Absence Of Organic Materials Research Articles

Investigating the effect of halogens on the electronic and optical properties of lead‐free double halide perovskites based on CuBi

AbstractIn recent years, three‐dimensional (3D) lead‐free double halide perovskites have been considered promising candidates for photovoltaic applications due to their high stability and the use of non‐toxic materials, and the absence of organic materials in their structure. The structural, electronic, and optical properties of 3D double Halide perovskites and were investigated in this paper using first‐principles density functional theory (DFT) simulation with BLYP approximation. The results showed that structures and have an indirect band gap, high absorption coefficient, low reflection, and high conductivity. A redshift of absorption edge and band gap shrinkage has been observed in the structure with an increase in the ionic radius of the halogen, which indicates the unique features of structure for photovoltaic applications, LED, laser, and other optoelectronic devices.

Assessment of the Antimicrobial Efficacy of Chlorine Dioxide as Disinfectant in Veterinary Operating Rooms

This study was conducted to assess the efficacy of Chlorine dioxide (ClO2) as a disinfectant in veterinary operating rooms. Four surfaces (surgical table, drain of surgical table, instrument table and wall) inside the operating room of four randomly selected veterinary facilities located within the Greater Manila Area were screened for the bacterial count before and after one hour of disinfection with a ClO2-based disinfectant and a Sodium hypochlorite-based (NaClO) disinfectant. The average bacterial load before the application of treatments to the different surfaces of the operating room of the four facilities included in this study was 70.65cfu/mL. The T-test revealed that the mean log10 reduction of ClO2 was significantly higher compared to the mean log10 reduction of NaClO. This clearly demonstrates that ClO2 was more potent than NaClO in decreasing bacterial colonies on the surfaces of veterinary operating rooms. Results of this study also suggest that the type of surface material affects the disinfection rate and should always be considered in a disinfection protocol. Based on the bacterial characterization of isolated bacteria, a low concentration of ClO2 would be sufficient to produce an immediate effect against gram-negative bacteria and gram-positive in the absence of organic materials.

Human Coronaviruses Do Not Transfer Efficiently between Surfaces in the Absence of Organic Materials.

Human coronaviruses, including SARS-CoV-2, are known to spread mainly via close contact and respiratory droplets. However, other potential means of transmission may be present. Fomite-mediated transmission occurs when viruses are deposited onto a surface and then transfer to a subsequent individual. Surfaces can become contaminated directly from respiratory droplets or from a contaminated hand. Due to mask mandates in many countries around the world, the former is less likely. Hands can become contaminated if respiratory droplets are deposited on them (i.e., coughing or sneezing) or through contact with fecal material where human coronaviruses (HCoVs) can be shed. The focus of this paper is on whether human coronaviruses can transfer efficiently from contaminated hands to food or food contact surfaces. The surfaces chosen were: stainless steel, plastic, cucumber and apple. Transfer was first tested with cellular maintenance media and three viruses: two human coronaviruses, 229E and OC43, and murine norovirus-1, as a surrogate for human norovirus. There was no transfer for either of the human coronaviruses to any of the surfaces. Murine norovirus-1 did transfer to stainless steel, cucumber and apple, with transfer efficiencies of 9.19%, 5.95% and 0.329%, respectively. Human coronavirus OC43 transfer was then tested in the presence of fecal material, and transfer was observed for stainless steel (0.52%), cucumber (19.82%) and apple (15.51%) but not plastic. This study indicates that human coronaviruses do not transfer effectively from contaminated hands to contact surfaces without the presence of fecal material.

A Simple Effective Method for Three-Dimensional Modelling of Cementation, Fracturing and Dissolution of Carbonate Rocks: Illustrated through Oolitic Limestone

Sandstones and many carbonates (e.g., oolitic limestone and other grainstones), comprise solid particulates (grains) and pores, which have a given pore network architecture relationship, and associated porosity—permeability values. Over time, through the process of diagenesis, the pore network architecture may be extensively altered. Changes can include compaction, particle deformation, cementation, dissolution and fracturing, with the pathway followed after deposition depending on factors such as the energy level, rate of burial, degree of biological activity, local heat flow, sediment composition, Eh, pH and the presence or absence of organic materials. Any method that provides a means of modelling changes is therefore highly desirable, in particular, allowing a prediction of changes in porosity and permeability with time. The current work illustrates a simple method that uses freely available open source image analysis software to model the development of cement phases within an oolitic limestone in three-dimensions. As well as cementation, it demonstrates the modelling of fracture development and dissolution processes, and records how porosity and permeability change during such processes.

