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Tetsuro Tominaga, Takashi Nonaka, Shosaburo Oyama, Yuma Takamura, Shintaro Hashimoto, Toshio Shiraishi, Terumitsu Sawai, Takeshi Nagayasu Department of Surgical Oncology, Nagasaki University Graduate School of Biomedical Science, Nagasaki, JapanCorrespondence: Tetsuro Tominaga, Department of Surgical Oncology, Nagasaki University Graduate School of Biological Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan, Tel +81-95-819-7304, Fax +81-95-819-7306, Email tetsuro.tominaga@nagasaki-u.ac.jpPurpose: The prognostic value of neutrophil-to-lymphocyte ratio (NLR) has been studied for colorectal cancer. Elderly patients in general tend to have comorbidities and decreased organ function that potentially influence the NLR score. The aim of this study was to investigate the relationship between NLR and cancer-specific survival in elderly patients with colon cancer, using a propensity score-matched analysis.Patients and Methods: A total of 203 patients aged over 75 years who underwent curative resection for colon cancer and were diagnosed pathologically with stage II/III disease were eligible for entry to the study. Patients were divided into two groups according to NLR score: NLR-High (NLR≥ 4.5) group (NLR-H, n=60) and NLR-Low (NLR< 4.5) group (NLR-L, n=143). After propensity score matching, 57 patients in each group were matched.Results: Before matching, Charlson comorbidity index was significantly higher in the NLR-H group (4 vs 2, p< 0.001). After matching, all factors were similar between the groups. The median follow-up period was 43 months (range, 1– 160 months). Five-year relapse-free-survival (69.8% vs 87.3%, p=0.030) and cancer-specific survival (83.0% vs 96.0%, p=0.042) were significantly lower in the NLR-H group.Conclusion: NLR appears to be a cancer-specific prognostic marker in elderly patients with colon cancer.Keywords: cancer-specific survival, colon cancer, neutrophil-to-lymphocyte ratio

Takeshi Tomomatsu, Shinjiro Kono, Shogo Arimura, Yoko Tomomatsu, Takehiro Matsumura, Yuji Takihara, Masaru Inatani, Yoshihiro TakamuraDepartment of Ophthalmology, Faculty of Medical Sciences, University of Fukui, Fukuiken, JapanObjectives: To evaluate the contribution of axial length, and lenticular and corneal power to the spherical equivalent refractive error in children with hyperopia between 3 and 13 years of age, using noncontact optical biometry.Methods: There were 62 children between 3 and 13 years of age with hyperopia (+2 diopters [D] or more) who underwent automated refraction measurement with cycloplegia, to measure spherical equivalent refractive error and corneal power. Axial length was measured using an optic biometer that does not require contact with the cornea. The refractive power of the lens was calculated using the Sanders-Retzlaff-Kraff formula. Single regression analysis was used to evaluate the correlation among the optical parameters.Results: There was a significant positive correlation between age and axial length (P = 0.0014); however, the degree of hyperopia did not decrease with aging (P = 0.59). There was a significant negative correlation between age and the refractive power of the lens (P = 0.0001) but not that of the cornea (P = 0.43). A significant negative correlation was observed between the degree of hyperopia and lenticular power (P < 0.0001).Conclusion: Although this study is small scale and cross sectional, the analysis, using noncontact biometry, showed that lenticular power was negatively correlated with refractive error and age, indicating that lower lens power may contribute to the degree of hyperopia.Keywords: emmetropization, axial length

Topotactic transformations involve structural changes between related crystal structures due to a loss or gain of material while retaining a crystallographic relationship. The perovskite oxide La0.7Sr0.3CoO3 (LSCO) is an ideal system for investigating phase transformations due to its high oxygen vacancy conductivity, relatively low oxygen vacancy formation energy, and strong coupling of the magnetic and electronic properties to the oxygen stoichiometry. While the transition between cobaltite perovskite and brownmillerite (BM) phases has been widely reported, further reduction beyond the BM phase lacks systematic studies. In this paper, we study the evolution of the physical properties of LSCO thin films upon exposure to highly reducing environments. We observe the rarely reported crystalline Ruddlesden-Popper phase, which involves the loss of both oxygen anions and cobalt cations upon annealing where the cobalt is found as isolated Co ions or Co nanoparticles. First-principles calculations confirm that the concurrent loss of oxygen and cobalt ions is thermodynamically possible through an intermediary BM phase. The strong correlation of the magnetic and electronic properties to the crystal structure highlights the potential of utilizing ion migration as a basis for emerging applications such as neuromorphic computing.

