EFFECTIVE ALKALINE PEROXIDE OXIDATION PRETREATMENT OF SHEA TREE SAWDUST FOR THE PRODUCTION OF BIOFUELS: KINETICS OF DELIGNIFICATION AND ENZYMATIC CONVERSION TO SUGAR AND SUBSEQUENT PRODUCTION OF ETHANOL BY FERMENTATION USING Saccharomyces cerevisiae

Shea tree sawdust delignification kinetic data during alkaline peroxide pretreatment were investigated at temperatures of 120 °C, 135 °C, and 150 °C. The activation energy during delignification was 76.4 kJ/mol and the Arrhenius constant was calculated as 8.4 x 106 per min. The reducing sugar yield for the treated to the untreated biomass was about 22-fold. Enzymatic hydrolysis conditions studied were; time (72 h and 96 h), substrate concentration (20, 30, 40, and 50 g/L), and enzyme loadings (10, 25, 40, 50 FPU/g dry biomass), which showed the optimum conditions of 96 h, 40 g/L, and 25 FPU/g dry biomass at 45 °C hydrolysis temperature. At the optimized enzymatic hydrolysis conditions, the reducing sugar yield was 416.32 mg equivalent glucose/g treated dry biomass. After 96 h fermentation of treated biomass, the ethanol obtained at 2% effective cellulose loading was 12.73 g/L. Alkaline peroxide oxidation pretreatment and subsequent enzymatic hydrolysis improved the ethanol yield of the biomass

Utilization of lignocellulosic waste for ethanol production: Enzymatic digestibility and fermentation of pretreated shea tree sawdust

Enzymatic hydrolysis and fermentation methods were evaluated on alkaline peroxide pretreated shea tree sawdust conversion to ethanol. Optimum pretreatment conditions of 120 oC reaction temperature, 30 min reaction time, and 20 mL L−1 of water hydrogen peroxide concentration (1%(v/v)H2O2) solubilized 679 g kg−1 of hemicellulose and 172 g kg−1 of lignin. 617 g kg−1 cellulose was retained in the solid fraction. The maximum yield of reducing sugar with optimized enzyme loadings by two enzyme preparations (cellulase and β-glucosidase) was 165 g kg−1 of dry biomass. The ethanol yield was 7.35 g L−1 after 72 h incubation period under the following conditions: 2% cellulose loading, enzyme concentration was 25 FPU (g cellulose)−1 loading, yeast inoculums was 10% (v/v), 32 oC, and pH 4.8. The pretreatments gave information about the hindrances caused by lignin presence in lignocellulosic materials and that hemicelluloses are better hydrolyzed than lignin, thereby enhancing enzymatic digestibility of the sawdust materia

Towards the Design of a Synchronous Virtual Learning System

The field of education has undoubtedly been affected by the penetrating influence of information and communication technology, characterized by improved access to the internet, and the increasing use of computing devices. However, education in Africa generally and specifically in Nigeria and other developing countries still face a 21st Century challenge in making education available and accessible to all. To this end therefore, this paper presents a conceptual approach, as to how tailor made e-learning services could be realized and integrated with a real time video conference server and any existing learning management system in order to facilitate a synchronous virtual learning environment in making education accessible and available to both remote students (distance learning students) and onsite users in Universities and other related educational institutes. It proposes a functional framework to exemplify educational services such as file sharing to enhance collaboration, a digital resource center for retrieval of both free and paid relevant academic resource. A conference room for real time classroom participation which learning platform should provide in order to enhance both teaching and learning performance of course instructors and their students respectively is also proposed. It provides an operational design which describes how custom made e-learning portal integrated with an Open source Video Conference server could be realized, in facilitating a synchronous virtual learning service. Furthermore, it proposes a Virtual Learning Network architecture to show how both remote and onsite students could optimize quality network access in realizing these electronic learning services

Hydrogen peroxide and lime based oxidative pretreatment of wood waste to enhance enzymatic hydrolysis for a biorefinery: Process parameters optimization using response surface methodology

