Large Nonlinear Transverse Conductivity and Berry Curvature in KTaO3 Based Two-Dimensional Electron Gas.

Two-dimensional electron gas (2DEG) at oxide interfaces exhibits various exotic properties stemming from interfacial inversion and symmetry breaking. In this work, we report large nonlinear transverse conductivities in the LaAlO3/KTaO3 interface 2DEG under zero magnetic field. Skew scattering was identified as the dominant origin based on the cubic scaling of nonlinear transverse conductivity with linear longitudinal conductivity and 3-fold symmetry. Moreover, gate-tunable nonlinear transport with pronounced peak and dip was observed and reproduced by our theoretical calculation. These results indicate the presence of Berry curvature hotspots and thus a large Berry curvature triplet at the oxide interface. Our theoretical calculations confirm the existence of large Berry curvatures from the avoided crossing of multiple 5d-orbit bands, orders of magnitude larger than that in transition-metal dichalcogenides. Nonlinear transport offers a new pathway to probe the Berry curvature at oxide interfaces and facilitates new applications in oxide nonlinear electronics.

Direct experimental evidence of physical origin of electronic phase separation in manganites.

Electronic phase separation in complex oxides is the inhomogeneous spatial distribution of electronic phases, involving length scales much larger than those of structural defects or nonuniform distribution of chemical dopants. While experimental efforts focused on phase separation and established its correlation with nonlinear responses under external stimuli, it remains controversial whether phase separation requires quenched disorder for its realization. Early theory predicted that if perfectly "clean" samples could be grown, both phase separation and nonlinearities would be replaced by a bicritical-like phase diagram. Here, using a layer-by-layer superlattice growth technique we fabricate a fully chemically ordered "tricolor" manganite superlattice, and compare its properties with those of isovalent alloyed manganite films. Remarkably, the fully ordered manganite does not exhibit phase separation, while its presence is pronounced in the alloy. This suggests that chemical-doping-induced disorder is crucial to stabilize the potentially useful nonlinear responses of manganites, as theory predicted.

Ethanol-Induced Hydrogen Insertion in Ultrafine IrPdH Boosts pH-Universal Hydrogen Evolution.

Engineering Pt-free catalysts for hydrogen evolution reaction (HER) with high activity and stability is of great significance in electrochemical hydrogen production. Herein, in situ chemical H intercalation into ultrafine Pd to activate this otherwise HER-inferior material to form the ultrafine IrPdH hydride as an efficient and stable HER electrocatalyst is proposed. The formation of PdIrH depends on a new hydrogenation strategy via using ethanol as the hydrogen resource. It is demonstrated that H atoms in IrPdH originate from the OH and CH2  of ethanol, which fills the gap of ethanol as the hydrogen source for the preparation of Pd hydride. Thanks to the incorporation of H/Ir atoms and ultrafine structure, the IrPdH exhibits superior HER activity and stability in the whole pH range. The IrPdH delivers very low overpotentials of 14, 25 and 60 mV at a current density of 10 mA cm-2 respectively in 0.5 m H2 SO4 , 1 m KOH, and 1 m PBS electrolytes, which are much better than those of commercial Pt/C and most reported noble metal electrocatalysts. Theoretical calculations confirm that interstitial hydrogen availably refines the electronic density of Pd and Ir sites, which optimizes the adsorption of *H and leads to the significant enhancement of HER performance.

Fertility intentions among young people in the era of China's three-child policy: a national survey of university students.