The ability to systematically modify the magnetic properties of epitaxial La0.7Sr0.3MnO3 thin films is demonstrated through the use of Ar+ ion implantation. With increasing implant dose, a uniaxial expansion of the c-axis of the unit cell leads to a transition from in-plane toward perpendicular magnetic anisotropy. Above a critical dose of 3 × 1013 Ar+/cm2, significant crystalline disorder exists leading to a decrease in the average Mn valence state and near complete suppression of magnetization. Combined with lithographic techniques, ion implantation enables the fabrication of magnetic spin textures consisting of adjacent regions with tunable magnetic anisotropy in complex oxide thin films.

We present a study of the physical properties of perovskite oxide Nd0.5Sr0.5MnO3 (NSMO) thin films grown on (110)-oriented SrTiO3 substrates. In bulk form, NSMO displays coupled magnetic and electronic transitions from paramagnetic/insulator to ferromagnetic (FM)/metal and then to antiferromagnetic (AFM)/charge-ordered insulator with decreasing temperature. In thin films, the AFM ordering only occurs when the films exist in an anisotropic strain state such as those obtained on (110)-oriented cubic substrates. In this work, resonant X-ray reflectivity, soft X-ray photoemission electron microscopy (X-PEEM), and magnetometry measurements showed that the NSMO film displays both vertical and lateral magnetic phase separation. Specifically, the film consists of three layers with different density and magnetic properties. The FM and AFM properties of the main NSMO layer were probed as a function of temperature using soft X-ray magnetic spectroscopy, and the coexistence of lateral FM and AFM domains was demonstrated at 110 K using X-PEEM.

Complex oxide heterostructures provide access to emergent functional and structural phases which are not present in the bulk constituent materials. In this Rapid Communication, we focus on La0.67Sr0.33CoO3 (LSCO)/Gd heterostructures due to the high oxygen ion conductivity, as well as the coupled magnetic and electronic properties of LSCO, which are strongly dependent on the oxygen stoichiometry. This combination of properties enables the ionic control of the functional properties of LSCO thin films through the presence of oxygen getter layers such as Gd. We utilize X-ray nanodiffraction to directly image the nanoscale morphology of LSCO thin films as they are progressively transformed from the equilibrium perovskite phase to the metastable brownmillerite (BM) phase with increasing Gd thickness. Our studies show the coexistence of perovskite and BM phases with a critical oxygen vacancy concentration threshold which leads to the formation of extended BM filaments. In addition to lateral phase separation, we observed phase separation within the film thickness possibly due to pinning of the perovskite and BM phases by the substrate/LSCO and LSCO/Gd interface, respectively. Our studies provide a nanoscale survey of the phase separation in the cobaltites and shed light on the formation of the metastable BM phase.

Heterointerfaces introduce unique localized defects into ionic conductors. This study explores the nanoionic characteristics exhibited by the proton-conducting oxides SrZr 0.9 Y 0.1 O 3-δ and SrCe 0.95 Yb 0.05 O 3-δ including finely dispersed precipitated platinum nanoparticles. The electrical conductivity of both the platinum-doped oxides revealed reversible nanoionic phenomena caused by the exsolution of the platinum in the form of platinum nanoparticles, at 0.5 vol% relative to the metal oxides, and dissolution in response to a change in gas atmosphere. In comparison with the original conductivity of SrZr 0.9 Y 0.1 O 3-δ and SrCe 0.95 Yb 0.05 O 3-δ , the conductivity of platinum-doped SrZr 0.9 Y 0.1 O 3-δ decreased significantly in a wet hydrogen atmosphere, whereas platinum-doped SrCe 0.95 Yb 0.05 O 3-δ showed almost no decrease in conductivity in the same atmosphere. The different responses of the two materials to the change in gas atmosphere are discussed in relation to the precipitation of platinum nanoparticles.

