In situ Profiles of Oxygen Diffusion in SrTiO3: Bulk Behavior and Boundary Effects

Diffusion profiles have been recorded in situ and evaluated using an optical technique. In this way, bulk diffusion coefficients have been reliably and quantitatively measured. It is shown that the values agree with calculations without using adjustable parameters if the coupling of the diffusing species to internal redox changes of the dopants is accounted for. Measurements on single crystals and on bicrystals with and without crack formation provide worthwhile information on the influence of free relaxed surfaces, freshly produced (crack) surfaces, and grain boundaries on the surface reaction rate and diffusional process. The inward diffusion of oxygen via crack surfaces is characterized by enhanced diffusion coefficients.     

Short- and Long-Term Effects of Prenatal Exposure to Iron Oxide Nanoparticles: Influence of Surface Charge and Dose on Developmental and Reproductive Toxicity

Iron oxide nanoparticles (NPs) are commonly utilized for biomedical, industrial, and commercial applications due to their unique properties and potential biocompatibility. However, little is known about how exposure to iron oxide NPs may affect susceptible populations such as pregnant women and developing fetuses. To examine the influence of NP surface-charge and dose on the developmental toxicity of iron oxide NPs, Crl:CD1(ICR) (CD-1) mice were exposed to a single, low (10 mg/kg) or high (100 mg/kg) dose of positively-charged polyethyleneimine-Fe₂O₃-NPs (PEI-NPs), or negatively-charged poly(acrylic acid)-Fe₂O₃-NPs (PAA-NPs) during critical windows of organogenesis (gestation day (GD) 8, 9, or 10). A low dose of NPs, regardless of charge, did not induce toxicity. However, a high exposure led to charge-dependent fetal loss as well as morphological alterations of the uteri (both charges) and testes (positive only) of surviving offspring. Positively-charged PEI-NPs given later in organogenesis resulted in a combination of short-term fetal loss (42%) and long-term alterations in reproduction, including increased fetal loss for second generation matings (mice exposed in utero). Alternatively, negatively-charged PAA-NPs induced fetal loss (22%) earlier in organogenesis to a lesser degree than PEI-NPs with only mild alterations in offspring uterine histology observed in the long-term.     

Ultrafine particles affect the balance of endogenous pro- and anti-inflammatory lipid mediators in the lung: in-vitro and in-vivo studies

ABSTRACT: BACKGROUND: Exposure to ultrafine particles exerts diverse harmful effects including aggravation ofpulmonary diseases like asthma. Recently we demonstrated in a mouse model for allergicairway inflammation that particle-derived oxidative stress plays a crucial role duringaugmentation of allergen-induced lung inflammation by ultrafine carbon particle (UfCP)inhalation. The mechanisms how particle inhalation might change the inflammatory balancein the lungs, leading to accelerated inflammatory reactions, remain unclear. Lipid mediators,known to be immediately generated in response to tissue injury, might be strong candidatesfor priming this particle-triggered change of the inflammatory balance. METHODS: We hypothesize that inhalation of UfCP may disturb the balance of pro- and antiinflammatorylipid mediators in: i) a model for acute allergic pulmonary inflammation,exposing mice for 24 h before allergen challenge to UfCP inhalation (51.7 nm, 507 ìg/m3),and ii) an in-vitro model with primary rat alveolar macrophages (AM) incubated with UfCP(10 ìg/1 x 106 cells/ml) for 1 h. Lungs and AM were analysed for pro- and anti-inflammatorylipid mediators, namely leukotriene B4 (LTB4), prostaglandin E2 (PGE2), 15(S)-hydroxyeicosatetraenoicacid (15(S)-HETE), lipoxin A4 (LXA4) and oxidative stress marker 8-isoprostane by enzyme immunoassays and immunohistochemistry. RESULTS: In non-sensitized mice UfCP exposure induced a light non-significant increase of all lipidmediators. Similarly but significantly in rat AM all lipid mediators were induced alreadywithin 1 h of UfCP stimulation. Also sensitized and challenge mice exposed to filtered airshowed a partially significant increase in all lipid mediators. In sensitized and challengedmice UfCP exposure induced highest significant levels of all lipid mediators in the lungstogether with the peak of allergic airway inflammation on day 7 after UfCP inhalation. Thelevels of LTB4, 8-isoprostane and PGE2 were significantly increased also one day after UfCPexposure. Immunohistochemistry localized highest concentrations of PGE2 especially in AMone day after UfCP exposure. CONCLUSION: Our results suggest that UfCP exposure affects the balance between pro- and antiinflammatorylipid mediators. In allergic mice, where the endogenous balance of pro- andanti-inflammatory mediators is already altered, UfCP exposure aggravates the inflammationand the increase in anti-inflammatory, pro-resolving lipid mediators is insufficient tocounterbalance the extensive inflammatory response. This may be a contributing mechanismthat explains the increased susceptibility of asthmatic patients towards particle exposure.     

