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1.
Int J Mol Sci ; 24(23)2023 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-38069104

RESUMEN

CagY is the largest and most complex protein from Helicobacter pylori's (Hp) type IV secretion system (T4SS), playing a critical role in the modulation of gastric inflammation and risk for gastric cancer. CagY spans from the inner to the outer membrane, forming a channel through which Hp molecules are injected into human gastric cells. Yet, a tridimensional structure has been reported for only short segments of the protein. This intricate protein was modeled using different approaches, including homology modeling, ab initio, and deep learning techniques. The challengingly long middle repeat region (MRR) was modeled using deep learning and optimized using equilibrium molecular dynamics. The previously modeled segments were assembled into a 1595 aa chain and a 14-chain CagY multimer structure was assembled by structural alignment. The final structure correlated with published structures and allowed to show how the multimer may form the T4SS channel through which CagA and other molecules are translocated to gastric cells. The model confirmed that MRR, the most polymorphic and complex region of CagY, presents numerous cysteine residues forming disulfide bonds that stabilize the protein and suggest this domain may function as a contractile region playing an essential role in the modulating activity of CagY on tissue inflammation.


Asunto(s)
Gastritis , Infecciones por Helicobacter , Helicobacter pylori , Humanos , Proteínas Bacterianas/metabolismo , Helicobacter pylori/metabolismo , Antígenos Bacterianos/metabolismo , Inflamación
2.
Molecules ; 28(10)2023 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-37241822

RESUMEN

Phytochemicals are natural compounds found in plants that have potential health benefits such as antioxidants, anti-inflammatory and anti-cancer properties, and immune reinforcement. Polygonum cuspidatum Sieb. et Zucc. is a source rich in resveratrol, traditionally consumed as an infusion. In this study, P. cuspidatum root extraction conditions were optimized to increase antioxidant capacity (DPPH, ABTS+), extraction yield, resveratrol concentration, and total polyphenolic compounds (TPC) via ultrasonic-assisted extraction using a Box-Behnken design (BBD). The biological activities of the optimized extract and the infusion were compared. The optimized extract was obtained using a solvent/root powder ratio of 4, 60% ethanol concentration, and 60% ultrasonic power. The optimized extract showed higher biological activities than the infusion. The optimized extract contained 16.6 mg mL-1 resveratrol, high antioxidant activities (135.1 µg TE mL-1 for DPPH, and 230.4 µg TE mL-1 for ABTS+), TPC (33.2 mg GAE mL-1), and extraction yield of 12.4%. The EC50 value (effective concentration 50) of the optimized extract was 0.194 µg mL-1, which revealed high cytotoxic activity against the Caco-2 cell line. The optimized extract could be used to develop functional beverages with high antioxidant capacity, antioxidants for edible oils, functional foods, and cosmetics.


Asunto(s)
Fallopia japonica , Ultrasonido , Humanos , Resveratrol/farmacología , Antioxidantes/farmacología , Fallopia japonica/química , Células CACO-2 , Extractos Vegetales/farmacología , Extractos Vegetales/química , Alimentos Funcionales
3.
Molecules ; 27(15)2022 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-35956854

RESUMEN

This research developed model foods of gelatine-based gels, where carbohydrates from Agave tequilana Weber var. Azul (agave syrups or/and agave fructans) were incorporated into gel formulations as healthy sucrose and glucose substitutes. The sugars (sucrose and glucose) were substituted by agave carbohydrates (agave syrups and agave fructans), obtaining the subsequent gel formulations: 100% agave syrup (F2 gel), 100% agave fructan (F3 gel), and 50% agave syrup−50% agave fructan (F4 gel). The unsubstituted gel formulation was used as a control (F1 gel). The prebiotic activities, physical properties, thermal stability (HP-TLC), and texture of gelatine-based gels were evaluated. The gel formulations showed translucent appearances with approximately 36 g/100 g of water and water activities values between 0.823 and 0.929. The HP-TLC analysis validated that agave fructans did not hydrolyse during the thermal process of gels production. Gels produced with agave syrup and agave fructan (F2-F4 gels) provided higher hardness, gumminess, and springiness values (p < 0.05) than those produced with glucose and sucrose (F1 gel). Gelatine-based gel formulations displayed prebiotic activities correlated to the ability of Lactobacillus plantarum, Lactobacillus paracasei, and Lactobacillus rhamnosus to use agave carbohydrates as carbon sources. Based on the prebiotic effect and physical and textural properties, the F2 and F4 gel formulations displayed the best techno-functional properties to produce gel soft candies.