Magnetic properties arising at interfaces of perovskite oxides such as La 0.7 Sr 0.3 CoO 3 (LSCO) and La 0.7 Sr 0.3 MnO 3 (LSMO) depend sensitively on the fine details of their structural properties. In this work, we use high-resolution transmission electron microscopy and spectroscopy to examine the structural and electronic phenomena at the interfaces in two LSCO/LSMO bilayers with reversed growth order. Two different strain mechanisms are at work in these films: compressive or tensile epitaxial strain, and distortion of the octahedral tilt pattern to maintain a network of corner-sharing octahedra. While the epitaxial strain is constant regardless of the growth order, the modification of the octahedral tilt pattern depends on whether the film is grown directly on the substrate or as the second sublayer. As a consequence, exchange spring behavior is observed only when the LSCO sublayer is grown first. The different mechanisms of strain accommodation within the oxygen octahedra network in each material proved to be of critical importance in determining the interfacial structure and thus magnetic and electronic properties of the bilayers.

A wedge bilayer of epitaxial 4-8 nm La0.7Sr0.3CoO3(LSCO)/6-nm La0.7Sr0.3MnO3(LSMO), hard and soft ferromagnets (FM) respectively, was studied using soft x-ray magnetic spectroscopy to elucidate the interplay between the magnetic and electronic properties of the constituent layers. This system exhibits magnetic and electronic segregation within the LSCO layer characterized by soft FM Co2+ ions at the interface (s-LSCO), which is biased by the underlying hard LSCO layer (h-LSCO), characterized by predominantly Co3+/Co4+ FM ions. For a 5.1-nm layer, the interfacial Co2+ ion concentration is maximized and the h-LSCO coercivity is minimized, while the opposite is true for a 7.8-nm LSCO layer. These dual trends in Co2+ ion concentration and h-LSCO coercivity within the LSCO serve to independently affect the exchange bias and coercivity of the soft FM layer, resulting in inverse trends between these properties that typically vary simultaneously.

Control of materials through custom design of ionic distributions represents a powerful new approach to develop future technologies ranging from spintronic logic and memory devices to energy storage. Perovskites have shown particular promise for ionic devices due to their high ion mobility and sensitivity to chemical stoichiometry. In this work, we demonstrate a solid-state approach to control of ionic distributions in (La,Sr)CoO3 thin films. Depositing a Gd capping layer on the perovskite film, oxygen is controllably extracted from the structure, up to 0.5 O/u.c. throughout the entire 36-nm thickness. Commensurate with the oxygen extraction, the Co valence state and saturation magnetization show a smooth continuous variation. In contrast, magnetoresistance measurements show no change in the magnetic anisotropy and a rapid increase in the resistivity over the same range of oxygen stoichiometry. These results suggest significant phase separation, with metallic ferromagnetic regions and oxygen-deficient, insulating, nonferromagnetic regions, forming percolated networks. Indeed, x-ray diffraction identifies oxygen-vacancy ordering, including transformation to a brownmillerite crystal structure. The unexpected transformation to the brownmillerite phase at ambient temperature is further confirmed by high-resolution scanning transmission electron microscopy which shows significant structural - and correspondingly chemical - phase separation. This work demonstrates room-temperature ionic control of magnetism, electrical resistivity, and crystalline structure in a 36-nm-thick film, presenting opportunities for ionic devices that leverage multiple material functionalities.

β-Ga2O3 thin films were grown on n-type GaN substrates using the sol–gel method. The forward-biased temperature dependent current–voltage (I–V–T) characteristics of Ni/β-Ga2O3/GaN structure have been investigated in the temperature range of 298–473 K. The apparent barrier height (ϕap) increased while the ideality factor (n) decreased with the increase in temperature. Such a temperature dependent behavior of ϕap and n was explained by the inhomogeneity of ϕap, which obeyed Gaussian distribution with zero-bias mean barrier height (ϕ¯ B0) of 1.02 ± 0.02 eV and standard deviation (σs0) of 153 ± 0.04 mV. Subsequently, ϕ¯ B0 and Richardson constant A* were obtained from the slope and intercept of the modified Richardson plot as 0.99 ± 0.01 e V and 67.2 A cm−2 K−2, respectively. The ϕ¯ B0 obtained from the modified Richardson plot was in good agreement with the theoretical value calculated from the work function of Ni and electron affinity of β-Ga2O3. The I–V–T characteristics of Ni/β-Ga2O3/GaN MOS structures can be successfully explained by the thermionic emission theory with a single Gaussian distribution of the barrier height.

