Optimization of the in-situ growth conditions based on a novel photo-microcalorimeter for the sustainable cultivation of photosynthetic microorganisms

Despite the great potential of photosynthetic microbes in the production of renewable fuels,value-adding chemicals,and water treatment,etc.,commercial utilization of them is significantly hindered by the lack of techniques to accurately monitor the thermodynamic and kinetic characteristics of the in-situ growth of microbes under controlled light illumination for optimal cultivation.Herein,we demonstrated that a newly developed highly sensitive photo-microcalorimetric system successfully captured the impacts of the light wavelength and strength on the thermodynamic and kinetic parameters of the in-situ growth of Rhodopseudomonas palustris,a representative photosynthetic microorganism.To our best knowledge,this is the first time that highly precise microcalorimetry is employed to monitor exam the in-situ growth of photosynthetic microorganisms under controllable photo illumination.We envision this technique can help for the optimization of the growth conditions of photosynthetic microorganisms for scale-up applications.

Probing the Nucleation and Growth Kinetics of Bismuth Nanoparticles via In-situ Transmission Electron Microscopy

The nucleation and growth mechanism of nanoparticles is an important theory,which can guide the preparation of nanomaterials.However,it is still lacking in direct observation on the details of the evolution of intermediate state structure during nucleation and growth.In this work,the evolution process of bismuth nanoparticles induced by electron beam was revealed by in-situ transmission electron microscopy(TEM)at atomic scale.The experimental results demonstrate that the size,stable surface and crystallographic defect have important influences on the growth of Bi nanoparticles.Two non-classical growth paths including single crystal growth and polycrystalline combined growth,as well as,corresponding layer-by-layer growth mechanism along{012}stable crystal plane of Bi nanoparticles with dodecahedron structure were revealed by in-situ TEM directly.These results provide important guidance and a new approach for in-depth understanding of the nucleation and growth kinetics of nanoparticles.

Stiffness-tunable biomaterials provide a good extracellular matrix environment for axon growth and regeneration

Neuronal growth, extension, branching, and formation of neural networks are markedly influenced by the extracellular matrix—a complex network composed of proteins and carbohydrates secreted by cells. In addition to providing physical support for cells, the extracellular matrix also conveys critical mechanical stiffness cues. During the development of the nervous system, extracellular matrix stiffness plays a central role in guiding neuronal growth, particularly in the context of axonal extension, which is crucial for the formation of neural networks. In neural tissue engineering, manipulation of biomaterial stiffness is a promising strategy to provide a permissive environment for the repair and regeneration of injured nervous tissue. Recent research has fine-tuned synthetic biomaterials to fabricate scaffolds that closely replicate the stiffness profiles observed in the nervous system. In this review, we highlight the molecular mechanisms by which extracellular matrix stiffness regulates axonal growth and regeneration. We highlight the progress made in the development of stiffness-tunable biomaterials to emulate in vivo extracellular matrix environments, with an emphasis on their application in neural repair and regeneration, along with a discussion of the current limitations and future prospects. The exploration and optimization of the stiffness-tunable biomaterials has the potential to markedly advance the development of neural tissue engineering.

Telencephalic stab wound injury induces regenerative angiogenesis and neurogenesis in zebrafish:unveiling the role of vascular endothelial growth factor signaling and microglia

After brain damage,regenerative angiogenesis and neurogenesis have been shown to occur simultaneously in mammals,suggesting a close link between these processes.However,the mechanisms by which these processes interact are not well understood.In this work,we aimed to study the correlation between angiogenesis and neurogenesis after a telencephalic stab wound injury.To this end,we used zebrafish as a relevant model of neuroplasticity and brain repair mechanisms.First,using the Tg(fli1:EGFP×mpeg1.1:mCherry)zebrafish line,which enables visualization of blood vessels and microglia respectively,we analyzed regenerative angiogenesis from 1 to 21 days post-lesion.In parallel,we monitored brain cell proliferation in neurogenic niches localized in the ventricular zone by using immunohistochemistry.We found that after brain damage,the blood vessel area and width as well as expression of the fli1 transgene and vascular endothelial growth factor(vegfaa and vegfbb)were increased.At the same time,neural stem cell proliferation was also increased,peaking between 3 and 5 days post-lesion in a manner similar to angiogenesis,along with the recruitment of microglia.Then,through pharmacological manipulation by injecting an anti-angiogenic drug(Tivozanib)or Vegf at the lesion site,we demonstrated that blocking or activating Vegf signaling modulated both angiogenic and neurogenic processes,as well as microglial recruitment.Finally,we showed that inhibition of microglia by clodronate-containing liposome injection or dexamethasone treatment impairs regenerative neurogenesis,as previously described,as well as injury-induced angiogenesis.In conclusion,we have described regenerative angiogenesis in zebrafish for the first time and have highlighted the role of inflammation in this process.In addition,we have shown that both angiogenesis and neurogenesis are involved in brain repair and that microglia and inflammation-dependent mechanisms activated by Vegf signaling are important contributors to these processes.This study paves the way for a better understanding of the effect of Vegf on microglia and for studies aimed at promoting angiogenesis to improve brain plasticity after brain injury.

