Non-toxic Chemicals Research Articles

Antibacterial Properties of Biodegradable Silver Nanoparticle Foils Based on Various Strains of Pathogenic Bacteria Isolated from the Oral Cavity of Cats, Dogs and Horses.

Frequent occurrence of microbial resistance to biocides makes it necessary to find alternative antimicrobial substances for modern veterinary medicine. The aim of this study was to obtain biodegradable silver nanoparticle-containing (AgNPs) foils synthesized using non-toxic chemicals and evaluation of their activity against bacterial pathogens isolated from oral cavities of cats, dogs and horses. Silver nanoparticle foils were synthesized using sodium alginate, and glucose, maltose and xylose were used as reducing agents. The sizes of AgNPs differed depending on the reducing agent used (xylose < maltose < glucose). Foil without silver nanoparticles was used as control. Bacterial strains were isolated from cats, dogs and horses by swabbing their oral cavities. Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli and extended-spectrum beta-lactamase (ESBL) producing E. coli were isolated on selective chromogenic microbiological media. The bactericidal effect of AgNPs foils obtained using non-toxic chemical compounds against E. coli, ESBL, S. aureus and MRSA isolated from oral cavities of selected animals was confirmed in this study. No statistically significant differences were observed between the foils obtained with different reducing agents. Therefore, all types of examined foils proved to be effective against the isolated bacteria.

SYNTHESIS AND CHARACTERIZATION OF COPPER OXIDE NANOPARTICLES USING AQUEOUS EXTRACT OF IRANIAN VIOLACEAE FLOWER

In this work, we have synthesized copper oxide nanoparticles using Iranian violaceae flower extract and explored its biological activity. Green synthesis has emerged as a reliable, sustainable and ecofriendly protocol for synthesizing a wide range of nanomaterials and hybrid materials. In this paper, we report the synthesis of Copper oxide nanoparticles by a simple biological route using the extract of Iranian violaceae flower and CuSO4, 5 H2O was used to synthesis the copper oxide Nanoparticles. The synthesized copper oxide nanoparticles were characterized using UV–visible spectroscopy, FTIR spectroscopy, FESEM, EDAX, and XRD techniques. UV –Visible analysis shows a characteristic peak around 266 nm for copper oxide nanoparticles and which is characteristic copper oxide nanoparticles. FTIR spectroscopy was used to characterize various capping and reducing agents present in the plant extract responsible for nanoparticle formation. The surface morphology was characterized using FESEM. The EDAX and XRD pattern suggested that prepared copper oxide nanoparticles were highly pure. The average particle size was calculated as 78.5 nm and α-copper oxide for all diffraction peaks (JCPDS card No. 41-1449) using the XRD technique. Our finding also support the synthesis of CuO NPs from Iranian violaceae flower sources due to relative abundance of plants for the production of reducing and stabilizing agents required for CuO NPs synthesis, potential efficiency of plant biomolecules in enhancing the toxicity effect of CuO NPs against microbes, prevention of environmental pollution due of nontoxic chemicals and degradation effectiveness of CuO NPs synthesized from plant sources. Furthermore, this study provides useful information on the rapid synthesis of CuO NPs with desired properties from plant extracts. Copper oxide NPs can have a good candidate for different applications.

Carboxylation of a Palladacycle Formed via C(sp3 )-H Activation: Theory-Driven Reaction Design.

Theory-driven organic synthesis is a powerful tool for developing new organic transformations. A palladacycle(II), generated from 8-methylquinoline via C(sp3 )-H activation, is frequently featured in the scientific literature, albeit that the reactivity toward CO2 , an abundant, inexpensive, and non-toxic chemical, remains elusive. We have theoretically discovered potential carboxylation pathways using the artificial force induced reaction (AFIR) method, a density-functional-theory (DFT)-based automated reaction path search method. The thus obtained results suggest that the reduction of Pd(II) to Pd(I) is key to promote the insertion of CO2 . Based on these computational findings, we employed various one-electron reductants, such as Cp*2 Co, a photoredox catalyst under blue LED irradiation, and reductive electrolysis ((+)Mg/(-)Pt), which afforded the desired carboxylated products in high yields. After screening phosphine ligands under photoredox conditions, we discovered that bidentate ligands such as dppe promoted this carboxylation efficiently, which was rationally interpreted in terms of the redox potential of the Pd(II)-dppe complex as well as on the grounds of DFT calculations. We are convinced that these results could serve as future guidelines for the development of Pd(II)-catalyzed C(sp3 )-H carboxylation reactions with CO2 .