The magnetic structure of exchange-coupled antiferromagnetic (AF) layers in epitaxial La 0.7 Sr 0.3 MnO 3 (LSMO)/La 0.7 Sr 0.3 FeO 3 (LSFO) superlattices grown on (111)-oriented SrTiO 3 substrates was studied using angle-dependent x-ray absorption spectroscopy utilizing linearly polarized x rays. We demonstrate the development of the measurement protocols needed to determine the orientation of the LSFO antiferromagnetic spin axis and how it responds to an applied magnetic field due to exchange interactions with an adjacent ferromagnetic layer. A small energy difference exists between two types of AF order: the majority of the AF moments cant out-of-the-plane of the film along the 110 or 100 directions depending on the LSFO layer thickness. In response to an applied magnetic field, these canted moments are aligned with a single 110 or 100 direction that maintains a nearly perpendicular orientation relative to the LSMO sublayer magnetization. The remaining AF moments lie within the (111) plane and these in-plane moments can be reoriented to an arbitrary in-plane direction to lie parallel to the LSMO sublayer magnetization. These results demonstrate that the magnetic order of AF thin films and heterostructures is far more complex than in bulk LSFO and can be tuned with orientation, thickness, and applied magnetic field.

We have used soft x-ray photoemission electron microscopy to image the magnetization of single-domain La0.7Sr0.3MnO3 nanoislands arranged in geometrically frustrated configurations such as square ice and kagome ice geometries. Upon thermal randomization, ensembles of nanoislands with strong interisland magnetic coupling relax towards low-energy configurations. Statistical analysis shows that the likelihood of ensembles falling into low-energy configurations depends strongly on the annealing temperature. Annealing to just below the Curie temperature of the ferromagnetic film (TC=338K) allows for a much greater probability of achieving low-energy configurations as compared to annealing above the Curie temperature. At this thermally active temperature of 325 K, the ensemble of ferromagnetic nanoislands explore their energy landscape over time and eventually transition to lower energy states as compared to the frozen-in configurations obtained upon cooling from above the Curie temperature. Thus, this materials system allows for a facile method to systematically study thermal evolution of artificial spin ice arrays of nanoislands at temperatures modestly above room temperature.

Soft x-ray photoemission electron microscopy with an in situ magnetic field has been used to study the relationship between ferromagnetic and antiferromagnetic spin alignment and the switching/reversal field of epitaxial micromagnetic structures. We investigated a model system consisting of a bilayer of ferromagnetic La0.7Sr0.3MnO3 and antiferromagnetic LaFeO3 where the spin axes in each layer can be driven from mutually perpendicular (spin-flop) to parallel alignment by varying the temperature between 30 and 300 K. Results show that not only does this spin alignment noticeably influence the bilayer micromagnet coercivity compared to La0.7Sr0.3MnO3 single-layer micromagnets, but the coercivity within this materials system can be tuned over a wide range by careful balance of material properties.

In this paper, β-Ga2O3 thin films were grown on a p-Si substrate using the sol-gel method. Structural characterization of the films was performed using X-ray diffraction. Electrical parameters such as breakdown field, interface traps density (Dit), and series resistance (Rs) were investigated at room temperature. The interface trap density was found to be 1012 eV-1 cm-2 using the Hill-Coleman method. This result is valuable for MOS capacitor applications. Dielectric parameters were investigated in the wide frequency range (20 kHz-1 MHz) at room temperature. We observed that these parameters have a strong dependence on frequency and voltage.

The thickness-dependent magnetic and electrical transport properties of nearly strain-free La0.7Sr0.3CoO3 (LSCO) films grown on (001)-oriented (LaAlO3)0.3 (Sr2AlTaO6)0.7 substrates were systematically studied. A crossover from ferromagnetic/metallic to non-magnetic/insulating behavior occurs at a critical thickness (∼8 nm) that is significantly smaller than LSCO films under larger strains in reported literature. X-ray absorption measurements revealed that the difference of functional properties at reduced film thicknesses was accompanied by changes in the valence state of Co ions at the film/substrate interface.

