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1.
Molecules ; 28(12)2023 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-37375365

RESUMO

Among biodegradable polymers, polylactides (PLAs) have attracted considerable interest because the monomer can be produced from renewable resources. Since their initial degradability strongly affects commercial application fields, it is necessary to manage the degradation properties of PLAs to make them more commercially attractive. To control their degradability, poly(lactide-co-glycolide) (PLGA) copolymers of glycolide and isomer lactides (LAs) were synthesized, and their enzymatic and alkaline degradation rates of PLGA monolayers as functions of glycolide acid (GA) composition were systematically investigated by the Langmuir technique. The results showed that the alkaline and enzymatic degradations of PLGA monolayers were faster than those of l-polylactide (l-PLA), even though proteinase K is selectively effective in the l-lactide (l-LA) unit. Alkaline hydrolysis was strongly affected by their hydrophilicity, while the surface pressure of monolayers for enzymatic degradations was a major factor.

2.
Nat Mater ; 18(2): 156-162, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30531848

RESUMO

Bulk and two-dimensional black phosphorus are considered to be promising battery materials due to their high theoretical capacities of 2,600 mAh g-1. However, their rate and cycling capabilities are limited by the intrinsic (de-)alloying mechanism. Here, we demonstrate a unique surface redox molecular-level mechanism of P sites on oxidized black phosphorus nanosheets that are strongly coupled with graphene via strong interlayer bonding. These redox-active sites of the oxidized black phosphorus are confined at the amorphorized heterointerface, revealing truly reversible pseudocapacitance (99% of total stored charge at 2,000 mV s-1). Moreover, oxidized black-phosphorus-based electrodes exhibit a capacitance of 478 F g-1 (four times greater than black phosphorus) with a rate capability of ~72% (compared to 21.2% for black phosphorus) and retention of ~91% over 50,000 cycles. In situ spectroelectrochemical and theoretical analyses reveal a reversible change in the surface electronic structure and chemical environment of the surface-exposed P redox sites.

3.
Small ; 14(39): e1801529, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30175531

RESUMO

Controlled nucleation and growth of metal clusters in metal deposition processes is a long-standing issue for thin-film-based electronic devices. When metal atoms are deposited on solid surfaces, unintended defects sites always lead to a heterogeneous nucleation, resulting in a spatially nonuniform nucleation with irregular growth rates for individual nuclei, resulting in a rough film that requires a thicker film to be deposited to reach the percolation threshold. In the present study, it is shown that substrate-supported graphene promotes the lateral 2D growth of metal atoms on the graphene. Transmission electron microscopy reveals that 2D metallic single crystals are grown epitaxially on supported graphene surfaces while a pristine graphene layer hardly yields any metal nucleation. A surface energy barrier calculation based on density functional theory predicts a suppression of diffusion of metal atoms on electronically perturbed graphene (supported graphene). 2D single Au crystals grown on supported graphene surfaces exhibit unusual near-infrared plasmonic resonance, and the unique 2D growth of metal crystals and self-healing nature of graphene lead to the formation of ultrathin, semitransparent, and biodegradable metallic thin films that could be utilized in various biomedical applications.

4.
Small ; 14(6)2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29211321

RESUMO

Black phosphorus (BP) has drawn enormous attention for both intriguing material characteristics and electronic and optoelectronic applications. In spite of excellent advantages for semiconductor device applications, the performance of BP devices is hampered by the formation of phosphorus oxide on the BP surface under ambient conditions. It is thus necessary to resolve the oxygen-induced degradation on the surface of BP to recover the characteristics and stability of the devices. To solve this problem, it is demonstrated that a 1,2-ethanedithiol (EDT) treatment is a simple and effective way to remove the bubbles formed on the BP surface. The device characteristics of the degraded BP field-effect transistor (FET) are completely recovered to the level of the pristine cases by the EDT treatment. The underlying principle of bubble elimination on the BP surface by the EDT treatment is systematically analyzed by density functional theory calculation, atomic force microscopy, and X-ray photoelectron spectroscopy analysis. In addition, the performance of the hexagonal boron nitride-protected BP FET is completely retained without changing device characteristics even when exposed to 30 d or more in air. The EDT-induced recovering effect will allow a new route for the optimization of electronic and optoelectronic devices based on BP.

