Physicomechanical and Antimicrobial Characteristics of Cement Composites with Selected Nano-Sized Oxides and Binary Oxide Systems

In recent years, increasing attention has been paid to the durability of building materials, including those based on cementitious binders. Important aspects of durability include the increase of the strength of the cement matrix and enhancement of material resistance to external factors. The use of nanoadditives may be a way to meet these expectations. In the present study, zinc, titanium and copper oxides, used in single and binary systems (to better the effect of their performance), were applied as additives in cement mortars. In the first part of this work, an extensive physicochemical analysis of oxides was carried out, and in the second, their application ranges in cement mortars were determined. The subsequent analyses were employed in determining the physicochemical properties of pristine oxides: Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray fluorescence (EDXRF), scanning electron microscopy (SEM), measurement of the particle size distribution, as well as zeta potential measurement depending on the pH values. Influence on selected physicomechanical parameters of the cement matrix and resistance to the action of selected Gram-positive and Gram-negative bacteria and fungi were also examined. Our work indicated that all nanoadditives worsened the mechanical parameters of mortars during the first 3 days of hardening, while after 28 days, an improvement was achieved for zinc and titanium(IV) oxides. Binary systems and copper(II) oxide deteriorated in strength parameters throughout the test period. In contrast, copper(II) oxide showed the best antibacterial activity among all the tested oxide systems. Based on the inhibitory effect of the studied compounds, the following order of microbial susceptibility to inhibition of growth on cement mortars was established (from the most susceptible, to the most resistant): E. coli < S. aureus < C. albicans < B. cereus = P. aeruginosa < P. putida.

Trends of Studies on Controlled Halogenated Gases under International Conventions during 1999–2018 Using Bibliometric Analysis: A Global Perspective

A lot of research on international convention-controlled halogenated gases (CHGs) has been carried out. However, few bibliometric analyses and literature reviews exist in this field. Based on 734 articles extracted from the Science Citation Index (SCI) Expanded database of the Web of Science, we provided the visualisation for the performance of contributors and trends in research content by using VOSviewer and Science of Science (Sci2). The results showed that the United States was the most productive country, followed by the United Kingdom and China. The National Oceanic and Atmospheric Administration had the largest number of publications, followed by the Massachusetts Institute of Technology (MIT) and the University of Bristol. In terms of disciplines, environmental science and meteorological and atmospheric science have contributed the most. By using cluster analysis of all keywords, four key research topics of CHGs were identified and reviewed: (1) emissions calculation, (2) physicochemical analysis of halocarbons, (3) evaluation of replacements, and (4) environmental impact. The change in research substances is closely related to the phase-out schedule of the Montreal Protocol. In terms of environmental impact, global warming has always been the most important research hotspot, whereas research on ozone-depleting substances and biological toxicity shows a gradually rising trend.

Star-Shaped Polydimethylsiloxanes with Organocyclotetrasilsesquioxane Branching-Out Centers: Synthesis and Properties

New non-crystallizable low-dispersity star-shaped polydimethylsiloxanes (PDMS) containing stereoregular cis-tetra(organo)(dimethylsiloxy)cyclotetrasiloxanes containing methyl-, tolyl- and phenyl-substituents at silicon atoms and the mixture of four stereoisomers of tetra[phenyl(dimethylsiloxy)]cyclotetrasiloxane as the cores were synthesized. Their thermal and viscous properties were studied. All synthesized compounds were characterized by a complex of physicochemical analysis methods: nuclear magnetic resonance (NMR), FT-IR spectroscopy, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), viscometry in solution, rheometry, and Langmuir trough study.

The Dynamics of SARS-CoV-2 Infectivity with Changes in Aerosol Microenvironment

Understanding the factors that influence the airborne survival of viruses such as SARSCoV2 in aerosols is important for identifying routes of transmission and the value of various mitigation strategies for preventing transmission. We present measurements of the stability of SARSCoV2 in aerosol droplets (5 to 10 micrometres equilibrated radius) over timescales spanning from 5 seconds to 20 minutes using a novel instrument to probe survival in a small population of droplets (typically 5-10) containing ~1 virus/droplet. Measurements of airborne infectivity change are coupled with a detailed physicochemical analysis of the airborne droplets containing the virus. A decrease in infectivity to 10 % of the starting value was observable for SARS-CoV-2 over 20 minutes, with a large proportion of the loss occurring within the first 5 minutes after aerosolisation. The initial rate of infectivity loss was found to correlate with physical transformation of the equilibrating droplet; salts within the droplets crystallise at RHs below 50% leading to a near instant loss of infectivity in 50 to 60% of the virus. However, at 90% RH the droplet remains homogenous and aqueous, and the viral stability is sustained for the first 2 minutes, beyond which it decays to only 10% remaining infectious after 10 minutes. The loss of infectivity at high RH is consistent with an elevation in the pH of the droplets, caused by volatilisation of CO2 from bicarbonate buffer within the droplet. Three different variants of SARS-CoV-2 were compared and found to have a similar degree of airborne stability at both high and low RH.

Investigating the Effect of Probiotics as Natural Preservatives on the Microbial and Physicochemical Properties of Yogurt-Marinated Chicken Fillets

Microbial flora of probiotic yogurt can have nutraceutical properties and improve beneficial health effects of food products. In this study, microbial and physicochemical properties of raw chicken fillets dipped in regular yogurt and probiotic yogurt containing Lactobacillus casei, preserved at 4°C for 9 days, were studied. In this regard, microbial analysis (Staphylococcus aureus, fecal coliform, yeasts, and molds) and physicochemical analysis (pH, water holding capacity, cooking loss percentage, Thiobarbituric acid reactive substances, and texture profile analysis) were performed during the storage time. In comparison with control samples, the amount of Staphylococcus aureus, fecal coliforms, yeast and mold counts, pH index, malondialdehyde value, and cooking loss percentage reduced significantly ( P < 0.05 ) in the chicken fillets treated with regular and probiotic yogurt, while the water holding capacity increased in six days. It was concluded that probiotic and regular yogurts reduced microbial growth and improved the physicochemical quality of chicken fillets during storage and cooking time.