The impact of interfacial electronic reconstruction on the magnetic characteristics of La0.7Sr0.3CoO3 (LSCO)/La0.7Sr0.3MnO3 (LSMO) heterostructures was investigated as a function of layer thickness using a combination of soft x-ray magnetic spectroscopy and bulk magnetometry. We found that the magnetic properties of the LSCO layers are impacted by two competing electronic interactions occurring at the LSCO/substrate and LSMO/LSCO interfaces. For thin LSCO layers (

Epitaxial La0.7Sr0.3MnO3(LSMO)/La0.7Sr0.3FeO3 (LSFO) superlattices on (111)-oriented SrTiO3 substrates with sublayer thicknesses ranging from 3 to 60 unit cells (u.c.) were synthesized and characterized. Detailed analysis of their structural, electronic, and magnetic properties were performed to explore the effect of sublayer thickness on the magnetic structure and exchange coupling at (111)-oriented perovskite oxide interfaces. In the ultrathin limit (3-6 u.c.), we find that the antiferromagnetic (AF) properties of the LSFO sublayers are preserved with an out-of-plane canting of the AF spin axis, while the ferromagnetic (FM) properties of the LSMO sublayers are significantly depressed. For thicker LSFO layers (>9 u.c.), the out-of-plane canting of the AF spin axis is only present in superlattices with thick LSMO sublayers. As a result, exchange coupling in the form of spin-flop coupling exists only in superlattices which display both robust ferromagnetism and out-of-plane canting of the AF spin axis.

Using soft x-ray spectromicroscopy, we investigate the magnetic domain structure in embedded nanomagnets defined in La0.7Sr0.3MnO3 thin films and LaFeO3/La0.7Sr0.3MnO3 bilayers. We find that shape-controlled antiferromagnetic domain states give rise to a significant reduction of the switching field of the rectangular nanomagnets. This is discussed within the framework of competition between an intrinsic spin-flop coupling and shape anisotropy. The data demonstrates that shape effects in antiferromagnets may be used to control the magnetic properties in nanomagnets.

Epitaxial La0.7Sr0.3MnO3(LSMO)/La0.7Sr0.3FeO3 (LSFO) superlattices serve as model systems to explore the magnetic structure and exchange coupling at (111)-oriented perovskite oxide interfaces. The (111) orientation possesses a buckled honeycomb structure resembling that of graphene with the stacking of highly polar layers. Furthermore, the bulk LSFO magnetic structure suggests that an ideal (111) interface should have fully uncompensated antiferromagnetic (AF) moments leading to exchange bias interactions. Detailed soft x-ray magnetic spectroscopy and microscopy reveal that interfacial effects and ultrathin superlattice sublayers can stabilize orientations of the LSFO AF spin axis, which differ from that of LSFO films and LSMO/LSFO bilayers. A portion of the AF moments can be reoriented to an arbitrary direction by a moderate external magnetic field through spin-flop coupling with the ferromagnetic LSMO sublayers that have low magnetocrystalline anisotropy in the (111) plane.

Epitaxial strain is a powerful tool to induce functional properties such as ferroelectricity in thin films of materials that do not possess ferroelectricity in bulk form. In this work, a ferroelectric state was stabilized in thin films of the incipient ferroelectric, CaTiO3, through the careful control of the biaxial strain state and TiO6 octahedral rotations. Detailed structural characterization was carried out by synchrotron x-ray diffraction and scanning transmission electron microscopy. CaTiO3 films grown on La0.18Sr0.82Al0.59Ta0.41O3 (LSAT) and NdGaO3 (NGO) substrates experienced a 1.1% biaxial strain state but differed in their octahedral tilt structures. A suppression of the out-of-plane rotations of the TiO6 octahedral in films grown on LSAT substrates resulted in a robust ferroelectric I4?mm phase with remnant polarization ∼5?μC/cm2 at 10?K and Tc near 140?K. In contrast, films grown on NGO substrates with significant octahedral tilting showed reduced polarization and Tc. These results highlight the key role played by symmetry in controlling the ferroelectric properties of perovskite oxide thin films.

