High-Strength, Freeze-Resistant, Recyclable, and Biodegradable Polyvinyl Alcohol/Glycol/Wheat Protein Complex Organohydrogel for Wearable Sensing Devices.

The application of flexible wearable sensing devices based on conductive hydrogels in human motion signal monitoring has been widely studied. However, conventional conductive hydrogels contain a large amount of water, resulting in poor mechanical properties and limiting their application in harsh environments. Here, a simple one-pot method for preparing conductive hydrogels is proposed, that is, polyvinyl alcohol (PVA), wheat protein (WP), and lithium chloride (LiCl) are dissolved in an ethylene glycol (EG)/water binary solvent. The obtained PVA/EG/WP (PEW) conductive organohydrogel has good mechanical properties, and its tensile strength and elongation at break reach 1.19 MPa and 531%, respectively, which can withstand a load of more than 6000 times its own weight without breaking. The binary solvent system composed of EG/water endows the hydrogel with good frost resistance and water retention. PEW organohydrogel as a wearable strain sensor also has good strain sensitivity (GF = 2.36), which can be used to detect the movement and physiological activity signals in different parts of the human body. In addition, PEW organohydrogels exhibit good degradability, reducing the environmental footprint of the flexible sensors after disposal. This research provides a new and viable way to prepare a new generation of environmentally friendly sensors.

Performing differential operation with a silver dendritic metasurface at visible wavelengths.

We design a reflective silver dendritic metasurface that can perform differential operation at visible wavelengths. The metasurface consists of an upper layer of silver dendritic structures, a silica spacer, and a lower layer of silver film. Simulation results show that the metasurface can realize differential operation in red, yellow, and green bands. Such a functionality is readily extended to infrared and communication wavelengths. The metasurface samples that respond to green and red bands are prepared by using the electrochemical deposition method, and their differential operation properties are proved through tests. Silver dendritic metasurfaces that can conduct the mathematical operation in visible light pave the way for realizing miniaturized, integratable all-optical information processing systems. Their differentiation functionality, which is used for real-time ultra-fast edge detection, image contrast enhancement, hidden object detection, and other practical applications, has a great development potential.

Polyvinyl alcohol/chitosan based nanocomposite organohydrogel flexible wearable strain sensors for sports monitoring and underwater communication rescue.

Hydrogel-based flexible wearable sensors have garnered significant attention in recent years. However, the use of hydrogel, a biomaterial known for its high toughness, environmental friendliness, and frost resistance, poses a considerable challenge. In this study, we propose a stepwise construction and multiple non-covalent interaction matching strategy to successfully prepare dynamically physically crosslinked multifunctional conductive hydrogels. These hydrogels self-assembled to form a rigid crosslinked network through intermolecular hydrogen bonding and metal ion coordination chelation. Furthermore, the freeze-thawing process promoted the formation of poly(vinyl alcohol) microcrystalline domains within the amorphous hydrogel network system, resulting in exceptional mechanical properties, including a tensile strength (2.09 ± 0.01 MPa) and elongation at break of 562 ± 12 %. It can lift 10,000 times its own weight. Additionally, these hydrogels exhibit excellent resistance to swelling and maintain good toughness even at temperatures as low as -60 °C. As a wearable strain sensor with remarkable sensing ability (GF = 1.46), it can be effectively utilized in water and underwater environments. Moreover, it demonstrates excellent antimicrobial properties against Escherichia coli (Gram-negative bacteria). Leveraging its impressive sensing ability, we combine signal recognition with a deep learning model by incorporating Morse code for encryption and decryption, enabling information transmission.

Regularized least-squares migration of simultaneous-source seismic data with adaptive singular spectrum analysis.

Simultaneous-source acquisition has been recognized as an economic and efficient acquisition method, but the direct imaging of the simultaneous-source data produces migration artifacts because of the interference of adjacent sources. To overcome this problem, we propose the regularized least-squares reverse time migration method (RLSRTM) using the singular spectrum analysis technique that imposes sparseness constraints on the inverted model. Additionally, the difference spectrum theory of singular values is presented so that RLSRTM can be implemented adaptively to eliminate the migration artifacts. With numerical tests on a flat layer model and a Marmousi model, we validate the superior imaging quality, efficiency and convergence of RLSRTM compared with LSRTM when dealing with simultaneous-source data, incomplete data and noisy data.

[Expression of glucose transporter-1 and insulin receptor alpha1 in osteoblast obtained from diabetic rats' mandibles].

OBJECTIVE: To explore the expression of glucose transporter (GLUT)-1 and insulin receptor (IR) alpha1 in osteoblast obtained from diabetic rats' mandibles. METHODS: The expression of GLUT-1 and IR alpha1 of diabetic and control groups were measured by reverse transcription polymerase chain reaction, Western blot and immunohistochemistry stain. RESULTS: The mRNA expressions of GLUT-1 and IR alpha1 of diabetic group were significantly higher than control group (P<0.05). The protein expressions of GLUT-1 and IR alpha1 were similar to the mRNA expressions. CONCLUSION: Osteoblasts obtained from diabetic rats' mandibles keep the adaptation changes to hyperglycemia and hypoinsulinemia, which may contribute to their dysfunction.