5.
Ophthalmology ; 125(5): 708-724, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29331556

RESUMO

Polypoidal choroidal vasculopathy (PCV) is an age-related macular degeneration (AMD) subtype and is seen particularly in Asians. Previous studies have suggested disparity in response to intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents between PCV and typical AMD, and thus, the preferred treatment for PCV has remained unclear. Recent research has provided novel insights into the pathogenesis of PCV, and imaging studies based on OCT suggest that PCV belongs to a spectrum of conditions characterized by pachychoroid, in which disturbance in the choroidal circulation seems to be central to its pathogenesis. Advances in imaging, including enhanced depth imaging, swept-source OCT, en face OCT, and OCT angiography, have facilitated the diagnosis of PCV. Importantly, 2 large, multicenter randomized clinical trials evaluating the safety and efficacy of anti-VEGF monotherapy and combination with photodynamic therapy (PDT) recently reported initial first-year outcomes, providing level I evidence to guide clinicians in choosing the most appropriate therapy for PCV. In this review, we summarize the latest updates in the epidemiologic features, pathogenesis, and advances in imaging and treatment trials, with a focus on the most recent key clinical trials. Finally, we propose current management guidelines and recommendations to help clinicians manage patients with PCV. Remaining gaps in current understanding of PCV, such as significance of polyp closure, high recurrence rate, and heterogeneity within PCV, are highlighted where further research is needed.


Assuntos
Corioide/irrigação sanguínea , Neovascularização de Coroide , Pólipos , Inibidores da Angiogênese/uso terapêutico , Neovascularização de Coroide/diagnóstico , Neovascularização de Coroide/etiologia , Neovascularização de Coroide/terapia , Corantes/administração & dosagem , Angiofluoresceinografia , Humanos , Verde de Indocianina/administração & dosagem , Degeneração Macular/diagnóstico , Degeneração Macular/etiologia , Degeneração Macular/terapia , Fotoquimioterapia , Pólipos/diagnóstico , Pólipos/etiologia , Pólipos/terapia , Tomografia de Coerência Óptica
6.
Sensors (Basel) ; 18(4)2018 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-29597283

RESUMO

The electrocardiogram (ECG) waveform conveys information regarding the electrical property of the heart. The patterns vary depending on the individual heart characteristics. ECG features can be potentially used for biometric recognition. This study presents a new method using the entire ECG waveform pattern for matching and demonstrates that the approach can potentially be employed for individual biometric identification. Multi-cycle ECG signals were assessed using an ECG measuring circuit, and three electrodes can be patched on the wrists or fingers for considering various measurements. For biometric identification, our-fold cross validation was used in the experiments for assessing how the results of a statistical analysis will generalize to an independent data set. Four different pattern matching algorithms, i.e., cosine similarity, cross correlation, city block distance, and Euclidean distances, were tested to compare the individual identification performances with a single channel of ECG signal (3-wire ECG). To evaluate the pattern matching for biometric identification, the ECG recordings for each subject were partitioned into training and test set. The suggested method obtained a maximum performance of 89.9% accuracy with two heartbeats of ECG signals measured on the wrist and 93.3% accuracy with three heartbeats for 55 subjects. The performance rate with ECG signals measured on the fingers improved up to 99.3% with two heartbeats and 100% with three heartbeats of signals for 20 subjects.


Assuntos
Identificação Biométrica , Algoritmos , Eletrocardiografia , Frequência Cardíaca , Humanos , Processamento de Sinais Assistido por Computador
7.
Sensors (Basel) ; 17(6)2017 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-28555031

RESUMO

Dynamic task allocation is a necessity in a group of robots. Each member should decide its own task such that it is most commensurate with its current state in the overall system. In this work, the response threshold model is applied to a dynamic foraging task. Each robot employs a task switching function based on the local task demand obtained from the surrounding environment, and no communication occurs between the robots. Each individual member has a constant-sized task demand history that reflects the global demand. In addition, it has response threshold values for all of the tasks and manages the task switching process depending on the stimuli of the task demands. The robot then determines the task to be executed to regulate the overall division of labor. This task selection induces a specialized tendency for performing a specific task and regulates the division of labor. In particular, maintaining a history of the task demands is very effective for the dynamic foraging task. Various experiments are performed using a simulation with multiple robots, and the results show that the proposed algorithm is more effective as compared to the conventional model.

