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With the increasing integration of distributed photovoltaic (PV) generation, the distribution network has met many challenges in operation and control. Ancillary services on PV generation systems become a necessary function to enhance the distribution network operating stability and resilience. However, due to the complexity of the control framework and the outer data dependency, the time delay on the measured data may bring a significant influence on the effectiveness of the PV system ancillary service. To solve the time delay influence, in this paper, a data-driven time-delay compensation strategy via the long short-term memory (LSTM) method is proposed. The proposed compensation strategy could realize the measured data compensation caused by the communication or calculation delay to maintain the accuracy of measured data that is input into the PV system ancillary service. Besides the LSTM-based method, the data-driven time-delay compensation strategy also includes a LSTM activation control to realize the smooth activation of the compensation strategy into the PV generation system. A modified IEEE 123 bus system with multiple distributed PV generation systems integration is conducted to verify the performance of the proposed compensation strategy. The simulation results indicate that the proposed data-driven time-delay compensation strategy could significantly improve the frequency performance of the PV ancillary service. In addition, the simulation results also show that the LSTM has a strong generalization ability for delay time constant and can deal with the random time delay caused by communication and disturbances in distribution systems.

AIM:To investigate the influence of K-115 on the proliferation and migration of human Tenon's fibroblasts(HTFs)and to access the possible mechanism. Furthermore, to provide new ideas for anti-scar treatment after glaucoma surgery.METHODS: The Tenon capsule tissues were collected from patients who underwent glaucoma surgery in Hebei General Hospital from September 2018 to September 2019. Primary culture of HTFs was performed by tissue block method. The transforming growth factor-β1(TGF-β1)was used to induce HTFs activation that can mimic glaucoma filtration surgery. The cells were treated with K-115 and divided into 4 groups: the control group was treated with dimethyl sulfoxide(DMSO); TGF-β1 group was treated with 10μg/L TGF-β1 for 24h; TGF-β1 +5 K-115 group was pretreated with 5μmol/L K-115 for 2h and then treated with 10μg/L TGF-β1 for 24h; TGF-β1+10 K-115 group was pretreated with 10μmol/L K-115 for 2h and then 10μg/L TGF-β1 was added for 24h. Cell proliferation was observed by cell proliferation experiment. The migration ability of cells was detected by scratch test. The formation of autophagosomes was observed by transmission electron microscopy. Apoptosis was visualized by Hoechst 33342/PI staining.RESULTS: Cell proliferation experiment revealed that K-115 could inhibit the proliferation of HTFs induced by TGF-β1. Scratch test suggested that K-115 could inhibit the migration of HTFs induced by TGF-β1. Transmission electron microscope results showed that K-115 could enhance autophagy of HTFs induced by TGF-β1. Hoechst 33342/PI staining suggested that K-115 did not induce apoptosis.CONCLUSIONS: K-115 may regulate the proliferation and migration of HTFs induced by TGF-β1 by increasing autophagy rather than inducing apoptosis.

AIM: To investigate the changes of morphology and function of meibomian glands in patients with type 2 diabetes mellitus and its influence on the tear film. METHODS: A total of 52 patients(104 eyes)with type 2 diabetes mellitus who came to our hospital from January 2018 to January 2020 were selected. Then they were divided into non-diabetic retinopathy group(NDR group, 31 cases with 62 eyes)and diabetic retinopathy group(DR group, 21 cases with 42 eyes)according to the fundus changes. While 38 cases(76 eyes)of diabetic-free cataract patients who treated at the same time were selected as the control group. The differences of three groups were compared with the morphology and the scores of the function of lid edge and meibomian glands, the scores of fluorescence staining of cornea, break-up time(BUT)of tear film, lipid layer thickness(LLT), blink times(BT)and partial blink rate(PBR).RESULTS: The morphology and the scores of function of lid edge and meibomian glands, the scores of fluorescence staining of cornea were significantly higher than the control group, and the DR group was significantly higher than the NDR group(all P0.05). Type 2 diabetes mellitus patients with morphology abnormalities of meibomian gland have a higher incidence of abnormal tear film function.CONCLUSION: Patients with type 2 diabetes mellitus are prone to shortening and loss of meibomian glands, which is easy to cause the dysfunction of the meibomian gland and decrease the stability of the tear film. While the patients with DR, the morphology abnormalities and dysfunction of the meibomian glands are more pronounced, and the stability of the tear film is worse.