BACKGROUND: This study aimed to assess the fertility intentions of young people after the announcement of the three-child policy in China and to determine whether knowledge about reproductive, maternal, newborn, and child health (RMNCH) services or support, childbearing- and childbirth-related anxiety, and parenthood-related anxiety influence fertility intentions. METHODS: A cross-sectional Internet-based survey was conducted on a nationwide sample of young people aged 18 to 28 years old in education institutions. Factors associated with fertility intentions were analysed using partial least squares structural equation modelling (PLS-SEM). RESULTS: Only 4.2% of males and 1.7% of females intended to have three children or more. On the whole, the majority (40.3%) reported the intention to have two children. The mean and standard deviation (SD) for the total knowledge RMNCH support and/or services knowledge score was 9.5 (SD ± 8.9), out of a possible score of 39. The median and interquartile range (IQR) of childbearing- and childbirth-related anxiety score was 8.0 (IQR = 6.0-9.0), out of a possible score of 10. The median and IQR of parenthood-related anxiety score among the males was 6.0 (IQR = 4.0-9.0) and for females was 7.0 (IQR = 5.0-9.0). Results from PLS-SEM revealed that a higher level of knowledge of RMNCH support and/or services is significantly associated with higher fertility intentions. Both childbearing- and childbirth-related anxiety and parenthood-related anxiety were inversely associated with fertility intentions. CONCLUSION: Raising awareness about RMNCH supportive measures and easing birth- and parenting anxiety are imperative to enhance birth rates. Future policies should pay more attention to these determinants to achieve their intended goal of boosting population growth.

Observing a previously hidden structural-phase transition onset through heteroepitaxial cap response.

Characterization of the onset of a phase transition is often challenging due to the fluctuations of the correlation length scales of the order parameters. This is especially true for second-order structural-phase transition due to minute changes involved in the relevant lattice constants. A classic example is the cubic-to-tetragonal second-order phase transition in SrTiO3 (STO), which is so subtle that it is still unresolved. Here, we demonstrate an approach to resolve this issue by epitaxially grown rhombohedral La0.7Sr0.3MnO3 (LSMO) thin films on the cubic STO (100) substrate. The shear strain induced nanotwinning waves in the LSMO film are extremely sensitive to the cubic-to-tetragonal structural-phase transitions of the STO substrate. Upon cooling from room temperature, the development of the nanotwinning waves is spatially inhomogeneous. Untwinned, atomically flat domains, ranging in size from 100 to 300 nm, start to appear randomly in the twinned phase between 265 and 175 K. At ∼139 K, the untwinned, atomically flat domains start to grow rapidly into micrometer scale and finally become dominant at ∼108 K. These results indicate that the low-temperature tetragonal precursor phase of STO has already nucleated at 265 K, significantly higher than the critical temperature of STO (∼105 K). Our work paves a pathway to visualize the onset stages of structural-phase transitions that are too subtle to be observed using direct-imaging methods.

Mussel-Inspired Surface Functionalization of PET with Zwitterions and Silver Nanoparticles for the Dual-Enhanced Antifouling and Antibacterial Properties.

Herein, we designed and constructed a dual functional surface with antimicrobial and antifouling abilities to prevent protein and bacterial attachment that are significant challenges in biomedical devices. Primary amino-group-capped sulfobetaine of DMMSA was synthesized and then grafted onto polydopamine pretreated PET sheets via click chemistry. The sheets were subsequently immersed into silver ion solution, in which the absorbed silver ions were reduced to silver nanoparticles (AgNPs) in situ by a polydopamine layer. The antifouling assays demonstrated that the resultant PET/DMMSA/AgNPs sheets exhibited great antifouling performances against bovine serum albumin (BSA), bovine fibrinogen (BFG), platelets, and bacteria, the critical proteins/microorganisms leading to implant failure. The antibacterial data suggested that the sheets had dual functions as inhibitors of bacterial growth and bactericide and could efficiently delay the biofilm formation. This repelling and killing approach is green and simple, with potential biomedical applications.

Emerging single-phase state in small manganite nanodisks.

In complex oxides systems such as manganites, electronic phase separation (EPS), a consequence of strong electronic correlations, dictates the exotic electrical and magnetic properties of these materials. A fundamental yet unresolved issue is how EPS responds to spatial confinement; will EPS just scale with size of an object, or will the one of the phases be pinned? Understanding this behavior is critical for future oxides electronics and spintronics because scaling down of the system is unavoidable for these applications. In this work, we use La0.325Pr0.3Ca0.375MnO3 (LPCMO) single crystalline disks to study the effect of spatial confinement on EPS. The EPS state featuring coexistence of ferromagnetic metallic and charge order insulating phases appears to be the low-temperature ground state in bulk, thin films, and large disks, a previously unidentified ground state (i.e., a single ferromagnetic phase state emerges in smaller disks). The critical size is between 500 nm and 800 nm, which is similar to the characteristic length scale of EPS in the LPCMO system. The ability to create a pure ferromagnetic phase in manganite nanodisks is highly desirable for spintronic applications.

