Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 233
Filtrar
1.
Sensors (Basel) ; 24(9)2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38732784

RESUMO

Artificial retinas have revolutionized the lives of many blind people by enabling their ability to perceive vision via an implanted chip. Despite significant advancements, there are some limitations that cannot be ignored. Presenting all objects captured in a scene makes their identification difficult. Addressing this limitation is necessary because the artificial retina can utilize a very limited number of pixels to represent vision information. This problem in a multi-object scenario can be mitigated by enhancing images such that only the major objects are considered to be shown in vision. Although simple techniques like edge detection are used, they fall short in representing identifiable objects in complex scenarios, suggesting the idea of integrating primary object edges. To support this idea, the proposed classification model aims at identifying the primary objects based on a suggested set of selective features. The proposed classification model can then be equipped into the artificial retina system for filtering multiple primary objects to enhance vision. The suitability of handling multi-objects enables the system to cope with real-world complex scenarios. The proposed classification model is based on a multi-label deep neural network, specifically designed to leverage from the selective feature set. Initially, the enhanced images proposed in this research are compared with the ones that utilize an edge detection technique for single, dual, and multi-object images. These enhancements are also verified through an intensity profile analysis. Subsequently, the proposed classification model's performance is evaluated to show the significance of utilizing the suggested features. This includes evaluating the model's ability to correctly classify the top five, four, three, two, and one object(s), with respective accuracies of up to 84.8%, 85.2%, 86.8%, 91.8%, and 96.4%. Several comparisons such as training/validation loss and accuracies, precision, recall, specificity, and area under a curve indicate reliable results. Based on the overall evaluation of this study, it is concluded that using the suggested set of selective features not only improves the classification model's performance, but aligns with the specific problem to address the challenge of correctly identifying objects in multi-object scenarios. Therefore, the proposed classification model designed on the basis of selective features is considered to be a very useful tool in supporting the idea of optimizing image enhancement.


Assuntos
Inteligência Artificial , Redes Neurais de Computação , Retina , Retina/diagnóstico por imagem , Humanos , Aumento da Imagem/métodos , Algoritmos , Processamento de Imagem Assistida por Computador/métodos , Próteses Visuais
2.
ACS Nano ; 18(19): 12325-12332, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38686926

RESUMO

Three-dimensional (3D) microfabrication techniques play a crucial role across various research fields. These techniques enable the creation of functional 3D structures on the microscale, unlocking possibilities for diverse applications. However, conventional fabrication methods have limits in producing complex 3D structures, which require numerous fabrication steps that increase the costs. Graphene is an atomically thin material known for its deformability and impermeability to small gases and molecules, including reactive gases like XeF2. These features make graphene a potential candidate as an etch mask for 3D microfabrication. Here, we report the fabrication of various 3D microstructures using graphene etch masks directly grown and patterned on a Si substrate. The patterned graphene deforms and wraps the etched structures, allowing for the fabrication of complicated 3D microstructures, such as mushroom-like and step-like microstructures. As a practical demonstration of the graphene etch mask, we fabricate an omniphobic surface of reentrant 3D structures on a Si substrate. Our work provides a method for fabricating complex 3D microstructures using a graphene etch mask, contributing to advancements in etching and fabrication processes.