Asunto(s)
Agave , Fructanos/análisis , Gelatina , Geles , Glucosa , Lactobacillus , Prebióticos/análisis , Sacarosa , Agua
4.
Drug Dev Res ; 81(3): 350-355, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-31777976

RESUMEN

Acylthiosemicarbazides 8a-n were designed by structural modification of lead Compound 7. The syntheses of 8a-n involve a five-step procedure starting from carboxylic acids. Compounds 8a-n were tested against three Mycobacterium tuberculosis strains to measure their inhibitory antituberculosis activities. These activities could be explained according to the presence or absence of the chlorine substituent in the aromatic ring of the amide joined to the thiosemicarbazide core. Thiosemicarbazide derivative 8n is a candidate for the development of novel antitubercular agents. Ongoing studies are focused on exploring the mechanism by which these compounds inhibit M. tuberculosis cell growth.


Asunto(s)
Antituberculosos/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Semicarbacidas/farmacología , Animales , Antituberculosos/síntesis química , Antituberculosos/química , Chlorocebus aethiops , Semicarbacidas/síntesis química , Semicarbacidas/química , Relación Estructura-Actividad , Células Vero
5.
BMC Infect Dis ; 19(1): 1068, 2019 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-31856740

RESUMEN

BACKGROUND: Approximately 50% of cases of penile carcinoma (PeCa), a rare neoplasm worldwide, are associated with human papillomavirus (HPV). However, the detection of HPV-DNA is not sufficient to consider it the etiological factor in the development of this type of cancer. Currently, the overexpression of P16INK4A is used as a surrogate biomarker of HPV carcinogenesis. Information on PeCa in Mexico is scarce, particularly regarding cases related to HPV and genotype frequency. OBJECTIVE: To evaluate the presence of HPV, its genotypes, and the presence of multiple genotypes, and the expression of P16INK4A, as well as its clinical and histopathological parameters. METHODS: For HPV-DNA detection and P16INK4A expression, we used the INNO-LiPA® test and immunohistochemistry, respectively. RESULTS: Sixty cases of PeCa were evaluated, of which 75% were HPV-non-related histological variants. We found that 58.9% (33/56) of PeCa cases were HPV-DNA positive, while 30.9% of the cases evaluated (17/55) were positive for P16INK4A. HPV16 was the main genotype in 42.9% of the cases, followed by HPV52 in 7.1% and HPV18 in 5.4%. Within the HPV-positive cases, 27.3% had multiple genotypes. All HPV-positive patients under the age of 45 years were positive only for HPV16. CONCLUSIONS: HPV16 was the most commonly detected genotype in PeCa. HPV 31, 35 and 39 were infrequent; however, they were related to a single infection and P16INK4A overexpression; thus, they seem to be relevant in PeCa carcinogenesis. Our results suggest that P16INK4A overexpression could be useful for the classification of HPV-related PeCa. The role of multiple HPV genotypes in the development and prognosis of PeCa is still not completely understood. Thus, it is necessary to define criteria to establish reliable ways to classify HPV-related PeCa that could lead to optimal therapeutic approaches.


Asunto(s)
Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/virología , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Papillomavirus Humano 16/genética , Infecciones por Papillomavirus/genética , Infecciones por Papillomavirus/virología , Neoplasias del Pene/genética , Neoplasias del Pene/virología , Adulto , Anciano , Anciano de 80 o más Años , Biomarcadores de Tumor/metabolismo , Carcinoma de Células Escamosas/clasificación , Genotipo , Humanos , Inmunohistoquímica , Masculino , México , Persona de Mediana Edad , Infecciones por Papillomavirus/clasificación , Neoplasias del Pene/clasificación , Pronóstico , Enfermedades Raras/genética , Enfermedades Raras/virología , Adulto Joven
6.
J Clin Rheumatol ; 25(5): 209-216, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-30998570

