Alkali metals doped cycloparaphenylene nanohoops: Promising nonlinear optical materials with enhanced performance.

In the ongoing pursuit of novel and efficient NLO materials, the potential of alkali metal-doped {6}cycloparaphenylene ({6}CPP) and methylene bridged {6} cycloparaphenylene (MB{6}CPP) nanohoops as excellent NLO candidates has been explored. The geometric, electronic, linear, and nonlinear optical properties of designed systems have been investigated theoretically. All the nanohoops demonstrated thermodynamic stability, with remarkable interaction energies reaching up to -1.39 eV (-0.0511 au). Notably, the introduction of alkali metals led to a significant reduction in the HOMO-LUMO energy gaps, with values as low as 2.92 eV, compared to 6.80 eV and 6.06 eV for undoped {6}CPP and MB{6}CPP, respectively. Moreover, the alkali metal-doped nanohoops exhibited exceptional NLO response, with the K@r6-{6}CPP complex achieving the highest first hyperpolarizability of 56,221.7 × 10-30 esu. Additionally, the frequency-dependent first hyperpolarizability values are also computed at two commonly used wavelengths of 1550 nm and 1907 nm, respectively. These findings highlight the potential of designed nanohoops as promising candidates for advanced NLO materials with high-tech applications.

Photoswitchable nonlinear optical properties of azobenzene-based supramolecular complexes: insights from density functional theory.

Density functional theory (DFT) calculations were performed for a series of supramolecular assemblies containing azobenzene (Azo-X where X = I, Br and H) and alkoxystilbazole subunits to evaluate their electronic, linear and nonlinear optical properties. These assemblies are derivatives of azobenzene, obtained by the substitution of electron-withdrawing and electron-donating groups onto the molecular skeleton. The interaction energies (Eint) of all the designed supramolecular complexes (IA-IF, IIA-IIF and IIIA-IIIF) range from -1.0 kcal mol-1 to -7.7 kcal mol-1. The electronic properties of these hydrogen/halogen bond driven supramolecular assemblies such as vertical ionization energies (VIE), HOMO-LUMO energy gap (GH-L), excitation energies, density of states (DOS) and natural population (NPA) analyses were also computed. The non-covalent interaction index (NCI) and quantum theory of atoms in molecules (QTAIM) analyses were also performed to validate the nature of inter- and intra-molecular interactions in these complexes. A substantial enhancement in the first hyperpolarizability (ß0) values of the designed supramolecular complexes was observed, which is driven by the charge transfer from the pyridyl moiety of alkoxystilbazole to Azo-X. The highest ß0 value of 1.3 × 104 au was observed for the supramolecular complex of p-nitro substituted azobenzene with alkoxystilbazole (ID complex). Moreover, the results show that the substitution of electron-withdrawing groups on Azo-X can also bring larger ß0 values for such complexes. It was confirmed on a purely theoretical basis that both the types of noncovalent interactions present and the substituent group incorporated influence the nonlinear optical (NLO) response of the systems. Furthermore, the ß0 values of the E (trans) and Z (cis) forms were compared to demonstrate the two-way photoinduced switching mechanism.

Four new species in Leucoagaricus (Agaricaceae, Basidiomycota) from Asia.

The genus Leucoagaricus has been well studied in Europe. However, species diversity of Leucoagaricus in Asia remains poorly known, especially in the mountains of southwestern China, a hot spot for biodiversity. Based on morphological characters and molecular data, four new species are described, La. asiaticus, La. subcrystallifer, La. subpurpureolilacinus and La. truncatus. Detailed morphological descriptions, drawings of microstructures for novel taxa and comparisons with closely allied taxa are provided. Phylogenetic analyses inferred from internal transcribed spacer (ITS) and region 6-7 of the gene for the second largest subunit of RNA polymerase II (rpb2) sequences show that the novel taxa are nested within a well-supported clade jointly formed by members of Leucoagaricus section Rubrotincti and subgenus Sericeomyces.

Adulticidal Activity of Olea vera, Linum usitatissimum and Piper nigera against Anopheles stephensi and Aedes aegypti under Laboratory Conditions.

BACKGROUND: There are several plant extractions which are being used for mosquito control. The aim of this study was to evaluate the efficacy of Olea vera, Linum usitatissimum and Piper nigera against Anopheles stephensi and Aedes aegypti under laboratory conditions. METHODS: These tests were carried out using WHO recommended bioassay method for adult mosquitoes. RESULTS: The extracts from black pepper was more effective as adulticide with lowest LC(50) values (2.26% and 8.4%) against Aedes aegypti and Anopheles stephensi after 24 h of exposure while after 48h (1.56% and 5.11%) respectively. In terms of LC(90) value black pepper was best with (8.66% and 30.1%) against Ae. aegypti and An. stephensi after 24 h of exposure while after 48h (4.59% and 17.3%) respectively. In terms of LT(50) black pepper took 15 h to kill 50% tested population of Ae. aegypti while against An. stephensi it took more than 2 days. In terms of percentage mortality black pepper kill 84% of the population of Ae. aegypti and 44.75% of the An. stephensi population. CONCLUSION: Black pepper showed best results in term of LC(50), LC(90), LT(50) and percentage mortality against Ae. aegypti and An. stephensi. Our study suggested that the plant extracts have potential to kill adult mosquitoes, are environment friendly and can be used for the control of mosquitoes.

Determination of residues of sulphonamide in eggs and laying hens.

Eggs were collected from different areas of Faisalabad city. The quantity of sulphonamides was determined in yolk, white and whole egg and compared with the permissible limit 1 microg/ml for sulphadimethoxine available in literature. In another experiment, a group of hens were kept at a poultry farm after medicating them with darvisal liquid to see if the residues of sulphonamide pass into the eggs of poultry. The period of existence of residues was noted.

