Polyurethane−urea microcapsules with limonene oil as the active agent were produced by interfacial polymerization, and their suitability for textile applications was studied. Experimental conditions ...for the textile substrates impregnation were based on industrial requirements and set up at laboratory scale using a mini-foulard. The success of the polymerization reaction leading to the formation of the polyurethane−urea shell was checked by Fourier transform infrared spectroscopy. Particle size distributions and morphology of the microcapsules were studied using a particle size analyzer (Coulter LS230), optical microscopy, and scanning electron microscopy. The effectiveness of the textiles impregnation and the durability of the impregnation effect were evaluated by scanning electron microscopy and by headspace/GC/FID. Under the present research, a product was developed and its performance, in regard to industrial requirements, was successfully tested.
The removal of p-nitrophenol (PNP) from wastewater was evaluated by the activated persulfate process using different materials – carbon xerogels (XG), carbon nanotubes (CNT), and activated carbon ...(AC) –, and also using such materials doped with nitrogen (XGM, CNTM and ACM). These carbon materials were impregnated with 2 wt.% of iron and tested in the oxidative process to assess the influence of their textural and surface chemical properties. The carbon-based materials' properties influence the efficiencies of the adsorption and oxidative processes; in adsorption, the materials with higher specific surface areas (SBET), i.e. AC (824 m2/g) and Fe/AC (807 m2/g), have shown to be the most promising (having achieved a PNP removal of about 20%); on the other hand, in the activated persulfate process the carbon or iron-containing carbon materials with the highest mesoporous areas (Smeso) were the preferential ones – XG and Fe/XG, respectively – reaching removals of 47.3% and 75.7% for PNP and 44.9 and 63.3% for TOC, respectively. Moreover, the presence of nitrogen groups on the samples’ surface benefits both processes, being found that PNP degradation and mineralization increase with the nitrogen content. The stability of the best materials (XGM and Fe/XGM) was evaluated during four cycles, being noticed that while XGM lost catalytic activity, the Fe/XGM sample remained stable without leaching of iron. The quantification of intermediate compounds formed during persulfate oxidation was performed, and only oxalic acid was detected, in addition to PNP, being that their contribution to the TOC measured was higher than 99%. Experiments carried out in the presence of radical scavengers proved that only the sulfate radical is present under the acidic conditions used. Complete PNP oxidation and TOC removal of ∼96% were reached for the activated persulfate process, proving to be more attractive than the Fenton one.
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•Carbon materials, doped or not with nitrogen and impregnated with Fe, were prepared.•Textural and chemical surface properties of carbon materials are crucial.•High mesoporosity and presence of N-containing groups improve process efficiency.•N-doped carbon xerogel impregnated with iron (Fe/XGM) is stable and active.•Persulfate activated with Fe/XGM removed 100% of PNP and 96% of TOC.
The effect of surface wettability on fibrinogen adsorption, platelet adhesion and platelet activation was investigated using self-assembled monolayers (SAMs) containing different ratios of longer ...chain methyl- and shorter chain hydroxyl-terminated alkanethiols (C15CH3 vs. C11OH) on gold.
Protein adsorption studies were performed using radiolabeled human fibrinogen (HFG). Platelet adhesion and activation studies with and without pre-adsorbed fibrinogen, albumin and plasma were assessed using scanning electron microscopy (SEM) and a glutaraldehyde-induced fluorescence technique (GIFT). Results demonstrated a linear decrease of HFG adsorption with the increase of OH groups on the monolayer (increase of the hydrophilicity). Platelet adhesion and activation also decrease with increase of hydrophilicity of surface. Concerning SAMs pre-immersed in proteins, fibrinogen adsorption was related with high platelet adhesion and activation. The
passivant effect of albumin on platelet adhesion and activation was only demonstrated on SAMs contained C11OH. When all the blood proteins are present (plasma) platelet adhesion was almost absent on SAMs with 65% and 100% C11OH. This could be explained by the higher albumin affinity of the SAMs with 65% C11OH and the lower total protein adsorption associated with SAMs with 100% C11OH.
Release of Thyme Oil from Polylactide Microcapsules Martins, Isabel M; Rodrigues, Sofia N; Barreiro, Maria F ...
