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Microalgae-based technology is widely utilized in wastewater treatment and resource recovery. However, the practical implementation of microalgae-based technology is hampered by the difficulty in separating microalgae from treated water due to the low density of microalgae. This review is designed to find the current status of the development and utilization of microalgae biogranulation technology for better and more cost-effective wastewater treatment. This review reveals that the current trend of research is geared toward developing microalgae-bacterial granules. Most previous works were focused on studying the effect of operating conditions to improve the efficiency of wastewater treatment using microalgae-bacterial granules. Limited studies have been directed toward optimizing operating conditions to induce the secretion of extracellular polymeric substances (EPSs), which promotes the development of denser microalgae granules with enhanced settling ability. Likewise, studies on the understanding of the EPS role and the interaction between microalgae cells in forming granules are scarce. Furthermore, the majority of current research has been on the cultivation of microalgae-bacteria granules, which limits their application only in wastewater treatment. Cultivation of microalgae granules without bacteria has greater potential because it does not require additional purification and can be used for border applications.
The most recent development in microalgae biogranulation research is highlighted.Factors affecting microalgae granule development are discussed for the first time.Duration to develop granules is a crucial aspect that needs further research.Cultivation of single-species microalgae for rapid harvesting needs more attention.
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Microalgae are promising alternatives to mitigate atmospheric CO2 owing to their fast growth rates, resilience in the face of adversity and ability to produce a wide range of products, including food, feed supplements, chemicals, and biofuels. However, to fully harness the potential of microalgae-based carbon capture technology, further advancements are required to overcome the associated challenges and limitations, particularly with regards to enhancing CO2 solubility in the culture medium. This review provides an in-depth analysis of the biological carbon concentrating mechanism and highlights the current approaches, including species selection, optimization of hydrodynamics, and abiotic components, aimed at improving the efficacy of CO2 solubility and biofixation. Moreover, cutting-edge strategies such as gene mutation, bubble dynamics and nanotechnology are systematically outlined to elevate the CO2 biofixation capacity of microalgal cells. The review also evaluates the energy and economic feasibility of using microalgae for CO2 bio-mitigation, including challenges and prospects for future development.
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Dióxido de Carbono , Microalgas , Hidrodinámica , Biocombustibles , BiomasaRESUMEN
The COVID-19 pandemic has had a profound psychological impact on our frontline healthcare workers. Throughout the entire second COVID-19 wave at one major tertiary hospital in Melbourne Australia, longitudinal qualitative data between perioperative staff members, and analyses of intrapersonal changes were reported. Inductive analysis of three open-ended questions generated four major themes: Organisational Response to the Pandemic, Psychological Impact, Changes in Feelings of Support Over Time and Suggestions for Changes. Understanding the challenges, perception and suggestions from this longitudinal study allows us to provide a range of support services and interventions to minimise the long-term negative psychological impact and be better prepared should another similar situation arises again.
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COVID-19 , Humanos , Estudios Longitudinales , Pandemias , Estudios Prospectivos , Victoria , Personal de SaludRESUMEN
OBJECTIVE: To evaluate a relatively new half-face-piece powered air-purifying respirator (PAPR) device called the HALO (CleanSpace). We assessed its communication performance, its degree of respiratory protection, and its usability and comfort level. DESIGN AND SETTING: This simulation study was conducted at the simulation center of the Royal Melbourne Hospital. PARTICIPANTS: In total, 8 voluntary healthcare workers participated in the study: 4 women and 4 men comprising 3 nursing staff and 5 medical staff. METHODS: We performed the modified rhyme test, outlined by the National Institute for Occupational Safety and Health (NIOSH), for the communication assessment. We conducted quantitative fit test and simulated workplace protection factor studies to assess the degree of respiratory protection for participants at rest, during, and immediately after performing chest compression. We also invited the participants to complete a usability and comfort survey. RESULTS: The HALO PAPR met the NIOSH minimum standard for speech intelligibility, which was significantly improved with the addition of wireless communication headsets. The HALO provided consistent and adequate level of respiratory protection at rest, during and after chest compression regardless of the device power mode. It was rated favorably for its usability and comfort. However, participants criticized doffing difficulty and perceived communication interference. CONCLUSIONS: The HALO device can be considered as an alternative to a filtering face-piece respirator. Thorough doffing training and mitigation planning to improve the device communication performance are recommended. Further research is required to examine its clinical outcomes and barriers that may potentially affect patient or healthcare worker safety.
