Enhancing corrosion resistance of mild steel in hydrochloric acid with Chiquita banana sap extract.

The corrosion of metals is still a huge challenge for various industries, and the pursuit of effective treatments ensures environmental sustainability. In this study, we utilized Chiquita banana sap-water extract (BSWE) to prevent mild steel from electrochemical corrosion in a 0.1 M HCl at room temperature. Corrosion resistance was assessed using various electrochemical methodologies, combining with surface characterization techniques. The results showed a high level of effectiveness when the corrosion current density decreased from 3292.67 µA cm-2 (for the sample immerged in the blank solution) to 187.33 µA cm-2 after 24 hours of immersion in the solution containing BSWE at a 2000 ppm concentration, equivalent to corrosion efficiency of 94.32%. Surface characterization revealed diminished corrosion on the inhibited steel surface due to the formation of a protective layer. X-ray photoelectron spectroscopy results demonstrated the presence of BSWE ingredients combining with iron oxides and hydroxides to form a smooth protective layer. Furthermore, theoretical calculations also indicated that the addition of BSWE can reduce steel surface damage when exposing to corrosive environment. The inhibitor based on banana sap extract can be referred to as a sustainable protective coating since it is biodegradable, abundantly available in banana plants and free of other harmful substances.

Acute Kidney Injury After Percutaneous Coronary Intervention Guided by Intravascular Ultrasound.

Purpose We investigated the impact of intravascular ultrasound guidance on reducing the incidence of contrast-induced acute kidney injury (CI-AKI) in patients undergoing percutaneous coronary intervention (PCI). Methods Ninety-nine patients were enrolled in this prospective cohort who were not randomly assigned to angiography-guided percutaneous coronary intervention or intravascular ultrasound-guided percutaneous coronary intervention. The patients were hospitalized at the Vietnam National Heart Institute - Bach Mai Hospital between 2019 and 2020. Acute kidney injury incidence during hospitalization was the primary endpoint. Results A total of 99 patients were divided into two groups: the intravascular ultrasound-guided group (33 participants) and the angiography-guided group (66 participants). The mean ± SD contrast volume of each group was 95.2 ± 37.1 mL and 133.0 ± 36.0 mL for the ultrasound-guided and angiography-guided groups, with P < 0.0001. Intravascular imaging-guided percutaneous coronary intervention (IVUS-guided PCI) was associated with reduced acute kidney injury incidence during hospitalization: 0.0% vs. 12.12% and P = 0.049. Conclusions Intravascular ultrasound is a safe imaging tool that guides percutaneous coronary intervention and significantly reduces the rate of acute kidney injury compared to angiography alone. Patients who have a high chance of experiencing acute kidney injury benefit from using intravascular ultrasound.

Tinctoric acid A-B, two new hopan-type triterpenoids from the Vietnamese lichen, Parmotrema tinctorum (Despr. ex Nyl.) hale with α-glucosidase inhibitory activity.

Two new hopan-type triterpenoids, namely tinctoric acid A-B (1-2), were isolated from the lichen Parmotrema tinctorum (Despr. ex Nyl.) Hale. Their structures were elucidated by extensive spectroscopic analyses (1D and 2D NMR). The absolute configuration at C-22 of 1 was established through DP4 probability. Compounds 1-2 were evaluated for their inhibitory activity against α-glucosidase and found to be more potent than those of positive control (acarbose, IC50 168 µM) with values IC50 74.7 and 98.2 µM, respectively. Both of these compounds interacted well with enzyme α-glucosidase MAL32 through H-bonds and hydrophobic interaction.

A novel adaptive neural network-based time-delayed estimation control for nonlinear systems subject to disturbances and unknown dynamics.

This paper presents an adaptive backstepping-based model-free control (BSMFC) for general high-order nonlinear systems (HNSs) subject to disturbances and unstructured uncertainties to enhance the system tracking performance. The proposed methodology is constructed based on the backstepping control (BSC) with radial basis function neural network (RBFNN) -based time-delayed estimation (TDE) to overcome the obstacle of unknown system dynamics. Additionally, a command-filtered (CF) approach is involved to address the complexity explosion of the BSC design. As the errors arising from approximation, new control laws are established to reduce the effects in this regard. The stability of the closed-loop system is guaranteed through the Lyapunov theorem and the superiority of the proposed methodology is confirmed through a comparative simulation with other model-free approaches.

Tinctorin, a new spiroterpenoid from the lichen Parmotrema tinctorum (Despr. ex Nyl.) Hale growing in Vietnam.