Polyvinyl alcohol/alkyl ketene dimer films with excellent water resistance and water vapor barrier properties

Polyvinyl alcohol (PVA), a synthetic biodegradable polymer, is widely used in the packaging, textile, paper, and medical device industries. However, PVA presents critical limitations, such as poor water/moisture resistance and low water vapor barrier properties. Although chemical treatments have been used to overcome these problems, concerns about their toxicity still exist. Herein, alkyl ketene dimer (AKD), a non-toxic, cost-effective, and eco-friendly chemical, was used to improve the water resistance and water vapor barrier properties of PVA films. The water absorption and solubility of the PVA/AKD film with an AKD content of 10 wt% (PVA/AKD 10%) were 65.3 and 91.2% lower, respectively, than those of an untreated PVA film. In addition, the water vapor transmission rate of the PVA/AKD 10% film was found to be 58.1% of that of the untreated PVA film, indicating the superior water vapor barrier properties of the PVA/AKD film.

CONTEMPORARY ENDODONTIC OBTURATION TECHNIQUES: A COMPREHENSIVE LITERATURE REVIEW

The success of an endodontic treatment is excessively depends on obturation as well as irrigation. Hence, achiving a homogenious, impermeable and gap-free obturation plays a crucial role in endodontic treatment. Today, many materials and techniques have been developed for endodontic purpose such as those which applied with heat or vibration, those softened with non-toxic chemicals and those uses ultrasound energy. Some of these techniques are still preferred by proffessionals when some are abandoned. However, gutta-percha is the most used material either with or without sealer. Gutta-percha can be applied with cold or warm techniques. It’s known that warm gutta-percha technique leads a more homogenious obturation than cold techniques. Nevertheless, different obturation methods are convenient for different anatomic variations of root canal system. This review article summerize the contemporary and conventional obturation techniques with evaluation of their current status in endodontic implementation.

Non-Toxic Crosslinking of Electrospun Gelatin Nanofibers for Tissue Engineering and Biomedicine-A Review.

Electrospinning can be used to prepare nanofiber mats from diverse polymers, polymer blends, or polymers doped with other materials. Amongst this broad range of usable materials, biopolymers play an important role in biotechnological, biomedical, and other applications. However, several of them are water-soluble, necessitating a crosslinking step after electrospinning. While crosslinking with glutaraldehyde or other toxic chemicals is regularly reported in the literature, here, we concentrate on methods applying non-toxic or low-toxic chemicals, and enzymatic as well as physical methods. Making gelatin nanofibers non-water soluble by electrospinning them from a blend with non-water soluble polymers is another method described here. These possibilities are described together with the resulting physical properties, such as swelling behavior, mechanical strength, nanofiber morphology, or cell growth and proliferation on the crosslinked nanofiber mats. For most of these non-toxic crosslinking methods, the degree of crosslinking was found to be lower than for crosslinking with glutaraldehyde and other common toxic chemicals.

Comparison between modified LST Fastfloat and conventional HF methods for pollen preparation in highly minerogenic sediments

Pollen analysis is a commonly used method to interpret vegetation and environmental change. The standard pollen preparation technique in minerogenic sediments involves the use of hydrofluoric acid (HF) which is highly toxic. Currently the European legislation requires that hazardous chemicals should be substituted with less hazardous or non-toxic chemicals if possible. In the present paper the authors introduce a safer pollen preparation method, based on the use of low-toxic heavy liquid lithium heteropoly-tungstate (LST Fastfloat) and provide instructions for pollen preparation with the LSTFastflow method. Furthermore, five paired samples were processed from clayey and silty sediments with LST Fastfloat and conventional HF methods and the pollen and spore counting results obtained from these two methods were compared to test if there is statistically significant differences between the taxa. Calculation of the 95% confidence interval revealed statistical agreement in all studied taxa except one taxon in one sample pair. However, the study revealed systematic differences within two taxa, Betula and Pinus. Thus caution is needed when comparing results obtained by HF and heavy liquid (LST Fastfloat) methods.

