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1.
RSC Adv ; 14(11): 7641-7654, 2024 Feb 29.
Article in English | MEDLINE | ID: mdl-38440276

ABSTRACT

High-purity reduced graphene oxide (RGO or rGO) with appreciable conductivity is a desired conductive filler for lightweight polymer composites used in coatings, electronics, catalysts, electromagnetic interference (EMI) shielding, and energy storage devices. However, the intrinsic conductivity and the uniform dispersion of RGO in relatively polar matrices are challenging, leading to poor overall conductivity and performance of the composite material. The reported study improved the RGO intrinsic conductivity by increasing its C/O ratio while also simultaneously enhancing its compatibility with the polyimide (PI) matrix through ester linkages for better dispersion. A two-step reduction method drastically increased the number of structural defects and carbon content in the resulting RGO, corresponding to a maximum ID/IG and C/O of 1.54 and ∼87, respectively. Moreover, the 2D nanosheets with limited hydroxyl (-OH) groups effectively interacted with anhydride-terminated polyamic acid (AT-PAA) through chemical linkages to make high-performance RGO/PI nanocomposites. Consequently, the polymer matrix composites possessed the highest direct current conductivity of 15.27 ± 0.61 S cm-1 for 20 wt% of the prepared RGO. Additionally, the composite material was highly stiff (3.945 GPa) yet flexible (easily bent through 180°), lightweight (∼0.34 g cm-3), and capable of forming thin films (162 ± 15 µm). Unlike most polymer matrix composites, it showcased one of its class's highest thermal stabilities (a weight loss of only 5% at 638 °C). Ultimately, the composite performed as an effective electromagnetic interference (EMI) shielding material in the X-Band (8 to 12 GHz), demonstrating outstanding shielding effectiveness (SE), shielding effectiveness per unit thickness (SEt), specific shielding effectiveness (SSE), and absolute shielding effectiveness (SSEt) of 46 dB, 2778 dB cm-2, 138 dB cm3 g-1, and 8358 dB cm2 g-1, respectively. As a consequence of this research, the high-purity RGO and its high-performance PI matrix nanocomposites are anticipated to find practical applications in conductive coatings and flexible substrates demanding high-temperature stability.

2.
Heliyon ; 10(6): e27573, 2024 Mar 30.
Article in English | MEDLINE | ID: mdl-38545176

ABSTRACT

One-dimensional polyaniline (PANI) nanostructures were synthesized in situ in the presence of two-dimensional (2D) Montmorillonite (MMT) clay nanosheets. Strong interactions between the polymer and MMT platelets in the nanocomposites were confirmed through spectroscopic studies. X-ray diffraction and scanning electron microscopic studies revealed the clay's profound effect on the polymer's crystallinity and morphology. The clay nanosheets induced higher crystallinity and well-defined nanorod morphology in the polymer structure. Consequently, the nanocomposite showed an electrical conductivity of 8.72 S/cm, closer to that of the pristine polymer (8.97 S/cm), despite the presence of highly insulting clay material. Surprisingly, a notable decrease in the optical bandgap of the polymer from 3.73 to 2.88 eV of the nanocomposite was also observed. This novel integration of a narrow band gap and high conductivity in PANI/MMT nanocomposites can expand their utility for visible light interactions in areas encompassing photocatalysis, photovoltaics, electro/photochromism, and related technologies.

3.
Plant Physiol Biochem ; 204: 108132, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37918078

ABSTRACT

Microplastics (MPx) and nanoplastics (NPx) are increasingly accumulating in terrestrial ecosystems, heightening concerns about their potential adverse effects on human health via the food chain. Techniques aimed at recovering the most challenging colloidal fractions of MPx and NPx, especially for analytical purposes, are limited. This systematic review emphasises the absence of a universal, efficient, and cost-effective analytical method as the primary hindrance to studying MPx and NPx in soil and plant samples. The study reveals that several methods, including density separation, organic matter removal, and filtration, are utilized to detect MPx or NPx in soil through vibrational spectroscopy and visual identification. Instruments such as Pyrolysis Gas Chromatography Mass Spectrometry (Py-GCMS), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) Spectroscopy, and fluorescence microscopy are employed to identify MPx and NPx in plant tissue. In extraction procedures, organic solvents and sonication are used to isolate NPx from plant tissues, while Pyrolysis GC-MS quantifies the plastics. SEM and TEM serve to observe and characterize NPx within plant tissues. Additionally, FTIR and fluorescence microscopy are utilized to identify polymers of MPx and NPx based on their spectral characteristics and fluorescence signals. The findings from this review clarify the identification and quantification methods for MPx and NPx in soil and plant systems and provide a comprehensive methodology for assessing MPx/NPx in the environment.


