A High-Performance Flexible Hydroacoustic Transducer Based on 1-3 PZT-5A/Silicone Rubber Composite.

In recent years, hydroacoustic transducers made of PZT/epoxy composites have been extensively employed in underwater detection, communication, and recognition for their high energy conversion efficiency. Despite the ease with which these transducers can be formed into complex shapes, their lack of mechanical flexibility limits their versatility across various sizes of underwater vehicles. This study introduces a novel flexible piezoelectric composite hydroacoustic transducer (FPCHT) based on a 1-3 PZT-5A/silicone rubber composite and an island-bridge flexible electrode, which can break the limitations of existing hydroacoustic transducers that do not have flexibility. The finite element method is used to optimize the structural parameters of high-performance 1-3 FPC. A large-sized (187 mm × 47 mm × 5.12 mm) FPC is fabricated using an improved cutting-filling method and packaged into the FPCHT. Compared with the planar rigid PZT/epoxy composite hydroacoustic transducer (RPCHT) of the same size, the TVR (186.5 db) of the FPCHT has increased by about 7 dB, indicating that it has better acoustic radiation performance and electroacoustic conversion efficiency. Furthermore, its electroacoustic performance exhibits excellent stability under different bending states. Therefore, the FPCHT with high electroacoustic performance is an ideal substitute for the existing RPCHT and promotes the development of hydroacoustic transducers towards flexibility and portability.

The super elongation complex (SEC) mediates phase transition of SPT5 during transcriptional pause release.

Release of promoter-proximally paused RNA Pol II into elongation is a tightly regulated and rate-limiting step in metazoan gene transcription. However, the biophysical mechanism underlying pause release remains unclear. Here, we demonstrate that the pausing and elongation regulator SPT5 undergoes phase transition during transcriptional pause release. SPT5 per se is prone to form clusters. The disordered domain in SPT5 is required for pause release and gene activation. During early elongation, the super elongation complex (SEC) induces SPT5 transition into elongation droplets. Depletion of SEC increases SPT5 pausing clusters. Furthermore, disease-associated SEC mutations impair phase properties of elongation droplets and transcription. Our study suggests that SEC-mediated SPT5 phase transition might be essential for pause release and early elongation and that aberrant phase properties could contribute to transcription abnormality in diseases.

QSER1 preserves the suppressive status of the pro-apoptotic genes to prevent apoptosis.

Activation of the pro-apoptotic genes by the p53 family is a critical step in induction of apoptosis. However, the molecular signaling underlying their suppression remains largely unknown. Here, we report a general role of QSER1 in preventing apoptosis. QSER1 is widely up-regulated in multiple cancers, and its up-regulation correlates with poor clinic outcomes. QSER1 knockdown significantly promotes apoptosis in both p53 wild type and mutant cancer cells. Interestingly, we show that QSER1 and p53 occupy distinct cis-regulatory regions in a common subset of the pro-apoptotic genes, and function antagonistically to maintain their proper expression. Furthermore, we identify a key regulatory DNA element named QSER1 binding site in PUMA (QBP). Deletion of QBP de-represses PUMA and induces apoptosis. Mechanistically, QSER1 functions together with SIN3A to suppress PUMA in a p53-dependent and -independent manner, suggesting that QSER1 inhibition might be a potential therapeutic strategy to induce apoptosis in cancers.

Design of Planar Array Transducers Based on Connected 1-3 Piezoelectric Composites.

To improve the transmission performance and preparation of a transducer array, two planar array transducers based on connected 1-3 piezoelectric composites as a matrix were designed. Each transducer contained 25 array elements with a gap of 1 mm between them. The length, width and height of each array element were 1 mm, 26 mm and 5 mm, respectively. Two kinds of array transducers were tested through finite element simulation and experiments. The array transducer prototype was fabricated based on two kinds of composite materials, and the fabrication cycle was short. Our results show that the maximum transmission voltage response of the two-phase 1-3 full array driver is up to 179 dB at 200-400 kHz and the acoustic radiation intensity can be increased by up to 22% compared with the traditional splicing transducer array. It is suitable for short-range target positioning and measurement. Moreover, in the single element mode, the beam of the three-phase 1-3 transducer has no sidelobe and a single element -3 dB beam width of up to 91°. Furthermore, the beam width of the two-phase 1-3 type is 54°, and the acoustic radiation breadth is improved by 40.6%. The three-phase 1-3 type array transducer has the characteristics of concentrated acoustic transmission energy of the whole array, and its -3 dB beam width is 3.5°. The beam width decreased by 12.5%, indicating that the three-phase 1-3 type transducer is suitable for short-range target detection and perception. The two array transducers have their own advantages in transmitting the voltage response and beam width, which must be selected on the basis of the requirements of practical applications.

