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1.
J Biotechnol ; 392: 180-189, 2024 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-39038661

RESUMEN

Sialylation during N-glycosylation plays an important role in the half-life of therapeutic glycoproteins in vivo and has sparked interest in the production of therapeutic proteins using recombinant Chinese hamster ovary (rCHO) cells. To improve the sialylation of therapeutic proteins, we examined the effect of sialyllactose supplementation on sialylation of Fc-fusion glycoproteins produced in rCHO cells. Two enzymatically-synthesized sialyllactoses, 3'-sialyllactose (3'-SL) and 6'-sialyllactose (6'-SL), were administered separately to two rCHO cell lines producing the same Fc-fusion glycoprotein derived from DUKX-B11 and DG44, respectively. Two sialyllactoses successfully increased sialylation of Fc-fusion glycoprotein in both cell lines, as evidenced by isoform distribution, sialylated N-glycan formation, and sialic acid content. Increased sialylation by adding sialyllactose was likely the result of increased amount of intracellular CMP-sialic acid (CMP-SA), the direct nucleotide sugar for sialylation. Furthermore, the degree of sialylation enhanced by sialyllactoses was slightly effective or nearly similar compared with the addition of N-acetylmannosamine (ManNAc), a representative nucleotide sugar precursor, to increase sialylation of glycoproteins. The effectiveness of sialyllactose was also confirmed using three commercially available CHO cell culture media. Taken together, these results suggest that enzymatically-synthesized sialyllactose represents a promising candidate for culture media supplementation to increase sialylation of glycoproteins in rCHO cell culture.


Asunto(s)
Cricetulus , Fragmentos Fc de Inmunoglobulinas , Lactosa , Animales , Células CHO , Lactosa/análogos & derivados , Lactosa/metabolismo , Fragmentos Fc de Inmunoglobulinas/genética , Fragmentos Fc de Inmunoglobulinas/metabolismo , Cricetinae , Glicosilación , Proteínas Recombinantes de Fusión/metabolismo , Proteínas Recombinantes de Fusión/genética , Glicoproteínas/metabolismo , Glicoproteínas/genética , Medios de Cultivo/química , Ácidos Siálicos/metabolismo , Ácido N-Acetilneuramínico/metabolismo , Oligosacáridos
2.
Adv Sci (Weinh) ; 11(35): e2403674, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38995107

RESUMEN

Nickel boride catalysts show great potential as low-cost and efficient alternatives to noble-metal catalysts in acidic media; however, synthesizing and isolating a specific phase and composition of nickel boride is nontrivial, and issues persist in their long-term stability as electrocatalysts. Here, a single-crystal nickel boride, Ni23B6, is reported which exhibits high electrocatalytic activity for the hydrogen evolution reaction (HER) in an acidic solution, and that its poor long-term stability can be overcome via encapsulation by single-crystal trilayer hexagonal boron nitride (hBN) film. Interestingly, hBN-covered Ni23B6 on a Ni substrate shows an identical overpotential of 52 mV at a current density of 10 mA cm-2 to that of bare Ni23B6. This phenomenon indicates that the single-crystalline hBN layer is catalytically transparent and does not obstruct HER activation. The hBN/Ni23B6/Ni has remarkable long-term stability with negligible changes to its polarization curves for 2000 cycles, whereas the Ni23B6/Ni shows significant degradation after 650 cycles. Furthermore, chronoamperometric measurements indicate that stability is preserved for >20 h. Long-term stability tests also reveal that the surface morphology and chemical structure of the hBN/Ni23B6/Ni electrode remain preserved. This work provides a model for the practical design of robust and durable electrochemical catalysts through the use of hBN encapsulation.

