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Fulltext Development of simple designs of multitip probe diagnostic systems for RF plasma characterization

Naz MY, Shukrullah S, Ghaffar A, Rehman NU

ScientificWorldJournal, 2014;2014:279868.
PMID: 24683326 DOI: 10.1155/2014/279868

Multitip probes are very useful diagnostics for analyzing and controlling the physical phenomena occurring in low temperature discharge plasmas. However, DC biased probes often fail to perform well in processing plasmas. The objective of the work was to deduce simple designs of DC biased multitip probes for parametric study of radio frequency plasmas. For this purpose, symmetric double probe, asymmetric double probe, and symmetric triple probe diagnostic systems and their driving circuits were designed and tested in an inductively coupled plasma (ICP) generated by a 13.56 MHz radio frequency (RF) source. Using I-V characteristics of these probes, electron temperature, electron number density, and ion saturation current was measured as a function of input power and filling gas pressure. An increasing trend was noticed in electron temperature and electron number density for increasing input RF power whilst a decreasing trend was evident in these parameters when measured against filling gas pressure. In addition, the electron energy probability function (EEPF) was also studied by using an asymmetric double probe. These studies confirmed the non-Maxwellian nature of the EEPF and the presence of two groups of the energetic electrons at low filling gas pressures.
Fulltext Visible light induced photocatalytic degradation of norfloxacin using xC-TiO2

Adnan, Kalsoom, Zada FM, Sarwat, Soonmin H, Khan B, et al.

Heliyon, 2025 Jan 15;11(1):e41320.
PMID: 39831162 DOI: 10.1016/j.heliyon.2024.e41320

In recent years, antibiotic pollution has become a major environmental concern. The extensive production and widespread use of prescribed antibiotics have significantly impacted ecosystems. The main objective of the present study is to investigate the photocatalytic degradation of the antibiotic norfloxacin (NFX) under visible light. In this work photocatalysis of NFX was demonstrated under the source of visible radiation by using carbon dopped-titania (C-TiO 2 ) nanoparticles as catalyst prepared by a modified sol-gel method using n-hexane and benzene as carbon precursors. The synthesized samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDX) techniques. The effect of various parameters like initial concentration, catalyst dosage, irradiation time, pH, and inorganic ions were investigated on the photocatalysis of NFX. The XRD and SEM analysis exhibits that the synthesized C-TiO 2 nanoparticles were of anatase phase having spherical shape with a mean particle size of about 11-17 nm. The results shows that the best photocatalytic efficiency (74 % & 81 %) was achieved at pH = 8 in 150 min. The degradation of NFX follows pseudo-2nd -order kinetics, while favors Langmuir isotherm model. The inhibition effect of various inorganic ions on the photocatalysis of NFX was in the order of F⁻>SO4 2⁻>HCO3 ⁻>NO3 ⁻. The present study shows that C-TiO 2 is an optimistic and efficient catalyst for the photocatalysis of NFX antibiotics.
Fulltext Experimental and molecular modeling approach to optimize suitable polymers for fabrication of stable fluticasone nanoparticles with enhanced dissolution and antimicrobial activity

Ahmed S, Govender T, Khan I, Rehman NU, Ali W, Shah SMH, et al.

Drug Des Devel Ther, 2018;12:255-269.
PMID: 29440875 DOI: 10.2147/DDDT.S148912

Background and aim: The challenges with current antimicrobial drug therapy and resistance remain a significant global health threat. Nanodrug delivery systems are playing a crucial role in overcoming these challenges and open new avenues for effective antimicrobial therapy. While fluticasone (FLU), a poorly water-soluble corticosteroid, has been reported to have potential antimicrobial activity, approaches to optimize its dissolution profile and antimicrobial activity are lacking in the literature. This study aimed to combine an experimental study with molecular modeling to design stable FLU nanopolymeric particles with enhanced dissolution rates and antimicrobial activity.
Methods: Six different polymers were used to prepare FLU nanopolymeric particles: hydroxyl propyl methylcellulose (HPMC), poly (vinylpyrrolidone) (PVP), poly (vinyl alcohol) (PVA), ethyl cellulose (EC), Eudragit (EUD), and Pluronics®. A low-energy method, nanoprecipitation, was used to prepare the polymeric nanoparticles.
Results and conclusion: The combination of HPMC-PVP and EUD-PVP was found most effective to produce stable FLU nanoparticles, with particle sizes of 250 nm ±2.0 and 280 nm ±4.2 and polydispersity indices of 0.15 nm ±0.01 and 0.25 nm ±0.03, respectively. The molecular modeling studies endorsed the same results, showing highest polymer drug binding free energies for HPMC-PVP-FLU (-35.22 kcal/mol ±0.79) and EUD-PVP-FLU (-25.17 kcal/mol ±1.12). In addition, it was observed that Ethocel® favored a wrapping mechanism around the drug molecules rather than a linear conformation that was witnessed for other individual polymers. The stability studies conducted for 90 days demonstrated that HPMC-PVP-FLU nanoparticles stored at 2°C-8°C and 25°C were more stable. Crystallinity of the processed FLU nanoparticles was confirmed using differential scanning calorimetry, powder X-ray diffraction analysis and TEM. The Fourier transform infrared spectroscopy (FTIR) studies showed that there was no chemical interaction between the drug and chosen polymer system. The HPMC-PVP-FLU nanoparticles also showed enhanced dissolution rate (P<0.05) compared to the unprocessed counterpart. The in vitro antibacterial studies showed that HPMC-PVP-FLU nanoparticles displayed superior effect against gram-positive bacteria compared to the unprocessed FLU and positive control.
The vascular effects of peppermint (Mentha longifolia. L) on aorta in a mouse model: an ex-vivo and computational study

Alkharfy KM, Ahmad A, Almuaijel S, Bin Hashim A, Raish M, Jan BL, et al.

J Biomol Struct Dyn, 2024 Dec 11.
PMID: 39663630 DOI: 10.1080/07391102.2024.2439616

The present study examined the vascular effects of peppermint or mint (Mentha longifolia L.) using an abdominal aortic rings model. Concentration-response curves for mint oil were generated after precontracting isolated mouse aorta with phenylephrine. The effect of different receptor antagonists and ion channel or enzyme inhibitors on the vasorelaxant potential of mint oil were studied. Molecular docking studies were conducted using computational techniques to investigate the potential interactions between the bioactive constituents of mint oil and key vascular targets. The tension of aortic rings, which had been contracted by phenylephrine, relaxed as a function of the concentration of mint oil (0.0002-2 mg/mL). Pretreatment of the rings with the nitric oxide synthase inhibitor (L-NAME), a nonselective β-blocker (propranolol), and a muscarinic receptor blocker (atropine) didn't show significant resistance to the vasodilatory effects of the mint oil. The vasodilatory effects of mint oil were significantly diminished when the rings were pretreated with glibenclamide, an inhibitor of ATP-sensitive K+ channels. In addition, indomethacin, a cyclooxygenase (COX) inhibitor, did influence mint oil's tension in the preparations precontracted with phenylephrine. The present findings imply that ATP-sensitive K+ channels activation, blocking of Ca2+ channels, and inhibition of COX play a role in mediating the mint oil-induced vasorelaxation. Molecular docking studies of mint oil constituents showed that β-Elemene and Aromadendrene can interact with K+ and Ca2+ channels through various hydrophobic interactions with key amino acid residues. Additional work is needed to confirm the possible beneficial application of mint oil or its constituents in regulating the vascular tone.