Evaluation of Holstein cows with different tongue‑rolling frequencies:stress immunity,rumen environment and general behavioural activity

Background The tongue-rolling behaviour of cows is regarded as an outward sign of stressed animals in a low welfare status.The primary aim of this observational study was to evaluate the association between the frequency of tongue-rolling behaviour and its physiological function.The secondary aim was to explore the relationship between general activities and the frequency of tongue-rolling behaviour of cows.A total of 126 scan sampling behavioural observations were collected over 7 d on 348 Holstein cows with the same lactation stage in the same barn.The tongue-rolling frequency was defined as the number of tongue-rolling observations as a percentage to the total observations per individual cow.According to their tongue-rolling frequency,the cows were grouped into the CON(no tongue-rolling),LT(frequency 1%),MT(frequency 5%),and HT(frequency 10%)groups.Six cows from each group were randomly selected for sampling.Serum samples,rumen fluid,milk yield,and background infor-mation were collected.The general behaviour data during 72 continuous hours of dairy cows,including eating time,rumination time,food time(eating time+rumination time),and lying time,were recorded by the collar sensor.Results Cortisol(P=0.012),γ-hydroxybutyric acid(P=0.008),epinephrine(P=0.030),and dopamine(P=0.047)levels were significantly higher in tongue-rolling groups than in the CON group.Cortisol levels and tongue-rolling frequency had a moderate positive correlation(linearly r=0.363).With the increase in tongue-rolling frequency,the rumen pH decreased first and then increased(P=0.013),comparing to the CON group.HT cows had significantly less food time than CON cows(P=0.035).The frequency of tongue-rolling had a moderate negative relationship with rumination time(r=-0.384)and food time(r=-0.492).Conclusions The tongue-rolling behaviour is considered as a passive coping mechanism,as the stress response in cows with high tongue-rolling frequency increased.Food intake and rumination activities were all closely related to the occurrence of tongue-rolling behaviour.

Reduced graphene oxide supported Pd-Cu-Co trimetallic catalyst:synthesis,characterization and methanol electrooxidation properties

Trimetallic palladium-copper-cobalt nanoparticles supported on reduced graphene oxide(PdCuCo/RGO)with different molar ratios of Pd,Cu and Co can be synthesized by facile chemical reduction with NaBH_4 as reductant and cetrimonium bromide as stabilizer.The morphology,structure and composition of the as-synthesized catalysts are characterized by transmission electron microscopy,X-ray diffraction and Xray photoelectron spectroscopy.The cyclic voltammetry and chronoamperometry are utilized to investigate the electrochemical activities and stabilities of the as-obtained catalysts.The results demonstrate that the PdCuCo/RGO catalyst shows superior catalytic activity and stability for methanol electrooxidation in alkaline media compared with PdCu/RGO,PdCo/RGO,and Pd/RGO catalysts.These findings suggest that the PdCuCo/RGO catalyst possesses a great potential as a promising anode catalyst for direct methanol fuel cells.

Exfoliated multi-layered graphene anode with the broadened delithiation voltage plateau below 0.5 V

The commercial graphite(CG)is the conventional anode material for lithium ion batteries(LIBs)due to its low delithiation voltage plateau(below 0.5 V)and extraordinary durability.Nevertheless,the further promotion of energy density of LIBs is restricted by the limited capacity below 0.5 V of CG.Here,based on the supercritical CO2 exfoliation technique,the production of multi-layered graphene(MLG)is achieved from the pilot scale production line.The great merit of the exfoliated MLG anode is that the voltage plateau below 0.5 V is broadened obviously as compared to those of natural graphite and CG.Additionally,no obvious lithium dendrites are observed for MLG during the lithiation process.The large delithiation capacity under the low voltage plateau of MLG is mainly benefited from the combination of Li intercalation and boundary storage mechanism,which is further confirmed by the density functional theory calculations.The LiFePO4/MLG full cell can afford the satisfactory electrochemical property with respect to the capacity,energy density and ultralong cycling stability(90%capacity retention after 500 cycles at 2 C),significantly better than that of LiFePO4/CG.Besides,this developed technique not only dedicates to producing the high-performance anode for LIBs but also opens a door for the mass production of MLG in the industrial scale.

