Setting up a system for first order results is straightforward. One can easily identify the major constituents in simple samples and obtain approximate concentrations. This is sufficient for some applications. However, second order effects are quite important for many applications. To obtain high accuracy, identify constituents with low concentrations, or operate on a wide variety of samples, s...

The prototropic exchange equilibria of two drugs, nizatidine (I) and ranitidine(II), and also of structurally related the N,N'-dimethyl-2-nitro-1,1-ethenediamine molecule (III) were investigated. From the changes in electronic spectra in media of various acidity several protonation constants were determined. For pK values were -0.82, 1.95, and 6.67; for ranitidine pK values were 1.95 and 8.13; ...

In the present work, leaves of mangrove plant, Derris trifoliata was successively extracted with methanol and for characterization, the leaf extract was subjected to thin layer chromatography and high performance thin layer chromatography. Different compounds were isolated and the structure of one particular compound was elucidated by NMR, IR, UV and GC-MS spectra.

Removal of cyclobutane pyrimidine dimers (CBPDs) in vivo from the DNA of UV-irradiated eight-leaf seedlings of Arabidopsis thaliana was rapid in the presence of visible light (half-life about 1 hour); removal of CBPDs in the dark, presumably via excision repair, was an order of magnitude slower. Extracts of plants contained significant photolyase in vitro, as assayed by restoration of transform...

Regional scale vegetation monitoring and yield forecasting require the estimation of biophysical parameters, such as Leaf Area Index (LAI), biomass and canopy water content (CWC). The CWC is also targeted for fire risk and drought monitoring. This work presents a methodology for jointly retrieval of Canopy Water Content (CWC) and Leaf Area Index (LAI) from coarse resolution satellite data. The ...

Abstract Little is known about the chlorophyll fluorescence spectra for high latitude plants. A FluoWat leaf clip was used to measure leaf-level reflectance and of leaves common plants examine general spectral characteristics these species. Fluorescence yield (Fyield) calculated as ratio emitted divided by absorbed radiation wavelengths from 400 nm up wavelength cut-off low pass filter (either ...

Objective: Vernonia amygdalina (V.  amygdalina) leaf is locally employed in the Southern region of Nigeria in the treatment of malari a infection. This study evaluated the in vivo antiplasmodial, antioxidant and immunomodulatory effect of ethanol extract of V.  amygdalina leaf. Materials and Methods: The active principles of the dried leaf were extracted with ethanol. For quality validation, ch...

In this work we present experimental and calculated two-dimensional electronic spectra for a 5,15-bisalkynyl porphyrin chromophore. The lowest energy electronic Qy transition couples mainly to a single 380 cm(-1) vibrational mode. The two-dimensional electronic spectra reveal diagonal and cross peaks which oscillate as a function of population time. We analyze both the amplitude and phase distr...

Aromatic constituents of cell walls limit the feeding value of forages, but information is lacking on the sites and types of these constituents that retard biodegradation. A series of cell types in stems and leaf blades of a normal (N) and a brown midrib (bmr) mutant line of pearl millet (Pennisetum glaucum (L) R Br) were analyzed by UV absorption microspectrophotometry from freeze-dried bulk w...