Earth Dust Research Articles

Efficacy of steam and diatomaceous earth dust against the tropical bed bug Cimex hemipterus (F.) under laboratory and field conditions.

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. 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. 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.

Effect of Diatomaceous Earth (DE) Against the Stored Product Beetles, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) under Laboratory Conditions

Studies on the control of the saw-toothed grain beetle Oryzaephilus surinamensis with a commercial formulation of the Diatomaceous Earth or diatomite (D); (silicon dioxide made up of fossilised diatoms) were carried out at the Entomology Laboratory at a relative humidity of 50 ± 5%, and ambient temperature of 28 ± 2 °C. Laboratory experiments were applied to assess the efficacy of Diatomaceous Earth dust; silicon dioxide commercially on 2nd-5th instar larvae and adults of O. surinamensis. Three concentrations of Diatomaceous Earth (DE) were weighed (2, 3, and 4 grams), and each concentration was mixed with 100 grams of amber rice grains. Beetles were fed on amber rice grains treated with (DE). The results showed that Diatomaceous Earth (DE) was significantly effective at all tested concentrations after 7 days post-treatment. Nevertheless, susceptibility showed visible significant differences in the mortality level on the last day of the tests between adults, 2nd, 5th instar larvae which were treated with three (DE) concentrations. Adults were least susceptible, while 2nd and 5th instar larvae were most susceptible to DE. All Diatomaceous Earth (DE) was significant and more effective on insect life at a higher concentration of 4 g/100 kg, where the mortality proportion was 100%, 99.50% for 2nd, and 5th instar larvae, respectively, and 97.50% for an adult after 5 days post-treatment. However, all O. surinamensis life stages’ mortality percentages reached 100% after 7 days post-treatment. Consequently, due to the effectiveness of this Diatomaceous Earth on different life stages of O. surinamensis, they could be recommended for the management of this insect. Furthermore, to achieve more effective control over this beetle, formulation of the Diatomaceous Earth (DE); Silicon dioxide, could be used since it appeared to be most effective and consistence in its action against different life stages of the beetle. Lastly, the possibility of using Diatomaceous earth to manage stored-product insects has been debated.

A Case Study on Tropical Bed Bug, Cimex hemipterus (Hemiptera: Cimicidae) Infestation and Management in Dormitories.

Numerous bed bug research papers have been published in the past 20 yr as a result of bed bug (Cimex spp.) (Hemiptera: Cimicidae) resurgence in the world. Yet, few of them focused on the management of the tropical bed bug, C. hemipterus (F.). Here, we describe a case of tropical bed bug infestation in two dormitory buildings and effectiveness of a tropical bed bug treatment program. The study site consisted of 125 dormitories in two buildings. An initial building-wide monitoring with ClimbUp interceptors revealed 25 infestations. The spatial distribution of bed bug infested rooms showed a significant aggregated distribution pattern with same infestation status for neighboring units sharing walls. All infested rooms were monitored every 2 wk and treated using a combination of steam and diatomaceous earth (DE) dust application if bed bugs were still found. For the 25 initially identified infested rooms, after 14 wk treatment, 44% of them no longer had bed bugs, and the mean number of bed bugs captured per room decreased by 94.1%. A combination of steam and DE dust treatment is an effective strategy for suppressing tropical bed bug infestations in dormitory environment.

Measuring contamination levels in external induced atmosphere of Russian orbital stations and the Russian Segment of the International Space Station

In view of the increasing number of science experiments being carried out in the Russian Segment of the International Space Station, there is a growing interest in the state of the environment where they are conducted, especially, in the contaminating effects of the external induced atmosphere. Sources of the induced atmosphere contamination are the off-gassing of non-metallic materials of the outer coatings, firings of control system thrusters and exhausts of various venting systems, as well as dust particles remaining on the external surfaces after launch from Earth, atmospheric aerosols and space dust. The paper presents results of measurements of molecular depositions on the sensors of quartz crystal microbalances that were used for evaluating contamination in the induced atmosphere of the first Soviet orbital stations Salyut-7 and Mir, as well as modules Pirs and Poisk of the Russian Segment of the International Space Station. The results of the experiments show a significant effect of lighting and thermal conditions of the contamination source and the quartz microbalance sensor on the measurement results. Key words: contamination, quartz crystal microbalance, orbital, external induced atmosphere.

