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BackgroundAge-related fertility decay is a great challenge for clinicians. Growth hormone (GH) supplementation has been studied as an adjuvant since late 1980s. However, it has not come to a consensus on the GH administration due to the ambiguous efficacy among studies with different enrolled population and dosage regime.MethodsA self-controlled retrospective study was conducted on women with advanced maternal age who underwent at least a previous cycle without GH (GH−) and a subsequent cycle with GH co-treatment (GH+). The ovarian stimulation parameters and outcomes were compared between the two cycles and logistical analysis was applied to further explore the association between GH administration protocol as well as other clinical parameters and cumulative live birth in GH+cycle.ResultsA total of 150 women aged 35-43 were included. The number of oocytes retrieved, MII oocytes, 2PNs, transferrable embryos and good-quality embryos in GH+ significantly increased (p < 0.001). The proportion of cycles with no transferrable embryos was significantly reduced in GH+ cycle compared with previous GH− cycle (3 vs. 32; p < 0.001). GH co-treatment cycles showed significantly higher clinical pregnancy rates (43.75% vs. 6.06%; 38.35% vs. 12.04%, p < 0.001), live birth rates (29.17% vs. 0; 27.07% vs. 0, p < 0.001) in both fresh and frozen-thawed embryo transfer cycle. Cumulative live birth rate of the GH+ cycle reached 33.33%. Use of GH prior to Gn stimulation and lasting until the hCG day seemed to achieve a higher successful live birth rate (OR 2.312, 95%CI 1.074-5.163, p=0.032).ConclusionGH supplementation could ameliorate pregnancy outcome in women with advanced maternal age. Dosage regimen of long-term pretreatment prior to Gn stimulation (4 IU every other day) and 4 IU per day until hCG day may of greater efficacy compared with concurrent administration with Gn. Additionally, it’s worthy of exploring whether an individualized dosage regimen based on the IGF or IGFBP level of patient would be more reasonable and effective. More well-designed prospective trials with large sample size and fundamental experiments on the mechanism are required to testify findings above.

This article proposes a network security protection scheme for power system embedded devices based on chip-level trusted computing, gives the overall architecture of power equipment chip-level trusted computing, introduces the principle of trust chain transfer within power terminals, and proposes the method of using the on-chip SRAM inside the main control chip of power system embedded devices as the PUF to construct the trusted root. Furthermore, we propose a complete trust transfer mechanism from booting trust to the loading that trust on operating system and application, and give the corresponding program design framework and program logic. The chip-level trusted computing program designed in this article was applied in a distribution automation DTU device equipped with the FUXI chip that is developed by the China Southern Power Grid and the Sylix OS operating system. Finally, we carry out the security protection test. The validity of the designed program is verified by running malicious programs to attack the power equipment. The results show that the designed program can effectively detect and intercept illegal programs, and provide an effective solution for the security protection of power equipment in the open network environment.

The use of the conventional dual closed-loop control strategy by photovoltaic (PV) plants with grid-connected inverters may weaken the damping of a power system, which may aggravate low-frequency oscillations (LFOs). This influence will become more severe as the penetration of PV plants increases. Therefore, it is necessary to incorporate damping controls into PV plants to suppress LFOs. This paper proposed an additional compound damping control (ACDC) system that combines additional damping control (ADC) for the inverter with ADC-based dynamic power compensation control (DPCC), allowing hybrid energy storage systems (HESSs) to suppress LFOs. First, the feasibility of suppressing low-frequency oscillations in PV plants is demonstrated by the torque method and a small signal model. Then, an additional damping controller is added to the active power control link of the PV inverter to enhance the damping abilities of the system. However, given that the damping performance of PV plants with only ADC is limited by the compensated power, PV plants require devices that can rapidly compensate for the damping power. Therefore, we added the HESS to the DC bus and proposed DPCC. Finally, a three-machine nine-node system for a PV plant was modeled and simulated in the PSCAD platform. The simulation results showed that the proposed control strategy could provide effective damping for interarea oscillation.

Constraining the virtual inertia of variable-speed wind turbines within the variable frequency limit time will be the key to improving the wind power's reliability in actively supporting the system frequency. First, this paper analyzes the controllable characteristics and evaluation methods of the virtual inertia of the wind turbine. Second, it quantifies the variable frequency limit time of the grid with high-proportion wind power and considers the wind turbine speed and power margin to restrict the virtual inertia of the wind turbine during the period of frequency drop or increase to provide reliable inertia support to ensure the safety of the system frequency. On this basis, the inertia demand under the frequency safety of the system was analyzed, and the virtual inertia control strategy of the variable-speed wind turbine in the variable frequency limit time was proposed using the speed tracking performance of the wind turbine. Finally, the grid with a high-proportion wind power simulation system is built to verify that the variable- speed wind turbine can reliably satisfy the inertia demand of system frequency modulation under the proposed control strategy and significantly improve its active support performance to the power grid. [ABSTRACT FROM AUTHOR]