Biocompounds from wastewater-grown microalgae: a review of emerging cultivation and harvesting technologies.

Microalgae biomass has attracted attention as a feedstock to produce biofuels, biofertilizers, and pigments. However, the high production cost associated with cultivation and separation stages is a challenge for the microalgae biotechnology application on a large scale. A promising approach to overcome the technical-economic limitations of microalgae production is using wastewater as a nutrient and water source for cultivation. This strategy reduces cultivation costs and contributes to valorizing sanitation resources. Therefore, this article presents a comprehensive literature review on the status of microalgae biomass cultivation in wastewater, focusing on production strategies and the accumulation of valuable compounds such as lipids, carbohydrates, proteins, fatty acids, and pigments. This review also covers emerging techniques for harvesting microalgae biomass cultivated in wastewater, discussing the advantages and limitations of the process, as well as pointing out the main research opportunities. The novelty of the study lies in providing a detailed analysis of state-of-the-art and potential advances in the cultivation and harvesting of microalgae, with a special focus on the use of wastewater and implementing innovative strategies to enhance productivity and the accumulation of compounds. In this context, the work aims to guide future research concerning emerging technologies in the field, emphasizing the importance of innovative approaches in cultivating and harvesting microalgae for advancing knowledge and practical applications in this area.

Physical and chemical characterization and pollution index applied in the assessment of the polluting potential of leachate from urban landfills.

During the operation of the landfills, leachate should be managed with caution to avoid possible negative environmental impacts. Considering this, the present study aims to evaluate the relationship between different variables in the leachate composition and elucidate the transformation processes through which this effluent passes during the landfill's period of operation. The study was conducted with eight sanitary landfills from the state of Minas Gerais, in southeastern Brazil, and used descriptive statistical analysis, principal component analysis (PCA), correlation analysis, and calculation of the leachate pollution index (LPI). The biochemical oxygen demand (BOD5)/chemical oxygen demand (COD) ratio was between 0.20 and 0.60. We also observed a significant correlation of 0.45 between Cl- and N-NH4+, which reflects the biological degradation processes that contribute to the presence of both variables. The PCA showed that inorganic variables and organic matter dominated the first component, with coefficients above 0.65, indicating the importance of those variables in determining the general data variability. The LPI values were between 15.26 and 25.97, with BOD5, COD, and N-NH4+ having sub-indexes above 35, being the main variables that increase the pollution potential of the leachate. On the other hand, trace metals present sub-indexes below 7 due to precipitation caused by increased pH and the characteristics of the waste discarded in landfills. The study provides essential information regarding the landfill leachate characteristics and its variation over time, which can contribute to the definition of treatment technologies for this affluent in different scenarios.

Treatment outcome of oropharyngeal squamous cell carcinoma through propensity score analysis.

According to an extensive database, the Objective is to compare surgical versus non-surgical treatment through Propensity Score (PS) for patients with Oropharyngeal Squamous Cell Carcinoma (OPSCC). METHODS: We retrospectively evaluated epidemiological data from 8075 patients with OPSCC diagnosed between 2004 and 2014 and used PS matching to analyze possible prognostic factors for its outcomes with regression analyses. RESULTS: Cox multiple regression analysis to study survival after PS matching shows that type of treatment was associated with death with a hazard ratio of 1.753 (p<0.05) of non-surgical treatment. However, it was not associated with recurrence (p>0.05). In the surgical treatment group, overall survival was 79.9% at one year, 36.4% at five years, and 20.5% at ten years. Disease-free survival was 90.1%, 64.8%, and 56.0% at 1, 5, and 10-years, respectively. In the non-surgical treatment group, overall survival was 60.6% at one year, 21.8% at five years, and 12.7% at ten years. Disease-free survival was 90.8%, 67.2%, and 57.8% at 1, 5, and 10-years, respectively. CONCLUSION: Patients in the surgical treatment group had better outcomes related to survival. Recurrence is associated with the survival of OPSCC cancer. Recurrence-free survival is similar to both treatments. LEVEL OF EVIDENCE: 2C.