Transforming growth factor-beta 1 enhances discharge activity of cortical neurons

Transforming growth factor-beta 1(TGF-β1)has been extensively studied for its pleiotropic effects on central nervous system diseases.The neuroprotective or neurotoxic effects of TGF-β1 in specific brain areas may depend on the pathological process and cell types involved.Voltage-gated sodium channels(VGSCs)are essential ion channels for the generation of action potentials in neurons,and are involved in various neuroexcitation-related diseases.However,the effects of TGF-β1 on the functional properties of VGSCs and firing properties in cortical neurons remain unclear.In this study,we investigated the effects of TGF-β1 on VGSC function and firing properties in primary cortical neurons from mice.We found that TGF-β1 increased VGSC current density in a dose-and time-dependent manner,which was attributable to the upregulation of Nav1.3 expression.Increased VGSC current density and Nav1.3 expression were significantly abolished by preincubation with inhibitors of mitogen-activated protein kinase kinase(PD98059),p38 mitogen-activated protein kinase(SB203580),and Jun NH2-terminal kinase 1/2 inhibitor(SP600125).Interestingly,TGF-β1 significantly increased the firing threshold of action potentials but did not change their firing rate in cortical neurons.These findings suggest that TGF-β1 can increase Nav1.3 expression through activation of the ERK1/2-JNK-MAPK pathway,which leads to a decrease in the firing threshold of action potentials in cortical neurons under pathological conditions.Thus,this contributes to the occurrence and progression of neuroexcitatory-related diseases of the central nervous system.

Activation of adult endogenous neurogenesis by a hyaluronic acid collagen gel containing basic fibroblast growth factor promotes remodeling and functional recovery of the injured cerebral cortex

The presence of endogenous neural stem/progenitor cells in the adult mammalian brain suggests that the central nervous system can be repaired and regenerated after injury.However,whether it is possible to stimulate neurogenesis and reconstruct cortical layers II to VI in non-neurogenic regions,such as the cortex,remains unknown.In this study,we implanted a hyaluronic acid collagen gel loaded with basic fibroblast growth factor into the motor cortex immediately following traumatic injury.Our findings reveal that this gel effectively stimulated the proliferation and migration of endogenous neural stem/progenitor cells,as well as their differentiation into mature and functionally integrated neurons.Importantly,these new neurons reconstructed the architecture of cortical layers II to VI,integrated into the existing neural circuitry,and ultimately led to improved brain function.These findings offer novel insight into potential clinical treatments for traumatic cerebral cortex injuries.

In-situ growth of gold nanoparticles on electrospun flexible multilayered PVDF nanofibers for SERS sensing of molecules and bacteria

Plasmonic surface of flexible multilayered nanofibers possesses special superiority for the surface-enhanced Raman scattering(SERS)sensing of molecules and microbial cells.However,the fabrication of flexible plasmonic nanofibers with high sensitivity and reproducibility is difficult.Herein,we report a smart strategy for fabricating flexible plasmonic fibers,in which compact and homogeneous gold nanoparticles(Au NPs)are in-situ grown on the high-curvature surface of multilayered fibers of electrospun polyvinylidene fluoride(PVDF).Firstly,the surface of PVDF fibers is changed electrically,and Au seeds are deposited on the surface of PVDF fibers using electrostatic driving force.Secondly,a stable AuI_(4)−complex is formed employing coordination between I−and AuCl4−ions,which could decrease the reduction potential of AuCl4−and restrain the self-nucleation,and then the reduction reaction of AuI4−is initiated by introducing PVDF@Au seeds to pull down the barrier of potential energy.Finally,in-situ growth of AuNPs is generated on the high-curvature surface of PVDF nanofibers,and large-scale hotspots are generated by adjacent AuNPs coupling in the three-dimensional(3D)space of multilayered fibers.Membrane of PVDF@Au nanofibers also realizes the sensitive detection of thiram molecules(low limit of detection of 0.1 nM)and good reproducibility(relative standard deviation of 10.6%).Meanwhile,due to the multilayered construction of PVDF@Au nanofibers,a valid SERS signal on 3D surface of bacteria could be generated.3D distribution of hotspots on multilayered PVDF@Au nanofibers gives a clear advantage for SERS sensing of organic molecules and microbial cells.

