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Skeletal muscle is composed of multiple fascicles, which are parallel bundles of muscle fibers surrounded by connective tissues that contain blood vessels and nerves. Here, we fabricated multifascicle human skeletal muscle scaffolds that mimic the natural structure of human skeletal muscle bundles using a seven-barrel nozzle. For the core material to form the fascicle structure, human skeletal myoblasts were encapsulated in Matrigel with calcium chloride. Meanwhile, the shell that plays a role as the connective tissue, human fibroblasts and human umbilical vein endothelial cells within a mixture of porcine muscle decellularized extracellular matrix and sodium alginate at a 95:5 ratio was used. We assessed four types of extruded scaffolds monolithic-monoculture (Mo-M), monolithic-coculture (Mo-C), multifascicle-monoculture (Mu-M), and multifascicle-coculture (Mu-C) to determine the structural effect of muscle mimicking scaffold. The Mu-C scaffold outperformed other scaffolds in cell proliferation, differentiation, vascularization, mechanical properties, and functionality. In an in vivo mouse model of volumetric muscle loss, the Mu-C scaffold effectively regenerated the tibialis anterior muscle defect, demonstrating its potential for volumetric muscle transplantation. Our nozzle will be further used to produce other volumetric functional tissues, such as tendons and peripheral nerves.
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Generating functional and perfusable micro-vascular networks is an important goal for the fabrication of large and three-dimensional tissues. Up to now, the fabrication of micro-vascular networks is a complicated multitask involving several different factors such as time consuming, cells survival, micro-diameter vasculature and strict alignment. Here, we propose a technique combining multi-material extrusion and ultrasound standing wave forces to create a network structure of human umbilical vein endothelial cells within a mixture of calcium alginate and decellularized extracellular matrix. The functionality of the matured microvasculature networks was demonstrated through the enhancement of cell-cell adhesion, angiogenesis process, and perfusion tests with microparticles, FITC-dextran, and whole mouse blood. Moreover, animal experiments exhibited the implantability including that the pre-existing blood vessels of the host sprout towards the preformed vessels of the scaffold over time and the microvessels inside the implanted scaffold matured from empty tubular structures to functional blood-carrying microvessels in two weeks.
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Microvasos , Ingeniería de Tejidos , Humanos , Animales , Ratones , Células Endoteliales de la Vena Umbilical Humana , Ingeniería de Tejidos/métodos , Adhesión Celular , MorfogénesisRESUMEN
One of the most promising techniques for treating severe peripheral artery disease is the use of cellular tissue-engineered vascular grafts (TEVGs). This study proposes an inverse-gravity (IG) extrusion technique for creating long double-layered cellular TEVGs with diameters over 3 mm. A three-layered coaxial laminar hydrogel flow in an 8 mm-diameter pipe was realised simply by changing the extrusion direction of the hydrogel from being aligned with the direction of gravity to against it. This technique produced an extruded mixture of human aortic smooth muscle cells (HASMCs) and type-I collagen as a tubular structure with an inner diameter of 3.5 mm. After a 21 day maturation period, the maximal burst pressure, longitudinal breaking force, and circumferential breaking force of the HASMC TEVG were 416 mmHg, 0.69 N, and 0.89 N, respectively. The HASMC TEVG was endothelialised with human umbilical vein endothelial cells to form a tunica intima that simulated human vessels. Besides subcutaneous implantability on mice, the double-layered blood vessels showed a considerably lower adherence of platelets and red blood cells once exposed to heparinised mouse blood and were considered nonhaemolytic. The proposed IG extrusion technique can be applied in various fields requiring multilayered materials with large diameters.