Measuring contamination levels in external induced atmosphere of Russian orbital stations and the Russian Segment of the International Space Station

In view of the increasing number of science experiments being carried out in the Russian Segment of the International Space Station, there is a growing interest in the state of the environment where they are conducted, especially, in the contaminating effects of the external induced contamination are firings of control as dust particles the outgassing system thrusters remaining on atmosphere. Sources of the induced atmosphere of non-metallic materials of the outer coatings, and exhausts the external of various venting systems, as well surfaces after launch from Earth, atmospheric aerosols and space dust. The paper presents results of quartz crystal microbalances molecular depositions measurements that were used for evaluating contamination in the induced atmosphere of the first Soviet orbital stations Salyut-7 and Mir, as well as modules Pirs and Poisk of the Russian Segment of the International Space Station. The results of the experiments show a significant effect of illumination and thermal conditions of the contamination source and the quartz microbalance sensor on the measurement results.

Determination of heavy metal content in dust of earth's surface and dust on air conditioner filter by X-ray fluorescence analysis

The dust of earth's surface and the dust on air conditioner filters reflect a certain area of air pollution in a period of time. In the present study, we investigate the dust collected from the Wangjiang campus of Sichuan University on March, 2017. The dust is divided into 9 groups according to their diameters. The dust is made into the samples by mixing the dust and analytically pure starch at a ratio of 1:2, and pressing it into slices of 1.5 cm in radius and 6 mm in thickness through using a powder compressor. Likewise, the salts (MnSO4H2O, Fe(NO3)39H2O, CuSO45H2O, ZnSO47H2O, Pb(NO3)2), are also made into standard samples of different elements (Mn, Fe, Cu, Zn, and Pb). X-ray fluorescence analyzer is used to measure the element content in each of the samples according to calibration curves measured from the standard samples. The results show that the content of each element in the earth's surface dust is lower than that in the dust on the air conditioner filter. The values of Cu, Zn, and Pb content in the dust are higher than the average content of the topsoil in Sichuan Province, China. These elements possibly originate from motor vehicle exhaust. Based on the theoretical model for the gaseous elements to change into the fine particulate matter, the change of the trace element content with the particle size can be expressed as Ci kiDn, where Ci is the content of the metal element i in the dust, ki is a scale factor, D is the diameter of the dust particle, and n is the distribution index. From the results it is concluded that the distribution indexes corresponding to various elements are approximately the same in the size range of interest to us (32.5-230 m). A recommended value of n is -0.430.06.

Exposure and analysis of microparticles embedded in silica aerogel keystones using NF3‐mediated electron beam–induced etching and energy‐dispersive X‐ray spectroscopy

AbstractIn 2006, NASA's Stardust spacecraft delivered to Earth dust particles collected from the coma of comet 81P/Wild 2, with the goal of furthering the understanding of solar system formation. Stardust cometary samples were collected in a low‐density, nanoporous silica aerogel making their study technically challenging. This article demonstrates the identification, exposure, and elemental composition analysis of particles analogous to those collected by NASA's Stardust mission using in‐situ SEM techniques. Backscattered electron imaging is shown by experimental observation and Monte Carlo simulation to be suitable for locating particles of a range of sizes relevant to Stardust (down to submicron diameters) embedded within silica aerogel. Selective removal of the silica aerogel encapsulating an embedded particle is performed by cryogenic NF3‐mediated electron beam–induced etching. The porous, low‐density nature of the aerogel results in an enhanced etch rate compared with solid material, making it an effective, nonmechanical method for the exposure of particles. After exposure, elemental composition of the particle was analyzed by energy‐dispersive X‐ray spectroscopy using a high spectral resolution microcalorimeter. Signals from fluorine contamination are shown to correspond to nonremoved silica aerogel and only in residual concentrations.