Response surface methodology (RSM) was adopted for the optimization of process variables in the alkaline peroxide oxidation (APO) pretreatment of Vitellaria paradoxa sawdust based on central composite design (CCD) experiments. A 23 five level CCD with central and axial points was used to develop a statistical model for the optimization of process variables. Maximum response for the pretreatment was obtained when applying the optimum values for temperature (150 �C), time (45 min), and 1% (v/v) H2O2. At the optimum conditions, up to 70% of the initial hemicellulose was removed in treatments, which also caused some delignification (up to 11% of the initial lignin was removed), whereas cellulose was almost quantitatively retained in the solid phase. Alkaline peroxide assisted wet air oxidation (APAWAO) pretreatment at the optimum conditions resulted in enrichment up to 60% cellulose content along with solubilization of 80% hemicellulose and 17% of lignin initially present in the raw sawdust. Reducing sugars yield after 72 h enzymatic hydrolysis of pretreated biomass at optimized APO conditions was 177.89 mg equivalent glucose g�1 dry biomass. Addition of 10 bar air pressure at the optimized pretreatment conditions increased the sugars yield to 263.49 mg equivalent glucose g�1 dry biomass

Optimization of pretreatment conditions using full factorial design and enzymatic convertibility of shea tree sawdust

In this study alkaline wet air oxidation (WAO), alkaline peroxide assisted wet air oxidation (APAWAO), and enzymatic hydrolysis methods were evaluated for conversion of wood residue (sawdust) to reducing sugars. Cellulose content, hemicellulose solubilization, and lignin removal forWAOpretreatment conditions were optimized by statistical analysis using a 23-full factorial design with reaction temperature, air pressure, and reaction time as the process parameters. An optimum WAO condition of 170 �C, 1.0 MPa, 10 min was predicted and experimentally validated to give 518 g kg-1 cellulose content, 580 g kg-1 hemicellulose solubilization, and 171 g kg-1 lignin removal in the solid fraction. About 7 g L-1 reducing sugars was detected in the pretreated liquid fraction. Presoaking the dry raw biomass for 24 h in H2O2 followed by wet air oxidation (APAWAO) at the optimized conditions resulted in enrichment up to 683 g kg-1 cellulose content in the solid fraction along with solubilization of 789 g kg-1 hemicellulose and 280 g kg-1 lignin removal. The yield of reducing sugars from WAO optimized conditions by two enzyme preparations (cellulase and b-glucosidase) was 131mgg-1 of dry substrate, while the APAWAO yielded 274mgg-1. Pretreatments used in this study showed to have a disrupting effect on the lignocellulosic biomass, making the treated materials accessible for enzymatic hydrolysis. The combination of presoaking inH2O2 before WAO pretreatment and enzymatic hydrolysis was found to give the highest sugar yield

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Towards the Design of a Synchronous Virtual Learning System

The field of education has undoubtedly been affected by the penetrating influence of information and communication technology, characterized by improved access to the internet, and the increasing use of computing devices. However, education in Africa generally and specifically in Nigeria and other developing countries still face a 21st Century challenge in making education available and accessible to all. To this end therefore, this paper presents a conceptual approach, as to how tailor made e-learning services could be realized and integrated with a real time video conference server and any existing learning management system in order to facilitate a synchronous virtual learning environment in making education accessible and available to both remote students (distance learning students) and onsite users in Universities and other related educational institutes. It proposes a functional framework to exemplify educational services such as file sharing to enhance collaboration, a digital resource center for retrieval of both free and paid relevant academic resource. A conference room for real time classroom participation which learning platform should provide in order to enhance both teaching and learning performance of course instructors and their students respectively is also proposed. It provides an operational design which describes how custom made e-learning portal integrated with an Open source Video Conference server could be realized, in facilitating a synchronous virtual learning service. Furthermore, it proposes a Virtual Learning Network architecture to show how both remote and onsite students could optimize quality network access in realizing these electronic learning services