Major Indoor Research Articles

Combined exposure to formaldehyde and PM2.5: Hematopoietic toxicity and molecular mechanism in mice

PM2.5 and formaldehyde (FA) are major outdoor and indoor air pollutants in China, respectively, and both are known to be harmful to human health and to be carcinogenic. Of all the known chronic health effects, leukaemia is one of the most serious health risks associated with these two pollutants. To explore the influence and underlying mechanisms of exposure to formaldehyde and PM2.5 on hematopoietic toxicity, we systematically studied the toxicity induced in hematopoietic organs: bone marrow (BM); spleen; and myeloid progenitor cells (MPCs). Male Balb/c mice were exposed to: PM2.5 (20, 160 μg/kg·d) at a dose of 40 μL per mouse or formaldehyde (0.5, 3.0 mg/m3) for 8 h per day for 2 weeks or co-exposed to formaldehyde and PM2.5 (20 μg/kg·d PM2.5 + 0.5 mg/m3 FA, 20 μg/kg·d PM2.5 + 3 mg/m3 FA, 160 μg/kg·d PM2.5 + 0.5 mg/m3 FA, 160 μg/kg·d PM2.5 + 3 mg/m3 FA) for 2 weeks. Similar toxic effects were found in the formaldehyde-only and PM2.5-only groups, including significant decrease of blood cells and MPCs, along with decreased expression of hematopoietic growth factors. In addition, individual exposure of formaldehyde or PM2.5 increased oxidative stress, DNA damage and immune system disorder by destroying the balance of Th1/Th2, and Treg/Th17. DNA repair was markedly inhibited by deregulating the mammalian target of rapamycin (mTOR) pathway. Combined exposure to PM2.5 and formaldehyde led to more severe effects. Administration of Vitamin E (VE) was shown to attenuate these effects. In conclusion, our findings suggested that PM2.5 and formaldehyde may induce hematopoietic toxicity by reducing the expression of hematopoietic growth factors, increasing oxidative stress and DNA damage, activating the ‘immune imbalance’ pathway and suppressing the DNA-repair related mTOR pathway. The hematopoietic toxicity induced by combined exposure of PM2.5 and formaldehyde might provide further insights into the increased incidence of hematological diseases, including human myeloid leukaemia.

Transmission and exposure of kitchen particles: A case study in an apartment

Particles emitted from the kitchen have been proven as one of the major indoor particulate pollutants which could pose serious risk on human health. Thus, it is critical to study the migration of kitchen particles and the impact of kitchen particles on non-kitchen zones. Since Chinese domestic kitchens are equipped with exhaust hoods, the capture efficiency of an exhaust hood in real residence was first measured. The capture efficiency was about 48% with the air flow rate of 0.125 m3/s. Second, the relative occupant exposure was calculated to quantify migration characteristics of kitchen particles under different ventilation models. Results show that the meteorological environment had little effect on migration by infiltration but significant by natural ventilation. In the dwelling layout of this study, relative occupant exposures showed an upward trend in windward and a downward trend in leeward. When the wind direction was 225°, wind speed had the greatest impact on particle migration. Finally, the effect of the opening and closing situation of kitchen door on air quality was analysed. Results show that closing the kitchen door increased the exposure in the kitchen by 30–58%, while the exposure in the study dropped to 43% of the door open status.

Transport and trajectory of cough-induced bimodal aerosol in an air-conditioned space

Aerosol generated from a human cough can be a potential major indoor health risk due to the possible transmission of infectious respiratory diseases to surrounding individuals within the same room and even could spread out via air-ventilation/conditioning systems. This study aims to investigate the transport characteristics and trajectory of coughed aerosols under the influence of conditioned air ventilation as well as near-by human breathing zone using computational fluid dynamics (CFD). An experimental system consisting of air-conditioned space with multiple inlets and outlets, a cough simulator and a receiver was built to validate the CFD predictions. The comparison is in good agreement. The CFD model was established as a transient three-dimensional multiphase multicomponent Eulerian–Lagrangian model and numerically solved using commercial software ANSYS Fluent. Both gas and liquid phases were modelled as multicomponent mixtures. With this CFD model, the indoor transport and trajectory of coughed aerosols can be accounted for the distributions of portions inhaled by each manikin, deposited on surfaces of manikins and chamber walls, as well as recirculated back into the ventilation system. Results reveal that the aerosol source location and the ambient air movement can be crucial factors of aerosol trajectory in terms of direct and indirect influence.

