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Video 1EUS-directed transgastric ERCP in twice-surgically-altered anatomy: Roux-en-Y gastric bypass conversion of a sleeve gastrectomy.
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The present study investigates the ecotoxicity of 7 biofertilizers, including biowaste-derived organic matrices. Real-field tests were conducted to assess the impacts of soil fertilization with sewage sludge digestate from high-solid thermophilic anaerobic digestion (HSTAD) compared to those obtained on non-amended and urea-fertilized soils. The physical-chemical and ecotoxic impact of HSTAD digestate on soil was monitored for 12 months, at 5 time points and 2 soil depths, on a maize field divided in 3 portions (non-treated, fertilized with urea, amended with digestate). The chemical and physical characteristics of the soil were previously analyzed for 3 years to provide a long-term outlook of the impacts of biofertilizer application. Seven bioindicators were utilized for direct (on whole soil) and indirect (on soil elutriates) ecotoxicological tests on fertilizers and amended soils, including plant seeds (Lepidium sativum, Sorghum saccharatum, and Sinapsis alba), the aquatic organism Daphnia magna, the alga Raphidocelis subcapitata, the luminescent bacterium Aliivibrio fischeri, and the Nematode Caenorhabditis elegans. No serious negative effects on soil fertilized with HSTAD digestate were evidenced. Conversely, bioassays rather showed positive effects, encouraging the utilization of HSTAD digestate in agriculture, considering the proper concentrations of use. The obtained data were interpolated and a test battery integrated index was generated, confirming the absence of ecotoxicological risk for the soils amended with the applied fertilizers. The long-term evolution of the physical-chemical soil characteristics (including the concentrations of potential contaminants) was similar for both HSTAD digestate and urea application as well as for non-fertilized soil, indicating no negative effects due to digestate application on land. On the contrary, digestate application improved the content of stabilized organic matter and nutrients in soil. This study proposes a more correct approach to ecotoxicity assessment of fertilized soils for biofertilizer evaluation and demonstrates the long-term safe application of HSTAD digestate on agricultural soil.
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Fertilizantes , Solo , Solo/química , Fertilizantes/análise , Agricultura , Esgotos/química , Fertilização , UreiaRESUMO
This study investigated the optimum pH, temperature, and food-to-microorganisms (F/M) ratio for regulating the formation of electron acceptors and donors during acidogenic fermentation to facilitate medium-chain carboxylic acids (MCCAs) production from food waste. Mesophilic fermentation at pH 6 was optimal for producing mixed volatile fatty acids (719 ± 94 mg COD/g VS) as electron acceptors. Under mesophilic conditions, the F/M ratio (g VS/g VS) could be increased to 6 to generate 22 ± 2 g COD/L of electron acceptors alongside 2 ± 0 g COD/L of caproic acid. Thermophilic fermentation at pH 6 was the best condition for producing lactic acid as an electron donor. However, operating at F/M ratios above 3 g VS/g VS under thermophilic settings significantly reduced lactic acid yield. A preliminary techno-economic evaluation revealed that converting lactic acid and butyric acid generated during acidogenic fermentation to caproic acid was the most profitable food waste valorization scenario and could generate 442-468 /t VS/y. The results presented in this study provide insights into how to tailor acidogenic fermentation reactions to desired intermediates and will help maximize MCCAs synthesis.