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Exposición Profesional , Dispositivos de Protección Respiratoria , Masculino , Humanos , Femenino , Personal de Salud , Ventiladores Mecánicos , Comunicación , Exposición Profesional/prevención & controlRESUMEN
OBJECTIVES: To compare the accuracy of monitoring personal protective equipment (PPE) donning and doffing process between an artificial intelligent (AI) machine collaborated with remote human buddy support system and an onsite buddy, and to determine the degree of AI autonomy at the current development stage. DESIGN AND SETTING: We conducted a pilot simulation study with 30 procedural scenarios (15 donning and 15 doffing, performed by one individual) incorporating random errors in 55 steps. In total, 195 steps were assessed. METHODS: The human-AI machine system and the onsite buddy assessed the procedures independently. The human-AI machine system performed the assessment via a tablet device, which was positioned to allow full-body visualization of the donning and doffing person. RESULTS: The overall accuracy of PPE monitoring using the human-AI machine system was 100% and the overall accuracy of the onsite buddy was 99%. There was a very good agreement between the 2 methods (κ coefficient, 0.97). The current version of the AI technology was able to perform autonomously, without the remote human buddy's rectification in 173 (89%) of 195 steps. It identified 67.3% of all the errors independently. CONCLUSIONS: This study provides preliminary evidence suggesting that a human-AI machine system may be able to serve as a substitute or enhancement to an onsite buddy performing the PPE monitoring task. It provides practical assistance using a combination of a computer mirror, visual prompts, and verbal commands. However, further studies are required to examine its clinical efficacy with a diverse range of individuals performing the donning and doffing procedures.
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Inteligencia Artificial , Control de Infecciones , Humanos , Control de Infecciones/métodos , Personal de Salud , Equipo de Protección Personal , Proyectos PilotoRESUMEN
This study aims to establish an efficient pretreatment method that facilitates the conversion of sugars from macroalgae wastes, Eucheuma cottonii residues (ECRs) during hydrolysis and subsequently enhances l-lactic acid (L-LA) production. Hence, ultrasonic-assisted molten salt hydrates (UMSHs) pretreatment was proposed to enhance the accessibility of ECRs to hydrolyze into glucose through dilute acid hydrolysis (DAH). The obtained hydrolysates were employed as the substrate in producing L-LA by separate hydrolysis and fermentation (SHF). The maximum glucose yield (97.75 %) was achieved using UMSHs pretreated ECRs with 40 wt% ZnCl2 at 80 °C for 2 h and followed with DAH. The optimum glucose to L-LA yield obtained for SHF was 90.08 % using 5 % (w/w) inoculum cell densities of B. coagulans ATCC 7050 with yeast extract (YE). A comparable performance (89.65 %) was obtained using a nutrient combination (lipid-extracted Chlorella vulgaris residues (CVRs), vitamin B3, and vitamin B5) as a partial alternative for YE.
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The extensive growth of energy and plastic demand has raised concerns over the depletion of fossil fuels. Moreover, the environmental conundrums worldwide integrated with global warming and improper plastic waste management have led to the development of sustainable and environmentally friendly biofuel (bioethanol) and biopolymer (lactic acid, LA) derived from biomass for fossil fuels replacement and biodegradable plastic production, respectively. However, the high production cost of bioethanol and LA had limited its industrial-scale production. This paper has comprehensively reviewed the potential and development of third-generation feedstock for bioethanol and LA production, including significant technological barriers to be overcome for potential commercialization purposes. Then, an insight into the state-of-the-art hydrolysis and fermentation technologies using macroalgae as feedstock is also deliberated in detail. Lastly, the sustainability aspect and perspective of macroalgae biomass are evaluated economically and environmentally using a developed cascading system associated with techno-economic analysis and life cycle assessment, which represent the highlights of this review paper. Furthermore, this review provides a conceivable picture of macroalgae-based bioethanol and lactic acid biorefinery and future research directions that can be served as an important guideline for scientists, policymakers, and industrial players.