Impact of indoor air pollution in nursery and primary schools on childhood asthma

Poor indoor air quality in scholar environments have been frequently reported, but its impact on respiratory health in schoolchildren has not been sufficiently explored. Thus, this study aimed to evaluate the associations between children's exposure to indoor air pollution (IAP) in nursery and primary schools and childhood asthma. Multivariate models (independent and multipollutant) quantified the associations of children's exposure with asthma-related health outcomes: reported active wheezing, reported and diagnosed asthma, and lung function (reduced FEV1/FVC and reduced FEV1). A microenvironmental modelling approach estimated individual inhaled exposure to major indoor air pollutants (CO2, CO, formaldehyde, NO2, O3, TVOC, PM2.5 and PM10) in nursery and primary schools from both urban and rural sites in northern Portugal. Questionnaires and medical tests (spirometry pre- and post-bronchodilator) were used to obtain information on health outcomes and to diagnose asthma following the newest international clinical guidelines. After testing children for aeroallergen sensitisation, multinomial models estimated the effect of exposure to particulate matter on asthma in sensitised individuals. The study population were 1530 children attending nursery and primary schools, respectively 648 pre-schoolers (3–5 years old) and 882 primary school children (6–10 years old). This study found no evidence of a significant association between IAP in nursery and primary schools and the prevalence of childhood asthma. However, reported active wheezing was associated with higher NO2, and reduced FEV1 was associated with higher O3 and PM2.5, despite NO2 and O3 in schools were always below the 200 μg m−3 threshold from WHO and National legislation, respectively. Moreover, sensitised children to common aeroallergens were more likely to have asthma during childhood when exposed to particulate matter in schools. These findings support the urgent need for mitigation measures to reduce IAP in schools, reducing its burden to children's health.

In vivo respiratory toxicology of cooking oil fumes: Evidence, mechanisms and prevention

BackgroundAs cooking is an essential part of people’s daily life, cooking oil fumes (COF) has been recognized as one of the major indoor air pollutant. Mounting epidemiological evidence has indicated that COF exposure is significantly associated with an increased risk of various health effects including lung cancer, but toxicological studies are very limited. ObjectivesWe conduct a systematic study to provide toxicological evidence of COF exposure on the lungs, to examine the underlying toxicological mechanism, and to suggest intervention measures to mitigate this toxicity. MethodsA total 96 female rats were randomly divided into control groups, COF exposure groups (0.2, 2, 20 mg/kg) and vitamin E protection groups, receiving appropriate treatment for 30 days. First we measured airway hyperresponsiveness (AHR) followed by a lung histological analysis to investigate the toxicological effects of COF. We next analyzed the biomarkers of oxidative stress, inflammation, and apoptosis to examine the underlying toxicological mechanism, and finally we investigated the protective effects of vitamin E against the toxicity of COF. ResultsAHR measurement indicated that the airway resistance increased with the COF dose and the lung histological assay showed narrowing of the airway lumen, which provided evidence of the toxicological effects of COF. The biomarkers of oxidative stress (ROS and MDA), pro-inflammation (TNF-α and IL-1β), and apoptosis (NF-κB and Caspase-3) were all significantly increased with COF dose. We observed that above toxicological effects and biomarker levels induced by COF were significantly ameliorated after administration of VE. ConclusionThe toxicity of cooking oil fumes on the lungs is clear from the evidence and mechanism, and can be ameliorated by vitamin E. We suggested that oxidative stress may be primarily responsible for the observed cooking oil fumes-induced toxicity.

INDOOR AIR QUALITY MONITORING WITH ARDUINO - BASED EMBEDDED SYSTEM FOR TERRARIUMS

Terrariums are tiny gardens with a range of pots that are physically impregnated, with a number of flowers within. Currently, the transition from indoor to succulent plants and plants that thrive on a low water level is a major contributor to green indoor spaces. Even at home or at work, and poor indoor air quality contributes greatly to health problems and a clean environment, a person spends maximum time indoors. In an adulterated indoor environment, disease may be short - term or long-term based on length of stay. This work focuses on the presentation of an indoor air quality control module and an overview of the temperature , humidity and air quality of different terrarium choices in the Indian context. A low - cost proposal is made for the study of air quality and smart house surveillance with Arduino uno for indoor air quality control. A detailed analysis of the different plants taking into account the benefits of the inner atmosphere can be studied. The proposed system is proposed to track the pollution, smoke, temperature , humidity and air quality index from anywhere.

