Anhydrous Glycerol Research Articles

Hydroxyproline Concentration and Associated Factors of Preserved Small Incision Lenticule Extraction-Derived Corneal Stromal Lenticules.

To evaluate changes of hydroxyproline concentration and its influencing factors of small incision lenticule extraction (SMILE)-derived corneal stromal lenticules with different preservation methods. A total of 390 corneal stromal lenticules of 195 patients were derived from SMILE surgeries. Thirty of the lenticules were classified as the fresh (control) group, and the rest were randomly and evenly divided and stored in anhydrous glycerol, silicone oil, Optisol, and cryopreservation for 1 day, 1 week, or 1 month. A hydroxyproline assay kit (ab222941, Abcam) was used to measure the hydroxyproline concentration in each preservation method. Concentrations of MMP-2, TIMP-2, TNFα, TGFβ2, and reactive oxygen species were also evaluated. In the anhydrous glycerol group, the concentration of hydroxyproline decreased within 1 week (fresh: 1 dΔ = 0.229, P < 0.001*; 1 d - 1 wΔ = 0.055, P < 0.001*) while that in the silicone oil group remained stable in 1 week (1 d - 1 wΔ = -0.005, P = 0.929) and decreased significantly in 1 m (1 m - 1 wΔ = -0.041, P = 0.003*). The sequence of hydroxyproline concentration in the Optisol group was 1 m > 1 day > 1 week. Hydroxyproline concentration in the cryopreservation group decreased within 1 m. Hydroxyproline concentration was highest in the Optisol group and lowest in the anhydrous glycerol group under the same preservation time. Hydroxyproline concentration was negatively correlated with MMP-2 (r = -0.16, P = 0.421) and TIMP-2 (r = -0.56, P = 0.002*) while MMP-2 and TNFα (r = 0.17, P = 0.242), TIMP-2 and TGFβ2 (r = 0.21, P = 0.207), and TNFα and reactive oxygen species (r = 0.52, P = 0.007*) were positively correlated. More collagen was retained in SMILE lenticules preserved in Optisol under the same preservation time. The mechanism of the changes of collagen in preserved SMILE-derived lenticules and oxidative stress requires additional investigation.

Study on the biological properties of SMILE-derived corneal stromal lenticules after long-term cryopreservation in nutrient capsules

PurposeTo investigate the long-term preservation effects of nutrient capsules on the physiological activity, collagen fiber structure and transmittance of corneal stromal lenticules derived from small incision lenticule extraction (SMILE). MethodsA new nutrient capsule was constructed for long-term preservation of SMILE-derived corneal stromal lenticules. The lenticules were randomly divided into 99% anhydrous glycerol, and hydrogel nutrient capsules. After preserving for 1 year at −80 °C, lenticules were compared with fresh lenticules. The optical transmittance, tissue morphology, ultrastructure, cells activity and immunogenicity of the lenticules was detected and compared between different groups. ResultsThe rate of apoptotic cells was significantly higher in the glycerol group compared with the nutrient capsule group (P < 0.0001). More viable cells were present in the lenticules after nutrient capsule preservation compared to the glycerol group (P = 0.0003). The mean transmittance of the lenticules in the glycerol group (50 ± 18%) was significantly lower (P = 0.0008) compared to the control group (75 ± 11%), and the lenticules transmittance of the nutrient capsule group (64 ± 15%) after long-term preservation was not significantly different (P = 0.23) compared to the control group. The structure of HE staining showed that the collagen fibers in the nutrient capsule group were arranged in parallel and neatly, and a few cavitation vesicles were visible inside the tissue. There was no significant difference in the number of lenticular collagen fibers in the nutritional capsule group compared to the fresh lenticule group (P = 0.06). HLA-DR, HLA-ABC, CD45, CD25 and CD69 expression was low in all groups of lenticules after preservation. ConclusionsNutrient capsules can preserve lenticules for a long time and maintain the transmission structure and cells activity of lenticules.