Subject(s)
Microplastics , Water Pollutants, Chemical , Humans , Microplastics/analysis , Plastics , Soil/chemistry , Ecosystem , Polymers
4.
Saudi J Biol Sci ; 30(6): 103646, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37181636

ABSTRACT

In current study the pharmaceutically active herbs was used against coccidiosis, caused by a protozoan: Eimeria, lead to $ 3 billion loss annually. The aqueous and methanolic extracts of whole plants were applied in-vitro to assess sporulation inhibition (spi) assay and calculated the inhibitory concentration (IC50). For in-vivo study 9 groups of 14 day old broiler chicks were infected with Eimeria tenella and three groups were treated different concentrations of methanolic extracts of Verbena officinalis and Polygonum glabrum post infection. The mean weight gain, oocyst count, diarrhea, biochemical tests, hematology, and histopathology of all groups were analyzed. The herbs were characterized by antioxidant assay, phytochemical screening, Fourier transmission and infrared (FT-IR), Ultra Violet-visible (UV-Vis) spectroscopy and Gas chromatography and mass spectroscopy (GC-MS). The GC-MS identified phyto-compounds of V. officinalis were docked with S-Adenosyl methionine (SAM) synthetase. The in-vitro study revealed that V. officinalis and P. glabrum have minimum IC50 of 0.14 and 12 mg/ml respectively. The in-vivo experiment showed that V. officinalis had significantly high anticoccidial potential with significant hematological profile like drug treated controls. The histology of treated chicks also showed recovery in the studied tissues. The antioxidant assay showed that V. officinalis have 4.19U/mg Superoxide dismutase (SOD) and 33.96 µM/mg Glutathione (GSH) quantities. The chemical characterization confirmed the presence of large number of organic compounds, however Flavonoids found only in V. officinalis, which suggests the anticoccidial potential of V. officinalis because flavonoids as antagonist of thiamine (Prinzo, 1999), because it promotes the carbohydrate synthesis required. Strychane, 1-acetyl-20a-hydroxy-16-methylene has best binding of with target protein with lowest binding score (-6.4 Kcal/mol), suggests its anticoccidial potential in poultry.

5.
Acta Trop ; 221: 105964, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34023304

ABSTRACT

The genetic diversity of Leishmania spp. in North Eastern Pakistan remains undetermined despite increased cases of cutaneous leishmaniasis (CL). This study was designed to decipher the molecular characterization and genetic diversity of Leishmania spp. in North Eastern Pakistan. Out of 13761 CL suspected cases, 567 cases were microscopically positive and confirmed as Leishmania spp. by internal transcribed spacer (ITS) gene amplification through the PCR- RFLP technique. Further, isolates were directly sequenced to conduct phylogenetic analysis for genetic diversity. Among suspected CL cases, Mirpur showed the highest proportion of CL infection with 4.85% (118/2431) of the cases, while the Neelum district showed the lowest percentage at 3.29% (9/273). The slide positivity rate, annual blood examination rate, and annual parasite incidence rate were 3.84, 0.27, and 0.01% respectively, and the incidence of CL in the age group 1-20 years old was higher in males (50.92%) than females (25.75%). The RFLP analysis and sequencing confirmed the occurrence of Leishmania tropica, Leishmania major, and Leishmania infantum. Leishmania tropica (p = 0.02) confirmed significantly higher nucleotides variation than L. major (p = 0.05). Current findings confirmed the prior assumption that anthroponotic CL is the primary CL form present in North Eastern Pakistan. Moreover, this is the first report based on molecular identification of L. major, and L. infantum from North Eastern Pakistan. This remarkable heterogeneity in the Leishmania spp. is the leading cause of treatment failure and emergence of new haplotypes. Therefore more extensive investigations are recommended from all geographical regions of North Eastern Pakistan, especially those using a large sample size.


Subject(s)
Leishmania tropica , Leishmaniasis, Cutaneous , Adolescent , Adult , Child , Child, Preschool , Female , Humans , Infant , Leishmania tropica/genetics , Leishmaniasis, Cutaneous/epidemiology , Male , Pakistan/epidemiology , Phylogeny , Polymorphism, Restriction Fragment Length , Young Adult
6.
Acta Trop ; 217: 105861, 2021 May.
Article in English | MEDLINE | ID: mdl-33587943

ABSTRACT

While Cutaneous leishmaniasis (CL) is not a life-threatening disease, it leads to devastating effects on local community. CL is widely scattered manifesting a noticeable epidemiological pattern around the globe. The present study was planned to address the role of Geographic Information System (GIS) using CL clinico-epidemiological data to determine the high-risk areas of CL. Recorded data (2014-2018) of 3630 positive individuals was collected from Basic Health Units of the Upper and Lower Dir Districts, Khyber Pakhtunkhwa, Pakistan. Descriptive and statistical analysis was used for clinico-epidemiological characterization. For spatial analysis, ArcGIS V.10.3 was used and the CL average incidence was tagged on the proportional, choropleth, and digital elevation model maps. For focal transmission and high-risk zones, Inverse Density Weight (IDW) spatial interpolation, focal statistics, hot spot, cluster and outlier, and Bayesian geostatistical analysis were used. The trend of CL cases was elevated from 2014 to 2016 except for 2017 and 2018. Individuals of both genders younger than 20 years old were highly susceptible. Single lesions were more prominent (56%) and frequently affected facial parts (51%). The size and pretreatment duration of the CL lesion was significantly associated. Spatially, a choropleth map displayed the maximum CL incidences in Tehsil Balambat, Khal, and Termergara (31%-13%) located within a range of 948-1947m elevation in the central regions with proximal CL transmissions. Hot spot and cluster and outlier analysis affirmed that Tehsil Khal was the high-risk CL foci. The Bayesian geostatistical analysis revealed high temperature, less altitude, and annual precipitation as important risk factors. An increasing trend in CL transmission has become evident, affecting both genders and <20 years old children. GIS resolute the concealed CL hubs in the least elevated central regions which warrant the control strategies to restrict future epidemics.


Subject(s)
Geographic Information Systems , Leishmaniasis, Cutaneous/epidemiology , Spatio-Temporal Analysis , Adolescent , Adult , Altitude , Bayes Theorem , Child , Female , Humans , Incidence , Male , Pakistan/epidemiology , Risk Factors , Temperature , Young Adult
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