Pharmacokinetics and renal clearance of ampicillin in sheep.

Pharmacokinetics and renal clearance of ampicillin were investigated in 13 sheep, following one single oral dose of 750 mg. A peak concentration in plasma 0.38 +/- 0.04 microgram/ml (mean +/- SEM) was achieved 95.3 +/- 5.95 min after drug administration. Absorption half-life was 44.4 +/- 4.4 min. The area under the plasma concentration curve was 94.6 +/- 4.5 micrograms.hour.ml-1, while in the case of urine it was 370.5 +/- 28.3 micrograms.hour.ml-1. Biological half-life of ampicillin was 110 +/- 3 min, with an elimination rate constant of 0.0064 +/- 0.0002 min-1. The values for volume of distribution and total body clearance were 8.2 +/- 0.71/kg or 52.0 +/- 4.2 ml/kg/min, respectively. The priming and maintenance doses, using MIC as 0.05 microgram/ml, were suggested to be 8.8 or 8.4 mg/kg, respectively, at an 8-h interval. For MIC of 0.5 microgram/ml, this dose should be 10 times higher. Renal clearance of ampicillin seemed to involve active tubular secretion. Renal excretion indicated either extensive metabolism or excretion through routes other than kidneys.

Bioavailability, disposition kinetics and renal clearance of ampicillin following three routes of administration in sheep.

Bioavailability, disposition kinetics and renal clearance of ampicillin were investigated in 8 sheep following intravenous (i.v.), or intramuscular (i.m.) injection of 10 mg/kg or oral administration of 20 mg/kg dose. Peak of absorption was achieved in 26 +/- 9 min (mean +/- SD) after i.m. and 85 +/- 24 min after oral administration. The relative bioavailability of i.m. injected drug was 95 +/- 20 per cent compared to only 37 +/- 7 per cent following oral administration of double the dose. The disposition kinetics parameters of ampicillin were comparable in sheep with all three routes of drug administration. The renal clearance of ampicillin varied between 0.20 and 0.62 ml/min.kg while total body clearance was 50 to 64 ml/min.kg. The fractional urinary excretion of ampicillin in the first 8 hours after dosing was less than 1 per cent of the dose by all three routes.

Disposition kinetics of sulphadiazine in normal and diabetic rabbits.

Influence of alloxan induced metabolic disorder on the biodisposition kinetics of a weakly acidic drug sulphadiazine was investigated in rabbits. In 12 rabbits, mean +/- SD blood pH was 7.45 +/- 0.05, plasma glucose 123 +/- 10.6 mg%, plasma total lipids 336 +/- 124 mg% and plasma urea 36 +/- 6 mg%. After treatment with 150 mg/kg alloxan intravenously the blood pH was 7.20 +/- 0.06, plasma glucose 393 +/- 80.3, total lipids 532 +/- 181 and plasma urea was 48 +/- 10 mg%. Disposition kinetics showed that the plasma concentration of sulphadiazine was significantly (P less than 0.01) higher in normal condition when compared with that of metabolically altered. The zero-time plasma concentration was significantly (P less than 0.01) higher, apparent volume of distribution and total body clearance were significantly (P less than 0.01) lower in the normal than in the metabolically altered condition of rabbits. Elimination rate constant and the half-life did not reveal any significant difference in the normal and metabolically altered conditions. These studies demonstrate that the clinical biochemical conditions can influence the disposition kinetics and fate of weakly acid, and possibly of the weakly basic drugs. Therefore, the therapeutic standards of the drugs need be verified in the condition in which the drugs are to be employed clinically.

Preliminary phytochemical screening of four common plants of family caesalpiniaceae.

Preliminary phytochemical screening of Bauhinia variegata, Cassia fistula, Cassia tora and Tamarindus indica did not reveal alkaloids and unbound anthraquinones while glycosides as well as flavonoids were present in all the four species of the family caesalpiniaceae. Cardiac glycosides were absent only in C. tora and saponins were present only in T. indica, B. variegata and T. indica were devoid of bound anthraquinones while bound anthraquinones were present in C. fistula and C. tora. Paper chromatography revealed 6 spots in solvent system I, and 5 spots in solvent system 2, showing different Rf values. The per cent yield of crude glycosides was 3.18 in B. variegata, 4.03 in C. fistula, 4.45 in C. tora and 4.14 in T. indica.

Pharmacokinetics and urinary excretion of sulphadimidine in sheep during summer and winter.

Pharmacokinetics and urinary excretion of sulphadimidine were investigated in sheep during summer and winter seasons. Average minimum and maximum environmental temperature in the summer ranged from 22.6 to 40.2 degrees C and in winter from 4.5 to 21.1 degrees C. The determination of plasma volume, plasma protein and packed cell volume during summer and winter revealed a significant decrease in plasma volume and a significant increase in plasma protein in the summer indicative of haemoconcentration. Packed cell volume did not differ significantly between the seasons. The pharmacokinetics of sulphadimidine were determined following a single intravenous injection (100 mg/kg) in summer and winter. Zero time plasma concentration of the drug was higher during summer than in winter. The elimination half-life of the drug was similar in summer and winter, but the apparent volume of distribution was lower in summer. Likewise, total body clearance was significantly lower in summer. Based on these studies a satisfactory intravenous dosage regimen might consist of 86 and 100 mg/kg for priming and 78 and 88 mg/kg as maintenance doses during summer and winter, respectively, the doses being repeated at 12 hour intervals. Twenty four hours after sulphadimidine administration 90 and 73 per cent of the dose was excreted in urine during summer and winter, respectively. The drug was excreted mainly as free amine.