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Aorta , Plaquetas , Humanos , Animales , Ratones , Prótesis Vascular , Células Endoteliales de la Vena Umbilical Humana , HidrogelesRESUMEN
Currently, neurointervention, surgery, medication, and central nervous system (CNS) stimulation are the main treatments used in CNS diseases. These approaches are used to overcome the blood brain barrier (BBB), but they have limitations that necessitate the development of targeted delivery methods. Thus, recent research has focused on spatiotemporally direct and indirect targeted delivery methods because they decrease the effect on nontarget cells, thus minimizing side effects and increasing the patient's quality of life. Methods that enable therapeutics to be directly passed through the BBB to facilitate delivery to target cells include the use of nanomedicine (nanoparticles and extracellular vesicles), and magnetic field-mediated delivery. Nanoparticles are divided into organic, inorganic types depending on their outer shell composition. Extracellular vesicles consist of apoptotic bodies, microvesicles, and exosomes. Magnetic field-mediated delivery methods include magnetic field-mediated passive/actively-assisted navigation, magnetotactic bacteria, magnetic resonance navigation, and magnetic nanobots-in developmental chronological order of when they were developed. Indirect methods increase the BBB permeability, allowing therapeutics to reach the CNS, and include chemical delivery and mechanical delivery (focused ultrasound and LASER therapy). Chemical methods (chemical permeation enhancers) include mannitol, a prevalent BBB permeabilizer, and other chemicals-bradykinin and 1-O-pentylglycerol-to resolve the limitations of mannitol. Focused ultrasound is in either high intensity or low intensity. LASER therapies includes three types: laser interstitial therapy, photodynamic therapy, and photobiomodulation therapy. The combination of direct and indirect methods is not as common as their individual use but represents an area for further research in the field. This review aims to analyze the advantages and disadvantages of these methods, describe the combined use of direct and indirect deliveries, and provide the future prospects of each targeted delivery method. We conclude that the most promising method is the nose-to-CNS delivery of hybrid nanomedicine, multiple combination of organic, inorganic nanoparticles and exosomes, via magnetic resonance navigation following preconditioning treatment with photobiomodulation therapy or focused ultrasound in low intensity as a strategy for differentiating this review from others on targeted CNS delivery; however, additional studies are needed to demonstrate the application of this approach in more complex in vivo pathways.
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In lymphedema, proinflammatory cytokine-mediated progressive cascades always occur, leading to macroscopic fibrosis. However, no methods are practically available for measuring lymphedema-induced fibrosis before its deterioration. Technically, CT can visualize fibrosis in superficial and deep locations. For standardized measurement, verification of deep learning (DL)-based recognition was performed. A cross-sectional, observational cohort trial was conducted. After narrowing window width of the absorptive values in CT images, SegNet-based semantic segmentation model of every pixel into 5 classes (air, skin, muscle/water, fat, and fibrosis) was trained (65%), validated (15%), and tested (20%). Then, 4 indices were formulated and compared with the standardized circumference difference ratio (SCDR) and bioelectrical impedance (BEI) results. In total, 2138 CT images of 27 chronic unilateral lymphedema patients were analyzed. Regarding fibrosis segmentation, the mean boundary F1 score and accuracy were 0.868 and 0.776, respectively. Among 19 subindices of the 4 indices, 73.7% were correlated with the BEI (partial correlation coefficient: 0.420-0.875), and 13.2% were correlated with the SCDR (0.406-0.460). The mean subindex of Index 2 [Formula: see text] presented the highest correlation. DL has potential applications in CT image-based lymphedema-induced fibrosis recognition. The subtraction-type formula might be the most promising estimation method.
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Aprendizaje Profundo , Linfedema , Estudios Transversales , Fibrosis , Humanos , Linfedema/diagnóstico por imagen , Linfedema/etiología , Tomografía Computarizada por Rayos X/métodosRESUMEN
Rapid construction of pre-vascular structure is highly desired for engineered thick tissue. However, angiogenesis in free-standing scaffold has been rarely reported because of limitation in growth factor (GF) supply into the scaffold. This study, for the 1st time, investigated angiogenic sprouting in free-standing two-vasculature-embedded scaffold with three different culture conditions and additional GFs. A two-core laminar flow device continuously extruded one vascular channel with human umbilical vein endothelial cells (HUVECs) and a 3 mg/ml type-1 collagen, one hollow channel, and a shell layer with 2% w/v gelatin-alginate (70:30) composite. Under the GF flowing condition, angiogenic sprouting from the HUVEC vessel had started since day 1 and gradually grew toward the hollow channel on day 10. Due to the medium flowing, the HUVECs showed elongated spindle-like morphology homogeneously. Their viability has been over 80% up to day 10. This approach could apply to vascular investigation, and drug discovery further, not only to the engineered thick tissue.
