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Comparison of the self-assembly and conformations of glucose- and galactose-based glycopyranosides in dilute aqueous solution
No full textA series of glycolipids (glycopyranosides) was prepared by coupling glucosamine or galactosamine (at the C2 position) with myristic (tetradecanoic) or palmitic (hexadecanoic) acid. The conformation and self-assembly were examined in aqueous solutions containing 10% methanol. Circular dichroism and FTIR spectroscopy reveal notable differences in the chiral ordering and conformation comparing analogues with glucose and galactose “headgroups”. A glucose derivative (to palmitic acid) was also prepared with a different (C1-) substitution position of the lipid chain, and this was found to significantly influence chiral ordering and conformation. The self-assembly of the glycolipids was examined using cryogenic-transmission electron microscopy (cryo-TEM) and small-angle X-ray scattering (SAXS), which reveals lamellar structures, unilamellar for the glucose-based glycolipids, but multilamellar for the galactose-based analogues. Thus, the conformation and self-assembly of the molecules are very distinct, even though the glucose and galactose homologues have very similar structures, differing only in the orientation of a single hydroxyl group as epimers. These findings were rationalized with information from atomistic molecular dynamics (MD) simulations, which showed large differences in hydrogen-bonding density for glucose and galactose derivatives. The number of hydrogen bonds within interdigitated bilayers was much higher for the glucose variants, leading to stabilized unilamellar structures. The unexpectedly large differences in conformation and self-assembly of glycolipids bearing epimer monosaccharides may influence their properties and bioactivities
Strange pause after a decisive victory: revisiting the geopolitical dimension of November offensive during Bangladesh's Liberation War
Get PDFThe coordinated offensive of 21 November 1971 marked India’s first
overt military intervention inside the East Pakistan, in support of the ongoing
Liberation War of Bangladesh. Following the November offensive, Bangladeshi
forces intensified their fight against Pakistani forces; however, India took a ‘strange’
pause till 03 December. This article explores the geopolitical significance of the
November Offensive. It explains why India took the odd pause, how Pakistan
reacted to it, and how significant was the November offensive from Bangladesh’s
perspective. Exploring the archival records of the United Nations, Indian Lok
Sabaha and Bangladesh Liberation War, the article argues that India opted for the
odd pause to secure international legitimacy and relegated her November offensive
in the East as an insignificant prelude. Pakistan’s reaction-a pre-emptive air strike on
Indian airfields in the Western Sector-transformed the Liberation War into an IndoPak war and exposed her as an initiator and aggressor. Unlike India, the November
offensive was not a ‘prelude’ for Bangladesh but a continuation of the war and a
merger of the two Forces; it exposed the wartime government to the geopolitics of
an internationalised civil war. Consequently, the first Operational Directive issued
by the Commander-in-Chief of Bangladesh Forces on 22 November, placed the
two Forces under a unified command and, more importantly, lending a layer of
legitimacy for both Forces while retaining the political authority and ownership of the
War. Bangladesh and India were guided by geopolitical considerations-exemplifying
Clausewitz’s maxim that war is an instrument of (geo)politics by other means
Effects of early-life malnutrition and iron deficiency anaemia on growth and development using a piglet model for human infants
No full textChildhood malnutrition and iron deficiency anemia (IDA) remain significant global health
challenges, particularly in low-resource settings, and can lead to life-long health
implications. Malnutrition appears to contribute to the development of environmental
enteric dysfunction (EED) resulting in nearly 25% of the world's children aged <5 years
having stunted growth. EED is commonly defined as an acquired subclinical disorder of
the small intestine, although etiology is unknown. Iron deficiency (ID) is the most prevalent
cause of global micronutrient malnutrition affecting 273 million children globally. These
conditions both appear to hinder immune function and gut health, but the lack of reliable
animal models, especially during the neonatal period, means there is little understanding
of the mechanisms involved. Piglets are valuable models for human infants since they
share many physiological characteristics. In addition, their precocial nature permits early
separation from maternal interference so their environment and nutrition can be tightly
controlled. Furthermore, if left untreated with iron, piglets will reliably develop IDA in the
first weeks of life, and characteristics of EED are observed in early and abruptly weaned
piglets, although the gut recovers within 2 weeks. Oral iron supplementation is the most
common strategy used worldwide to prevent and treat IDA. However, oral iron is