3.
Int J Med Sci ; 21(6): 1072-1078, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38774745

RESUMEN

Background: This study aimed to evaluate the clinical characteristics, patient's management approaches, and outcomes of the COVID-19 patients in Phu Tho Province, Vietnam. Methods: A retrospective, multicenter study of 2166 COVID-19 patients in 13 hospitals in Phutho Province, Vietnam. The subjects were divided into 3 groups based on vaccination status: unvaccinated group, 1st dose of vaccine group, 2nd dose of vaccine group. The clinical characteristics, management approaches, and outcomes were collected and compared between the 3 groups. Results: The hospitalization rate of the 3 groups decreased from the unvaccinated group, the 1st dose of vaccinated group, to the 2nd dose of vaccinated group, 42.61%; 30,24% and 27,15% respectively. The 19-40 years old group had the highest hospitalization rate (38,1%) together with the group that had not accepted the full COVID 19 vaccination dose (57,64%). The 2nd dose of vaccinated group had the lowest percentages of high temperature, cough, dyspnea, chest pain and sore throat. The unvaccinated group had the highest heart rate, respiratory rate and SpO2 compared to the two other groups. The percentage needing Immunomodulation and Anticoagulant Therapy was highest (6.8% and 1.4 % respectively) in the unvaccinated group. The percentage receiving Antiviral Therapy was highest (42,5%) in those who had received the 2nd dose of vaccine. Conclusions: COVID-19 vaccination improved the symptoms of the patients and should be accepted in all ages.


Asunto(s)
COVID-19 , Hospitalización , SARS-CoV-2 , Humanos , Vietnam/epidemiología , COVID-19/epidemiología , Masculino , Adulto , Femenino , Estudios Retrospectivos , Persona de Mediana Edad , Hospitalización/estadística & datos numéricos , Adulto Joven , Vacunas contra la COVID-19/administración & dosificación , Anciano , Adolescente , Vacunación/estadística & datos numéricos , Servicio de Urgencia en Hospital/estadística & datos numéricos
4.
Heliyon ; 10(8): e29528, 2024 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-38655289

RESUMEN

This study delves into the heavy metal tolerance and accumulation capabilities of Brassica chinensis var. parachinensis (B. chinensis) and Brassica rapa L. (B. rapa) in a pot experiment, specifically focusing on cadmium (Cd), chromium (Cr) and lead (Pb). Agricultural topsoils were spiked with varying concentrations of these heavy metals (0 mg/kg, 75 mg/kg, 150 mg/kg, 225 mg/kg and 300 mg/kg) for each element. The experiment involved cultivating 15 pots each of B. chinensis and B. rapa over 60 days. Results indicated that both Brassica species experienced delayed germination, with B. chinensis exhibiting a significant drop in germination percentage to 53 % at the highest concentration (300 mg/kg), while B. rapa showed a tendency for an increased germination percentage of up to 80 % at elevated metal concentrations; however, these differences were not statistically significant. Both B. chinensis and B. rapa demonstrated a stable decline in growth rate from 0.05 cm/day to 0.04 cm/day with increasing heavy metal concentrations, and the he reduction in relative growth rate was significant at the highest concentration compared to the control. The stress tolerance index revealed a significant decrease in plant heights for B. chinensis, in contrast to the stable performance of B. rapa, showcasing the tolerance of B. rapa to toxic conditions. Despite insignificant differences in fresh biomass due to metal treatments, B. chinensis consistently yielded higher biomass, yet it had a lower edible index due to its higher root biomass. Leaf areas increased significantly in both species at higher soil treatments, while root lengths remained unchanged, suggesting their resilience to elevated heavy metal concentrations. Analysis of plant tissues (leaves, stems and roots) using ICP-OES revealed that B. rapa accumulated the highest Cd concentration (864 mg/kg), whereas B. chinensis accumulated the highest Pb concentration (953 mg/kg) in root parts. Both species significantly accumulated Cr in roots, demonstrating a sequestration mechanism. These findings suggest that both species, particularly, B. rapa possess strong tolerance and accumulation capabilities for non-essential heavy metals, making them potential hyperaccumulators for green remediation techniques in toxic soil environments. Understanding the molecular mechanisms driving these responses and validating phytoremediation potential in real-world scenarios is essential for developing sustainable soil management practices.

