A compact solid-state high repetition rate trigger based on a spiral generator.

The trigger generator made with a spiral generator (SG) has the advantages of light weight, compact structure, and low cost and has promising applications in the pulsed power field. This paper introduces a compact solid-state high-voltage pulse trigger system based on an improved SG, which has improved repetition rate and lowered the demands for semiconductor switches' maximum current and current rise rate when compared with previous studies. The improvement is achieved by winding outward an additional layer of the passive layer and low-voltage metal strip, which realizes a significant reduction of the peak current and current rise rate of the discharge switch. The final dimension of the trigger is 25 × 10 × 10 cm3, excluding the power supply. An experiment carried out in single shot mode shows that the peak value of the output pulse can reach 50 kV with a leading edge of 57 ns. Repetitive experiments were carried out up to 1 kHz, with the peak voltage of the output pulse being 30.5 kV, the leading edge being 48 ns, and the jitter being 0.84 ns. Finally, the generator is used to trigger a gas switch, and it works stably and reliably.

Study on a rotational symmetry structure pulse forming network with low-impedance for compact pulse drivers.

A pulse forming network (PFN) is a significant component, contributing a lot to the overall dimension of pulse generators. In order to both reduce the size of PFN and improve the output waveform quality, this paper proposes a compact low-impedance PFN with a rotational symmetry structure. The PFN consists of four groups of Blumlein pulse forming units (PFUs) connected in parallel along the angular direction, and the spline curve structure is applied in each PFU, which achieves a higher space utilization rate. The theoretical maximum energy density of PFN is 6.6 J/L as the dimensions of PFN are φ500 × 138 mm. Field-circuit co-simulation is carried out based on the spatial model of PFN and the double switch modulation circuit to analyze the effects of switch delay time (time between main switch and steep discharge switch), as well as the output port position affecting the output pulse waveform. The results show that the PFN is appropriate to achieve quasi-square wave pulse modulation as the switch delay time is 290 ns with the output port positioned at the periphery. The verification experiments are also carried out. The results show that the PFN can generate a quasi-square wave pulse with an output voltage of 49.6 kV, a pulse width of 83 ns, and a peak power of 1 GW on a matched load. The output pulse exhibits a distinct flat top, with the fluctuation of the plateau being less than 3%.

Chitosan modulated engineer tin dioxide nanoparticles well dispersed by reduced graphene oxide for high and stable lithium-ion storage.

Tin based materials are widely investigated as a potential anode material for lithium-ion batteries. Effectively dispersing SnO2 nanocrystals in carbonaceous supporting skeleton using simplified methods is both promising and challenging. In this work, water soluble chitosan (CS) chains are employed to modulate the redox coprecipitation reaction between stannous chloride (SnCl2) and few-layered graphene oxide (GO), where the excessive restacking of the corresponding reduced graphene oxide sheets (RGO) has been effectively inhibited and the grain size of the in-situ formed SnO2 nanoparticles have been significantly controlled. In particular, the CS molecules are gradually detached from the RGO sheets with the GO deoxygenation process, leaving only a small quantity of CS remnants in the intermediate SnO2@CS@RGO sample. The final SnO2/CSC/RGO sample with significantly improved microstructure is synthesized after a simple thermal treatment, which delivers a high specific capacity of 842.9 mAh g-1 at 1000 mA·g-1 for 1000 cycles in half cells and a specific capacity of 410.5 mAh g-1 at 200 mA·g-1 for 100 cycles in full cells. The reasons for the good lithium-ion storage performances for the SnO2/CSC/RGO composite have been studied.

Spatiotemporal variations and relationships of absorbing aerosol-radiation-gross primary productivity over China.

