Numerical simulation of melt flow and temperature field during DC casting 2024 aluminium alloy under different casting conditions

Casting speed,casting temperature and secondary cooling water flow rate are the main process parameters affecting the DC casting process.These parameters significantly influence the flow and temperature fields during casting,which are crucial for the quality of the ingot and can determine the success or failure of the casting operation.Numerical simulation,with the advantages of low cost,rapid execution,and visualized results,is an important method to study and optimize the DC casting process.In the present work,a simulation model of DC casting 2024 aluminum alloy was established,and the reliability of the model was verified.Then,the influence of casting parameters on flow field and temperature field was studied in detail by numerical simulation method.Results show that with the increase of casting speed,the melt flow becomes faster,the depths of slurry zone and mushy zone increase,and the variation of slurry zone depth is greater than that of mushy zone.With an increase in casting temperature,the melt flow rate increases,the depth of the slurry zone becomes shallower,and the depth of the mushy zone experiences only minor changes.The simulation results further indicate that the increase of the flow rate of the secondary cooling water slightly reduces the depths of both slurry and mushy zone.

Central Asia revealed as a key area in evolution of Eremurus (Asphodelaceae)

Eremurus was described at the beginning of the 19th century.However,due to limited sampling and the small number of gene markers to date,its phylogeny and evolution are largely unknown.In this study,we analyzed plastomes from 27 species belonging to 2 subgenera and 3 sections of Eremurus,which are found in Central Asia(its center of diversity)and China.We also analyzed nuclear DNA ITS of 33 species,encompassing all subgenera and sections of the genus in Central Asia,southwest Asia and China.Our findings revealed that the genus was monophyletic,although both subgenera Eremurus and Henningia were found to be paraphyletic.Both plastome and nrDNA-based phylogenetic trees had three clades that did not reflect the current taxonomy of the genus.Our biogeographical and time-calibrated trees suggest that Eremurus originated in the ancient Tethyan area in the second half of the Eocene.Diversification of Eremurus occurred from the early Oligocene to the late Miocene.Paratethys Sea retreat and several orogenetic events,such as the progressive uplift of the Qinghai-Tibet Plateau and surrounding mountain belts(Altai,Pamir,Tian Shan),caused serious topographic and climate(aridification)changes in Central Asia that may have triggered a split of clades and speciation.In this transformed Central Asia,speciation proceeded rapidly driven mainly by vicariance caused by numerous mountain chains and specialization to a variety of climatic,topographic and soil conditions that exist in this region.

Activity Pattern and Habitat Use of Shorebirds in an Artificial Wetland Complex:A Case Study of Breeding Pied Avocet in the Yellow River Delta,China

With the loss of substantial natural wetlands in coastal zones,artificial wetlands provide alternative habitats for many shorebirds.Scientific management of artificial wetlands used by shorebirds plays an important role in maintaining the stability of shorebird population.Satellite tracking technique can obtain high-precision location information of individuals day and night,providing a good technical support for the study of quantitative relationship between waterfowls and their habitats.In this study,satellite tracking method,Remote Sensing(RS)and Geographic Information System(GIS)technology were used to analyze the activity pattern and habitat utilization characteristics of Pied Avocet during breeding period in an artificial wetland complex in the Yellow River Delta(YRD),China.The results showed that the breeding Pied Avocets had a small range of activity,with a total core and main home range of 33.10 km^(2) and 216.30 km^(2),respectively.This species tended to forage in the pond and salt pan during the day and night,respectively,with an unfixed staying time in the breeding ground.The distance between breeding ground and feeding ground was less than 6 km.It is emphasized that in addition to improving the conditions of the remaining natural habitats,effective managing artificial habitats is a priority for shorebird conservation.This research could provide reference for the management of artificial wetlands in coastal zones and supply technique support for the protection of shorebirds and their habitats,and alleviate human-bird conflicts and sustainable development of coastal zones.