5.
Appl Microbiol Biotechnol ; 108(1): 224, 2024 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-38376550

RESUMEN

The occurrence of autophagy in recombinant Chinese hamster ovary (rCHO) cell culture has attracted attention due to its effects on therapeutic protein production. Given the significance of glycosylation in therapeutic proteins, this study examined the effects of autophagy-inhibiting chemicals on sialylation of Fc-fusion glycoproteins in rCHO cells. Three chemical autophagy inhibitors known to inhibit different stages were separately treated with two rCHO cell lines that produce the same Fc-fusion glycoprotein derived from DUKX-B11 and DG44. All autophagy inhibitors significantly decreased the sialylation of Fc-fusion glycoprotein in both cell lines. The decrease in sialylation of Fc-fusion glycoprotein is unlikely to be attributed to the release of intracellular enzymes, given the high cell viability and low activity of extracellular sialidases. Interestingly, the five intracellular nucleotide sugars remained abundant in cells treated with autophagy inhibitors. In the mRNA expression profiles of 27 N-glycosylation-related genes using the NanoString nCounter system, no significant differences in gene expression were noted. With the positive effect of supplementing nucleotide sugar precursors on sialylation, attempts were made to enhance the levels of intracellular nucleotide sugars by supplying these precursors. The addition of nucleotide sugar precursors to cultures treated with inhibitors successfully enhanced the sialylation of Fc-fusion glycoproteins compared to the control culture. This was particularly evident under mild stress conditions and not under relatively severe stress conditions, which were characterized by a high decrease in sialylation. These results suggest that inhibiting autophagy in rCHO cell culture decreases sialylation of Fc-fusion glycoprotein by constraining the availability of intracellular nucleotide sugars. KEY POINTS: •  The autophagy inhibition in rCHO cell culture leads to a significant reduction in the sialylation of Fc-fusion glycoprotein. •  The pool of five intracellular nucleotide sugars remained highly abundant in cells treated with autophagy inhibitors. •  Supplementation of nucleotide sugar precursors effectively restores decreased sialylation, particularly under mild stress conditions but not in relatively severe stress conditions.


Asunto(s)
Autofagia , Glicoproteínas , Animales , Cricetinae , Células CHO , Cricetulus , Glicoproteínas/genética , Nucleótidos , Azúcares
6.
J Chromatogr A ; 1715: 464621, 2024 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-38198876

RESUMEN

White tea contains the highest flavonoids compared to other teas. While there have been numerous studies on the components of different tea varieties, research explicitly focusing on the flavonoid content of white tea remains scarce, making the need for a good flavonoid purification process for white tea even more important. This study compared the adsorption and desorption performance of five types of macroporous resins: D101, HP20, HPD500, DM301, and AB-8. Among the tested resins, AB-8 was selected based on its best adsorption and desorption performance to investigate the static adsorption kinetics and dynamic adsorption-desorption purification of white tea flavonoids. The optimal purification process was determined: adsorption temperature 25 °C, crude tea flavonoid extract pH 3, ethanol concentration 80 %, sample loading flow rate and eluent flow rate 1.5 BV/min, and eluent dosage 40 BV. The results indicated that the adsorption process followed pseudo-second-order kinetics. Under the above purification conditions, the purity of the total flavonoids in the purified white tea flavonoid increased from approximately 17.69 to 46.23 %, achieving a 2.61-fold improvement, indicating good purification results. The purified white tea flavonoid can be further used for nutraceutical and pharmaceutical applications.


Asunto(s)
Flavonoides , Resinas Sintéticas , Flavonoides/análisis , Adsorción , Resinas Sintéticas/química , Extractos Vegetales/química , Resinas de Plantas ,
7.
J Sci Food Agric ; 104(7): 3926-3935, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38252625

RESUMEN

BACKGROUND: Chinese mugwort (Artemisia argyi) possesses extensive pharmacological activities associated with anti-tumour, antioxidative and anti-inflammatory effects. The present study aimed to investigate the antioxidant and anti-ageing effects of A. argyi extract (AAE) on the fruit fly (Drosophila melanogaster) ageing model by detecting antioxidant enzyme activities and the mRNA level of antioxidant genes. RESULTS: AAE could significantly lengthen the mean lifespan, 50% survival days, and maximum lifespan of D. melanogaster, especially when the amount of AAE added reached 6.68 mg mL-1, the mean lifespan of both female and male flies increased by 23.74% and 22.30%, respectively, indicating the effective life extension effect of AAE. At the same time, AAE could improve the climbing ability and tolerance to hydrogen peroxide in D. melanogaster. In addition, the addition of AAE effectively increased the activities of copper-zinc-containing superoxide dismutase, manganese-containing superoxide dismutase and catalase in D. melanogaster and reduced the contents of malondialdehyde. Moreover, when reared with diets containing AAE, the expression of antioxidant-related genes SOD1, SOD2 and CAT was up-regulated in D. melanogaster and down-regulated for MTH genes. CONCLUSION: The study indicates that AAE effectively enhances the antioxidant capacity of D. melanogaster and has potential applications as an antioxidant and anti-ageing agent in the nutraceutical industry. © 2024 Society of Chemical Industry.


