Objective: This paper introduces a simple one-step and ultra-fast method for synthesis of highly photothermally active polypyrrole-coated gold nanoparticles. The synthesis process is so simple that the reaction is very fast without the need for any additives or complicated steps. Methodology: Polypyrrole-coated gold nanoparticles (AuPpy NPs) were synthesized by reacting chloroauric acid (HAuCl₄) with pyrrole (monomer) in aqueous medium at room temperature. These nanoparticles were characterized by UV–visible–NIR spectrometry, transmission electron microscopy (TEM), AC conductivity, zeta sizer and were evaluated for dark cytotoxicity and photocytotoxicity using human hepatocellular carcinoma (HepG2) cell line as a model for cancer cells. Results: The synthesized AuPpy NPs showed a peak characteristic for gold nanoparticles (530– 600 nm, molar ratio dependent) and a wide absorption band along the visible–NIR region with intensity about triple or even quadruple that of polypyrrole synthesized by the conventional FeCl₃ method at the same concentration and under the same conditions. TEM imaging showed that the synthesized AuPpy NPs were composed of spherical or semi-spherical gold core(s) of about 4– 10 nm coated with distinct layer(s) of polypyrrole seen either loosely or in clusters. Mean sizes of the synthesized nanoparticles range between ∼ 25 and 220 nm (molar ratio dependent). Zeta potentials of the AuPpy NPs preparations indicate their good colloidal stability. AC conductivity values of AuPpy NPs highly surpass that of Ppy prepared by the conventional FeCl₃ method. AuPpy NPs were non-toxic even at high concentrations (up to 1000 μM pyrrole monomer equivalent) under dark conditions. Unlikely, light activated the photothermal activity of AuPpy NPs in a dose-dependent manner. Conclusion: This method simply and successfully synthesized AuPpy NPs nanoparticles that represent a safe alternative photothermally active multifunctional tool instead of highly toxic and non-biodegradable gold nanorods.

The control of the camel tick, Hyalomma dromedarii is very crucial. This study evaluated the novel toxicity of photosensitizers and Phoxim insecticide against H. dromedarii males using the adult immersion tests. Ticks were subjected to sunlight for 10 min post-treatment (PT). The optical characters of the applied materials were determined by UV–Vis spectroscopy (250–900 nm wavelengths). The intensity of spectra decreased as dye concentration decreased. The optical bandgap energies of the dyes at different concentrations were not changed as the concentration changed and decreased as the absorption peak of individual dyes red-shifted. The mortalities 72 h PT reached 42.2%, 44.4%, 51.1%, 71.1%, 46.7%, 48.9%, 44.4%, and 55.6% for chlorophyllin, echinochrome, field stain, methylene blue, phthalocyanine, rhodamine 6G, riboflavin, and safranin, respectively. Methylene blue recorded the highest median lethal concentration (LC₅₀ = 127 ppm) followed by safranin, field stain, rhodamine 6G, phthalocyanine, echinochrome riboflavin, and chlorophyllin (LC₅₀ = 209, 251, 271, 303, 324, 332, and 362 ppm, respectively, 72 h PT). Their median lethal time, LT₅₀, values PT with 240 ppm were 45, 87, 96, 72, 129, 115, 131, and 137 h, respectively. The relative toxicities of the LC₅₀ values 72 h PT showed that chlorophyllin, echinochrome, field stain, methylene blue, phthalocyanine, rhodamine 6G, riboflavin, and safranin were 3.2, 3.6, 4.6, 9.1, 3.8, 4.3, 3.5, and 5.6 times, respectively, more effective than Phoxim. Methylene blue, safranin, and field stain showed a broad absorbance area indicating a large photoactivity and better phototoxicity and could be used as alternative agents to synthetic acaricides. Graphical Abstract

