Effect Of High Relative Humidity Research Articles

Temperature modification of air pollutants and their synergistic effects on respiratory diseases in a semi-arid city in Northwest China.

Air pollutants and temperature are significant threats to public health, and the complex linkages between the environmental factors and their interactions harm respiratory diseases. This study is aimed to analyze the impact of air pollutants and meteorological factors on respiratory diseases and their synergistic effects in Dingxi, a city in northwestern China, from 2018 to 2020 using a generalized additive model (GAM). Relative risk (RR) was employed to quantitatively evaluate the temperature modification on the short-term effects of PM2.5 and O3 and the synergistic effects of air pollutants (PM2.5 and O3) and meteorological elements (temperature and relative humidity) on respiratory diseases. The results indicated that the RRs per inter-quatile range (IQR) rise in PM2.5 and O3 concentrations were (1.066, 95% CI: 1.009-1.127, lag2) and (1.037, 95% CI: 0.975-1.102, lag4) for respiratory diseases, respectively. Temperature stratification suggests that the influence of PM2.5 on respiratory diseases was significantly enhanced at low and moderate temperatures, and the risk of respiratory diseases caused by O3 was significantly increased at high temperatures. The synergy analysis demonstrated significant a synergistic effect of PM2.5 with low temperature and high relative humidity and an antagonistic effect of high relative humidity and O3 on respiratory diseases. The findings would provide a scientific basis for the impact of pollutants on respiratory diseases in Northwest China.

Dynamic Marine Atmospheric Corrosion Behavior of AZ91 Mg Alloy Sailing from Yellow Sea to Western Pacific Ocean.

In this work, the dynamic marine atmospheric corrosion behavior of AZ91 Mg alloy sailing from Yellow Sea to Western Pacific Ocean was studied. The corrosion rates were measured using the weight loss method. The microstructure, phase, and chemical composition of corroded samples were investigated by SEM, EDS, XRD, and XPS. The results show that the evolution of corrosion rates of AZ91 Mg alloy was divided into three stages: rapidly increasing during the first 3 months, then remaining stable for the next three months, and finally decreasing after 6 months. The annual corrosion rate of Mg alloy reached 32.50 μm/y after exposure for 12 months in a dynamic marine atmospheric environment, which was several times higher than that of the static field exposure tests. AZ91 magnesium alloy was mainly subjected to localized corrosion with more destructiveness to Mg parts, which is mainly due to the synergistic effect of high relative humidity, the high deposition rate of chloride ion, sulfur dioxide acidic gas produced by fuel combustion, and rapid temperature changes caused by the alternating changes in longitude and latitude during navigation. As the exposure time increased, the corrosion pits gradually increased and deepened. The maximum depth of the corrosion pit was 197 μm after 12 months of exposure, which is almost 6 times the average corrosion depth. This study provides scientific data support for the application of magnesium alloys in shipborne aircraft and electronic equipment. The results could provide guidance for the design of new magnesium alloys and development of anti-corrosion technologies.

Stratégies de gestion de la chaleur et performances sportives de haut niveau : éclairage psychophysiologique et recommandations appliquées

Objectives: This article sheds light on the different heat stress management strategies, common or innovative, in order to analyze those that would be the most suitable and effective for athletes who have to compete in humid and/or hot environments.News: The Paris summer Olympics Games in 2024 will take place from July 26th to September 8th with a high risk for athletes to practice their sport at high temperatures, thereby imposing physiological (cardiovascular, ventilatory, thermoregulatory, etc.) and psychological (early mental fatigue, decreased motivation, discomfort, etc.) which can have a major negative impact on their performance.Prospects and projects: To perform in a hot environment, it is now recommended to use strategies, in particular active acclimatization which promotes physiological but also psychological adaptations. Similarly, fluid management and cooling techniques have potentially beneficial effects on physiological factors but their psychological consequences are still poorly understood and need to be investigated. Finally, mental strategies (goal setting, mental imagery, positive self-talk, music, etc.) or cognitive training in the heat can limit poor performance in this condition. The effects of combining physical and mental techniques, as well as innovative strategies such as cold suggestion, are also being investigated.Conclusion: For each strategies presented, the scientific work has enabled the development of practical recommendations for athletes, coaches and mental trainers in order to allow them to physiologically and psychologically anticipate the effects of high relative humidity and/or high temperature.

