Methylene Blue Test Research Articles

KARAKTERISTIK ZONASI BATUAN RESERVOAR BERDASARKAN PETROGRAFI, SERBUK BOR, UJI TEKANAN DAN TEMPERATUR DI LAPANGAN PANAS BUMI SOKORIA, KABUPATEN ENDE, PROVINSI NUSA TENGGARA TIMUR

Lapangan Panas Bumi Sokoria terletak di Desa Sokoria, Kabupaten Ende, Provinsi Nusa Tenggara Timur. Penelitian ini bertujuan untuk mengetahui karakteristik zonasi secara vertikal batuan penudung, transisi dan reservoar pada sumur W-1 dan W-2. Pendekatan yang digunakan adalah analisis petrografi dan analisis metilen biru (MeB) untuk mengetahui rasio ilit-smektit dan kehadiran mineral alterasi dalam batuan sebagai indikator batas zona batuan penudung, transisi dan reservoar. Uji tekanan dan temperatur (P&T Test) juga digunakan sebagai panduan dalam penentuan zonasi. Hasil yang didapat bahwa zona penudung panas bumi berada dari permukaan hingga kedalaman 700 mVD (meter vertical depth), dibuktikan oleh indeks MeB sedang – tinggi (20 – 80%) penciri smektit serta temperatur batuan sekitar 100°C. Zona transisi berada dari kedalaman 700 mVD – 1100 mVD, dibuktikan oleh indeks MeB rendah (6 – 20%) sebagai penciri ilit dan ilit-smektit serta temperatur uji mencapai 200°C. Zona reservoar berada pada kedalaman 1100 mVD, dicirikan oleh indeks MeB sangat rendah (<10 %) sebagai penciri ilit serta kemunculan epidot pada sumur W-1 di kedalaman 1119 mMD (meter measured depth) dan sumur W-2 di kedalaman 1338 mMD, uji P&T menunjukkan temperatur reservoar dapat mencapai 250°C.

Switchable Pickering emulsions stabilized by polystyrene-modified magnetic nanoparticles

Switchable Pickering emulsions were prepared using polystyrene-modified magnetic nanoparticles (PS-MNPs) as stabilizers in mixtures consisted of a polar solvent, such as chloroform, and water. For this purpose, bare magnetic nanoparticles (bMNPs) were firstly synthesized but they were not able to stabilize emulsions prepared with chloroform. Consequently, the surface of the bMNPs was modified with polystyrene via radical polymerization to provide the nanoparticles more hydrophobic character. This resulted in stable water-in-oil (W/O) and oil-in-water (O/W) Pickering emulsions from water/chloroform mixtures. Variables affecting the coating step, including reaction time and amount of styrene in the polymerization mixture, were studied. The resulting material was characterized in terms of composition and size by infrared spectroscopy (IR-ATR), transmission microscopy (TEM) and dynamic light scattering (DLS). Next, different percentages of aqueous and oil phases were tested obtaining switchable W/O and O/W Pickering emulsions, depending on the percentages of each phase. To demonstrate what type of emulsion was formed with each percentage, the emulsions were observed under the optical microscope and both the drop and the methylene blue tests were performed. Finally, to evaluate the stability and morphology of the Pickering emulsions obtained by the PS-MNPs, the effect of the temperature, pH value and salt was also investigated in detail.

The role of Intraoperative cholangiography (IOC) and methylene blue tests in reducing bile leakage after living donor hepatectomy

AimLiver transplantation remains the only curative treatment in end stage liver disease. Biliary complications remain the most common major morbidity causes in hepatic resection. We aimed to determine and eliminate the bile leakage in donor hepatectomy of LDLT. Material and methodsThis study was conducted retrospective and one center study. The study population included 110 consequential liver donors with major liver resection (more than three segments). The population was divided into three groups for data analyses. Primary study groups included 40 donors subjected to methylene blue test starting in April 2013 and 40 donors subjected to intraoperative cholangiography started in March 2014. ResultsA total of 110 liver donors (42.7% women) were included in the study. Postoperative biliary complications were less in methylene blue and intraoperative cholangiography (IOC) groups. Bile leakage was significantly higher in control group (23.3%) compared to methylene blue (5%) and IOC groups (2%) Average duration of hospital stay and duration of operation were significantly higher in control group compared to methylene blue and IOC groups. ConclusionIn our study we conducted to establish biliary leakage in living donor hepatectomy which intraoperative cholangiography test was used to determine. Many intraoperative methods have been introduced to prevent biliary leakage and development of complications. We have showed that IOC test used in the present study could be easily applied in both living liver donor hepatectomy and other major hepatectomy cases. IOC test reduced postoperative biliary leakage incidence and did not increase incidence of other complications.

