scholarly journals Multifunctional activity of graphene oxide-based nanoformulation against the disease vector, Aedes aegypti

2021 ◽  
Vol 13 (4) ◽  
pp. 1265-1273
Author(s):  
Devaj Gupta ◽  
Roopa Rani Samal ◽  
Drashya Gautam ◽  
Sunita Hooda ◽  
Sarita Kumar
Keyword(s):  
Graphene Oxide ◽  
Aedes Aegypti ◽  
Binary Mixtures ◽  
Visible Spectrum ◽  
Disease Vector ◽  
Plasmon Peak ◽  
Global Concern ◽  
Mosquito Management ◽  
Uv Visible ◽  
Toxic Potential

Aedes aegypti management is a global concern due to the absence of medication and effective vaccines. The pesticide-mediated health hazards and rising insecticide resistance in mosquitoes have aggravated the issues. As graphene Oxide (GO)- based nanoformulations are considered a novel mosquito management strategy; the present investigation evaluated the efficacy of GO-based nanoformulations conjugated with malathion (ML) and endosulphan (EN) against Ae. aegypti. The GO was synthesised by Hummers’ method and was confirmed by UV-visible spectral analysis. The GO-ML and GO-EN binary mixtures (1:1 and 1:2) were assayed for toxic potential against mosquito larvae as per WHO protocol and the dead larvae were scrutinized for morphological deformations/abnormalities. The contact irritancy potential of GO nanoformulations was also evaluated against adult Ae. aegypti. The UV-visible spectrum of GO showed a narrow and high peak at ~300 nm corresponding to an n-π* plasmon peak. The GO-insecticide binary mixtures augmented the ML and EN toxicity by 80.43% and 6.43-fold, respectively. The GO-ML mixture-exposed larvae revealed cuticular deposition of black soot while larvae exposed to GO-EN exhibited disintegrated gut viscera. GO-insecticide combinations increased flights in Ae. aegypti denoting irritant potential. The effectual toxic, abrasive and irritant activity of GO-insecticide nanoformulations recommends developing graphene-based toxicants for mosquito management

scholarly journals Optical and Thermal Properties of Laser-Ablated Platinum Nanoparticles Graphene Oxide Composite

2019 ◽  
Vol 20 (24) ◽  
pp. 6153 ◽  
Author(s):  
Amir Reza Sadrolhosseini ◽  
Mina Habibiasr ◽  
Suhaidi Shafie ◽  
Hassan Solaimani ◽  
Hong Ngee Lim
Keyword(s):  
Graphene Oxide ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Thermal Lens ◽  
Platinum Nanoparticles ◽  
Volume Fraction ◽  
Thermal Effusivity ◽  
Visible Spectrum ◽  
Spherical Shape ◽  
Uv Visible

Platinum nanoparticles were synthesized in graphene oxide aqueous solution using a laser ablation technique to investigate the effect of optical linear, nonlinear and thermal properties of platinum-graphene oxide nanocomposite solution. The samples were prepared with different ablation times. The platinum nanoparticles that formed a spherical shape on the surface of graphene oxide solution were authenticated using UV-visible spectrum and transmission electron microscopy patterns. The particle size decreased with increasing ablation time, and the concentration and volume fraction of samples were increased. To obtain the optical linear, nonlinear and thermal properties of platinum-graphene oxide nanocomposite solution, UV-visible spectroscopy, Z-scan, thermal lens and photoacoustic techniques were used. Consequently, the linear and nonlinear refractive indices increased with an increase in the volume fraction of platinum nanoparticles. It was observed from the spatial self-phase modulation patterns that, the optical nonlinear property of the graphene oxide was enhanced in the presence of platinum nanoparticles, and the nonlinearity increased with an increase in the volume fraction of platinum nanoparticles inside the graphene oxide solution. The thermal diffusivity and thermal effusivity of platinum nanoparticles graphene oxide were measured using a thermal lens and photoacoustic methods, respectively. The thermal diffusivity and thermal effusivity of samples were in the range of 0.0341 × 10−5 m2/s to 0.1223 × 10−5 m2/s and 0.163 W s1/2 cm−2 K−1 to 0.3192 W s1/2 cm−2 K−1, respectively. Consequently, the platinum enhanced the optical and thermal properties of graphene oxide.

