Optical penetration models for practical prediction of femtosecond laser ablation of dental hard tissue.

Objectives: To develop and practically test high-precision femtosecond laser ablation models for dental hard tissue that are useful for detailed planning of automated laser dental restorative treatment.

Methods: Analytical models are proposed, derived, and demonstrated for practical calculation of ablation rates, ablation efficiency and ablated morphology of human dental enamel and dentin using femtosecond lasers. The models assume an effective optical attenuation coefficient for the irradiated material.

Tongue acceleration in humans evoked with intramuscular electrical stimulation of genioglossus.

Genioglossus was stimulated intramuscularly to determine the effect of regional activation of the muscle on tongue movement in eight healthy adults. Stimulation at motor threshold was delivered with a needle electrode inserted to different depths in the anterior and posterior regions of genioglossus. The current amplitude that induced muscle contraction was ∼80% higher for anterior than posterior sites.

Respiratory muscle activity in voluntary breathing tracking tasks: Implications for the assessment of respiratory motor control.

How the involuntary (bulbospinal) and voluntary (corticospinal) pathways interact in respiratory muscle control is not established. To determine the role of excitatory corticobulbar pathways in humans, studies typically compare electromyographic activity (EMG) or evoked responses in respiratory muscles during hypercapnic and voluntary tasks. Although ventilation is matched between tasks by having participants track signals of ventilation, these tasks may not result in matched respiratory muscle activity.

Effects of Annealing Temperature and Ambient on Metal/PtSe Contact Alloy Formation.

Forming gas annealing is a common process step used to improve the performance of devices based on transition-metal dichalcogenides (TMDs). Here, the impact of forming gas anneal is investigated for PtSe-based devices. A range of annealing temperatures (150, 250, and 350 °C) were used both in inert (0/100% H/N) and forming gas (5/95% H/N) environments to separate the contribution of temperature and ambient.

Impact of Etch Processes on the Chemistry and Surface States of the Topological Insulator BiSe.

The unique properties of topological insulators such as BiSe are intriguing for their potential implementation in novel device architectures for low power and defect-tolerant logic and memory devices. Recent improvements in the synthesis of BiSe have positioned researchers to fabricate new devices to probe the limits of these materials. The fabrication of such devices, of course, requires etching of the topological insulator, in addition to other materials including gate oxides and contacts which may impact the topologically protected surface states.

The upper limb Physiological Profile Assessment: Description, reliability, normative values and criterion validity.

A progressive decline in upper limb function is associated with ageing and disease. In this cross-sectional study we assessed the performance of 367 healthy individuals aged of 20 to 95 years across a battery of upper limb clinical tests, which we have termed the upper limb Physiological Profile Assessment (PPA). The upper limb PPA was designed to quantify the performance of the multiple physiological domains important for adequate function in the upper extremities.

Proprioceptive measurements of perceived hand position using pointing and verbal localisation tasks.

Previous studies revealed that healthy individuals consistently misjudge the size and shape of their hidden hand during a localisation task. Specifically, they overestimate the width of their hand and underestimate the length of their fingers. This would also imply that the same individuals misjudge the actual location of at least some parts of their hand during the task.

Dislocation driven spiral and non-spiral growth in layered chalcogenides.

Two-dimensional materials have shown great promise for implementation in next-generation devices. However, controlling the film thickness during epitaxial growth remains elusive and must be fully understood before wide scale industrial application. Currently, uncontrolled multilayer growth is frequently observed, and not only does this growth mode contradict theoretical expectations, but it also breaks the inversion symmetry of the bulk crystal.

Fermi Level Manipulation through Native Doping in the Topological Insulator BiSe.

The topologically protected surface states of three-dimensional (3D) topological insulators have the potential to be transformative for high-performance logic and memory devices by exploiting their specific properties such as spin-polarized current transport and defect tolerance due to suppressed backscattering. However, topological insulator based devices have been underwhelming to date primarily due to the presence of parasitic issues. An important example is the challenge of suppressing bulk conduction in BiSe and achieving Fermi levels ( E) that reside in between the bulk valence and conduction bands so that the topologically protected surface states dominate the transport.

Noise and diffusion of a vibrated self-propelled granular particle.

Granular materials are an important physical realization of active matter. In vibration-fluidized granular matter, both diffusion and self-propulsion derive from the same collisional forcing, unlike many other active systems where there is a clean separation between the origin of single-particle mobility and the coupling to noise. Here we present experimental studies of single-particle motion in a vibrated granular monolayer, along with theoretical analysis that compares grain motion at short and long time scales to the assumptions and predictions, respectively, of the active Brownian particle (ABP) model.

An Approach to the Core of Lactonamycin.

A cascade reaction has been developed for the synthesis of lactonamycin. In this paper, we demonstrate that a transition-metal-free thermal ene-diyne cyclization can be used for the construction of the entire core of the antibiotic lactonamycin and anticancer agent lactonamycin Z.

