Hybrid quantum dot–graphene photodetectors have recently attracted substantial interest because of their remarkable performance and low power consumption. However, the performance of the device ...greatly depends on the interfacial states and photogenerated screening field. As a consequence, the sensitivity is limited and the response time is relatively slow. In order to circumvent these challenges, herein, a composite graphene and graphene quantum dot (GQD) photodetector on lead zirconate titanate (Pb(Zr0.2Ti0.8)O3) (PZT) substrates has been designed to form an ultrasensitive photodetector over a wide range of illumination power. Under 325 nm UV light illumination, the device shows sensitivity as high as 4.06 × 109 A W−1, which is 120 times higher than reported sensitivity of the same class of devices. Plant derived GQD has a broad range of absorptivity and is an excellent candidate for harvesting photons generating electron–hole pairs. Intrinsic electric field from PZT substrate separates photogenerated electron–hole pairs as well as provides the built‐in electric field that causes the holes to transfer to the underlying graphene channel. The composite structure of graphene and GQD on PZT substrate therefore produces a simple, stable, and highly sensitive photodetector over a wide range of power with short response time, which shows a way to obtain high‐performance optoelectronic devices.
The permanent polarization of piezoelectric substrate (PZT) parallel to the built‐in electric field (DPZT) in the composite graphene and graphene quantum dot photodetector device assists efficient transfer of photogenerated holes to the graphene channel thus enhancing the photoresponsivity more than 100 times with ten times faster response compared to the device on SiO2 substrate. In contrast, opposite PZT polarization in UPZT devices abates the photoresponsivity with slower response time.
Studying neuronal activity at synapses requires high spatiotemporal resolution. For high spatial resolution in vivo imaging at depth, adaptive optics (AO) is required to correct sample-induced ...aberrations. To improve temporal resolution, Bessel focus has been combined with two-photon fluorescence microscopy (2PFM) for fast volumetric imaging at subcellular lateral resolution. To achieve both high-spatial and high-temporal resolution at depth, we develop an efficient AO method that corrects the distorted wavefront of Bessel focus at the objective focal plane and recovers diffraction-limited imaging performance. Applying AO Bessel focus scanning 2PFM to volumetric imaging of zebrafish larval and mouse brains down to 500 µm depth, we demonstrate substantial improvements in the sensitivity and resolution of structural and functional measurements of synapses in vivo. This enables volumetric measurements of synaptic calcium and glutamate activity at high accuracy, including the simultaneous recording of glutamate activity of apical and basal dendritic spines in the mouse cortex.
Single crystal metal‐free halide perovskites have received great attention in recent years owing to their excellent piezoelectric and ferroelectric properties. However, the nanotoxicity and ...piezoelectricity within the nanoscale of such materials have yet been reported for the demonstration of practical applications. In this work, the observation of intrinsic piezoelectricity in metal‐free perovskite (MDABCO‐NH4I3) films using piezoresponse force microscopy (PFM) is reported. A cytotoxicity test is also performed on MDABCO‐NH4I3 to evaluate its low‐toxic nature. The as‐synthesized MDABCO‐NH4I3 is further integrated into a piezoelectric nanogenerator (PENG). The MDABCO‐NH4I3‐based PENG (MN‐PENG) exhibits optimal output voltage and current of 15.9 V and 54.5 nA, respectively. In addition, the MN‐PENG can serve as a self‐powered strain sensor for human–machine interface applications or be adopted in in vitro electrical stimulation devices. This work demonstrates a path of perovskite‐based PENG with high performance, low toxicity, and multifunctionality for future advanced wearable sensors and portable therapeutic systems.
Here, the integration of metal‐free perovskite MDABCO‐NH4I3 into a piezoelectric nanogenerator (MN‐PENG) device is demonstrated. The high‐performance, low‐toxic, and flexible MN‐PENG device shows great potential in biomechanical energy harvesting, human–machine interfaces, and electrical stimulation therapy applications.
To create a sensitive photodetector, the transparent and conductive properties of graphene and the optical and photovoltaic properties of poly(3‐hexylthiophene) (P3HT) are combined as a hybrid ...composite. Based on the inherent nature of the band alignment between graphene and P3HT, the photogenerated holes are able to transfer to the graphene layer and improve the photoresponse to be much better than the traditional layer by layer organic system. Additionally, the graphene is deposited on a piezoelectric Pb(Zr0.2Ti0.8)O3 (PZT) substrate, and the photoresponse of such composite photodetectors is found to be ten times larger than on SiO2 base. It is demonstrated that the electric field of the polarization of piezoelectric substrate helps the spatial separation of photogenerated electrons and holes and promotes the hole doping of graphene to enhance the photoconduction. A detailed investigation of graphene layers, thickness of P3HT and time evolution shows that the composite of graphene and P3HT on PZT can be used as a sensitive photodetector and has potential as an effective solar cell. Moreover, with the replacement of P3HT by a thin layer of bulk heterojunction of polymer and fullerene, the photosensitivity can be further increased by more than one order of magnitude.
