve therapeutic outcomes. Consequently, these primary cell types can be exploited for the purposes of serving as a "Trojan horse" for targeted delivery to identified organs and sites of inflammation. State of the art and potential utilization of nanocarriers such as nanospheres/nanocapsules, nanocrystals, liposomes, solid lipid nanoparticles/nano-structured lipid carriers, dendrimers, and nanosponges for biomimicry and/or targeted delivery of bioactives to cells are reported herein and their potential use in the treatment of COVID-19 infections discussed. Physicochemical properties, viz., hydrophilicity, particle shape, surface charge, composition, concentration, the use of different target-specific ligands on the surface of carriers, and the impact on carrier efficacy and specificity are also discussed.
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Date Issued: 2020

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New difluoroboron complexes based on N, O-chelated Schiff base ligands: Synthesis, characterization, DFT calculations and photophysical and electrochemical properties

- Sen, Pinar, Mpeta, Lekhetho S, Mack, John, Nyokong, Tebello

Authors: Sen, Pinar , Mpeta, Lekhetho S , Mack, John , Nyokong, Tebello
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/186207 , vital:44473 , xlink:href="https://doi.org/10.1016/j.jlumin.2020.117262"
Description: The synthesis of new Schiff bases and their dinuclear boron complexes is described, along with their characterization by 1H and 13C NMR, FT-IR, and UV–visible absorption spectroscopy, mass spectrometry, and EDX for elemental analysis. The optical and photophysical properties were examined in terms of their absorption and emission behavior, fluorescence quantum yields and fluorescence lifetimes. The flexible dinuclear boron complexes that are linked by a flexible carbon chain exhibited large Stokes shifts in the range from 92 nm to 115 nm in contrast to BODIPY dyes. Those properties make these complexes precious for applications in fluorescence materials. And also theoretical calculations were obtained by using Density Functional Theory (DFT) methods.
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Date Issued: 2020

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NIR Absorbing AzaBODIPY Dyes for pH Sensing

- Kubheka, Gugu, Mack, John, Nyokong, Tebello, Zhen, Shen

Authors: Kubheka, Gugu , Mack, John , Nyokong, Tebello , Zhen, Shen
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/186668 , vital:44523 , xlink:href="https://doi.org/10.3390/molecules25163689"
Description: Two near-infrared (NIR) absorbing di(thien-2-nyl)-di(dimethylanilino)azaBODIPY dyes 2a and 2b were synthesized and characterized that differ depending on whether the dimethylaniline substituents are introduced at the 3,5- or 1,7-positions of the azaBODIPY core. The main spectral bands lie at 824 and 790 nm, respectively, in CH2Cl2. The effect of substituent position on the photophysical and pH sensing properties was analyzed through a comparison of the optical properties with the results of time-dependent density functional theory (TD-DFT) calculations. Protonation of the dimethylamino nitrogen atoms eliminates the intramolecular charge transfer properties of these compounds, and this results in a marked blue-shift of the main absorption bands to 696 and 730 nm, respectively, in CH2Cl2, and a fluorescence “turn-on” effect in the NIR region. The pH dependence studies reveal that the pKa values of the non-protonated 2a and 2b molecules are ca. 6.9 (±0.05) and 7.3 (±0.05), respectively, while that of the monoprotonated species for both dyes is ca. 1.4 (±0.05) making them potentially suitable for use as colorimetric pH indicators under highly acidic conditions.
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Date Issued: 2020

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Nonlinear optical response and electrocatalytic activity of cobalt phthalocyanine clicked zinc oxide nanoparticles

- Mpeta, Lekhetho S, Sekhosana, Kutloano E, Nyokong, Tebello

Authors: Mpeta, Lekhetho S , Sekhosana, Kutloano E , Nyokong, Tebello
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/186179 , vital:44471 , xlink:href="https://doi.org/10.1016/j.ica.2020.119661"
Description: In this article, we report on the linking of cobalt tetrakis (4-pentyn-oxy) phthalocyanine (CoTPPc) to ZnO nanoparticles via click chemistry. Subsequently, electrocatalytic activity and nonlinear optical properties were investigated (the latter using an open Z-scan technique at 532 nm). The linking of CoTPPc with ZnO resulted in the lowest limiting intensity value of 0.27 J.Cm−2, the βeff (cmW−1) values were found to be 1.51 × 10-8 and 7.10 × 104 for ZnO and CoTPPc-ZnO respectively. The catalytic rate constants (M−1s−1) (and limits of detection) were 4.1 × 104 (12.87 µM), 5.7 × 104 (8.62 µM) and 7.36 × 104 (4.35 µM) for ZnO, CoTPPc and CoTPPc-ZnO. Hence linking ZnO nanoparticles to CoTPPc result in the enhancement of both nonlinear optical behaviour and catalytic activity.
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Date Issued: 2020

