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Background: Transketolase (TKT), a key rate‐limiting enzyme in the non‐oxidative branch of the pentose phosphate pathway (PPP), provides more than 85% of the ribose required for de novo nucleotide biosynthesis and promotes the development of hepatocellular carcinoma (HCC). Pharmacologic inhibition of TKT could impede HCC development and enhance treatment efficacy. However, no safe and effective TKT inhibitor has been approved. Methods: An online two‐dimensional TKT protein immobilised biochromatographic system was established for high‐throughput screening of TKT ligands. Oroxylin A was found to specifically bind TKT. Drug affinity responsive target stability, cellular thermal shift assay, surface plasmon resonance, molecular docking, competitive displacement assay, and site mutation were performed to identify the binding of oroxylin A with TKT. Antitumour effects of oroxylin A were evaluated in vitro, in human xenograft mice, diethylnitrosamine (DEN)‐induced HCC mice, and patient‐derived organoids (PDOs). Metabolomic analysis was applied to detect the enzyme activity. Transcriptome profiling was conducted to illustrate the anti‐HCC mechanism of oroxylin A. TKT knocking‐down HCC cell lines and PDOs were established to evaluate the role of TKT in oroxylin A‐induced HCC suppression. Results: By targeting TKT, oroxylin A stabilised the protein to proteases and temperature extremes, decreased its activity and expression, resulted in accumulation of non‐oxidative PPP substrates, and activated p53 signalling. In addition, oroxylin A suppressed cell proliferation, induced apoptosis and cell‐cycle arrest, and inhibited the growth of human xenograft tumours and DEN‐induced HCC in mice. Crucially, TKT depletion exerted identical effects to oroxylin A, and the promising inhibitor also exhibited excellent therapeutic efficacy against clinically relevant HCC PDOs. Conclusions: These results uncover a unique role for oroxylin A in TKT inhibition, which directly targets TKT and suppresses the non‐oxidative PPP. Our findings will facilitate the development of small‐molecule inhibitors of TKT and novel therapeutics for HCC. [ABSTRACT FROM AUTHOR]

To accelerate the design of a high-power microwave device, a deep learning assisted multi-objective optimization method is used to optimize a Ka-band relativistic backward-wave oscillator (RBWO) operating with a low magnetic field. Particle-in-cell simulation results show that the optimized RBWO with a tooth-shaped slow wave structure (SWS) can generate microwave pulses with an output power of 1.24 GW and an operating frequency of 26.8 GHz under a diode voltage of 623.3 kV, and the diode current is 6.56 kA at a guiding magnetic field of 0.8 T. Compared with the original RBWO, the output power of the optimized RBWO has been increased by 201.2%, and the beam-to-microwave conversion efficiency has increased from 10.0% to 30.3%. The detailed analysis reveals that in an overmoded RBWO with low guiding magnetic fields, the introduction of a tooth-shaped SWS is beneficial to mode competition, improves output power, and decreases microwave starting time. [ABSTRACT FROM AUTHOR]

The associations between human papillomavirus (HPV) infection or hormonal exposure and cervical cancer risk are well established. However, to the best of our knowledge, the association between high endogenous estradiol levels in conjunction with HPV/HPV16 infection and the risk of cervical squamous cell carcinoma remains unknown. To investigate this, the current study conducted a matched case-control study in Shanxi Province, China, in which clinical samples were obtained from 74 females with newly diagnosed uterine cervix squamous cell carcinoma and 74 matched healthy females who were selected from 582 healthy females according to age, place of residence, marital status and menopausal status. From all participants, DNA was extracted from cells obtained from a cervical smear and serum was separated from venous blood withdrawn during days 5–8 of the menstrual cycle. HPV/HPV16 DNA and estradiol expression levels in the serum were measured by general polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Significant differences were identified in the positive HPV and HPV16 DNA expression rates between patients and controls, with odds ratios (95% confidence interval) of 3.74 (1.84–7.59) and 4.04 (1.97–8.28), respectively. Expression levels of estradiol in patients were significantly higher compared with the controls (P<0.001), however, this was only identified when the HPV16 E2 or E6 oncogene status was negative. Considering 40 ng/ml as the cut-off estradiol level, 78.38% of patients exhibited high estradiol levels, which was significantly higher than the percentage of controls (P<0.001). An additive interaction pattern was revealed between estradiol expression levels and HPV/HPV16 infection. The results suggest that among the various types of HPV, HPV16 may be most likely to cause uterine cervix squamous cell carcinoma and an abnormally high level of endogenous estradiol may further increase this risk. Therefore, estradiol therapy may represent a new treatment strategy for cases of cervical cancer associated with HPV infection. [ABSTRACT FROM AUTHOR]

Bio-fertilizers are thought to be overwhelmingly superior to chemical fertilizers for the improvement of soil quality and productivity. However, the comprehensive effects of bio-fertilizer on the soil ecosystem and the possibility of using multiple soil beneficial biota are still not well understood. A two-year field study was conducted to examine how crop yield, soil biochemical properties, enzyme activities, and functional diversity responded to different bio-fertilizers in the sweet potato phase of a double-cropping system (sweet potato and rapeseed). Six fertilizer treatments, including one chemical treatment (CF), two organic treatments (OM, organic manure; MC, organic manure plus chemical fertilizer) and three bio-fertilizer treatments (MCN containing nematodes, MCE containing earthworms, and MCP containing phosphate-solubilizing bacteria) were compared. The soils under CF had the lowest values for all soil parameters in comparison with the other treatments. Among the organic and bio-fertilizer treatments, OM performed better in improving soil biological properties such as soil respiration and microbial biomass, while soils under all these treatments had similar soil enzyme activities and functionality. Crop yield was positively correlated with soil nutrient levels, microbial biomass and enzyme activity, and most of the biochemical variables were highly intercorrelated. Our results indicated that organic fertilizers and bio-fertilizers were superior to chemical fertilizers and generally improved soil quality and productivity to similar levels in the field. [ABSTRACT FROM AUTHOR]

Folate receptor alpha (FRα) is over-expressed in numerous epithelial malignancies, however, the association between FRα and cervical cancer remains unclear. The purpose of this study was to explore the effects of FRα on cervical cancer and its regulation of the ERK signaling pathway. In this case-control study, moderate/strong expression of FRα, phosphorylated ERK1/2 (p-ERK1/2), p-c-Fos, and p-c-Jun proteins was increased with the progressive severity of cervix lesions (P < 0.05). Moreover, the expression levels of p-ERK1/2, p-c-Fos, and p-c-Jun proteins was positively correlated with those of FRα protein in cervical squamous cell carcinoma (SCC) group (P < 0.05). In vitro experiment indicated down-regulation of FRα by siRNA suppressed cell proliferation, promoted cell apoptosis, induced cell cycle arrest at G0/G1 phase, and reduced expression of p-ERK1/2, p-c-Fos, and p-c-Jun proteins. The results suggest that FRα is associated with the progression of cervical cancer and regulates cervical cancer cells growth through phosphorylating ERK1/2, c-Fos, and c-Jun, which are key factors of the ERK signaling pathway. Therefore, FRα may be an effective target for early detection and therapy of cervical cancer. [ABSTRACT FROM AUTHOR]

