Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
Sensors (Basel) ; 24(12)2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38931601

RESUMO

Muscles play an indispensable role in human life. Surface electromyography (sEMG), as a non-invasive method, is crucial for monitoring muscle status. It is characterized by its real-time, portable nature and is extensively utilized in sports and rehabilitation sciences. This study proposed a wireless acquisition system based on multi-channel sEMG for objective monitoring of grip force. The system consists of an sEMG acquisition module containing four-channel discrete terminals and a host computer receiver module, using Bluetooth wireless transmission. The system is portable, wearable, low-cost, and easy to operate. Leveraging the system, an experiment for grip force prediction was designed, employing the bald eagle search (BES) algorithm to enhance the Random Forest (RF) algorithm. This approach established a grip force prediction model based on dual-channel sEMG signals. As tested, the performance of acquisition terminal proceeded as follows: the gain was up to 1125 times, and the common mode rejection ratio (CMRR) remained high in the sEMG signal band range (96.94 dB (100 Hz), 84.12 dB (500 Hz)), while the performance of the grip force prediction algorithm had an R2 of 0.9215, an MAE of 1.0637, and an MSE of 1.7479. The proposed system demonstrates excellent performance in real-time signal acquisition and grip force prediction, proving to be an effective muscle status monitoring tool for rehabilitation, training, disease condition surveillance and scientific fitness applications.


Assuntos
Algoritmos , Eletromiografia , Força da Mão , Eletromiografia/métodos , Humanos , Força da Mão/fisiologia , Masculino , Processamento de Sinais Assistido por Computador , Adulto , Dispositivos Eletrônicos Vestíveis , Músculo Esquelético/fisiologia , Monitorização Fisiológica/métodos , Monitorização Fisiológica/instrumentação , Tecnologia sem Fio/instrumentação
2.
Adv Radiat Oncol ; 8(3): 101183, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36896216

RESUMO

Purpose: Skin tattoos represent the standard approach for surface alignment and setup of breast cancer radiation therapy, yet permanent skin markings contribute to adverse cosmesis and patient dissatisfaction. With the advent of contemporary surface-imaging technology, we evaluated setup accuracy and timing between "tattoo-less" and traditional tattoo-based setup techniques. Methods and Materials: Patients receiving accelerated partial breast irradiation (APBI) underwent traditional tattoo-based setup (TTB), alternating daily with a tattoo-less setup via surface imaging using AlignRT (ART). Following initial setup, position was verified via daily kV imaging, with matching on surgical clips representing ground truth. Translational shifts (TS) and rotational shifts (RS) were ascertained, as were setup time and total in-room time. Statistical analyses used the Wilcoxon signed rank test and Pitman-Morgan variance test. Results: A total of 43 patients receiving APBI and 356 treatment fractions were analyzed (174 TTB fractions and 182 using ART). For tattoo-less setup via ART, the median absolute TS were 0.31 cm in the vertical (range, 0.08-0.82), 0.23 cm in the lateral (0.05-0.86), and 0.26 cm in the longitudinal (0.02-0.72) axes. For TTB setup, the corresponding median TS were 0.34 cm (0.05-1.98), 0.31 cm (0.09-1.84), and 0.34 cm (0.08-1.25), respectively. The median magnitude shifts were 0.59 (0.30-1.31) for ART and 0.80 (0.27-2.13) for TTB. ART was not statistically distinguishable from TTB in terms of TS, except in the longitudinal direction (P = .154, .059, and .021, respectively), and was superior to TTB for magnitude shift (P < .001). The variance of each TS variable was significantly narrower for ART compared with TTB (P ≤ .001 vertical, P = .001 lateral, P = .005 longitudinal). The median absolute RS for ART was 0.64° rotation (range, 0.00-1.90), 0.65° roll (0.05-2.90), and 0.30° pitch (0.00-1.50). The corresponding median RS for TTB were 0.80° (0.00-2.50), 0.64° (0.00-3.00), and 0.46° (0.00-2.90), respectively. ART setup was not statistically different from TTB in terms of RS (P = .868, .236, and .079, respectively). ART showed lower variance than TTB in terms of pitch (P = .009). The median total in-room time was shorter for ART than TTB (15.42 vs 17.25 minutes; P = .008), as was the median setup time (11.12 vs 13.00 minutes; P = .001). Moreover, ART had a narrower distribution of setup time with fewer lengthy outliers versus TTB. Conclusions: These findings suggest that a tattoo-less setup approach with AlignRT may be sufficiently accurate and expeditious to supplant surface tattoos for patients receiving APBI. Further analyses with larger cohorts will determine whether tattoo-based approaches can be replaced by noninvasive surface imaging.