High-load carbonaceous and dust aerosols can significantly reduce direct radiation (DIRR), which would affect photosynthesis in terrestrial ecosystems, thereby further affecting the productivity of vegetation. Based on this, a variety of remote sensing data were used to study the spatiotemporal distributions and changing tendencies of the absorbing aerosols, CO, DIRR, and gross primary productivity (GPP) in China during 2005-2019; then, the relationships were analyzed between different types of absorbing aerosols and DIRR as well as GPP. The results showed that the annual mean absorbing aerosols index (AAI) in China during 2005-2019 was 0.39, with a slow growth rate of 0.02 year-1, and the emission of CO showed a decreasing trend with each passing year, especially in North China Plain and Sichuan Basin. Carbonaceous and dust aerosols were predominantly bounded by Hu line. The east of Hu line was the dominant area of carbonaceous aerosols, and the west of Hu line was the topographical region of dust aerosols. Near the Hu line was the dominant area of carbonaceous-dust aerosols. However, the Karamay-Urumqi-Hami area and Northeast China Plain were exceptional. During the vegetation growing season, different types of absorbing aerosols significantly negatively affected GPP. From a perspective of regional scale variation pattern, the negative effect of absorbing aerosols on vegetation productivity was the most significant in Northeast China; from the perspective of the effects of different vegetation types, the negative effect of absorbing aerosols on grasslands was greater than that of woodlands; from the perspective of the composition characteristics of aerosols, the negative effect of dust aerosols on GPP was greater than that of carbonaceous aerosols.

[Relationship between functional diversity and ecosystem multifunctionality of alpine meadow along an altitude gradient in Gannan, China]. / ç”˜å—é«˜å¯’è‰ç”¸æµ·æ‹”æ¢¯åº¦ä¸ŠåŠŸèƒ½å¤šæ ·æ€§ä¸Žç”Ÿæ€ç³»ç»Ÿå¤šåŠŸèƒ½çš„å ³ç³».

Relationship between plant community functional diversity and ecosystem multifunctionality (EMF) was a new area of ecological research in recent years. Previous studies had mostly focused on the relationship between plant community functional diversity and individual ecosystem function, and lack of understanding of the EMF. In this study, six functional indices of aboveground biomass, soil organic carbon, soil total nitrogen, soil total phosphorus, soil available nitrogen and soil available phosphorus of Gannan alpine meadow were selected to analyze the relationship between plant community functional diversity and EMF on the altitude gradient of Gannan alpine mea-dow by using Bartlett sphericity test and multi-threshold method. The results showed that there was significant altitudinal difference in plant community composition, with species richness and plant coverage at 3500 m were significantly higher than those at other altitudes. Single and multi-functional diversity decreased with the increases of altitude, with significant difference among altitudes. Redundancy analysis showed that single and multi-functional richness, functional evenness and Rao's quadratic entropy were significantly positively correlated with soil temperature, soil water content and soil bulk density, and significantly negatively correlated with soil pH and soil conductivity. In a large threshold range (6%-89%), functional diversity had a significant positive effect on EMF. Based on correlation analysis, optimal regression model and random forest model, it was found that multi-functional richness index had a significant positive relationship with EMF, and that multi-functional richness was also the main driving factor of EMF. Overall, functional richness had the most significant impact on the EMF of alpine meadow in the Qinghai-Tibet Plateau.

A narrative review on the research progress of gonadal function protection in children with cancer.

