Novel adsorbent for malachite green from okra stalks waste: synthesis, kinetics and equilibrium studies.

In this study, malachite green (MG) removal was performed with activated carbon synthesized from okra stalks by microwave assisted chemical activation method. In the synthesis of activated carbon, the effects of gas in the microwave, activation, and impregnation rate were investigated. The synthesized activated carbon characterization was investigated using BET, FT-IR, and SEM analyses. The activated carbon surface area achieved was 759.453 m2 g-1. In addition, the surface area of activated carbon synthesized using the conventional method was17.766 m2 g-1. The effect of the initial solution concentration on MG adsorption was investigated. According to the kinetic and equilibrium data, it was found that the adsorption process best fitted the pseudo-second order kinetic model and the Langmuir isotherm. According to the equilibrium data, the maximum adsorption capacity (qmax) of the monolayer was 119.05 mg g-1. In addition, MG adsorption was investigated by the experimental design method. The adsorption capacity at the determined optimum conditions was 99.63 mg g-1. All results show that activated carbon synthesized from waste biomass by combining the conventional method with microwave-assisted impregnation is a cheap and environmentally friendly adsorbent.

The synthesis of activated carbon from waste biomass using the conventional activation method is quite common. Activated carbon synthesis studies have increased in recent years with microwave-assisted impregnation, which has been integrated into the conventional activation method. Using this new method, the synthesis of activated carbon from okra stalk waste was carried out for the first time in this study. In addition, with this novel adsorbent, malachite green was removed from the aqueous solutions for the first time.

Asymptomatic synthetic vascular graft migration to duodenum after living donor liver transplantation: report of two cases.

BACKGROUND: In this study, we present the results of two patients with vascular graft migration to the duodenum after liver transplantation. METHODS: The results of two patients who underwent living donor liver transplantation and vascular graft to the duodenum were evaluated. RESULTS: In our center, 201 liver transplants were performed, including 154 a right lobe living donor liver transplant. A synthetic graft was used to reconstruct segment 5 and 8 hepatic veins in 78 of the 154 LDLT. During the mean follow-up 19.6 ± 12.1 months (1-44 months), graft migrated to the duodenum in two patients who were present in this study. Contrary to the literature, it was followed nonoperatively. No problem was observed in the follow-up process. CONCLUSION: In patients with vascular graft migration to the duodenum after living liver transplantation, non-operative follow-up can be performed in appropriate patients.

Outer-Membrane Protease (OmpT) Based E. coli Sensing with Anionic Polythiophene and Unlabeled Peptide Substrate.

E. coli and Salmonella are two of the most common bacterial pathogens involved in foodborne and waterborne related deaths. Hence, it is critical to develop rapid and sensitive detection strategies for near-outbreak applications. Reported is a simple and specific assay to detect as low as 1 CFU mL-1 of E. coli in water within 6 hours by targeting the bacteria's surface protease activity. The assay relies on polythiophene acetic acid (PTAA) as an optical reporter and a short unlabeled peptide (LL37FRRV ) previously optimized as a substrate for OmpT, an outer-membrane protease on E. coli. LL37FRRV interacts with PTAA to enhance its fluorescence while also inducing the formation of a helical PTAA-LL37FRRV construct, as confirmed by circular dichroism. However, in the presence of E. coli LL37FRRV is cleaved and can no longer affect the conformations and optical properties of PTAA. This ability to distinguish between an intact and cleaved peptide was investigated in detail using LL37FRRV sequence variants.

Taguchi DoE methodology for modeling of synthetic dye biosorption from aqueous effluents: parametric and phenomenological studies.

Biosorption technology has been acknowledged as one of the most successful treatment approaches for colored industrial effluents. The problems such as its high manufacturing cost and poor regeneration capability in the use of activated carbon as a biosorbent have prompted the environmental scientists to develop alternative biosorbent materials. In this context, as a sustainable green generation alternative biosorbent source, the discarded seed biomass from pepper (Capsicum annuum L.) processing industry was explored for the biotreatment of colored aqueous effluents in this study. To test the wastewater cleaning ability of biosorbent, Basic red 46 was selected as a typical model synthetic dye. Taguchi DoE methodology was employed to study the effect of important operational parameters, contact time, pH and synthetic dye concentration, on the biosorption process and to develop a mathematical model for the estimation of biosorption potential of biosorbent. The percentage contribution of each of these process variables on the dye biosorption was found to be 19.31%, 41.39%, and 38.74%, respectively. The biosorption capacity under the optimum environmental conditions, contact time of 360 min, pH of 8 and dye concentration of 30 mg L-1, was estimated to be 92.878 mg g-1 (R2: 99.45). This value was very close to the experimentally obtained dye removal performance value (92.095 mg g-1). These findings indicated the high ability of Taguchi DoE technique in the optimization and simulation of dye biosorption system. The kinetic and equilibrium modeling studies showed that the pseudo-second-order and Langmuir models were the best models for the elucidation of dye removal behavior of biosorbent. The thermodynamic studies displayed that the dye biosorption was a feasible, spontaneous and exothermic process. This parametric and phenomenological survey revealed that the discarded pepper seed biomass can be introduced as a potential and efficient biosorbent for the bioremediation of colored industrial effluents.

