Toxicological evaluation of protein powder derived from Cupriavidus necator.

Microorganisms have the potential to produce nutrient-rich products that can be consumed as food or feed. The protein-rich powder derived from heat treatment of the whole-cell biomass of polyhydroxybutyrate-deficient Cupriavidus necator, a metabolically versatile organism that uses elements found in the air, is an example of such a product. To assess the safety of the protein powder for use as a nutritional ingredient in human food, in accordance with internationally accepted standards, its genotoxic potential and repeated-dose oral toxicity were investigated. A bacterial reverse mutation test, an in vitro mammalian chromosomal aberration test, and an in vivo mammalian micronucleus test were performed. No evidence of mutagenicity or genotoxicity was found. Additionally, a 90-day repeated-dose oral toxicity study in rats was completed, in which a total of 100 male and female Wistar rats were exposed by gavage to daily doses of 1000, 2000, or 3000 mg/kg bw/day of the test material. Following 90 days of continuous exposure, no mortality or treatment-related adverse effects were observed and no target organs were identified. Therefore, a no observed adverse effect level was determined at 3000 mg/kg bw/day, the highest dose tested.

Impaired exercise capacity in electrostatic polyester powder paint workers.

PURPOSE: Limited number of studies investigated the effects of Electrostatic powder paints (EPP) on human health. We investigated the effects of EPP exposure on lung function, exercise capacity, and quality of life, and the factors determining exercise capacity in EPP workers. METHODS: Fifty-four male EPP workers and 54 age-matched healthy male individuals (control group) were included. Lung function and respiratory muscle strength were measured. The lower limit of normal (LLN) cut-points for FEV1 and FEV1/FVC were calculated. An EPT was used to evaluate bronchial hyperactivity. The handgrip and quadriceps muscle strength were evaluated using a hand-held dynamometer. An ISWT was used to determine exercise capacity. The physical activity level was questioned using the IPAQ. The SGRQ and NHP were used to assessing respiratory specific and general quality of life, respectively. RESULTS: Duration of work, FEV1, MIP, handgrip strength, and ISWT distance were significantly lower, and the change in FEV1 after EPT and %HRmax were significantly higher in the EPP group compared to the control group (p < 0.05). There were no subjects with a < LLN for FEV1 and FEV1/FVC in both groups. In the EPP group, ISWT distance was significantly related to age, height, duration of work, FEV1, change in FEV1 after EPT, MIP, MEP, handgrip strength, IPAQ, SGRQ, and NHP total scores (p < 0.05). The change in FEV1 after EPT, MIP, and duration of work explained % 62 of the variance in the ISWT distance (p < 0.001). CONCLUSIONS: Changes in lung function based on LLN for the FEV1 and FEV1/FVC were not clinically relevant in EPP workers. Exercise capacity is impaired in EPP workers. Degree of exercise-induced bronchospasm, inspiratory muscle strength, and duration of work are the determinants of exercise capacity in EPP workers.

Efficient removal of ginkgotoxin from Ginkgo biloba seed powder by combining endogenous enzymatic hydrolysis with resin adsorption.

BACKGROUND: Ginkgotoxin including 4'-O-methylpyridoxine (MPN) and MPN-5'-glucoside (MPNG) is responsible for Ginkgo seed food poisoning. The purpose of the work reported was to prepare detoxified Ginkgo seed powder and at the same time to retain the nutritional and functional components of Ginkgo seed powder to the maximum extent. RESULTS: Resin adsorption technology was firstly employed to remove ginkgotoxin from water extract of Ginkgo seed powder. Under optimal conditions, the adsorption efficiency of the optimal resin for MPN could reach 100%, and that for MPNG could only reach 85.4 ± 0.93%. Resin adsorption alone could not effectively remove MPN and MPNG simultaneously. Endogenous enzymatic hydrolysis was next attempted to transform MPNG to MPN. MPNG could be completely hydrolyzed to MPN by endogenous enzyme(s) at 40 °C and pH 5.0 in 180 min. Ginkgotoxin only in the form of MPN in the enzymatic hydrolysate was then adsorbed with resin and the conditions were statistically optimized. The adsorption efficiency of MPN reached 98.89 ± 0.99% under the optimized conditions. CONCLUSIONS: Removal of ginkgotoxin by combining endogenous enzymatic hydrolysis with resin adsorption could preserve the main nutritional and functional components of Ginkgo seed powder to the most extent, and did not change its main characteristics. The ginkgotoxin removal method developed in this work is a relatively simple and efficient approach. © 2020 Society of Chemical Industry.