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Nutrient-mediated silica uptake from agricultural runoff in invasive floating macrophytes: implications for biological control

- Baso, Nompumelelo C, Delport, Garyn A, Coetzee, Julie A

Authors: Baso, Nompumelelo C , Delport, Garyn A , Coetzee, Julie A
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/424803 , vital:72185 , xlink:href="https://doi.org/10.1007/s10750-020-04344-5"
Description: Silica (Si) plays a significant role in alleviating the effects of biotic and abiotic stressors in many plants, especially in an agricultural context. With increased use of Si-based fertilisers, understanding plant responses to the addition of Si to their environment, particularly aquatic environments, is important. We investigated how two invasive macrophytes, Eichhornia crassipes and Pistia stratiotes, responded to different nutrient and Si concentrations, in the presence and absence of herbivory. Both species incorporated Si into their foliage, but uptake of Si did not increase under high nutrient availability but rather decreased, especially in P. stratiotes. Plant quality (i.e. C:N) for both weed species was affected more by nutrient concentrations than Si content, and the addition of Si had a negative effect on plant growth. Eichhornia crassipes increased daughter plant production under high Si conditions, while P. stratiotes plants showed no reproductive response to increased Si except in low nutrient conditions where reproduction was reduced. The addition of Si resulted in increased biomass of E. crassipes, while P. stratiotes was unaffected. These results highlight that runoff of Si from fertiliser alter aquatic plant–insect interactions, which has consequences for biological control.
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Date Issued: 2020

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On the move: New insights on the ecology and management of native and alien macrophytes

- Hofstra, Deborah, Schoelynck, Jonas, Ferrell, Jason, Coetzee, Julie A, de Winton, Mary, Bickel, Tobias O, Champion, Paul, Madsen, John, Bakker, Elisabeth S, Hilt, Sabine, Matheson, Fleur, Netherland, Mike, Gross, Elisabeth M

Authors: Hofstra, Deborah , Schoelynck, Jonas , Ferrell, Jason , Coetzee, Julie A , de Winton, Mary , Bickel, Tobias O , Champion, Paul , Madsen, John , Bakker, Elisabeth S , Hilt, Sabine , Matheson, Fleur , Netherland, Mike , Gross, Elisabeth M
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/419346 , vital:71636 , xlink:href=" https://doi.org/10.1016/j.aquabot.2019.103190"
Description: Globally, freshwater ecosystems are under threat. The main threats come from catchment land-use changes, altered water regimes, eutrophication, invasive species, climate change and combinations of these factors. We need scientific research to respond to these challenges by providing solutions to halt the deterioration and improve the condition of our valuable freshwaters. This requires a good understanding of aquatic ecosystems, and the nature and scale of changes occurring. Macrophytes play a fundamental role in aquatic systems. They are sensitive indicators of ecosystem health, as they are affected by run-off from agricultural, industrial or urban areas. On the other hand, alien macrophytes are increasingly invading aquatic systems all over the world. Improving our knowledge on the ecology and management of both native and alien plants is indispensable to address threats to freshwaters in order to protect and restore aquatic habitats. The International Aquatic Plants Group (IAPG) brings together scientists and practitioners based at universities, research and environmental organisations around the world. The main themes of the 15th symposium 2018 in New Zealand were biodiversity and conservation, management, invasive species, and ecosystem response and restoration. This Virtual Special Issue provides a comprehensive review from the symposium, addressing the ecology of native macrophytes, including those of conservation concern, and highly invasive alien macrophytes, and the implications of management interventions. In this editorial paper, we highlight insights and paradigms on the ecology and management of native and alien macrophytes gathered during the meeting.
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Date Issued: 2020

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Optical limiting properties of D-π-A BODIPY dyes in the presence and absence of methyl groups at the 1, 7-positions

- May, Aviwe K, Mack, John, Nyokong, Tebello

Authors: May, Aviwe K , Mack, John , Nyokong, Tebello
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/186146 , vital:44468 , xlink:href="https://doi.org/10.1142/S1088424620500315"
Description: The optical limiting properties of three meso-pentafluorophenylstyrylBODIPY dyes are investigated in the presence and absence of methyl groups at the 1,7-positions that hinder free rotation of the meso-aryl group. Pentafluorophenyl groups are introduced at the meso-position, while 4-diethylaminostyryl groups are introduced at the 3- and/or 5-positions to form dyes with strong donor-ππ-acceptor (D-ππ-A) properties to enhance the dipole moment of the molecule. Favorable optical limiting properties are obtained for all three dyes, with the highest second-order hyperpolarizability value obtained for a monostyryl dye with no methyl groups at the 1,7-position. Bromination at the 2,6-positions of a 1,7-methyl substituted dye is found to result in second-order hyperpolarizability that is an order of magnitude lower than that calculated for the analogous non-halogenated dye.
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Date Issued: 2020

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