RESUMEN

BACKGROUND/OBJECTIVE: The aim of this cross-sectional study was to explore which factors affect the impact of musculoskeletal ultrasound (MUS) on the treatment proposal among rheumatologists with different degree of experience. METHODS: Sixteen clinical vignettes summarized data from rheumatoid arthritis (RA) outpatients; vignettes included clinical evaluation and a blank section for a first treatment proposal; MUS information was then added, based on German Ultrasound score, followed by a blank section for treatment re-consideration, if applicable. During a 6 months period, each vignette was concomitantly presented to six trainees and six senior rheumatologists (SR); three SR had ≥15 years of experience. Participants were blinded to colleagues' responses. Appropriated statistics were used. RESULTS: Vignettes included data from female patients, who had a mean ± SD age of 43.3 ± 9 years, 7.6 ± 3.5 years of disease duration and comorbidities (68.8%). MUS induced treatment modification in 24% of evaluations, with similar percentage among SR and trainees. Within SR, more experienced rheumatologists (≥15 years) never translated MUS findings in a different treatment proposal, compared to 34% of those with lesser experience, p ≤ 0.0001. There were 60 clinical scenarios each, with remission and moderate disease activity, and 36 clinical scenarios each, with low and high disease activity. MUS-induced treatment modifications were more frequent in scenarios with low and moderate disease activity, compared to remission and high disease activity, p = 0.008. CONCLUSIONS: Physician's experience and disease activity level affect the impact of MUS on the treatment decision in RA outpatients. RA patients with intermediate disease activity may benefit from MUS incorporation to standard assessments.


Asunto(s)
Antirreumáticos/uso terapéutico , Artritis Reumatoide/diagnóstico por imagen , Artritis Reumatoide/tratamiento farmacológico , Competencia Clínica , Toma de Decisiones , Pautas de la Práctica en Medicina/estadística & datos numéricos , Adulto , Estudios Transversales , Femenino , Humanos
7.
Arch Microbiol ; 196(8): 557-63, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24853284

RESUMEN

To determine the concentration of bacteria in a sample is important in the food industry, medicine and biotechnology. A disadvantage of the plate-counting method is that a microorganism colony could arise from one cell or from many cells. The other standard methodology, known as optical density determination, is based on the turbidity of a suspension and registers all bacteria, dead and alive. In this article, dynamic light scattering is proposed as a fast and reliable method to determine bacterial viability and, consequently, time evolution. Escherichia coli was selected because this microorganism is well known and easy to handle. A correlation between the data from these three techniques was obtained. We were able to calculate the growth rate, usually determined by plate counting or optical density measurement, using dynamic light scattering and to predict bacterial behavior. An analytical relationship between the colony forming units and the light scattered intensity was also deduced.


Asunto(s)
Escherichia coli/fisiología , Viabilidad Microbiana , Luz , Tamaño de la Partícula , Dispersión de Radiación
8.
PLoS One ; 19(5): e0298776, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38805499

RESUMEN

The output signals in natural dyes-based solar cells (DSSC) can be either rising or decaying depending on the type of ions present in the system; these ions called added ions, are introduced by the additives: mordant and brighteners. The photon-dye interaction produces electrons, which eventually reach the electrode giving place to a superficially charged electrode in contact with an electrolyte where are the added ions. This combination produces, automatically, an electrical double-layer EDL structure which has important effects on the performance of the system: a) the added ions control, to a large extent, the initial shape of the output signal, giving rise to rising or decaying profiles; b) it is possible to store large amounts of energy and charge at high electric fields. This structure is found in many other systems that have a surface charged in contact with an electrolyte like piezoelectric materials in human body. This assertion was supported by determining important parameters such as the force between charged surfaces on both sides of the interface, the charge density, the energy density, and the capacitance. The Debye length has very small values then, many important quantities depend on this; it is possible to obtain large values for energy UDL ~ 3.6x105 Jm-3 and charge density ρDL ≈ 1.1x107 Cm-3 for double layer capacitors; these values are orders of magnitude larger than the corresponding values for electrostatic capacitors: Uelec ≈ 4.5x10-3 Jm-3 and ρelec ≈ 1.2 Cm-3. A non-linear model was also developed to fit unstable oscillations found in the output profiles produced by abrupt lighting.


