Digestion Treatment Research Articles

Suspected cerebrovascular air embolism during endoscopic esophageal varices ligation under sedation with fatal outcome: A case report

BACKGROUNDAir embolism is a very rare, yet serious and potentially fatal complication of digestive endoscopic treatment. Air embolism is the result of air directly entering the arteries or veins. However, to recognize neurological dysfunction under sedation can be difficult. Therefore, it is extremely important to identify high-risk groups and take preventive measures.CASE SUMMARYHerein, we report a 74-year-old female patient with esophageal varices who suffered from consciousness disturbance after the third endoscopic ligation of esophageal varices under sedation. Combined with the patient’s imaging examination results and medical history, we highly suspected that the patient had developed paradoxical cerebral air embolism during endoscopic ligation. We learned that the patient died at a later follow-up. In order to be able to identify and prevent the occurrence of air embolism early, we summarize and analyze the risk factors, pathogenesis, clinical manifestations, prevention and treatment options of gastrointestinal endoscopy complicated by cerebral air embolism.CONCLUSIONElectroencephalographic monitoring helps to recognize the occurrence of air embolism in time and increase the patient's chance of survival.

Digestate Potential to Substitute Mineral Fertilizers: Engineering Approaches

The study aims to define the potential and technological aspects of the digestate treatment for its application as a biofertilizer. Life cycle assessment methodology was used in terms of digestate quality management. The potential of nutrients, organic carbon, and useful microelements in the digestate allows for its consideration as a mineral fertilizer substitute and soil improver. The valorization of digestate as fertilizer requires quality management and quality control. Based on the research focus, the successful soil application of digestate post-treatment technologies was analyzed. Among the different commercial options for digestate treatment and nutrient recovery, the most relevant are drying, struvite precipitation, stripping, evaporation, and membranes technology. Comparing the physical and chemical properties of the whole digestate, separated liquid, and solid liquor fractions showed that in the case of soil application of granular fertilizer, nutrients from the digestate are released more slowly than digestate application without granulation. However, realizing this potential in an economically feasible way requires improving the quality of digestate products through appropriate technologies and quality control of digestate products. To support the manufacture of quality digestate across Europe, the European Compost Network developed a concept for a pan-European quality assurance scheme.

Insight into the Effects of Hydroxylamine in a Pn-Anammox System During the Treatment of Anaerobic Digestate of Pig Manure (Adpm)

Insight into the Effects of Hydroxylamine in a Pn-Anammox System During the Treatment of Anaerobic Digestate of Pig Manure (Adpm)

Hygienic assessment of digestate from a high solids anaerobic co-digestion of sewage sludge with biowaste by testing Salmonella Typhimurium, Escherichia coli and SARS-CoV-2

Anaerobic digestion is a consolidated technology to convert sewage sludge and other organic wastes into biogas and a nutrient-rich fertilizer (i.e. digestate). The origin of sewage sludge does not exclude the potential presence of pathogens (e.g. Salmonella spp. and SARS-CoV-2) in mature digestate that hence could represent a source of sanitary concerns when it is spread on soil for agriculture purpose. Therefore, an experimental study aimed at proving the sanitizing effect of a full scale thermophilic high solids anaerobic digestion process was conducted by monitoring the hygienic characteristics of mature digestate. Although Salmonella spp. was detected in the sewage sludge fed to the full scale plant, the anaerobic digestion treatment demonstrated sanitization capacity since the monitored pathogens were never found in the mature digestate over the entire duration of the monitoring survey. Furthermore, tests on the regrowth of Salmonella Typhimurium and Escherichia coli, artificially inoculated on mature digestate, were also conducted under both anaerobic and aerobic conditions with the aim to assess the effectiveness of mature digestate as microbial growth medium. Concentrations of Salmonella Typhimurium and Escherichia coli were drastically reduced after a short time of incubation under anaerobic process and the two microorganisms already resulted undetectable after 24–48 h, whereas, under aerobic conditions, two microorganisms’ concentrations were stably high for longer than 10 days. The combination of no free oxygen, high temperature, anaerobic metabolites (e.g. total ammonium nitrogen, and volatile fatty acids) production, bacteria competition and lack of nutritional elements in mature digestate considerably reduced in 24–48 h the sanitary risks associated to accidently contaminated digestate. Furthermore, a SARS-CoV-2 monitoring survey on mature digestate during 13 months, resulted in the absence of the virus RNA in the analyzed digestate.

