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Insects Mar 2022Ixodids (hard ticks), ectoparasitic arthropods that vector the causal agents of many serious diseases of humans, domestic animals, and wildlife, have become increasingly... (Review)
Review
Ixodids (hard ticks), ectoparasitic arthropods that vector the causal agents of many serious diseases of humans, domestic animals, and wildlife, have become increasingly difficult to control because of the development of resistance against commonly applied synthetic chemical-based acaricides. Resistance has prompted searches for alternative, nonconventional control tactics that can be used as part of integrated ixodid management strategies and for mitigating resistance to conventional acaricides. The quest for alternative control tactics has involved research on various techniques, each influenced by many factors, that have achieved different degrees of success. Alternative approaches include cultural practices, ingested and injected medications, biological control, animal- and plant-based substances, growth regulators, and inert desiccant dusts. Research on biological control of ixodids has mainly focused on predators, parasitoid wasps, infective nematodes, and pathogenic bacteria and fungi. Studies on animal-based substances have been relatively limited, but research on botanicals has been extensive, including whole plant, extract, and essential oil effects on ixodid mortality, behavior, and reproduction. The inert dusts kaolin, silica gel, perlite, and diatomaceous earth are lethal to ixodids, and they are impervious to environmental degradation, unlike chemical-based toxins, remaining effective until physically removed.
PubMed: 35323601
DOI: 10.3390/insects13030302 -
La Medicina Del Lavoro Jun 2020«Severe silicosis due to diatomaceous earth in dental alginate: a necropsy study»
UNLABELLED
«Severe silicosis due to diatomaceous earth in dental alginate: a necropsy study»
BACKGROUND:
METHODS:
A commercial sample of calcinated diatomaceous earth and necroscopic lung samples were analysed by scanning electron microscopy (SEM-EDS) and X-ray diffraction (XRD) for the quali-quantitative determination of crystalline silica. Material safety data sheets (MSDSs) of diatomaceous earth produced in 2002 and 2018 were examined to assess the information content on silicosis risk. Clinical findings and post-mortem examinations of the worker are evaluated.
RESULTS:
A cristobalite concentration of 36% (wt/wt) was determined in the diatomaceous earth sample and a large amount of diatom fragments were observed in lung samples. The DRX spectra indicated the presence of cristobalite either in the bulk sample or in the lung tissues. The MSDS dated 2002 reported the presence of SLC up to 63% with cristobalite concentrations <60%, and the resulting risk of silicosis, while the MSDS dated 2018 and referred to a commercial product currently on the market indicated a concentration of cristobalite <1% and no risk of silicosis. The worker was suffering from a severe silicosis, histologically confirmed by necropsy.
CONCLUSION:
The present case-study revealed that the risk of silicosis from calcined diatomaceous earths used to produce dental alginates has been ignored. The lack of engineering controls and personal protection measures led to a high cristobalite lung burden, consistent with the development of a severe silicosis that were a contributing factor of death. A MSDS of a commercial product currently on the market does not report this serious hazard.
Topics: Alginates; Diatomaceous Earth; Humans; Occupational Exposure; Silicon Dioxide; Silicosis
PubMed: 32624564
DOI: 10.23749/mdl.v111i3.9742 -
Materials (Basel, Switzerland) May 2022The fractionation of diatomaceous earth (DE) using sedimentation made it possible to obtain separate unbroken diatom fractions from broken or agglomerated bodies with a...
The fractionation of diatomaceous earth (DE) using sedimentation made it possible to obtain separate unbroken diatom fractions from broken or agglomerated bodies with a range of particle sizes. The produced filler was used to prepare polylactide (PLA)/diatomaceous earth biocomposite samples containing different particle sizes, which were subjected to mechanical testing (tensile strength, flexural strength, impact strength), colloidal testing (contact angle, color change test, SEM/EDS), and thermal testing (TGA, DSC, DMA). Modification of the PLA containing the smallest particle size with diatomaceous earth (Fraction 5) resulted in a higher impact strength compared to both the pure PLA and the PLA/DE composite that contained base diatomaceous earth. Furthermore, the melt flow rate was improved by more than 80 and 60% for the composite modified with fractionated diatomaceous earth (Fraction 4) compared to pure PLA and base diatomaceous earth, respectively. The elasticity of the composite was also improved from 3.3 GPa for pure polylactide to 4.4 GPa for the system containing the smallest diatomaceous earth particles (Fraction 5).