3.
J Appl Clin Med Phys ; 23(11): e13748, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35946900

RESUMO

To define and evaluate the appropriate abdominal region of interest (ROI) as a surrogate of diaphragm positioning in deep-inspiration breath-hold (DIBH) for surface-guided radiotherapy (SGRT) of abdominal cancers using 3D optical surface imaging (OSI). Six potential abdominal ROIs were evaluated to calculate their correlations with the diaphragm position using 4DCT images of 20 abdominal patients. Twelve points of interest (POIs) were defined (six on the central soft tissue and six on the bilateral ribs) at three superior-inferior levels, and different sub-groups represented different ROIs. ROI-1 was the largest, containing all 12 POIs from the xiphoid to the umbilicus and between the lateral body midlines while ROI-2 had only eight inferior POIs, ROI-3 had six lateral POIs, and ROI-4 had four superior-lateral POIs over the ribs, ROI-5 contained six central and two most inferior-lateral POIs and ROI-6 contained six central and four inferior-lateral POIs. Internally, the right diaphragm dome was used to represent its positions in 4DCT (0% and 50% within the cycle). The Pearson correlation coefficients were calculated between the diaphragm dome and all 12 external POIs individually or grouped as six ROIs. The quality of the abdominal ROIs was evaluated as potential internal surrogates and, therefore, potential ROIs for SGRT DIBH setup. The four most inferior POIs show the highest mean correlation (r = 0.75) with diaphragmatic motion, and the correlation decreases as POIs move superiorly. The mean correlations are the highest for ROIs with little or no rib support: r = 0.67 for ROI-2, r = 0.64 for ROI-5, and r = 0.63 for ROI-6, while lower for ROIs with rib support: ROI-1 has r = 0.60, ROI-3 has r = 0.50, and ROI-4 has only r = 0.28. This study demonstrates that the rectangular/triangular soft-tissue ROI (with little rib support) is an optimal surrogate for body positioning and diaphragmatic motion, even when treating tumors under the rib cage. This evidence-based ROI definition should be utilized when treating abdominal cancers with free-breathing (FB) and/or DIBH setup.


Assuntos
Braquiterapia , Neoplasias , Humanos , Suspensão da Respiração , Planejamento da Radioterapia Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Braquiterapia/métodos , Respiração , Dosagem Radioterapêutica
4.
Front Nutr ; 9: 849811, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35369098

RESUMO

A long extraction time for traditional cold coffee brewing considerably reduces the production efficiency of this type of beverage. Herein, a new ultrasound-assisted cold brewing (UAC) method was established. The feasibility of UAC was assessed by comparison with main physicochemical characteristics, non-volatile and volatile compounds in coffee extracts produced by hot brewing and conventional static cold brewing methods. Compared to the static cold brews, the levels of total dissolved solids, total lipids, proteins, and titrated acids of UAC coffee extracts increased by 6-26%, 10-21%, 26-31%, and 12-15%, respectively. Caffeine, chlorogenic acid, and trigonelline concentrations were also determined by HPLC. Based on the volatile profiles obtained by HS-SPME-GC/MS, the aroma compounds in UAC was significantly different (p < 0.05) from hot brews but similar to static cold ones, suggesting that ultrasonication compensated for the time of the static cold brewing, thereby considerably shortening the extraction time (1 h vs. 12 h). This work demonstrated that the combination of ultrasound-assisted with cold brew could produce coffee with good flavor and increase the extraction efficiency, which may provide an option for the acceleration of the cold brew coffee process.

6.
Carbohydr Polym ; 266: 118132, 2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-34044948

RESUMO

Chitooligosaccharides (COS) are the degraded products of chitin or chitosan. COS is water-soluble, non-cytotoxic to organisms, readily absorbed through the intestine, and eliminated primarily through the kidneys. COS possess a wide range of biological activities, including immunomodulation, cholesterol-lowering, and antitumor activity. Although work on COS goes back at least forty years, several aspects remain unclear. This review narrates the recent developments in COS antitumor activities, while paying considerable attention to the impacts of physicochemical properties (such as molecular weight and degrees of deacetylation) and chemical modifications both in vitro and in vivo. COS derivatives not only improve some physicochemical properties, but also expand the range of applications in drug and gene delivery. COS (itself or as a drug carrier) can inhibit tumor cell proliferation and metastasis, which might be attributed to its ability to stimulate the immune response along with its anti-angiogenic activity. Further, an attempt has been made to report limitations and future research. The potential health benefits of COS and its derivatives against cancer may offer a new insight on their applications in food and medical fields.


