Frequency Tunability and Slow-Wave Characteristics of a High-Efficiency Ridged MILO

A high-efficiency ridged magnetically insulated transmission line oscillator (RMILO) is proposed and investigated theoretically and numerically in this paper. In the RMILO, ridge-disk vanes are introduced to enhance the power efficiency. Theoretical investigation shows that the ridge-disk can enhance the coupling impedance of the slow-wave structure (SWS), and so enhance the power efficiency. Moreover, the ridge has a weak influence on frequency, so, it influences little on the tunability of the MILO. In simulation, when the applied voltage is increased to 807 kV, the RMILO can get the 3 dB tunable frequency range with 7.6 - 13.9 GHz and the 3 dB tuning bandwidth with 58.6% which has an increase of 27.6% compared with the conventional MILO. So, the tuning performance of the RMILO is more superior. Besides, the RMILO gets the maximum output power of 7.1 GW, the corresponding power efficiency is 22.6% and the frequency is 1.400 GHz. Furthermore, when the applied voltage is increased to 807 kV, high-power microwave with a power of 13.5 GW, frequency of 1.400 GHz, and ef?ciency of 24.5% is generated, which has an increase of 20.2% compared with the conventional MILO. The simulation results con?rm the ones predicted by theoretical analysis.

Nitrogen and atomic Fe dual-doped porous carbon nanocubes as superior electrocatalysts for acidic H2-O_(2) PEMFC and alkaline Zn-air battery

Air cathodes with high electrocatalytic activity are vital for developing H2/O_(2) proton exchange membrane fuel cells(PEMFC)and Zn-air batteries.However,the state-of-the-art air cathodes suffer from either limited catalytic activity or high cost,which thus hinder their applications.Herein,we designed ZIF-8 derived nitrogen and atomic iron dual-doped porous carbon nanocubes as high-quality catalysts for ORR,through a novel gas-doping approach.The porous carbon nanocubic architecture and abundant Fe-Nxactive species endow ZIF-8 derived single atomic iron catalyst(PCN-A@Fe SA)with superior catalytic activity,and surpass Pt/C and a majority of the reported catalysts.Both XAS and DFT calculations suggest that Fe2+N4 moieties are the main active centers that are favorable for oxygen affinity and OH*intermediate desorption,which can result in promising catalytic performance.Most importantly,PCNA@Fe SA can achieve power density of 514 m W cm^(-2) as cathodic catalyst in a PEMFC and discharge peak power density of 185 m W cm^(-2) in an alkaline Zn-air battery.The outstanding performance is derived from both the high specific surface area and high-density of iron single atom in nitrogen doped nanocubic carbon matrix.

Observation of the effect of one-to-one education on high-risk cases of diabetic foot

BACKGROUND Diabetes is a common chronic disease,and its global incidence is on the rise.The disease is directly attributed to insufficient insulin efficacy/secretion,and patients are often accompanied by multiple complications.Diabetic foot is one of the most common complications of diabetes.Diabetic feet have ulcers and infections,which can eventually lead to amputation.Basic nursing care,such as lowering blood pressure and preventing foot skin infections in clinical nursing work,has positive significance for the prevention and control of diabetic feet.AIM To explore the positive significance of one-to-one education in high-risk cases of diabetic foot.METHODS This observation included 98 high-risk cases of diabetic foot in our hospital during the period from August 2017 to October 2019,and these patients were randomly divided into the basic nursing group and the one-to-one education group with 49 patients per group.The basic nursing group only received routine basic nursing,while the one-to-one education group gave patients one-to-one education on the basis of basic nursing.After nursing,the self-care ability and compliance behavior of the two groups were evaluated and compared between these two groups.The knowledge mastery of the patient and the satisfaction of nursing were accounted.RESULTS The assessment results of patients(self-care responsibility,self-care skills,selfconcept and self-care knowledge)were significantly higher in the one-to-one education group than in the basic nursing group.The scores of compliance behaviors(foot bathing,shoes and socks selection,sports health care)in the oneto-one education group were significantly higher than those in the basic nursing group.Patients in the one-to-one education group had a significantly higher level of knowledge mastery and satisfaction of nursing than the basic nursing group.CONCLUSION One-to-one education for high-risk cases of diabetic foot is helpful to improve the cognition and self-care ability of patients with diabetic foot,to ensure that patients follow the doctor’s advice of self-care and to improve their nursing satisfaction.