Microalgal fuels: Promising energy reserves for the future

Traditional methods of fuel production and consumption result in the emission of huge quantities of CO2, leading to a rise in the Earth’s surface temperature. This has driven the scientific community to look for alternate sources of fuels that could fulfil the current energy demands, while reducing CO2 emissions. Microalgae have garnered substantial interest as an excellent biological resource for biorefineries, given their abilities to accumulate diverse CO2-derived bioproducts, such as various forms of fuels, chemical building blocks, and pharmaceuticals; this could be interpreted as an efficient method for storing solar energy by biological means. Microalgal biomass is free from ethical debates because it does not compete with food production for fertile arable lands and clean water for their cultivation, which makes the entire process highly sustainable. Microalgal biomass-derived fuels for each end-use can be obtained via several processes, including drying, chemical, and physical lipid-extraction methods, anaerobic digestion, and thermochemical treatments (e.g., pyrolysis, torrefaction, hydrothermal carbonization, liquefaction, and gasification). This review aims to critically explore the process layouts, their operation conditions (including catalysts), and expected outputs related to fuel production. It also provides a comprehensive overview of the most notable and promising strategies for the producing energy resources from various species of microalgae. Pretreatment of microalgal biomass, followed by bioconversion strategies, such as hydrothermal carbonization and photo-fermentation, along with genomics-based approaches, can lead to higher yields of microalga-derived solid, liquid, and gaseous fuels.

Feasibility of Coupling Anaerobic Digestion and Hydrothermal Carbonization: Analyzing Thermal Demand

Anaerobic digestion is a biological process with wide application for the treatment of high organic-containing streams. The production of biogas and the lack of oxygen requirements are the main energetic advantages of this process. However, the digested stream may not readily find a final disposal outlet under certain circumstances. The present manuscript analyzed the feasibility of valorizing digestate by the hydrothermal carbonization (HTC) process. A hypothetical plant treating cattle manure and cheese whey as co-substrate (25% v/w, wet weight) was studied. The global performance was evaluated using available data reported in the literature. The best configuration was digestion as a first stage with the subsequent treatment of digestate in an HTC unit. The treatment of manure as sole substrate reported a value of 752 m3/d of biogas which could be increased to 1076 m3/d (43% increase) when coupling an HTC unit for digestate post-treatment and the introduction of the co-substrate. However, the high energy demand of the combined configurations indicated, as the best alternative, the valorization of just a fraction (15%) of digestate to provide the benefits of enhancing biogas production. This configuration presented a much better energy performance than the thermal hydrolysis pre-treatment of manure. The increase in biogas production does not compensate for the high energy demand of the pre-treatment unit. However, several technical factors still need further research to make this alternative a reality, as it is the handling and pumping of high solid slurries that significantly affects the energy demand of the thermal treatment units and the possible toxicity of hydrochar when used in a biological process.

Greening Ultrasound-Assisted Extraction for Sorghum Flour Multielemental Determination by Microwave-Induced Plasma Optical Emission Spectrometry.

Sorghum is the fourth most important cereal produced in Argentina and the fifth worldwide. It has good agronomic characteristics and could be developed in arid areas, allowing a wide geographic distribution. Its starch content, higher than 70%, makes it possible to obtain a good yield of flours. Nutritionally, it should be noted that the grain does not have the protein fraction called prolamins, which makes it suitable for consumption by people with celiac disease. The multielemental composition constitutes an important indicator of the nutritional profile of the grains and allows, together with other parameters, to select the most suitable varieties for human consumption. In its determination, the preanalytical stage is decisive to obtain a reliable result. Organic samples are a challenge for sample introduction systems that use plasma-based techniques. As an alternative to conventional pretreatment with a microwave-assisted digestion (MWAD), a greener, quick, and simple treatment is proposed, using ultrasound-assisted extraction (UAE) in diluted acid media. The UAE method accelerates analysis times, improves performance and productivity, and was applied to sorghum samples cultivated in the province of La Pampa (Argentina). Microwave-induced plasma optical emission spectrometry (MIP OES) was employed for the determination of Cu, K, Mg, Mn, P, and Zn. The detection limits found ranged from 0.6 (Cu) to 89 (P) mg kg−1, and the precision expressed by the relative standard deviation (RSD) was ≤7.7% (Zn). For validation, a maize reference material (NCS ZC 73010) was evaluated. The principal component analysis revealed three different groupings related to the sorghum varieties' mineral profile.

