Summary
Nanocellulose materials are promising sustainable and environmentally friendly candidates for green and renewable energy storage applications. Herein, hierarchical Co3O4@CNC nanohybrid ...structure was fabricated in conjunction with cobalt acetate tetrahydrate and cellulose nanocrystals (CNC) as a bio‐carbon source using green ball‐milling pathway for the first time. For comparison, pristine Co3O4 nanostructure was prepared using a similar method without adding CNC. The structural and morphological characteristics of nanohybrid composites were investigated using X‐ray diffractometer (XRD), Raman, X‐ray photoelectron spectroscopy (XPS), Fourier‐transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer‐Emmett‐Teller (BET) techniques. Furthermore, the electrochemical properties of the nanohybrid composites evaluated using cyclic voltammetry (CV), Galvanostatic Charge‐Discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques. The hierarchical Co3O4@CNC nanohybrid electrode showed the highest specific capacitance of 396 F/g that of pristine Co3O4 nanostructure electrode (was 268 F/g) at a current density of 1.0 A/g for a three‐electrode assembly. The hierarchical Co3O4@CNC nanohybrid electrode showed appreciable capacitive behavior with 96% cyclic retention even after 5,000 cycles at 1.0 A/g with energy density of 12.5 Wh k−1 at a power density of 230.5 W k−1. Thus, it is suitable for improving and/or designing active electrocatalysts for enhanced supercapacitor applications.
Nanocellulose based composite materials has attracted much attention in the fabrication of supercapacitor electrodes. Green ball‐milling technique was set forth for the fabrication of hierarchical Co3O4 nano‐hybrid structures in connotation with cellulose nanocrystals (CNCs). The nano‐hybrid hierarchical electrode (Co3O4@CNC) showed excellent specific capacitance of 396 F/g than its pristine Co3O4 nanostructure electrode (268 F/g) at a current density of 1.0 A/g for three‐electrode cell assembly.
A lower-limb exoskeleton robot identifies the wearer's walking intention and assists the walking movement through mechanical force; thus, it is important to be able to identify the wearer's movement ...in real-time. Measurement of the angle of the knee and ankle can be difficult in the case of patients who cannot move the lower-limb joint properly. Therefore, in this study, the knee angle as well as the angles of the talocrural and subtalar joints of the ankle were estimated during walking by applying the neural network to two inertial measurement unit (IMU) sensors attached to the thigh and shank. First, for angle estimation, the gyroscope and accelerometer data of the IMU sensor were obtained while walking at a treadmill speed of 1 to 2.5 km/h while wearing an exoskeleton robot. The weights according to each walking speed were calculated using a neural network algorithm programmed in MATLAB software. Second, an appropriate weight was selected according to the walking speed through the IMU data, and the knee angle and the angles of the talocrural and subtalar joints of the ankle were estimated in real-time during walking through a feedforward neural network using the IMU data received in real-time. We confirmed that the angle estimation error was accurately estimated as 1.69° ± 1.43 (mean absolute error (MAE) ± standard deviation (SD)) for the knee joint, 1.29° ± 1.01 for the talocrural joint, and 0.82° ± 0.69 for the subtalar joint. Therefore, the proposed algorithm has potential for gait rehabilitation as it addresses the difficulty of estimating angles of lower extremity patients using torque and EMG sensors.
Matrix metalloproteinases (MMPs) are proteins involved in the repair and remodeling the extracellular matrix (ECM). MMP13 is essential for bone development and healing through the remodeling of type ...I collagen (COL1), the main component of the ECM in bone tissue. Mesenchymal stem cells (MSCs)-based cell therapy has been considered a promising approach for bone regeneration because of their osteogenic properties. However, the approaches using MSC to completely regenerate bone tissue have been limited. To overcome the limitation, genetic engineering of MSC could be a strategy for promoting regeneration efficacy.
We performed in vitro and in vivo experiments using MMP13-overexpressing MSCs in the presence of COL1. To examine MMP13-overexpressing MSCs in vivo, we prepared a fibrin/COL1-based hydrogel to encapsulate MSCs and subcutaneously implanted gel-encapsulated MSCs in nude mice. We found that the osteogenic marker genes, ALP and RUNX2, were upregulated in MMP13-overexpressing MSCs through p38 phosphorylation. In addition, MMP13 overexpression in MSCs stimulated the expression of integrin α3, which is up-stream receptor of p38, and substantially increased osteogenic differentiation potential of MSCs. Bone tissue formation in MMP13-overexpressing MSCs was significantly higher than that in control MSCs. Taken together, our findings demonstrate that MMP13 is not only an essential factor for bone development and bone healing but also has a pivotal role in promoting osteogenic differentiation of MSCs to induce bone formation.
