Onset of Fokker-Planck dynamics within a Closed Finite Spin System

Relaxation according to Fokker-Planck equations is a standard scenario in classical statistical mechanics. It is however not obvious how such an equilibration may emerge within a closed, finite quantum system. We present an analytical and numerical analysis of a system comprising sixteen spins in which spatial inhomogeneities of the magnetization relax approximately in accord with a standard Fokker-Planck equation for a Brownian particle in a parabolic potential

Composition-Controlled Laser-Induced Alloying of Colloidal Au–Cu Hetero Nanoparticles

Due to their optical properties (localized surface plasmon resonance, LSPR), colloidally dispersed metal nanoparticles are well suited for selective heating by high-energy laser radiation above their melting point without being limited by the boiling point of the solvent, which represents an excellent complement to wet-chemical nanoparticle synthesis. By combining wet-chemical synthesis and postsynthesis laser treatment, the advantages of both methods can be used to specifically control the properties of nanoparticles. Especially in the colloidal synthesis of nanoalloys consisting of two or more metals with different redox potentials, wet-chemical synthesis quickly reaches its limits in terms of composition control and homogeneity. For this reason, the direct synthesis path is divided into two parts to take the strengths of both methods. After preparing Au–Cu hetero nanoparticles by wet-chemical synthesis, nanoalloys with previous adjusted composition can be formed by postsynthesis laser treatment. The formation of these nanoalloys can be followed by different characterization methods, such as transmission electron microscopy (TEM), where the fusion of both metal domains and the formation of spherical and homogeneous Au–Cu nanoparticles can be observed. Moreover, the alloy formation can be followed by different shifts of X-ray diffraction (XRD) reflections and LSPR maxima depending on the composition

Radiographic cervical spine degenerative findings: a study on a large population from age 18 to 97 years

AbstractPurposeThe aims of this study were (1) to determine the prevalence of radiographic cervical disc degeneration in a large population of patients aged from 18 to 97 years; (2) to investigate individually the prevalence and distribution of height loss, osteophyte formation, endplate sclerosis and spondylolisthesis; and (3) to describe the patterns of cervical disc degeneration.MethodsA retrospective study was performed. Standard lateral cervical spine radiographs in standing, neutral position of 1581 consecutive patients (723 males, 858 females) with an average age of 41.2 ± 18.2 years were evaluated. Cervical disc degeneration was graded from C2/C3 to C6/C7 based on a validated quantitative grading system. The prevalence and distribution of radiographic findings were evaluated and associations with age were investigated.Results53.9% of individuals had radiographic disc degeneration and the most affected level was C5/C6. The presence and severity of disc degeneration were found to be significantly associated with age both in male and female subjects. The most frequent and severe occurrences of height loss, osteophyte formation, and endplate sclerosis were at C5/C6, whereas spondylolisthesis was most observed at C4/C5. Age was significantly correlated with radiographic degenerative findings. Contiguous levels degeneration pattern was more likely found than skipped level degeneration. The number of degenerated levels was also associated with age.ConclusionsThe presence and severity of radiographic disc degeneration increased with aging in the cervical spine. Older age was associated with greater number of degenerated disc levels. Furthermore, the correlations between age and the degree of degenerative findings were stronger at C5/C6 and C6/C7 than at other cervical spinal levels

Supra-Molecular Assemblies of ORAI1 at Rest Precede Local Accumulation into Puncta after Activation

The Ca2+ selective channel ORAI1 and endoplasmic reticulum (ER)-resident STIM proteins form the core of the channel complex mediating store operated Ca2+ entry (SOCE). Using liquid phase electron microscopy (LPEM), the distribution of ORAI1 proteins was examined at rest and after SOCEactivation at nanoscale resolution. The analysis of over seven hundred thousand ORAI1 positions revealed a number of ORAI1 channels had formed STIM-independent distinct supra-molecular clusters. Upon SOCE activation and in the presence of STIM proteins, a fraction of ORAI1 assembled in micron-sized two-dimensional structures, such as the known puncta at the ER plasma membrane contact zones, but also in divergent structures such as strands, and ring-like shapes. Our results thus question the hypothesis that stochastically migrating single ORAI1 channels are trapped at regions containing activated STIM, and we propose instead that supra-molecular ORAI1 clusters fulfill an amplifying function for creating dense ORAI1 accumulations upon SOCE-activation

Implementing a digital infrastructure for the lab using a central laboratory server and the SiLA2 communication standard