Background and Objective: The global incidence of malignant tumors in children (0-14 years) and adolescents (15-19 years) ranges between 95 per 1 million and 255 per 1 million, which seriously affects the survival of patients. In the past 30 years, with the application of comprehensive treatments (including surgery, chemotherapy, radiotherapy, and bone marrow transplantation), great progress has been made in the treatment of malignant tumors in children and adolescents. The 5-year survival rate now exceeds 80%, and most patients can smoothly enter adolescence or the reproductive period. However, due to the particular age of patients with malignant tumors in children and adolescents, treatment may cause abnormal growth of the patient's height, bones, and some vital organs (such as the pituitary gland and reproductive organs). Treatment may also cause abnormal secretion of growth hormones, thyroid hormones, and sex hormones. These complications seriously affect the quality of life of tumor patients. In the past ten years, countries have established long-term follow-up specifications for children with tumors. These programs have found that, in adulthood, 67% to 75% of children who survived having tumors have at least one treatment-related complication. Among patients receiving chemotherapy, gonadal dysfunction is the most common related endocrine dysfunction. Methods: This paper reviews the literature on fertility protection services for cancer patients in foreign countries was conducted to provide a reference for developing gonadal protection services for cancer patients and for establishing consensus or guidelines on gonadal protection in China. Key Content and Findings: In the treatment of childhood cancer, the assistance of reproductive technology can effectively reduce the occurrence of complications from treatment. Conclusions: Therefore, minimizing the effects of radiotherapy and chemotherapy on the growth and endocrine of children and adolescents while treating tumors is a new challenge for oncologists.

A case report of precocious puberty related to Rett syndrome and a literature review.

Rett syndrome is an X-linked dominant disorder, and the typical phenotype includes intractable epileptic seizures and severe mental retardation, in particular, a rapid regression in language and limited progress in psychomotor development. Premature breast and pubic hair development and advanced bone age are signs of precocious puberty (PP), defined as puberty occurring before 8 years of age in girls. There are rare reports about precious puberty associated with Rett syndrome. Herein, we report the case of a patient with Rett syndrome with precocious puberty. Her first signs of PP occurred 6 months prior to presentation (at 7.5 years old), and the laboratory measurements, including tests of bone age and gonadotropin-releasing hormone stimulation, were positive for PP. PP was controlled after treatment with leuprorelin 3.75 mg for one year. In addition, the genetic and phenotypic spectrum of previously reported cases of Rett syndrome with precocious puberty are reviewed and summarized.

A narrative review of mechanisms of ferroptosis in cancer: new challenges and opportunities.

OBJECTIVE: This article reviews the specific mechanism of ferroptosis in cancer and introduces in detail the opportunities and challenges of ferroptosis-based cancer therapy, aiming to provide a new research direction for tumor therapy. BACKGROUND: Ferroptosis is a newly discovered programmed non-apoptotic form of cell death. Involving changes in metabolic processes and the accumulation of peroxidation caused by factors such as drugs or genes which destruct the cell membrane structure, this kind of cell death has been linked with the pathological process of diseases such as tumors, neurological diseases, ischemia-reperfusion injury, kidney injury, and hemopathy. This kind of cell death can play a vital role in inhibiting tumorigenesis by eliminating the adaptive characteristics of malignant cells and removing cells that are unable to obtain key nutritional factors or are infected and damaged by environmental changes. The present focus of research on the regulation of ferroptosis-related diseases involves the use of small molecule compounds. METHODS: We described the mechanism of ferroptosis and its related small molecules compounds, which involved in the regulatory mechanism, and analyzed the role and regulatory mechanism of ferroptosis in different tumors. CONCLUSIONS: This article reviewed the mechanism of ferroptosis and its role and mechanism in different tumors, and showed it can inhibit the occurrence and development of different tumors and may reduce the adverse effects of current treatment methods.

Theoretical Design of Inorganic Flexible Bulk Photovoltaic Materials.

Current flexible photovoltaics (PVs) are usually based on low-dimensional structures of inorganic semiconductors and hybrid perovskites, as well as organic materials. Here, we propose a type of inorganic flexible bulk PV material, evaluating its structure flexibility, electronic structure, and PV efficiency in the framework of density functional theory, suggesting α-Ag2S as the best candidate. It is found that the band structure and effective masses of α-Ag2S can be significantly modulated by external strain, whereas leaving the high PV efficiency was not affected much. The flexibility of α-Ag2S can be further enhanced by applying electron doping during stretching or applying hole doping during compression. We further studied the intrinsic defect properties of α-Ag2S by using the Heyd-Scuseria-Ernzerhof hybrid functional, and the calculation results show that α-Ag2S is a defect-tolerant semiconductor even when an external strain is applied. Our results open the door for searching inorganic flexible bulk PV materials for robust flexible solar cells.