Stability and virucidal efficacies using powder and liquid forms of fresh charcoal ash and slaked lime against Newcastle disease virus and Avian influenza virus.

Aim:The present study was examined the virucidal activity comparison between fresh charcoal ash (FCA) and slaked lime (SL) against avian influenza virus (AIV) and Newcastle disease virus (NDV), using powder and liquid forms, either in the absence or presence of organic materials. In addition, both FCA and SL were evaluated for the persistence of virucidal activity in wet and dry conditions and stability of the solution.Materials and Methods:Two hundred milligrams of FCA or SL powders were mixed with 100 µl of AIV or NDV in the absence of organic material or 33% of organic materials. In the same time, 400 µl of 1%, 5%, or 10% solution samples were mixed with 100 µl of each virus and then incubated at room temperature for an indicated time. After that, the mixed solution was stop activity of sample using 500 µl of 1M Tris-HCl pH 7.2. Each treatment was titrated onto Madin-Darby canine kidney cells or chicken embryo fibroblasts for AIV or NDV, respectively, for determining the efficacy of viral inactivation. In addition, the stability of powder under the wet-dry condition and solution stability under room temperature was examined.Results:The results demonstrated that the FCA and SL in powder form could inactivate AIV and NDV even in the absence or presence of organic materials. In the liquid form, 5% and 10% of FCA could inactivate AIV and NDV either in the absence or presence of organic materials. Alongside, 1%, 5%, and 10% of SL could inactivate both viruses. 10% of FCA solution could inactivate virus at a shortest time when compared with other concentrations. In addition, the efficacy of wet-dry conditions of FCA was limited when compared with SL. On the other hand, it is demonstrated that the FCA solution was more stable and kept at room temperature longer than SL.Conclusion:The FCA may, hence, be used as an alternative virucide, while applying it to prevent spreading of poultry disease on commercial chicken farms and also backyard chickens, especially in developing countries, including in rural areas of Thailand.

Bactericidal Efficacy of Food Additive-Grade Calcium Hydroxide Against Salmonella Infantis on Eggshells.

The bactericidal efficacy of food additive-grade calcium hydroxide [FdCa(OH)2] was evaluated for inactivation of Salmonella Infantis and Salmonella Enteritidis in liquid and Salmonella Infantis on contaminated eggshells. The activity of FdCa(OH)2 was also compared with that of sodium hypochlorite (NaOCl) containing 150 ppm chlorine (150 ppm NaOCl). FdCa(OH)2 solutions (0.1% and 0.2%) in the presence or absence of organic materials (5% calf serum [CS]) at pH 12.6 were used to inactivate Salmonella Infantis and Salmonella Enteritidis in a reaction tube or on eggshells artificially contaminated with Salmonella Infantis. Both 0.1% and 0.2% FdCa(OH)2 were capable of inactivating Salmonella Infantis and Salmonella Enteritidis in liquid at >3 log10 colony-forming units (CFU)/ml within 3 and 1 min of contact time, respectively, even in the presence of 5% CS. Additionally, 0.1% and 0.2% FdCa(OH)2 reduced bacterial levels on contaminated eggshells to >3 log10 CFU/ml, within 3 and 1 min, respectively, in the presence of 5% CS. Without CS, 0.1% and 0.2% FdCa(OH)2 could reduce bacteria on eggshells to >3 log10 CFU/ml within 1 min and 30 sec, respectively. In contrast, 150 ppm NaOCl solution could not inactivate bacteria on eggshells down to >3 log10 CFU/ml within 3 min contact time, either with or without CS, and no bacterial reduction was observed in redistilled water. The findings of the present study indicate that FdCa(OH)2 solution has high efficacy against foodborne bacteria and may be a good candidate for enhancement of biosecurity at farms and egg processing plants.