8.
Sensors (Basel) ; 17(12)2017 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-29186836

RESUMO

This paper presents a distributed coordination methodology for multi-robot systems, based on nearest-neighbor interactions. Among many interesting tasks that may be performed using swarm robots, we propose a biologically-inspired control law for a shepherding task, whereby a group of external agents drives another group of agents to a desired location. First, we generated sheep-like robots that act like a flock. We assume that each agent is capable of measuring the relative location and velocity to each of its neighbors within a limited sensing area. Then, we designed a control strategy for shepherd-like robots that have information regarding where to go and a steering ability to control the flock, according to the robots' position relative to the flock. We define several independent behavior rules; each agent calculates to what extent it will move by summarizing each rule. The flocking sheep agents detect the steering agents and try to avoid them; this tendency leads to movement of the flock. Each steering agent only needs to focus on guiding the nearest flocking agent to the desired location. Without centralized coordination, multiple steering agents produce an arc formation to control the flock effectively. In addition, we propose a new rule for collecting behavior, whereby a scattered flock or multiple flocks are consolidated. From simulation results with multiple robots, we show that each robot performs actions for the shepherding behavior, and only a few steering agents are needed to control the whole flock. The results are displayed in maps that trace the paths of the flock and steering robots. Performance is evaluated via time cost and path accuracy to demonstrate the effectiveness of this approach.

9.
Nanotechnology ; 27(49): 495401, 2016 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-27827350

RESUMO

The advent of advanced electrode materials has led to performance enhancement of traditional lithium ion batteries (LIBs). We present novel binder-free MoS2 coated three-dimensional carbon nanotubes (3D CNTs) as an anode in LIBs. Scanning transmission electron microscopy analysis shows that vertically oriented MoS2 nanoflakes are strongly bonded to CNTs, which provide a high surface area and active electrochemical sites, and enhanced ion conductivity at the interface. The electrochemical performance shows a very high areal capacity of ~1.65 mAh cm-2 with an areal density of ~0.35 mg cm-2 at 0.5 C rate and coulombic efficiency of ~99% up to 50 cycles. The unique architecture of 3D CNTs-MoS2 is indicative to be a promising anode for next generation Li-ion batteries with high capacity and long cycle life.

10.
J Nanosci Nanotechnol ; 16(3): 3098-101, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27455767

RESUMO

This study investigated the surface structure of fluorocarbon end-capped l-poly(lactide)s (F-PLLA) with different fluorocarbon lengths by electron spectroscopy for chemical analysis (ESCA). Fluorocarbon chains of three lengths (F(CF2)n(CH2)2, where n = 6, 8, and 10) have been synthesized as the terminal group to PLLA. Angular dependent ESCA revealed that the fluorocarbon groups are segregated at the surface. Further, the results show the surface coverage of fluorocarbon groups rapidly increases with increasing the length of fluorocarbon end groups (synergy effect). The surface composition of F-PLLAs can be controlled by changing the length of fluorocarbon.


Assuntos
Fluorocarbonos/química , Polímeros/química , Espectroscopia de Ressonância Magnética , Propriedades de Superfície
11.
Korean J Parasitol ; 54(3): 329-34, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27417089

RESUMO

Trichomoniasis caused by Trichomonas vaginalis is a common sexually transmitted disease. Its association with several health problems, including preterm birth, pelvic inflammatory disease, cervical cancer, and transmission of human immunodeficiency virus, emphasizes the importance of improved access to early and accurate detection of T. vaginalis. In this study, a rapid and efficient loop-mediated isothermal amplification-based method for the detection of T. vaginalis was developed and validated, using vaginal swab specimens from subjects suspected to have trichomoniasis. The LAMP assay targeting the actin gene was highly sensitive with detection limits of 1 trichomonad and 1 pg of T. vaginalis DNA per reaction, and specifically amplified the target gene only from T. vaginalis. Validation of this assay showed that it had the highest sensitivity and better agreement with PCR (used as the gold standard) compared to microscopy and multiplex PCR. This study showed that the LAMP assay, targeting the actin gene, could be used to diagnose early infections of T. vaginalis. Thus, we have provided an alternative molecular diagnostic tool and a point-of-care test that may help to prevent trichomoniasis transmission and associated complications.


