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685 result(s) for "Guatemala"
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Validation of an Analytical Method for the Simultaneous Determination of Hyaluronic Acid Concentration and Molecular Weight by Size-Exclusion Chromatography
The hyaluronic acid (HA) global market growth can be attributed to its use in medical, cosmetic, and pharmaceutical applications; thus, it is important to have validated, analytical methods to ensure confidence and security of its use (and to save time and resources). In this work, a size-exclusion chromatography method (HPLC-SEC) was validated to determine the concentration and molecular distribution of HA simultaneously. Analytical curves were developed for concentration and molecular weight in the ranges of 100–1000 mg/L and 0.011–2.200 MDa, respectively. The HPLC-SEC method showed repeatability and reproducibility greater than 98% and limits of detection and quantification of 12 and 42 mg/L, respectively, and was successfully applied to the analysis of HA from a bacterial culture, as well as cosmetic, and pharmaceutical products.
Characterization of Nuclear Pleomorphism and Tubules in Histopathological Images of Breast Cancer
Breast cancer (BC) diagnosis is made by a pathologist who analyzes a portion of the breast tissue under the microscope and performs a histological evaluation. This evaluation aims to determine the grade of cellular differentiation and the aggressiveness of the tumor by the Nottingham Grade Classification System (NGS). Nowadays, digital pathology is an innovative tool for pathologists in diagnosis and acquiring new learning. However, a recurring problem in health services is the excessive workload in all medical services. For this reason, it is required to develop computational tools that assist histological evaluation. This work proposes a methodology for the quantitative analysis of BC tissue that follows NGS. The proposed methodology is based on digital image processing techniques through which the BC tissue can be characterized automatically. Moreover, the proposed nuclei characterization was helpful for grade differentiation in carcinoma images of the BC tissue reaching an 0.84 accuracy. In addition, a metric was proposed to assess the likelihood of a structure in the tissue corresponding to a tubule by considering spatial and geometrical characteristics between lumina and its surrounding nuclei, reaching an accuracy of 0.83. Tests were performed from different databases and under various magnification and staining contrast conditions, showing that the methodology is reliable for histological breast tissue analysis.
Supercritical CO2-ethanol extraction of oil from green coffee beans: optimization conditions and bioactive compound identification
In this research, a supercritical CO2-ethanol extraction was optimized to obtain a green coffee oil rich in bioactive compounds. A face-centered central composite design was used to evaluate the effect of temperature (50–70 °C), extraction pressure (15.0–30.0 MPa), and cosolvent content (5–20%) on the extraction yield and total phenolic compound content of green coffee supercritical extract (GCSE). The experimental data were fitted to a second-order polynomial model. According to the statistical analyses, the lack of fit was not significant for either mathematical model. From the response surface plots, the extraction pressure and cosolvent content significantly impacted the extraction yield, while the total phenolic compound content was impacted by temperature and cosolvent content. The optimal conditions were a 20% cosolvent content, a pressure of 30 MPa, and a temperature of 62 °C, which predicted an extraction yield of 7.7% with a total phenol content of 5.4 mg gallic acid equivalent g GCSE−1. The bioactive compounds included 5-caffeoylquinic acid (11.53–17.91 mg g GCSE−1), caffeine (44.76–79.51 mg g GCSE−1), linoleic acid (41.47–41.58%), and palmitic acid (36.07–36.18%). Our results showed that GCSE has the outstanding chemical quality and antioxidant potential, suggesting that GCSE can be used as a functional ingredient.
Optimization of 5-CQA Extraction Conditions from Green Coffee By-Product (Coffea arabica) Using a Response-Surface Design and the Study of Its Extraction Kinetics
To take advantage of the residues generated in the production of products from green coffee and due to the special interest in the compounds contained in the bean, a by-product obtained after the extraction of the oil was studied. The physical characterization of the green-coffee-bean by-product was carried out. Subsequently, the extraction of compound 5-CQA was carried out via leaching using central composition design 24 and evaluating factors such as temperature, time, solid/solvent ratio, and ethanol percentage, and its yield was quantified using HPLC. In addition, the response-surface methodology was used to maximize the efficiency of 5-CQA extraction and to perform the kinetic study. Yields of 59 ± 2 mg of 5-CQA/g from the by-product were obtained, and by selecting the best leaching conditions, the kinetic study was performed at 45, 60, and 75 °C, increasing the yield to a total of 61.8 ± 3 mg of 5-CQA/g. By applying the kinetic model of mass transfer, a fit of R2 > 0.97 was obtained, with KLa values between 0.266 and 0.320 min−1. This study showed an approach to optimize the 5-CQA extraction conditions, resulting in a simple, fast, reproducible, accurate, and low-cost method.