Determining the Molecular Weight of Polyelectrolytes Using the Rouse Scaling Theory for Salt-Free Semidilute Unentangled Solutions

Chain dynamics in the semidilute unentangled regime can be used to determine the molecular weight of polyelectrolytes based on the Rouse scaling model. Four methods enable determination of the number density of chains via measurements of correlation length (ξ) by small-angle X-ray scattering, specific viscosity (ηsp) and relaxation time (τ) by rheometry, and diffusion coefficient (D) by NMR. Five narrow dispersity cesium polystyrene sulfonate (CsPSS) solutions without salt are studied in water, anhydrous ethylene glycol, and anhydrous glycerol to test all methods. Combining viscosity and correlation length yields the weight-average molecular weight (Mw) from the Rouse model. Combining diffusion coefficient and correlation length in water provides number-average molecular weight (Mn) reliably for chains with N < 2000 repeat units. Glycerol slows relaxation dynamics, and the shear rate dependence of viscosity yields reliable τ for CsPSS with N > 100, which is governed by the product of z-average and z + 1 average molecular weight (MzMz+1) in the Rouse model. Terminal modulus G = (η – ηs)/τ via rheometry correlates with Mw/MzMz+1.

Comparison of Cryosurgery and Peripheral Glycerol Injection in Treatment of Trigeminal Neuralgia

Background: Trigeminal neuralgia (TN) is a unique debilitating ailment due to its typical symptoms and wide array of surgical treatment modalities available for TN and it is important to select the most appropriate surgical procedure. Aim: To compare the efficacy of peripheral glycerol injection and cryosurgery in the remission of pain in the treatment of trigeminal neuralgia. Methodology: A randomized controlled trial (RCT) study was started after taking ethical approval, total of 80 patients of both gender were included in this study at Department of Oral and Maxillofacial Surgery, Nishtar Institute of Dentistry Multan from July 2017-January 2018. Patients were divided in two equal groups randomly, group A was treated with peripheral glycerol injection and group B with cryosurgery. Patients were followed up for 3rd month to evaluate the efficacy. All results were entered and analyzed in SPSS 24 version. Outcome variables were presented as mean and SD and qualitative variables were presented as frequency/percentages. Probability value ≤0.05 was considered as significant. Results: The efficacy of cryosurgery was observed as (75%), while the efficacy of anhydrous glycerol was noted as (37.5%). This study results support the cryosurgery rather than peripheral glycerol injection in the treatment of trigeminal neuralgia as cryosurgery has higher efficacy and low recurrence rate in controlling pain than peripheral glycerol injection. Efficacy in both groups with age in 40-65 years (p=0.003) was significant. Efficacy in both groups with type of nerve in mental nerve (p=0.030) and inferior alveolar (p=0.039) were significant and infraorbital (p=0.197) and lingual nerve (p=0.386) were not significant. Conclusion: Our study results were supported to the cryosurgery rather than the injection of peripheral glycerol for treatment of trigeminal neuralgia. Keywords; Trigeminal Neuralgia, Peripheral Glycerol injection, Cryosurgery.

Comparison of the Effects of Temperature and Dehydration Mode on Glycerin-Based Approaches to SMILE-Derived Lenticule Preservation

The aim of this study was to explore the optimal method of small-incision lenticule extraction (SMILE)-derived lenticules, subjected to long-term preservation using glycerol, under a range of temperatures, and using an array of dehydration agents. In total, 108 myopic lenticules were collected from patients undergoing the SMILE procedure. Fresh lenticules served as a control group for this study, whereas all other lenticules were separated into 8 groups, which were preserved at 4 different temperatures (room temperature [RT], 4, -20, and -80°C) with or without silica gel in anhydrous glycerol. Evaluated parameters included thickness, transmittance, hematoxylin and eosin staining, transmission electron microscopy, and immunohistochemistry analyses. After a 3-month preservation period, lenticular thickness in these different groups was significantly increased, particularly for samples stored at RT. The mean percentage transmittance of lenticules stored at -80°C with or without silica gel was closest to that of fresh lenticules. Hematoxylin and eosin staining revealed sparsely arranged collagen fibers that were more scattered in preserved lenticules relative to fresh lenticules, particularly in RT samples. Transmission electron microscopy revealed that the fibril bundles densities in lenticules stored at RT were significantly less than those stored at other temperatures. Immunohistochemistry analyses revealed reductions in or loss of CD45 and human leukocyte antigens in all preserved lenticules relative to control samples. Of the tested approaches, the preservation of SMILE-derived lenticules over a 3-month period was optimal at -80°C with or without silica gel in anhydrous glycerol.