Gut microbiota mediated the effects of high relative humidity on lupus in female MRL/lpr mice

IntroductionThe relationship between humidity and systemic lupus erythematosus (SLE) has yielded inconsistent results in prior research, while the effects of humidity on lupus in animal experiments and its underlying mechanism remain inadequately explored.MethodsThe present study aimed to investigate the impact of high humidity (80 ± 5%) on lupus using female and male MRL/lpr mice, with a particular focus on elucidating the role of gut microbiota in this process. To this end, fecal microbiota transplantation (FMT) was employed to transfer the gut microbiota of MRL/lpr mice under high humidity to blank MRL/lpr mice under normal humidity (50 ± 5%), allowing for an assessment of the effect of FMT on lupus.ResultsThe study revealed that high humidity exacerbated lupus indices (serum anti-dsDNA, ANA, IL-6, and IFN- g, and renal pathology) in female MRL/lpr mice but had no significant effect on male MRL/lpr mice. The aggravation of lupus caused by high humidity may be attributed to the increased abundances of the Rikenella, Romboutsia, Turicibacter, and Escherichia-Shigella genera in female MRL/lpr mice. Furthermore, FMT also exacerbated lupus in female MRL/lpr mice but not in male MRL/lpr mice.ConclusionIn summary, this study has demonstrated that high humidity exacerbated lupus by modulating gut microbiota in female MRL/lpr mice. The findings underscore the importance of considering environmental factors and gut microbiota in the development and progression of lupus, particularly among female patients.

Evaluation of a low-cost dryer for a low-cost optical particle counter

Abstract. The use of low-cost sensors for air quality measurements has become very popular in the last few decades. Due to the detrimental effects of particulate matter (PM) on human health, PM sensors like photometers and optical particle counters (OPCs) are widespread and have been widely investigated. The negative effects of high relative humidity (RH) and fog events in the mass concentration readings of these types of sensors are well documented. In the literature, different solutions to these problems – like correction models based on the Köhler theory or machine learning algorithms – have been applied. In this work, an air pre-conditioning method based on a low-cost thermal dryer for a low-cost OPC is presented. This study was done in two parts. The first part of the study was conducted in the laboratory to test the low-cost dryer under two different scenarios. In one scenario, the drying efficiency of the low-cost dryer was investigated in the presence of fog. In the second scenario, experiments with hygroscopic aerosols were done to determine to which extent the low-cost dryer reverts the growth of hygroscopic particles. In the second part of the study, the PM10 and PM2.5 mass concentrations of an OPC with dryer were compared with the gravimetric measurements and a continuous federal equivalent method (FEM) instrument in the field. The feasibility of using univariate linear regression (ULR) to correct the PM data of an OPC with dryer during field measurement was also evaluated. Finally, comparison measurements between an OPC with dryer, an OPC without dryer, and a FEM instrument during a real fog event are also presented. The laboratory results show that the sensor with the low-cost dryer at its inlet measured an average of 64 % and 59 % less PM2.5 concentration compared with a sensor without the low-cost dryer during the experiments with fog and with hygroscopic particles, respectively. The outcomes of the PM2.5 concentrations of the low-cost sensor with dryer in laboratory conditions reveal, however, an excess of heating compared with the FEM instrument. This excess of heating is also demonstrated in a more in-depth study on the temperature profile inside the dryer. The correction of the PM10 concentrations of the sensor with dryer during field measurements by using ULR showed a reduction of the maximum absolute error (MAE) from 4.3 µg m−3 (raw data) to 2.4 µg m−3 (after correction). The results for PM2.5 make evident an increase in the MAE after correction: from 1.9 µg m−3 in the raw data to 3.2 µg m−3. In light of these results, a low-cost thermal dryer could be a cost-effective add-on that could revert the effect of the hygroscopic growth and the fog in the PM readings. However, special care is needed when designing a low-cost dryer for a PM sensor to produce FEM similar PM readings, as high temperatures may irreversibly change the sampled air by evaporating the most volatile particulate species and thus deliver underestimated PM readings. New versions of a low-cost dryer aiming at FEM measurements should focus on maintaining the RH at the sensor inlet at 50 % and avoid reaching temperatures higher than 40 ∘C in the drying system. Finally, we believe that low-cost dryers have a very promising future for the application of sensors in citizen science, sensor networks for supplemental monitoring, and epidemiological studies.

