Artificial Domain Patterning in Ultrathin Ferroelectric Films via Modifying the Surface Electrostatic Boundary Conditions.

Nanoscale spatially controlled modulation of the properties of ferroelectrics via artificial domain pattering is crucial to their emerging optoelectronics applications. New patterning strategies to achieve high precision and efficiency and to link the resultant domain structures with device functionalities are being sought. Here, we present an epitaxial heterostructure of SrRuO3/PbTiO3/SrRuO3, wherein the domain configuration is delicately determined by the charge screening conditions in the SrRuO3 layer and the substrate strains. Chemical etching of the top SrRuO3 layer leads to a transition from in-plane a domains to out-of-plane c domains, accompanied by a giant (>105) modification in the second harmonic generation response. The modulation effect, coupled with the plasmonic resonance effect from SrRuO3, enables a highly flexible design of nonlinear optical devices, as demonstrated by a simulated split-ring resonator metasurface. This domain patterning strategy may be extended to more thin-film ferroelectric systems with domain stabilities amenable to electrostatic boundary conditions.

S100A8/A9, an Upregulated Host Factor in BK Virus Infection after Kidney Transplantation, Is Associated with Allograft Function Impairment.

BK virus (BKV) is one of the most common pathogens in post-transplantation infections. For kidney transplantation, BKV infection results in the impairment of allograft function and thus increases the risk of allograft loss. However, clinical evaluation of the prognosis of BKV-associated allograft impairment is difficult. In the present study, differential plasma proteins were screened using proteomic methods from ten patients with a transition from BKV-negative to BKV activation. We identified 12 differentially expressed proteins, and S100A8 and S100A9 were the top two upregulated proteins. Data from a cross-sectional study with 66 BKV-negative and 66 BKV-positive recipients of renal transplantation indicated that plasma S100A8/A9 was upregulated in BKV-infected recipients. Plasma S100A8/A9 positively correlated with the 1 month creatinine increase (ρ = 0.499, P = 0.021) and negatively correlated with the 1 month estimated glomerular filtration rate change (ρ = -0.618, P = 0.003) in recipients with BK viremia. Using least absolute shrinkage and selection operator regression models, we found that S100A8/A9 was an independent risk factor for the decrease in allograft function after BKV infection. In conclusion, S100A8/A9 is a potential host biomarker for the clinical evaluation of BKV-associated allograft function impairment in kidney transplantation.

Theoretical and Experimental Study of 3-Pentanol Autoignition: Ab Initio Calculation, Shock Tube Experiments, and Kinetic Modeling.

3-Pentanol is a potential alternative fuel or a green fuel additive for modern engines. The H-abstraction reactions from 3-pentanol by H, CH3, HO2, and OH radicals are significant in the 3-pentanol oxidation process. However, corresponding rate constants are forced to rely on either analogy from sec-butanol or estimation from alkanes due to a lack of direct experimental and theoretical study. In this work, stationary points on the potential energy surfaces (PESs) were calculated with the high-level DLPNO-CCSD(T)/CBS(T-Q)//M06-2X/cc-pVTZ method, which is further used to benchmark against the CBS-QB3 method. Then, the high-pressure limit rate constants for target reactions, over a broad range of temperature (400-2000 K), were calculated with the phase-space theory and conventional transition state theory. A comparison was made between the calculated rate constants and the values available in Carbonnier et al. [ Proc. Combust. Inst. 2019, 37(1), 477-484]. The rate constants for the above H-abstraction reactions in the Carbonnier model were updated with the calculated results, followed by a modification based on the computed results of 3-pentanol + HO2 to obtain the revised model. Validation against the shock tube (ST) and the jet-stirred reactor (JSR) measurements from the literature proved the revised model an optimal one. Furthermore, using an ST, ignition delay times (IDTs) for the 3-pentanol/air mixtures were measured spanning a temperature range of 920-1450 K, pressures of 6, 10, and 20 bar, and equivalence ratios of 0.5, 1.0, and 1.5. Generally, IDTs decrease with increasing temperature and reflected shock pressure. Improved predictions to present experimental data were obtained by using the revised model as compared with the Carbonnier model. Finally, sensitivity analysis was conducted using the revised model to gain an in-depth comprehension of the 3-pentanol autoignition.

Giant electric field-induced second harmonic generation in polar skyrmions.

Electric field-induced second harmonic generation allows electrically controlling nonlinear light-matter interactions crucial for emerging integrated photonics applications. Despite its wide presence in materials, the figures-of-merit of electric field-induced second harmonic generation are yet to be elevated to enable novel device functionalities. Here, we show that the polar skyrmions, a topological phase spontaneously formed in PbTiO3/SrTiO3 ferroelectric superlattices, exhibit a high comprehensive electric field-induced second harmonic generation performance. The second-order nonlinear susceptibility and modulation depth, measured under non-resonant 800 nm excitation, reach ~54.2 pm V-1 and ~664% V-1, respectively, and high response bandwidth (higher than 10 MHz), wide operating temperature range (up to ~400 K) and good fatigue resistance (>1010 cycles) are also demonstrated. Through combined in-situ experiments and phase-field simulations, we establish the microscopic links between the exotic polarization configuration and field-induced transition paths of the skyrmions and their electric field-induced second harmonic generation response. Our study not only presents a highly competitive thin-film material ready for constructing on-chip devices, but opens up new avenues of utilizing topological polar structures in the fields of photonics and optoelectronics.

Birc3 and Tip1 are upregulated in renal ischemia reperfusion injury.