3.
J Neuroeng Rehabil ; 21(1): 58, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38627779

RESUMO

BACKGROUND: Identification of cortical loci for lower limb movements for stroke rehabilitation is crucial for better rehabilitation outcomes via noninvasive brain stimulation by targeting the fine-grained cortical loci of the movements. However, identification of the cortical loci for lower limb movements using functional MRI (fMRI) is challenging due to head motion and difficulty in isolating different types of movement. Therefore, we developed a custom-made MR-compatible footplate and leg cushion to identify the cortical loci for lower limb movements and conducted multivariate analysis on the fMRI data. We evaluated the validity of the identified loci using both fMRI and behavioral data, obtained from healthy participants as well as individuals after stroke. METHODS: We recruited 33 healthy participants who performed four different lower limb movements (ankle dorsiflexion, ankle rotation, knee extension, and toe flexion) using our custom-built equipment while fMRI data were acquired. A subgroup of these participants (Dataset 1; n = 21) was used to identify the cortical loci associated with each lower limb movement in the paracentral lobule (PCL) using multivoxel pattern analysis and representational similarity analysis. The identified cortical loci were then evaluated using the remaining healthy participants (Dataset 2; n = 11), for whom the laterality index (LI) was calculated for each lower limb movement using the cortical loci identified for the left and right lower limbs. In addition, we acquired a dataset from 15 individuals with chronic stroke for regression analysis using the LI and the Fugl-Meyer Assessment (FMA) scale. RESULTS: The cortical loci associated with the lower limb movements were hierarchically organized in the medial wall of the PCL following the cortical homunculus. The LI was clearer using the identified cortical loci than using the PCL. The healthy participants (mean ± standard deviation: 0.12 ± 0.30; range: - 0.63 to 0.91) exhibited a higher contralateral LI than the individuals after stroke (0.07 ± 0.47; - 0.83 to 0.97). The corresponding LI scores for individuals after stroke showed a significant positive correlation with the FMA scale for paretic side movement in ankle dorsiflexion (R2 = 0.33, p = 0.025) and toe flexion (R2 = 0.37, p = 0.016). CONCLUSIONS: The cortical loci associated with lower limb movements in the PCL identified in healthy participants were validated using independent groups of healthy participants and individuals after stroke. Our findings suggest that these cortical loci may be beneficial for the neurorehabilitation of lower limb movement in individuals after stroke, such as in developing effective rehabilitation interventions guided by the LI scores obtained for neuronal activations calculated from the identified cortical loci across the paretic and non-paretic sides of the brain.


Assuntos
Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Humanos , Movimento/fisiologia , Extremidade Inferior , Imageamento por Ressonância Magnética
4.
Medicine (Baltimore) ; 103(3): e37016, 2024 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-38241547

RESUMO

BACKGROUND: Cyclin B1 and cyclin B2 are key regulators of cell cycle progression and have been implicated in the prognostic significance of various cancers. This meta-analysis aimed to evaluate the prognostic value of cyclin B1 and B2 expression in breast cancer. METHODS: A comprehensive literature search was conducted on Pubmed, Embase, MEDLINE, Web of Science, and Cochrane library. Studies with survival data and clinicopathological parameters associated with cyclin B1 and B2 or CCNB1 and CCNB2 genes were included. Survival data and clinicopathological parameters associated with cyclin B1 and B2 expression were extracted. Pooled hazard ratios and odds ratios with 95% confidence intervals were calculated. Subgroup analysis was conducted to assess heterogeneity. Publication bias was evaluated. RESULTS: A total of 23 studies were included in the analysis. High expression of cyclin B1 was significantly associated with worse overall survival (hazard ratio [HR] = 1.69, P < .01), disease-specific survival (HR = 1.71, P < .01), and disease-free survival (HR = 2.01, P = .01). High expression of cyclin B2 was associated with worse disease-specific survival (HR = 2.46, P = .02). Clinicopathological parameters did not show significant associations with cyclin B1 and B2 expressions. When data on cyclin B1 and B2 were combined, a significant age-related difference was found (odds ratio = 0.62, P = .04). CONCLUSIONS: This meta-analysis provides evidence supporting the prognostic significance of cyclin B1 and B2 expression in breast cancer. High expression of cyclin B1 and B2 is associated with worse survival, indicating their potential as prognostic markers in breast cancer.


Assuntos
Neoplasias da Mama , Feminino , Humanos , Neoplasias da Mama/genética , Ciclina B1 , Ciclina B2/genética , Prognóstico , Modelos de Riscos Proporcionais
5.
Nano Lett ; 24(4): 1454-1461, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38214495

RESUMO

Two-dimensional (2D) materials are outstanding candidates for stretchable electronics, but a significant challenge is their heterogeneous integration into stretchable geometries on soft substrates. Here, we demonstrate a strategy for stretchable thin film transistors (2D S-TFT) based on wrinkled heterostructures on elastomer substrates where 2D materials formed the gate, source, drain, and channel and characterized them with Raman spectroscopy and transport measurements. The 2D S-TFTs had initial mobility of 4.9 ± 0.7 cm2/(V s). The wrinkling reduced the strain transferred into the 2D materials by a factor of 50, allowing a substrate stretch of up to 23% that could be cycled thousands of times without electrical degradation. The stretch did not alter the mobility but did lead to strain-induced threshold voltage shifts by ΔVT = -1.9 V. These 2D S-TFTs form the foundation for stretchable integrated circuits and enable investigations of the impact of heterogeneous strain on electron transport.

