ANDRES ARANGO MEJIA - Academia.edu (original) (raw)
Papers by ANDRES ARANGO MEJIA
Objectives/Interrogation: To evaluate the anatomic distribution of the main and terminal branches... more Objectives/Interrogation: To evaluate the anatomic distribution of the main and terminal branches of the axillary nerve into the deltoid muscle through dissection and measurement in adult cadavers and to find the best donor for nerve transfer surgery based upon its distribution. Methods: Anatomic[for full text, please go to the a.m. URL]
Revista Estomatología, 2017
Objective: To characterize oclussal relationships in primary and early mixed dentition and arch d... more Objective: To characterize oclussal relationships in primary and early mixed dentition and arch dimensions in sagittal, transversal and vertical planes. Materials and methods: This descriptive study considered a convenience sample of 107 children with an average age of 5.69 years (59 girls and 48 boys) registered in ten schools. Panoramic and cephalometric radiographs and study models were taken according to validated protocols. Panoramic radiographs showed the position and angulation of the first permanent molars. Results: 84% of patients in the study were characterized by having complete dentition, having a left and right molar relationships in flat terminal plane, an increased vertical overbite, an anterior superior width in a range between 27 and 32 mm, a superior posterior width between 32 and 39 mm, an anterior inferior width between 22 and 27 mm and an inferior posterior width between 39 and 46 mm. The inclination angle of the first superior molar is between 25 and 36 degrees...
Revista Colombiana De Gastroenterologia, Jun 1, 2006
Monodisperse wax emulsions were prepared by electrospraying of melt wax. The size of the emulsion... more Monodisperse wax emulsions were prepared by electrospraying of melt wax. The size of the emulsions was tailored by varying experimental parameters of the electrospray, such as the flow rate of the discontinuous phase, its electric conductivity, and the applied voltage. The monodispersity of the emulsions was greatly influenced by the surface tension and density of the collection liquid. We also demonstrated the fabrication of uniform wax microdisks using the phase transition of wax molecules inside these emulsions.
Nanoparticles with quasi two-dimensional shapes serve as building blocks for discotic colloidal l... more Nanoparticles with quasi two-dimensional shapes serve as building blocks for discotic colloidal liquid crystals. However, due to difficulty of synthesis and especially shape-tuning of disk-shaped nanoparticles, good model systems for the study of discotic colloidal liquid crystals are hard to found. α-zirconium phosphate (ZrP) crystals synthesized through hydrothermal treatment has regular disk shapes and controllable size, thickness, as well as size polydispersity. We experimentally illustrate that aqueous suspensions of these ZrP disks form stable liquid crystal phase easily. By choosing the thickness of the disks, an iridescent liquid crystal phase has been achieved. The critical concentration of the phase transition was found to be dependent on aspect ratios. We will also discuss our recent results on the phase diagram of discotic liquid crystals as a function of aspect ratio and particle concentration using ZrP monolayers and wax disks.
We report the fabrication of temperature-responsive nematic hydrogels using large aspect ratio (ξ... more We report the fabrication of temperature-responsive nematic hydrogels using large aspect ratio (ξ = diameter/thickness) zirconium phosphate (ZrP) monolayers embedded into a polymer network. To achieve an ordered nanostructure, these monolayers were immersed into a monomer solution. The monolayer suspension was macroscopically oriented by shear flow and polymerized in situ to obtain a nematic hydrogel. The alignment of the large aspect ratio nano-sheets by a weak external stimulus enables the formation of nematic textures during hydrogel formation. Cross-polarizing micrographs revealed the liquid crystallinity of the nematic hydrogels. We analyzed the influence of the initiator and the catalyst on the nematic textures. Furthermore, by setting the temperature above 32ºC, we found that the nematic hydrogel experienced volume shrinking evolving the variation of the nematic textures. Finally, at low monolayer concentrations the hydrogels presented an isotropic-nematic (I-N) order transit...