Treatment outcome of oropharyngeal squamous cell carcinoma through propensity score analysis

Abstract According to an extensive database, the Objective is to compare surgical versus nonsurgical treatment through Propensity Score (PS) for patients with Oropharyngeal Squamous Cell Carcinoma (OPSCC). Methods: We retrospectively evaluated epidemiological data from 8075 patients with OPSCC diagnosed between 2004 and 2014 and used PS matching to analyze possible prognostic factors for its outcomes with regression analyses. Results: Cox multiple regression analysis to study survival after PS matching shows that type of treatment was associated with death with a hazard ratio of 1.753 (p < 0.05) of non-surgical treatment. However, it was not associated with recurrence (p> 0.05). In the surgical treatment group, overall survival was 79.9% at one year, 36.4% at five years, and 20.5% at ten years. Disease-free survival was 90.1%, 64.8%, and 56.0% at 1, 5, and 10-years, respectively. In the non-surgical treatment group, overall survival was 60.6% at one year, 21.8% at five years, and 12.7% at ten years. Disease-free survival was 90.8%, 67.2%, and 57.8% at 1, 5, and 10-years, respectively. Conclusion: Patients in the surgical treatment group had better outcomes related to survival. Recurrence is associated with the survival of OPSCC cancer. Recurrence-free survival is similar to both treatments. Level of evidence: 2C.

Prognostic factors in oropharyngeal squamous cell carcinoma in the state of São Paulo, Brazil: 10-year follow-up

Abstract Objective: To descriptively analyze the epidemiological data, clinical stage, and outcomes of oropharyngeal squamous cell carcinoma in the state of São Paulo, Brazil, and to estimate the influence of clinical stage and treatment type on overall and disease-free survival. Methods: We retrospectively analyzed epidemiological data from the São Paulo Cancer Center Foundation database relative to patients with oropharyngeal squamous cell carcinoma diagnosed between 2004 and 2014 in the state of São Paulo. Univariate and multivariate Cox regression analyses were performed to assess factors associated with the outcomes. A forward stepwise selection procedure was used. Survival curves were estimated by the Kaplan-Meier method and compared by the Gehan-Breslow-Wilcoxon test. Results: A total of 8075 individuals with oropharyngeal squamous cell carcinoma were identified. Of these, 86.3% were diagnosed at an advanced stage and 13.7% at an early stage. Only 27.2% of patients were treated surgically, whereas 57.5% were treated medically. Patients undergoing surgery had longer overall survival than those receiving medical treatment in both early- and advanced-stage oropharyngeal squamous cell carcinoma. However, there was no significant difference in disease-free survival between surgical and medical treatment. Conclusion: No significant difference in disease-free survival between medical and surgical treatment suggests similar complete remission rates with both approaches. Patients receiving medical treatment had shorter overall survival, which may be due to complications from chemotherapy and radiotherapy. However, we cannot confirm this relationship based on the data provided by the São Paulo Cancer Center Foundation. Prospective studies are warranted to assess whether the lower overall survival rate in patients receiving medical treatment is secondary to complications from chemotherapy and radiotherapy. Level of evidence: 2C.

Secondary tracheoesophageal puncture with a flexible transillumination device: a new technique and its outcomes

Abstract Objectives: This study aims to describe a new secondary tracheoesophageal puncture technique with voice prosthesis insertion under local anesthesia with a low-cost device and evaluate its outcome. Methods: With a transoral flexible transillumination device of aluminum of 2.3 mm with fiberoptic light, the esophagus's anterior wall is visualized through the tracheostomy. A tracheoesophageal fistula is made with a blade and passed through the fistula. Then a bent trocar is introduced into the lumen using the device as a guidewire. Once in the lumen, a thin guide wire is passed through up to the mouth. The voice prosthesis is positioned with retrograde insertion. Then, the patient is discharged without hospitalization. Results: 15 patients submitted to this technique had a successful surgical outcome. There were no complications as pneumothorax, esophageal perforation, bleeding, or hospitalization. Conclusion: The new device is feasible under local anesthesia.