6.
Small ; : e2307830, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38263814

RESUMO

Combining an electrochemically stable material onto the surface of a catalyst can improve the durability of a transition metal catalyst, and enable the catalyst to operate stably at high current density. Herein, the contribution of the N-doped carbon shell (NCS) to the electrochemical properties is evaluated by comparing the characteristics of the Ni3 Fe@NCS catalyst with the N-doped carbon shell, and the Ni3 Fe catalyst. The synthesized Ni3 Fe@NCS catalyst has a distinct overpotential difference from the Ni3 Fe catalyst (ηOER = 468.8 mV, ηHER = 462.2 mV) at (200 and -200) mA cm-2 in 1 m KOH. In stability test at (10 and -10) mA cm-2 , the Ni3 Fe@NCS catalyst showed a stability of (95.47 and 99.6)%, while the Ni3 Fe catalyst showed a stability of (72.4 and 95.9)%, respectively. In addition, the in situ X-ray Absorption Near Edge Spectroscopy (XANES) results show that redox reaction appeared in the Ni3 Fe catalyst by applying voltages of (1.7 and -0.48) V. The decomposition of nickel and iron due to the redox reaction is detected as a high ppm concentration in the Ni3 Fe catalyst through Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) analysis. This work presents the strategy and design of a next-generation electrochemical catalyst to improve the electrocatalytic properties and stability.

7.
Ultrasonography ; 43(1): 35-46, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38029736

RESUMO

PURPOSE: Acoustic streaming induced by applying transcranial focused ultrasound (FUS) promotes localized advective solute transport in the brain and has recently garnered research interest for drug delivery and enhancement of brain waste clearance. The acoustic streaming behavior in brain tissue is difficult to model numerically and thus warrants an in vitro examination of the effects of using different sonication parameters, in terms of frequency, intensity, and pulse duration (PD). METHODS: Melamine and polyvinyl alcohol (PVA) foams were used to mimic the porous brain tissue, which contains leptomeningeal fenestrations and perivascular space, while agar hydrogel was used to emulate denser neuropil. FUS was delivered to these media, which were immersed in a phosphate-buffered saline containing toluidine blue O dye, across various frequencies (400, 500, and 600 kHz; applicable to transcranial delivery) in a pulsed mode at two different spatialpeak pulse-average intensities (3 and 4 W/cm2). RESULTS: Image analysis showed that the use of 400 kHz yielded the greatest dye infiltration in melamine foam, while sonication had no impact on infiltration in the agar hydrogel due to the dominance of diffusional transport. Using a fixed spatial-peak temporal-average intensity of 0.4 W/cm2 at 400 kHz, a PD of 75 ms resulted in the greatest infiltration depth in both melamine and PVA foams among the tested range (50-150 ms). CONCLUSION: These findings suggest the existence of a specific frequency and PD that induce greater enhancement of solute/fluid movement, which may contribute to eventual in vivo applications in promoting waste clearance from the brain.

