The guidance of human sperm cells under confinement in quasi-2D microchambers is investigated using a purely physical method to control their distribution. Transport property measurements and simulations are performed with diluted populations, for which effects geometrical concentration studied detail. In particular, trapping transition at convex angular wall features identified analyzed. We also show that highly efficient microratchets can be fabricated by curved asymmetric obstacles take...

It has been shown that a nanoliter chamber separated by wall of asymmetric obstacles can lead to an inhomogeneous distribution self-propelled microorganisms. Although it is well established this rectification effect arises from the interaction between swimmers and noncentrosymmetric pillars, here we demonstrate numerically its efficiency strongly dependent on detailed dynamics individual microorganism. In particular, for case run-and-tumble dynamics, run lengths, rotational diffusion,...

Alzheimer's disease (AD) is a complex disorder that affects the central nervous system causing severe neurodegeneration. This pathology an increasing number of people worldwide due to overall aging human population. In recent years SUMO protein modification has emerged as possible cellular mechanism involved in AD. Some proteins engaged physiopathological process AD, like BACE1, GSK3-β tau, AβPP, and JNK, are fact subject modifications or interactions. Here, we have investigated...

Background and Purpose Chemokines are involved in neuroinflammation contribute to chronic pain processing. The new chemokine prokineticin 2 ( PROK2 ) its receptors PKR 1 have a role inflammatory immunomodulation. In the present study, we investigated involvement of neuropathic pain. Experimental Approach Effects single, intrathecal, perineural s.c. injections antagonist PC1 , or week treatment, on thermal hyperalgesia tactile allodynia was evaluated mice with constriction sciatic nerve CCI...

Abstract Bv8/Prokineticin 2 (PROK2) is a bioactive peptide initially discovered as regulator of gastrointestinal motility. Among multiple biological roles demonstrated for PROK2, it was recently established that PROK2 an insult-inducible endangering mediator cerebral damage. Aim the present study to evaluate and its receptors’ potential involvement in amyloid beta (Aβ) neurotoxicity, hallmark Alzheimer’s disease (AD) various forms traumatic brain injury (TBI). Analyzing primary cortical...

Many bacterial species use flagella for self-propulsion in aqueous media. In the soil, which is a complex and structured environment, water found microscopic channels where viscosity potential depend on composition of soil solution degree saturation. Therefore, motility bacteria might have special requirements. An important genus Bradyrhizobium, with that possess one flagellar system others two different systems. Among latter B. diazoefficiens, may express its subpolar lateral simultaneously...

We study both experimentally and theoretically the driven motion of domain walls in extended amorphous magnetic films patterned with a periodic array asymmetric holes. find two crossed-ratchet effects opposite sign that change preferred sense for wall propagation, depending on whether flat or kinked is moving. By solving numerically simple phi(4) model we show essential physical ingredients this effect are quite generic could be realized other experimental systems involving elastic...

The new chemokine Prokineticin 2 (PROK2) and its receptors (PKR 1 PKR ) have a role in inflammatory pain immunomodulation. Here we identified PROK2 as critical mediator of neuropathic the chronic constriction injury (CCI) sciatic nerve mice demonstrated that blocking prokineticin with two -preferring antagonists (PC1 PC7) reduces damage. mRNA expression was upregulated injured since day 3 post (dpi) ipsilateral DRG 6 dpi. protein overexpression evident Schwann Cells, infiltrating macrophages...

The swimming motility of bacteria is driven by the action bacterial flagellar motors, whose outermost structure a long and thin helicoidal filament. When rotated, fluid medium exerts an anisotropic viscous drag on filaments, ultimately leading to propulsion. filaments are protein-based flexible structures that can break due interactions with flows. Here, we study evolution in soil bacterium Bradyrhizobium diazoefficiens after being exposed shear flows created microchannels, for rates between...

The development of microfluidic devices presents itself as an innovative approach to improving current assisted reproduction techniques, which are far from being highly efficient. design these microdevices is generally very flat, characterized by many channels and all the walls play a fundamental role, located at micrometric distances each other. To study this high-confinement effect, human sperm motion was modeled in two dimensions using Langevin dynamics. cellular density calculated within...

We study the nonequilibrium dynamical regimes of a moving vortex lattice in periodic pinning Josephson junction array (JJA) for finite temperatures case fractional or submatching field. obtain phase diagram current driven JJA as function driving I and temperature T. find that when is by current, depinning transition at ${T}_{p}(I)$ melting ${T}_{M}(I)$ become separated even field which they coincide equilibrium. also distinguish between direction drive, transverse perpendicular to drive. The...