Assuntos
Actinas/genética , DNA de Protozoário/genética , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Vaginite por Trichomonas/diagnóstico , Trichomonas vaginalis/isolamento & purificação , Feminino , Humanos , Sistemas Automatizados de Assistência Junto ao Leito , Sensibilidade e Especificidade , Vaginite por Trichomonas/parasitologia , Trichomonas vaginalis/genética
12.
Korean J Parasitol ; 54(1): 75-80, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26951983

RESUMO

This study explored epidemiological trends in trichomoniasis in Daegu, South Korea. Wet mount microscopy, PCR, and multiplex PCR were used to test for Trichomonas vaginalis in vaginal swab samples obtained from 621 women visiting 2 clinics in Daegu. Of the 621 women tested, microscopy detected T. vaginalis in 4 (0.6%) patients, PCR detected T. vaginalis in 19 (3.0%) patients, and multiplex PCR detected T. vaginalis in 12 (1.9%) patients. Testing via PCR demonstrated high sensitivity and high negative predictive value for T. vaginalis. Among the 19 women who tested positive for T. vaginalis according to PCR, 94.7% (18/19) reported vaginal signs and symptoms. Notably, more than 50% of T. vaginalis infections occurred in females younger than 30 years old, and 58% were unmarried. Multiplex PCR, which simultaneously detects pathogens from various sexually transmitted infections, revealed that 91.7% (11/12) of patients were infected with 2 or more pathogens. Mycoplasma hominis was the most prevalent co-infection pathogen with T. vaginalis, followed by Ureaplasma urealyticum and Chlamydia trachomatis. Our results indicate that PCR and multiplex PCR are the most sensitive tools for T. vaginalis diagnosis, rather than microscopy which has been routinely used to detect T. vaginalis infections in South Korea. Therefore, clinicians should take note of the high prevalence of T. vaginalis infections among adolescent and young women in order to prevent persistent infection and transmission of this disease.


Assuntos
Tricomoníase/epidemiologia , Adolescente , Adulto , Instituições de Assistência Ambulatorial/estatística & dados numéricos , Feminino , Humanos , Microscopia/normas , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase Multiplex/normas , Reação em Cadeia da Polimerase/normas , Valor Preditivo dos Testes , Prevalência , República da Coreia/epidemiologia , Sensibilidade e Especificidade , Tricomoníase/prevenção & controle , Trichomonas vaginalis/fisiologia , Esfregaço Vaginal/normas , Adulto Jovem
13.
Ophthalmology ; 122(7): 1402-15, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25983216

RESUMO

OBJECTIVE: The primary study hypothesis was that ranibizumab 0.5 mg monotherapy or combined with laser is superior to laser monotherapy based on mean average change in best-corrected visual acuity (BCVA) over 12 months in Asian patients with visual impairment resulting from diabetic macular edema (DME). DESIGN: A 12-month, randomized, double-masked, multicenter, laser-controlled, phase III study. PARTICIPANTS: Three hundred ninety-six patients aged ≥18 years, with type 1 or 2 diabetes mellitus, BCVA of 78-39 Early Treatment Diabetic Retinopathy Study (ETDRS) letters, and visual impairment resulting from DME. METHODS: Patients were randomized to ranibizumab + sham laser (n = 133), ranibizumab + active laser (n = 132), or sham injection + active laser (n = 131). Ranibizumab/sham injections were administered on day 1 and continued monthly. As of month 3, monthly injections were continued if stable vision was not reached. Treatment was reinitiated if BCVA decreased because of DME progression. Active/sham laser was administered on day 1 and thereafter according to ETDRS guidelines. MAIN OUTCOME MEASURES: Average change in BCVA from baseline to months 1 through 12, central retinal subfield thickness (CRST), and safety over 12 months. RESULTS: Ranibizumab monotherapy or combined with laser was superior to laser in improving mean average change in BCVA from baseline to months 1 through 12 (+5.9 and +5.7 vs +1.4 letters). At month 12, greater proportion of patients gained ≥15 letters with ranibizumab and ranibizumab + laser compared with laser (18.8% and 17.8% vs 7.8%). Mean CRST reduced significantly from baseline to month 12 with ranibizumab (-134.6 µm) and ranibizumab + laser (-171.8 µm) versus laser (-57.2 µm). Patients received a mean of 7.8 and 7.0 ranibizumab injections in the ranibizumab and ranibizumab + laser arms, respectively, and 1.5-1.9 active laser across treatment arms over 12 months. Conjunctival hemorrhage was the most common ocular, whereas nasopharyngitis and hypertension were the most common nonocular adverse events. Ranibizumab was not associated with any cases of cerebrovascular hemorrhage and cerebrovascular ischemia. No death related to study treatment was reported. CONCLUSIONS: Ranibizumab monotherapy or combined with laser showed superior BCVA improvements over laser treatment alone in Asian patients with visual impairment resulting from DME. No new ocular or nonocular safety findings were observed and treatment was well tolerated over 12 months.