8.
Anticancer Res ; 43(11): 4793-4800, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37909989

RESUMO

BACKGROUND/AIM: We examined the effect of low-intensity focused ultrasound (FUS) on unbinding cisplatin from plasma proteins and enhancing its chemotherapeutic efficacy using a mouse model of xenograft human cervical cancer. MATERIALS AND METHODS: FUS, operating in a pulsed mode, was applied to a dialysis cassette immersed in a normal saline bath containing both bovine serum albumin (BSA) and cisplatin, and the unbound level of cisplatin diffused into the cassette was measured. To assess the in vivo efficacy of the technique, athymic nu/nu mice were inoculated with human cervical cancer cells under four different combinatory conditions, with and without the administration of cisplatin and FUS. FUS was delivered to the tumor mass for 1 h across four separate sessions spanning a period of 10 days, following the intraperitoneal injection of cisplatin. RESULTS: In vitro equilibrium dialysis revealed that non-thermal application of FUS increased the concentration of unbound cisplatin compared to cassettes that were not exposed to sonication, suggesting successful unbinding. Assessment of tumor growth in vivo showed that FUS following cisplatin administration resulted in a significant reduction in tumor growth, whereas the administration of cisplatin alone exhibited plateau growth. Without administration of cisplatin, equivalent rates of aggressive tumor growth were observed regardless of the application of FUS. CONCLUSION: Pulsed application of FUS can unbind cisplatin from albumin and enhance its tumoricidal effects in cervical cancer. Further assessment of intratumoral/systemic cisplatin concentration is required to quantify its selective delivery to the tumor.


Assuntos
Neoplasias do Colo do Útero , Humanos , Feminino , Neoplasias do Colo do Útero/tratamento farmacológico , Xenoenxertos , Cisplatino/farmacologia , Transplante Heterólogo , Acústica
9.
Diagnostics (Basel) ; 13(20)2023 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-37892079

RESUMO

(1) Background: High-grade serous ovarian carcinoma (HGSOC) is an aggressive subtype of ovarian cancer. Recent advances have introduced prognostic markers and targeted therapies. Programmed cell death ligand 1 (PD-L1) has emerged as a potential biomarker for HGSOC, with implications for prognosis and targeted therapy eligibility; (2) Methods: A literature search was conducted on major databases, and extracted data were categorized and pooled. Subgroup analysis was performed for studies with high heterogeneity. (3) Results: Data from 18 eligible studies were categorized and pooled based on PD-L1 scoring methods, survival analysis types, and endpoints. The result showed an association between high PD-L1 expression and a favorable prognosis in progression-free survival (HR = 0.53, 95% CI = 0.35-0.78, p = 0.0015). Subgroup analyses showed similar associations in subgroups of neoadjuvant chemotherapy patients (HR = 0.6, 95% CI = 0.4-0.88, p = 0.009) and European studies (HR = 0.59, 95% CI = 0.42-0.82, p = 0.0017). In addition, subgroup analyses using data from studies using FDA-approved PD-L1 antibodies suggested a significant association between favorable prognosis and high PD-L1 expression in a subgroup including high and low stage data in overall survival data (HR = 0.46, 95% CI = 0.3-0.73, p = 0.0009). (4) Conclusions: This meta-analysis revealed a potential association between high PD-L1 expression and favorable prognosis. However, caution is warranted due to several limitations. Validation via large-scale studies, with mRNA analysis, whole tissue sections, and assessments using FDA-approved antibodies is needed.

10.
J Health Econ ; 92: 102829, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37865028

RESUMO

We use Nielsen Homescan data to examine whether the incidence of cigarette taxes on menthol products varies with race. We find that taxes are shifted at significantly lower rates to Black smokers of menthol cigarettes than any other smokers. One possible explanation is that the industry targets price promotions to Black menthol smokers because they tend to be more responsive to cigarette prices relative to other smokers. We find evidence that Black smokers receive significantly more price discounts for menthol products than white menthol smokers. Our findings indicate that increasing cigarette taxes would effectively reduce menthol smoking among Black Americans because tax pass-through rate for Black menthol smokers is still substantially above zero.


