Thermal-stability of the enhanced piezoelectric,energy storage and electrocaloric properties of a lead-free BCZT ceramic

The lead-free Ba_0.85Ca_0.15Zr_0.10Ti_0.90O₃ (BCZT) relaxor ferroelectric ceramic has aroused much attention due to its enhanced piezoelectric, energy storage and electrocaloric properties. In this study, the BCZT ceramic was elaborated by the solid-state reaction route, and the temperature-dependence of the structural, electrical, piezoelectric, energy storage and electrocaloric properties was investigated. X-ray diffraction analysis revealed a pure perovskite phase, and the temperature-dependence of Raman spectroscopy, dielectric and ferroelectric measurements revealed the phase transitions in the BCZT ceramic. At room temperature, the strain and the large-signal piezoelectric coefficient reached a maximum of 0.062% and 234 pm V⁻¹, respectively. Furthermore, enhanced recovered energy density (W_rec = 62 mJ cm⁻³) and high-energy storage efficiency (η) of 72.9% at 130 °C were found. The BCZT ceramic demonstrated excellent thermal stability of the energy storage variation (ESV), less than ±5.5% in the temperature range of 30–100 °C compared to other lead-free ceramics. The electrocaloric response in the BCZT ceramic was explored via the indirect approach by using the Maxwell relation. Significant electrocaloric temperature change (ΔT) of 0.57 K over a broad temperature span (T_span = 70 °C) and enhanced coefficient of performance (COP = 11) were obtained under 25 kV cm⁻¹. The obtained results make the BCZT ceramic a suitable eco-friendly material for energy storage and solid-state electrocaloric cooling devices.

High-thermal stability of the recovered energy density and significant electrocaloric temperature change over a broad temperature span in a lead-free BCZT ceramic.     

Improvements in piezoelectric and energy harvesting properties with a slight change in depolarization temperature in modified BNKT ceramics by a simple technique

For many BNT-based ceramics, an attempt to increase the piezoelectric properties usually results in a decrease in depolarization temperature (T_d). This trend limits the applications of the materials. Many previous experiments have used different methods to enhance the piezoelectric properties and improve the T_d characteristic. In this study, we demonstrated a simple technique (thermal annealing) to enhance the piezoelectric properties with a very slight decrease in T_d by ∼2 °C for a modified BNKT ceramic (BNKT doped with ZnO). Other phase transition characteristic temperatures of the studied ceramics were also slightly changed. The optimum dielectric (ε_r = 651, tan δ = 0.0503, T_F–R = 167.38 °C, T_m = 305.41 °C, ε_max = 5551, T_B = 367.15 °C, T_d = 155.98 °C, and γ = 1.43), ferroelectric (P_max = 41.28 μC cm⁻², P_r = 35.85 μC cm⁻², E_c = 42.60 kV cm⁻¹ and R_sq = 1.42), piezoelectric (d₃₃ = 198 pC N⁻¹, k_p = 0.598, and g₃₃ = 34.35 × 10⁻³ Vm N⁻¹), and energy harvesting (FoM = 6.80 pm² N⁻¹) were obtained for the 8 h annealed ceramic. Furthermore, higher energy harvesting properties (which were 32% higher than that of the unannealed ceramic) were obtained after employing this technique.

In this study, we demonstrated a simple technique (thermal annealing) to enhance the piezoelectricity with a very slight decrease in T_d by ∼2 °C for a modified BNKT ceramic (BNKT doped with ZnO).     