We introduce the use of zirconium phosphate (Zr(HPO4)2·H2O, α-ZrP) crystals as a dust explosion s... more We introduce the use of zirconium phosphate (Zr(HPO4)2·H2O, α-ZrP) crystals as a dust explosion suppressant. The influence of size and crystallinity of the crystals during a dust explosion was systematically studied. During α-ZrP synthesis, the size and crystallinity of the pristine platelets were tailored by adjusting the phosphoric acid (H3PO4) concentration and the reaction time [1, 2]. The thermal stability of the mixtures containing corn starch and ZrP crystals at different size and crystallinity was evaluated using thermo gravimetric analysis (TGA) and differential scanning calorimeter (DSC). In addition, the maximum pressure (Pmax) and the maximum pressure rise ((dP/dt)max) of these mixtures were obtained by performing dust explosion tests using a 36 L vessel. As a reference, monoammonium phosphate (NH4H2PO4, MAP) was utilized. MAP is a widely studied compound commonly used as an explosion suppressant [3, 4]. From experiments, TGA revealed a higher thermal stability of mixtur...
Advanced Materials Research, 2013
We performed systematic experiments on the synthesis of layered crystal α-ZrP and revealed the co... more We performed systematic experiments on the synthesis of layered crystal α-ZrP and revealed the control of size, aspect ratio and size polydispersity of disk-shaped crystals. The growth of the disks is mediated by oriented attachment, taking place continuously throughout the hydrothermal treatment between various sized disks. The master of the synthesis of layered crystals will contribute to various applications such as the nanocomposites and liquid crystals.
Industrial & Engineering Chemistry Research, 2014
The influence of size and crystallinity on the efficiency of dust explosion inhibition was system... more The influence of size and crystallinity on the efficiency of dust explosion inhibition was systematically studied. We fractionated ammonium phosphate monobasic (MAP, NH 4 H 2 PO 4) and dibasic (DAP, (NH 4) 2 HPO 4) at different size ranges, and we synthesized zirconium phosphate (α-ZrP, Zr(HPO 4) 2 •H 2 O) at varying sizes and crystalline levels. To evaluate the inhibitor efficiency of each material, we analyzed the thermal stability of mixtures containing cornstarch and DAP/α-ZrP/MAP, using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). In addition, the dust explosion severity (i.e., maximum pressure (P max) and maximum rate of pressure rise ((dP/dt) max)) of these mixtures was obtained by performing dust explosion tests using a 36 L vessel. The experimental results show that α-ZrP provides the highest thermal stability but the lowest rate of heat absorption of the mixtures. DAP exhibited a lower thermal stability in comparison to α-ZrP and MAP, but exhibits a remarkable rate of energy absorption during its decomposition reaction. In general, the efficiency of dust inhibitors increased by decreasing particle size. Particularly, DAP and MAP presented a critical diameter (i.e., 128 μm), where the inhibitor efficiency was enhanced. However, the performance of α-ZrP as an inhibitor was not considerably affected by the variation of particle size and crystalline level. Finally, a semiempirical model was developed to identify the factors dominating the reduction of cornstarch explosion severity. In agreement with aforementioned results, the simplified model presents a critical diameter below which the inhibitor efficiency is significantly improved.
Proceedings of the CUBE International Information Technology Conference on - CUBE '12, 2012
Soft Matter, 2013
ABSTRACT We developed Pickering foams highly stabilized by high-aspect-ratio (ξ = diameter/thickn... more ABSTRACT We developed Pickering foams highly stabilized by high-aspect-ratio (ξ = diameter/thickness) nano-sheets. The effects of particle aspect ratio, concentration, and hydrophobicity were also investigated. To our knowledge, our study provides the first experimental evidence of the effect of particle aspect ratio on particle-stabilized foams. The adsorption properties of these highly anisotropic nano-sheets are strongly affected by their small thickness and large lateral size (i.e., two-dimensional). These high-aspect-ratio nano-sheets were obtained by exfoliation of α-zirconium phosphate (ZrP) crystals with propylamine (C3H7NH2, PA). The hydrophobicity of the nano-sheets was tailored by adjusting the PA:ZrP molar ratio in the suspension. The morphology and stability of the foam depend on the nano-sheet aspect ratio and concentration as well as on the PA:ZrP molar ratio. Here, we found that using low and high aspect ratio nano-sheets having a high and an intermediate degree of hydrophobicity, respectively, is the successful formula to obtain high foam stability. The aqueous foams were characterized by optical and cross-polarized micrographs. Scanning electron microscopy (SEM) micrographs of dried foams revealed the adsorption of the PA–ZrP nano-sheets on the air–water interface. The foam stability was studied by measuring the foam and the water volume as a function of time to obtain the foam decay and water drainage rate, respectively. We also observed that the foams were stabilized by jammed layers of nano-sheets located in the bulk and at the air–water interface. These layers of particles prevent air diffusion between the bubbles, hence arresting Ostwald ripening and coalescence.