In-situ growth of polypyrrole on aramid nanofibers for electromagnetic interference shielding films with high stability

Flexible electromagnetic interference(EMI)shielding films with high stability have shown promising prospect in harsh working conditions such as military,communication,and special protection fields.Herein,flexible aramid nanofibers@polypyrrole(ANF@PPy)films with high stability were easily achieved by the in-situ growth of PPy on the surface of ANF and the subsequent pressured-filtration film-forming process.When the amount of pyrrole(Py)monomer is 40μL,the ANF@PPy(AP40)film exhibited excellent EMI shielding performance with shielding effectiveness(SE)of 41.69 dB,tensile strength of 96.01 MPa,and fracture strain of 21.95%at the thickness of 75.76μm.Particularly,the anticipated EMI shielding performance can be maintained even after being heated at 200℃in air,soaked in 3.5%NaCl solution,repeated folding for one million times,or burned directly,indicating superior environmental durability in harsh conditions.Therefore,it is believed that the ANF@PPy films with high stability offer a facile solution for practical protection for high-performance EMI shielding applications.

In-situ growth of hybrid NaTi8O13/NaTiO2 nanoribbons on layered MXene Ti3C2 as a competitive anode for high-performance sodium-ion batteries

In the work,we successfully explore a two-step hydrothermal method for scalable synthesis of the hybrid sodium titanate(NaTi8O13/NaTiO2) nanoribbons well in-situ formed on the multi-layered MXene Ti3C2(designed as NTO/Ti3C2).Benefiting from the inherent structural and componential superiorities,the resulted NTO/Ti3C2 composite exhibits long-duration cycling stability and superior rate behaviors when evaluated as a hybrid anode for advanced SIBs,which delivers a reversible and stable capacity of^82 mAh/g even after 1900 cycles at 2000 mA/g for SIBs.

In-situ growth of V2O5 flower-like structures on ceramic tubes and their trimethylamine sensing properties

V2O5 flower-like structures assembled by thin nanosheets were in-situ growth on ceramic tubes by hydrothermal process.The structural characterization indicates that V2O5 flower-like structures is orthogonal diamond phase,which entirely covered on the surface of ceramic tubes.TMA sensing measured results revealed that the sensor based on V2O5 flower-like structures exhibited fast reversible and response,good selectivity to TMA and good stability at 200℃.The good sensing performance may be ascribed to flower-like structure s and directly growth sensing film on the ceramic tube without structure damage.Our works give a simple in-situ growth flower-like structures route on sensing device,which exhibits potential application for detecting trace amounts of TMA gas.

Growth mechanism of reinforcements in in-situ synthesized (TiB+TiC)/Ti composites

The growth mechanism of reinforcement in in situ synthesized (TiB+TiC)/Ti composites was investigated. The results show that reinforcements nucleate and grow in a way of dissolution precipitation. The morphologies of reinforcements are closely related to the solidification paths and crystal structure of reinforcements. TiB, as a reinforcement, is liable to grow along [010] direction and forms in short fibre shape due to its B27 structure, whereas primary TiC is liable to form composition undercooling and grow in dendritic shape. TiC phases precipitated in binary eutectic and ternary eutectic reactions grow in equiaxial shape. The addition of aluminum element refines TiB and TiC particles, and makes TiC reinforcements grow into the equiaxial particles easily. The addition of graphite adjusts the solidification paths and forms more TiC with dendritic shape. [

In-situ growth and photoluminescence of β-Ga_2O_3 cone-like nanowires on the surface of Ga substrates

β-Ga2O3 cone-like nanowires have been in-situ grown on the surface of gallium grains and films by heating gallium substrates at 750-1000℃ for 2h in air.The controllable synthesis of β-Ga2O3 nano-wires with different diameters and lengths was achieved by adjusting the heating temperature and time.The as-synthesized products were characterized by means of X-ray diffraction,scanning electron mi-croscopy and transmission electron microscopy.The results showed that the β-Ga2O3 nanowires are single crystalline with a monoclinic structure and have a controllable diameter and length in the range of 30-100nm and 0.5-1.5μm,respectively.A possible mechanism was also proposed to account for the formation of β-Ga2O3 cone-like nanowires.Photoluminescence spectra of the β-Ga2O3 nanowires obtained at different temperatures were measured at room temperature,and a strong blue photolumi-nescence with peaks at 430 and 460nm and a weak red photoluminescence with peak at 713nm were observed.The blue light emission intensity decreases with increasing the reaction temperature,how-ever,the red light emission intensity hardly changes.The blue and red light emissions originate from the recombination of an electron on an oxygen vacancy with a hole on a gallium-oxygen vacancy pair and the nitrogen dopants,etc.,respectively.

