A single-molecule method for measuring fluorophore labeling yields for the study of membrane protein oligomerization in membranes

Membrane proteins are often observed as higher-order oligomers, and in some cases in multiple stoichiometric forms, raising the question of whether dynamic oligomerization can be linked to modulation of function. To better understand this potential regulatory mechanism, there is an ongoing effort to quantify equilibrium reactions of membrane protein oligomerization directly in membranes. Single-molecule photobleaching analysis is particularly useful for this as it provides a binary readout of fluorophores attached to protein subunits at dilute conditions. However, any quantification of stoichiometry also critically requires knowing the probability that a subunit is fluorescently labeled. Since labeling uncertainty is often unavoidable, we developed an approach to estimate labeling yields using the photobleaching probability distribution of an intrinsic dimeric control. By iterative fitting of an experimental dimeric photobleaching probability distribution to an expected dimer model, we estimate the fluorophore labeling yields and find agreement with direct measurements of labeling of the purified protein by UV-VIS absorbance before reconstitution. Using this labeling prediction, similar estimation methods are applied to determine the dissociation constant of reactive CLC-ec1 dimerization constructs without prior knowledge of the fluorophore labeling yield. Finally, we estimate the operational range of subunit labeling yields that allows for discrimination of monomer and dimer populations across the reactive range of mole fraction densities. Thus, our study maps out a practical method for quantifying fluorophore labeling directly from single-molecule photobleaching data, improving the ability to quantify reactive membrane protein stoichiometry in membranes

Developing a model of conflict in virtual learning communities in the context of a democratic pedagogy

In this paper, we argue that in order to get a fuller understanding of the complexity of conflict in democratic pedagogies in online and blended learning settings, it is important to know not only how to manage or resolve it, but also how it is triggered and can be avoided. The emancipatory nature of democratic pedagogies fosters differences, and differences provide the basis for the emergence of conflict among learning community members. Much has been written on certain aspects of conflict, such as conflict management or effects of conflict; however, these studies are frequently disparate and fragmented. Conflict has a cyclical dynamic and the main purpose of this study has been to experimentally build an analytical model of this cyclical dynamic of conflict, drawing on both literature and research data.We believe that such a model might empower practitioners and designers of democratic pedagogies to embrace and work with the differences that lead to conflict, as a way to support collaborative learning and action. The model of conflict which emerged at the end of the study is supported by illustrative qualitative evidence and constituted in a diagrammatic depiction of analytic themes that illustrate the connections between these themes, and the values ascribed to them. The outcomes of this study have implications for developing learning strategies for distance and blended learnin

30 Years of Gender Inequality and Implications on Curriculum Design in Open and Distance Learning

Gender inequality is a pressing issue on a global scale, yet studies on this important issue have stayed on the margins of open and distance learning (ODL) literature. In this study, we critically analyse a batch of ODL literature that is focused on gender inequality in post-secondary and higher education contexts. We use Therborn’s social justice framework to inform and guide the study. This is a comprehensive social justice lens that sees inequality as “a life and death issue,” approaching empowerment as a central area of concern. Qualitative content analysis of 30 years of peer-reviewed literature reveals patriarchy and androcentrism as significant mechanisms that continue to produce gender inequality, in particular in women’s access to educational resources and formal learning opportunities. We highlight three themes that emerged in the content analysis: (1) ODL and equal opportunity; (2) Feminism and gender-sensitive curriculum design; and (3) Culturally relevant curriculum design. We critique views of access to technology-enabled education as an instrument for social justice, and provide a pedagogical model for an ODL curriculum centred on empowerment and agency, two concepts closely linked to existential inequality. We argue that such a curriculum is public service and requires a model of education that is based on participation and co-construction, and lies at the intersection of critical, feminist, and culturally relevant pedagogical practices

Linked CSF reduction of phosphorylated tau and IL-8 in HIV associated neurocognitive disorder.

HIV-associated neurocognitive disorder (HAND) is a common condition in both developed and developing nations, but its cause is largely unknown. Previous research has inconsistently linked Alzheimer's disease (AD), viral burden, and inflammation to the onset of HAND in HIV-infected individuals. Here we simultaneously measured cerebrospinal fluid (CSF) levels of established amyloid and tau biomarkers for AD, viral copy numbers, and six key cytokines in 41 HIV-infected individuals off combination anti-retroviral therapy (14 with HAND) who underwent detailed clinical and neuropsychological characterization, and compared their CSF patterns with those from young healthy subjects, older healthy subjects with normal cognition, and older people with AD. HAND was associated with the lowest CSF levels of phosphorylated tau (p-Tau181) after accounting for age and race. We also found very high CSF levels of the pro-inflammatory interferon gamma-induced protein 10 (IP-10/CXCL10) in HIV regardless of cognition, but elevated CSF interleukin 8 (IL-8/CXCL8) only in HIV-NC but not HAND. Eleven HIV-infected subjects underwent repeat CSF collection six months later and showed strongly correlated longitudinal changes in p-Tau181 and IL-8 levels (R = 0.841). These data suggest reduced IL-8 relative to IP-10 and reduced p-Tau181 to characterize HAND