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BACKGROUND: Flooding the surgical field with dry cold CO
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Procedimientos Quirúrgicos Cardíacos , Insuflación , Adulto , Dióxido de Carbono , Procedimientos Quirúrgicos Cardíacos/efectos adversos , Procedimientos Quirúrgicos Electivos , Humanos , Humedad , Insuflación/efectos adversos , Insuflación/métodosRESUMEN
OBJECTIVE: This longitudinal study examined changes in psychological outcomes of perioperative frontline healthcare workers at one of Australia's most COVID-19 affected hospitals, following the surge and decline of a pandemic wave. METHOD: A single-centred longitudinal online survey was conducted between 26 May and 17 November 2020. Recruitment was via poster advertisement and email invitation. The survey was sent out every 4 weeks, resulting in seven time-points. RESULTS: In total, 385 survey results were analysed from 193 staff (about 64% response rate), 72 (37%) of whom completed the survey more than once. The prevalence of moderate-to-severe anxiety and depressive symptoms peaked at 27% and 25%, respectively, during the pandemic surge. Up to 35% displayed post-traumatic stress disorder (PTSD) symptoms. Although not statistically significant, the trend of depressive and PTSD symptoms worsened over time, especially among females and anaesthetic/surgical trainees, despite subsidence of the pandemic curve. Technicians and anaesthetic/scrub nurses were the at-risk groups with worst psychological outcomes. CONCLUSION: We found persistent mental health impacts on frontline perioperative HCWs despite subsidence of the pandemic wave. Further research is needed to determine the extent and trajectory of such impacts with larger sample sizes to determine generalisability to frontline HCWs in general.
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COVID-19 , Pandemias , Australia/epidemiología , Atención a la Salud , Depresión/epidemiología , Femenino , Personal de Salud/psicología , Hospitales Públicos , Humanos , Estudios Longitudinales , SARS-CoV-2RESUMEN
Hydrothermal carbonization (HTC) provides a promising alternative to valorize food waste digestate (FWD) and avoid disposal issues. Although hydrochar derived from FWD alone had a low calorific content (HHV of 13.9 MJ kg-1), catalytic co-HTC of FWD with wet lignocellulosic biomass (e.g., wet yard waste; YW) and 0.5 M HCl exhibited overall superior attributes in terms of energy recovery (22.7 MJ kg-1), stable and comprehensive combustion behaviour, potential nutrient recovery from process water (2-fold higher N retention and 129-fold higher P extraction), and a high C utilization efficiency (only 2.4% C loss). In contrast, co-HTC with citric acid provided â¼3-fold higher autogenous pressure, resulting in a superior energy content of 25.0 MJ kg-1, but the high C loss (â¼74%) compromised the overall environmental benefits. The results of this study established a foundation to fully utilize FWD and YW hydrochar for bioenergy application and resource recovery from the process water.
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Alimentos , Eliminación de Residuos , Carbono , Nutrientes , TemperaturaRESUMEN
The synthesis of Janus nanosheets using κ-carrageenan (κ-Ca) as a green template endows a greener and more straightforward method compared to traditional approaches of using wax template. We hypothesize that the hydrogen bonding interaction between κ-Ca and graphene oxide (GO) allows partial masking of GO's single facet, paving the way for the asymmetric modification of the exposed surface. GO is first encapsulated within the porous hydrogel matrix formed by κ-Ca to isolate one of the facets. The exposed surface was then selectively hydrophobized to produce an amphiphilic asymmetrically modified graphene oxide (AMGO). The properties of AMGO synthesized under different κ-Ca/GO ratios were studied. The κ-Ca/GO interactions and the properties of GO and AMGO were investigated and characterized. AMGO was successfully produced with a yield of 90.37 % under optimized synthesis conditions. The separation of κ-Ca and AMGO was conducted without organic solvents, and the κ-Ca could be subsequently recovered. Furthermore, the porous hydrogel matrix formed by κ-Ca and GO exhibited excellent shape-retaining properties with high thermal tolerance of up to 50 °C. Given these benefits, this newly developed method endows sustainability and open the possibility of formulating more flexible material synthesis protocols.
