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1.
Nat Commun ; 14(1): 7045, 2023 Nov 03.
Article in English | MEDLINE | ID: mdl-37923791

ABSTRACT

Removal of trace CO impurities is an essential step in the utilization of Hydrogen as a clean energy source. While various solutions are currently employed to address this challenge, there is an urgent need to improve their efficiency. Here, we show that a bead-structured Mg, Cu, and Ce-based sorbent, Mg13CuCeOx, demonstrates superior removal capacity of trace CO from H2 with high stability. The incorporation of Mg boosts sorption performance by enhancing the porous structure and Cu+ surface area. Remarkably, compared to existing pelletized sorbents, Mg13CuCeOx exhibits 15.5 to 50 times greater equilibrium capacity under pressures below 10 Pa CO and 31 times longer breakthrough time in removing 50 ppm CO in H2. Energy-efficient oxidative regeneration using air at 120 °C allows its stable sorption performance over 20 cycles. Through in-situ DRIFTS analysis, we elucidate the reaction mechanism that Mg augments the surface OH groups, promoting the formation of bicarbonate and formate species. This study highlights the potential of MgCuCeOx sorbents in advancing the hydrogen economy by effectively removing trace CO from H2.

2.
J Am Chem Soc ; 145(2): 888-897, 2023 01 18.
Article in English | MEDLINE | ID: mdl-36598425

ABSTRACT

The oxidation of aldehyde is one of the fundamental reactions in the biological system. Various synthetic procedures and catalysts have been developed to convert aldehydes into corresponding carboxylic acids efficiently under ambient conditions. In this work, we report the oxidation of aldehydes by a mononuclear manganese(III) iodosylbenzene complex, [MnIII(TBDAP)(OIPh)(OH)]2+ (1), with kinetic and mechanistic studies in detail. The reaction of 1 with aldehydes resulted in the formation of corresponding carboxylic acids via a pre-equilibrium state. Hammett plot and reaction rates of 1 with 1°-, 2°-, and 3°-aldehydes revealed the electrophilicity of 1 in the aldehyde oxidation. A kinetic isotope effect experiment and reactivity of 1 toward cyclohexanecarboxaldehyde (CCA) analogues indicate that the reaction of 1 with aldehyde occurs through the rate-determining C-H bond activation at the formyl group. The reaction rate of 1 with CCA is correlated to the bond dissociation energy of the formyl group plotting a linear correlation with other aliphatic C-H bonds. Density functional theory calculations found that 1 electrostatically interacts with CCA at the pre-equilibrium state in which the C-H bond activation of the formyl group is performed as the most feasible pathway. Surprisingly, the rate-determining step is characterized as hydride transfer from CCA to 1, affording an (oxo)methylium intermediate. At the fundamental level, it is revealed that the hydride transfer is composed of H atom abstraction followed by a fast electron transfer. Catalytic reactions of aldehydes by 1 are also presented with a broad substrate scope. This novel mechanistic study gives better insights into the metal oxygen chemistry and would be prominently valuable for development of transition metal catalysts.


Subject(s)
Iodobenzenes , Manganese , Manganese/chemistry , Oxidation-Reduction , Electron Transport
3.
Int J Nurs Stud ; 136: 104375, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36327680

ABSTRACT

BACKGROUND: Speaking up about patient safety concerns is critical when bedside nurses encounter unsafe situations. Training programs that encourage nurses' speaking up behavior have been introduced, but there is limited evidence regarding whether such training leads to behavior change or improves patient safety. OBJECTIVE: The aim of this review was to identify the effectiveness of speak-up training programs for clinical nurses, focusing on program content and outcomes. DESIGN: A scoping review was conducted using the Joanna Briggs Institute methodology and reported according to the Cochrane and Preferred Reporting Items for Systematic Review and Meta-Analyses Extension for Scoping Reviews guidelines. METHODS: This study used bibliographic databases of PubMed, Embase, PsycINFO, Scopus, ProQuest Dissertations and Theses Global for the English language, and NDSL, KCI, RISS, KISS, and DBpia for the Korean language. The literature search used a combination of keywords and subject headings related to speak-up training programs for nurses or any type of nurse training program with an assertiveness component. Training outcomes were evaluated according to the 4-level Kirkpatrick model. RESULTS: A total of 4808 references were retrieved, of which 21 articles were selected. These 21 studies were conducted in different parts of the world and published from 1981 to 2020. Speak-up training primarily increased some degree of nurses' levels of assertiveness and speak-up behavior, and also led to secondary outcomes such as job stress, work motivation, and communication conflicts. Most studies (n = 19) applied traditional training formats which consisted of multi-session lectures and practice, whereas three studies applied new methodologies such as high-fidelity simulations and online learning. According to the Kirkpatrick model, five studies assessed reactions to speak-up training (level 1), all studies evaluated learning as a result of training (level 2), two studies measured the effect of speak-up training on nurses' behavior (level 3), and one study evaluated nurses' results (level 4) while no studies evaluated patient-level outcomes. CONCLUSIONS: Speak-up training for nurses can improve their levels of assertiveness or speak-up behaviors. Despite inconsistent or mixed findings, speak-up training has the potential to improve nurses' psychological well-being, leading to positive organizational performance. New training methods are directed at specialized education for clinical situations. Future speak-up training should consist of training programs based on real clinical situations in which team members participate together to comprehensively evaluate the effect of training on behavioral changes of health professionals as well as patient safety.


