Magnetic and electronic properties of La-doped hexagonal 4H-SrMnO_(3)

As typical strongly correlated electronic materials, manganites show rich magnetic phase diagrams and electronic structures depending on the doped carrier density. Most previous relevant studies of doped manganites rely on the cubic/orthorhombic structures, while the hexagonal structure is much less studied. Here first-principles calculations are employed to investigate the magnetic and electronic structures of La-doped 4H-SrMnO_(3). By systematically analyzing the two kinds of La-doped positions, our calculations predict that the doped electron with lattice distortion would prefer to form polarons, which contribute to the local magnetic phase transition, nonzero net magnetization, and semiconducting behavior. In addition, the energy gap decreases gradually with increasing doping concentration, indicating a tendency of insulator–metal transition.

Heat shock protein 90 promotes RNA helicase DDX5 accumulation and exacerbates hepatocellular carcinoma by inhibiting autophagy

Objective:Hepatocellular carcinoma(HCC),the main type of liver cancer,has a high morbidity and mortality,and a poor prognosis.RNA helicase DDX5,which acts as a transcriptional co-regulator,is overexpressed in most malignant tumors and promotes cancer cell growth.Heat shock protein 90(HSP90)is an important molecular chaperone in the conformational maturation and stabilization of numerous proteins involved in cell growth or survival.Methods:DDX5 m RNA and protein expression in surgically resected HCC tissues from 24 Asian patients were detected by quantitative real-time PCR and Western blot,respectively.The interaction of DDX5-HSP90 was determined by molecular docking,immunoprecipitation,and laser scanning confocal microscopy.The autophagy signal was detected by Western blot.The cell functions and signaling pathways of DDX5 were determined in 2 HCC cell lines.Two different murine HCC xenograft models were used to determine the function of DDX5 and the therapeutic effect of an HSP90 inhibitor.Results:HSP90 interacted directly with DDX5 and inhibited DDX5 protein degradation in the AMPK/ULK1-regulated autophagy pathway.The subsequent accumulation of DDX5 protein induced the malignant phenotype of HCC by activating theβ-catenin signaling pathway.The silencing of DDX5 or treatment with HSP90 inhibitor both blocked in vivo tumor growth in a murine HCC xenograft model.High levels of HSP90 and DDX5 protein were associated with poor prognoses.Conclusions:HSP90 interacted with DDX5 protein and subsequently protected DDX5 protein from AMPK/ULK1-regulated autophagic degradation.DDX5 and HSP90 are therefore potential therapeutic targets for HCC.

Biomass-Derived Carbon Heterostructures Enable Environmentally Adaptive Wideband Electromagnetic Wave Absorbers

Although advances in wireless technologies such as miniature and wearable electronics have improved the quality of our lives,the ubiquitous use of electronics comes at the expense of increased exposure to electromagnetic(EM)radiation.Up to date,extensive efforts have been made to develop high-performance EM absorbers based on synthetic materials.However,the design of an EM absorber with both exceptional EM dissipation ability and good environmental adaptability remains a substantial challenge.Here,we report the design of a class of carbon heterostructures via hierarchical assembly of graphitized lignocellulose derived from bamboo.Specifically,the assemblies of nanofibers and nanosheets behave as a nanometer-sized antenna,which results in an enhancement of the conductive loss.In addition,we show that the composition of cellulose and lignin in the precursor significantly influences the shape of the assembly and the formation of covalent bonds,which affect the dielectric response-ability and the surface hydrophobicity(the apparent contact angle of water can reach 135°).Finally,we demonstrate that the obtained carbon heterostructure maintains its wideband EM absorption with an effective absorption frequency ranging from 12.5 to 16.7 GHz under conditions that simulate the real-world environment,including exposure to rainwater with slightly acidic/alkaline pH values.Overall,the advances reported in this work provide new design principles for the synthesis of high-performance EM absorbers that can find practical applications in real-world environments.

Weakly supervised temporal action localization with proxy metric modeling

Temporal localization is crucial for action video recognition.Since the manual annotations are expensive and time-consuming in videos,temporal localization with weak video-level labels is challenging but indispensable.In this paper,we propose a weakly-supervised temporal action localization approach in untrimmed videos.To settle this issue,we train the model based on the proxies of each action class.The proxies are used to measure the distances between action segments and different original action features.We use a proxy-based metric to cluster the same actions together and separate actions from backgrounds.Compared with state-of-the-art methods,our method achieved competitive results on the THUMOS14 and ActivityNet1.2 datasets.

