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1.
Food Sci Biotechnol ; 33(7): 1633-1640, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38623427

RESUMO

The efficacy of an in-package microbial inactivation method, combining H2O2 and atmospheric dielectric barrier discharge cold plasma (ADCP) treatments (H2O2-ADCP), in reducing contamination of Brassica oleracea (cabbage) slices was investigated. Cabbage slices were placed in a polyethylene terephthalate container with a H2O2-soaked polypropylene pad attached to the inside of the lid, followed by subjecting the closed container to ADCP treatment. The H2O2-ADCP treatment inactivated Escherichia coli O157:H7 and Listeria monocytogenes, resulting in reductions of 1.8 and 2.0 log CFU/g, respectively, which were greater than the sum of the inactivation effects observed with each individual treatment. The combined treatment decreased the count of Bacillus cereus spores and indigenous bacteria by 1.0 log spores/g and 1.3 log CFU/g, respectively. Moreover, the in-package method did not alter the moisture content or texture of cabbage slices. These results demonstrate the potential of H2O2-ADCP as a microbial decontamination method for packaged cabbage slices.

2.
Curr Issues Mol Biol ; 46(3): 2251-2262, 2024 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-38534760

RESUMO

Prostate cancer accounts for 14% of male cancer-related fatalities in the UK. Given the challenges associated with hormone-based therapies in the context of androgen-independent prostate cancer, there is an imperative need for research into anticancer drugs. N0821, a peptide belonging to the Trp-Arg dense region and derived from the homologous region of various bee species, shows substantial potential for an anticancer effect. Both MTT assays and 3D spheroid assays were conducted to substantiate its antiproliferation potential and strongly indicated the antiproliferation effect of N0820 (WWWWRWWRKI) and N0821 (YWWWWRWWRKI). Notably, the mechanism underlying this effect is related to the downregulation of CCNA2 and the upregulation of CCNE1. Cell cycle arrest results from the reduction of CCNA2 in the S/G2 phase, leading to the accumulation of CCNE1. Our peptides were predicted to make an α-helix structure. This can act as an ion channel in the cell membrane. Therefore, we analyzed genes implicated in the influx of calcium ions into the mitochondria. Trp-Arg dense-region peptides are known for their antibacterial properties in targeting cell membranes, making the development of resistance less likely. Hence, further research in this area is essential and promising.

3.
Brain Stimul ; 17(2): 405-412, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38537689

RESUMO

Transcranial focused ultrasound (tFUS) neuromodulation emerges as a promising non-invasive approach for improving neurological conditions. Extinction of conditioned fear has served as a prime model for exposure-based therapies for anxiety disorders. We investigated whether tFUS stimulation to a critical brain area, the infralimbic subdivision of the prefrontal cortex (IL), could facilitate fear extinction using rats. In a series of experiments, tFUS was delivered to the IL of a freely-moving rat and compared to sham stimulation (tFUS vs. SHAM). Initially, Fos expression in the IL was measured shortly after the stimulation. The results show that Fos expression was significantly increased in the IL but not in the neighboring regions compared to SHAM. Subsequently, two groups of rats were subjected to fear conditioning, extinction, and retention while receiving stimulation during the extinction. Rats in the tFUS group froze significantly less than SHAM during both extinction and retention tests. Importantly, the reduced freezing in the tFUS group was not attributable to non-specific effect such as auditory noise, as both groups demonstrated a similar level of locomotive activity in an open field regardless of the stimulation condition. Finally, we replicated the procedure with a shortened conditioning-to-extinction interval (15 min) to induce immediate extinction deficit. The tFUS group showed a facilitated reduction in freezing during the extinction, which persisted in the subsequent retention session compared to SHAM. In summary, the current findings suggest that tFUS stimulation in the IL facilitates fear extinction, offering a potential therapeutic regimen for fear-related psychiatric disorders.

4.
Infect Chemother ; 56(1): 83-87, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38527782

RESUMO

We aimed to evaluate the clinical features of respiratory syncytial virus (RSV) infection and risk factors for severe RSV disease among Korean children in 2022/2023. A total of 235 children were identified, and 84.3% were hospitalized. Patients under 3 months and 2 years of age accounted for 20.9% and 54.5%, respectively. Pneumonia was diagnosed in 40.9% of children and bronchiolitis in 23.8%. Respiratory support and intensive care were required in 43.4% and 7.7% of patients, respectively. Haemophilus influenzae nasopharyngeal colonization and the presence of underlying disease showed a significant correlation with severity indicators. The clinical impact of RSV infection was high on infants and toddlers, even those having no underlying disease or not being indicated for palivizumab.