Abstract Online monitoring of gases dissolved in transformer oil is widely applied. Improving the performance of dissolved gas analysis (DGA)‐based fault diagnosis methods by exploring new features of time‐series data has become an appealing topic. In this study, a new type of correlation features between characteristic gases was extracted from time‐series data based on the maximal information coefficient (MIC), and a fuzzy inference system was established. After the introduction of the principle of the MIC and a method for calculating the MIC‐based correlation features, the dominant symptom features that can be used to classify fault types were extracted through the receiver operating characteristic curve. Then, fuzzy rules were learnt, and a fuzzy inference system was designed. In addition, to improve the feasibility of the method, the Newton interpolation method was used for adaptation to the existing sampling cycle. The diagnostic results of the test data show that the proposed method has excellent performance and outperforms some prevailing traditional rule‐based methods as well as some artificial intelligent methods. The results also show that by exploring new correlation features from time‐series data based on the MIC, the performance of DGA‐based methods can be improved.

AIM: To measure the levels of IL-8 and IL-12p70 in the aqueous humor of patients with primary acute angle-closure glaucoma(AACG)and age-related cataract(ARC), and to investigate the clinical significance.METHODS:Totally 29 eyes of 29 AACG patients, and 17 eyes of 17 ARC patients were enrolled in the study from October 2019 to December 2020. The levels of IL-8 and IL-12p70 were measured in the aqueous humor using Cytometric Beads Array. The clinical information was recorded in the same time for the correlation.RESULTS:The level of IL-8 in AACG group was statistically elevated compared with the control group(Z= -5.384, P

Source-grid-load-storage has represented an interactive characteristic in the active distribution network (ADN). Moreover, power electronic devices have been widely used for source-grid-load-storage with the rapid development of power electronics technology. In this condition, the large-scale distributed source may cause voltage quality degradation, while the application of large-scale power electronics equipment may also lead to serious harmonic distortion. Power quality has become one of the most important issues in the development of ADN. In this paper, the source-grid-load-storage interactive power quality characteristic of the ADN is analyzed. Firstly, considering the source-grid-load-storage interaction in ADN, the voltage deviation and fluctuation are analyzed and the degrees are further quantified. Then, the source-load-storage harmonic models for the power electronic components are built, which is the basis for harmonic analysis. Moreover, the decoupled harmonic power flow algorithm for ADN is proposed to analyze the system harmonic distributions. Finally, considering the location and capacity of photovoltaic and energy storage, the interaction and power quality are analyzed in the IEEE 33-bus distribution system. With the access of energy storage, more than 20% of the voltage deviation and more than 6% of the voltage fluctuation caused by photovoltaics are effectively suppressed, while the harmonic distortion may be further increased.

AIM:To investigate the characteristic changes of ocular surface and meibomian gland function after strabismus in adolescents and analyze the related influencing factors.METHODS:Retrospective study. Totally 168 cases(224 eyes)with strabismus surgery in our hospital from January 2019 to December 2019 were selected as the study objects. According to the surgical incision, all patients were divided into the limbal incision group(group A, 54 cases, 78 eyes), trans-muscular terminal-incision group(group B, 48 cases, 62 eyes), and near-fornix incision group(group C, 66 cases, 84 eyes). Based on the number of muscles involved in the operation, patients were divided into single extraocular muscle group(68 eyes), the double extraocular muscle group(106 eyes)and three extraocular muscle group(50 eyes). The children's eye surface health were evaluated. Other eye index such as lipidlayer thickness(LLT), tear meniscus height(TMH), corneal fluorescence staining score(CFSS), tear film break up time(TBUT), tear secretion(SⅠt), and meibomial gland opening were analyzed by Lipiview eye surface interferometer.RESULTS:The eye surface and meibomian gland function presented no significant difference in groups after surgery 1wk. Postoperative 1mo, ocular surface and muscle operating meibomian gland function were improved significantly(P

