Ultrafast Dynamics of Vibrational Symmetry Breaking in a Charge-ordered Nickelate

The ability to probe symmetry breaking transitions on their natural time scales is one of the key challenges in nonequilibrium physics. Stripe ordering represents an intriguing type of broken symmetry, where complex interactions result in atomic-scale lines of charge and spin density. Although phonon anomalies and periodic distortions attest the importance of electron-phonon coupling in the formation of stripe phases, a direct time-domain view of vibrational symmetry breaking is lacking. We report experiments that track the transient multi-THz response of the model stripe compound La$_{1.75}$Sr$_{0.25}$NiO$_{4}$, yielding novel insight into its electronic and structural dynamics following an ultrafast optical quench. We find that although electronic carriers are immediately delocalized, the crystal symmetry remains initially frozen - as witnessed by time-delayed suppression of zone-folded Ni-O bending modes acting as a fingerprint of lattice symmetry. Longitudinal and transverse vibrations react with different speeds, indicating a strong directionality and an important role of polar interactions. The hidden complexity of electronic and structural coupling during stripe melting and formation, captured here within a single terahertz spectrum, opens new paths to understanding symmetry breaking dynamics in solids.Comment: 21 pages, 4 figures; updated version with journal re

Shape-memory properties of magnetically active triple-shape nanocomposites based on a grafted polymer network with two crystallizable switching segments

Thermo-sensitive shape-memory polymers (SMP), which are capable of memorizing two or more different shapes, have generated significant research and technological interest. A triple-shape effect (TSE) of SMP can be activated e.g. by increasing the environmental temperature (Tenv), whereby two switching temperatures (Tsw) have to be exceeded to enable the subsequent shape changes from shape (A) to shape (B) and finally the original shape (C). In this work, we explored the thermally and magnetically initiated shape-memory properties of triple-shape nanocomposites with various compositions and particle contents using different shape-memory creation procedures (SMCP). The nanocomposites were prepared by the incorporation of magnetite nanoparticles into a multiphase polymer network matrix with grafted polymer network architecture containing crystallizable poly(ethylene glycol) (PEG) side chains and poly(ε-caprolactone) (PCL) crosslinks named CLEGC. Excellent triple-shape properties were achieved for nanocomposites with high PEG weight fraction when two-step programming procedures were applied. In contrast, single-step programming resulted in dual-shape properties for all investigated materials as here the temporary shape (A) was predominantly fixed by PCL crystallites

3D printing of twisting and rotational bistable structures with tuning elements

Three-dimensional (3D) printing is ideal for the fabrication of various customized 3D components with fine details and material-design complexities. However, most components fabricated so far have been static structures with fixed shapes and functions. Here we introduce bistability to 3D printing to realize highly-controlled, reconfigurable structures. Particularly, we demonstrate 3D printing of twisting and rotational bistable structures. To this end, we have introduced special joints to construct twisting and rotational structures without post-assembly. Bistability produces a well-defined energy diagram, which is important for precise motion control and reconfigurable structures. Therefore, these bistable structures can be useful for simplified motion control in actuators or for mechanical switches. Moreover, we demonstrate tunable bistable components exploiting shape memory polymers. We can readjust the bistability-energy diagram (barrier height, slope, displacement, symmetry) after printing and achieve tunable bistability. This tunability can significantly increase the use of bistable structures in various 3D-printed components

Ball Comparison between Three Sixth Order Methods for Banach Space Valued Operators

Three methods of sixth order convergence are tackled for approximating the solution of an equation defined on the finitely dimensional Euclidean space. This convergence requires the existence of derivatives of, at least, order seven. However, only derivatives of order one are involved in such methods. Moreover, we have no estimates on the error distances, conclusions about the uniqueness of the solution in any domain, and the convergence domain is not sufficiently large. Hence, these methods have limited usage. This paper introduces a new technique on a general Banach space setting based only the first derivative and Lipschitz type conditions that allow the study of the convergence. In addition, we find usable error distances as well as uniqueness of the solution. A comparison between the convergence balls of three methods, not possible to drive with the previous approaches, is also given. The technique is possible to use with methods available in literature improving, consequently, their applicability. Several numerical examples compare these methods and illustrate the convergence criteria.This project was funded by the Deanship of Scientific Research (DSR) at King Abdulaziz University, Jeddah, Saudi Arabia, under Grant No. D-540-130-1441. The authors, therefore, acknowledge with thanks DSR for technical and financial support.info:eu-repo/semantics/publishedVersio