Evaluation of mango residues to produce hyaluronic acid by Streptococcus zooepidemicus
Mango processing generates significant amounts of residues (35–65%) that may represent environmental problems owed to improper disposal. The use of mango byproducts as substrates to produce hyaluronic acid (HA) is an attractive alternative to reduce the cost of substrate. In this study, we evaluated the potential of hydrolyzates from mango peels and seeds to produce HA by Streptococcus equi. subsp. zooepidemicus. The physicochemical characterization of mango residues showed that the seeds contain a higher amount of holocellulose (cellulose and hemicellulose), which amounts 54.2% (w/w) whereas it only represents 15.5% (w/w) in the peels. Mango peels, however, are composed mainly of hot water-extractives (62% w/w, that include sucrose, fructose, glucose and organic acids). A higher concentration of monosaccharides (39.8 g/L) was obtained from the enzymatic hydrolysis (with Macerex) of peels as compared to seeds (24.8 g/L with Celuzyme). From mango peels, hydrolyzates were obtained 0.6 g/L HA, while 0.9 g/L HA were obtained with hydrolyzates from mango seeds. These results demonstrate that mango byproducts have the potential to be used for production of HA.
8612 Thyrotoxic Periodic Paralysis in Marine-Lenhart Syndrome
Abstract Disclosure: I.A. Guatemala Funes: None. A. Tasnim: None. Y. El-Soufi: None. T. Zahedi: None. F. Zhang: None. Introduction: Thyrotoxic periodic paralysis (TPP) is a form of periodic muscle weakness that can be present in any form of hyperthyroidism. Patients present with progressive muscle paralysis as a result of acute hypokalemia. It is commonly seen in the Asian population, males more than females. We report a rare case of an Afro-American patient with TPP who also has a suspected coexistence of Graves' disease and functioning thyroid nodule, known as Marine-Lenhart syndrome. Case Report: The patient is a 31-year-old African American man with no past medical history, who presented with progressive generalized weakness predominantly in the extremities with grade 1 muscle strength after a meal high in carbohydrates. CT head, CT angiogram head neck, and MRI spine were unremarkable. Labs revealed hypokalemia 1.8 mmol/L, suppressed TSH < 0.015 uIU/mL, elevated Free T4 2.36 ng/dL, T3 13.5 pg/mL, thyroid stimulating immunoglobulin (TSI) 2.43 IU/L, thyrotropin receptor autoantibodies (TRAb) 2.03 IU/L, and thyroid peroxidase antibodies (TPO) 323 IU/mL. Thyroid ultrasound showed a markedly heterogeneous thyroid gland with bilateral multiple solid nodules, which confirmed the coexistent nodular goiter in Graves' disease. His symptoms improved after receiving Methimazole and electrolytes replacement. However, patient did not take Methimazole after discharge due to abnormal liver function. Five months later, he was readmitted with the similar presentation of progressive weakness and unable to stand up. Labs revealed hypokalemia 2.3 mmol/L, TSH 0.000 uIU/mL, and elevated Free T4 2.41 ng/dL, which suggested TPP. His paralysis resolved with treatment and patient was discharged with a radioactive iodine (RAI) uptake test scheduled to define the diagnosis but he was lost to follow-up. Discussion: The underlying mechanism of TPP is not completely understood. The overstimulation of the NA+/K+ ATPase pumps due to a hyperadrenergic state and elevated insulin level has been described as one of the major reasons along with a decrease in the outward potassium channels. A high carbohydrate intake and demanding exercise are some of the factors that can trigger the episode. The mainstay of therapy for TPP is controlling the hyperthyroidism and potassium replacement which usually resolve the paralysis. Proper differential diagnosis of hyperthyroidism such as Marine-Lenhart syndrome will benefit patients to identify the optimum long-term therapy with thioamides, surgery, or RAI ablation. Presentation: 6/1/2024
Evaluation of the Use of a Coffee Industry By-Product in a Cereal-Based Extruded Food Product
The evaluation of by-products to be added to food products is complex, as the residues must be analyzed to demonstrate their potential use as safe foods, as well as to propose the appropriate process and product for recycling. Since coffee is a very popular beverage worldwide, the coffee industry is responsible for generating large amounts of by-products, which include the coffee silverskin (CS), the only by-product of the roasting process. In this work, its characterization and food safety were evaluated by chemical composition assays, microbiological determinations, aflatoxin measurements and acute toxicity tests. The results showed that CS is safe for use in food, in addition to providing dietary fiber, protein and bioactive compounds. An extruded cereal-based ready-to-eat food product was developed through an extreme vertices mixture design, producing an extruded food product being a source of protein and with a high fiber content. Up to 15% of CS was incorporated in the extruded product. This work contributes to the establishment of routes for the valorization of CS; nevertheless, further research is necessary to demonstrate the sustainability of this food industry by-product.