Colorectal cancer (CRC) is a commonly diagnosed cancer with poor prognosis and high mortality rate. Hyperthermia (HT) is an adjunctive therapy to enhance the antitumor effects of traditional chemo- or radio- therapy. Here, we report that a cluster of essential regulator genes and speed-limit enzymes of glucose metabolism were significantly elevated under HT from a glucose metabolism PCR array analysis. Under low glucose supply or glucose metabolism inhibition, CRC cells displayed increased sensitivity to HT treatments. By transcript sequencing from the established HT resistant (HTR) colon cancer cell line LoVo HTR, we observed that IGF2BP1, an RNA-binding protein, was significantly upregulated in HTR cells compared with parental cells. Furthermore, LDHA mRNA was identified as an IGF2BP1 direct target. An RNA immunoprecipitation assay and RNA pull-down assay consistently illustrated IGF2BP1 specifically bonds to the 3′ UTR of LDHA mRNA, leading to enhanced stability of LDHA mRNA. Finally, we demonstrated that inhibiting the IGF2BP1-promoted glycolysis sensitized colon cancer cells to HT treatment via both in vitro and in vivo experiments. Our findings suggest that targeting the IGF2BP1-LDHA-glycolysis pathway might be a promising therapeutic approach to enhance the anti-cancer effects of HT treatment.

This study presents a strategy to reduce the capacitance of the submodule (SM) capacitor of a modular multilevel converter-based medium-voltage wind power converter. The design of the SM capacitor of the modular multilevel converter (MMC) should consider the actual operating conditions, especially the influence of wind speed, because wind speed will affect the voltage ripple and voltage amplitude of the SM capacitor. In the traditional method, the capacitance design of the SM capacitor will be based on relatively high wind speed and leave a certain safety margin. However, in most cases, the system operates at the highest-frequency wind speed (HFWS). For the MMC-based wind energy conversion system, a constant capacitor voltage ripple (CCVR) control method is proposed. Using this method, the SM capacitor voltage ripple can be significantly reduced by injecting the second harmonic component of circulating current. In this way, the SM capacitor with smaller capacitance can be used. Finally, the effectiveness of the proposed method is validated in RT-Lab Platform.

Industrial sector is of great significance for the economic growth of every country. The energy crisis in Pakistan has become the prime stumbling block in the economic development of the country. There are many industrial processes that need uninterrupted supply; even a trivial outage can cost millions of dollars. The main cause of "load shedding" in Pakistan is that it produces a major portion of its energy from fossil fuels, whose price and demand is constantly increasing. Most of the customers at industrial and commercial level use Diesel Generator (DiG) as a reliable alternative source of electrical power when grid supply is unavailable. The use of DiG during loading shedding hours would increase the Cost of Energy (COE) per kWh and also enhance environmental emissions. Pakistan has a wide range of renewable power sources like bioenergy, wind, solar, hydel, geothermal etc. The distinct emphasis on the implementation of an industrial microgrid in Faisalabad, Pakistan has been specified in this paper. The prospective benefits of the microgrid fall into three major kinds: cost reduction, fuel saving, and improved environmental emissions. The optimized objective of this work is to maximize these benefits. Moreover while designing the hybrid microgrid system it encounters many design challenges like sizing of the components, system feasibility, COE, system reliability etc. This study contributes to the ongoing studies about hybrid microgrid system and draws attention to the optimal design and sizing considering several techno-economic factors including Net Present Cost (NPC), COE, supply reliability, capacity shortage constraint, battery state of charge (SOC), dispatch strategy, PV power generation and PV array tracking systems. Different cases are studied; microgrid sizing, techno-economic exploration, sensitivity analysis and environmental effects are addressed using (Hybrid Optimization Model for Electric Renewables) HOMER. The results show that COE and environmental emissions have been significantly reduced for the proposed system.

With the high proportional renewable energy integration and rapid increase in the DC loads, such as the electric vehicle and distributed energy storage, the DC distribution system becomes a prospective solution for the urban power grid enhancement for its high-efficiency and eco-friendly nature. In most DC distribution systems, power interfaces are applied to connect low-voltage DC (LVDC) distribution systems with multiple medium-voltage (MV) systems in order to improve the operating reliability and economy. Compared to other types of multiports power interfaces, the three-port-isolated modular multilevel converter (I-M2C) has shown many advantages, including low cost, high power density, and low control complexity. However, the I-M2C cannot handle the power imbalance at the bipolar LVDC port like the other MMC-based three-port power interfaces, which limits the operating range and decreases the stability of the I-M2C in bipolar LVDC application. In order to solve the bipolar imbalance problems, a novel balance control method is proposed in this article. The proposed balance control method is based on symmetrical decomposition. By decoupling the MV power control and the LV bipolar power compensation control, the proposed method can eliminate the bipolar voltage deviation under different working conditions. The simulation results prove the validity and good control performance of the proposed method.