Asunto(s)
Colorantes , Capacidad Eléctrica , Energía Solar , Colorantes/química , Suministros de Energía Eléctrica , Electrodos
9.
Gels ; 10(3)2024 Mar 09.
Artículo en Inglés | MEDLINE | ID: mdl-38534608

RESUMEN

The repair of nervous tissue is a critical research field in tissue engineering because of the degenerative process in the injured nervous system. In this review, we summarize the progress of injectable hydrogels using in vitro and in vivo studies for the regeneration and repair of nervous tissue. Traditional treatments have not been favorable for patients, as they are invasive and inefficient; therefore, injectable hydrogels are promising for the treatment of damaged tissue. This review will contribute to a better understanding of injectable hydrogels as potential scaffolds and drug delivery system for neural tissue engineering applications.

10.
Polymers (Basel) ; 16(4)2024 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-38399857

RESUMEN

Three-dimensional (3D) hydrogels provide tissue-like complexities and allow for the spatial orientation of cells, leading to more realistic cellular responses in pathophysiological environments. There is a growing interest in developing multifunctional hydrogels using ternary mixtures for biomedical applications. This study examined the biocompatibility and suitability of human auricular chondrocytes from microtia cultured onto steam-sterilized 3D Chitosan/Gelatin/Poly(Vinyl Alcohol) (CS/Gel/PVA) hydrogels as scaffolds for tissue engineering applications. Hydrogels were prepared in a polymer ratio (1:1:1) through freezing/thawing and freeze-drying and were sterilized by autoclaving. The macrostructure of the resulting hydrogels was investigated by scanning electron microscopy (SEM), showing a heterogeneous macroporous structure with a pore size between 50 and 500 µm. Fourier-transform infrared (FTIR) spectra showed that the three polymers interacted through hydrogen bonding between the amino and hydroxyl moieties. The profile of amino acids present in the gelatin and the hydrogel was determined by ultra-performance liquid chromatography (UPLC), suggesting that the majority of amino acids interacted during the formation of the hydrogel. The cytocompatibility, viability, cell growth and formation of extracellular matrix (ECM) proteins were evaluated to demonstrate the suitability and functionality of the 3D hydrogels for the culture of auricular chondrocytes. The cytocompatibility of the 3D hydrogels was confirmed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, reaching 100% viability after 72 h. Chondrocyte viability showed a high affinity of chondrocytes for the hydrogel after 14 days, using the Live/Dead assay. The chondrocyte attachment onto the 3D hydrogels and the formation of an ECM were observed using SEM. Immunofluorescence confirmed the expression of elastin, aggrecan and type II collagen, three of the main components found in an elastic cartilage extracellular matrix. These results demonstrate the suitability and functionality of a CS/Gel/PVA hydrogel as a 3D support for the auricular chondrocytes culture, suggesting that these hydrogels are a potential biomaterial for cartilage tissue engineering applications, aimed at the regeneration of elastic cartilage.

11.
Int J Mol Sci ; 14(2): 4081-93, 2013 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-23429194

RESUMEN

Dye-Sensitized Solar Cells (DSSCs), based on TiO(2) and assembled using a dye from Beta vulgaris extract (BVE) with Tetraethylorthosilicate (TEOS), are reported. The dye BVE/TEOS increased its UV resistance, rendering an increase in the cell lifetime; the performance of these solar cells was compared to those prepared with BVE without TEOS. The efficiency η for the solar energy conversion was, for BVE and BVE/TEOS, of 0.89% ± 0.006% and 0.68% ± 0.006% with a current density Jsc of 2.71 ± 0.003 mA/cm2 and 2.08 ± 0.003 mA/cm2, respectively, using in both cases an irradiation of 100 mW/cm2 at 25 °C. The efficiency of the BVE solar cell dropped from 0.9 ± 0.006 to 0.85 ± 0.006 after 72 h of operation, whereas for the BVE/TEOS, the efficiency remained practically constant in the same period of time.

12.
Sci Prog ; 106(2): 368504231169714, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37141710

RESUMEN

Piezoelectric signals were obtained from samples based on hydroxyapatite (HAp) and collagen (C) containing different glucose (G) concentrations. HAp was obtained by coprecipitation using Ca2+ and HPO42- as precursor ions in solution. C and G were added at the beginning of the coprecipitation method during the HAp growth. The presence of glucose in HAp and collagen samples drastically reduces the voltage amplitudes and considerably increases the relaxation times of the piezoelectric signals. HAp and collagen are the main constituents of bone, muscle, etc., then, it is possible to use piezoelectric technology for local and early detection of high glucose concentrations: small pressures applied by electrodes or by actuators placed in appropriate places on the body to establish a background concentration and, from this, to determine regions of the body with high local glucose concentrations: weak signals and large relaxation times are associated with a diminishing in the sensitivity, and are indicative of the presence of regions of abnormally high glucose concentrations.