In this report, a fully integrated solution for laboratory digitization is presented. The approach presents a flexible and complete integration method for the digitally assisted workflow. The worker in the laboratory performs procedures in direct interaction with the digitized infrastructure that guides through the process and aids while performing tasks. The digital transformation of the laboratory starts with standardized integration of both new and “smart” lab devices, as well as legacy devices through a hardware gateway module. The open source Standardization in Lab Automation 2 standard is used for device communication. A central lab server channels all device communication and keeps a database record of every measurement, task and result generated or used in the lab. It acts as a central entry point for process management. This backbone enables a process control system to guide the worker through the lab process and provide additional assistance, like results of automated calculations or safety information. The description of the infrastructure and architecture is followed by a practical example on how to implement a digitized workflow. This approach is highly useful for – but not limited to – the biotechnological laboratory and has the potential to increase productivity in both industry and research for example by enabling automated documentation

Accelerating solutions of one-dimensional unsteady PDEs with GPU-based swept time-space decomposition

The expedient design of precision components in aerospace and other high-tech industries requires simulations of physical phenomena often described by partial differential equations (PDEs) without exact solutions. Modern design problems require simulations with a level of resolution difficult to achieve in reasonable amounts of time-even in effectively parallelized solvers. Though the scale of the problem relative to available computing power is the greatest impediment to accelerating these applications, significant performance gains can be achieved through careful attention to the details of memory communication and access. The swept time-space decomposition rule reduces communication between sub-domains by exhausting the domain of influence before communicating boundary values. Here we present a GPU implementation of the swept rule, which modifies the algorithm for improved performance on this processing architecture by prioritizing use of private (shared) memory, avoiding interblock communication, and overwriting unnecessary values. It shows significant improvement in the execution time of finite-difference solvers for one-dimensional unsteady PDEs, producing speedups of 2-9 x for a range of problem sizes, respectively, compared with simple GPU versions and 7-300 x compared with parallel CPU versions. However, for a more sophisticated one-dimensional system of equations discretized with a second-order finite-volume scheme, the swept rule performs 1.2-1.9 x worse than a standard implementation for all problem sizes. (C) 2017 Elsevier Inc. All rights reserved

Nanosecond Pulsed Laser-Heated Nanocrystals Inside a Metal-Organic Framework Matrix

Investigations on gold and gold-zinc oxide nanocrystals encapsulated in a matrix of a metal-organic framework (ZIF-8) upon plasmonic heating with nanosecond laser pulses are presented. Irradiation of Au@ZIF-8 composite particles leads to heating of the gold core and decomposition of surrounding matrix acting as temperature probe. Cavities inside the ZIF-8 matrix are found on TEM images after irradiation. Their size is determined dependent on laser energy density and the generated heat at the gold core after absorption of a laser pulse approximated. The surrounding of the gold cores can be heated up to ZIF-8 decomposition over a distance up to 60 nm. This represents a method to visualize heat transfer from the gold cores to the ZIF-8 matrix in three dimensions. Studies on ZIF-8 encapsulated Au@ZnO dot-rod particles give insight in heat transfer between the particle components and show the applicability of the method to different, more complex systems. © 2022 The Authors. ChemNanoMat published by Wiley-VCH GmbH

Sagittal wedging of intervertebral discs and vertebral bodies in the cervical spine and their associations with age, sex and cervical lordosis: A large-scale morphological study

AbstractMany recent studies have focused on the functional and clinical importance of cervical lordosis. However, there is little accurate knowledge of the anatomical parameters that constitute cervical lordosis (i.e., the sagittal wedging angles of intervertebral discs and vertebral bodies) and their associations with age and sex. Standing lateral cervical radiographs of 1020 subjects (424 males, 596 females) with a mean age of 36.6 ± 17.0 years (range 7–95 years) were evaluated retrospectively. Cervical lordosis, the sum of intervertebral disc wedging angles from C2/C3 to C6/C7 and the sum of vertebral body wedging angles from C3 to C7 were measured. The sum of intervertebral disc wedging and the sum of vertebral body wedging were 20.6° ± 14.7° and −12.8° ± 10.3°, respectively. The sum of intervertebral disc wedging increased significantly with age and was significantly greater in males than females, whereas there was no sex‐related difference in the sum of vertebral body wedging. The sum of intervertebral disc wedging was negatively correlated with sum of vertebral body wedging. Wedging of discs contributed to C2–C7 cervical lordosis more significantly than wedging of vertebral bodies. There were moderate positive correlations between cervical lordosis and intervertebral disc wedging angles at C3/C4, C4/C5 and C5/C6; weak correlations were observed at C2/C3 and C6/C7. This study constitutes the largest currently available analysis comprehensively documenting the anatomical characteristics of sagittal wedging of intervertebral discs and vertebral bodies in the cervical spine. The findings could improve understanding of the internal architecture of cervical lordosis among clinicians