Modeling biogas production from anaerobic wastewater treatment plants using radial basis function networks and differential evolution

This study presents a new method for modeling biogas production obtained from anaerobic digestion treatment plants with increased accuracy. The method is based on artificial neural networks (ANNs) and more specifically on the efficient architecture of radial basis function (RBF) networks. A novel RBF training scheme is proposed, based on the non-symmetric fuzzy means (NSFM) algorithm, which has been shown to offer increased accuracy compared to other ANN methods, but cannot handle efficiently a large number of input variables. As this is the case in biogas production modeling, the algorithm is enhanced with an optimizer based on differential evolution (DE), which helps to properly tune the algorithm, ultimately boosting the accuracy of the produced models. The proposed approach is applied for modeling the biogas production on a real world, full-scale operational wastewater treatment plant. A comparison study shows the superiority of the proposed model, compared to different machine learning approaches.

Effect of hydrothermal carbonization pretreatment on the pyrolysis behavior of the digestate of agricultural waste: A view on kinetics and thermodynamics

Anaerobic digestion is the most promising disposal methods to treat organic waste. Also, a feasible management is necessary for the resulted digestate. Hydrothermal carbonization (HTC) combination with pyrolysis could be a proper solution to use for the treatment of digestate. In this study, the effect of an HTC on the pyrolysis of the digestate of agricultural waste (AWD) was investigated, focusing on the kinetic and thermodynamic aspects. Three model-free methods, including Friedman, KAS, and OFW methods, were used to evaluate the kinetic performance of the total and pseudo pyrolytic reactions of AWD and its hydrochar. Furthermore, kinetic predictions were made to provide more information for further studies. It was found that the HTC treatment decreased the activation energy ranges of the pyrolysis of AWD from 182.9–274.43 kJ/mol to 144.59–205.20 kJ/mol by using the Friedman method. For a more thorough understanding of the effect of HTC treatment on the pyrolysis of AWD, the pyrolysis reactions of AWD and its hydrochar were divided into two pseudoreactions using the Fraser-Suzuki deconvolution method. The mean activation energy of the deduced pseudo 2 pyrolytic reaction of hydrochar was 175.64 kJ/mol, which was 28.11 kJ/mol less than that of AWD. In addition, the ΔH‡ values of the pseudo 2 reactions of AWD and its hydrochar were 197.97 and 169.68 kJ/mol, respectively. The results of kinetic isothermal predictions suggested that the peak temperature for the further research and application of the pyrolysis of AWD and its hydrochar should not be lower than 450 °C.

Molecular diversity of liquid digestate from anaerobic digestion plants for biogenic waste

The treatment and valorization of liquid digestate (ADLD) after anaerobic digestion of biogenic waste are challenging. This study used ultra-high resolution mass spectrometry to determine the molecular characteristics of ADLD collected from different full-scale plants for food waste treatment. The results indicated that there were regular differences in the dissolved organic matter (DOM) indicators among the samples from dry and wet anaerobic processes. ADLD DOM had higher H/C and O/C, and contained more easily degradable proteins. In addition, sCOD and pH were the drivers of the molecular distribution of ADLD common compounds. The same common compounds were present in the ADLD from different anaerobic digestion plants. They had a significant correlation with physicochemical characteristics. The compounds relating to plant hormones and nutrients as well as xenobiotics were both identified, suggesting that comprehensive considerations should be taken into account for the land application of ADLD.