In some organisms, environmental stress triggers trehalose biosynthesis that is catalyzed collectively by trehalose 6-phosphate synthase, and trehalose 6-phosphate phosphatase (T6PP). T6PP catalyzes the hydrolysis of trehalose 6-phosphate (T6P) to trehalose and inorganic phosphate and is a promising target for the development of antibacterial, antifungal and antihelminthic therapeutics. Herein, we report the design, synthesis and evaluation of a library of aryl d -glucopyranoside 6-sulfates to serve as prototypes for small molecule T6PP inhibitors. Steady-state kinetic techniques were used to measure inhibition constants (K i ) of a panel of structurally diverse T6PP orthologs derived from the pathogens Brugia malayi , Ascaris suum , Mycobacterium tuberculosis , Shigella boydii and Salmonella typhimurium . The binding affinities of the most active inhibitor of these T6PP orthologs, 4- n -octylphenyl α- d -glucopyranoside 6-sulfate ( 9a ), were found to be in the low micromolar range. The K i of 9a with the B. malayi T6PP ortholog is 5.3 ± 0.6 μM, 70-fold smaller than the substrate Michaelis constant. The binding specificity of 9a was demonstrated using several representative sugar phosphate phosphatases from the HAD enzyme superfamily, the T6PP protein fold family of origin. Lastly, correlations drawn between T6PP active site structure, inhibitor structure and inhibitor binding affinity suggest that the aryl d -glucopyranoside 6-sulfate prototypes will find future applications as a platform for development of tailored second-generation T6PP inhibitors. [ABSTRACT FROM AUTHOR]

In this study, trehalose 6-phosphate phosphatase (T6PP) was targeted for inhibitor development. T6PP catalyzes the hydrolysis of trehalose-6-phosphate to form trehalose and inorganic phosphate, a reaction essential to important fungal, bacterial, and nematodal pathogens. At the current time, there are no specific inhibitors of T6PP available to serve as tools for interrogating its structure and function nor as leads for pharmaceutical applications. Herein, we describe the synthesis of non-hydrolysable mimics of trehalose-6-phosphate, which incorporate 6-sulfate ( 1 ), -phosphonate ( 2 ), -fluorophosphonate ( 3 ) and –boronate ( 4 ) groups in place of the 6-phosphate moiety of the substrate. The inhibitory efficacies of these adducts were evaluated against trehalose 6-phosphate phosphatases selected from evolutionarily distant pathogenic bacteria and nematodes. Phosphonates 2 and 3 were found to display good inhibitory activities against the T6PPs, while the sulfate analog, trehalose-6-sulfate, proved to be a particularly effective broad-spectrum inhibitor of these phosphatases and an ideal prototype for optimization. [ABSTRACT FROM AUTHOR]

We investigated the use of single-stepped cavities instead of typical tapered cavities in an A6 magnetron with diffraction output (MDO) and a 12-cavity MDO through particle-in-cell (PIC) simulations using MAGIC [1] and UNIPIC [2] in our earlier publications [3]–[5]. The interaction space, where the charged particles interact with the induced RF waves, was increased by replacing tapered cavities with single-stepped cavities in a 12-cavity rising-sun relativistic magnetron with diffraction output (RMDO) that the electronic efficiency of \pi -mode generation in a 12-cavity rising-sun RMDO with single-stepped cavities driven by a transparent cathode [6] with gigawatt output power level can be as high as 83% for \alpha = 12.5^{\circ } , 79% for \alpha = 17.5^{\circ } , and 82% for \alpha = 18.2^\circ at \beta = 32^\circ , where \alpha is the angle between the inner wall and the z -axis, and \beta is the angle between the outer wall and the z -axis. When \alpha , the angle between the inner wall and the z -axis, is changed, the depth of single-stepped cavities was changed. This would lead to the coupling between deep cavities and shallow cavities in the 12-cavity rising-sun MDO changing too, and which finally results in different frequencies of magnetron operation in the \pi and \beta = 32^\circ , the peak efficiency of \pi -mode generation in a 12-cavity rising-sun MDO with single-stepped cavities design is around 82% and occurs for voltage $V\sim 400$ kV ± 50 kV. This paper describes optimizing the parameters in a 12-cavity rising-sun RMDO for the desired $\pi $ -mode operation. [ABSTRACT FROM AUTHOR]

An extension of a first-principle combined Monte Carlo method is proposed in this work to obtain the secondary electron emission characteristics of anisotropic crystal Al2O3. Unlike isotropic crystal Cu, density functional theory calculations reveal that the q-dependent energy loss function of Al2O3 in all directions is different. Therefore, an interpolation algorithm is introduced in the Monte Carlo method to determine the loss of energy and inelastic mean free path of electrons. The simulation results are in good agreement with experimental data. This method can be further used to simulate the secondary emission yield of other anisotropic crystal materials. [ABSTRACT FROM AUTHOR]

Two-mode interference effects in slot waveguides have been predicted and investigated through plane wave expansion and finite-difference time-domain methods. A broadband 1×2 power splitter (PS) based on this effect is presented, and its transmission characteristics are investigated by using finite-difference time-domain method. Calculated results indicate that, for the 1×2 PS whose interaction length is as short as 0.509 µm, the high transmission (≥95%) is observed within a wavelength range of 1.389–1.747 µm, corresponding to a relative bandwidth of 22.87%. Combining three 1×2 PS, we construct a 1×4 PS with excellent transmission characteristics. Those simple PS are expected to be applied to highly dense photonic integrated circuits. [ABSTRACT FROM AUTHOR]

Two kinds of MnO 2 /graphene nanocomposites (M1 and M2) were synthesized by two different reaction procedures. M1 was synthesized as follows: the plate-like MnO 2 /graphene nanocomposite was obtained by using hydrazine reduction of MnO 2 /graphene oxide. M2 was formed as follows: the plate-like MnO 2 nanospheres was synthesized on the graphene nanosheet which was reduced by hydrazine reduction of graphene oxide. The M1 have a good electrochemical performance and the average capacitance is as high as 250.6 F g −1 at 1 A g −1 in 1 mol L −1 Na 2 SO 4 electrolyte, which is higher than that of the M2 (206.8 F g −1 ). [ABSTRACT FROM AUTHOR]