The leakage of sewage and agricultural drains has led to the contamination of freshwater branches with toxic heavy elements. This raises concerns about their toxic effects on aquatic ecosystems, especially on fish. Tilapia is regarded as an important protein source in Egypt and many other countries. The biophysical, nutritional, and histological aspects of water pollution in the El-Rahawy and Al-Qatta locations of the Nile on Nilotic tilapia muscle were evaluated by assessing the level of contamination of Nilotic tilapia fish. The current study showed that water of the Rosetta branch water was polluted with a very high level at El-Rahawy Drain discharge (RD) location, and with a high level at Al-Qatta (Q) location, while El-Rahawy (R) location was polluted with a lower level. The study traced the pollution effects on Tilapia (Nilotic) muscles in the previous locations. Bioaccumulation factor (BAF) showed a high value of all heavy metals in Tilapia muscle at the Q and R locations. Contrary to what was expected, discharge (RD) location contamination caused BAF increment of heavy metals in Tilapia muscles at upstream R location. All these results were compared with measured dielectric parameters of Tilapia muscle samples in the frequency range (0.02-1000) kHz. There was an increase in conductivity (σ_ac), dielectric constant (ε'), dielectric loss (ε″), penetration depth (dp), and dissipated power (PD) values of Tilapia muscle, with increasing pollution level. The values of permittivity at low and high frequencies (ε'_s & ε'_∞) for Tilapia muscle decreased by increasing pollution. Finally, the variation of these parameters, based on that proportionality relationship, can be considered as a physical indicator for fish contamination affected by their environment pollution, although these parameters need further studies in a controlled (qualitatively and quantitatively) polluted media.

Hydroxyapatite Ca₁₀[PO₄]₆[OH] is a biocompatible widely used in medicine and dentistry. Its applications depend greatly upon lattice substitution of Calcium sites in its structure by varies cations such as Na, Mg, Sr, Ag etc. Chromium plays an important role in reducing blood sugar level and improving insulin ability to convert glucose in cells to gain energy. In this paper we studied the effect of doping hydroxyapatite with chromium ions on its crystal dielectric properties. Pure hydroxyapatite and chromium loaded hydroxyapatite of chromium concentrations of 0.5, 1.0, 2.0, and 3.0 wt % forming samples S1, S2, S3 and S4 respectively were prepared by wet precipitation method. The dielectric parameters, permittivity ἐ, dielectric loss ἕ, conductivity σ, relaxation time t_s and dielectric modulus M’ and M’’ were calculated at frequency of 20 Hz to 10 MHz. Results showed increase of ἐ, and ἕ, values of chromium loaded samples compared to pure hydroxyapatite. The conductivity of the doped samples was increased with chromium concentration increase. The relaxation times (t_s) chromium loaded samples showed increase of t_s as chromium concentration increase. The dielectric properties showed that as chromium concentration increase, ἐ, ἕ, and σ of substance increase compared to the pure HA.

Mosquitoes are the primary vectors that transmit diseases affecting humans. Chemical interventions for mosquito management have caused harm to humans, beneficial organisms, and the environment. Hence, researchers are diverting their interest to comparatively safer botanicals. The tobacco plant ( Nicotiana tabacum L.) is known to contain nicotine and other diverse bioactive phytochemicals with insecticidal properties. The current study aims to repurpose nicotine-containing cigarette butt waste (CBW), a widespread environmental pollutant that poses ecological and economic challenges due to its persistent and toxic chemical components, as friendly insecticides. The study evaluated the methanol and aqueous extracts from tobacco leaves ( Nicotiana tabacum L.) and cigarette butts (CBs) of various brands against the larvae of Culex pipiens and Aedes aegypti under field and laboratory conditions and their effects on non-target organisms. Tobacco leaves methanol extracts exhibited higher larvicidal activity (98.0–100%, at 500 ppm) than aqueous extracts (96.0–100%, at 2000 ppm). The methanol extracts of Merit CBs (LC ₅₀ = 15.45 ppm) demonstrated greatest effectiveness against Cx. pipiens larvae, while the methanol extracts of Cleopatra CBs (LC ₅₀ = 25.71 ppm) were found to be more effective against Ae. aegypti 24 hours post-treatment. On the other hand, the aqueous extracts of LM cigarette butts (LC ₅₀ = 61.22 and 68.14 ppm) were recorded as most potent against Cx. pipiens and Ae. aegypti larvae than other CBs. Interestingly, the oviposition activity was higher and positive in CB-treated blackish color cups than that in control water. Field trial data showed 95% and 84% larval reduction with respective Merit CB and tobacco leaves methanol extracts 24 h post-treatment, with persistence for 6 and 3 days, respectively. GC-MS analyses showed a higher number of terpenes, flavonoids, and phenolic compounds in CB extracts. The 3-(1-methyl-2-pyrrolidinyl)-, (S)-, hexadecen-1-ol, phytol, and docosane were the main identified phytochemical compounds. Our findings demonstrate that tobacco and CBs extracts are effective larvicides and represent eco-friendly alternatives for mosquito control.