Development of Latent Fingerprints on Non-Porous Surface with Fluorescent Dye Based Small Particle Reagent

Fingerprints are a useful source of evidence in establishing the identity of the person and hold large importance in crime scene investigations. A diverse range of physical and chemical methods are available for the development of latent fingerprints, but limited work is done on detection of prints from wet non-porous surfaces. The study aimed at developing a novel method for identification of latent fingerprints from such a type of surface. Small Particle Reagent was prepared using non-toxic chemicals and was proven to be effective in detecting latent fingerprints on Aluminum Foil. Fluorescent component, Basic Yellow-40 dye was used in the formulation. The Shelf life of the SPR solution was also considered an important factor in the study and was found to be 25 days.

CATMoS: Collaborative Acute Toxicity Modeling Suite.

Background:Humans are exposed to tens of thousands of chemical substances that need to be assessed for their potential toxicity. Acute systemic toxicity testing serves as the basis for regulatory hazard classification, labeling, and risk management. However, it is cost- and time-prohibitive to evaluate all new and existing chemicals using traditional rodent acute toxicity tests. In silico models built using existing data facilitate rapid acute toxicity predictions without using animals.Objectives:The U.S. Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) Acute Toxicity Workgroup organized an international collaboration to develop in silico models for predicting acute oral toxicity based on five different end points: Lethal Dose 50 ( value, U.S. Environmental Protection Agency hazard (four) categories, Globally Harmonized System for Classification and Labeling hazard (five) categories, very toxic chemicals [ ()], and nontoxic chemicals ().Methods:An acute oral toxicity data inventory for 11,992 chemicals was compiled, split into training and evaluation sets, and made available to 35 participating international research groups that submitted a total of 139 predictive models. Predictions that fell within the applicability domains of the submitted models were evaluated using external validation sets. These were then combined into consensus models to leverage strengths of individual approaches.Results:The resulting consensus predictions, which leverage the collective strengths of each individual model, form the Collaborative Acute Toxicity Modeling Suite (CATMoS). CATMoS demonstrated high performance in terms of accuracy and robustness when compared with in vivo results.Discussion:CATMoS is being evaluated by regulatory agencies for its utility and applicability as a potential replacement for in vivo rat acute oral toxicity studies. CATMoS predictions for more than 800,000 chemicals have been made available via the National Toxicology Program’s Integrated Chemical Environment tools and data sets (ice.ntp.niehs.nih.gov). The models are also implemented in a free, standalone, open-source tool, OPERA, which allows predictions of new and untested chemicals to be made. https://doi.org/10.1289/EHP8495

In vitro evaluation of the anti-diabetic potential of Helichrysum petiolare Hilliard & B.L. Burtt using HepG2 (C3A) and L6 cell lines.

Background:Helichrysum petiolare Hilliard & B.L. Burtt has been listed in a survey of plants used in traditional medicine for the treatment of type 2 diabetes in the Eastern Cape of South Africa. In this study, the antidiabetic potentials of ethanol, cold aqueous (CAQ) and boiled aqueous (BAQ) extracts of H. petiolare were investigated. Methods: The cytotoxic and glucose utilization effects of the extracts were evaluated using L6 myocytes and HepG2 (C3A) hepatocytes. α-amylase, α-glucosidase and lipase inhibition assays were also carried out. Results: The ethanol extract showed significant cytotoxic effects in the treated cells. Both BAQ and CAQ extracts significantly increased glucose uptake in L6 and C3A cell lines. The CAQ extract enhanced glucose uptake more in the L6 myocytes than in the C3A cell-lines hepatocytes. The BAQ extract showed higher levels of inhibition on α-amylase and α-glucosidase than CAQ. The activities were not significantly different from acarbose. However, BAQ showed lower lipase inhibition than acarbose (p<0.05). Conclusions: The BAQ and CAQ extracts of H. petiolare may, therefore, contain pharmacologically active and relatively non-toxic hypoglycaemic chemicals, which may be effective substitutes in the treatment of diabetes mellitus.