Highly Pathogenic Avian Influenza H5N2 in Naturally Infected Turkey Breeder Hens: Virus Distribution, Histopathology, and Host Immune Gene Expression

The outbreak of the highly pathogenic avian influenza virus (HPAI) in 2014- 2015 was by far the largest animal disease outbreak in United States history. The turkey industry was the most affected as nearly 70% of the confirmed cases were in turkeys. This project examined viral distribution, semi-quantitative viral load, histological viral lesions, and gene expression of several immune components in 8 tissues of naturally infected turkey breeder hens during the outbreak. Tissues from clinically and sub-clinically affected turkeys, as well as negative controls were obtained: brain, heart, GI, liver, lung, reproductive tract, spleen, and trachea. Changes in the gene expression of IL-1β, IL-6, IL-10, CCL-5, CXCLi-2, Mx, OASL, IFN-γ, IFIH1, FasL and TRAIL were described. The matrix gene was detected in all 8 of the tissues collected from the clinical and sub-clinical groups. The clinically affected turkeys had significantly higher levels of matrix gene detected in the brain, GI, spleen, and trachea. Histological viral lesions were in general very mild and insignificant. The majority of the histological changes were confined to the trachea and liver and primarily consisted of the infiltration of small numbers of heterophils, lymphocytes, and macrophages. This particular virus was able to evade the host’s immune response using several tactics. It was able to avoid initial detection by suppressing IFIH1 expression, the pro-inflammatory cytokines IL-1β and IL-6, and the antiviral component IFN-γ in the trachea. Undetected, the virus quickly disseminated throughout the body and replicated rapidly. The widespread downregulation of IFN-γ and upregulation of CCL-5 and OASL likely contributed to the pathogenesis. Virus was detected in all of the tissues collected on the positive premise, regardless of clinical status thus illustrating its extreme infectivity. Generally, histological lesions were minimal and cytokine responses were not excessive. Death does not appear to be the result of organ damage/necrosis or even cytokine storm, but purely from immune evasion and excessive viral load in the tissues. Consequently the high viral loads in the tissues resulted in organ failure

Efficient derivation of NPCs, spinal motor neurons and midbrain dopaminergic neurons from hESCs at 3% oxygen

This protocol has been designed to generate neural precursor cells (NPCs) from human embryonic stem cells (hESCs) using a physiological oxygen (O(2)) level of 3% and chemically defined conditions. The first stage involves suspension culture of hESC colonies at 3% O(2), where they acquire a neuroepithelial identity over two weeks. This timescale is comparable to that at 20% O(2), but survival is enhanced. Sequential application of retinoic acid (RA) and purmorphamine (PM), from day 14 to 28, directs differentiation towards spinal motor neurons. Alternatively, addition of FGF-8 and PM generates midbrain dopaminergic neurons. OLIG2 induction in motor neuron precursors is 2-fold greater than at 20% O(2), whereas EN1 is 5-fold enhanced. 3% NPCs can be differentiated into all three neural lineages, and such cultures can be maintained long-term in the absence of neurotrophins. The ability to generate defined cell types at 3% O(2) should represent a significant advance for in vitro disease modelling and potentially cell-based therapies

Rhinacanthus nasutus Extracts Prevent Glutamate and Amyloid-β Neurotoxicity in HT-22 Mouse Hippocampal Cells: Possible Active Compounds Include Lupeol, Stigmasterol and β-Sitosterol