We present a continuum model for the propagation of cracks and fractures in brittle materials. The components strain tensor $\ensuremath{\epsilon}$ are fundamental variables. evolution equations based on free energy that reduces to linear elasticity small $\ensuremath{\epsilon}$, accounts through saturation at large values $\ensuremath{\epsilon}$. regularize by including terms dependent gradients energy. No additional fields introduced, then whole dynamics is perfectly defined. show able...

A detailed numerical study on the directed motion of ac-driven vortices and antivortices in 2D Josephson junction arrays (JJA) with an asymmetric periodic pinning potential is reported. Dc-voltage rectification shows a strong dependence vortex density as well inversion flow direction ac amplitude for wide range around $f$=1/2 ($f$=$Ha^2 / \Phi_0$), good agreement recent experiments by Shal\'om Pastoriza [Phys. Rev. Lett. {\bf 94}, 177001 (2005)]. The structures, spatial temporal...

Abstract Suitable asymmetric microstructures can be used to control the direction of motion in microorganism populations. This rectification process makes it possible accumulate swimmers a region space or sort different swimmers. Here we study numerically how separation depends on specific motility strategies microorganisms involved. Crucial properties such as efficiency and time for two bacterial strains are precisely defined evaluated. In particular, sorting populations inoculated box...

We study the effect of thermal fluctuations in a vortex lattice driven periodic pinning Josephson junction array. The phase diagram current ( $I$) vs temperature $T$) is studied. Above critical ${I}_{c}(T)$ we find moving (MVL) with anisotropic Bragg peaks. For large currents $I\ensuremath{\gg}{I}_{c}(T)$, there melting transition MVL at ${T}_{M}(I)$. When applying small transverse to MVL, negligible dissipation low $T$. an onset motion depinning ${T}_{\mathrm{tr}}(I)<{T}_{M}(I)$.

Many self-propelled microorganisms are attracted to surfaces. This makes their dynamics in restricted geometries very different from that observed the bulk. Swimming along walls is beneficial for directing and sorting cells, but may be detrimental if homogeneous populations desired, such as counting microchambers. In this work, we characterize motion of human sperm cells ∼60 μm long, strongly confined ∼25 shallow chambers. We investigate nature cell trajectories between confining surfaces...

We study the effect of thermal fluctuations in a fully frustrated Josephson junction array driven by current I larger than apparent critical I(c)(T). calculate numerically behavior chiral order parameter Z2 symmetry and transverse helicity modulus [related to U(1) symmetry] as function temperature. find that transition occurs at temperature T(Z2)(I) which is lower T(U(1))(I) for transition. Both transitions could be observed experimentally from measurements longitudinal voltages.

We study the dependence of transport properties square Josephson Junction arrays with direction applied dc current, both experimentally and numerically. present computational simulations current--voltage curves at finite temperatures for a single vortex in an array $L\ifmmode\times\else\texttimes\fi{}L$ junctions ${(Ha}^{2}/{\ensuremath{\Phi}}_{0}{=f=1/L}^{2}),$ experimental measurements $100\ifmmode\times\else\texttimes\fi{}1000$ under low magnetic field corresponding to...

The motion of a domain wall in two-dimensional medium is studied by taking into account the internal elastic degrees freedom and geometrical pinning produced both holes sample boundaries. This study used to analyze conditions needed for optimizing crossed-ratchet effects periodic rectangular arrays asymmetric holes, recently observed experimentally patterned ferromagnetic films. Exact calculation as function geometry numerical simulations have been obtain anisotropic critical fields...

The early phase of life represents a critical period for the development an organism. Interestingly, experiences are able to influence gastrointestinal tract and reactivity colonic inflammatory stress. We recently demonstrated that adult male rats exposed low doses corticosterone during lactation (CORT-nursed rats) protected against experimental colitis induced by intracolonic infusion 2,4,6-trinitrobenzenesulfonic acid (TNBS). Based on these interesting results, we wanted better investigate...

Infertility is a common medical condition encountered by health systems throughout the world. Despite development of complex in vitro fertilization techniques, only one-third these procedures are successful. New lab-on-a-chip that focus on spermatozoa selection require better understanding sperm behavior under ultra-confined conditions order to improve outcomes. Experimental studies combined with models and simulations allow evaluation efficiency different devices during design process. In...