Remarkable Increase In Rate Research Articles

Nanoparticles decorated carbon nanotubes as novel matrix: A comparative study of influences of immobilization on the catalytic properties of Lensculinarisβ-galactosidase (Lcβ-gal)

In the present study, Multiwalled carbon nanotubes (MWCNT) decorated with two different nanoparticles namely tungsten disulfide (WS2) and tin oxide (SnO2), nanocomposites (NCs) were synthesized via hydrothermal method. Spectroscopic studies showed that both synthesized NCs possess nearly same functional groups but MWCNT-SnO2 NCs are rich in O-functional group. Microscopic studies revealed that both NCs have different morphological microstructure. Lens culinaris β-galactosidase (Lcβ-gal) was immobilized using glutaraldehyde cross-linker resulted in immobilization efficiency of 91.5% and 88% with MWCNT-WS2 and MWCNT-SnO2 NCs, respectively. Remarkable increase in rate of hydrolysis of whey lactose has been observed with both NCs i.e. Lcβ-gal immobilized MWCNT-WS2 hydrolyzes the 97% whey lactose in 1.5 h while MWCNT-SnO2 showed maximum 92% of whey hydrolysis in 2 h at optimum conditions. Both nanobiocatalyst could serve as a promising candidates for dairy industries and would offer a potential platform for enzyme based biosensor fabrication.

Development, Characterization, and Pharmacodynamic Evaluation of Hydrochlorothiazide Loaded Self-Nanoemulsifying Drug Delivery Systems

The objective of the current work was to develop optimized self-nanoemulsifying drug delivery systems (SNEDDS) and evaluate their in vitro and in vivo performance. The research comprised various studies which includes solubility studies in various vehicles, pseudoternary phase diagram construction, and preparation and characterization of SNEDDS along with in vitro dissolution and in vivo pharmacodynamic profiling. Based on dissolution profile, a remarkable increase in rate of dissolution was observed in comparison with plain drug and marketed formulation. Optimized SNEDDS formulation was composed of Capmul MCM (19.17% w/w), Tween 80 (57.5% w/w), Transcutol P (12.7% w/w), and HCT (4.17% w/w). In vivo pharmacodynamic evaluation in Wistar rats showed considerable increase in pharmacological effect of HCT by SNEDDS formulation as compared with plain HCT.

Rapid Sonogashira cross-coupling of iodoferrocenes and the unexpected cyclo-oligomerization of 4-ethynylphenylthioacetate

A systematic study into the Sonogashira cross-coupling of 1,1'-diiodoferrocene (fcI2) confirms that the Pd(0)-P((t)Bu)3 system provides a remarkable rate increase over Pd(0)-(PPh3)2. Attempts to couple 4-ethynylphenylthioacetate (2) with fcI2 instead produced a novel cyclic trimer of the former, from syn addition of S-Ac across C≡C.

Intraspecific variations in growth, yield and photosynthesis of sorghum varieties to ambient UV (280–400 nm) radiation

A field study was conducted to investigate the impact of ambient solar UV on the various growth, physiological and yield parameters of four sorghum (Sorghum bicolor L.) varieties—Indore-12, Indore-26, CSV-23 and Indore-27 by excluding either UV-B (<315nm) or UV-A/B (<400nm) components of solar spectrum. Exclusion of UV significantly enhanced plant height, area and specific leaf weight of flag leaf, biomass accumulation, yield parameters and harvest index in all the sorghum varieties. Chlorophyll b was significantly enhanced and chlorophyll a increased to a lesser extent, UV-B absorbing substances and chlorophyll a/b ratio were significantly decreased by the exclusion of solar UV. The enhancement in the vegetative growth and yield by UV exclusion might be linked to the remarkable increase in rate of photosynthesis in sorghum varieties. The magnitude of the response was high in I-26 and I-27 as compared to CSV-23 and I-12 after exclusion of solar UV. All the varieties of sorghum had a negative cumulative stress response index (CSRI), the sensitivity of the sorghum varieties was in the following sequence I-12>CSV-23>I-26>I-27. Thus I-27 was the most sensitive and I-12 the least sensitive variety to present level of solar UV radiation. The differences in UV sensitivity identified among sorghum varieties might be useful in breeding programs for increased tolerance to UV-B radiation.

A study on improvement of solubility of rofecoxib and its effect on permeation of drug from topical formulations

Rofecoxib, a practically insoluble cox-2 selective nonsteroidal antiinflammatory agent was subjected to improvement in solubility by preparing its binary mixtures with β cyclodextrin using various methods such as physical mixing, co-grinding, kneading with aqueous methanol and co-evaporation from methanol-water mixture. Characterization of the resulting binary mixtures by differential scanning calorimetry and X-ray diffraction studies indicated partial amorphization of the drug in its binary mixtures. In vitro dissolution studies exhibited remarkable increase in rate and extent of dissolution of the drug from its complexes with β -cyclodextrin. Pure rofecoxib as well as its co-ground binary mixture were formulated as aqueous gels for topical application. In vitro skin permeation of rofecoxib from formulation containing rofecoxib-cyclodextrin complex was significantly higher (p<0.05) at 1, 2, 12, 18 and 24 hr as compared to formulation containing pure rofecoxib. This could be attributed to better solubility of binary mixture in the aqueous gel vehicle leading to greater concentration gradient between the vehicle and skin and hence higher flux of the drug.

Hydrolysis of adenosine triphosphate by conventional or microwave heating

The hydrolysis rate of adenosine-5'-triphosphate (ATP) has been reported to be 25 times greater during microwave heating than during conventional heating at comparable temperatures (100 to 105 °C). This remarkable rate increase was both attributed to and cited as evidence for a nonthermal microwave effect. Attempts to replicate those findings under carefully controlled microwave exposure conditions and with special attention being paid to accurate temperature measurements lead to the conclusion that the hydrolysis rate is related solely to temperature.

Hydrolysis of Adenosine Triphosphate by Conventional or Microwave Heating

ABSTRACTThe hydrolysis rate of adenosine-5'-triphosphate (ATP) has been reported to be 25 times greater during microwave heating than during conventional heating at comparable temperatures (100 to 105 °C). This remarkable rate increase was both attributed to and cited as evidence for a nonthermal microwave effect. Attempts to replicate those findings under carefully controlled microwave exposure conditions and with special attention being paid to accurate temperature measurements lead to the conclusion that the hydrolysis rate is related solely to temperature.

Thermolytic reactions of esters. Part 12. Steric versus polar effects in pyrolytic β-elimination of acetic acid from (tertiary) alkyl acetates

The vapour-phase pyrolysis of the crowded tertiary alkyl acetates AcOCMe2But(II) and AcOCMePri2(III) to give acetic acid and the appropriate alkene(s) has been studied. Rates of formation of alk-1-ene and of isobutene from t-butyl acetate were compared. On this basis steric acceleration in pyrolysis of AcOR, employing known steric parameters E′s from groups R, is quantitatively analysed. Although the steric effect can be quite substantial, the remarkable rate increase in the series AcOEt–AcOPri–AcOBut is largely due to a polar effect. A rationale is presented for the apparent inconsistency: the rate effect of α-alkylation in R is even larger than that in SN1-type solvolysis of RBr, suggesting a large charge separation AcO–, R+ in the transition state for concerted β-elimination, whereas the Hammett ρ value observed for pyrolysis of e.g. AcOCH(Me)C6H4Z is only a few percent of that associated with formation of benzylic carbenium ions.