Tomographic inversion of OBS converted shear waves:case study of profile EW6 in the Dongsha area

Studies of converted S-wave data recorded on the ocean bottom seismometer(OBS)allow for the estimation of crustal S-wave velocity,from which is further derived the Vp/Vs ratio to constrain the crustal lithology and geophysical properties.Constructing a precise S-wave velocity model is important for deep structural research,and inversion of converted S-waves provides a potential solution.However,the inversion of the converted S-wave remains a weakness because of the complexity of the seismic ray path and the inconsistent conversion interface.In this study,we introduced two travel time correction methods for the S-wave velocity inversion and imaged different S-wave velocity structures in accordance with the corresponding corrected S-wave phases using seismic data of profile EW6 in the northeastern South China Sea(SCS).The two inversion models show a similar trend in velocities,and the velocity difference is<0.15 km/s(mostly in the range of 0–0.1 km/s),indicating the accuracy of the two travel time correction methods and the reliability of the inversion results.According to simulations of seismic ray tracing based on different models,the velocity of sediments is the primary influencing factor in ray tracing for S-wave phases.If the sedimentary layer has high velocities,the near offset crustal S-wave refractions cannot be traced.In contrast,the ray tracing of Moho S-wave reflections was not significantly impacted by the velocity of the sediments.The two travel time correction methods have their own advantages,and the application of different approaches is based on additional requirements.These works provide an important reference for future improvements in converted S-wave research.

Development of a single transcript CRISPR/Cas9 toolkit for efficient genome editing in autotetraploid alfalfa

Alfalfa(Medicago sativa.L.)is a globally significant autotetraploid legume forage crop.However,despite its importance,establishing efficient gene editing systems for cultivated alfalfa remains a formidable challenge.In this study,we pioneered the development of a highly effective ultrasonic-assisted leaf disc transformation system for Gongnong 1 alfalfa,a variety widely cultivated in Northeast China.Subsequently,we created a single transcript CRISPR/Cas9(CRISPR_2.0)toolkit,incorporating multiplex gRNAs,designed for gene editing in Gongnong 1.Both Cas9 and gRNA scaffolds were under the control of the Arabidopsis ubiquitin-10 promoter,a widely employed polymeraseⅡconstitutive promoter known for strong transgene expression in dicots.To assess the toolkit’s efficiency,we targeted PALM1,a gene associated with a recognizable multifoliate phenotype.Utilizing the CRISPR_2.0 toolkit,we directed PALM1 editing at two sites in the wild-type Gongnong 1.Results indicated a 35.1%occurrence of editing events all in target 2 alleles,while no mutations were detected at target 1 in the transgenic-positive lines.To explore more efficient sgRNAs,we developed a rapid,reliable screening system based on Agrobacterium rhizogenes-mediated hairy root transformation,incorporating the visible reporter MtLAP1.This screening system demonstrated that most purple visible hairy roots underwent gene editing.Notably,sgRNA3,with an 83.0%editing efficiency,was selected using the visible hairy root system.As anticipated,tetra-allelic homozygous palm1 mutations exhibited a clear multifoliate phenotype.These palm1 lines demonstrated an average crude protein yield increase of 21.5%compared to trifoliolate alfalfa.Our findings highlight the modified CRISPR_2.0 system as a highly efficient and robust gene editing tool for autotetraploid alfalfa.

A New Species of the Genus Scincella Mittleman, 1950 (Squamata: Scincidae)from Sichuan Province, Southwest China, with a Diagnostic Key of Scincella Species in China