Prognostic factors in oropharyngeal squamous cell carcinoma in the state of São Paulo, Brazil: 10-year follow-up.

OBJECTIVE: To descriptively analyze the epidemiological data, clinical stage, and outcomes of oropharyngeal squamous cell carcinoma in the state of São Paulo, Brazil, and to estimate the influence of clinical stage and treatment type on overall and disease-free survival. METHODS: We retrospectively analyzed epidemiological data from the São Paulo Cancer Center Foundation database relative to patients with oropharyngeal squamous cell carcinoma diagnosed between 2004 and 2014 in the state of São Paulo. Univariate and multivariate Cox regression analyses were performed to assess factors associated with the outcomes. A forward stepwise selection procedure was used. Survival curves were estimated by the Kaplan-Meier method and compared by the Gehan-Breslow-Wilcoxon test. RESULTS: A total of 8075 individuals with oropharyngeal squamous cell carcinoma were identified. Of these, 86.3% were diagnosed at an advanced stage and 13.7% at an early stage. Only 27.2% of patients were treated surgically, whereas 57.5% were treated medically. Patients undergoing surgery had longer overall survival than those receiving medical treatment in both early- and advanced-stage oropharyngeal squamous cell carcinoma. However, there was no significant difference in disease-free survival between surgical and medical treatment. CONCLUSION: No significant difference in disease-free survival between medical and surgical treatment suggests similar complete remission rates with both approaches. Patients receiving medical treatment had shorter overall survival, which may be due to complications from chemotherapy and radiotherapy. However, we cannot confirm this relationship based on the data provided by the São Paulo Cancer Center Foundation. Prospective studies are warranted to assess whether the lower overall survival rate in patients receiving medical treatment is secondary to complications from chemotherapy and radiotherapy. LEVEL OF EVIDENCE: 2C.

The potential of algae and aquatic macrophytes in the pharmaceutical and personal care products (PPCPs) environmental removal: a review.

The presence of emerging contaminants, such as pharmaceuticals and personal care products (PPCPs), in aquatic environments has received increasing attention in the last years due to the various possible impacts on the dynamics of the natural environment and human health. In global terms, around 771 active pharmaceutical substances or their transformation products have been detected at levels above their respective detection limit. Additionally, 528 different compounds have been detected in 159 countries. Seeking to overcome potential ecotoxicological problems, several studies have been conducted using different technologies for PPCPs removal. Recently, the use of macro, microalgae, and aquatic macrophytes has been highlighted due to the excellent bioremediation capacity of these organisms and easy acclimatization. Thus, the present review aims to outline a brief and well-oriented scenario concerning the knowledge about the bioremediation alternatives of PPCPs through the use of macro, microalgae, and aquatic macrophytes. The characteristics of PPCPs and the risks of these compounds to the environment and human health are also addressed. Moreover, the review indicates the opportunities and challenges for expanding the use of biotechnologies based on algae and aquatic macrophytes, such as studies dedicated to relate the operational criteria of these biotechnologies with the main PPCPs removal mechanisms. Finally, algae and macrophytes can compose green and ecological biotechnologies for wastewater treatment, having great contribution to PPCPs removal.

Sentinel lymph node biopsy for early squamous cell carcinoma of the lip and oral cavity: Real-world experience in Brazil.

BACKGROUND: This study aimed to evaluate the accuracy and oncological results of sentinel lymph node biopsy in patients with early lip and oral cavity squamous cell carcinoma (SCC) in a real-world scenario. METHODS: Retrospective study including seven Brazilian centers. RESULTS: Four-hundred and seven cN0 patients were accrued for 20 years. The rate of occult metastasis was 23.1% and 22 patients (5.4%) had regional failure. We found, for 5 years of follow-up, 85.3% of regional recurrence-free survival; 77.1% of disease-free survival; 73.7% of overall survival; and 86.7% of disease-specific survival. The rate of false-negative cases was 5.4%. CONCLUSION: In a real-world scenario, sentinel lymph node biopsy for patients with SCC of the lip and oral cavity proved feasible in different settings and to be oncologically safe, with similar rates of occult lymph node metastasis and false-negative cases, when compared to elective neck dissection, and with similar long-term survival to that reported historically.