Assuntos
Mentol , Produtos do Tabaco , Humanos , Incidência , Fumar/epidemiologia , Impostos
11.
Biomater Res ; 27(1): 81, 2023 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-37635253

RESUMO

BACKGROUND: Exosomes are extracellular vesicles secreted by eukaryotic cells and have been extensively studied for their surface markers and internal cargo with unique functions. A deeper understanding of exosomes has allowed their application in various research areas, particularly in diagnostics and therapy. MAIN BODY: Exosomes have great potential as biomarkers and delivery vehicles for encapsulating therapeutic cargo. However, the limitations of bare exosomes, such as rapid phagocytic clearance and non-specific biodistribution after injection, pose significant challenges to their application as drug delivery systems. This review focuses on exosome-based drug delivery for treating rheumatoid arthritis, emphasizing pre/post-engineering approaches to overcome these challenges. CONCLUSION: This review will serve as an essential resource for future studies to develop novel exosome-based therapeutic approaches for rheumatoid arthritis. Overall, the review highlights the potential of exosomes as a promising therapeutic approach for rheumatoid arthritis treatment.

12.
Sci Rep ; 13(1): 12339, 2023 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-37524783

RESUMO

Transport of interstitial fluid and solutes plays a critical role in clearing metabolic waste from the brain. Transcranial application of focused ultrasound (FUS) has been shown to promote localized cerebrospinal fluid solute uptake into the brain parenchyma; however, its effects on the transport and clearance of interstitial solutes remain unknown. We demonstrate that pulsed application of low-intensity FUS to the rat brain enhances the transport of intracortically injected fluorescent tracers (ovalbumin and high molecular-weight dextran), yielding greater parenchymal tracer volume distribution compared to the unsonicated control group (ovalbumin by 40.1% and dextran by 34.6%). Furthermore, FUS promoted the drainage of injected interstitial ovalbumin to both superficial and deep cervical lymph nodes (cLNs) ipsilateral to sonication, with 78.3% higher drainage observed in the superficial cLNs compared to the non-sonicated hemisphere. The application of FUS increased the level of solute transport visible from the dorsal brain surface, with ~ 43% greater area and ~ 19% higher fluorescence intensity than the unsonicated group, especially in the pial surface ipsilateral to sonication. The sonication did not elicit tissue-level neuronal excitation, measured by an electroencephalogram, nor did it alter the molecular weight of the tracers. These findings suggest that nonthermal transcranial FUS can enhance advective transport of interstitial solutes and their subsequent removal in a completely non-invasive fashion, offering its potential non-pharmacological utility in facilitating clearance of waste from the brain.


Assuntos
Encéfalo , Dextranos , Ratos , Animais , Ratos Sprague-Dawley , Ovalbumina/metabolismo , Dextranos/metabolismo , Encéfalo/fisiologia , Sonicação
13.
PLoS One ; 18(7): e0288654, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37478086

RESUMO

The effects of transcranial focused ultrasound (FUS) stimulation of the primary somatosensory cortex and its thalamic projection (i.e., ventral posterolateral nucleus) on the generation of electroencephalographic (EEG) responses were evaluated in healthy human volunteers. Stimulation of the unilateral somatosensory circuits corresponding to the non-dominant hand generated EEG evoked potentials across all participants; however, not all perceived stimulation-mediated tactile sensations of the hand. These FUS-evoked EEG potentials (FEP) were observed from both brain hemispheres and shared similarities with somatosensory evoked potentials (SSEP) from median nerve stimulation. Use of a 0.5 ms pulse duration (PD) sonication given at 70% duty cycle, compared to the use of 1 and 2 ms PD, elicited more distinctive FEP peak features from the hemisphere ipsilateral to sonication. Although several participants reported hearing tones associated with FUS stimulation, the observed FEP were not likely to be confounded by the auditory sensation based on a separate measurement of auditory evoked potentials (AEP) to tonal stimulation (mimicking the same repetition frequency as the FUS stimulation). Off-line changes in resting-state functional connectivity (FC) associated with thalamic stimulation revealed that the FUS stimulation enhanced connectivity in a network of sensorimotor and sensory integration areas, which lasted for at least more than an hour. Clinical neurological evaluations, EEG, and neuroanatomical MRI did not reveal any adverse or unintended effects of sonication, attesting its safety. These results suggest that FUS stimulation may induce long-term neuroplasticity in humans, indicating its neurotherapeutic potential for various neurological and neuropsychiatric conditions.


