Simulation and Modelling of Hydrogen Production from Waste Plastics: Technoeconomic Analysis.

The global energy demand is expected to increase by 30% within the next two decades. Plastic thermochemical recycling is a potential alternative to meet this tremendous demand because of its availability and high heating value. Polypropylene (PP) and polyethylene (PE) are considered in this study because of their substantial worldwide availability in the category of plastic wastes. Two cases were modeled to produce hydrogen from the waste plastics using Aspen Plus®. Case 1 is the base design containing three main processes (plastic gasification, syngas conversion, and acid gas removal), where the results were validated with the literature. On the other hand, case 2 integrates the plastic gasification with steam methane reforming (SMR) to enhance the overall hydrogen production. The two cases were then analyzed in terms of syngas heating values, hydrogen production rates, energy efficiency, greenhouse gas emissions, and process economics. The results reveal that case 2 produces 5.6% more hydrogen than case 1. The overall process efficiency was enhanced by 4.13%. Case 2 reduces the CO2 specific emissions by 4.0% and lowers the hydrogen production cost by 29%. This substantial reduction in the H2 production cost confirms the dominance of the integrated model over the standalone plastic gasification model.

Awake Craniotomy Under 3-Tesla Intraoperative Magnetic Resonance Imaging: A Retrospective Descriptive Report and Canadian Institutional Experience.

BACKGROUND: The role of high-field 3-Tesla intraoperative magnetic resonance imaging (I-MRI) during awake craniotomy (AC) has not been extensively studied. We report the feasibility and safety of AC during 3-Tesla I-MRI. METHODS: This retrospective descriptive report compared 3 groups: AC with minimal sedation and I-MRI; I-MRI-guided craniotomy under general anesthesia (GA), and; AC without I-MRI. Perioperative factors, surgical, anesthetic and radiologic complications, and postoperative morbidity and mortality were recorded. RESULTS: Overall, 85 patients are included in this report. Five of 23 patients (22%) who underwent AC with I-MRI had anesthetic complications (nausea/vomiting and conversion to GA) compared with 3 of 40 (8%) who underwent I-MRI-guided craniotomy under GA (nausea/vomiting during extubation, and arrhythmia). Intraoperative surgical complications (seizures and speech deficits) occurred in 5 patients (22%) who underwent AC and I-MRI, excessive intraoperative bleeding occurred in 2 patients (5%) who had I-MRI-guided craniotomy under GA, and 4 of 22 (18%) patients who underwent AC without I-MRI experienced neurological complications (seizures, motor deficits, and transient loss of consciousness). Eight patients (20%) who had I-MRI with GA had postoperative complications, largely neurological. The duration of surgery and anesthesia were shortest in the group of patients receiving AC without I-MRI. Seventy-three percent of the patients in this group had residual tumor postoperatively compared with 44% and 38% in those having I-MRI with AC or GA, respectively. Patients who underwent I-MRI-guided craniotomy with GA had the highest morbidity (8%) at hospital discharge. CONCLUSIONS: Our institutional experience suggests that AC under 3-Tesla I-MRI could be an option for glioma resection, although firm conclusions cannot be drawn given the limited and heterogenous nature of our data. Future multicenter trials comparing anesthetic and imaging modalities for glioma resection are recommended.

Technoeconomic Feasibility of Hydrogen Production from Waste Tires with the Control of CO2 Emissions.

The worldwide demand for energy is increasing significantly, and the landfill disposal of waste tires and their stockpiles contributes to huge environmental impacts. Thermochemical recycling of waste tires to produce energy and fuels is an attractive option for reducing waste with the added benefit of meeting energy needs. Hydrogen is a clean fuel that could be produced via the gasification of waste tires followed by syngas processing. In this study, two process models were developed to evaluate the hydrogen production potential from waste tires. Case 1 involves three main processes: the steam gasification of waste tires, water gas shift, and acid gas removal to produce hydrogen. On the other hand, case 2 represents the integration of the waste tire gasification system with the natural gas reforming unit, where the energy from the gasifier-derived syngas can provide sufficient heat to the steam methane reforming (SMR) unit. Both models were also analyzed in terms of syngas compositions, H2 production rate, H2 purity, overall process efficiency, CO2 emissions, and H2 production cost. The results revealed that case 2 produced syngas with a 55% higher heating value, 28% higher H2 production, 7% higher H2 purity, and 26% lower CO2 emissions as compared to case 1. The results showed that case 2 offers 10.4% higher process efficiency and 28.5% lower H2 production costs as compared to case 1. Additionally, the second case has 26% lower CO2-specific emissions than the first, which significantly enhances the process performance in terms of environmental aspects. Overall, the case 2 design has been found to be more efficient and cost-effective compared to the base case design.