High mass loading NiCo_(2)O_(4) with shell-nanosheet/core-nanocage hierarchical structure for high-rate solid-state hybrid supercapacitors

Rational design of advanced structure for transition metal oxides(TMOs) is attractive for achieving high-performance supercapacitors.However, it is hampered by sluggish reaction kinetics, low mass loading, and volume change upon cycling. Herein, hierarchical Ni Co_(2)O_(4) architectures with 2D-nanosheets-shell and 3D-nanocages-core(2D/3D h-NCO) are directly assembled on nickel foam via a facile one-step way.The 2D nanosheets are in-situ generated from the self-evolution of initial NCO nanospheres. This 2D/3D hierarchical structures ensure fast ion/electron transport and maintain the structural integrity to buffer the volume expansion. The 2D/3D h-NCO electrode with an ultrahigh mass loading(30 mg cm^(-2)) achieves a high areal capacity of 4.65 C cm^(-2)(equivalent to 1.29 mAh cm^(-2)) at a current density of 4 mA cm^(-2), and retains 3.7 C cm^(-2) even at 50 mA cm^(-2). Furthermore, the assembled solid-state hybrid supercapacitor yields a high volumetric energy density of 4.25 mWh cm^(-3) at a power density of 39.3 mW cm^(-3), with a high capacity retention of 92.4% after 5000 cycles. Therefore, this work provides a new insight to constuct hierarchical electrodes for energy storage application.

The Distribution and Morphology Alterations of Microfilaments and Microtubules in Mesophyll Cells and Root-Tip Cells of Wheat Seedlings under Enhanced Ultraviolet-B Radiation

The distribution and morphology alterations of microfilaments and microtubules in the mesophyll cells and root-tip cells of wheat seedlings, which had been radiated by enhanced ultraviolet-B (10.08 KJ·m-2·d-1), were examined through the confocal laser scanning microscope (Model FV1000, Olympus, Japan). Microtubule was labeled with an indirect immunofluorescence staining method, and microfilament was labeled with fluorescein isothiocyanate-phalloidin (FITC-Ph) as probes. The results indicated that microtubules in mesophyll cells, compared with the controls, would be depolymerized significantly, and dispersed randomly showing some spots or short rods in the cytoplasm, under the enhanced UV-B radiation condition. The microtubule bundles tended to be diffused, and the fluorescence intensity of that significantly decreased. The distribution pattern of microfilaments, which usually arranged parallelly in control cells, was broken up by enhanced UV-B radiation. We further investigated the distribution and morphology of microtubules in root-tip cells during every stage of cell division, and found that these aberrant phenomena of microtubules were often associated with abnormal cell division. Our findings suggested that the distribution, morphology and structure of cytoskeleton in mesophyll cells and root-tip cells of wheat seedlings would be affected by enhanced UV-B radiation, which might be related to abnormal cell division caused by enhanced UV-B radiation as an extracellular signal.

Electrochemical synthesis of FeN_(x) doped carbon quantum dots for sensitive detection of Cu^(2+) ion

A novel strategy was developed to fabricate FeNx-doped carbon quantum dots(Fe-N-CQDs)to detect Cu^(2+) ions selectively as a fluorescence probe.The Fe-N-CQDs were synthesized by an efficient electrolysis of a carbon cloth electrode,which was coated with monoatomic ironanchored nitrogen-doped carbon(Fe-N-C).The obtained Fe-N-CQDs emitted blue fluorescence and possessed a quantum yield(QY)of 7.5%.An extremely wide linear relationship between the Cu^(2+) concentration and the fluorescence intensity was obtained in the range from 100 nmol L^(-1) to 1000 nmol L^(-1)(R^(2)=0.997),and the detection limit was calculated as 59 nmol L^(-1).Moreover,the Fe-N-CQDs demonstrated wide range pH compatibility between 2 and 13 due to the coordination between pyridine nitrogen and Fe^(3+),which dramatically reduced the affection of the protonation and deprotonation process between H^(+) and Fe-N-CQDs.It is notable that the Fe-N-CQDs exhibited a rapid response in Cu^(2+) detection,where stable quenching can be completed in 7 s.The mechanism of excellent selective detection of Cu^(2+) was revealed by energy level simulation that the LUMO level of Fe-N-CQDs(-4.37 eV)was close to the redox potential of Cu^(2+),thus facilitating the electron transport from Fe-N-CQDs to Cu^(2+).