Assuntos
Mãos , Sensação , Humanos , Sensação/fisiologia , Potenciais Evocados Auditivos , Potenciais Somatossensoriais Evocados/fisiologia , Sonicação/métodos , Córtex Somatossensorial/diagnóstico por imagem , Córtex Somatossensorial/fisiologia
14.
Environ Res ; 233: 116411, 2023 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-37354929

RESUMO

The growing use of plastic materials has resulted in a constant increase in the risk associated with microplastics (MPs). Ultra-violet (UV) light and wind break down modify MPs in the environment into smaller particles known as weathered MPs (WMPs) and these processes increase the risk of MP toxicity. The neurotoxicity of weathered polystyrene-MPs remains unclear. Therefore, it is important to understand the risks posed by WMPs. We evaluated the chemical changes of WMPs generated under laboratory-synchronized environmentally mimetic conditions and compared them with virgin MPs (VMPs). We found that WMP had a rough surface, slight yellow color, reduced molecular weight, and structural alteration compared with those of VMP. Next, 2 µg of ∼100 µm in size of WMP and VMP were orally administered once a day for one week to C57BL/6 male mice. Proteomic analysis revealed that the WMP group had significantly increased activation of immune and neurodegeneration-related pathways compared with that of the VMP group. Consistently, in in vitro experiments, the human brain-derived microglial cell line (HMC-3) also exhibited a more severe inflammatory response to WMP than to VMP. These results show that WMP is a more profound inflammatory factor than VMP. In summary, our findings demonstrate the toxicity of WMPs and provide theoretical insights into their potential risks to biological systems and even humans in the ecosystem.


Assuntos
Microplásticos , Poluentes Químicos da Água , Animais , Humanos , Camundongos , Masculino , Microplásticos/toxicidade , Plásticos , Poliestirenos/toxicidade , Poliestirenos/análise , Proteoma , Ecossistema , Proteômica , Camundongos Endogâmicos C57BL , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/análise , Encéfalo
15.
Sci Rep ; 13(1): 4128, 2023 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-36914775

RESUMO

The efficacy of many anti-epileptic drugs, including phenytoin (PHT), is reduced by plasma protein binding (PPB) that sequesters therapeutically active drug molecules within the bloodstream. An increase in systemic dose elevates the risk of drug side effects, which demands an alternative technique to increase the unbound concentration of PHT in a region-specific manner. We present a low-intensity focused ultrasound (FUS) technique that locally enhances the efficacy of PHT by transiently disrupting its binding to albumin. We first identified the acoustic parameters that yielded the highest PHT unbinding from albumin among evaluated parameter sets using equilibrium dialysis. Then, rats with chronic mesial temporal lobe epilepsy (mTLE) received four sessions of PHT injection, each followed by 30 min of FUS delivered to the ictal region, across 2 weeks. Two additional groups of mTLE rats underwent the same procedure, but without receiving PHT or FUS. Assessment of electrographic seizure activities revealed that FUS accompanying administration of PHT effectively reduced the number and mean duration of ictal events compared to other conditions, without damaging brain tissue or the blood-brain barrier. Our results demonstrated that the FUS technique enhanced the anti-epileptic efficacy of PHT in a chronic mTLE rodent model by region-specific PPB disruption.


Assuntos
Epilepsia do Lobo Temporal , Fenitoína , Animais , Ratos , Anticonvulsivantes/uso terapêutico , Proteínas Sanguíneas/metabolismo , Epilepsia do Lobo Temporal/induzido quimicamente , Epilepsia do Lobo Temporal/tratamento farmacológico , Fenitoína/farmacologia , Fenitoína/uso terapêutico
16.
ACS Appl Mater Interfaces ; 15(1): 2429-2436, 2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36563177

