A thermal protocol is reported for the formal insertion of nitric acid into aryldiazoacetates using Fe(NO3)3·9H2O. This strategy is mild and high yielding and allows the preparation of a large ...variety of members of an unprecedented family of organic nitrates. The nitrate group can be also readily transformed into other functional groups and heterocyclic moieties and can possibly allow new biological explorations of untapped potential associated with their NO-releasing ability.
•Deodorized fish oil rich in PUFA from tuna heads by enzymatic hydrolysis was produced.•Physicochemical characterization and fatty acid profile were determined.•The fatty acid profile of the oil ...samples was determined by chromatography.•Panelists scored for odor profile using QDA of the deodorized oil in seven trials.•Temperature and chemical reagents in the refining influenced the fatty acid profile.
In this study, the effects of chemical refining and deodorization on fatty acid profiles and physicochemical and sensory characteristics of the tuna by-product oil obtained by enzymatic hydrolysis were evaluated. Enzymatic extraction was conducted for 120min at 60°C and pH 6.5 using Alcalase at an enzyme–substrate ratio of 1:200 w/w. The chemical refining of crude oil consisted of degumming, neutralization, washing, drying, bleaching, and deodorization; deodorization was conducted at different temperatures and processing times. Although chemical refining was successful, temperature and chemical reagents favored the removal of polyunsaturated fatty acids (PUFA) from the oil. Aroma attributes of fishy odor, frying odor, and rancid odor predominantly contributed to the sensory evaluation of the product. Deodorization conditions of 160°C for 1h and 200°C for 1h were recommended for the tuna by-product oil, which is rich in PUFA.
Product scarcity can influence purchase decisions, but this relationship is multifaceted due to the influence of various cues. This study aims to integrate knowledge of this subject through a ...meta‐analysis. The findings suggest that the likelihood of purchasing a scarce product is greater under (i) scarcity conditions of excessive demand (rather than restricted supply) and variety (rather than a category), but not urgency (limited quantity and limited time) scarcity, and (ii) product conditions of enduring luxuries (as opposed to transitory luxuries) and the presence (rather than absence) of social signaling and seasonality. From a theoretical standpoint, this study offers a typology of product and scarcity cues and employs a meta‐analysis to enhance our understanding of the relationships between product scarcity, product and scarcity cues, and purchase decisions, resulting in the establishment of a heterogeneous theory of product scarcity. From a managerial standpoint, the study suggests that product scarcity can affect purchase decisions and can be ethically utilized as a marketing strategy.
The present study performed geochemical fractioning of major and minor elements in a cross-shelf gradient of the Abrolhos Bank, where the largest and most diverse coral reefs in the South Atlantic ...are concentrated. The fractioning was performed using sequential extractions to determine the degree of availability and toxicity of the elements. The mobility pattern of the elements investigated were in the following order: Ca > Mn > Pb > Cr > Zn > Fe > V > Cu > Ba>Al > Ni > Ti. For elements, such as (Ti, Ni, Al, Ba, Cu, V, Fe, Zn, Cr, Pb), the highest concentrations were in the residual phase at some sampling sites. As established by Environment Canada (Threshold Effect Level - TEL and Probable Effect Level - PEL), Ba, Cr, and Ni produced values higher than the limits, associated with higher concentrations of other elements. In addition, significant proportions of these elements were found in mobile phases in the same sites. Thus, more rigorous measures are critical to avoid alarming levels of chronic environmental pollution inside and outside protected areas of the region. To enhance the sustainability of the region, more effective enforcement is crucial to prevent anthropic contamination that may threaten its biodiversity. The results provide the baseline for future studies regarding the potential impacts of the breach of the tailings dam in the region of Mariana, Minas Gerais.
Display omitted
•Metals were evaluated in surface sediments before the impact of ore tailings dams.•Oxidizable phase elements were related with Corg indicating potential bioavailability.•Mobility levels of metals were in the order of Ca > Mn > Pb > Cr > Zn > Fe > V > Cu > Ba>Al > Ni > Ti.•The concentrations of Ba, Ni, and Cr were above the TEL in three conservation units.•Antropogenic sources increase metal concentration in Santa Barbara Island.
Display omitted
•A polysulfhydrylated polyester (PSPE) was synthesized.•The PSPE forms hydrolysable blends with PCL.•S-nitrosation of blended PCL/PSPE films generates surface NO-releasing SNO ...groups.•Topical S-nitrosated PCL/PSPE films promotes dose-response dermal vasodilation.•PCL/PSPE blend is a potential platform for topical or implantable biomaterials.