Design and Properties Analysis of Novel Modified 1-3 Piezoelectric Composite.

With the increasing demand for energy exchangers in underwater acoustic equipment, a modified 1-3 piezoelectric composite material is fabricated based on three-component phases. The new material outperforms the traditional two-phase 1-3 structure. Flexible silicone rubber polymer strengthened the piezoelectric composite and the properties of modified 1-3 piezoelectric composite have been tested by method of finite element simulation and experiment, respectively. This modified material has a high electromechanical coupling coefficient; the maximum can reach 0.684 and -3 dB bandwidth is superior to the two-phase 1-3 type. At the same time, the modified phase 1-3 type structure has an excellent decoupling effect. Silicone rubber can reduce the negative coupling vibration of epoxy resin, the vibration model simplification of piezoelectric composite, and the result of the experiment and simulation has good consistency.

Suppression of the NTS-CPS1 regulatory axis by AFF1 in lung adenocarcinoma cells.

Upregulation of the neuropeptide neurotensin (NTS) in a subgroup of lung cancers has been linked to poor prognosis. However, the regulatory pathway centered on NTS in lung cancer remains unclear. Here we identified the NTS-specific enhancer in lung adenocarcinoma cells. The AF4/FMR2 (AFF) family protein AFF1 occupies the NTS enhancer and inhibits NTS transcription. Clustering analysis of lung adenocarcinoma gene expression data demonstrated that NTS expression is highly positively correlated with the expression of the oncogenic factor CPS1. Detailed analyses demonstrated that the IL6 pathway antagonizes NTS in regulating CPS1. Thus, our analyses revealed a novel NTS-centered regulatory axis, consisting of AFF1 as a master transcription suppressor and IL6 as an antagonist in lung adenocarcinoma cells.

Spherical-Omnidirectional Piezoelectric Composite Transducer for High- Frequency Underwater Acoustics.

Spherical-omnidirectional acoustic source has become a powerful tool to provide a near-ideal omnidirectional beam pattern for acoustic tests and communications. Current spherical-omnidirectional acoustic sources do not combine an omnidirectional beam pattern with a high transmitting voltage response (TVR) in the frequency range of above 200 kHz. This work presents the design, fabrication, and measurements of a high-frequency spherical-omnidirectional transducer that can provide a near-ideal omnidirectional beam pattern and a high TVR. The active element of the transducer consists of six identical square coupons with spherical curvature 1-3 piezoelectric composites operating in thickness mode. Electroacoustic responses of the fabricated transducer in water were measured. The measured resonance frequency of the transducer was 280 kHz. The maximum TVR was 161.3 dB re 1 µ Pa/V@1 m. The horizontal and vertical beamwidths of the transducer were 360° and 346°, respectively. Measurements show that the spherical piezoelectric composite transducer has a favorable spherical-omnidirectional behavior and a high TVR at high frequency. These results demonstrate that the spherical piezoelectric composite transducer is potentially a strong candidate for a high-frequency underwater acoustic source that requires an omnidirectional response.

ENL initiates multivalent phase separation of the super elongation complex (SEC) in controlling rapid transcriptional activation.

Release of paused RNA polymerase II (Pol II) requires incorporation of the positive transcription elongation factor b (P-TEFb) into the super elongation complex (SEC), thus resulting in rapid yet synchronous transcriptional activation. However, the mechanism underlying dynamic transition of P-TEFb from inactive to active state remains unclear. Here, we found that the SEC components are able to compartmentalize and concentrate P-TEFb via liquid-liquid phase separation from the soluble inactive HEXIM1 containing the P-TEFb complex. Specifically, ENL or its intrinsically disordered region is sufficient to initiate the liquid droplet formation of SEC. AFF4 functions together with ENL in fluidizing SEC droplets. SEC droplets are fast and dynamically formed upon serum exposure and required for rapid transcriptional induction. We also found that the fusion of ENL with MLL can boost SEC phase separation. In summary, our results suggest a critical role of multivalent phase separation of SEC in controlling transcriptional pause release.

Design and Fabrication of a High-Frequency Single-Directional Planar Underwater Ultrasound Transducer.

This paper describes the fabrication of 1-3 piezoelectric composites by using PZT5-A pure piezoelectric ceramics and the preparation of a high-frequency single-directional planar underwater ultrasound transducer by using the developed composites. First, three material models of the same size were designed and simulated by ANSYS finite element simulation software. Next, based on the simulation results, the 1-3 piezoelectric composites were developed. Finally, a high-frequency single-directional planar underwater ultrasound transducer was fabricated by encapsulating and gluing the 1-3 piezoelectric composites. The performance of the transducer was tested, and results showed that the device was characterized by single-mode operation in the working frequency band, a high transmitting voltage response, and single directivity.