On the capture of ultralow-level benzene in indoor environments: Experiments, modeling and molecular simulation

Benzene is one of the major indoor air pollutants, according to the World Health Organization (WHO), and understanding its adsorption and the difference between the adsorption behavior of benzene and water are essential in developing high-performance, water-resistant adsorbents. This paper presents a comprehensive study of benzene adsorption in carbon nano-porous materials by combining high-resolution measurement, modeling and molecular simulation. High-resolution isotherms and isosteric heats of benzene adsorption in two materials, microporous activated carbon fiber (ACF) and micro-mesoporous CMK-3 were provided. It is found that CMK-3 has higher specific adsorption capacity than ACF at very low pressures (<10−3 P/P0), making it a promising adsorbent for benzene capture in indoor environments. The Dubinin – Radushkevich model were used to fit the isotherms over the low-pressure regions. Furthermore, the experimental isotherm and the isosteric heat were analyzed with molecular simulation results, and the emphasis is placed on the behavior at ultralow pressures of benzene, typically found in indoor environments. Suggestion on the evaluation and management of adsorbents in terms of minimizing the impacts of ambient moisture were provided.

(Invited) Development of Pulse-Heated Diaphragm Type MEMS Gas Sensors for Indoor Air Quality Measurement

Introduction Amid growing concern about indoor air quality (IAQ), MOS type gas sensors for the detection of volatile organic compounds (VOC) are widely used in household appliances such as air purifiers for on-demand control of the appliances depending on VOC concentration in surrounding air. There are also potential demands for gas sensors to be used for mobile applications, with which people can monitor environmental conditions in dwelling or workplaces. However, detection accuracy, power consumption and cost of conventional MOS type gas sensors have not yet reached the level generally required for VOC concentration monitoring by mobile applications. To solve these issues, we have developed a new diaphragm type MEMS gas sensor, and studied their appropriate pulsed heating conditions. This optimized MEMS sensor chip was integrated with an ASIC with built-in temperature and humidity sensors in a SMD package, and its practical performance and mechanical durability were evaluated. Sensor structures Two types of MEMS structures were used for this study as shown in Fig.1. Air-bridge type MEMS structure [1] [2] which is being produced on a commercial basis has a square-shaped micro hot plate (MHP) with dimensions of 0.1 x 0.1 mm. Materials of the sensor electrodes and heater are Platinum, and the gas sensing material is Palladium doped Tin dioxide, which is turned into a paste using terpineol as a solvent. The gas sensing material was applied onto the MHP by micro dispenser, and then was calcined at 450°C for 3 hours in an electric furnace. The newly developed diaphragm type MEMS structure has a round shape MHP with 270mm diameter which can avoid stress concentration of SiN/SiO2 membrane. Thickness of each layer stacked on the MHP was also optimized to achieve uniform dispersion of internal stress. The same sensing material as above mentioned was applied onto the MHP of the diaphragm type MEMS by screen printing method so that the gas sensing layers are formed in one printing pass on a wafer that produces 74K chips of MHP. Method In order to determine the appropriate pulsed heating conditions and thickness of the sensing material, sensor resistances in air (Ra) and in various concentrations of gases (Rg) were measured by using the air-bridge type MEMS sensor. The sensing material was intermittently heated for 100 ms at several different temperature conditions in a range from 300 ∼ 450 °C, and at different heating intervals ranging from 1 ∼ 60 seconds. The thickness of gas sensing layer was varied in a range from 20 ∼ 50 μm. For the diaphragm type MEMS sensor, the sensing material was heated at 430 °C for 100 ms at 1 second intervals. Results and Conclusions Sensing characteristics of the air-bridge type MEMS sensor to toluene and ethanol were investigated at different working temperature as shown in Fig. 2. Response to toluene increased as the working temperature decreased within the range between 350 °C and 450 °C, suggesting the capability for detecting low concentration toluene below 1 ppm. On the other hand, response to ethanol within the same temperature range remained largely the same. Toluene and ethanol sensitivities both drastically dropped at 300 °C. There were significant differences in toluene response depending on the heating intervals as shown in Fig.3. Response to toluene became smaller as the heating interval was longer. This result implies that a reaction of the gas sensing material with gas was inhibited by water vapor which had adsorbed on the surface of the sensing element during the heater OFF period. As for the effect of sensing material thickness on sensitivity, ethanol sensitivity was relatively more affected by the thickness than toluene. The sensor with the thinnest sensing layer showed the highest ethanol response, especially at a short heating interval. Taking these results into consideration, driving conditions of the diaphragm type MEMS sensor were determined as described above. Its sensing characteristics to various gases were examined as shown in Fig. 4. This sensor showed a particularly large response to m-xylene and hydrogen sulfide which are both among the major indoor air pollutants, and very small response to hydrogen and methane, both of which would work as an interference gas in IAQ measurement if present in ambient air. It was confirmed in parallel that the diaphragm type MEMS sensor with the determined driving conditions has a sufficient mechanical durability under the heater ON/OFF cycle test equivalent to 10 years operation, and the drop test which is required for mobile applications. The diaphragm type MEMS sensor produced by high-efficiency screen printing method was expected to have a capability as a practical solution for mobile IAQ monitoring. In addition, user-friendliness of the sensor was much improved by integrating with ASIC in comparison with conventional type single sensor.