Soft Matter, 2012
Supporting Information 1. Particle-stabilized emulsions Adsorption of homogeneous and amphiphilic... more Supporting Information 1. Particle-stabilized emulsions Adsorption of homogeneous and amphiphilic particles at liquid-liquid interfaces Fig. S1. Illustrations of (a) a disk-shaped Janus particle and (b) its interfacial adsorption. Modified according to Nonomura et al. 1 Using homogeneous spheres, the highest stability of the resulting Pickering emulsion occurs when the three-phase contact angle among the particle, hydrophobic, and hydrophilic fluids is around 90º. 2-7 Hydrophobic particles will stabilize water-in-oil emulsions having a contact angle slightly greater than 90°, whereas hydrophilic particles will
Powder Technology, 2014
ABSTRACT This paper reports experimental results elucidating the effect of particle size polydisp... more ABSTRACT This paper reports experimental results elucidating the effect of particle size polydispersity (sigma(D)) on the explosion severity of aluminum dust. Five mixtures with a median diameter (D-50) of 15 mu m and sigma(D) values of 0.95, 1.17, 1.48, 1.87, and 2.51, were systematically prepared by mixing original aluminum samples having narrow size distributions. The explosion severity of each sample was determined in a 36 L dust explosion vessel by measuring the maximum pressure (P-max), the maximum rate of pressure rise ((dP/dt)(max)), and the deflagration index (K-St). Interestingly, we found that values of P-max and K-St revealed an increase in explosion severity as sigma(D) increases, where the latter presented a more dramatic effect due to the contribution of fine particles on the combustion kinetics. The effect of dust concentration on the explosion propagation was analyzed comparing the time span to reach (dP/dt)(max), (tau), during a dust explosion. tau was obtained from the experimental pressure traces of the original samples and their mixtures. The values of P-max and K-St, were plotted as a function of the median diameter (D-50) and the volume-(D-4,D-3) and surface-(D-3,D-2) weighted mean diameter. We observed that D-3,D-2 provided a better description of the average sample size and D-50 is inadequately related to the real hazard potential of aluminum dust. Therefore, we suggest that the explosion hazard characterization of these types of materials should be reported in terms of D-3,D-2 and sigma(D).
Physical Review Letters, 2012
Phase behavior of charged disk suspensions displays strong dependence on ionic strengths, as the ... more Phase behavior of charged disk suspensions displays strong dependence on ionic strengths, as the interplay between excluded volume and electrostatic interactions determines the formation of glasses, gels, and liquid crystal states. The various ions in natural soil or brine, however, could present additional effects, especially considering most platelet structures bear momentous ionexchange capacity. Here we observed how ion exchange modulates and controls the interaction between individual disks and leads to unconventional phase transitions from isotropic gel to nematic gel, and finally to nematic liquid crystals.
Physical Review E, 2012
We demonstrate the strong dependency of the IN transition of discotic suspensions on the aspect r... more We demonstrate the strong dependency of the IN transition of discotic suspensions on the aspect ratio (ξ = thickness/diameter) via control of the sizes of pristine ZrP crystals and subsequent exfoliation to monolayers. The size-fractionation of the IN transition facilitates the analysis of the effect of polydispersity. A systematic variation of the aspect ratio in the low aspect ratio region (0.001 < ξ < 0.01) showed that the IN transition volume fraction increases with aspect ratio in agreement with computer simulations. It was found that the transition volume fractions scale with aspect ratio φ I,N =mξ 1.36 ± 0.07 , where the prefactor m strongly depends on size polydispersity for φ N , but does not depend on size polydispersity for φ I , with φ I and φ N being the volume fractions of the isotropic and the nematic phases on the cloud curves, respectively.
Obesity Surgery, 2007
Bariatric surgery, mainly laparoscopic Roux-en-Y gastric bypass, is widely considered to be the b... more Bariatric surgery, mainly laparoscopic Roux-en-Y gastric bypass, is widely considered to be the best operation for the treatment of morbid obesity. Leak or fistula of the gastrojejunostomy is a feared complication of this procedure. A patient who developed a gastrocutaneous fistula and was successfully managed endoscopically is reported.