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Caproatos , Eliminação de Resíduos , Fermentação , Alimentos , Ácidos Carboxílicos , Elétrons , Ácidos , Ácido LácticoRESUMO
A lab-scale integrated fixed-film activated sludge (IFAS) reactor was mplemented with the oxic-settling anaerobic (OSA) cycle for reducing sewage sludge production through the addition of an anoxic/anaerobic sludge holding tank (SHT) along the sludge recycle line. The IFAS-OSA system was operated under the different hydraulic retention time (HRT) in the SHT (HRTSHT) of 12 h and 6 h, at an oxidation-reduction potential (ORP) < -91 mV and solid retention time (SRT) between 39 and 126 d. Furthermore, the effect of temperature increase in the SHT (TSHT) from ambient (19.8-25.6 °C) to mesophilic (35 °C) conditions was investigated. The system performances were monitored in terms of sludge minimization and dewaterability efficiencies as well as carbon and nutrients reduction. The observed sludge yield (Yobs) for the IFAS system was 0.37(±0.06) mg VSS/mg COD. After OSA implementation Yobs decreased by 32% and 46-65% at HRTSHT of 12 h and 6 h, respectively, indicating that prolonged exposure to anoxic/anaerobic conditions was not beneficial for sludge reduction. The lowest Yobs of 0.09(±0.05) mg VSS/mg COD (76% lower than that in the IFAS system) was obtained at an HRTSHT of 6 h and when TSHT was set at 35 °C. OSA implementation did not affect COD and NH4+ oxidation of the IFAS system (90-96% and 99%, respectively) and improved total nitrogen (TN) reduction (31-53%) due to improved denitrification in the SHT. On the contrary, sludge dewaterability worsened following OSA implementation, which was linked to the increased levels of exopolymeric substances in the suspended biomass.
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Esgotos , Eliminação de Resíduos Líquidos , Anaerobiose , Reatores Biológicos , NitrogênioRESUMO
Anaerobic digestion (AD) is a sustainable and well-established option to handle sewage sludge (SS), as it generates a methane-rich biogas and a digestate with potential fertilizing properties. In the past, different strategies have been proposed to enhance the valorization of SS. Among these, the application of a static magnetic field (SMF) has been poorly evaluated. This study aims to determine the effects of a high-intensity SMF (1.5 and 2 T) on the chemical composition of SS anaerobic digestate. Several strategies (i.e., number of magnetization cycles, addition of different sources and quantities of magnesium, and digestate aeration) have been applied to evaluate the possible formation of compounds with valuable fertilizing properties in the digestate. Experimental results showed that by combining different strategies promoting digestate exposure to the magnetic field it is possible to favour the reduction in the liquid phase of NH4+, NO3-, PO43-, SO42- and Mg2+ concentrations up to 28%, 38%, 34%, 39% and 31%, respectively. The XRD analyses conducted on the solid phase of the same magnetized digestate samples showed an increase in crystalline and amorphous phases of nitrogen and phosphorus compounds with fertilizing value, such as struvite. These results highlight that SMF application can increase the fertilizing potential of sewage sludge digestate and promote its valorization in a sustainable and circular perspective.
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The photosensitivity, responsivity, and signal-to-noise ratio of organic phototransistors depend on the timing characteristics of light pulses. However, in the literature, such figures of merit (FoM) are typically extracted in stationary conditions, very often from IV curves taken under constant light exposure. In this work, we studied the most relevant FoM of a DNTT-based organic phototransistor as a function of the timing parameters of light pulses, to assess the device suitability for real-time applications. The dynamic response to light pulse bursts at ~470 nm (close to the DNTT absorption peak) was characterized at different irradiances under various working conditions, such as pulse width and duty cycle. Several bias voltages were explored to allow for a trade-off to be made between operating points. Amplitude distortion in response to light pulse bursts was also addressed.
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INTRODUCTION: Laparoscopic sleeve gastrectomy (SG) has rapidly become one of the most commonly performed procedures in bariatric surgery. Weight regain and insufficient weight loss are the most common causes for surgical failure. Re-sleeve gastrectomy (ReSG) can represent an option when there is evidence of a dilated gastric tube. OBJECTIVES: The aim of the study is to evaluate safety, efficacy and rate of gastro-esophageal reflux disease (GERD) after ReSG in one of the largest series present in literature with long-term follow up. METHODS AND STUDY DESIGN: Retrospective study design. From February 2010 to August 2018, 102 patients underwent ReSG at our Centre. We divided patients into two groups, according to the main reason for surgical failure: insufficient weight loss or progressive weight regain. RESULTS: One hundred-two patients (78 women, 24 men) with BMI 38 ± 6 kg/m2 underwent ReSG (mean age 44 years). Rate of postoperative complications was 3.9% (4/102). After a mean follow-up of 55 months, mean BMI decreased to 30,4 kg/m2 and the mean percentage of excess weight loss (%EWL) was 51 ± 38.6. Symptoms of GERD were present in 35/102 patients (34.3%) and the need for a new operation occurred in six patients. Forty-five patients were submitted to ReSG for progressive weight regain (group A) and 57 for insufficient weight loss (group B). No differences were found in terms of postoperative BMI and %EWL. CONCLUSION: ReSG is a feasible procedure after primary SG failure in selected patients, but its efficacy in reducing the BMI under 30 kg/m2 is still unclear. In addition, over 30% of patients suffer from long-term gastro-esophageal reflux.