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PURPOSE: Patients who carry reduced-activity DPYD polymorphisms have increased fluoropyrimidine (FP) toxicity risk. Although pretreatment DPYD testing is recommended throughout most of Europe, it is not recommended in the United States, and adoption has been limited. The objective of this survey was to describe the current practice in the United States regarding pretreatment DPYD testing and understand the factors deterring oncologists from ordering testing. METHODS: Survey invitations were e-mailed to 325 medical oncologists practicing in the United States who are members of the SWOG Cancer Research Network Gastrointestinal Cancer, Breast Cancer, or Early Therapeutics Committees. Descriptive statistics were used to evaluate survey responses. RESULTS: Responses were collected from 59 (18.2%) US medical oncologists, of whom 98% strongly or somewhat agree that patients with dihydropyrimidine dehydrogenase (DPD) deficiency have increased toxicity risk and 96% would modify FP dosing for a patient with known DPD deficiency. However, only 32% strongly or somewhat agree that pretreatment DPYD testing is useful to inform FP treatment, 20% have ever ordered pretreatment testing, and 3% order testing for at least 10% of their FP-treated patients. The most important factors that deter oncologists from ordering testing were low prevalence of DPD deficiency (54%) and lack of clinical practice guideline recommendations (48%). CONCLUSION: Clinical adoption of pretreatment DPYD testing is extremely limited in the United States. Utilization may be substantially increased by inclusion in the oncology clinical practice guideline recommendations, coverage through health insurance, and potentially education of medical oncologists regarding available treatment modification guidelines.
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Neoplasias de la Mama , Deficiencia de Dihidropirimidina Deshidrogenasa , Oncólogos , Antimetabolitos Antineoplásicos/efectos adversos , Neoplasias de la Mama/tratamiento farmacológico , Capecitabina/efectos adversos , Deficiencia de Dihidropirimidina Deshidrogenasa/inducido químicamente , Deficiencia de Dihidropirimidina Deshidrogenasa/tratamiento farmacológico , Dihidrouracilo Deshidrogenasa (NADP)/genética , Femenino , Fluorouracilo/efectos adversos , HumanosRESUMEN
Micro-lens array, an artificial compound eye vision system, provides a wide field of view and multi-perspective view. However, it has not been adopted as a computer vision application due to its limited visible range and high optical interference. In this research, a novel fabrication method for the flexible polydimethylsiloxane micro-lens array with a polytetrafluoroethylene light screen-aperture integrated layer was established by the simple protrusion method. The integrated layer provided longer visible range by one meter while maintaining the wide field-of-view of 100 °. The resulting images were used for obtaining depth information of a target as an example and for analyzing the rectangular and hexagonal arrangements of the micro-lenses for the future applications. With the improved visual range, wide field-of-view and flexibility, the fabricated micro-lens array can be applied to the small and curved CMOS image sensors in the future.
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Biomimética/instrumentación , Técnicas Biosensibles/instrumentación , Ojo Compuesto de los Artrópodos/fisiología , Dimetilpolisiloxanos/química , Cristalino/fisiología , Politetrafluoroetileno/química , Animales , Biomimética/métodos , Diseño de Equipo , LuzRESUMEN
The natural compound eye system has many outstanding properties, such as a more compact size, wider-angle view, better capacity to detect moving objects, and higher sensitivity to light intensity, compared to that of a single-aperture vision system. Thanks to the development of micro- and nano-fabrication techniques, many artificial compound eye imaging systems have been studied and fabricated to inherit fascinating optical features of the natural compound eye. This paper provides a review of artificial compound eye imaging systems. This review begins by introducing the principle of the natural compound eye, and then, the analysis of two types of artificial compound eye systems. We equally present the applications of the artificial compound eye imaging systems. Finally, we suggest our outlooks about the artificial compound eye imaging system.