A comprehensive analysis of selected medicines collected from private drug outlets of Dhaka city, Bangladesh in a simple random survey

Comprehensive data are needed to prevent substandard and falsified (SF) medicines as they pose a major risk to human health. To assess the quality of selected medicines, samples were collected from random private drug outlets of Dhaka North and South City Corporation, Bangladesh. Sample analysis included visual observation of the packaging, authenticity of the samples, legitimacy and registration verification of the manufacturer, physicochemical analysis, and price. Chemical analysis of the samples was performed using a portable Raman spectroscopy and high-performance liquid chromatography according to the pharmacopoeia. Several discrepancies were noted in the visual observation of samples. Among the 189 collected samples of esomeprazole (ESM), cefixime (CFIX), and amoxicillin-clavulanic acid (CVA-AMPC), 21.2% were confirmed to be authentic, 91.3% manufacturers were confirmed legitimate, and 2.1% of all samples were unregistered. Chemical analysis of the samples revealed that 9.5% (95% CI 5.7–14.6) of samples were SFs. Falsified samples and quality variation in the same generic branded samples were both detected by Raman spectroscopic analysis. Overall, sample prices were satisfactory relative to the international reference price. This study documents the availability of poor-quality medicines, demonstrating the need for immediate attention by the national medicine regulatory authority.

Modification of Kakubhadi Churna into malahara and its physicochemical analysis

Samskara is the process of modification of Guna of a given substance which is responsible for conversion of a raw material into medicine. These Samskara are responsible for the change in quality and property of any medicine. Primary preparations of Bhaisajya Kalpana known as Panchavidha kashaya Kalpana are modified into secondary dosage forms like Vati, Avaleha, Malahara, Sneha kalpana etc in order to achieve better shelf life, easy administration and palatability. Churna kalpana is an Upkalapana of Kalka kalpana, it is mentioned to be used in many disease conditions. One among these is Kakubhadi churna, which is indicated to be sprinkled externally on Dushta Vrana. As this method of application is cumbersome and not patient friendly, an attempt has been made to modify Kakubhadi churna into Malahara. Malahara is similar to ointments and creams in modern pharmaceutics. When compared to Churna, it has as an extended shelf life and also drugs in the form of Malahara are easy to apply and store. Taking all this under consideration, present study was taken up to modify Kakubhadi churna into Malahara. Physico chemical analysis of prepared Churna and Malahara was also done to achieve preliminary standard.

Antimicrobial Activity and Physicochemical Analysis of Bio-degradable Films from Cucurbita pepo and Musa paradisiaca

Cucurbita pepo and Musa paradisiaca can be considered as a large source of starch which makes it appropriate to be used for the preparation of bio-plastic material. In this study, biodegradable films from Cucurbita pepo and Musa paradisiaca were developed and investigated for their properties like pH, ash, moisture content, amylose content, biodegradability, and antimicrobial activity. 1,2,3-Propanetriol, gingelly oil, and agarose gel was used to reduce the brittleness of the developed starch- based bioplastic films. The investigation of films was done by Spectroscopic and Surface Analysis techniques. The developed bio- films showed substantial properties like less engorgement and insolubility in water which makes it worth a commercial viable product for food packaging.

Polypropylene Graft Poly(methyl methacrylate) Graft Poly(N-vinylimidazole) as a Smart Material for pH-Controlled Drug Delivery

Surface modification of polypropylene (PP) films was achieved using gamma-irradiation-induced grafting to provide an adequate surface capable of carrying glycopeptide antibiotics. The copolymer was obtained following a versatile two-step route; pristine PP was exposed to gamma rays and grafted with methyl methacrylate (MMA), and afterward, the film was grafted with N-vinylimidazole (NVI) by simultaneous irradiation. Characterization included Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and physicochemical analysis of swelling and contact angle. The new material (PP-g-MMA)-g-NVI was loaded with vancomycin to quantify the release by UV-vis spectrophotometry at different pH. The surface of (PP-g-MMA)-g-NVI exhibited pH-responsiveness and moderate hydrophilicity, which are suitable properties for controlled drug release.

Analysis of the Impact of Climate Change on Surface Water Quality in North-Eastern Poland

This article presents the influence of climatic conditions on surface water quality. The research methodology, including physicochemical analysis from the Gołdapa and Bludzia rivers, is presented. The research lasted for two years. The results of the physicochemical studies of the Gołdapa and Bludzia rivers in early spring, spring, and autumn show that each of these seasons impacts the quality of surface waters. Moreover, it was proven that all the parameters are strongly correlated with the air temperature, the sum of daily precipitation, and water levels. For detailed analysis, the obtained results of own research were compared with meteorological and hydrological data from the last 15 years (2005–2021) for the region of north-eastern Poland. It was proven that temperature changes contribute to increased surface water pollution in the north-eastern part of Poland. Waters from areas that humans have not developed are of better quality than those that drain the urban area, which is reflected in the case of the superior quality of the Bludzia river compared to the Gołdapa river. The upward trend in temperature in the Gołdap region indicates that global warming will continue.