Secondary tracheoesophageal puncture with a flexible transillumination device: a new technique and its outcomes.

OBJECTIVES: This study aims to describe a new secondary tracheoesophageal puncture technique with voice prosthesis insertion under local anesthesia with a low-cost device and evaluate its outcome. METHODS: With a transoral flexible transillumination device of aluminum of 2.3 mm with fiberoptic light, the esophagus's anterior wall is visualized through the tracheostomy. A tracheoesophageal fistula is made with a blade and passed through the fistula. Then a bent trocar is introduced into the lumen using the device as a guidewire. Once in the lumen, a thin guide wire is passed through up to the mouth. The voice prosthesis is positioned with retrograde insertion. Then, the patient is discharged without hospitalization. RESULTS: 15 patients submitted to this technique had a successful surgical outcome. There were no complications as pneumothorax, esophageal perforation, bleeding, or hospitalization. CONCLUSION: The new device is feasible under local anesthesia.

Evaluation of reduction of external load of total phosphorus and total suspended solids for rehabilitation of urban lakes.

Urban lakes provide important services to cities, but they suffer from en-vironmental problems, mainly resulting from degradation of the watershed. Rehabilitation of degraded lakes is based on the recovery of water quality and reduction of external pollution, the latter usually taking priority. The Lagoa da Pampulha (LP) is an artificial lake located in Belo Horizonte, Minas Gerais - Brazil, that has suffered eutrophication and silting for decades and has been undergoing rehabilitation for some years. The objective of this study was to evaluate the importance of sanitary, environmental and urban improvements implemented in the LP watershed. For this purpose, total phosphorus (TP) and total suspended solid (TSS) loads transported to LP, between 2016 and 2017, obtained from hydrological and water quality monitoring data, were estimated. Additionally, simulations were carried out using the Storm Water Management Model (SWMM) to evaluate TP and TSS loads in hypothetical scenarios. The conservative scenario proposed a reduction of 50 % in sanitary sewage discharge to water courses and an increase of 30 % and 10 % in the urban area and non-vegetated soil, respectively, in the watershed. In an op-timistic scenario, a reduction of 95 % in sewage discharge and a reduction of 50 % in non-vegetated soils was proposed. According to the results obtained, between October 2016 and September 2017, about 38 tons of TP and 3000 tons of TSS were transported into LP. The results of the SWMM simulations indicated high loads entering the lake, ranging from about 23,000 to 13,000 ton/year for TP and from 3200 to 2400 ton/year for TSS, in actual and optimistic scenario respectively. Despite presenting significant reductions, of up to 60 % for TP and 25 % for TSS, the loads transported to LP remained high even in the most optimistic scenario, indicating that implementation of the evaluated improvements only not sufficient to guarantee rehabilitation of the lake, and must be associated with other measures.

Evaluation of high rate ponds operational and design strategies for algal biomass production and domestic wastewater treatment.

This study evaluated the effect of high rate ponds (HRPs) depth on algal biomass production during domestic wastewater treatment. HRPs were evaluated for 20, 30, and 40 cm depths, with and without CO2 supplementation. In addition, 40 cm deep HRP with ultraviolet (UV) pre-disinfection was evaluated. The concentration of chlorophyll-a as a function of time for each evaluated condition was represented by logistic models that were after submitted to cluster analysis. The 20 cm HRPs presented higher chlorophyll-a concentration, reaching a maximum of 5.8 and 4.3 mg L-1, in the HRPs with and without CO2 addition, respectively. Ammonia nitrogen and soluble phosphorus were greater removed in shallower HRPs. The addition of CO2 influenced the nutrient removal processes, optimizing nutrient recovery by biomass assimilation. HRP configuration did not influence organic matter removal (~40% of removal efficiency in all HRPs), predominant microalgae genera (Chlorella sp. and Scenedesmus), and E. coli inactivation (removal of ~2 log units), except for the 20 cm HRP without CO2 that had removal of 4 log units due to high pH values. For HRPs with CO2 addition and UV pre-disinfection, the models for 40 cm were grouped together with those obtained for 30 cm HRPs, indicating the same behavior for chlorophyll-a production as a function of time. Thus, it can be concluded that the evaluated strategies represent alternatives for reducing HRP area requirements. Moreover, results may represent advancement and major contributions for HRP design criteria.

