moisture content
Dotaz
Zobrazit nápovědu
Dry skin is a common condition that is experienced by many. Besides being particularly present during the cold season, various diseases exist all year round, leading to localized xerosis. To prevent it, the skin is provided with natural moisturizing factors (NMFs). They are small amino acids or derivatives found in the outermost layer of the skin, the stratum corneum (SC). They are often claimed to be highly efficient humectants, increasing the water content to maintain the fluidity of the skin. However, alternative mechanisms have been proposed, suggesting that NMFs themselves may act as lipid mobility amplifiers. This work aims at investigating the role of three NMFs, namely, urea (URE), glycerol (GLY), and urocanic acid/urocanate (UCA/UCO) in SC in silico models, considering two different levels of humidity. Molecular dynamic simulations showed an increase in the diffusion of different lipid components, mainly free fatty acids (FFAs) and ceramide acyl chain moieties, in the presence of either high water content or NMFs. The membrane properties were modified, as seen by an increased thickness and greater lateral stiffness. All NMFs exhibited a similar impact, whereas UCA revealed slight differences according to its charged state. By studying NMF-water intermolecular interactions, we highlighted the role of NMF as a regulator of membrane perturbations while ensuring membrane fluidity. This role allows NMFs to prevent destabilization of the skin membrane in the presence of high water content. This study, performed at an atomistic resolution, highlighted a strong H-bond network between lipids involving mainly ceramides but also all other components. This network can be modified in the presence of a high water concentration or NMFs, resulting in modifications of membrane properties, rationalizing hydration effects.
- MeSH
- glycerol * chemie MeSH
- kůže * chemie metabolismus MeSH
- kyselina urokanová chemie metabolismus MeSH
- lidé MeSH
- močovina * chemie MeSH
- simulace molekulární dynamiky * MeSH
- voda * chemie MeSH
- vodíková vazba * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Alginate lyases have countless potential for application in industries and medicine particularly as an appealing biocatalyst for the production of biofuels and bioactive oligosaccharides. Solid-state fermentation (SSF) allows improved production of enzymes and consumes less energy compared to submerged fermentation. Seaweeds can serve as the most promising biomass for the production of biochemicals. Alginate present in the seaweed can be used by alginate lyase-producing bacteria to support growth and can secrete alginate lyase. In this perspective, the current study was directed on the bioprocessing of brown seaweeds for the production of alginate lyase using marine bacterial isolate. A novel alginate-degrading marine bacterium Enterobacter tabaci RAU2C which was previously isolated in the laboratory was used for the production of alginate lyase using Sargassum swartzii as a low-cost solid substrate. Process parameters such as inoculum incubation period and moisture content were optimized for alginate lyase production. SSF resulted in 33.56 U/mL of alginate lyase under the static condition maintained with 75% moisture after 4 days. Further, the effect of different buffers, pH, and temperature on alginate lyase activity was also analyzed. An increase in alginate lyase activity was observed with an increase in moisture content from 60 to 75%. Maximum enzyme activity was perceived with phosphate buffer at pH 7 and 37 °C. Further, the residual biomass after SSF could be employed as biofertilizer for plant growth promotion based on the preliminary analysis. To our knowledge, this is the first report stating the usage of seaweed biomass as a substrate for the production of alginate lyase using solid-state fermentation.