Computer vision based Comparative Studies on the Physicochemical Analysis and Bacterial Biota in Different Milk Samples

Milk is a complete food with high nutritional value. Milk is an important culture medium for the growth and reproduction of microorganisms. This study focuses on the samples collected from the different milk distribution areas in MaduranthagamTaluk, South India. Fifty pasteurized milk samples of ten different brands were collected and physicochemical, microbiological analysis were carried out in both raw milk and pasteurized milk samples. The milk samples were subjected to physicochemical analysis such as Fat content, Clearance, Lactometric Reading, Clot on Boiling Test, Solid Non Fat and Acidity were calculated. The milk sample were also subjected to the chemical analysis for the Nitrogen content, crude protein content, Lactose content, ash content were also calculated Methylene blue reduction test has been used to test quality of the milk samples. These findings may be helpful to monitor the quality of the milk products in the market. It can provide an interest in examine the organic and inorganic content in milk. It is reported that all samples added with urea and few samples have sulphate. Raw milk showed inferior quality, processed milk have Low load of bacterial population.

Detection of lactoferrin in bovine and goat milk by enzyme-linked immunosorbent assay

Lactoferrin (LF) has been proposed as a multifaceted functional ingredient of food. A competitive enzyme-linked immunosorbent assay (ELISA) was established to determine the LF in milk by using bovine LF antiserum and bovine LF-Biotin conjugate. The LF concentration in cow milk samples could be determined by this ELISA. However, the LF concentration in goat milk could not be measured using this method. Thus, the goat LF ELISA was established using goat LF-Biotin conjugate to measure the LF concentration in goat milk. Milk samples were collected for measurement of their LF concentrations. The mean LF level for the individual cow milk samples with the somatic cell count (SCC) below 1 × 105, 1 to 2.5 × 105 or 2.5 × 105 to 5 × 105 cells/mL was found to be about 176, 466 or 742 μg/mL, respectively. On the other hand, the LF level was about 200 μg/mL in goat bulk milks with the methylene blue reduction test (MBRT) time more than 5 hr. In conclusion, both LF ELISA methods developed in this study could be successfully used to determine the LF concentration in goat and cow milk.

Chemical modification of lignin derived from spent coffee grounds for methylene blue adsorption

In this work, spent coffee grounds (SCG) were treated using sulfuric acid hydrolysis in order to isolate the sulfuric acid lignin (SAL). The reactivity of SAL was improved through phenolation and acetylation. Spectroscopic analysis showed that the isolated lignin is composed of GHS type and it was characterized by a high amount of (C–C) and β-O-4 bonds. The thermal analysis showed that the phenolated sulfuric acid lignin (Ph-SAL) present higher thermal stability compared to SAL and acetylated sulfuric acid lignin. In addition, the phenolic hydroxyl group content increases from 2.99 to 9.49 mmol/g after phenolation. Moreover, a methylene blue (MB) adsorption test was established in order to find out the sorption capacity of different samples. The study showed that the adsorbed amount of dye increase after the chemical modification of SAL, especially after phenolation. The removal efficiency was enhanced after modification to reach 99.62% for Ph-SAL. The evaluation of the adsorption experimental data with the theoretical models of Langmuir and Freundlich showed that the best fitting was expressed by the Langmuir model for all samples. Finally, this study showed that lignin isolated from SCG can be simply and easily chemical modified and exhibits excellent adsorption ability towards cationic dyes (MB) in aqueous solutions. As a renewable, low-cost, and natural biomass material, lignin from SCG shows a promising practical and economical application of biomass in the field of wastewater purification.