Objectives/Interrogation: To evaluate the anatomic distribution of the main and terminal branches... more Objectives/Interrogation: To evaluate the anatomic distribution of the main and terminal branches of the axillary nerve into the deltoid muscle through dissection and measurement in adult cadavers and to find the best donor for nerve transfer surgery based upon its distribution. Methods: Anatomic[for full text, please go to the a.m. URL]
Revista Estomatología, 2017
Objective: To characterize oclussal relationships in primary and early mixed dentition and arch d... more Objective: To characterize oclussal relationships in primary and early mixed dentition and arch dimensions in sagittal, transversal and vertical planes. Materials and methods: This descriptive study considered a convenience sample of 107 children with an average age of 5.69 years (59 girls and 48 boys) registered in ten schools. Panoramic and cephalometric radiographs and study models were taken according to validated protocols. Panoramic radiographs showed the position and angulation of the first permanent molars. Results: 84% of patients in the study were characterized by having complete dentition, having a left and right molar relationships in flat terminal plane, an increased vertical overbite, an anterior superior width in a range between 27 and 32 mm, a superior posterior width between 32 and 39 mm, an anterior inferior width between 22 and 27 mm and an inferior posterior width between 39 and 46 mm. The inclination angle of the first superior molar is between 25 and 36 degrees...
Revista Colombiana De Gastroenterologia, Jun 1, 2006
Monodisperse wax emulsions were prepared by electrospraying of melt wax. The size of the emulsion... more Monodisperse wax emulsions were prepared by electrospraying of melt wax. The size of the emulsions was tailored by varying experimental parameters of the electrospray, such as the flow rate of the discontinuous phase, its electric conductivity, and the applied voltage. The monodispersity of the emulsions was greatly influenced by the surface tension and density of the collection liquid. We also demonstrated the fabrication of uniform wax microdisks using the phase transition of wax molecules inside these emulsions.
Nanoparticles with quasi two-dimensional shapes serve as building blocks for discotic colloidal l... more Nanoparticles with quasi two-dimensional shapes serve as building blocks for discotic colloidal liquid crystals. However, due to difficulty of synthesis and especially shape-tuning of disk-shaped nanoparticles, good model systems for the study of discotic colloidal liquid crystals are hard to found. α-zirconium phosphate (ZrP) crystals synthesized through hydrothermal treatment has regular disk shapes and controllable size, thickness, as well as size polydispersity. We experimentally illustrate that aqueous suspensions of these ZrP disks form stable liquid crystal phase easily. By choosing the thickness of the disks, an iridescent liquid crystal phase has been achieved. The critical concentration of the phase transition was found to be dependent on aspect ratios. We will also discuss our recent results on the phase diagram of discotic liquid crystals as a function of aspect ratio and particle concentration using ZrP monolayers and wax disks.
We report the fabrication of temperature-responsive nematic hydrogels using large aspect ratio (ξ... more We report the fabrication of temperature-responsive nematic hydrogels using large aspect ratio (ξ = diameter/thickness) zirconium phosphate (ZrP) monolayers embedded into a polymer network. To achieve an ordered nanostructure, these monolayers were immersed into a monomer solution. The monolayer suspension was macroscopically oriented by shear flow and polymerized in situ to obtain a nematic hydrogel. The alignment of the large aspect ratio nano-sheets by a weak external stimulus enables the formation of nematic textures during hydrogel formation. Cross-polarizing micrographs revealed the liquid crystallinity of the nematic hydrogels. We analyzed the influence of the initiator and the catalyst on the nematic textures. Furthermore, by setting the temperature above 32ºC, we found that the nematic hydrogel experienced volume shrinking evolving the variation of the nematic textures. Finally, at low monolayer concentrations the hydrogels presented an isotropic-nematic (I-N) order transit...
