Maternal milk contains compounds that may affect newborn immunity. Among these are a group of oligosaccharides that are synthesized in the mammary gland from lactose; these oligosaccharides have been ...termed human milk oligosaccharides (HMOs). The amount of HMOs present in human milk is greater than the amount of protein. In fact, HMOs are the third-most abundant solid component in maternal milk after lactose and lipids, and are thus considered to be key components. The importance of HMOs may be explained by their inhibitory effects on the adhesion of microorganisms to the intestinal mucosa, the growth of pathogens through the production of bacteriocins and organic acids, and the expression of genes that are involved in inflammation. This review begins with short descriptions of the basic structures of HMOs and the gut immune system, continues with the beneficial effects of HMOs shown in cell and animal studies, and it ends with the observational and randomized controlled trials carried out in humans to date, with particular emphasis on their effect on immune system development. HMOs seem to protect breastfed infants against microbial infections. The protective effect has been found to be exerted through cell signaling and cell-to-cell recognition events, enrichment of the protective gut microbiota, the modulation of microbial adhesion, and the invasion of the infant intestinal mucosa. In addition, infants fed formula supplemented with selected HMOs exhibit a pattern of inflammatory cytokines closer to that of exclusively breastfed infants. Unfortunately, the positive effects found in preclinical studies have not been substantiated in the few randomized, double-blinded, multicenter, controlled trials that are available, perhaps partly because these studies focus on aspects other than the immune response (e.g., growth, tolerance, and stool microbiota).
The potential for the positive manipulation of the gut microbiome through the introduction of beneficial microbes, as also known as probiotics, is currently an active area of investigation. The ...FAO/WHO define probiotics as live microorganisms that confer a health benefit to the host when administered in adequate amounts. However, dead bacteria and bacterial molecular components may also exhibit probiotic properties. The results of clinical studies have demonstrated the clinical potential of probiotics in many pathologies, such as allergic diseases, diarrhea, inflammatory bowel disease and viral infection. Several mechanisms have been proposed to explain the beneficial effects of probiotics, most of which involve gene expression regulation in specific tissues, particularly the intestine and liver. Therefore, the modulation of gene expression mediated by probiotics is an important issue that warrants further investigation. In the present paper, we performed a systematic review of the probiotic-mediated modulation of gene expression that is associated with the immune system and inflammation. Between January 1990 to February 2014, Pub Med was searched for articles that were published in English using the Me SH terms "probiotics " and " gene expression " combined with "intestines", "liver", "enterocytes", "antigen-presenting cells", "dendritic cells", "immune system", and "inflammation". Two hundred and five original articles matching these criteria were initially selected, although only those articles that included specific gene expression results(77) were later considered for this review and separated into three major topics: the regulation of immunity and inflammatory gene expression in the gut, in inflammatory diseases of the gut and in the liver. Particular strains of Bifidobacteria, Lactobacilli, Escherichia coli, Propionibacterium, Bacillus and Saccharomyces influence the gene expression of mucins, Toll-like receptors, caspases, nuclear factor-κB, and interleukins and lead mainly to an anti-inflammatory response in cultured enterocytes. In addition, the interaction of commensal bacteria and probiotics with the surface of antigenpresenting cells in vitro results in the downregulation of pro-inflammatory genes that are linked to inflammatory signaling pathways, whereas other anti-inflammatory genes are upregulated. The effects of probiotics have been extensively investigated in animal models ranging from fish to mice, rats and piglets. These bacteria induce a tolerogenic and hyporesponsive immune response in which many genes that are related to the immune system, in particular those genes expressing anti-inflammatory cytokines, are upregulated. By contrast, information related to gene expression in human intestinal cells mediated by the action of probiotics is scarce. There is a need for further clinical studies that evaluate the mechanism of action of probiotics both in healthy humans and in patients with chronic diseases. These types of clinical studies are necessary for addressing the influence of these microorganisms in gene expression for different pathways, particularly thosethat are associated with the immune response,and to better understand the role that probiotics might have in the prevention and treatment of disease.
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•Amine functionalization of carbon nanotubes through plasma using solid-phase urea.•Incorporation of 0.8 at.% of O and 0.5 at.% of N in 1 min of 100 W plasma treatment.•Achievement of ...micro-arc discharge by generating micro holes on TiO2 coated electrode.•Complete water removal from carbon nanotubes through high-density plasma treatment.
Carbon nanotubes (CNTs) were amine-functionalized through treatments in inductively coupled post-discharge, capacitively coupled micro spark and pulsed micro arc/glow discharge plasma regions, using urea in solid state as functionalization agent. In each plasma mode, the CNT functionalization yield was evaluated according to the variation of the plasma power and treatment time. For that, the samples were characterized through Fourier-transform infrared spectroscopy, Raman spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The results show that, while preserving the integrity of the CNTs, an 80% increase in oxygen content and up to 1.2at.% of nitrogen was achieved using an asymmetric bipolar plasma power supply (ABiPPS). The adsorbed water can be completely removed from the CNTs through both a high-plasma-density treatment and a methanol washing procedure, conducted before sample characterization to remove any unreacted urea.
Carbon nanotubes (CNT) were functionalized by radio-frequency plasma using maleic anhydride (MA) as a source of functional groups. The MA insertion was performed in the solid form through a mixture ...with CNT conducted under two different methods: in a planetary mill; and manually, using mortar and pestle assistance. The premix influence on CNT functionalization and the functionalization itself were evaluated using Fourier Transform Infrared (FTIR), Raman Spectroscopy, Transmission Electronic Microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results indicate CNT plasma functionalization by the carboxyl groups provided by the opened MA ring. Neither the mixture methods nor the plasma process affected the integrity of the CNT, maintaining their initial morphology. Structural analyses indicate increased presence of O-C=O groups attached to the CNT's surface after functionalization operation and subsequent moisture removal from the nanoparticles. Such effect was more pronounced for samples with a higher amount of O-C=O groups (>3 at.%) premixed in the mortar, suggesting a potential use of the functionalized CNT as an agent for wastewater cleaning.