Bioremediation potential of a widespread industrial biowaste as renewable and sustainable biosorbent for synthetic dye pollution.

In this study, a model synthetic azo dye (Basic red 46) bioremoval by Carpinus betulus sawdust as inexpensive, eco-friendly, and sustainable biosorbent from aqueous solution was examined in a batch biosorption system. The effective environmental parameters on the biosorption process, such as the value of pH, amount of biosorbent, initial dye concentration and contact time were optimized using classical test design. The possible dye-biosorbent interaction was determined by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The equilibrium, thermodynamic, and kinetic studies for the biosorption of Basic red 46 onto the sawdust biomass were performed. In addition, a single-stage batch dye biosorption system was also designed. The dye biosorption yield of biosorbent was significantly influenced by the change of operating variables. The experimental data were best described by the Freundlich isotherm model and both the pseudo-first-order kinetic and the pseudo-second-order kinetic models. Thermodynamic research indicated that the biosorption of dye was feasible and spontaneous. Based on the Langmuir isotherm model, the biosorbent was found to have a maximum biosorption potential higher than many other biosorbents in the literature (264.915 mg g-1). Thus, this investigation presents a novel green option for the assessment of waste sawdust biomass as a cheap and effective biosorbent material.

Management of suspected common bile duct stone: diagnostic yield of current guidelines.

BACKGROUND: The American Society for Gastrointestinal Endoscopy (ASGE) has recently published a guideline for suspected CBDS with the intention of reducing unnecessary ERCP and thereby complications. The aim of this study was to assess the diagnostic efficacy of the ASGE guideline. METHODS: Data of patients who underwent ERCP with suspected CBDS were analyzed retrospectively. Patients were classified into high, intermediate and low risk groups based on predictors that have been suggested by the ASGE. Very strong predictors of the presence of ductal stones included: CBDS on transabdominal ultrasonography (US), clinical ascending cholangitis or total bilirubin (TBIL) >4 mg/dL). Strong predictors included dilated CBD >6 mm on US with gallbladder in situ and TBIL level of 1.8-4.0 mg/dL whereas moderate predictor included abnormal liver biochemical test other than bilirubin, age more than 55 years and clinical findings of biliary pancreatitis. RESULTS: Of 888 enrolled patients, 704 had CBDS demonstrated by ERCP and the remainder did not. All very strong and strong predictors were found to be significantly higher among patients who had CBDS. Detection of CBDS by ultrasonography and a dilated common biliary duct were observed to be independent risk factors associated with the existence of CBDS. The high risk group had a high (86.7%) positive predictive value (PPV), however, sensitivity and specificity were observed to be moderate (67.8% and 60.3% respectively). PPV was 67.9% in the intermediate risk group and the sensitivity and specificity were very low (31.9% and 42.3%). DISCUSSION: The probability of CBDS was observed to be high in the intermediate and high risk groups. However due to low sensitivity and specificity values, the ASGE guideline needs additional or different predictors.

Clinical and histological features of idiosyncratic liver injury: Dilemma in diagnosis of autoimmune hepatitis.

AIM: Drug-induced liver injury (DILI) is becoming a worldwide problem with its still unexplained properties. METHODS: The data of patients who were diagnosed with DILI between January 2008 and December 2013 were assessed. RESULTS: Five patients had been diagnosed with intrinsic and 82 patients with idiosyncratic DILI. The most common causative agents were antimicrobial drugs. The most common injury pattern was hepatocellular. When patients with bilirubin levels of more than 5 mg/dL were divided into two groups according to receiving steroid therapy (n = 11) or not (n = 40), there was not any significant difference according to their clinical results (P > 0.05). Five of the idiosyncratic DILI patients were diagnosed with drug-induced autoimmune hepatitis (DI-AIH). In histopathological examination, hepatic rosette formation and emperipolesis were observed to be more common among patients with DI-AIH when compared with ones without (P < 0.05). Interestingly, in the remaining patients with DILI (n = 77), three of them were diagnosed with classic autoimmune hepatitis during long-term follow up (range, 11-51 months). CONCLUSION: The most common causes were antimicrobials, but any agents that have not been defined to cause DILI can induce DILI. The efficacy of steroids in DILI has not been observed but all deaths were observed in the steroid-free group. The association of DILI and AIH was observed in two different types in terms of diagnosis in our study. The first association was DI-AIH. The second one is the classical AIH which developed in three patients after a few months following spontaneous recovery of DILI.