Research application of K2CO3 activated coal coal and processing by HNO3 from cake shoulder to process Methylene Blue color

Macadamia is a tree that produces dried fruits, with each ton of macadamia seeds producing 70 - 77% of the shell. Annually, the grain processing companies in Vietnam produce thousands of tons of seeds and release tens of thousands of tons of shells. As the demand for macadamia nuts is constantly increasing in the market, more in-depth studies are needed to handle this agricultural residue. Macadamia shell has a higher surface area than other seed pods and their ash content is very low at only 0.22%, the cellulose content in the shell is about 41.2%, this shows that Macadamia shell has the potential to prepare activated carbon when burning at high temperatures. The activated carbon surface can be modified appropriately to change adsorption characteristics, forming different types of surface functional groups (oxygen functional groups, carbon surface functional groups, carbon functional groups, carbon - nitrogen, carbon - halogen) and make coal more suitable for special applications. Results of researching to prepare bio-denatured material from activated carbon K2CO3 by chemical method using HNO3 agent with optimal denaturing conditions such as concentration of 21%, denaturation time of 12 hours, degree MB adsorption reached 193.13 mg/g. The results of methylene blue adsorption adsorption tests at the optimal conditions show that at pH = 9.5 with the appropriate dose of coal is 1g/L in 120 minutes, it can be processed to reach 79.36% efficiency for water. Methylene Blue waste is 70 mg/L.

A Knowledge-Based System for Fine Aggregate Material Problem Selection in Concrete Production

One of the main problems of our country is inability to select the right materials of high quality in production. Decision making based on multiple criteria has an important role to do the right selections in each sector. One of these sectors is construction. Construction sector develops rapidly and using the right material is an important issue. Using the right material in this period when construction sector develops rapidly has a great importance. In the construction sector, the building material which has been used the most widely from past to present is concrete. In this study, a knowledge-based system via TOPSIS approach was proposed to generalize the multi-criteria decision making problems of fine aggregate material selection in concrete production. In addition, six different mortar series were produced by using the fine aggregates which were obtained from various plants used in the production of ready-mixed concrete in Kütahya and CEN Standard sand. The methylene blue, physical and mechanical tests were carried out on the produced mortars in order to get an idea for the strength and durability of concrete. The purpose of the study was to determine which of the five different fine aggregates had characteristics that are the closest to those of CEN Standard sand based on defined these multi criteria. It was found that the best fine aggregate series was A based on the defined criteria by considering the results of the experiments, assigning weights based on importance and analyzing these with TOPSIS approach.

Is it possible to predict the microbiological quality of goat milk by physicochemical parameters?

This study evaluated the impact of microbial growth (at 7 and 25 °C) on methylene blue and resazurin reduction and on the physicochemical parameters of goat milk. It was also evaluated the impact of milk freezing-thawing on these same parameters. The Lactobacillus (Lb) showed the highest growth rate and the time required for total bacteria count (TBC) to reach the limit recommended by Brazilian and European legislation was 4 and 5 days at 7 °C and 7 and 8.4 h at 25 °C, respectively. In addition, boiling instability was observed after 22 h at 25 °C (TBC = 1.9•1010 CFU mL−1), showing high thermal stability. Among the studied physicochemical parameters, only the methylene blue and resazurin tests showed significant changes (reduction from ~11 to 10h to ~7-6h) when TBC reached the limit of Brazilian legislation. For the limit of European legislation, dye reduction tests showed a reduction of 60%, while only slight changes (<20%) were observed for the other evaluated parameters. For frozen milk, no difference in the physicochemical parameters were observed after thawing, although an increase in Lb count (~0.8 log) was found at 7 °C. The results indicated that the dye reduction test, especially resazurin, was the best option to indirectly assess the quality of goat milk.

Endourological Management of Iatrogenic Ureterovaginal Fistula following Obstetric and Gynecological Surgeries at Tertiary Referral Center

Aims: To evaluate the outcome of endourological management of iatrogenic ureterovaginal fistula caused by gynecological and obstetric surgeries.&#x0D; Methods: This is a retrospective analysis of uretorovaginal fistula (UVF) patients who underwent UVF management with endourology technique from February 2014 to November 2019. All data were taken from fistula database. All non-obstetric/gynaecological cases and open surgical procedures leading to UVF were excluded. Diagnostic evaluation by cystoscopy and ureterorenoscopy; and use of guide wire, C-arm and DJ stent were recorded. Three to six months post-operative follow up status was also recorded.&#x0D; Results: There were 14 cases managed by retrograde DJ stenting. Both hysterectomy (n=10) and Cesarean Sections (n=4) were the past surgeries. Diagnosis was made by history, methylene blue test, cystoscopy, intravenous urography and CT urogram. Treatment was retrograde DJ stenting. All of them had unilateral distal ureteric injury close to vesicoureteric junction leading to ureterovaginal fistula. All were continent at the end.&#x0D; Conclusions: Endourological approach with retrograde DJ stenting had successful outcome in iatrogenic UVF.&#x0D; Keywords: double J stent, endourological technique, iatrogenic ureterovaginal fistula, ureterorenoscope.