Asunto(s)
Diabetes Mellitus , Durapatita , Humanos , Colágeno , Diabetes Mellitus/diagnóstico , Glucosa
13.
Polymers (Basel) ; 15(9)2023 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-37177348

RESUMEN

Chitosan hydrogels are biomaterials with excellent potential for biomedical applications. In this study, chitosan hydrogels were prepared at different concentrations and molecular weights by freeze-drying. The chitosan sponges were physically crosslinked using sodium bicarbonate as a crosslinking agent. The X-ray spectroscopy (XPS and XRD diffraction), equilibrium water content, microstructural morphology (confocal microscopy), rheological properties (temperature sweep test), and cytotoxicity of the chitosan hydrogels (MTT assay) were investigated. XPS analysis confirmed that the chitosan hydrogels obtained were physically crosslinked using sodium bicarbonate. The chitosan samples displayed a semi-crystalline nature and a highly porous structure with mean pore size between 115.7 ± 20.5 and 156.3 ± 21.8 µm. In addition, the chitosan hydrogels exhibited high water absorption, showing equilibrium water content values from 23 to 30 times their mass in PBS buffer and high thermal stability from 5 to 60 °C. Also, chitosan hydrogels were non-cytotoxic, obtaining cell viability values ≥ 100% for the HT29 cells. Thus, physically crosslinked chitosan hydrogels can be great candidates as biomaterials for biomedical applications.

14.
J Nutr Biochem ; 105: 108996, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35331901

RESUMEN

While several studies have previously described the levels of one-carbon metabolism-related micronutrients in women with gestational diabetes mellitus (GDM) and their neonates, the results in these literature reports have been contradictory. We hypothesized that the concentrations of micronutrients involved in the one-carbon cycle are altered in pregnant women and their neonates by GDM, and that these changes could further modify the neonatal anthropometry. Micronutrient levels were measured in 123 pregnant women with normal glucose levels (M-ND) and their neonates (N-ND), as well as in 54 pregnant women with gestational diabetes (M-GDM) and their neonates (M-GDM). Folate and vitamin B12 levels were measured via competitive ELISA, and betaine, choline, and glycine levels were measured via ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS/MS). Vitamin B12 and Glycine were found to be higher in M-GDM compared to M-ND. N-GDM had higher levels of folic acid and vitamin B12 and lower levels of betaine and choline compared to N-ND. In general, neonates presented with high concentrations of micronutrients compared to their mothers, and the fetus/maternal ratio of micronutrients was higher among the N-ND as compared to the N-GDM. Micronutrients were also variably associated with anthropometric measurements. The association of betaine with neonatal anthropometry in N-GDM is highlighted. In summary, our results implicate a potential role of GDM in altering the levels of one-carbon metabolism-related micronutrients among pregnant women and their neonates. Likewise, our results also elucidate a potential association between the concentrations of micronutrients and the weight, height, and head circumference of neonates.


Asunto(s)
Diabetes Gestacional , Betaína , Peso al Nacer , Carbono , Colina , Femenino , Ácido Fólico , Glicina , Humanos , Recién Nacido , Micronutrientes , Madres , Embarazo , Espectrometría de Masas en Tándem , Vitamina B 12
15.
Pharmaceutics ; 14(9)2022 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-36145602

RESUMEN

Herein, we report the synthesis of Au nanoparticles (AuNPs) in chitosan (CTS) solution by chemically reducing HAuCl4. CTS was further functionalized with glycidyl methacrylate (chitosan-g-glycidyl methacrylate/AuNP, CTS-g-GMA/AuNP) to improve the mechanical properties for cellular regeneration requirements of CTS-g-GMA/AuNP. Our nanocomposites promote excellent cellular viability and have a positive effect on cytokine regulation in the inflammatory and anti-inflammatory response of skin cells. After 40 days of nanocomposite exposure to a skin wound, we showed that our films have a greater skin wound healing capacity than a commercial film (TheraForm®), and the presence of the collagen allows better cosmetic ave aspects in skin regeneration in comparison with a nanocomposite with an absence of this protein. Electrical percolation phenomena in such nanocomposites were used as guiding tools for the best nanocomposite performance. Our results suggest that chitosan-based Au nanocomposites show great potential for skin wound repair.