Optimization and system energy balance analysis of anaerobic co-digestion process of pretreated textile dyeing sludge and food waste

Anaerobic digestion treatment can transform textile dyeing sludge (TDS) to resources, but direct anaerobic digestion of TDS products only little biogas. In order to improve the effect of anaerobic digestion, pre-treatment and co-anaerobic digestion were performed in this study. Two pre-treatment methods, which are thermal pre-treatment and free nitrous acid (FNA) pre-treatment, were selected for comparison. Then, food waste (FW), as the co-digestion substance, co-digested with thermally pre-treated TDS to explored the optimized ratio of pre-treated TDS and FW. Results indicated that both the two pre-treatment methods have a certain solubilization effect on TDS, but the effect of thermal pre-treatment is better than that of FNA. The optimal mixing ratio of thermally pre-treated TD and FW is 1:1. The removal rates of soluble chemical oxygen demand and aromatic amines were the highest (75% and 64%, respectively). The cumulative methane yield reached 479.9 mL CH4/g VS, which was increased by 20–40% compared to others ratios and 66.6% to the TDS. Furthermore, system energy balance analysis was evaluated. Based on the dyeing wastewater treatment plant with a daily treatment capacity of 15000 t, electricity produced by biogas can completely satisfy the electric consumption of the wastewater treatment plant and the anaerobic co-digestion system with 57.69% and 41.78% for the respective. It was found that TDS can be reused resourcefully by the AcoD and costs can be significantly reduced.

Challenges in Treatment of Digestate Liquid Fraction from Biogas Plant. Performance of Nitrogen Removal and Microbial Activity in Activated Sludge Process

Even thoughdigestate, which is continually generated in anaerobic digestion process, can only be used as fertilizer during the growing season, digestate treatment is still a critical, environmental problem. That is why the present work aims to develop a method to manage digestate in agricultural biogas plant in periods when its use as fertilizer is not possible. A lab-scale system for the biological treatment of the digestate liquid fraction using the activated sludge method with a separate denitrification chamber was constructed and tested. The nitrogen load that was added tothe digestate liquid fraction accounted for 78.53% of the total nitrogen load fed into the reactor. External carbon sources, such as acetic acid, as well as flume water and molasses, i.e., wastewater and by-products from a sugar factory, were used to support the denitrification process. The best results were obtained using an acetic acid and COD (Chemical Oxygen Demand)/NO3–N (Nitrate Nitrogen) ratio of 7.5. The removal efficiency of TN (Total Nitrogen), NH4–N (Ammonia Nitrogen) and COD was 83.73%, 99.94%, 86.26%, respectively. It was interesting to see results obtained that were similar to those obtained when using flume water and COD/NO3–N at a ratio of 8.7. This indicates that flume water can be used as an alternative carbon source to intensify biological nitrogen removal from digestate.

Exploitation of Liquid Digestate as the Sole Nutrient Source for Floating Hydroponic Cultivation of Baby Lettuce (Lactuca sativa) in Greenhouses

Sustainable agriculture relies on replacing fossil-based mineral fertilizers, which are highly cost-energetic to produce, and demand extensive use of scarce natural resources. Today, agronomic practices within the concept of circular economy are emerging and, as such, the exploitation of digestate as a biofertilizer and soil amender is extensively investigated. This study aimed at evaluating the agronomic potential of liquid digestate as the sole nutrient source for hydroponic cultivation of baby lettuce in greenhouses. Growth rate, physiological responses, concentration of secondary metabolites, and nutrient uptake were compared between baby leaf lettuce grown in digestate in concentrations of 5, 10, and 20% diluted in water (either with or without pH adjustment) and in Hoagland solution (control). Results showed that the production yield was negatively correlated with the concentration of the added digestate. Nevertheless, the antioxidant capacity was significantly enhanced in 5 and 10% liquid digestate treatments compared to the control. Additionally, the nutrient composition in the baby leaf lettuce and the reduction in nutrient concentrations in the growth media demonstrated efficient mineral uptake by the plants. Thus, the application of liquid digestate as a fertilizer in hydroponic systems is a promising practice to recover residual resources, leading to the transition towards more sustainable greenhouse production.

Prognostic and Predictive Value of Transcription Factors Panel for Digestive System Carcinoma.