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Grafito , Carragenina , Hidrogeles , Enlace de HidrógenoRESUMEN
To suffice the escalating global energy demand, microalgae are deemed as high potential surrogate feedstocks for liquid fuels. The major encumbrance for the commercialization of microalgae cultivation is due to the high costs of nutrients such as carbon, phosphorous, and nitrogen. Meanwhile, the organic-rich anaerobic digestate which is difficult to be purified by conventional techniques is appropriate to be used as a low-cost nutrient source for the economic viability and sustainability of microalgae production. This option is also beneficial in terms of reutilize the organic fraction of solid waste instead of discarded as zero-value waste. Anaerobic digestate is the side product of biogas production during anaerobic digestion process, where optimum nutrients are needed to satisfy the physiological needs to grow microalgae. Besides, the turbidity, competing biological contaminants, ammonia and metal toxicity of the digestate are also potentially contributing to the inhibition of microalgae growth. Thus, this review is aimed to explicate the feasibility of utilizing the anaerobic digestate to cultivate microalgae by evaluating their potential challenges and solutions. The proposed potential solutions (digestate dilution and pre-treatment, microalgae strain selection, extra organics addition, nitrification and desulfurization) corresponding to the state-of-the-art challenges are applicable as future directions of the research.
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Microalgas , Anaerobiosis , Biocombustibles , Nutrientes , FósforoRESUMEN
The development of an efficient third-generation L-lactic acid (L-LA) production process from Eucheuma denticulatum extract (EDE) was achieved in this study. Microwave-assisted dilute acid hydrolysis (MADAH) and microwave-assisted hydrothermal hydrolysis (MAHTH) were chosen as the hydrolysis of EDE for the objective of increasing galactose yield. Single-factor optimization of hydrolysis of the EDE was studied, MADAH had high performance in galactose production relative to MAHTH, in which the yield and optimal conditions for both processes were 50.7% (0.1 M H2SO4, 120 °C for 25 min) and 47.8% (0 M H2SO4,160 °C for 35 min), respectively. For fermentation, the optimal L-LA yield was achieved at the inoculum cell density of 4% (w/w) Bacillus coagulans ATCC 7050 with 89.4% and 6% (w/w) Lactobacillus acidophilus LA-14 with 87.6%. In addition, lipid-extracted Chlorella vulgaris residues (CVRs) as co-nutrient supplementation increased the relative abundance of B. coagulans ATCC 7050, thus benefiting L-LA production.
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Chlorella vulgaris , Algas Marinas , Fermentación , Hidrólisis , Ácido Láctico , Microondas , Extractos VegetalesRESUMEN
BACKGROUND: The rapid spread of the novel coronavirus (COVID-19) has presented immeasurable challenges to health care workers who remain at the frontline of the pandemic. A rapidly evolving body of literature has quantitatively demonstrated significant psychological impacts of the pandemic on health care workers. However, little is known about the lived experience of the pandemic for frontline medical staff. OBJECTIVE: This study aimed to explore the qualitative experience of perioperative staff from a large trauma hospital in Melbourne, Australia. METHODS: Inductive thematic analysis using a critical realist approach was used to analyze data from 9 semistructured interviews. RESULTS: Four key themes were identified. Hospital preparedness related to the perceived readiness of the hospital to respond to the pandemic and encompassed key subthemes around communication of policy changes, team leadership, and resource availability. Perceptions of readiness contributed to the perceived psychological impacts of the pandemic, which were highly varied and ranged from anger to anxiety. A number of coping strategies were identified in response to psychological impacts which incorporated both internal and external coping mechanisms. Finally, adaptation with time reflected change and growth over time, and encompassed all other themes. CONCLUSIONS: While frontline staff and hospitals have rapidly marshalled a response to managing the virus, relatively less consideration was seen regarding staff mental health in our study. Findings highlight the vulnerability of health care workers in response to the pandemic and reinforce the need for a coordinated approach to managing mental health.