The Herb Rhinacanthus nasutus (L.) Kurz, which is native to Thailand and Southeast Asia, has become known for its antioxidant properties. Neuronal loss in a number of diseases including Alzheimer’s disease is thought to result, in part, from oxidative stress. Glutamate causes cell death in the mouse hippocampal cell line, HT-22, by unbalancing redox homeostasis, brought about by a reduction in glutathione levels, and amyloid-β has been shown to induce reactive oxygen species (ROS) production. Here in, we show that ethanol extracts of R. nasutus leaf and root are capable of dose dependently attenuating the neuron cell death caused by both glutamate and amyloid-β treatment. We used free radical scavenging assays to measure the extracts antioxidant activities and as well as quantifying phenolic, flavonoid and sterol content. Molecules found in R. nasutus, lupeol, stigmasterol and β-sitosterol are protective against glutamate toxicity

Prevalence of thyroid dysfunction in patients with type 2 diabetes

 Background: Diabetes mellitus, a leading cause of death worldwide, is the most common endocrine disorder. Type 2 Diabetes (T2D) and Thyroid Dysfunction (TD) often present together and complicate each other at many levels. Recent studies find out the prevalence of TD in T2D in Malwa Region. Objective of the purpose of this study was to find out the prevalence of TD in patients with T2D.Methods: A match cross-sectional study design was conducted at Department of Medicine, Sri Aurobindo Medical College, from March 2018 to April 2019. Source populations were all patients who live in Malwa Region, Indore. A total of 150 cases were enrolled in this study, 75 cases (TD in T2D) and 75 controls were taken into study.Results: There was no significant difference in age and body mass index (BMI) between groups. The average duration of diabetes was 7.76±5.57 years and mean Hemoglobin A1c (HBA1c) was 8.17±1.66%. Only 29(38.6%) of patients had HbA1c below 7%. There was significant difference (p=0.001) in HbA1c. Prevalence of TD in T2D was significantly more in females. Out of TD in T2D patients, sub-clinical hypothyroid was present in 14.6% hypothyroidism was present in 8% patients and sub-clinical hyperthyroidism and hyperthyroidism was present in 1.3% patients.Conclusions: This study reveals about one in four people living with T2D are suffering from TD in Malwa Region. TD is common in T2D patients and can produce significant metabolic disturbances

Effect of venlafaxine on bone loss associated with ligature-induced periodontitis in Wistar rats

<p>Abstract</p> <p>Background</p> <p>The present study investigated the effects of venlafaxine, an antidepressant drug with immunoregulatory properties on the inflammatory response and bone loss associated with experimental periodontal disease (EPD).</p> <p>Materials and Methods</p> <p>Wistar rats were subjected to a ligature placement around the second upper left molar. The treated groups received orally venlafaxine (10 or 50 mg/kg) one hour before the experimental periodontal disease induction and daily for 10 days. Vehicle-treated experimental periodontal disease and a sham-operated (SO) controls were included. Bone loss was analyzed morphometrically and histopathological analysis was based on cell influx, alveolar bone, and cementum integrity. Lipid peroxidation quantification and immunohistochemistry to TNF-α and iNOS were performed.</p> <p>Results</p> <p>Experimental periodontal disease rats showed an intense bone loss compared to SO ones (SO = 1.61 ± 1.36; EPD = 4.47 ± 1.98 mm, p < 0.001) and evidenced increased cellular infiltration and immunoreactivity for TNF-α and iNOS. Venlafaxine treatment while at low dose (10 mg/kg) afforded no significant protection against bone loss (3.25 ± 1.26 mm), a high dose (50 mg/kg) caused significantly enhanced bone loss (6.81 ± 3.31 mm, p < 0.05). Venlafaxine effectively decreased the lipid peroxidation but showed no significant change in TNF-α or iNOS immunoreactivity.</p> <p>Conclusion</p> <p>The increased bone loss associated with high dose venlafaxine may possibly be a result of synaptic inhibition of serotonin uptake.</p

Determination of nutrient salts by automatic methods both in seawater and brackish water: the phosphate blank

9 páginas, 2 tablas, 2 figurasThe main inconvenience in determining nutrients in seawater by automatic methods is simply solved: the preparation of a suitable blank which corrects the effect of the refractive index change on the recorded signal. Two procedures are proposed, one physical (a simple equation to estimate the effect) and the other chemical (removal of the dissolved phosphorus with ferric hydroxide).Support for this work came from CICYT (MAR88-0245 project) and Conselleria de Pesca de la Xunta de GaliciaPeer reviewe