Influence of Al2O3 nanoparticle doping on depolarization temperature,and electrical and energy harvesting properties of lead-free 0.94(Bi0.5Na0.5)TiO3–0.06BaTiO3 ceramics

In this research article, the effects of Al₂O₃ nanoparticles (0–1.0 mol%) on the phase formation, microstructure, dielectric, ferroelectric, piezoelectric, electric field-induced strain and energy harvesting properties of the 0.94(Bi_0.5Na_0.5)TiO₃–0.06BaTiO₃ (BNT–6BT) ceramic were investigated. All ceramics have been synthesized by a conventional mixed oxide method. The XRD and Raman spectra showed coexisting rhombohedral and tetragonal phases throughout the entire compositional range. An increase of the grain size, T_F–R, T_m, ε_max and δ_A values was noticeable when Al₂O₃ was added. Depolarization temperature (T_d), which was determined by the thermally stimulated depolarization current (TSDC), tended to increase with Al₂O₃ content. The good ferroelectric properties (P_r = 32.64 μC cm⁻², E_c = 30.59 kV cm⁻¹) and large low-field d₃₃ (205 pC N⁻¹) values were observed for the 0.1 mol% Al₂O₃ ceramic. The small Al₂O₃ additive improved the electric field-induced strain (S_max and ). The 1.0 mol% Al₂O₃ ceramic had a large piezoelectric voltage coefficient (g₃₃ = 32.6 × 10⁻³ Vm N⁻¹) and good dielectric properties (ε_r,max = 6542, T_d = 93 °C, T_F–R = 108 °C, T_m = 324 °C and δ_A = 164 K). The highest off-resonance figure of merit (FoM) for energy harvesting of 6.36 pm² N⁻¹ was also observed for the 1.0 mol% Al₂O₃ ceramic, which is suggesting that this ceramic has potential to be one of the promising lead-free piezoelectric candidates for further use in energy harvesting applications.

In this research article, the effects of Al₂O₃ nanoparticles (0–1.0 mol%) on the phase, microstructure, dielectric, ferroelectric, piezoelectric, electric field-induced strain and energy harvesting of the BNT–6BT ceramic were investigated.     

Multifunctional Nd3+ substituted Na0.5Bi0.5TiO3 as lead-free ceramics with enhanced luminescence,ferroelectric and energy harvesting properties

Herein, we present comprehensive investigations of the optical and electrical properties of Nd³⁺ substitution in sodium bismuth titanate ceramics (NBNT) with varying Nd³⁺ concentration. The room temperature photoluminescence (PL) emission for both unpoled and poled samples is observed to be a maximum for an Nd³⁺ substitution of 1 mol%. Upon poling, the PL intensity is observed to be quenched, consistent with the obtained XRD data, indicating an electric-field induced structural ordering towards higher symmetry, confirmed with the help of structural refinement. The evaluated ferroelectric to relaxor and antiferroelectric relaxor T_(F–R) was observed clearly from the poled dielectric–loss curve for the 1 mol% of Nd³⁺ substitution. Furthermore, the optimized NBNT exhibited a lower E_c and a higher off-resonance figure of merit (FOM_off) for energy harvesting by 12% and 30%, respectively, in comparison with un-doped NBT.

Herein, we present investigations on the effect of electrical poling on the optical and electrical properties of Nd³⁺ substituted NBT ceramics with varying Nd³⁺ concentrations.     

High electrostrictive properties and energy storage performances with excellent thermal stability in Nb-doped Bi0.5Na0.5TiO3-based ceramics

As a promising candidate material replacing Pb(ZrTi)O₃ (PZT), the lead-free Bi_0.5Na_0.5TiO₃ (BNT) system exhibits outstanding piezoelectric and ferroelectric properties. However, the weak thermal stability of these electric properties hampers its practical applications. In this work, we designed and prepared novel Nb-doped 0.76Bi_0.5Na_0.5TiO₃–0.24Bi_0.5K_0.5TiO₃ (BNT–BKT) ceramics with superior temperature stability of electric properties. Both strain as well as discharging properties of 5% Nb-doped BNT–BKT ceramics varied less than 3% and 12.5% respectively from room temperature to 160 °C, ascribed to the enlarged gap between the depolarized temperature (T_d or T_F–R) and the maximum dielectric temperature (T_m). In addition, we investigated the impacts of Nb doping on the phase transition, dielectric, piezoelectric and ferroelectric behaviors of BNT–BKT ceramics in detail. Temperature dependent dielectric spectrums indicated that T_d decreased below room temperature with Nb modifying, revealing that the phase structure transformed from ferroelectric into ergodic relaxor. Accordingly, the maximum strain value of 0.21% and recoverable energy storage of 1.2 J cm⁻³ were simultaneously acquired at the critical composition of 5% Nb incorporation. Our results provide an effective means of obtaining BNT-based ceramics with simultaneously thermally stable strain and discharge properties for wide temperature actuator and capacitor applications.