We introduce the use of zirconium phosphate (Zr(HPO4)2·H2O, α-ZrP) crystals as a dust explosion s... more We introduce the use of zirconium phosphate (Zr(HPO4)2·H2O, α-ZrP) crystals as a dust explosion suppressant. The influence of size and crystallinity of the crystals during a dust explosion was systematically studied. During α-ZrP synthesis, the size and crystallinity of the pristine platelets were tailored by adjusting the phosphoric acid (H3PO4) concentration and the reaction time [1, 2]. The thermal stability of the mixtures containing corn starch and ZrP crystals at different size and crystallinity was evaluated using thermo gravimetric analysis (TGA) and differential scanning calorimeter (DSC). In addition, the maximum pressure (Pmax) and the maximum pressure rise ((dP/dt)max) of these mixtures were obtained by performing dust explosion tests using a 36 L vessel. As a reference, monoammonium phosphate (NH4H2PO4, MAP) was utilized. MAP is a widely studied compound commonly used as an explosion suppressant [3, 4]. From experiments, TGA revealed a higher thermal stability of mixtur...
Advanced Materials Research, 2013
We performed systematic experiments on the synthesis of layered crystal α-ZrP and revealed the co... more We performed systematic experiments on the synthesis of layered crystal α-ZrP and revealed the control of size, aspect ratio and size polydispersity of disk-shaped crystals. The growth of the disks is mediated by oriented attachment, taking place continuously throughout the hydrothermal treatment between various sized disks. The master of the synthesis of layered crystals will contribute to various applications such as the nanocomposites and liquid crystals.
Industrial & Engineering Chemistry Research, 2014
The influence of size and crystallinity on the efficiency of dust explosion inhibition was system... more The influence of size and crystallinity on the efficiency of dust explosion inhibition was systematically studied. We fractionated ammonium phosphate monobasic (MAP, NH 4 H 2 PO 4) and dibasic (DAP, (NH 4) 2 HPO 4) at different size ranges, and we synthesized zirconium phosphate (α-ZrP, Zr(HPO 4) 2 •H 2 O) at varying sizes and crystalline levels. To evaluate the inhibitor efficiency of each material, we analyzed the thermal stability of mixtures containing cornstarch and DAP/α-ZrP/MAP, using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). In addition, the dust explosion severity (i.e., maximum pressure (P max) and maximum rate of pressure rise ((dP/dt) max)) of these mixtures was obtained by performing dust explosion tests using a 36 L vessel. The experimental results show that α-ZrP provides the highest thermal stability but the lowest rate of heat absorption of the mixtures. DAP exhibited a lower thermal stability in comparison to α-ZrP and MAP, but exhibits a remarkable rate of energy absorption during its decomposition reaction. In general, the efficiency of dust inhibitors increased by decreasing particle size. Particularly, DAP and MAP presented a critical diameter (i.e., 128 μm), where the inhibitor efficiency was enhanced. However, the performance of α-ZrP as an inhibitor was not considerably affected by the variation of particle size and crystalline level. Finally, a semiempirical model was developed to identify the factors dominating the reduction of cornstarch explosion severity. In agreement with aforementioned results, the simplified model presents a critical diameter below which the inhibitor efficiency is significantly improved.
Proceedings of the CUBE International Information Technology Conference on - CUBE '12, 2012
Soft Matter, 2013
ABSTRACT We developed Pickering foams highly stabilized by high-aspect-ratio (ξ = diameter/thickn... more ABSTRACT We developed Pickering foams highly stabilized by high-aspect-ratio (ξ = diameter/thickness) nano-sheets. The effects of particle aspect ratio, concentration, and hydrophobicity were also investigated. To our knowledge, our study provides the first experimental evidence of the effect of particle aspect ratio on particle-stabilized foams. The adsorption properties of these highly anisotropic nano-sheets are strongly affected by their small thickness and large lateral size (i.e., two-dimensional). These high-aspect-ratio nano-sheets were obtained by exfoliation of α-zirconium phosphate (ZrP) crystals with propylamine (C3H7NH2, PA). The hydrophobicity of the nano-sheets was tailored by adjusting the PA:ZrP molar ratio in the suspension. The morphology and stability of the foam depend on the nano-sheet aspect ratio and concentration as well as on the PA:ZrP molar ratio. Here, we found that using low and high aspect ratio nano-sheets having a high and an intermediate degree of hydrophobicity, respectively, is the successful formula to obtain high foam stability. The aqueous foams were characterized by optical and cross-polarized micrographs. Scanning electron microscopy (SEM) micrographs of dried foams revealed the adsorption of the PA–ZrP nano-sheets on the air–water interface. The foam stability was studied by measuring the foam and the water volume as a function of time to obtain the foam decay and water drainage rate, respectively. We also observed that the foams were stabilized by jammed layers of nano-sheets located in the bulk and at the air–water interface. These layers of particles prevent air diffusion between the bubbles, hence arresting Ostwald ripening and coalescence.