Identification of ischemia-reperfusion injury (I/R)-associated genes is essential for exploring I/R novel mechanisms. Previously, we screened differentially expressed genes in renal I/R mouse models and found that Tax1 binding protein 3 (Tip1) and baculoviral IAP repeat containing 3 (Birc3) are two upregulated genes in I/R. In the present study, we analyzed the expression of Tip1 and Birc3 in I/R models. We found that the expression of Tip1 and Birc3 was upregulated in I/R-treated mice, whereas Tip1 was downregulated and Birc3 was upregulated in oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro models. By inhibiting Birc3 with AT-406 in I/R-treated mice, we observed that the serum creatinine or blood urea nitrogen did not vary. However, inhibition of Birc3 enhanced apoptosis of kidney tissues induced by I/R treatment. Consistently, we found that inhibition of Birc3 also increased the apoptosis rate in tubular epithelial cells induced by OGD/R. These data demonstrated that Tip1 and Birc3 were upregulated in I/R injury. The upregulation of Birc3 may protect against renal I/R injury.

CLCF1 is up-regulated in renal ischemia reperfusion injury and may associate with FOXO3.

Background: Ischemia-reperfusion injury (IRI) is one of the most important risk factors for acute kidney injury. In kidney transplantation, renal IRI can induce delayed graft function (DGF). However, the mechanisms that link IRI to DGF remain unclear. This study aimed to find molecular markers of renal IRI which are also associated with DGF. Methods: A previously constructed database of differentially expressed genes in a murine IRI model was compared with a published DGF database. The expression of cardiotrophin-like cytokine factor 1 (CLCF1) was detected using immunohistochemistry (IHC) and real-time quantitative polymerase chain reaction (qPCR) assays. Serum CLCF1 was measured using an enzyme-linked immunosorbent assay (ELISA), and serum creatinine (Cr) was tested to evaluate kidney function. Results: By comparing the IRI database and the DGF database, we identified 107 differentially expressed genes, including 79 upregulated and 28 downregulated genes. CLCF1 was one of the upregulated genes found in the 2 databases. The levels of CLCF1 in IRI-treated kidney tissues and serum CLCF1 were upregulated compared to sham-operated mice. CLCF1 belongs to the interleukin-6 (IL-6) family, and the forkhead box O3 (FOXO3) gene plays a key role in regulating IL-6 expression. We observed that FOXO3 knockout induced an increase in serum CLCF1 levels in sham-operated mice. However, FOXO3 knockout failed to increase CLCF1 levels in IRI-treated mice. Conclusions: CLCF1 is upregulated in renal IRI and may be regulated by FOXO3. Our data indicated that CLCF1 might be a potential biomarker linking renal IRI to DGF in kidney transplantation.

High Energy Performance Ferroelectric (Ba,Sr)(Zr,Ti)O3 Film Capacitors Integrated on Si at 400 °C.

BaTiO3-based ferroelectrics have been extensively studied due to their large dielectric constants and a high saturated polarization, which have the potential to store or supply electricity of very high energy and power densities. In order to further improve the energy efficiency η and the recyclable energy density Wrec, an A, B-site co-doped (Ba0.95,Sr0.05)(Zr0.2,Ti0.8)O3 ceramic target was used for sputter deposition of film capacitor structures on Si. This film composition reduces the remnant polarization Pr, while the choice of a low-temperature, templated sputtering process facilitates the formation of high-density arrays of columnar nanograins (average diameter d ∼20 nm) and grain boundary dead layers. This self-assembled nanostructure further delays the saturation of the electric polarization, leading to a high energy density Wrec of ∼148 J/cm3 and a high energy efficiency η of ∼90%. Moreover, the (Ba0.95,Sr0.05)(Zr0.2,Ti0.8)O3 film capacitors retain their high energy storage performance in a broad range of working temperature (-175-300 °C) and operating frequency (1 Hz-20 kHz). They are also fatigue-free after up to 2 × 109 switching cycles. Our work provides a new method and a cost-effective processing route for the creation and integration of high-performance dielectric capacitors for energy storage applications.

Ufmylation Is Activated in Renal Cancer and Is Not Associated with von Hippel-Lindau Mutation.

Clear cell renal cell carcinoma is the most common in all of the renal cancers; however, it lacks ideal molecular target for treatment. In the present study, we identified that ufmylation, a novel ubiquitin-like modification, was significantly upregulated in renal cancer tissues. Ufmylation is known to be closely associated with endoplasmic reticulum (ER) stress and protein quality control. To explore the relation between ufmylation and protein degradation pathways in renal cancer cells, we pharmacologically altered the ubiquitin-proteasome (UPS) and autophagy pathways. We found that the ufmylation levels were not varied by autophagy activation or inhibition. Consistently, the LC3 conversion, as an important biomarker of autophagy, was comparable between renal caner tissues and para-cancer tissues, indicating that the increase of ufmylation in renal cancer may be not related with autophagy. In contrast, blocking UPS with MG132 activated ufmylation in renal cancer cells, suggesting that the activation of ufmylation in renal cancer may be associated with the UPS activity. However, the ufmylation levels were not associated with mutations of the von Hippel-Lindau (VHL) gene, a specific E3 ligase of the UPS and has high mutation rate in renal cancer. Besides, we found that sunitinib, a multi-targeted tyrosine kinase inhibitor, could significantly inhibit ufmylation, whereas overexpression of active Ufm1 partially inhibited the antitumor effects of sunitinib. These results highlight that ufmylation might be a novel molecular candidate for renal cancer.