5.
Aging (Albany NY) ; 16(3): 1983-2004, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38301041

RESUMO

GV1001, which mimics the activity of human telomerase reverse transcriptase, protects neural cells from amyloid beta (Aß) toxicity and other stressors through extra-telomeric function, as noted in our prior in vitro studies. As per a recent phase II clinical trial, it improves cognitive function in patients with moderate to severe dementia. However, the underlying protective mechanisms remain unclear. This study aimed to investigate the effects of GV1001 on neurodegeneration, senescence, and survival in triple transgenic Alzheimer's disease (3xTg-AD) mice. GV1001 (1 mg/kg) was subcutaneously injected into old 3xTg-AD mice thrice a week until the endpoint for sacrifice, and survival was analysed. Magnetic resonance imaging (MRI) and Prussian blue staining (PBS) were performed to evaluate entry of GV1001 entrance into the brain. Diverse molecular studies were performed to investigate the effect of GV1001 on neurodegeneration and cellular senescence in AD model mice, with a particular focus on BACE, amyloid beta1-42 (Aß1-42), phosphorylated tau, volume of dentate gyrus, ß-galactosidase positive cells, telomere length, telomerase activity, and ageing-associated proteins. GV1001 crossed the blood-brain barrier, as confirmed by assessing the status of ferrocenecarboxylic acid-conjugated GV1001 using magnetic resonance imaging and PBS. GV1001 increased the survival of 3xTg-AD mice. It decreased BACE and Aß1-42 levels, neurodegeneration (i.e., reduced CA1, CA3 and dentate gyrus volume, decreased levels of senescence-associated ß-galactosidase positive cells, and increased telomere length and telomerase activity), and levels of ageing-associated proteins. We suggest that GV1001 exerts anti-ageing effects in 3xTg-AD mice by reducing neurodegeneration and senescence, which contributes to improved survival.


Assuntos
Doença de Alzheimer , Telomerase , Camundongos , Humanos , Animais , Peptídeos beta-Amiloides/metabolismo , Longevidade , Camundongos Transgênicos , Telomerase/metabolismo , Doença de Alzheimer/metabolismo , Envelhecimento , Modelos Animais de Doenças , beta-Galactosidase/metabolismo , Proteínas tau/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo
6.
Brain Behav Immun ; 115: 295-307, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37884161

RESUMO

GV1001 protects neural cells from amyloid-ß (Aß) toxicity and other stressors in in vitro studies and demonstrates clinically beneficial effects in patients with moderate to severe Alzheimer's disease (AD). Here, we investigated the protective effects and mechanism of action of GV1001 in triple transgenic AD (3xTg-AD) mice. We found that GV1001 improved memory and cognition in middle- and old-aged 3xTg-AD mice. Additionally, it reduced Aß oligomer and phospho-tau (Ser202 and Thr205) levels in the brain, and mitigated neuroinflammation by promoting a neuroprotective microglial and astrocyte phenotype while diminishing the neurotoxic ones. In vitro, GV1001 bound to gonadotropin releasing hormone receptors (GnRHRs) with high affinity. Levels of cyclic adenosine monophosphate, a direct downstream effector of activated GnRHRs, increased after GV1001 treatment. Furthermore, inhibition of GnRHRs blocked GV1001-induced effects. Thus, GV1001 might improve cognitive and memory functions of 3xTg-AD mice by suppressing neuroinflammation and reducing Aß oligomers levels and phospho-tau by activating GnRHRs and their downstream signaling pathways.


Assuntos
Doença de Alzheimer , Humanos , Camundongos , Animais , Pessoa de Meia-Idade , Idoso , Doença de Alzheimer/metabolismo , Camundongos Transgênicos , Receptores LHRH , Doenças Neuroinflamatórias , Proteínas tau/genética , Proteínas tau/metabolismo , Peptídeos beta-Amiloides/metabolismo , Hormônio Liberador de Gonadotropina , Modelos Animais de Doenças
7.
Sci Rep ; 13(1): 21328, 2023 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-38044360