Toxicity assessment of cobalt ferrite nanoparticles on wheat plants.

Cobalt ferrite nanoparticles (NPs) have received increasing attention due to their widespread therapeutic and agricultural applicability. In the environmental field, dry powder- and ferrofluid-suspended cobalt ferrite NPs were found to be useful for removing heavy metals and metalloids from water, while diluted suspensions of cobalt ferrite NP have been promisingly applied in medicine. However, the potential toxicological implications of widespread exposure are still unknown. Since cobalt ferrite NPs are considered residual wastes of environmental or medical applications, plants may serve as a point-of-entry for engineered nanomaterials as a result of consumption of these plants. Thus, the aim of this study was to assess the effects of dry powder and fresh cobalt ferrite NP on wheat plants. Seven-day assays were conducted, using quartz sand as the plant growth substrate. The toxicity end points measured were seed germination, root and shoot lengths, total cobalt (Co) and iron (Fe) accumulation, photosynthetic pigment production, protein (PRT) production, and activities of catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (GPX). Increasing total Co and Fe in plant tissues indicated that wheat plants were exposed to cobalt ferrite NP. Seed germination and shoot length were not sufficiently sensitive toxicity end points. The effective concentration (EC50) that diminished root length of plants by 50% was 1963 mg/kg for fresh ferrite NPs and 5023 mg/kg for powder ferrite NP. Hence, fresh ferrite NPs were more toxic than powder NP. Plant stress was indicated by a significant decrease in photosynthetic pigments. CAT, APX, and GPX antioxidant enzymatic activity suggested the generation of reactive oxygen species and oxidative damage induced by cobalt ferrite NP. More studies are thus necessary to determine whether the benefits of using these NPs outweigh the risks.

Study of lung toxicity in rats exposed to silica powder with different hard metal constituents.

The objective of this study was to assess the lung toxicity induced by the inhalation of different hard metal constituents and silica powder and screen for potential toxicity biomarkers. Rats were randomly divided into saline, cobalt, tungsten carbide, silica, and hard metal (HM) groups and were administered a single 10-mg dose of the respective treatments. After 8 weeks, the lung tissue structure in the HM group was deformed, numerous nucleated giant and epithelial-like cells appeared in the stroma, and the computed tomography scanning images appeared abnormal. Krebs von den Lungen-6 (KL-6), transforming growth factor (TGF)-ß1, and TGF-ß2 expression in bronchoalveolar lavage fluid (BALF) significantly differed between the groups ( p < 0.05). Serum KL-6 and TGF-ß1, but not TGF-ß2, levels significantly differed between some groups ( p < 0.05). We observed multinucleated giant cells in the rat lung tissue. While the serum and BALF levels of KL-6 and TGF-ß2 are not highly specific, TGF-ß1 may be a valuable reference diagnostic marker in HM lung disease.

Assessment of Health Risk from Historical Use of Cosmetic Talcum Powder.