Highly efficient H-bonding charge-transfer complex for microsupercapacitors under extreme conditions of low temperatures

Owing to sluggish ionic mobility at low temperatures, supercapacitors, as well as other energy-storage devices, always suffer from severe capacity decay and even failure under extreme low-temperature circumstances. Solar-thermal-enabled self-heating promises an attractive approach to overcome this issue.Here, we report a unique H-bonding charge-transfer complex with a high photothermal conversion efficiency of 79.5% at 405 nm based on chloranilic acid and albendazole. Integrated with a microsupercapacitor, the chloranilic acid-albendazole complex(CAC) film prompts an apparent temperature increase of 22.7 °C under 1 sun illumination at-32.6 °C, effectively elevating the working temperature of devices.As a result, the rate capability of the microsupercapacitor has been significantly improved with a 17-fold increase in capacitance at a current density of 60 μA cm^(-2), leading to outstanding low-temperature performances. Importantly, the integrated device is capable of working at a low temperature of-30 °C in the open air, which demonstrates the potential of CAC in practical applications for low-temperature ultracapacitive energy-storage devices.

Tunable circularly-polarized turnstile-junction mode converter for high-power microwave applications

Frequency tunability has become a subject of concern in the field of high-power microwave（HPM） source research.However, little information about the corresponding mode converter is available. A tunable circularly-polarized turnstilejunction mode converter（TCTMC） for high-power microwave applications is presented in this paper. The input coaxial TEM mode is transformed into TE（10） mode with different phase delays in four rectangular waveguides and then converted into a circularly-polarized TE（11） circular waveguide mode. Besides, the rods are added to reduce or even eliminate the reflection. The innovations in this study are as follows. The tunning mechanism is added to the mode converter, which can change the effective length of rectangular waveguide and the distance between the rods installed upstream and the closest edge of the rectangular waveguide, thus improving the conversion efficiency and bandwidth. The conversion efficiency of TCTMC can reach above 98% over the frequency range of 1.42 GHz–2.29 GHz, and the frequency tunning bandwidth is about 47%. Significantly, TCTMC can obtain continuous high conversion efficiency of different frequency points with the change of tuning mechanism.

Endothelial phosphodiesterase 4B inactivation ameliorates endothelial-to-mesenchymal transition and pulmonary hypertension

Pulmonary hypertension (PH) is a fatal disorder characterized by pulmonary vascular remodeling and obstruction. The phosphodiesterase 4 (PDE4) family hydrolyzes cyclic AMP (cAMP) and is comprised of four subtypes (PDE4A–D). Previous studies have shown the beneficial effects of pan-PDE4 inhibitors in rodent PH;however, this class of drugs is associated with side effects owing to the broad inhibition of all four PDE4 isozymes. Here, we demonstrate that PDE4B is the predominant PDE isozyme in lungs and that it was upregulated in rodent and human PH lung tissues. We also confirmed that PDE4B is mainly expressed in the lung endothelial cells (ECs). Evaluation of PH in Pde4b wild type and knockout mice confirmed that Pde4b is important for the vascular remodeling associated with PH. In vivo EC lineage tracing demonstrated that Pde4b induces PH development by driving endothelial-to-mesenchymal transition (EndMT), and mechanistic studies showed that Pde4b regulates EndMT by antagonizing the cAMP-dependent PKA–CREB–BMPRII axis. Finally, treating PH rats with a PDE4B-specific inhibitor validated that PDE4B inhibition has a significant pharmacological effect in the alleviation of PH. Collectively, our findings indicate a critical role for PDE4B in EndMT and PH, prompting further studies of PDE4B-specific inhibitors as a therapeutic strategy for PH.

Pneumoconiosis: current status and future prospects

Pneumoconiosis refers to a spectrum of pulmonary diseases caused by inhalation of mineral dust,usually as the result of certain occupations.The main pathological features include chronic pulmonary inflammation and progressive pulmonary fibrosis,which can eventually lead to death caused by respiratory and/or heart failure.Pneumoconiosis is widespread globally,seriously threatening global public health.Its high incidence and mortality lie in improper occupational protection,and in the lack of early diagnostic methods and effective treatments.This article reviews the epidemiology,safeguard procedures,diagnosis,and treatment of pneumoconiosis,and summarizes recent research advances and future research prospects.