Grazing effects on the greenhouse gas balance of a temperate steppe ecosystem

Although a significant fraction of the global soil?Catmosphere exchange of greenhouse gases (GHGs) occurs in semi-arid zones little is known about the magnitude of fluxes in grazed steppe ecosystems and the interference with grazing intensity. In order to assess GHG burdens and to identify options of climate-optimized livestock farming, GHG emissions of sheep grazing in Inner Mongolia steppe were analyzed. Carbon sequestration and field-fluxes of methane (CH₄) and nitrous oxide (N₂O) were measured at a range of steppe sites differing in grazing intensity and management, i.e. ungrazed (UG), ungrazed with hay cutting (HC), lightly grazed (LG), moderately grazed (MG), and heavily grazed (HG). In addition, GHG emissions from enteric fermentation, manure management, and farming inputs (i.e. fossil fuels) were quantified for LG, MG, and HG. Monte Carlo simulation was used to estimate uncertainty. Sheep grazing changed the net GHG balance of the steppe from a significant sink at UG (?1476?±?2481?kg CO_2eq ha^?1?year^?1) to a significant source at MG (2350?±?1723?kg CO_2eq ha^?1?year^?1) and HG (3115?±?2327?kg CO_2eq ha^?1?year^?1). In a similar way, the GHG intensity increased from 8.6?±?79.2?kg CO_2eq?kg^?1 liveweight gain at LG up to 62.2?±?45.8 and 62.6?±?46.7?kg CO_2eq?kg^?1 liveweight gain at MG and HG, respectively. GHG balances were predominantly determined by CO₂ from changes in topsoil organic carbon. In grazing systems, CH₄ from enteric fermentation was the second most important component. The results suggest that sheep grazing under the current management changes this steppe ecosystem from a sink to a source of GHGs and that grazing exclusion holds large potential to restore soil organic carbon stocks and thus to sequester atmospheric CO₂. The balance between grazing intensity and grazing exclusion predominantly determines GHG balances of grass-based sheep farming in this region. Therefore, a high proportion of ungrazed land is most important for reducing GHG balances of sheep farms. This can be either achieved by high grazing intensity on the remaining grazed land or by confined hay feeding of sheep.     

用升华与蒸发联合法干燥食品的物理性质

Drying is an important unit operation in processing of biological resources. The drying process may influence the product properties and quality, which may shrink, break or undergo rheological, physical and biochemical changes. The important parameters responsible for such changes are drying conditions, type of drying technology and residence drying time. Thermal conductivity, thermal-mass diffusivity, enthalpy, porosity and density are the main material property and heat-mass transfer parameters, which are essential for understanding the changes in product quality and for designing and dimensioning the drying processes. In this paper physical properties of food products undergoing a combined sublimation and evaporation were studied. Pieces of vegetables and potatoes were dried in a heat pump fluidized bed dryer at combined modes with temperatures below the freezing point in the beginning and a final drying step at temperatures above the freezing point. Samples of products were tested at different moisture contents with respect to physical properties. Physical properties of leek and potato samples were measured and mass diffusivities were determined from drying kinetic data. Based on bulk density and rehydration measurements it was clearly observed that drying temperature and modes influenced the final product physical properties. The potato cuberun dried with initial atmospheric freeze-drying step had rehydration ability 430% above a run dried only above the freezing point. The average effective mass diffusivity for 5 mm slabs of leek was 0.5×10^-11m^2·s^-1 for the sublimation stage and 2.2×10^-11m^2·s^-1 for the evaooration stage.     

Ischemia-Reperfusion Injuries Assessment during Pancreas Preservation

Maintaining organ viability between donation and transplantation is of critical importance for optimal graft function and survival. To date in pancreas transplantation, static cold storage (SCS) is the most widely practiced method of organ preservation. The first experiments in ex vivo perfusion of the pancreas were performed at the beginning of the 20th century. These perfusions led to organ oedema, hemorrhage, and venous congestion after revascularization. Despite these early hurdles, a number of factors now favor the use of perfusion during preservation: the encouraging results of HMP in kidney transplantation, the development of new perfusion solutions, and the development of organ perfusion machines for the lung, heart, kidneys and liver. This has led to a resurgence of research in machine perfusion for whole organ pancreas preservation. This review highlights the ischemia-reperfusion injuries assessment during ex vivo pancreas perfusion, both for assessment in pre-clinical experimental models as well for future use in the clinic. We evaluated perfusion dynamics, oedema assessment, especially by impedance analysis and MRI, whole organ oxygen consumption, tissue oxygen tension, metabolite concentrations in tissue and perfusate, mitochondrial respiration, cell death, especially by histology, total cell free DNA, caspase activation, and exocrine and endocrine assessment.     