Lowering T_d to enlarge the temperature range between T_d and the maximum dielectric temperature (T_m) proved to be an effective strategy to enhance the thermal stability strain and energy storage properties in BNT-based ceramics.     

Structure,dielectric, and piezoelectric properties of K0.5Na0.5NbO3-based lead-free ceramics

Lead-free ceramics based on the (1 − x)K_0.5Na_0.5NbO₃–xBi(Zn_0.5Ti_0.5)O₃ (KNN–BZT) system obtained via the conventional solid-state processing technique were characterized for their crystal structure, microstructure, and electrical properties. Rietveld analysis of X-ray diffraction data confirmed the formation of a stable perovskite phase for Bi(Zn_0.5Ti_0.5)O₃ substitutions up to 30 mol%. The crystal structure was found to transform from orthorhombic Amm2 to cubic Pm$\bar{3}$m through mixed rhombohedral and tetragonal phases with the increase in Bi(Zn_0.5Ti_0.5)O₃ content. Temperature-dependent dielectric behavior indicated an increase in diffuseness of both orthorhombic to tetragonal and tetragonal to cubic phase transitions as well as a gradual shift towards room temperature. The sample with x ≈ 0.02 exhibited a mixed rhombohedral and orthorhombic phase at room temperature. A high-temperature X-ray diffraction study confirmed the strong temperature dependence of the phase coexistence. The sample with the composition 0.98(K_0.5Na_0.5NbO₃)–0.02(BiZn_0.5Ti_0.5O₃) showed an improved room temperature piezoelectric coefficient d₃₃ = 109 pC/N and a high Curie temperature T_C = 383 °C.

Room temperature powder X-ray diffraction patterns of (1 – x)K_0.5Na_0.5NbO₃–xBi(Zn_0.5Ti_0.5)O₃ system.     

Thermally-stable high energy storage performances and large electrocaloric effect over a broad temperature span in lead-free BCZT ceramic

Ba_0.85Ca_0.15Zr_0.10Ti_0.90O₃ (BCZT) relaxor ferroelectric ceramics exhibit enhanced energy storage and electrocaloric performances due to their excellent dielectric and ferroelectric properties. In this study, the temperature-dependence of the structural and dielectric properties, as well as the field and temperature-dependence of the energy storage and the electrocaloric properties in BCZT ceramics elaborated at low-temperature hydrothermal processing are investigated. X-ray diffraction and Raman spectroscopy results confirmed the ferroelectric–paraelectric phase transition in the BCZT ceramic. At room temperature and 1 kHz, the dielectric constant and dielectric loss reached 5000 and 0.029, respectively. The BCZT ceramic showed a large recovered energy density (W_rec) of 414.1 mJ cm⁻³ at 380 K, with an energy efficiency of 78.6%, and high thermal-stability of W_rec of 3.9% in the temperature range of 340–400 K. The electrocaloric effect in BCZT was explored via an indirect approach following the Maxwell relation at 60 kV cm⁻¹. The significant electrocaloric temperature change of 1.479 K at 367 K, a broad temperature span of 87 K, an enhanced refrigerant capacity of 140.33 J kg⁻¹, and a high coefficient of performance of 6.12 obtained at 60 kV cm⁻¹ make BCZT ceramics potentially useful coolant materials in the development of future eco-friendly solid-state refrigeration technology.