Risk Evaluation of Human Corneal Stromal Lenticules From SMILE for Reuse.

To investigate the pathogenicity and immunogenicity of human corneal stromal lenticules from small incision lenticule extraction (SMILE). Serological testing was completed prior to sample collection to rule out infectious diseases. Pathogens herpes simplex viruses (HSV) type 1 and type 2 were screened for by real-time fluorescent quantitative polymerase chain reaction, and bacteria, fungi, and Acanthamoeba from 128 lenticules of 64 patients were cultured. A total of 132 lenticules from 93 patients were randomly assigned to the fresh group, -78 °C anhydrous glycerol preservation group (glycerol group), and 0.1% sodium dodecyl sulfate decellularization group (SDS group) in pairs and detected by immunohistochemistry, Western blot, transmission electron microscopy, transmittance, and nanoindentation. The fresh lenticules were all negative for HSV-1, HSV-2, bacteria, fungi, and Acanthamoeba. HLA-I A/B/C and HLA-II DR antigens were all expressed in fresh lenticules but were clearly reduced after preservation at -78 °C in anhydrous glycerol or decellularization in 0.1% SDS. The collagen fibers of the lenticules in the fresh group were regularly arranged, and the keratocytes were intact. The fibers in the glycerol group were regularly arranged, and the integrity of keratocytes was destroyed. The fibers in the SDS group were disordered and had no cellular structure. The transmittance and Young's modulus were highest in the fresh group, lower in the glycerol group, and lowest in the SDS group. Risk of infection is low, but risk of rejection exists on the reuse of fresh human corneal stromal lenticules from SMILE. Anhydrous glycerol preservation at -78 °C is an ideal method for reducing antigens without damaging the structure and function of lenticules. [J Refract Surg. 2021;37(1):32-40.].

Optical transmittance and ultrastructure of SMILE-derived lenticules subjected to three different preservative methods

PurposeTo investigate the optical transmittance and ultrastructure of small incision lenticule extraction (SMILE)-derived lenticules preserved via three different methods. MethodsA total of 90 lenticules obtained from myopic patients undergoing SMILE surgery were divided into control and experimental groups. Fresh lenticules served as the control. The preserved lenticules of the experimental group were randomly divided into three subgroups according to different storage conditions: anhydrous glycerol, silicone oil and allochroic silica gel groups. Optical transmittance was evaluated, histological changes were analysed by haematoxylin eosin (HE) staining, and collagen fibril densities and necrotic response were assessed via transmission electron microscopy (TEM) at 48 h, 14 days and 4 weeks. ResultsAfter storage for 4 weeks, the mean percentage transmittance values in glycerol and silicone oil groups significantly decreased (P = 0.034 and P = 0.042, respectively), but the lenticules preserved in silica gel remained unchanged when compared with the control lenticules. In all the groups, HE staining results showed a regular arrangement of collagen fibers with a few keratocytes and several cavitation bubbles. TEM revealed that the fibril densities in the glycerol group (273.70 ± 31.42/μm2) after 4 weeks were significant less than those in the other two groups (silicone oil, 335.20 ± 33.09/μm2; silica gel, 371.80 ± 37.60/μm2) and control group (340 ± 33.61/μm2) (all P < 0.001). In each group, a few necrotic and apoptotic keratocytes were observed. ConclusionsAll the three agents, namely glycerol, silicone oil and silica gel, could be used for lenticule preservation. Silica gel facilitates better maintenance of optical transmittance than the other two agents.

Three species of genus Basiria (Nematoda: Tylenchidae) from fruit orchards in Khuzestan province, Southwestern Iran

The soil samples were collected from pomegranate, fig, grapevine, berry, date palm, lemon and orange to identify the nematodes of the genus Basiria in the fruit orchards of Khuzestan province (Southwestern Iran). After extraction, fixation and transferring to anhydrous glycerol, the nematodes were mounted on microscopic slides. Nematodes identified at the species level, based on morphological and morphometrical characters, using a light microscope equipped with a drawing tube and valid keys. In this study, three species were identified, namely: B. berylla, B. gracilis and B. graminophila. Morphometrics and light micrography were provided for the studied species. This is a new record of B. berylla and B. gracilis for the nematode fauna in the Khuzestan province. According to available references, this is the first report of B. berylla from berry and fig and B. gracilis from grapevine in Iran.