Three-dimensional （3D） interconnected networks fabricated via in-situ growth of N-doped graphene/ carbon nanotubes on Co-containing carbon nanofibers for enhanced oxygen reduction

The strategy of combining highly conductive frameworks with abundant active sites is desirable in the preparation of alternative catalysts to commercial Pt/C for the oxygen reduction reaction （ORR）. In this study, N-doped graphene （NG） and carbon nanotubes （CNT） were grown in-situ on Co-containing carbon nanofibers （CNF） to form three-dimensional （3D） interconnected networks. The NG and CNT bound the interlaced CNF together, facilitating electron transfer and providing additional active sites. The 3D interconnected fiber networks exhibited excellent ORR catalytic behavior with an onset potential of 0.924 V （vs. reversible hydrogen electrode） and a higher current density than Pt/C beyond 0.720 V. In addition, the hybrid system exhibited superior stability and methanol tolerance to Pt/C in alkaline media. This method can be extended to the design of other 3D interconnected network architectures for energy storage and conversion applications.

In-situ growth of flexible 3D hollow tubular Cu_(2)S nanorods on Cu foam for high electrochemical performance supercapacitor

For pursing high-performance supercapacitors,both of the design strategy and structural characteristic of electrode materials are crucial.Herein,we report the in-situ growth of flexible self-assembled 3D hollow tubular Cu_(2)S nanorods on Cu foam substrate(Cu_(2)S@Cu).The Cu substrate is simultaneously acted as a copper source and a collector,which reduces the contact resistance.Moreover,the highly ordered 3D unique structure increases the redox reactive sites and enhances the ion transmission effectively,resulting in greatly improved electrochemical performance.Based on the Cu_(2)S@Cu electrode,the supercapacitor exhibits high areal capacitance of 1000 mF cm^(-2) at a current density of 2 mA cm^(-2),and great cycle stability,maintaining 96.9% capacitance after 10,000 cycles.Furthermore,the supercapacitor also shows an excellent flexibility with no significant decrease in the twisting or bending state.The capacity retention rates are 99.8% and 86.1%,respectively,and finally recover to 99.3%,confirming its great potential in practical application for portable electronic devices.

In-situ growth of carbon nanotubes on ZnO to enhance thermoelectric and mechanical properties

As a high-temperature thermoelectric(TE)material,ZnO offers advantages of non-toxicity,chemical stability,and oxidation resistance,and shows considerable promise as a true ready-to-use module under air conditions.However,poor electrical conductivity and high thermal conductivity severely hinder its application.Carbon nanotubes(CNTs)are often used as a reinforcing phase in composites,but it is difficult to achieve uniform dispersion of CNTs due to van der Waals forces.Herein,we developed an effective in-situ growth strategy of homogeneous CNTs on ZnO nanoparticles by exploiting the chemical vapor deposition(CVD)technology,in order to improve their electrical conductivity and mechanical properties,as well as reducing the thermal conductivity.Meanwhile,magnetic nickel(Ni)nanoparticles are introduced as catalysts for promoting the formation of CNTs,which can also enhance the electrical and thermal transportation of ZnO matrices.Notably,the electrical conductivity of ZnO is significantly boosted from 26 to 79 S·cm^(−1) due to the formation of dense and uniform conductive CNT networks.The lattice thermal conductivity(κ_(L))is obviously declined by the intensification of phonon scattering,resulting from the abundant grain boundaries and interfaces in ZnO-CNT composites.Importantly,the maximum dimensionless figure of merit(zT)of 0.04 at 800 K is obtained in 2.0%Ni-CNTs/ZnO,which is three times larger than that of CNTs/ZnO prepared by traditional ultrasonic method.In addition,the mechanical properties of composites including Vickers hardness(HV)and fracture toughness(K_(IC))are also reinforced.This work provides a valuable reference for dispersing nano-phases in TE materials to enhance both TE and mechanical properties.