Differences in purifying and resistance tolerance ability of Scindapsus and Chlorophytum to formaldehyde pollution

Formaldehyde is a major indoor air pollutant, and its removal decreases the health risk of urban inhabitants. Scindapsus and Chlorophytum are indoor plants that have been reported to remove formaldehyde. However, their ability to absorb formaldehyde, their resistance, and their morphological changes in response to formaldehyde absorption have not been reported to date. In this study, both Scindapsus and Chlorophytum were used as test materials and their phenotype, microscopic change, enzyme activity, gene expression, and ability to absorb formaldehyde were investigated in response to formaldehyde stress. The results showed that the ability of Chlorophytum to absorb formaldehyde was stronger than that of Scindapsus; moreover, the expression level of the ADH2 gene in Chlorophytum was significantly higher than in Scindapsus. However, Chlorophytum suffered more severe damage of the leaves than Scindapsus. The superoxide dismutase, peroxidase, and catalase enzyme activities of Chlorophytum were lower than those of Scindapsus in response to formaldehyde absorption. This showed that compared with Scindapsus, Chlorophytum had a strong ability to absorb formaldehyde but a weaker ability to tolerate formaldehyde. Based on these results, to purify formaldehyde pollution from indoor air, it is recommended to use the Chlorophytum. However, regular replacement of these damaged Chlorophytum plants should be implemented to retain a beautiful indoor environment.

Long-Tailed Silverfish (Ctenolepisma longicaudata) Control; Bait Choice Based on Primary and Secondary Poisoning.

The long-tailed silverfish (Ctenolepisma longicaudata) has recently made its appearance and demonstrated a tremendous proliferation in Norway, where it is currently considered a major indoor nuisance pest in modern buildings. To reduce the risk of human pesticide exposure, several baits with indoxacarb, clothianidin, fipronil or imidacloprid as the active ingredient were investigated to provide knowledge regarding their potential for integrated pest management solutions. Primary and secondary poisoning, as well as the durability of baits, were experimentally evaluated in bioassays. Baits with indoxacarb, clothianidin and fipronil killed more than 90% of the experimental insects (primary poisoning) when presented in competition with food. Only indoxacarb produced high mortality when dead conspecifics were consumed (secondary poisoning) and resulted in more than 75% mortality. The efficacy of baits with indoxacarb against C. longicaudata was also found to be very long. Laboratory degraded baits were consumed and induced high levels of mortality for more than a month, and field degraded baits for more than 6 months. Adults and juveniles were equally affected in the experiments. Primary and secondary toxicity in combination with long durability and effects on both life stages tested suggest that the bait has high-level potential as a safe control strategy against the long-tailed silverfish if indoxacarb is used as the active ingredient.