The possibility of using single-stepped cavities to replace the common tapered cavities was studied using particle-in-cell simulations in an A6 magnetron with diffraction output (MDO). The replacing of the tapered cavities by the single-stepped cavities in a 12-cavity MDO increases the interaction space where the charged particles interact with the induced RF waves. The electronic efficiency of the 12-cavity MDO with single-stepped cavities driven by the transparent cathode [2] of GW output power level can be as high as 73% for \alpha=18.2^\circ , 74% for \alpha=17.5^\circ , and 72% for \alpha=12.5^\circ at \beta=32^\circ , where $\alpha$ is the angle between the outer wall and z$ -axis, and \beta$ is the angle between the inner wall and z$ -axis. The depth of single-stepped cavities is changed when \alpha . The results presented in this paper provide references for relativistic magnetron mode selection or mode switching experiments when choosing the input parameters (magnetic field and accelerating voltage) allowing the magnetron to operate in the desired operation mode. [ABSTRACT FROM PUBLISHER]

Highlights: [•] Different PANI/GO nanocomposites were prepared through chemical polymerization method. [•] We found the unique morphology of Mace-like PANI/GO composite when the mass ratio (m ANI:m GO) was 1000:1. [•] The Mace-like PANI/GO nanocomposite has a high specific capacitance (355.2Fg−1 at 0.5Ag−1). [•] The Mace-like PANI/GO nanocomposite exhibited the excellent electrochemical stability even after 1000 cycles. [ABSTRACT FROM AUTHOR]

Abstract: A fundamental dual-channel wavelength division de-multiplexer (WDDM) based on directional coupling of one-dimensional photonic crystal waveguides is presented, and its transmission characteristics of the WDDM are investigated by using finite-difference time-domain method. Calculated results indicate that for this WDDM, without any structural optimization, a high transmittance of more than 95% is observed at output ports. Combining the fundamental dual-channel WDDM with flexible bends of one-dimensional photonic crystal waveguides, we construct a simple and compact four-channel WDDM. Those WDDMs are expected to be applied to highly dense photonic integrated circuits. [Copyright &y& Elsevier]

Aberrant mucin O-glycosylation is a pathological alteration that is widespread in cancer. The UDP-N-acetyl-D-galactosamine polypeptide N-acetylgalactosaminyltransferases (ppGalNAc-T) family of enzymes regulates the initial key steps of mucin O-glycosylation. ppGalNAc-T2, as a member of the ppGalNAc-T family, was recently described as an altered expression in oral squamous cell carcinoma and colorectal and breast carcinoma. In order to gain further insight into the role of ppGalNAc-T2, we produced the anti-human ppGalNAc-T2 monoclonal antibody (MAb) 5F3. The IgM κ isotype of this MAb was further characterized using ELISA, Western blot analysis, flow cytometry, and immunofluorescent staining. In the present study, MAb 5F3 can specifically recognize human ppGalNAc-T2 protein in various formats by Western blot analysis, flow cytometry, and immunofluorescent staining. For the first time, it was shown that both Jurkat and HepG2 cell lines clearly express ppGalNAc-T2. [ABSTRACT FROM AUTHOR]

As biomolecules vibrate and rotate in the terahertz band, the biological effects of terahertz electromagnetic fields have drawn considerable attention from the physiological and medical communities. Ion channels are the basis of biological electrical signals, so studying the effect of terahertz electromagnetic fields on ion channels is significant. In this paper, the effect of a terahertz electromagnetic field with three different frequencies, 6, 15, and 25 THz, on the Kv1.2 potassium ion channel was investigated by molecular dynamics simulations. The results show that an electromagnetic field with a 15 THz frequency can significantly enhance the permeability of the Kv1.2 potassium ion channel, which is 1.7 times higher than without an applied electric field. By analyzing the behavior of water molecules, it is found that the electromagnetic field with the 15 THz frequency shortens the duration of frozen and relaxation processes when potassium ions pass through the channel, increases the proportion of the direct knock-on mode, and, thus, enhances the permeability of the Kv1.2 potassium ion channel. [ABSTRACT FROM AUTHOR]

[Display omitted] Several boron-containing small molecules have been approved by the US FDA to treat human diseases. We explored potential applications of boron-containing compounds in modern agriculture by pursuing multiple research and development programs. Here, we report a novel series of multi-substitution benzoxaboroles (1 – 36), a compound class that we recently reported as targeting geranylgeranyl transferase I (GGTase I) and thereby inhibiting protein prenylation (Kim et al., 2020). These compounds were designed, synthesized, and tested against the agriculturally important fungal pathogens Mycosphaerella fijiensis and Colletotrichum sublineolum in a structure–activity relationship (SAR) study. Compounds 13 , 28 , 30 , 34 and 36 were identified as active leads with excellent antifungal MIC 95 values in the range of 1.56–3.13 ppm against M. fijiensis and 0.78–3.13 ppm against C. sublineolum. [ABSTRACT FROM AUTHOR]

An improved method was developed for the efficient, large-scale synthesis of α,α′-trehalose-6-phosphate starting with α,α′-trehalose. In the sequence, octa-trimethylsilylation of α,α′-trehalose is followed by selective removal of the 6- O -trimethylsilyl protecting group. Reaction of the mono-alcohol with (PhO) 2 POCl is then followed by simultaneous hydrogenolysis and per-desilylation to generate α,α′-trehalose-6-phosphate, free of contamination by inorganic phosphate. [ABSTRACT FROM AUTHOR]

Background and Aim: Cold snare polypectomy (CSP) has received increasing attention in recent years, but few studies have assessed defect repair after polypectomy. Therefore, we compared the repair of mucosal defect after CSP and hot snare polypectomy (HSP) in a rabbit model. Methods: Resection of normal colonic mucosa using both HSP and CSP were performed in 40 male New Zealand white rabbits by an experienced endoscopist. Follow‐up colonoscopy was performed after 7 and 15 days by another endoscopist. We assessed mucosal defect repair, status of healing, scar formation, and intraoperative or delayed complications (including perforation and bleeding). Results: Eight animals died of intraoperative or delayed perforation; follow‐up colonoscopy was performed in 32 animals. On follow‐up colonoscopy at 7 days after operation, 78.1% cases in the CSP group showed healing of mucosal defect compared with none in the HSP group (P < 0.001); mucosal repair score in the CSP group was significantly higher than HSP group (P < 0.001). On follow‐up colonoscopy at 15 days, mucosal defect after CSP had completely healed in all cases (100%) versus 96.9% after HSP (P = 0.313). Among these healed defects, scar formation was observed in 2 of 32 cases in the CSP group compared with 19 of 31 in the HSP group (P < 0.001). Intraoperative perforation rate was significantly higher in the HSP group (15% vs 2.5%; P = 0.048). Conclusions: Mucosal defect repair after CSP is quicker compared with HSP and is more likely to result in scarless healing. HSP is more likely to cause perforation in the thin colon walls. [ABSTRACT FROM AUTHOR]