Polymeric biomaterials for implantable medical devices are subject to demands that go beyond passive biocompatibility. Inhibition of thrombus formation, reduced inflammatory response and the eventual complete bioabsorption of the implant are central challenges for emerging polymeric biomaterials. Nitric oxide (NO) released at the biomaterial/tissue interface may inhibit platelet adhesion and improve tissue integration in blood-contacting/implanted devices. In addition, local NO release may increase vasodilation, thereby improving ischemic conditions in topical applications. In this study, we present a novel degradable NO-releasing polymeric platform based on blended poly-ε-caprolactone (PCL)/polysulfhydrylated polyester (PSPE). PCL formed miscible blends with PSPE up to 45 wt% of PSPE. S-nitrosation of the PCL/PSPE blends converted the surface PSPE component into a NO-releasing polynitrosated polyester (PNPE). Real-time chemiluminescence NO detection showed that blends with different PCL:PSPE ratios allow surface S-nitrosothiol concentrations in the range of 0.5–1.5 μmol/cm2. Topical application of blended PCL/PNPE films on the healthy skin led to a 6–10-fold increase in the skin blood flow due to local NO delivery, as shown by in vivo laser-Doppler flowmetry. Blended PCL/PSPE films displayed higher hydrophilicity and a 2–11-fold increase in the hydrolytic mass loss, compared to pure PCL films. Therefore, PCL/PSPE blend is a potential biomaterial platform for local NO delivery and more quickly degradable biomedical devices.
The co-inoculation of soybean with
and other plant growth-promoting rhizobacteria (PGPR) is considered a promising technology. However, there has been little quantitative analysis of the effects of ...this technique on yield variables. In this context, the present study aiming to provide a quantification of the effects of the co-inoculation of
and PGPR on the soybean crop using a meta-analysis approach.
A total of 42 published articles were examined, all of which considered the effects of co-inoculation of PGPR and
on the number of nodules, nodule biomass, root biomass, shoot biomass, shoot nitrogen content, and grain yield of soybean. We also determined whether the genus of the PGPR used as co-inoculant, as well as the experimental conditions, altered the effect size of the PGPR.
The co-inoculation technology resulted in a significant increase in nodule number (11.40%), nodule biomass (6.47%), root biomass (12.84%), and shoot biomass (6.53%). Despite these positive results, no significant increase was observed in shoot nitrogen content and grain yield. The response of the co-inoculation varied according to the PGPR genus used as co-inoculant, as well as with the experimental conditions. In general, the genera
,
, and
were more effective than
. Overall, the observed increments were more pronounced under pot than that of field conditions. Collectively, this study summarize that co-inoculation improves plant development and increases nodulation, which may be important in overcoming nutritional limitations and potential stresses during the plant growth cycle, even though significant increases in grain yield have not been evidenced by this data meta-analysis.
Display omitted
Topical nitric oxide (NO) delivery has been shown to accelerate wound healing. However, delivering NO to wounds at appropriate rates and doses requires new biomaterial-based ...strategies. Here, we describe the development of supramolecular interpolymer complex hydrogels comprising PEO-PPO-PEO (F127) micelles embedded in a poly(acrylic acid) (PAA) matrix, with S-nitrosoglutathione (GSNO) molecules dissolved in the hydrophilic domain. We show that PAA:F127/GSNO hydrogels start releasing NO upon hydration at rates controlled by their rates of water absorption. SAXS measurements indicate that the supramolecular structure of the hydrogels retains long-range order domains of F127 micelles. The PAA/F1227 hydrogels displayed dense morphologies and reduced rates of hydration. The NO release rates remain constant over the first 200 min, are directly correlated with the hydration rates of the PAA:F127/GSNO hydrogels, and can be modulated in the range of 40 nmol/g h to 1.5 μmol/g h by changing the PAA:F127 mass ratio. Long-term NO-release profiles over 5 days are governed by the first-order exponential decay of GSNO, with half-lives in the range of 0.5–3.4 days. A preliminary in vivo study on full-thickness excisional wounds in mice showed that topical NO release from the PAA:F127/GSNO hydrogels is triggered by exudate absorption and leads to increased angiogenesis and collagen fiber organization, as well as TGF-β, IGF-1, SDF-1, and IL-10 gene expressions in the cicatricial tissue. In summary, these results suggest that hydration-controlled NO release from topical PAA:F127/GSNO hydrogels is a potential strategy for enhancing wound healing.
The topical delivery of nitric oxide (NO) to wounds may provide significant beneficial results and represent a promising strategy to treat chronic wounds. However, wound dressings capable of releasing NO after application and allowing the modulation of NO release rates, demand new platforms. Here, we describe a novel strategy to overcome these challenges, based on the use of supramolecular poly(acrylic acid) (PAA):F127 hydrogels charged with the NO donor S-nitrosoglutathione (GSNO) from whereby the NO release can be triggered by exudate absorption and delivered to the wound at rates controlled by the PAA:F127 mass ratio. Preliminary in vivo results offer a proof of concept for this strategy by demonstrating increased angiogenesis; collagen fibers organization; and TGF-β, IGF-1, SDF-1, and IL-10 gene expressions in the cicatricial tissue after topical treatment with a PAA:F127/GSNO hydrogel.