Asunto(s)
Artemisia , Drosophila melanogaster , Masculino , Femenino , Animales , Drosophila melanogaster/genética , Antioxidantes/farmacología , Longevidad , Envejecimiento , Suplementos Dietéticos
8.
ACS Nano ; 17(24): 25731-25738, 2023 Dec 26.
Artículo en Inglés | MEDLINE | ID: mdl-38060370

RESUMEN

Transition metal dichalcogenides (TMDs) occur in the thermodynamically stable trigonal prismatic (2H) phase or the metastable octahedral (1T) phase. Phase engineering of TMDs has proven to be a powerful tool for applications in energy storage devices as well as in electrocatalysis. However, the mechanism of the phase transition in TMDs and the synthesis of phase-controlled TMDs remain challenging. Here we report the synthesis of Re-doped WS2 monolayer quantum dots (MQDs) using a simple colloidal chemical process. We find that the incorporation of a small amount of electron-rich Re atoms in WS2 changes the metal-metal distance in the 2H phase initially, which introduces strain in the structure (strained 2H (S2H) phase). Increasing the concentration of Re atoms sequentially transforms the S2H phase into the 1T and 1T' phases to release the strain. In addition, we performed controlled experiments by doping MoS2 with Re to distinguish between Re and Mo atoms in scanning transmission electron microscopy images and quantified the concentration range of Re atoms in each phase of MoS2, indicating that phase engineering of WS2 or MoS2 is possible by doping with different amounts of Re atoms. We demonstrate that the 1T' WS2 MQDs with 49 at. % Re show superior catalytic performance (a low Tafel slope of 44 mV/dec, a low overpotential of 158 mV at a current density of 10 mA/cm2, and long-term durability up to 5000 cycles) for the hydrogen evolution reaction. Our findings provide understanding and control of the phase transitions in TMDs, which will allow for the efficient manufacturing and translation of phase-engineered TMDs.

9.
ACS Nano ; 17(23): 23936-23943, 2023 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-37991883

RESUMEN

The electrochemical production of H2O2 via the two-electron oxygen-reduction reaction (2e- ORR) has been actively studied using systems with atomically dispersed metal-nitrogen-carbon (M-N-C) structures. However, the development of well-defined M-N-C structures that restrict the migration and agglomeration of single-metal sites remains elusive. Herein, we demonstrate a Langmuir-Blodgett (LB) monolayer of cobalt phthalocyanine (CoPc) on monolayer graphene (LB CoPc/G) as a single-metal catalyst for the 2e- ORR. The as-prepared CoPc LB monolayer has a ß-form crystalline structure with a lattice space for the facile adsorption of oxygen molecules on the cobalt active sites. The CoPc LB monolayer system provides highly exposed Co atoms in a well-defined structure without agglomeration, resulting in significantly improved catalytic activity, which is manifested by a very high H2O2 production rate per catalyst (31.04 mol gcat-1 h-1) and TOF (36.5 s-1) with constant production stability for 24 hours. To the best of our knowledge, the CoPc LB monolayer system exhibits the highest H2O2 production rate per active site. This fundamental study suggests that an LB monolayer of molecules with single-metal atoms as a well-defined structure works for single-atom catalysts.