Simulation System of Electric-Powered Wheelchairs for Training Purposes.

For some people with severe physical disabilities, the main assistive device to improve their independence and to enhance overall well-being is an electric-powered wheelchair (EPW). However, there is a necessity to offer users EPW training. In this work, the Simcadrom is introduced, which is a virtual reality simulator for EPW driving learning purposes, testing of driving skills and performance, and testing of input interfaces. This simulator uses a joystick as the main input interface, and a virtual reality head-mounted display. However, it can also be used with an eye-tracker device as an alternative input interface and a projector to display the virtual environment (VE). Sense of presence, and user experience questionnaires were implemented to evaluate this version of the Simcadrom in addition to some statistical tests for performance parameters like: total elapsed time, path following error, and total number of commands. A test protocol was proposed and, considering the overall results, the system proved to simulate, very realistically, the usability, kinematics, and dynamics of a real EPW in a VE. Most subjects were able to improve their EPW driving performance in the training session. Furthermore, all skills learned are feasible to be transferred to a real EPW.

Correction: Effects of conversion of native cerrado vegetation to pasture on soil hydro-physical properties, evapotranspiration and streamflow on the Amazonian agricultural frontier.

[This corrects the article DOI: 10.1371/journal.pone.0179414.].

Biomass production in high rate ponds and hydrothermal liquefaction: Wastewater treatment and bioenergy integration.

Against the worldwide energy crisis and climate change, new forms of energy generation have been investigated. Among the possibilities, microalgae are considered potential feedstock for biofuels production. However, there are still important challenges to overcome. In this context, the integration of biomass cultivation and the treatment of different types of wastewater can represent a source of nutrients and water, with the additional benefit of reducing the discharge of pollutant loads into water bodies. The wastewater grown biomass is composed by a microorganism consortium. These microorganisms can develop important symbiotic relationships for the optimization of biomass production. However, the success of algal biomass cultivation in effluents also involves the development of efficient reactors, which ranges from design criteria to operational parameters. High rate ponds are the most suitable reactors for such a purpose, within the context of a wastewater treatment plant. In this reactor, the addition of CO2 is an important parameter for pH control and, consequently, will influence nutrient assimilation. Another relevant operational parameter is the pond depth, which will have a major role in radiation availability along the water column. With respect to the energy use of the biomass, hydrothermal liquefaction (HTL) represents an interesting alternative for wastewater grown biomass, since the process does not require complete drying of the biomass, its bio-oil production efficiency is not necessarily attached to the lipid content and may present a positive energy balance. In addition, the possibility of using the HTL by-products, especially the water soluble products, in the context of a biorefinery, represents a route for nutrient recycling, residue minimization, and cost reduction.

A review of biochemical and thermochemical energy conversion routes of wastewater grown algal biomass.