Posttreatment Feeding Affects Mortality of Bed Bugs (Hemiptera: Cimicidae) Exposed to Insecticides.

Insecticide sprays and dusts are used for controlling bed bugs, Cimex lectularius L. In natural environments, bed bugs have daily access to hosts after they are exposed to insecticides. The established laboratory insecticide bioassay protocols do not provide feeding after insecticide treatments, which can result in inflated mortality compared with what would be encountered in the field. We evaluated the effect of posttreatment feeding on mortality of bed bugs treated with different insecticides. None of the insecticides tested had a significant effect on the amount of blood consumed and percent feeding. The effect of posttreatment feeding on bed bug mortality varied among different insecticides. Feeding significantly reduced mortality in bed bugs exposed to deltamethrin spray, an essential oil mixture (Bed Bug Fix) spray, and diatomaceous earth dust. Feeding increased the mean survival time for bed bugs treated with chlorfenapyr spray and a spray containing an essential oil mixture (Ecoraider), but did not affect the final mortality. First instars hatched from eggs treated with chlorfenapyr liquid spray had reduced feeding compared with nymphs hatched from nontreated eggs. Those nymphs hatched from eggs treated with chlorfenapyr liquid spray and successfully fed had reduced mortality and a higher mean survival time than those without feeding. We conclude that the availability of a bloodmeal after insecticide exposure has a significant effect on bed bug mortality. Protocols for insecticide efficacy testing should consider offering a bloodmeal to the treated bed bugs within 1 to 3 d after treatment.

Impact of Martian and Lunar dust simulants on cellular inflammation in human skin wounds ex vivo

In 2006 NASA published its plans to build a manned lunar station in order to undertake missions to Mars in the future. Thus research projects have been conducted on the influence of Lunar and Martian dust on human health. The present study investigated the effect of Lunar and Martian dust simulants (LDS, MDS) in comparison with earth dust (ED) on viability, migration and inflammatory reaction during wound closure in an ex vivo human skin wound model. 6 mm full-thickness skin explants, with a central 3 mm epidermal wound were cultured with LDS, MDS or ED for 4 and 8 days and compared to wound closure without dust exposure. Tissue and conditioned medium were submitted to histological, immunohistochemical (Ki67, Caspase-3) and biochemical analyses (hydroxyproline assay, zymography, IL-6, TNF-α and TGF-β ELISA). All dusts increased proinflammatory markers with significant increases in MDS-treated samples (IL-6: p<0.05; MMP-9: p<0.005) and reduced MMP-2 (p<0.05) compared to no dust controls over time. No significant differences were found regarding wound closure, proliferation, apoptosis and tissue degradation. Highly oxidative Martian dust may cause increased cutaneous inflammation. As is currently advocated for wounds contaminated with earth dust, surgical wound debridement should be performed to ensure uncompromised wound healing.

Effectiveness of a Reduced-Risk Insecticide Based Bed Bug Management Program in Low-Income Housing.