Rational construction of graphene oxide with MOF- derived porous NiFe@C nanocubes for high-performance microwave attenuation

Exploring lightweight microwave attenuation materials with strong and tunable wideband microwave absorption is highly desirable but remains a significant challenge. Herein, three-dimensional （3D） porous hybrid composites consisting of NiFe nanoparticles embedded within carbon nanocubes decorated on graphene oxide （GO） sheets （NiFe@C nanocubes@GO） as high-performance microwave attenuation materials have been rationally synthesized. The 3D porous hybrid composites are fabricated by a simple method, which involves one-step pyrolysis of NiFe Prussian blue analogue nanocubes in the presence of GO sheets. Benefiting from the unique structural features that exhibit good magnetic and dielectric losses as well as a proper impedance match, the resulting NiFe@C nanocubes@GO composites show excellent microwave attenuation ability. With a minimum reflection loss （RL） of -51 dB at 7.7 GHz at a thickness of 2.8 mm and maximum percentage bandwidth of 38.6% for RL 〈 -10 dB at a thickness of 2.2 mm, the NiFe@C nanocubes@GO composites are superior to the previously reported state-of-the-art carbon-based microwave attenuation materials.

Emerging role of microRNAs in lipid metabolism

micro RNAs(mi RNAs or mi Rs) are small non-coding RNAs that are involved in posttranscriptional regulation of their target genes in a sequence-specific manner. Emerging evidence demonstrates that mi RNAs are critical regulators of lipid synthesis, fatty acid oxidation and lipoprotein formation and secretion. Dysregulation of mi RNAs disrupts gene regulatory network, leading to metabolic syndrome and its related diseases. In this review, we introduced epigenetic and transcriptional regulation of mi RNAs expression. We emphasized on several representative mi RNAs that are functionally involved into lipid metabolism, including mi R-33/33 n, mi R122, mi R27a/b, mi R378/378 n, mi R-34 a and mi R-21.Understanding the function of mi RNAs in lipid homeostasis may provide potential therapeutic strategies for fatty liver disease.

miR-145 improves metabolic inflammatory disease through multiple pathways

Chronic inflammation plays a pivotal role in insulin resistance and type 2 diabetes,yet the mechanisms are not completely understood.Here,we demonstrated that serum LPS levels were significantly higher in newly diagnosed diabetic patients than in normal control.miR-145 level in peripheral blood mononuclear cells decreased in type 2 diabetics.LPS repressed the transcription of miR-143/145 cluster and decreased miR-145 levels.Attenuation of miR-145 activity by anti-miR-145 triggered liver inflammation and increased serum chemokines in C57BL/6 J mice.Conversely,lentivirus-mediated miR-145 overexpression inhibited macrophage infiltration,reduced body weight,and improved glucose metabolism in db/db mice.And miR-145 overexpression markedly reduced plaque size in the aorta in ApoE−/−mice.Both OPG and KLF5 were targets of miR-145.miR-145 repressed cell proliferation and induced apoptosis partially by targeting OPG and KLF5.miR-145 also suppressed NF-κB activation by targeting OPG and KLF5.Our findings provide an association of the environment with the progress of metabolic disorders.Increasing miR-145 may be a new potential therapeutic strategy in preventing and treating metabolic diseases such as type 2 diabetes and atherosclerosis.

An angle-insensitive electromagnetic absorber enabling a wideband absorption

Electromagnetic(EM)wave absorbers with wideband absorption capability are proposed as a strategy to mitigate environmental pollution by EM waves.However,designing an EM absorber with its performance capacity independent of the EM wave incident angle remains elusive to date.Resolving this challenge requires development of EM absorbers whose EM absorption performance is insensitive to the EM wave incident angle.Herein,we synthesized EM absorbers with a variety of structures with different symme-tries(including micro-/nanospheres,nanoflakes and nanotubes)to study the effect of the EM absorbers’structure and the EM wave incident angle on the EM absorption performance.Our analysis reveals that non-magnetic EM absorbers with spatially symmetric nanostructures exhibit excellent EM wave incident angle-insensitivity.Finally,we demonstrate that a class of non-magnetic EM absorbers made from bam-boo derived-carbon nanospheres exhibit EM incident angle-insensitivity and wideband EM absorption performance with an effective absorption band up to 3.5 GHz when the thickness is 1.4 mm,a signif-icant improvement from prior studies which used thicknesses as high as 3-4 mm for comparable EM absorption performance.