Assuntos
Antineoplásicos/uso terapêutico , Quitina/análogos & derivados , Neoplasias/tratamento farmacológico , Animais , Antineoplásicos/síntese química , Antineoplásicos/farmacocinética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Quitina/farmacocinética , Quitina/uso terapêutico , Quitosana , Humanos , Metástase Neoplásica/tratamento farmacológico , Oligossacarídeos
7.
Nat Biomed Eng ; 4(7): 704-716, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32231314

RESUMO

Strategies for selectively imaging and delivering drugs to tumours typically leverage differentially upregulated surface molecules on cancer cells. Here, we show that intravenously injected carbon quantum dots, functionalized with multiple paired α-carboxyl and amino groups that bind to the large neutral amino acid transporter 1 (which is expressed in most tumours), selectively accumulate in human tumour xenografts in mice and in an orthotopic mouse model of human glioma. The functionalized quantum dots, which structurally mimic large amino acids and can be loaded with aromatic drugs through π-π stacking interactions, enabled-in the absence of detectable toxicity-near-infrared fluorescence and photoacoustic imaging of the tumours and a reduction in tumour burden after the targeted delivery of chemotherapeutics to the tumours. The versatility of functionalization and high tumour selectivity of the quantum dots make them broadly suitable for tumour-specific imaging and drug delivery.


Assuntos
Aminoácidos/química , Carbono/química , Sistemas de Liberação de Medicamentos/métodos , Pontos Quânticos/química , Nanomedicina Teranóstica/métodos , Animais , Engenharia Biomédica , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/tratamento farmacológico , Linhagem Celular Tumoral , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus
8.
J Agric Food Chem ; 67(6): 1691-1701, 2019 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-30658530

RESUMO

In recent years, various studies have confirmed the role of natural products as effective cancer prevention and treatment drugs. The present study demonstrated that chitosan oligosaccharide (COS) from shells of shrimp and crab caused an inhibitory effect on the proliferation of human renal carcinoma in vitro and in vivo. First, the in vivo biodistribution of COS was investigated by the synthesis of cyanine-7-labeled COS (COS-Cy7) following tail vein injection. The kidney was found to be a major target organ. Then, the impacts on renal carcinoma cell proliferation, apoptosis, and reactive oxygen species (ROS) production were observed in vitro, and an orthotopic xenograft tumor model was designed to evaluate the antitumor efficacy of COS in vivo. In renal carcinoma cells, COS induced G2/M phase arrest and apoptosis in a ROS-dependent fashion. COS significantly promoted mRNA expression of nuclear factor erythroid 2-related factor (Nrf2) and Nrf2 target genes, such as heme oxygenase 1, modifier subunit of glutamate cysteine ligase, and solute carrier family 7 member 11. Additionally, COS significantly upregulated the protein expression of glucose-regulated protein 78, protein RNA-like endoplasmic reticulum (ER) kinase, eukaryotic initiation factor 2α, activating transcription factor 4, C/EBP homologous protein, and cytochrome c, which justified the activation of the ER stress signaling pathway. In vivo, COS repressed tumor growth and induced apoptosis and ROS accumulation, consistent with the in vitro results. Taken together, COS repressed human renal carcinoma growth and induced apoptosis both in vitro and in vivo, mainly via ROS-dependent ER stress pathways.


Assuntos
Carcinoma de Células Renais/tratamento farmacológico , Quitosana/administração & dosagem , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Neoplasias Renais/tratamento farmacológico , Oligossacarídeos/administração & dosagem , Espécies Reativas de Oxigênio/metabolismo , Animais , Apoptose/efeitos dos fármacos , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/metabolismo , Carcinoma de Células Renais/fisiopatologia , Linhagem Celular Tumoral , Feminino , Humanos , Neoplasias Renais/genética , Neoplasias Renais/metabolismo , Neoplasias Renais/fisiopatologia , Camundongos Nus , Fator 2 Relacionado a NF-E2 , Fator de Transcrição CHOP
9.
Life Sci ; 202: 21-27, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29626528