A new spiroterpenoid, namely tinctorin (1), along with one known compound, norreticulatin (2), were isolated from the lichen Parmotrema tinctorum (Despr. ex Nyl.) Hale. Their structures were elucidated by extensive spectroscopic analyses and electronic circular dichroism (ECD) calculations. The absolute configuration of 2 was established for the first time. Compound 1 was evaluated for its inhibitory activity against α-glucosidase and found to be inactive.

A Massive Renal Infarction Due to Atheroemboli: A Case Report.

The symptoms of acute renal infarction (ARI) caused by atheroemboli are vague, making it rare. Early diagnosis of renal infarction can be made through contrast-enhanced CT of the abdomen. However, diagnosing atheroemboli is more challenging. Kidney biopsy is the most accurate method to determine the cause, but it may not always be available in clinical settings. In cases where a thrombectomy is performed, white substances in thrombus aspiration or the patient's blood can suggest a diagnosis. Intervention is an effective technique, but there is controversy due to a lack of data, particularly in lobular artery infarction. We successfully treated one case using thrombus aspiration, and the specimens suggested atherosclerosis as the cause.

Preventing Risks of Infections and Medication Errors in IV therapy (PRIME): a patient safety initiative.

BACKGROUND: Two major avoidable reasons for adverse events in hospital are medication errors and intravenous therapy-induced infections or complications. Training for clinical staff and compliance to patient safety principles could address these. METHODS: Joint Commission International (JCI) consultants created a standardised, 6-month training programme for clinical staff in hospitals. Twenty-one tertiary care hospitals from across south-east Asia took part. JCI trained the clinical consultants, who trained hospital safety champions, who trained nursing staff. Compliance and knowledge were assessed, and monthly audits were conducted. RESULTS: There was an overall increase of 29% in compliance with parameters around medication preparation and vascular access device management. CONCLUSION: The programme improved safe practice around preparing medications management and managing vascular access devices. The approach could be employed as a continuous quality improvement initiative for the prevention of medication errors and infusion-associated complications.

Eumitrins I-K: three new xanthone dimers from the lichen Usnea baileyi.

In the continuing discovery and structure elucidation of natural xanthone dimers, which are still rarely reported in absolute configuration, three new xanthone dimers, eumitrins I-K (1-3) were isolated from the lichen Usnea baileyi, a rich source of natural xanthone dimers. Their structures were elucidated unambiguously by spectroscopic analyses, including high-resolution electrospray ionization mass spectrometry (HRESIMS), 1D and 2D nuclear magnetic resonance spectroscopy (1D and 2D NMR). The absolute configuration of all three compounds was established through DP4 probability and ECD calculation. All compounds revealed weak activity for their enzymatic inhibition against α-glucosidase and tyrosinase, as well as antibacterial activity.

Robust Adaptive Control Strategy for a Bidirectional DC-DC Converter Based on Extremum Seeking and Sliding Mode Control.

This paper presents a new control strategy that combines classical control and an optimization scheme to regulate the output voltage of the bidirectional converter under the presence of matched and mismatched disturbances. In detail, a control-oriented modeling method is presented first to capture the system dynamics in a common canonical form, allowing different disturbances to be considered. To estimate and compensate for unknown disturbances, an extended state observer (ESO)-based continuous sliding mode control is then proposed, which can guarantee high tracking precision, fast disturbance rejection, and chattering reduction. Next, an extremum seeking (ES)-based adaptive scheme is introduced to ensure system robustness as well as optimal control effort under different working scenarios. Finally, comparative simulations with classical proportional-integral-derivative (PID) control and constant switching gains are conducted to verify the effectiveness of the proposed adaptive control methodology through three case studies of load resistance variations, buck/boost mode switching, and input voltage variation.

Eumitrins F-H: three new xanthone dimers from the lichen Usnea baileyi and their biological activities.

The lichen Usnea baileyi is a fruticose lichen belonging to the Usnea genus. It is well known as a rich source of natural xanthone dimers and possesses various bioactivities. Nevertheless, the chemical investigation on this type of lichen is still rare as most of researches reported its components without structural elucidation. Herein, in the continuous study on this type of lichen, we further isolate xanthone dimers from the dichloromethane extract and explore three new xanthone dimers, eumitrins F - H (1 - 3). Their structures were elucidated unambiguously by spectroscopic analyses, including high resolution electrospray ionisation mass spectrometry (HRESIMS), 1 D and 2 D nuclear magnetic resonance spectroscopy (1 D and 2 D NMR), and DP4 probability. All compounds were evaluated for their enzyme inhibition against α-glucosidase, tyrosinase, and antibacterial activity. They revealed moderate antimicrobial and weak tyrosinase inhibition. For α-glucosidase inhibition, compound 3 displayed the most significant inhibitory against α-glucosidase possessing an IC50 value of 64.2 µM.

