Tracing the dynamics of superconducting order via transient terahertz third-harmonic generation.

Ultrafast optical control of quantum systems is an emerging field of physics. In particular, the possibility of light-driven superconductivity has attracted much of attention. To identify nonequilibrium superconductivity, it is necessary to measure fingerprints of superconductivity on ultrafast timescales.

Formation mechanism of Ruddlesden-Popper faults in compressive-strained ABO perovskite superlattices.

Ruddlesden-Popper (RP) faults have emerged as a promising candidate for defect engineering in epitaxial ABO perovskites. Functionalities could be fine-tuned by incorporating RP faults into ABO thin films and superlattices. However, due to the lattice expansion at AO-AO interfaces, it is generally believed that RP faults are only energetically favorable under tensile strain.

The Interaction between Reactive Peritoneal Mesothelial Cells and Tumor Cells via Extracellular Vesicles Facilitates Colorectal Cancer Dissemination.

Advanced colorectal cancer (CRC) is highly metastatic and often results in peritoneal dissemination. The extracellular vesicles (EVs) released by cancer cells in the microenvironment are important mediators of tumor metastasis. We investigated the contribution of EV-mediated interaction between peritoneal mesothelial cells (MCs) and CRC cells in generating a pro-metastatic environment in the peritoneal cavity.

Phase-resolved Higgs response in superconducting cuprates.

In high-energy physics, the Higgs field couples to gauge bosons and fermions and gives mass to their elementary excitations. Experimentally, such couplings can be inferred from the decay product of the Higgs boson, i.e.

High-Temperature Thermoelectricity in LaNiO-LaCuO Heterostructures.

Transition metal oxides exhibit a high potential for application in the field of electronic devices, energy storage, and energy conversion. The ability of building these types of materials by atomic layer-by-layer techniques provides a possibility to design novel systems with favored functionalities. In this study, by means of the atomic layer-by-layer oxide molecular beam epitaxy technique, we designed oxide heterostructures consisting of tetragonal KNiF-type insulating LaCuO (LCO) and perovskite-type conductive metallic LaNiO (LNO) layers with different thicknesses to assess the heterostructure-thermoelectric property-relationship at high temperatures.

High-temperature superconductivity at the lanthanum cuprate/lanthanum-strontium nickelate interface.

The utilization of interface effects in epitaxial systems at the nanoscale has emerged as a very powerful approach for engineering functional properties of oxides. Here we present a novel structure fabricated by a state-of-the-art oxide molecular beam epitaxy method and consisting of lanthanum cuprate and strontium (Sr)-doped lanthanum nickelate, in which interfacial high-temperature superconductivity (Tc up to 40 K) occurs at the contact between the two phases. In such a system, we are able to tune the superconducting properties simply by changing the structural parameters.

Dopant size effects on novel functionalities: High-temperature interfacial superconductivity.

Among the range of complex interactions, especially at the interfaces of epitaxial oxide systems, contributing to the occurrence of intriguing effects, a predominant role is played by the local structural parameters. In this study, oxide molecular beam epitaxy grown lanthanum cuprate-based bilayers (consisting of a metallic (M) and an insulating phase (I)), in which high-temperature superconductivity arises as a consequence of interface effects, are considered. With the aim of assessing the role of the dopant size on local crystal structure and chemistry, and on the interface functionalities, different dopants (Ca, Sr and, Ba) are employed in the M-phase, and the M-I bilayers are investigated by complementary techniques, including spherical-aberration-corrected scanning transmission electron microscopy.

Cationic Redistribution at Epitaxial Interfaces in Superconducting Two-Dimensionally Doped Lanthanum Cuprate Films.

The exploration of interface effects in complex oxide heterostructures has led to the discovery of novel intriguing phenomena in recent years and has opened the path toward the precise tuning of material properties at the nanoscale. One recent example is space-charge superconductivity. Among the complex range of effects which may arise from phase interaction, a crucial role is played by cationic intermixing, which defines the final chemical composition of the interface.