Mean platelet volume is a useful indicator of systemic inflammation in cirrhotic patients with ascitic fluid infection.

AIM: Ascitic fluid infection (AFI) consists primarily of two variants, namely, culture-negative neutrocytic ascites and spontaneous bacterial peritonitis (SBP). Mean platelet volume (MPV) has begun to be used as a simple and inexpensive indicator of inflammation in some diseases. We aimed to analyse whether platelet size alterations would be useful in predicting AFI in cirrhotic patients. MATERIAL AND METHODS: A total of 135 patients with ascites due to cirrhosis and 55 control subjects were enrolled in this study. According to ascitic fluid analysis, 58 patients were considered to have AFI. MPV and inflammatory parameter values were determined for all study participants. The ability of MPV values to predict AFI in cirrhotic patients was analysed using receiver operator characteristic (ROC) curve analysis. RESULTS: A statistically significant increase in MPV levels was observed in cirrhotic patients with AFI compared to cirrhotic patients without AFI and healthy controls (p < 0.001). A statistically significant increase was observed in the AFI group with respect to MPV, C-reactive protein (CRP) and white blood cell (WBC) levels. ROC curve analysis suggested that the optimum MPV level cut-off point for cirrhotic patients with AFI was 8.45, with a sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of 70.7%, 67.5%, 75.4% and 62.1%, respectively (area under curve: 0.768). CONCLUSION: Our study shows that MPV is increased in cirrhotic patients with AFI. MPV measurement can considered to be an accurate diagnostic test in predicting AFI, possibly due to an ongoing systemic inflammatory response.

Factors Affecting Bile Complications After Liver Transplantation: Single-Center Experience.

Objectives: In this study, we aimed to investigate the surgical technique and biochemical parameters that affect biliary complications in liver transplants from live and cadaver in our center. Methods: In this study, 141 patients who underwent liver transplants at Istanbul Yeni Yüzyil Universty Gaziosmanpasa Hospital organ transplant center between January 2018 and January 2020 were included in the study. The patients were monitored for 12-24 months. The patients included in the present study were examined retrospectively. Factors that may cause biliary tract complications and treatment modalities for complications were examined. Results: In this study, liver transplantation from 124 living donors and 17 cadavers was performed. Twenty-three patients were under the age of 18. Only seven of 39 biliary complications were operated on. The rate of finding the right graft in patients with biliary complications was higher (p<0.05). There was no statistically significant difference between the groups concerning left, left lateral, and whole graft presence (p=0.561, p=0.172, and p=0.057, respectively). Double biliary anastomosis was to be higher in the biliary complication group, but there was no statistically significant difference (p=0.086). Conclusion: Biliary complications are common, especially in liver transplants taken from the right lobe. Significant patient survival can be achieved with an early diagnosis and an appropriate treatment approach.

Association of a cylindrical polyelectrolyte brush with tetravalent counterions.

Cylindrical poly(styrene sulfonate) brushes were combined with a tetravalent double-DABCO based counterion. With increasing addition of counterion, hydrodynamic radius and radius of gyration decrease and AFMreveals a conformation change from wormlike to curled structures. Rg/Rh changes from 1.3 to 0.9. Above charge stoichiometry, brushes become interconnected into finite size assemblies, which are stable in aqueous solution for charge ratios (ratio of the molar concentration of charged counterion groups to the molar concentration of charged monomer units of the polymer brush) 1 < l < 1.2. They are compact and consist of the brushes in curled (bent) conformation, which is in difference to network-like aggregates from cylindrical poly(styrene sulfonate) brushes with tetravalent porphyrin counterions (Gröhn et al. Macromolecules 2009) and to a wormlike - bent conformation - helix transition found for another brush counterion system (Müller et al. Soft Matter 2009).

Analysis of Hepatic Arterial Reconstruction Technique Using Surgical Loupes for Living-Donor Liver Transplantation: Results From a Single Center.