MSCs Genetically engineered to overexpress MMP13, which have a powerful potential to differentiate into the osteogenic cells, might be beneficial in bone disease therapy.
Strain sensors with high sensitivity and large stretchability are of interest in various engineering fields. Here, directly printed stretchable strain sensors with great sensitivity and high ...durability was fabricated using aerodynamically focused nanomaterials (AFN) printing system. Specifically, microscale porous conductive patterns composed of silver nanoparticles (AgNPs) and multi-walled carbon nanotubes (MWCNTs) composites are printed onto polydimethylsiloxane (PDMS) for stretchable strain sensor. Printing mechanisms of AFN printing system for nanocomposites onto flexible substrates were demonstrated and experimentally validated. The printed nanocomposites strain sensor exhibits high sensitivity and wide measurable range with high mechanical stability. It shows gauge factor (GF) of 58.7, maximum strain limit of 74% and variance in peak resistance is under 5% peak during 1000 times loading-unlading life cycle evaluation test. Sensing mechanisms were analysed and explained statistically using bivariate probit models. Moreover, we also showed that sensitivity and stretchability of printed strain sensors can be controlled by regulation of AFN printing process parameter and nanocomposite composition ratio.
Atopic dermatitis (AD) is a common skin disease in childhood whose diagnosis requires expertise in dermatology. Recent studies have indicated that host genes-microbial interactions in the gut ...contribute to human diseases including AD. We sought to develop an accurate and automated pipeline for AD diagnosis based on transcriptome and microbiota data. Using these data of 161 subjects including AD patients and healthy controls, we trained a machine learning classifier to predict the risk of AD. We found that the classifier could accurately differentiate subjects with AD and healthy individuals based on the omics data with an average F1-score of 0.84. With this classifier, we also identified a set of 35 genes and 50 microbiota features that are predictive for AD. Among the selected features, we discovered at least three genes and three microorganisms directly or indirectly associated with AD. Although further replications in other cohorts are needed, our findings suggest that these genes and microbiota features may provide novel biological insights and may be developed into useful biomarkers of AD prediction.
Stretchable electronics have recently been extensively investigated for the development of highly advanced human‐interactive devices. Here, a highly stretchable and sensitive strain sensor is ...fabricated based on the composite of fragmentized graphene foam (FGF) and polydimethylsiloxane (PDMS). A graphene foam (GF) is disintegrated into 200–300 μm sized fragments while maintaining its 3D structure by using a vortex mixer, forming a percolation network of the FGFs. The strain sensor shows high sensitivity with a gauge factor of 15 to 29, which is much higher compared to the GF/PDMS strain sensor with a gauge factor of 2.2. It is attributed to the great change in the contact resistance between FGFs over the large contact area, when stretched. In addition to the high sensitivity, the FGF/PDMS strain sensor exhibits high stretchability over 70% and high durability over 10 000 stretching‐releasing cycles. When the sensor is attached to the human body, it functions as a health‐monitoring device by detecting various human motions such as the bending of elbows and fingers in addition to the pulse of radial artery. Finally, by using the FGF, PDMS, and μ‐LEDs, a stretchable touch sensor array is fabricated, thus demonstrating its potential application as an artificial skin.
A highly stretchable and sensitive strain sensor based on a composite of fragmentized graphene foam (FGF) and polydimethylsiloxane (PDMS) is fabricated in a facile process. The FGF/PDMS sensor demonstrates high stretchability up to 70% and high durability over 10 000 stretching cycles with gauge factor in the range of 15–29 depending on the maximum strain applied and the FGF content.
The blood-spinal cord barrier (BSCB) is a specialized protective barrier that regulates the movement of molecules between blood vessels and the spinal cord parenchyma. Analogous to the blood-brain ...barrier (BBB), the BSCB plays a crucial role in maintaining the homeostasis and internal environmental stability of the central nervous system (CNS). After spinal cord injury (SCI), BSCB disruption leads to inflammatory cell invasion such as neutrophils and macrophages, contributing to permanent neurological disability. In this review, we focus on the major proteins mediating the BSCB disruption or BSCB repair after SCI. This review is composed of three parts.
Section 1. SCI and the BSCB
of the review describes critical events involved in the pathophysiology of SCI and their correlation with BSCB integrity/disruption.
Section 2. Major proteins involved in BSCB disruption in SCI
focuses on the actions of matrix metalloproteinases (MMPs), tumor necrosis factor alpha (TNF-α), heme oxygenase-1 (HO-1), angiopoietins (Angs), bradykinin, nitric oxide (NO), and endothelins (ETs) in BSCB disruption and repair.
Section 3. Therapeutic approaches
discusses the major therapeutic compounds utilized to date for the prevention of BSCB disruption in animal model of SCI through modulation of several proteins.