RESUMO

The surface energy of graphene and its chemical derivatives governs fundamental interfacial interactions like molecular assembly, wetting, and doping. However, quantifying the surface energy of supported two-dimensional (2D) materials, such as graphene, is difficult because (1) they are so thin that electrostatic interactions emanating from the underlying substrate are not completely screened, (2) the contribution from the monolayer is sensitive to its exact chemical state, and (3) the adsorption of airborne contaminants, as well as contaminants introduced during transfer processing, screens the electrostatic interactions from the monolayer and underlying substrate, changing the determined surface energy. Here, we determine the polar and dispersive surface energy of bare, fluorinated, and hydrogenated graphene through contact angle measurements with water and diiodomethane. We accounted for many contributing factors, including substrate surface energies and combating adsorption of airborne contaminants. Hydrogenating graphene raises its polar surface energy with little effect on its dispersive surface energy. Fluorinating graphene lowers its dispersive surface energy with a substrate-dependent effect on its polar surface energy. These results unravel how changing the chemical structure of graphene modifies its surface energy, with applications for hybrid nanomaterials, bioadhesion, biosensing, and thin-film assembly.

17.
J Gastrointest Oncol ; 14(6): 2309-2323, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-38196527

RESUMO

Background: Esophageal neuroendocrine carcinoma (ENEC) is a rare subtype of esophageal cancer (EC). It presents distinctive clinical and pathological features in comparison to esophageal squamous cell carcinoma (ESCC). To better elucidate the disparities between the two and establish a prognostic prediction model for ENEC, we conducted this study. Methods: Data of ENEC and ESCC patients (1975 to 2016) were extracted from the Surveillance, Epidemiology and End Results (SEER) database. Patients with a confirmed pathological diagnosis of ENEC and ESCC were enrolled in the study. The Chi-square test was employed to compare categorical variables, and the median survival time was analyzed using the Kaplan-Meier curve. Training and validation groups were randomly assigned at a ratio of 7:3. Factors with a significance level of <0.05 in the multifactor regression model as well as age were integrated into the nomogram model. Concordance index (C-index), calibration curves, and decision curve analyses (DCA) were generated for model validation. Results: This study encompassed a total of 737 ENEC patients and 29,420 ESCC. Compared to ESCC, ENEC patients had higher probability of liver metastasis (13.8% vs. 1.9%, P<0.001), poor differentiation (68.0% vs. 37.1%, P<0.001), and late SEER stage (52.8% vs. 26.9%, P<0.001). Patients who received either surgery, radiotherapy (RT), or chemotherapy had a significantly longer disease-specific survival (DSS) and overall survival (OS) (all P<0.001). After propensity score matching (PSM), ENEC patients were associated with shorter DSS (7.0 months vs. not reached, P<0.0001) and OS (7.0 vs. 12.0 months, P<0.0001) compared to ESCC. Race, SEER stage, surgery, RT, and chemotherapy were identified as predictors of DSS and were incorporated into the nomogram model together with age. The validation of the model using C-index (0.751 and 0.706, respectively) and calibration curves reflected the better discrimination power of the model. In addition, DCA supported the favorable potential clinical effect of the predictive model. Lastly, a risk classification based on the nomogram also verified the reliability of the model. Conclusions: ENEC and ESCC exhibit distinct clinicopathological features. Patients with ENEC experience significantly poorer survival outcomes compared to those with ESCC. Surgical intervention, radiation therapy, and chemotherapy significantly improve OS and DSS for ENEC patients. The nomogram prediction model, constructed based on age, race, stage, and treatment regimen, demonstrates accurate and effective predictive capabilities for prognostic factors in ENEC patients.

18.
PLoS One ; 17(12): e0278865, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36512563

RESUMO

Low-intensity transcranial focused ultrasound (tFUS) offers new functional neuromodulation opportunities, enabling stimulation of cortical as well as deep brain areas with high spatial resolution. Brain stimulation of awake sheep, in the absence of the confounding effects of anesthesia on brain function, provides translational insight into potential human applications with safety information supplemented by histological analyses. We examined the effects of tFUS pulsing parameters, particularly regarding pulse durations (PDs), on stimulating the cortical motor area (M1) and its thalamic projection in unanesthetized, awake sheep (n = 8). A wearable tFUS headgear, custom-made for individual sheep, enabled experiments to be conducted without using anesthesia. FUS stimuli, each 200 ms long, were delivered to the M1 and the thalamus using three different PDs (0.5, 1, and 2 ms) with the pulse repetition frequency (PRF) adjusted to maintain a 70% duty cycle at a derated in situ spatial-peak temporal-average intensity (Ispta) of 3.6 W/cm2. Efferent electromyography (EMG) responses to stimulation were quantified from both hind limbs. Group-averaged EMG responses from each of the hind limbs across the experimental conditions revealed selective responses from the hind limb contralateral to sonication. The use of 0.5 and 1 ms PDs generated higher EMG signal amplitudes compared to those obtained using a 2 ms PD. Faster efferent response was also observed from thalamic stimulation than that from stimulating the M1. Post-sonication behavioral observation and histological assessment performed 24 h and 1 month after sonication were not indicative of any abnormalities. The results suggest the presence of pulsing scheme-dependent effects of tFUS on brain stimulation and attest its safety in awake large animals.