The application of a piezoelectric substrate (PZT) to enhance (down polarized, D‐PZT) or decrease (up polarized, U‐PZT) the graphene‐organic semiconductor (P3HT) hybrid photodetector compared to that of a silica substrate is reported. The permanent polarization in PZT generates an electric field promoting or decreasing charge transfer behavior of the device.
Vascular endothelial growth factor (VEGF) is well recognized as an essential component of angiogenesis and the increased proliferation and migration of endothelial cells. Bone marrow-derived ...endothelial progenitor cells (EPCs) are involved in VEGF-induced vessel formation during physiological and pathological states. Soya-cerebroside, an extract from Cordyceps militaris, reduces synovial inflammation and prevents cartilage damage in an osteoarthritis model. However, the role of soya-cerebroside in VEGF-regulated EPC angiogenesis is uncertain. Records from the Oncomine database demonstrate higher levels of VEGF in cancerous tissue compared with normal tissue. This study describes VEGF-induced promotion of EPC-associated angiogenesis in vivo and how the treatment of EPCs with soya-cerebroside inhibited VEGF-facilitated migration and tube formation. The study evidence shows that the c-Src, FAK and Runx2 signalling pathways are involved in the inhibitory effects of soya-cerebroside. This novel agent may therefore be used to inhibit EPC-associated angiogenesis.
Abstract Background Epidemiological studies have shown that ambient air pollution is closely associated with increased respiratory inflammation and decreased lung function. Particulate matters (PMs) ...are major components of air pollution that damages lung cells. However, the mechanisms remain to be elucidated. This study examines the effects of PMs on intercellular adhesion molecule-1 (ICAM-1) expression and the related mechanisms in vitro and in vivo. Result The cytotoxicity, reactive oxygen species (ROS) generation, and monocyte adherence to A549 cells were more severely affected by treatment with O-PMs (organic solvent-extractable fraction of SRM1649b) than with W-PMs (water-soluble fraction of SRM1649b). We observed a significant increase in ICAM-1 expression by O-PMs, but not W-PMs. O-PMs also induced the phosphorylation of AKT, p65, and STAT3. Pretreating A549 cells with N-acetyl cysteine (NAC), an antioxidant, attenuated O-PMs-induced ROS generation, the phosphorylation of the mentioned kinases, and the expression of ICAM-1. Furthermore, an AKT inhibitor (LY294002), NF-κB inhibitor (BAY11–7082), and STAT3 inhibitor (Stattic) significantly down-regulated O-PMs-induced ICAM-1 expression as well as the adhesion of U937 cells to epithelial cells. Interleukin-6 (IL-6) was the most significantly changed cytokine in O-PMs-treated A549 cells according to the analysis of the cytokine antibody array. The IL-6 receptor inhibitor tocilizumab (TCZ) and small interfering RNA for IL-6 significantly reduced ICAM-1 secretion and expression as well as the reduction of the AKT, p65, and STAT3 phosphorylation in O-PMs-treated A549 cells. In addition, the intratracheal instillation of PMs significantly increased the levels of the ICAM-1 and IL-6 in lung tissues and plasma in WT mice, but not in IL-6 knockout mice. Pre-administration of NAC attenuated those PMs-induced adverse effects in WT mice. Furthermore, patients with chronic obstructive pulmonary disease (COPD) had higher plasma levels of ICAM-1 and IL-6 compared to healthy subjects. Conclusion These results suggest that PMs increase ICAM-1 expression in pulmonary epithelial cells in vitro and in vivo through the IL-6/AKT/STAT3/NF-κB signaling pathway.
A stretchable, flexible, and bendable random laser system capable of lasing in a wide range of spectrum will have many potential applications in next‐ generation technologies, such as ...visible‐spectrum communication, superbright solid‐state lighting, biomedical studies, fluorescence, etc. However, producing an appropriate cavity for such a wide spectral range remains a challenge owing to the rigidity of the resonator for the generation of coherent loops. 2D materials with wrinkled structures exhibit superior advantages of high stretchability and a suitable matrix for photon trapping in between the hill and valley geometries compared to their flat counterparts. Here, the intriguing functionalities of wrinkled reduced graphene oxide, single‐layer graphene, and few‐layer hexagonal boron nitride, respectively, are utilized to design highly stretchable and wearable random laser devices with ultralow threshold. Using methyl‐ammonium lead bromide perovskite nanocrystals (PNC) to illustrate the working principle, the lasing threshold is found to be ≈10 µJ cm−2, about two times less than the lowest value ever reported. In addition to PNC, it is demonstrated that the output lasing wavelength can be tuned using different active materials such as semiconductor quantum dots. Thus, this study is very useful for the future development of high‐performance wearable optoelectronic devices.