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Refluxo Gastroesofágico , Laparoscopia , Obesidade Mórbida , Masculino , Humanos , Feminino , Adulto , Seguimentos , Estudos Retrospectivos , Reoperação/efeitos adversos , Laparoscopia/métodos , Refluxo Gastroesofágico/epidemiologia , Refluxo Gastroesofágico/cirurgia , Refluxo Gastroesofágico/etiologia , Gastrectomia/métodos , Redução de Peso , Aumento de Peso , Obesidade Mórbida/cirurgia , Obesidade Mórbida/complicações , Resultado do TratamentoRESUMO
PURPOSE: Sleeve gastrectomy, the most commonly performed bariatric surgery procedure, carries limitations both short term including postoperative complications such as hemorrhage and gastric fistula and long term such as weight regain and gastroesophageal reflux. A new procedure has been proposed to overcome many of these limitations: laparoscopic vertical clip gastroplasty (LVCG) with BariClip. MATERIALS AND METHODS: Fifty patients were offered LVCG and enrolled for a feasibility study in two referral bariatric centers. Indication was given as for sleeve gastrectomy, after a multidisciplinary path evaluating age, gender, BMI, comorbidities, eating behaviors, and gastroesophageal reflux. The primary outcome was major postoperative complications. Secondary outcomes included weight loss, incidence of de-novo GERD, and comorbidity resolution. RESULTS: Patients had a mean age of 44 years and mean BMI of 37 kg/m2 ± 6.2. All procedures were performed successfully in laparoscopy, with no conversion or intraoperative adverse events. The overall major postoperative complication rate was 6%. Re-operation was required in three patients for slippage. No mortality occurred. Excess weight loss, excess BMI loss, and total weight loss at 6 months were 36%, 57%, and 22%, respectively. There was no instance of de-novo GERD. Resolution of hypertension occurred in 50% of cases, OSAS in 65% of cases, and DMII in 80% of cases. CONCLUSION: The safety of LVCG procedure has been reproduced in a multicentric, multi-surgeon study. Weight loss outcomes appear promising. A randomized trial is needed to fully assess the benefits of LVCG.
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Refluxo Gastroesofágico , Gastroplastia , Laparoscopia , Obesidade Mórbida , Humanos , Adulto , Gastroplastia/efeitos adversos , Gastroplastia/métodos , Obesidade Mórbida/cirurgia , Gastrectomia/métodos , Refluxo Gastroesofágico/etiologia , Laparoscopia/efeitos adversos , Laparoscopia/métodos , Redução de Peso , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/cirurgia , Complicações Pós-Operatórias/etiologia , Instrumentos Cirúrgicos/efeitos adversos , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Phosphorus (P) is an essential element to produce feed and fertilizers but also a nonrenewable resource. Both the predicted exhaustion of phosphatic rocks and the risk of eutrophication lead to an increasing necessity for P recovery methodologies to be applied in municipal wastewater treatment plants (WWTPs). One of the most promising solutions involves the precipitation of P-based minerals reusable as slow-release fertilizers. In this study, P recovery as struvite and hydroxyapatite from a municipal WWTP digestate liquid fraction (centrate) was investigated at varying pH (8-10), reagent typologies (MgCl2 , NaOH, Ca(OH)2 , and CaCl2 ), and concentrations under limiting magnesium doses through liquid- and solid-phase analyses and thermodynamical modeling. A maximum P recovery of 87.3% was achieved at pH 9 by adding NaOH and MgCl2 at a dose of 656 mg/L (the higher tested). According to these data, it was estimated that 92.0 tons/year of struvite and 33.2 tons/year of hydroxyapatite could be recovered from the WWTP centrate with a cost for reagent consumption being almost 50% of the mean P market value. An increase in P precipitation was observed while comparing experiments with the same pH values but with a higher Mg2+ dose. Ca2+ addition led to extensive P precipitation but mainly as amorphous phases that interfere with struvite formation.