RESUMO

Chitosan oligosaccharides (COS), hydrolyzed products of chitosan, have recently been reported to have various biological activities. Herein, the present study was undertaken to assess the ability of COS to potentiate the antitumor effect of cyclophosphamide (CTX) as well as alleviating the CTX-associated toxicities in vivo, in a residual-tumor; a model which is closer to clinical surgery. Sarcoma 180 (S180) residual-tumor mice were divided into 6 groups (n = 6); including control, CTX, COS 40 mg/kg, COS 80 mg/kg, and combination groups (CTX + COS 40, CTX + COS 80). Animals were killed 18 days post-intraperitoneal administration and the tumors were weighed. The spleens were harvested to determine lymphocytes proliferation and NK cell activities; blood cells were evaluated by flow cytometry, and the expression levels of TNF-α were measured using ELISA. Notably, the combined therapy (CTX + COS80) showed the most effective reduction of the tumor weight, the highest inhibition of tumor growth, and proliferation, when compared with control as well single CTX group. Additionally, COS was able to recover the CTX-induced decreases in the lymphocyte proliferation, splenocyte NK cell activity, TNF-α concentration, and abnormal CD4+/CD8+ T lymphocyte subset. The increase in infiltrating T cells and macrophages best explain the immunostimulatory effect of COS. Results herein highlighted the therapeutic potential of COS as adjuvant treatment during tumor chemotherapy.


Assuntos
Antineoplásicos Alquilantes/farmacologia , Quitosana/farmacologia , Ciclofosfamida/farmacologia , Oligossacarídeos/farmacologia , Sarcoma 180/tratamento farmacológico , Animais , Proliferação de Células/efeitos dos fármacos , Sinergismo Farmacológico , Feminino , Injeções Intraperitoneais , Células Matadoras Naturais/efeitos dos fármacos , Camundongos , Sarcoma 180/patologia , Baço/citologia , Baço/efeitos dos fármacos , Subpopulações de Linfócitos T/efeitos dos fármacos , Fator de Necrose Tumoral alfa/biossíntese
10.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1081-1082: 33-40, 2018 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-29501027

RESUMO

A new 3­aminophenylboronic acid-functionalized stationary phase based on silica for hydrophilic interaction liquid chromatography (HILIC) was developed and showed great HILIC characteristics on separation for chito­oligosaccharides. The material was synthesized by grafting 3­aminophenylboronic acid group to silica, and it was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), elemental analysis and thermal gravimetric analysis (TGA). Nucleobases and nucleosides were used to evaluate the retention property and to investigate retention mechanism by the models designed for description of partitioning and surface adsorption through adjusting ratio of water in the mobile phase. Parameters affecting chromatography behavior such as ionic strength, buffer pH and column temperature were also investigated. Results have indicated that the retention mechanism was a combination of partitioning and surface adsorption, and the hydrogen bond seemed to be the main force for the retention behavior. Finally, the new 3­aminophenylboronic acid-functionalized based on silica stationary phase was applied to separate chito-oligosaccharide samples with optimized mobile phase conditions and showed acceptable chromatograms.


Assuntos
Quitina/isolamento & purificação , Cromatografia Líquida/métodos , Oligossacarídeos/isolamento & purificação , Ácidos Borônicos , Quitina/análise , Quitina/química , Interações Hidrofóbicas e Hidrofílicas , Oligossacarídeos/análise , Oligossacarídeos/química , Dióxido de Silício , Termodinâmica
11.
J Food Sci ; 83(2): 535-542, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29350748

RESUMO

Chitosan oligosaccharides (COS), hydrolyzed products of chitosan, was found to display various biological activities. Herein, we assessed the immunostimulatory activity of COS both in in vitro and in vivo studies. In vitro cytotoxicity studies to murine macrophage RAW264.7 revealed that COS is safe even at the maximum tested concentration of 1000 µg/mL. It also stimulates the production of nitric oxide (NO) and tumor necrosis factor (TNF-α) and enhances the phagocytosis in COS-stimulated RAW264.7. We have shown that the COS could significantly (P < 0.05) restore the reduced immune organs indices, phagocytic index, lymphocyte proliferation, natural killer cell activity, and antioxidant enzyme activities in a cyclophosphamide-induced immunosuppressed mice model. COS can also improve the survival rate in irradiation injury mice and significantly (P < 0.05) increased the spleen indices and up-regulates the CD4+/CD8+ ratio in splenocytes. In sum, the aforementioned results suggest that COS might has the potential to be used as an immunostimulatory agent in patients with immune dysfunctions or be a model for functional food development. PRACTICAL APPLICATION: COS might has the potential to be used as an immunostimulatory agent in patients with immune dysfunctions or be a model for functional food development.