Transcriptomic and proteomic studies of condylar ossification of the temporomandibular joint in porcine embryos

Background:The ossification mechanism of the temporomandibular joint(TMJ)condyle remains unclear in human embryo.The size and structure of TMJ,shape of articular disc and the characteristics of omnivorous chewing in the pig are similar to those of humans.The pig is an ideal animal for studying the mechanism of ossification of the TMJ condyle during the embryonic period.Method:In a previous study by our group,it was found that there was no condylar ossification on embryonic day(E)45,but the ossification of condyle occurred between E75 and E90.In this study,a total of 12 miniature pig embryos on E45 and E85 were used.Six embryos were used for tissue sections(3 in each group).The remaining six embryos were used for transcriptomic and proteomic studies to find differential genes and proteins.The differentially expressed genes in transcriptome and proteomic analysis were verified by QPCR.Results:In total,1592 differential genes comprising 1086 up-regulated genes and 506 down-regulated genes were screened for fold changes of≥2 to≤0.5 between E45 and E85.In the total of 4613 proteins detected by proteomic analysis,there were 419 differential proteins including 313 up-regulated proteins and 106 down-regulated proteins screened for fold changes of≥2 to≤0.5 between E45 and E85.A total of 36 differential genes differing in both transcriptome and proteome analysis were found.QPCR analysis showed that 14 of 15 selected genes were consistent with transcriptome analysis.Conclusion:Condylar transcriptome and proteomic analysis during the development of TMJ in miniature pigs revealed the regulatory genes/proteins of condylar ossification.

Laser ablation mechanism and performance of glass fiber-reinforced phenolic composites:An experimental study and dual-scale modelling

Both experimental and simulation approaches were employed to investigate the laser ablation mechanism and performances of Glass Fiber Reinforced Phenolic Composites(GFRP).During the ablation process,the difference in thermal conductivities of the glass fibers and the resin matrix as well as their discrepant physical and chemical reactions form a conical ablation morphology.The formation of a residual carbon layer effectively mitigates the ablation rate in the thickness direction.A higher power density results in a faster ablation rate,while a longer irradiation time leads to a larger ablation pit diameter.To account for the variation in thermal conductivity between the fiber and resin,a macro-mesoscale model was developed to differentiate the matrix from the fiber components.Finite element analysis revealed that laser irradiation leads to phenolic decomposition,glass fiber melting vaporization,and residual carbon skeleton evaporation.The dual-scale model exhibits precise prediction capabilities concerning the laser ablation process of GFRP,and its accuracy is confirmed through the comparison of simulation and experimental results for the GFRP laser ablation process.This model provides a feasible method for performance evaluation and lifetime prediction of GFRP subjected to continuous wave laser irradiation.

Kinetics of methanol steam reforming over COPZr-2 catalyst

The COPZr-2 catalyst, which was prepared in our prophase research, showed good catalytic performance in methanol steam reforming reaction. In this article, the best one was chosen as an example to study the reaction kinetics of methanol steam reforming over this type of catalyst. First, the effects of methanol conversion to outlet CO2 and methanol conversion to outlet CO on methanol pseudo contact time W/FMeOH were investigated. Then by applying the reaction route that methanol direct reforming （DR） and methanol decomposition （DE） were carried out in parallel, the reaction kinetic model with power function type was established. And the parameters for the model were estimated using a non-linear regression program which computed weighted least squares of the defined objects function. Finally, the kinetic model passed the correlation test and the F-test.

A facile preparation of hausmannite as a high-performance catalyst for toluene combustion

Mesoporous transition metal oxide catalysts are well-used in the elimination of volatile organic compounds.In this study,we developed an efficient method for the preparation of mesoporous-Mn_(3)O_(4)(mMn_(3)O_(4))without the use of templates or surfactants.In this method,KCl protects oxygen defects on the surface of fresh Mn_(3)O_(4) crystallites.m-Mn_(3)O_(4) shows higher ameliorative catalytic activity than bulk-Mn_(3)O_(4)(b-Mn_(3)O_(4)) and calcined-Mn_(3)O_(4)(c-Mn_(3)O_(4)),achieving toluene catalytic oxidation of T_(10) and T_(90)(the temperature at a conversion rate of about 10%and 90%)at 191℃and 230℃,respectively(WHSV=40,000 ml·g^(-1)·h^(-1)).Based on various characterizations,the prepared m-Mn_(3)O_(4)has large specific surface area and abundant oxygen defects,and thus can provide more surface active sites,which give it superior toluene combustion activity.