Biological Change of Chemical States of Actinides and Lanthanides-effects of Organic Acids-

In this study, we have examined the chemical states change of lanthanides (Lns) of La, Ce, Pr, Eu, and actinides (Ans) of Th(IV), Pu(IV) in the complexes with organic acids of citric acids or desferrioxamine B (DFO) by the interaction with Pseudomonas fluorescens cells under the resting condition at pH 4 – 9. In the adsorption experiments the distribution coefficients (Kd) were determined. The oxidation states of Ce in the solution were determined by X-ray near edge fine structure (XAFS). In the absence of organic materials, Kd of Eu(III) increased gradually with pH up to 7; above 7, the Kd decreased with an increase in pH. In the presence of citric acid, we found that Kd was lower than that in the absence of organic materials, reflecting the formation of Eu(III)-citrate complexes competes with the Eu(III)-cell-surface complexes. For Ln-DFO complex, the higher Kds of La, Ce, and Pr were obtained at lower pHs on P. fluorescens cells. The Kd of Ce was lower than that of its neighboring REEs, La(III) and Pr(III). XAFS analysis showed that Ce exists as the Ce(IV)-DFO complex in higher pH than 6. Thus, the pH dependence of lower Kd of Ce is predominantly dependent on the stability of Ce(IV)-DFO complex. For the adsorption of Ans, the Kds of Th and Pu were larger than Eu, being inverse relationship to the stability constants of DFO complex. These results indicate that presence of organic acids affect the chemical states of Ln and An in the environments.

OSL chronology for lacustrine sediments recording high stands of Gahai Lake in Qaidam Basin, northeastern Qinghai–Tibetan Plateau

The Qaidam Basin in the northeastern Qinghai–Tibetan Plateau (QTP) is one of the largest hyper-arid intermontane basins in the northern hemisphere, and has abundant records for the study on palaeo-lake level fluctuations and palaeoclimatic changes. Significant efforts have been invested to define the timing of shoreline deposits using radiocarbon dating. However, due to the dating limit, the absence of organic materials and carbon reservoir effects for radiocarbon dating in arid areas, it is difficult to establish a reliable chronology for shoreline deposits. Therefore, controversy exists regarding the chronology for the high lake level in the Qaidam Basin, as well in the QTP. Some proposed that high lake levels occurred during late Marine Isotope Stage (MIS) 3, while others recently argued that the highest lake level in the QTP and adjacent regions existed in MIS 5. In Gahai Lake (now a salt lake), we investigated a section comprising lacustrine and shoreline deposits, which was about 25 m above the present lake level. Seven samples were collected for quartz optically stimulated luminescence (OSL) dating. A sample collected from a fine sand layer (the bottom of the section, and 12 m above the present lake level), which was assumed to have been deposited underwater, gave an OSL age of 82 ± 8 ka. It suggested that the lake level was at least 12 m higher than present in late MIS 5. The high lake level could maintain till about 73 ± 6 ka, and then decreased. This lake level decrease resulted in a gravel layer deposit between 73 ± 6 and 63 ± 6 ka (roughly during MIS 4). The lake level rose again (about 24 m above the present lake level) between 63 ± 6 and 55 ± 5 ka (roughly in early MIS 3). No lacustrine or shoreline deposits higher than the top of the current section were found around Gahai Lake. Thus, higher than present lake levels in Gahai Lake occurred in both late MIS 5 and early MIS 3.

Determination of trace organic carbon and nitrogen in the presence of carbonates in anorganic bovine bone graft materials

The widespread concern of bovine spongiform encephalopathy (mad cow disease) has raised questions about the possibility of residual organic material in bovine-derived bone graft materials. Conflicting reports have shown both the presence and the absence of organic materials in bone derived products. This study compared residual organic levels in two commercial bone graft products: a bovine bone product treated chemically and at low temperature, and a bovine bone product treated at high temperature. In this study, organic carbon, the primary constituent of organic materials, is defined as carbon that is not liberated as CO 2 upon acidification (i.e. non-carbonate carbon). Three approaches to the determination were used: (1) organic carbon was calculated as the difference between total carbon determined by high temperature combustion and carbonate carbon determined by acid evolution of CO 2. (2) Organic carbon was determined by measuring total carbon by high temperature combustion of a sample that had been pretreated with acid to remove all carbonate. (3) The total organic carbon remaining in solution after acid dissolution was determined. In addition, organic nitrogen was determined as the difference between total Kjeldahl and ammonia nitrogen. Total nitrogen values were confirmed using an instrumental nitrogen analyzer. No detectable organic carbon or organic nitrogen was observed in the high temperature bone product. In the low temperature treated bovine product, however, approximately 2000 μg/g organic carbon was measured by all three methods, as well as 15 μg/g organic nitrogen.