BACKGROUND: The reconstruction of the hepatic artery (HA) is the most complex step in living-donor liver transplantation (LDLT) owing to the artery's smaller diameter and the increased risk for HA-related complications. In this study, we presented our HA anastomosis technique for LDLT, which employed interrupted sutures using magnifying loupes. MATERIALS AND METHODS: Since January 2019, we retrospectively analyzed 179 LDLTs that were performed at our center. HA anastomosis was performed under a loupes magnifier (2.5 or 4.5 × ) by the same surgeon. RESULTS: There were 65 female and 114 male recipients with a mean age of 41.6 ± 21.6 years. Of the recipients, 34 were children. HA thrombosis (HAT) was seen in 3 recipients (1.67%; 1 child and 2 adults) in this series. HAT occurred on the third, sixth, and seventh days after LDLT. HAT was successfully treated with interventional radiologic technique. All recipients are still alive with a patent HA. CONCLUSION: The use of magnifying surgical loupes and interrupted sutures to perform HA reconstruction is safe, feasible, and yields a low rate of HAT. Also, endovascular treatment can be used safely for treatment of HAT within the first week after LDLT with a high success rate and is not associated with major complications.

Biliary stenting in difficult common bile duct stones: a single tertiary center experience.

BACKGROUND/AIM: We aimed to examine the effect of plastic biliary stenting in the treatment of common bile duct (CBD) stones. MATERIALS AND METHODS: The data of 13,034 patients in our unit who had endoscopic retrograde cholangiopancreatography (ERCP) between 2008 and 2015 were scanned retrospectively. RESULTS: A biliary stent was placed in 61 of 74 patients. While the plastic biliary stent was placed in patients, the mean stone size after the 1st ERCP was 20 mm and the bile duct size was 13 mm. At the time of the 2nd ERCP conducted approximately 73.9 days later, the mean stone size was found to be 15 mm and the bile duct size was 12 mm. With recurrent ERCPs, the CBD stone was successfully removed in 53 patients but could not be removed in 8 patients. Among the 53 successful cases, 29 removals were successful in the 2nd ERCP session, 16 were successful in the 3rd session, 2 were successful in the 4th session, 1 was successful in the 5th session, 4 were successful in the 6th session, and 1 was successful in the 7th session. CONCLUSION: For CBD stones that cannot be removed by standard methods, temporary plastic stenting is an alternative method.

Assessment of the endoscopic retrograde cholangiopancreatography grading system: A prospective study from a tertiary care center.

BACKGROUND/AIMS: The American Society for Gastrointestinal Endoscopy (ASGE) endoscopic retrograde cholangiopancreatography (ERCP) grading system was proposed but has not been fully evaluated with prospective clinical studies. In this study, we aimed to evaluate the effectiveness of the ERCP difficulty grading system for predicting success and adverse event rates related to the procedure. MATERIALS AND METHODS: A total of 1057 ERCP procedures performed on 752 patients were included in the present study. The complexity grades of the procedures were recorded according to the ASGE grading system. Specific complications of ERCP (pancreatitis, cholangitis, bleeding, and perforation) were also defined and graded. RESULTS: The procedure difficulty was determined as 1st degree in 153 patients (14.4%), 2nd degree in 498 patients (47.1%), 3rd degree in 271 (25.6%), and 4th degree in 135 patients (12.7%). The success rate for the entire procedures was 88.4%. The success rate for 1st degree procedures was 99.3%, 97.2% for 2nd degree procedures, 86.7% for 3rd degree procedures, and 46.7% for 4th degree procedures (p<0.005). When the difficulty of the procedures increased from 1 to 4, the adverse event rates increased from 1.3% to 10.4%. CONCLUSION: The findings support the evidence that the difficulty degrees of ERCP procedures can help predict the success and complication rates of the procedure. Because of the increased rates of failure and complications in more difficult cases, the procedures should be performed by experienced endoscopists in advanced centers.

Cirrhosis with ascites: Is the presence of hemorrhagic ascites an indicator of poor prognosis?