This study's objective is to assess the risk of asbestos-related disease being contracted by past users of cosmetic talcum powder.  To our knowledge, no risk assessment studies using exposure data from historical exposures or chamber simulations have been published. We conducted activity-based sampling with cosmetic talcum powder samples from five opened and previously used containers that are believed to have been first manufactured and sold in the 1960s and 1970s.  These samples had been subject to conflicting claims of asbestos content; samples with the highest claimed asbestos content were tested.  The tests were conducted in simulated-bathroom controlled chambers with volunteers who were talc users.  Air sampling filters were prepared by direct preparation techniques and analyzed by phase contrast microscopy (PCM), transmission electron microscopy (TEM) with energy-dispersive x-ray (EDX) spectra, and selective area diffraction (SAED).  TEM analysis for asbestos resulted in no confirmed asbestos fibers and only a single fiber classified as "ambiguous."  Hypothetical treatment of this fiber as if it were asbestos yields a risk of 9.6 × 10-7 (under one in one million) for a lifetime user of this cosmetic talcum powder.  The exposure levels associated with these results range from zero to levels far below those identified in the epidemiology literature as posing a risk for asbestos-related disease, and substantially below published historical environmental background levels.  The approaches used for this study have potential application to exposure evaluations of other talc or asbestos-containing materials and consumer products.

The no-observed-adverse-effect level (NOAEL) of baby aloe powder (BAP) for nutraceutical application based upon toxicological evaluation.

Aloe has been used in versatile herbal medications and nutraceuticals throughout history. Aloe is widely considered to be generally safe for humans and used globally. The effectiveness and pharmacological properties of aloe are dependent upon when the plant is collected. However, little is known about the toxicology of whole-body aloe collected within less than 1 yr. Based upon widespread exposure to aloe, it is important to determine a daily intake level of this chemical to ensure its safety for humans. To determine the no-observed-adverse-effect level (NOAEL) of baby aloe powder (BAP) for clinical application, Sprague-Dawley (SD) rats were treated orally for 4 wk with 4 different concentrations: 0, 0.125, 0.5, and 2 g/kg body weight (bw). In this study, no significant or dose-dependent toxicological effects of BAP were observed in biochemical or hematological parameters, urinalysis, clinical signs, body weight, and food and water consumption. There were changes in some biomarkers in certain treated groups compared to controls; however, all values were within their reference ranges and not dose-dependent. Based on these results, the NOAEL of BAP was estimated to be greater than 2 g/kg bw in male and 2 g/kg bw in female SD rats. Collectively, these data suggest that BAP used in this study did not produce any marked subacute toxic effects up to a maximum concentration of 2 g/kg bw, and thus use in nutraceuticals and in pharmaceutical and cosmetic applications at a concentration of >2 g/kg is warranted.

Effects of environmental exposure to iron powder on healthy and elastase-exposed mice.

Prolonged exposure to iron powder and other mineral dusts can threaten the health of individuals, especially those with COPD. The goal of this study was to determine how environmental exposure to metal dust from two different mining centers in Brazil affects lung mechanics, inflammation, remodeling and oxidative stress responses in healthy and elastase-exposed mice. This study divided 72 male C57Bl/6 mice into two groups, the summer group and the winter group. These groups were further divided into six groups: control, nonexposed (SAL); nonexposed, given elastase (ELA); exposed to metal powder at a mining company (SAL-L1 and ELA-L1); and exposed to a location three miles away from the mining company (SAL-L2 and ELA-L2) for four weeks. On the 29th day of the protocol, the researchers assessed lung mechanics, bronchoalveolar lavage fluid (BALF), inflammation, remodeling, oxidative stress, macrophage iron and alveolar wall alterations (mean linear intercept-Lm). The Lm was increased in the ELA, ELA-L1 and ELA-L2 groups compared to the SAL group (p < 0.05). There was an increase in the total number of cells and macrophages in the ELA-L1 and ELA-L2 groups compared to the other groups (p < 0.05). Compared to the ELA and SAL groups, the exposed groups (ELA-L1, ELA-L2, SAL-L1, and SAL-L2) exhibited increased expression of IL-1ß, IL-6, IL-10, IL-17, TNF-α, neutrophil elastase, TIMP-1, MMP-9, MMP-12, TGF-ß, collagen fibers, MUC5AC, iNOS, Gp91phox, NFkB and iron positive macrophages (p < 0.05). Although we did not find differences in lung mechanics across all groups, there were low to moderate correlations between inflammation remodeling, oxidative stress and NFkB with elastance, resistance of lung tissue and iron positive macrophages (p < 0.05). Environmental exposure to iron, confirmed by evaluation of iron in alveolar macrophages and in air, exacerbated inflammation, initiated remodeling, and induced oxidative stress responses in exposed mice with and without emphysema. Activation of the iNOS, Gp91phox and NFkB pathways play a role in these changes.

