Influence of Roller Ball Tool in Single Point Incremental Forming of Polymers

Polymers defend the metals in making complex geometries because of their strength to weight ratio. Utilizing the conventional process has become a challenge in manufacturing customized products. Increase in demand of tailored products in minimum quantities with preferred quality creates the need for developing new techniques. Incremental forming process is an emerging flexible technology that can obtain pre-defined profiles through deformation of metals and polymers in desired thickness at a reasonable cost. In this work, single point incremental forming (SPIF) of different polymer materials is done using roller ball tool and modest fixture system. Materials such as polyvinyl chloride (PVC), polypropylene (PP), polycarbonate (PC), high density poly ethylene (HDPE) are considered for this investigation due to high applications in automobile and biomedical area. The experiments are designed to analyse the influence of variable process parameters such as tool diameter, step size, spindle speed and sheet thickness. The analysis is carried out by characterizing the formability with depth of failure, thickness distribution, surface roughness and microstructure evaluation. Based on the result, the spindle speed and sheet thickness show high response in formability, surface roughness and depth of failure. The tool diameter has a significant effect on the surface roughness. PVC shows the springback resistance and cracks are observed in the circumferential route on the transition area among the bottom and side wall portion

An informatics approach to distinguish RNA modifications in nanopore direct RNA sequencing

Reading RNA modifications more precisely in a pocket-sized device. 京都大学プレスリリース. 2022-08-24.Modifications in RNA can influence their structure, function, and stability and play essential roles in gene expression and regulation. Methods to detect RNA modifications rely on biophysical techniques such as chromatography or mass spectrometry, which are low throughput, or on high throughput short-read sequencing techniques based on selectively reactive chemical probes. Recent studies have utilized nanopore-based fourth-generation sequencing methods to detect modifications by directly sequencing RNA in its native state. However, these approaches are based on modification-associated mismatch errors that are liable to be confounded by SNPs. Also, there is a need to generate matched knockout controls for reference, which is laborious. In this work, we introduce an internal comparison strategy termed “IndoC, ” where features such as ‘trace’ and ‘current signal intensity’ of potentially modified sites are compared to similar sequence contexts on the same RNA molecule within the sample, alleviating the need for matched knockout controls. We first show that in an IVT model, ‘trace’ is able to distinguish between artificially generated SNPs and true pseudouridine (Ψ) modifications, both of which display highly similar mismatch profiles. We then apply IndoC on yeast and human ribosomal RNA to demonstrate that previously reported Ψ sites show marked changes in their trace and signal intensity profiles compared with their unmodified counterparts in the same dataset. Finally, we perform direct RNA sequencing of RNA containing Ψ intact with a chemical probe adduct (N-cyclohexyl-N′-β-(4-methylmorpholinium) ethylcarbodiimide [CMC]) and show that CMC reactivity also induces changes in trace and signal intensity distributions in a Ψ specific manner, allowing their separation from high mismatch sites that display SNP-like behavior

Mast Cells in Stress, Pain, Blood-Brain Barrier, Neuroinflammation and Alzheimer’s Disease

Mast cell activation plays an important role in stress-mediated disease pathogenesis. Chronic stress cause or exacerbate aging and age-dependent neurodegenerative diseases. The severity of inflammatory diseases is worsened by the stress. Mast cell activation-dependent inflammatory mediators augment stress associated pain and neuroinflammation. Stress is the second most common trigger of headache due to mast cell activation. Alzheimer’s disease (AD) is a progressive irreversible neurodegenerative disease that affects more women than men and woman’s increased susceptibility to chronic stress could increase the risk for AD. Modern life-related stress, social stress, isolation stress, restraint stress, early life stress are associated with an increased level of neurotoxic beta amyloid (Aβ) peptide. Stress increases cognitive dysfunction, generates amyloid precursor protein (APP), hyperphosphorylated tau, neurofibrillary tangles (NFTs), and amyloid plaques (APs) in the brain. Stress-induced Aβ persists for years and generates APs even several years after the stress exposure. Stress activates hypothalamic-pituitary adrenal (HPA) axis and releases corticotropin-releasing hormone (CRH) from hypothalamus and in peripheral system, which increases the formation of Aβ, tau hyperphosphorylation, and blood-brain barrier (BBB) disruption in the brain. Mast cells are implicated in nociception and pain. Mast cells are the source and target of CRH and other neuropeptides that mediate neuroinflammation. Microglia express receptor for CRH that mediate neurodegeneration in AD. However, the exact mechanisms of how stress-mediated mast cell activation contribute to the pathogenesis of AD remains elusive. This mini-review highlights the possible role of stress and mast cell activation in neuroinflammation, BBB, and tight junction disruption and AD pathogenesis

Polymer membrane stabilized gold nanostructures modified electrode and its application in nitric oxide detection