Bed bug (Cimex lectularius L.) infestations are becoming increasingly common in low-income communities. Once they are introduced, elimination is very difficult. As part of the efforts to develop effective and safe bed bug management programs, we conducted a laboratory study evaluating the efficacy of a reduced-risk insecticide—Alpine aerosol (0.5% dinotefuran). We then conducted a field evaluation of a reduced-risk insecticide based integrated pest management (IPM) program in low-income family apartments with young children. In laboratory evaluations, direct spray and 5 min exposure to dry Alpine aerosol residue caused 100.0 ± 0.0 and 91.7 ± 8.3% mortality to bed bug nymphs, respectively. Direct Alpine aerosol spray killed 91.3 ± 4.3% of the eggs. The IPM program included education, steam, bagging infested linens, placing intercepting devices under furniture legs and corners of rooms, applying Alpine aerosol and Alpine dust (0.25% dinotefuran, 95% diatomaceous earth dust), and regularly scheduled monitoring and re-treatment. Nine apartments ranging from 1–1,428 (median: 29) bed bugs based on visual inspection and Climbup interceptor counts were included. Over a 6-month period, an average 172 g insecticide (Alpine aerosol + Alpine dust) was used in each apartment, a 96% reduction in pesticide usage compared to chemical only treatment reported in a similar environment. The IPM program resulted in an average of 96.8 ± 2.2% reduction in the number of bed bugs. However, elimination of bed bugs was only achieved in three lightly infested apartments (<30 bed bugs at the beginning). Elimination success was closely correlated with the level of bed bug populations.

Retrieval of aerosol single-scattering albedo and polarized phase function from polarized sun-photometer measurements for Zanjan's atmosphere

Abstract. The polarized phase function of atmospheric aerosols has been investigated for the atmosphere of Zanjan, a city in northwest Iran. To do this, aerosol optical depth, Ångström exponent, single-scattering albedo, and polarized phase function have been retrieved from the measurements of a Cimel CE 318-2 polarized sun-photometer from February 2010 to December 2012. The results show that the maximum value of aerosol polarized phase function as well as the polarized phase function retrieved for a specific scattering angle (i.e., 60°) are strongly correlated (R = 0.95 and 0.95, respectively) with the Ångström exponent. The latter has a meaningful variation with respect to the changes in the complex refractive index of the atmospheric aerosols. Furthermore the polarized phase function shows a moderate negative correlation with respect to the atmospheric aerosol optical depth and single-scattering albedo (R = −0.76 and −0.33, respectively). Therefore the polarized phase function can be regarded as a key parameter to characterize the atmospheric particles of the region – a populated city in the semi-arid area and surrounded by some dust sources of the Earth's dust belt.

Light scattering from diatomaceous earth aerosol

The light scattering and extinction properties of mineral aerosol are strongly affected by dust particle shape. In this work, scattering phase function and polarization profiles of diatomaceous earth aerosol are measured at a wavelength of 550nm, and the results are compared to T-matrix theory based simulations using uniform spheroid models for the particle shape. The particle shape distribution is determined by spectral fitting of the experimental infrared (IR) extinction spectral line profile for diatomaceous earth dust. It is found that a particle shape model that peaks toward both extreme rod-like and disk-like shapes results in the best fits to the IR spectral data. This particle shape model is then used as a basis for modeling the visible light scattering properties. While the visible simulations show only modestly good agreement with the data, the fits are generally better than those obtained using more commonly invoked particle shape distributions.

EFFECTIVENESS OF SOME PLANT DUSTS AND INSECTICIDES AGAINST LESSER GRAIN BORER-RHIZOPERTHA DOMINICA (F) (COLEOPTERA: BOSTRYCHIDAE)

The aim of this study was to investigatethe efficacy of some plant dusts i.e. black pepper seeds dust (Piper nigrum L.); Cloves flowering buds (Syzegium aromaticum); Chili fruits dust (Capsicum frutescens); Cinnamon dust (Cinnamonum zeylanicum); Diatomaceous earth (DE) dust in comparison with katel-sous dust against Rhizopertha dominica (F.) at 30+1oC and 65+5% RH, also the efficacy of two organophosphorus insecticides namely malathion and piromiphos –methyl (Actellic) and one botanical insecticide (Neemazal T/S 1% Azadirachtin) was evaluated. The results indicated that adult mortality was concentration and exposure period dependent. Adult mortality was increased with increasing the dust concentration and exposure period. The results of the various dusts against Rhizopertha dominica adults indicated that DE was the most effective followed by black pepper dust, cloves flowering dust, katel-sous dust and chili dust which was the least effective one. On the other hand the highest tested cinnamon dust concentration (6% w/w) resulted a lower mortality (less than 40%) even after two weeks from treatment. Results of the toxicity index of the various tested insecticides against Rhizopertha dominica (F.), revealed that Actellic was the most effective followed by Malathion and Neemazal which was the least effective one.

