Objective To design a phased array ultrasonic focusing control system based on sinusoidal signal excitation in order to avoid the introduction of high-frequency interference components into the ultrasonic transducer and improve the electronic focusing performance of phased array ultrasound.Methods The system designed mainly used the high-speed field programmable gate array(FPGA)chip combined with the high-speed digital to analog converter(DAC)to realize synchronous output and control of multi-channel sinusoidal signals.There were 8 sinusoidal excitation emission modules based on FPGA and DAC and one sinusoidal ultrasonic excitation control module based on ZYNQ MPSoC involved in the hardware part of the system,in which the emission modules generated multi-channel sinusoidal excitations and timing control of sinusoidal signals within the module and the control module was responsible for controlling the triggering timing between each sinusoidal excitation transmitter module.The system developed had its software designed with MATLAB App Designer to improve the human-computer interaction experience.Performance verification was carried out for the system by testing the output waveform,inter-channel delay error and focused sound field of each channel.Results The system developed achieved generation and timing control of 64-channel sinusoidal ultrasound excitations,with the output channel main frequency being 0.5 MHz,amplitude within 0 and±12.5 V and the inter-channel delay errors not higher than 26.0 ns;a focused sound field with a focal spot diameter of 4.2 mm(-3 dB)at a depth of 50 mm was obtained when the system was applied to driving a 64-array phased-array transducer.Conclusion The system designed is capable of realizing ultrasonic electron focusing under sinusoidal excitation,which helps to improve the focusing resolution of non-invasive and precise deep brain stimulation techniques relying on the accuracy of ultrasonic focusing such as transcranial magneto-acoustic stimulation(TMAS)and transcranial ultrasonic stimulation(TUS).[Chinese Medical Equipment Journal,2025,46(5):14-20]

Objective To design a phased array ultrasonic focusing control system based on sinusoidal signal excitation in order to avoid the introduction of high-frequency interference components into the ultrasonic transducer and improve the electronic focusing performance of phased array ultrasound.Methods The system designed mainly used the high-speed field programmable gate array(FPGA)chip combined with the high-speed digital to analog converter(DAC)to realize synchronous output and control of multi-channel sinusoidal signals.There were 8 sinusoidal excitation emission modules based on FPGA and DAC and one sinusoidal ultrasonic excitation control module based on ZYNQ MPSoC involved in the hardware part of the system,in which the emission modules generated multi-channel sinusoidal excitations and timing control of sinusoidal signals within the module and the control module was responsible for controlling the triggering timing between each sinusoidal excitation transmitter module.The system developed had its software designed with MATLAB App Designer to improve the human-computer interaction experience.Performance verification was carried out for the system by testing the output waveform,inter-channel delay error and focused sound field of each channel.Results The system developed achieved generation and timing control of 64-channel sinusoidal ultrasound excitations,with the output channel main frequency being 0.5 MHz,amplitude within 0 and±12.5 V and the inter-channel delay errors not higher than 26.0 ns;a focused sound field with a focal spot diameter of 4.2 mm(-3 dB)at a depth of 50 mm was obtained when the system was applied to driving a 64-array phased-array transducer.Conclusion The system designed is capable of realizing ultrasonic electron focusing under sinusoidal excitation,which helps to improve the focusing resolution of non-invasive and precise deep brain stimulation techniques relying on the accuracy of ultrasonic focusing such as transcranial magneto-acoustic stimulation(TMAS)and transcranial ultrasonic stimulation(TUS).[Chinese Medical Equipment Journal,2025,46(5):14-20]