Formaldehyde and Total VOC (TVOC) Commercial Low-Cost Monitoring Devices: From an Evaluation in Controlled Conditions to a Use Case Application in a Real Building

Formaldehyde and volatile organic compounds (VOCs) are major indoor pollutants with multiple origins. Standard methods exist to measure them that require analytical expertise and provide, at best, an average value of their concentrations. There is a need to monitor them continuously during periods of several days, weeks, or even months. Recently, portable devices have become available. Two categories of portable devices are considered in this research paper: connected objects for the general public (price &lt;500 €) and monitoring portable devices for professional users (price in the range &gt;500 to 5000 €). The ISO method (ISO 16000-29) describes the standard for VOC detector qualification. It is quite complex and is not well adapted for a first qualitative evaluation of these low-cost devices. In this paper, we present an experimental methodology used to evaluate commercial devices that monitor formaldehyde and/or total volatile organic compounds (TVOC) under controlled conditions (23 °C, 50–65% relative humidity (RH)). We conclude that none of the connected objects dedicated to the general public can provide reliable data in the conditions tested, not even for a qualitative evaluation. For formaldehyde monitoring, we obtained some promising results with a portable device dedicated to professional users. In this paper, we illustrate, with a real test case in an office building, how this device was used for a comparative analysis.

Low-temperature catalytic degradation of the odorous pollutant hexanal by γ-MnOOH: The effect of Mn vacancies

Hexanal is a typical indoor odorant from wood-based products, which induces discomfort and irritation to human beings. The removal of hexanal has rarely been investigated. In this study, we found that the amount of Mn vacancies in γ-MnOOH significantly affects its catalytic activity toward hexanal degradation and transformation into CO 2 . The as-synthesized Mn vacancy-rich γ-MnOOH exhibited high efficiency toward hexanal removal, achieving 100% degradation of 15 ppm hexanal at 85 °C and complete transformation into CO 2 at 160 o C under the gas hourly space velocity of 240 L/(g·h); its activity could be completely regenerated by in-situ heat treatment at 180 °C. Moreover, it was found that the degradation of hexanal occurred in a stepwise manner, i.e., losing one CH 2 unit per step. Electron spinning resonance studies detected strong indicative signals for the presence of the superoxide anion radical (•O 2 – ) on Mn-vacancy-rich γ-MnOOH, which may act as active oxygen species for the hexanal degradation. Understanding the role of Mn-vacancy and the mechanism of hexanal degradation by γ-MnOOH are essential for developing efficient oxide catalysts for volatile organic compounds besides hexanal. Mn-vacancy rich γ-MnOOH was synthesized via the hydrothermal reaction between MnO 4 − and ethylene glycol with the addition of H 2 SO 4 , which could efficiently degrade a major indoor odorant, hexanal, at a low temperature.

Investigation of Indoor Air Quality in six office buildings in Chengdu, China based on continuous monitoring data

Indoor air pollution is of a growing concern in China. The nation’s growing urban work force spends prolonged periods in office, thus office indoor air quality (IAQ) can be a key determinant of worker’s wellbeing, yet, IAQ literature on China’s office space remains scarce. To address such knowledge gap, this study conducted continuous monitoring in six office towers in Chengdu, China to investigate two major indoor pollutants: PM2.5 and CO2. The participating office buildings were Grade-A certified and fully occupied. Indoor concentration for PM2.5 and CO2 ranged between 1-459 μg/m3 and 375-1102 ppm respectively, with considerable intra-building and inter-building variability. Time-series analysis suggests diurnal and weekly pattern for indoor CO2, and temporal association between indoor and ambient PM2.5. Filtration and ventilation efficiencies varied across buildings, and these buildings experienced various degrees of penetration by outdoor PM2.5 and indoor accumulation of CO2 on a daily basis. On days with ambient pollution, indoor pollution persisted. Multivariate model predicts an average of 0.6 μg/m3 increase in indoor PM2.5 for every 1 μg/m3 increase in ambient PM2.5. To our knowledge, this is the first systematic study of office buildings in China with findings potentially inform future IAQ management strategies.