Thrombocytopenia is a critical complication after radiation therapy and exposure. Dysfunction of megakaryocyte development and platelet production are key pathophysiological stages in ionizing radiation (IR)-induced thrombocytopenia. Protein kinase C (PKC) plays an important role in regulating megakaryocyte development and platelet production. However, it remains unclear how PKC regulates IR-induced megakaryocyte apoptosis. In this study, we found that pretreatment of PKC pan-inhibitor Go6983 delayed IR-induced megakaryocyte apoptosis, and inhibited IR-induced mitochondrial membrane potential and ROS production in CMK cells. Moreover, suppressing PKC activation inhibited cleaved caspase3 expression and reduced p38 phosphorylation levels, and IR-induced PKC activation might be regulated by p53. In vivo experiments confirmed that Go6983 promoted platelet count recovery after 21 days of 3 Gy total body irradiation. Furthermore, Go6983 reduced megakaryocyte apoptosis, increased the number of megakaryocyte and polyploid formation in bone marrow, and improved the survival rate of 6 Gy total body irradiation. In conclusion, our results provided a potential therapeutic target for IR-induced thrombocytopenia. [ABSTRACT FROM AUTHOR]

Potassium (K) channels show the highest variability and most frequent alterations in expression in many tumor types, and modulation of K+ channels may represent a new window for cancer therapy. In previous work, we found that a terahertz (THz) field incident along the z-axis with a frequency of 51.87 THz increased the ion flux through K+ channels. In practice, it is difficult to ensure that the incident electromagnetic (EM) wave is strictly parallel to the direction of channel ion flow. In this paper, we found by changing the direction of the applied electric field that the EM wave of a specific frequency has the largest ion flux when the incident direction is along the ion flow, and the smallest ion flux when the incident direction is perpendicular to the ion flow, and that overall the EM wave of this frequency enhances the ion flow of the K+ channel. Changes in the direction of the applied field at a specific frequency affect the stability of the φ dihedral angle of the GLY77 residue and alter the ion permeation mechanism in the selectivity filter (SF) region, thus affecting the ion flux. Therefore, this frequency can be used to modulate K+ fluxes by THz waves to cause rapid apoptosis in potassium-overloaded tumor cells. This approach consequently represents an important tool for the treatment of cancer and is expected to be applied in practical therapy. [ABSTRACT FROM AUTHOR]

Cyclic thrombocytopenia (CTP) is a rare blood disorder characterized by periodic fluctuations in platelet counts. CTP usually appears in pre-menopausal women, and these fluctuations of platelets are in phase with the menstrual cycle. CTP is a heterogeneous disease, and the pathogenic mechanism is still unclear. Therefore, it harbors great significance for exploring the association of fluctuations in platelet counts with hormonal-cycle. Firstly, we washed human platelets from healthy volunteers following the Declaration of Helsinki. Flow cytometer was employed to measure the mitochondrial inner transmembrane potential (ΔΨm) depolarization, PS exposure, P-selectin expression, and GPIIb/IIIa activation in platelets. In addition, western blot detected the related protein expression. The corresponding assay kit measured the caspase-3 and PDE3A activity. Finally, flow cytometry determined mouse platelets labeled with calcein. We find a reverse relationship between the platelet count and serum estradiol (E2) level in a CTP patient. We demonstrated that E2 induces platelet apoptosis in vitro and platelet clearance in vivo. We further discovered that E2 activates phosphodiesterase 3A, which inhibits protein kinase A (PKA), leading to PKA-mediated platelet apoptosis. Activation of PKA protected platelets from E2-induced thrombocytopenia and elevated the number of mice circulatory platelets. We find that E2 induces platelet apoptosis and clearance through PDE3A-mediated PKA inhibition. Activation of PKA rescues E2-induced thrombocytopenia in mice. Thus, our study reveals a pathogenesis of E2-related CTP and suggests promising therapeutic strategies for the disease. [ABSTRACT FROM AUTHOR]

A new dynamical model is built to describe the process of microwave window breakdown at the vacuum/dielectric interface. In this model, the effects of gas desorption and gas diffusion on breakdown are first taken into account. The evolution of the density of electrons and the neutral gas is analyzed. Particle-in-cell simulations are employed to validate this model, and the agreements of comparisons are favorable. The results show that the density of neutral gas decreases exponentially with the distance away from the dielectric surface. It is concluded that the gas diffusion is the main factor in the density reduction of neutral gas. With the influence of gas ionization, the number of electrons striking the dielectric surface increases. As a result, the gas pressure above the dielectric surface increases rapidly. In addition, the discharge formation time tc of microwave window breakdown decreases exponentially with the gas desorption rate. Besides, tc decreases with the energy of the first crossover point of the secondary electron emission curve when the strength of microwave electric field Erf is small. This dynamical model provides a solution to designing the microwave window. [ABSTRACT FROM AUTHOR]

Secondary electron emission (SEE) is a fundamental phenomenon of particle/surface interaction, and the multipactor effect induced by SEE can result in disastrous impacts on the performance of microwave devices. To suppress the SEE-induced multipactor, an Ni (111) surface covered with a monolayer of graphene was proposed and studied theoretically via the density functional theory (DFT) method. The calculation results indicated that redistribution of the electron density at the graphene/Ni (111) interface led to variations in the work function and the probability of SEE. To validate the theoretical results, experiments were performed to analyze secondary electron yield (SEY). The measurements showed a significant decrease in the SEY on an Ni (111) surface covered with a monolayer of graphene, accompanied by a decrease in the work function, which is consistent with the statistical evidence of a strong correlation between the work function and SEY of metals. A discussion was given on explaining the experimental phenomenon using theoretical calculation results, where the empty orbitals lead to an electron trapping effect, thereby reducing SEY. [ABSTRACT FROM AUTHOR]