AIM: To compare the efficacy of povidone iodine with different concentration and exposure time in preparation for cataract surgery. The effect of PI on reducing the conjunctival bacterial load before cataract surgery was observed. The effect of PI on the ocular surface was also valued. In order to provide a theoretical support for clinical standardization of PI, the optimum concentration and irrigation time of PI were screened. METHODS: From June 2015 to June 2017 cataract surgery was performed in 270 cases 270 eyes. According to the concentration(0.5%, 0.1%, 0.05%)of the PI the patients were randomly divided into three groups(A, B, C,). Group A was randomly divided into three subgroups(A1, A2, A3)respectively according to different irrigation time: 30s, 1min and 2min. group B and group C were divided to subgroups similar to group A. In all groups, the conjunctiva was flush irrigate with 3ML of PI of the respective concentration. Conjunctival specimens were obtained before PI irrigation and after PI irrigation. The change of conjunctival sac bacterial flora and bacterial culture positive rate were studied. Tear break up time(BUT), cornea fluorescein staining(CFS)were evaluated 3d preoperative and 1d, 3d, 1wk, 1mo, 3mo postoperative. RESULTS:(1)The change of conjunctival sac bacterial flora. A total of 12 species of conjunctival sac bacteria were cultured before PI irrigation including 9 Gram positive bacteria and 3 Gram negative bacteria. A total of 4 species of conjunctival sac bacteria were cultured after PI irrigation including 2 Gram positive bacteria and 2 Gram negative bacteria.(2)Comparison of the positive rate of bacterial culture in conjunctival sac. Positive conjunctival sac culture for 15 eyes before PI irrigation, 5 eyes show positive after washing, the amount of positive bacteria culture was lower(PCONCLUSION: 0.5g/L PI with 30s irrigation time may effectively reduce the conjunctival sac bacteria. Compared with other groups, its damage to the eye surface is smaller. It is safe and effective in preparation for cataract surgery.

Modular multilevel converter (MMC) has been widely concerned due to its inherent excellent performance in recent years. However, in practical engineering, one of the technical challenges of MMC operation control is how to complete the submodule (SM) capacitors precharging safely and effectively, and reduce the impact of overcurrent phenomenon on the converter during the start -up process. In this paper, a simple and novel precharging control strategy is proposed. It can precharging all SMs of the converter at the same time, without the need for capacitor voltage balance algorithm, extra measurements and additional power supplies. It takes advantage of the symmetry of the grid voltage and the structural characteristics of MMC to form boost circuits between the arms by specific switching operations. Furthermore, the proposed method is not limited by the SM topology. The most commonly used SM topologies can also be converted into boost circuits and have the similar precharging process. By selecting appropriate control parameters, the precharging speed and efficiency of the converter can be improved. The effectiveness of the proposed control strategy is verified by simulations and experiments.

In this paper, a model is proposed for the optimal operation of multi-energy microgrids (MEMGs) in the presence of solar photovoltaics (PV), heterogeneous energy storage (HES) and integrated demand response (IDR), considering technical and economic ties among the resources. Uncertainty of solar power as well as the flexibility of electrical, cooling and heat load demand are taken into account. A p-efficient point method is applied to compute PV power at different confidence levels based on historical data. This method converts the uncertain PV energy from stochastic to deterministic to be included in the optimization model. The concept of demand response is extended and mathematically modeled using a linear function based on the quantized flexibility interval of multi-energy load demand. As a result, the overall model is formulated as a mixed-integer linear program, which can be effectively solved by the commercial solvers. The proposed model is implemented on two typical summer and winter days for various cases. Results of case studies show the important benefits for maximum PV utilization, energy efficiency and economic system operation. Moreover, the influence of the different confidence levels of PV power and effectiveness of IDR in the stochastic circumstances are addressed in the optimization-based operation.

