Latent Heat Thermal Energy Storage System

Latent heat thermal energy storage systems (LHTESS) are versatile due to their heat source at constant temperature and heat recovery with small temperature drop. In this context, latent heat thermal energy storage system employing phase change material (PCM) is the attractive one due to high-energy storage density with smaller temperature difference between storing and releasing functions. PCMs are generally possessed with low thermal conductivity, which leads to decreased rates of heat storage and extraction during melting and crystallization process. However, the low thermal conductivity of paraffin limits its use as a thermal energy storage material. In this chapter, experiments are conducted to investigate the enhancement of thermal conductivity of paraffin wax by adding alumina nanoparticles. Stable composites containing 5 and 10 vol% nanoparticles in paraffin were prepared by intense sonification. The thermophysical properties of the alumina nanoparticle enhanced paraffin (ANEP) specifically the melting and freezing temperature, latent heat, thermal conductivity, and dynamic viscosity were measured and compared with paraffin wax. These results as well as the thermal conductivity and dynamic viscosity variations with respect to temperature and nanoparticle volume concentration are discussed. Comparison of predicted Maxwell’s model of a recent study shows higher enhancement than the Arasu predicted Maxwell’s model

Chern-Simons theory of magnetization plateaus on the kagome lattice

Frustrated spin systems on Kagome lattices have long been considered to be a promising candidate for realizing exotic spin liquid phases. Recently, there has been a lot of renewed interest in these systems with the discovery of experimental materials such as Volborthite and Herbertsmithite that have Kagome like structures. In this thesis I will focus on studying frustrated spin systems on the Kagome lattice using a spin-1/2 antiferromagnetic XXZ Heisenberg model in the presence of an external magnetic field as well as other perturbations. Such a system is expected to give rise to magnetization platueaus which can exhibit topological characteristics in certain regimes. We will first develop a flux-attachment transformation that maps the Heisenberg spins (hard-core bosons) onto a problem of fermions coupled to a Chern-Simons gauge field. This mapping relies on being able to define a consistent Chern-Simons term on the lattice. Using this newly developed mapping we analyse the phases/magnetization plateaus that arise at the mean-field level and also consider the effects of adding fluctuations to various mean-fi eld states. Along the way, we show how to discretize an abelian Chern-Simons gauge theory on generic 2D planar lattices that satisfy certain conditions. We find that as long as there exists a one-to-one correspondence between the vertices and plaquettes defined on the graph, one can write down a discretized lattice version of the abelian Chern-Simons gauge theory. Using the newly developed flux attachment transformation, we show the existence of chiral spin liquid states for various magnetization plateaus for certain range of parameters in the XXZ Heisenberg model in the presence of an external magnetic field. Speci cally, in the regime of XY anisotropy the ground states at the 1/3 and 2/3 plateau are equivalent to a bosonic fractional quantum Hall Laughlin state with filling fraction 1/2 and that the 5/9 plateau is equivalent to the first bosonic Jain daughter state at filling fraction 2/3. Next, we also consider the effects of several perturbations: a) a chirality term, b) a Dzyaloshinskii-Moriya term, and c) a ring-exchange type term on the bowties of the kagome lattice, and inquire if they can also support chiral spin liquids as ground states. We find that the chirality term leads to a chiral spin liquid even in the absence of an uniform magnetic field, with an effective spin Hall conductance of 1/2 in the regime of XY anisotropy. The Dzyaloshinkii-Moriya term also leads a similar chiral spin liquid but only when this term is not too strong. An external magnetic field when combined with some of the above perturbations also has the possibility of giving rise to additional plateaus which also behave like chiral spin liquids in the XY regime. Under the in influence of a ring-exchange term we find that provided its coupling constant is large enough, it may trigger a phase transition into a chiral spin liquid by the spontaneous breaking of time-reversal invariance. Finally, we also present some numerical results based on some exact diagonalization studies. Here, we specifically focus on the 2/3-magnetization plateau which we previously argued should be a chiral spin liquid with a spin hall conductance of 1/2 . Such a topological state has a non-trivial ground state degeneracy and it excitations are described by semionic quasiparticles. In the numerical analysis, we analyse the ground state degeneracy structure on various Kagome clusters of different sizes. We compute modular matrices from the resultant minimally entangled states as well as the Chern numbers of various eigenstates all of which provide strong evidence that the 2/3-magnetization plateau very closely resembles a chiral spin liquid state with the expected characteristics