Thermally-stable recovered energy density and significant electrocaloric temperature change over a broad temperature span in BCZT ceramic elaborated by low-temperature hydrothermal processing.     

Tunable electronic and optical properties of a BAs/As heterostructure by vertical strain and external electric field

Based on the first-principles method, we investigated the electronic properties of a BAs/arsenene (As) van der Waals (vdW) heterostructure and found that it has an intrinsic type-II band alignment with a direct band gap of 0.25 eV, which favors the separation of photogenerated electrons and holes. The band gap can be effectively modulated by applying vertical strain and external electric field, displaying a large alteration in the band gap via the strain and experiencing an indirect-to-direct band gap transition. Moreover, the band gap of the heterostructure varies almost linearly with external electric field, and the semiconductor-to-metal transition can be realized in the presence of a strong electric field. The calculated band alignment and optical absorption reveal that the BAs/As heterostructure could present an excellent light-harvesting performance. The absorption strength can be tuned mainly by interlayer coupling, while external electric field shows clear regulating effects on the absorption strength and absorption edge.

The CBM (VBM) of the heterostructure is mainly contributed by the BAs (arsenene), which will favor the separation of photogenerated electron–hole pairs.     

Influence of molybdenum and technetium doping on visible light absorption,optical and electronic properties of lead-free perovskite CsSnBr3 for optoelectronic applications

Lead-free metal halide perovskites have nowadays become familiar owing to their potential use in solar cells and other optoelectronic applications. In this study, we carried out the structural, elastic, electronic, and optical properties of pure and metal (Mo/Tc) doped CsSnBr₃ by using the density functional theory. The metal doping CsSnBr₃ displays a narrowing band gap and as a result the optical functions exhibit high absorption and high conductivity in the visible region. Metal doping samples also reveal a high dielectric constant which indicates a low charge-carrier recombination rate and hence enhances the device performance. The optical absorption spectra of metal doped samples greatly shifted (red-shift) towards the lower energy region compared with the pure sample which creates a high-intensity peak in the visible region. The mechanical parameter reveals a highly ductile, soft, and flexible nature which indicates the suitability for use in thin films. The electronic band structure of metal-doped CsSnBr₃ shows an intermediate state that assists the excited electron to pass on from valence band to conduction band. The overall study suggests that lead-free CsSn_0.875Tc_0.125Br₃ perovskite is a promising candidate for solar cells and other optoelectronic applications.

In this study, the metal doping enhanced the optoelectronic properties of lead-free perovskite CsSnBr₃; hence CsSn_0.875Tc_0.125Br₃ is promising for solar cells and other optoelectronic applications.     

Improved electrical transport properties of polycrystalline La0.8(Ca0.12Sr0.08)MnO3 ceramics by Ag2O doping

Polycrystalline La_0.8(Ca_0.12Sr_0.08)MnO₃:mol%Ag_x (LCSMO:Ag_x, x = 0, 0.1, 0.2, 0.3 and 0.4) ceramics were synthesized by the sol–gel technique. Structural, electrical and magnetic properties of the LCSMO:Ag_x ceramics were investigated in detail. X-ray diffraction (XRD) data analyses revealed that all the samples were crystalized in the orthorhombic structure with space group of Pnma. With the increase in Ag doping (x), the grain sizes of the LCSMO:Ag_x samples increased and the amount of grain boundaries (GBs) decreased accordingly. At the same time, the Mn–O bond distance and the Mn–O–Mn bond angles changed correspondingly, leading to the slight increase in the lattice constants (a, b and c) and slight expansion of cell volume (V). For the LCSMO:Ag_x sample with x = 0.3, the optimal values of temperature coefficient of resistivity (TCR) and magnetoresistance (MR) reached 16.22% K⁻¹ (265.1 K) and 42.07% K⁻¹ (270.48 K), respectively. In addition, the fitting analysis of ρ–T curves showed that the experimental data were consistent with the theoretical calculation data. In the T < T_MI (metal-insulator transition temperature) region, the electrical conduction mechanism of LCSMO:Ag_x was clarified by electron-magnon, electron–electron and electron-phonon scattering. In the T > T_MI region, the resistivity data were interpreted by using the adiabatic small-polaron hopping model. Furthermore, in the entire temperature range, the phenomenological equation called the percolation model was used to explain the resistivity data and the phase-separation mechanism of ferromagnetic metallic (FM) and paramagnetic insulating (PI) phases. All the obtained results indicated that the improvement in the electrical properties of the LCSMO:Ag_x samples was attributed to the doping of Ag, which changed the A-site (La, Ca and Sr ions) average ion radius, the Mn–O–Mn bond angles and the Mn–O bond distance. In addition, the grain size increased, which led to improvement in the Mn⁴⁺ ion concentration and the GBs connectivity in the LCSMO:Ag_x polycrystalline ceramics.