RESUMO

Normal pressure hydrocephalus (NPH) patients had altered white matter tract integrities on diffusion tensor imaging (DTI). Previous studies suggested disproportionately enlarged subarachnoid space hydrocephalus (DESH) as a prognostic sign of NPH. We examined DTI indices in NPH subgroups by DESH severity and clinical symptoms. This retrospective case-control study included 33 NPH patients and 33 age-, sex-, and education-matched controls. The NPH grading scales (0-12) were used to rate neurological symptoms. Patients with NPH were categorized into two subgroups, high-DESH and low-DESH groups, by the average value of the DESH scale. DTI indices, including fractional anisotropy, were compared across 14 regions of interest (ROIs). The high-DESH group had increased axial diffusivity in the lateral side of corona radiata (1.43 ± 0.25 vs. 1.72 ± 0.25, p = 0.04), and showed decreased fractional anisotropy and increased mean, and radial diffusivity in the anterior and lateral sides of corona radiata and the periventricular white matter surrounding the anterior horn of lateral ventricle. In patients with a high NPH grading scale, fractional anisotropy in the white matter surrounding the anterior horn of the lateral ventricle was significantly reduced (0.36 ± 0.08 vs. 0.26 ± 0.06, p = 0.03). These data show that DESH may be a biomarker for DTI-detected microstructural alterations and clinical symptom severity.


Assuntos
Hidrocefalia de Pressão Normal , Hidrocefalia , Substância Branca , Humanos , Hidrocefalia de Pressão Normal/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Substância Branca/diagnóstico por imagem , Estudos de Casos e Controles , Estudos Retrospectivos , Anisotropia , Hidrocefalia/diagnóstico por imagem
8.
ACS Nano ; 17(23): 24404-24416, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-38039189

RESUMO

Inflammatory bowel disease (IBD) is characterized by an inappropriate and persistent inflammatory immune response and is often accompanied by excessive reactive oxygen species (ROS) production. For effective IBD treatment, there is a high demand for safe and targeted therapy that can be orally administered. In this study, we aimed to propose the use of inflamed colon-targeted antioxidant nanotherapeutics (ICANs) for in situ oxidative stress level modulation in colitis. ICANs consist of mesoporous silica nanoparticles (MSNs) with surface-attached ROS-scavenging ceria nanoparticles (CeNPs), which are further coated with poly(acrylic acid) (PAA) to facilitate preferential adherence to inflamed colon tissues through electrostatic interaction. We achieved a high ROS-scavenging property that remained effective even after artificial gastrointestinal fluid incubation by optimization of the molecular weight and PAA-coating pH. The orally administered ICANs demonstrated enhanced adherence to inflamed colon tissues in an acute inflammation mouse model of IBD induced by dextran sulfate sodium. This targeted delivery resulted in gut microenvironment modulation by regulating redox balance and reducing inflammatory cell infiltration, thereby suppressing the colitis-associated immune response. These findings highlight the potential of noninvasive ICANs as a promising candidate for treating inflammatory intestinal diseases by oxidative stress level modulation in colitis.


Assuntos
Colite , Doenças Inflamatórias Intestinais , Camundongos , Animais , Espécies Reativas de Oxigênio/metabolismo , Colite/induzido quimicamente , Colite/tratamento farmacológico , Colite/metabolismo , Colo/metabolismo , Doenças Inflamatórias Intestinais/tratamento farmacológico , Estresse Oxidativo , Oxirredução , Antioxidantes/farmacologia , Modelos Animais de Doenças
9.
Microbiol Immunol ; 67(10): 456-467, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37525428

RESUMO

Defensins and inflammation are innate immune barriers of the body against infectious pathogens. Searching for a compound that can inhibit infectious diseases by affecting human ß-defensin (HBD) and proinflammatory cytokines is the new trend in research to control bacterial infection. The aim of this study is to provide a natural compound, Filipendula glaberrima Nakai extract (FGE), which is able to induce the expression of an antimicrobial defensin as well as reduce inflammation. FGE induced the expression of HBD2 and HBD3 through activating both p38 and NF-κB signaling pathways. Furthermore, FGE inhibited the expression of TNF-α and IL-6 via p38 and NF-κB pathways in Staphylococcus aureus-stimulated THP1 cells. Injection of FGE alleviated cutaneous erythema and swelling caused by S. aureus injection in mice ears. Taken together, FGE could reduce bacterial infection by inducing the expression of defensin and anti-inflammatory activity.