Glycerolysis of Poly(lactic acid) as a Way to Extend the "Life Cycle" of This Material.

The article concerns the use of glycerolysis reaction as an alternative method of processing post-production and post-consumer waste from poly(lactic acid) (PLA). Management of waste is a very important issue from an environmental protection and economic point of view. Extending the “life cycle” of PLA is extremely important because it allows to make the most of this material. It also limits economic losses resulting from its disposal in the biodegradation process at the same time. This paper presents a method of glycerolysis of poly(lactic acid) waste using various amounts of anhydrous glycerol (mass ratio from 0.3 to 0.5 parts by weight of glycerol per 1.0 part by weight of PLA). This process was also carried out for pure, unmodified PLA Ingeo® (from NatureWorks) to compare the obtained results. The six liquid oligomeric polyhydric alcohols were obtained as a result of the synthesis. Then, they were subjected to physicochemical tests such as determination of color, smell, density, viscosity, and pH. In addition, the obtained raw materials were subjected to analytical tests such as determination of the hydroxyl value, acid value, water content, and elemental composition. The average molecular weights and dispersity were also tested by gel permeation chromatography (GPC). The assumed chemical structure of the obtained compounds was confirmed by spectroscopic methods such as FTIR, 1H NMR, 13C NMR. Glycerolysis products were also subjected to differential scanning calorimetry (DSC) to determine thermal parameters. The obtained research results have allowed the precise characterization of newly obtained products and determination of their suitability, e.g., for the synthesis of polyurethane (PUR) materials.

Multiple laser pulses in conjunction with an optical clearing agent to improve the curative effect of cutaneous vascular lesions.

Port-wine stains (PWSs) usually respond poorly to pulsed dye laser treatment because of the shallow penetration and light absorption of melanin in the epidermis. Multiple laser pulses (MLPs) Nd:YAG laser in conjunction with an optical clearing agent can help to reduce the total laser energy required for blood coagulation. The quantitative optical clearing effect (OCE) of glycerol was investigated by using a tissue-like phantom. Thereafter, an in vitro capillary tube experimental system and an in vivo hamster dorsal skin chamber experiment for the laser treatment of PWSs were established to visually obtain the quantitative relationship between the OCE and the blood coagulation properties under the irradiation of 1064nm MLPs. Diffuse reflection coefficient decreases by 36.69% and transmission coefficient increases by 38.73% at 1064nm, after applying 0.5mL anhydrous glycerol for 10min on the surface of the tissue-like phantom. The number of laser pulses required for blood coagulation decreases by 25% after the application of 0.5mL anhydrous glycerol for 4min, thrombosis appears after 10min, and the 0.0854 clotting area completely blocks the capillary tubes in 6 pulses. For 10min, the incident energy can be reduced by 35.09 and 29.82%. When the 0.3-mm vessel's buried depths are 1 and 0.5mm, the pulse number can be reduced from 11 to 8 and from 6 to 4, respectively. Adding anhydrous glycerol directly on the hamster dorsal skin is an effective way to reduce the number of laser pulses from 4∼5 to 2∼3 for similar capillary tube diameter. Therefore, the MLPs of 1064nm Nd:YAG demonstrates a substantial curative effect for large capillary tubes. In conjunction with glycerol, this approach may treat deeply buried cutaneous capillary tubes and prevent the unwanted thermal damage of normal dermal tissue.

Hydrogen Treated Niobium Oxide Nanotube Arrays for Photoelectrochemical Water Oxidation

Self-aligned Nb2O5 nanotube (NT) arrays are grown by facile electrochemical anodization at 180°C with an applied bias of 10 V for 10 min in anhydrous glycerol electrolyte. Amorphous Nb2O5 NT arrays can be transformed into pseudo-hexagonal Nb2O5 NT arrays by annealing at 440°C for 20 min in ambient air. Hydrogen treatment of this film was conducted at 440°C for 20 min with flowing 4% H2/96% Ar mixed gas. Hydrogen treatment causes no modification of crystalline properties and hydrogen-treated Nb2O5 (denoted as H2-Nb2O5) NT arrays exhibit no apparent change in the optical bandgap, indicating negligible visible light absorbance. Only small changes in structural properties, such as pore diameter, wall thickness, and chemical state, are observed in the surface region of H2-Nb2O5 NT arrays. However, H2-Nb2O5 NT arrays exhibit a significant increase in electron concentration by the formation of oxygen vacancies, leading to significantly enhanced electronic conductivity. As a result, charge recombination reactions in the interfacial region between H2-Nb2O5 NT arrays and electrolyte are efficiently hindered, resulting in remarkably enhanced photocurrent density in the photoelectrochemical cell. The air-Nb2O5 NT arrays exhibit a photocurrent density of only 0.11 mA/cm2 at 1.0 VNHE, while H2-Nb2O5 NT arrays show a significantly increased photocurrent density up to 0.69 mA/cm2 at 1.0 VNHE, a more than six-fold improvement in photoelectrochemical performance.