10.
J Biotechnol ; 375: 12-16, 2023 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-37634828

RESUMEN

Increasing the screening efficiency and maintaining the N-terminal cleavage pattern are key factors in the development of an in vitro synthetic signal peptide screening system for high therapeutic protein production in Chinese hamster ovary (CHO) cells. This study improved the in vitro screening system of synthetic signal peptides in CHO cells for therapeutic protein production by modifying the expression vector. Incorporating a leaky stop codon with IgG transmembrane and cytoplasmic domains into the expression vector improved the proportion of high producers in establishing stable CHO cell pools. The selected signal peptides from stable CHO cell pools that were generated using degenerate codon-based oligonucleotides with a conserved polar carboxy-terminal domain in the native signal peptide showed similar N-terminal cleavage patterns to the native one. In addition, replacing native signal peptide with selected synthetic signal peptides did not influence the sialylated N-linked glycan formation and biological activity of therapeutic Fc-fusion glycoprotein in CHO cells. Thus, an in vitro synthetic signal peptide screening system can be used for therapeutic Fc-fusion glycoprotein production in CHO cells with an enhanced specific protein productivity while maintaining the N-terminal cleavage pattern similar to the native one.


Asunto(s)
Oligonucleótidos , Señales de Clasificación de Proteína , Animales , Cricetinae , Señales de Clasificación de Proteína/genética , Células CHO , Cricetulus
11.
BMC Pregnancy Childbirth ; 23(1): 298, 2023 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-37118693

RESUMEN

BACKGROUND: This paper reports on results of a health system strengthening implementation research initiative conducted the Upper East Region of northern Ghana. Transformative interventions to accelerate and strengthen the health delivery were implemented that included empowering community leaders and members to actively participate in health delivery, strengthening the referral systems through the provision of community transport systems, providing basic medical equipment to community clinics, and improving the skills of critical health staff through training. METHODS: A mixed method design was used to evaluate the impact of the interventions. A quantitative evaluation employed a flexible research design to test the effects of various component activities of the project. To assess impact, a pre-versus-post randomized cluster survey design was used. Qualitative research was conducted with focus group data and individual in depth interviews to gauge the views of various stakeholders associated with the implementation process. RESULTS: After intervention, significant improvements in key maternal and child health indicators such as antenatal and postnatal care coverage were observed and increases in the proportion of deliveries occurring in health facilities and assisted by skilled health personnel relative to pre-intervention conditions. There was also increased uptake of oral rehydration salts (ORS) for treatment of childhood diarrhoea, as well as marked reductions in the incidence of upper respiratory infections (URI). CONCLUSIONS: A pre-and post-evaluation of impact suggests that the programme had a strong positive impact on the functioning of primary health care. Findings are consistent with the proposition that the coverage and content of the Ghana Community-based Health Planning and Services programme was improved by program interventions and induced discernable changes in key indicators of health system performance.


Asunto(s)
Salud Infantil , Salud Pública , Niño , Humanos , Femenino , Embarazo , Ghana , Planificación en Salud Comunitaria , Instituciones de Atención Ambulatoria , Servicios de Salud Comunitaria
12.
Heliyon ; 9(2): e13547, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36816267

RESUMEN

A field study was established to determine the phytoextraction potential of six vegetable species, namely Amaranthus viridis L., Basella alba L., Brassica chinensis var. Parachinensis, Brassica rapa L., Capsicum frutescens L., and Ocimum tenuiflorum L.. These edible plants were selected for their short growth cycles and high biomass production, which are some traits for efficient phytoremediation. Following acid digestion of the soil and vegetable samples using the USEPA 3050B acid digestion method, the extracts were analyzed for Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn using ICP-OES. Results in soil samples showed that the concentrations of both beneficial and essential heavy metals, and non-essential heavy metals are below the WHO, USEPA, and CCME soil quality guidelines. Al is one of the highest concentrations found in the soil samples but it tends to accumulate in the root part of all vegetable species compared to the aboveground parts. In general, B. rapa L. accumulated the highest level of Cd (0.4 mg/kg) and Pb (5.71 mg/kg), while B. alba L. accumulated the highest Cr (2.62 mg/kg) in all plant parts. The findings in this study indicated that Co, Cu, Fe, Mn and Zn were mostly accumulated in leaves of A. viridis L. (Co, Cu, Fe, Mn and Zn), B. alba L. (Co, Fe and Mn), B. chinensis (Mn and Zn) and O. tenuiflorum L. (Mn), and roots of C. frutescens L. (Co, Cu, Fe and Mn), B. alba L. (Co, Cu and Zn), A. viridis L. and B. chinensis (Cu and Fe) and B. rapa L. (Fe). Cr, Pb and Ni were significantly greater in B. alba L. (Cr) And B. rapa L. (Ni and Pb) roots. MTF >1 was observed in the roots of all species for Co, Cd, Zn, and Ni. BTC values varied between the different vegetable species with A. viridis L. having the greatest heavy metal mobility between its plant parts and the best heavy metal phytoextraction potential among other species. The PCA biplots showed that heavy metals were partitioned differently between various plant parts of the vegetable species and can be explained by the first two components (PC1 and PC2) which were associated with the root and/or leaf parts for most vegetable species.

