Our capacity to interface with the nervous system remains overwhelmingly reliant on electrical stimulation devices, such as electrode arrays and cuff electrodes that can stimulate both central peripheral systems. However, has deal multiple challenges, including selectivity, spatial resolution, mechanical stability, implant-induced injury subsequent inflammatory response. Optical techniques may avoid some of these challenges by providing more selective stimulation, higher resolution reduced...

A modular system of techniques and software has been developed for the calibration correction intensity linearity, uniformity response, spatial distortion, image plate decay. With Molecular DynamicsTM Imaging Plate scanner shown to give comparable results MarResearchTM scanner. The ESRF x-ray intensifier/charge-coupled device detectors inherently cause large response distortions, successful data analysis depends on correction. Results synchrotron radiation experiments are presented.

This paper describes a new principle of charged-particle identification by plastic track detectors. We find that the rate chemical etching (by suitable reagent) along heavy ion in depends only on primary ionization rate, which, as particle slows down, increases at uniquely atomic number $Z$ and mass $A$. To identify $Z$, $A$, energy we can either measure known residual range [by analogy with $(\frac{\mathrm{dE}}{\mathrm{dx}})\ensuremath{-}E$ detector] or two points trajectory stack plastics....

. Established guidelines for safe levels of electrical stimulation neural prostheses are based on a limited range the stimulus parameters used clinically. Recent studies have reported particulate platinum (Pt) associated with long-term clinical use these devices, highlighting need more carefully defined safety limits. We previously no adverse effects Pt corrosion products in cochleae guinea pigs following 4 weeks using charge densities far greater than published limits cochlear implants. The...

A Monte Carlo model has been developed to simulate light transport and absorption in neural tissue during infrared stimulation (INS). range of fiber core sizes numerical apertures are compared illustrating the advantages using simulations when designing a delivery system. wavelengths, commonly used for INS, also nerves cochlea, terms both energy absorbed change temperature due laser pulse. Modeling suggests that with diameter 200 μm NA = 0.22 is optimal optical geometry rises spiral ganglion...

The response (track-etching rate) of Lexan polycarbonate detectors increases exponentially with the ionization rate heavy nuclei ($Z>~10$). These have been used to measure charge composition and flux in 1967 low-energy (200- 400-MeV/nucleon) cosmic rays from $12<~Z<~28$.

Antibiotic resistance is a growing concern that driving the exploration of alternative ways killing bacteria. Here we show gold nanoparticles synthesized by mycelium Mucor plumbeus are an effective medium for antimicrobial photodynamic therapy (PDT). These particles spherical in shape, uniformly distributed without any significant agglomeration, and single plasmon band at 522–523 nm. The nanoparticle sizes range from 13 to 25 nm, possess average size 17 ± 4 In PDT, light (from source...

A model to simulate heating as a result of pulse repetitions during infrared neural stimulation (INS), with both single- and multiple-emitters is presented. This allows the temperature increases from trains rather than single pulses be considered. The predicts that using rate 250 Hz typical laser parameters at site results in increase 2.3°C. When multiple sites are used analogy cochlear implants, further depending upon spacing between emitters. However, when light more localized reduced.

A model of infrared neural stimulation (INS) has been developed to allow the temporal characteristics different parameters and geometries be better understood. The uses a finite element approach solve heat equation detailed analysis during INS with both microsecond millisecond laser pulses. When compared experimental data, provides insight into mechanisms behind INS. In particular, suggests that there may two broad regimes INS: process tends limited by total pulse energy for lengths below...

Electrical stimulation has been used for decades in devices such as pacemakers, cochlear implants and more recently deep brain retinal electroceutical treatment of disease. However, current spread from the electrodes limits precision neural activation, leading to a low quality therapeutic outcome or undesired side-effects. Alternative methods optical offer potential deliver higher spatial resolution activation. Direct is possible with infrared light, while visible light can be activate...

Abstract Objective. Compared to electrical stimulation, optogenetic stimulation has the potential improve spatial precision of neural activation in neuroprostheses, but it requires intense light and relatively poor temporal kinetics. We tested effect hybrid which is combination subthreshold optical stimuli, on spectral fidelity cochlea by recording multiunit activity inferior colliculus channelrhodopsin (H134R variant) transgenic mice. Approach. Pulsed or biphasic pulses were delivered...

Abstract Objective. Cochlear implants are among the few clinical interventions for people with severe or profound hearing loss. However, current spread during monopolar electrical stimulation results in poor spectral resolution, prompting exploration of optical as an alternative approach. Enabled by introducing light-sensitive ion channels into auditory neurons (optogenetics), has been shown to activate a more discrete neural area minimal overlap between each frequency channel simultaneous...

We present the results of large scale, three-dimensional magneto-hydrodynamics simulations disc-winds for different initial magnetic field configurations. The jets are followed from source to 90 AU which covers several pixels HST images nearby protostellar jets. Our show that heated along their length by many shocks. compute emission lines produced, and find excellent agreement with observations. jet width is found be between 20 30 while maximum velocities perpendicular up above 100 km/s....

The performance of neuroprostheses, including cochlear and retinal implants, is currently constrained by the spatial resolution electrical stimulation. Optogenetics has improved control neurons in vivo but lacks fast-temporal dynamics required for auditory signalling. objective this study to demonstrate that combining optical stimulation vitro could address some limitations associated with each stimulus modes when used independently.The response murine expressing ChR2-H134 combined was...

In infrared neural stimulation (INS), laser-evoked thermal transients are used to generate small depolarising currents in neurons. The laser exposure poses a moderate risk of damage the target neuron. Indeed, exogenous methods often place neurons under stressful non-physiological conditions, which can hinder ordinary neuronal function and hasten cell death. Therefore, quantifying exposure-dependent probability is essential for identifying safe operating limits INS other interventions...

Introduction Electrical stimulation offers a drug-free alternative for the treatment of many neurological conditions, such as chronic pain. However, it is not easy to selectively activate afferent or efferent fibers mixed nerves, nor their functional subtypes. Optogenetics overcomes these issues by controlling activity in genetically modified fibers, however reliability responses light are poor compared electrical and high intensities required present considerable translational challenges....

The electron impact excitation of Ca+ from the ground state to four terms autoionising configurations 3p53d4s and 3p54s2 is calculated using R-matrix method. Close threshold capture ionisation found be important. Good agreement obtained with measurements Peart Dolder (1975) over a wide energy range.

Abstract Optical stimulation is a paradigm-shifting approach to modulating neural activity that has the potential overcome issue of current spread occurs with electrical by providing focused stimuli. But optical either requires high power infrared light or genetic modification neurons make them responsive lower visible light. This work examines activation auditory following optogenetic via AAV injection in two species (mouse and guinea pig). An Anc80 viral vector was used express...

Objective. Optogenetic stimulation of the auditory nerve offers ability to overcome limitations cochlear implants through spatially precise stimulation, but cannot achieve temporal precision nor fidelity required for good hearing outcomes. Auditory midbrain recordings have indicated a combined (hybrid) approach may permit improvements in without sacrificing spatial by facilitating electrical activation thresholds. However, previous research has been conducted undeafened or acutely deafened...