Actin‐binding peptides and proteins have numerous applications in the control and monitoring of cellular dynamics. This is effectively demonstrated by the wide usage of protein fusions containing the ...actin‐binding peptide LifeAct and fluorescent proteins for live cell imaging. Despite their popularity, there remains a need for a new generation of actin‐binding probes that are largely orthogonal to cellular processes. We propose that this need could be met by a rational deconstructive approach to well‐characterized actin‐binding peptides such as cofilin. In this work, we report on such an effort that uses structural information about the cofilin‐actin binding interface as a guide for the selection and design of cofilin‐derived peptide sequences (COFPEP). We describe the ability of these peptides to label cytoskeletal structures in live and fixed cells, and further detail methods for their improvement via rational design methods. Finally, we investigate whether these cofilin‐derived fragments can inhibit the formation of cofilin‐actin clusters and rods formed in cells undergoing energetic stress. We postulate that peptides with the ability to disrupt stress‐induced cofilin‐actin structures may have applications in studies of brain ischemia and neurodegenerative disease.
Although tropical regions harbor the greatest arthropod diversity on Earth, the majority of species are taxonomically and scientifically unknown. Furthermore, how they are organized into functional ...communities and distributed among habitats is mostly unstudied. Here we examine species richness, diversity, and community composition of carabid beetles (Coleoptera: Carabidae) and compare them between flooded (FP) and non-flooded terra firme (TF) forests in the Yasuní area of Ecuador. The forest understory was sampled using flight intercept traps (FITs) and systematic hand collections at night in June and July 2011 and 2012, and FITs in October and November 2011. A total of 1,255 Carabidae representing 20 tribes, 54 genera, and 143 morphospecies was collected. Mean number of individuals and mean species richness did not differ significantly between FP and TF; however, numbers of Cicindelini (tiger beetles) and Pentagonicini were higher in TF forest while numbers of Lachnophorini and Scaritini were higher in FP forest. Overall, FP had significantly higher rarefied richness but extrapolation of rarefaction curves using the Chao1 nonparametric diversity estimator show that this difference may decrease with additional sampling. The inverse Simpson index was significantly higher for FP than TF forest. Nonmetric multidimensional scaling (NMDS) ordination and dissimilarity coefficient values show that FP and TF forests maintain unique assemblages with minimal overlap in community composition. Given ongoing anthropogenic pressures, particularly petroleum extraction, and those resulting from climate change, a greater understanding of the richness, diversity and community assemblages of Yasuní rainforest are needed to better conserve the fauna of this megadiverse area of Amazonia.
We consider the flow induced on a heated horizontal boundary. The boundary temperature varies spatially in a sinusoidal manner, which is itself sufficient to generate a flow parallel to the boundary. ...A harmonic modulation in time is superposed upon this such that in addition to the fluctuating flow a time-independent, or steady streaming, flow develops which provides the main focus for this investigation.
The design and performance of a circular array of tightly coupled horizontally polarized dipoles placed close to a ground plane is discussed. The dipoles are resonated with the ground plane below, a ...conducting reflector behind, a capacitive load in front, and a dielectric slab ring above to provide a 3.45:1 impedance bandwidth and consistent radiation patterns near the horizon, both as an omnidirectional radiator and as an array of four sectoral antennas. The design process is simplified by using a unit cell with periodic boundary conditions, and the effects of each resonance are characterized to provide design insight. Then, a theoretical analysis of the radiated fields of the array is performed, explaining nulls found in the radiation pattern near the horizon. A dielectric slab is added to mitigate this problem, and the effects of its dimensions on the radiation pattern and impedance match are presented. The array is fabricated and measured, and excellent agreement between simulation and measurement is observed. The array is found to provide > t1 dBi of horizon gain per sector (8 dBi max) with a cross-polarization ratio better than 18 dB or > t9 dBi of gain as an omnidirectional antenna at the horizon (8 dBi max) with a cross-polarization ratio better than 9 dB.