Mitotic motor CENP-E cooperates with PRC1 in temporal control of central spindle assembly

Error-free cell division depends on the accurate assembly of the spindle midzone from dynamic spindle microtubules to ensure chromatid segregation during metaphase-anaphase transition.However,the mechanism underlying the key transition from the mitotic spindle to central spindle before anaphase onset remains elusive.Given the prevalence of chromosome instability phenotype in gastric tumorigenesis,we developed a strategy to model context-dependent cell division using a combination of light sheet microscope and 3D gastric organoids.Light sheet microscopic image analyses of 3D organoids showed that CENP-E inhibited cells undergoing aberrant metaphase-anaphase transition and exhibiting chromosome segregation errors during mitosis.Highresolution real-time imaging analyses of 2D cell culture revealed that CENP-E inhibited cells undergoing central spindle splitting and chromosome instability phenotype.Using biotinylated syntelin as an affinity matrix,we found that CENP-E forms a complex with PRC1 in mitotic cells.Chemical inhibition of CENP-E in metaphase by syntelin prevented accurate central spindle assembly by perturbing temporal assembly of PRC1 to the midzone.Thus,CENP-E-mediated PRC1 assembly to the central spindle constitutes a temporal switch to organize dynamic kinetochore microtubules into stable midzone arrays.These findings reveal a previously uncharacterized role of CENP-E in temporal control of central spindle assembly.Since CENP-E is absent from yeast,we reasoned that metazoans evolved an elaborate central spindle organization machinery to ensure accurate sister chromatid segregation during anaphase and cytokinesis.

Modeling of COVID-19 disease disparity in gastric organoids reveals the spatiotemporal dynamics of SARS-CoV-2 infectivity

Dear Editor,The promptness and continuous expansion of the coronavirus disease 2019(COVID-19)pandemic,elicited by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and its variants,has presented an unprecedented impact on human health(WHO Coronavirus(COVID-19)Dashboard,2021).Although vaccination has attenuated the severe symptoms,there is no specific antiviral medication available for preventing the viral spread(Drayman et al.,2021).

Energy Procurement and Retail Pricing for Electricity Retailers via Deep Reinforcement Learning with Long Short-term Memory

The joint optimization problem of energy procurement and retail pricing for an electricity retailer is converted into separately determining the optimal procurement strategy and optimal pricing strategy,under the“price-taker”assumption.The aggregate energy consumption of end use customers(EUCs)is predicted to solve for the optimal procurement strategy vis a long short-term memory(LSTM)-based supervised learning method.The optimal retail pricing problem is formulated as a Markov decision process(MDP),which can be solved by using deep reinforcement learning(DRL)algorithms.However,the performance of existing DRL approaches may deteriorate due to their insufficient ability to extract discriminative features from the time-series vectors in the environmental states.We propose a novel deep deterministic policy gradient(DDPG)network structure with a shared LSTM-based representation network that fully exploits the Actor’s and Critic’s losses.The designed shared representation network and the joint loss function can enhance the environment perception capability of the proposed approach and further improve the optimization performance,resulting in a more profitable pricing strategy.Numerical simulations demonstrate the effectiveness of the proposed approach.

Article Navigation Syntelin inhibits triple-negative breast cancer cell proliferation and metastasis

Dear Editor,The hallmarks of cancer comprise several distinct biological characteristics acquired during the multistep development of human tumors with the unique feature of genomic instability(Shen,2011).These cancer characteristics include sustaining proliferative signaling,evading growth suppressors,resisting cell death,enabling replicative immortality,inducing angiogenesis,and activating invasion and metastasis(Chen et al.,2011;Song et al.,2018).Triple-negative breast cancer(TNBC),an aggressive disease with increased risks for visceral metastases,has a poor prognosis due to unavailable and viable therapeutic targets(Bianchini et al.,2016).A TNBC diagnosis indicates that cancer cells test negative for three key receptors:estrogen receptor,progesterone receptor,and human epidermal growth factor receptor 2(Bianchini et al.,2016).The absence of these three receptors renders existing hormone and targeted therapies ineffective.