13.
Ther Adv Respir Dis ; 17: 17534666231155772, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36846942

RESUMEN

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a known risk factor for venous thromboembolism (VTE). However, it is currently unknown which factors are associated with an increase of VTE in patients with IPF. OBJECTIVES: We estimated the incidence of VTE in patients with IPF and identified clinical characteristics related to VTE in patients with IPF. DESIGN AND METHODS: De-identified nationwide health claim data from 2011 to 2019 was collected from the Korean Health Insurance Review and Assessment database. Patients with IPF were selected if they had made at least one claim per year under the J84.1 [International Classification of Diseases and Related Health Problems, 10th Revision (ICD-10)] and V236 codes of rare intractable diseases. We defined the presence of VTE as at least one claim of pulmonary embolism and deep vein thrombosis ICD-10 codes. RESULTS: The incidence rate per 1000 person-years of VTE was 7.08 (6.44-7.77). Peak incidence rates were noted in the 50-59 years old male and 70-79 years old female groups. Ischemic heart disease, ischemic stroke, and malignancy were associated with VTE in patients with IPF, with an adjusted hazard ratio (aHR) of 1.25 (1.01-1.55), 1.36 (1.04-1.79), and 1.53 (1.17-2.01). The risk for VTE was increased in patients diagnosed with malignancy after IPF diagnosis (aHR = 3.18, 2.47-4.11), especially lung cancer [hazard ratio (HR) = 3.78, 2.90-4.96]. Accompanied VTE was related to more utilization of medical resources. CONCLUSION: Ischemic heart disease, ischemic stroke, and malignancy, especially lung cancer, were related to higher HR for VTE in IPF.


Asunto(s)
Fibrosis Pulmonar Idiopática , Neoplasias Pulmonares , Accidente Cerebrovascular , Tromboembolia Venosa , Humanos , Masculino , Femenino , Persona de Mediana Edad , Tromboembolia Venosa/diagnóstico , Tromboembolia Venosa/epidemiología , Factores de Riesgo , Fibrosis Pulmonar Idiopática/epidemiología , Fibrosis Pulmonar Idiopática/complicaciones , Neoplasias Pulmonares/complicaciones , Accidente Cerebrovascular/complicaciones
14.
Tour Manag Perspect ; 44: 101033, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36250133

RESUMEN

This study examines the impact of extended tourist trust constructs on domestic travel experiences, subjective well-being, and future travel intention in the pandemic. Data was obtained through a survey conducted on 1181 Korean and American domestic tourists. The results show that policy trust and destination trust have positive effects on travel frequency and satisfaction. Moreover, interactional trust positively impacted travel satisfaction. While both travel frequency and travel satisfaction have positive impacts on subjective well-being of travelers, travel satisfaction has a stronger impact on subjective well-being than travel frequency. However, certain relationships were influenced by national backgrounds (U·S vs. Korea).

15.
ACS Nano ; 16(7): 11059-11065, 2022 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-35776412

RESUMEN

The metallic property of metastable 1T' WSe2 and its promising catalytic performance have attracted considerable interest. A hot injection method has been used to synthesize 1T' WSe2 with a three-dimensional morphology; however, this method requires two or more precursors and long-chain ligands, which inhibit the catalytic performance. Here, we demonstrate the synthesis of 1T' WSe2 on a substrate by a simple heating-up method using a single precursor, tetraethylammonium tetraselenotungstate [(Et4N)2WSe4]. The triethylamine produced after the reaction is an electron donor that yields negatively charged WSe2, which is stabilized by triethylammonium cations as intercalants between layers and induces 1T' WSe2. The purity of 1T' WSe2 is higher on oxygen-containing crystalline substrates than amorphous substrates because the strong adhesion between WSe2 and the substrate can produce sufficient triethylammonium (TEA) intercalation. Among the oxygen-containing crystal substrates, the substrate with a lower lattice mismatch with 1T' WSe2 showed higher 1T' purity due to the uniform TEA intercalation. Furthermore, 1T' WSe2 on carbon cloth exhibited a more enhanced catalytic performance in the hydrogen evolution reaction (197 mV at 10 mA/cm2) than has been reported previously.