No mutagenicity and oral toxicity of winter mushroom powder treated with atmospheric non-thermal plasma.

This study aimed to evaluate the mutagenicity and oral acute toxicity of winter mushroom powder (PW) treated by atmospheric non-thermal plasma (ANP). Winter mushroom powder without plasma treatment (CW) containing an equivalent amount of sodium nitrite as PW was used as a control. The Ames test revealed that the number of revertant colonies did not significantly increase compared to that in the control. Acute toxicity was assessed in rats that were fed a single dose of winter mushroom powder (5000 mg/kg body weight). Results of the acute toxicity test revealed no remarkable clinical symptoms in any of the rats. No significant difference was observed in of the serum biochemical parameters between the treatments. Regardless of the ANP treatment, mild histological changes were observed in few rats in all groups. Therefore, it is concluded that ANP treatment did not cause any mutagenicity or acute toxicity in the winter mushroom.

Oxysterols in stored powders as potential health hazards.

Cholesterol oxidation products (COPs) have greater biological activity than cholesterol itself. Oxysterols reduce the nutritional value of foods and exhibit a wide range of biological activity, including pro-oxidant, carcinogenic, and cytotoxic properties. The most commonly detected oxysterols in foods are 7α-HC, 7ß-HC, a product of their dehydrogenation 7-KC and α-CE, ß-CE. The main dietary sources of oxysterols are eggs and egg-derived products, thermally processed milk and milk-based products, fried meat. This study aimed to measure the amount of cholesterol oxidation products in milk powder, egg powder and milk-egg powder during 24 months of storage. The changes in the selected oxysterols (determined by gas chromatography) were recorded. In milk powder, after the production process, the amount of cholesterol was 0.2 g 100 g-1 fat and in egg powder it was 3.4 g 100 g-1. After 6 months of storage, the dominant oxysterol in milk and egg powder was 7α-HC and in milk-egg powder it was 7-KC. After the storage period, oxysterols in powdered milk reached 1.81% of total cholesterol.  The most stable cholesterol was in the milk-egg mixture and its oxidation was the slowest. This study showed the presence of COPs in milk powder, egg powder and milk-egg powder and the effect of storage on cholesterol oxidation.

Pulmonary spray dried powders of tobramycin containing sodium stearate to improve aerosolization efficiency.

PURPOSE: Tobramycin microparticulate powders containing the hydrophobic adjunct sodium stearate were studied for their use as pulmonary formulations in dry powder inhalers. METHODS: Spray-dried powders were characterized in terms of particle size distribution, morphology, crystallinity, drug dissolution rate, toxicity on epithelial lung cells and aerosol efficiency. RESULTS: The presence of the sodium stearate had a direct influence on the aerosol performance of tobramycin spray-dried powders. Powders containing 1% w/w sodium stearate had fine particle fraction FPF of 84.3 +/- 2.0% compared to 27.1 +/- 1.9% for powders containing no adjunct. This was attributed to the accumulation of sodium stearate at the particle surface. Powders with higher sodium stearate concentrations (2% w/w) showed significantly lower FPF (66.4 +/- 0.9%) and less accumulation of sodium stearate at the particle surface. This was attributed to the formation of adjunct micelles, which remained internalised in the particle structure due to their reduced tropism toward the drying drop surface and molecular mobility. Preliminary analysis of the toxicity effect of sodium stearate on A549 cell lines showed that the adjunct, in the concentration used, had no effect on cell viability over a 24-h period compared to particles of pure tobramycin. CONCLUSIONS: Tobramycin pulmonary powders with low level of sodium stearate, presenting high respiration performances and no overt toxicity on lung cells, could be used to improve therapeutic outcomes of patient with Cystic Fibrosis (CF).