Chemerin as a marker of subclinical cardiac involvement in psoriatic patients

Background: Chemerin has been associated with psoriasis and inflammation, but there are no studies demonstrating an association between chemerin and subclinical cardiac involvement in psoriatic patients. Therefore, the present study aimed to evaluate whether psoriatic patients with increased epicardial fat tissue, impaired flow-mediated dilatation, and diastolic dysfunction have higher serum chemerin levels than a healthy control group. Methods: The study included 60 psoriatic patients and 32 healthy controls. Echocardiographic parameters, epicardial fat tissue, flow-mediated dilatation, and chemerin levels were recorded for both groups. Results: The serum levels of chemerin in the psoriatic patients were significantly higher than in the control group. The diastolic function parameters, including isovolumic contraction and relaxation time, E’/A’ (early diastolic mitral annular velocity/late diastolic mitral annular velocity), and E/E’ (early diastolic peak velocity of mitral inflow/early diastolic mitral annular velocity) values, differed significantly between the groups. Epicardial fat tissue was significantly higher and flow-mediated dilatation was significantly lower in psoriatic patients than in the controls. Chemerin was significantly positively correlated with age, body mass index, systolic and diastolic blood pressures, waist circumference, E/E’, and epicardial fat tissue. Serum chemerin was significantly negatively correlated with E’, E’/A’, and flow-mediated dilatation. A multiple linear regression analysis showed that chemerin was independently correlated with E/E’. Conclusions: Psoriatic patients exhibit early subclinical atherosclerosis and diastolic dysfunction. Chemerin can be used as a marker to screen for patients with subclinical cardiac involvement

Rational Molecular Design Enables Efficient Blue TADF−OLEDs with Flexible Graphene Substrate

Observation of thermally activated delayed fluorescence (TADF) in conjugated systems redefined the molecular design approach to realize highly efficient organic light emitting diodes (OLEDs) in the early 2010s. Enabling effective reverse intersystem crossing (RISC) by minimizing the difference between singlet and triplet excited state energies (ΔEST) is proven to be a widely applicable and fruitful approach, which results in remarkable external quantum efficiencies (EQE). The efficacy of RISC in these systems is mainly dictated by the first-order mixing coefficient (λ), which is proportional to spin-orbit coupling (HSO) and inversely proportional to ΔEST. While minimizing ΔEST has been the focus of the OLED community over the last decade, the effect of HSO in these systems is largely overlooked. Here, molecular systems with increased HSO are designed and synthesized by substituting selected heteroatoms of high-performance TADF materials with heavy-atom selenium. A new series of multicolor TADF materials with remarkable EQEs are achieved. One of these materials, SeDF-B, results in pure blue emission with EQEs approaching 20%. Additionally, flexible graphene-based electrodes are developed for OLEDs and revealed to have similar performance as standard indium tin oxide (ITO) in most cases. These devices are the first report of TADF based OLEDs that utilize graphene-based anodes

The emergence of projected scaled patterns of extreme temperatures over Europe

This work investigates the scalability of extreme temperatures over the European domain with global warming levels. We have used the EURO-CORDEX ensemble of regional model simulations at 0.11° resolution for daily minimum and maximum temperatures to analyze future changes in extreme weather daily events. Scaling with the annual mean global warming modeled by the driving GCM was applied to future extreme temperature indices changes. Regional changes in each index were scaled by corresponding global warming levels obtained from GCMs. This approach asserts that regional patterns of climate change and average global temperature change are linearly related. It can provide information regarding climate change for periods or emission scenarios when no simulations exist. According to the results, the annual minimum of the lowest temperature of the day (TNn) increases more than the annual maximum of the highest temperature of the day (TXx) for Europe. The multi-model mean of the changes in scaled patterns of extreme temperatures emerges early, around 2020, even before it becomes robust. Individual scaled patterns of TNn and TXx emerge from around 2040

The value of routine measurement of serum calcitonin on insufficient, indeterminate, and suspicious thyroid nodule cytology

Routine calcitonin measurement in patients with nodular thyroid disease is rather controversial. The aim of this study was to evaluate the contribution of serum calcitonin measurement in the diagnostic evaluation of thyroid nodules with insufficient, indeterminate, or suspicious cytology. Out of 1668 patients who underwent thyroidectomy with the diagnosis of nodular thyroid disease and were screened, 873 patients with insufficient, indeterminate, or suspicious fine needle aspiration biopsy results were included in the study. From the total number of patients in this study, 10 (1.1%) were diagnosed as medullary thyroid cancer (MTC) using histopathology. The calcitonin level was detected to be above the assay-specific cut-off in 23 (2.6%) patients ranging between 6.5 - 4450 pg/mL. While hypercalcitoninemia was detected in all 10 MTC patients, a false positive elevation of serum calcitonin was detected in 13 patients (1.5%). Of the MTC group, 7 patients had cytology results that were suspicious for malignancy (Bethesda V), one patient’s cytology showed atypia of undetermined significance (Bethesda III) and two patient’s cytology results were suspicious for follicular neoplasm (Bethesda IV). Among the cases with non-diagnostic cytology (Bethesda I), none of the patients were diagnosed with MTC. In conclusion, routine serum calcitonin measurement can be performed in selected cases rather than in all nodular thyroid patients. While it is reasonable to perform routine calcitonin measurement in patients with Bethesda IV and Bethesda V, this measurement was not useful in Bethesda I patients. In Bethesda III patients, patient-based decisions can be made according to their calcitonin measurement.