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A green approach using hydrogen peroxide (H2O2) to intensify the fuel properties of spent coffee grounds (SCGs) through torrefaction is developed in this study to minimize environmental pollution. Meanwhile, a neural network (NN) is used to minimize bulk density at different combinations of operating conditions to show the accurate and reliable model of NN (R2 = 0.9994). The biochar produced from SCGs torrefied at temperatures of 200-300 °C, duration of 30-60 min, and H2O2 concentrations of 0-100 wt% is examined. The results reveal that the higher heating value (HHV) of biochar increases with rising temperature, duration, or H2O2 concentration, whereas the bulk density has an opposite trend. The HHV, ignition temperature, and bulk density of biochar from torrefaction at 230 °C for 30 min with a 100 wt% H2O2 solution (230-100%-TSCG) are 27.00 MJâkg-1, 292 °C, and 120 kgâm-3, respectively. This HHV accounts for a 29% improvement compared to that of untorrefied SCG. The contact angle (126°), water activity (0.51 aw), and moisture content (7.69%) of the optimized biochar indicate that it has higher resistance against biodegradation, and thereby can be stored longer. Overall, H2O2 is a green treatment additive for SCGs solid fuel. This study has successfully produced biochar with greater HHV and low bulk density at low temperatures. The green additive development can effectively reduce environmental pollutants and upgrade wastes into resources, and achieve "3E", namely, environmental (non-polluting green additives), energy (biofuel), and circular economy (waste upgrade). In addition, the produced biochar has great potential in the fields of bioadsorbents and soil amendments.
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Café , Peróxido de Hidrógeno , Carbón Orgánico , Contaminación AmbientalRESUMEN
N95 particulate respirator masks are currently recommended for all healthcare workers who care for patients with suspected or confirmed coronavirus disease (COVID-19) when performing aerosol-generating procedures. The protection provided by N95 particulate respirator masks is dependent on the filter's efficiency and seal quality. In this prospective randomised crossover study, we conducted the user seal check and the quantitative fit test on two readily available duckbill models of N95 masks, the Halyard Fluidshield® N95 (Halyard, Alpharetta, GA, USA) and the BSN Medical ProShield® N-95 (BSN Medical, Mount Waverley, Victoria) particulate respirator masks. We recruited a total of 96 anaesthetic staff, of whom 26% were of South-East Asian ethnicity. We found that both types of masks provided reasonably high fit test pass rates among our participants and there was no significant difference between the two brands (77% for the Fluidshield and 65% for the ProShield, P = 0.916). Ninety-two percent of the participants could find at least one well-fitted mask among these two types of masks. We also demonstrated that the user seal check had low accuracy and low concordance (kappa coefficient of 0.16 for the Fluidshield and 0.08 for the ProShield) when compared to the quantitative fit test, and hence was not a reliable method to test seal quality.