Effects of baffles on separation of aqueous ethanol solution with hollow fibers

The effects of baffles on the operation and mass-transfer characteristics in novel hollowfiber membrane contactor used in distillation were investi-gated.Hollowfiber membranes,coated with a 7μm polydimethyl-siloxane,were operated as structural packing in the separation of ethanol-water solutions.The parallelflow mode was chosen for separation due to the stronger driving force of the concentration difference,in which liquidflows through the lumens of thefibers and vaporflows countercurrent-wise outside thefibers.Two baffles were installed on the shell side of the membrane contactors to enhance separation,which had a round shape with a semi-lunar hole.The results show that both baffled and unbaffled membrane contactors gave better,more produc-tive separations than traditional packing in distillation,such as the excellent Sulzer Gauze BX structured packing.The baffled membrane contactors performed better than unbaffled ones,especially at high vapor velocities.The minimal HTU of membrane contactor with baffles could reach as low as 4.5 cm,and almost all the contactors could work well above the limit whereflooding normally occurs in conventional cases.Theoretical analysis predicted that baffles helped membrane module to obtain a higher mass-transfer coefficient and a smaller mass-transfer resistance.Finally,theoretical mass-transfer coefficient and experi-mental value were compared as well as the contribution of each individual mass-transfer coefficients among liquid,gas and membrane.

Hierarchical porous hollow graphitized carbon@MoS_(2)with wideband EM dissipation capability

Core-shell materials are promising broadband electromagnetic(EM)absorption materials since the highly component manipulation performance,interfacial effect etc.Herein,a well-defined core-shell shaped structure constructed by 2-dimensional Mo S_(2)nanosheets-coated porous hollow carbon has been successfully designed with controlled pore-sizes of the core,adjustable shell content,and structure.By effectively optimizing the parameters for these factors,the as-prepared hierarchical porous hollow C@Mo S_(2)sample enables an ultra-width EM absorption ability(covering 11.4-18.0 GHz)at a thickness of only 2.0 mm.The detailed contributions of each component and structure on the excellent EM absorption capability have been investigated.These encouraging results indicate that the development of core-shell composites with multiple controllable physical factors is of great significance for the future ultra-wideband electromagnetic absorbers.

Optimization of Ni_(0.95-x)Zn_(x)Co_(0.05)Fe_(1.90)Mn_(0.02)O_(4) ceramics with promising magneto-dielectric properties for VHF antenna miniaturization

Magnetic,dielectric and DC conductive properties of Ni_(0.95-x)Zn_(x)Co_(0.05)Fe_(1.90)Mn_(0.02)O_(4)(with x=0-0.20 at an interval of 0.05)ferrite ceramics were studied,in order to develop magneto-dielectric materials with almost equal values of relative permeability and permittivity,for the miniaturization of HF(3-30 MHz)and VHF(30-90MHz and 100-300 MHz)antennas.The ferrite ceramics were prepared by using the conventional two-step sintering process.The real part of relative permeability is increased almost linearly with increasing concentration of Zn,while that of relative permittivity keeps nearly unchanged.It is found that promising magneto-dielectric materials,with close values of real permeability and permittivity over 30-90 MHz(VHF),can be obtained for the samples at Zn concentrations between x=0.05 and x=0.10.

Rapid processing of ferrite ceramics with promising magneto-dielectric characteristics

Ferrite ceramics,Ni_(0.88)Zn_(0.07)Co_(0.05)Fe_(1.98)O_(4),with the addition of 4 wt.%Bi_(2)O_(3) as sintering aid,were fabricated by using a simple one-step processing without involving the step of calcination.X-ray diffraction(XRD)results indicated that single phase ferrite ceramics can be achieved after sintering at 1000℃ for 2 h.The samples demonstrated relative densities in the range of 97-99%.Desired magneto-dielectric properties have been approached by adjusting the sintering temperature and sintering time duration.This technique is believed to be applicable to other ceramic materials.