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Fósforo , Esgotos , Estruvita , Magnésio , Compostos de Magnésio , Durapatita , Fertilizantes , Hidróxido de Sódio , FosfatosRESUMO
Background: Laparoscopic sleeve gastrectomy (LSG) is associated with the long-term development of gastroesophageal reflux disease (GERD). Recent studies on LSG with fundoplication showed a lower rate of postoperative GERD than LSG alone; however, there is a lack of objective instrumental data in the literature. This study aimed to evaluate whether and how fundoplication associated with Sleeve Gastrectomy affects the esophagogastric physiology. Materials and Methods: This prospective observational study included 20 patients with morbid obesity, GERD, and lower esophageal sphincter (LES) hypotonia. All the patients underwent LSG with Rossetti fundoplication. High-resolution manometry was performed pre- and postoperatively. All the patients completed the 6 months follow-up. Results: The fundoplication increased LES tone in all patients. The increase in the LES tone was statistically significant (330% increase). The integrated relaxation pressure and the distal contractile integral both increased accordingly, indicating an increased esophageal effort to pass through the modified esophagogastric junction. Conclusion: Rossetti fundoplication associated with LSG increased LES tone and decreased the chance of developing long-term GERD after LSG.
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Refluxo Gastroesofágico , Laparoscopia , Obesidade Mórbida , Humanos , Esfíncter Esofágico Inferior/cirurgia , Fundoplicatura , Refluxo Gastroesofágico/cirurgia , Gastrectomia , Manometria , Obesidade Mórbida/cirurgia , Resultado do TratamentoRESUMO
Water resource recovery facilities are faced with stringent effluent phosphorus limits to reduce nutrient pollution. Enhanced biological phosphorus removal (EBPR) is the most common biological route to remove phosphorus; however, many facilities struggle to achieve consistent performance due to limited carbon availability in the influent wastewater. A promising process to improve carbon availability is through return activated sludge (RAS) fermentation via sidestream EBPR (S2EBPR). In this study, a full-scale S2EBPR pilot was operated with a sidestream plus carbon configuration (SSRC) at a carbon-limited facility. A model based on the pilot test was developed and calibrated in the SUMO platform and used to explore routes for improving orthophosphate (OP) effluent compliance. Modeling results showed that RAS diversion by itself was not sufficient to drive OP removal to permit limits of 1 mg L-1, therefore, other strategies were evaluated. Supplemental carbon addition of MicroC® at 1.90 L min-1 and controlling the phosphorus concentration below 3.5 mgP L-1 in the primary effluent (PE) proved to be valid supplemental strategies to achieve OP removal below 1 mg L-1 most of the time. In particular, the proposed supplemental carbon flow rate would result in an improvement of the rbCOD:P ratio from 17:1 to 26:1. The synergistic approach of RAS diversion and supplemental carbon addition increased the polyphosphate accumulating organisms (PAO) population while minimizing the supplemental carbon needed to achieve consistent phosphorus removal. Overall, this pilot and modeling study shows that joint strategies, including RAS diversion, carbon addition and PE control, can be effective to achieve optimal control of OP effluent.