Vacuum surface flashover is the main factor limiting the development of pulsed power system. In this work, a quantitative dynamical model is built to investigate the vacuum surface flashover from field emission to secondary electron emission avalanche (SEEA). The results show that positive charges accumulating on the dielectric surface caused by field emission electrons play a dominant role when the normal electric field on the dielectric surface Edc is small. The growth of the number of positive surface charges exponentially decreases with the distance from the cathode triple junction (CTJ). With the increase in the density of positive surface charges, the growth of positive surface charges mainly depends on the secondary electrons cascade. As a result, the saturation state of Edc will first occur on the dielectric surface at a distance hundreds of micrometers from the CTJ. In addition, the effect of dielectric permittivity on positive surface charges is considered. The density of positive surface charges equals (1+εr) ε0Edc rather than 2ε0Edc. Particle-in-cell simulations are employed to verify the correctness of the theory model, and the agreement of comparisons is favorable. Furthermore, the space charge effect is discussed. When SEEA reaches saturation, electrons can significantly change the spatial distribution of the electric field. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to explore the expression of hnRNP K in cervical carcinogenesis and to investigate the regulatory role of hnRNP K on HPV16 oncogene expression as well as biological changes in cervical cancer cells. Methods: In total 1042 subjects, including 573 with the normal cervix and 469 with different grades of cervical lesions were enrolled in this study to explore the association between hnRNP K and HPV16 oncogene expression in cervical carcinogenesis. Additionally, the Gene Omnibus (GEO) database was used to analyze hnRNP K mRNA expression in cervical cancerization. Meanwhile, the effects of hnRNP K on cell biological functions and HPV16 oncogene expression were investigated in Siha cells. Moreover, Function analyses were conducted using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) databases after ChIP-seq. Results: hnRNP K was highly expressed in cervical cancer and precancerous lesions, and positively correlated with HPV16 E6, but negatively correlated with HPV16 E2 and HPV16 E2/E6 ratio. hnRNP K induced cell proliferation, inhibited apoptosis and caused cell cycle arrest in the S phase, and particularly increased HPV16 E6 protein expression. Conclusion: This study revealed that hnRNP K overexpression has important warning significance for the malignant transformation of cervical lesions, and could be used as a potential therapeutic target for inhibiting the carcinogenicity of HPV16 and prevention of cervical carcinogenesis. [ABSTRACT FROM AUTHOR]

Pre-ionization caused by runaway electrons is an important mechanism for negative streamer development. The aim of this paper is to investigate the runaway criteria and overvoltage threshold of electrons at the initial stage of streamer development in air, with the self-developed 3D particle-in-cell with Monte Carlo Collision code. First, numerical simulations are performed with fixed number of electrons to study the runaway criteria in nonrelativistic cases. This method takes the stochastic fluctuations of collisions into account and solves the major shortcomings of theoretical approach. The simulated critical electric field is less than that of the theoretical approach, and the amplitude of the difference increases with electron energy, due to the "tunneling effect" caused by the stochastic fluctuations of collisions. Then, simulations of negative streamers at various applied voltages are performed to investigate the overvoltage threshold. A more intuitive method, searching energetic electrons in front of the negative streamer head, which corresponds to the nature of runaway electrons, is applied to determine the generation of runaway electrons. Electrons that escaped a certain distance ahead of the streamer can be observed at 30 kV. Thus, the overvoltage threshold for runaway electrons can be roughly estimated as 3.3 in our simulations, which is about three times less than the previously published one. At last, with the redefined overvoltage threshold, the figure of regions of breakdown development for various mechanisms depending upon the overvoltage in air is updated. [ABSTRACT FROM AUTHOR]

In this paper, the influence of external terahertz electromagnetic fields with different frequencies of 4 THz, 10 THz, 15 THz, and 20 THz on the permeability of the Kv1.2 voltage-gated potassium ion channel on the nerve cell membrane was studied using the combined model of the "Constant Electric Field-Ion Imbalance" method by molecular dynamics. We found that although the applied terahertz electric field does not produce strong resonance with the –C=O groups of the conservative sequence T-V-G-Y-G amino acid residue of the selective filter (SF) of the channel, it would affect the stability of the electrostatic bond between potassium ions and the carbonyl group of T-V-G-Y-G of SF, and it would affect the stability of the hydrogen bond between water molecules and oxygen atoms of the hydroxyl group of the 374THR side chain at the SF entrance, changing the potential and occupied states of ions in the SF and the occurrence probability of the permeation mode of ions and resulting in the change in the permeability of the channel. Compared with no external electric field, when the external electric field with 15 THz frequency is applied, the lifetime of the hydrogen bond is reduced by 29%, the probability of the "soft knock on" mode is decreased by 46.9%, and the ion flux of the channel is activated by 67.7%. Our research results support the view that compared to "direct knock-on", "soft knock-on" is a slower permeation mode. [ABSTRACT FROM AUTHOR]

Plasmonic devices work at visible and near-infrared frequencies, where a large number of bound electrons (polarization) in metals are excited. However, the existing particle-in-cell (PIC) software cannot take into account these bound electrons. In this paper, a new PIC simulation method is developed to study plasmonic devices, which has the ability to model both free electrons and bound electrons in metals. In this study, surface plasmon polaritons (SPPs) are excited by depositing excess electrons at one end of the metal film of thickness 140 nm (surrounded by air), thus initiating nonequilibrium in the electron density to start the oscillations. The spectrum, mode size, and propagation length of SPPs are calculated to confirm the electrical excitation of SPPs and characterize their properties. The excited SPPs are of a broad range of frequencies. Unlike SPPs excited by inelastic electron tunneling, the spectrum of SPPs excited in this way is not determined by e V b i a s but only by the properties of metals and dielectrics, and therefore the excited SPPs are intrinsic. The mode sizes of the intrinsic SPPs in the Ag–air geometry are 30 nm in Ag and 120 nm in air. The propagation length is ∼730 nm. The excited SPPs are converted into radiation modes by a sub-wavelength slit etched on the back side of the film to enable the detection of the radiation modes. [ABSTRACT FROM AUTHOR]

The high power microwave window breakdown characteristics of N2–SF6 mixtures are investigated with 3D particle-in-cell and Monte Carlo collision simulation. The space and density distributions of electrons and ions are obtained. The results show that the threshold of breakdown increases with the ratio of SF6 when E/P is large. However, when E/P is small, the threshold of breakdown in 70% of SF6 and 30% of N2 is greater than that of pure SF6. This phenomenon is also observed in experiments. The theory analyses show that the energy loss of electrons is mainly caused by excitation collisions with N2 when the average energy of electrons Te is less than 6 eV and is dominated by excitation and ionization collisions with SF6 when Te is greater than 6 eV. When E/P is small, the proportion of low energy electrons is large and Te increases with the ratio of SF6. Therefore, the effective ionization rate first decreases and then increases as the ratio of SF6 increases. Thus, the optimal ratio for improving the insulation properties is 60%–80% SF6 when E/P is small. When E/P is large, the proportion of high energy electrons increases. Therefore, the effective ionization rate and density of electrons decrease as the ratio of SF6 increases. The maximum threshold of breakdown occurs when the ratio of SF6 is 100%. [ABSTRACT FROM AUTHOR]

