New endoperoxides highly active in vivo and in vitro against artemisinin-resistant Plasmodium falciparum

Background: The emergence and spread of Plasmodium falciparum resistance to artemisinin-based combination therapy in Southeast Asia prompted the need to develop new endoperoxide-type drugs. Methods: A chemically diverse library of endoperoxides was designed and synthesized. The compounds were screened for in vitro and in vivo anti-malarial activity using, respectively, the SYBR Green I assay and a mouse model. Ring survival and mature stage survival assays were performed against artemisinin-resistant and artemisinin-sensitive P. falciparum strains. Cytotoxicity was evaluated against mammalian cell lines V79 and HepG2, using the MTT assay. Results: The synthesis and anti-malarial activity of 21 new endoperoxide-derived compounds is reported, where the peroxide pharmacophore is part of a trioxolane (ozonide) or a tetraoxane moiety, flanked by adamantane and a substituted cyclohexyl ring. Eight compounds exhibited sub-micromolar anti-malarial activity (IC50 0.3–71.1 nM), no cross-resistance with artemisinin or quinolone derivatives and negligible cytotoxicity towards mammalian cells. From these, six produced ring stage survival < 1% against the resistant strain IPC5202 and three of them totally suppressed Plasmodium berghei parasitaemia in mice after oral administration. Conclusion: The investigated, trioxolane–tetrazole conjugates LC131 and LC136 emerged as potential anti-malarial candidates; they show negligible toxicity towards mammalian cells, ability to kill intra-erythrocytic asexual stages of artemisinin-resistant P. falciparum and capacity to totally suppress P. berghei parasitaemia in mice.info:eu-repo/semantics/publishedVersio

Experimental investigations of electrodeposited Zn-Ni, Zn-Co, and Ni-Cr-Co-based novel coatings on AA7075 substrate to ameliorate the mechanical, abrasion, morphological, and corrosion properties for automotive applications

The aluminum (Al) alloy AA7075 is widely used in various industries due to its high strength-to-weight ratio, which is comparable and replaceable to steel in many applications. However, it has poor resistance to wear and corrosion compared to other Al alloys. The conventional pressure die coating with Cr and cadmium has led to premature failure while the load is applied. It is indeed to develop a novel coating method to improve the mechanical, wear, and corrosion properties of AA7075 Al alloy. In the present investigation, the binary and ternary metals such as zinc-nickel (Zn-Ni), zinc-cobalt (Zn-Co), and nickel-chromium-cobalt (Ni-Cr-Co) are electroplated on the substrate material (AA7075). In order to ensure optimal coating adhesion, the surface of the substrate material was pre-treated with laser surface treatment (LST). The mechanical and corrosion studies have been carried out on the uncoated and coated materials. It is observed from the findings that the ternary coating has higher wear resistance than the binary-coated material. The ternary coating has 64% higher resistance in the non-heat-treated status and 67% higher resistance in the heat-treated condition compared to the uncoated specimens. The tensile strength (MPa) of Ni-Cr-Co on AA7075 pressure die casting (PDC) is higher than the other deposits (582.24 of Ni-Cr-Co > 566.07 of Zn-Co > 560.05 of Zn-Ni > 553.64 of uncoated condition). The presence of a crystalline structure with the high alignment of Co and Ni atoms could significantly improve the corrosion resistance of Ni-Cr-Co coatings on AA 7075 PDC substrates when compared to binary coatings. The scanning electron microscopy (SEM) images, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy findings on the coated materials have been corroborated with the analyses on mechanical and corrosion properties. The XRD analysis of the Zn-Ni binary coating has reported that the diffraction peaks of γ-NiZn3 (831), γ-Ni2Zn11 (330), and 631 with 2θ values 38, 43, and 73° are confirming the presence of Zn-Ni binary deposit on AA7075 PDC substrate. The XRD pattern of Zn-Co-coated material has revealed that the presence of three strong peaks such as Zn (110), Co (111), and CoZn (211) and two feeble peaks such as ϵ-CoZn3 (220) and ϵ-CoZn3 (301) are clearly visible. The XRD pattern of Ni-Cr-Co ternary coating has exhibited that the Ni-Cr-Co ternary deposit is a solid solution with a body-centered cubic structure due to the formation peaks at lattice plane such as (110), (220), and (210) with a crystal lattice constant of 2.88 A°. The SEM image for both the binary- and ternary-coated materials has exhibited that the deposited surface has displayed many shallow pits due to hitting by progressive particles. The SEM image has illustrated the presence of Zn-Ni atoms with smaller globular structure. The surface morphology of binary Zn-Co coating on the PDC AA7075 substrate has unveiled the evenly distributed dot-like structure and submerged Co particles in the galaxy of Zn atoms. To understand the effectiveness of bonding by laser texturing, cross-section SEM has been carried out which furthermore revealed the effective adhesion of Ni-Cr-Co on AA7075 PDC; this could also be the reason for the enhancement of microhardness, wear, and corrosion resistance of the said coating. © 2023 the author(s), published by De Gruyter

Synthesis, magnetic and optical properties of core/shell Co1-xZnxFe2O4/SiO2 nanoparticles

