Remarks on the radiative transfer approach to scattering of electromagnetic waves in layered random media

The radiative transfer (RT) approach is widely used in applications involving scattering from layered random media with rough interfaces. Although it has been successful in several applications in various disciplines it is well known that this approach involves certain approximations. In this paper these assumptions and approximations are reexamined. To enable this a statistical wave approach is employed to this problem and the governing equations for the first and second moments of the wave functions are derived. A transition is hence made to arrive at a system of equations corresponding to that of the RT approach. It is hence found that more conditions are implicitly involved in the RT approach than generally believed to be sufficient.     

Chemical composition and antibacterial activity of essential oil from Salvia mukerjeei

The composition of steam volatile oil from aerial parts of Salvia mukerjeei Bennet & Raizada (Lamiaceae) was analyzed by capillary GC and GC-MS. The oil was rich in sesquiterpene hydrocarbons (67.3%). Among 71 identified constituents representing 91.7% of the oil, beta-caryophyllene (28.7%), gamma-muurolene (15.5%) and dehydro-aromadendrane (9.5%), were the principal constituents. The oil was tested against ten bacterial strains and was active against Enterococcus faecalis, Erwinia chrysanthemi and Agrobacterium tumefaciens.     

Excess Molar Volumes,Viscosity Deviations and Isentropic Compressibility of Binary Mixtures Containing 1,3-Dioxolane and Monoalcohols at 303.15 K

The excess molar volume (V ^E), viscosity deviations (Δη) and Gibbs excess energy of activation for viscous flow (G^∗E) have been investigated from density (ρ) and viscosity (η) measurements of eight binary mixtures of 1,3-dioxolane with methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, and i-amyl alcohol over the entire range of mole fractions at 303.15 K. The viscosity data have been correlated with the Grunberg and Nissan equation. Furthermore, excess isentropic compressibilities (K_S^E) have been calculated from ultrasonic speed measurements of these binary mixtures at 303.15 K. The deviations have been fitted by a Redlich–Kister equation and the results are discussed in terms of molecular interactions and structural effects. The excess properties are found to be either negative or positive depending on the molecular interactions and the nature of the liquid mixtures. The systems studied exhibit very strong cross association through hydrogen bonding.     

Complex amphiphilic networks derived from diamine‐terminated poly(ethylene glycol) and benzylic chloride‐functionalized hyperbranched fluoropolymers

Amphiphilic copolymer networks were prepared from hyperbranched fluoropolymer (HBFP*, M_n = 38 kDa, by atom transfer radical‐self condensing vinyl copolymerization) and linear diamine‐terminated poly(ethylene glycol) (DA‐PEG, M_n = 1,630 Da). Model studies found that the crosslinking mechanism occurred at ambient temperature as a result of reaction between DA‐PEG and the benzylic chlorides of HBFP*. These networks underwent covalent attachment to glass microscope slides derivatized with 3‐aminopropyltriethoxysilane, whereupon gel percent studies at various weight percentages of DA‐PEG to HBFP* found that curing could be achieved at lower temperatures and shortened time periods relative to the previously reported parent HBFP–PEG system. Thermogravimetric analysis revealed that the crosslinked materials gave no evident mass loss up to 250 °C. Differential scanning calorimetry of the complex amphiphilic networks showed a suppressed glass transition temperature, relative to that observed for neat HBFP*, and multiple melting DA‐PEG endotherm(s) near 30 °C. The films possessed a topographically‐complex surface with features that increased in tandem with an increase in the ratio of DA‐PEG to HBFP*, as detected by atomic force microscopy and quantified by increased rms roughness values. Internal reflection infrared imaging revealed a heterogeneous surface composition and confirmed that the domain sizes increased as the weight percent of DA‐PEG increased. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4782–4794, 2006     

Kinetics and mechanism of acid catalysed dissociation of some octahedral complexes of cobalt(III) and chromium(III)

Summary The kinetics of dissociation of glycinepentaamminecobalt(III) and tetraaquomonoacetylacetonatochrormium(III) ions in moderately strong perchloric acid media have been investigated spectrophotometrically. From the dependence of the rate on various acidity functions and the observed isokinetic and free energy relationships, both the complexes appear to react by an associative process involving interaction of the conjugate acid form of the substrate complex and H₃O⁺.     

Number of points on certain hyperelliptic curves defined over finite fields

For odd primes p and l such that the order of p modulo l is even, we determine explicitly the Jacobsthal sums _l(v), ψ_l(v), and ψ_2l(v), and the Jacobsthal–Whiteman sums and , over finite fields F_q such that . These results are obtained only in terms of q and l. We apply these results pertaining to the Jacobsthal sums, to determine, for each integer n1, the exact number of F_qⁿ-rational points on the projective hyperelliptic curves aY²Z^e−2=bX^e+cZ^e (abc≠0) (for e=l,2l), and aY²Z^l−1=X(bX^l+cZ^l) (abc≠0), defined over such finite fields F_q. As a consequence, we obtain the exact form of the ζ-functions for these three classes of curves defined over F_q, as rational functions in the variable t, for all distinct cases that arise for the coefficients a,b,c. Further, we determine the exact cases for the coefficients a,b,c, for each class of curves, for which the corresponding non-singular models are maximal (or minimal) over F_q.     

A rapid field detection method for arsenic in drinking water.

In this study, a rapid colorimetric method for arsenic detection was developed. Different reagents containing magnesium turnings in combination with a series of acids were tested for arsine generation. The arsine was then allowed to react with auric chloride on Whatman filter paper No. 3, which in turn changed color. The detection time and detection limit were measured for each acid. Oxalic acid was found to be the most appropriate acid among all the acids used for detection in this study. It took 10 min to detect 10 ppb arsenic concentration and only 1 min to detect concentrations higher than 50 ppb. This method thus reduced the detection time for arsenic and has the potential to develop better field kit.     

Tailoring nanocarriers for intracellular protein delivery

Proteins play a crucial role in life, taking part in all vital processes in the body. In the past decade, there was increasing interest in delivering active forms of proteins to specific cells and organs. Intracellular protein delivery holds enormous promise for biological and medical applications, including cancer therapy, vaccination, regenerative medicine, treatment for loss-of-function genetic diseases and imaging. This tutorial review surveys recent developments in intracellular protein delivery using various nanocarriers. Methods such as lipid-mediated colloidal systems, polymeric nanocarriers, inorganic systems and protein-mediated carriers are reviewed. Advantages and limitations of current strategies, as well as future opportunities and challenges are also discussed.