Industrial & engineering chemistry research,
12/2011, Letnik:
50, Številka:
24
Journal Article
Recenzirano
Microencapsulation reveals numerous advantages over conventional applications of flavors or fragrances. Thus, the goal of this work was to study the release rate of thyme oil through the polylactide ...(PLA) microcapsules prepared by coacervation. Microcapsules have spherical shape and a mean particle size of 36 μm. The results show that the release of thymol is faster in the first hour and remains almost constant in the next days. Moreover, it was observed that the release of the polar compounds of thyme oil is faster than the apolar ones. The diffusion coefficient in the first hour of release was 1.39 × 10–15 m2/s for thymol and 5.21 × 10–17 m2/s for p-cymene. For a period of 5 days, diffusion coefficients of 3.81 × 10–17 m2/s for thymol and 1.43 × 10–18 m2/s for cymene were determined. The diffusion of thyme oil from the PLA cross-linked membrane was dependent on the microcapsules morphological characteristics.
The objective of this work is to access the release behavior of thymol and p-cymene used as model core materials with PLA microcapsules. The microcapsules were obtained by a coacervation process ...developed in a previous work and present a spherical shape with mean particle size of 25 and 37 μm for thymol and p-cymene, respectively. The results have shown that the release of thymol and p-cymene is faster in the first hour keeping almost constant in the subsequent days. The diffusion coefficient in the first hour of release was 1.99 × 10–16 m2/s for thymol and 4.34 × 10–16 m2/s for p-cymene. However, the diffusion was slower if considering a period of 5 days being the diffusion coefficients of 3.34 × 10–19 m2/s for thymol and 3.45 × 10–18 m2/s for cymene.
Microencapsulation of thyme oil by coacervation Martins, Isabel M.; Rodrigues, Sofia N.; Barreiro, Filomena ...
Journal of microencapsulation,
12/2009, Letnik:
26, Številka:
8
Journal Article
Recenzirano
Odprti dostop
The objective of this work is to develop a novel coacervation process to produce microcapsules of polylactide (PLA) to encapsulate thyme oil that will be used in cosmetics. The novelty of this ...approach consists of dissolving PLA in dimethylformamide (DMF) which is a good solvent for PLA but in addition has high solubility in water. Upon contact with water, the homogeneous solution of PLA in DMF promotes the precipitation of PLA around the thyme oil core. The produced microcapsules have bimodal particle size distributions in volume with a mean particle size of 40 µm. Microcapsules analysis by microscopy have confirmed the spherical shape, the rough surface and allowed the estimation of the wall thickness around 5 µm. Quantification of the encapsulated thyme oil was performed by gas chromatography and allowed to evaluate the quality of the encapsulated oil and pointed out for a preferential encapsulation of thyme oil apolar compounds.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Estimation of age-at-death of human skeletal remains is important in palaeo-demographic studies since it allows establishing mortality patterns and life conditions. In adult skeletons, this task is ...particularly difficult and presents imprecise results due to not only the frequent poor preservation of the remains but also the broad age ranges achieved. Given their high degree of mineralization and resistance to taphonomic processes, teeth can play an important role here. Of the currently available dental methods to estimate adults’ age, secondary dentine apposition evaluation is a relatively simple, inexpensive, and non-destructive technique, which has proved reliable and accurate. Therefore, the aim of this study is to estimate the age of 33 enslaved African individuals recovered from Valle da Gafaria (Lagos, Portugal, 15th–seventeenth centuries), using the Cameriere method, and to compare the results with those obtained for the postcranial skeleton. Periapical X-rays were taken on 24 upper and 21 lower canines from 21 females, 10 males, and 2 individuals of unknown sex. Age was estimated by measuring the pulp/tooth area ratio of one or two canines. In two poorly preserved individuals, this was the only method that allowed for age estimation. In the other 31 individuals, dental and skeletal age estimates were consistent more frequently when the two canines’ formula was applied (58.3%) than when only one canine was used (42.1%). Overall, dental age was higher than skeletal age, supporting the hypothesis that elder individuals may be rare in archaeological samples due to the unreliability of the skeletal methods.
Graphene's unique physical structure, as well as its chemical and electrical properties, make it ideal for use in sensor technologies. In the past years, novel sensing platforms have been proposed ...with pristine and modified graphene with nanoparticles and polymers. Several of these platforms were used to immobilize biomolecules, such as antibodies, DNA, and enzymes to create highly sensitive and selective biosensors. Strategies to attach these biomolecules onto the surface of graphene have been employed based on its chemical composition. These methods include covalent bonding, such as the coupling of the biomolecules via the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide reactions, and physisorption. In the literature, several detection methods are employed; however, the most common is electrochemical. The main reason for researchers to use this detection approach is because this method is simple, rapid and presents good sensitivity. These biosensors can be particularly useful in life sciences and medicine since in clinical practice, biosensors with high sensitivity and specificity can significantly enhance patient care, early diagnosis of diseases and pathogen detection. In this review, we will present the research conducted with antibodies, DNA molecules and, enzymes to develop biosensors that use graphene and its derivatives as scaffolds to produce effective biosensors able to detect and identify a variety of diseases, pathogens, and biomolecules linked to diseases.