A field study of indoor air quality and occupant perception in experimental laboratories and workshops

Purpose Maintaining good indoor air quality (IAQ) in the built environment is essential to assure health, safety and productivity of occupants. The purpose of this paper is to report on the preliminary IAQ assessment of selected air-conditioned laboratories and naturally ventilated workshops in a tropical education institution. Design/methodology/approach The concentration levels of five major indoor air pollutants (IAPs) – carbon dioxide, carbon monoxide, respirable particulates, formaldehyde (HCHO) and total volatile organic compounds (TVOC) in each sampling area were measured using calibrated air sampling sensors and the tracer-gas analysis was used to determine the ventilation effectiveness. A questionnaire survey was carried out concurrently to study the prevalence of sick building syndrome (SBS) among users of laboratories and workshops and the data collected were statistically analysed using χ2 test. Findings The air pollutant levels were found to be below the threshold limit values set in the local code of practice on IAQ, except for two of the air-conditioned laboratories. This is possibly due to insufficient ventilation, smaller floor area per occupant ratio, long-term exposure to chemical substances, and improper disposal of the used chemical substances. The total particulate levels were higher in naturally ventilated workshops because such spaces were assigned for mechanical works which involved grinding, welding and fabrication. Besides, it was identified that most of the air contaminant levels were not normally distributed (p&lt;0.05) within the sampling areas and SBS like dry eyes, watery eyes, tiredness and dry throat were reported in both laboratories and workshops. The outcomes of this work suggest that an increase of ventilation rate was necessary to reduce the concentration of the IAPs in air-conditioned laboratories and improved housekeeping would help mitigate the prevalence of SBS symptoms. Research limitations/implications This research was carried out in selected laboratories and workshops in a Malaysian educational institution and only five major IAPs stipulated in the Department of Occupational Safety and Health (DOSH) code of practice were measured. Practical implications The results of this study will enable facility engineers and managers to understand the IAPs concentration levels and potential SBS problems in academic laboratories and workshops. The recommended strategies can be considered to improve IAQ conditions in such spaces. Originality/value Most of the previously conducted IAQ studies focused only on commonly occupied building spaces such as offices, classrooms and houses. Information of the quality of air and SBS conditions in experimental facilities in developing nations that is available is currently very limited. This case study provides detailed information on IAQ in laboratories and workshops in Malaysia with focuses on the concentration levels of particular harmful gases, the prevalence of SBS among users of these facilities and the appropriate mitigation strategies. The results presented are of value to both academic and industry communities.

Optimising an archer’s foot position to obtain a competitive advantage

The World Archery shooting rules provide some latitude in relation to an archer’s position on the shooting line. This means that the archer could stand at different distances from the target, while still meeting competition regulations. One would think that standing closer to the target should be an advantage; however, most archers do not take this approach. This article considers the score increase that may be attributable to standing in the optimum position, which can lead to a potential higher ranking place at major international indoor and outdoor archery competitions.

Heavy Metals Contents and Health Risk Assessment of Classroom Corner Dusts in Selected Public Primary Schools in Rivers State, Nigeria

Heavy metals are shown to be a major indoor dusts pollutant. The health risk assessment of Heavy metal contents of dusts collected from classroom corners of some randomly selected public primary schools in Rivers state was carried out. Dust samples from Classroom corners of three (3) Public primary Schools in Obio/Akpor, Eleme, and Ikwerre Local Government Areas (LGAs) was collected and analyzed for Lead (Pb), Cadmium (Cd), Chromium (Cr), and Arsernic (As) using Atomic Absorption Spectrophotometer (AAS, GF, Flame HVG). The heavy metal concentrations obtained from the analysis revealed that mean maximum level for Pb and Cd were obtained from E at 25.39±0.09 and 3.52±0.23 mg kg-1 respectively, while that of Cr and As were obtained from H at 45.24±0.02 and 1.53±0.06 mg kg-1. The minimum levels were observed at E. The Average daily intake Dose (ADDingestion, dermal and inhalation) and corresponding Target Hazard Quotients obtained revealed oral ingestion as major exposure pathway, though with no evidence for non carcinogenic risk/Hazard index (HI), but with children population being more exposed to Life cancer Risks (TLCR) except at F. It is however recommended that same risk assessment be made on agricultural products harvested from Primary School Farms and Borehole water within these regions.