Polycrystalline La_0.8(Ca_0.12Sr_0.08)MnO₃:mol%Ag_x (LCSMO:Ag_x, x = 0, 0.1, 0.2, 0.3 and 0.4) ceramics were synthesized by the sol–gel technique.     

Tuning MoSO monolayer properties for optoelectronic and spintronic applications: effect of external strain,vacancies and doping

Since the successful synthesis of the MoSSe monolayer, two-dimensional (2D) Janus materials have attracted huge attention from researchers. In this work, the MoSO monolayer with tunable electronic and magnetic properties is comprehensively investigated using first-principles calculations based on density functional theory (DFT). The pristine MoSO single layer is an indirect gap semiconductor with energy gap of 1.02(1.64) eV as predicted by the PBE(HSE06) functional. This gap feature can be efficiently modified by applying external strain presenting a decrease in its value upon switching the strain from compressive to tensile. In addition, the effects of vacancies and doping at Mo, S, and O sites on the electronic structure and magnetic properties are examined. Results reveal that Mo vacancies, and Al and Ga doping yield magnetic semiconductor 2D materials, where both spin states are semiconductors with significant spin-polarization at the vicinity of the Fermi level. In contrast, single S and O vacancies induce a considerable gap reduction of 52.89% and 58.78%, respectively. Doping the MoSO single layer with F and Cl at both S and O sites will form half-metallic 2D materials, whose band structures are generated by a metallic spin-up state and direct gap semiconductor spin-down state. Consequently, Mo_V, Mo_Al, Mo_Ga, S_F, S_Cl, O_F, and O_Cl are magnetic systems, and the magnetism is produced mainly by the Mo transition metal that exhibits either ferromagnetic or antiferromagnetic coupling. Our work may suggest the MoSO Janus monolayer as a prospective candidate for optoelectronic applications, as well as proposing an efficient approach to functionalize it to be employed in optoelectronic and spintronic devices.

Atomic structure and stability analysis of the MoSO Janus monolayer.     

跟骨X线照片对小儿废用性骨质疏松症的诊断评估价值

目的探讨跟骨X线照片对小儿废用性骨质疏松症的诊断评估价值。方法对22例卧床3月以上患儿分别在卧床前、卧床后1月、3月进行跟骨侧位X线照片和跟骨、胫骨上、下端、腰椎1－4DEXA检查。结果受检部位BMD和X线跟骨小梁Jhamaria分级随卧床时间延长而逐渐下降;跟骨Jhamaria分级越低;,各受检部位BMD亦越低;卧床3个月后,两种检查方法在跟骨的检出率有显著性差异;跟骨X线照片与跟骨BMD相关性最好。结论跟骨X线照片为适合我国的小儿废用性骨质疏松症的检查诊断。     

Effects of electric field and strain engineering on the electronic properties,band alignment and enhanced optical properties of ZnO/Janus ZrSSe heterostructures