Composite suspended sediment particles and flocculation in glacial meltwaters: preliminary evidence from Alpine and Himalayan basins

AbstractResearch over the last decade has shown that the suspended sediment loads of many rivers are dominated by composite particles. These particles are also known as aggregates or flocs, and are commonly made up of constituent mineral particles, which evidence a wide range of grain sizes, and organic matter. The resulting in situ or effective particle size characteristics of fluvial suspended sediment exert a major control on all processes of entrainment, transport and deposition. The significance of composite suspended sediment particles in glacial meltwater streams has, however, not been established. Existing data on the particle size characteristics of suspended sediment in glacial meltwaters relate to the dispersed mineral fraction (absolute particle size), which, for certain size fractions, may bear little relationship to the effective or in situ distribution. Existing understanding of composite particle formation within freshwater environments would suggest that in‐stream flocculation processes do not take place in glacial meltwater systems because of the absence of organic binding agents. However, we report preliminary scanning electron microscopy data for one Alpine and two Himalayan glaciers that show composite particles are present in the suspended sediment load of the meltwater system. The genesis and structure of these composite particles and their constituent grain size characteristics are discussed. We present evidence for the existence of both aggregates, or composite particles whose features are largely inherited from source materials, and flocs, which represent composite particles produced by in‐stream flocculation processes. In the absence of organic materials, the latter may result solely from electrochemical flocculation in the meltwater sediment system. This type of floc formation has not been reported previously in the freshwater fluvial environment. Further work is needed to test the wider significance of these data and to investigate the effective particle size characteristics of suspended sediment associated with high concentration outburst events. Such events make a major contribution to suspended sediment fluxes in meltwater streams and may provide conditions that are conducive to composite particle formation by flocculation. Copyright © 2002 John Wiley & Sons, Ltd.

Chemical factors influencing the rates and sequences of silica phase transitions: Effects of organic constituents

Dissolved organic matter affects the solution chemistry, hence silica recrystallization reactions, in laboratory experiments. In the presence of organic matter, the reaction rates of silica phase transitions (opal-A to opal-CT) are reduced, and the opal-CT phase produced is more “ordered” (lower d(101) spacing) than that in the absence of organic materials. The degree of this decrease in d(101) spacing depends on the solution properties of the organic materials used in the experiments. The lower the pH of a solution and the higher its organic alkalinity, the slower the formation rate of opal-CT and the lower the d(101) spacing of the opal-CT phase that forms.

Studies of the Effects of Degradation Products on the Sorption of Tin and Radium

ABSTRACTThe effects on sorption on geological media caused by the presence of materials derived from a cementitious repository have been studied. This work includes an investigation of the influence of cellulosic degradation products on the sorption of tin and radium on London clay and Caithness flagstones and the sorption of radium as a function of calcium concentration.Experimental conditions were chosen to simulate those expected close to a cementitious repository (pH=l1) and at the edge of the zone of migration of the calcium plume (pH=8). Work was carried out, (i) under baseline conditions in the absence of organic materials; (ii) with gluconate, acting as a well-characterized organic degradation product simulant; (iii) with authentic cellulosic degradation products.This investigation has shown that the sorption of tin can be affected by the presence of cellulosic degradation products whereas the sorption of radium is little affected. The sorptive behaviour of radium is however strongly influenced by the calcium concentration.

Étude de l'activité virucide in vitro du dichloroisocyanurate de sodium

The virucidal activity of sodium dichloroisocyanurate (DCIC) towards poliovirus and vaccinia virus was studied in the presence or not of different organic loads using a new standard method. Results showed that, in the absence of organic materials, DCIC (1,000 and 100 μg/ml) was virucidal at 15 and at 30 min, respectively. Organic material strongly reduced the susceptibility of viruses to this product.

An introduction to biominerals and the role of organic molecules in their formation

The minerals of biology have two components, one of which is inorganic and the other organic. Understanding rests initially in the description of the factors that control the nucleation and growth of the inorganic components in the absence of organic materials, and in the study of the organic materials in the absence of the inorganic phase. Brief summaries of these studies are given and then an attempt is made to examine some of the interactive features of the whole mineral. There are very few generalizations that can be formulated yet since each mineral appears to be associated with the metabolic processes of a special cell. Partly, this is due to the diverse function that biominerals perform: supports, protection, sensors, storage and even homeostasis. We must also be aware of the vulnerable nature of precipitation control above the solubility limit. Many widespread medical problems involve the incorrect precipitation of iron and calcium compounds especially.