16.
Appl Microbiol Biotechnol ; 106(9-10): 3571-3582, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35581431

RESUMEN

Optimizing appropriate signal peptides in mammalian cell-based protein production is crucial given that most recombinant proteins produced in mammalian cells are thought to be secreted proteins. Until now, most studies on signal peptide in mammalian cells have replaced native signal peptides with well-known heterologous signal peptides and bioinformatics-based signal peptides. In the present study, we successfully established an in vitro screening system for synthetic signal peptide in CHO cells by combining a degenerate codon-based oligonucleotides library, a site-specific integration system, and a FACS-based antibody detection assay. Three new signal peptides were screened using this new screening system, confirming to have structural properties as signal peptides by the SignalP web server, a neural network-based algorithm that quantifies the signal peptide-ness of amino acid sequences. The novel signal peptides selected in this study increased Fc-fusion protein production in CHO cells by increasing specific protein productivity, whereas they did not negatively affect cell growth. Particularly, the SP-#149 clone showed the highest qp, 0.73 ± 0.01 pg/cell/day from day 1 to day 4, representing a 1.47-fold increase over the native signal peptide in a serum-free suspension culture mode. In addition, replacing native signal peptide with the novel signal peptides did not significantly affect sialylated N-glycan formation, N-terminal cleavage pattern, and biological function of Fc-fusion protein produced in CHO cells. The overall results indicate the utility of a novel in vitro screening system for synthetic signal peptide for mammalian cell-based protein production. KEY POINTS: • An in vitro screening system for synthetic signal peptide in mammalian cells was established • This system combined a degenerate codon-based library, site-specific integration, and a FACS-based detection assay • The novel signal peptides selected in this study could increase Fc-fusion protein production in mammalian cells.


Asunto(s)
Péptidos , Señales de Clasificación de Proteína , Animales , Células CHO , Cricetinae , Cricetulus , Péptidos/química , Péptidos/genética , Señales de Clasificación de Proteína/genética , Proteínas Recombinantes de Fusión/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
17.
Innate Immun ; 28(3-4): 122-129, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35612375

RESUMEN

Monocytes and macrophages that originate from common myeloid progenitors perform various crucial roles in the innate immune system. Stimulation with LPS combined with TLR4 drives the production of pro-inflammatory cytokines through MAPKs and NF-κB pathway in different cells. However, the difference in LPS susceptibility between monocytes and macrophages is poorly understood. In this study, we found that pro-inflammatory cytokines-IL-1ß, IL-6 and TNFα showed greater induction in phorbol-12-myristate-13-acetate (PMA)-differentiated THP-1 cells than in THP-1 cells. To determine the difference in cytokine expression, the surface proteins such as TLR4-related proteins and intracellular adaptor proteins were more preserved in PMA-differentiated THP-1 cells than in THP-1 cells. MyD88 is a key molecule responsible for the difference in LPS susceptibility. Moreover, MAPKs and NF-κB pathway-related molecules showed higher levels of phosphorylation in PMA-differentiated THP-1 cells than in THP-1 cells. Upon MyD88 depletion, there was no difference in the phosphorylation of MAPK pathway-related molecules. Therefore, these results demonstrate that the difference in LPS susceptibility between THP-1 cells and PMA-differentiated THP-1 cells occur as a result of gap between the activated MAPKs and NF-κB pathways via changes in the expression of LPS-related receptors and MyD88.