16.
J Nat Prod ; 74(3): 314-20, 2011 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-20879744

RESUMEN

An extract from the roots of Ligusticum porteri, orally administered to groups of normal and diabetic mice, showed significant hypoglycemic and antihyperglycemic effects. Experimental type-II DM was achieved by treating mice with streptozotocin 15 min after an injection of ß-nicotinamide adenine dinucleotide. (Z)-6,6',7,3'α-diligustilide (1), (Z)-ligustilide (2), 3-(Z)-butylidenephthalide (3), myristicin (4), and ferulic acid (5) were isolated from the active extract. When tested In Vivo, compounds 1-3 showed antihyperglycemic activity, with 3 being the most active. Compound 3 (56.2 mg/kg) decreased blood glucose levels in NAD-STZ-diabetic mice after an oral sucrose load, suggesting that its antihyperglycemic effect is due to inhibition of α-glucosidase at the intestinal level. Furthermore, 3 inhibited the activity of yeast-α-glucosidase (IC(50) 2.35 mM) in a noncompetitive fashion with a K(i) of 4.86 mM. Docking analysis predicted that 3 binds to the enzyme in a pocket close to the catalytic site, but different from that for acarbose, with a K(i) of 11.48 mM. Compounds 1 and 2 did not affect α-glucosidase In Vivo, but altered glucose absorption by a mechanism yet to be determined. The stimulatory effect of 5 on insulin secretion, present in high amounts in the extract, has been demonstrated in previous investigations. The present study provides scientific support of the use of L. porteri in Mexican folk medicine for the treatment of diabetes.


Asunto(s)
Glucemia/análisis , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Inhibidores de Glicósido Hidrolasas , Hipoglucemiantes/aislamiento & purificación , Hipoglucemiantes/farmacología , Ligusticum/química , Anhídridos Ftálicos/aislamiento & purificación , Anhídridos Ftálicos/farmacología , Acarbosa/farmacología , Administración Oral , Animales , Hipoglucemiantes/química , Insulina/sangre , Insulina/metabolismo , Secreción de Insulina , Medicina Tradicional , México , Ratones , Anhídridos Ftálicos/química , Estereoisomerismo , Estreptozocina/farmacología
17.
Int J Mol Sci ; 12(9): 5565-76, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-22016609

RESUMEN

The performance of a new dye-sensitized solar cell (DSSC) based in a natural dye extracted from the Bougainvillea spectabilis' bracts, is reported. The performance of this solar cell was compared with cells prepared using extract of the Bougainvillea glabra and mixture of both extracts; in both cases the pigments were betalains, obtained from Reddish-purple extract. These dyes were purified to different extents and used for the construction of solar cells that were electrically characterized. The materials were characterized using FTIR and UV-Vis. Solar cells were assembled using TiO(2) thin film on indium tin oxide (ITO)-coated glass; a mesoporous film was sensitized with the Bougainvillea extracts. The obtained solar energy conversion efficiency was of 0.48% with a current density J(SC) of 2.29 mA/cm(2) using an irradiation of 100 mW/cm(2) at 25 °C.


Asunto(s)
Betalaínas/química , Colorantes/química , Nyctaginaceae/química , Hojas de la Planta/química , Energía Solar , Betalaínas/aislamiento & purificación , Colorantes/aislamiento & purificación , Técnicas Electroquímicas/métodos , Vidrio/química , Microscopía Electrónica de Rastreo , Tamaño de la Partícula , Extractos Vegetales/química , Extractos Vegetales/aislamiento & purificación , Espectrofotometría , Espectroscopía Infrarroja por Transformada de Fourier , Compuestos de Estaño/química
18.
J Biomed Mater Res A ; 108(1): 81-93, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31502406