BACKGROUND/AIMS: Hemorrhagic ascites in patients with cirrhosis is described as a RBC (Red Blood cell) > 50,000/mm³ and leads to increased morbidity and mortality. Positive red blood cells at a level of less than 50,000/mm³ (10,000-50,000) may be encountered in the ascites but it is not known whether this is clinically significant or not. This study aimed to examine the outcome of hemorrhagic ascites in patients with advanced cirrhosis. MATERIALS AND METHODS: Data from 329 cirrhotic patients with ascites who received paracentesis at least once due to ascites was retrospectively analyzed from the period of 2007-2013 from the Türkiye Yüksek Ihtisas Hospital, Department of Gastroenterology. Patients were divided according to the number of RBC, with greater than 10,000/mm³ being described as hemorrhagic ascites, and less than 10,000/mm³ described as the normal or control group. Patient data included: number of accepted intensive unit service stays, acute kidney injury (AKI), hepatic encephalopathy (HES), model for end-liver disease (MELD) score, Child Pugh score (CPS), degree of esophageal varices, spleen size and mortality rates. RESULTS: Patients were defined as having hemorrhagic ascites with a RBC count greater than 10,000/mm³ in 118 (35.9%) patients and as a non-hemorrhagic ascites group with less than 10,000/mm³ in 211 (64.1%) patients. The hemorrhagic ascites group had advanced liver disease symptoms compared to the control group. Meld score in the hemorrhagic group was statistically higher than in the control group (21.5±8.3 vs. 17.3±6.6; p value: 0.001). The median value of bilirubin was 5.9 (0.45-33) in the hemorrhagic ascites group and 4.01 (0.39-33) in the non-hemorrhagic group (p value: 0.001). Using multivariate logistic regression analysis, hemorrhagic ascites was also an independent predictor of mortality (HR 2.7 1.4-6.3), with other mortality indicators being HCC (HR 3.1 1.5-6.4) and HRS (HR 2.6 1.2-5.5). CONCLUSION: Patients with hemorrhagic ascites had higher HRS, SBP and admissions to the intensive care unit. We believe that the presence of hemorrhagic ascites can be used as a marker for advanced liver disease and for predicting mortality.

The Prevalence of Barrett Esophagus Diagnosed in the Second Endoscopy: A Retrospective, Observational Study at a Tertiary Center.

At present, we do not know the exact prevalence of Barrett esophagus (BE) developing later in patients without BE in their first endoscopic screening. The purpose of this study was to determine the prevalence of BE on the second endoscopic examination of patients who had no BE in their first endoscopic examination.The data of the patients older than 18 years who had undergone upper gastrointestinal system endoscopy more than once at the endoscopy unit of our clinic during the last 6 years were retrospectively analyzed.During the last 6 years, 44,936 patients had undergone at least one endoscopic examination. Among these patients, 2701 patients who had more than one endoscopic screening were included in the study. Of the patients, 1276 (47.3%) were females and 1425 (52.7%) were males, with an average age of 54.9 (18-94) years. BE was diagnosed in 18 (0.66%) of the patients who had no BE in the initial endoscopic examination. The patients with BE had reflux symptoms in their medical history and in both endoscopies, they revealed a higher prevalence of lower esophageal sphincter laxity, hiatal hernia, and reflux esophagitis when compared to patients without BE (P < 0.001).Our study showed that in patients receiving no diagnosis of BE on their first endoscopic examination performed for any reason, the prevalence of BE on their second endoscopy within 6 years was very low (0.66%).

Is there a safer electrosurgical current for endoscopic sphincterotomy in patients with liver cirrhosis?

BACKGROUND: Endoscopic sphincterotomy has a higher risk of bleeding in patients with cirrhosis. Advanced Child stage and coagulopathy are well-known risk factors. We aimed to determine the role of electrosurgical currents in the development of endoscopic sphincterotomy bleeding in cirrhotic patients. METHODS: The study was a retrospective observational study and included 19,642 patients who underwent endoscopic retrograde cholangiopancreatography between 2004 and 2013. The incidence of endoscopic sphincterotomy bleeding in cirrhotic patients who underwent sphincterotomy after 2009 with an electrosurgical generator applying alternating current in the pulse cut mode (Group 2) was compared with a historical control group who underwent endoscopic sphincterotomy between 2004 and 2009 via blended current (Group 1). RESULTS: Group 1 included 15 patients (six women, nine men, mean age: 62.2 ± 12.9 years). Group 2 included 14 patients (six women, eight men, mean age: 63.6 ± 16.9 years). There was no statistically significant difference between the demographic and clinical characteristics of the two groups. Endoscopic sphincterotomy bleeding was observed in three patients in Group 1 (two endoscopic bleeding and one clinically significant bleeding) and none of the patients in Group 2 (p = 0.77). There were no cases of perforation or pancreatitis in both groups. One patient in Group 2 developed cholangitis. CONCLUSIONS: Endoscopic sphincterotomy bleeding is less frequently observed in patients with cirrhosis who underwent sphincterotomy with alternating mixed current in the pulse cut mode compared with those with blended current.