Asunto(s)
Lipopolisacáridos , Células THP-1 , Receptor Toll-Like 4 , Citocinas/metabolismo , Humanos , Receptores de Lipopolisacáridos/metabolismo , Lipopolisacáridos/farmacología , Monocitos/efectos de los fármacos , Monocitos/metabolismo , Factor 88 de Diferenciación Mieloide/metabolismo , FN-kappa B/metabolismo , Células THP-1/efectos de los fármacos , Células THP-1/metabolismo , Acetato de Tetradecanoilforbol/farmacología , Receptor Toll-Like 4/metabolismo
18.
Tour Manag ; 88: 104428, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34539019

RESUMEN

The COVID-19 pandemic has forced tourism practitioners to create efficient strategies to attract travelers. Using three theoretical frameworks, such as tourist trust (political, destination, and interactional trust), travel constraint (intrapersonal, interpersonal, and "social distancing" structural constraint), and extended theory of planned behavior (travel attitude, perceived behavioral control, subjective norm, perceived health risk, past travel experience), we develop a comprehensive framework to explain the impact of travel promoting, restricting, and attitudinal factors on travel decision during and after the pandemic. Data was obtained through an extensive survey conducted on 1451 Korean travelers and was analyzed using probabilistic choice models and count models. The results show the specific factors that determine travel decisions during the pandemic (whether to travel and frequency) and travel intention after the pandemic. This study provides important theoretical and practical insights into how to develop successful COVID-19 recovery strategies in the tourism industry.

19.
Heliyon ; 7(9): e07945, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34541353

RESUMEN

Determination of heavy metal concentrations in vegetables and agricultural soils is crucial because high levels of heavy metals could affect soil quality, crop production and safe consumption of crops. A field study was conducted to determine the heavy metal concentrations and their transfer from agricultural soils to different parts (leaf, stem, and root) of Brassica juncea (L.) Czern. In addition, potential health risks of contamination in the vegetables grown in the field were evaluated. Acid digestion method USEPA 3050B in combination with ICP-OES were used to analyze heavy metal (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) contents in both pre- and post-harvest soils and vegetable samples. Results showed that none of the heavy metals in soils had concentrations above the maximum safety limits based on the WHO, USEPA and CCME guidelines. Calculated metal transfer factor (MTF >1) showed B. juncea accumulated Cd, Co, Ni, Pb and Zn in leaves, stems and roots, but Cu and Mn, as well as Cr were only accumulated in stems and roots, respectively. There were variations in heavy metal contents between the different parts of B. juncea, but only Cd and Pb contents were above the maximum allowable limit recommended by FAO/WHO. PCA analysis was able to identify 4 major components corresponding to 38.38%, 28.98%, 14.39% and 10.67% of the total variance and PC1 was clearly associated to leaves of B. juncea. Based on the MTF values, only Cd was found to have a value of HRI >1 compared to the other heavy metals, implying potential health risk associated with long-term ingestion of the vegetable.

20.
Sensors (Basel) ; 21(12)2021 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-34204684

RESUMEN

This paper presents a remote 16 Ch × 200 GHz dense wavelength division multiplexing (DWDM)-passive optical fiber sensor (OFS) network. We particularly investigate the remote water-level monitoring capability of the OFS network based on an optical power measurement that features simplicity and a fast processing speed. The OFS network utilizes a seeded amplified spontaneous emission (ASE) light that is spectrum-sliced and distributed by an arrayed waveguide grating (AWG) towards multiple sensing units (SU), where each SU is installed at a different height in the water pool. Then, each SU reflects either of the two different optical powers according to the medium (air vs. water) back to the monitoring station. Therefore, the total received optical power at the monitoring station linearly changes according to the water level. We can simply recognize the water level by utilizing the optical power meter (OPM) at the monitoring station rather than the optical spectrum analyzer (OSA), which is bulky and expensive and requires a relatively long processing time. Consequently, we can reduce the system complexity, processing time, and cost (both installation and maintenance). However, the OPM-based OFS network requires a new methodology to derive the water level from the measured optical power. Thus, we come up with the reference-to-power ratio (RPR) analysis, which can be used for the maximum distance analysis as well as water level recognition. Based on the new reception architecture supported by the new post-processing scheme, the OFS network can distinguish 17 different water levels of the SFP at the monitoring station, which is >40 km away from the SFP, without using any active devices (such as optical amplifiers) at the remote places.


Asunto(s)
Plantas de Energía Nuclear , Fibras Ópticas , Amplificadores Electrónicos , Agua
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