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C.J. González-Pérez1,I. Vargas-Arispuro,E. Aispuro-Hernández,C.L. Aguilar-Gil,Y.E. Aguirre-Guzmán,A. Castillo,A. Hernández-Mendoza,J.F. Ayala-Zavala,M.A. Martínez-Téllez1 한국미생물·생명공학회 2019 한국미생물·생명공학회지 Vol.47 No.2
The consumption of fresh vegetables has been related to recurrent outbreaks of foodborne diseases (FBD) worldwide. Therefore, the development of effective alternative technologies is necessary to improve the safety of these products. This study aimed to isolate and identify epiphytic lactic acid bacteria (LAB) from fresh fruits and leafy vegetables and characterize their antagonistic capacity due to their ability to produce bacteriocins or antibacterial compounds. For this, 92 LAB isolates from fruits and leafy vegetables were screened for antagonistic activity. Two strains with the highest and broadest antagonistic activities were selected for further characterization; one from cantaloupe melon (strain CM175) and one from cilantro leaves (strain C15). The cell-free supernatants (CFS) of CM175 and C15 were found to exhibit antagonistic activity against FBD-causing pathogens. The CM175 and C15 strains were identified as Pediococcus pentosaceus and Lactobacillus graminis, respectively. Notably, the P. pentosaceus CM175 CFS stopped the growth of Salmonella Typhimurium, Salmonella Saintpaul, Staphylococcus aureus, and Listeria monocytogenes, and delayed Escherichia coli O157:H7 growth. Moreover, L. graminis C15 CFS delayed the growth of all indicator pathogens, but did not completely stop it. Organic acids and bacteriocin-like molecules were determined to be possibly exerting the observed antagonistic activity of the identified LAB strains. Thus, application of the antagonistic compounds produced by Pediococcus pentosaceus and Lactobacillus graminis could be a novel and ecological strategy in developing antimicrobial biopreservatives for the food industry and mitigating FBD by reducing the biological contamination in fruit and vegetable orchards, mainly via their potential in controlling both gram-negative and gram-positive pathogenic bacteria.
Intraumbilical versus intramuscular oxytocin in the management of the third stage of labor
Silvia Waleska Bu,César Alas-Pineda,David Aguilar-Andino,Dalton Argean Norwood,Kristhel Gaitán-Zambrano,Mario Pinto-Romero 대한산부인과학회 2023 Obstetrics & Gynecology Science Vol.66 No.2
ObjectiveTo compare the effect of intraumbilical vein oxytocin injection with standard management in reducing blood loss during the third and fourth stages of labor. Acute complications threaten the mother’s life during the third and fourth stages of labor. The most common complication is postpartum hemorrhage, which remains a leading cause of maternal mortality, particularly in developing countries. MethodsA randomized controlled trial was conducted in the Gynecology and Obstetrics Department of Leonardo Mart?nez Valenzuela Hospital from January to June 2021. A probabilistic sample was used: 332 pregnant patients were enrolled in the study and randomized into the case (166 patients) and control (166 patients) groups. The volume of blood lost was compared between the groups. ResultsThe median estimated blood loss was 120 mL (interquartile range [IQR], 80-218.75 mL). There was a statistically significant difference between the groups, showing less estimated blood loss in the international unit group with a median of 80 mL (IQR, 60-100 mL) (P<0.001), and 200 mL (IQR, 143.75-300 mL) in the intramuscular (IM) group, highlighting that 66.8% of the IM group had an estimated blood loss >251 mL. ConclusionAny reduction in bleeding during labor is clinically relevant because it improves patient prognosis. The use of intraumbilical oxytocin injection with active management of the third stage of labor significantly reduced postpartum blood loss and the duration of the third stage compared with the IM group.
