Synergistic effects of planting density and nitrogen fertilization on chlorophyll degradation and leaf senescence after silking in maize

Regulating planting density and nitrogen(N)fertilization could delay chlorophyll(Chl)degradation and leaf senescence in maize cultivars.This study measured changes in ear leaf green area(GLA_(ear)),Chl content,the activities of Chl a-degrading enzymes after silking,and the post-silking dry matter accumulation and grain yield under multiple planting densities and N fertilization rates.The dynamic change of GLA_(ear)after silking fitted to the logistic model,and the GLA_(ear) duration and the GLAearat 42 d after silking were affected mainly by the duration of the initial senescence period(T_(1))which was a key factor of the leaf senescence.The average chlorophyllase(CLH)activity was 8.3 times higher than pheophytinase activity and contributed most to the Chl content,indicating that CLH is a key enzyme for degrading Chl a in maize.Increasing density increased the CLH activity and decreased the Chl content,T1,GLAear,and GLA_(ear) duration.Under high density,appropriate N application reduced CLH activity,increased Chl content,prolonged T1,alleviated high-density-induced leaf senescence,and increased post-silking dry matter accumulation and grain yield.

Avibacterium paragallinarum: an emerging birds pathogen in Qinling wildlife conservation center, China

The bacterium Avibacterium paragallinarum,previously known as Haemophilus paragallinarum,is responsible for caus-ing infectious coryza(IC)in chickens and other avian species.In this case report,an outbreak of Avibacterium paragal-linarum occurred in the Qinling area of China,resulting in clinical symptoms of facial swelling in several bird species,including Golden pheasant,Temminck's tragopan,and Peafowls,and three Golden pheasants died due to prolonged infection.Specific PCR results confrmed the presence of the pathogen in the infected birds.The report describes the clinical symptoms and pathological changes observed in the affected birds,as well as the isolation and identification of Avibacterium paragallinarum.Whole-genome sequencing and phylogenetic anal sis y were performed,and this is the frst report of inter-and intra-species transmission of infectious coryza among wild birds in China.

Innovative Design and Additive Manufacturing of Regenerative Cooling Thermal Protection System Based on the Triply Periodic Minimal Surface Porous Structure

The new regenerative cooling thermal protection system exhibits the multifunctional characteristics of load-carrying and heat exchange cooling,which are fundamental for the lightweight design and thermal protection of hypersonic vehicles.Triply periodic minimal surface(TPMS)is especially suitable for the structural design of the internal cavity of regenerative cooling structures owing to its excellent structural characteristics.In this study,test pieces were manufactured using Ti6Al4V lightweight material.We designed three types of porous test pieces,and the interior was filled with a TPMS lattice(Gyroid,Primitive,I-WP)with a porosity of 30%.All porous test pieces were manufactured via selective laser melting technology.A combination of experiments and finite element simulations were performed to study the selection of the internal cavity structure of the regenerative cooling thermal protection system.Hence,the relationship between the geometry and mechanical properties of a unit cell is established,and the deformation mechanism of the porous unit cell is clarified.Among the three types of porous test pieces,the weight of the test piece filled with the Gyroid unit cell was reduced by 8.21%,the average tensile strength was reduced by 17.7%compared to the solid test piece,while the average tensile strength of the Primitive and I-WP porous test pieces were decreased by 30.5%and 33.3%,respectively.Compared with the other two types of unit cells,Gyroid exhibited better mechanical conductivity characteristics.Its deformation process was characterised by stretching,shearing,and twisting,while the Primitive and I-WP unit cells underwent tensile deformation and tensile and shear deformation,respectively.The finite element predictions in the study agree well with the experimental results.The results can provide a basis for the design of regenerative cooling thermal protection system.

AI-assisted food enzymes design and engineering:a critical review

Food enzymes are basic components used for food processing.Through catalysis,food enzymes can function as removing allergy,enriching absorbable nutrients,improving food texture,and adjusting flavors.Food enzymes work in various conditions,which brought out the need for engineering these enzymes with harsh environment tolerance and higher catalytic efficiency.Artificial intelligence(AI)has recently provided solutions for structural modeling,finding modification hot spots,and guiding mutations toward specific needs,which greatly benefit enzyme engineering.AI-based tools showed great advantages in cutting down the computational time,enabling higher prediction accuracy,and providing trainable models suited for wide uses.In this review,we describe the functions and uses of food enzymes,as well as their utility limitations.The necessity and advantages of using AI-based tools in enzyme engineering,and the differences between using traditional and AI-based tools are mainly discussed.Few AI-based tools for enzyme engineering were introduced and described their function.The perspective of using AI tools and the future challenges were discussed.