Simultaneous isolation of nucleic acids and proteins from a single biological sample facilitates meaningful data interpretation and reduces time, cost and sampling errors. This is particularly ...relevant for rare human and animal specimens, often scarce, and/or irreplaceable. TRIzol(®) and TRIzol(®)LS are suitable for simultaneous isolation of RNA, DNA and proteins from the same biological sample. These reagents are widely used for RNA and/or DNA isolation, while reports on their use for protein extraction are limited, attributable to technical difficulties in protein solubilisation.
TRIzol(®)LS was used for RNA isolation from 284 human colon cancer samples, including normal colon mucosa, tubulovillous adenomas, and colon carcinomas with proficient and deficient mismatch repair system. TRIzol(®) was used for RNA isolation from human colon cancer cells, from brains of transgenic Alzheimer's disease mice model, and from cultured mouse cortical neurons. Following RNA extraction, the TRIzol(®)-chloroform fractions from human colon cancer samples and from mouse hippocampus and frontal cortex were stored for 2 years and 3 months, respectively, at -80°C until used for protein isolation.Simple modifications to the TRIzol(®) manufacturer's protocol, including Urea:SDS solubilization and sonication, allowed improved protein recovery yield compared to the TRIzol(®) manufacturer's protocol. Following SDS-PAGE and Ponceau and Coomassie staining, recovered proteins displayed wide molecular weight range and staining pattern comparable to those obtainable with commonly used protein extraction protocols. We also show that nuclear and cytosolic proteins can be easily extracted and detected by immunoblotting, and that posttranslational modifications, such as protein phosphorylation, are detectable in proteins recovered from TRIzol(®)-chloroform fractions stored for up to 2 years at -80°C.
We provide a novel approach to improve protein recovery from samples processed for nucleic acid extraction with TRIzol(®) and TRIzol(®)LS compared to the manufacturer`s protocol, allowing downstream immunoblotting and evaluation of steady-state relative protein expression levels. The method was validated in large sets of samples from multiple sources, including human colon cancer and brains of transgenic Alzheimer's disease mice model, stored in TRIzol(®)-chloroform for up to two years. Collectively, we provide a faster and cheaper alternative to the TRIzol(®) manufacturer`s protein extraction protocol, illustrating the high relevance, and wide applicability, of the present protein isolation method for the immunoblot evaluation of steady-state relative protein expression levels in samples from multiple sources, and following prolonged storage.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Aims
Hypertension (HTN) can lead to heart and kidney damage. The gut microbiota has been linked to HTN, although it is difficult to estimate its significance due to the variety of other ...features known to influence HTN. In the present study, we used germ-free (GF) and colonized (COL) littermate mice to quantify the impact of microbial colonization on organ damage in HTN.
Methods and results
4-week-old male GF C57BL/6J littermates were randomized to remain GF or receive microbial colonization. HTN was induced by subcutaneous infusion with angiotensin (Ang) II (1.44 mg/kg/day) and 1% NaCl in the drinking water; sham-treated mice served as control. Renal damage was exacerbated in GF mice, whereas cardiac damage was more comparable between COL and GF, suggesting that the kidney is more sensitive to microbial influence. Multivariate analysis revealed a larger effect of HTN in GF mice. Serum metabolomics demonstrated that the colonization status influences circulating metabolites relevant to HTN. Importantly, GF mice were deficient in anti-inflammatory faecal short-chain fatty acids (SCFA). Flow cytometry showed that the microbiome has an impact on the induction of anti-hypertensive myeloid-derived suppressor cells and pro-inflammatory Th17 cells in HTN. In vitro inducibility of Th17 cells was significantly higher for cells isolated from GF than conventionally raised mice.
Conclusion
The microbial colonization status of mice had potent effects on their phenotypic response to a hypertensive stimulus, and the kidney is a highly microbiota-susceptible target organ in HTN. The magnitude of the pathogenic response in GF mice underscores the role of the microbiome in mediating inflammation in HTN.
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