Evaluation of Two Least Toxic Integrated Pest Management Programs for Managing Bed Bugs (Heteroptera: Cimicidae) With Discussion of a Bed Bug Intercepting Device

The cost and effectiveness of two bed bug (Cimex lectularius L.) integrated pest management (IPM) programs were evaluated for 10 wk. Sixteen bed bug-infested apartments were chosen from a high-rise low-income apartment building. The apartments were randomly divided into two treatment groups: diatomaceous earth dust-based IPM (D-IPM) and chlorfenapyr spray-based IPM (S-IPM). The initial median (minimum, maximum) bed bug counts (by visual inspection) of the two treatment groups were 73.5 (10, 352) and 77 (18, 3025), respectively. A seminar and an educational brochure were delivered to residents and staff. It was followed by installing encasements on mattresses and box springs and applying hot steam to bed bug-infested areas in all 16 apartments. Diatomaceous earth dust (Mother Earth-D) was applied in the D-IPM group 2 d after steaming. In addition, bed bug-intercepting devices were installed under legs of infested beds or sofas or chairs to intercept bed bugs. The S-IPM group only received 0.5% chlorfenapyr spray (Phantom) after the nonchemical treatments. All apartments were monitored bi-weekly and retreated when necessary. After 10 wk, bed bugs were eradicated from 50% of the apartments in each group. Bed bug count reduction (mean +/- SEM) was 97.6 +/- 1.6 and 89.7 +/- 7.3% in the D-IPM and S-IPM groups, respectively. Mean treatment costs in the 10-wk period were $463 and $482 per apartment in the D-IPM and S-IPM groups, respectively. Bed bug interceptors trapped an average of 219 +/- 135 bed bugs per apartment in 10 wk. The interceptors contributed to the IPM program efficacy and were much more effective than visual inspections in estimating bed bug numbers and determining the existence of bed bug infestations.

Call for Papers: Special Issue of Earth, Planets and Space (EPS) Cosmic Dust: Its Formation and Evolution

Call for Papers: Special Issue of Earth, Planets and Space (EPS) Cosmic Dust: Its Formation and Evolution

Stardust findings favor not only the planetary origin of comets but the underlying close-binary cosmogony of the Solar System as well

Abstract We analyze findings of the Stardust mission that brought to the Earth dust from the 81P/Wild 2 coma. Just as the data obtained in the Deep Impact mission to 9P/Tempel 1, they are at odds with the universally accepted condensation/sublimation comet paradigm. They fit rather well to the approach assuming ejection of nuclei of short-period comets from Moon-like bodies of the type of Galilean satellites in rare (six to seven events in 4.5 aeons) global explosions of their massive icy envelopes saturated by 2H 2 + O 2 , products of the electrolysis of ice. This approach offers an explanation, in particular, for the jet activity of comets, which is sustained by combustion of the 2H 2 + O 2 + organics mixture ignited and complemented by the solar radiation. Combustion accounts also for other observations, in particular, the presence in the dust of products of high-temperature (800–900 K) metamorphism. The presence of minerals forming at still higher temperatures (∼1400–2000 K), just as the undoubtedly planetary origin of some long-period comets arriving from the joint planeto-cometary cloud beyond Neptune, forces one, however, to invoke the close-binary cosmogony of the Solar System, which three decades ago predicted the existence of such a cloud (in the recent decade, this prediction has been substantiated by the discovery there of many dwarf planets). This cosmogony is based on the modern understanding of the processes involved in the formation of multiple stellar systems and of their gas-dynamic evolution. It considers the Jupiter–Sun system as the limiting case of a binary star and uses it as a basis for explanation of all the known observations and for prediction of the new ones to come. It provides a plausible explanation, in particular, for both the origin and capture by the Earth of the Moon as a high-temperature condensate and the formation of the Galilean satellites, which also contain inclusions of refractory minerals in the ices of their envelopes.