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Fósforo , Águas Residuárias , Carbono , Reatores Biológicos , EsgotosRESUMO
Lignocellulosic materials (LCM) have garnered attention as feedstocks for second-generation biofuels and platform chemicals. With an estimated annual production of nearly 200 billion tons, LCM represent an abundant source of clean, renewable, and sustainable carbon that can be funneled to numerous biofuels and platform chemicals by sustainable microbial bioprocessing. However, the low bioavailability of LCM due to the recalcitrant nature of plant cell components, the complexity and compositional heterogeneity of LCM monomers, and the limited metabolic flexibility of wild-type product-forming microorganisms to simultaneously utilize various LCM monomers are major roadblocks. Several innovative strategies have been proposed recently to counter these issues and expedite the widespread commercialization of biorefineries using LCM as feedstocks. Herein, we critically summarize the recent advances in the biological valorization of LCM to value-added products. The review focuses on the progress achieved in the development of strategies that boost efficiency indicators such as yield and selectivity, minimize carbon losses via integrated biorefinery concepts, facilitate carbon co-metabolism and carbon-flux redirection towards targeted products using recently engineered microorganisms, and address specific product-related challenges, to provide perspectives on future research needs and developments. The strategies and views presented here could guide future studies in developing feasible and economically sustainable LCM-based biorefineries as a crucial node in achieving carbon neutrality.
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Biocombustíveis , Lignina , Biomassa , Lignina/metabolismo , CarbonoRESUMO
This paper describes the scintillation features and the radiation damage in polyethylene naphthalate 100 µm-thick scintillators irradiated with an 11 MeV proton beam and with a 1 MeV electron beam at doses up to 15 and 85 Mrad, respectively. The scintillator emission spectrum, optical transmission, light yield loss, and scintillation pulse decay times were investigated before and after the irradiation. A deep blue emission spectrum peaked at 422 nm, and fast and slow scintillation decay time constants of the order of 1-2 ns and 25-30 nm, respectively, were measured. After irradiation, transmittance showed a loss of transparency for wavelengths between 380 and 420 nm, and a light yield reduction of ~40% was measured at the maximum dose of 85 Mrad.
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Nitrate (NO3-) contamination of groundwater is a major health concern worldwide as it can lead to serious illnesses such as methemoglobinemia and cancer. Autotrophic denitrification is a smart approach for treating groundwater, being typically organic-deficient. Lately, biogenic sulfur (S0bio) has emerged as a sustainable, free, and high-efficiency substrate to fuel membrane bioreactors (MBRs) treating contaminated groundwater. However, the effects of moderate temperature and biomass concentration on the performance and fouling of the S0bio-fed MBR were not investigated previously. This study shows that biomass levels of ~1 g MLVSS/L limit membrane fouling but also denitrification efficiency. Biomass augmentation up to 3 g MLVSS/L enhanced denitrification but worsened fouling due to increase of extracellular polymeric substance (EPS) levels in the bulk liquid. Temperature decrease from 30 °C to 20 °C halved denitrification efficiency, which could be partially recovered through bioaugmentation. The mechanisms affected by temperature decrease, practical applications, and future research needs were discussed.
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Água Subterrânea , Nitratos , Nitratos/química , Desnitrificação , Biomassa , Temperatura , Matriz Extracelular de Substâncias Poliméricas , Reatores Biológicos , Água Subterrânea/química , Enxofre/química , Óxidos de Nitrogênio , NitrogênioRESUMO
Pyrite-driven autotrophic denitrification (PAD) represents a cheap and promising way for nitrogen removal from organic-limited wastewater, which has obtained increasing attention in recent years. However, the limited denitrification rate and unclear mechanism underlying the process have hindered the engineered application of PAD. This study aims to shed light on the impacts of different pretreatments (i.e., ultrasonication, acid-washing and calcination) on micron-pyrite surface characteristics, denitrification performance and biofilm formation during PAD in batch reactors. A series of solid-phase analyses revealed that all pretreatments could significantly promote biofilm attachment on pyrite granules, but impacted the proportion, distribution and chemical oxidation state of sulfur (S) and iron (Fe) at varying degrees. Batch tests showed that ultrasonication and acid-washing could enhance the total nitrogen reduction rate by 14% and 99%, and decrease the sulfate production rate by 51% and 42%, respectively, when compared with untreated pyrite. Microbial community analysis indicated that Thiobacillus and Rhodanobacter dominated in PAD systems. Two types of indirect mechanisms (i.e., contact and non-contact) for pyrite leaching may co-occur in PAD system, resulting in ferrous iron (Fe2+), thiosulfate (S2O32-) and sulfide (S2-) as the main electron donors for denitrification. A PAD mechanism model was proposed to describe the PAD electron transfer pathway with the aim to optimize the engineered application of PAD for nitrogen removal.