Liquid-liquid extraction of succinate using a dicopper cryptate

2020 ◽  
Author(s):  
Riccardo Mobili ◽  
Sonia La Cognata ◽  
Francesca Merlo ◽  
Andrea Speltini ◽  
Massimo Boiocchi ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Visible Spectrum ◽  
Tca Cycle ◽  
Residual Concentration ◽  
Waste Products ◽  
Liquid Liquid Extraction ◽  
The Tca Cycle ◽  
Quantitative Extraction ◽  
Uv Visible

<div> <p>The extraction of the succinate dianion from a neutral aqueous solution into dichloromethane is obtained using a lipophilic cage-like dicopper(II) complex as the extractant. The quantitative extraction exploits the high affinity of the succinate anion for the cavity of the azacryptate. The anion is effectively transferred from the aqueous phase, buffered at pH 7 with HEPES, into dichloromethane. A 1:1 extractant:anion adduct is obtained. Extraction can be easily monitored by following changes in the UV-visible spectrum of the dicopper complex in dichloromethane, and by measuring the residual concentration of succinate in the aqueous phase by HPLC−UV. Considering i) the relevance of polycarboxylates in biochemistry, as e.g. normal intermediates of the TCA cycle, ii) the relevance of dicarboxylates in the environmental field, as e.g. waste products of industrial processes, and iii) the recently discovered role of succinate and other dicarboxylates in pathophysiological processes including cancer, our results open new perspectives for research in all contexts where selective recognition, trapping and extraction of polycarboxylates is required. </p> </div>

Graphene Oxide as a Substrate for Biosensors: Synthesis and Characterization

2021 ◽  
Vol 324 ◽  
pp. 87-93
Author(s):  
Mohamed Adel ◽  
Abdel Hady A. Abdel-Wahab ◽  
Ahmed Abdel-Mawgood ◽  
Ahmed Osman Egiza
Keyword(s):  
Raman Spectroscopy ◽  
Graphene Oxide ◽  
Acidic Solution ◽  
Cost Effective ◽  
Sem Analysis ◽  
Visible Spectroscopy ◽  
Sem Images ◽  
Hummers Method ◽  
Uv Visible ◽  
Modified Hummers Method

Graphene oxide (GO) is an oxidized nanosheets of graphite with a 2D planar structure. GO could be readily complexed with bio-entities as it possesses many oxygen-containing functionalities on its surface. The preparation process is fast, easy, and cost-effective. It was prepared using modified Hummers’ method in acidic solution as a primary solvent and potassium permanganate as an oxidizing agent. Afterwards, it was successfully characterized by FTIR, UV-visible spectroscopy, as well as XRD and Raman spectroscopy, and finally, SEM analysis. It was observed that the formed GO is mainly composed of carbon and oxygen elements rich in oxygen functional groups. Furthermore, the existence of (001) plane in XRD interprets the complete oxidation of graphite with d-spacing 9 Å. Moreover, Raman spectroscopy displayed the sp3 carbon hybridization, besides, the ID/IG ratio is found to be 0.84, which confirms the disorder between graphene oxide layers. The SEM images also pointed out that graphene oxide sheets were regularly stacked together as flake-like structures. Accordingly, the richness of oxygen-containing functionalities was confirmed. Hence, it is appropriate to be used as a base transducer for biosensing applications.

Synthesis of Amino-Functionalized Graphene Oxide/Azobenzene Polyimide and its Simulation of Optical Switches

2017 ◽  
Vol 231 (11-12) ◽  
Author(s):  
Tianlin Cao ◽  
Fanyu Zhao ◽  
Zulin Da ◽  
Fengxian Qiu ◽  
Dongya Yang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Near Infrared ◽  
Optical Switches ◽  
Attenuated Total Reflection ◽  
Functionalized Graphene ◽  
Visible Spectroscopy ◽  
Scanning Calorimetry ◽  
Functionalized Graphene Oxide ◽  
Uv Visible ◽  
532 Nm

AbstractIn this work, an amino-functionalized graphene oxide (AFGO) was synthesized by graphene oxide (GO) and ethylene diamine. A novel amino-functionalized graphene oxide/azobenzene polyimide (AFGO/ACPI) was synthesized with AFGO, azobenzene chromophore and pyromellitic dianhydride (PMDA). The structure, mechanical and thermal property of AFGO/ACPI were characterized and measured by fourier transform infrared, UV-visible spectroscopy, near-infrared spectrum, thermogravimetric analysis and differential scanning calorimetry. To obtain the refractive index of AFGO/ACPI at different temperature and wavelength (532 nm, 650 nm and 850 nm), the attenuated total reflection (ATR) method was used to measure, and thermo optic coefficients (dn/dT) were −7.22×10