In vitro evaluation of the anti-diabetic potential of Helichrysum petiolare Hilliard & B.L. Burtt using HepG2 (C3A) and L6 cell lines

Background: Helichrysum petiolare Hilliard & B.L. Burtt has been listed in a survey of plants used in traditional medicine for the treatment of type 2 diabetes in the Eastern Cape of South Africa. In this study, the antidiabetic potentials of ethanol, cold aqueous (CAQ) and boiled aqueous (BAQ) extracts of H. petiolare were investigated. Methods: The cytotoxic and glucose utilization effects of the extracts were evaluated using L6 myocytes and HepG2 (C3A) hepatocytes. α-amylase, α-glucosidase and lipase inhibition assays were also carried out. Results: The ethanol extract showed significant cytotoxic effects in the treated cells. Both BAQ and CAQ extracts significantly increased glucose uptake in L6 and C3A cell lines. The CAQ extract enhanced glucose uptake more in the L6 myocytes than in the C3A cell-lines hepatocytes. The BAQ extract showed higher levels of inhibition on α–amylase and α-glucosidase than CAQ. The activities were not significantly different from acarbose. However, BAQ showed lower lipase inhibition than acarbose (p<0.05). Conclusions: The BAQ and CAQ extracts of H. petiolare may, therefore, contain pharmacologically active and relatively non-toxic hypoglycaemic chemicals, which may be effective substitutes in the treatment of diabetes mellitus.

Contributions to the kinetics of the iodide–iodate test reaction for micromixing time calculation with extended incorporation models

In order to characterize the efficiency of micromixing in chemical reactors, Villermaux used a borate buffer in the reaction system named after him. For micromixing time calculations, kinetic data of the Dushman reaction are essential. The choice of the acid and the influence of the salt on the reaction rate constant has led to a debate on the kinetics of the Dushman reaction. In the present work, a comprehensive kinetic study was performed to obtain the reaction rate equation of the Dushman reaction. A fifth-order rate equation with the partial reaction rate orders: H+2;IO3-1;I-2 could be confirmed.Furthermore, the influence of ionic strength μ was investigated using sodium perchlorate as the ion source. The reaction rate constant k for the Dushman reaction was determined as a function of the ionic strength k=k0·fDushmanlogfDushman=-1.93(±0.06)·μ1+μ+0.40±0.02·μ.The impact of the newly obtained reaction rate constant on micromixing time calculations was investigated using the incorporation model. It could be shown, that micromixing times can differ by a power of ten depending on the chosen reaction rate constant. Moreover, an extension of the incorporation model for sulphuric acid is provided, which includes the acid dissociation constants. This model unites the obtained reaction rate constant from this work and the equilibrium reactions of sulphuric acid. Micromixing experiments can now be performed independent of the acid choice, since similar micromixing times are calculated.According to the CLP Regulation and REACH, boric acid is classified as toxic for reproduction. Therefore, non-toxic chemicals have recently been preferred which has led to the implementation of a phosphate buffer by Pinot et al. and Baqueiro et al. This has risen questions about the definition of the segregation index and micromixing time calculations. Comprehensive micromixing time calculations have been performed with an extended incorporation model for a phosphate buffer. The results suggest that both HPO42- and H2PO4- species only take partially part in the acid–base reaction.

Complete degradation of tamoxifen using FeNi3@SiO2@ZnO as a photocatalyst with UV light irradiation: A study on the degradation process and sensitivity analysis using ANN tool

The present work aims to test degradation ability of FeNi3@SiO2@ZnO magnetic nanocomposite (FeNi3@SiO2@ZnO MNC) for Tamoxifen (TMX). The degradation process was accomplished through using photocatalytic reaction type under irradiation by UV light. The results of the characterization study demonstrated that FeNi3@SiO2@ZnO MNC possesses excellent practical and photocatalytic properties. In addition, it can be largely recyclable and effective for TMX degradation, where a complete degradation of 20 mg/L of TMX concentration can be achieved at the optimized conditions: pH = 7, FeNi3@SiO2@ZnO MNC dose = 0.005 g/L, and UV irradiation time = 120 min. Most of the by-products generated at the end of the TMX degradation reactions were in themselves non-toxic chemicals, including carbon dioxide, water, and mineral acids. The kinetic profiles of the degradation reaction were also of a fast pattern and could be mathematically represented by a pseudo-first-order formula. Ultimately, the analysis of ANN demonstrated that irradiation time had the greatest impact on the degradation process of TMX, hence pH and initial concentration. The study concluded that the photocatalytic process, using FeNi3@SiO2@ZnO MNC as a catalyst and under UV light irradiation, can be suggested as an efficacious method for the treatment of TMX wastewater in an economical, safe, and eco-friendly manner.