AIM: To investigate the effects of antitumor drug paclitaxel(PTX)on the proliferation, apoptosis, cell cycle, cell morphology, and related protein expression of Müller cells, and to evaluate its potential toxicity to the retina.METHODS:Müller cells were cultured in vitro and divided into two groups: control group(normal medium)and PTX group. Retinal Müller cells were treated with different concentrations of PTX(0.005, 0.05, 0.5 and 5mg/L)for varying durations(12, 24, 36, 48 and 72h). The CCK8 method was used to assess the effects of different concentrations of PTX and treatment duration on the proliferation Müller cells. Flow cytometry was employed to investigate the impact of different concentrations of PTX on Müller cells apoptosis and cell cycle arrest. Immunofluorescence was used to observe morphological changes in Müller cells. The effects of PTX on the expression of apoptosis-related proteins and aquaporins were analyzed by Western blot and qRT-PCR.RESULTS: PTX exhibits the ability to inhibit the proliferation of Müller cells when cultured in vitro. The efficacy of this inhibition was found to be dependent on both the concentration of the drug and the duration of the stimulation. Higher concentrations of the drug and longer stimulation times resulted in a weaker ability of the cells to proliferate. Additionally, PTX also induces apoptosis in Müller cells, with increased drug concentrations and longer stimulation times leading to higher apoptosis rates. Flow cytometry analysis demonstrates that PTX arrests Müller cells in the G2-M phase of the cell cycle. Moreover, there is a distinct change in cell morphology, with a shift from the typical appearance characterized by clear and slender fibrous structures to a rounder morphology, accompanied by a significant decrease in cell numbers. Further, our findings reveal that there is a transient increase in the expression of cytoinflammatory factors following drug treatment compared to the control group. However, discontinuation of drug stimulation can alleviate this heightened expression. In treated cells, the expression of the CA XIV protein is upregulated compared to the control group, while the expression of vascular endothelial growth factor(VEGF)is downregulated(P<0.05). Additionally, the levels of inflammatory factors in the PTX group are significantly higher than those in the control group(P<0.05), suggesting that PTX has the potential to disrupt the retinal barrier function.CONCLUSION: PTX affects the proliferation and apoptosis of Müller cells, with the effects dependent on stimulation duration and drug concentration. In addition, PTX blocks the Müller cell cycle at the G2-M phase and alters cell morphology, leading to a transient upregulation of inflammatory factors and affecting the integrity of the retinal barrier. These findings indicate the potential toxicity of the antitumor drug PTX to the retina.

Cerebellar Purkinje cells (PCs) exhibit two types of discharge activities: simple spike (SS) and complex spike (CS). Previous studies found that noradrenaline (NA) can inhibit CS and bidirectionally regulate SS, but the enhancement of NA on SS is overwhelmed by the strong inhibition of excitatory molecular layer interneurons. However, the mechanism underlying the effect of NA on SS discharge frequency is not clear. Therefore, in the present study, we examined the mechanism underlying the increasing effect of NA on SS firing of PC in mouse cerebellar cortex in vivo and in cerebellar slice by cell-attached and whole-cell recording technique and pharmacological methods. GABA_A receptor was blocked by 100 µmol/L picrotoxin in the whole process. In vivo results showed that NA significantly reduced the number of spikelets of spontaneous CS and enhanced the discharge frequency of SS, but did not affect the discharge frequency of CS. In vitro experiments showed that NA reduced the number of CS spikelets and after hyperpolarization potential (AHP) induced by electrical stimulation, and increased the discharge frequency of SS. NA also reduced the amplitude of excitatory postsynaptic current (EPSC) of parallel fiber (PF)-PC and significantly increased the paired-pulse ratio (PPR). Application of yohimbine, an antagonist of α2-adrenergic receptor (AR), completely eliminated the enhancing effect of NA on SS. The α2-AR agonist, UK14304, also increased the frequency of SS. The β-AR blocker, propranolol, did not affect the effects of NA on PC. These results suggest that in the absence of GABA_A receptors, NA could attenuate the synaptic transmission of climbing fiber (CF)-PC via activating α2-AR, inhibit CS activity and reduce AHP, thus enhancing the SS discharge frequency of PC. This result suggests that NA neurons of locus coeruleus can finely regulate PC signal output by regulating CF-PC synaptic transmission.
Action Potentials/physiology* ; Animals ; Cerebellar Cortex/metabolism* ; Cerebellum/metabolism* ; Mice ; Norepinephrine/pharmacology* ; Purkinje Cells/metabolism* ; Receptors, Adrenergic, alpha-2/metabolism* ; Receptors, GABA-A/metabolism*

The c-Abl nonreceptor tyrosine kinase is activated in the cellular responses to genotoxic, oxidative and other forms of stress. Using tagged forms of c-Abl, the present studies demonstrate that c-Abl forms homodimers in cells. The results show that the c-Abl N-terminal regions interact with the corresponding C-terminal regions of both partners in the dimmer. Specifically, the c-Abl SH3 domain binds to a proline-rich motif at amino acids 958-982 in the c-Abl C-terminal region. Deletion of the proline-rich motif disrupts dimmer formation. These findings provide the first evidence that c-Abl forms homodimers and indicate that homodimerization can contribute to the regulation of c-Abl activity.
Humans ; Protein Multimerization ; Proto-Oncogene Proteins c-abl ; genetics ; metabolism ; src Homology Domains