190 research outputs found
One-loop approximation of Moller scattering in Krein-space quantization
It has been shown that the negative-norm states necessarily appear in a
covariant quantization of the free minimally coupled scalar field in de Sitter
spacetime [1,2]. In this processes ultraviolet and infrared divergences have
been automatically eliminated [3]. A natural renormalization of the one-loop
interacting quantum field in Minkowski spacetime () has been
achieved through the consideration of the negative-norm states defined in Krein
space. It has been shown that the combination of quantum field theory in Krein
space together with consideration of quantum metric fluctuation, results in
quantum field theory without any divergences [4]. Pursuing this approach, we
express Wick's theorem and calculate M{\o}ller scattering in the one-loop
approximation in Krein space. The mathematical consequence of this method is
the disappearance of the ultraviolet divergence in the one-loop approximation.Comment: 10 page
Dynamics of porous and amorphous magnesium borohydride to understand solid state Mg-ion-conductors
Rechargeable solid-state magnesium batteries are considered for high energy density storage and usage in mobile applications as well as to store energy from intermittent energy sources, triggering intense research for suitable electrode and electrolyte materials. Recently, magnesium borohydride, Mg(BH), was found to be an effective precursor for solid-state Mg-ion conductors. During the mechanochemical synthesis of these Mg-ion conductors, amorphous Mg(BH) is typically formed and it was postulated that this amorphous phase promotes the conductivity. Here, electrochemical impedance spectroscopy of as-received γ-Mg(BH) and ball milled, amorphous Mg(BH) confirmed that the conductivity of the latter is ~2 orders of magnitude higher than in as-received γ-Mg(BH) at 353 K. Pair distribution function (PDF) analysis of the local structure shows striking similarities up to a length scale of 5.1 Å, suggesting similar conduction pathways in both the crystalline and amorphous sample. Up to 12.27 Å the PDF indicates that a 3D net of interpenetrating channels might still be present in the amorphous phase although less ordered compared to the as-received γ-phase. However, quasi elastic neutron scattering experiments (QENS) were used to study the rotational mobility of the [BH] units, revealing a much larger fraction of activated [BH] rotations in amorphous Mg(BH). These findings suggest that the conduction process in amorphous Mg(BH) is supported by stronger rotational mobility, which is proposed to be the so-called “paddle-wheel” mechanism
The link between plant-based diet indices with biochemical markers of bone turn over, inflammation, and insulin in Iranian older adults
Background: The association of plant-based diets and biomarkers of bone, insulin, and inflammation is still unclear. Objectives: We investigated the associations between biomarkers of bone, insulin, and inflammation and three plant-based diet indices: an overall plant-based diet index (PDI); a healthy plant-based diet index (hPDI); and an unhealthy plant-based diet index (uPDI). Methods: We included 178 elderly subjects who referred to health centers in Tehran. Blood and urine samples were collected to measure osteocalcin. The Human C-telopeptide of type â collagen (u-CTX-I), highly sensitive C-reactive protein (hs-CRP), parathyroid hormone (PTH), 25(OH) D, and insulin resistance and sensitivity. We created an overall PDI, hPDI, and uPDI from semi-quantitative food frequency questionnaire (FFQ) data. Results: Dietary groups of Vegetables (r =.15, p =.03), nuts (r =.16, p =.03), dairy (r =.25, p =.001), eggs (r =.27, p <.001), red meat, and animal products (r =.25, p =.001) were directly correlated with osteocalcin. Refined grains were also had a positive association with serum insulin concentration (r =.14, p =.04). PTH levels are inversely associated with PDI score (β = â��0.18, p =.01). Also, serum insulin concentration was negatively associated with PDI score (β = â��0.10, p =.04). Urine CTX-1 levels were significantly associated with hPDI score (β = â��0.06, p =.04). u-CTX-1 levels are inversely associated with uPDI score. This significance did not change with the adjustment of the confounders (β = â��0.28, p <.001). Conclusions: More adherence to PDI and hPDI and less in uPDI may have a beneficial effect on biomarkers of bone, inflammation, and insulin thus preserving chronic diseases. © 2021 The Authors. Food Science & Nutrition published by Wiley Periodicals LL
A review of the MSCA ITN ECOSTORE - Novel complex metal hydrides for efficient and compact storage of renewable energy as hydrogen and electricity
Hydrogen as an energy carrier is very versatile in energy storage applications. Developments in novel, sustainable technologies towards a CO2-free society are needed and the exploration of all-solid-state batteries (ASSBs) as well as solid-state hydrogen storage applications based on metal hydrides can provide solutions for such technologies. However, there are still many technical challenges for both hydrogen storage material and ASSBs related to designing low-cost materials with low-environmental impact. The current materials considered for all-solid-state batteries should have high conductivities for Na+, Mg2+ and Ca2+, while Al3+-based compounds are often marginalised due to the lack of suitable electrode and electrolyte materials. In hydrogen storage materials, the sluggish kinetic behaviour of solid-state hydride materials is one of the key constraints that limit their practical uses. Therefore, it is necessary to overcome the kinetic issues of hydride materials before discussing and considering them on the system level. This review summarizes the achievements of the Marie Skłodowska-Curie Actions (MSCA) innovative training network (ITN) ECOSTORE, the aim of which was the investigation of different aspects of (complex) metal hydride materials. Advances in battery and hydrogen storage materials for the efficient and compact storage of renewable energy production are discussed
Krein Regularization of \lambda\phi^4
We calculate the four-point function in \lambda\phi^4 theory by using Krein
regularization and compare our result, which is finite, with the usual result
in \lambda\phi^4 theory. The effective coupling constant (\lambda_\mu) is also
calculated in this method
Indirect measurement of pinch and pull forces at the shaft of laparoscopic graspers
The grasping instruments used in minimally invasive surgery reduce the ability of the surgeon to feel the forces applied on the tissue, thereby complicating the handling of the tissue and increasing the risk of tissue damage. Force sensors implemented in the forceps of the instruments enable accurate measurements of applied forces, but also complicate the design of the instrument. Alternatively, indirect estimations of tissue interaction forces from measurements of the forces applied on the handle are prone to errors due to friction in the linkages. Further, the force transmission from handle to forceps exhibits large nonlinearities, so that extensive calibration procedures are needed. The kinematic analysis of the grasping mechanism and experimental results presented in this paper show that an intermediate solution, force measurements at the shaft and rod of the grasper, enables accurate measurements of the pinch and pull forces on tissue with only a limited number of calibration measurements. We further show that the force propagation from the shaft and rod to the forceps can be approximated by a linear two-dimensional function of the opening angle of the grasper and the force on the rod
Largest ancient fortress of South-West Asia and the western world?:Recent fieldwork at Sasanian Qaleh Iraj at Pishva, Iran
The article presents recent works at Qale Iraj, near Varamin, Iran. My short contribution is on the Middle Persian ostraka found at the site
Imidazol-1-ylethylindazole Voltage-Gated Sodium Channel Ligands Are Neuroprotective during Optic Neuritis in a Mouse Model of Multiple Sclerosis
[Image: see text] A series of imidazol-1-ylethylindazole sodium channel ligands were developed and optimized for sodium channel inhibition and in vitro neuroprotective activity. The molecules exhibited displacement of a radiolabeled sodium channel ligand and selectivity for blockade of the inactivated state of cloned neuronal Na(v) channels. Metabolically stable analogue 6 was able to protect retinal ganglion cells during optic neuritis in a mouse model of multiple sclerosis
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