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Abstract. The direct aerosol radiative forcing (DARF) has been estimated for the clear-sky conditions over Delhi from January 2006 to January 2007 using Santa Barbara DISORT Atmospheric Radiative Transfer model (SBDART) in the wavelength range 300-3000 nanometer. The single scattering albedo (SSA) and the asymmetry parameter used in this model were estimated using the Optical Properties of Aerosol and Cloud (OPAC) model. The annual average AOD observed at 500 nm was ∼0.86±0.42 with an average Angstrom exponent ∼0.68±0.35. The average monthly AOD throughout the year over Delhi was found to be in the range 0.56 to 1.22 with the Angstrom exponent in the range 0.38 to 0.96. A high monthly average BC concentration in the range 4-15 µg m −3 led to monthly average SSA in the range 0.90±0.4 to 0.74±0.3 during the year. Consequently, the monthly average clear-sky DARF at the surface was found to vary in the range −46±8 W m −2 to −110±20 W m −2 , at TOA in the range −1.4±0.4 to 21±2 W m −2 , whereas in the atmosphere it was in the range 46±9 W m −2 to 115±19 W m −2 throughout the year. As the dust concentration in the atmosphere was highest (May-June) the SSA showed an increase with wavelength however when dust concentration was low the SSA decreased with the wavelength.

The aerosol optical depth (AOD), Angstrom coefficients (α and β), and the second-order Angstrom exponent (α ) obtained byMicrotops-II sun photometer have been analyzed in the spectral range 0.34-0.87 µm over the urban polluted city of Delhi, India for the period 2007-2008, aiming at investigating the physical and optical properties of aerosols. The average values of AOD at 500 nm, α and β (in the range 340-870 nm) are found to be 0.78 ± 0.32, 0.78 ± 0.28, and 0.45 ± 0.21, respectively, for the entire period of observations. The AOD data show significant curvature in the lnτ versus lnλ relationship suggesting different dominant aerosol types depending on season. In order to analyze further the curvature effect and the relative dominance of aerosol size, α has been calculated in three wavelength bands, i.e., shorter (0.34-0.50 µm), longer (0.675-0.87 µm), and broad (0.34-0.87 µm) during four seasons, summer (April-June), monsoon (July-September), winter (October-January), and spring (February-March) accompanied with calculations of α , which quantifies the deviation of logarithmic behavior of AOD with lnλ. The α values are found to be positive and higher in the months of October-December and mostly negative in February and March, while close to zero values of α are found in April-August. These results indicate that winter season exhibits dominance of fine-mode aerosols while summer relatively higher concentration of coarse-mode particles. On the other hand, monsoon and spring seasons revealed the presence of mixed type, both fine-and coarse-mode aerosols over Delhi.

In the present study, sulforaphane (SFN)-loaded nanostructured lipid carriers (NLC) were developed and optimized for improved oral efficacy against cancer. The SFN-loaded NLC formulation was developed by melt emulsification ultrasonication technique and optimized by Box-Behnken statistical design. The optimized SFN-loaded NLC formulation composed of precirol ATO 5 (solid lipid) and vitamin E (liquid lipid) as lipid phase (3% w/v), poloxamer 188 (1%) and Tween 80 (1%) as surfactant. The mean particle size, polydispersity index, zeta potential, entrapment efficiency (%) and drug loading (%) of optimized SFN-loaded NLC formulation was observed to be 145.38 ± 4.46 nm, 0.181 ± 0.023, -25.12 ± 2.36 mV, 84.94 ± 3.82% and 14.82 ± 3.46%, respectively. In vitro drug release studies showed that the release of SFN from optimized NLC formulation was significantly higher (86.52 ± 5.48%) compared to SFN suspension (38.47 ± 5.52%) up to 24 h. Ex vivo gut permeation studies revealed a very good enhancement in permeation of drug present in the NLC compared to plain SFN solution and were further confirmed by CLSM. MTT assay in different cancer cell lines showed that the optimized SFN-loaded NLC formulation exhibited significantly improved (p < .05) cytotoxicity compared to free SFN solution. SFN-loaded NLC formulation showed significantly improved antioxidant activity compared to free SFN solution. Furthermore, pharmacokinetic study on albino Wistar rats showed 5.04-fold increase in relative oral bioavailability with NLC (p < .05) compared to SFN suspension. Therefore, NLC represents a great potential for improved efficacy of SFN after oral administration.

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