SARS-Coronavirus-2 Nsp13 Possesses NTPase and RNA Helicase Activities That Can Be Inhibited by Bismuth Salts

The ongoing outbreak of Coronavirus Disease 2019(COVID-19)has become a global public health emergency.SARScoronavirus-2(SARS-CoV-2),the causative pathogen of COVID-19,is a positive-sense single-stranded RNA virus belonging to the family Coronaviridae.For RNA viruses,virus-encoded RNA helicases have long been recognized to play pivotal roles during viral life cycles by facilitating the correct folding and replication of viral RNAs.Here,our studies show that SARS-CoV-2-encoded nonstructural protein 13(nsp13)possesses the nucleoside triphosphate hydrolase(NTPase)and RNA helicase activities that can hydrolyze all types of NTPs and unwind RNA helices dependently of the presence of NTP,and further characterize the biochemical characteristics of these two enzymatic activities associated with SARS-CoV-2 nsp13.Moreover,we found that some bismuth salts could effectively inhibit both the NTPase and RNA helicase activities of SARS-CoV-2 nsp13 in a dose-dependent manner.Thus,our findings demonstrate the NTPase and helicase activities of SARS-CoV-2 nsp13,which may play an important role in SARS-CoV-2 replication and serve as a target for antivirals.

The ORF3a protein of SARS-CoV-2 induces apoptosis in cells

Severe acute respiratory syndrome coronavirus-2(SARS-CoV-2)has caused the ongoing pandemic of Coronavirus Disease 2019.SARS-CoV-2 belongs to the genus Betacoronavirus of the Coronaviridae family,which includes SARS-CoV and Middle East respiratory syndrome coronavirus.1,2 Coronavirus-encoded accessory proteins play critical roles in virus–host interactions and the modulation of host immune responses,thereby contributing to coronaviral pathogenicity via different strategies.3 However,the functions of SARS-CoV-2-encoded accessory proteins are not well understood.Apoptosis is a predominant type of programmed cell death,and has been recognized as an important host antiviral defense mechanism that controls viral infection and regulates the inflammatory response.4,5 Previous studies have reported that the SARS-CoV-encoded accessory protein ORF3a can induce apoptosis in cells,6,7 leading to the question of whether SARS-CoV-2 ORF3a also has pro-apoptotic activity.Here,we investigated the potential apoptosis-inducing activity of SARS-CoV-2 ORF3a in different cell lines and compared the pro-apoptotic activities of SARS-CoV-2 ORF3a with those of SARS-CoV ORF3a using the same system.

Cytokines and inflammation in adipogenesis:an updated review

The biological relevance of cytokines is known for more than 20 years.Evidence suggests that adipogenesis is one of the biological events involved in the regulation of cytokines,and pro-inflammatory cytokines (e.g.,TNFα and IL-1β)inhibit adipogenesis through various pathways.This inhibitory effect can constrain the hyperplastic expandability of adipose tissues.Meanwhile,chronic low-grade inflammation is commonly observed in obese populations.In some individuals,the impaired ability of adipose tissues to recruit new adipocytes to adipose depots during overnutrition results in adipocyte hypertrophy,ectopic lipid accumulation,and insulin resistance.Intervention studies showed that pro-inflammatory cytokine antagonists improve metabolism in patients with metabolic syndrome.This review focuses on the cytokines currently known to regulate adipogenesis under physiological and pathophysiological circumstances.Recent studies on how inhibited adipogenesis leads to metabolic disorders were summarized.Although the interplay of cytokines and lipid metabolism is yet incompletely understood,cytokines represent a class of potential therapeutic targets in the treatment of metabolic disorders.

SARS-CoV-2-encoded nucleocapsid protein acts as a viral suppressor of RNA interference in cells

Dear Editor,Coronaviruses (Co Vs) are large enveloped non-segmented positive-strand RNA viruses that broadly distribute among humans and other animal species, including bats, mice and birds. SARS-Co V-2 infections can cause diseases, named the 2019 novel coronavirus disease (COVID-19). The symptoms of COVID-19 range from mild symptoms to severe respiratory syndromes, including pneumonia, and even death(Chen et al., 2020b;Jiang and Shi, 2020;Xia et al., 2020).