Salience-driven overestimation of total somatosensory stimulation.

Psychological characterisation of sensory systems often focusses on minimal units of perception, such as thresholds, acuity, selectivity and precision. Research on how these units are aggregated to create integrated, synthetic experiences is rarer. We investigated mechanisms of somatosensory integration by asking volunteers to judge the total intensity of stimuli delivered to two fingers simultaneously.

Anaesthesia changes perceived finger width but not finger length.

The brain needs information about the size of the body to control our interactions with the environment. No receptor signals this information directly; the brain must determine body size from multiple sensory inputs and then store this information. This process is poorly understood, but somatosensory information is thought to play a role.

The contribution of motor commands to position sense differs between elbow and wrist.

Recent studies have suggested that centrally generated motor commands contribute to the perception of position and movement at the wrist, but not at the elbow. Because the wrist and elbow experiments used different methods, this study was designed to resolve the discrepancy. Two methods were used to test both the elbow and wrist (20 subjects each).

Is this my finger? Proprioceptive illusions of body ownership and representation.

Body 'ownership' defines which things belong to us and can be manipulated by signals from cutaneous or muscle receptors. Whether signals from muscle proprioceptors on their own influence perceived ownership is unknown. We used finger-joint movement to induce illusory ownership of an artificial finger without vision.

A remarkable multicomponent cascade sequence for the formation of a spirocyclic polyether.

A reaction of 2-hydroxy-2-methylbutan-3-one with sodium hydride in the presence or absence of ethyl formate after acid workup gave the spirocyclic ether 3.

Proprioceptive signals contribute to the sense of body ownership.

The sense of body ownership, knowledge that parts of our body ‘belong’ to us, is presumably developed using sensory information. Cutaneous signals seem ideal for this and can modify the sense of ownership. For example, an illusion of ownership over an artificial rubber hand can be induced by synchronously stroking both the subject’s hidden hand and a visible artificial hand.

Overestimation of force during matching of externally generated forces.

If a weight is applied to a finger and the subject asked to produce the same force, the subject generates a force larger than the weight. That is, subjects overestimate the force applied by an external target when matching it. Details of this force overestimation are not well understood.

Illusory movements of a phantom hand grade with the duration and magnitude of motor commands.

The senses of limb movement and position are critical for accurate control of movement. Recent studies show that central signals of motor command contribute to the sense of limb position but it is not clear whether such signals influence the distinctly different sense of limb movement. Nine subjects participated in two experiments in which we inflated a cuff around their upper arm to produce an ischaemic block, paralysing and anaesthetising the forearm, wrist and hand.

The combined effect of muscle contraction history and motor commands on human position sense.

Along with afferent information, centrally generated motor command signals may play a role in joint position sense. Isometric muscle contractions can produce a perception of joint displacement in the same direction as the joint would move if unrestrained. Contradictory findings of perceived joint displacement in the opposite direction have been reported.

Effect of a peripheral nerve block on torque produced by repetitive electrical stimulation.

Neuromuscular electrical stimulation (NMES) generates contractions by activation of motor axons (peripheral mechanism), but the afferent volley also contributes by recruiting spinal motoneurons synaptically (central mechanism), which recruits motoneurons according to Henneman's size principle. Thus, we hypothesized that contractions that develop due to a combination of peripheral and central mechanisms will fatigue less rapidly than when electrically evoked contractions are generated by the activation of motor axons alone. Plantar-flexion torque evoked by NMES over the triceps surae was compared in five able-bodied subjects before (Intact) and during (Blocked) a complete anesthetic block of the tibial and common peroneal nerves.

High-frequency submaximal stimulation over muscle evokes centrally generated forces in human upper limb skeletal muscles.

Control of posture and movement requires control of the output from motoneurons. Motoneurons of human lower limb muscles exhibit sustained, submaximal activity to high-frequency electrical trains, which has been hypothesized to be partly triggered by monosynaptic Ia afferents. The possibility to trigger such behavior in upper limb motoneurons and the potential unique role of Ia afferents to trigger such behavior remain unclear.

New display of the timing and firing frequency of single motor units.

The neural control of important rhythmical processes such as breathing and locomotion is complex. It is often necessary to depict the activity of motor (or other) units throughout the cycles. We describe and illustrate a novel method that displays visually seven key variables in a single figure related to the timing and frequencies of the discharge of single motor units.

Warm-up stretches reduce sensations of stiffness and soreness after eccentric exercise.

Purpose: A commonly used method for warm-up before exercise is to stretch muscles. How this benefits performance remains uncertain. After a period of eccentric exercise, there is muscle damage accompanied by an increase in passive tension, perceived as a sensation of increased stiffness in the exercised muscles.