Mo-doped CoP nanoparticles anchored on porous Co-N-C framework as an efficient bifunctional electrocatalyst for pH-universal water splitting

Designing highly active and stable noble-metal-free electrocatalysts for water splitting over a wide pH range is critical yet remains significantly challenging.In this work,Mo-doped CoP nanoparticles(Mo-CoP)supported and enwrapped by porous single-atomic-Co doped carbon framework(Co-N-C)were designed and prepared by a simple one-pot pyrolysis method.The Mo-CoP/Co-N-C electrocatalyst exhibits superior performance with low overpotentials of only 45 mV for hydrogen evolution reaction(HER)and 201 mV for oxygen evolution reaction(OER)in 1 M KOH at 10 mA cm^(-2)current density.Such excellent catalytic activity can be ascribed to enhanced intrinsic activity,large surface area,and highly exposed active sites.Meanwhile,an extremely small overpotential of only 250 mV is required for a large current density of 500 mA cm^(-2)in HER,which exceeds the performance of benchmark 10%Pt/C.Besides,Mo-CoP/Co-N-C also exhibits superior HER performance in acidic and neutral mediums,with overpotentials of only 41 and 98 mV in 0.5 M H_(2)SO_(4),and 1 M PBS,respectively,thus achieving efficient water splitting at a wide pH range.The long-term stabilities are guaranteed with no significant decline of catalytic activities for more than 24 h in all electrolytes,which can be ascribed to the carbon layer encapsulation structure.Addition-ally,in overall water splitting,the electrocatalytic cell consisting of the as-synthesized Mo-CoP/Co-N-C only requires a cell voltage of 1.611 V at 100 mA cm^(-2)with excellent stability,exceeding that of the benchmark Pt/C||RuO(2) couple(1.645 V at 100 mA cm^(-2)).This work not only presents a highly efficient electrocatalyst for pH-universal water splitting but also provides a new perspective for the design and construction of transition metal catalysts with excellent stability.

Biodegradable interference distraction implant:a promising replacement for conventional implant in patients with insufficient alveolar bone height

Background Dental implants have been widely used in the last few decades.However,patients with insufficient bone height need reconstructive surgeries before implant insertion.Distraction implant(Dl)has been invented to simplify the treatment procedure,but the shortcomings of Dl have limited its clinical use.We introduced biodegradable polyester to a novel Dl,called biodegradable interference distraction implant(BIDI).The purpose of this study was to assess the radiological,histological,and biomechanical properties of BIDI in animal models.Methods BIDIs were manufactured and inserted into the atrophied mandibles of 6 dogs.

Co-planted barnyardgrass reduces rice yield by inhibiting plant above-and belowground-growth during post-heading stages

Barnyardgrass (Echinochloa spp.) is the most common noxious weed in rice paddies as it inhibits rice growth and reduces grain yield.To date,little information is available on above-and belowgroundgrowth changes in rice due to neighboring barnyardgrass.This study aimed to investigate the changes in root traits and shoot growth of rice when it is grown with different kinds of barnyardgrass.Japonica rice plants (var.Nanjing 9108) were co-cultured with two varieties of Echinochloa crusgalli (L.) Beauv.(EP,var.mitis (pursh) Petern;EH,var.zelayensis (H.B.K.) Hitchc),and E.colonum (L.) Link (EL) in the field in 2017 and 2018.Four treatments included control (i.e.,weed free rice plants) and co-cultures with each of three barnyardgrasses (EP,EH,and EL).The results revealed that EP,EH,and EL treatments significantly reduced rice grain yields by 30.6%–36.2%,42.5%–46.5%,and 10.6%–14.3%,respectively.Shoot growth including shoot dry weight,leaf photosynthetic rate,zeatin (Z) and zeatin riboside (ZR) in grains,and activities of key enzymes involved in sucrose-to-starch conversion in grains and root traits,such as length density,root dry weight,total absorbing surface area,active absorption surface area,oxidation activity,and Z+ZR contents in roots were dramatically reduced during post-heading stages of rice when grown with the three kinds of barnyardgrass.Moreover,above-mentioned rice shoot growth indices were strongly and positively correlated with root traits.These results suggested the decrease in rice shoot growth and root traits during post-heading stages contributes to the reduction in the rice yield when it grows with barnyardgrass neighbors.