Menkes disease diagnosed by a novel ATP7A frameshift mutation in a patient with infantile spasms-a case report.

Menkes disease (MD) is a rare congenital copper deficiency disease caused by an adenosine triphosphatase copper transporting alpha (ATP7A) gene mutation. It is a progressive and systemic disease that primarily involves the central nervous system and connective tissues. The clinical manifestation of these patients with MD is curly hair, progressive muscle tone reduction, and convulsions, and often leads to death in early infancy. Herein, we present a case of a 9-month-old Chinese male who displayed developmental regression, followed by convulsions, which were characterized by infantile spasms (ISs). The proband also had curly hair, hypopigmented skin, cutis laxa, decreased muscle tone, and micrognathia. The patient's ceruloplasmin levels were below the reference values. Brain magnetic resonance imaging (MRI) showed abnormal signals bilaterally that were symmetrically distributed in the caudate nucleus, globus pallidus, and subcortical white matter of the temporal parietal cortex, white matter in the anterior and posterior corners of the ventricles and the anterior limb of the internal capsule. The electroencephalograph (EEG) showed hypsarrhythmia. Genetic testing revealed a novel frameshift mutation in the ATP7A gene exon 13 and premature termination codon. Copper replacement therapy was initiated after the delayed diagnosis was established. However, the patient still died several months later due to disease progression. Our case reveals a novel frameshift mutation of the ATP7A gene, which expands the gene spectrum of MD. The infants with uncontrollable convulsions, regressive development, curly hair, MD should be considered at early stage and also need the further genetic analysis to confirm MD finally. The correct and timely diagnosis and initiating copper replacement therapy may improve the prognosis.

[Spatio-temporal Patterns and Potential Sources of Absorbing Aerosols in the Fenwei Plain].

Air quality has gradually improved in many parts of China; however, air pollution is become more severe in the Fenwei Plain. Using OMI/Aura OMAERUV L2 and PM2.5 data, spatial autocorrelation analysis and back trajectory modeling were used to explore the spatio-temporal patterns of absorptive aerosols over the Fenwei Plain, and the dominant types, transmission paths, and potential source areas were identified. The main results can be summarized as follows:① Annual mean absorbing aerosol index (AAI) values increased between 2005 and 2019, with high period occurring in 2006, 2013, and 2017, with values exceeding 0.63. Xi'an and Linfen were identified as a 'high-high' cluster, with AAI showing poor spatial stability and a 15.3% increase in area over the past 15 years. In contrast, the area connecting Xi'an and Linfen, which occupies 24.2% of the total area of the region, was identified as a 'low-low' cluster, with a sharp drop of 6.2% in area; ② The Fenwei Plain has high AAI values across a large area in winter, exceeding 0.8 in Linfen and Xi'an, and 91.5% of the study area exceeding 0.6. Values were lower in spring (AAI>0.4) and autumn (AAI>0.3), with the lowest values occurring in summer. The atmospheric diffusion conditions in spring, autumn, and winter are poor, associated with anticyclonic high-pressure events. The observed high AAI values were significantly affected by atmospheric diffusion conditions, temperature, and precipitation; ③ Back trajectory and source contribution modeling showed that long-range transport of air masses from Xi'an and Linfen occurs from the northwest, and short-range transport air masses occurs from the east and south. Two long-range sand and dust source areas were determined (with northwestern and northern wind sources); two carbon source areas were identified (with eastern and southern wind sources); and one combined sand and carbon source area was identified (from the Loess Plateau). Of these sources, the northwestern wind source, the Loess Plateau, and the southern wind source have significant influence in Xi'an, and the eastern wind source and the Loess Plateau have a significant impact on Linfen. Linfen is little affected by the northwestern wind source and the dust from the northern wind source. Based on the spatial distribution of CO and its correlation with AAI, it is concluded that cardon in the dominant absorbent aerosol in Linfen dust and carbon are most important in Xi'an.