A novel six-degrees-of-freedom series-parallel manipulator
J. Gallardo-Alvarado,R. Rodríguez-Castro,C. R. Aguilar-Nájera,L. Pérez-González 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.6
This paper addresses the description and kinematic analyses of a new non-redundant series-parallel manipulator. The primary feature of the robot is to have a decoupled topology consisting of a lower parallel manipulator, for controlling the orientation of the coupler platform,assembled in series connection with a upper parallel manipulator, for controlling the position of the output platform, capable to provide arbitrary poses to the output platform with respect to the fixed platform. The forward displacement analysis is carried-out in semi-closed form solutions by resorting to simple closure equations. On the other hand; the velocity, acceleration and singularity analyses of the manipulator are approached by means of the theory of screws. Simple and compact expressions are derived here for solving the infinitesimal kinematics by taking advantage of the concept of reciprocal screws. Furthermore, the analysis of the Jacobians of the robot shows that the lower parallel manipulator is practically free of singularities. In order to illustrate the performance of the manipulator, a numerical example which consists of solving the inverse/forward kinematics of the series-parallel manipulator as well as its singular configurations is provided.
Velueta D. A. Pantoja,Ramírez S. J. Figueroa,Sierra J. M.,Escobar B.,Ucán C. A. Aguilar,Rosas G. 한국탄소학회 2022 Carbon Letters Vol.32 No.6
The biocarbon (SKPH) was obtained from Sargassum spp., and it was evaluated electrochemically as support for the CO2 reduction. The biocarbon was synthesized and activated with KOH, obtaining a high surface area (1600 m2 g−1) due to the activation process. Graphitic carbon formation after pyrolysis was confirmed by Raman spectroscopy. The XRD results show that SKPH has an amorphous structure with peaks corresponding to typical amorphous carbonaceous materials. FTIR was used to determine the chemical structure of SKPH. The bands at 3426, 2981, 2851, and 1604 cm−1 correspond to O–H, C-H, and C-O stretching vibrations, respectively. Then, it compares SKPH films with different carbon films using two electrolytic systems with and without charge transfer. The SKPH film showed a capacitive behavior in the KOH, H2SO4, and, KCl systems; in the acid medium, the presence of a redox couple associated with carbon functional groups was shown. Likewise, in the [Fe(CN)6]−3 and Cu(II) systems, the charge transfer process coupled with a capacitive behavior was described, and this effect is more noticeable in the [Fe(CN)6]−3 system. Electrodeposition of copper on SKPH film showed two stages Cu(NH3)2+4 /Cu(NH3)+2 and Cu(NH3)+2/Cu in ammonia media. Hydrogen formation and the activity of CO2 are observed on SKPH film and are favored by the carbon’s surface chemistry. Cu/SKPH electrocatalyst has a catalytic effect on electrochemical reduction of CO2 and inhibition of hydrogen formation. This study showed that the SKPH film electrode responds as a capacitive material that can be used as an electrode for energy storage or as metal support.
E. García-Hernández,C.G. Aguilar-Madera,E.C. Herrera-Hernández,R. Ocampo-Pérez,E. Bailón-García,Farid B. Cortés 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.93 No.-
In this work, a mathematical formulation based on fundamental principles of momentum and masstransport with a kinetic adsorption model at the liquid-solid interface is proposed. This formulation wasnumerically solved and used for the interpretation of adsorption rate data of phenol onto an activatedcarbon cloth in a stirred tank adsorber under different agitation rates. The mathematical model solutionwas compared with the obtained by mathematical models that neglect the local velocity andconcentration profiles in the solution; external mass transfer model (EMTM) and thefirst-order kineticmodel (FOM). The results showed that under all studied stirring speeds (30 200 rpm) the proposedmodel was able to capture the dynamics of the concentration decay curves, while EMTM and FOM modelswere only able to interpret the data at high stirring speeds, indicating that velocity profiles play animportant role during phenol adsorption. Particular “wake zones” were identified behind the mobileadsorbent, which importantly promotes the transport of solute toward the activated carbon cloth. As aresult, it was found that convective transport is much more important than diffusive transport in thesolution.