The genus Scincella Mittleman,1950 of the family Scincidae currently includes 38 species."To date,however,taxonomic assessment remains challenging.Here,phylogenetic analyses based on DNA sequences of four mitochondrial genes supported a putative new species from Sichuan Province,Southwest China,as an independent lineage.Uncorrected genetic distance of 16S rRNA between the new species and closest congener was 8%,and the population was morphologically distinguishable from all other known congeners.We herein describe the Scincella population as anew species based on both phylogeny and comparative morphology.The new species can be distinguished from its congeners by a combination of the following morphological characters:(1)body slender,mediumsized,snout-vent length 35.0-62.1 mm;(2)infralabials seven,rarely eight;(3)supraciliaries 5-7;(4)tympanum deeply sunk without lobules;(5)midbody scale-row counts 27-30;(6)dorsal scales smooth and enlarged,paravertebral scale-row counts 60-75,ventral scalerow counts 46-59,gulars 25-30;(7)upper edge of lateral longitudinal stripes relatively straight with six rows of dorsal scales in middle;(8)number of enlarged,undivided lamellae beneath fingerⅣ9-11,number of enlarged,undivided lamellae beneath toeⅣ13-16;(9)ventral side of tail densely ornamented with dark brown or black spots;and(10)grayish-brown discontinuous regular dorsal stripes 5-7,distinct black dorsolateral stripes,starting from posterior corner of eye and continuing to lateral side of tail.A diagnostic key to all Scincella members from China is also provided The new species is currently only known from Wenchuan and Lixian counties,Sichuan Province,China,and brings the number of Scincella species in China to 12.This study emphasizes the incompleteness of knowledge on herpetodiversity in China.

Unique characteristics of gut microbiota in black snub-nosed monkeys(Rhinopithecus strykeri) reveal an enzymatic mechanism of adaptation to dietary vegetation

DEAR EDITOR,The Myanmar or black snub-nosed monkey(Rhinopithecus strykeri) is a recently discovered and critically endangered colobus primate with an unknown gut microbiota. Here, we characterized and compared the gut microbiota of R. strykeri with those of two closely related snub-nosed monkey species.

Microscopic study on the key process and influence of efficient synthesis of natural gas hydrate by in situ Raman analysis of water microstructure in different systems with temperature drop

Gas hydrate technology has considerable potential in many fields.However,due to the lack of understanding of the micro mechanism of hydrate formation,it has not been commercially applied so far.Gas hydrate formation is essentially a gas-liquid-solid phase transition of water and gas molecules at a certain temperature and pressure.The key to the hydrate formation is the transformation of water molecule from disordered arrangement to ordered arrangement.In this process,weakly hydrogen bonded water will be correspondingly converted to strongly hydrogen bonded water.Through in situ Raman analysis and experiments,the position change of the corresponding peaks of the strongly hydrogen bonded water and the weakly hydrogen bonded water was compared in this work,and the key microscopic process and influence of gas hydrate formation in different systems were comprehensively studied and summarized.It is found that,with the decrease of temperature,the OAH of the weakly hydrogen bonded water remains unchanged when the temperature drops to a certain value,which is the key to the transformation of water into cage hydrate rather than ice.The conversion from the weakly hydrogen bonded water to the strongly hydrogen bonded water is closely related to the gas-liquid interface force,the hydrophilicity/hydrophobicity of the promoter,the ionization degree of liquid,and the electrostatic field of the system.Among the four most common promoters,tetrahydrofuran(THF)has the highest efficiency in promoting methane(CH4)hydrate formation.Therefore,this study provides a scientific direction and basis for the development of high efficient hydrate formation promoters,which can effectively weaken the hydrogen bond of weakly hydrogen bonded water and promote the conversion of weakly hydrogen bonded water to strongly hydrogen bonded water.

Probing the processing of facial expressions in monkeys via time perception and eye tracking

Accurately recognizing facial expressions is essential for effective social interactions.Non-human primates(NHPs)are widely used in the study of the neural mechanisms underpinning facial expression processing,yet it remains unclear how well monkeys can recognize the facial expressions of other species such as humans.In this study,we systematically investigated how monkeys process the facial expressions of conspecifics and humans using eye-tracking technology and sophisticated behavioral tasks,namely the temporal discrimination task(TDT)and face scan task(FST).We found that monkeys showed prolonged subjective time perception in response to Negative facial expressions in monkeys while showing longer reaction time to Negative facial expressions in humans.Monkey faces also reliably induced divergent pupil contraction in response to different expressions,while human faces and scrambled monkey faces did not.Furthermore,viewing patterns in the FST indicated that monkeys only showed bias toward emotional expressions upon observing monkey faces.Finally,masking the eye region marginally decreased the viewing duration for monkey faces but not for human faces.By probing facial expression processing in monkeys,our study demonstrates that monkeys are more sensitive to the facial expressions of conspecifics than those of humans,thus shedding new light on inter-species communication through facial expressions between NHPs and humans.