Hepatitis C Virus NS2 Protein Suppresses RNA Interference in Cells

RNAi interference(RNAi)is an evolutionarily conserved post-transcriptional gene silencing mechanism and has been well recognized as an important antiviral immunity in eukaryotes.Numerous viruses have been shown to encode viral suppressors of RNAi(VSRs)to antagonize antiviral RNAi.Hepatitis C virus(HCV)is a medically important human pathogen that causes acute and chronic hepatitis.In this study,we screened all the nonstructural proteins of HCV and found that HCV NS2 could suppress RNAi induced either by small hairpin RNAs(shRNAs)or small interfering RNAs(siRNAs)in mammalian cells.Moreover,we demonstrated that NS2 could suppress RNAi via its direct interaction with doublestranded RNAs(dsRNAs)and siRNAs,and further identified that the cysteine 184 of NS2 is required for the RNAi suppression activity through a serial of point mutation analyses.Together,our findings uncovered that HCV NS2 can act as a VSR in vitro,thereby providing novel insights into the life cycle and virus-host interactions of HCV.

Temporal profiling of plasma cytokines,chemokines and growth factors from mild,severe and fatal COVID-19 patients

Dear Editor,In December 2019,a novel coronavirus that is related to severe acute respiratory syndrome coronavirus(SARS-CoV)and Middle East respiratory syndrome coronavirus(MERS-CoV)in phylogenetic distance was identified.1 This virus,which was later designated as SARS-CoV-2,also causes acute respiratory disease syndrome(ARDS)termed coronavirus disease 2019(COVID-19),which was declared as a pandemic by the World Health Organization in March 2020.

The nonstructural protein 2C of Coxsackie B virus has RNA helicase and chaperoning activities

RNA-remodeling proteins,including RNA helicases and chaperones,play vital roles in the remodeling of structured RNAs.During viral replication,viruses require RNA-remodeling proteins to facilitate proper folding and/or re-folding the viral RNA elements.Coxsackieviruses B3(CVB3)and Coxsackieviruses B5(CVB5),belonging to the genus Enterovirus in the family Picornaviridae,have been reported to cause various infectious diseases such as hand-foot-and-mouth disease,aseptic meningitis,and viral myocarditis.However,little is known about whether CVB3 and CVB5 encode any RNA remodeling proteins.In this study,we showed that 2C proteins of CVB3 and CVB5 contained the conserved SF3 helicase A,B,and C motifs,and functioned not only as RNA helicase that unwound RNA helix bidirectionally in an NTP-dependent manner,but also as RNA chaperone that remodeled structured RNAs and facilitated RNA strand annealing independently of NTP.In addition,we determined that the NTPase activity and RNA helicase activity of 2C proteins of CVB3 and CVB5 were dependent on the presence of divalent metallic ions.Our findings demonstrate that 2C proteins of CVBs possess RNA-remodeling activity and underline the functional importance of 2C protein in the life cycle of CVBs.

Synthesis of Metal Oxides@C(Metal=Ni,Fe) Based Prussian Blue Analogs as a High-performance Anode Material for Lithium-ion Battery

Ni3[Fe(CN)6]2 nano-cubic precursors were prepared by chemical coprecipitation at room temperature with nickel acetate and potas sium ferricyanide as raw materials.The corresponding NiFe2O4-NiO@C composites with excellent crystallization were prepared by two-stage oxidation at low temperature.The microstructure and electrochemical behavior of the materials showed that the Prussian blue analog was transformed into metal oxide while the carbon coating was maintained in the twostage oxidation at low temperature.The existence of the carbon coating reduces the charge transfer impedance to 31.5 Ω.At the current density of 500 mA/g,the reversible capacity of 632.7 mAh/g is maintained after 500 cycles.At the same time,carbon cladding can also enhance the role of pseudocapacitance in the material.At the scanning rate of 0.1 mV/s,the pseudocapacitance account for 54.4% of the total discharge capacity,which is significantly higher than that of uncoated materials.

Longitudinal Characteristics of T Cell Responses in Asymptomatic SARS-CoV-2 Infection

Dear Editor,SARS-Co V-2 causes a spectrum of illness,ranging from an asymptomatic state to life-threatening multi-organ failure,and imposes a high socioeconomic burden on its sufferers and on society(Chen et al.2020;Pan et al.2020).

Feasibility Study of Mixing Throat Swab Samples for Severe Acute Respiratory Syndrome Coronavirus-2 Screening

Dear Editor,The outbreak of coronavirus disease 2019(COVID-19)has been declared a pandemic by the World Health Organization(WHO)and has resulted in the worst public health crisis since World War II(Wang et al.2020).