Assuntos
Infecções Bacterianas , Filipendula , beta-Defensinas , Animais , Camundongos , Humanos , NF-kappa B/metabolismo , Células Cultivadas , Staphylococcus aureus , beta-Defensinas/metabolismo , Inflamação/tratamento farmacológico
10.
Biomolecules ; 13(8)2023 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-37627251

RESUMO

Recently, natural silk nonwoven fabrics have attracted attention in biomedical and cosmetic applications because of their excellent biocompatibility, mechanical properties, and easy preparation. Herein, silk nonwoven fabrics were prepared by carding silk filaments to improve their productivity, and the effect of sericin content on the structure and properties of silk nonwoven fabrics was investigated. Owing to the binding effect of sericin in silk, a natural silk nonwoven fabric was successfully prepared through carding, wetting, and hot press treatments. Sericin content affected the structural characteristics and properties of the silk nonwoven fabrics. As the sericin content increased, the silk nonwoven fabrics became more compact with reduced porosity and thickness. Further, with increasing sericin content, the crystallinity and elongation of the silk nonwoven fabrics decreased while the moisture regain and the maximum stress increased. The thermal stability of most silk nonwoven fabrics was not affected by the sericin content. However, silk nonwoven fabrics without sericin had a lower thermal decomposition temperature than other nonwoven fabrics. Regardless of the sericin content, all silk nonwoven fabrics exhibited optimal cell viability and are promising candidates for cosmetic and biomedical applications.


Assuntos
Sericinas , Têxteis , Seda , Sobrevivência Celular , Citoesqueleto
13.
Free Radic Biol Med ; 204: 385-393, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37245530

RESUMO

Cerebral microvasculature of patients with Alzheimer's disease (AD) exhibits reduced capillary diameter and impaired blood flow. Molecular mechanisms of ischemic vessels affecting AD progressions have not been well established yet. In the present study, we found that in vivo triple (PS1M146V, APPswe, tauP301L) transgenic AD mouse model (3x-Tg AD) brains and retinas showed hypoxic vessels expressing hypoxyprobe and hypoxia inducible factor-1α (HIF-1α). To mimic in vivo hypoxic vessels, we used in vitro oxygen-glucose deprivation (OGD)-treated endothelial cells. HIF-1α protein was increased through reactive oxygen species (ROS) producing NADPH oxidases (NOX) (i.e., Nox2, Nox4). OGD-induced HIF-1α upregulated Nox2 and Nox4, demonstrating crosstalk between HIF-1α and NOX (i.e., Nox2, Nox4). Interestingly, NLR family pyrin domain containing 1 (NLRP1) protein was promoted by OGD, and such effect was blocked by downregulation of Nox4 and HIF-1α. Knockdown of NLRP1 also diminished OGD-mediated protein levels of Nox2, Nox4, and HIF-1α in human brain microvascular endothelial cells. These results showed interplay among HIF-1α, Nox4 and NLRP1 in OGD-treated endothelial cells. Expression of NLRP3 was not detected well in hypoxic endothelial cells of 3x-Tg AD retinas or OGD-treated endothelial cells. Instead, hypoxic endothelial cells of 3x-Tg AD brains and retinas markedly expressed NLRP1, the adaptor molecule apoptosis-associated speck-like protein containing a CARD (ASC), caspase-1, and interleukin-1ß (IL-1ß). Taken together, our results suggest that AD brains and retinas can trigger chronic hypoxia especially in microvascular endothelial cells, consequently leading to NLRP1 inflammasome formation and upregulation of ASC-caspase-1-IL-1ß cascades. In addition, NLRP1 can stimulate HIF-1α expression and form HIF-1α-NLRP1 circuit. These consequences might further destroy vascular system in AD.


Assuntos
Doença de Alzheimer , Células Endoteliais , Animais , Humanos , Camundongos , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Caspase 1/metabolismo , Células Endoteliais/metabolismo , Hipóxia/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Camundongos Transgênicos , NADPH Oxidases/metabolismo , Proteínas NLR/metabolismo , Oxigênio/metabolismo , Circulação Cerebrovascular/fisiologia
15.
J Enzyme Inhib Med Chem ; 38(1): 2191164, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36950944