Tailoring strength of nanocellulose foams by electrostatic complexation

Supramolecular assembly of biobased components in water is a promising strategy to construct advanced materials. Herein, electrostatic complexation was used to prepare wet-resilient foams with improved mechanical property. Small-angle X-ray scattering and cryo-transmission electron microscopy experiments showed that suspensions with oppositely charged cellulose nanofibers are a mixture of clusters and networks of entangled fibers. The balance between these structures governs the colloidal stability and the rheological behavior of CNFs in water. Foams prepared from suspensions exhibited maximum compressive modulus at the mass composition of 1:1 (ca 0.12 MPa), suggesting that meaningful attractive interactions happen at this point and act as stiffening structure in the material. Besides the electrostatic attraction, hydrogen bonds and hydrophobic contacts may also occur within the clustering, improving the water stability of cationic foams. These results may provide a basis for the development of robust all- cellulose materials prepared in water, with nontoxic chemicals.

Simultaneous adsorption of heavy metals and organic dyes by β-Cyclodextrin-Chitosan based cross-linked adsorbent

Herein, a new adsorbent Nitrilotriacetic acid β-Cyclodextrin-Chitosan (NTA-β-CD-CS) was synthesized for the effective simultaneous removal of dyes and metals. In this process, the β-CD cavities captured Methylene blue (MB) by host/guest contacts, and the remaining functional groups were able to act as adsorption sites for metal ions and Methyl orange (MO). In the single process, the maximum adsorption capacities of NTA-β-CD-CS adsorbent toward the Hg (II) MB and MO were 178.3, 162.6, and 132.5 mg/g, respectively. Sips and Langmuir's model were appropriate to define the adsorption system and mechanism. Most prominently, the NTA-β-CD-CS adsorbent was highly effective in the simultaneous adsorption of metals and cationic dyes and remained consistent with the mono system. The adsorbent performance efficiency remained constant even after four cycles. Therefore, the advantages of non-toxic chemicals, excellent adsorption, and regeneration performance revealed that NTA-β-CD-CS possessed great potential to treat realistic and model wastewater from different industries.

Biosynthesis and Bio-sensing Applications of Silver and Gold Metal Nanoparticles

Biogenic nanoparticles have gained major interest because of their eco-friendly approach, as non-toxic chemicals are involved in the biosynthesis, and the preparation process carried out at ambient pressure and temperature. In the present study, two fungal strains (MM1and MM2) showed the ability to biosynthesize silver and gold nanoparticles, respectively, were isolated from local Egyptian soil samples. These two fungi were identified by the molecular technique 18srRNA as Aspergillus terreus isolate MM1-EGY and Aspergillus flavus isolate MM2-EGY. The biosynthesized silver nanoparticles by Aspergillus terreus isolate MM1-EGY exhibited UV absorbance around 420 nm and particle size range of 15-35 nm as measured by transmission electron microscopy (TEM). On the other hand, gold nanoparticles biosynthesized by Aspergillus flavus isolate MM2-EGY showed maximum UV/Vis absorbance around 550 nm and size range of 20-50 nm. The XRD of both AgNPs and AuNPS was constructed. The green synthesized gold nanoparticles were tested for sensitive and selective simultaneous voltammetric determination of neurotransmitter metabolite, vanillylmandelic acid (VMA) and homovanillic acids (HVA), while silver nanoparticles were applied for the fabrication of disposable screen-printed Ag/AgCl planner reference electrode.

Microelectrochemical Smart Needle for Real Time Minimally Invasive Oximetry.