Photoactive amphiphiles for the assembly of supramolecular architectures

2015 ◽  
Vol 185 ◽  
pp. 471-479 ◽  
Author(s):  
B. P. Jarman ◽  
F. Cucinotta
Keyword(s):  
Visible Spectrum ◽  
Solid Materials ◽  
Visible Absorption ◽  
Optical Components ◽  
Absorption And Emission ◽  
X Ray ◽  
Supramolecular Architectures ◽  
Uv Visible ◽  
Absorption And Emission Spectroscopy ◽  
Molecular Organisation

The presented study reports the use of photoactive templating structures for the design of porous frameworks with built-in optical functionalities. The materials have been synthesised and characterised using powder X-ray diffractometry, UV-visible absorption and emission spectroscopy. The latter shows that, by varying the relative amount of an amphiphilic chromophore in the micellar templates, it is possible to tune the light absorption and emission properties over the visible spectrum, by means of controlling the molecular organisation and the excitonic coupling of aggregated species. This enables versatile solid materials that can be used as optical components for light-harvesting and converting systems to be obtained .

scholarly journals Larval Diet Abundance Influences Size and Composition of the Midgut Microbiota of Aedes aegypti Mosquitoes

2021 ◽  
Vol 12 ◽  
Author(s):  
Hannah J. MacLeod ◽  
George Dimopoulos ◽  
Sarah M. Short
Keyword(s):  
Aedes Aegypti ◽  
Bacterial Load ◽  
Amplicon Sequencing ◽  
Larval Diet ◽  
Microbiota Composition ◽  
Vector Species ◽  
Larval Food ◽  
Disease Vector ◽  
16S Amplicon Sequencing ◽  
The Impact

The midgut microbiota of the yellow fever mosquito Aedes aegypti impacts pathogen susceptibility and transmission by this important vector species. However, factors influencing the composition and size of the microbiome in mosquitoes are poorly understood. We investigated the impact of larval diet abundance during development on the composition and size of the larval and adult microbiota by rearing Aedes aegypti under four larval food regimens, ranging from nutrient deprivation to nutrient excess. We assessed the persistent impacts of larval diet availability on the microbiota of the larval breeding water, larval mosquitoes, and adult mosquitoes under sugar and blood fed conditions using qPCR and high-throughput 16S amplicon sequencing to determine bacterial load and microbiota composition. Bacterial loads in breeding water increased with increasing larval diet. Larvae reared with the lowest diet abundance had significantly fewer bacteria than larvae from two higher diet treatments, but not from the highest diet abundance. Adults from the lowest diet abundance treatment had significantly fewer bacteria in their midguts compared to all higher diet abundance treatments. Larval diet amount also had a significant impact on microbiota composition, primarily within larval breeding water and larvae. Increasing diet correlated with increased relative levels of Enterobacteriaceae and Flavobacteriaceae and decreased relative levels of Sphingomonadaceae. Multiple individual OTUs were significantly impacted by diet including one mapping to the genus Cedecea, which increased with higher diet amounts. This was consistent across all sample types, including sugar fed and blood fed adults. Taken together, these data suggest that availability of diet during development can cause lasting shifts in the size and composition of the microbiota in the disease vector Aedes aegypti.

scholarly journals The Impact of Hurricane Irma on Our Community and the Collier Mosquito Control District's Mission

2020 ◽  
Vol 36 (2s) ◽  
pp. 11-14
Author(s):  
Robin A. King ◽  
Rebecca Heinig ◽  
Patrick Linn ◽  
Keira J. Lucas
Keyword(s):  
Mosquito Control ◽  
Electrical Power ◽  
Southwest Florida ◽  
Disease Vector ◽  
Collier County ◽  
Mosquito Management ◽  
The Impact ◽  
Integrated Mosquito Management ◽  
Hurricane Irma ◽  
Subtropical Environment

