Graphene Nanoplatelets/Polydimethylsiloxane Flexible Strain Sensor with Improved Sandwich Structure.

In engineering measurements, metal foil strain gauges suffer from a limited range and low sensitivity, necessitating the development of flexible sensors to fill the gap. This paper presents a flexible, high-performance piezoresistive sensor using a composite consisting of graphene nanoplatelets (GNPs) and polydimethylsiloxane (PDMS). The proposed sensor demonstrated a significantly wider range (97%) and higher gauge factor (GF) (6.3), effectively addressing the shortcomings of traditional strain gauges. The microstructure of the GNPs/PDMS composite was observed using a scanning electron microscope, and the distribution of the conductive network was analyzed. The mechanical behavior of the sensor encapsulation was analyzed, leading to the determination of the mechanisms influencing encapsulation. Experiments based on a standard equal-strength beam were conducted to investigate the influence of the base and coating dimensions of the sensor. The results indicated that reducing the base thickness and increasing the coating length both contributed to the enhancement of the sensor's performance. These findings provide valuable guidance for future development and design of flexible sensors.

Loosening Identification of Multi-Bolt Connections Based on Wavelet Transform and ResNet-50 Convolutional Neural Network.

A high-strength bolt connection is the key component of large-scale steel structures. Bolt loosening and preload loss during operation can reduce the load-carrying capacity, safety, and durability of the structures. In order to detect loosening damage in multi-bolt connections of large-scale civil engineering structures, we proposed a multi-bolt loosening identification method based on time-frequency diagrams and a convolutional neural network (CNN) using vi-bro-acoustic modulation (VAM) signals. Continuous wavelet transform was employed to obtain the time-frequency diagrams of VAM signals as the features. Afterward, the CNN model was trained to identify the multi-bolt loosening conditions from the raw time-frequency diagrams intelligently. It helps to get rid of the dependence on traditional manual selection of simplex and ineffective damage index and to eliminate the influence of operational noise of structures on the identification accuracy. A laboratory test was carried out on bolted connection specimens with four high-strength bolts of different degrees of loosening. The effects of different excitations, CNN models, and dataset sizes were investigated. We found that the ResNet-50 CNN model taking time-frequency diagrams of the hammer excited VAM signals, as the input had better performance in identifying the loosened bolts with various degrees of loosening at different positions. The results indicate that the proposed multi-bolt loosening identification method based on VAM and ResNet-50 CNN can identify bolt loosening with a reasonable accuracy, computational efficiency, and robustness.

Nickel hexacyanoferrate/carbon composite as a high-rate and long-life cathode material for aqueous hybrid energy storage.

A nickel hexacyanoferrate (NiHCF)/carbon composite is prepared to realize reduced structure vacancies and enhanced conductivity simultaneously. The resultant composite as a cathode material exhibits good capacity retentions both for rate capability (93% of that at 0.1 A g-1 for 2 A g-1) and cycle stability (94% after 900 cycles at 0.5 A g-1). This feature is also kept in an aqueous hybrid energy storage device, after coupling with rGO as the anode. After 5000 cycles at 2 A g-1, 94% of the initial capacity is preserved, exhibiting extraordinary stability at high rates.

FeFe(CN)6 Nanocubes as a Bipolar Electrode Material in Aqueous Symmetric Sodium-Ion Batteries.

Bipolar materials, which work as both the cathode and anode material in aqueous sodium-ion batteries, have advantages over aqueous electrolytes such as the low cost of sodium and high convenience of the material processing. However, the available materials are greatly limited. Herein, Prussian blue FeFe(CN)6 nanocubes were successfully synthesized by using a modified co-precipitation method. Owing to the well-separated redox reactions, fair cycling stability and rate capability of FeFe(CN)6 , it could be developed as a bipolar material in an aqueous sodium-ion battery. The as-obtained full battery exhibits good cycling stability and rate capability. It was able to deliver a capacity of 32 mA h g-1 at 20 C, 76 % of the capacity at 2 C. After 200 cycles at 2 C, 97 % of the initial capacity was maintained for this battery, which suggests good cycling stability.

Gastric cancer with large bowel obstruction as the first presentation: A case report.