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COVID-19 , Exposición Profesional , Estudios Cruzados , Humanos , Máscaras , Estudios Prospectivos , SARS-CoV-2 , Ventiladores MecánicosRESUMEN
Managing plastic waste remains an urgent environmental concern and switching to biodegradable plastics can reduce the dependence on depleting fossil fuels. This study emphasises the efficacy of macroalgae wastes, Eucheuma denticulatum residues (EDRs), as potential alternate feedstock to produce l-lactic acid (l-LA), the monomer of polylactic acid, through fermentation. An innovative environmental friendly strategy was explored in this study to develop a glucose platform from EDRs: pretreatment with microwave-assisted autohydrolysis (MAA) applied to enhance enzymatic hydrolysis of EDRs. The results indicate that MAA pretreatment significantly increased the digestibility of EDRs during the enzymatic hydrolysis process. The optimum pretreatment conditions were 120 °C and 50 min, resulting in 96.5% of enzymatic digestibility after 48 h. The high l-LA yield of 98.6% was obtained using pretreated EDRs and supplemented with yeast extract. The energy analysis implies that MAA pretreatment could further improve the overall energy efficiency of the process.
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Rhodophyta , Algas Marinas , Fermentación , Hidrólisis , Ácido LácticoRESUMEN
The accumulation of conventional petroleum-based polymers has increased exponentially over the years. Therefore, algae-based biopolymer has gained interest among researchers as one of the alternative approaches in achieving a sustainable circular economy around the world. The benefits of microalgae biopolymer over other feedstock is its autotrophic complex to reduce the greenhouse gases emission, rapid growing ability with flexibility in diverse environments and its ability to compost that gives greenhouse gas credits. In contrast, this review provides a comprehensive understanding of algae-based biopolymer in the evaluation of microalgae strains, bioplastic characterization and bioplastic blending technologies. The future prospects and challenges on the algae circular bioeconomy which includes the challenges faced in circular economy, issues regard to the scale-up and operating cost of microalgae cultivation and the life cycle assessment on algal-based biopolymer were highlighted. The aim of this review is to provide insights of algae-based biopolymer towards a sustainable circular bioeconomy.
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Compostaje , Gases de Efecto Invernadero , Microalgas , Biocombustibles , BiopolímerosRESUMEN
Microalgae-based biodiesel has gained widespread interest as an alternative energy source. Low-cost microalgae harvesting technologies are important for economically feasible biodiesel production. This study investigated, for the first time, the impact of adaptation period and height to diameter (H/D) ratio of a reactor on the growth and self-flocculation of microalgae, without the addition of bacteria. Six reactors were grouped into three sets of experiments, and each reactor was operated for 30 days at similar operating conditions (volume exchange ratio = 25% and settling time = 30 min). In set 1, two 8-L reactors, H5a (H/D ratio: 5) and H8a (H/D ratio: 8), were operated under batch operation. In set 2, reactors H5b and H8b were operated as sequential batch reactors (SBRs) without an adaptation period. In set 3, the reactors H5c and H8c were operated as SBRs with an adaptation period. The findings showed a threefold improvement in biomass productivity for the higher H/D ratio (H8c) and a reduction in biomass loss for microalgae. The H8c reactor exhibited 95% settling efficiency within 5 days, in comparison to 30 days for the H5c reactor. This study demonstrated that a higher H/D ratio and the introduction of an adaptation period in SBR operation positively influences growth and self-flocculation of enriched mixed microalgae culture.
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Microalgas , Bacterias , Biocombustibles , Biomasa , Reactores Biológicos , FloculaciónRESUMEN
This study aims to derive regenerated cellulose (RC) from lignin/hemicellulose-free Eucheuma cottonii for its independent stabilization of Pickering emulsion. The RC exhibits a fibrillar morphology with diameters ranging from 17 to 157 nm and stabilizes paraffin oil-Pickering emulsions without any co-stabilizer. It was found that the emulsion stability, viscosities and viscoelasticity correlate positively with RC concentration. All emulsion samples depict gel-like behavior. Under different oil fraction at a constant RC concentration, anomalies were found in emulsion properties. This can be attributed to the aggregating behavior of RC at the oil-water interface, the degree of gel-like structure formation due to materials interaction within the emulsion system, and the variations of microscopic droplet cluster interactions under shear condition. The emulsions portrayed excellent robustness against harsh salinity, high temperature and extreme pH fluctuation. Hence, these findings had elucidated the plausibility of macroalgae-derived RC in enhanced oil recovery application.