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Aim: To evaluate toxicity risk in carriers of four DPYD variants using an institutional genetic repository. Materials & methods: Of over 65,000 patients in the repository, 582 were evaluated for the primary composite end point of grade 3 or higher toxicity or treatment modification due to toxicity. Results: The primary end point was more common in DPYD variant carriers (36.5 vs 18.1%, adjusted odds ratio 2.42, 95% CI: 1.05-5.55, p = 0.04), and in patients with decreased DPD activity (≤1 vs 2) (75.6 vs 17.0%, adjusted odds ratio 16.31, 95% CI: 2.64-100.68, p = 0.003). Conclusion: Patients carrying any of the four DPYD variants are at increased risk of severe toxicity or subsequent treatment modifications, suggesting such patients may benefit from genotype-informed treatment.
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Alelos , Antimetabolitos Antineoplásicos/efectos adversos , Capecitabina/efectos adversos , Dihidrouracilo Deshidrogenasa (NADP)/genética , Fluorouracilo/efectos adversos , Variación Genética/genética , Anciano , Antimetabolitos Antineoplásicos/administración & dosificación , Capecitabina/administración & dosificación , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/diagnóstico , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/genética , Femenino , Fluorouracilo/administración & dosificación , Humanos , Masculino , Persona de Mediana Edad , Neoplasias/tratamiento farmacológico , Neoplasias/genética , Estudios Retrospectivos , Factores de Riesgo , Resultado del TratamientoRESUMEN
Deafferentation and weight offloading can increase brain and spinal motor neuron excitability, respectively. End-effector gait robots (EEGRs) can blend these effects with stereotyped movement-induced neuroplasticity. The authors aimed to evaluate the usefulness of EEGRs as a postoperative neuro-muscular rehabilitation tool. This prospective randomized controlled trial included patients who had undergone unilateral total knee arthroplasty (TKA). Patients were randomly allocated into two groups: one using a 200-step rehabilitation program in an EEGR or the other using a walker on a floor (WF) three times a day for five weekdays. The two groups were compared by electrophysiological and biomechanical methods. Since there were no more enrollments due to funding issues, interim analysis was performed. Twelve patients were assigned to the EEGR group and eight patients were assigned to the WF group. Although the muscle volume of the quadriceps and hamstring did not differ between the two groups, the normalized peak torque of the operated knee flexors (11.28 ± 16.04 Nm/kg) was improved in the EEGR group compared to that of the operated knee flexors in the WF group (4.25 ± 14.26 Nm/kg) (p = 0.04). The normalized compound motor action potentials of the vastus medialis (VM) and biceps femoris (BF) were improved in the EEGR group (p < 0.05). However, the normalized real-time peak amplitude and total, mean area under the curve of VM were decreased during rehabilitation in the EEGR group (p < 0.05). No significant differences were found between operated and non-operated knees in the EEGR group. Five-day EEGR-assisted rehabilitation induced strengthening in the knee flexors and the muscular reactivation of the BF and VM after TKA, while reducing the real-time use of the VM. This observation may suggest the feasibility of this technique: EEGR modulated the neuronal system of the patients rather than training their muscles. However, because the study was underpowered, all of the findings should be interpreted with the utmost caution.