Genotoxicity and cytotoxicity of orthodontic bonding adhesives: a review

Orthodontic bonding adhesive is one of the integral parts of orthodontic treatment. By means of orthodontic bonding adhesives, different components of fixed orthodontic appliances are attached to the tooth surface. Manufacturers have been introducing various bonding adhesives as there is an increasing demand for orthodontic treatment presently. Focus has been made more on the physical properties of these bonding adhesives rather than their biocompatibility. As orthodontic treatment is a long-time process, the bonding adhesives also remain in close proximity with intra-oral tissues. Therefore, biocompatibility of these adhesives in respect to their genotoxicity and cytotoxicity should be a concern while clinically implicating them. The aim of this review was to provide information about the genotoxicity and cytotoxicity effects of various orthodontic bonding adhesives. An electronic search was conducted across Cochrane, Medline, Web of Science databases, and Google Scholar for literature analysis on the mentioned topic. The studies were reviewed and compared. This article summarizes the results of research studies that have been done to see the genotoxicity and cytotoxicity of orthodontic bonding adhesives. Most research studies summarized in this review article concluded that orthodontic bonding adhesives show some extent of either genotoxicity or cytotoxicity or both. There is still a lack of scientific literature on long-term in vivo studies on the toxic effects of these adhesives. It is advisable to employ several genetic assays and standardized methods for genotoxic evaluation of bonding adhesives through longtime clinical in vivo studies

SPECTROSCOPIC ANALYSIS AND ANTIBACTERIAL EFFICACY OF BIOACTIVE COMPOUNDS FROM LIMONIA ACIDISSIMA L. FRUIT EXTRACT AGAINST CLINICAL PATHOGENS

Objective: To determine the phytochemical composition using spectral analysis and antibacterial activity of Limonia acidissima fruit methanol extract.Methods: Phytochemical analysis was performed to determine the total alkaloids, saponins, total phenols and flavonoids content of fruit extract. Secondary metabolite compounds were determined performed by FT-IR and GC-MS analysis. Antibacterial activity assay was performed using agar well diffusion technique.Results: The alkaloid and saponins contents of the crude methanol extract were found to be 38.47 g/100 g and 0.13 g/100 g dry matter respectively. The LF methanol extract showed total phenol contents of 33.38 µg/mg and the flavonoids was found to be 33.80 µg/mg extract. FT-IR analysis indicated the presence of phenols, alkanes, amino acids, α, β-unsaturated esters, alkenes, nitro compounds, aromatics, aliphatic amines, carboxylic acid, alkenes, and alkyl halides functional groups. The GC-MS analysis revealed the presence of linoleic acid, octadecanoic acid, hexadecanoic acid, maltol, vinly guaiacol, furanone, and ascorbic acid. The antibacterial activity assay showed dose dependent inhibition against clinical pathogens.Conclusion: This study elucidated the prospective value of L. acidissima fruit as a nutritional and medicinal source. Â

Oscillation properties of second-order quasilinear difference equations with unbounded delay and advanced neutral terms

summary:We obtain some new sufficient conditions for the oscillation of the solutions of the second-order quasilinear difference equations with delay and advanced neutral terms. The results established in this paper are applicable to equations whose neutral coefficients are unbounded. Thus, the results obtained here are new and complement some known results reported in the literature. Examples are also given to illustrate the applicability and strength of the obtained conditions over the known ones

Potential applications of horseshoe crab in biomedical research

Horseshoe crab is one of the oldest existing living fossils comprising four main species today. Of these, Limulus Polyphemus is found in North America and the other three species, Tachypleus tridentatus, Tachypleus gigas and Carcinoscorpius rotundicauda are found in Southeast Asia. Horseshoe crabs play important roles in the regulation of the coastal ecology communities whereby the eggs serve as the main diet of shorebird species during the migrating season. Horseshoe crab is also seen as a versatile organism, useful in the biomedicine field particularly, as its blue blood has been widely integrated to be used for endotoxin tester in vaccines, drugs and injectables. Researchers have explored a material called perivitelline fluid (PVF) from the egg of a fertilized horseshoe crab which is rich in important proteins and amino acids that are crucial for embryogenesis. Previous studies have shown that PVF has the ability to enhance cell growth and differentiation as well as in promoting generation of certain organs. Testing of PVF on many types of cells has shown positive results and hence, it is suggested that PVF could be used as a supplement to support cell growth in future. Highlighting the horseshoe crab as a living fossil, this review brings out the relevance of the blue blood and PVF of the horseshoe crab as sources benefitting molecular research