Nafion polymer/gold nanostructures film that can be utilized as a proficient electrochemical sensor for nitric oxide was prepared by an electrochemical process, forming the gold nanostructures (Au<SUB>nano</SUB>) through infiltration into a Nafion (Nf) matrix preassembled on an electrode. The formation of gold nanostructures was monitored by the in situ spectroelectrochemical method. The in situ absorption spectra of Au<SUB>nano</SUB> showed systematic and uniform formation of gold nanostructures at the Nafion (Nf-Au<SUB>nano</SUB>)-modified electrode. The electrochemically formed Nf-Au<SUB>nano</SUB> was characterized by UV-visible spectroscopy, X-ray diffraction, scanning electron microscope, transmission electron microscope, and electrochemical techniques. The surface plasmon absorption spectra recorded for the wet and dry Nf-Au<SUB>nano</SUB> composite film showed the interaction between the gold nanostructures and the swelled polymer matrix. The longitudinal surface plasmon band and the TEM images observed for the Nf-Au<SUB>nano</SUB> showed the formation of nanorod-like and Y-shaped gold nanostructures in the Nafion matrix. In addition to the nanoparticles, the edge-to-edge interactions lead to the formation of 1D assembly. The electrical communication between the gold nanostructures embedded in the Nafion film improved the electrocatalytic properties of the modified electrode toward NO detection. The Nf-Au<SUB>nano</SUB> electrode showed excellent sensitivity for NO detection with the experimental detection limit of 1 nM. The present Nf-Au<SUB>nano</SUB> electrode is very simple to fabricate and is stable, sensitive, and reproducible

Electrochemical and in situ spectroelectrochemical studies on the gold nanoparticles co-deposited with cobalt hexacyanoferrate modified electrode and its application in sensor

Gold nanoparticles (Aunano) co-deposited with cobalt hexacyanoferrate (CoHCF) modified electrode was prepared by electrodeposition on glassy carbon electrode (represented as GC/Aunano~CoHCF) and characterized. The surface morphology of the modified electrode was studied by AFM and the electrochemical properties were studied by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The co-deposition of Aunano with CoHCF improved the electrochemical behavior of the Aunano~CoHCF modified electrode when compared to CoHCF modified electrode. The in-situ spectroelectrochemical changes of Aunano~CoHCF modified electrode was studied to understand the redox switching of CoHCF in the presence of Aunano. The in-situ spectral study showed that the codeposited Aunano with CoHCF acted as nanoelectrode and improved the electron transfer and redox switching processes when compared to CoHCF modified electrode. An enhanced electrocatalytic oxidation of hydrogen peroxide (H2O2) was observed at the GC/Aunano~CoHCF electrode with an onset potential of 0.5 V when compared to GC/CoHCF electrode. The poly Au electrode did not show a similar oxidation peak for H2O2 oxidation. The Aunano co-deposited with CoHCF (GC/Aunano~CoHCF) significantly enhanced the electrocatalytic property of CoHCF. The amperometric detection of H2O2 was studied at the CoHCF modified electrode in the presence and absence of Aunano and poly Au electrode. The GC/Aunano~CoHCF electrode showed fast sensing response and lower detection limit for H2O2 when compared to GC/CoHCF and poly Au electrode. The electrochemical, in situ spectroelectrochemical and electrocatalytic properties of Aunano co-deposited with CoHCF clearly showed that the GC/Aunano~CoHCF electrode could be used as an electrochemical sensor

Electroless synthesis of multibranched gold nanostructures encapsulated by poly(o-phenylenediamine) in Nafion

Multibranched gold (Au) nanocomposite materials encapsulated by poly(o-phenylenediamine) (PoPD) (Au@PoPD) were synthesized in a Nafion polymer film through the electroless synthetic route. The micro-heterogeneous structured Nafion film acted as a reaction vessel and as the template for the formation of Au@PoPD nanocomposite materials leading to the formation of highly uniform distribution of high density of the polymer-gold nanocomposite material. The formation of Au@PoPD nanomaterials at the GP/Nf surface was scrutinized by recording in situ absorption spectra and was characterized. The formation of the (1 1 1) plane of gold was dominant at the Au@PoPD nanocomposite. The ratio of the benzenoid and quinoid units of the PoPD (ca. 1.65) observed for the Au@PoPD confirmed that the micro-heterogeneous structure of Nf film acted as a reaction vessel and as template for the formation of Au@PoPD nanocomposite material. Both PoPD and Au at the Au@PoPD nanocomposite showed electrochemical activities at the GC/Nf-Au@PoPD modified electrode. The electrocatalytic activity of the GC/Nf-Au@PoPD modified electrode was studied for oxygen reduction reaction (ORR)

Analysis of physical and thermal properties of chiengora fibers

This paper excogitates the potential of an unconventional animal fiber in textile applications. The chiengora fiber taken from dog hair has been chosen for this current study to analyze their chemical, physical, morphological, and thermal properties to explore their usage in textiles. Hairs from five different breeds of dogs namely Labrador, Golden retriever, German shepherd, Pomeranian, and Lhasa apso have been characterized and tested in this study. The research revealed that the chemical, morphological, and thermal properties of the hairs of five breeds are similar to each other. However, marked difference is observed in the physical properties of the fiber such as denier and diameter. It is also found that chiengora fibers have more tenacity than other animal fibers and are very coarser than wool fibers. The X-ray diffraction results reveal that chiengora fibers are having higher crystallinity compared to other animal fibers. Only hairs of Lhasa apso and Pomeranian breed have spinnability characteristics using spinning machines due to their finer denier and higher slenderness ratio and may be spun into yarn to create textile products