Changes in the Peripheral Chemosensory System Drive Adaptive Shifts in Food Preferences in Insects

A key challenge in understanding the evolution of animal behaviors is to identify cellular and molecular mechanisms that underlie the evolution of adaptive traits and behaviors in polymorphic populations under local selection pressures. Despite recent advances in fish, mice, and insects, there are still only a few compelling examples of major genes and cellular mechanisms associated with complex behavioral changes. Shifts in food or host preferences in insects, accompanied by changes in the peripheral chemosensory system, offer some of the best examples of adaptive behavioral evolution. A remarkable example is the German cockroach, Blattella germanica, a major indoor pest with a highly diverse omnivorous diet. Strong and persistent selection pressure with toxic-baits has induced rapid evolution of behavioral resistance in multiple cockroach populations. While typical cockroaches detect and accept the sugar glucose as a feeding-stimulant, behaviorally resistant cockroaches avoid eating glucose-containing toxic baits by sensing glucose as a deterrent. We review the peripheral gustatory neural mechanisms of glucose-aversion and discuss how the rapid emergence of taste polymorphisms can impede pest control efforts and affect foraging and mate-choice in adapted cockroach populations.

Heat Shock Protein 60: Identification of an Undetected Allergen from Dermatophagoides farinae.

BackgroundRecently, the incidence of allergic diseases has been on the rise; Dust mite is the major indoor allergen which needs a special consideration.ObjectivesThis study was carried out to identify and investigate the molecular properties of a new allergen named Hsp60 and to afford a foundation for future research of the allergic diseases caused by Dermatophagoides farinae.Materials and MethodsUsing polymerase chain reaction (PCR) with degenerate primer, the cDNA of Dermatophagoides farinae Hsp60 was amplified and sequenced. Next, the cDNA fragment was cloned into the prokaryotic expression vector pET-32a for the expression of the Hsp60. Then, it was further characterized by Elisa and Western Blot analysis.ResultsThe partial cDNA sequence of the Dermatophagoides farinae Hsp60 was determined, and the recombinant Hsp60 was successfully expressed in Escherichia coli BL21. ELISA and Western blot analysis showed that the recombinant protein could be specifically recognized by SIgE from sera of the Dermatophagoides farina-allergic patients.ConclusionsOur group has, for the first time, demonstrated the fact that there is an Hsp60 family of Dermatophagoides farinae and analyzed the allergenicity of the Hsp60 with immunological method. These results provide a foundation for further allergological research of the Dermatophagoides farinae Hsp60.

DNA Methylome Analysis of Saturated Aliphatic Aldehydes in Pulmonary Toxicity

Recent studies have investigated the epigenetic effects of environmental exposure to chemicals on human health. The associations of DNA methylation, environmental exposure and human diseases have been widely demonstrated. However, the use of gene methylation patterns as a predictive biomarker for exposure to environmental toxicants is relatively poorly understood. Here, we focused on low-molecular-weight saturated aliphatic aldehydes (LSAAs), which are important environmental risk factors in humans as major indoor air pollutants. Based on DNA methylation profiling in gene promoter regions, we analysed DNA methylation profiles following exposure of A549 cells to seven LSAAs (propanal, butanal, pentanal, hexanal, heptanal, octanal, and nonanal) to identify LSAA-characterized methylated sites and target genes, as well as to investigate whether exposure to LSAAs contributes to inducing of pulmonary toxicity. Additionally, by integrating DNA methylation and mRNA expression profile analyses, we identified core anti-correlated target genes. Gene ontology analysis of these target genes revealed several key biological processes. These findings suggest that alterations in DNA methylation by exposure to LSAAs provide novel epigenetic biomarkers for risk assessments. This DNA methylation-mRNA approach also reveals potential new mechanistic insights into the epigenetic actions of pulmonary toxicity.

Effect of K+ ions on efficient room-temperature degradation of formaldehyde over MnO2 catalysts

δ-MnO2 was prepared via a facile in-situ redox reaction and used for catalytic oxidation of HCHO, a major indoor air pollutant. The washing treatment during catalyst preparation could impose great effect on content of K+ and catalytic activity. δ-MnO2 catalyst without washing treatment contains the highest content of K+ ion and exhibits the best catalytic activity among various δ-MnO2 samples. The HCHO removal efficiency keeps at 100% for first 600 min. The δ-MnO2 samples were characterized by advanced technologies including XRD, Raman, XPS, TPR, TPD and in-situ DRIFTS. The XPS results indicates that K+ ions increases the AOS value of Mn and the ratio of surface-adsorbed oxygen over δ-MnO2. The content of K+ ions improves the amount and redox ability of surface mobile oxygen species, enhancing catalytic oxidation of HCHO.