Subject(s)
Nurses , Occupational Stress , Humans , Clinical Competence , Communication , Health Personnel , Patient Safety
4.
Article in English | MEDLINE | ID: mdl-34200352

ABSTRACT

The incidence of osteoporosis is increasing as the population ages, as is the need to manage and prevent it. Adolescence is the period when the fastest development of bone mass takes place. Increasing adolescents' maximum bone mass and avoiding the risk factors for its loss are effective for preventing osteoporosis. This study investigated the factors influencing adolescents' bone mineral density (BMD). The participants were 126 middle- and high-school students from Gangwon-do; 47.6% (n = 60) were male, with an average age of 15 (range 12-18) years of age. It was found that age, carbonated beverages, snacks, and calcium supplements were variables that showed significant differences in adolescents' BMD. Additionally, through correlation analysis, it was found that height, weight, body mass index (BMI), body water, protein, minerals, body fat mass, and skeletal muscle mass were correlated with BMD. Multiple regression analysis identified age, calcium supplements, BMI, body fat mass, and skeletal muscle mass as BMD-associated factors. These results show that adolescents' BMD is higher with lower body fat mass, higher BMI and skeletal muscle mass, and a higher intake of calcium supplements.


Subject(s)
Body Composition , Bone Density , Adolescent , Body Mass Index , Child , Habits , Humans , Life Style , Male
5.
Ind Health ; 42(1): 83-7, 2004 Jan.
Article in English | MEDLINE | ID: mdl-14964623

ABSTRACT

A 25-year-old man, a field operator in a petroleum refinery was found unconscious. He was exposed to hydrogen sulfide and presented with Glasgow Coma Score of 5, severe hypoxemia on arterial blood gas analysis, normal chest radiography, and normal blood pressure. On hospital day 7, his mental state became clear, and neurologic examination showed quadriparesis, profound spasticity, increased tendon reflexes, abnormal Babinski response, and bradykinesia. He was also found to have decreased memory, attention deficits and blunted affect, which suggested general cognitive dysfunction, but which improved soon. MRI scan showed abnormal signals in both basal ganglia and motor cortex, compatible with clinical findings of motor dysfunction.


Subject(s)
Cognition Disorders/chemically induced , Hydrogen Sulfide/poisoning , Occupational Exposure/adverse effects , Psychomotor Disorders/chemically induced , Adult , Glasgow Coma Scale , Humans , Magnetic Resonance Imaging , Male , Neuropsychological Tests , Petroleum
6.
Korean J Parasitol ; 41(4): 189-96, 2003 Dec.
Article in English | MEDLINE | ID: mdl-14699259

ABSTRACT

In order to evaluate the possible roles of secretory proteases in the pathogenesis of amoebic keratitis, we purified and characterized a serine protease secreted by Acanthamoeba lugdunensis KA/E2, isolated from a Korean keratitis patient. The ammonium sulfate-precipitated culture supernatant of the isolate was purified by sequential chromatography on CM-Sepharose, Sephacryl S-200, and mono Q-anion exchange column. The purified 33 kDa protease had a pH optimum of 8.5 and a temperature optimum of 55 degrees C. Phenylmethylsulfonylfluoride and 4-(2- Aminoethyl)-benzenesulfonyl-fluoride, both serine protease specific inhibitors, inhibited almost completely the activity of the 33 kDa protease whereas other classes of inhibitors did not affect its activity. The 33 kDa enzyme degraded various extracellular matrix proteins and serum proteins. Our results strongly suggest that the 33 kDa serine protease secreted from this keratopathogenic Acanthamoeba play important roles in the pathogenesis of amoebic keratitis, such as in corneal tissue invasion, immune evasion and nutrient uptake.


Subject(s)
Acanthamoeba Keratitis/parasitology , Acanthamoeba/enzymology , Serine Endopeptidases/isolation & purification , Serine Endopeptidases/metabolism , Acanthamoeba/isolation & purification , Acanthamoeba/pathogenicity , Animals , Cornea/parasitology , Humans , Hydrogen-Ion Concentration , Korea , Serine Endopeptidases/chemistry , Substrate Specificity , Temperature , Virulence Factors
7.
Exp Mol Med ; 34(1): 53-9, 2002 Mar 31.
Article in English | MEDLINE | ID: mdl-11989979

ABSTRACT

Pulsed electromagnetic field (PEMF) has been shown to improve the rate of peripheral nerve regeneration. In the present study we investigated the expression of neuronal nitric oxide synthase (nNOS) and phospholipase C-gamma1 (PLC-gamma1) in regenerating rat laryngeal nerves during the exposure to PEMF after surgical transection and reanastomosis. Axons were found to regenerate into the distal stump nearly twice faster in PEMF-exposed animals than in the control. Consistently, motor function was better recovered in PEMF-treated rats. The expression of nNOS and PLC-gamma1 was highly enhanced in the regenerated nerves.


Subject(s)
Electromagnetic Fields , Isoenzymes/metabolism , Neurons/physiology , Nitric Oxide Synthase/metabolism , Recurrent Laryngeal Nerve/radiation effects , Type C Phospholipases/metabolism , Animals , Male , Nerve Regeneration/physiology , Nerve Regeneration/radiation effects , Neurons/radiation effects , Nitric Oxide Synthase Type I , Phospholipase C gamma , Rats , Rats, Sprague-Dawley , Recurrent Laryngeal Nerve/cytology , Recurrent Laryngeal Nerve/metabolism , Recurrent Laryngeal Nerve/surgery
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