Instantaneous cell migration velocity may be ill-defined

Cell crawling is critical to biological development, homeostasis and disease. In many cases, cell trajectories are quasi-random-walk. In vitro assays on flat surfaces often described such quasi-random-walk cell trajectories as approximations to a solution of a Langevin process. However, experiments show quasi-diffusive behavior at small timescales, indicating that instantaneous velocity and velocity autocorrelations are not well-defined. We propose to characterize mean-squared cell displacement using a modified F\"urth equation with three temporal and spatial regimes: short- and long-time/range diffusion and intermediate time/range ballistic motion. This analysis collapses mean-squared displacements of previously published experimental data onto a single-parameter family of curves, allowing direct comparison between movement in different cell types, and between experiments and numerical simulations. Our method also show that robust cell-motility quantification requires an experiment with a maximum interval between images of a few percent of the cell-motion persistence time or less, and a duration of a few orders-of-magnitude longer than the cell-motion persistence time or more.Comment: 5 pages, plus Supplemental materia

Engineering arbitrary motional ionic state through realistic intensity-fluctuating laser pulses

We present a reliable scheme for engineering arbitrary motional ionic states through an adaptation of the projection synthesis technique for trapped-ion phenomena. Starting from a prepared coherent motional state, the Wigner function of the desired state is thus sculpted from a Gaussian distribution. The engineering process has also been developed to take into account the errors arising from intensity fluctuations in the exciting-laser pulses required for manipulating the electronic and vibrational states of the trapped ion. To this end, a recently developed phenomenological-operator approach that allows for the influence of noise will be applied. This approach furnishes a straightforward technique to estimate the fidelity of the prepared state in the presence of errors, precluding the usual extensive ab initio calculations. The results obtained here by the phenomenological approach, to account for the effects of noise in our engineering scheme, can be directly applied to any other process involving trapped-ion phenomena.Comment: more information at http://www.df.ufscar.br/~quantum

Decoherence in trapped ions due to polarization of the residual background gas

We investigate the mechanism of damping and heating of trapped ions associated with the polarization of the residual background gas induced by the oscillating ions themselves. Reasoning by analogy with the physics of surface electrons in liquid helium, we demonstrate that the decay of Rabi oscillations observed in experiments on 9Be+ can be attributed to the polarization phenomena investigated here. The measured sensitivity of the damping of Rabi oscillations with respect to the vibrational quantum number of a trapped ion is also predicted in our polarization model.Comment: 26 pdf pages with 5 figures, http://www.df.ufscar.br/~quantum

Fermilab E791

Fermilab E791, a very high statistics charm particle experiment, recently completed its data taking at Fermilab's Tagged Photon Laboratory. Over 20 billion events were recorded through a loose transverse energy trigger and written to 8mm tape in the the 1991-92 fixed target run at Fermilab. This unprecedented data sample containing charm is being analysed on many-thousand MIP RISC computing farms set up at sites in the collaboration. A glimpse of the data taking and analysis effort is presented. We also show some preliminary results for common charm decay modes. Our present analysis indicates a very rich yield of over 200K reconstructed charm decays.Comment: 4 pages, 1 figure, LaTe

The Effects of Resistance Training Volume on Skeletal Muscle Proteome

International Journal of Exercise Science 10(7): 1051-1066, 2017. Studies are conflicting to whether low volume resistance training (RT) is as effective as high-volume RT protocols with respect to promoting morphological and molecular adaptations. Thus, the aim of the present study was to compare, using a climbing a vertical ladder, the effects of 8 weeks, 3 times per week, resistance training with 4 sets (RT4), resistance training with 8 sets (RT8) and without resistance training control (CON) on gastrocnemius muscle proteome using liquid chromatography mass spectrometry (LC-MS/MS) and cross sectional area (CSA) of rats. Fifty-two proteins were identified by LC-MS/MS, with 39 in common between the three groups, two in common between RT8 and CON, one in common between RT8 and RT4, four exclusive in the CON, one in the RT8, and four in the RT4. The RT8 group had a reduced abundance of 12 proteins, mostly involved in muscle protein synthesis, carbohydrate metabolism, tricarboxylic acid cycle, anti-oxidant defense, and oxygen transport. Otherwise one protein involved with energy transduction as compared with CON group showed high abundance. There was no qualitative protein abundance difference between RT4 and CON groups. These results revealed that high volume RT induced undesirable disturbances on skeletal muscle proteins, while lower volume RT resulted in similar gains in skeletal muscle hypertrophy without impairment of proteome. The CSA was significantly higher in RT8 group when compared to RT4 group, which was significantly higher than CON group. However, no differences were found between trained groups when the gastrocnemius CSA were normalized by the total body weight

Amphibianâ killing chytrid in Brazil comprises both locally endemic and globally expanding populations

Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), is the emerging infectious disease implicated in recent population declines and extinctions of amphibian species worldwide. Bd strains from regions of diseaseâ associated amphibian decline to date have all belonged to a single, hypervirulent clonal genotype (Bdâ GPL). However, earlier studies in the Atlantic Forest of southeastern Brazil detected a novel, putatively enzootic lineage (Bdâ Brazil), and indicated hybridization between Bdâ GPL and Bdâ Brazil. Here, we characterize the spatial distribution and population history of these sympatric lineages in the Brazilian Atlantic Forest. To investigate the genetic structure of Bd in this region, we collected and genotyped Bd strains along a 2400â km transect of the Atlantic Forest. Bdâ Brazil genotypes were restricted to a narrow geographic range in the southern Atlantic Forest, while Bdâ GPL strains were widespread and largely geographically unstructured. Bd population genetics in this region support the hypothesis that the recently discovered Brazilian lineage is enzootic in the Atlantic Forest of Brazil and that Bdâ GPL is a more recently expanded invasive. We collected additional hybrid isolates that demonstrate the recurrence of hybridization between panzootic and enzootic lineages, thereby confirming the existence of a hybrid zone in the Serra da Graciosa mountain range of Paraná State. Our field observations suggest that Bdâ GPL may be more infective towards native Brazilian amphibians, and potentially more effective at dispersing across a fragmented landscape. We also provide further evidence of pathogen translocations mediated by the Brazilian ranaculture industry with implications for regulations and policies on global amphibian trade.See also the Perspective by Ghosh and FisherPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/122445/1/mec13599.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/122445/2/mec13599_am.pd

A purine metabolic checkpoint that prevents autoimmunity and autoinflammation.

Still's disease, the paradigm of autoinflammation-cum-autoimmunity, predisposes for a cytokine storm with excessive T lymphocyte activation upon viral infection. Loss of function of the purine nucleoside enzyme FAMIN is the sole known cause for monogenic Still's disease. Here we discovered that a FAMIN-enabled purine metabolon in dendritic cells (DCs) restrains CD4+ and CD8+ T cell priming. DCs with absent FAMIN activity prime for enhanced antigen-specific cytotoxicity, IFNγ secretion, and T cell expansion, resulting in excessive influenza A virus-specific responses. Enhanced priming is already manifest with hypomorphic FAMIN-I254V, for which ∼6% of mankind is homozygous. FAMIN controls membrane trafficking and restrains antigen presentation in an NADH/NAD+-dependent manner by balancing flux through adenine-guanine nucleotide interconversion cycles. FAMIN additionally converts hypoxanthine into inosine, which DCs release to dampen T cell activation. Compromised FAMIN consequently enhances immunosurveillance of syngeneic tumors. FAMIN is a biochemical checkpoint that protects against excessive antiviral T cell responses, autoimmunity, and autoinflammation