Observações clínicas, hematologia e características do fluido ruminal de bovinos de corte recebendo dieta "Max Beef" grão inteiro

Este estudo propôs caracterizar os efeitos da alimentação baseada na dieta do grão de milho inteiro na dinâmica de parâmetros clínicos e metabólitos bioquímicos de bovinos confinados. Foram utilizados 20 bovinos, sem raça definida, adultos, com peso médio de 300 kg, divididos em dois grupos experimentais. O grupo experimental (G1; n=15), composto por animais alimentado somente dieta “Max Beef” Grão Inteiro e o grupo controle (G2; n=5), composto por animais, alimentado com bagaço de cana e a dieta “Max Beef” Grão Inteiro, na proporção 30:70. Todos os animais foram submetidos às observações clínicas, colheita de sangue por venopunção jugular e fluido ruminal. Os animais do grupo G1 (Dieta “Max Beef” Grão Inteiro) apresentaram movimentos ruminais incompletos, timpania ruminal branda e diarreia com grãos de milho inteiro. Não foram registradas alterações hematológicas nem na concentração de fibrinogênio. Apresentaram menor valor de pH ruminal durante todo o período experimental, com comprometimento da população de infusórios, diminuição da prova de redução do azul de metileno e tempo de sedimentação e flotação ausente. Conclui-se que dietas para bovinos de corte contendo “Max Beef” Grão Inteiro provoca acidose crônica ruminal e compromete as características físico-químicas e microbiológicas do fluido ruminal.

Alaşehir (Manisa) Bölgesi Traverten Atıklarının Yol Alttemel ve Temel Tabakalarında Kullanılabilirliğinin Araştırılması

In this study, physical and mechanical properties of travertine wastes in Alasehir (Manisa) region were determined and their usability as sub-base and base material was investigated. Within the scope of the research, experiments related to the sub-base and base material properties in the Technical Specifications of Highways (TSH) 2013 were applied to the travertine wastes. These experiments; sieve analysis, weather resistance test with MgSO4, Los Angeles abrasion test, flatness index test, water absorption test in coarse and fine aggregate, liquid limit and plastic limit test, organic material test with NaOH, methylene blue test, clay pellet and dispersible grain ratio test, proctor and CBR experiments. In addition, the unit kilometer transportation cost of travertine waste material was calculated and the effective usable distance was calculated in terms of cost compared to crushed stone material. After all; it is seen that travertine wastes can be used as subbase and base material by meeting TSH 2013 standards. In addition, it is considered that unless a price is paid for the wastes, it is cost effective up to a certain distance and that the use of wastes in the road superstructure will reduce the harmful effects of the quarries to the environment to some extent and thus contribute to the national economy and natural balance.

Preparation and photocatalytic activity of g-C3N4/TiO2 heterojunctions under solar light illumination

The solar light sensitive g-C3N4/TiO2 heterojunction photocatalysts containing 20, 50, 80, and 90 wt% graphitic carbon nitride (g-C3N4) were prepared by growing Titania (TiO2) nanoparticles on the surfaces of g-C3N4 particles via one step hydrothermal process. The hydrothermal reactions were allowed to take place at 110 °C at autogenous pressure for 1 h. Raman spectroscopy analyses confirmed that an interface developed between the surfaces of TiO2 and g-C3N4 nanoparticles. The photocatalyst containing 80 wt% g-C3N4 was subsequently heat treated 1 h at temperatures between 350 and 500 °C to improve the photocatalytic efficiency. Structural and optical properties of the prepared g-C3N4/TiO2 heterojunction nanocomposites were compared with those of the pristine TiO2 and pristine g-C3N4 powders. Photocatalytic activity of all the nanocomposites and the pristine TiO2 and g-C3N4 powders were assessed by the Methylene Blue (MB) degradation test under solar light illumination. g-C3N4/TiO2 heterojunction photocatalysts exhibited better photocatalytic activity for the degradation of MB than both pristine TiO2 and g-C3N4. The photocatalytic efficiency of the g-C3N4/TiO2 heterojunction photocatalyst heat treated at 400 °C for 1 h is 1.45 times better than that of the pristine TiO2 powder, 2.20 times better than that of the pristine g-C3N4 powder, and 1.24 times better than that of the commercially available TiO2 powder (Degussa P25). The improvement in photocatalytic efficiency was related to i) the generation of reactive oxidation species induced by photogenerated electrons, ii) the reduced recombination rate for electron-hole pairs, and iii) large specific surface area.