Unexpected Intermediate State Photoinduced in the Metal-Insulator Transition of Submicrometer Phase-Separated Manganites.

At ultrafast timescales, the initial and final states of a first-order metal-insulator transition often coexist forming clusters of the two phases. Here, we report an unexpected third long-lived intermediate state emerging at the photoinduced first-order metal-insulator transition of La_{0.325}Pr_{0.3}Ca_{0.375}MnO_{3}, known to display submicrometer length-scale phase separation. Using magnetic force microscopy and time-dependent magneto-optical Kerr effect, we determined that the third state is a nanoscale mixture of the competing ferromagnetic metallic and charge-ordered insulating phases, with its own physical properties. This discovery bridges the two different families of colossal magnetoresistant manganites known experimentally and shows for the first time that the associated states predicted by theory can coexist in a single sample.

Manipulating electronic phase separation in strongly correlated oxides with an ordered array of antidots.

The interesting transport and magnetic properties in manganites depend sensitively on the nucleation and growth of electronic phase-separated domains. By fabricating antidot arrays in La0.325Pr0.3Ca0.375MnO3 (LPCMO) epitaxial thin films, we create ordered arrays of micrometer-sized ferromagnetic metallic (FMM) rings in the LPCMO films that lead to dramatically increased metal-insulator transition temperatures and reduced resistances. The FMM rings emerge from the edges of the antidots where the lattice symmetry is broken. Based on our Monte Carlo simulation, these FMM rings assist the nucleation and growth of FMM phase domains increasing the metal-insulator transition with decreasing temperature or increasing magnetic field. This study points to a way in which electronic phase separation in manganites can be artificially controlled without changing chemical composition or applying external field.

Lesion based diagnostic performance of dual phase 99mTc-MIBI SPECT/CT imaging and ultrasonography in patients with secondary hyperparathyroidism.

BACKGROUND: We aimed to evaluate the diagnostic performance of 99mTc-MIBI SPECT/CT and ultrasonography in patients with secondary hyperparathyroidism (SHPT), and explored the factors that affect the diagnostic performance. METHODS: 99mTc-MIBI SPECT/CT and ultrasonography were performed in 50 patients with SHPT within 1 month before they underwent surgery. Imaging results were confirmed by the pathology. Pearson correlation analysis was used to determine the correlation of PTH level with clinical data. The optimal cutoff value for predicting positive 99mTc-MIBI results was evaluated by ROC analysis in lesions diameter. RESULTS: Forty-nine patients had a positive 99mTc-MIBI imaging results and 39 patients had positive ultrasonography results. The sensitivities of 99mTc-MIBI and ultrasonography were 98.00% and 78.00%, respectively. A total of 199 lesions were resected in 50 patients. Among them, 183 lesions were proved to be parathyroid hyperplasia. On per-lesion basis analysis, the sensitivity and specificity of 99mTc-MIBI and ultrasonography were 59.34% and 75.00% vs 46.24% and 80.00%, respectively. The Pearson correlation analysis showed that the serum AKP and PTH level had a significant linear association (r = 0.699, P < 0.001). The lesion diameter was a statistically significant predictive factor in predicting positive 99mTc-MIBI SPECT/CT. The optimal cutoff value for predicting positive 99mTc-MIBI results evaluated by ROC analysis in lesions diameter was 8.05 mm. CONCLUSION: Dual phase 99mTc-MIBI SPECT/CT imaging had a higher sensitivity in patients with SHPT than ultrasonography. Therefore, using 99mTc-MIBI positioning the lesion could be an effective method pre-surgical in patients with SHPT.

Cerebral blood perfusion changes in amputees with myoelectric hands after rehabilitation: a SPECT computer-aided analysis.