The formation of van der Waals heterostructures (vdWHs) have recently emerged as promising structures to make a variety of novel nanoelectronic and optoelectronic devices. Here, in this work, we investigate the structural, electronic and optical features of ZnO/ZrSSe vdWHs for different stacking patterns of ZnO/SeZrS and ZnO/SZrSe by employing first-principles calculations. Binding energy and ab initio molecular dynamics calculations are also employed to confirm the structural and thermal stability of the ZnO/ZrSSe vdWHs for both models. We find that in both stacking models, the ZnO and ZrSSe layers are bonded via weak vdW forces, leading to easy exfoliation of the layers. More interestingly, both the ZnO/SeZrS and ZnO/SZrSe vdWHs posses type-II band alignment, making them promising candidates for the use of photovoltaic devices because the photogenerated electrons–holes are separated at the interface. The ZnO/ZrSSe vdWHs for both models possess high performance absorption in the visible and near-infrared regions, revealing their use for acquiring efficient photocatalysts. Moreover, the band gap values and band alignments of the ZnO/ZrSSe for both models can be adjusted by an electric field as well as vertical strains. There is a transformation from semiconductor to metal under a negative electric field and tensile vertical strain. These findings demonstrate that ZnO/ZrSSe vdWHs are a promising option for optoelectronic and nanoelectronic applications.

Here, in this work, we investigate the structural, electronic and optical features of ZnO/ZrSSe vdWHs for different stacking patterns of ZnO/SeZrS and ZnO/SZrSe by employing first-principles calculations.     

The effect of diameter size of single-walled carbon nanotubes on their high-temperature energy storage behaviour in ionic liquid-based electric double-layer capacitors

We investigated the effect of the diameter size of single-walled carbon nanotubes (SWCNTs), on their high-temperature energy storage behavior in an electric double layer capacitor (EDLC) using the ionic liquid triethyl(2-methoxyethyl) phosphonium bis(trifluoromethylsulfonyl)imide (P_222(2O1)-TFSI). We used four SWCNT samples with diameter sizes ranging from 0.8 to 5 nm, and evaluated their electrochemical charge storage behavior through galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS). We found that for the SWCNTs with small average diameter of 1 nm, the value of the electrode capacitance measured at a current density of 5 mA g⁻¹ increased from 15.8 at room temperature to 27.5 F g⁻¹ at 150 °C, and the value measured at a current density of 80 mA g⁻¹ increased from 14.0 at room temperature to 22.1 F g⁻¹ at 150 °C. The larger diameter samples on the other hand did not show any significant change in their capacitance with temperature. We calculated the size of the interstitial tube spaces from the Raman spectra of the samples, and used density functional theory (DFT) calculations to estimate the sizes of the cation and anion of the electrolyte. The obtained results suggest that the temperature-induced changes in the electrolyte properties improved the ion accessibility into the otherwise constrained space inside the small diameter SWCNTs, while the spaces inside the larger SWCNTs already provided easily accessible storage sites hence good performance at room temperature, making the increase in temperature of little to no effect on the charge storage performance in such SWCNTs.

Temperature-induced changes in electrolyte improved ion accessibility inside small SWCNTs, while spaces inside larger SWCNTs provided accessible storage sites and good performance at RT, rendering temperature of little effect on their charge storage performance.     

Post-synthetically modified metal–porphyrin framework GaTCPP for carbon dioxide adsorption and energy storage in Li–S batteries