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Desnitrificação , Águas Residuárias , Processos Autotróficos , Reatores Biológicos , Ferro , Nitratos , Nitrogênio , Sulfatos , Sulfetos , Enxofre , TiossulfatosRESUMO
Excess sludge production in wastewater treatment plants has become an enormous environmental issue worldwide mainly due to the increased efforts towards wastewater purification. Researchers and plant operators are looking for technological solutions to reduce sludge production through the upgrading of existing technologies and configurations or by substituting them with alternative solutions. Several strategies have been identified to reduce sludge production, including the use of biological and physical-chemical methods (or a combination of them) and novel technologies, although many have not been sufficiently tested at full-scale. To select the most suitable system for sludge reduction, understanding the reduction mechanisms, advantages, disadvantages, and the economic and environmental impact of each technology is essential. This work offers a comprehensive and critical overview of mainstream sludge reduction technologies and underlying mechanisms from laboratory to full scale, and describes potential application, configuration, and integration with conventional systems. Research needs are highlighted, and a techno-economic-environmental comparison of the existing technologies is also proposed.
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Esgotos , Purificação da Água , Reatores Biológicos , Eliminação de Resíduos Líquidos/métodos , Águas ResiduáriasRESUMO
Simultaneous nitrification-denitrification (SND) is an advantageous bioprocess that allows the complete removal of ammonia nitrogen through sequential redox reactions leading to nitrogen gas production. SND can govern nitrogen removal in single-stage biofilm systems, such as the moving bed biofilm reactor and aerobic granular sludge system, as oxygen gradients allow the development of multilayered biofilms including nitrifying and denitrifying bacteria. Environmental and operational conditions can strongly influence SND performance, biofilm development and biochemical pathways. Recent advances have outlined the possibility to reduce the carbon and energy consumption of the process via the "shortcut pathway", and simultaneously remove both N and phosphorus under specific operational conditions, opening new possibilities for wastewater treatment. This work critically reviews the factors influencing SND and its application in biofilm systems from laboratory to full scale. Operational strategies to enhance SND efficiency and hints to reduce nitrous oxide emission and operational costs are provided.
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Nitrificação , Águas Residuárias , Biofilmes , Reatores Biológicos/microbiologia , Desnitrificação , Nitrogênio/metabolismo , Esgotos , Eliminação de Resíduos LíquidosRESUMO
BACKGROUND: Gastroesophageal reflux disease (GERD), including erosive esophagitis, is highly prevalent in the obese population. Barrett's esophagus is the consequence of untreated GERD. Laparoscopic sleeve gastrectomy is one of the most frequently performed bariatric procedures. This study presents results after 5 years of follow-up of combined LSG and Rossetti fundoplication for the treatment of GERD, esophagitis, and Barrett's esophagus in patients with morbid obesity. OBJECTIVE: To evaluate long-term results after sleeve gastrectomy with Rossetti fundoplication. SETTING: Public university hospital in Italy. METHODS: Since January 2015, more than 450 patients with obesity underwent sleeve gastrectomy with a Rossetti fundoplication procedure as part of prospective studies underway at our center performed by 4 different expert bariatric surgeons. Currently, 127 patients have a follow-up of 5 years or more. RESULTS: Mean patient age was 42.9 ± 10.3 years, and mean body mass index was 42.4 ± 6.1 kg/m2. In total, 74.8% of patients were experiencing GERD before surgery. In 29 of 127 patients (22.8%), preoperative gastroscopy showed signs of esophagitis and/or Barrett's esophagus. In particular, 23 of 127 patients (18.1%) had grade A esophagitis, 2 of 127 (1.6%) had grade B, 2 of 127 (1.6%) had grade C, and 2 of 127 (1.6%) had Barrett's esophagus. Mean operative time was 51 ± 21 minutes. No intraoperative complications or conversions were reported. A regular postoperative course was seen in 91.3% of patients. Sixty months after surgery, more than 95% of patients did not experience any reflux symptoms. Percent total weight loss at follow-up was comparable with that with sleeve gastrectomy. Endoscopic follow-up demonstrated improvement of esophagitis lesions (including Barrett's esophagus) present in the preoperative setting. CONCLUSION: Laparoscopic sleeve gastrectomy with Rossetti fundoplication is well tolerated, feasible, and safe in patients with obesity, providing adequate weight loss results and complete resolution of clinical signs of GERD. We have recorded an improvement in esophagitis lesions present at preoperative gastroscopy and complete resolution of Barrett's esophagus within 5 years of follow-up.