Soft Matter, 2012
Supporting Information 1. Particle-stabilized emulsions Adsorption of homogeneous and amphiphilic... more Supporting Information 1. Particle-stabilized emulsions Adsorption of homogeneous and amphiphilic particles at liquid-liquid interfaces Fig. S1. Illustrations of (a) a disk-shaped Janus particle and (b) its interfacial adsorption. Modified according to Nonomura et al. 1 Using homogeneous spheres, the highest stability of the resulting Pickering emulsion occurs when the three-phase contact angle among the particle, hydrophobic, and hydrophilic fluids is around 90º. 2-7 Hydrophobic particles will stabilize water-in-oil emulsions having a contact angle slightly greater than 90°, whereas hydrophilic particles will
Powder Technology, 2014
ABSTRACT This paper reports experimental results elucidating the effect of particle size polydisp... more ABSTRACT This paper reports experimental results elucidating the effect of particle size polydispersity (sigma(D)) on the explosion severity of aluminum dust. Five mixtures with a median diameter (D-50) of 15 mu m and sigma(D) values of 0.95, 1.17, 1.48, 1.87, and 2.51, were systematically prepared by mixing original aluminum samples having narrow size distributions. The explosion severity of each sample was determined in a 36 L dust explosion vessel by measuring the maximum pressure (P-max), the maximum rate of pressure rise ((dP/dt)(max)), and the deflagration index (K-St). Interestingly, we found that values of P-max and K-St revealed an increase in explosion severity as sigma(D) increases, where the latter presented a more dramatic effect due to the contribution of fine particles on the combustion kinetics. The effect of dust concentration on the explosion propagation was analyzed comparing the time span to reach (dP/dt)(max), (tau), during a dust explosion. tau was obtained from the experimental pressure traces of the original samples and their mixtures. The values of P-max and K-St, were plotted as a function of the median diameter (D-50) and the volume-(D-4,D-3) and surface-(D-3,D-2) weighted mean diameter. We observed that D-3,D-2 provided a better description of the average sample size and D-50 is inadequately related to the real hazard potential of aluminum dust. Therefore, we suggest that the explosion hazard characterization of these types of materials should be reported in terms of D-3,D-2 and sigma(D).
Physical Review Letters, 2012
Phase behavior of charged disk suspensions displays strong dependence on ionic strengths, as the ... more Phase behavior of charged disk suspensions displays strong dependence on ionic strengths, as the interplay between excluded volume and electrostatic interactions determines the formation of glasses, gels, and liquid crystal states. The various ions in natural soil or brine, however, could present additional effects, especially considering most platelet structures bear momentous ionexchange capacity. Here we observed how ion exchange modulates and controls the interaction between individual disks and leads to unconventional phase transitions from isotropic gel to nematic gel, and finally to nematic liquid crystals.
Physical Review E, 2012
We demonstrate the strong dependency of the IN transition of discotic suspensions on the aspect r... more We demonstrate the strong dependency of the IN transition of discotic suspensions on the aspect ratio (ξ = thickness/diameter) via control of the sizes of pristine ZrP crystals and subsequent exfoliation to monolayers. The size-fractionation of the IN transition facilitates the analysis of the effect of polydispersity. A systematic variation of the aspect ratio in the low aspect ratio region (0.001 < ξ < 0.01) showed that the IN transition volume fraction increases with aspect ratio in agreement with computer simulations. It was found that the transition volume fractions scale with aspect ratio φ I,N =mξ 1.36 ± 0.07 , where the prefactor m strongly depends on size polydispersity for φ N , but does not depend on size polydispersity for φ I , with φ I and φ N being the volume fractions of the isotropic and the nematic phases on the cloud curves, respectively.
Obesity Surgery, 2007
Bariatric surgery, mainly laparoscopic Roux-en-Y gastric bypass, is widely considered to be the b... more Bariatric surgery, mainly laparoscopic Roux-en-Y gastric bypass, is widely considered to be the best operation for the treatment of morbid obesity. Leak or fistula of the gastrojejunostomy is a feared complication of this procedure. A patient who developed a gastrocutaneous fistula and was successfully managed endoscopically is reported.