Background
Ruminococcus gnavus (R. gnavus) are mucin‐degrading gut bacteria that play a key role in the early colonization of the gut by serving as endogenous sources of nutrients. They can also ...influence immune development. We had previously reported a lower abundance of R. gnavus in infants with atopic dermatitis (AD) compared with that in healthy subjects. However, the underlying mechanisms remain unclear. In this study, we investigated the effect of orally administered R. gnavus on antibiotic treatment‐induced gut dysbiosis (and the underlying mechanism) in a mouse model of AD.
Methods
Four‐week‐old female BALB/C mice were administered antibiotic cocktails for 2 weeks. R. gnavus was orally administered throughout the study duration. At 6 weeks of age, AD was induced by epidermal sensitization with ovalbumin. AD phenotypes and systemic and gut immune responses were investigated.
Results
Orally administered R. gnavus significantly reduced AD‐associated parameters (i.e., transepidermal water loss, clinical score, total serum immunoglobulin (Ig) E level, OVA‐specific IgE level, and skin inflammation). R. gnavus treatment also resulted in significant downregulation of T helper 2–related cytokine mRNA and upregulation of interleukin (IL)‐10 and Foxp3 in the skin. The population of CD4+FOXP3+ T cells in mesenteric‐ and skin‐draining lymph nodes and butyrate levels in the cecum increased in R. gnavus‐administered AD mice.
Conclusions
Immune modulation by orally administered R. gnavus may alleviate AD symptoms through the enhancement of regulatory T‐cell counts and short‐chain fatty acids production in AD mice.
Since around the year 2000, hundreds of people in Korea have developed humidifier disinfectant‐associated lung injury (HDLI). We collected all HD exposure‐related information from the field ...investigations into the locations in which the 1199 registered patients had used HD. Among the people who registered, 38% (1st round = 214, 2nd = 73, 3rd = 166) were confirmed as HDLI patients. Children aged under eight years old made up the highest proportion of HDLI cases (N = 279, 62%), followed by pregnant women (N = 31, 7%). One hundred thirty‐three (29%) of the confirmed HDLI patients died. Fifty‐seven percent of HDLI patients (N = 259) developed HDLI after <1 year of HD use. The number of HDLI patients who used only the Oxy Saksak HD brand was found to be 176 (39%), followed by the brands Cefu (N = 27, 6%) and Aekyung (N = 22, 5%). HD products containing only polyhexamethylene guanidine phosphate (PHMG‐P) were the most frequently used among HDLI patients (N = 234, 52%), followed by oligo (2‐(2‐ethoxy)ethoxyethyl) guanidinium (PGH) (N = 27, 6%) and a mixture of chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) (N = 26, 6%). The average PHMG‐P inhalation level estimated from the patient group classified as suffering lung injury definitely associated with HD use was 145.1 μg/m3 (N = 91, SD = 395.1 μg/m3), higher than levels estimated from both the probable and possible HDLI patient groups. In conclusion, HD exposure‐related variables, including type of HD brand and estimated inhalation HD level, were associated with the risk of HDLI.
This study reports on the fabrication of pressure/temperature/strain sensors and all‐solid‐state flexible supercapacitors using only polydimethylsiloxane coated microporous polypyrrole/graphene foam ...composite (PDMS/PPy/GF) as a common material. A dual‐mode sensor is designed with PDMS/PPy/GF, which measures pressure and temperature with the changes of current and voltage, respectively, without interference to each other. The fabricated dual‐mode sensor shows high sensitivity, fast response/recovery, and high durability during 10 000 cycles of pressure loading. The pressure is estimated using the thermoelectric voltage induced by simultaneous increase in temperature caused by a finger touch on the sensor. Additionally, a resistor‐type strain sensor fabricated using the same PDMS/PPy/GF could detect the strain up to 50%. Flexible, high performance supercapacitor used as a power supply is fabricated with electrodes of PPy/GF for its high surface area and pseudocapacitance. Furthermore, an integrated system of such fabricated multifunctional sensors and a supercapacitor on a skin‐attachable flexible substrate using liquid–metal interconnections operates well, whereas sensors are driven by the power of the supercapacitor. This study clearly demonstrates that the appropriate choice of a single functional material enables fabrication of active multifunctional sensors for pressure, temperature, and strain, as well as the supercapacitor, that could be used in wirelessly powered wearable devices.
High‐performance solid‐state supercapacitors and multifunctional sensors sensitive to pressure, temperature, and strain are fabricated using a single common active material of microporous polydimethylsiloxane coated microporous polypyrrole/graphene foam composite. Furthermore, these sensors could be wirelessly driven with the integrated supercapacitors on a single flexible and skin‐attachable substrate.
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