515 research outputs found
Differentiation of Mature Dopaminergic Neurons from Human Induced Pluripotent Stem Cells
No full textSampling hurdles : “Borderline Illegitimate” to legitimate data.
No full textIn this paper the author discusses how sampling access and recruitment problems encountered in an in-depth interview study heightened her sensitivity to “borderline illegitimate” data. The term illegitimate data usually refers to the data collected during a covert study, whereas “legitimate” data are collected during an overt study. Hence, data collected during any nonconsented period(s) of an overt study lie on the borderline of illegitimacy and legitimacy, and constitute what the author calls borderline illegitimate data. Such data need legitimization before use. The borderline illegitimate data were collected during the pre- and postinterview stages of her study as they explained how medical and ethnic cultures and sensitivity to racism as a topic combined to create sample recruitment difficulties of the study. The author later legitimized them by sharing them with the participants, guaranteeing anonymity, and asking their permission to use them
Human serum-derived α-synuclein auto-antibodies mediate NMDA receptor-dependent degeneration of CNS neurons
No full textAbstract
Background
Presence of autoantibodies against α-synuclein (α-syn AAb) in serum of the general population has been widely reported. That such peripheral factors may be involved in central nervous system pathophysiology was demonstrated by detection of immunoglobulins (IgGs) in cerebrospinal fluid and brain of Parkinson’s disease (PD) patients. Thus, blood-borne IgGs may reach the brain parenchyma through an impaired blood-brain barrier (BBB).
Findings
The present study aims to evaluate the patho-physiological impact of α-syn AAbs on primary brain cells, i.e., on spontaneously active neurons and on astrocytes. Exposure of neuron-astrocyte co-cultures to human serum containing α-syn AAbs mediated a dose-dependent reduction of spontaneous neuronal activity, and subsequent neurodegeneration. Removal specifically of α-syn AAbs from the serum prevented neurotoxicity, while purified, commercial antibodies against α-syn mimicked the neurodegenerative effect. Mechanistically, we found a strong calcium flux into neurons preceding α-syn AAbs-induced cell death, specifically through NMDA receptors. NMDA receptor antagonists prevented neurodegeneration upon treatment with α-syn (auto)antibodies. α-syn (auto)antibodies did not affect astrocyte survival. However, in presence of α-syn, astrocytes reacted to α-syn antibodies by secretion of the chemokine RANTES.
Conclusion
These findings provide a novel basis to explain how a combination of BBB impairment and infiltration of IgGs targeting synuclein may contribute to neurodegeneration in PD and argue for caution with α-syn immunization therapies for treatment of PD
The relevance of synuclein autoantibodies as a biomarker for Parkinson's disease
No full textSeveral studies have investigated if the levels of α-synuclein autoantibodies (α-syn AAb) differ in serum of Parkinson's disease (PD) patients and healthy subjects. Reproducible differences in their levels could serve as a biomarker for PD. The results of previous studies however remain inconclusive. With the largest sample size examined so far, we aimed to validate serum α-syn AAb levels as a biomarker for PD and investigated the presence of AAbs against other synucleins. We performed ELISA and immunoblots to determine synuclein AAb levels in the serum of 295 subjects comprising 157 PD patients from two independent cohorts, 46 healthy subjects, and 92 patients with other neurodegenerative disorders. Although serum α- and β-syn AAb levels were significantly reduced in patients with PD and other neurodegenerative disorders as compared to controls, the AAb levels displayed high inter-and intra-cohort variability. Furthermore, α-syn AAb levels showed no correlation to clinical parameters like age, disease duration, disease severity, and gender, that might also be directed against beta- and gamma-syn. In conclusion, serum synuclein AAb levels do allow the separation of PD from healthy subjects but not from other neurodegenerative disorders. Thus, synuclein AAbs cannot be regarded as a reliable biomarker for PD
Unpacking the impact of the TikTok ban on local content creators and the rise of Indianized social media apps.
No full textThis paper investigates the repercussions of the TikTok ban in 2020 and the subsequent migration of local content creators to alternative platforms, with a particular focus on the identity negotiation of the marginalized LGBTQIA+ community. The author positions this paper as an exploration of the displacement experienced by rural young queers in expressing their queerness following the ban. TikTok was a platform that transcended class barriers and provided an equal platform for socioeconomically diverse users. However, its ban led to the emergence of Indianized social media apps that have further segregated the classes. The author argues that this phenomenon requires academic attention because the rise of these Indian apps coincides with the overshadowing of right-wing populism. By exploring these complex dynamics, this paper contributes to the understanding of the impact of digital media on the social fabric of contemporary India.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/177335/1/15-Garg-Tiktok-Social Media and Society in India Proceedings-66-72-10.73027932.pdfSEL
Correction: Singh et al. An Experimental Investigation on the Material Removal Rate and Surface Roughness of a Hybrid Aluminum Metal Matrix Composite (Al6061/SiC/Gr). Metals 2021, 11, 1449
No full textHarish Kumar Garg was not included as an author in the published article [...
Leggett-Garg inequalities for quantum fluctuating work
No full textThis is the author accepted manuscript. The final version is available from MDPI via the DOI in this recordThe Leggett-Garg inequalities serve to test whether or not quantum correlations in time can be explained
within a classical macrorealistic framework. We apply this test to thermodynamics and derive a set of LeggettGarg
inequalities for the statistics of fluctuating work done on a quantum system unitarily driven in time. It
is shown that these inequalities can be violated in a driven two-level system, thereby demonstrating that there
exists no general macrorealistic description of quantum work. These violations are shown to emerge within the
standard Two-Projective-Measurement scheme as well as for alternative definitions of fluctuating work that are
based on weak measurement. Our results elucidate the influences of temporal correlations on work extraction
in the quantum regime and highlight a key difference between quantum and classical thermodynamics.HM is supported by EPSRC through a Doctoral
Training Grant. J.A. acknowledges support from EPSRC,
grant EP/M009165/1, and the Royal Society. This research
was supported by the COST network MP1209 “Thermodynamics
in the quantum regime”
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