Innovation in a Continuous System of Distillation by Steam to Obtain Essential Oil from Persian Lime Juice (Citrus latifolia Tanaka)
The citrus industry is one of the most important economic areas within the global agricultural sector. Persian lime is commonly used to produce lime juice and essential oil, which are usually obtained by batch distillation. The aim of this work was to validate a patented continuous steam distillation process and to both physically and chemically characterize the volatile fractions of essential Persian lime oil. Prior to distillation, lime juice was obtained by pressing the lime fruit. Afterwards, the juice was subjected to a continuous steam distillation process by varying the ratio of distillate flow to feed flow (0.2, 0.4, and 0.6). The distillate oil fractions were characterized by measuring their density, optical rotation, and refractive index. Gas chromatography GC-FID was used to analyze the chemical compositions of the oil fractions. The process of continuous steam distillation presented high oil recovery efficiencies (up to 90%) and lower steam consumption compared to traditional batch process distillation since steam consumption ranged from 32 to 60% for different steam levels. Moreover, a reduction in process time was observed (from 8 to 4 h). The oil fractions obtained via continuous steam distillation differed significantly in their composition from the parent compounds and the fractions.
Effect of Operating Conditions and Fructans Size Distribution on Tight Ultrafiltration Process for Agave Fructans Fractionation: Optimization and Modeling
The objective of this work was to evaluate the effect of operating conditions and fructans size distribution on the tight Ultrafiltration process for agave fructans fractionation. A mathematical model of limiting mass flux transfer was used to represent the profile of concentrations over time at the outlet of a pilot scale ultrafiltration system. First, a Box-Behnken experimental design was performed for the optimization of the parameters that determine the operating conditions in their respective ranges: temperature, 30–60 °C; transmembrane pressure (TMP), 1–5 bar and feed concentration, 50–150 kg∙m−3, on the separation factor (SF) and permeate flux. Then, the validation of the model for different fructans size distribution was carried out. The results showed that for SF, the quadratic terms of temperature, TMP and feed concentration were the most significant factors. Statistical analysis revealed that the temperature-concentration interaction has a significant effect (p < 0.005) and that the optimal conditions were: 46.81 °C, 3.27 bar and 85.70 kg∙m−3. The optimized parameters were used to validate the hydrodynamic model; the adjustments conclude that the model, although simplified, is capable of correctly reproducing the experimental data of agave fructans fractionation by a tight ultrafiltration pilot unit. The fractionation process is favored at higher proportions of FOS:Fc in native agave fructans.
Production of Hydrogen with Ruminal Microbiota: Finding Culture Conditions for High Yields
Hydrogen is ideal for replacing fossil fuels because upon combustion it generates only water. Dark fermentation (DF) from lignocellulose might be a competitive process for hydrogen production at the industrial scale. However, lignocellulose must be pretreated to obtain fermentable sugars, which is costly and creates pollution. Microorganisms from bovine rumen efficiently degrade lignocellulose. Unfortunately, they have scarcely been explored for the production of hydrogen. Therefore, deeper studies on the culture conditions have to be undertaken to understand the behavior of microbial consortia from the rumen of bovines (MCRB) during hydrogen production. In this work, we evaluated the production of hydrogen by DF with MCRB by varying the incubation time, two culture media (MB and Rhodospirillaceae), headspace (40 and 80 mL), and thermal treatment. It was found that the production of hydrogen was maximum at 16 h MCRB incubation in MB. An amount of 80 mL headspace resulted in a threefold production of hydrogen as compared to 40 mL; the MCRB without heat treatment had a higher H2 yield. The production of hydrogen with 32 MCRB was highly variable, ranging between 21 and 696 mL. Our findings show a different perspective on the treatment of MCRB for the production of hydrogen and give insights on the impact of the culture conditions for increasing hydrogen production.