Non-Stationarity of Aerosol Extinction Coefficient per Unit of Mass in Autumn and Winter in Chengdu, China

Based on hourly observation data from the aethalometer and GRIMM180 environment particle monitor as well as the simultaneous data of visibility (V), relative humidity (RH) and nitrogen dioxide (NO2) from October to December in 2017 in Chengdu, the corresponding time series of aerosol extinction coefficient per unit of mass is retrieved. The generalized additive models (GAMs) are adopted to analyze the non-stationarity of the time series of aerosol extinction coefficient per unit of mass and to explore the responses of the aerosol extinction coefficient per unit of mass to the aerosol component structure factors (ρBC/ρPM10, ρPM1/ρPM2.5, ρPM1~2.5/ρPM2.5 and ρPM2.5/ρPM10; ρ represents particle mass concentration) and RH. The results show that through the comparative analysis of stationary and non-stationary models, the time series of aerosol extinction coefficient per unit of mass in autumn and winter in Chengdu is non-stationary. In addition, the RH and aerosol component structure factors are all significant nonlinear covariates that affect the non-stationarity of the aerosol extinction coefficient per unit of mass. According to the influence of covariates, the sequence is as follows: RH > ρBC/ρPM10 > ρPM2.5/ρPM10 > ρPM1/ρPM2.5. At PM2.5 pollution concentration (ρPM2.5 > 75 μg m−3), according to the influence of covariates, the sequence is as follows: RH > ρPM1~2.5/ρPM2.5 > ρBC/ρPM10 > ρPM2.5/ρPM10. Moreover, the interaction between RH and aerosol component structure factors significantly affects the aerosol extinction coefficient per unit of mass. The condition of high RH, high ρPM2.5/ρPM10, high ρPM1/ρPM2.5 and low ρBC/ρPM10 has a synergistic amplification effect on the increase of the aerosol extinction coefficient per unit of mass. At PM2.5 pollution concentration, the synergistic effect of high RH, high ρPM2.5/ρPM10, high ρPM1~2.5/ρPM2.5 and low ρBC/ρPM10 is beneficial to the increase of the aerosol extinction coefficient per unit of mass.

Combined effects of high relative humidity and ultraviolet irradiation: Enhancing the production of gaseous NO2 from the photolysis of NH4NO3