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Artroplastia de Reemplazo de Rodilla/rehabilitación , Osteoartritis de la Rodilla/rehabilitación , Osteoartritis de la Rodilla/cirugía , Robótica/instrumentación , Anciano , Anciano de 80 o más Años , Fenómenos Biomecánicos , Terapia por Ejercicio , Femenino , Marcha , Humanos , Articulación de la Rodilla/fisiopatología , Articulación de la Rodilla/cirugía , Movimiento , Osteoartritis de la Rodilla/fisiopatología , Estudios Prospectivos , Recuperación de la Función , Robótica/métodos , Método Simple Ciego , Andadores , Soporte de Peso/fisiologíaRESUMEN
In the field of engineered organ and drug development, three-dimensional network-structured tissue has been a long-sought goal. This paper presents a direct hydrogel extrusion process exposed to an ultrasound standing wave that aligns fibroblast cells to form a network structure. The frequency-shifted (2 MHz to 4 MHz) ultrasound actuation of a 400-micrometer square-shaped glass capillary that was continuously perfused by fibroblast cells suspended in sodium alginate generated a hydrogel string, with the fibroblasts aligned in single or quadruple streams. In the transition from the one-cell stream to the four-cell streams, the aligned fibroblast cells were continuously interconnected in the form of a branch and a junction. The ultrasound-exposed fibroblast cells displayed over 95% viability up to day 10 in culture medium without any significant difference from the unexposed fibroblast cells. This acoustofluidic method will be further applied to create a vascularized network by replacing fibroblast cells with human umbilical vein endothelial cells.
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Human umbilical vein endothelial cells (HUVECs) and human aortic smooth muscle cells (HASMCs) were coaxially and continuously extruded without ultraviolet illumination using a microfluidic-based nozzle. Type I collagen (3 mg ml-1) containing HUVECs and a crosslinking reagent (100 mM CaCl2) were supplied as the core material. A mixture of 3 mg ml-1 of type I collagen (25%) and 1.8% weight volume-1 of sodium alginate (75%) was provided as the shell layer material surrounding the core material. The HUVECs were well proliferated at the core and reshaped into a monolayer formation along the axial direction of the scaffold. The HASMCs showed more than 90% cell viability in the shell layer. Fluorescent beads were passed through the inside channel of the scaffold with the HUVEC core and HASMC shell using an in-house connector. This double-layered scaffold showed higher angiogenesis in growth factor-free medium than the scaffold with only a HUVEC core. The HASMCs in the shell layer affected angiogenesis, extracellular matrix secretion, and outer diameter. The proposed technique could be applied to three-dimensional bioprinting for the production of high-volume vascularised tissue.
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Bioimpresión , Iluminación , Andamios del Tejido , Células Endoteliales de la Vena Umbilical Humana , Humanos , Impresión Tridimensional , Ingeniería de TejidosRESUMEN
Neurons communicate with other neurons in response to environmental changes. Their goal is to transmit information to their targets reliably. A burst, which consists of multiple spikes within a short time interval, plays an essential role in enhancing the reliability of information transmission through synapses. In the visual system, retinal ganglion cells (RGCs), the output neurons of the retina, show bursting activity and transmit retinal information to the lateral geniculate neuron of the thalamus. In this study, to extend our interest to the population level, the burstings of multiple RGCs were simultaneously recorded using a multi-channel recording system. As the first step in network analysis, we focused on investigating the pairwise burst correlation between two RGCs. Furthermore, to assess if the population bursting is preserved across species, we compared the synchronized bursting of RGCs between marmoset monkey (callithrix jacchus), one species of the new world monkeys and mouse (C57BL/6J strain). First, monkey RGCs showed a larger number of spikes within a burst, while the inter-spike interval, burst duration, and inter-burst interval were smaller compared with mouse RGCs. Monkey RGCs showed a strong burst synchronization between RGCs, whereas mouse RGCs showed no correlated burst firing. Monkey RGC pairs showed significantly higher burst synchrony and mutual information than mouse RGC pairs did. Comprehensively, through this study, we emphasize that two species have a different bursting activity of RGCs and different burst synchronization suggesting two species have distinctive retinal processing.