Acute effect of twice-daily 15 mA transcranial alternating current stimulation on treatment-resistant depression: a case series study

Totheeditor:Major depressive disorder(MDD)is a principal cause of disability worldwide and is often associated with high morbidity and mortality rates.Although there are several therapies available for the treatment of depression,about one-third of patients with MMD will not respond to two or more antidepressant drugs with different mechanisms;the patients are then referred to as having treatment-resistant depression(TRD).Patients with TRD have a poorer quality of life,greater economic burden and increased suicidal behaviours.Therefore,new antidepressant treatments that are effective,safe,long-lasting and tolerable are needed.Ketamine infusion,intranasal esketamine and transcranial magnetic stimulation(TMS)have been used to treat early stage TRD.’A recent review suggests that electroconvulsive therapy(ECT)may be superior to ketamine for reducing depression severity in the acute treatment of TRD.

New correlations for evaluating the equivalent bare charge mass for a cased charge

Munitions contain casings that consume explosive energy.The blast load(e.g.,peak overpressure and maximum impulse)intensity generated by ammunition explosion will be lower than that generated by a bare charge with equal mass.To evaluate the blast load of a cased charge under different conditions,the equivalent bare mass needs to be calculated.However,the accuracy of existing correlations strongly depends on the empirical determination of relevant controlling parameters and lacks theoretical clarification.In this paper,new correlations are proposed based on a more rigorous theoretical derivation,considering both the mechanical behaviors of the casing’s material and the change of the polytropic exponent during the expansion process of the explosion products.The controlling parameters are attributed to the rupture radius ratio and the polytropic exponent of detonation products expansion to casing rupture state.The reasonability is validated by both comprehensive numerical simulations with dynamic mechanical constitutive model and theoretical derivations.The results calculated by the new correlation show better agreement with the experimental results than those calculated by previous correlations,and the results difference is explained in more consistency with the thermos-physical properties of the charge and mechanical behaviors of casing material.Furthermore,the correlation of the cased-to-bare impulse ratio is also theoretically improved,providing a more accurate theoretical basis for both the equivalent bare mass and impulse evaluation for a cased charge.

Generation of chimeric monkeys using embryonic stem cells

Embryonic stem cells(ESCs)represent a subtype of pluripotent stem cells(PSCs)derived from the inner cell mass of blastocysts.These cells exhibit three principal features:the capacity for unlimited self-replication,the ability to differentiate into diverse somatic cell types in vitro,and the potential to contribute to chimera animals in vivo upon reintroduction into the host blastocyst.Thus,ESCs are widely used in basic and biomedical research,as well as in applications such as cell replacement therapy and the creation of genetically modified animal models.

The high-quality Pinellia pedatisecta genome reveals a key role of tandem duplication in the expansion of its agglutinin genes

Dear Editor,Pinellia Tenore,a small genus of the monocot family Araceae,consists of only nine perennial herbaceous species and is mainly distributed in East Asia[1].Pinellia plants have been widely used as herbal medicines in Asia for over 2000 years.Among these species,P.ternata and P.pedatisecta are most widely used as traditional medicinal herbs[2].In China,the medicinal utilization of P.ternata and P.pedatisecta was first documented in the Divine Farmer’s Materia Medica(Chinese name:‘Shennong Bencao Jing’)during the Eastern Han dynasty(25–250 AD).Tubers produced by these plants have been traditionally utilized to treat vomiting,infection,and inf lammation[3].Modern pharmacological studies have indicated that the pharmacological effects of Pinellia plants are closely related to endogenous components,such as plant lectins,alkaloids,amino acids,nucleosides,and polysaccharides[2].P.ternata has been listed in the Chinese Pharmacopoeia as a common traditional Chinese medicine.However,to date no genomic resources have been reported in the genus Pinellia,which greatly limits further studies on this valuable resource.