Effect of Daytime Versus Night-time on Outcome in Patients Undergoing Emergent Neurosurgical Procedures.

BACKGROUND: Timing of neurosurgical procedures is controversial. Challenges identified with night-time surgeries include physician fatigue and sleep deprivation, and fewer staff and resources compared with daytime surgery. These might contribute to medical errors and complications, and, hence, worse patient outcomes. METHODS: This single center retrospective study of 304 patients who underwent emergent neurosurgical procedures between January 1, 2010 and December 31, 2016 included 2 groups based on the timing of surgery: daytime (7:00 AM to 6:59 PM) and night-time (7:00 PM to 6:59 AM) surgery groups. Patient demographics, diagnosis, surgical characteristics, complications, and neurological outcome were obtained from the medical records. RESULTS: There was no difference in patient demographics, intraoperative complications, and length of surgery between the 2 groups. Although there was no statistically significant difference in neurological outcome between the 2 groups at hospital discharge and 1 month postdischarge, there was a higher proportion of patients in the night-time surgical group with unfavorable neurological outcome (Glasgow Outcome Score 1 to 3) at both these times. There were differences in hospital length of stay, location of postoperative management (postanesthesia care unit or intensive care unit), midline shift, baseline Glasgow Coma Scale score, and acuity of surgery between the 2 groups. Logistic regression analysis showed that age, baseline Glasgow Coma Scale score, surgery acuity status, procedure type, and intraoperative complications influenced neurological outcome. CONCLUSIONS: This study found no difference in the rate of unfavorable neurological outcome in patients undergoing emergent neurosurgical procedures during the daytime and night-time. However, our findings cannot exclude the possibility of an association between timing of surgery and outcome given its limitations, including small sample size and omission of potentially confounding variables. Further well-designed prospective trials are warranted to confirm our findings.

A survey of burn professionals regarding the mental health services available to burn survivors in the United States and United Kingdom.

UNLABELLED: This investigation surveyed burn health professionals in the UK and US to investigate the psychosocial issues facing burn survivors and the psychological services available to them through their burns service. METHODS: One hundred and sixty six burn care professionals (132 from the United States and 34 from the United Kingdom) from 76 different hospitals (60 in the US and 16 in the UK) completed an online survey. Mental health practitioners (MHPs) answered questions regarding their psychotherapy practice with burn survivors. RESULTS: Respondents reported that psychosocial issues are common among burn survivors. Burn teams in the UK were more likely than those in the US to include psychologists, but social workers were more common in the US. Participants reported that routine screening for psychosocial issues was more common in the UK than the US, and indicated it was easier for burn survivors to access mental health care after discharge in the UK. Burn services in both countries routinely referred burn survivors to support organizations such as the Phoenix Society or Changing Faces. The preferred mental health treatment modality in the UK was psychotherapy without medications. Reported psychotropic medications use was more common in the US. MHPs had two primary orientations - eclectic and cognitive behavioral therapy. Among MHPs there was a modest tendency to favor evidence-based interventions. DISCUSSION: The provision of mental health services varies between these two countries. Creating international standards for assessing and treating psychosocial complications of burns could facilitate the improvement of burn mental health services.

The quinone-binding site of Acidithiobacillus ferrooxidans sulfide: quinone oxidoreductase controls both sulfide oxidation and quinone reduction.

Sulfide:quinone oxidoreductase (SQR) is a peripheral membrane enzyme that catalyzes the oxidation of sulfide and the reduction of ubiquinone. Ubiquinone binds to a conserved hydrophobic domain and shuttles electrons from a noncovalent flavin adenine dinucleotide cofactor to the membrane-bound quinone pool. Utilizing the structure of decylubiquinone bound to Acidithiobacillus ferrooxidans SQR, we combined site-directed mutagenesis and kinetic approaches to analyze quinone binding. SQR can reduce both benzoquinones and naphthoquinones. The alkyl side-chain of ubiquinone derivatives enhances binding to SQR but limits the enzyme turnover. Pentachlorophenol and 2-n-heptyl-4-hydroxyquinoline-N-oxide are potent inhibitors of SQR with apparent inhibition constants (Ki) of 0.46 µmol·L(-1) and 0.58 µmol·L(-1), respectively. The highly conserved amino acids surrounding the quinone binding site play an important role in quinone reduction. The phenyl side-chains of Phe357 and Phe391 sandwich the benzoquinone head group and are critical for quinone binding. Importantly, conserved amino acids that define the ubiquinone-binding site also play an important role in sulfide oxidation/flavin reduction.