Long-term preservation of donor corneas in glycerol for keratoplasty: exploring new protocols

AimTo evaluate the role of temperature and adjunctive dehydration in better long-term preservation of human corneas when preserved and stored in glycerol.MethodsDifferent preservation temperatures and effects of adding silica gel...

Biomass Fractionation after Denaturing Cell Walls by Glycerol Thermal Processing

Denaturing biopolymers allows the transformation of highly organized natural structures into industrially relevant materials such as extruded starch or gelatin. This approach was used to fractionate wood into its biopolymer constituents by treating wood particles in polymer processing equipment at high temperatures in the presence of anhydrous glycerol. Nine severities were studied to assess the impact of time and temperature during processing. After processing, the biomass was stripped of its lignin and xylan by subsequent extractions without addition of added catalysts, leaving a relatively pure cellulose fraction, 84% glucan, as found in chemical pulps. Additionally, 41% of the lignin and 68% of the xylan was recovered in a dry powdered form. The hemicellulose side-chain carbohydrates such as arabinose and galactose were water extracted, while the majority of the mannan remained with the cellulose fiber. High temperature processing for short times in a benign solvent provides significant disruption of the cell wall, while anhydrous glycerol prevents significant degradation of the majority of the biopolymers into oligomers.

Reported some new species of plant parasitic nematodes from rhizosphere of tea plantation in Iran

Tea (Camellia sinensis) is one of the most important produce in Guilan province that most feild is allocated to this produce after rice in this province. In order to identify the plant parasitic nematodes of Tea plantation, 340 samples of soil around the roots of Tea were collected from different parts of the Tea plantation in provinces of Guilan and Mazandaran, during the summer and fall of 2011. After extraction, killing, fixation and transferring to anhydrous glycerol, the nematodes were mounted on permnanent microscopic slides and nematodes species identified by using light microscope, equipped with digital camera, based on morphological and morphometric characters using valid keys. In this study 22 species belonging 12 genera of nematodes infraorder Tylenchomorpha were identified, that before just 6 Species are reported from rhizosphere of Tea in Iran. others species are reported from rhizosphere of Tea in Iran from first reported.

Catalytic Etherification of Glycerol to Diglycerol Over Heterogeneous Calcium-Based Mixed-Oxide Catalyst: Reusability and Stability

The activities of different heterogeneous alkaline-earth metal oxide catalysts and mixed-metal oxide catalysts were investigated. Glycerol etherification was carried out at 250°C in a three-necked glass reactor vessel at atmospheric pressure. In a typical experiment, 50 g of anhydrous glycerol was loaded into the reactor. Then, 2 wt.% of catalyst was added to the reactor. The reactor was then heated to the appropriate reaction temperature in nitrogen atmosphere under continuous stirring. The heterogeneous CaO catalyst showed the highest catalytic conversion (72%) compared with other alkaline-earth metal oxides, with a diglycerol yield of 19%. The highest glycerol conversion of 96% and diglycerol yield of 52% were observed for the mixed-metal oxide catalyst (Ca1.6Al0.4La0.6O3). Reusability and stability of this catalyst were tested. The ICP-AES analysis was performed to confirm the leaching of the metal species in the liquid phase of the reaction mixture.