基于FP-growth算法的交通事故数据关联规则挖掘研究

为了探寻多种事故影响因素共同作用下诱发交通事故的某种规律以及各因素间的关系,本文采用FP-growth算法对收集到的交通事故数据进行分析研究,挖掘其中的潜在价值信息,找出事故发生的原因,根据分析结果给相关部门提出建议,帮助城市交通管理者制定更有效的管理措施,以达到降低交通事故发生频率的目的。

In-situ Growth of Carbon Nanosheets Intercalated with TiO_(2) for Improving Electrochemical Performance and Stability of Lithium-ion Batteries

In situ growth of carbon nanomaterials on active substance is a very favorable strategy for the preparation of electrode in lithium-ion batteries with excellent electrochemical performance and high stability.Small-sized TiO_(2) nanoparticles intercalated into carbon nanosheets(CNS@TiO_(2)SNP-600)were successfully synthesized via in-situ polymerization-carbonization method,utilizing layered H_(2)Ti_(4)O_(9)(HTO)as template and benzidine as carbon source.The morphology and size of TiO_(2) are greatly influenced by carbonization temperature.The coin cell with the CNS@TiO_(2)SNP-600 electrode demonstrates a discharge specific capacity of 430.4 mAh·g^(-1) at a current density of 0.1 A·g^(-1),and the capacity retention rate is 88.1%after 100 cycles;and it also displays a high discharge specific capacity of 101.8 mAh·g^(-1) at a high current density of 12.8 A·g^(-1).The excellent electrochemical performances can be ascribed to the capacitance effect originated from the intercalated structure of in-situ grown CNS and TiO_(2) nanoparticles.We believe this type of materials can be widely used in the lithium-ion batteries and other related green chemical fields.

IN-SITU OBSERVATION OF THERMAL FATIGUE CRACK GROWTH IN STEEL 3Cr2W8V

The growing process of thermal fatigue cracking,in steel 3Cr2WSV was observed under desk SEM fitted with sell-made minisized device for thermal faligue test.Before the growing of thermal fatigue crack,the main crack tip reveals to blunt firstly,and some holes and uncontinuous microcraeks occur in front of it.The growth is developed by bridging of main crack together with holes and microcracks.

Solute drag-controlled grain growth in magnesium investigated by quasi in-situ orientation mapping and level-set simulations

Critical properties of metallic materials,such as the yield stress,corrosion resistance and ductility depend on the microstructure and its grain size and size distribution.Solute atoms that favorably segregate to grain boundaries produce a pinning atmosphere that exerts a drag pressure on the boundary motion,which strongly affects the grain growth behavior during annealing.In the current work,the characteristics of grain growth in an annealed Mg-1 wt.%Mn-1 wt.%Nd magnesium alloy were investigated by advanced experimental and modeling techniques.Systematic quasi in-situ orientation mappings with a scanning electron microscope were performed to track the evolution of local and global microstructural characteristics as a function of annealing time.Solute segregation at targeted grain boundaries was measured using three-dimensional atom probe tomography.Level-set computer simulations were carried with different setups of driving forces to explore their contribution to the microstructure development with and without solute drag.The results showed that the favorable growth advantage for some grains leading to a transient stage of abnormal grain growth is controlled by several drivers with varying importance at different stages of annealing.For longer annealing times,residual dislocation density gradients between large and smaller grains are no longer important,which leads to microstructure stability due to predominant solute drag.Local fluctuations in residual dislocation energy and solute concentration near grain boundaries cause different boundary segments to migrate at different rates,which affects the average growth rate of large grains and their evolved shape.

Green Approach for <i>In-Situ</i>Growth of CdS Nanorods in Low Band Gap Polymer Network for Hybrid Solar Cell Applications

In-situ growth of CdS nanorods (NRs) has been demonstrated via solvothermal, in a low band gap polymer, poly [[4,8-bis[(2-ethylhexyl)oxy] benzo [1,2-b:4,5-b’] dithiophene-2,6-diyl] [3-fluoro-2-[(2-ethylhexyl) carbonyl] thieno [3,4-b] thiophenediyl]] (PTB7). It is a high yielding, green approach as it removes use of volatile and hazardous chemicals such as pyridine as ligand which are conventionally used to synthesize precursors of CdS (NRs). Moreover the solvothermal process is a zero emission process being a close vessel synthesis and hence no material leaching into the atmosphere during the synthesis. The PTB7:CdS nanocomposite has been characterized by SEM, XRD, FTIR, UV-visible spectroscopy techniques. The photoluminescence (PL) spectroscopy study of PTB7 with CdS NRs has shown significant PL quenching by the incorporation of CdS NRs in PTB7;this shows that CdS NRs are efficient electron acceptors with the PTB7. The PTB7:CdS is used as active layer in the fabrication of hybrid solar cells (HSC) as donor-acceptor combination in the bulk heterojunction (BHJ) geometry. The HSCs fabricated using this active layer without any additional supporting fullerene based electron acceptor has given power conversion efficiency of above 1%.