Effect of Excitation and Vibrational Temperature on the Dissociation of Nitrogen Molecules in Ar-N2 Mixture RF Discharge

Non-equilibrium argon-nitrogen mixture plasma generated at 13.56 MHz is characterized by optical emission spectroscopy and Langmuir probe techniques. The excitation and vibrational temperature are studied as a function of argon percentage in the mixture, at 30-Pa filling pressure and input RF powers of 200 and 300 watt, to find out their role in dissociation of N₂ molecules. In this work, the excitation temperature is determined from Ar-I emission line intensities by using the simple Boltzmann plot method and is found to increase with argon mixing in nitrogen plasma. In similar fashion, the vibrational temperature of second positive system has been determined and is found to also have increasing trend with argon addition. The effect of excitation and vibrational temperature on the nitrogen molecular dissociation level is also monitored. It is observed that N/N ₂ ratio increases with increase in excitation and vibrational temperature and falls slightly at the end.     

Conservation laws via the partial Lagrangian and group invariant solutions for radial and two-dimensional free jets

The conservation laws for Prandtl’s boundary layer equations for an incompressible fluid governing the flow in radial and two-dimensional jets are investigated. For both radial and two-dimensional jets the partial Lagrangian method is used to derive conservation laws for the system of two differential equations for the velocity components. The Lie point symmetries are calculated for both cases and a symmetry is associated with the conserved vector that is used to establish the conserved quantity for the jet. This associated symmetry is then used to derive the group invariant solution for the system governing the flow in the free jet.     

Fluorine‐Free Synthesis of High‐Purity Ti3C2Tx (T=OH,O) via Alkali Treatment

MXenes, 2D compounds generated from layered bulk materials, have attracted significant attention in energy‐related fields. However, most syntheses involve HF, which is highly corrosive and harmful to lithium‐ion battery and supercapacitor performance. Here an alkali‐assisted hydrothermal method is used to prepare a MXene Ti₃C₂T_x (T=OH, O). This route is inspired from a Bayer process used in bauxite refining. The process is free of fluorine and yields multilayer Ti₃C₂T_x with ca. 92 wt % in purity (using 27.5 m NaOH, 270 °C). Without the F terminations, the resulting Ti₃C₂T_x film electrode (ca. 52 μm in thickness, ca. 1.63 g cm^?3 in density) is 314 F g^?1 via gravimetric capacitance at 2 mV s^?1 in 1 m H₂SO₄. This surpasses (by ca. 214 %) that of the multilayer Ti₃C₂T_x prepared via HF treatments. This fluorine‐free method also provides an alkali‐etching strategy for exploring new MXenes for which the interlayer amphoteric/acidic atoms from the pristine MAX phase must be removed.     

Anti-plasmodial and cholinesterase inhibiting activities of some constituents of Psorospermum glaberrimum

Glaberianthrone (1), a new bianthrone was isolated from the hexane extract of the stem bark of Psorospermum glaberrimum together with thirteen known compounds: 3-geranyloxyemodin anthrone (2), friedelan-3-one (3), 3-prenyloxyemodin anthrone (4), 3-geranyloxyemodin (5), 3-prenyloxyemodin (6), friedelan-3-ol (7), acetylvismione D (8), betulinic acid (9), 2-geranylemodin (10), bianthrone A2b (11), bianthrone 1a (12), emodin (13) and 2-prenylemodin (14). The structures of the isolated compounds were established by means of spectroscopic methods. The extracts and the isolated compounds were tested in vitro for their anti-plasmodial activity against Plasmodium falciparum (chloroquine resistant strain W2) and for their acetyl- and butyrylcholinesterase inhibitory properties. The n-hexane extract showed good anti-plasmodial activity against P. falciparum W2 strain, with IC(50) of 0.87 microg/ml. It also exhibited 65.5% and 98.2% of acetyl- and butyrylcholinesterase inhibition at 0.2 mg/ml, respectively. Compounds 2 and 8 showed the best potencies against P. falciparum W2 strain with IC(50) of 1.68 microM and 0.12 microM, (0.66 microg/ml and 0.054 microg/ml) respectively. All tested compounds showed good butyrylcholinesterase inhibition activities with compound 12 displaying the best potency (IC(50) 9.25+/-0.25 microM). All the tested compounds showed weak inhibitory activity against acetylcholinesterase.     

Effects on RCS of a perfect electromagnetic conductor sphere in the presence of anisotropic plasma layer

Effects on RCS of perfect electromagnetic conductor (PEMC) sphere by coating with anisotropic plasma layer are studied in this paper. The incident, scattered and transmitted electromagnetic fields are expanded in term of spherical vector wave functions using extended classical theory of scattering. Co and cross-polarized scattered field coefficients are obtained at the interface of free space-anisotropic plasma and at anisotropic plasma-PEMC sphere core by scattering matrices method. The presented analytical expressions are general for any perfect conducting sphere (PMC, PEC, or PEMC) with general anisotropic/isotropic material coatings that include plasma and metamaterials. The behavior of the forward and backscattered radar cross section of PEMC sphere with the variation of the magnetic field strength, incident frequency, plasma density, and effective collision frequency for the co-polarized and the cross polarized fields are investigated. It is also observed from the obtained results that anisotropic layer on PEMC sphere shows reciprocal behavior as compared to isotopic plasma layer on PEMC sphere. The comparisons of the numerical results of the presented analytical expressions with available results of some special cases show the correctness of the analysis.     

Hydromagnetic rotating flow of third grade fluid

This work investigates the flow of a third grade fluid in a rotating frame of reference. The fluid is incompressible and magnetohydrodynamic （MHD）. The flow is bounded between two porous plates, the lower of which is shrinking linearly. Mathematical modelling of the considered flow leads to a nonlinear problem. The solution of this nonlinear problem is computed by the homotopy analysis method （HAM）. Graphs are presented to demonstrate the effect of several emerging parameters, which clearly describe the flow characteristics.     