- MeSH
- algináty * metabolismus MeSH
- biomasa MeSH
- Enterobacter * metabolismus enzymologie izolace a purifikace růst a vývoj MeSH
- fermentace * MeSH
- koncentrace vodíkových iontů MeSH
- kyselina glukuronová metabolismus MeSH
- mořské řasy * mikrobiologie MeSH
- Phaeophyceae mikrobiologie MeSH
- polysacharid-lyasy * metabolismus MeSH
- Sargassum * mikrobiologie metabolismus MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
Probiotics have been used in human and veterinary medicine to increase resistance to pathogens and provide protection against external impacts for many years. Pathogens are often transmitted to humans through animal product consumption. Therefore, it is assumed that probiotics protecting animals may also protect the humans who consume them. Many tested strains of probiotic bacteria can be used for individualized therapy. The recently isolated Lactobacillus plantarum R2 BiocenolTM has proven to be preferential in aquaculture, and potential benefits in humans are expected. A simple oral dosage form should be developed to test this hypothesis by a suitable preparation method, i.e., lyophilization, allowing the bacteria to survive longer. Lyophilizates were formed from silicates (Neusilin® NS2N; US2), cellulose derivates (Avicel® PH-101), and saccharides (inulin; saccharose; modified starch® 1500). They were evaluated for their physicochemical properties (pH leachate, moisture content, water absorption, wetting time, DSC tests, densities, and flow properties); their bacterial viability was determined in conditions including relevant studies over 6 months at 4 °C and scanned under an electron microscope. Lyophilizate composed of Neusilin® NS2N and saccharose appeared to be the most advantageous in terms of viability without any significant decrease. Its physicochemical properties are also suitable for capsule encapsulation, subsequent clinical evaluation, and individualized therapy.
- Publikační typ
- časopisecké články MeSH
Production of amylases by fungi under solid-state fermentation is considered the best methodology for commercial scaling that addresses the ever-escalating needs of the worldwide enzyme market. Here response surface methodology (RSM) was used for the optimization of process variables for α-amylase enzyme production from Trichoderma virens using watermelon rinds (WMR) under solid-state fermentation (SSF). The statistical model included four variables, each detected at two levels, followed by model development with partial purification and characterization of α-amylase. The partially purified α-amylase was characterized with regard to optimum pH, temperature, kinetic constant, and substrate specificity. The results indicated that both pH and moisture content had a significant effect (P < 0.05) on α-amylase production (880 U/g) under optimized process conditions at a 3-day incubation time, moisture content of 50%, 30 °C, and pH 6.98. Statistical optimization using RSM showed R2 values of 0.9934, demonstrating the validity of the model. Five α-amylases were separated by using DEAE-Sepharose and characterized with a wide range of optimized pH values (pH 4.5-9.0), temperature optima (40-60 °C), low Km values (2.27-3.3 mg/mL), and high substrate specificity toward large substrates. In conclusion, this study presents an efficient and green approach for utilization of agro-waste for production of the valuable α-amylase enzyme using RSM under SSF. RSM was particularly beneficial for the optimization and analysis of the effective process parameters.
Orodispersible films are an innovative dosage form. Their main advantages are the application comfort and the possibility of personalization. This work aimed to evaluate the influence of different drying times on the properties of orodispersible films of various thicknesses, prepared in two different semisolid extrusion 3D printing setups. In the first experiment, drying times were dependent on the overall print time of each batch. In the second setup, the drying time was set equal according to the longest one. The evaluated parameters were films' weight uniformity, thickness, moisture content, surface pH, disintegration time, hardness, and tensile strength. Upon statistical comparison, significant differences in the moisture content were found, subsequently affecting the disintegration time. Moreover, statistically significant differences in films' mechanical properties (hardness, tensile strength) were also described, proving that moisture content simultaneously affects film plasticity and related properties. In conclusion, a mutual comparison of the manufactured orodispersible films showed that the drying time affects their physical and mechanical properties. The in-process drying setup was proved to be sufficient while allowing quicker manufacturing.