Free radicals and nitrogen-containing species produced by nitrate photolysis can affect various atmospheric chemical processes, and thereby the photochemical behavior of atmospheric nitrate aerosols has been attracting much attention. However, the photolysis mechanism of NH4NO3 and its products under different atmospheric conditions remain unclear. In this study, the effects of relative humidity (RH), pH, NH3, ultraviolet (UV) light intensity and halogen ions (Cl−, Br− and I−) on the photolysis of particulate NH4NO3 have been investigated through a flow tube reactor. The results show that RH can significantly enhance the production of gaseous NO2 from the photolysis of NH4NO3 when RH is higher than its deliquescence RH, but almost no NO2 is generated under dry conditions. Under high RH and UV light, the main product of NH4NO3 photolysis is NO2, rather than NO and HONO, and another main species HNO3 which mainly comes from the hydrolysis of product NO2 in the gas path was detected. Almost no NO2 and HNO3 are produced under high RH without UV light or low RH with UV light, showing the combined effect of high RH and UV irradiation on the photolysis of NH4NO3. In addition, under high RH, the lower the pH and the stronger the light intensity, the higher the NO2 production. Furthermore, surprising yields of NO and HONO are detected in the presence of halogen ions, especially in the presence of I−, indicating the important role of halogen ion in the nitrate photolysis. These results provide new insights into the photolysis of atmospheric nitrate aerosols, and may contribute to elucidating the formation and migration of atmospheric nitrate aerosols and the potential mechanisms of the occurrence and evolution of atmospheric pollution and ozone pollution.

THE EFFECTS OF HIGH RELATIVE HUMIDITY AND TEMPERATURE ON THE BORON POTASSIUM NITRATE (BPN) PYROTECHNIC COMPOSITION

THE EFFECTS OF HIGH RELATIVE HUMIDITY AND TEMPERATURE ON THE BORON POTASSIUM NITRATE (BPN) PYROTECHNIC COMPOSITION

The effect of high relative humidity on a network of water-sensitive particles (couscous) as revealed by in situ X-ray tomography.

Water significantly influences the mechanical behaviour of all granular materials but none as much as hygroscopic amorphous particles. With sufficiently high water content, particles can swell, agglomerate and their mechanical properties can be reduced, having direct effects on the macroscopic response of the material. In the food and pharmaceutical industry this can cause loss of product functionality. Despite their relevance, very little is known about the microscopic processes that induce these phenomena. Previous studies focused on single particle behaviour, the strength of agglomerated particles and the material flowability, leaving unexplored the link connecting the particle behaviour and the bulk response. This experimental study aims to investigate this aspect with quantitative measurements at both particle and macroscopic scales. A sample of fine couscous is exposed to a high relative humidity (RH) air flow, while being subjected to oedometric conditions, in order to reproduce the storage-silo conditions. In the meantime, X-ray tomographies are acquired continuously and the resulting images are analysed. The designed spatial resolution allows each particle of the sample to be identified and tracked, allowing volumetric evolution to be compared to the properties of the whole sample. The analysis reveals a dilation-compaction macroscopic behaviour, a result of the competition between the particle swelling and the higher deformability as the water content increases. The number, orientations and inter-particle contacts are computed. Their area is related to the applied boundary conditions, and is found to be consistent with the particle swelling and dependent on the applied stress direction.

Mathematical modeling of a modular convection-enhanced evaporation system

This study presents mathematical modeling of a novel convection-enhanced evaporation (CEE) system. The proposed system represents a modular brine management option for decentralized desalination plants and small-scale industries. Liquid is pumped over horizontally packed evaporation surfaces and forced convection is induced by means of a fan. The developed model of heat and mass transfer in the CEE system is solved using the finite difference method to predict the evaporation rate and the spatial distribution of humidity and temperature, based on operating condition (ambient temperature and relative humidity, air flow speed, and the spacing between the evaporation surfaces) and liquid inlet condition (temperature, flow rate and salinity). Comparison between model-predicted evaporation rates and experimental results show good agreement; for 11 out of 16 operating conditions error was within 10%, for 4 conditions error was within 20%, and for 1 condition error was within 35%. The effect of various operating conditions on the evaporation performance is also investigated. An increase in evaporation of up to 13 times is achieved by active control of liquid inlet temperature and air flow speed. Preheating the liquid was found to be a good strategy to overcome the negative effect of high relative humidity.

Severe acute respiratory syndrome coronavirus-2 medical solid waste treatment: A need for efficient and effective strategies in low-resourced settings.