S‐nitrosothiols (RSNOs) are nitric oxide (NO) donor molecules with potential biomedical applications since they mimic NO biological functions, such as vasodilation and inflammatory process ...regulation. In this work, chitosan (CS), a natural biopolymer widely used as a biomaterial, is functionalized with thioglycolic acid (TGA) or mercaptosuccinic acid (MSA) in reactions mediated by a carbodiimide, yielding CS with thiol contents of 88 µmol g–1 (CS‐TGA) and 126 µmol g–1 (CS‐MSA). The subsequent S‐nitrosation of CS‐TGA and CS‐MSA generates the corresponding S‐nitroso derivatives, CS‐TGA(SNO) and CS‐MSA(SNO). The UV–Vis spectral changes associated with the S‐NO bond cleavage of CS‐TGA(SNO) and CS‐MSA(SNO), monitored in solution over 18 days of storage in a common refrigerator, reveal that these S‐nitroso CS derivatives display enhanced thermal stability in the dark, with half‐life values of 36.1 for CS‐TGA(SNO) and 16.1 days for CS‐MSA(SNO). Conversely, CS‐TGA(SNO) and CS‐MSA(SNO) can release NO photochemically on‐demand under visible light irradiation in a first‐order process triggered by photon absorption that leads to a half‐life of 33 min for both S‐nitroso CS. These results show that CS‐TGA(SNO) and CS‐MSA(SNO) may emerge as new CS‐based biomaterials for providing light‐triggered local NO release in biomedical applications.
3D printing has emerged as a first‐line approach for the fabrication of complex structures. In the biomedical field, extrusion‐based is the most popular printing technique. However, a limited range ...of biocompatible printable inks is available for this technique because, typically, low‐viscosity inks are not printable, or the resulting constructs are unable to self‐support. In this work, use of the Freeform Reversible Embedding of Suspended Hydrogels (FRESH) extrusion‐based technique to fabricate self‐supported 3D constructs from low‐viscosity polysaccharide inks composed of methacrylated hyaluronic acid (HA(GM)) and methacrylated pectin (PEC(GM)) is aimed. The use of a support bath of gelatin slurry to sustain the extruded filaments during both printing and post curing allows reaching a shape fidelity so far unreported for low‐viscosity polysaccharide inks. Moreover, the methacrylate groups of HA(GM) and PEC(GM) lead to double crosslinked hydrogels, where the calcium ions added to the gelatin slurry promote the ionotropic gelation of PEC(GM), while the methacrylate groups of both PEC(GM) and HA(GM) promote their photocrosslinking after UV irradiation. The resulting 3D constructs exhibit elastic modulus in the range of 0.5–2.3 kPa, which is suitable for the 3D printing of constructs for soft tissue repair or substitution.
•PVA films functionalized with nitric oxide releasing SNO groups were prepared.•PVA-SNO films were combined with a layer of micellar Pluronic F127 hydrogel.•Combined PVA-SNO films/F127 hydrogel ...reduced the rate of NO delivery to tissues.•Topical application of PVA-SNO films/F127 hydrogel improved wound healing.•A new approach for NO-releasing active wound dressings is proposed.
Nitric oxide (NO) releasing biomaterials represent a potential strategy for use as active wound dressings capable of accelerating wound healing. Topical NO-releasing poly(vinyl alcohol) (PVA) films and Pluronic F127 hydrogels (F127) have already exhibited effective skin vasodilation and wound healing actions. In this study, we functionalized PVA films with SNO groups via esterification with a mixture of mercaptosucinic acid (MSA) and thiolactic acid (TLA) followed by S-nitrosation of the SH moieties. These films were combined with an underlying layer of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide), i.e., PEO-PPO-PEO (Pluronic F127) hydrogel and used for the topical treatment of skin lesions in an animal model. The mixed esterification of PVA with MSA and TLA led to chemically crosslinked PVA-SNO films with a high swelling capacity capable of spontaneously releasing NO. Real time NO-release measurements revealed that the hydrogel layer reduces the initial NO burst from the PVA-SNO films. We demonstrate that the combination of PVA-SNO films with F127 hydrogel accelerates wound contraction, decreases wound gap and cellular density and accelerates the inflammatory phase of the lesion. These results were reflected in an increase in myofibroblastic differentiation and collagen type III expression in the cicatricial tissue. Therefore, PVA-SNO films combined with F127 hydrogel may represent a new approach for active wound dressings capable of accelerating wound healing.
PDF