RESUMO

Prions are infectious protein particles known to cause prion diseases. The biochemical entity of the pathogen is the misfolded prion protein (PrPSc) that forms insoluble amyloids to impair brain function. PrPSc interacts with the non-pathogenic, cellular prion protein (PrPC) and facilitates conversion into a nascent misfolded isoform. Several small molecules have been reported to inhibit the aggregation of PrPSc but no pharmacological intervention was well established thus far. We, here, report that acylthiosemicarbazides inhibit the prion aggregation. Compounds 7x and 7y showed almost perfect inhibition (EC50 = 5 µM) in prion aggregation formation assay. The activity was further confirmed by atomic force microscopy, semi-denaturing detergent agarose gel electrophoresis and real-time quaking induced conversion assay (EC50 = 0.9 and 2.8 µM, respectively). These compounds also disaggregated pre-existing aggregates in vitro and one of them decreased the level of PrPSc in cultured cells with permanent prion infection, suggesting their potential as a treatment platform. In conclusion, hydroxy-2-naphthoylthiosemicarbazides can be an excellent scaffold for the discovery of anti-prion therapeutics.


Assuntos
Doenças Priônicas , Príons , Humanos , Príons/metabolismo , Proteínas Priônicas/metabolismo , Encéfalo , Doenças Priônicas/tratamento farmacológico , Doenças Priônicas/metabolismo , Doenças Priônicas/patologia , Células Cultivadas
16.
Molecules ; 28(6)2023 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-36985716

RESUMO

Both defensin and inflammation are part of the human innate immune system that responds rapidly to pathogens. The combination of defensins with pro- or anti-inflammatory effects can be a potential research direction for the treatment of infection by pathogens. This study aimed to identify whether MSF (Miracle Synergy material made using Filipendula glaberrima), a probiotic lysate of Filipendula glaberrima extracts fermented with Lactiplantibacillus plantarum K8, activates the expression of human ß-defensin (HBD2 and HBD3) to protect the host against pathogens and inhibit inflammation caused by S. aureus, in vitro with Western blot analysis, qRT-PCR and in vivo studies with a mouse model were used to evaluate the effects of MSF. The MSF treatment induced HBD2 and HBD3 expression via the p38 and NF-κB pathways. Furthermore, MSF treatment significantly reduced the expression of pro-inflammatory cytokines (TNF-α, IL-1ß, IL-6, and IL-8), also through p38 and NF-κB in S. aureus-induced inflammatory condition. MSF treatment remarkably reduced erythema in mice ears caused by the injection of S. aureus, while K8 lysate treatment did not initiate a strong recovery. Taken together, MSF induced the expression of HBD2 and HDB3 and activated anti-inflammatory activity more than the probiotic lysates of L. plantarum K8. These findings show that MSF is a potential defensin inducer and anti-inflammatory agent.


Assuntos
NF-kappa B , beta-Defensinas , Animais , Camundongos , Humanos , NF-kappa B/metabolismo , beta-Defensinas/metabolismo , Peptídeos Antimicrobianos , Staphylococcus aureus , Células Cultivadas , Transdução de Sinais , Inflamação/tratamento farmacológico
17.
Mol Cancer ; 22(1): 63, 2023 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-36991428

RESUMO

BACKGROUND: Although metastasis is the foremost cause of cancer-related death, a specialized mechanism that reprograms anchorage dependency of solid tumor cells into circulating tumor cells (CTCs) during metastatic dissemination remains a critical area of challenge. METHODS: We analyzed blood cell-specific transcripts and selected key Adherent-to-Suspension Transition (AST) factors that are competent to reprogram anchorage dependency of adherent cells into suspension cells in an inducible and reversible manner. The mechanisms of AST were evaluated by a series of in vitro and in vivo assays. Paired samples of primary tumors, CTCs, and metastatic tumors were collected from breast cancer and melanoma mouse xenograft models and patients with de novo metastasis. Analyses of single-cell RNA sequencing (scRNA-seq) and tissue staining were performed to validate the role of AST factors in CTCs. Loss-of-function experiments were performed by shRNA knockdown, gene editing, and pharmacological inhibition to block metastasis and prolong survival. RESULTS: We discovered a biological phenomenon referred to as AST that reprograms adherent cells into suspension cells via defined hematopoietic transcriptional regulators, which are hijacked by solid tumor cells to disseminate into CTCs. Induction of AST in adherent cells 1) suppress global integrin/ECM gene expression via Hippo-YAP/TEAD inhibition to evoke spontaneous cell-matrix dissociation and 2) upregulate globin genes that prevent oxidative stress to acquire anoikis resistance, in the absence of lineage differentiation. During dissemination, we uncover the critical roles of AST factors in CTCs derived from patients with de novo metastasis and mouse models. Pharmacological blockade of AST factors via thalidomide derivatives in breast cancer and melanoma cells abrogated CTC formation and suppressed lung metastases without affecting the primary tumor growth. CONCLUSION: We demonstrate that suspension cells can directly arise from adherent cells by the addition of defined hematopoietic factors that confer metastatic traits. Furthermore, our findings expand the prevailing cancer treatment paradigm toward direct intervention within the metastatic spread of cancer.