BACKGROUND: Rehabilitation, which is essential for amputees with myoelectric hands, can improve the quality of daily life by remodeling the neuron network. In our study, we aim to develop a cerebral blood perfusion (CBF) single-photon emission computed tomography computer-aided (SPECT-CA) detection scheme to automatically locate the brain's activated regions after rehabilitation. RESULTS: Five participants without forearms (three male, two female, mean age 51 ± 12.89 years, two missing the right side, and three missing the left side) were included in our study. In the clinical assessment, all of the participants received higher scores after training. The results of the SPM analysis indicated that CBF in the precentral gyrus, postcentral gyrus, frontal lobe, temporal lobe and cerebellum was significantly different among the five participants (P < 0.05). Moreover, SPECT-CA showed that the activated brain areas mainly included the precentral gyrus, postcentral gyrus, cerebellum and extensive cerebral cortex. CONCLUSION: Our study demonstrated that the CBF SPECT-CA method can detect the brain blood perfusion changes induced by rehabilitation with high sensitivity and accuracy. This method has great potential for locating the remodeled neuron regions of amputees with myoelectric hands after rehabilitation.

Biometabolic Distribution of 99mTc-3PRGD2 and Its Potential Value in Monitoring Chemotherapeutic Effects.

Previous studies have reported that 99mTc-3PRGD2 is an excellent tumor imaging agent that showed a good correlation with integrin αvß3, a main factor of tumor-induced angiogenesis. In this study, we investigated the biometabolic distribution characteristics of 99mTc-3PRGD2 with a continuous dynamic acquisition mode to explore the potential value of 99mTc-3PRGD2 in monitoring chemotherapeutic effects in VX2 tumor models. Eighteen rabbits with 27 implanted VX2 squamous cell tumors were randomly divided into a nontreated control group (NTG, n = 8; 12 tumors) and a treatment group (TG, n = 10; 15 tumors). 99mTc-3PRGD2 imaging was performed prior to cisplatin injection and repeated on days 0, 1, 7, and 14 postinjection. Continuous dynamic scanning up to 30 minutes; static imaging at 0.5 hours, 1 hour, and 3 hours; and single-photon emission computed tomography/computed tomography (SPECT/CT)-integrated imaging at 3 hours post-99mTc-3PRGD2 injection were performed. The peak time (time to reach peak in dynamic curve), tumor to normal (T/N) ratios, and their change rates relative to pretherapy were calculated. Autoradiography, hematoxylin-eosin (H&E) staining, and CD31 and integrin αv immunohistochemical staining were examined. VX2 tumors were clearly visualized at 3 hours post-99mTc-3PRGD2 injection. Tumors in the TG shrank significantly on day 7 after cisplatin administration (p < .05). The half-life (t1/2) of the radiotracer in heart, liver, and tumor in the NTG were 3.43 ± 0.94 minutes, 13.41 ± 9.17 minutes, and 70.83 ± 33.37 minutes, respectively. The peak time was delayed in the TG immediately and continuously after cisplatin administration compared to the peak time in the NTG. The T/N values and their change rates decreased significantly in the TG compared to the NTG after therapy (p < .05). The immunostained areas were significantly decreased in the TG (p < .05) compared to the NTG. 99mTc-3PRGD2 was an excellent imaging agent for demonstrating tumor angiogenesis. The peak time, T/N values, and their change rates were sensitive parameters to monitor early chemotherapeutic effects. Due to the specific target mechanism and the cost-effective value of 99mTc-3PRGD2, 99mTc-3PRGD2 SPECT imaging may have potential in detecting the therapeutic effects of anticancer therapy.

Polarization-dependent photoinduced metal-insulator transitions in manganites.

In correlated oxides, collaborative manipulation on light intensity, wavelength, pulse duration and polarization has yielded many exotic discoveries, such as phase transitions and novel quantum states. In view of potential optoelectronic applications, tailoring long-lived static properties by light-induced effects is highly desirable. So far, the polarization state of light has rarely been reported as a control parameter for this purpose. Here, we report polarization-dependent metal-to-insulator transition (MIT) in phase-separated manganite thin films, introducing a new degree of freedom to control static MIT. Specifically, we observed giant photoinduced resistance jumps with striking features: (1) a single resistance jump occurs upon a linearly polarized light incident with a chosen polarization angle, and a second resistance jump occurs when the polarization angle changes; (2) the amplitude of the second resistance jump depends sensitively on the actual change of the polarization angles. Linear transmittance measurements reveal that the origin of the above phenomena is closely related to the coexistence of anisotropic micro-domains. Our results represent a first step to utilize light polarization as an active knob to manipulate static phase transitions, pointing towards new pathways for nonvolatile optoelectronic devices and sensors.