ABSTRACT The Collier Mosquito Control District, located in southwest Florida, is uniquely positioned in a subtropical environment between the Gulf of Mexico and Everglades National Park. The District's mission is focused on the control of disease vector and nuisance mosquitoes in Collier County, which is accomplished through integrated mosquito management. Hurricane Irma made landfall in the county on September 10, 2017, leaving in its wake tremendous property and infrastructure damage, and it also disrupted communications and airport operations. These factors greatly affected the District's operations and its ability to meet its mission. In addition, the lengthy loss of electrical power forced most residents outdoors, increasing their exposure to mosquitoes. From challenges in completing poststorm treatments to outdated policies that caught us off-guard, the event prompted a new hurricane policy and plan to ensure improved preparedness for the next natural disaster. The poststorm environment also provided a rich foundation for research into mosquito populations after tropical disturbances of this scale. Here we report the impact on the District's aerial mosquito control operations, changes to internal policies, and mosquito population abundance following Hurricane Irma.

scholarly journals Liquid-liquid extraction of succinate using a dicopper cryptate

2020 ◽  
Author(s):  
Riccardo Mobili ◽  
Sonia La Cognata ◽  
Francesca Merlo ◽  
Andrea Speltini ◽  
Massimo Boiocchi ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Visible Spectrum ◽  
Tca Cycle ◽  
Residual Concentration ◽  
Waste Products ◽  
Liquid Liquid Extraction ◽  
The Tca Cycle ◽  
Quantitative Extraction ◽  
Uv Visible

<div> <p>The extraction of the succinate dianion from a neutral aqueous solution into dichloromethane is obtained using a lipophilic cage-like dicopper(II) complex as the extractant. The quantitative extraction exploits the high affinity of the succinate anion for the cavity of the azacryptate. The anion is effectively transferred from the aqueous phase, buffered at pH 7 with HEPES, into dichloromethane. A 1:1 extractant:anion adduct is obtained. Extraction can be easily monitored by following changes in the UV-visible spectrum of the dicopper complex in dichloromethane, and by measuring the residual concentration of succinate in the aqueous phase by HPLC−UV. Considering i) the relevance of polycarboxylates in biochemistry, as e.g. normal intermediates of the TCA cycle, ii) the relevance of dicarboxylates in the environmental field, as e.g. waste products of industrial processes, and iii) the recently discovered role of succinate and other dicarboxylates in pathophysiological processes including cancer, our results open new perspectives for research in all contexts where selective recognition, trapping and extraction of polycarboxylates is required. </p> </div>

Liquid exfoliation of graphene oxide nanoribbons using chemical assisted laser ablation

2021 ◽  
pp. 2140009
Author(s):  
Siddhant Dhongade ◽  
Pankaj Koinkar ◽  
Akihiro Furube ◽  
Satoshi Sugano
Keyword(s):  
Graphene Oxide ◽  
Laser Ablation ◽  
2D Materials ◽  
Visible Spectroscopy ◽  
Liquid Exfoliation ◽  
Graphene Oxide Nanoribbons ◽  
Laser Ablation Method ◽  
Structural Details ◽  
Uv Visible ◽  
Optical Applications

The interest toward two-dimensional (2D) materials is gradually increasing because of their structure at nanoscale and great importance for electronic and optical applications. In this study, we show the synthesis of graphene oxide (GO) micro-ribbons fabricated by chemical assisted-laser ablation method. In order to confirm the formation of GO, UV-visible spectroscopy (UV-vis) and Raman spectroscopy are used to observe the surface morphological feature and structural details. In addition, a possible mechanism for the growth of GO nanoribbon is discussed. This work indicates a new method to develop GO nanostructures and related nanomaterials.

The Global Expansion of Dengue: How Aedes aegypti Mosquitoes Enabled the First Pandemic Arbovirus

2020 ◽  
Vol 65 (1) ◽  
pp. 191-208 ◽  
Author(s):  
Oliver J. Brady ◽  
Simon I. Hay
Keyword(s):  
Invasive Species ◽  
Aedes Aegypti ◽  
Infectious Diseases ◽  
Control Strategies ◽  
Viral Disease ◽  
Rapid Rise ◽  
Disease Vector ◽  
Research Priority ◽  
Global Spread ◽  
Human Habitation

Dengue is an emerging viral disease principally transmitted by the Aedes ( Stegomyia) aegypti mosquito. It is one of the fastest-growing global infectious diseases, with 100–400 million new infections a year, and is now entrenched in a growing number of tropical megacities. Behind this rapid rise is the simple adaptation of Ae. aegypti to a new entomological niche carved out by human habitation. This review describes the expansion of dengue and explores how key changes in the ecology of Ae. aegypti allowed it to become a successful invasive species and highly efficient disease vector. We argue that characterizing geographic heterogeneity in mosquito bionomics will be a key research priority that will enable us to better understand future dengue risk and design control strategies to reverse its global spread.

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