Two-dimensional topological insulators exfoliated from Na3Bi-like Dirac semimetals.

Topological insulation is widely predicted in two-dimensional (2D) materials realized by epitaxial growth or van der Waals (vdW) exfoliation. Such 2D topological insulators (TI's) host many interesting physical properties such as the quantum spin Hall effect and superconductivity. Here, we extend the search of 2D TI's into the exfoliatable non-vdW 2D crystals. We find that three-dimensional Dirac semimetals A3Bi (A = Na, K, Rb) (P3[combining macron]c1) can be exfoliated into 2D materials with exfoliation energies of 0.479-0.990 J m-2. Our careful examination of the topological invariants of exfoliated A3Bi monolayers/multilayers by using two well-established approaches reveals that bilayer and tetralayer Na3Bi are 2D TI's. It is found that the band gap of 2D TI's can be significantly increased by external strain. We further find that the predicted 2D TI's possess interesting hidden Rashba-like spin textures. Our results suggest a new arena to search for two-dimensional topological insulators and spintronic materials.

Study on the action mechanism of Wuling Powder on treating osteoporosis based on network pharmacology.

Osteoporosis is a health problem to cause global concern. A lot of methods have been used to prevent and treat osteoporosis, but there is still a lack of effective treatment for osteoporosis owing to limited understanding of its mechanism. Therefore, the aim of this present study is to explore the underlying mechanism of Wuling Powder, a traditional Chinese medicine on treating osteoporosis. In this study, we firstly screened and identified the common targets between Wuling Powder and osteoporosis through the related databases, and then explored the relationships among these targets, Wuling Powder and osteoporosis by using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and network analyses. Subsequently, the molecular docking was performed by using systemsDock to evaluate the potential binding relationships between the active components of Wuling Powder and their related targets. The results showed that in total of 14 common targets including CREBBP, ADAM17, GOT1, GAPDH, USP8, ERBB2, EEF1A1, MTOR, RAC1, ETS1, DDX58, GCK, EGF and S100A8 were screened. EGF, ERBB2, MTOR and HIF-1 were the potential therapeutic targets for osteoporosis, and they were also the related targets for predicting active components in Wuling Powder. Taken together, we concluded that Wuling Powder might be used to treat osteoporosis through above these targets.

Copper substituted zinc ferrite with abundant oxygen vacancies for enhanced ciprofloxacin degradation via peroxymonosulfate activation.

In this paper, copper substituted zinc ferrite (ZCFO) catalyst with rich oxygen vacancies (OVs) was synthesized via a simple one pot sol-gel combustion method, and firstly used for peroxymonosulfate (PMS) activation to degrade a typical antibiotic ciprofloxacin (CIP). Only ∼15 min was required to achieve 96.6% of CIP degradation using ZCFO as the catalyst, and the pseudo-first-order reaction constant was about 95 times higher than that of conventional zinc ferrite (1.90 min-1 vs 0.02 min-1). ZCFO catalyst showed great stability and reusability based on the successive degradation cycles and could be easily recovered through magnetic separation. Besides, the effects of catalyst loading, PMS concentration, reaction temperature, initial solution pH, coexisting anions and humic acid (HA) on CIP degradation were systematically investigated. Radical quenching tests and electron paramagnetic resonance (EPR) revealed that sulfate radical (SO4-.), hydroxyl radical (OH∙), superoxide radical (O2∙-) and singlet oxygen (1O2) were involved in the ZCFO/PMS system, among which O2∙- and 1O2 were the dominant reactive oxygen species (ROS). The excellent catalytic activity of ZCFO was ascribed to the dual active sites of Fe and Cu and large amount of OVs after Cu substitution, which was beneficial to generate ROS for CIP removal.