The formation and evolution of the cathode plasma in small-gap magnetically insulated transmission lines (MITLs) may lead to enormous current loss and even gap closure. This issue has been investigated through particle-in-cell/Monte Carlo collision simulations. Based on gas desorption from the cathode, the plasma is formed at the cathode when the emitted electrons collide with the desorbed gas contaminants. The expansion velocity and the electron and ion density distributions of the cathode plasma were analyzed. Rapid expansion of the plasma occurs when plasma instability increases due to a transverse magnetic mode in the MITL. Factors affecting the expansion velocity such as voltage amplitude and rate of gas desorption were examined. The simulation results indicated that a relatively high desorption rate of neutral gas resulted in a higher expansion velocity for the cathode plasma. This work extends our knowledge and understanding of cathode plasma dynamics in high-current MITLs. [ABSTRACT FROM AUTHOR]

In sub-THz communication systems, compact, high-power, tunable radiation sources are required. Backward wave oscillators (BWO) have been practical devices for THz communication, but the maximum output power can be several times more than the minimum in the operation frequency range. To obtain the low peak-to-average ratio (LPAR) of the maximum power to the average power, the local maximum output power in the operation frequency range is first found theoretically and verified by particle-in-cell simulation. The LPAR 850 GHz BWO is then proposed. It applies a corrugated rectangular waveguide slow-wave structure, whose geometrical parameters are optimized using a multi-constrained optimization method. The optimized BWO operating in the frequency range from 790 to 882 GHz is simulated by the CST Particle Studio. The device can deliver at least 0.58 W with a LPAR of 1.08 when the conductivity of the slow-wave structure is 5.96 × 107 S/m. For a smaller conductivity of 3 × 107 S/m, the BWO can deliver at least 0.4 W with a LPAR of 1.13. [ABSTRACT FROM AUTHOR]

A novel large-area (20-inch) photomultiplier tube based on microchannel plate (MCP-PMTs) is proposed for the Jiangmen Underground Neutrino Observatory (JUNO) experiment. Its photoelectron collection efficiency C e is limited by the MCP open area fraction ( A open ). This efficiency is studied as a function of the angular ( θ ), energy ( E ) distributions of electrons in the input charge cloud and the potential difference ( U ) between the PMT photocathode and the MCP input surface, considering secondary electron emission from the MCP input electrode. In CST Studio Suite, Finite Integral Technique and Monte Carlo method are combined to investigate the dependence of C e on θ , E and U . Results predict that C e can exceed A open , and are applied to optimize the structure and operational parameters of the 20-inch MCP-PMT prototype. C e of the optimized MCP-PMT is expected to reach 81.2%. Finally, the reduction of the penetration depth of the MCP input electrode layer and the deposition of a high secondary electron yield material on the MCP are proposed to further optimize C e . [ABSTRACT FROM AUTHOR]

Ion transport molecules are involved in many physiological and pathological processes and are considered potential targets for cancer treatment. In the large family of ion transport molecules, potassium (K) ion channels, as surface-expressed proteins, show the highest variability and most frequent expression changes in many tumor types. The key to exploring the permeation of K+ through potassium channels lies in the conserved sequence TVGYG, which is common in the selectivity filter (SF) region of all potassium channels. We found that the K+ flux significantly increased with the help of a specific frequency terahertz electromagnetic wave (51.87 THz) in the KcsA channel using a molecular dynamics combined model through the combined simulation of the constant electric field method and ion imbalance method. This frequency has the strongest absorption peak in the infrared spectrum of -C=O groups in the SF region. With the applied electric field of 51.87 THz, the Y78 residue at the S1 site of the SF has a smaller vibration amplitude and a more stable structure, which enables the K+ to bind closely with the carbonyl oxygen atoms in the SF and realize ion conduction in a more efficient direct Coulomb knock-on. [ABSTRACT FROM AUTHOR]

Negative and positive ions crossing the anode-cathode gap of a magnetically insulated transmission line (MITL) can cause non-negligible current loss and energy deposition on the electrodes, which may lead to the formation of anode plasma and the growth of cathode plasma. Furthermore, gap closure could occur due to the expansion of cathode plasma and anode plasma. In this paper, a model for magnetic insulation of both negative ion flow and positive ion flow is developed. The operating voltage V of the MITL is expressed as a function of the total current I0 and the boundary current Ib. The total current and the boundary current of the MITL are derived at saturated and self-limited flows, respectively. In addition, particle-in-cell simulations are implemented for the validation of the theoretical model. The thickness and density of the magnetically insulated ion layers are analyzed, and an empirical expression for space charge factor g is obtained through simulation results. This work extends the understanding of magnetically insulated ion flow in MITLs. [ABSTRACT FROM AUTHOR]

The curved structure of a coaxial magnetically insulated transmission line (MITL) causes it to generate a nonuniform azimuthal magnetic field, which can disturb the electron flow and lead to a higher current loss when compared with a straight MITL. In this paper, the current loss mechanism and nonuniformity of the azimuthal magnetic field inherent to curved MITLs are investigated using theoretical analysis and particle-in-cell simulations. Results show that the critical current for magnetic insulation of the curved MITL increases with nonuniformity of the azimuthal magnetic field. The magnitude of the azimuthal magnetic field of the curved MITL can be described by a cosine distribution, lower in the outer region and higher in the inner region of the curved MITL. Nonuniformity of the azimuthal magnetic field decreases as electron current increases. Finally, an empirical expression relating to the structural parameters of curved MITLs is obtained for nonuniformity of the azimuthal magnetic field, which can be used to estimate the critical current for magnetic insulation in curved MITLs. This work extends the understanding of magnetic insulation in curved coaxial transmission lines. [ABSTRACT FROM AUTHOR]

Postoperative cognitive dysfunction (POCD) is a prevalent disorder after anaesthesia in the elderly patients. Roflumilast (RF), a phosphodiesterase 4 (PDE‐4) inhibitor, could improve cognition with no side effects. Here, we sought to explore the efficacy of RF in the improvement of cognitive dysfunction caused by sevoflurane (Sev). Sprague–Dawley rats were anaesthetized, and the hippocampal neurons were treated with Sev to develop in vivo and in vitro POCD models, followed by RF administration. The mechanism of the PKA‐CREB and MEK/ERK pathways in the pathogenesis of POCD was explored. Sev impaired the cognitive functions of rats, significantly reduced cyclic adenosine monophosphate (cAMP) concentrations and blocked the PKA‐CREB and MEK/ERK pathways. Moreover, the Sev‐treated rats and neurons exhibited enhanced apoptosis and reactive oxygen species (ROS). After treatment with RF, rats had better learning and memory function, and the activity of neurons in hippocampus and cortex was improved. Loss‐of‐function assay indicated that PKA‐CREB and MEK/ERK signalling impairment reduced cAMP levels and promoted apoptosis and ROS in rat hippocampus and neurons. Generally, RF promotes neuronal activity in rats after Sev treatment by maintaining cAMP levels and sustaining the activation of PKA‐CREB and MEK/ERK pathways. This might offer novel sights for POCD therapy. [ABSTRACT FROM AUTHOR]

