Visible Light-Activatable Q-dye Molecular Beacons for Long-Term mRNA Monitoring in Neurons

2021 ◽  
Author(s):  
Robin Klimek ◽  
Paul Donlin-Asp ◽  
Claudio Polisseni ◽  
Vanessa Hanff ◽  
Erin Schuman ◽  
...  
Keyword(s):  
Visible Light ◽  
Hippocampal Neurons ◽  
Molecular Beacons ◽  
New Class ◽  
Monitoring Time

Herein, we present a new class of Q-dye molecular beacons (MBs) that can be locally activated with visible light in hippocampal neurons. Our novel architecture increases the available monitoring time...

Design, Synthesis and Use of Phthalocyanines as a New Class of Visible-Light Photoinitiators for Free-Radical and Cationic Polymerizations

2021 ◽  
Author(s):  
Davy-Louis Versace ◽  
Louise Breloy ◽  
Yusuf Yagci ◽  
Ismail Yilmaz ◽  
Ozgur Yavuz
Keyword(s):  
Free Radical ◽  
Visible Light ◽  
Design Synthesis ◽  
New Class ◽  
Optical Stability ◽  
Cationic Polymerizations

Phthalocyanines (Pcs) are interesting molecules offering a fascinating chemistry world which received tremendous interest in the last decade. Their certain features such as high thermal, chemical, and optical stability as...

scholarly journals Effect of Photoinitiator on Precursory Stability and Curing Depth of Thiol-Ene Clickable Gelatin

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1877
Author(s):  
Kai-Hung Yang ◽  
Gabriella Lindberg ◽  
Bram Soliman ◽  
Khoon Lim ◽  
Tim Woodfield ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Visible Light ◽  
Rheological Properties ◽  
Swelling Ratio ◽  
Sodium Persulfate ◽  
Photo Polymerization ◽  
Gelation Kinetics ◽  
The Stability ◽  
Over Time

Recent advances highlight the potential of photopolymerizable allylated gelatin (GelAGE) as a versatile hydrogel with highly tailorable properties. It is, however, unknown how different photoinitiating system affects the stability, gelation kinetics and curing depth of GelAGE. In this study, sol fraction, mass swelling ratio, mechanical properties, rheological properties, and curing depth were evaluated as a function of time with three photo-initiating systems: Irgacure 2959 (Ig2959; 320–500 nm), lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP; 320–500 nm), and ruthenium/sodium persulfate (Ru/SPS; 400–500 nm). Results demonstrated that GelAGE precursory solutions mixed with either Ig2959 or LAP remained stable over time while the Ru/SPS system enabled the onset of controllable redox polymerization without irradiation during pre-incubation. Photo-polymerization using the Ru/SPS system was significantly faster (<5 s) compared to both Ig2959 (70 s) and LAP (50 s). Plus, The Ru/SPS system was capable of polymerizing a thick construct (8.88 ± 0.94 mm), while Ig2959 (1.62 ± 0.49 mm) initiated hydrogels displayed poor penetration depth with LAP (7.38 ± 2.13 mm) in between. These results thus support the use of the visible light based Ru/SPS photo-initiator for constructs requiring rapid gelation and a good curing depth while Ig2959 or LAP can be applied for photo-polymerization of GelAGE materials requiring long-term incubation prior to application if UV is not a concern.

scholarly journals Leopard Density Estimation within an Enclosed Reserve, Namibia Using Spatially Explicit Capture-Recapture Models

Animals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 724
Author(s):  
Noack ◽  
Heyns ◽  
Rodenwoldt ◽  
Edwards
Keyword(s):  
Management Strategies ◽  
Camera Traps ◽  
Spatially Explicit ◽  
Conservation Areas ◽  
Term Survival ◽  
New Class ◽  
Capture Recapture ◽  
Wildlife Populations ◽  
Effective Conservation

The establishment of enclosed conservation areas are claimed to be the driving force for the long-term survival of wildlife populations. Whilst fencing provides an important tool in conservation, it simultaneously represents a controversial matter as it stops natural migration processes, which could ultimately lead to inbreeding, a decline in genetic diversity and local extinction if not managed correctly. Thus, wildlife residing in enclosed reserves requires effective conservation and management strategies, which are strongly reliant on robust population estimates. Here, we used camera traps combined with the relatively new class of spatially explicit capture-recaptured models (SECR) to produce the first reliable leopard population estimate for an enclosed reserve in Namibia. Leopard density was estimated at 14.51 leopards/100 km2, the highest recorded density in Namibia to date. A combination of high prey abundance, the absence of human persecution and a lack of top-down control are believed to be the main drivers of the recorded high leopard population. Our results add to the growing body of literature which suggests enclosed reserves have the potential to harbour high densities and highlight the importance of such reserves for the survival of threatened species in the future.

