High-efficiency deflection of high-energy protons through axial channeling in a bent crystal

Beam deflection due to axial channeling in a silicon crystal bent along the 111 axis was observed with 400 GeV/c protons at the CERN Super Proton Synchrotron. The condition for doughnut scattering of protons by the atomic strings of the crystal was attained. Such a condition allowed one to observe a beam deflection of 50 murad with about 30% efficiency. The contribution of hyperchanneled states of protons to the observed beam deflection was less than 2% according to simulation results.     

Asteropsiside A and other asterosaponins from the starfish Asteropsis carinifera

Three asterosaponins were isolated from the tropical starfish Asteropsis carinifera: a new one, asteropsiside A, and two known ones, regularoside A and thornasteroside A. The structure of the new compound was established using 2D NMR spectroscopy and ESI mass spectrometry as the sodium salt of 3-O-sulfonato-(20E)-6-O-{β-d-fucopyranosyl-(1→2)-β-d-galactopyranosyl-(1→4)-[β-d-quinovopyranosyl-(1→2)]-β-d-xylopyranosyl-(1→3)-β-d-quinovopyranosyl}-3β,6α-dihydroxy-5α-cholesta-9(11),20(22)-dien-23-one. Regularoside A and thornasteroside A were shown to display the ability to inhibit the growth of the T-47D and RPMI-7951 tumor cell colonies in vitro.     

Estimating the parameters of audible clinical percussion signals by fitting exponentially damped harmonics

Used for centuries in the clinical practice, audible percussion is a method of eliciting sounds by tapping various areas of the human body either by finger tips or by a percussion hammer. Despite its advantages, pulmonary diagnostics by percussion is still highly subjective, depends on the physician's skills, and requires quiet surroundings. Automation of this well-established technique could help amplify its existing merits while removing the above drawbacks. In this work, clinical percussion signals from normal volunteers are decomposed into a sum of exponentially damped sinusoids (EDS) whose parameters are determined using the Matrix Pencil Method. Some EDS represent transient oscillation modes of the thorax/abdomen excited by the percussion event, while others are associated with the noise. It is demonstrated that relatively few EDS are usually enough to accurately reconstruct the original signal. It is shown that combining the frequency and damping parameters of these most significant EDS allows for efficient classification of percussion signals into the two main types historically known as "resonant" and "tympanic." This classification ability can provide a basis for the automated objective diagnostics of various pulmonary pathologies including pneumothorax. The algorithm can be implemented on an embedded platform for the battlefield and other emergency applications.     

Deflection of high-energy negative particles in a bent crystal through axial channeling and multiple volume reflection stimulated by doughnut scattering

Different kinds of deflection in a silicon crystal bent along the 〈111〉 axis was observed for 150 GeV/c   negative particles, mainly π⁻${\pi }^{-}$ mesons, at one of the secondary beams of the CERN SPS. The whole beam was deflected to one side in quasi-bound states of doughnut scattering (DSB) by atomic strings with the efficiency (95.4 ± 0.2)% and with the peak position close to the bend crystal angle, α=185 μrad$\alpha =185\text{μrad}$. It was observed volume capture of π⁻${\pi }^{-}$ mesons into the DSB states with a probability higher than 7%. A beam deflection opposite to the crystal bend was observed for some orientations of the crystal axis due to doughnut scattering and subsequent multiple volume reflections of π⁻${\pi }^{-}$ mesons by different bent planes crossing the axis.     

Locating an acoustic point source scattered by a skull phantom via time reversal matched filtering

This paper examines the utilization of the time reversal matched filtering method to resolve the location of an acoustic point source beneath a skull phantom (variable thickness layer), without the removal of this layer. This acoustical process is examined experimentally in a water tank immersion system containing an acoustic source, a custom-made skull phantom, and a receiving transducer in a pitch-catch arrangement. The phantom is designed to approximately model the acoustic properties of an average human skull bone (minus the diploe layer), while the variable thickness of the phantom introduces a variable time delay to the acoustic wave, relative to its entry point on the phantom. This variable delay is measured and corrected for, and a matched filtering time reversed process is used to determine the location of the point source. The results of the experiment are examined for various positions of the acoustic source behind the phantom and compared to the reference cases with no phantom present. The average distance between these two cases is found to be 4.36 mm, and within the expected deviation in results due to not accounting for the effects of refraction.     

High-temperature single-hole silicon transistors

We present high-temperature (77 K, 300 K) single-hole n⁺–p⁺–n transistors based on silicon diffusion nanostructures. This is made possible by utilizing a quantum wire with isolated quantum dots, which is naturally formed inside an ultrashallow p⁺-diffusion profile using nonequilibrium diffusion processes.