Influence of Arctic Sea-ice Concentration on Extended-range Forecasting of Cold Events in East Asia

Utilizing the Community Atmosphere Model,version 4,the influence of Arctic sea-ice concentration(SIC)on the extended-range prediction of three simulated cold events(CEs)in East Asia is investigated.Numerical results show that the Arctic SIC is crucial for the extended-range prediction of CEs in East Asia.The conditional nonlinear optimal perturbation approach is adopted to identify the optimal Arctic SIC perturbations with the largest influence on CE prediction on the extended-range time scale.It shows that the optimal SIC perturbations are more inclined to weaken the CEs and cause large prediction errors in the fourth pentad,as compared with random SIC perturbations under the same constraint.Further diagnosis reveals that the optimal SIC perturbations first modulate the local temperature through the diabatic process,and then influence the remote temperature by horizontal advection and vertical convection terms.Consequently,the optimal SIC perturbations trigger a warming center in East Asia through the propagation of Rossby wave trains,leading to the largest prediction uncertainty of the CEs in the fourth pentad.These results may provide scientific support for targeted observation of Arctic SIC to improve the extended-range CE prediction skill.

2D seismic interpretation of Sawan gas field integrated with petrophysical analysis:A case study from Lower Indus Basin,Pakistan

The Lower Indus Basin is the leading hydrocarbon-bearing sedimentary basin in Pakistan.This study has been conducted on the Sawan gas field located in the Lower Indus Basin,adjacent to a few other wellknown gas fields of Pakistan like Kadanwari,Qadirpur,and Miano gas fields.This research aims to present the spatial distribution and reservoir potential of the productive zones of the Lower Goru Formation.The present study utilized various two-dimensional(2D)seismic lines and well-log data(Sawan-01 and Sawan-02)to investigate the structural and stratigraphic features of the area.The stratigraphic layers are mildly deepening in the southeast direction.The 2D seismic interpretation of the research area identifies the existence of extensional remanents,i.e.,normal faults.These extensional structures are associated with horst and graben geometry that acts as a trapping mechanism for hydrocarbons.Wireline logs are used to identify the reservoir's diverse lithology and petrophysical properties.Petrophysical results indicate fair to good effective porosities,low shale volume,and high hydrocarbon saturation(>55%),signifying good reservoir potential in C interval of the Lower Goru Formation.

Triboelectric‘electrostatic tweezers'for manipulating droplets on lubricated slippery surfaces prepared by femtosecond laser processing

The use of‘Electrostatic tweezers'is a promising tool for droplet manipulation,but it faces many limitations in manipulating droplets on superhydrophobic surfaces.Here,we achieve noncontact and multifunctional droplet manipulation on Nepenthes-inspired lubricated slippery surfaces via triboelectric electrostatic tweezers(TETs).The TET manipulation of droplets on a slippery surface has many advantages over electrostatic droplet manipulation on a superhydrophobic surface.The electrostatic field induces the redistribution of the charges inside the neutral droplet,which causes the triboelectric charged rod to drive the droplet to move forward under the electrostatic force.Positively or negatively charged droplets can also be driven by TET based on electrostatic attraction and repulsion.TET enables us to manipulate droplets under diverse conditions,including anti-gravity climb,suspended droplets,corrosive liquids,low-surface-tension liquids(e.g.ethanol with a surface tension of 22.3 mN·m^(-1)),different droplet volumes(from 100 nl to 0.5 ml),passing through narrow slits,sliding over damaged areas,on various solid substrates,and even droplets in an enclosed system.Various droplet-related applications,such as motion guidance,motion switching,droplet-based microreactions,surface cleaning,surface defogging,liquid sorting,and cell labeling,can be easily achieved with TETs.