Anabasis articulata (Forssk.) Moq: A Good Source of Phytochemicals with Antibacterial,Antioxidant, and Antidiabetic Potential

Anabasis articulata is medicinally used to treat various diseases. In this study, A. articulata was initially subjected to extraction, and the resultant extracts were then evaluated for their antimicrobial, antioxidant, and antidiabetic potentials. After obtaining the methanolic extract, it was subjected to a silica gel column for separation, and fractions were collected at equal intervals. Out of the obtained fractions (most rich in bioactive compounds confirmed through HPLC), designated as A, B, C, and D as well hexane fraction, were subjected to GC-MS analysis, and a number of valuable bioactive compounds were identified from the chromatograms. The preliminary phytochemical tests were positive for the extracts where fraction A exhibited the highest total phenolic and flavonoid contents. The hexane fraction as antimicrobial agent was the most potent, followed by the crude extract, fraction A, and fraction D. DPPH and ABTS assays were used to estimate the free radical scavenging potential of the extracts. Fraction C was found to contain potent inhibitors of both the tested radicals, followed by fraction D. The potential antidiabetic extracts were determined using α-glucosidase and amylase as probe enzymes. The former was inhibited by crude extract, hexane, and A, B, C and D fractions to the extent of 85.32 ± 0.20, 61.14 ± 0.49, 62.15 ± 0.84, 78.51 ± 0.45, 72.57 ± 0.92 and 70.61 ± 0.91%, respectively, at the highest tested concentration of 1000 µg/mL with their IC₅₀ values 32, 180, 200, 60, 120 and 140 µg/mL correspondingly, whereas α-amylase was inhibited to the extent of 83.98 ± 0.21, 58.14 ± 0.75, 59.34 ± 0.89, 81.32 ± 0.09, 74.52 ± 0.13 and 72.51 ± 0.02% (IC₅₀ values; 34, 220, 240, 58, 180, and 200 µg/mL, respectively). The observed biological potentials might be due to high phenolic and flavonoid content as detected in the extracts. The A. articulata might thus be considered an efficient therapeutic candidate and could further be investigated for other biological potentials along with the isolation of pure responsible ingredients.     

Shape‐controlled synthesis of cerium oxide nanoparticles for efficient dye photodegradation and antibacterial activities

Herein, two‐shaped cerium oxide nanoparticles (NPs), that is, spherical and cubical, were synthesized through hydrothermal approach by tuning reaction temperatures. The morphology and structural and chemical composition of both samples were characterized by transmission electron microscopy (TEM), high‐resolution TEM (HRTEM), X‐ray diffraction (XRD), and X‐ray photoelectron spectroscopy (XPS), respectively. Both types of NPs were subjected to photodegradation of industrial dye, methylene blue, under dark, sunlight, and UV irradiation, and their recyclability and reusability were also assessed. Besides, the effect of pH, concentration of NPs, and dye on degradability was also analyzed. The cubical‐shaped NPs demonstrated superior degradation of ~70% under UV irradiation than the spherical ones (<50%). The antibacterial activities of both NPs were also examined, and cubical‐shaped NPs were found to exhibit superior antimicrobial potential (zone of inhibition [ZOI]: 25.75 ± 0.25, 18.83 ± 0.76, 15.75 ± 0.66, and 15.75 ± 0.25 mm) in comparison with the spherical ones (ZOI: 19.41 ± 0.94, 14.25 ± 0.66, 12.58 ± 1.01, and 9.91 ± 1.01 nm) for Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus respectively with reduced growth and viable count. This difference in performance may be attributed to the higher surface areas of cubical‐shaped NPs and higher content of oxygen vacancies. The results presented in this study suggest that cubical NPs are excellent candidates for treating industrial wastewater with greater reproducibility. Moreover, they can be used as active growth inhibitors against different microorganisms and thus can be extremely useful in developing medical devices and to design various antimicrobial systems.     

Synthesis of bis[benzyl‐N′‐hydrazinecarbodithioato‐κ2 N′,S]nickel(II) complex as a novel lead molecule for cancer treatment

A novel bis[benzyl‐N′‐hydrazinecarbodithioato‐κ² N′,S]nickel(II) complex was synthesized and characterized by means of various physical, chemical, and spectroscopic techniques. The X‐ray single crystal diffraction analysis indicated two independent close comparable bis‐chelated square planar complexes of trans‐configuration, where S‐benzyl dithiocarbazate (SBDTC) ligand is coordinated via N,S‐donor set. The complex is able to inhibit Ehrlich ascites carcinoma (EAC) cell proliferation by 51.81% and 75.75%, with 0.3 and 50 mg kg^?1 (dose adjusted) dose, respectively, administered intraperitoneally for five successive days in mice model. Apoptotic cell morphological changes were examined using optical and fluorescence microscopy techniques. Expression pattern of apoptosis regulatory genes in EAC cells treated with the synthesized nickel(II) complex for five consecutive days showed an increased expression of P⁵³, Bax, Cas‐8, Cas‐9, Cas‐3, Cyt‐c, and TNF‐α proapoptotic genes and decreased expression of antiapoptotic Bcl‐2 gene. The Ni(II) complex and Bleomycin (standard drug) were used in molecular docking coupled with molecular dynamics simulation studies with the aim to support the experimental results and to investigate the apoptotic effect towards the targeting apoptotic genes. Both experimental and computational studies reveal that the nickel(II) complex inhibits EAC cells growth successfully, suggesting a potential compound for cancer treatment.