Microscale study of particle agglomeration in oil-based food suspensions: The effect of binding liquid

In highly concentrated oil or fat-based suspensions, the addition of a secondary immiscible liquid binder results in the agglomeration of particles and formation of a spanning filling network. This network gives rise to a transition in the flow behavior of suspensions which can, in turn, be used to create tailored food products.This agglomeration of particles is related to the formation of liquid bridges. The present work investigates this agglomeration process on a microscale. The effect of two binding liquids with different properties (viscosity, interfacial tension and wetting characteristics) on the adhesion of a particle and a flat surface inside oil medium is investigated. Forces due to water and anhydrous glycerol bridges between a spherical glass particle and a flat glass surface inside purified high oleic sunflower oil were measured with an atomic force microscope (AFM), using the colloidal probe technique. Dispersions of droplets of the secondary liquid (water, glycerol) in the continuous phase (oil) were prepared so that bridges between the particles and the glass surface could be created and force curves measured.The measured forces were dominated by capillary attraction when a liquid of high interfacial tension and low viscosity such as water formed the liquid bridges. When a highly viscous liquid formed the bridge (glycerol), a dynamic viscous interaction contributed to the adhesion leading to a higher force, which was less dependent on the volume of the bridge.

Study on reflection of human skin with liquid paraffin as the penetration enhancer by spectroscopy

Optical clearing agents can improve tissue optical transmittance by reducing the diffuse reflection. The reflection on in vivo human skin before and after applying anhydrous glycerol and 30 to 50% liquid paraffin glycerol mixed solution are investigated in this paper. From their visible and near-infrared reflection spectroscopy, all of their diffuse reflections are reduced after applying the agents. It is found that the three mixed solutions show stronger effect than that of anhydrous glycerol. These results further prove liquid paraffin can enhance the percutaneous penetration of glycerol and take synergistically optical clearing effect with glycerol over visible and near-infrared wave bands.

Preparation and study of vitamin A palmitate microemulsion drug delivery system and investigation of co-surfactant effect

Abstract The oral route is the main route of drug delivery in many diseases. A major problem in oral oil-soluble drug administration is poor aqueous solubility. One way to deliver oil-soluble drugs is to incorporate the drug into an inert vehicle, such as microemulsions. The purpose of this research was to develop the oil-in-water (o/w) microemulsion areas of pseudo-ternary phase diagrams for a drug delivery system. Our systems consist of sunflower oil + surfactant (Tween 80) + vitamin A palmitate + different co-surfactants + water. Vitamin A palmitate is an oil-soluble drug with poor aqueous solubility. Our goal is to increase its aqueous solubility. The effects of different co-surfactants on the o/w microemulsion region were investigated. The co-surfactants studied were anhydrous glycerol, sucrose, ethanol, and 1-propranol. A titration technique was employed for the preparation of the samples. The phases were identified by visual inspection and polarized microscopy. Samples of the microemulsion area were separated, and pseudo-ternary phase diagram was plotted for them. The system sunflower oil + Tween 80 + sucrose + water+ model drug showed the largest o/w microemulsion region. Consequently, sucrose was selected as the best co-surfactant. Finally, some samples of this system were selected for particle size measurement and stability testing. Results showed that more than 90% of the samples in different temperatures (4°C, 45°C, and room temperature) are stable.

Enlargement of Nanoemulsion Region in Pseudo‐ternary Mixing Diagrams for a Drug Delivery System

AbstractThe purpose of this research was to develop the pseudo‐ternary mixing diagrams for a potential drug delivery system consisting of vitamin E (potential drug) + soybean oil + surfactant + co‐surfactant (anhydrous glycerol) + water. The potential drug (vitamin E) was loaded in the oil phase. The effects of different surfactants (pure and mixed) on the mixing diagrams, especially on the nanoemulsion region, were investigated. The influence of the drug loading level on the mixing diagrams was also determined. The surfactants studied were polyethoxylated (20) sorbitan monolaurate, polyethoxylated (20) sorbitan monooleate, polyethoxylated (35) castor oil and their mixtures. The size (area) of the nanoemulsion region of the mixing diagrams was found to be dependent on the type of surfactant used and the loading level of the drug (vitamin E).

Transition moment directions and selected spectroscopic properties of Ivabradine

Based on the Kawski–Gryczynski method the value of angle β=38° between absorption and fluorescence transition moments of Ivabradine was determined. Such a high value of β is responsible for low emission anisotropy of Ivabradine in a rigid polyvinyl alcohol matrix and in anhydrous glycerol despite the elongated shape of the fluorophore. Selected steady-state and time-resolved spectroscopic results support the analysis.