Surface roughening is an important material surface treatment technique, and it is particularly useful for use in secondary electron yield (SEY) suppression on metal surfaces. Porous structures produced via roughening on coatings have been confirmed to reduce SEY, but the regulation strategy and the influence of process parameters both remain unclear in the practical fabrication of effective porous structures. In this paper, the effect of the surface morphology of porous coatings on the SEY of aluminum alloy substrates was studied. Surface characterization and SEY measurements were carried out for samples with a specific process technique on their surfaces. An exponential fitting model of the correlation between surface roughness and the peak values of SEY curves, δ m , was summarized. Furthermore, an implementation strategy to enable low surface SEY was achieved from the analysis of the effect of process parameters on surface morphology formation. This work will aid our understanding of the effect of the irregular surface morphology of porous coatings on SEY, thereby revealing low-cost access to the realization of an easy-to-scale process that enables low SEY. [ABSTRACT FROM AUTHOR]

The breakdown characteristics of C4F7N/CO2 mixtures under dc condition are investigated with a particle-in-cell method. The processes of elastic, excitation, ionization, and attachment collisions are all considered. The elastic cross section of electron scattering from C4F7N is modeled through quantum mechanical spherical complex optical potential formalism. Based on the cross-sectional data, the dielectric strength of pure C4F7N is studied. The threshold of breakdown is in good agreement with the experiment. Besides, the dielectric strength of C4F7N/CO2 mixtures is also obtained. The threshold of breakdown in 80% C4F7N and 20% CO2 is larger than that of pure C4F7N when the gas pressure is larger than 1300 torr. The results show that the energy loss of electrons is mainly caused by excitation collision with CO2 when the energy of electrons ${T}_{e}$ is smaller than 5.5 eV. When ${E}/{P}$ is small, the proportion of low-energy electrons is large and ${T}_{e}$ increases with the ratio of C4F7N. Therefore, the effective ionization rate first decreases and then increases as the ratio of C4F7N increases. [ABSTRACT FROM AUTHOR]

With the introduction of the gas diffusion model, the surface flashover at the insulator–vacuum interface perpendicular to electrodes is simulated with the particle-in-cell method. The distributions of density of electrons, ions, and neutral gas molecules are obtained, which is consistent with images diagnosed in the experiment. The gas pressure at the dielectric surface near electrodes is much higher than it is at other locations. Furthermore, the processes of vacuum surface flashover for angled dielectric insulators are analyzed. The results show that negative charges will accumulate on the dielectric surface when the negative angle is large. The electric field produced by negative charges weakens the normal electric field and emission current on the cathode triple junction. Moreover, the process of secondary electron emission is completely suppressed when the negative angle is large. With the development of gas desorption, the breakdown will evolve from field emission into gas ionization. Therefore, when the angle is negative, the threshold of surface flashover first decreases then increases with the angle, which is in good agreement with laws obtained in experiments. This study can provide a deep understanding to the vacuum surface flashover. [ABSTRACT FROM AUTHOR]

This paper reports on the use of a novel all-porous-silicon configuration consisting of a surface grating and a highreflectivity quarter-wave stack, arranged as both an all-poroussilicon grating diffractive device, and a highly sensitive and inexpensive biosensor. The diffraction efficiency of the top surface grating in this structure can be considerably improved for biosensing. Moreover, a porous-silicon high-reflectivity multilayer can not only prevent the signal energy from radiating to the substrate, but also increase the internal surface area of the sensing platform for detecting more probing molecules. When 3-aminopropyltriethoxysilane (APTES) was employed as a probing molecule, the sensitivity of the proposed structure increased up to 1 order higher than the porous-silicon diffraction-grating biosensors without a high-reflectivity quarter-wave stack. It has been shown by experimentation that before and after the APTES, -3-order diffraction efficiency changes from 1.30×10-3 to 1.25×10-4. Excellent agreement is achieved between the experimental results and simulations based on the rigorous coupled-wave analysis. [ABSTRACT FROM AUTHOR]

Background: Gallbladder carcinoma (GBC) is a relatively rare but highly aggressive cancer with late clinical detection and a poor prognosis. However, the lack of models with features consistent with human gallbladder tumours has hindered progress in pathogenic mechanisms and therapies. Methods: We established organoid lines derived from human GBC as well as normal gallbladder and benign gallbladder adenoma (GBA) tissues. The histopathology signatures of organoid cultures were identified by H&E staining, immunohistochemistry and immunofluorescence. The genetic and transcriptional features of organoids were analysed by whole‐exome sequencing and RNA sequencing. A set of compounds targeting the most active signalling pathways in GBCs were screened for their ability to suppress GBC organoids. The antitumour effects of candidate compounds, CUDC‐101 and CUDC‐907, were evaluated in vitro and in vivo. Results: The established organoids were cultured stably for more than 6 months and closely recapitulated the histopathology, genetic and transcriptional features, and intratumour heterogeneity of the primary tissues at the single‐cell level. Notably, expression profiling analysis of the organoids revealed a set of genes that varied across the three subtypes and thus may participate in the malignant progression of gallbladder diseases. More importantly, we found that the dual PI3K/HDAC inhibitor CUDC‐907 significantly restrained the growth of various GBC organoids with minimal toxicity to normal gallbladder organoids. Conclusions: Patient‐derived organoids are potentially a useful platform to explore molecular pathogenesis of gallbladder tumours and discover personalized drugs. [ABSTRACT FROM AUTHOR]

We present an S-band high-power microwave (HPM) oscillator based on crossed-elliptical metamaterial (MTM) rings in a circular waveguide and powered by a high-power electron beam. Particle-in-cell (PIC) simulations demonstrate that when an output horn antenna of radius of 200 mm is used, an output power of 443 MW of a backward wave TE41 mode below its cutoff frequency at 2.80 GHz can be generated using a pulsed electron beam with a voltage of 990 kV and a current of 1.736 kA in a 1.8-T solenoidal magnetic field, corresponding to an electronic efficiency up to 26%. Meanwhile, another degenerate frequency of 2.80 GHz of a forward wave in the TM01 mode with an output power of 9 MW is also observed. When an output horn antenna of radius 150 mm is used, this crossed-elliptical MTM oscillator operates mainly in a forward TM01 mode at 2.80 GHz with an output power of 325 MW at an electronic efficiency of 19%, and at the same time, a backward wave TE41 mode below its cutoff frequency of 2.80 GHz with an output power of 8 MW can be observed. Simulations indicate that this slow-wave structure (SWS) consisting of a periodically crossed-elliptical MTM loaded circular waveguide can support degenerate mode operation. This result suggests that this configuration is favorable for mode switching and this work seeks to design a compact HPM source. [ABSTRACT FROM AUTHOR]