Cell-to-cell spread of poliovirus in the spinal cord of bonnet monkeys (Macaca radiata)

In order to study the spread of poliovirus in the spinal cord of bonnet monkeys, 10(8) TCID50 Mahoney strain of poliovirus was inoculated into the ulnar nerves of monkeys that were subsequently autopsied on days 1, 2, 3, 6, 9, 12, 14, 15 and 16 postinoculation (p.i.). Virus spread in the spinal cord, the accompanying histopathological changes and paralysis occurred in a cervico-thoraco-lumbar direction. Virus reached the cervical region of the spinal cord within the first 3 days and subsequently spread to all segments of the spinal cord. In situ hybridization demonstrated viral RNA initially in the cervical neurons on day 3 p.i. and in the anterior horn neurons of lumbar segments of the spinal cord by day 6 p.i. Loss of Nissl substance in some of the anterior horn neurons was apparent on day 3 p.i. in the cervical and thoracic regions and by day 6 p.i. in the lumbar region. In the lumbar region, neuronophagia was a consistent feature which was observed on days 6-9 p.i., followed by neuronal dropouts on day 12 p.i. and thereafter. In the cervical and thoracic region, reappearance of Nissl substance was apparent from day 12 p.i. Upper limb paralysis preceded lower limb paralysis (5.5+/-1.73 vs 8.18+/-2.18, P = 0.046), further suggesting that virus spread within the spinal cord was via an intraneural route despite persistent viraemia detectable from day 2 p.i. onwards. The temporal distribution of the virus spread, distribution of viral RNA, histopathological and clinical changes indicate a cell-to-cell spread of poliovirus in the CNS, having gained access to the CNS from the peripheral nerve

A High Fidelity Transmural Anisotropic Ventricular Tissue Model Function to Investigate the Interaction Mechanisms of Drug: An In-Silico Model for Pharmacotherapy

A high fidelity transmural anisotropic ventricular tissue model consisting of endocardial, mid myocardial, and epicardial myocytes were configured to investigate drug interaction, such as Hydroxychloroquine (HCQ), under hypoxia conditions without and with pro-arrhythmic comorbidity like hypokalemia in (a) ventricular tissue b) its arrhythmogenesis for different dosages and (b) two different pacing sequences (Normal and tachycardiac). In-silico ventricular modeling indicates HCQ has an insignificant effect on hypoxia with and without comorbidities, except in the combination of mild hypoxia with moderate hypokalemia condition and severe hypoxia with mild hypokalemia where it initiated a re-entrant arrhythmia. Secondly, incorporating drug dosage variations indicates the 10 μM HCQ created PVCs for all settings except in severe hypoxia conditions where re-entrant arrhythmia occurred. In addition to the dosage of HCQ utilized for treatment, the pacing protocol also influences the appearance of re-entrant arrhythmia only for severe hypoxia with 10 μM HCQ dosage alone. For all other conditions, including tachycardiac pacing protocol, no arrhythmia occurred. These findings infer that the arrhythmic fatality rate due to HCQ treatment for hypoxia can be effectively alleviated by subtly altering or personalizing the dosage of HCQ and aid in the treatment of hypoxia-induced symptoms caused by COVID

Identification and Characterization of Intraoral and Dermal Fibroblasts Revisited

Abstract: Background: Fibroblasts are the common cells used in clinical regenerative medicine and dentistry. These cells are known to appear heterogeneous in vivo. Previous studies have only investigated the biological properties of these cell subpopulations in vitro. Despite sharing similarity in their spindle-shaped appearance, previous literatures revealed that they play distinguished functional and biological activities in the body. Objective: This paper highlights the similarities and differences among these cell subpopulations, particularly between intraoral fibroblasts (human periodontal ligament, gingival and oral mucosa fibroblasts) and dermal fibroblasts based on several factors including their morphology, growth and proliferation rate. Results: It could be suggested that each subpopulation of fibroblasts demonstrate different positionspecified gene signatures and responses towards extracellular signals. These dissimilarities are crucial to be taken into consideration to employ specific methodologies in stimulating these cells in vivo. Conclusion: A comparison of the characteristics of these cell subpopulations is desired for identifying appropriate cellular applications. Keywords: Dermal fibroblast, differences, gingival fibroblast, oral mucosa fibroblast, periodontal ligament fibroblast, similaritie