Understanding infections related to handling healthcare waste products is of critical importance and the application of simple and low-cost strategies remain a priority in low-income and middle-income countries to protect healthcare workers. We examined the potential effect of relative humidity (RH), air temperature and ultraviolet irradiation (UI) to establish an efficient and effective way to facilitate disposal of medical waste. Literature is emerging on the effect of high RH and high temperature, which would increase airborne mass deposition and decrease the viability of viruses in both airborne particles and on surfaces. On the other hand, severe acute respiratory syndrome coronavirus-2 has been proven to be susceptible to UI when suspended in air like other coronaviruses. An innovative approach utilizing environmental conditions might represent an effective and efficient way to ensure better and sustainable protection of the healthcare workers in low-resourced settings.

Effects of high relative humidity and dry purging on VOCs obtained during breath sampling on common sorbent tubes

Offline breath analysis by thermal desorption gas chromatography mass spectrometry (TD-GC-MS) requires the use of sorbent traps to concentrate and store volatile compounds. The selection of which sorbent to use and best practices for managing high relative humidity are important considerations to allow for reproducible, untargeted, biomarker discovery in water saturated breath samples. This work aims to assess three commonly used sorbent materials for their use in breath volatile sampling and determine how the high relative humidity inherent in such samples effects the capture of volatile compounds of interest. TenaxGR, TenaxTA/Carbograph1TD and TenaxTA/Carbograph5TD tubes were selected as they are the most commonly used sorbents in the breath sampling literature. The recovery of 29 compounds in a standard mix loaded using high humidity gas was tested for each sorbent and compared to loading in dry gas. Water retention and dry purge rates were determined for each sorbent for 500 ml and 1000 ml breath collections. Finally, breath samples were collected simultaneously on to each sorbent type using the ReCIVA and analysed by TD-GC-MS. All three sorbents exhibited acceptable reproducibility when loaded with the standard mix in dry gas (RSD < 10%). Loading the standard mix in humid gas led to reduced recovery of compounds based on their chemical properties. Dry purging performance for each sorbent material was assessed and was shown to be 1.14, 1.13 and 0.89 mg H2O min−1 for TenaxGR, TenaxTA/Carbograph1TD and TenaxTA/Carbograph5TD respectively when flushed with 50 ml min−1 of N2. A comparison of breath profiles on different sorbents showed differences in background artefacts (sulfur dioxide, cyclopenten-1-one and 3-nonene) and endogenous breath compounds (2-methyl-furan and furfural). This work demonstrates that high relative humidity during sampling reduces the ability of sorbent tubes to capture volatile compounds and could impact method detection limits during breath sampling. Sufficient water to impair accurate analysis was retained on all tubes. Minimal differences were observed between sorbent materials when used to sample breath, however, suggestions are provided for sorbent selection for future studies.

Exposure to both formaldehyde and high relative humidity exacerbates allergic asthma by activating the TRPV4-p38 MAPK pathway in Balb/c mice

Some studies have indicated that formaldehyde, a ubiquitous environmental pollutant, can induce or aggravate allergic asthma. Epidemiological studies have also shown that the relative humidity indoors may be an independent and a key factor associated with the aggravation of allergic asthma. However, the synergy of humidity and formaldehyde on allergic asthma and the mechanism underlying this effect remain largely unknown. In this study, we aim to determine the effect of high relative humidity and/or formaldehyde exposure on allergic asthma and explore the underlying mechanisms. Male Balb/c mice were modeled with ovalbumin (OVA) and exposure to 0.5 mg/m3 formaldehyde and/or different relative humidity (60%/75%/90%). Histopathological changes, pulmonary function, Th1/Th2 balance, the status of mucus hypersecretion and the levels of inflammatory factors were detected to assess the exacerbation of allergic asthma. The levels of the transient receptor potential vanilloid 4 (TRPV4), calcium ion and the activation of p38 mitogen-activated protein kinases (p38 MAPK) were detected to explore the underlying mechanisms. The results showed that exposure to high relative humidity or to 0.5 mg/m3 formaldehyde alone had a slight, but not significant, affect on allergic asthma. However, the pathological response and airway hyperresponsiveness (AHR) were greatly aggravated by simultaneous exposure to 0.5 mg/m3 formaldehyde and 90% relative humidity. Blocking TRPV4or p38 MAPK using HC-067047 and SB203580 respectively, effectively alleviated the exacerbation of allergic asthma induced by this simultaneous exposure to formaldehyde and high relative humidity. The results show that when formaldehyde and high relative humidity are present this can enhance the activation of the TRPV4 ion channel in the lung leading to the aggravation of the p38 MAPK activation, resulting in the exacerbation of inflammation and hypersecretion of mucus in the airways.