PubMed: 35629631
DOI: 10.3390/ma15103607 -
RSC Advances Sep 2021The present article overviews the current state-of-the-art and future prospects for the use of diatomaceous earth (DE) in the continuously expanding sector of energy... (Review)
Review
The present article overviews the current state-of-the-art and future prospects for the use of diatomaceous earth (DE) in the continuously expanding sector of energy science and technology. An eco-friendly direct source of silica and the production of silicon, diatomaceous earth possesses a desirable nano- to micro-structure that offers inherent advantages for optimum performance in existing and new applications in electrochemistry, catalysis, optoelectronics, and biomedical engineering. Silica, silicon and silicon-based materials have proven useful for energy harvesting and storage applications. However, they often encounter setbacks to their commercialization due to the limited capability for the production of materials possessing fascinating microstructures to deliver optimum performance. Despite many current research trends focusing on the means to create the required nano- to micro-structures, the high cost and complex, potentially environmentally harmful chemical synthesis techniques remain a considerable challenge. The present review examines the advances made using diatomaceous earth as a source of silica, silicon-based materials and templates for energy related applications. The main synthesis routes aimed at preserving the highly desirable naturally formed neat nanostructure of diatomaceous earth are assessed in this review that culminates with the discussion of recently developed pathways to achieving the best properties. The trend analysis establishes a clear roadmap for diatomaceous earth as a source material of choice for current and future energy applications.
PubMed: 35495528
DOI: 10.1039/d1ra05810j -
Materials (Basel, Switzerland) Oct 2022The presented research is focused on the complex assessment of three different types of diatomaceous earth and evaluation of their ability for application as pozzolana...
The presented research is focused on the complex assessment of three different types of diatomaceous earth and evaluation of their ability for application as pozzolana active admixtures applicable in the concrete industry and the production of repair mortars applicable for historical masonry. The comprehensive experimental campaign comprised chemical, mineralogical, microstructural, and physical testing of raw materials, followed by the analyses and characterization of pozzolanic activity, rheology and heat evolution of fresh blended pastes, and testing of macrostructural and mechanical parameters of the hardened 28-days and 90-days samples. The obtained results gave evidence of the different behavior of researched diatomaceous earth when mixed with water and Portland cement. The differences in heat evolution, initial and final setting time, porosity, density, and mechanical parameters were identified based on chemical and phase composition, particle size, specific surface, and morphology of diatomaceous particles. Nevertheless, the researched mineral admixtures yielded a high strength activity index (92.9% to 113.6%), evinced their pozzolanic activity. Three fundamental factors were identified that affect diatomaceous earth's contribution to the mechanical strength of cement blends. These are the filler effect, the pertinent acceleration of OPC hydration, and the pozzolanic reaction of diatomite with Portland cement hydrates. The optimum replacement level of ordinary Portland cement by diatomaceous earth to give maximum long-term strength enhancement is about 10 wt.%., but it might be further enhanced based on the properties of pozzolan.
PubMed: 36234222
DOI: 10.3390/ma15196881 -
Pest Management Science Jul 2024Wheat grain containers or silos can be perfect habitats for insects, which generate large economic losses to grain production. Natural alternatives to synthetic...