Menstrual blood derived mesenchymal stem cells combined with Bushen Tiaochong recipe improved chemotherapy-induced premature ovarian failure in mice by inhibiting GADD45b expression in the cell cycle pathway.

BACKGROUND: To investigate the therapeutic effects of menstrual blood derived mesenchymal stem cells (MB-MSCs) combined with Bushen Tiaochong recipe (BSTCR) on epirubicin induced premature ovarian failure (POF) in mice. METHODS: Twenty-four female C57BL/6 mice of 6-8 weeks were intraperitoneally injected with epirubicin to induce POF, and then they were randomized into 4 groups of 6 mice each and treated with PBS, MB-MSCs, BSTCR, and MB-MSCs combined with BSTCR, respectively. Six mice of the same age were used as controls. Vaginal smear, TUNEL and hematoxylin-eosin staining were to observe estrous cycles, ovarian cell apoptosis and follicles. Enzyme-linked immunosorbent analysis determined serum estradiol, follicle-stimulating hormone (FSH) and anti-Müllerian hormone (AMH) levels. RT-qPCR and Western Blot analysis were to determine GADD45b, CyclinB1, CDC2 and pCDC2 expressions. RESULTS: Epirubicin treatment resulted in a decrease in the number of primordial, primary, secondary and antral follicles, an increase in the number of atretic follicles and ovarian cell apoptosis, a decrease in estradiol and AMH levels, an increase in FSH levels, and estrous cycle arrest. However, MB-MSCs combined with BSTCR rescued epirubicin induced POF through down-regulating GADD45b and pCDC2 expressions, and up-regulating CyclinB1 and CDC2 expressions. The combined treatment showed better therapeutic efficacy than BSTCR or MB-MSCs alone. CONCLUSIONS: MB-MSCs combined with BSTCR improved the ovarian function of epirubicin induced POF mice, which might be related to the inhibition of GADD45b expression and the promotion of CyclinB1 and CDC2 expressions. The combined treatment had better therapeutic efficacy than BSTCR or MB-MSCs alone.

Endometrial mesenchymal stem cells isolated from menstrual blood repaired epirubicin-induced damage to human ovarian granulosa cells by inhibiting the expression of Gadd45b in cell cycle pathway.

BACKGROUND: To explore the effect of mesenchymal stem cells isolated from menstrual blood (MB-MSCs) on epirubicin-induced damage to human ovarian granulosa cells (GCs) and its potential mechanisms. METHODS: The estradiol, progesterone, anti-Müllerian hormone, inhibin A, and inhibin B levels were determined using enzyme-linked immunosorbent assay. The proliferation of GCs was detected by Cell Counting Kit-8 assays. The cell cycle distribution was detected by propidiumiodide single staining. The apoptosis of GCs was determined using Annexin V and 7-AAD double staining. The differentially expressed genes of GCs were analyzed with Affymetrix Human Transcriptome Array 2.0 gene chip and verified with Western blot analysis. RESULTS: Epirubicin inhibited the secretion of estradiol, progesterone, anti-Müllerian hormone, inhibin A, and inhibin B and the proliferation of GCs; arrested these GCs in G2/M phase; and promoted the apoptosis of GCs. However, MB-MSCs repaired epirubicin-induced damage to GCs. Differentially expressed genes of GCs, Gadd45b, CyclinB1, and CDC2, were found by microarray and bioinformatics analysis. Western blot showed that epirubicin upregulated Gadd45b protein expression and downregulated CyclinB1 and CDC2 protein expression, while MB-MSCs downregulated Gadd45b protein expression and upregulated CyclinB1 and CDC2 protein expression. CONCLUSIONS: MB-MSCs repaired epirubicin-induced damage to GCs, which might be related to the inhibition of Gadd45b protein expression.

Research and Fabrication of High-Frequency Broadband and Omnidirectional Transmitting Transducer.

A wide-band cylindrical transducer was developed by using the wide band of the composite material and the matched matching layer for multimode coupling. Firstly, the structure size of the transducer's sensitive component was designed by using ANSYS simulation software. Secondly, the piezoelectric composite ring-shaped sensitive component was fabricated by the piezoelectric composite curved-surface forming process, and the matching layer was coated on the periphery of the ring-shaped piezoelectric composite material. Finally, it was encapsulated and the electrodes were drawn out to make a high-frequency broadband horizontal omnidirectional water acoustic transducer prototype. After testing, the working frequency range of the transducer was 230⁻380 kHz, and the maximum transmission voltage response was 168 dB in the water.