Characterization of Glutathione Peroxidase 4 in Rat Oocytes,Preimplantation Embryos,and Selected Maternal Tissues during Early Development and Implantation

This study aimed to describe glutathione peroxidase 4 (GPx4) in rat oocytes, preimplantation embryos, and female genital organs. After copulation, Sprague Dawley female rats were euthanized with anesthetic on the first (D1), third (D3), and fifth days of pregnancy (D5). Ovaries, oviducts, and uterine horns were removed, and oocytes and preimplantation embryos were obtained. Immunohistochemical, immunofluorescent, and Western blot methods were employed. Using immunofluorescence, we detected GPx4 in both the oocytes and preimplantation embryos. Whereas in the oocytes, GPx4 was homogeneously diffused, in the blastomeres, granules were formed, and in the blastocysts, even clusters were present mainly around the cell nuclei. Employing immunohistochemistry, we detected GPx4 inside the ovary in the corpus luteum, stroma, follicles, and blood vessels. In the oviduct, the enzyme was present in the epithelium, stroma, blood vessels, and smooth muscles. In the uterus, GPx4 was found in the endometrium, myometrium, blood vessels, and stroma. Moreover, we observed GPx4 positive granules in the uterine gland epithelium on D1 and D3 and cytoplasm of fibroblasts forming in the decidua on D5. Western blot showed the highest GPx4 levels in the uterus and the lowest levels in the ovary. Our results show that the GPx4 is necessary as early as in the preimplantation development of a new individual because we detected it in an unfertilized oocyte in a blastocyst and not only after implantation, as was previously thought.     

Influence of Paclitaxel and Doxorubicin Therapy of ßIII-Tubulin,Carbonic Anhydrase IX,and Survivin in Chemically Induced Breast Cancer in Female Rat

Breast cancer is the most common cancer in females. The aim of this study was to determine the effect of paclitaxel (PTX) and doxorubicin (DOX) therapy on the βIII-tubulin, carbonic anhydrase IX (CA IX), and survivin expression in chemically-induced rat mammary tumors. Animals with induced mammary carcinogenesis were randomly divided into treatment groups and an untreated group. The total proportion of tumors, the proportion of carcinoma in situ (CIS), and invasive carcinoma (IC) were evaluated. Protein expression in tumor tissue was determined using IHC. Statistical analysis of the data, evaluated by Fisher-exact test and unpaired t-test. Significantly increased levels of proteins in the tumor cells were confirmed using the IHC method for all studied proteins. The expression of βIII-tubulin, CA IX, and survivin increased significantly after treatment with both cytostatics (PTX and DOX). Depending on the type of tumor, a significant increase in all proteins was observed in IC samples after PTX treatment, and CA IX expression after DOX treatment. In CIS samples, a significant increase of βIII-tubulin and survivin expression was observed after a DOX treatment. The results suggest that βIII-tubulin, survivin, and CA IX may be significant drug resistance markers and the clinical regulation of their activity may be an effective means of reversing this resistance.     

Tuning Interfacial Activity of Polymeric Resin–Surfactant/<Emphasis Type="Italic">n</Emphasis>-Alcohol Solution Interactions

Measurements of surface tension were carried out for several aqueous solutions of different amphiphilic systems. This research studied the interaction between two polymeric resins (more structure definition) (PR) and nonyl phenol ethoxylates (NP) with degrees of ethoxylation varying from 10 to 20 ethylene oxide groups. The results show that in mixtures of PR and NP₂₀EO, the adsorption on the surface was lower, with the molecules tending to remain within the liquid. On the other hand, mixtures of PR and NP₁₀EO have resulted in greater surface adsorption. The effect of the added alcohols was to tune the interfacial activity of the PR as function of the PR and alcohol concentrations. The general tendency of the surface tension curves to decrease with increasing PR/alcohol concentration in solutions was not significantly modified with the addition of alcohols; however, the surface tension values changed due to the addition of alcohols and a model is proposed to explain these changes, as they depend on both alcohol chain length and the PR/alcohol concentration. An emulsion stability test was performed on polymeric resins–surfactant systems to determine the correlation between their surface properties. Nonionic surfactants present in these mixtures are mainly responsible for the emulsion stability. It was concluded that mixtures of the less hydrophilic PR (PR_B) with NP₁₀EO have good interfacial properties, including a high interfacial concentration and a low critical micellar concentration.