Gastric adenocarcinoma with a large bowel obstruction as the first presentation of the condition is rare. The present study describes the case of a 59-year-old female who was diagnosed with a large bowel obstruction that was caused by gastric adenocarcinoma. The patient suffered from abdominal pain and had not defecated for 15 days. The patient had no significant medical history. The right epigastric region was slightly tender and active bowel sounds were identified. A computed tomography (CT) scan revealed a dilated fluid-filled colon with a thickened wall and adjacent fat infiltration. An upper gastrointestinal endoscopy revealed that the margin and gastric mucosa in the antrum were raised and thickened without evidence of ulcerative lesions. The patient underwent surgery and was administered adjuvant chemotherapy. The patient was followed-up for 18 months without recurrence of the tumor. This study demonstrates that the presentation of gastric cancer may vary.

Huaier aqueous extract inhibits colorectal cancer stem cell growth partially via downregulation of the Wnt/ß-catenin pathway.

The existence of cancer stem cells (CSCs) is central to the pathogenesis and therapy resistance of colorectal cancer. The aim of this study was to evaluate whether Huaier aqueous extract, a Chinese medicine, has efficacy against CSCs and to investigate the mechanisms of its anticancer effects. It was observed that the Huaier extract significantly inhibited the spheroid formation potential (P<0.05) and decreased the aldehyde dehydrogenase (ALDH)-positive cell population in colorectal primary cancer cells (P<0.05). Western blotting analysis and Wnt/ß-catenin reporter assays revealed that the Huaier extract downregulated the Wnt/ß-catenin self-renewal pathway. This is the first study to demonstrate that Huaier aqueous extract acts as an effective agent for eradicating colorectal CSCs and identifies the Wnt/ß-catenin pathway as its potential target, which may be a new approach for colorectal cancer therapy.

Prognostic role of CD133 expression in colorectal cancer: a meta-analysis.

BACKGROUND: CD133 has been identified as a putative cancer stem cell marker in colorectal cancer (CRC). However, the clinical and prognostic significance of CD133 in CRC remains controversial. METHODS: Publications were identified which assessed the clinical or prognostic significance of CD133 in CRC up to October 2012. A meta-analysis was performed to clarify the association between CD133 expression and clinical outcomes. RESULTS: A total of 12 studies met the inclusion criteria, and comprised 3652 cases. Analysis of these data showed that CD133 was not significantly associated with the depth of CRC invasion (odds ratio [OR] = 1.44, 95% confidence interval [CI]: 0.77-2.68, Z = 1.15, P = 0.252) or tumor differentiation (OR = 0.63, 95% CI: 0.28-1.46, Z = -1.06, P = 0.286). Also, there was no statistically significant association of CD133 with lymph node metastasis (OR = 1.16, 95% CI: 0.87-1.54, Z = 1.05, P = 0.315) or lymphatic invasion (OR = 1.08, 95% CI: 0.81-1.43, Z = 0.53, P = 0.594). However, in identified studies, overexpression of CD133 was highly correlated with reduced overall survival (relative risk [RR] = 2.14, 95% CI: 1.45-3.17, Z = 3.81, P = 0.0001). CONCLUSIONS: CD133 may play an important role in the progression of CRC, and overexpression of CD133 is closely related with poorer patient survival. If these findings are confirmed by well-designed prospective studies, CD133 may be a useful maker for clinical applications.

Novel micelle formulation of curcumin for enhancing antitumor activity and inhibiting colorectal cancer stem cells.

BACKGROUND AND METHODS: Curcumin has extraordinary anticancer properties but has limited use due to its insolubility in water and instability, which leads to low systemic bioavailability. We have developed a novel nanoparticulate formulation of curcumin encapsulated in stearic acid-g-chitosan oligosaccharide (CSO-SA) polymeric micelles to overcome these hurdles. RESULTS: The synthesized CSO-SA copolymer was able to self-assemble to form nanoscale micelles in aqueous medium. The mean diameter of the curcumin-loaded CSO-SA micelles was 114.7 nm and their mean surface potential was 18.5 mV. Curcumin-loaded CSO-SA micelles showed excellent internalization ability that increased curcumin accumulation in cancer cells. Curcumin-loaded CSO-SA micelles also had potent antiproliferative effects on primary colorectal cancer cells in vitro, resulting in about 6-fold greater inhibition compared with cells treated with a solution containing an equivalent concentration of free curcumin. Intravenous administration of curcumin-loaded CSO-SA micelles marginally suppressed tumor growth but did not increase cytotoxicity to mice, as confirmed by no change in body weight. Most importantly, curcumin-loaded CSO-SA micelles were effective for inhibiting subpopulations of CD44(+)/CD24(+) cells (putative colorectal cancer stem cell markers) both in vitro and in vivo. CONCLUSION: The present study identifies an effective and safe means of using curcumin-loaded CSO-SA micelles for cancer therapy.