Assuntos
Neoplasias da Mama , Neoplasias Pulmonares , Melanoma , Células Neoplásicas Circulantes , Camundongos , Animais , Humanos , Feminino , Linhagem Celular Tumoral , Células Neoplásicas Circulantes/patologia , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Melanoma/metabolismo , Neoplasias Pulmonares/patologia , Metástase Neoplásica
18.
J Korean Acad Nurs ; 53(1): 87-100, 2023 Feb.
Artigo em Coreano | MEDLINE | ID: mdl-36898687

RESUMO

PURPOSE: This study aimed to develop a nursing simulation learning module for coronavirus disease 2019 (COVID-19) patient-care and examine its effects on clinical reasoning competence, clinical competence, performance confidence, and anxiety in COVID-19 patient care for nursing students. METHODS: A non-equivalent control group pre- and post-test design was employed. The study participants included 47 nursing students (23 in the experimental group and 24 in the control group) from G City. A simulation learning module for COVID-19 patient-care was developed based on the Jeffries simulation model. The module consisted of a briefing, simulation practice, and debriefing. The effects of the simulation module were measured using clinical reasoning competence, clinical competence, performance confidence, and anxiety in COVID-19 patient-care. Data were analyzed using χ²-test, Fisher's exact test, t-test, Wilcoxon signed-rank test, and Mann-Whitney U test. RESULTS: The levels of clinical reasoning competence, clinical competence, and performance confidence of the experimental group were significantly higher than that of the control group, and the level of anxiety was significantly low after simulation learning. CONCLUSION: The nursing simulation learning module for COVID-19 patient-care is more effective than the traditional method in terms of improving students' clinical reasoning competence, clinical competence, and performance confidence, and reducing their anxiety. The module is expected to be useful for educational and clinical environments as an effective teaching and learning strategy to empower nursing competency and contribute to nursing education and clinical changes.


Assuntos
COVID-19 , Bacharelado em Enfermagem , Estudantes de Enfermagem , Humanos , Competência Clínica , Ansiedade , Assistência ao Paciente , Bacharelado em Enfermagem/métodos
20.
J Environ Manage ; 335: 117493, 2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-36822047

RESUMO

Despite the identification of numerous bioplastic-degrading bacteria, the inconsistent rate of bioplastic degradation under differing cultivation conditions limits the intercomparison of results on biodegradation kinetics. In this study, we isolated a poly (Ɛ-caprolactone) (PCL)-degrading bacterium from a plastic-contaminated landfill and determined the principle-based biodegradation kinetics in a confined model system of varying cultivation conditions. Bacterial degradation of PCL films synthesized by different polymer number average molecular weights (Mn) and concentrations (% w/v) was investigated using both solid and liquid media at various temperatures. As a result, the most active gram-negative bacterial strain at ambient temperature (28 °C), designated CY2-9, was identified as Aquabacterium sp. Based on 16 S rRNA gene analysis. A clear zone around the bacterial colony was apparently exhibited during solid cultivation, and the diameter sizes increased with incubation time. During biodegradation processes in the PCL film, the thermal stability declined (determined by TGA; weight changes at critical temperature), whereas the crystalline proportion increased (determined by DSC; phase transition with temperature increment), implying preferential degradation of the amorphous region in the polymer structure. The surface morphologies (determined by SEM; electron optical system) were gradually hydrolyzed, creating destruction patterns as well as alterations in functional groups on film surfaces (determined by FT-IR; infrared spectrum of absorption or emission). In the kinetic study based on the weight loss of the PCL film (4.5 × 104 Da, 1% w/v), ∼1.5 (>±0.1) × 10-1 day-1 was obtained from linear regression for both solid and liquid media cultivation at 28 °C. The biodegradation efficiencies increased proportionally by a factor of 2.6-7.9, depending on the lower polymer number average molecular weight and lower concentration. Overall, our results are useful for measuring and/or predicting the degradation rates of PCL films by microorganisms in natural environments.


Assuntos
Plásticos , Poliésteres , Poliésteres/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Cinética , Polímeros , Bactérias/metabolismo
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