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Esôfago de Barrett , Esofagite , Refluxo Gastroesofágico , Laparoscopia , Obesidade Mórbida , Adulto , Esôfago de Barrett/diagnóstico , Esôfago de Barrett/cirurgia , Esofagite/etiologia , Esofagite/cirurgia , Seguimentos , Fundoplicatura/métodos , Gastrectomia/métodos , Refluxo Gastroesofágico/complicações , Refluxo Gastroesofágico/cirurgia , Humanos , Laparoscopia/métodos , Pessoa de Meia-Idade , Obesidade Mórbida/complicações , Estudos Prospectivos , Redução de PesoRESUMO
This study demonstrates the feasibility of pyrite-assisted denitrification to treat mildly acidic wastewaters and proposes a convenient solution for nitrogen removal from acidic mining waters. Pyrite is a highly available and low-cost electron donor for autotrophic denitrification, whereas mining waters represent a source of nitrogen (N) contamination due to the use of N-containing explosives during mining operations and cyanide (CN)-based compounds for ore processing. In this study, the denitrification performance of a recirculated pyrite-packed biofilter (RPPB) treating simulated N-contaminated acidic mining waters is evaluated under decreasing pH conditions. The effect of feed organic carbon on the autotrophic process has been also investigated. N removal efficiencies (NRE) > 60% could be achieved at feed pH ≥ 4.5 and HRT ≥ 5 h. Decrease of influent pH to 3.0 reduced the NRE to 20%. The addition of 10 and 20 mg/L of ethanol to the influent did not significantly impact NRE of the RPPB. PRACTITIONER POINTS: Pyrite-assisted denitrification is proposed for treating acidic wastewaters. Nitrogen removal >60% was maintained at feed pH as low as 4.7. Decrease of feed pH to 3 strongly inhibited denitrification. The presence of organic carbon in the feed did not affect the autotrophic process.
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Introduction: Staple-line bleeding and gastric leakage are the most serious complications of laparoscopic sleeve gastrectomy (LSG). Reinforcement of the staple line is reported to be a method to reduce these complications rates, but the question of which method is preferable is a matter of controversy in the literature. In this study, we compared different staple-line reinforcement methods to assess their efficiency in preventing staple-line bleeding and leakage. Materials and Methods: Two hundred patients eligible for LSG were enrolled in the study and randomized into five groups based on the reinforcement method used during surgery: no reinforcement, oversewing using 3-0 polydioxanone (PDS) suture, oversewing using 4-0 barbed absorbable closure device (V-Lock), fibrin sealant glue, and buttress material. Intraoperative and postoperative complications were recorded and analyzed. Differences were considered statistically significant for P < .05. Results: The no-reinforcement group showed higher bleeding rates (20%), although only 2.5% of the patients required reintervention. All groups using staple-line reinforcement showed better outcomes in bleeding rates (P < .05). No statistically significant differences were observed among the groups in terms of the leakage rate, reintervention rate, intraoperative complications, and operative times. Conclusion: The reinforcement of the staple line decreased the bleeding rate in sleeve gastrectomy but did not affect the gastric leakage rate.