Microalgae are recognized as a potential source of biomass for obtaining bioenergy. However, the lack of studies towards economic viability and environmental sustainability of the entire production chain limits its large-scale application. The use of wastewaters economizes natural resources used for algal biomass cultivation. However, desirable biomass characteristics for a good fuel may be impaired when wastewaters are used, namely low lipid content and high ash and protein contents. Thus, the choice of wastewaters with more favorable characteristics may be one way of obtaining a more balanced macromolecular composition of the algal biomass and therefore, a more suitable feedstock for the desired energetic route. The exploration of biorefinery concept and the use of wastewaters as culture medium are considered as the main strategic tools in the search of this viability. Considering the economics of overall process, direct utilization of wet biomass using hydrothermal liquefaction or hydrothermal carbonization and anaerobic digestion is recommended. Among the explored routes, anaerobic digestion is the most studied process. However, some main challenges remain as little explored, such as a low energy pretreatment and suitable and large-scale reactors for algal biomass digestion. On the other hand, thermochemical conversion routes offer better valorization of the algal biomass but have higher costs. A biorefinery combining anaerobic digestion, hydrothermal carbonization and hydrothermal liquefaction processes would provide the maximum possible output from the biomass depending on its characteristics. Therefore, the choice must be made in an integrated way, aiming at optimizing the quality of the final product to be obtained. Life cycle assessment studies are critical for scaling up of any algal biomass valorization technique for sustainability. Although there are limitations, suitable integrations of these processes would enable to make an economically feasible process which require further study.

Radiative forcing of methane fluxes offsets net carbon dioxide uptake for a tropical flooded forest.

Wetlands are important sources of methane (CH4 ) and sinks of carbon dioxide (CO2 ). However, little is known about CH4 and CO2 fluxes and dynamics of seasonally flooded tropical forests of South America in relation to local carbon (C) balances and atmospheric exchange. We measured net ecosystem fluxes of CH4 and CO2 in the Pantanal over 2014-2017 using tower-based eddy covariance along with C measurements in soil, biomass and water. Our data indicate that seasonally flooded tropical forests are potentially large sinks for CO2 but strong sources of CH4 , particularly during inundation when reducing conditions in soils increase CH4 production and limit CO2 release. During inundation when soils were anaerobic, the flooded forest emitted 0.11 ± 0.002 g CH4 -C m-2  d-1 and absorbed 1.6 ± 0.2 g CO2 -C m-2  d-1 (mean ± 95% confidence interval for the entire study period). Following the recession of floodwaters, soils rapidly became aerobic and CH4 emissions decreased significantly (0.002 ± 0.001 g CH4 -C m-2  d-1 ) but remained a net source, while the net CO2 flux flipped from being a net sink during anaerobic periods to acting as a source during aerobic periods. CH4 fluxes were 50 times higher in the wet season; DOC was a minor component in the net ecosystem carbon balance. Daily fluxes of CO2 and CH4 were similar in all years for each season, but annual net fluxes varied primarily in relation to flood duration. While the ecosystem was a net C sink on an annual basis (absorbing 218 g C m-2 (as CH4 -C + CO2 -C) in anaerobic phases and emitting 76 g C m-2 in aerobic phases), high CH4 effluxes during the anaerobic flooded phase and modest CH4 effluxes during the aerobic phase indicate that seasonally flooded tropical forests can be a net source of radiative forcings on an annual basis, thus acting as an amplifying feedback on global warming.

Energy recovery in high rate algal pond used for domestic wastewater treatment.

High rate algal pond (HRAP) was evaluated according to its energy potential and productivity by two rates, net energy ratio (NER) and specific biomass productivity. All energy inputs were calculated according to one HRAP with pre-ultraviolet disinfection treating anaerobic domestic sewage. The outputs were calculated for two energetic pathways: lipid and biogas production for the raw biomass (RB) and biomass after lipid extraction. The non-polar lipid content in dry biomass was 7.6%, reaching a daily lipid productivity of 0.2 g/m2·day and the biogas production potential was 0.20 m3/kg solids. For the biomass after lipid extraction, the biogas production reached 2.6 m3/kg solids. NER values of 10-3 for the RB were similar for lipids and biogas routes. The specific biomass productivity was 0.7 mg/kJ. For the residual biomass, after lipid extraction, NER value was 10-2 for the integrated route (lipids + biogas) and the specific biomass productivity of the extracted biomass was 0.4 mg/kJ. The best energetic pathway was to integrate both lipids and biogas route.