Assuntos
Inibidores da Angiogênese/uso terapêutico , Anticorpos Monoclonais Humanizados/uso terapêutico , Retinopatia Diabética/terapia , Fotocoagulação a Laser , Edema Macular/terapia , Idoso , Povo Asiático/etnologia , Terapia Combinada , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 2/complicações , Retinopatia Diabética/tratamento farmacológico , Retinopatia Diabética/etnologia , Retinopatia Diabética/cirurgia , Método Duplo-Cego , Feminino , Humanos , Injeções Intravítreas , Edema Macular/tratamento farmacológico , Edema Macular/etnologia , Edema Macular/cirurgia , Masculino , Pessoa de Meia-Idade , Prognóstico , Ranibizumab , Tomografia de Coerência Óptica , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Acuidade Visual/fisiologia
14.
Soft Matter ; 11(22): 4402-7, 2015 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-25959746

RESUMO

Hybrid assemblies consisting of metal nanoparticles (NPs) and fluorophores are quite interesting because the intrinsic properties of fluorophores can be engineered in the assembled structure. In this regard, we utilized the self-segregation properties of block copolymer micelles to organize metal NPs and fluorophores simultaneously in a specific arrangement. From the viewpoint of assembly methods, we first encapsulated Au NPs in the PS cores of polystyrene-block-poly(acrylic acid) (PS-PAA) micelles. Then, positively charged fluorescent dyes of rhodamine 123 (R123) were bound to the negatively charged PAA coronas by electrostatic interactions. Since carboxylic acid in the PAA block is a weak acid, the degree of R123 binding to PS-PAA micelles can be adjusted by varying the pH of the solution. Therefore, by changing the pH, we were able to control the assembly and disassembly of R123 molecules to PS-PAA micelles and the corresponding change in the fluorescence signal.

15.
Malar J ; 13: 248, 2014 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-24981710

RESUMO

BACKGROUND: Malaria that is caused by Plasmodium vivax is the most widely distributed human malaria. Its recent resurgence in many parts of the world, including the Republic of Korea (ROK), emphasizes the importance of improved access to the early and accurate detection of P. vivax to reduce disease burden. In this study, a rapid and efficient loop-mediated isothermal amplification (LAMP)-based method was developed and validated using blood samples from malaria-suspected patients. METHOD: A LAMP assay targeting the α-tubulin gene for the detection of P. vivax was developed with six primers that recognize different regions of the target gene. The diagnostic performance of the α-tubulin LAMP assay was compared to three other tests: microscopic examinations, rapid diagnostic tests (RDTs), and nested polymerase chain reactions (PCRs) using 177 whole blood specimens obtained from ROK military personnel from May to December 2011. RESULTS: The α-tubulin LAMP assay was highly sensitive with a detection limit of 100 copies of P. vivax α-tubulin gene per reaction within 50 min. It specifically amplified the target gene only from P. vivax. Validation of the α-tubulin LAMP assay showed that the assay had the highest sensitivity (P < 0.001 versus microscopy; P = 0.0023 versus RDT) when nested PCR was used as the gold standard and better agreement (concordance: 94.9%, kappa value: 0.865) with nested PCR than RDT and microscopy. A Receiver Operation Characteristics analysis showed that the diagnostic accuracy of the α-tubulin LAMP assay for vivax malaria was higher (Area Under Curve = 0.908) than RDT and microscopy. CONCLUSION: This study showed that the P. vivax α-tubulin LAMP assay, which can be used to diagnose early infections of vivax malaria, is an alternative molecular diagnostic tool and a point-of-care test that may help to prevent transmission in endemic areas.