RESUMEN

Gelatin/chitosan/polyvinyl alcohol hydrogels were fabricated at different polymer ratios using the freeze-drying and sterilized by steam sterilization. The thermal stability, chemical structure, morphology, surface area, mechanical properties, and biocompatibility of hydrogels were evaluated by simultaneous thermal analysis, Fourier transform infrared spectroscopy, X-ray diffraction, confocal microscopy, adsorption/desorption of nitrogen, rheometry, and 3-4,[5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide cell viability assay (MTT assay), respectively. The samples showed a decomposition onset temperature below 253.3 ± 4.8°C, a semicrystalline nature, and a highly porous structure. Hydrogels reached the maximum water uptake in phosphate-buffered saline after 80 min, showing values from nine to twelve times their dry mass. Also, hydrogels exhibiting a solid-like behavior ranging from 2,567 ± 467 to 48,705 ± 2,453 Pa at 0.1 rad/s (low frequency). The sterilized hydrogels showed low cytotoxicity (cell viability > 70%) to the HT29-MTX-E12 cell line. Sterilized hydrogels by steam sterilization can be good candidates as scaffolds for tissue engineering applications.


Asunto(s)
Fenómenos Químicos , Quitosano/química , Quitosano/toxicidad , Hidrogeles/química , Hidrogeles/toxicidad , Esterilización , Rastreo Diferencial de Calorimetría , Muerte Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Elasticidad , Gelatina/química , Células HT29 , Humanos , Nitrógeno/química , Alcohol Polivinílico/química , Espectroscopía Infrarroja por Transformada de Fourier , Temperatura , Termogravimetría , Viscosidad , Agua/química , Difracción de Rayos X
19.
Ecol Evol ; 9(19): 11078-11088, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31641456

RESUMEN

Strategic conservation efforts for cryptic species, especially bats, are hindered by limited understanding of distribution and population trends. Integrating long-term encounter surveys with multi-season occupancy models provides a solution whereby inferences about changing occupancy probabilities and latent changes in abundance can be supported. When harnessed to a Bayesian inferential paradigm, this modeling framework offers flexibility for conservation programs that need to update prior model-based understanding about at-risk species with new data. This scenario is exemplified by a bat monitoring program in the Pacific Northwestern United States in which results from 8 years of surveys from 2003 to 2010 require updating with new data from 2016 to 2018. The new data were collected after the arrival of bat white-nose syndrome and expansion of wind power generation, stressors expected to cause population declines in at least two vulnerable species, little brown bat (Myotis lucifugus) and the hoary bat (Lasiurus cinereus). We used multi-season occupancy models with empirically informed prior distributions drawn from previous occupancy results (2003-2010) to assess evidence of contemporary decline in these two species. Empirically informed priors provided the bridge across the two monitoring periods and increased precision of parameter posterior distributions, but did not alter inferences relative to use of vague priors. We found evidence of region-wide summertime decline for the hoary bat ( λ ^  = 0.86 ± 0.10) since 2010, but no evidence of decline for the little brown bat ( λ ^  = 1.1 ± 0.10). White-nose syndrome was documented in the region in 2016 and may not yet have caused regional impact to the little brown bat. However, our discovery of hoary bat decline is consistent with the hypothesis that the longer duration and greater geographic extent of the wind energy stressor (collision and barotrauma) have impacted the species. These hypotheses can be evaluated and updated over time within our framework of pre-post impact monitoring and modeling. Our approach provides the foundation for a strategic evidence-based conservation system and contributes to a growing preponderance of evidence from multiple lines of inquiry that bat species are declining.

20.
Gac Med Mex ; 144(1): 1-6, 2008.
Artículo en Español | MEDLINE | ID: mdl-18619050

RESUMEN

BACKGROUND: Gene PMP22 is duplicated in patients with CMT1A. Duplication is due to an unequal chromatid interchange during meiosis that takes place between two 24 Kb regions named REP-CMT1A proximal and distal sites. Homology is approximately 98%. Within each one of the sites we find zones termed hot spots where a greater number of variants and mutations could give origin to an unequal interchange. The aim of this study was to design a set of probes to create a microarray that could detect the presence of variants and mutation points in distal and proximal REP sites among patients with CMT1A. MATERIAL AND METHODS: With reported sequences of distal and proximal REPs, we determined hot spot sites within proximal and distal regions. These sequences were aligned and matched, hence 12 zones were detected. RESULTS AND CONCLUSIONS: Twenty four probes were designed and analyzed using the Genosensor Probe Designer program. Probes could be synthesized and used in a microarray that is able to find variations and mutation points and facilitates diagnosis of patients with CMT1A.


Asunto(s)
Enfermedad de Charcot-Marie-Tooth/genética , Proteínas de la Mielina/genética , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Proteínas/genética , Humanos
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