Valorization of crop residues and animal wastes: Anaerobic co-digestion technology

To switch the over-reliance on fossil-based resources, curb environmental quality deterioration, and promote the use of renewable fuels, much attention has recently been directed toward the implementation of sustainable and environmentally benign 'waste-to-energy' technology exploiting a clean, inexhaustible, carbon-neutral, and renewable energy source, namely agricultural biomass. From this perspective, anaerobic co-digestion (AcoD) technology emerges as a potent and plausible approach to attain sustainable energy development, foster environmental sustainability, and, most importantly, circumvent the key challenges associated with mono-digestion. This review article provides a comprehensive overview of AcoD as a biochemical valorization pathway of crop residues and livestock manure for biogas production. Furthermore, this manuscript aims to assess the different biotic and abiotic parameters affecting co-digestion efficiency and present recent advancements in pretreatment technologies designed to enhance feedstock biodegradability and conversion rate. It can be concluded that the substantial quantities of crop residues and animal waste generated annually from agricultural practices represent valuable bioenergy resources that can contribute to meeting global targets for affordable renewable energy. Nevertheless, extensive and multidisciplinary research is needed to evolve the industrial-scale implementation of AcoD technology of livestock waste and crop residues, particularly when a pretreatment phase is included, and bridge the gap between small-scale studies and real-world applications.

Sustainable crop production: Highlights on economic, environmental and social life cycle thinking

Seeking multi-dimensional inclusion is one of the most global concerns of the crop production sector worldwide. Socio-eco-effectiveness or socio-eco-efficiency optimization plays a crucial role in future strategy establishment. Life cycle is a widely used approach examining economic, environmental, and social impacts. Recently, life cycle thinking approaches have been increasingly utilized to bring to light useful perceptions of the crop production processes. This study aims to apply a systematic review and prescriptive analytics to critically investigate the life cycle thinking approaches application according to sustainability pyramid aspects, life cycle thinking unicity, goal and scope variability, functional units' causality, system boundary' diversity, involved aspect' concentration, indicators, impacts categories and influencing variables distribution, as well as to define a first datasheet model and directive axis to apply per aspect and family for socio-eco-effectiveness or socio-eco-efficiency evaluation. Over 295 peer-reviewed studies from 2019 to the middle of 2023, 52 reviews and articles gathered from Web of Science and Scopus meet the criteria to be analyzed. Our inspection revealed that related reviews are few, approximately 2 %. Moving from the traditional life cycle perspective to the sustainability pyramid approach, the indicators applied by researchers were classified per aspect and family belonging. A deductive analysis was carried out to narrow the impact categories, and the influencing factors to the population's main interests: four economic (input status, resources consumption, waste, and Costs of Life Cycle), eight environmental (Climate Change, Global Warming, Ozone, Acidification, Eutrophication, Photochemical Oxidation, Abiotic Depletion, and Toxicity), and three social families (Human Toxicity, employment, and Ionizing Radiation). The results combination highlights the construction need for a directive datasheet model to address the optimizing problem under the identified families and aspects constraints, as well as to envisage the units and methods worldwide standardization's necessity for spatial-temporal studies comparison in the present, the past, and the future.

[Virtual simulation for learning cataract surgery]

INTRODUCTION

The training in phacoemulsification cataract surgery in our context requires a long learning curve for a novice surgeon starting from the observation period to the realization of the different operating stages being supervised by a senior surgeon, all under stressful conditions. Topical or locoregional anesthesia limits the communication in the operating room between the novice surgeon and his mentor; thus, increasing the risk of having more operative complications. To reduce the teaching time of cataract surgery, our department has introduced virtual simulator trainings for phacoemulsification.

PURPOSE OF THE STUDY

To assess the impact of surgical simulator training on residents' performances.

MATERIAL AND METHODS

We conducted a prospective comparative study in our department in partnership with a private ophthalmology clinic where the simulator is installed. Twelve residents were included in this study, six of them were randomly selected to participate in the phacoemulsification surgical simulator training while the others never used the simulator. The training lasted 30 hours in total. No residents had previous training in phacoemulsification. The parameters studied were: the operating time, the achievement of a circular capsulorhexis of 5-6mm in diameter and well centered, the number of capsular breaks with or without an anterior vitrectomy and finally the accumulated dissipated energy (EDC). The cataract surgery was performed on an Alcon Centurion platform.

RESULTS

In the operating room, each resident operated 25 cataracts; we compared the two user groups including the simulator and non simulator user and we noticed a statistically significant difference (P<0.05) in terms of average operating time respectively 20 minutes and 37 minutes. Regarding the realization of capsulorhexis; 22 cases of rhexis wandering and 12 poorly centred rhexis on 150 operated cataracts were identified (22.7%) in the group of residents who received no simulator training versus 10 cases in the simulator user group (6.7%). The cumulative dissipated energy (EDC) was significantly lower in the simulator user group (8.1 versus 18.7). The same is true for the rate of posterior capsular rupture, which is higher in the non-user group of simulator 37 cases (24.6%) versus 10 cases (8%) in the second group.

DISCUSSION

Ophthalmic surgery has benefited from the introduction of endo-ocular surgical simulation tools through simulators of vitreoretinal surgery and phacoemulsification; whose main role is primarily pedagogical because a simulator allows young residents to acquire dexterity and autonomy over a shortened period of time in addition to minimizing the risk of complications.

CONCLUSION

Initial learning of phacoemulsification cataract surgery should be an integral part of the virtual simulator program before moving to the real conditions of the operating room as it allows for better operative performance with a minimal complication rate.