Involvement of catecholaminergic and GABAAergic mediations in the anxiety-related behavior in long-term powdered diet-fed mice.

Dietary habits are important factors which affect metabolic homeostasis and the development of emotion. We have previously shown that long-term powdered diet feeding in mice increases spontaneous locomotor activity and social interaction (SI) time. Moreover, that diet causes changes in the dopaminergic system, especially increased dopamine turnover and decreased dopamine D4 receptor signals in the frontal cortex. Although the increased SI time indicates low anxiety, the elevated plus maze (EPM) test shows anxiety-related behavior and impulsive behavior. In this study, we investigated whether the powdered diet feeding causes changes in anxiety-related behavior. Mice fed a powdered diet for 17 weeks from weaning were compared with mice fed a standard diet (control). The percentage (%) of open arm time and total number of arm entries were increased in powdered diet-fed mice in the EPM test. We also examined the effects of diazepam, benzodiazepine anti-anxiety drug, bicuculline, GABA-A receptor antagonist, methylphenidate, dopamine transporter (DAT) and noradrenaline transporter (NAT) inhibitor, atomoxetine, selective NAT inhibitor, GBR12909, selective DAT inhibitor, and PD168077, selective dopamine D4 receptor agonist, on the changes of the EPM in powdered diet-fed mice. Methylphenidate and atomoxetine are clinically used to treat attention deficit/hyperactivity disorder (ADHD) symptoms. The % of open arm time in powdered diet-fed mice was decreased by treatments of atomoxetine, methylphenidate and PD168077. Diazepam increased the % of open arm time in control diet-fed mice, but not in powdered diet-fed mice. The powdered diet feeding induced a decrease in GABA transaminase, GABA metabolic enzymes, in the frontal cortex. Moreover, the powdered diet feeding induced an increase in NAT expression, but not DAT expression, in the frontal cortex. These results suggest that the long-term powdered diet feeding may cause low anxiety or impulsivity, possibly via noradrenergic and/or dopaminergic, and GABAAergic mediations and increase the risk for onset of ADHD-like behaviors.

Long-term effect of silver powder in vivo.

The cytotoxicity of silver is a known property of this metal. Interestingly, in the cases of argyria and tattoos, Ag remains in the tissue for a long time without causing harm to the host except pigmentation. To understand these contradictions, pure silver implantation by an original subcutaneous injection method was performed. Two sizes of silver powder particles were implanted subcutaneously: 100 nm (P-silver) and the maximum 45 microm (G-silver). The sulfuration of silver and histopathologic changes were observed for a year. Results were as follows: silver affected the host in the case of P-silver to a greater extent than in G-silver, especially on the 7th day and after 2-4 weeks. Nonetheless, the effect of silver weakened at 12 months after implantation. The presence of P-silver caused various histological reactions, while the decline of silver effect on the host was correlated with an increase in the sulfuration of silver.

Proximal Composition, Nutraceutical Properties, and Acute Toxicity Study of Culinary-Medicinal Oyster Mushroom Powder, Pleurotus ostreatus (Agaricomycetes).