BACKGROUND
Wheat grain containers or silos can be perfect habitats for insects, which generate large economic losses to grain production. Natural alternatives to synthetic insecticides have grown in popularity because of health, economic and ecological issues. Diatomaceous earth is a natural compound that has an insecticide effect by enhancing an insect's dehydration with no toxicity on mammals including humans. The aim of this study is to confirm the effect of diatomaceous earth as an insecticide for the wheat grain pest, the red flour beetle Tribolium castaneum (Coleoptera: Tenebrionidae) and demonstrate its underlying mechanisms as an insecticide by open-flow respirometry and scanning electron microscopy.
RESULTS
Survival bioassays of T. castaneum revealed a dose-dependent insecticide effect of diatomaceous earth. Gravimetric measurements showed that 2 days exposure to diatomaceous earth produces a significant increase of mass loss. Open-flow respirometry measurements showed an increase of total water emission rate on insects due to an increase of both, respiratory and cuticular water loss. Our study revealed that diatomaceous earth produces an increase of insect's cuticle permeability, which is responsible for elevated cuticular water loss. Scanning electron microscopy images provided visual evidence of the lipid absorbent properties of diatomaceous earth particles, and showed a tendency for higher, although not significant, damaged area of the cuticle's surface from diatomaceous earth treated insects compared to control ones.
CONCLUSION
With state-of-the art techniques like open-flow respirometry and scanning electron microscopy, we demonstrated the underlying mechanism of diatomaceous earth as an insecticide and provided new cues for understanding the properties of the cuticle and its ecological importance. © 2024 Society of Chemical Industry.
Topics: Animals; Diatomaceous Earth; Insecticides; Tribolium; Microscopy, Electron, Scanning
PubMed: 38372489
DOI: 10.1002/ps.8033 -
Insects Sep 2020Diatomaceous earth (DE) has long been known as a potential protectant for stored cereals against various stored product insects. Despite favorable effect for the...
Diatomaceous earth (DE) has long been known as a potential protectant for stored cereals against various stored product insects. Despite favorable effect for the environment and human health, DE has some negative side effects on the treated commodity. In order to minimize negative response and to improve its efficacy, this paper represents a study of developed natural formulation based on DE SilicoSec enhanced with botanicals (essential oil lavender, corn oil, and bay leaves dust) and silica gel. The activity of formulation (labeled as N Form) was tested against (L.) (F.), and (Herbst) in seed wheat and barley under controlled conditions. As a reference comparative value, DE SilicoSec was used. N Form showed higher efficacy than DE, especially in barley at the lowest concentration, inducing higher mortality of all three insect species. The highest average progeny inhibition was recorded in population both in seed wheat and barley with 94.9% and 96.3% of inhibition, respectively, followed with and inhibition of 90.6% and 86.1%, respectively, in wheat and 94.9% and 89.7%, respectively, in barley. Results indicate that the developed natural formulation N Form enhanced the activity of DE SilicoSec using lower amount of DE dust and that it could be successfully implemented for storage of cereals as alternatives to chemical pesticides for stored product insect control.
PubMed: 32911831
DOI: 10.3390/insects11090613 -
Pest Management Science Jun 2024Over the past two decades, bed bugs (Cimex spp.) have resurged as common urban pests around the world. The search for efficient and safe control measures has become a...
BACKGROUND
Over the past two decades, bed bugs (Cimex spp.) have resurged as common urban pests around the world. The search for efficient and safe control measures has become a key interest among researchers, manufacturers, and pest control professionals. In this study, we evaluated and compared the efficacy of steam, diatomaceous earth (DE) dust, and a combination of both against tropical bed bugs (Cimex hemipterus (F.)) under laboratory and field conditions.
RESULTS
In the laboratory study, the mortality of bed bugs after 2 days of exposure to DE dust was 100%. When bed bugs stayed on the surface of an object or in cracks, a brief steam treatment (1 s) caused 100% mortality. However, when bed bugs were hidden under a fabric cover, steam application for 10 s only caused 89 ± 6% mortality. Bed bugs that survived steam treatment exhibited reduced feeding activity. In a 14-week long study, there was no significant difference in the reduction rate of bed bugs between steam treatment and DE dust treatment. A 37-week long control study showed that steam and steam plus DE dust treatments eliminated 97-100% of the infestations.
