13 research outputs found
"The fruits of independence": Satyajit Ray, Indian nationhood and the spectre of empire
Challenging the longstanding consensus that Satyajit Ray's work is largely free of ideological concerns and notable only for its humanistic richness, this article shows with reference to representations of British colonialism and Indian nationhood that Ray's films and stories are marked deeply and consistently by a distinctively Bengali variety of liberalism. Drawn from an ongoing biographical project, it commences with an overview of the nationalist milieu in which Ray grew up and emphasizes the preoccupation with colonialism and nationalism that marked his earliest unfilmed scripts. It then shows with case studies of Kanchanjangha (1962), Charulata (1964), First Class Kamra (First-Class Compartment, 1981), Pratidwandi (The Adversary, 1970), Shatranj ke Khilari (The Chess Players, 1977), Agantuk (The Stranger, 1991) and Robertsoner Ruby (Robertson's Ruby, 1992) how Ray's mature work continued to combine a strongly anti-colonial viewpoint with a shifting perspective on Indian nationhood and an unequivocal commitment to cultural cosmopolitanism. Analysing how Ray articulated his ideological positions through the quintessentially liberal device of complexly staged debates that were apparently free, but in fact closed by the scenarist/director on ideologically specific notes, this article concludes that Ray's reputation as an all-forgiving, âeverybody-has-his-reasonsâ humanist is based on simplistic or even tendentious readings of his work
The MaPLE device: A linear machine for laboratory studies of the magnetized plasma physics phenomena
A human placental extract: in vivo and in vitro assessments of its melanocyte growth and pigment-inducing activities
Background: The authenticity of various prototype human placental extracts with biological activity, such as that inducing vitiligo repigmentation, is under serious criticism, mainly due to a lack of demonstration at the cellular level. Considering the present worldwide scenario with regard to the occurrence and treatment of vitiligo, a thorough scientific exploration of such extracts should be undertaken. Method: One such prototype placental preparation was prepared, and was evaluated with regard to its melanogenic action in C57BL/6J mice in vivo and its mitogenic and melanogenic activity on B16F10 mouse melanoma cells and normal human melanocytes in vitro. The extract was applied topically to mice with age-induced prolonged telogenic phase of hair growth (grey body coat hair). Standard 3H-thymidine incorporation and spectrophotometric methods were followed to illustrate mitogenic and melanogenic effects at the cellular level. Results: The resurgence of blue skin, followed by shiny black hair, at the regions of application of the extract demonstrated the reversal of the age-induced prolonged telogenic phase of hair growth to the anagenic phase after topical application of the extract on C57BL/6J mice. Further support was obtained from histology where, at the extract-treated sites, the development of new melanogenic centers and hair follicles was observed. During in vitro studies, the vehicle-free extract constituents stimulated both mitogenesis and melanogenesis of B16F10 mouse melanoma cells in a concentration-dependent manner. The cell morphology and extent of melanogenesis also showed significant changes. In addition, two known melanocyte activity-modulating peptides, endothelin-1 (ET-1) and adrenocorticotropic hormone (ACTH), were determined in the extract, chiefly in the total lipid fraction, indicating their effective cutaneous permeation. Conclusions: The extract was found to be a potent mitogen in the in vitro condition and a potent melanogen in both the in vitro and in vivo situations. This strongly suggests its therapeutic potential for the repigmentation of vitiligo patches
Metal-Free Activation of Molecular Oxygen by Quaternary Ammonium-Based Ionic Liquid: A Detail Mechanistic Study
Most oxidation processes in common
organic synthesis
and chemical
biology require transition metal catalysts or metalloenzymes. Herein,
we report a detailed mechanistic study of a metal-free oxygen (O2) activation protocol on benzylamine/alcohols using simple
quaternary alkylammonium-based ionic liquids to produce products such
as amide, aldehyde, imine, and in some cases, even aromatized products.
NMR and various control experiments established the product formation
and reaction mechanism, which involved the conversion of molecular
oxygen into a hydroperoxyl radical via a proton-coupled electron transfer
process. Detection of hydrogen peroxide in the reaction medium using
colorimetric analysis supported the proposed mechanism of oxygen activation.
Furthermore, first-principles calculations using density functional
theory (DFT) revealed that reaction coordinates and transition state
spin densities have a unique spin conversion of triplet oxygen leading
to formation of singlet products via a minimum energy crossing point.
In addition to DFT, domain-based local pair natural orbital coupled
cluster, (DLPNOâCCSD(T)), and complete active space self-consistent
field, CASSCF(20,14) methods complemented the above findings. Partial
density of states analysis showed stabilization of Ï* orbital
of oxygen in the presence of ionic liquid, making it susceptible to
hydrogen abstraction in a mild, metal-free condition. Inductively
coupled plasma atomic emission spectroscopic (ICP-AES) analysis of
reactant and ionic liquids clearly showed the absence of any significant
transition metal contamination. The current results described the
origin of O2 activation within the context of molecular
orbital (MO) theory and opened up a new avenue for the use of ionic
liquids as inexpensive, multifunctional and high-performance alternative
to metal-based catalysts for O2 activation
Transcriptional activation of tyrosinase gene by human placental sphingolipid
The sphingolipids, a class of complex bioactive
lipids, are involved in diverse cellular functions such
as proliferation, differentiation, and apoptosis as well as
growth inhibition. Recently sphingosylphosphorylcholine
(SPC), sphingosine-1-phosphate (S1P), and C2-ceramide
(C2-Cer), sphingolipid containing acetic acid are emerging
as melanogenic regulators. A bioactive sphingolipid (PSL)
was isolated from hydroalcoholic extract of fresh term human
placenta and it induced melanogenesis in an in vitro
culture of mouse melanoma B16F10 cells. Tyrosinase, the
rate-limiting enzyme for melanogenesis, is required to be
upregulated for the increased melanin production. The expression
of tyrosinase, both at protein as well as mRNA
level, was higher in the PSL treated B16F10 cells as evidenced
by Western blot and RT-PCR analysis. Actinomycin
D and cycloheximide, inhibitors of transcription and translation,
respectively, inhibited PSL-induced tyrosinase activity
and its protein expression showing decrease in melanogenesis,
correspondingly. The activity of GFP coupled tyrosinase
promoter was upregulated in transfected B16F10 cells after
treating with PSL as determined by fluorescence microscopy,
fluorometric analysis, and Western blot. These results, thus,
suggested that PSL upregulated tyrosinase gene expression
at transcription level through promoter activation to show
increased melanogenesis. Therefore, PSL as an inducer of
melanogenesis might account for the recovery of pigment in depigmentation disorder