80 research outputs found
Is immersion in mint oil or apple vinegar solution a valid antifungal approach for acrylic soft liners?
Objectives: In-vitro assessment of the validity of immersion in mint oil or apple vinegar solutions as antifungal approach for acrylic soft liners. Materials and methods: Sixty disc-shaped specimens: 9mm in diameter and 2mm in length, and sixty cylinders: 12.5mm in diameter and 20mm in length of Vertex-Dental Heat-cured acrylic soft liner were prepared for antifungal activity and resilience measurements respectively. Specimens were divided into three groups; twenty in each, for immersion in mint oil, apple vinegar and distilled water (control). The groups were divided into four subgroups, five in each, for the different immersion periods: one day, one week, three weeks and six weeks. For each group, the daily immersion protocol was 8 h of immersion in the testing solution followed by 16 h in artificial saliva. This was repeated for each immersion period. Antifungal activity was assessed using disc diffusion method by measuring the inhibition zone for each disc twice: after 24 and 48 h incubation. Modulus of resilience was determined using a universal testing machine, where a stress-strain curve was obtained for each specimen and the area under the elastic portion of the curve was calculated. Results: A significantly higher antifungal activity was revealed following immersion in mint oil compared to apple vinegar solution. The immersion period was a significant variable for the antifungal activity measured after 24 h following immersion in either solution whereas it was an insignificant variable for the antifungal activity measured after 48 h following immersion in apple vinegar solution. A significant reduction in the antifungal activity was noted as the incubation period was increased from 24 to 48 h except after six weeks immersion in apple vinegar solution. Modulus of resilience of the acrylic soft liner was adversely affected by immersion in mint oil solution for more than one day and in apple vinegar solution for more than one week. Conclusions: Mint oil and Apple vinegar represent possible natural antifungal immersion solutions for acrylic soft liner provided that the immersion protocol is implemented properly
Experimental and theoretical evaluations on Oleuropein as a natural origin corrosion inhibitor for copper in acidic environment
none5siCopper corrosion in acidic cleaning solutions is a major worry for heat exchangers. Corrosion inhibitors derived from natural sources might be a viable option. The isolation of Oleuropein compound from olive leaf and investigation of its anticorrosion potential for copper in 1.0 M H2SO4 solution are reported here. All experimental results from LC-MS, FT-IR, 1H and 13C-NMR characterizations support the molecular structure of Oleuropein. Electrochemical and gravimetric tests were used to evaluate the corrosion inhibition capabilities of Oleuropein. According to polarization investigation, Oleuropein is a mixed-type inhibitor. Oleuropein's inhibitory efficacy increases with concentration, attaining an optimum value (98.92%) at 100 mg L-1. At high temperatures, Oleuropein can be considered an efficient inhibitor. Thermodynamic variables for the activation operation and copper dissolution were computed and addressed as well. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) examinations revealed that Oleuropein produced an outer layer on the copper surface, shielding it from severe acid damage. Quantum chemical simulations were employed to propose molecular explanations for Oleuropein's inhibitory actions.Deyab, M A; Mohsen, Q; Bloise, E; Lazzoi, M R; Mele, GDeyab, M A; Mohsen, Q; Bloise, E; Lazzoi, M R; Mele,
Synthesis and antibacterial activity of 3-arylidene chromen-2, 4-dione derivatives
Abstract: Derivatives of 3-arylidene chromen-2, 4-dione 1 were synthesized to be used as a starting material for synthesizing some new fused heterocyclic compounds containing coumarin moiety. When compounds 1 reacted with hydrazine derivatives, hydroxylamine hydrochloride, urea, thiourea, semicarbazide and thiosemicarbazide it gave the corresponding compounds 2-5. Compound 4a, b reacted with methyl iodide in DMF and K2CO3 at room temperature to afford the corresponding 6a, b. All these compounds were screened InVitro for their antibacterial activity
EvaluaciĂłn De La Influencia De Las Condiciones De Fondo De Pozo En El Deterioro De Un Acero API P110, En Ambientes Simulados Del Proceso De CombustiĂłn In Situ, Por GravimetrĂa Y EIS
RESUMEN Dada la gran cantidad de consumo del petróleo como recurso energético, tiene por consecuencia una diminución en el crudo existente a nivel mundial, la explotación del crudo pesado surge como nueva alternativa de extracción que se deja a un lado debido a las dificultades asociadas a su procesamiento. Por lo tanto el proceso de combustión in situ, es un método de extracción que facilita la producción de este tipo de crudo, pues generan un aumento en la producción a expensas de un aumento de los costos asociados a mantenimiento, pues a las condiciones operacionales se favorecen fenómenos como la corrosión de los diferentes materiales involucrados en el proceso, pues están expuestos a atmosferas de sulfuro de hierro (H2S), entre otros gases; a temperaturas y presiones elevadas, lo cual promueve la corrosión y los fenómenos de Sulfide stress cracking. Adicionalmente, los materiales se ven afectados por la acidez y la cantidad de impurezas presentes en el crudo. Por lo anterior se evaluó el comportamiento del acero API P110 expuesto a crudo pesado con diferentes contenidos de azufre (0.5 - 1.5 % en peso), TAN (2.28 - 6.84 g KOH/g crudo) a elevadas temperaturas (190 -250 °C) y presiones (8.96x106 - 11.72x106 Pa), ya que se pueden presentar estas condiciones en el proceso de extracción por combustión in situ en fondos de pozo. Se encontró que el principal mecanismo de corrosión en estas condiciones es la corrosión por sulfidación cuyos principales productos de corrosión son el FeS y óxido de hierro (Fe3O4)
Chemical Additives for Corrosion Control in Desalination Plants
The addition of chemical additives has been considered as a standard
operation in water treatment systems. This chapter discusses the chemical
additives used for the control of corrosion in desalination systems. Specifically,
corrosion inhibitors for various metallurgies, biocides, and oxygen scavengers
are covered. The pros and cons of the additive chemicals have been
highlighted. The need to utilize green corrosion inhibitors based on plants and
ionic liquids materials have been emphasized. This class of materials are
environmentally friendly, cheap, and readily available
Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study
Background: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. // Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. // Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. // Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030
Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study
Summary
Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally.
Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies
have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of
the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income
countries globally, and identified factors associated with mortality.
Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to
hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis,
exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a
minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical
status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary
intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause,
in-hospital mortality for all conditions combined and each condition individually, stratified by country income status.
We did a complete case analysis.
Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital
diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal
malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome
countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male.
Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3).
Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income
countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups).
Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome
countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries;
p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients
combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11],
p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20
[1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention
(ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety
checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed
(ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of
parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65
[0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality.
Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome,
middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will
be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger
than 5 years by 2030
Stainless steel bipolar plate coated with polyaniline/Zn-Porphyrin composites coatings for proton exchange membrane fuel cell
Abstract The proton exchange membrane fuel cells are the promising sustainable energy sources. The present study focuses on the enhancement the fuel cell performance and the protection of the stainless steel bipolar plate from the corrosion using polyaniline/Zn-Porphyrin composites coatings. The electrochemical properties (polarization and impedance) of the coated 303 stainless steel in 1.0 M H2SO4 solution have been evaluated. The coated 303 stainless steel by new composites exhibits the excellent anti-corrosion activity towards corrosive fuel cell electrolyte. The polyaniline/Zn-Porphyrin composite gives an excellent performance by adding 1.0% of Zn-Porphyrin. This composite improves the output power of the fuel cell
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