Lithium–sulphur batteries attract increasing interest due to their high theoretical specific capacity, advantageous economy, and “eco-friendliness”. In this study, a metal–organic framework (MOF) GaTCPP containing a porphyrinic base ligand was used as a conductive additive for sulphur. GaTCPP was synthesized, characterized, and post-synthetically modified by the transition metal ions (Co²⁺/Ni²⁺). The doping of GaTCPP ensured an increase in the carbon dioxide adsorption capacities, which were measured under different conditions. Post-synthetic modification of GaTCPP with Co²⁺/Ni²⁺ ions has been shown to increase carbon dioxide storage capacity from 22.8 wt% for unmodified material to 23.1 wt% and 26.5 wt% at 0 °C and 1 bar for Co²⁺ and Ni²⁺-doped analogues, respectively. As a conductive part of cathode material, MOFs displayed successful sulphur capture and encapsulation proven by stable charge/discharge cycle performances, high-capacity retention, and coulombic efficiency. The electrodes with pristine GaTCPP showed a discharge capacity of 699 mA h g⁻¹ at 0.2C in the fiftieth cycle. However, the doping of GaTCPP by Ni²⁺ has a positive impact on the electrochemical properties, the capacity increased to 778 mA h g⁻¹ in the fiftieth cycle at 0.2C.

Metal–porphyrin framework GaTCPP was used for carbon dioxide adsorption and as a host for preparation of a Li–S battery cathode material.     

Modulating the magnetic properties of MoS2 monolayers by group VIII doping and vacancy engineering

In this work, density functional theory is adopted to study the electronic and magnetic properties of MoS₂ monolayers combined with a single S vacancy defect and a group VIII (G8) atom dopant, in which the dopant is incorporated via Mo substitution. The calculated results show that the magnetic properties of monolayer MoS₂ can be tuned by changing the distribution of the G8 atom and S vacancy. The S vacancy tends to decrease the net magnetic moment of the doped system when these two defects are in their closest configuration. By adjusting the distance between the dopant and the S vacancy, the doped MoS₂ monolayer may show a variable net magnetic moment. In particular, all of the Ni-doped MoS₂ monolayers show zero magnetic moment with or without an S vacancy. The mean-field approximation is used to estimate the Curie temperature (T_C). Our results show that Fe, Co, Ru, Rh, Os and Ir-doped MoS₂ monolayers are potential candidates for ferromagnetism above room temperature. The density of states calculations provide further explanations as to the magnetic behavior of these doped systems. These results provide a new route for the potential application of atomically thin dilute magnetic semiconductors in spintronic devices by employing monolayer MoS₂.

In this work, the density functional theory study shows that the magnetic properties of MoS₂ monolayer can be tuned by the distribution of group VIII atom and S vacancy, in which the dopant is incorporated via Mo subsitution.     

轻度修饰低密度脂蛋白诱导内皮细胞基因差异的表达

背景：研究表明，轻度修饰低密度脂蛋白与动态粥样硬化的形成有关，除了具有蓄积低密度脂蛋白作用外还有很强的生物学活性，可在培养细胞及动物体内诱导巨噬细胞集落刺激因子等多种生物活性物质的表达。 目的：采用差异显示-聚合酶链反应技术研究轻度修饰低密度脂蛋白诱导血管内皮细胞的基因表达差异，为进一步阐明轻度修饰低密度脂蛋白与动脉粥样硬化的关系奠定基础。 设计：重复测量设计。 单位：泰山医学院。 材料：实验于2003-07/2004-07在泰山医学院基础研究所完成。人及早静脉内皮细胞培养基为M199，在37℃，50ml/L的CO2条件下培养。细胞生长到融合状态时，培养基中加入轻度修饰低密度脂蛋白，至终浓度为400mg/L，诱导处理30h。 方法：用差异显示反转录-聚合酶链反应技术分析轻度修饰低密度脂蛋白诱导下人血管内皮细胞的基因表达差异，并用反向Northern分析证实差异显示基因片段。 主要观察指标：（1）内皮细胞mRNA的差异显示分析。（2）差异片段的克隆，序列分析及同源性比较。（3）诱导与非诱导小鼠肝脏mRNA的反向Northern分析。 结果：轻度修饰低密度脂蛋白诱导下人血管内皮细胞出现一些上调和下调的基因片段。上调基因有胸腺素β4,FGFRI原癌基因伴随蛋白，FK506结合蛋白，rTSβ蛋白和细胞间粘附分子1；下调的基因有Apo bec-1结合蛋白1，细胞色素B561和ERP72。 结论：用差异显示反转录-聚合酶链反应方法证实在体外轻度修饰低密度脂蛋白可旋夫及早静脉内皮细胞一些基因的表达水平变化，引起轻度修饰低密度脂蛋白血管内皮细胞发生病理变化，最终导致动脉粥样硬化斑块的形成。     

