Pan-Africanism: a contorted delirium or a pseudonationalist paradigm? Revivalist critique

This essaic-article goes against established conventions that there is anything ethno-cultural (and hence national) about the so-called African tribes. Drawing largely from the culture history of precolonial/prepolitical Africans—that is, the Bantu/Cushitic-Ethiopians (Azanians)—the author has demonstrated vividly that far from being distinct ethno-culture national communities, the so-called tribes of African states are better considered subculture groups, whose regional culture practices erstwhile paid tribute to their nation’s main culture center in Karnak. For example, using the culture symbols and practices of some local groups and linking them to the predynastic and dynastic Pharaonic periods, I argued that there is compelling evidence against qualifying Africa’s tribes as distinct ethno-culture national entities. In genuine culture context, I stressed that the Ritual of Resurrection and its twin culture process of the mummification of deceased indigenous Pharaohs tend to suggest that the object of the Bantu/Cushitic-Ethiopians national culture was life (in its eternal manifestation) and then resurrection later, and that there are recurring (culturally sanctioned) ethical examples among the culture custodians of these subculture groups that generally pay tribute to the overarching culture norm. Furthermore, the fact that the Ritual of Resurrection began in the Delta region and ended at the Sources of the Nile, where the spirit of the deceased indigenous Pharaohs was introduced into the spiritual world of their ancestors, contradicts conventional perceptions that ancient Egypt was a distinct national community isolated from precolonial/prepolitical Africa/Azania

Differentiation of human adipose-derived stem cells into neuron/motoneuron-like cells for cell replacement therapy of spinal cord injury

Human adipose-derived stem cells (hADSCs) are increasingly presumed to be a prospective stem cell source for cell replacement therapy in various degenerative and/or traumatic diseases. The potential of trans-differentiating hADSCs into motor neuron cells indisputably provides an alternative way for spinal cord injury (SCI) treatment. In the present study, a stepwise and efficient hADSC trans-differentiation protocol with retinoic acid (RA), sonic hedgehog (SHH), and neurotrophic factors were developed. With this protocol hADSCs could be converted into electrophysiologically active motoneuron-like cells (hADSC-MNs), which expressed both a cohort of pan neuronal markers and motor neuron specific markers. Moreover, after being primed for neuronal differentiation with RA/SHH, hADSCs were transplanted into SCI mouse model and they survived, migrated, and integrated into injured site and led to partial functional recovery of SCI mice. When ablating the transplanted hADSC-MNs harboring HSV-TK-mCherry overexpression system with antivirial Ganciclovir (GCV), functional relapse was detected by motor-evoked potential (MEP) and BMS assays, implying that transplanted hADSC-MNs participated in rebuilding the neural circuits, which was further confirmed by retrograde neuronal tracing system (WGA). GFP-labeled hADSC-MNs were subjected to whole-cell patch-clamp recording in acute spinal cord slice preparation and both action potentials and synaptic activities were recorded, which further confirmed that those pre-conditioned hADSCs indeed became functionally active neurons in vivo. As well, transplanted hADSC-MNs largely prevented the formation of injury-induced cavities and exerted obvious immune-suppression effect as revealed by preventing astrocyte reactivation and favoring the secretion of a spectrum of anti-inflammatory cytokines and chemokines. Our work suggests that hADSCs can be readily transformed into MNs in vitro, and stay viable in spinal cord of the SCI mouse and exert multi-therapeutic effects by rebuilding the broken circuitry and optimizing the microenvironment through immunosuppression

Presynaptic action of adenosine on a 4-aminopyridine-sensitive current in the rat carotid body

Plasma adenosine concentration increases during hypoxia to a level that excites carotid body chemoreceptors by an undetermined mechanism. We have examined this further by determining the electrophysiological responses to exogenous adenosine of sinus nerve chemoafferents in vitro and of whole-cell currents in isolated type I cells.Steady-state, single-fibre chemoafferent discharge was increased approximately 5-fold above basal levels by 100 μM adenosine. This adenosine-stimulated discharge was reversibly and increasingly reduced by methoxyverapamil (D600, 100 μM), by application of nickel chloride (Ni2+, 2 mM) and by removal of extracellular Ca2+. These effects strongly suggest a presynaptic, excitatory action of adenosine on type I cells of the carotid body.Adenosine decreased whole-cell outward currents at membrane potentials above -40 mV in isolated type I cells recorded during superfusion with bicarbonate-buffered saline solution at 34–36 °C. This effect was reversible and concentration dependent with a maximal effect at 10 μM.The degree of current inhibition induced by 10 μM adenosine was voltage independent (45.39 ± 2.55% (mean ± s.e.m.) between −40 and +30 mV) and largely (∼75%), but not entirely, Ca2+ independent. 4-Aminopyridine (4-AP, 5 mM) decreased the amplitude of the control outward current by 80.60 ± 3.67% and abolished the effect of adenosine.Adenosine was without effect upon currents near the resting membrane potential of approximately −55 mV and did not induce depolarization in current-clamp experiments.We conclude that adenosine acts to inhibit a 4-AP-sensitive current in isolated type I cells of the rat carotid body and suggest that this mechanism contributes to the chemoexcitatory effect of adenosine in the whole carotid body

The rocky road to organics needs drying

AbstractHow simple abiotic organic compounds evolve toward more complex molecules of potentially prebiotic importance remains a missing key to establish where life possibly emerged. The limited variety of abiotic organics, their low concentrations and the possible pathways identified so far in hydrothermal fluids have long hampered a unifying theory of a hydrothermal origin for the emergence of life on Earth. Here we present an alternative road to abiotic organic synthesis and diversification in hydrothermal environments, which involves magmatic degassing and water-consuming mineral reactions occurring in mineral microcavities. This combination gathers key gases (N2, H2, CH4, CH3SH) and various polyaromatic materials associated with nanodiamonds and mineral products of olivine hydration (serpentinization). This endogenous assemblage results from re-speciation and drying of cooling C–O–S–H–N fluids entrapped below 600 °C–2 kbars in rocks forming the present-day oceanic lithosphere. Serpentinization dries out the system toward macromolecular carbon condensation, while olivine pods keep ingredients trapped until they are remobilized for further reactions at shallower levels. Results greatly extend our understanding of the forms of abiotic organic carbon available in hydrothermal environments and open new pathways for organic synthesis encompassing the role of minerals and drying. Such processes are expected in other planetary bodies wherever olivine-rich magmatic systems get cooled down and hydrated.</jats:p

The rocky road to organics needs drying

How complex organics form in a prebiotic world remains a missing key to establish where life emerged. The authors present a road to abiotic organic synthesis and diversification in hydrothermal contexts involving magmatism and rock hydration