How animals grow and when they stop growing are key variables for understanding life history evolution. Although theoretically straightforward, it is logistically difficult to take body size ...measurements of wild animals, especially endangered and arboreal primates. Here we employ a method that has gained popularity over the past decade: digital photography combined with parallel lasers. Two laser pointers are set at a known distance apart and then projected on the animal to act as a scale in the photograph. We used this method to estimate limb length and width in a large, cross-sectional sample of mid- to late-adolescent and young adult male chimpanzees at Ngogo in Kibale National Park, Uganda. After several years of modifying our methods, we present a protocol for estimating limb length and width in wild chimpanzees. We found that by mid- to late-adolescence, male chimpanzees have reached adult height, as chimpanzees between 12 and 20 years of age did not differ in their forearm or lower leg lengths. However, mid- to late-adolescent male chimpanzees appear to continue gaining mass, as we found a weak but positive correlation between age and limb width for both forearms and lower legs. Although our method proved relatively precise, we encountered several sources of error throughout this study, such as ensuring that the lasers were indeed parallel and in identifying anatomical landmarks in the photographs. We discuss these challenges with the hope of increasing transparency and collaboration in future studies of primate body size.
We report results of new pair creation experiments using ~100 Joule pulses of the Texas Petawatt Laser to irradiate solid gold and platinum targets, with intensities up to ~1.9 × 10(21) W.cm(-2) and ...pulse durations as short as ~130 fs. Positron to electron (e+/e-) ratios >15% were observed for many thick disk and rod targets, with the highest e+/e- ratio reaching ~50% for a Pt rod. The inferred pair yield was ~ few ×10(10) with emerging pair density reaching ~10(15)/cm(3) so that the pair skin depth becomes < pair jet transverse size. These results represent major milestones towards the goal of creating a significant quantity of dense pair-dominated plasmas with e+/e- approaching 100% and pair skin depth ≪ pair plasma size, which will have wide-ranging applications to astrophysics and fundamental physics.
Children (n = 121, M = 9.86 years, SD = 0.64) and adolescents (n = 101, M = 12.84 years, SD = 0.69) evaluated proactive and passive bystander behaviour to intergroup name‐calling (N = 222, 54% ...female). Scenarios depicted ingroup perpetrators and outgroup victims who were from a stigmatized group (ethnicity) or a non‐stigmatized group (school affiliation), with bystanders depicted as being proactive (intervening to help) or passive (failing to challenge the aggression), counter to their own group's norm. Children and adolescents personally evaluated proactive bystanders more favourably than passive bystanders. However, adolescents, more than children, expected their peers to be more positive about proactive bystanders than passive bystanders in the stigmatized context. Results are discussed in terms of the complexities of bystander decisions and implications for anti‐bullying interventions.
Postmortem CT might provide valuable information in determining the cause of death and understanding disease processes, particularly when combined with traditional autopsy. Pediatric applications of ...postmortem imaging represent a new and rapidly growing field. We describe our experience in establishing a pediatric postmortem CT program and present a discussion of the distinct challenges in developing this type of program in the United States of America, where forensic practice varies from other countries. We give a brief overview of recent literature along with the common imaging findings on postmortem CT that can simulate antemortem pathology.
...the slip is secured distally to the central EDC slip in a side-to-side fashion (Fig 1). Meta-analysis of individual-patient data from EVAR-1, DREAM, OVER and ACE trials comparing outcomes of ...endovascular or open repair for abdominal aortic aneurysm over 5 years. Endovascular repair of abdominal aortic aneurysm in patients physically ineligible for open repair: very long-term follow-up in the EVAR-2 randomized controlled trial.
Neuronal tau reduction confers resilience against β-amyloid and tau-related neurotoxicity in vitro and in vivo. Here, we introduce a novel translational approach to lower expression of the tau gene
...at the transcriptional level using gene-silencing zinc finger protein transcription factors (ZFP-TFs). Following a single administration of adeno-associated virus (AAV), either locally into the hippocampus or intravenously to enable whole-brain transduction, we selectively reduced tau messenger RNA and protein by 50 to 80% out to 11 months, the longest time point studied. Sustained tau lowering was achieved without detectable off-target effects, overt histopathological changes, or molecular alterations. Tau reduction with AAV ZFP-TFs was able to rescue neuronal damage around amyloid plaques in a mouse model of Alzheimer's disease (APP/PS1 line). The highly specific, durable, and controlled knockdown of endogenous tau makes AAV-delivered ZFP-TFs a promising approach for the treatment of tau-related human brain diseases.
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