Assuntos
DNA de Protozoário/sangue , Malária Vivax/sangue , Técnicas de Amplificação de Ácido Nucleico/métodos , Parasitemia/sangue , Plasmodium vivax/isolamento & purificação , Proteínas de Protozoários/genética , Tubulina (Proteína)/genética , Adulto , Área Sob a Curva , Corantes Azur , Sequência de Bases , Cromatografia de Afinidade , DNA de Protozoário/genética , Humanos , Malária Vivax/diagnóstico , Malária Vivax/parasitologia , Masculino , Dados de Sequência Molecular , Parasitemia/diagnóstico , Parasitemia/parasitologia , Plasmodium vivax/genética , Sistemas Automatizados de Assistência Junto ao Leito , Reação em Cadeia da Polimerase , Curva ROC , Sensibilidade e Especificidade , Alinhamento de Sequência , Homologia de Sequência do Ácido Nucleico , Coloração e Rotulagem
16.
Int J Biol Macromol ; 262(Pt 2): 130135, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38354938

RESUMO

Electrospinning is the simplest technique to produce ultrathin nanofibers, which enables the use of nanotechnology in various applications. Nanofibrous materials produced through electrospinning have garnered significant attention in biomedical applications due to their unique properties and versatile potential. In recent years, there has been a growing emphasis on incorporating sustainability principles into material design and production. However, electrospun nanofibers, owing to their reliance on solvents associated with significant drawbacks like toxicity, flammability, and disposal challenges, frequently fall short of meeting environmentally friendly standards. Due to the limited solvent choices and heightened concerns for safety and hygiene in modern living, it becomes imperative to carefully assess the implications of employing electrospun nanofibers in diverse applications and consumer products. This systematic review aims to comprehensively assess the current state of research and development in the field of "green and natural" electrospun polymer nanofibers as well as more fascinating and eco-friendly commercial techniques, solvent preferences, and other green routes that respect social and legal restrictions tailored for biomedical applications. We explore the utilization of biocompatible and biodegradable polymers sourced from renewable feedstocks, eco-friendly processing techniques, and the evaluation of environmental impacts. Our review highlights the potential of green and natural electrospun nanofibers to address sustainability concerns while meeting the demanding requirements of various biomedical applications, including tissue engineering, drug delivery, wound healing, and diagnostic platforms. We analyze the advantages, challenges, and future prospects of these materials, offering insights into the evolving landscape of environmentally responsible nanofiber technology in the biomedical field.


Assuntos
Nanofibras , Engenharia Tecidual/métodos , Sistemas de Liberação de Medicamentos , Polímeros , Solventes
17.
Adv Biol (Weinh) ; 8(6): e2300375, 2024 06.
Artigo em Inglês | MEDLINE | ID: mdl-38548666

RESUMO

In anti-cancer metastasis treatment, precise drug delivery to cancer cells remains a challenge. Innovative nanocomposites are developed to tackle these issues effectively. The approach involves the creation of manganese oxide (Mn3O4) nanoparticles (NPs) and their functionalization using trisodium citrate to yield functionalized Mn3O4 NPs (F-Mn3O4 NPs), with enhanced water solubility, stability, and biocompatibility. Subsequently, the chemotherapeutic drug doxorubicin (DOX) is encapsulated with Mn3O4 NPs, resulting in DOX/Mn3O4 NPs. To achieve cell-specific targeting, These NPs are coated with HeLa cell membranes (HCM), forming HCM/DOX/Mn3O4. For further refinement, a transferrin (Tf) receptor is integrated with cracked HCM to create Tf-HCM/DOX/Mn3O4 nanocomposites (NC) with specific cell membrane targeting capabilities. The resulting Tf-HCM/DOX/Mn3O4 NC exhibits excellent drug encapsulation efficiency (97.5%) and displays triggered drug release when exposed to NIR laser irradiation in the tumor's environment (pH 5.0 and 6.5). Furthermore, these nanocomposites show resistance to macrophage uptake and demonstrate homotypic cancer cell targeting specificity, even in the presence of other tumor cells. In vitro toxicity tests show that Tf-HCM/DOX/Mn3O4 NC achieves significant anticancer activity against HeLa and BT20 cancer cells, with percentages of 76.46% and 71.36%, respectively. These results indicate the potential of Tf-HCM/DOX/Mn3O4 NC as an effective nanoplatform for chemo-photothermal therapy.