[Interface bond and compatibility between Mark II machining ceramic and vita VM9 veneering porcelain].

OBJECTIVE: To investigate the interface bond and thermal compatibility between Mark II machining ceramic and Vita VM9 veneering porcelain. METHODS: A bar shaped specimen (30 mm x 15 mm x 1 mm in size) of Mark II block was prepared, with 0.5 mm-deep notch (vertical to the long axis of specimen) at the middle of the bottom surface. The upper surface was veneered with 0.3 mm VM9 dentin base porcelain. Then the specimen was fractured from the notching site and the fracture surface was examined under scanning electron microscope (SEM) and electron microprobe analyzer (EMPA) with electron beam of 1 microm in diameter. Another ten specimens (30 mm x 15 mm x 1.5 mm in size) were fabricated and the temperature of thermal shock resistance were tested. RESULTS: SEM observation showed tight bond between these two materials and EMPA results showed penetration of Al element from Mark II block into veneering porcelain and Ca element from veneering porcelain into Mark II block occurred after sintering baking. The average temperature of thermal shock resistance for specimens in this study was (194.0+/-10.3) degrees C. Cracks were mainly distributed in veneering porcelain. CONCLUSION: Chemical bond exists between the Mark II machining ceramic and Vita VM9 veneering porcelain, and there is good thermal compatibility between them.

[Raman spectroscopic analysis of post-cement-root canal dentin interface].

OBJECTIVE: To examine the compositions of those adhesion modes between luting cements and canal dentin, and to evaluate the dentin-cement-post interface by Laser-Ranian spectroscopy. METHODS: Three representative luting cements (zinc phosphate, glass ionomer and resin cements), two kinds of prefabricated posts (titanium and fiber-glass), six extracted intact human maxillary anterior teeth were used canal dentin after endodontic treatment. Laser-Raman spectroscopy measure of cement, post and canal dentin before and after luting together. RESULTS: There are no evident Raman spectra change cross the ZPC/dentin interface and glass ionomer/dentin interface, while cross the resin/dentin interface and resin/glass fiber post interface can be seen special Raman spectra. CONCLUSION: Laser-Raman microspectroscopy is a useful analytical technique for evaluation interface between dentin and luting cements. Resin cement may interact with dentin and glass fiber post.

[Effects of investment materials on cast shrinkage of base metal alloys].

OBJECTIVE: To compare the influence of different investment materials, methods and crown height on the cast shrinkage of full crowns made of dental base metal alloy. METHODS: All of the 288 wax patterns were made and divided into three groups according to their crown height. In every group, wax patterns were invested in metal rings and paper rings with three types investment material and cast with base metal alloys. Then the inside diameters of castings were measured and analyzed by statistical package SPSS. RESULTS: Differences between groups invested with the three types of material were significant(P < 0.01). There were significant difference between the groups investing with metal rings and paper rings(P < 0.01). CONCLUSION: The component of investment material and invested ring can affect the cast shrinkage of dental base metal alloy apparently.

[The study of compressive strength of phosphate-bonded investment materials].

OBJECTIVE: The purpose of this study was to compare the compressive strength of phosphate-bonded investments. METHODS: The three sorts of investments were mixed according to manufacturer's recommendation before poured in the molds. After heated up to 900 degrees C, every sample was mounted on a universal experimental machine to test its compressive strength in ambient. RESULTS: Significant differences were found between the four groups(P < 0.01). CONCLUSION: From the data above it is concluded that the compressive strength of X-20 Chrome Investment mixed with the special liquid was the highest.

[The effect of different fabrication methods and luting cements on post retention].

OBJECTIVE: This study was to compare the retention of posts fabricated by different methods and cemented with various cements in order to provide a guidance for clinical choice of post fabrication methods and luting cements. METHODS: Ninety human maxillary anterior teeth were sectioned by the cementoenamel junction and post-holes were prepared. All roots were embedded in the center of plastic cylinders and paralleled with the cylinder. All samples were divided into 9 groups randomly and equally. Posts fabricated with different methods were then cemented with different luting cements. Each sample was placed into a specialized jig and mounted on a tensile testing machine with crosshead speed of 5 mm/min. Constant tensile force was applied until the post was dislodged, and the tensile force required to dislodge the cemented post was recorded. RESULTS: The mean retention force of parapost and direct post demonstrated significantly higher than that of indirect post did (P < 0.05), but there was no significant difference between parapost and direct post(P > 0.05). The mean retention of parapost cement demonstrated significantly higher than that of ZPC and HY-Bond cement did (P < 0.05), but there was no significant difference between ZPC and HY-Bond cement (P > 0.05). CONCLUSION: Different fabrication methods and luting cements significantly affect the retention of posts; and there exists an interaction between different fabricating methods and luting cements.