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The objective of this proof-of-concept study was to demonstrate the targeted delivery of erythropoietin (EPO) using magnetically guided magnetic nanoparticles (MNPs).MNPs consisting of a ferric-ferrous mixture (FeCl3·6H2O and FeCl2·4H2O) were prepared using a co-precipitation method. The drug delivery system (DDS) was manufactured via the spray-drying technique using a nanospray-dryer. The DDS comprised 7.5âmg sodium alginate, 150âmg MNPs, and 1000âIU EPO.Scanning electron microscopy revealed DDS particles no more than 500ânm in size. Tiny particles on the rough surfaces of the DDS particles were composed of MNPs and/or EPO, unlike the smooth surfaces of the only alginate particles. Transmission electron microscopy showed the tiny particles from 5 to 20ânm in diameter. Fourier-transform infrared spectroscopy revealed DDS peaks characteristic of MNPs as well as of alginate. Thermal gravimetric analysis presented that 50% of DDS weight was lost in a single step around 500°C. The mode size of the DDS particles was approximately 850ânm under in vivo conditions. Standard soft lithography was applied to DDS particles prepared with fluorescent beads using a microchannel fabricated to have one inlet and two outlets in a Y-shape. The fluorescent DDS particles reached only one outlet reservoir in the presence of a neodymium magnet. The neurotoxicity was evaluated by treating SH-SY5Y cells in 48-well plates (1â×â10âcells/well) with 2âµL of a solution containing sodium alginate (0.075âmg/mL), MNPs (1.5âmg/mL), or sodium alginateâ+âMNPs. A cell viability assay kit was used to identify a 93% cell viability after MNP treatment and a 94% viability after sodium alginateâ+âMNP treatment, compared with the control. As for the DDS particle neurotoxicity, a 95% cell viability was noticed after alginate-encapsulated MNPs treatment and a 93% cell viability after DDS treatment, compared with the control.The DDS-EPO construct developed here can be small under in vivo conditions enough to pass through the lung capillaries with showing the high coating efficiency. It can be guided using magnetic control without displaying significant neurotoxicity in the form of solution or particles.
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Portadores de Fármacos/farmacología , Sistemas de Liberación de Medicamentos/métodos , Eritropoyetina/farmacología , Nanopartículas de Magnetita , Materiales Biocompatibles Revestidos/farmacología , Medios de Contraste , Fármacos Hematológicos/farmacología , Humanos , Nanopartículas de Magnetita/química , Nanopartículas de Magnetita/uso terapéutico , Ensayo de Materiales , Microscopía Electrónica de Rastreo/métodos , Tamaño de la Partícula , Propiedades de Superficie , Traumatismos del Sistema Nervioso/terapiaRESUMEN
No method has yet been approved for detecting lymphedema fibrosis before its progression. This study assessed the feasibility of computed tomography-based estimation of fibrosis. This observational, cross-sectional study included patients with lymphedema affecting one limb. Three types (maximum, mean, minimum) of computed tomography reticulation indexes were digitally calculated from trans-axial images using absorptive values, and the computed tomography reticulation indexes compared with clinical scales and measurements. Of 326 patients evaluated by at least one of lymphoscintigraphy, bio-electrical impedance, and computed tomography, 24 were evaluated by all three. The mean number of computed tomography scans in these patients was 109. Sixteen patients had breast cancer, seven had gynecologic cancers, and one had primary lymphedema. Mean computed tomography reticulation index (r = 0.52, p < 0.01) and maximal computed tomography reticulation index (r = 0.45, p < 0.05) were significantly associated with time from initial limb swelling to computed tomography. Mean computed tomography reticulation index (r = 0.86, p < 0.01), minimal computed tomography reticulation index (r = 0.79, p < 0.01), and maximal computed tomography reticulation index (r = 0.68, p < 0.01) were significantly associated with International Society of Lymphedema substage. Minimal computed tomography reticulation index correlated with 1-kHz-based bio-electrical impedance ratio (r = -0.46, p < 0.05) and with standardized proximal limb circumference difference ratio (r = 0.45, p < 0.05) of both limbs. Maximal computed tomography reticulation index had a sensitivity of 0.78, specificity of 0.60, and areas under the curve of 0.66 in detecting lymphoscintigraphic stage IV. The algorithm utilizing three-dimensional computed tomography images of epifascial fibrosis may be used as a marker for lymphedema duration, limb swelling, International Society of Lymphedema substage, and interstitial lymphatic fluids of lymphedema. The current approach shows promise in providing an additional method to assist in characterizing and monitoring lymphedema patients.