Scalable preparation of water-soluble ink of few-layered WSe2 nanosheets for large-area electronics

Few-layer two-dimensional(2D)semiconductor nanosheets with a layer-dependent band gap are attractive building blocks for large-area thin-film electronics.A general approach is developed to fast prepare uniform and phase-pure 2HWSe2 semiconducting nanosheets at a large scale,which involves the supercritical carbon dioxide(SC-CO2)treatment and a mild sonication-assisted exfoliation process in aqueous solution.The as-prepared 2H-WSe2 nanosheets preserve the intrinsic physical properties and intact crystal structures,as confirmed by Raman,x-ray photoelectron spectroscopy(XPS),and scanning transmission electron microscope(STEM).The uniform 2H-WSe2 nanosheets can disperse well in water for over six months.Such good dispersivity and uniformity enable these nanosheets to self-assembly into thickness-controlled thin films for scalable fabrication of large-area arrays of thin-film electronics.The electronic transport and photoelectronic properties of the field-effect transistor based on the self-assembly 2H-WSe2 thin film have also been explored.

Amorphous Sn modified nitrogen-doped porous carbon nanosheets with rapid capacitive mechanism for highcapacity and fast-charging lithium-ion batteries

Sn-based materials are considered as a kind of potential anode materials for lithium-ion batteries(LIBs)owing to their high theoretical capacity.However,their use is limited by large volume expansion deriving from the lithiation/delithiation process.In this work,amorphous Sn modified nitrogen-doped porous carbon nanosheets(ASnNPCNs)are obtained.The synergistic effect of amorphous Sn and high edge-nitrogendoped level porous carbon nanosheets provides ASn-NPCNs with multiple advantages containing abundant defect sites,high specific surface area(214.9 m^(2)·g^(−1)),and rich hierarchical pores,which can promote the lithium-ion storage.Serving as the LIB anode,the as-prepared ASn-NPCNs-750 electrode exhibits an ultrahigh capacity of 1643 mAh·g^(−1) at 0.1 A·g^(−1),ultrafast rate performance of 490 mAh·g^(−1) at 10 A·g^(−1),and superior long-term cycling performance of 988 mAh·g^(−1) at 1 A·g^(−1) after 2000 cycles with a capacity retention of 98.9%.Furthermore,the in-depth electrochemical kinetic test confirms that the ultrahigh-capacity and fast-charging performance of the ASn-NPCNs750 electrode is ascribed to the rapid capacitive mechanism.These impressive results indicate that ASn-NPCNs-750 can be a potential anode material for high-capacity and fast-charging LIBs.

Miura origami based reconfigurable polarization converter for multifunctional control of electromagnetic waves

Polarization is one of the basic characteristics of electromagnetic(EM)waves,and its flexible control is very important in many practical applications.At present,most of the multifunction polarization metasurfaces are electrically tunable based on PIN and varactor diodes,which are easy to operate and have strong real-time performance.However,there are still some problems in them,such as few degrees of freedom of planar structure control,complex circuit,bulky sample,and high cost.In view of these shortcomings,this paper proposes a Miura origami based reconfigurable polarization conversion metasurface for multifunctional control of EM waves.The interaction between the electric dipoles is changed by adjusting the folding angleθ,thereby tuning the operating frequency of the polarization conversion and the polarization state of the reflected wave.This mechanical control method brings more degrees of freedom to manipulate EM waves.And the processed sample is with lightweight and low cost.To verify the performance of the proposed origami polarization converter,a Miura origami structure loaded with metal split rings is designed and fabricated.The operating frequency of the structure can be tuned in different folding states.In addition,by controlling the folding angleθ,linear-to-linear and linear-to-circular polarization converters can be realized at different folding states.The proposed Miura origami polarization conversion metasurface provides a new idea for reconfigurable linear polarization conversion and multifunctional devices.

Magnetic coupling engineered porous dielectric carbon within ultralow filler loading toward tunable and high-performance microwave absorption

Developing microwave absorption(MA)materials with satisfied comprehensive performance is a great challenge for tackling severe electromagnetic pollution.In particular,the magnetic component/carbon hybrids absorbers always suffer from high filler loading.Herein,we propose a feasible strategy to construct hierarchical porous carbon with tightly embedded Ni nanoparticles(Ni@NPC).These highly dispersed Ni nanoparticles produce strong magnetic coupling networks to enhance magnetic loss abilities.Moreover,the interconnected hierarchical dielectric carbon network affords favorable dipolar/interfacial polarization,conduction loss,multiple reflection and scattering.Impressively,with an ultralow filler loading of 5 wt.%,the resultant Ni@NPC/paraffin composite achieves an excellent MA performance with a minimum reflection loss of as high as-72.4 dB and a broad absorption bandwidth of 5.0 GHz.This capability outperforms most current magnetic-dielectric hybrids counterparts.Furthermore,the MA capacity can be easily tuned with adjustments in thickness,content and type of magnetic material.Thus,this work opens up new avenues for the development of high-performance and lightweight MA materials.