Actuator failure compensation-based command filtered control of electro-hydraulic system with position constraint.

In this article, the design and experimental evaluation of a fault-tolerant controller are introduced for a double-rod electro-hydraulic actuator subjected to actuator faults and disturbances. The internal leakage fault is captured as a bias fault, whilst the faults in servo-valve and supply failure are considered as a partial loss of effectiveness (LOE) fault. The design obstacles caused by the disturbances and bias fault are suppressed by nonlinear disturbance observers (NDO) while an asymmetric barrier Lyapunov function is used to ensure the non-violated boundary of the output position. To tackle the LOE fault, the development of an enhanced adaptive compensation technique for actuator fault-tolerant control (FTC) is then constructed. Moreover, to mitigate the "explosion of complexity" in the traditional backstepping design, the command-filtered control is utilized to elaborate the FTC scheme. It is shown by theoretical analysis that system stability is ensured under faulty conditions. Finally, simulation/experiment results and comparison studies are performed to further verify the effectiveness of the proposed approach.

Modelling quantities and qualities (Q&Q) of faecal sludge in Hanoi, Vietnam and Kampala, Uganda for improved management solutions.

The importance of faecal sludge management is gaining recognition. However, methods are still lacking to reasonably estimate the quantities and qualities (Q&Q) that need to be managed, which makes the planning for and implementing of management solutions quite difficult. The objective of this study was to collect and analyse Q&Q of faecal sludge at a citywide scale, and to evaluate whether "SPA-DET" data (=> spatially analysable - demographic, environmental and technical) could then be used as predictors of Q&Q of faecal sludge. 60 field samples and questionnaires from Hanoi and 180 from Kampala were analysed. Software tools were used in an iterative process to predict total solids (TS) and emptying frequency in both Hanoi, Vietnam and Kampala, Uganda. City-specific data could be predicted with types of "SPA-DET" data as input variables, and model performance was improved by analysing septic tanks and pit latrines separately. Individual models were built for TS concentrations and emptying frequency. In addition, a model was built across both cities for emptying frequency of septic tanks based on number of users and containment volume, indicating predictive models can be relevant for multiple cities. Number of users, containment volume, truck volume and income level were identified as the most common variables for the correction function. Results confirm the high intrinsic variability of faecal sludge characteristics, and illustrate the importance of moving beyond simple reporting of city-wide average values for estimations of Q&Q. The collected data and developed scripts have been made available for replication in future studies.

Improved Corrosion Resistance of Steel in Ethanol Fuel Blend by Titania Nanoparticles and Aganonerion polymorphum Leaf Extract.

A porous and low-density protective film on a steel surface in the corrosive environment can undergo deterioration even in the presence of organic inhibitors due to infiltration of aggressive ions into the pinholes and/or pores. This phenomenon is related to the localized corrosion that takes place even in the presence of an optimal concentration of organic corrosion inhibitors in the given medium. To overcome this issue, we have designed an organic protective film on a steel surface with the help of titania nanoparticles (TNPs) combined with an organic corrosion inhibitor derived from Aganonerion polymorphum leaf extract (APLE), all to be studied in a simulated ethanol fuel blend (SEFB). The TNPs with varied diameters and concentrations have been studied for examining their effect on the inhibition capacity of 1000 ppm APLE on the steel surface in SEFB medium using electrochemical and surface analysis techniques. Enhanced corrosion inhibition of the surficial film was observed in the presence of both the APLE inhibitor and small amounts of TNPs. A direct agreement was observed between the experimental and molecular dynamics theoretical investigations showcasing high binding energy between inhibitor molecules and steel substrates, resulting in a much higher adhesion of the protective film, good thermal stability of the adsorbent film, and electron abundance for the supply of steel substrate of inhibitor species.

Monitoring of tritium concentration in Hanoi's precipitation from 2011 to 2016.

Tritium is a radioisotope of hydrogen and a component of the water molecule. It is a marker for reservoirs such as the stratosphere, troposphere, and oceans involved in the hydrological cycle. Tritium monitoring is an essential research tool in hydro-climate, dating for water and recharge groundwater. The Isotope Hydrology Laboratory has collected monthly precipitation samples in Hanoi for tritium concentration analysis. This paper reports the tritium concentrations in precipitation in the city from 2011 to 2016. The results show that monthly tritium concentration reached a maximum of 7.07 Tritium Units (TU) in August 2011. The mean annual tritium concentration stabilized from 2.03 to 3.36 TU. It suggests that tritium in monitoring station precipitation is predominantly natural. The seasonal variation trend of 3H in precipitation at the Hanoi station is similar to those monitored at the Hong Kong station. The correlation of tritium and rainfall was also estimated.