We report on the observation of exchange-spring behavior in complex oxide bilayers composed of high coercivity ferromagnetic (FM) La0.7Sr0.3CoO3 (LSCO) and low coercivity FM La0.7Sr0.3MnO3 (LSMO). The magnetization process from each individual layer is revealed by a combination of bulk magnetometry and x-ray magnetic circular dichroism measurements. The results show unexpected magnetic switching behavior which deviates from conventional exchange-spring systems in that reversible switching occurs not only within the soft LSMO layer but is also accompanied by the switching of an interfacial LSCO layer. The origin of such exchange coupling is discussed in terms of charge redistribution at the interface.

Differing anisotropic strain induced from the underlying substrates not only control the long-range structural symmetries in La0.5Sr0.5CoO3 but also impact the magnetic properties of these epitaxial thin films. The two dominant structural distortions: oxygen octahedral tilts and epitaxial strain, however, have complex and non-intuitive effects on the splitting of the t2g states and consequently on magnetization.

We investigate the effects of strain on antiferromagnetic (AFM) single crystal thin films of La1-xSrxMnO3 (x = 0.6). Nominally unstrained samples have strong magnetoresistance with anisotropic magnetoresistances (AMR) of up to 8%. Compressive strain suppresses magnetoresistance but generates AMR values of up to 63%. Tensile strain presents the only case of a metal-insulator transition and demonstrates a previously unreported AMR behavior. In all three cases, we find evidence of magnetic ordering and no indication of a global ferromagnetic phase transition. These behaviors are attributed to epitaxy induced changes in orbital occupation driving different magnetic ordering types. Our findings suggest that different AFM ordering types have a profound impact on the AMR magnitude and character. © 2014 Author(s).

Unlike other 3d transition metal monoxides (MnO, FeO, CoO, and NiO), CuO is found in a low-symmetry distorted monoclinic structure rather than the rocksalt structure. We report here of the growth of ultrathin CuO films on SrTiO3 substrates; scanning transmission electron microscopy was used to show the stabilization of a tetragonal rocksalt structure with an elongated c-axis such that and the Cu-O-Cu bond angle , pointing to metastable six-fold coordinated Cu. X-ray absorption spectroscopy demonstrates that the hole at the Cu site for the CuO is localized in orbital unlike the well-studied monoclinic CuO phase. The experimental confirmation of the tetragonal structure of CuO opens up new avenues to explore electronic and magnetic properties of six-fold coordinated Cu. © Copyright EPLA, 2014.

A recent theoretical study [Phys. Rev. B 85, 121411(R) (2012)] predicted a thickness limit below which ideal polar cuprates turn nonpolar driven by the associated electrostatic instability. Here we demonstrate this possibility by inducing a structural transformation from the bulk planar to chainlike structure upon reducing the SrCuO2 repeat thickness in SrCuO2/SrTiO3 superlattices with unit-cell precision. Our results, based on structural investigation by x-ray diffraction and high resolution scanning transmission electron microscopy, demonstrate that the oxygen sublattice can essentially be built by design. In addition, the electronic structure of the chainlike structure, as studied by x-ray absorption spectroscopy, shows the signature for preferential hole occupation in the Cu 3d(3z2-r2) orbital, which is different from the planar case.

The formation process of hexagonal boron nitride (hBN) monolayer sheets on single-crystalline ZrB2(0001) thin films grown on Si(111) wafers has been investigated by electron diffraction, scanning tunneling microscopy, and photoelectron spectroscopy. A two-step reaction was identified, resulting first in the formation of a silicon nitride layer by room temperature exposure of the silicene-terminated ZrB2 thin film surface to nitrogen radicals and then in the formation of an hBN monolayer replacing the silicon nitride layer through annealing at 900 °C. A large-scale moiré pattern and a clear dispersion of the π-electronic band provide evidence for the formation of an epitaxial hBN monolayer sheet directly on the diboride surface. The unique ability of the ZrB2(0001) surface, upon which both silicene and hBN monolayers can be formed, opens a way toward the integration of these two very different two-dimensional materials. [ABSTRACT FROM AUTHOR]