Conductive photo-thermal responsive bifunctional hydrogel system with self-actuating and self-monitoring abilities

Despite enormous efforts in actuators,most researches are only limited to various actuation behaviors and demonstrations of soft materials.It has not yet been reported to capture and monitor its movement status in an invisible environment.Therefore,it is of great significance to develop a self-sensing and self-actuating dual-function hydrogel actuator system to realize real-time monitoring.Here,we report a bifunctional hydrogel system with self-actuating and self-monitoring abilities,which combines the functions of photothermal actuation and electrical resistance sensing into a single material.The bilayer tough conductive hydrogel synthesized by unconventional complementary concentration recombination and cryogenic freezing technique presents a dense conductive network and high-porosity structure,achieving high toughness at 190.3 kPa of tensile strength,high stretchability(164.3%strain),and the toughness dramatically(1,471.4 kJ·m^(−3)).The working mechanism of the monitoring and self-sensing system is accomplished through the integrated monitoring device of surface temperature–bending angle–electron current,to solve the problem of not apperceiving actuator motion state when encountering obstacles in an invisible environment.We demonstrated for the first time a photothermal actuator’s motion of a football player and goalkeeper to finish the penalty and a soft actuator hand,which can achieve the action of sticking to grab and release under photo-thermal actuation.When connected to the control closed circuit,the actuator realized closed-loop monitoring and sensing feedback.The development of bifunctional hydrogel systems may bring new opportunities and ideas in the fields of material science,circuit technology,sensors,and mechanical engineering.

Template-mediated strategy to regulate hierarchically nitrogen-sulfur co-doped porous carbon as superior anode material for lithium capacity

Considering its rapid lithiation/delithiation process and robust capacitive energy storage,hierarchical porous carbon is regarded as a promising candidate for lithium-ion batteries(LIBs).However,it remains a great challenge to construct a porous structure and prevent structure stacking for carbon-based materials.Herein,a templatemediated approach is developed to synthesize hierarchical nitrogen-sulfur co-doped porous carbon(NSPC)using low-cost asphalt precursors.The strategy for synthesis uses g-C_(3)N_(4) and NaHCO_(3) as gaseous templates and NaCl as a solid template,which causes the formation of hierarchical porous carbon with a high specific surface area.The resultant porous structure and nitrogen-doping process can prevent the aggregation of nanosheets,maintain the structural stability upon cycling,and achieve rate-capable lithium storage.Serving as a LIBs anode,reversible specific capacities of the NSPC24 electrode reach 788 and 280 mAh·g^(-1) at 0.1 and 1 A·g^(-1),respectively.Furthermore,its specific capacity remains at 830 mAh·g^(-1) after 115 cycles at 0.1 A·g^(-1).Even after 500 cycles,high specific capacities of 727 mAh·g^(-1) at 0.5 A·g^(-1) and 624 mAh·g^(-1) at 1 A·g^(-1) are achieved,demonstrating excellent cycling performance.The gas-solid bifunctional template-mediated approach can guide the design of porous materials very well,meanwhile realizing the high value-added utilization of asphalt.

Strong and Superhydrophobic Wood with Aligned Cellulose Nanofibers as a Waterproof Structural Material

Lightweight structural materials are important for the energy efficiency of applications,particularly those in the building sector.Here,inspired by nature,we developed a strong,superhydrophobic,yet lightweight material by simple in situ growth of nano-SiO2 and subsequent densification of the wood substrate.In situ generation of SiO2 nanoparticles both inside the wood channels and on the wood surfaces gives the material superhydrophobicity,with static and dynamic contact angles of 159.4°and 3°,respectively.Densification of the wood to remove most of the spaces among the lumen and cell walls results in a laminated,dense structure,with aligned cellulose nanofibers,which in turn contributes to a high mechanical strength up to 384.2 MPa(7-times higher than natural wood).Such treatment enables the strong and superhydrophobic wood(SH-Wood)to be stable and have excellent water,acid,and alkaline resistance.The high mechanical strength of SH-Wood combined with its excellent structural stability in harsh environments,as well its low density,positions the strong and superhydrophobic wood as a promising candidate for strong,lightweight,and durable structural materials that could potentially replace steel.