Smart photothermal-triggered bilayer phase transition in AuNPs-liposomes to release drug.

Novel thermosensitive liposomes with embedded Au nanoparticles (AuNPs) in the liposome bilayer were prepared by a combination method of film build and supercritical CO(2) incubation. These AuNPs-liposomes possess AuNPs that are embedded in the bilayer and a drug that is encapsulated in the central aqueous compartment. The AuNPs in the liposomes can strongly absorb light energy and efficiently convert the absorbed energy to heat. The localized heat induces a phase transition in the liposome bilayer and releases the drug. The drug release from the AuNPs-liposomes can be controlled by the irradiation time and AuNPs concentration in the AuNPs-liposomes at room temperature, where the AuNPs function as a nanoswitch for triggering drug release both spatially and temporally. The results suggest that drug release from the AuNPs-liposomes is due to a photothermic effect that induces phase transition of the liposomes rather than destruction of the liposome bilayer.

Electronically phase separated nano-network in antiferromagnetic insulating LaMnO3/PrMnO3/CaMnO3 tricolor superlattice.

Strongly correlated materials often exhibit an electronic phase separation (EPS) phenomena whose domain pattern is random in nature. The ability to control the spatial arrangement of the electronic phases at microscopic scales is highly desirable for tailoring their macroscopic properties and/or designing novel electronic devices. Here we report the formation of EPS nanoscale network in a mono-atomically stacked LaMnO3/CaMnO3/PrMnO3 superlattice grown on SrTiO3 (STO) (001) substrate, which is known to have an antiferromagnetic (AFM) insulating ground state. The EPS nano-network is a consequence of an internal strain relaxation triggered by the structural domain formation of the underlying STO substrate at low temperatures. The same nanoscale network pattern can be reproduced upon temperature cycling allowing us to employ different local imaging techniques to directly compare the magnetic and transport state of a single EPS domain. Our results confirm the one-to-one correspondence between ferromagnetic (AFM) to metallic (insulating) state in manganite. It also represents a significant step in a paradigm shift from passively characterizing EPS in strongly correlated systems to actively engaging in its manipulation.

Pharmacokinetics, efficacy, and safety evaluation of docetaxel/hydroxypropyl-sulfobutyl-ß-cyclodextrin inclusion complex.

Hydroxypropyl-sulfobutyl-ß-cyclodextrin (HP-SBE-ß-CD) inclusion complex was developed and used as a drug delivery system for DTX (DTX/HP-SBE-ß-CD). The objective of the present study was to evaluate and compare the biological properties of DTX/HP-SBE-Β-CD with Taxotere®. The pharmacokinetics, biodistribution, antitumor efficacy in vivo and in vitro, and safety evaluation of DTX/HP-SBE-ß-CD were studied. The most significant finding was that it was possible to prepare a Polysorbate-80-free inclusion complex for DTX. Studies based on pharmacokinetics, biodistribution, and antitumor efficacy indicated that DTX/HP-SBE-ß-CD had similar pharmacokinetic properties and antitumor efficacy both in vitro and in vivo as Taxotere®. Fortunately, this new drug delivery system attenuated the side effects when used in vivo. As a consequence, DTX/HP-SBE-ß-CD may be a promising alternative to Taxotere® for cancer chemotherapy treatment with reduced side effects. The therapeutic potential against a variety of human tumors and low toxicity demonstrated in a stringent study clearly warrant clinical investigation of DTX/HP-SBE-ß-CD for possible use against human tumors.

Pulsed laser deposition of large-sized superlattice films with high uniformity.