The optical properties of multi-functionalized cobalt ferrite (CoFe2O4), cobalt zinc ferrite (Co0.5Zn0.5Fe2O4), and zinc ferrite (ZnFe2O4) nanoparticles have been enhanced by coating them with silica shell using a modified Stöber method. The ferrites nanoparticles were prepared by a modified citrate gel technique. These core/shell ferrites nanoparticles have been fired at temperatures: 400°C, 600°C and 800°C, respectively, for 2 h. The composition, phase, and morphology of the prepared core/shell ferrites nanoparticles were determined by X-ray diffraction and transmission electron microscopy, respectively. The diffuse reflectance and magnetic properties of the core/shell ferrites nanoparticles at room temperature were investigated using UV/VIS double-beam spectrophotometer and vibrating sample magnetometer, respectively. It was found that, by increasing the firing temperature from 400°C to 800°C, the average crystallite size of the core/shell ferrites nanoparticles increases. The cobalt ferrite nanoparticles fired at temperature 800°C; show the highest saturation magnetization while the zinc ferrite nanoparticles coated with silica shell shows the highest diffuse reflectance. On the other hand, core/shell zinc ferrite/silica nanoparticles fired at 400°C show a ferromagnetic behavior and high diffuse reflectance when compared with all the uncoated or coated ferrites nanoparticles. These characteristics of core/shell zinc ferrite/silica nanostructures make them promising candidates for magneto-optical nanodevice applications

An Economic Study on Income and Expenditure Activities on Nochikuppam Slum Areas, Chennai City

The dimension of the slums is presumed as something that is deteriorating urban areas that is densely populated and contains dilapidated housing, often in multiple occupations, poverty, social disadvantage and other forms of physical and social deprivation. Urbanization is a global phenomenon experienced by economically advanced as well as developing countries. Rapid urbanization due to “pull factor” or the employment opportunity created in the city and “push factor” due to the lack of the same in rural areas and including environmental degradation, has attracted immigrants not only from the rural Tamil Nadu but also from other parts of the country. Growth of industrialization around the Chennai city, famine situation in the rural area, inadequate rain in the rural area, castism, rapidly and vast building construction activity in and around the city and information technology parks, has given surety for skilled, unskilled, semi-skilled jobs which are available to the deserving people. Most of the immigrated families who could not afford formal housing satisfy their need for housing by occupying available vacant land illegally and solving their housing problem and contribute to the creation of slums. In this study mainly aims to the income and expenditure activities of the Nochikuppam slum areas in Chennai city.</jats:p

Viscoelastic behavior of aloevera/hemp/flax sandwich laminate composite reinforced with BaSO₄: Dynamic mechanical analysis

In the structural applications, the composite material employs a significant contribution in various industrial applications. In this paper, the experimental nonlinear viscoelastic behavior, tensile and flexural strength properties are analyzed in aloevera /hemp/flax natural fiber sandwich laminate composites (NSLC) with the addition of barium sulfate filler. The dynamic mechanical properties such as storage modulus (E′), loss modulus (E″) and damping factor (Tan δ) are analyzed using dynamic mechanical analyzer as a function of temperature and frequency. The homogeneity, crosslink between the fiber and the matrix of the natural fiber sandwich laminate composite samples are analyzed by a cole-cole plot and complex modulus models. The improvement in flexural strength is observed in the NSLC4 sample (138.34 N/mm2), but the addition of barium sulfate affects the tensile strength (28.8 N/mm2). From the dynamic mechanical analyzer, it is observed that the storage modulus (E′) at the glassy region in the NSLC2 sample is 19.9% whereas in the NSLC4 sample it is 15.57%. Further, the addition of barium sulfate filler enhances the loss modulus (E″) by 28% in NSLC4 sample. The NSLC4 sample shows the better homogeneity in the cole-cole plot and high crosslink between the fiber and the matrix is observed from the complex modulus. </jats:p

A STUDY ON SOCIO-ECONOMIC CONDITIONS OF SLUM HOUSEHOLDS WITH SPECIAL REFERENCE TO PORUR SLUM AREA, CHENNAI CITY

The dimension of the slums is presumed as something that is deteriorating urban areas that is densely populated and contains dilapidated housing, often in multiple occupations, poverty, social disadvantage and other forms of physical and social deprivation. Sprawl is a universal occurrence knowledgeable by inexpensively highly developed fine mounting nations. Hurried sprawl appropriate to “pull factor” or the livelihood occasion fashioned in the city and “push factor” owed to the be deficient in of the equivalent in rustic regions and together with ecological dilapidation, has fascinated settlers not barely as of the rustic state but in addition commencing supplementary fractions of the state. Expansion of mechanization roughly in capital of Tamil Nadu, in deprivation condition in the rustic locale, too little drizzle in the rustic part, castism, hastily and enormous edifice creation doings and approximately the city and in sequence expertise commons, has specified surety for accomplished, inexperienced, semi-skilled employments are existing to the justified citizens. In the present study main aims are income and expenditure activities of the Porur slum areas in Chennai city</jats:p