CONCLUSION
Applying steam and DE dust are effective strategies for eliminating natural tropical bed bug infestations. Continuous follow-up monitoring and treatment until no bed bugs are found are crucial in completely eliminating the infestation of tropical bed bugs. © 2024 Society of Chemical Industry.
PubMed: 38847149
DOI: 10.1002/ps.8227 -
Journal of the Mechanical Behavior of... Sep 2022The effect of a natural filler (diatomaceous earth [DE], a promising drug-delivery agent) and its content was investigated on the performance of a model glass-ionomer...
The effect of a natural filler (diatomaceous earth [DE], a promising drug-delivery agent) and its content was investigated on the performance of a model glass-ionomer cement (GIC). Three sample series, differing in DE content (0, 2.5 and 5 wt%), were prepared using a commercial GIC as a matrix (3M Ketac Molar Easymix). The resultant surface microhardness and roughness, wear performance, and compressive strength of the samples were measured after the samples had been stored in deionized water at 37°C for a fixed time. Moreover, the film thickness was tested for the freshly mixed samples. The numerical data was subjected to statistical analysis, in order to test the null hypotheses of the equality of the measured properties between the reference and the DE-modified samples. According to the results, diatomaceous earth particles are uniformly distributed in the GIC matrix, and the cavities of frustules tend to be filled with the GIC. This translates into the observed performance of the DE-loaded GIC. Compared with the reference material (0 wt% DE), the surface microhardness (2.5 wt% DE, p = 0.014; 5 wt% DE, p = 0.005) and roughness (e.g. Ra; 2.5 wt% DE, p = 0.003; 5 wt% DE, p < 0.001) are increased. No effect on the wear performance (p = 0.530 and 0.256, respectively) or compressive strength (p = 0.514) was noticed in the case of DE partially substituting the glass phase. Based on the study results, it is evidenced that diatom frustules are a suitable filler for application in conventional glass-ionomer cements as the glass-substituting drug-loaded carrier. Notably, however, the surface finish method of the DE-filled materials needs development.
Topics: Compressive Strength; Diatomaceous Earth; Drug Carriers; Glass Ionomer Cements; Materials Testing
PubMed: 35738132
DOI: 10.1016/j.jmbbm.2022.105324 -
Toxicology of diatomaceous earth, phyto oils and their admixed emulsions against adults of (Herbst).Toxicology Reports 2022(Herbst), one of the invasive stored pest, is resistant to the most of synthetic insecticides used against this it. Moreover, synthetic insecticides are a major threat...
(Herbst), one of the invasive stored pest, is resistant to the most of synthetic insecticides used against this it. Moreover, synthetic insecticides are a major threat to human health, the environment, and the ecosystem. The development of some smart tools is needed to minimize the use of hazardous chemicals. As an alternative, nano-insecticides are on the horizon. Emulsions are expressed as sustain release of insecticidal components to achieve maximum efficacy and low residual toxicity. In this study, some essential oils ( (DC.) Stapf, L., L., and L.), diatomaceous earth (DE), and their nano-emulsions are evaluated against . Essential oils and DE were tested at four (60 ppm, 30 ppm, 15 ppm, 7.5 ppm) different concentrations with and without emulsions, and data was recorded after 6, 12, 24, 48, and 72 h of exposure respectively. The mortality observed in essential oils of , , and without emulsion after 72 h of treatment at the highest concentration was 98%, 95%, and 85%, respectively. While, at the highest concentration the lowest mortalities were observed with DE and i.e. 65%. Insecticidal activity of emulsion essential oils increased to 100%, 98%, 90%, and 68.3% for , , , and , respectively. The results support that these admixed emulsions could be used as an alternative to synthetic insecticides in conventional formulations.
PubMed: 36518385
DOI: 10.1016/j.toxrep.2022.05.011