Atomic-Scale Quantitative Analysis of Lattice Distortions at Interfaces of Two-Dimensionally Sr-Doped La2CuO4 Superlattices.

Using spherical aberration corrected high-resolution and analytical scanning transmission electron microscopy, we have quantitatively studied the lattice distortion and the redistribution of charges in two-dimensionally strontium (Sr)-doped La2CuO4 superlattices, in which single LaO planes are periodically replaced by SrO planes. As shown previously, such structures show Tc up to 35 K as a consequence of local charge accumulation on both sides of the nominal SrO planes position. This is caused by two distinct mechanisms of doping: heterogeneous doping at the downward side of the interface (space-charge effect) and "classical" homogeneous doping at the upward side.

High-temperature superconductivity in space-charge regions of lanthanum cuprate induced by two-dimensional doping.

The exploitation of interface effects turned out to be a powerful tool for generating exciting material properties. Such properties include magnetism, electronic and ionic transport and even superconductivity. Here, instead of using conventional homogeneous doping to enhance the hole concentration in lanthanum cuprate and achieve superconductivity, we replace single LaO planes with SrO dopant planes using atomic-layer-by-layer molecular beam epitaxy (two-dimensional doping).

Tunable Charge and Spin Order in PrNiO_{3} Thin Films and Superlattices.

We use polarized Raman scattering to probe lattice vibrations and charge ordering in 12 nm thick, epitaxially strained PrNiO_{3} films, and in superlattices of PrNiO_{3} with the band insulator PrAlO_{3}. A carefully adjusted confocal geometry is used to eliminate the substrate contribution to the Raman spectra. In films and superlattices under tensile strain which undergo a metal-insulator transition upon cooling, the Raman spectra reveal phonon modes characteristic of charge ordering.

Orbital control of noncollinear magnetic order in nickel oxide heterostructures.

We have used resonant x-ray diffraction to develop a detailed description of antiferromagnetic ordering in epitaxial superlattices based on two-unit-cell thick layers of the strongly correlated metal LaNiO3. We also report reference experiments on thin films of PrNiO3 and NdNiO3. The resulting data indicate a spiral state whose polarization plane can be controlled by adjusting the Ni d-orbital occupation via two independent mechanisms: epitaxial strain and spatial confinement of the valence electrons.

Element specific monolayer depth profiling.

The electronic phase behavior and functionality of interfaces and surfaces in complex materials are strongly correlated to chemical composition profiles, stoichiometry and intermixing. Here a novel analysis scheme for resonant X-ray reflectivity maps is introduced to determine such profiles, which is element specific and non-destructive, and which exhibits atomic-layer resolution and a probing depth of hundreds of nanometers.

Layer selective control of the lattice structure in oxide superlattices.

A combined synchrotron X-ray diffraction and transmission electron microscopy study reveals a structural phase transition controlled by the overall thickness of epitaxial nickelate-aluminate superlattices. The transition between uniform and twin-domain states is confined to the nickelate layers and leaves the aluminate layers unaffected.

Dimensionality control of electronic phase transitions in nickel-oxide superlattices.

The competition between collective quantum phases in materials with strongly correlated electrons depends sensitively on the dimensionality of the electron system, which is difficult to control by standard solid-state chemistry. We have fabricated superlattices of the paramagnetic metal lanthanum nickelate (LaNiO(3)) and the wide-gap insulator lanthanum aluminate (LaAlO(3)) with atomically precise layer sequences. We used optical ellipsometry and low-energy muon spin rotation to show that superlattices with LaNiO(3) as thin as two unit cells undergo a sequence of collective metal-insulator and antiferromagnetic transitions as a function of decreasing temperature, whereas samples with thicker LaNiO(3) layers remain metallic and paramagnetic at all temperatures.

Orbital reflectometry of oxide heterostructures.