Air Pollution and Nasal Mucociliary Clearance Time among Urban and Rural Residents in Two Philippine Communities

ABSTRACT&#x0D; Objective: To measure the nasal mucociliary clearance (NMC) time among adults residing in two Philippine communities with different air quality indices using the saccharin and methylene blue test.&#x0D; Methods:&#x0D; Design: Cross-Sectional Study&#x0D; Setting: Diliman, Quezon City and Puerto Princesa, Palawan&#x0D; Participantss: Fifty (50) participants, 25 residing in an urban city with fair air quality index and 25 residing in a rural province with good air quality index.&#x0D; Results: The mean NMC time of the urban group was 22.15±12.68 mins and was significantly longer than the NMC time of the rural group which was 5.29±2.87mins; t(48) = 6.643, p&lt;0.0001).&#x0D; Conclusion: Increased air pollution may be associated with significant prolongation of nasal mucociliary clearance time among urban residents with fair quality air index compared to rural residents with good quality air index.&#x0D; Keywords: nasal mucociliary clearance, naso mucociliary clearance time, air pollution, air quality index, saccharin test, methylene blue

Synthesis OF AG/TIO2 nanocomposite via plasma liquid interactions and degradation methylene blue

A novel method employing atmospheric pressure discharge plasma has been developed to reduce supported Ag nanoparticles (Ag NPs) and deposited on TiO2 powder without the use of any environmentally and biologically hazardous reducing chemicals. Ag/TiO2 nanocomposite was prepared by the atmospheric direct current plasma in water solution. Trisodium citrate and CMC was used as a capping agent for Ag nanoparticles. The nanocomposites were characterized using UV–Vis spectroscopy, X-ray diffraction, scanning electron microscopy. The results showed that Ag NPs with an average diameter of 20–35.5 nm were uniformly distributed on the powders surface. The presence of nanosilver particles in TiO2 matrix is clearly visible. The bandgap of TiO2/Ag was confirmed (2.65–2.85 eV) through UV–vis DRS, which was lower than TiO2 (3.8 eV). The photocatalytic effect was conducted by methylene blue degradation test. The photocatalytic activity of a series of 2 wt. % Ag/TiO2 composites was evaluated in the degradation of MB (used as a model pollutant) in aqueous solution under solar light. The 2.0 mol % of Ag-doped TiO2 shows 96% degradation of methylene blue (MB) within 50 min under visible light irradiation and exhibit highest photocatalytic performance.

Highly efficient photocatalytic methylene blue degradation over Sn(O,S)/TiO2 photocatalyst fabricated via powder atomic layer deposition of SnO and subsequent sulfurization

In this work, tin oxysulfide coated TiO2 nanoparticles for photocatalytic pollutant degradation were fabricated via a two-step vacuum process which involves powder atomic layer deposition (PALD) of SnO on TiO2 nanoparticles followed by sulfurization annealing. The physical and chemical properties of the Sn(O,S)/TiO2 nanoparticles were characterized and compared with TiO2 and SnO/TiO2. From the methylene blue (MB) degradation test, the photocatalytic activities of Sn(O,S)/TiO2 were examined. The Sn(O,S)/TiO2 showed ~ 6.7 and 16-fold improved MB degradation rate constants of 0.002 and 0.114 min−1 compared to the pristine TiO2 under visible light and Xe lamp irradiations, respectively. This may be attributed to the synergetic effects of enhancing the electron-hole charge separation and light absorption characteristics.

Identification of Two Pathogens in a Culture‐Negative Prosthetic Joint Infection Using Nanopore Sequencing

Periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) is challenging to diagnose due to lower yield in pathogenic identification (~50%) using conventional microbiologic culture techniques. Here we present a case in which two pathogens were detected using nanopore sequencing from a 50 year‐old male with a suspected, yet culture‐negative, PJI. Three swabs were taken from multiple sites of drainage surrounding the suspected infected right knee joint following a routine arthroplasty (original TKA was done three years prior). DNA was extracted from the swabs using the MasterPure™ Gram Positive DNA Purification Kit (Lucigen). Sample libraries were prepared using the Rapid PCR Barcoding Kit (Oxford Nanopore Technologies) and sequenced on a v9.4.1 MinION flow cell. A total of 1,056,710 reads from all three swabs combined were aligned using a minimum Q score of 7.0 to the RefSeq database on the EPI2ME platform using the “What’s in my pot?” app. A total of 5,540 reads (0.52%) aligned to the bacteria Corynebacterium with the most abundant species being detected as Corynebacterium simulans. A total of 1,886 (0.18%) mapped to the fungi Malassezia globosa. Due to the patient having a visible arthrocutaneous fistula combined with visualized drainage from the joint using a methylene blue challenge test, the prosthetic knee was removed and an antibiotic spacer that contained 6 gm vancomycin, 7.2 gm tobramycin and 100 mg of amphotericin B was implanted. The patient also received a 6 week course of ceftriaxone infusions and has shown rapid clinical improvement. While our sequencing results were not used directly for patient care in this case, it demonstrates the promise that nanopore sequencing has for future use in infectious disease diagnostics.