•CNT can be plasma-functionalized by solid maleic anhydride (MA).•Manual CNT/MA premix favors O-C=O insertion into the plasma treatment.•Water replacement by methanol in CNT is influenced by the O-C=O quantity in the CNT.•Water can be completely removed when the O-C=O at.% in the CNT is higher than 3.0.
Bacterial cellulose presents itself as an alternative to traditional textiles due to its versatility, aesthetics, mechanical similarity to leather and, most importantly, sustainability in production ...processes. However, its use depends on surface modifications that promote suitable performance in fashion products, due to its high hydrophilicity. A less polluting alternative is the plasma treatment, which does not involve effluents or solid or liquid waste. In this context, this study aims to use the cathodic cage plasma process, an environmentally friendly technique, to reduce the hydrophilic nature of bacterial cellulose for its application in the fashion industry. Samples were produced from kombucha and treated through a modified low-pressure cold plasma system, named cathodic cage plasma. The influence of the gas mixture (Ar/acetylene and Ar/acetylene/H
2
), treatment time and duty cycle was evaluated. The samples were characterized through wetting behavior (contact angle), FTIR, TG and dTG, XPS and FEG-SEM. The cultivated bacterial cellulose exhibited apparent flexibility, roughness, and some transparency. The plasma treatment was proven effective, forming a thin hydrocarbon film on the surface of the BC, sufficient to decrease the hydrophilicity and purify it without degradation. The bacterial cellulose could be made hydrophobic by using parameters such as a longer treatment time, a combination of gases without the addition of hydrogen, and a lower duty cycle (from the most to the least influential factor, respectively). Plasma treatment mitigated the common issues of hydrophilic bacterial cellulose without the need to introduce processes that generate effluents or waste while maintaining the material’s biodegradability.
The active screen plasma system has been extensively studied over the past few years, mainly for plasma nitriding purposes. This technique also provides possibilities of treating non-electrical ...conducting materials, such as polymeric ones, which is unattainable with a conventional DC plasma system. In this work, an active screen plasma setup for maleic anhydride (MA) film deposition on a glass substrate was used. The plasma working gas was a mixture of argon and MA vapour. Films obtained through conventional plasma discharge were compared with the active screen deposition process, in both DC and pulsed-mode plasma. The samples were characterized through Fourier-transform infrared spectroscopy and static contact angle between the film’s surface and droplets of distilled water. Film thickness measurements were performed through profilometry. Results showed that MA films obtained through the active screen system are thicker and more efficiently preserve the anhydride groups than those obtained from conventional plasma discharge.
This study investigated the impact of adding graphene oxide (GO) and iron oxide (II) (Fe3O4) nanoparticles individually and in combination on the morphology, thermo-mechanical, and dielectric ...properties of a Polypropylene/High-Density Polyethylene (PP/HDPE) blend. By adding these nanoparticles separately or as a mixture, we can determine if both mechanisms have a synergistic effect and how they impact the dielectric constant values of their nanocomposites. The nanoparticle mixture was prepared in both an alkaline and a neutral medium. The mixture in the alkaline medium contained lower quantities of iron nanoparticles than in the neutral medium, and they were localized on the surface of GO. The nanocomposites showed significant differences in dynamic-mechanical and dielectric properties. The system with Fe3O4 exhibited a higher storage modulus, while the system with GO had a higher dielectric constant. However, no synergistic effect was observed in the nanoparticle mixtures.
This work aims to investigate how adding functionalized carbon nanotubes (CNTs) to a Polyamide 6/polypropylene blend influences its properties. CNT functionalization was carried on through plasma ...with oxygen (CNT_O
2
) or maleic anhydride (CNT_MA). CNT_O
2
presented the highest amount of oxygen, but, as the treatment time in plasma was twice as long as that of the CNT_MA sample, the oxygenated groups, for the most part, tended to formed lactones. On the other hand, plasma treatment with maleic anhydride was more efficient to insert carboxylic groups onto the CNT surface. Adding non-functionalized CNT in the blend, an elongation of PP phase was observed. In the functionalized CNT nanocomposites, a significant decrease in phase size was observed. No improvement in adhesion between phases was observed. Crystallinity degree decreased when non-functionalized CNT was added and increased with functionalized CNT. Despite the greater interaction between amorphous and crystalline regions observed in nanocomposites with CNT_O
2
, the highest values of storage module came from CNT_MA nanocomposite. The COOH groups on the CNT surface reacted with the polyamide, improving tension transfer between phases and leading to a better performance in blend mechanical properties.
Polyaniline is synthetized on carbon fiber through electrolytic plasma applied in an acid monomer solution, without an oxidant. Pulsed‐plasma carbon fiber surface treatment is performed with two ...1.0 kV pulses for 1 µs with an 200 µs off period. Different treatment times and ultrasound presence, to create microbubbles that can help plasma formation, are tested. The ultrasonic bath is not effective to produce higher quantities of polymer. Furthermore, the film formed on the carbon fiber is chemically characterized through treatment in a basic solution followed by immersion in NMP, and through FT‐IR and XPS. The presence of nitrogen in the carbon fiber surface and the characteristic FT‐IR bands of delocalized electrons indicate that the electrolytic plasma treatment is efficient to synthesize polyaniline in its conducting form. Electrochemical activity is accessed by cyclic voltammetry, indicating the formation of electrodes with good reversibility and stability, thereby suitable for supercapacitor applications.
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