Is Age the New Class? Economic Crisis and Demographics in European Politics

2016 ◽  
Vol 43 (1) ◽  
pp. 59-71 ◽  
Author(s):  
Jan Erk
Keyword(s):  
Age Groups ◽  
The Political ◽  
Economic Downturn ◽  
New Class ◽  
Political Landscape ◽  
Younger Age ◽  
Material Interests ◽  
Post War ◽  
The Welfare State

As the crisis turns into long-term economic downturn, younger age-groups in Europe seem to be hit with higher levels of unemployment while the welfare state is steadily shrinking. The young have suddenly become a social group united by collective material interests, but does this translate into a sense of a collective political interest? The paper examines to what extent the dominant class-based social science of the post-war years can help us understand the politics of age-groups. The analysis highlights four changes since post-war years: the workplace has changed, impacting socialization; modern media has changed, impacting mobilization; the political landscape is fairly institutionalized, tempering the possibilities for new political concerns to find voice; and those who would define and articulate the political priorities of the young are leaving the Old Continent.

scholarly journals Evaluating Bayesian radiocarbon-dated event-count [REC] models for the study of long-term human and environmental processes

2020 ◽  
Author(s):  
William Christopher Carleton
Keyword(s):  
Forest Fires ◽  
Simulated Data ◽  
Radiocarbon Date ◽  
Radiocarbon Dates ◽  
New Class ◽  
Environmental Processes ◽  
Growth Decline ◽  
Marine Ingression ◽  
Event Times

Chronological uncertainty complicates attempts to use radiocarbon dates as proxies for processes like human population growth/decline, forest fires, and marine ingression. Established approaches involve turning databases of radiocarbon-date densities into single summary proxies that cannot fully account for chronological uncertainty. Here, I use simulated data to explore an alternate Bayesian approach that instead models the data as what they are, namely radiocarbon-dated event-counts. The approach involves assessing possible event-count sequences by sampling radiocarbon date densities and then applying MCMC to estimate the parameters of an appropriate count-based regression model. The regressions based on individual sampled sequences were placed in a multilevel framework, which allowed for the estimation of hyperparameters that account for chronological uncertainty in individual event times. Two processes were used to produce simulated data. One represented a simple monotonic change in event-counts and the other was based on a real palaeoclimate proxy record. In both cases, the method produced estimates that had the correct sign and were consistently biased toward zero. These results indicate that the approach is widely applicable and could form the basis of a new class of quantitative models for use in exploring long-term human and environmental processes.

scholarly journals Selective increase of functional network connectivity in Arc-positive neuronal engrams after long-term potentiation

2020 ◽  
Author(s):  
Yuheng Jiang ◽  
Antonius M.J. VanDongen
Keyword(s):  
Functional Connectivity ◽  
Hippocampal Neurons ◽  
Network Effects ◽  
Network Connectivity ◽  
Long Term Potentiation ◽  
Early Gene ◽  
Memory Traces ◽  
Term Potentiation ◽  
Memory Engram

ABSTRACTNew tools in optogenetics and molecular biology have culminated in recent studies which mark immediate-early gene (IEG)-expressing neurons as memory traces or engrams. Although the activity-dependent expression of IEGs has been successfully utilised to label memory traces, their roles in engram specification is incompletely understood. Outstanding questions remain as to whether expression of IEGs can interplay with network properties such as functional connectivity and also if neurons expressing different IEGs are functionally distinct. We investigated the expression of Arc and c-Fos, two commonly utilised IEGs in memory engram specification, in cultured hippocampal neurons. After pharmacological induction of long-term potentiation (LTP) in the network, we noted an emergent network property of refinement in functional connectivity between neurons, characterized by a global down-regulation of network connectivity, together with strengthening of specific connections. Subsequently, we show that Arc expression correlates with the effects of network refinement, with Arc-positive neurons being selectively strengthened. Arc positive neurons were also found to be located in closer physical proximity to each other in the network. While the expression pattern of IEGs c-Fos and Arc strongly overlaps, Arc was more selectively expressed than c-Fos. These IEGs also act together in coding information about connection strength pruning. These results demonstrate important links between IEG expression and network connectivity, which serve to bridge the gap between cellular correlates and network effects in learning and memory.

scholarly journals Quantification of Internal Filtration in Hollow Fiber Hemodialyzers with Medium Cut-Off Membrane

2018 ◽  
Vol 46 (3) ◽  
pp. 196-204 ◽  
Author(s):  
Anna Lorenzin ◽  
Mauro Neri ◽  
Andrea Lupi ◽  
Martina Todesco ◽  
Monica Santimaria ◽  
...  
Keyword(s):  
Nuclear Imaging ◽  
Chronic Hemodialysis ◽  
Transmembrane Pressure ◽  
Hydraulic Permeability ◽  
Dialysate Flow ◽  
New Class ◽  
Inner Diameter ◽  
Marker Molecule