associated with detrimental side effects including diarrhoea and increased risk of
infectious diseases, although there is limited mechanistic understanding in this area. The
aims of this PhD were firstly to explore the effects of global malnutrition following early,
abrupt weaning, and secondly to explore IDA and different forms of iron supplementation
on growth and immune system development during both the neonatal and post-weaning
phase of growth, all using piglet models for human infants. To generate a model for EED
(Chapter 2), twelve 21d old piglets were early and abruptly weaned before being litter-matched into 2 treatment groups (n=6): control (adequate diet) and EED (subsistence
diet), To explore the effects of IDA and different forms of iron supplementation during the
neonatal phase (Chapter 3), twenty-four 1d old piglets were litter-matched into 4
treatment groups (n=6):IDA (no iron); control (intramuscular iron, 200 mgs Fe); oral iron
(150 mg/kg feed); oral and IM iron (excess iron). To determine the effects of low and high
oral iron supplementation post-weaning (Chapter 4), twelve 25-day old piglets, which all
received an IM injection of iron at 1 day old, were litter-matched into 2 treatment groups
(n=6): high iron (69.4 mg/kg feed +150 mg/kg feed); low iron (69.4 mg/kg feed). Piglet
growth and indicators of iron status were monitored throughout and fluorescence
immunohistology was used to quantify the expression of proteins associated with
intestinal barrier function and mucosal immune development. The results showed that
following abrupt and early weaning, a subsistence-type diet-maintained characteristics of
EED, including reduced barrier function and increased infiltration of immune-associated
cells all along the intestinal tract, consistent with the generation of a piglet model for EED
in infants. Neonatal IDA was associated with severely impeded immune development
along with increased potential to absorb luminal iron. While oral iron supplementation
prevented the development of neonatal IDA, it was associated with increased potential for
antigen presentation and immune-associated protein expression at several intestinal
locations. Finally, we showed that there were no benefits of high levels of oral iron
supplementation at weaning on piglet growth or iron status, but this treatment did reduce
intestinal barrier function. Our findings provide novel insight into the molecular effects of
EED, IDA and oral iron supplementation during early-life in an animal model which closely
reflects human infants, thus increasing translational potential. The results suggest that
caution should be taken when designing iron supplementation strategies to prevent the
development of IDA since over-supplementation is not only unbeneficial but appears to
have detrimental effects on gut health
Making political philosophy public: the role of empirical inquiry
No full textThe drive for greater public engagement and the turn to social science: each is an important and welcome movement in contemporary political philosophy. However, the relationship between these two boundary-crossing endeavours is not simple or obvious. I suggest that political philosophers have sometimes been too quick to assume that empirically-sensitivity and publicness go together; and I identify some ways in which these features can diverge and even compete. More positively, I go on to outline a modestly public role for political philosophy that is facilitated by in-depth engagement with diverse forms of social scientific evidence
Cross-linguistic asymmetries in language production and code-switching patterns in bilingual aphasia
No full textThis study investigates the underlying causes of cross-linguistic asymmetries in noun and verb production in a Hindi-English bilingual with severe Broca’s aphasia (RZ), focusing on the influence of task demands, morphological richness, and code-switching. We compared RZ’s performance on narrative and single word production tasks (noun naming, verb naming, repetition) with that of a non-brain-damaged bilingual control (BC) as well as analysed the frequency and type of code-switching to explore how these patterns reflect aphasic impairments in typologically distinct languages. RZ exhibited features of agrammatism in both languages, with more pronounced deficits in English. A clear grammatical class asymmetry emerged: RZ produced more verbs than nouns in Hindi, likely supported by Hindi’s rich morphological system, while English showed the opposite pattern, reflecting its limited morphological complexity. Task effects were evident, narratives elicited more verbs in Hindi, while naming tasks showed comparable noun-verb production. In English, consistent noun–verb asymmetries across tasks indicated persistent verb retrieval difficulties. Code-switching analysis revealed that RZ engaged in frequent but rigid switching, limited to English noun insertions within a Hindi matrix. This structured pattern, including the use of bilingual compound verbs, suggests a compensatory strategy to overcome a lexico-semantic deficit in Hindi and morphosyntactic challenges in English. These findings underscore the importance of language typology and task demands in shaping aphasic symptomatology in bilinguals