Thermo-oxidative Reactivation of Active Coal Used in Streptomycin Production

The spent active coal of streptomycin production contains on its surface the remains of inorganic acids, organic-originated alcohols and waste products, spores, mycelium of Streptomyces griseus, which after entering the environment with wastewater cause a significant harm to it. The recycling of that coal and its reuse betters the economics of production and prevents harmful impurities from entering the environment together with that coal. Here it is demonstrated that thermal heating up to 300 °C allows to increase the adsorption activity according to methylene blue test and pH of aqueous extract of recycled sorbents close to the regulatory values, which raises the possibility of their re-use in the production of streptomycin. The raise of temperature more than 300 °C leads to decomposition of high-molecular organic substances on the surface of a coal with subsequent formation of a carbon film which covers the adsorbing pores and worsens the adsorption properties of active coal. After treatment with water vapor at a temperature of 800 °C the characteristics of the active coal meet the regulatory requirements of streptomycin production. Rational way to dispose an active coal which lost its recyclability is a burning at temperatures more than 800 °C. This completely neutralizes all the harmful impurities.

Does the Methylene Blue Test Give Equally Satisfactory Results in All Studied Igneous Rocks Relative to the Identification of Swelling Clay Minerals?

The presence or the absence of swelling clay minerals in rocks, which are used in various construction applications, constitutes a determinant factor for their strength, and consequently, in their general behavior in various construction applications, as they have the ability to swell up to 400 times of their usual volume, causing failures to any application in which they participate. The aim of this study is to respond to the question of whether the empirical method of methylene blue yields equally safe and correct results in different types of igneous rocks and if not, which is the determining factor affecting the results. The answer to this complex question is feasible by investigating the microscopic structure and the mineralogy of the studied rocks, and particularly, using the content of specific phyllosilicate minerals which may be related or not with the methylene blue values. According to the results, the methylene blue test seems to work correctly for the intermediate (Group I) and mafic (Group II) examined rocks, but it seems to be wrong for the highly serpentinized ultramafic rocks (up to 70% of serpentine) (Group III).

Bariatrik cerrahide rutin intraoperatif ve postoperatif kaçak testlerine ihtiyaç var mı?

Aim: We aimed to evaluate the efficacy of the results of intraoperative methylene blue test and postoperative upper gastrointestinal contrast graphies for detecting leakage in both primary and revisional bariatric surgery. Methods: Two-hundred-eighty-seven patients, who underwent primary and revision bariatric surgery and routine intraoperative methylene blue test and upper gastrointestinal contrast studies postoperatively for leakage were included in the study. Patients’ demographic characteristics, comorbidities, length of hospital stay, operation time, intraoperative, and postoperative complications were analyzed retrospectively. Results: In our study, 256 of 287 (89.1%) patients underwent primary surgery, 221 (75.7%) patients were female, the mean patient age was 38.4 ± 11.9 years, and the mean body mass index was 44.3 ± 7.6 kg/m2. The number of patients who had previous abdominal surgery and comorbidity was 108 (37.6%) and 149 (51.9%), respectively. Leakage was detected by a methylene blue test in one (0.3%) patient who underwent one-anastomosis gastric bypass surgery. In one (3.2%) patient who underwent revisional surgery with negative results of methylene blue test, leakage was detected on the first postoperative day due to the clinical findings. There was no leakage detected in any patient with postoperative swallow graphies. There was no statistical difference in leakage between primary and revisional surgery groups (p = 0.23). There was no mortality. Conclusion: It could be unnecessary to use postoperative gastrointestinal contrast studies in both primary and revisional bariatric surgery, but the routine use of the intraoperative methylene blue test could be considered useful due to its positive results for the detection of leakage.