A compositional study was performed on fruiting-body powder of the culinary-medicinal oyster mushroom Pleurotus ostreatus for applications as a nutraceutical/functional food. Carbohydrates (55 g/100 g dry weight [dw]) and proteins (27.45 g/100 g dw, with an in vitro digestibility of 75%) appear to be the major components, but fat content was low (4 g/100 g dw). Pleurotus powder has important micronutrients such as minerals (Fe, Cu, Zn, Mn, Mg, and Co) and ascorbic acid, as well as nonnutrients (i.e., phenolics) with antioxidant potential. A powder-derived aqueous extract had a phenolic compound content of 138 mg/100 g that showed 2,2-diphenyl-1-picrylhydrazyl radical scavenging and inhibition of membrane-lipid peroxidation activities of 58.3% and 61.4%, respectively. The presence of ß-1,3-1,6-D-glucans was also demonstrated (1.54 g/100 g). An acute toxicity test proved that Pleurotus powder was safe after oral administration to both male and female mice at a dose of 2000 mg/kg. The combination of rich nutritional composition, bioactivity, and safety in P. ostreatus fruiting-body powder highlights its potential as a nutraceutical agent promoting health and life quality.

Safety evaluation of a milk-based protein powder produced by a novel manufacturing technique.

TruActive™ NF is a novel, fat-free, milk-based protein powder to be added to food to increase protein content and is manufactured using non-thermal treatment to reduce potential pathogens most relevant to protecting public health. TruActive™ NF was evaluated for potential pathogens of concern to public health regulators; none were detected. The estimated daily intake (EDI) of TruActive™ NF at a 90th percentile consumption for the powder in nutritional beverages and bars is 14,700 mg/day. In vitro genotoxicity testing revealed that concentrations of TruActive™ NF up to 5000 µg/plate did not induce point mutations in selected strains. Oral administration of TruActive™ NF to male Sprague-Dawley rats in an in vivo mammalian chromosomal aberration assay did not induce chromosomal aberrations or significantly affect mitosis in bone marrow cells at 2000 mg/kg. Male and female Sprague-Dawley rats were administered TruActive™ NF at concentrations of 7.5%, 15%, and 30% of the diet during a 28-day subacute dietary study followed by a 14-day recovery period. Some parameters were altered at the 30% diet concentration. The No Observed Adverse Effect Level (NOAEL) in the 28-day dietary study was at 15% of the diet (11,812 mg/kg bw/day for male rats and 11,521 mg/kg bw/day for female rats).

Acute toxicity of nano- and micro-scale zinc powder in healthy adult mice.

The purpose of this study is to evaluate the acute toxicity of oral exposure to nanoscale zinc powder in mice. The healthy adult male and female mice were gastro-intestinally administered at a dose of 5 g/kg body weight with two size particles, nanoscale zinc (N-Zn) and microscale zinc (M-Zn) powder, while one group mice treated with sodium carboxy methyl cellulose was used as the control. The symptoms and mortality after zinc powder treatment were recorded. The effects of particles on the blood-element, the serum biochemical level and the blood coagulation were studied after 2 weeks of administration. The organs were collected for histopathological examination. The N-Zn treated mice showed more severe symptoms of lethargy, vomiting and diarrhea in the beginning days than the M-Zn mice. Deaths of two mice occurred in the N-Zn group after the first week of treatment. The mortalities were confirmed by intestinal obstruction of the nanoscale zinc aggregation. The biochemical liver function tests of serum showed significantly elevated ALT, AST, ALP, and LDH in the M-Zn mice and ALT, ALP, and LDH in the N-Zn mice compared with the controls (P<0.05), which indicated that the liver damage was probably induced by both micro- and nano-scale zinc powders. The clinical changes were observed in the two treated group mice as well. The levels of the above enzymes were generally higher in the M-Zn mice than in the N-Zn mice, which implied that M-Zn powder could induce more severe liver damage than N-Zn. The biochemical renal function tests of serum BUN and CR in the M-Zn mice markedly increased either compared with the N-Zn mice or with the controls (P<0.05), but no significant difference was found between the N-Zn and the control mice. However, severe renal lesions were found by the renal histopathological examination in the N-Zn exposed mice. Therefore, we concluded that severe renal damage could occur in the N-Zn treated mice, though no significant change of blood biochemical levels occurred. Blood-element test showed that in the N-Zn mice, PLT and RDW-CV significantly increased, and HGB and HCT significantly decreased compared to the controls, which indicated that N-Zn powder could cause severe anemia. Besides the pathological lesions in the liver, renal, and heart tissue, only slight stomach and intestinal inflammation was found in all the zinc treated mice, without significant pathological changes in other organs.