A variety of brain disorders such as neural injury, brain dysfunction, vascular malformation, and neurodegenerative diseases are associated with abnormal levels of oxygen. Current methods to directly monitor tissue oxygenation in the brain are expensive and invasive, suffering from a lack of accuracy. Electrochemical detection has been used as an invasiveness and cost-effectiveness method, minimizing pain, discomfort, and injury to the patient. In this work, we developed a minimally invasive needle-sensor with a high surface area to monitor O2 levels in the brain using acupuncture needles. The approach was to directly etch the iron from stainless steel acupuncture needles via a controlled pitting corrosion process, obtaining a high microporous surface area. In order to increase the conductivity and selectivity, we designed and applied for the first time a low-cost coating process using non-toxic chemicals to deposit high surface area carbon nanoparticle, catalytically active laccase, and biocompatible polypyrrole. The physicochemical properties of the materials were characterized as well as their efficacy and viability as probes for the electrochemical detection of PO2. Our modified needles exhibited efficient electrocatalysis and high selectivity toward O2, with excellent repeatability. We well engineered a small diagnostic tool to monitor PO2, minimally invasive, able to monitor real-time O2 in vivo complex environments.

THz spectroscopic sensing of liquid chemicals using a photonic crystal fiber

A photonic crystal fiber based highly sensitive sensing mechanism is proposed, in the terahertz frequency band, able to detect a wide range of analytes, such as toxic or non-toxic chemicals and illicit drugs. The proper optimization of the PCF structure increases the light-matter interaction in the core, which results in a high relative sensitivity of about 94.0% with negligible confinement loss at the optimum frequency. Few liquids, chemicals, and drugs are considered to justify the sensing mechanism: a relative sensitivity of 99.60% can be achieved for the maximum porosity of core while ketamine was the analyte. Other fiber properties are also analyzed to check the feasibility of the proposed fiber with standard fiber and have obtained good performance. Therefore, the sensor may find applications to sense a wide range of analytes, non-toxic and toxic chemicals, as well as illicit drugs for example, in the THz region.

In vitro evaluation of the anti-diabetic potential of Helichrysum petiolare Hilliard & B.L. Burtt using HepG2 (C3A) and L6 cell lines.

Background:Helichrysum petiolare Hilliard & B.L. Burtt has been listed in a survey of plants used in traditional medicine for the treatment of type 2 diabetes in the Eastern Cape of South Africa. In this study, the antidiabetic potentials of ethanol, cold aqueous (CAQ) and boiled aqueous (BAQ) extracts of H. petiolare were investigated. Methods: The cytotoxic and glucose utilization effects of the extracts were evaluated using L6 myocytes and HepG2 (C3A) hepatocytes. α-amylase, α-glucosidase and lipase inhibition assays were also carried out. Results: The ethanol extract showed significant cytotoxic effects in the treated cells. Both BAQ and CAQ extracts significantly increased glucose uptake in L6 and C3A cell lines. The CAQ extract enhanced glucose uptake more in the L6 myocytes than in the C3A cell-lines hepatocytes. The BAQ extract showed higher levels of inhibition on α-amylase and α-glucosidase than CAQ. The activities were not significantly different from acarbose. However, BAQ showed lower lipase inhibition than acarbose (p<0.05). Conclusions: The BAQ and CAQ extracts of H. petiolare may, therefore, contain pharmacologically active and relatively non-toxic hypoglycaemic chemicals, which may be effective substitutes in the treatment of diabetes mellitus.

Efficient and green electrochemical synthesis of 4-aminophenol using porous Au micropillars

The development of new, efficient, chemoselective, and seemingly stable catalysts to rapidly convert 4-nitrophenol into 4-aminophenol, which is a particularly valuable chemical within multiple industries, is highly required. The use of non-toxic and non-corrosive chemicals for 4-aminophenol synthesis presents further challenges. We show a simple and scalable shape-controlled electrodeposition using a dual-template method for the synthesis of well-defined porous Au micropillar array electrodes to enhance electrocatalyst stability, efficiency, and durability during the electroreduction of 4-nitrophenol. Consequently, we avoid the use of toxic and aggressive chemical reducing agents and minimize the production of residues. Surface areas up to 55.2 m2 g−1 are achieved, which represent a substantial improvement over non-architectured Au film electrodes. Porous Au micropillars exhibit excellent yields (̴100 %), chemoselectivity (other byproducts are not detected), and a high kinetic constant of 2.5 × 10-2 min−1, which is impressively higher than those reported recently for Au thin films or Au-based electrocatalysts.