Assuntos
Quitosana/administração & dosagem , Ciclofosfamida/efeitos adversos , Fatores Imunológicos/administração & dosagem , Oligossacarídeos/administração & dosagem , Protetores contra Radiação/administração & dosagem , Animais , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Proliferação de Células/efeitos dos fármacos , Feminino , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Camundongos , Óxido Nítrico/imunologia , Óxido Nítrico Sintase Tipo II/imunologia , Oligossacarídeos/farmacologia , Fagocitose/efeitos dos fármacos , Fator de Necrose Tumoral alfa/imunologia
12.
Chem Biol Interact ; 279: 129-135, 2018 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-29155028

RESUMO

Colon cancer is the third most common cancer, and yet there is a lack of effective therapeutic method with low side effects. Chitosan oligosaccharides (COS) is derived from chitosan after chitin deacetylation, and attracts more interests due to smaller molecular weight and soluble property. Previously, COS, mainly absorbed through intestinal epithelia, has been reported to exhibit many bioactivities, especially its anti-tumor effect. Recent references pay little attention to molecular weight distribution which is crucial for understanding its biological behavior. Here, we studied reducing sugar content and degree of polymerization (DP) of COS. 86.73% reducing sugar exists in COS sample and the content of chitosan fractions with 2-6 is 85.8%. COS suppressed the growth of HCT116 cells in vitro and in vivo, and the inhibition rate of tumor weight in vivo was high up to 58.6%. Moreover, the morphology observation, flow cytometry analysis and mRNA expression were applied to study the apoptosis related mechanism. COS treatment promoted mitosis, late stage apoptosis and S cell cycle arrest in HCT116 cells, and enhanced the mRNA expression of BAK and reduce BCL-2 and BCL-xL. These findings may provide an important clue for clinical applications of COS as anti-tumor drug or pharmaceutic adjuvant in the future.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Quitosana/análogos & derivados , Neoplasias do Colo/tratamento farmacológico , Oligossacarídeos/farmacologia , Animais , Antineoplásicos/química , Quitosana/química , Quitosana/farmacologia , Relação Dose-Resposta a Droga , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HCT116 , Humanos , Camundongos , Camundongos Nus , Oligossacarídeos/química
13.
Environ Toxicol Chem ; 36(8): 1991-1997, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28106279

RESUMO

A rapid monitoring platform for sensitive voltammetric detection of thiamethoxam residues is reported in the present study. A ß-cyclodextrin-reduced graphene oxide composite was used as a reinforcing material in electrochemical determination of thiamethoxam. Compared with bare glassy carbon electrodes, the reduction peak currents of thiamethoxam at reduced graphene oxide/glassy carbon electrode and ß-cyclodextrin-reduced graphene oxide/glassy carbon electrode were increased by 70- and 124-fold, respectively. The experimental conditions influencing voltammetric determination of thiamethoxam, such as the amount of ß-cyclodextrin-reduced graphene oxide, solution pH, temperature, and accumulation time, were optimized. The reduction mechanism and binding affinity of this material is also discussed. Under optimal conditions, the reduction peak currents increased linearly between 0.5 µM and 16 µM concentration of thiamethoxam. The limit of detection was 0.27 µM on the basis of a signal-to-noise ratio of 3. When the proposed method was applied to brown rice in a recovery test, the recoveries were between 92.20% and 113.75%. The results were in good concordance with the high-performance liquid chromatography method. The proposed method therefore provides a promising and effective platform for sensitive and rapid determination of thiamethoxam. Environ Toxicol Chem 2017;36:1991-1997. © 2017 SETAC.


Assuntos
Técnicas Eletroquímicas/métodos , Monitoramento Ambiental/métodos , Grafite/química , Nitrocompostos/análise , Oxazinas/análise , Resíduos de Praguicidas/análise , Tiazóis/análise , beta-Ciclodextrinas/química , Carbono/química , Técnicas Eletroquímicas/instrumentação , Eletrodos , Monitoramento Ambiental/instrumentação , Limite de Detecção , Neonicotinoides , Oryza/química , Óxidos/química , Sensibilidade e Especificidade , Razão Sinal-Ruído , Tiametoxam
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA