Advances in the synthesis and scalable manufacturing of single-walled carbon nanotubes (SWCNTs) remain critical to realizing many important commercial applications. Here we review recent ...breakthroughs in the synthesis of SWCNTs and highlight key ongoing research areas and challenges. A few key applications that capitalize on the properties of SWCNTs are also reviewed with respect to the recent synthesis breakthroughs and ways in which synthesis science can enable advances in these applications. While the primary focus of this review is on the science framework of SWCNT growth, we draw connections to mechanisms underlying the synthesis of other 1D and 2D materials such as boron nitride nanotubes and graphene.
Precision experiments, such as the search for a deuteron electric dipole moment using storage rings like COSY, demand for an understanding of the spin dynamics with unprecedented accuracy. In such an ...enterprise, numerical predictions play a crucial role for the development and later application of spin-tracking algorithms. Various measurement concepts involving polarization effects induced by an rf Wien filter and static solenoids in COSY are discussed. The matrix formalism, applied here, deals solely with spin rotations on the closed orbit of the machine, and is intended to provide numerical guidance for the development of beam and spin-tracking codes for rings that employ realistic descriptions of the electric and magnetic bending and focusing elements, solenoids, etc., and a realistically modeled rf Wien filter.
Education is considered one of the most critical human capital investments. But does formal educational attainment "pay off" in terms of job satisfaction? To answer this question, in Study 1 we use a ...meta-analytic technique to examine the correlation between educational attainment and job satisfaction (k = 74, N = 134,924) and find an effect size close to zero. We then build on the job demands-resources (JD-R) model and research that distinguishes between working conditions and perceived stress to theorize that educational attainment involves notable trade-offs. In Study 2 we develop and test a multipath, two-stage mediation model using a nationally representative sample to explore this idea. We find that, while better-educated individuals enjoy greater job resources (income, job autonomy, and job variety), they also tend to incur greater job demands (work hours, task pressure, job intensity, and time urgency). On average, these demands are associated with increased job stress and decreased job satisfaction, largely offsetting the positive gains associated with greater resources. Given that the net relationship between education and job satisfaction emerges as weakly negative, we highlight that important trade-offs underlie the education-job satisfaction link. In supplemental analyses, we identify boundary conditions based on gender and self-employment status (such that being female exacerbates, and being self-employed attenuates, the negative association between education and job satisfaction). Finally, we discuss the practical implications for individuals and organizations, as well as alternative explanations for the education-job satisfaction link.
Spurious signals induced by curved spacetime in the gravity field of the rotating Earth in experiments on the search for the electric dipole moment of charged particles manifested by the spin ...rotation in pure electrostatic storage rings have been analyzed with the focus on effects of Earth’s rotation. It has been found that the rotation of the plane of an electrostatic storage ring together with the Earth generates a nonzero magnetic field. Locally in the storage ring, the spin precession frequency linear in Earth’s rotation is much higher than the frequency of the spin precession caused by the electric dipole moments. It has been argued that the integral spurious spin rotation for a particle on an ideal orbit is strongly suppressed because the contribution from Earth’s rotation is sign-alternating along the storage ring. A background signal quadratic in Earth’s rotation is finite but small.
Tactile information is detected by thermoreceptors and mechanoreceptors in the skin and integrated by the central nervous system to produce the perception of somatosensation. Here we investigate the ...mechanism by which thermal and mechanical stimuli begin to interact and report that it is achieved by the mechanotransduction apparatus in cutaneous mechanoreceptors. We show that moderate cold potentiates the conversion of mechanical force into excitatory current in all types of mechanoreceptors from mice and tactile-specialist birds. This effect is observed at the level of mechanosensitive Piezo2 channels and can be replicated in heterologous systems using Piezo2 orthologs from different species. The cold sensitivity of Piezo2 is dependent on its blade domains, which render the channel resistant to cold-induced perturbations of the physical properties of the plasma membrane and give rise to a different mechanism of mechanical activation than that of Piezo1. Our data reveal that Piezo2 is an evolutionarily conserved mediator of thermal–tactile integration in cutaneous mechanoreceptors.
An algorithm and a system for the operational correction of the harvesting and transport complex composition for harvesting grain crops are developed. The system allows to adjust the structure of ...machine groups for harvesting, transhipment and transportation of grain promptly. The system is based on the machine conditions' real-time monitoring and the transfer of control actions through a single control centre. The use of such organization of work reduces unproductive downtime of machines. As a result, the cost is reduced and the productivity of harvesting and transport groups is growing.
Transient receptor potential (TRP) channels are polymodal molecular sensors involved in numerous physiological processes and implicated in a variety of human diseases. Several structures of the ...founding member of the TRP channel family, TRPV1, are available, all of which were determined for the protein missing the N- and C-termini and the extracellular S5-P-loop. Here, we present structures of the full-length thirteen-lined ground squirrel TRPV1 solved by cryo-EM. Our structures resolve the extracellular cap domain formed by the S5-P-loops and the C-terminus that wraps around the three-stranded β-sheet connecting elements of the TRPV1 intracellular skirt. The cap domain forms a dome above the pore's extracellular entrance, with four portals leading to the ion conductance pathway. Deletion of the cap increases the TRPV1 average conductance, reduces the open probability and affects ion selectivity. Our data show that both the termini and the cap domain are critical determinants of TRPV1 function.
•Interaction of low intensity ultrasound with liquid jet creates vortices.•The vortices serve as a template for the formation of hydroxyapatite crystals.•Ultrasound in non-cavitation mode makes ...smaller particles than in cavitation mode.
The size control of materials is of great importance in research and technology because materials of different size and shape have different properties and applications.
This paper focuses on the synthesis of hydroxyapatite in ultrasound fields of different frequencies and intensities with the aim to find the conditions which allow control of the particles size. The results are evaluated by X-ray diffraction, Transmission Electron Microscopy, morphological and sedimentation analyses. It is shown that the hydroxyapatite particles synthesized at low intensity non-cavitation regime of ultrasound have smaller size than those prepared at high intensity cavitation regime. The explanation of observed results is based on the idea of formation of vortices at the interface between phosphoric acid and calcium hydroxide solution where the nucleation of hydroxyapatite particles is taken place. Smaller vortices formed at high frequency non-cavitation ultrasound regime provide smaller nucleation sites and smaller resulting particles, compared to vortices and particles obtained without ultrasound. Discovered method has a potential of industrial application of ultrasound for the controlled synthesis of nanoparticles.
The study of the approach to the quantum ground state and the possibility to detect displacements of macroscopic bodies close to the quantum limit represent pressing challenges in modern physics. In ...the recent experiment of the JEDI Collaboration at the COSY storage ring, the coherent oscillations of a deuteron beam were detected with an amplitude of only one order of magnitude above the limit of the Heisenberg uncertainty principle of about 40 nm for the one-particle betatron motion. On the other hand, the much discussed search for the permanent electric dipole moment of the proton with an ultimate sensitivity of10−29ecmrequires control of the position of the beam center of gravity with an accuracy of≈5pm. In this paper, we develop the full quantum mechanical treatment of the coherent beam oscillations with ultrasmall amplitudes. In agreement with the Ehrenfest theorem, we find a continuity of the description of the coherent betatron motion from the large classical amplitudes down to the deep quantum region below the one-particle Heisenberg limit. We argue that quantum mechanics does not preclude control of the beam center with subpicometer accuracy.
PDF