PurposeDigestive system carcinoma is one of the most devastating diseases worldwide. Lack of valid clinicopathological parameters as prognostic factors needs more accurate and effective biomarkers for high-confidence prognosis that guide decision-making for optimal treatment of digestive system carcinoma. The aim of the present study was to establish a novel model to improve prognosis prediction of digestive system carcinoma, with a particular interest in transcription factors (TFs).Materials and MethodsA TF-related prognosis model of digestive system carcinoma with data from TCGA database successively were processed by univariate and multivariate Cox regression analyses. Then, for evaluating the prognostic prediction value of the model, ROC curve and survival analysis were performed by external data from GEO database. Furthermore, we verified the expression of TFs expression by qPCR in digestive system carcinoma tissue. Finally, we constructed a TF clinical characteristics nomogram to furtherly predict digestive system carcinoma patient survival probability with TCGA database.ResultsBy Cox regression analysis, a panel of 17 TFs (NFIC, YBX2, ZBTB47, ZNF367, CREB3L3, HEYL, FOXD1, TIGD1, SNAI1, HSF4, CENPA, ETS2, FOXM1, ETV4, MYBL2, FOXQ1, ZNF589) was identified to present with powerful predictive performance for overall survival of digestive system carcinoma patients based on TCGA database. A nomogram that integrates TFs was established, allowing efficient prediction of survival probabilities and displaying higher clinical utility.ConclusionThe 17-TF panel is an independent prognostic factor for digestive system carcinoma, and 17 TFs based nomogram might provide implication an effective approach for digestive system carcinoma patient management and treatment.

Hydrothermal carbonization of garden waste by pretreatment with anaerobic digestion to improve hydrohcar performance and energy recovery

Sustainable and resourceful utilization of garden waste with high lignocellulosic content remains a huge challenge, anaerobic digestion (AD) and hydrothermal treatment provide prospective technologies with achieving environmental and economic benefits. In this study, a 7–28 d AD was provided as a biomass pretreatment means and combined with hydrothermal carbonization (HTC) to treat three typical garden wastes (leaves, branches, grass). The results showed that AD pretreatment could effectively change the surface composition and structure properties of the feedstocks and thus modulating the properties of the hydrochar downstream. Compared to the unpretreatment samples, the specific surface area (SSA), higher heating value (HHV), energy density and nutrient elements (P and K) of hydrochar obtained by AD pretreatment were significantly improved and enriched, respectively. Specifically, the highest HHV of hydrochar obtained from leaves, branches, and grass were 25.71, 25.63, and 23.81 MJ/kg, which obtained with 21, 14, and 7 d of AD pretreatment respectively. The P contents of hydrochar of leaves and grass pretreated with AD for 14 and 7 d were 205% and 15% higher than those without AD pretreatment, respectively. Additionally, in this coupled system, the biomass energy recovery of 90.2% (78.2% biochar and 12.0% CH4) was achieved on leaves pretreated with AD for 21 d. Energy recovery of 81.2% (66.8% biochar, 14.4% CH4) and 71.3% (39.7% biochar, 31.6% CH4) was obtained by 14 d of AD pretreatment on branches and grass, respectively. Thus, this study enhances energy utilization efficiency and reduces secondary waste generation, providing valuable new insights into AD coupled with HTC technology.

Nursing Value Analysis and Risk Evaluation of Acute Gastroenterology Diseases.

In the Department of Gastroenterology, poor compliance, psychological anxiety, fear, and other reasons result in a high rate of breach of appointment. The failure rate of colonoscopy was 6.68. This paper proposes mastering the psychological characteristics of patients and implement humanistic care services to alleviate patients' psychological anxiety. The study found that telephone follow-up 2 days before diagnosis and treatment can let us know whether patients can come for examination and reduce the rate of nonappointment. Second, preoperative education can significantly reduce the degree of anxiety and improve the anxiety of patients. Third, the cleanliness of intestinal preparation before colonoscopy directly affects the results of colonoscopy. The incidence of missing flat adenomas due to inadequate intestinal preparation can be as high as 27%. In this paper, 7250 patients were analyzed, of which 4% failed to complete the examination, of which 32.7% were caused by unqualified intestinal preparation. The combination of telephone and network communication should be taken before colonoscopy to give education and guidance to patients, which is expected to improve intestinal preparation. To sum up, digestive endoscopic treatment technology is widely used to guide the nursing of patients after endoscopic treatment. The three effective schemes proposed in this paper can achieve higher patient satisfaction and improve the quality of nursing at the same time.

Biowastes of slaughterhouses and wet markets: an overview of waste management for disease prevention.