Mitophagy in neurodegenerative disease pathogenesis

Mitochondria are critical cellular energy resources and are central to the life of the neuron.Mitophagy selectively clears damaged or dysfunctional mitochondria through autophagic machinery to maintain mitochondrial quality control and homeostasis.Mature neurons are postmitotic and consume substantial energy,thus require highly efficient mitophagy pathways to turn over damaged or dysfunctional mitochondria.Recent evidence indicates that mitophagy is pivotal to the pathogenesis of neurological diseases.However,more work is needed to study mitophagy pathway components as potential therapeutic targets.In this review,we briefly discuss the characteristics of nonselective autophagy and selective autophagy,including ERphagy,aggrephagy,and mitophagy.We then introduce the mechanisms of Parkin-dependent and Parkin-independent mitophagy pathways under physiological conditions.Next,we summarize the diverse repertoire of mitochondrial membrane receptors and phospholipids that mediate mitophagy.Importantly,we review the critical role of mitophagy in the pathogenesis of neurodegenerative diseases including Alzheimer’s disease,Parkinson’s disease,and amyotrophic lateral sclerosis.Last,we discuss recent studies considering mitophagy as a potential therapeutic target for treating neurodegenerative diseases.Together,our review may provide novel views to better understand the roles of mitophagy in neurodegenerative disease pathogenesis.

Electrochemical Hydrogen Charging on Corrosion Behavior of Ti-6Al-4V Alloy in Artificial Seawater

This study employs advanced electrochemical and surface characterization techniques to investigate the impact of electrochemical hydrogen charging on the corrosion behavior and surface film of the Ti-6Al-4V alloy.The findings revealed the formation ofγ-TiH andδ-TiH_(2) hydrides in the alloy after hydrogen charging.Prolonging hydrogen charging resulted in more significant degradation of the alloy microstructure,leading to deteriorated protectiveness of the surface film.This trend was further confirmed by the electrochemical measurements,which showed that the corrosion resistance of the alloy progressively worsened as the hydrogen charging time was increased.Consequently,this work provides valuable insights into the mechanisms underlying the corrosion of Ti-6Al-4V alloy under hydrogen charging conditions.

Role of methoxy and C_(α)-based substituents in electrochemical oxidation mechanisms and bond cleavage selectivity of β-O-4 lignin model compounds

In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl groups, including 2-(2-methoxyphenoxy)-1-phenylethanone, 2-(2-methoxyphenoxy)-1-phenylethanol, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanol, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanol have been selected and their electrochemical properties have been studied experimentally by cyclic voltammetry, and FT-IR spectroelectrochemistry. Combining with electrolysis products distribution analysis and density functional theory calculations, oxidation mechanisms of all six model dimers have been explored. In particular, a total effect from substituents of both para-methoxy(on the aryl ring closing to Cα) and Cα-OH on the oxidation mechanisms has been clearly observed, showing a significant selectivity on the Cα-Cβbond cleavage induced by electrochemical oxidations.

Deep learning to estimate ocean subsurface salinity structure in the Indian Ocean using satellite observations

Accurately estimating the ocean subsurface salinity structure(OSSS)is crucial for understanding ocean dynamics and predicting climate variations.We present a convolutional neural network(CNN)model to estimate the OSSS in the Indian Ocean using satellite data and Argo observations.We evaluated the performance of the CNN model in terms of its vertical and spatial distribution,as well as seasonal variation of OSSS estimation.Results demonstrate that the CNN model accurately estimates the most significant salinity features in the Indian Ocean using sea surface data with no significant differences from Argo-derived OSSS.However,the estimation accuracy of the CNN model varies with depth,with the most challenging depth being approximately 70 m,corresponding to the halocline layer.Validations of the CNN model’s accuracy in estimating OSSS in the Indian Ocean are also conducted by comparing Argo observations and CNN model estimations along two selected sections and four selected boxes.The results show that the CNN model effectively captures the seasonal variability of salinity,demonstrating its high performance in salinity estimation using sea surface data.Our analysis reveals that sea surface salinity has the strongest correlation with OSSS in shallow layers,while sea surface height anomaly plays a more significant role in deeper layers.These preliminary results provide valuable insights into the feasibility of estimating OSSS using satellite observations and have implications for studying upper ocean dynamics using machine learning techniques.