Biodiesel-Alkaline Transesterification Process for Methyl Ester Production

The world needs to increase renewable and alternative fuel sources such as Biomass, Bioethanol, and Biodiesel to compete with fossil fuels. Biodiesel is an important renewable fuel source since it can be used in regular diesel vehicles without requiring engine modifications. Conventional biodiesel production takes around 90 min of reaction time. A longer reaction time is not suitable for commercial production. Furthermore, traditional products such as oil react with biodiesel methoxide to produce a maximum of 90% biodiesel yield. As the catalyst is not involved with the reaction, pure methanol and methoxide (methanol with KOH catalyst) are separately added to the system to enhance the pre-reaction step. By changing the methanol to methoxide ratio, biodiesel is produced, and yield is calculated. The highest yield, which is 95%, is obtained with a 5:15% methanol to methoxide ratio. The total reaction time with the new experimental procedure is only 20 min. That is a significant reduction by saving operating costs such as energy consumption. Produced biodiesel show similar properties to that of standard biodiesel.

Optimization of the qPCR temperature profile is essential for efficient and rapid detection of Sars-CoV-2

qPCR protocols should specify shorter annealing and extension times to optimize the efficacy of the target product. These specific times must be long enough for the complexes to form at the correct binding site, but if these times are too long, it can result in unspecified products. Our results show that reducing the reaction time during the second cycle can increase the specificity of the resulting product and thus reduce the total reaction time. The overall temperature profile, optimized for the target gene, shortens the detection time, allowing faster and more specific detection of the presence of the Sars-CoV-2.

Fucoidan-Coated Liposomes: A Target System to Deliver the Antimicrobial Drug Usnic Acid to Macrophages Infected with Mycobacterium tuberculosis

The present study describes the use of fucoidan, a negative sulfated polysaccharide, as a coating material for the development of liposomes targeted to macrophages infected with Mycobacterium tuberculosis. First, fucoidan was chemically modified to obtain a hydrophobized-fucoidan derivative (cholesteryl-fucoidan) using a two-step microwave-assisted (μW) method. The total reaction time was decreased from 14 hours to 1 hour while maintaining the overall yield. Cholesterylfucoidan was then used to prepare surface-modified liposomes containing usnic acid (UA-LipoFuc), an antimicrobial lichen derivative. UA-LipoFuc was evaluated for mean particle size, polydispersity index (PDI), surface charge (ζ), and UA encapsulation efficiency. In addition, a cytotoxicity study, competition assay and an evaluation of antimycobacterial activity against macrophages infected with M. tuberculosis (H37Ra) were performed. When the amount of fucoidan was increased (from 5 to 20 mg), vesicle size increased (from 168 ± 2.82 nm to 1.18 ± 0.01 μm). Changes in from +20 ± 0.41 mV for uncoated liposomes to −5.41 ± 0.23 mV for UA-LipoFuc suggested that the fucoidan was placed on the surface of the liposomes. UA-LipoFuc exhibited a lower IC50 (8.26 ± 1.11 μM) than uncoated liposomes (18.37 ± 3.34 μM), probably due to its higher uptake. UA-LipoFuc5 was internalized through the C-type carbohydrate recognition domain of the cell membrane. Finally, usnic acid, both in its free form and encapsulated in fucoidan-coated liposomes (UA-LipoFuc5), was effective against infected macrophages. Hence, this preliminary investigation suggests that encapsulated usnic acid will aid in further studies related to infected macrophages and may be a potential option for tuberculosis treatment.

Reactions under increased pressure: The reactivity of functionally substituted 3-oxo-2-arylhydrazones toward active methylene reagents in Q-tube

A one-pot two-component reaction of 3-oxo-2-arylhydrazones with active methylene nitriles under high pressure in a Q-tube safe reactor was reported. Comparison between conventional and Q-tube safe reactor-assisted synthesis of organic compounds was done by comparing total reaction time and percentage yield. The results show that the compound 5-cyano-6-oxo-1,4-diphenyl-1,6-dihydro-pyridazine-3-carboxylic acid ethyl ester (3) was synthesized within 2 h in a yield of 97%. In addition, the pyrazolo[3,4-c]pyridines 5b and 5c were obtained in yields of 93 and 95% within 1 h reaction time, respectively. The obtained results suggest that Q-tube safe reactor-assisted syntheses were led to higher product yields within very short reaction times.

Driving reaction time following periacetabular osteotomy

Introduction: Periacetabular osteotomy (PAO) is increasingly being used to treat young adults with symptomatic hip dysplasia. Currently there is a lack of evidence to guide return to driving after this procedure. This study aimed to identify the length of time required after a Periacetabular Osteotomy procedure before a patient can safely return to driving. Methods: All patients undergoing PAO were assessed for suitability for the study. Inclusion criteria were: currently driving with a valid licence; and being able to attend follow-up assessment. Baseline driving reaction time was assessed using a driving simulator preoperatively. The simulation was repeated 5 times for each patient and reaction times recorded (Thinking time, Action time and Total reaction time for braking at 30 mph). The driving simulation was repeated using the same methods at 6 weeks and 12 weeks postoperatively. Pre- and postoperative times were compared. Results: 26 patients were included (24 females, 2 males) with a mean age of 32 (range 19–50) years. The mean preoperative times were: Thinking time 0.48, Action time 0.21, Total time 0.69 seconds. At 6 weeks postoperatively, mean Action time increased to 0.26 seconds ( p = 0.012) and mean Total time increased to 0.78 seconds ( p = 0.013). By 12 weeks post procedure, there was no significant difference in reaction times compared to baseline (mean Thinking time 0.47 seconds, Action time 0.23, Total time 0.72; p > 0.05). Conclusions: Most patients may not be safe to drive at 6 weeks following PAO procedures but should be safe to drive at 12 weeks postoperatively. Individual patient factors should also be taken into consideration.

