scholarly journals Fluorophore spectroscopy in aqueous glycerol solution: the interactions of glycerol with the fluorophore

Author(s):  
Haim Feldman ◽  
Mark A. Iron ◽  
Dror Fixler ◽  
Sergei Moshkov ◽  
Naomi Zurgil ◽  
...  
Keyword(s):  
Author(s):  
Russell N. A. Cecil ◽  
H. Clarke Anderson

Unfixed proximal tibial epiphyseal growth plates were studied by freeze-etch to confirm the presence of extracellular calcifying matrix vesicles and to determine the substructure of matrix vesicle membranes as compared to plasma and other membranes of intact chondrocytes. Growth plates from 6-10 week old Sprague-Dawley rats were cut into 1x3 mm blocks whose long dimension was oriented either perpendicular or parallel to the long axis of the tibia. Some blocks were fixed at pH 7. 0 in 0. 2M cacodylate - buffered 2. 5% glutaraldehyde for 1 hour at 4ÅC. The blocks were immersed in 30% glycerol solution at 4ÅC for 1 hour, frozen in liquid nitrogen, and then fractured, etched for 2 minutes, and coated with platinum, carbon and 0. 2% Formvar solution. The replicas were cleaned with chromic acid, floated onto Formvar coated grids, and examined with a Phillips EM 300 electron microscope.Fixed and unfixed specimens appeared similar in ultrastructure. Chondrocytes, matrix, and matrix vesicles were identified. In specimens fractured parallel to the long axis of the tibia, the reserve, proliferative, hypertrophic, and calcifying zones could be discerned as described by light and electron microscopy.


Fermentation ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 14
Author(s):  
Nelson Mota de Carvalho ◽  
Diana Luazi Oliveira ◽  
Mayra Anton Dib Saleh ◽  
Manuela Pintado ◽  
Ana Raquel Madureira

The use of fecal inoculums for in vitro fermentation models requires a viable gut microbiota, capable of fermenting the unabsorbed nutrients. Fresh samples from human donors are used; however, the availability of fresh fecal inoculum and its inherent variability is often a problem. This study aimed to optimize a method of preserving pooled human fecal samples for in vitro fermentation studies. Different conditions and times of storage at −20 °C were tested. In vitro fermentation experiments were carried out for both fresh and frozen inoculums, and the metabolic profile compared. In comparison with the fresh, the inoculum frozen in a PBS and 30% glycerol solution, had a significantly lower (p < 0.05) bacterial count (<1 log CFU/mL). However, no significant differences (p < 0.05) were found between the metabolic profiles after 48 h. Hence, a PBS and 30% glycerol solution can be used to maintain the gut microbiota viability during storage at −20 °C for at least 3 months, without interfering with the normal course of colonic fermentation.


Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1170
Author(s):  
Yuan Zhu ◽  
Benkun Qi ◽  
Xinquan Liang ◽  
Jianquan Luo ◽  
Yinhua Wan

Herein, corn stover (CS) was pretreated by less corrosive lewis acid FeCl3 acidified solutions of neat and aqueous deep eutectic solvent (DES), aqueous ChCl and glycerol at 120 °C for 4 h with single FeCl3 pretreatment as control. It was unexpected that acidified solutions of both ChCl and glycerol were found to be more efficient at removing lignin and xylan, leading to higher enzymatic digestibility of pretreated CS than acidified DES. Comparatively, acidified ChCl solution exhibited better pretreatment performance than acidified glycerol solution. In addition, 20 wt% water in DES dramatically reduced the capability of DES for delignification and xylan removal and subsequent enzymatic cellulose saccharification of pretreated CS. Correlation analysis showed that enzymatic saccharification of pretreated CS was highly correlated to delignification and cellulose crystallinity, but lowly correlated to xylan removal. Recyclability experiments of different acidified pretreatment solutions showed progressive decrease in the pretreatment performance with increasing recycling runs. After four cycles, the smallest decrease in enzymatic cellulose conversion (22.07%) was observed from acidified neat DES pretreatment, while the largest decrease (43.80%) was from acidified ChCl pretreatment. Those findings would provide useful information for biomass processing with ChCl, glycerol and ChCl-glycerol DES.


2021 ◽  
pp. 1-11
Author(s):  
Jéssica Tereza Guedes de Oliveira Moraes ◽  
Maíra Maftoum Costa ◽  
Paula Cristina Santos Alves ◽  
Luciana Barros Sant’Anna

The human amniotic membrane (AM) is emerging as an interesting biomaterial for regenerative medicine due to its biological and mechanical proprieties. The beneficial effects of the AM are probably related to its bioactive factors produced by local cells and stored in the stromal matrix. However, the search for a preservation method capable of preserving AM properties remains a challenge. The aim of this study was to evaluate important features of 2 anatomical regions of the human AM (reflected and placental amnion) after different preservation methods. For this purpose, human placentas were harvested and processed for AM isolation and storage at 2 different conditions: room temperature for 18 h in DMEM (fresh AM) and −80°C in DMEM/glycerol solution for 30 days (cryopreserved AM). After the storage period, the structural integrity of the membrane was assessed by histological and Picrosirius polarization analysis, cellular viability analysis was performed using the MTT assay, and the soluble proteins were quantified with the Qubit Protein Assay Kit. Both preservation protocols reduced the cell viability, mainly in the placental amnion region of the AM, but preserved the morphology of epithelial and stromal layers, as well as the organization and distribution of collagen fibers. There was a reduction in soluble proteins only in fresh AM. Importantly, the cryopreserved AM group presented the same concentration as the control group. In conclusion, the cryopreservation using DMEM/glycerol was ideal for preserving the structural integrity and soluble protein content, indicating the feasibility of this method in preserving AM for its use in regenerative medicine.