Pectin from Passion Fruit Fiber and Its Modification by Pectinmethylesterase
Contreras-Esquivel, Juan Carlos,Aguilar, Cristobal N.,Montanez, Julio C.,Brandelli, Adriano,Espinoza-Perez, Judith D.,Renard, Catherine M.G.C. The Korean Society of Food Science and Nutrition 2010 Preventive Nutrition and Food Science Vol.15 No.1
Passion fruit fiber pectin gels represent a new alternative pectin source with potential for food and non-food applications on a commercial scale. Pectic polysaccharides were extracted from passion fruit (Passiflora edulis) fiber using citric acid as a clean catalyst and autoclaved for 20 to 60 min at $121^{\circ}C$. The best condition of pectin yield with the highest molecular weight was obtained with 1.0% of citric acid (250 mg/g dry passion fruit fiber pectin) for 20 min of autoclaving. Spectroscopic analyses by Fourier transform infrared, enzymatic degradation reactions, and ion-exchange chromatography assays showed that passion fruit pectin extracted for 20 min was homogeneous high methoxylated pectin (70%). Gel permeation analysis confirmed that the pectin extract obtained by autoclaving by 20 min showed higher molecular weights than those autoclaved for 40 and 60 min. Passion fruit pectin extracted for 20 min was enzymatically modified with fungal pectinmethylesterase to create restructured gels. Short autoclave treatment (20 min) with citric acid as extractant resulted in a significant increase of gel strength, improving pectin extraction in terms of functionality. The treatment of solubilized material (pectic polysaccharides) in the presence of insoluble material (cellulose and hemicellulose) with pectinmethylesterase and calcium led to the creation of a stiffer passion fruit fiber pectin gel, while syneresis was not observed.
Optimization of Tannase Production by Aspergillus niger in Solid-State Packed-Bed Bioreactor
( Rodriguez Duran Luis ),( Juan C. Contreras Esquivel ),( Raul Rodriguez ),( L. Arely Prado Barragan ),( Cristobal N. Aguilar ) 한국미생물 · 생명공학회 2011 Journal of microbiology and biotechnology Vol.21 No.9
Tannin acyl hydrolase, also known as tannase, is an enzyme with important applications in the food, feed, pharmaceutical, and chemical industries. However, despite a growing interest in the catalytic properties of tannase, its practical use is very limited owing to high production costs. Several studies have already demonstrated the advantages of solid-state fermentation (SSF) for the production of fungal tannase, yet the optimal conditions for enzyme production strongly depend on the microbial strain utilized. Therefore, the aim of this study was to improve the tannase production by a locally isolated A. niger strain in an SSF system. The SSF was carried out in packed-bed bioreactors using polyurethane foam as an inert support impregnated with defined culture media. The process parameters influencing the enzyme production were identified using a Plackett-Burman design, where the substrate concentration, initial pH, and incubation temperature were determined as the most significant. These parameters were then further optimized using a Box-Behnken design. The maximum tannase production was obtained with a high tannic acid concentration (50 g/l), relatively low incubation temperature (30oC), and unique low initial pH (4.0). The statistical strategy aided in increasing the enzyme activity nearly 1.97-fold, from 4,030 to 7,955 U/l. Consequently, these findings can lead to the development of a fermentation system that is able to produce large amounts of tannase in economical, compact, and scalable reactors.
( Cecilia Perez-cruz ),( Carlos N. Cano-gonzalez ),( Jose Fuentes ),( Nagamani Balagurusamy ),( Carolina E. Vita ),( Roque A. Hours ),( Cristobal N. Aguilar ),( Sebastian F. Cavalitto ),( Juan C. Cont 한국키틴키토산학회 2018 한국키틴키토산학회지 Vol.23 No.3
Aspergillus niger biomass, an industrial by-product of citric acid fermentation is an emergent source of glycoderivatives with applications in biofuel, cosmetics, feed, energy, food, medicine, and nanotechnology. In this study, the effect of purified neutral protease for deprotenization of fungal biomass studied at various levels (0, 5, 10, 20 and 40 U/100 mg of biomass) and the saccharification of fungal biomass was evaluated with amylolytic enzymes and chitosanases. The efficiency of deproteinization of fungal biomass was based on the enzyme concentration and contact time. Protease at a concentration of 20 U/100 mg of dry biomass and with a contact time of 8 h achieved 30% final deproteinization. No effect on saccharification of A. niger biomass was observed by treatment with purified amylolytic enzymes. Meanwhile, the endo- and exo-chitosanases treatment yielded 54 g of g reducing sugars (equivalent to amino sugars)/ kg of fungal biomass, which can be employed for tailor-made carbohydrate production.