Slaughterhouse and wet market wastes are pollutants that have been always neglected by society. According to the Food and Agriculture Organization of the United Nations, more than three billion and nineteen million livestock were consumed worldwide in 2018, which reflects the vast amount and the broad spectrum of the biowastes generated. Slaughterhouse biowastes are a significant volume of biohazards that poses a high risk of contamination to the environment, an outbreak of diseases, and insecure food safety. This work comprehensively reviewed existing biowaste disposal practices and revealed the limitations of technological advancements to eradicate the threat of possible harmful infectious agents from these wastes. Policies, including strict supervision and uniform minimum hygienic regulations at all raw food processing factories, should therefore be tightened to ensure the protection of the food supply. The vast quantity of biowastes also offers a zero-waste potential for a circular economy, but the incorporation of biowaste recycling, including composting, anaerobic digestion, and thermal treatment, nevertheless remains challenging.

Acclimation of an algal consortium to sequester nutrients from anaerobic digestate

The objective of this research was to investigate the growth, community composition, and digestate treatment performance of a local algae consortium that was adapted to bacteria-pretreated digestate. The approach was to subculture a local consortium on pretreated dairy manure digestate and then municipal wastewater sludge digestate, allowing the community to adapt before assessing its performance. The adapted consortium was then tested for growth and nutrient removal performance on the digestates and compared to the model organism, Chlorella sorokiniana. Dramatic restructuring of the consortium took place when subcultured on the digestates with Scenedesmaceae and Chlorellaceae almost completely replacing Euglena. The consortium was consistently less productive than C. sorokiniana (184 vs. 248 mg/L/d in dairy digestate and 32 vs. 48 mg/L/d in municipal digestate, P < 0.01). Pretreatment increased growth by 81% and 500% for C. sorokiniana and the consortium, respectively, in dairy digestate (P < 0.01), and allowed for algal growth in municipal digestate.

Microaerobic Digestion of Low-Biodegradable Sewage Sludge: Effect of Air Dosing in Batch Reactors

The adoption of prolonged solid retention times during the biological treatment of urban wastewaters is a well-known strategy to reduce sewage sludge production. However, it also results in the production of a biological sludge with low percentages of biodegradable organic matter, also characterized by high humification degrees, which may hamper the anaerobic digestion treatment aimed at sludge stabilization. To accelerate the hydrolytic stage, the application of microaerobic conditions during the anaerobic digestion of low-biodegradable sewage sludge was investigated in this study. In particular, six bio-methanation tests of a real sewage sludge were carried out, introducing air in the bioreactors with doses ranging between 0 and 16.83 L air/kg VSin d, in order to evaluate the air dosage that optimizes the biomethane production and organic matter degradation. Notably, the lower air loading rates investigated in this study, such as 0.68 and 1.37 L air/kg VSin d, led to an increase in methane production of up to 19%, due to a higher degradation of total lipids and proteins. In addition, these microaerobic conditions also resulted in a decrease in the sludge humification degree and in lower volatile fatty acid accumulation.

AN IN VITRO COMPARATIVE ANALYSIS OF PROPERTIES OF PROBIOTIC BACTERIA PRESENT IN BEVERAGES

Probiotics for human consumption including Lactobacillus sp. and Acetobacter sp. are of increasing interest due to the growing evidences of health advantages associated with them. The viability of these bacteria in food as well as during transit through the gastrointestinal tract is crucial for positive health effects. The present study comparatively analyzes the survivability and functional properties of commercial probiotic drinks in a simulated gastrointestinal environment. The sample drinks were divided into two sections viz.; Dairy and Non-dairy, both containing either Lactobacillus acidophilus or Acetobacter xylinum and estimated for properties including numbers, gram character, NaCl tolerance, bile salt resistance, optimal pH and production of organic acids. Viability and activity in the gastrointestinal environment was evaluated by subjecting the above to an in vitro digestive treatment using a combination of enzymes and digestive solutions. It was observed that amongst all the selected samples, Lactobacillus acidophilus present in the dairy beverages displayed the highest probiotic potential. These microorganisms displayed the greatest NaCl (1-9%) and bile salt tolerance (0.05- 0.4%) along with maximum organic acid production (1.81%), pH resistance (2.0-7.5) as well as overall survival during in vitro gastric, bile and intestinal digestion (p≤0.5). Moreover, non-dairy liquids with Acetobacter xylinum manifested improved performance compared to Lactobacillus in this food environment. Therefore, the functionality of a probiotic product may not only be dependent on the type of microorganism but also the food medium. Knowledge of the above may enable the consumer in making a careful selection of a desirable food product to gain maximum health benefits.