AIM:To compare the clinical outcomes of wavefront-guided and wavefront-optimized laser in situ keratomileusis(LASIK)to correct myopia and myopic astigmatism in patients with a preoperative total ocular higher-order aberrations(HOAs)lower than 0.3μm. METHODS:In this prospective study, 60 eyes of 30 patients with myopia with or without astigmatism in our department were included. One eye of each patient was randomized to undergo wavefront-guided LASIK, and the fellow eye received wavefront-optimized LASIK. Postoperative outcome measures at 6mo included visual acuity, refraction, ocular HOAs, and contrast sensitivity under mesopic condition. Paired t-test and χ2 test were used to analyze the data. RESULTS:Six months postoperatively, 93% of eyes in the wavefront-guided group and 90% in the wavefront-optimized group had uncorrected visual acuity of 5.0 or better; 87% and 83%, respectively, had a postoperative spherical equivalent refraction of ±0.50D diopter. The differences were not statistically significant(P>0.05). No eye in either group lost 2 lines or more BCVA. Total HOAs, spherical aberration and coma increased in both groups postoperatively(PP>0.05). Contrast sensitivity under mesopic conditions in both groups recovered to preoperative levels at all spatial frequencies at 6mo postoperative(P>0.05). CONCLUSION:For eyes with preoperative HOAs lower than 0.3μm, wavefront-guided LASIK and wavefront-optimized LASIK can provide similar results in terms of visual acuity, refraction, HOAs, and contrast sensitivity.

AIM:To investigate the effect of a Chinese medicine(Qi Ming granule)on the retinal and choroidal circulation in diabetes patients. METHODS: According to the results of fundus fluorescein angiography(FFA), all the 45 diabetes patients were divided into no diabetic retinopathy(NDR)group and nonproliferative diabetic retinopathy(NPDR)group. All subjects were examined by FFA and indocyanine green angiography(ICGA)at the same time. After taken Qi Ming granule for 3mo, all subjects were examined by the same method. FFA and ICGA were used to evaluate the retinal and choroidal circulation and their features. The key points were filling time for the retinal and choroidal circulation before and after treatments. The accuracy data was used to evaluate the effect.RESULTS: After taken Qi Ming granule for 3mo, there were significant decrease of the retina and the choroid filling time in NDR and NPDR groups. The occurrence rate of various abnormal angiographic features were significantly decreased. CONCLUSION: Qi Ming granule can accelerate the blood flow of retina and choroid, improve the blood circulation in diabetes patients, and delay the occurrence and development of diabetic retinopathy.

With the increasing integration of rooftop photovoltaic (PV) generation and plug-in electric vehicles (EVs) into the households at user level, household consumers become prosumers. The coordination between the household prosumers and distribution network (DN) becomes essential to the energy management and optimal operation for both entities. In this paper, the residential prosumer cluster is considered as a residential microgrid (RMG) and a hierarchical DN integration method for the multi-RMGs is presented. A two-level hierarchical distributed optimization model is established based on the analytical target cascading to coordinate the RMGs and DNs. At the RMGs level, each RMG is required to individually optimize the energy consumption scheduling in every household by taking into account the effect of time-of-use electricity price on the demand response of EVs and flexible loads. At the DN level, the optimally coordinated operation problem is formulated as a relaxed optimal power flow model based on the second order cone programming by considering the power flow balance constraints. Case studies on the modified IEEE 33-bus system demonstrate the feasibility and effectiveness of the proposed method by achieving coordinated economic optimality as well as coordinated operating points for all entities.

For the obvious advantages in integrating wind power, multiterminal HVDC transmission system (VSC-MTDC) is widely used. The priority control strategy is proposed in this paper considering the penetration rate of wind power for the AC grid. The strategy aims to solve the problems of power allocation and DC voltage control of the DC system. The main advantage of this strategy is that the demands for wind power of different areas can be satisfied and a power reference for the wind power trade can also be provided when wind farms transmit active power to several AC grids through the DC network. The objective is that power is well distributed according to the output power of wind farm with the demand of AC system and satisfactory control performance of DC voltage is obtained.

AIM: To investigate diabetic choroidal hemodynamics in order to provide valuable theories for preventing and treating diabetic retinopathy(DR)and make compensation for the ocular disease of diabetes mellitus(DM). METHODS: Color Doppler flow imaging(CDFI)was used to quantitate peak systolic velocity(PSV), end diastolic velocity(EDV)and resistence index(RI)of the ophthalmic artery(OA), the temporal posterior ciliary artery(PCA1), and nasal posterior ciliary artery(PCA2), in the control group(15 patients)and 45 DM patients. Statistic software was used to analysis the hemodynamic parameters. RESULTS: Relative to the control, the EDV, PSV and RI have changed in non-diabetic retinopathy(NDR), non- proliferative diabetic retinopathy(NPDR)and proliferative diabetic retinopathy(PDR), and the differences are more evident according to the severity of DR. CONCLUSION: We conserved the choroidal circulatory properties of DM. CDFI is very valuable to evaluate the hemodynamic changes in diabetic eyes, and has important significance in the early impression of diabetic choroidopathy.