A Plan to Document and Treatment an Archaeological Pottery Amphora from Early Dynastic - Helwan Cemetery

This research is concerned with putting a plan for documenting and treating an Archaeological pottery Amphorae, dating back to Early Dynastic. It was discovered in Helwan Cemetery, which is considered one of the most important Archaeological sites in Egypt, and has not yet revealed all its secrets. The pottery Amphorae was exposed to physical and chemical damage during burial and after excavation, from interactions with various damage factors. The damage extent after excavation has varied between the effect of the burial residues inside and outside the Amphorae, the cracks in the thickness of the body showing, clearly, in addition to the effect of high relative humidity with high temperature degrees on the crystallization of salts on the internal and external surface and between the crystals of the body which led to crusting and flaking off the surface. The components of the damaged pottery Amphorae will be identified through the use of different methods of documentation such as AutoCAD and other methods, and then the appropriate examination and analysis methods to identify the damage products, and then choice the treatment plan, using the Digital Optical Microscope, the Scanning Electron Microscope with the energy dispersion unit SEM-EDX, X-Ray Diffraction (XRD) to identify the crystallized mineral compounds to the body or deteriorate products, as well as differential thermal analysis (DTA) to determine the approximate firing degree, because they have an important role in determining the steps and the materials of treatment. It is recommended through this study that the treatment plan is suitable for the conditions in which the Amphorae will be present, whether it will be in storage or exhibition environment.

Risk effects of high and low relative humidity on allergic rhinitis: Time series study

BackgroundThe relationship between environmental factors and allergic rhinitis (AR) has become a focal point recently. However, few studies have investigated the adverse effects of both high relative humidity (RH) and low relative humidity. Moreover, the laged effect and disease burden of RH on AR were also neglected. ObjectivesTo explore the association of both high and low RH on daily AR hospital outpatients, and to quantify the corresponding disease burden attributable to RH. MethodsIn our study, we define 95th as high RH and 5th as low RH. A distributed lag non-linear model (DLNM) combined with a Poisson generalized linear regression model were applied to analyze the relationship between RH and hospital outpatients for AR. All patients were retrieved from Anhui Provincial Children's Hospital (n = 37,221) from January 2015 to December 2016. Daily meteorological and air pollutant data were collected by Hefei Meteorological Bureau and Environmental Protection Agency. Subgroup analyses were conducted by gender and occupational groups. ResultsAcute adverse effects of high and low RH on AR were explored respectively, with an increase of daily AR outpatients when encountered high and low RH. The low RH presented a risk effect at current day and lasted up to the eighth day. However, high RH began to appear a risk effect on the fourth day. Notably, the fraction of hospital outpatients attributable to low RH was 5.22% (95% CI: 1.92%, 8.33%) and high RH was 4.07% (95% CI: 1.13%, 7.30%) in the backward perspective. Additionally, male and students apparent to be more sensitive to the effects of low RH. ConclusionThis study suggests that both high and low RH are potential trigger for AR hospital outpatients in Hefei, China. Our studies might offer valuable messages to health practitioners and useful direction to decisions-makers respectively.