2D materials with wrinkled structures exhibit superior advantages of high stretchability, along with a suitable matrix for photon trapping in between the hill and valley geometries compared to their flat counterparts. This is the first attempt to integrate wrinkled 2D materials with a random laser system, which enables highly stretchable and wearable random laser devices with ultralow threshold to be designed.
Abstract
Background
Sarcopenia is a common skeletal muscle disorder in the elderly population. The patients with sarcopenia increased the cost of care and the risk for hospitalization. Magnesium ...deficiency might increase reactive oxygen species and protein damage. The purpose of our study was to demonstrate the relation between oral intake magnesium and sarcopenia by European Working Group on Sarcopenia in Older People (EWGSOP) 2 definition.
Methods
Our study included 2532 participants with 1310 males and 1222 females. The multiple logistic regression model was designed to test the cross-sectional protective outcome of oral intake magnesium for sarcopenia.
Results
Oral intake magnesium had a protective outcome with sarcopenia (odd ratio (OR) = 0.997, 95% CI = 0.996, 0.998,
P
< 0.001). After fully adjusted, the significance persisted with OR = 0.998 (95% CI = 0.996, 0.999,
P
< 0.001).
Conclusion
Results of the present study showed the dose dependent relationship between oral intake magnesium and sarcopenia. Sufficient oral intake magnesium might prevent patient from sarcopenia.
Negative emotional states, such as stress, anxiety, and depression, are prevalent in university students. Personality traits have been shown to be associated with a wide range of behaviors in ...students, such as academic motivation, achievement, and social well-being. The aim of this study was to investigate the association between the Big Five personality traits and negative emotion states in university students in Taiwan. A cross-sectional study was conducted on 580 university students in Taiwan. Negative emotional states were evaluated using the Depression Anxiety Stress Scale-21 (DASS-21) and the Big Five personality traits were measured using the 48-item Big Five Inventory. A hierarchical linear regression analysis was used to assess the factors associated with DASS-21 scores. Neuroticism (standardized beta std. β = 0.45,
< 0.001) and openness (std. β = 0.12,
= 0.003) were significantly associated with DASS-21 scores, while agreeableness (std. β = -0.10,
= 0.007) was significantly and inversely associated with DASS-21 scores. Personality traits could be used to identify students at risk of negative emotional states and to undertake appropriate preventive strategies.
Chemokines modulate angiogenesis and metastasis that dictate cancer development in tumor microenvironment. Osteosarcoma is the most frequent bone tumor and is characterized by a high metastatic ...potential. Chemokine CCL5 (previously called RANTES) has been reported to facilitate tumor progression and metastasis. However, the crosstalk between chemokine CCL5 and vascular endothelial growth factor (VEGF) as well as tumor angiogenesis in human osteosarcoma microenvironment has not been well explored. In this study, we found that CCL5 increased VEGF expression and production in human osteosarcoma cells. The conditioned medium (CM) from CCL5-treated osteosarcoma cells significantly induced tube formation and migration of human endothelial progenitor cells. Pretreatment of cells with CCR5 antibody or transfection with CCR5 specific siRNA blocked CCL5-induced VEGF expression and angiogenesis. CCL5/CCR5 axis demonstrably activated protein kinase Cδ (PKCδ), c-Src and hypoxia-inducible factor-1 alpha (HIF-1α) signaling cascades to induce VEGF-dependent angiogenesis. Furthermore, knockdown of CCL5 suppressed VEGF expression and attenuated osteosarcoma CM-induced angiogenesis in vitro and in vivo. CCL5 knockdown dramatically abolished tumor growth and angiogenesis in the osteosarcoma xenograft animal model. Importantly, we demonstrated that the expression of CCL5 and VEGF were correlated with tumor stage according the immunohistochemistry analysis of human osteosarcoma tissues. Taken together, our findings provide evidence that CCL5/CCR5 axis promotes VEGF-dependent tumor angiogenesis in human osteosarcoma microenvironment through PKCδ/c-Src/HIF-1α signaling pathway. CCL5 may represent a potential therapeutic target against human osteosarcoma.
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