Oxide superlattices often exhibit emergent physical properties that are desirable for future information device applications. The most common growth technique for fabrication of oxide superlattices is pulsed laser deposition (PLD), which is convenient yet powerful for the growth of various oxide superlattices. However, the sample size prepared by PLD is rather small confined by the plasmon plume, which greatly limits its potential for device applications. Here, we design a PLD system that is capable of fabricating large-sized oxide superlattices with high uniformity. Specifically, during growth, the laser beam scans the target surface by combining the pitch and yaw angle rotation of the high reflective mirror and the linear motion of the focus lens. A SiC susceptor is placed in between the sample holder and the substrate to improve the large area infrared heating efficiency. Using such a system, droplet-free 10 × 10 mm2 [(LSMO)12/(PCMO)6]7 superlattices are epitaxially grown with the same period of superlattices across the whole sample areas. The high uniformity of the superlattices is further illustrated by near identical physical properties of all regions of the superlattice films. The present PLD system can be used to grow various kinds of oxide superlattices with the area size as large as 2 in., which is highly useful for device applications of oxides.

Facile fabrication of sheet-on-sheet hierarchical nanostructured Sb/C composite with boosting sodium storage.

Rational design and facile synthesis of two-dimensional (2D) materials still remain a great challenge. Herein, a facile process was proposed to construct 2D porous hybrid nanosheets, with ultrathin antimony nanoplates (with a thickness of ca. 0.5 nm) being anchored on acetone-derived graphene-like carbon porous nanosheets, by an aldol reaction and subsequent carbothermal reduction method using acetone and antimony acetate as the starting raw materials. The novel structural and compositional characteristics afford the 2D porous hybrid nanosheets with impressive boosting electrochemical sodium storage properties in terms of excellent cycling stability, high reversible specific capacity, and superior rate performance. The present work would provide significant value for the development of both synthetic methodology of 2D materials and their application as electrode active materials for energy storage and conversion.

One-step preparation of molybdenum disulfide/graphene nano-catalysts through a simple co-exfoliation method for high-performance electrocatalytic hydrogen evolution reaction.

HYPOTHESIS: Recently, molybdenum disulfide (MoS2) as a new type of catalyst, has been used for hydrogen evolution. In order to overcome the shortcomings of MoS2, such as poor conductivity and lack of catalytic activity sites, various materials were added to prepare composites, such as graphene with good conductivity. EXPERIMENTS: In this work, we combined MoS2 with graphene through a very simple liquid-phase salt-assisted co-exfoliation method. The obtained MoS2/graphene nano-composites have been further applied to electrocatalyst of hydrogen evolution reaction. The influences of different ratio of MoS2 to graphene and different solvents of exfoliation on the electrocatalytic activity for the hydrogen evolution reaction have been investigated in detail. FINDINGS: In general, the obtained MoS2/graphene nano-catalysts exhibits the smallest Tafel slope of 61 mV/dec with the exfoliation solvent of isopropanol, and 65 mV/dec in N-methyl pyrrolidone. All the MoS2/graphene composites exhibit much better catalytic activity than either MoS2 or graphene single substance due to the synergetic effect between MoS2 and graphene nanosheets.

Achieving large and nonvolatile tunable magnetoresistance in organic spin valves using electronic phase separated manganites.

Tailoring molecular spinterface between novel magnetic materials and organic semiconductors offers promise to achieve high spin injection efficiency. Yet it has been challenging to achieve simultaneously a high and nonvolatile control of magnetoresistance effect in organic spintronic devices. To date, the largest magnetoresistance (~300% at T = 10 K) has been reached in tris-(8-hydroxyquinoline) aluminum (Alq3)-based organic spin valves (OSVs) using La0.67Sr0.33MnO3 as a magnetic electrode. Here we demonstrate that one type of perovskite manganites, i.e., a (La2/3Pr1/3)5/8Ca3/8MnO3 thin film with pronounced electronic phase separation (EPS), can be used in Alq3-based OSVs to achieve a large magnetoresistance (MR) up to 440% at T = 10 K and a typical electrical Hanle effect as the Hallmark of the spin injection. The contactless magnetic field-controlled EPS enables us to achieve a nonvolatile tunable MR response persisting up to 120 K. Our study suggests a new route to design high performance multifunctional OSV devices using electronic phase separated manganites.