Background: Inadequate removal of molecules between 5 and 50 KDa may cause long-term complication in chronic hemodialysis. Medium cut-off (MCO) is a new class of membranes with enhanced sieving properties and negligible albumin loss. MCO membrane makes it possible to perform expanded hemodialysis (HDx), a technique based on high internal filtration (IF).The present study is designed to quantify IF in 2 MCO dialyzers (Theranova 400 and 500, Baxter, Deerfield, USA) using a nuclear imaging technique previously validated. Methods: Blood and dialysate compartment pressure drop along with transmembrane pressure; they were measured in a closed in vitro circuit with human blood (blood flow [QB] = 300 and 400 mL/min; dialysate flow 500 mL/min; net ultrafiltration rate 0 mL/min). A non-diffusible marker molecule (albumin macro-aggregates labeled with 99Tc metastable) was injected in the blood compartment and nuclear emission was recorded by a gamma camera. Relative variations in the concentration of the marker molecule along the length of the filter were used to calculate local cross filtration. Results: Based on marker concentration profiles, IF was estimated. For Theranova 400, IF were 29.7 and 41.6 mL/min for QB of 300 and 400 mL/min. For Theranova 500, IF were 31.6 and 53.1 mL/min for QB of 300 and 400 mL/min respectively. Conclusions: MCO membrane provides significant amounts of IF due to the particular combination between hydraulic permeability of the membrane and reduced inner diameter of the fibers. High IF combined with enhanced sieving profile of MCO membrane leads to improved removal of a wider spectrum of uremia retention molecules in HDx, without requiring complex equipment.

Characterization of TAPE-Gelatin as a Potential Bioadhesive

2020 ◽  
Vol 833 ◽  
pp. 189-193
Author(s):  
Angelica Aira A. Ayalin ◽  
Bernell Merwyn S. Go ◽  
Gail Edselle S. Reyes ◽  
Terence Tumolva
Keyword(s):  
Inguinal Hernia ◽  
Production Cost ◽  
Long Term Results ◽  
Medical Field ◽  
Hernia Sac ◽  
New Class ◽  
New Material ◽  
Medical Adhesive

Bioadhesives have much potential in the medical field as an alternative to sutures in internal surgery. They are easier to use and have better long-term results. Improvement of a new class of adhesives, tannic acid-polyethylene glycol (TAPE), was done by mixing it with gelatin, since it was found that TAPE alone could not be applied to certain internal applications like in inguinal hernia. It failed to close a fresh inguinal hernia sac. Characterization tests were done on the new material, TAPE-gelatin, which proved to have a tissue adhesion strength of 0.41 MPa which is 5 times greater than fibrin glue, good blood biocompatibility with blood clotting index of 97.46%, burst pressure strength that can withstand 1000 mL that is 10 times more than the volume in the peritoneal cavity, and cheaper, with a production cost of Php28.50, than commercially available bioadhesives, which can reach up to Php2,000 – Php30,000 per application. With its desirable properties, cheaper production cost, and large potential for scalability, TAPE-gelatin as a new candidate for medical adhesive was established.

scholarly journals The amnestic agent anisomycin disrupts intrinsic membrane properties of hippocampal neurons via a loss of cellular energetics

2019 ◽  
Vol 122 (3) ◽  
pp. 1123-1135 ◽  
Author(s):  
C. J. Scavuzzo ◽  
M. J. LeBlancq ◽  
F. Nargang ◽  
H. Lemieux ◽  
T. J. Hamilton ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Mitochondrial Function ◽  
Neural Activity ◽  
Memory Consolidation ◽  
Hippocampal Neurons ◽  
Membrane Properties ◽  
Long Term Memory ◽  
Term Memory ◽  
Cellular Energetics

The nearly axiomatic idea that de novo protein synthesis is necessary for long-term memory consolidation is based heavily on behavioral studies using translational inhibitors such as anisomycin. Although inhibiting protein synthesis has been shown to disrupt the expression of memory, translational inhibitors also have been found to profoundly disrupt basic neurobiological functions, including the suppression of ongoing neural activity in vivo. In the present study, using transverse hippocampal brain slices, we monitored the passive and active membrane properties of hippocampal CA1 pyramidal neurons using intracellular whole cell recordings during a brief ~30-min exposure to fast-bath-perfused anisomycin. Anisomycin suppressed protein synthesis to 46% of control levels as measured using incorporation of radiolabeled amino acids and autoradiography. During its application, anisomycin caused a significant depolarization of the membrane potential, without any changes in apparent input resistance or membrane time constant. Anisomycin-treated neurons also showed significant decreases in firing frequencies and spike amplitudes, and showed increases in spike width across spike trains, without changes in spike threshold. Because these changes indicated a loss of cellular energetics contributing to maintenance of ionic gradients across the membrane, we confirmed that anisomycin impaired mitochondrial function by reduced staining with 2,3,5-triphenyltetrazolium chloride and also impaired cytochrome c oxidase (complex IV) activity as indicated through high-resolution respirometry. These findings emphasize that anisomycin-induced alterations in neural activity and metabolism are a likely consequence of cell-wide translational inhibition. Critical reevaluation of studies using translational inhibitors to promote the protein synthesis dependent idea of long-term memory is absolutely necessary. NEW & NOTEWORTHY Memory consolidation is thought to be dependent on the synthesis of new proteins because translational inhibitors produce amnesia when administered just after learning. However, these agents also disrupt basic neurobiological functions. We show that blocking protein synthesis disrupts basic membrane properties of hippocampal neurons that correspond to induced disruptions of mitochondrial function. It is likely that translational inhibitors cause amnesia through their disruption of neural activity as a result of dysfunction of intracellular energetics.

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