Physicochemical characteristics of ambient particles settling upon leaf surfaces of urban plants in Beijing

Particulate pollution is a serious health problem throughout the world, exacerbating a wide range of respiratory and vascular illnesses in urban areas. Urban plants play an important role in reducing particulate pollution. Physicochemical characteristics of ambient particles settling upon leaf surfaces of eleven roadside plants at four sites of Beijing were studies. Results showed that density of particles on the leaf surfaces greatly varied with plant species and traffic condition, Fraxinus chinensis, Sophora japonica, Ailanthus altissima, Syringa oblata and Prunus persica had larger densities of particles among the tall species. Due to resuspension of road dust, the densities of particles of Euonymus japonicus and Parthenocissus quinquefolia with low sampling height were 2—35 times to other taller tree species. For test plant species, micro-roughness of leaf surfaces and density of particles showed a close correlation. In general, the larger micro-roughness of leaf surfaces is, the larger density of particles is. Particles settling upon leaf surfaces were dominantly PM 10 (particulate matter less than 10 μm in aerodynamic diameter; 98.4%) and PM 2.5 (particulate matter less than 2.5 μm in aerodynamic diameter; 64.2%) which were closely relative to human health. Constant elements of particles were C, O, K, Ca, Si, Al, Mg, Na, Fe, S, Cl and minerals with higher content were SiO 2, CaCO 3, CaMg(CO 3) 2, NaCl and 2CaSO 4·H 2O, SiO 2. CaCO 3 and CaMg(CO 3) 2 mainly came from resuspension of road dust. 2CaSO 4·H 2O was produced by the reaction between CaCO 3 derived from earth dust or industrial emission and SO 2, H 2SO 4 or sulfate. NaCl was derived from sea salt.

Eolian dust and climate: relationships to sources, tropospheric chemistry, transport and deposition

The amount of atmospheric dust suspended in the atmosphere and subsequently deposited on land and in the oceans is largely controlled by processes related to climate; however, the dust's presence in the atmosphere also can affect climate and, as a result, feedbacks between dust and climate are possible. By scattering and absorbing incoming solar and outgoing infrared radiation, dust particles can alter the Earth's radiative balance. The net effect of the Earth's dust veil can be one of heating or cooling depending on a number of variables, especially the concentration, composition and physical properties of the dust; the albedo of the surface underlying the suspended dust; and the vertical distribution of dust in the atmosphere. Indirect feedbacks between dust and climate also are possible as a result of the dust's chemical reactivity and involvement in the biogeochemical cycles of other substances with links to climate. Studies of modern dust fluxes and their connections to climate are important, not only for developing methods for predicting the impacts of future climate change scenarios, but also for strengthening the underpinnings of paleoclimate reconstructions.

Chemical analysis of natural particulate impact residues on the long duration exposure facility

Abstract In situ collection of cosmic dust and space debris on the Low Earth Orbit has yielded a new perspective of the near Earth dust environment. The hypervelocity impact craters on the trailing side of the Long Duration Exposure Facility were converted into the projectile sizes and the physical and elemental comparison with interplanetary dust particles captured in the stratosphere was carried out. The size distribution agreed well while some chemical elements of LDEF samples suggested a fluctuation due to massive energy transfer during the hypervelocity impact in space. A possible selection process is discussed. Also, future opportunity of in situ detection of meteor showers is foreseen as long as new intact-capture materials are properly developed.

Up to Heaven's Gate, Down in Earth's Dust: The Politics of Judgment in Uncle Tom's Cabin

Up to Heaven's Gate, Down in Earth's Dust: The Politics of Judgment in Uncle Tom's Cabin