Abstract: A simple broadband T-shaped waveguide branch in photonic crystals is constructed only by introducing three dielectric rods into the waveguide channels near branch region. Numerical results indicate that the bandwidth of high transmission (the total transmittance is larger than 95%) is over 415nm centered at 1550nm. Owing to its simple structure and broad enough bandwidth, this waveguide branch is expected to be applied to highly dense photonic integrated circuits. [Copyright &y& Elsevier]

Abstract: A planar diode with finite-radius emitter is studied with particle-in-cell simulations to extend the classical one-dimensional (1D) Child–Langmuir law to two-dimensions. It is found that the 2D space–charge-limited current density in units of the classical 1D value follows a monotonically decreasing function of the dimensionless ratio of emitter radius (R) to gap separation (D), and the function can be extended to relativistic regime without significant modification. It is also verified that Lau''s analytical prediction of the 2D Child–Langmuir law is in better agreement with the simulation results in comparison with Rokhlenko''s. [Copyright &y& Elsevier]

This study aims to investigate the effect of the pretreatment of S-ketamine on postoperative depression (POD) for breast cancer patients with mild/moderate depression. The present randomized, double-blinded controlled trial included 303 breast cancer patients with mild/moderate depression from June 2017 to June 2018. All patients were randomly divided into three groups: (1) control group, patients treated with normal saline; (2) racemic ketamine group, patients treated with racemic ketamine; (3) S-ketamine group, patients treated with S-ketamine. Operation time, blood loss and hospital stay and complications were recorded. The Visual Analog Scale (VAS) score was recorded, and the Hamilton Rating Scale for Depression (HAMD-17) scores, serum brain-derived neurotrophic factor (BDNF) and 5-hydroxytryptamine (5-HT) were measured at three days, one week, one month and three months after surgery. No significant difference was found in operation time, bleeding volume and complication rate. In both groups, the VAS scores at one day and three days after surgery were significantly lower. The HAMD-17 scores were significantly lower, and the serum levels of both BDNF and 5-HT were remarkably higher at three days, one week and one month after surgery. Meanwhile, the HAMD-17 scores were remarkably lower, while the serum levels of BDNF and 5-HT were remarkably higher in the S-ketamine group. The BDNF and 5-HT levels were negatively correlated with the HAMD-17 score. S-ketamine is more effective for reducing POD for breast cancer patients. [ABSTRACT FROM AUTHOR]

A microcavity array device decorated by silicon nanowires (SiNWs) is fabricated and the discharge property improvement is investigated. The array device can be operated stably from several kPa to atmospheric pressure of argon, powered by a 20 kHz bipolar nanosecond pulse source. Profiting by electron emission from SiNWs, the microplasma discharge dynamics and emission properties are significantly enhanced. Experimental results manifest that the instantaneous total current of the device decorated by SiNWs is up to ∼20% higher than that of the device without SiNWs and the mean current is increased by ∼12.5% compared with the conventional device (without SiNWs), and the ignition voltage decreased by ∼24%. The setup time is less than 90 ns before the device is fully ignited, and emission intensity enhanced by over 60% compared with the conventional plain surface device. Moreover, calculated by Lissajous figures, the discharge power of proposed device is higher than that of the traditional device with increment of ∼26%, and the impact of SiNWs on microdischarge processes is analyzed. The mechanism of the microplasma property enhancement is discussed through introducing the electric field enhancement effect at SiNWs cap and initial seed electrons emitted from SiNWs. This work combines the characteristic advantages of SiNWs with microcavity gas discharge to achieve the performance improvement of microplasma, and the results reported here has profound impacts on improving microplasma discharge properties and implies potential significance in promoting the performance of plasma applications. [ABSTRACT FROM AUTHOR]

The effects of introducing some amount of KNO 3 into the raw materials on preparation of fluorophosphate glass are investigated in terms of UV–vis transmittance, absorption coefficient and change of refractive index. As the content of KNO 3 reaches 50%, the UV absorption coefficient of the optimized fluorophosphate glass reaches the minimum due to absence of microcrystals in the produced glass. The Schott's Sellmeier dispersion formula and Ghosh's two-polar wavelength-dependent Sellmeier equation were both used to calculate dispersion constants of the optimized fluorophosphate glass. The optimized fluorophosphate glass maintains special characteristics of negative temperature coefficient of refractive index and near-zero thermo-optical coefficient. The lower absorption both in UV and near-infrared (NIR) helps to improve its laser-induced damage resistance. The athermal fluorophosphate glass shows great potential for compensation of thermal-induced distortion in high-power solid-state lasers and high-resolution optical systems. • Introduction of KNO 3 into the investigated fluorophosphate glass batch helps to prevent formation of microcrystals and thus reduced the scattering loss of the prepared glass, resulting in higher UV transmission and improved resistance to 1 laser irradiation. The optimized fluorophosphate glass has negative thermo-optical coefficient and low near-infrared loss, which show potential as thermal distortion compensation in high-power near-infrared lasers (for example 1 μm solid lasers and 1.3 μm oxy-iodine laser) and high-resolution optical systems. [ABSTRACT FROM AUTHOR]

Multipactor statistical modeling is one vital theoretical treatment for both multipactor mechanism analysis and threshold prediction, but its practical application is still severely constrained due to its obstinate dependence on the electron trajectory formula. Hence, this paper proposes a novel and general implementation method to improve the feasibility and accuracy of one-dimensional (1D) multipactor statistical modeling, where the joint probability density function is constructed through numerically tracking electron trajectories. On that basis, better agreement with the experimental results is obtained for multipactor threshold predictions of coaxial lines than the classical statistical calculations adopting the approximate electron trajectory formula. Besides the accuracy improvement, this approach also makes multipactor statistical modeling regardless of the field complexity and thus applicable to investigating any one-dimensional multipactor problem in microwave devices. This research work can further popularize the application of multipactor statistical modeling and provide one highly sought treatment with both good accuracy and efficiency for the optimal design of multipactor-free microwave devices, thus further promoting the development of space communication capability. [ABSTRACT FROM AUTHOR]