Protective Effect of Solutions Containing Polymers Associated with Fluoride and Stannous Chloride on Hydroxyapatite Dissolution

This study investigated the protective effect of experimental solutions containing 4 polymers (polyoxirane, hydroxypropylmethylcellulose [HPMC], pectin, and an amino methacrylate copolymer [AMC]) in 2 concentrations (low and high) associated or not with sodium fluoride (F; 225 ppm F^–) or sodium fluoride plus stannous chloride (FS; 800 ppm Sn²⁺) on the dissolution of hydroxyapatite crystals (HA). Deionized water was the control. The pretreated HA was added to a 0.3% citric acid solution (pH 3.8). An automatic titrant machine added aliquots of 0.1 N HCl at a rate of 28 μL/min, in a total reaction time of 5 min. Groups were compared with 2-way ANOVA and Tukey’s test, and concentrations with Student <i>t</i> test (5%). The zeta potential of the HA treated with the solutions was measured. Significant differences were found for both factors and interaction (<i>p</i> &#x3c; 0.0001). The treatments with F and FS solutions resulted in a lower amount of dissolved HA than the control. Among the polymers’ solutions, only AMC was able to reduce the amount of dissolved HA, changing the surface charge of HA to positive. AMC improved the protective effect of F, but it did not affect FS. Polyoxirane and HPMC reduced the protective potential of the FS solution. No differences were found between the concentrations of the polymers. It was concluded that F and FS reduced the amount of dissolved HA. The protective effect of the experimental solutions against HA dissolution was polymer dependent. The F effect was enhanced by its combination with AMC, but the protection of FS was impaired by polyoxirane and HPMC.

Head-to-head comparison of direct-input RT-PCR and RT-LAMP against RT-qPCR on extracted RNA for rapid SARS-CoV-2 diagnostics

SUMMARYViral pandemics, such as Covid-19, pose serious threats to human societies. To control the spread of highly contagious viruses such as SARS-CoV-2, effective test-trace-isolate strategies require population-wide, systematic testing. Currently, RT-qPCR on extracted RNA is the only broadly accepted test for SARS-CoV-2 diagnostics, which bears the risk of supply chain bottlenecks, often exaggerated by dependencies on proprietary reagents. Here, we directly compare the performance of gold standard diagnostic RT-qPCR on extracted RNA to direct input RT-PCR, RT-LAMP and bead-LAMP on 384 primary patient samples collected from individuals with suspected Covid-19 infection. With a simple five minute crude sample inactivation step and one hour of total reaction time, we achieve assay sensitivities of 98% (direct RT-PCR), 93% (bead-LAMP) and 82% (RT-LAMP) for clinically relevant samples (diagnostic RT-qPCR Ct <35) and a specificity of >98%. For direct RT-PCR, our data further demonstrate a perfect agreement between real-time and end-point measurements, which allow a simple binary classification similar to the powerful visual readout of colorimetric LAMP assays. Our study provides highly sensitive and specific, easy to implement, rapid and cost-effective alternatives to diagnostic RT-qPCR tests.

A Comparative Usability Study of Bare Hand Three-Dimensional Object Selection Techniques in Virtual Environment

Object selection is the basis of natural user–computer interaction (NUI) in a virtual environment (VE). Among the three-dimensional object selection techniques employed in virtual reality (VR), bare hand-based finger clicking interaction and ray-casting are two convenient approaches with a high level of acceptance. This study involved 14 participants, constructed a virtual laboratory environment in VR, and compared the above two finger-based interaction techniques in terms of aspects of the task performance, including the success rate, total reaction time, operational deviation, and accuracy, at different spatial positions. The results indicated that the applicable distance range of finger clicking interaction and finger ray-casting was 0.2 to 1.4 m and over 0.4 m, respectively. Within the shared applicable distance, the finger clicking interaction achieved a shorter total reaction time and higher clicking accuracy. The performance of finger clicking interaction varied remarkably at the center and edge of the horizontal field of view, while no significant difference was found among ray-casting at various horizontal azimuths. The current findings could be directly applied to the application of bare-hand interaction in VR environments.

Drivers ’reaction time research in the conditions in the real traffic

The article presents the results of research on the total reaction time of drivers in real traffic conditions. The tested driver had to react to a complex signal by performing a braking manoeuvre. The measurements were based on the author’s method combining the measurements of reaction time during the actual driving with their computer analysis. The research group consisted of 15 drivers with different seniority of driving licences. The study measured the time of perception and the time of leg transfer from the accelerator pedal to the brake pedal. The results were subjected to analysis and on its basis conclusions were formulated.

Synthetic Evaluation of Standard and Microwave-Assisted Solid Phase Peptide Synthesis of a Long Chimeric Peptide Derived from Four Plasmodium falciparum Proteins

An 82-residue-long chimeric peptide was synthesised by solid phase peptide synthesis (SPPS), following the Fmoc protocol. Microwave (MW) radiation-assisted synthesis was compared to standard synthesis using low loading (0.20 mmol/g) of polyethylene glycol (PEG) resin. Similar synthetic difficulties were found when the chimeric peptide was obtained via these two reaction conditions, indicating that such difficulties were inherent to the sequence and could not be resolved using MW; by contrast, the number of coupling cycles and total reaction time became reduced whilst crude yield and percentage recovery after purification were higher for MW radiation-assisted synthesis.