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Algoritmos , Fibrosis/diagnóstico , Imagenología Tridimensional/métodos , Linfedema/complicaciones , Tomografía Computarizada por Rayos X/métodos , Estudios de Cohortes , Estudios Transversales , Impedancia Eléctrica , Estudios de Factibilidad , Femenino , Fibrosis/diagnóstico por imagen , Fibrosis/etiología , Humanos , Linfocintigrafia/métodos , Masculino , Persona de Mediana EdadRESUMEN
Over the past decade, synthesized nanomaterials, such as carbon nanotube, nanoparticle, quantum dot, and nanowire, have already made breakthroughs in various fields, including biomedical sensors. Enormous surface area-to-volume ratio of the nanomaterials increases sensitivity dramatically compared with macro-sized material. Herein we present a comprehensive review about the working principle and fabrication process of nanowire sensor. Moreover, its applications for the detection of biomarker, virus, and DNA, as well as for drug discovery, are reviewed. Recent advances including self-powering, reusability, sensitivity in high ionic strength solvent, and long-term stability are surveyed and highlighted as well. Nanowire is expected to lead significant improvement of biomedical sensor in the near future.
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Conformal growth of atomic-thick semiconductor layers on patterned substrates can boost up the performance of electronic and optoelectronic devices remarkably. However, conformal growth is a very challenging technological task, since the control of the growth processes requires utmost precision. Herein, we report on conformal growth and characterization of monolayer MoS2 on planar, microrugged, and nanorugged SiO2/Si substrates via metal-organic chemical vapor deposition. The continuous and conformal nature of monolayer MoS2 on the rugged surface was verified by high-resolution transmission electron microscopy. Strain effects were examined by photoluminescence (PL) and Raman spectroscopy. Interestingly, the photoresponsivity (â¼254.5 mA/W) of as-grown MoS2 on the nanorugged substrate was 59 times larger than that of the planar sample (4.3 mA/W) under a small applied bias of 0.1 V. This value is record high when compared with all previous MoS2-based photocurrent generation under low or zero bias. Such enhancement in the photoresponsivity arises from a large active area for light-matter interaction and local strain for PL quenching, wherein the latter effect is the key factor and unique in the conformally grown monolayer on the nanorugged surface.
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Silicon nanowires (SiNWs) have received attention in recent years due to their anomalous piezoresistive (PZR) effects. Although the PZR effects of SiNWs have been extensively researched, they are still not fully understood. Herein, we develop a new model of the PZR effects of SiNWs to characterize the PZR effects. First, the resistance of SiNW is modeled based on the surface charge density. The characteristics of SiNW, such as surface charge and effective conducting area, can be estimated by using this resistance model. Then, PZR effects are modeled based on stress concentration and piezopinch effects. Stress concentration as a function of the physical geometry of SiNWs can amplify PZR effects by an order of magnitude. The piezopinch effects can also result in increased PZR effects that are at least two times greater than that of bulk silicon. Experimental results show that the proposed model can predict the PZR effects of SiNWs accurately.
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Rational design of drug-like small-molecule ligands based on structural information of proteins remains a significant challenge in chemical biology. In particular, designs targeting protein-protein interfaces have met little success given the dynamic nature of the protein surfaces. Herein, we utilized the structure of a small-molecule ligand in complex with Toll-like receptor 8 (TLR8) as a model system due to TLR8's clinical relevance. Overactivation of TLR8 has been suggested to play a prominent role in the pathogenesis of various autoimmune diseases; however, there are still few small-molecule antagonists available, and our rational designs led to the discovery of six exceptionally potent compounds with â¼picomolar IC50 values. Two X-ray crystallographic structures validated the contacts within the binding pocket. A variety of biological evaluations in cultured cell lines, human peripheral blood mononuclear cells, and splenocytes from human TLR8-transgenic mice further demonstrated these TLR8 inhibitors' high efficacy, suggesting strong therapeutic potential against autoimmune disorders.