Durability of structural adhesive joints for facade applications exposed to the extended cataplasm test

ABSTRACTThe effects of exposure to humid conditions in the extended cataplasm ageing test, based on ISO 9142, Procedure E2 on the mechanical properties of adhesively bonded joints, were investigated as a part of a comprehensive study on the ageing of an acrylate adhesive and a Silane-terminated polymer (STP) adhesive. The adhesives were applied in aluminium and Zn-electroplated steel substrates with various surface treatments (a smooth surface, a roughened surface, and anodized and blank aluminium) to observe the effect of ageing on joints with various substrates. The predominant effect of high relative humidity in the cataplasm test was compared with the results of immersion in water according to ETAG 002. It is shown that both ageing methods had a significant degrading effect on bond strength, on stiffness, and on the failure mode. However, water immersion had a more serious effect on the acrylate adhesive, especially in anodized aluminium joints, and the cataplasm test caused slightly greater worsening of the adhesive properties of STP.

Effects of relative humidity on childhood hand, foot, and mouth disease reinfection in Hefei, China

BackgroundIn recent years, hand, foot, and mouth disease (HFMD) has become a major public health issue in China, and its reinfection rate has been high. Numerous studies have examined the effects of meteorological factors involved in HFMD infection. However, no study has investigated the effects on HFMD reinfection. The present study analyzed the relationship between relative humidity and HFMD reinfection. MethodsWe employed a distributed lag nonlinear model to evaluate the relationship between relative humidity and childhood HFMD reinfection in Hefei, China during 2011–2016. This model controlled confounding factors, including seasonality, long-term trend, day of the week, precipitation, and mean temperature. ResultsChildhood HFMD reinfection cases occurred mainly from April to July, and the second peak occurred from October to December. A statistically significant association was observed between relative humidity and HFMD reinfection with delayed effects. The adverse effect of high relative humidity (>75%) appeared later than those of low relative humidity (<75%). Moreover, the highest relative risk (RR 1.08, 95% CI 1.04–1.13) occurred when the relative humidity was 100% and had an 8-day lag. Given the differences between gender and age groups, the effects of extremely high relative humidity on females and those aged ≥4years were higher than those of other groups and caused the highest cumulative relative risks at lag 0–9 or 0–10days (Female: RR 2.00, 95% CI 1.23–3.26; Male: RR 1.55, 95% CI 1.04–2.30; Aged ≥4years: RR 2.31, 95% CI 1.27–4.18; Aged <4years: RR 1.51, 95% CI 1.04–2.20). ConclusionHigh and low relative humidity were found to cause the elevated risks of HFMD reinfection, and the highest risk was observed at extremely high relative humidity. Early warning systems should be built for the protection of susceptible populations, particularly females and children aged ≥4years.

Factores físicos y microbiológicos en el deterioro del huitlacoche en poscosecha

&#x0D; &#x0D; &#x0D; El huitlacoche (Ustilago maydis (DC) Corda) es una buena fuente de aporte de nutrientes en la alimentación. Durante el manejo poscosecha, el producto muestra una rápida senescencia, atribuida a las altas tasas de deshidratación y respiración del producto, además de la composición del mismo. Con la finalidad de prolongar la vida de anaquel, se evaluó el efecto de alta humedad relativa y baja temperatura de almacenamiento sobre las propiedades físicas del huitlacoche (entero y agalla) y la presencia de los hongos fitopatógenos. Los resultados mostraron que a 3 oC la tasa de deshidratación disminuye, manteniendo la calidad visual por más tiempo, tanto del huitlacoche entero como en agalla. El almacenamiento con alta humedad relativa a temperatura ambiente favoreció la proliferación de especies fitopatógenas hospederas como Fusarium oxysporum, Rhizopus stolonifer y Penicillium expansum. La mayor incidencia y severidad la presentó F. oxysporum inoculada con herida en agalla, mientras que R. stolonifer, aunque con menor incidencia que las otras dos especies, fue capaz de sobrevivir hasta 10 oC. Los resultados demuestran que es viable el manejo del huitlacoche a 3 °C y alta humedad relativa en el aire del ambiente, ya que contrarresta la velocidad de deshidratación y elimina el riesgo de proliferación de hongos fitopatógenos hospederos de la superficie.&#x0D; &#x0D; &#x0D;