轻度修饰低密度脂蛋白诱导内皮细胞基因差异的表达

背景研究表明,轻度修饰低密度脂蛋白与动脉粥样硬化的形成有关,除了具有蓄积低密度脂蛋白作用外还有很强的生物学活性,可在培养细胞及动物体内诱导巨噬细胞集落刺激因子等多种生物活性物质的表达.目的采用差异显示-聚合酶链反应技术研究轻度修饰低密度脂蛋白诱导血管内皮细胞的基因表达差异,为进一步阐明轻度修饰低密度脂蛋白与动脉粥样硬化的关系奠定基础.设计重复测量设计.单位泰山医学院.材料实验于2003-07/2004-07在泰山医学院基础研究所完成.人脐静脉内皮细胞培养基为M199,在37℃,50 mL/L的CO2条件下培养.细胞生长到融合状态时,培养基中加入轻度修饰低密度脂蛋白,至终浓度为400mg/L,诱导处理30 h.方法用差异显示反转录-聚合酶链反应技术分析轻度修饰低密度脂蛋白诱导下人血管内皮细胞的基因表达差异,并用反向Northern分析证实差异显示基因片段.主要观察指标①内皮细胞mRNA的差异显示分析.②差异片段的克隆、序列分析及同源性比较.③诱导与非诱导小鼠肝脏mRNA的反向Northern分析.结果轻度修饰低密度脂蛋白诱导下人血管内皮细胞出现一些上调和下调的基因片段.上调基因有胸腺素β4、FGFRI原癌基因伴随蛋白、FK506结合蛋白、rTSβ蛋白和细胞间粘附分子1;下调的基因有Apobec-1结合蛋白1、细胞色素B561和ERP72.结论用差异显示反转录-聚合酶链反应方法证实在体外轻度修饰低密度脂蛋白可诱导人脐静脉内皮细胞一些基因的表达水平变化,引起轻度修饰低密度脂蛋白血管内皮细胞发生病理变化,最终导致动脉粥样硬化斑块的形成.     

Electronic and optical properties of Janus ZrSSe by density functional theory

In the present work, we investigate systematically the electronic and optical properties of Janus ZrSSe using first-principles calculations. Our calculations demonstrate that the Janus ZrSSe monolayer is an indirect semiconductor at equilibrium. The band gap of the Janus ZrSSe is 1.341 eV using the Heyd–Scuseria–Ernzerhof hybrid functional, larger than the band gap of ZrSe₂ monolayer and smaller than that of ZrS₂ monolayer. Based on the analysis of the band edge alignment, we confirm that the Janus ZrSSe monolayer possesses photocatalytic activities that can be used in water splitting applications. While strain engineering plays an important role in modulating the electronic properties and optical characteristics of the Janus ZrSSe monolayer, the influence of the external electric field on these properties is negligible. The biaxial strain, ε_b, has significantly changed the band of the Janus ZrSSe monolayer, and particularly, the semiconductor–metal phase transition which occurred at ε_b = 7%. The Janus ZrSSe monolayer can absorb light in both visible and ultraviolet regions. Also, the biaxial strain has shifted the first optical gap of the Janus ZrSSe monolayer. Our findings provide additional information for the prospect of applying the Janus ZrSSe monolayer in nanoelectronic devices, especially in water splitting technology.

In the present work, we investigate systematically the electronic and optical properties of Janus ZrSSe using first-principles calculations.