- Publikační typ
- časopisecké články MeSH
Terrain experiments for avalanche survival research require appropriate snow conditions, which may not be available year round. To prepare these experiments and test the protocol, it might be advantageous to test them in a laboratory with a snow model. The aim of the study was to find a material that can be used to simulate snow for studying gas exchange of a person covered with avalanche snow. Three loose porous materials (perlite, wood shavings and polystyrene) were tested in two forms—dry and moisturized. Each volunteer underwent six phases of the experiment in random order (three materials, each dry and moisturized) during experimental breathing into the tested materials. Physiological parameters and fractions of oxygen and carbon dioxide in the airways were recorded continuously. All the materials selected as possible models of the avalanche snow negatively affected gas exchange during the breathing of the volunteers in a very similar extent. The time courses of the recorded parameters were very similar and were bordered from one side by the wet perlite and from the other side by the dry perlite. Therefore, other tested materials may be substituted with perlite with an appropriate water content. From all the tested materials, perlite is the best to simulate avalanche snow because of its homogeneity, reproducibility and easy manipulation.
- MeSH
- dýchání MeSH
- hyperkapnie * MeSH
- laviny * MeSH
- lidé MeSH
- respirační insuficience MeSH
- testování materiálů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
The remediation of a soil contaminated with Zn, Pb and Cd was tested by using biochar (BC), nano zero-valent iron (nZVI) and a combination of these two (BC + nZVI). Each amendment was individually applied to the soil at 2 wt%. We tested the influence of (i) the used amendments, (ii) time, and (iii) soil moisture conditions on the metal availability and soil physico-chemical parameters using various extraction methods, as well as soil pore water samplings. We found that metal availability was mainly affected by pH under the influence of time and water content. Among the tested treatments, BC was the most successful, resulting in the lowest amounts of the target metals in the pore water and the smallest temporal changes in metal concentrations and pH in the soil. The use of nZVI efficiently decreased water-extractable Pb in the short- and long-term. The BC + nZVI treatment also yielded promising results regarding the immobilisation of the studied metals. Time provoked a general decrease in pH, which occasionally increased the available metal concentrations. Raising the soil water content increased the pH and subsequently lowered the available metal concentrations in the pore water. The mechanisms of metal stabilisation were further investigated by SEM/EDS. The results indicated that the used soil amendments enhanced the binding of Zn, Pb, and Cd on Fe/Mn/Al oxides/hydroxides, which in turn resulted in the stabilisation of the target metals.
- MeSH
- dřevěné a živočišné uhlí chemie MeSH
- kadmium analýza MeSH
- látky znečišťující půdu analýza chemie MeSH
- olovo MeSH
- oxidy chemie MeSH
- půda chemie MeSH
- regenerace a remediace životního prostředí metody MeSH
- těžké kovy analýza chemie MeSH
- železo chemie MeSH
- zinek analýza MeSH
- Publikační typ
- časopisecké články MeSH
A woody-biochar was added to waste biomass during a composting process. The resulting compost-char was amended to a metal contaminated soil and two plant species, L. perenne and E. sativa, were grown in a pot experiment to determine 1) plant survival and stress factors, 2) uptake of metals to plants and, 3) chemical characteristics of sampled soils and pore waters. Compost supplemented with biochar after the composting process were also tested, as well as a commercially available compost, for comparison. Co-composting with biochar hastened the composting process, resulting in a composite material of reduced odour, increased maturity, circum-neutral pH and increased moisture retention than compost (increase by 3% of easily removable water content). When amended to the soil, CaCl2 extractable and pore water metals s were reduced by all compost treatments with little influence of biochar addition at any tested dose. Plant growth success was promoted furthest by the addition of co-composted biochar to the test soil, especially in the case of E. sativa. For both tested plant species significant reductions in plant metal concentrations (e.g. 8-times for Zn) were achieved, against the control soil, by compost, regardless of biochar addition. The results of this study demonstrate that the addition of biochar into the composting process can hasten the stability of the resulting compost-char, with more favourable characteristics as a soil amendment/improver than compost alone. This appears achievable whilst also maintaining the provision of available nutrients to soils and the reduction of metal mobility, and improved conditions for plant establishment.