Short-term effects of meteorological factors on pediatric hand, foot, and mouth disease in Guangdong, China: a multi-city time-series analysis.

BackgroundLiterature shows inconsistency in meteorological effects on Hand, foot, and mouth disease (HFMD) in different cities. This multi-city study aims to investigate the meteorological effects on pediatric HFMD occurrences and the potential effect modification by geographic factors.MethodsBased on daily time-series data in eight major cities in Guangdong, China during 2009–2013, mixed generalized additive models were employed to estimate city-specific meteorological effects on pediatric HFMD. Then, a random-effect multivariate meta-analysis was conducted to obtain the pooled risks and to explore heterogeneity explained by city-level factors.ResultsThere were a total of 400,408 pediatric HFMD cases (children aged 0–14 years old) with an annual incidence rate of 16.6 cases per 1,000 children, clustered in males and children under 3 years old. Daily average temperature was positively associated with pediatric HFMD cases with the highest pooled relative risk (RR) of 1.52 (95 % CI: 1.30–1.77) at the 95th percentile of temperature (30.5 °C) as compared to the median temperature (23.5 °C). Significant non-linear positive effects of high relative humidity were also observed with a 13 % increase (RR = 1.13, 95 % CI: 1.00–1.28) in the risk of HFMD at the 99th percentile of relative humidity (86.9 %) as compared to the median value (78 %). The effect estimates showed geographic variations among the cities which was significantly associated with city’s latitude and longitude with an explained heterogeneity of 32 %.ConclusionsDaily average temperature and relative humidity had non-linear and delayed effects on pediatric HFMD and the effects varied across different cities. These findings provide important evidence for comprehensive understanding of the climatic effects on pediatric HFMD and for the authority to take targeted interventions and measures to control the occurrence and transmission of HFMD.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-016-1846-y) contains supplementary material, which is available to authorized users.

Effect of curing conditions and Ca(OH)2-treated aggregates on mechanical properties of rice husk and hemp concretes using a lime-based binder

This study dealt with the effect of two different processes on the mechanical performances of lightweight insulating plant-based concretes using hemp hurd or rice husk and a lime-based binder. The first process was a lime-water treatment of plant aggregates prior to incorporating them in the mix. The second one consisted in exposing concrete materials to moist curing and elevated temperature.Chemical and textural modifications of plant aggregates after treatment were investigated by infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Compression tests were conducted on concretes using raw or treated aggregates after 28days of curing under standard conditions (20°C–50%RH).Effect of high relative humidity (95%RH) and elevated curing temperature (50°C) was first studied on lime-based mortars. Binder hardening was investigated by means of thermogravimetric analysis (TGA) and back-scattered electron imaging (BSE) on polished cross sections. Then, the same curing process was performed on plant-based concretes and the transition zone between plant aggregates and binder was analyzed by SEM. Compression tests were conducted after 28days for both materials.Results show that lime-water treatment improved compressive strength of rice husk-based concrete but halved that of hemp concrete. As regards the impact of curing conditions, it was shown that compressive strength of hydraulic lime mortars after 28days can be strongly increased with moist curing and elevated temperature. However, plant-based concretes suffer from a high leaching of polysaccharides in the binder and from a transition zone between aggregates and binder of very poor quality when they are subjected to moist curing. This led to unchanged or even lower mechanical performances of plant-based concretes in the case of high RH and elevated temperature compared to 20°C–50%RH.