A local spectrum enhancement-based method and its application in incipient fault diagnosis of rotating machinery

Incipient faults of gears and rolling bearings in rotating machineries are very difficult to identify using traditional envelope analysis methods.To address this challenge,this paper proposes an effective local spectrum enhancement‐based diagnostic method that can identify weak fault frequencies in the original complicated raw signals.For this purpose,a traversal frequency band segmentation technique is first proposed for dividing the raw signal into a series of subfrequency bands.Then,the proposed synthetic quantitative index is constructed for selecting the most informative local frequency band(ILFB)containing fault features from the divided subfrequency bands.Furthermore,an improved grasshopper optimization algorithmbased stochastic resonance(SR)system is developed for enhancing weak fault features contained in the selected most ILFB with less computation cost.Finally,the enhanced weak fault frequencies are extracted from the output of the SR system using a common spectrum analysis.Two experiments on a laboratory planetary gearbox and an open bearing data set are used to verify the effectuality of the proposed method.The diagnostic results demonstrate that the proposed method can identify incipient faults of gears and bearings in an effective and accurate manner.Furthermore,the advantages of the proposed method are highlighted by comparison with other methods.

Neuronal failure in Alzheimer's disease: a view through the oxidative stress looking-glass

Considerable debate and controversy surround the cause（s） of AIzheimer＇s disease （AD）. To date, several theories have gained notoriety, however none is universally accepted. In this review, we provide evidence for the oxidative stress-induced AD cascade that posits aged mitochondria as the critical origin of neurodegeneration in AD.

Exosomes derived from differentiated human ADMSC with the Schwann cell phenotype modulate peripheral nerve-related cellular functions

Peripheral nerve regeneration remains a significant clinical challenge due to the unsatisfactory functional recovery and public health burden.Exosomes,especially those derived from mesenchymal stem cells(MSCs),are promising as potential cell-free therapeutics and gene therapy vehicles for promoting neural regeneration.In this study,we reported the differentiation of human adipose derived MSCs(hADMSCs)towards the Schwann cell(SC)phenotype(hADMSC-SCs)and then isolated exosomes from hADMSCs with and without differentiation(i.e.,dExo vs uExo).We assessed and compared the effects of uExo and dExo on antioxidative,angiogenic,anti-inflammatory,and axon growth promoting properties by using various peripheral nerve-related cells.Our results demonstrated that hADMSC-SCs secreted more neurotrophic factors and other growth factors,compared to hADMSCs without differentiation.The dExo isolated from hADMSC-SCs protected rat SCs from oxidative stress and enhanced HUVEC migration and angiogenesis.Compared to uExo,dExo also had improved performances in downregulating pro-inflammatory gene expressions and cytokine secretions and promoting axonal growth of sensory neurons differentiated from human induced pluripotent stem cells.Furthermore,microRNA(miRNA)sequencing analysis revealed that exosomes and their parent cells shared some similarities in their miRNA profiles and exosomes displayed a distinct miRNA signature.Many more miRNAs were identified in dExo than in uExo.Several upregulated miRNAs,like miRNA-132-3p and miRNA-199b-5p,were highly related to neuroprotection,anti-inflammation,and angiogenesis.The dExo can effectively modulate various peripheral nerve-related cellular functions and is promising for cell-free biological therapeutics to enhance neural regeneration.

Mitochondrial dynamic abnormalities in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis(ALS)is the most common motor neuron disease characterized by progressive loss of motor neurons in the brainstem and spinal cord.Currently,there is no cure or effective treatment for ALS and the cause of disease is unknown in the majority of ALS cases.Neuronal mitochondria dysfunction is one of the earliest features of ALS.Mitochondria are highly dynamic organelles that undergo continuous fission,fusion,trafficking and turnover,all of which contribute to the maintenance of mitochondrial function.Abnormal mitochondrial dynamics have been repeatedly reported in ALS and increasing evidence suggests altered mitochondrial dynamics as possible pathomechanisms underlying mitochondrial dysfunction in ALS.Here,we provide an overview of mitochondrial dysfunction and dynamic abnormalities observed in ALS,and discuss the possibility of targeting mitochondrial dynamics as a novel therapeutic approach for ALS.

Posttranslational modifications of α-tubulin in alzheimer disease

Background:In Alzheimer disease(AD),hyperphosphorylation of tau proteins results in microtubule destabilization and cytoskeletal abnormalities.Our prior ultra-morphometric studies documented a clear reduction in microtubules in pyramidal neurons in AD compared to controls,however,this reduction did not coincide with the presence of paired helical filaments.The latter suggests the presence of compensatory mechanism(s)that stabilize microtubule dynamics despite the loss of tau binding and stabilization.Microtubules are composed of tubulin dimers which are subject to posttranslational modifications that affect the stability and function of microtubules.Methods:In this study,we performed a detailed analysis on changes in the posttranslational modifications in tubulin in postmortem human brain tissues from AD patients and age-matched controls by immunoblot and immunocytochemistry.Results:Consistent with our previous study,we found decreased levels ofα-tubulin in AD brain.Levels of tubulin with various posttranslational modifications such as polyglutamylation,tyrosination,and detyrosination were also proportionally reduced in AD brain,but,interestingly,there was an increase in the proportion of the acetylatedα-tubulin in the remainingα-tubulin.Tubulin distribution was changed from predominantly in the processes to be more accumulated in the cell body.The number of processes containing polyglutamylated tubulin was well preserved in AD neurons.While there was a cell autonomous detrimental effect of NFTs on tubulin,this is likely a gradual and slow process,and there was no selective loss of acetylated or polyglutamylated tubulin in NFT-bearing neurons.Conclusions:Overall,we suggest that the specific changes in tubulin modification in AD brain likely represent a compensatory response.