Assuntos
Córtex Motor , Vigília , Humanos , Animais , Ovinos , Mapeamento Encefálico/métodos , Encéfalo/fisiologia , Córtex Motor/fisiologia , Frequência Cardíaca
19.
PLoS One ; 17(12): e0275079, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36490254

RESUMO

Lipid membranes in nature adapt and reconfigure to changes in composition, temperature, humidity, and mechanics. For instance, the oscillating mechanical forces on lung cells and alveoli influence membrane synthesis and structure during breathing. However, despite advances in the understanding of lipid membrane phase behavior and mechanics of tissue, there is a critical knowledge gap regarding the response of lipid membranes to micromechanical forces. Most studies of lipid membrane mechanics use supported lipid bilayer systems missing the structural complexity of pulmonary lipids in alveolar membranes comprising multi-bilayer interconnected stacks. Here, we elucidate the collective response of the major component of pulmonary lipids to strain in the form of multi-bilayer stacks supported on flexible elastomer substrates. We utilize X-ray diffraction, scanning probe microscopy, confocal microscopy, and molecular dynamics simulation to show that lipid multilayered films both in gel and fluid states evolve structurally and mechanically in response to compression at multiple length scales. Specifically, compression leads to increased disorder of lipid alkyl chains comparable to the effect of cholesterol on gel phases as a direct result of the formation of nanoscale undulations in the lipid multilayers, also inducing buckling delamination and enhancing multi-bilayer alignment. We propose this cooperative short- and long-range reconfiguration of lipid multilayered films under compression constitutes a mechanism to accommodate stress and substrate topography. Our work raises fundamental insights regarding the adaptability of complex lipid membranes to mechanical stimuli. This is critical to several technologies requiring mechanically reconfigurable surfaces such as the development of electronic devices interfacing biological materials.


Assuntos
Colesterol , Bicamadas Lipídicas , Bicamadas Lipídicas/química , Membrana Celular/química , Colesterol/química , Simulação de Dinâmica Molecular , Difração de Raios X
20.
Sensors (Basel) ; 22(19)2022 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-36236775

RESUMO

Crowdfunding has seen an enormous rise, becoming a new alternative funding source for emerging companies or new startups in recent years. As crowdfunding prevails, it is also under substantial risk of the occurrence of fraud. Though a growing number of articles indicate that crowdfunding scams are a new imminent threat to investors, little is known about them primarily due to the lack of measurement data collected from real scam cases. This paper fills the gap by collecting, labeling, and analyzing publicly available data of a hundred fraudulent campaigns on a crowdfunding platform. In order to find and understand distinguishing characteristics of crowdfunding scams, we propose to use a broad range of traits including project-based traits, project creator-based ones, and content-based ones such as linguistic cues and Named Entity Recognition features, etc. We then propose to use the feature selection method called Forward Stepwise Logistic Regression, through which 17 key discriminating features (including six original and hitherto unused ones) of scam campaigns are discovered. Based on the selected 17 key features, we present and discuss our findings and insights on distinguishing characteristics of crowdfunding scams, and build our scam detection model with 87.3% accuracy. We also explore the feasibility of early scam detection, building a model with 70.2% of classification accuracy right at the time of project launch. We discuss what features from which sections are more helpful for early scam detection on day 0 and thereafter.


Assuntos
Crowdsourcing , Crowdsourcing/métodos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...