Assuntos
Membrana Celular , Doxorrubicina , Sistemas de Liberação de Medicamentos , Compostos de Manganês , Nanocompostos , Óxidos , Humanos , Compostos de Manganês/química , Compostos de Manganês/farmacologia , Nanocompostos/química , Doxorrubicina/farmacologia , Doxorrubicina/química , Doxorrubicina/administração & dosagem , Células HeLa , Óxidos/química , Óxidos/farmacologia , Sistemas de Liberação de Medicamentos/métodos , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Liberação Controlada de Fármacos , Antineoplásicos/farmacologia , Antineoplásicos/administração & dosagem , Antineoplásicos/química , Neoplasias/tratamento farmacológico , Neoplasias/patologia
18.
ACS Appl Mater Interfaces ; 16(3): 3694-3702, 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38214703

RESUMO

Doping is one of the most difficult technological challenges for realizing reliable two-dimensional (2D) material-based semiconductor devices, arising from their ultrathinness. Here, we systematically investigate the impact of different types of nonstoichiometric solid MOx (M are W or Mo) dopants obtained by oxidizing transition metal dichalcogenides (TMDs: WSe2 or MoS2) formed on graphene FETs, which results in p-type doping along with disorders. From the results obtained in this study, we were able to suggest an analytical technique to optimize the optimal UV-ozone (UVO) treatment to achieve high p-type doping concentration in graphene FETs (∼2.5 × 1013 cm-2 in this study) without generating defects, mainly by analyzing the time dependency of D and D' peaks measured by Raman spectroscopy. Furthermore, an analysis of the structure of graphene sheets using TEM indicates that WOx plays a better protective role in graphene, compared to MoOx, suggesting that WOx is more effective for preventing the degradation of graphene during UVO treatment. To enhance the practical application aspect of our work, we have fabricated a graphene photodetector by selectively doping the graphene through oxidized TMDs, creating a p-n junction, which resulted in improved photoresponsivity compared to the intrinsic graphene device. Our results offer a practical guideline for the utilization of surface charge transfer doping of graphene toward CMOS applications.

19.
J Interpers Violence ; : 8862605231218222, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-38084385

RESUMO

Although general strain theory (GST) highlights the mediating role of anger between strain and violent behavior, the extant body of literature has been criticized for lack of rigorous testing of the mediating role of anger and lack of application in different cultural contexts. To cover this research gap, the current study investigated the mediating effect of anger between primary sources of strain of South Korean adolescents (i.e., parental abuse, academic-related strain, and negative relations to teacher) and violent behavior. Using structural equation modeling based on a nationally representative longitudinal dataset (n = 3,120), this study found a significant mediating role of anger in connecting strain and violent behavior of South Korean adolescents. Results from the present study support the main proposition of the GST on the mediating role of anger and its applicability in a cross-cultural context. Theoretical and practical implications are discussed.

20.
Polymers (Basel) ; 15(21)2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37959916

RESUMO

The novel ultra-high molecular weight polypropylene (UHMWPP) as a dispersed component was melt blended with conventional high-density polyethylene (PE) and maleic anhydride grafted-polyethylene (mPE) in different proportions through a kneader. Ultra-high molecular weight polypropylene is a high-performance polymer material that has excellent mechanical properties and toughness compared to other polymers. Mechanical, thermal, and rheological properties were presented for various UHMWPP loadings, and correlations between mechanical and rheological properties were examined. Optimal comprehensive mechanical properties are achieved when the UHMWPP content reaches approximately 50 wt%, although the elongation properties do not match those of pure PE or mPE. However, it is worth noting that the elongation properties of these blends did not match those of PE or mPE. Particularly, for the PE/UHMWPP blends, a significant drop in tensile strength was observed as the UHMWPP content decreased (from 30.24 MPa for P50U50 to 13.12 MPa for P90U10). In contrast, the mPE/UHMWPP blends demonstrated only minimal changes in tensile strength (ranging from 29 MPa for mP50U50 to 24.64 MPa for mP90U10) as UHMWPP content varied. The storage modulus of the PE/UHMWPP blends increased drastically with the UHMWPP content due to the UHMWPP chain entanglements and rigidity. Additionally, we noted a substantial reduction in the melt index of the blend system when the UHMWPP content exceeded 10% by weight.

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