2021 ◽  
Vol 7 (5) ◽  
pp. 01-09
Author(s):  
Ravi Shrivastava

Introduction: Allergic rhinitis (AR) in children is a common chronic pathology with a strong impact on patient quality of life. The main physiopathology affects the nasal cavity as a multi-factorial disease involving nasal mucosa damage, nasal inflammation with high concentrations of histamine, pro-inflammatory cytokines such as histamine, TNF-α, IL-4, IL-5, IL-6, IL-10, IL-13, and IgE antibodies on the nasal mucosa. Systemic entry of these proteins through damaged nasal mucosa maintains continued inflammatory and allergen cascades. Therefore, an ideal treatment should be multitarget in order to stop allergen exposure, inflammation, and nasal mucosa barrier degradation, but such treatments are nearly impossible to conceive. We envisaged an osmotic and protective nasal barrier film, not only capable of protecting the nasal mucosa from allergen exposure but also of trapping and neutralizing selected cytokines and cleaning the nasal surface continuously without using any harmful substance for children. Materials and Methods: We associated highly osmotic glycerol solution with specific plant polymers to conceive an osmotic but stable film. As plant polymers (tannins) can bind with selective proteins, a range of glycerol binding non-cytotoxic polymers were screened using the sandwich ELISA method to select those having binding affinity for allergen induced nasal proinflammatory cytokines. After verifying cytotoxicity and irritant potential, a 15-day observational clinical study was performed with approval from the ethics committee on 30 children aged between 4-13, suffering from allergic rhinitis. The test product (TP) was supplied in 15-ml nasal sprays and applied 2-3 times per day for a period of 15 days. Saline solution served as control (CP). The scores of nasal and ocular symptoms, effect on quality of life, eosinophil count in nasal smears, and need for antihistamine treatment was evaluated at the start, at 30 minutes and on days 2, 3 and 15 of treatment. Results: A few specific polymers were able to bind with selected cytokines and histamine at adequate filmogen concentrations. The osmotic film was stable, non-irritant and was able to clean the nasal mucosa continuously for 4-6h after each application. Clinical observations of Total Nasal Symptom Score (TNSS) grouping the scores of nasal congestion, runny nose, sneezing, and itching, revealed a strong decrease right after the 1st treatment in both groups but the reduction was much stronger and faster with the TP. The mean TNSS score reduction was 44.74% in CP vs 83.53% in the TP group after 7 days of treatment (p<0.001). Total Ocular Symptom Score (TOSS) was decreased by 21.13% and 51.41% in CP v/s 35.12 and 99.59% in TP group on days 2 and 7, respectively. Nasal smear eosinophil count was equally strongly reduced in the TP v/s CP group. No treatment-related side effects were recorded in any of the groups. Conclusion: Protecting the nasal mucosa against allergens, neutralizing inflammatory cytokines, and keeping the nasal surface clean with an osmotic polymeric film, constitute a major breakthrough for the treatment of allergic rhinitis in children. This simple but scientific and logical approach should avoid exposing children to chemicals and to their long-term side effects.


Author(s):  
Fengjuan Ge ◽  
Jie Zhu ◽  
Yan Xu ◽  
Jing Li ◽  
Xueyang Zhang

BiOBr photocatalysts were prepared by changing the solvent and synthesis method. SEM, XRD and BET characterization shows that the sample prepared in high-viscosity solution by precipitation method has tremella-like microstructure, with smaller size and higher surface area. Among them, the BiOBr prepared in glycerol solution (GR-P) has the highest surface area of 113.8 m2⋅[Formula: see text]. XRD also indicates that the GR-P has much more exposed (110) facets than other samples. The Rhodamine B degradation tests show that the GR-P has the best activity on both deethylation and aromatic ring destruction steps, indicating that the exposed (110) facets promote the degradation process.


Fluids ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 75 ◽  
Author(s):  
Aikaterini Mouza ◽  
Olga Skordia ◽  
Ioannis Tzouganatos ◽  
Spiros Paras

The aim of this study was to provide scientists with a straightforward correlation that can be applied to the prediction of the Fanning friction factor and consequently the pressure drop that arises during blood flow in small-caliber vessels. Due to the small diameter of the conduit, the Reynolds numbers are low and thus the flow is laminar. This study has been conducted using Computational Fluid Dynamics (CFD) simulations validated with relevant experimental data, acquired using an appropriate experimental setup. The experiments relate to the pressure drop measurement during the flow of a blood analogue that follows the Casson model, i.e., an aqueous Glycerol solution that contains a small amount of Xanthan gum and exhibits similar behavior to blood, in a smooth, stainless steel microtube (L = 50 mm and D = 400 μm). The interpretation of the resulting numerical data led to the proposal of a simplified model that incorporates the effect of the blood flow rate, the hematocrit value (35–55%) and the vessel diameter (300–1800 μm) and predicts, with better than ±10% accuracy, the Fanning friction factor and consequently the pressure drop during laminar blood flow in healthy small-caliber vessels.


2005 ◽  
Vol 47 (6) ◽  
pp. 347-350 ◽  
Author(s):  
Cláudio S. Ferreira

Thick smears of human feces can be made adequate for identification of helminth eggs by means of refractive index matching. Although this effect can be obtained by simply spreading a fleck of feces on a microscope slide, a glycerol solution has been routinely used to this end. Aiming at practicability, a new quantitative technique has been developed. To enhance both sharpness and contrast of the images, a sucrose solution (refractive index = 1.49) is used, which reduces the effect of light-scattering particulates. To each slide a template-measured (38.5 mm³) fecal sample is transferred. Thus, egg counts and sensitivity evaluations are easily made.


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