- MeSH
- biodegradace MeSH
- biomasa MeSH
- Brassicaceae chemie růst a vývoj MeSH
- dřevěné a živočišné uhlí chemie MeSH
- dřevo chemie MeSH
- jílek chemie růst a vývoj MeSH
- kompostování * MeSH
- kovy analýza MeSH
- látky znečišťující půdu analýza MeSH
- půda chemie MeSH
- teoretické modely MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Chronic skin exposure to a wet work environment, as well as disinfectants are factors contributing to epidermal barrier damage. This disturbs its protective functions and promotes the development of dermatoses. All these factors occur in the work environment of a laboratory diagnostician. The aim of the paper was to analyze selected skin parameters and skin lesions in the hands of laboratory diagnosticians. MATERIAL AND METHODS: Overall, 50 laboratory diagnosticians employed in a laboratory in Kraków, Poland, took part in the study. After the interview, the skin pH and moisture content were examined. Measurements were performed on the dorsal side of the dominant hand using the Skin-ph-Meter® PH 905 and Corneometer® CM 825 devices. RESULTS: The obtained moisture level values were qualified as dry or very dry skin, and the skin pH was within the reference range. No correlation between the skin pH value and the features examined (professional experience, the number of hours spent in protective gloves during the day, the number of hand washing episodes during the day) was not indicated. The level of skin moisture content seems to positively correlate with the time of wearing gloves. The use of hand moisturizers after each hand washing episode correlated with the level of skin moisture content. CONCLUSIONS: During the COVID-19 pandemic, this professional group has been facing huge challenges, and mental and physical stressors (including wet work environment) will be the source of future occupational diseases. Med Pr. 2020;71(6):725-34.
- MeSH
- COVID-19 prevence a kontrola MeSH
- dermatitida z povolání epidemiologie MeSH
- dermatózy ruky epidemiologie MeSH
- lidé MeSH
- ochranné rukavice statistika a číselné údaje MeSH
- perspiratio insensibilis * MeSH
- pracoviště organizace a řízení MeSH
- pracovní expozice škodlivé účinky statistika a číselné údaje MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Polsko MeSH
Bifidobacterium longum, one of the main microorganisms in the human gut, is used as an adjunct to lactic acid starter cultures or sold as a probiotic product. Therefore, Bifidobacterium longum cell suspensions get freeze-dried with protective additives to prevent activity losses. To date, investigations covering growth and inactivation kinetics of Bifidobacterium longum during the whole process (cultivation, drying, and storage) have been lacking. In this study, the effect of cultivation conditions and shelf temperature as well as the influence of protectants (maltodextrin, glucitol, trehalose) at various concentrations on cell survival during freeze-drying was assessed. Drying was followed by a storage at + 4 °C and + 20 °C for 70 days to evaluate inactivation kinetics. The impact of the different factors was assessed by measuring surival rate and residual moisture content at various points of time over the whole process. In parallel cell membrane integrity and glass transition were determined to reveal inactivation effects. Cultivation strategy had a strong influence on survival with a huge potential for process improvement. A pH of 6.0 at the growth optimum of the strain provides better conditions regarding cell survival after drying than free acidification (non-regulated pH conditions). During the drying step, membrane leakage due to the removal of water is the main reason for the inactivation in this process step. In this study, the highest survival of 49% was obtained with cells dried at + 35 °C shelf temperature with an addition of maltodextrin (75% bacterial dry matter, w/w). The results show that Bifidobacterium longum cells are mostly inactivated during drying, whereas storage conditions at + 4 °C with an addition of 75% BDM maltodextrin relative to bacterial dry mass prevent cell loss completely.
- MeSH
- Bifidobacterium longum růst a vývoj MeSH
- buněčné kultury metody MeSH
- kinetika MeSH
- koncentrace vodíkových iontů MeSH
- kultivační média chemie MeSH
- lidé MeSH
- lyofilizace metody MeSH
- mikrobiální viabilita * MeSH
- polysacharidy MeSH
- probiotika MeSH
- sorbitol MeSH
- teplota MeSH
- trehalosa MeSH
- vysoušení metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