Skin injuries caused by new riot control agent used against civilians on the West Bank.

A new riot control agent, used by the Israeli army against civilians protesting about the Separation Wall on the West Bank, has been reported as causing severe skin injuries. We obtained one of the munitions and have identified the contents as capsaicin with an inert carrier and a dispersal agent. This corresponds to the commercially available 'Pepperball Tactical Powder'. Skin injuries of the severity described have not previously been reported with this agent, and would be difficult to manage for clinicians who were unaware of the nature of the agent.

Lung function and dust in climbing halls: two pilot studies.

In climbing halls, high levels of dust are found because magnesia powder is used to dry hands. Concerns have been raised about possible health effects after reports from asthmatics experiencing worsening of symptoms while or after climbing. We investigated acute and sub-acute effects of climbing in dusty halls on lung function in two pilot studies. The first study examined 109 climbers before and after a climbing activity that lasted at least 1 h. In the second study, 25 climbers from different age classes participated in a 2-day climbing competition. Of these, 24 agreed to take part in our investigation, but only 22 provided valid lung function tests on both days. The climbers underwent lung function tests before the first round of the competition (in the morning), after the second round approximately 3 h later and in the morning of the second day before the competition started again. In the first study, we found acute effects, a decline in lung function immediately after the exposure, likely due to protective reflexes of the bronchial muscles and stronger declines in persons with higher exhaled nitric oxide (NO) pre-climbing. In the second study, we also expected sub-acute effects on the next day due to inflammation. On the first day of the competition (second study), dust levels at a central monitor increased over time in a linear manner. Most of the dust was in the size range between 2.5 and 10 µm and dust levels of particulate matter (PM10) reached 0.5 mg/m3. There was a decline in lung function over 24 h in persons with higher exhaled NO levels pre-exposure. All spirometric parameters were affected though the effects were not statistically significant in all cases. Younger age classes started earlier in the morning. Because of the increasing trend in dust levels we expected stronger effects with higher numbers but for the acute effects the reverse was true, possibly because younger climbers use magnesia more or with less experience thus causing higher individual exposure. No differences by age or by time of the first climb were observed for the 24-h lung function change.

Comparison on the Surface Structure Properties along with Fe(II) and Mn(II) Removal Characteristics of Rice Husk Ash, Inactive Saccharomyces cerevisiae Powder, and Rice Husk.

This study selected solid wastes, such as rice husk ash (RHA), inactive Saccharomyces cerevisiae powder (ISP), and rice husk (RH), as the potential adsorbents for the removal of Fe(II) and Mn(II) in aqueous solution. The structural characteristics, functional groups, and elemental compositions were determined by scanning electron microscope (SEM) and Fourier translation infrared spectrum (FT-IR) analyses, respectively. Then the influence on the Fe(II) and Mn(II) removing efficiency by the factors, such as pH, adsorbent dosage, initial Fe(II) and Mn(II) concentration, and contact time, was investigated by the static batch test. The adsorption isotherm study results show that Langmuir equation can better fit the Fe(II) and Mn(II) adsorption process by the three adsorbents. The maximum adsorption amounts for Fe(II) were 6.211 mg/g, 4.464 mg/g, and 4.049 mg/g by RHA, ISP, and RH and for Mn(II) were 3.016 mg/g, 2.229 mg/g, and 1.889 mg/g, respectively. The adsorption kinetics results show that the pseudo-second-order kinetic model can better fit the Fe(II) and Mn(II) adsorption process. D-R model and thermodynamic parameters hint that the adsorption processes of Fe(II) and Mn(II) on the three adsorbents took place physically and the processes were feasible, spontaneous, and exothermic.