The occupation of d orbitals controls the magnitude and anisotropy of the inter-atomic electron transfer in transition-metal oxides and hence exerts a key influence on their chemical bonding and physical properties. Atomic-scale modulations of the orbital occupation at surfaces and interfaces are believed to be responsible for massive variations of the magnetic and transport properties, but could not thus far be probed in a quantitative manner. Here we show that it is possible to derive quantitative, spatially resolved orbital polarization profiles from soft-X-ray reflectivity data, without resorting to model calculations.

Giant superconductivity-induced modulation of the ferromagnetic magnetization in a cuprate-manganite superlattice.

Artificial multilayers offer unique opportunities for combining materials with antagonistic orders such as superconductivity and ferromagnetism and thus to realize novel quantum states. In particular, oxide multilayers enable the utilization of the high superconducting transition temperature of the cuprates and the versatile magnetic properties of the colossal-magnetoresistance manganites. However, apart from exploratory work, the in-depth investigation of their unusual properties has only just begun.

Orbital reconstruction and covalent bonding at an oxide interface.

Orbital reconstructions and covalent bonding must be considered as important factors in the rational design of oxide heterostructures with engineered physical properties. We have investigated the interface between high-temperature superconducting (Y,Ca)Ba(2)Cu3O7 and metallic La(0.67)Ca(0.

[Preliminary experiences on triscaphoid arthrodesis].

The authors report their experience of 5 patients (4 males, 1 female) with a mean age of 36.4 years (min 25 years, max 45 years), undergoing triscaphoid arthrodesis between May 1989 and August 1993. The patients suffered from rotatory dislocation of the scaphoid (1 case) and stage 3A of Kienboeck's disease according to Lichtman's classification (4 cases).

Partial arthrodeses of the wrist.

The authors report 16 cases of partial arthrodeses of the wrist for the treatment of Kienboeck's disease, pseudarthrosis of the scaphoid, rotatory subluxation of the scaphoid, rheumatoid arthritis, etc. Based on the good results obtained (76.6%) the authors believe that partial arthrodeses constitute the type of treatment indicated for the treatment of pathologies that involve only some of the carpal bones, and they also emphasize that this type of surgery represents a valid alternative to total arthrodesis of the wrist.

Replantation and revascularization of large segments of the hand and forearm.

From November 1985 to July 1989, the authors performed replantation or revascularization surgery on 18 patients in whom a large segment of the upper limb between the elbow and the palm of the hand had been either completely severed (9 cases) or incompletely severed with ischemia (9 cases). The operation was successful in 16 cases, and the authors were able to clinically review 14 patients (average follow-up, 23 months). The results were analyzed using a protocol based on the following parameters: range of motion, sensation, muscle strength, cold intolerance, pain, return to work, cosmesis, and the patient's level of satisfaction.

Hemangioma of the hand.

The authors describe the anatomopathological and clinical findings of 24 cases of benign hemangioma of the hand. The instrumental methods used to diagnose hemangioma are discussed, and MRI imaging is given particular importance in the preoperative evaluation of the site, size, extent, and relationship with the surrounding tissues and any multiple locations of the vascular tumor. This evaluation is essential to perform a wide resection of the tumor, which is the only means of avoiding recurrence.

Epidemiological and structural findings supporting the fibromatous origin of dorsal knuckle pads.

Epidemiological, optical and electron microscopical findings suggest that dorsal knuckle pads and Dupuytren's disease are fibrosing disorders with common features. In all cases examined, knuckle pads were always associated with Dupuytren's contracture and, in a significant number of cases, with bilateral Dupuytren's contracture. In a statistically significant number of patients with knuckle pads, Ledderhose's and Peyronie's diseases were also present (P less than 0.

High testosterone levels of ovarian origin affect adrenal steroidogenesis?

Androgens of ovarian origin have been suggested to affect adrenal enzymatic activity. To investigate this possibility, the 17-hydroxyprogesterone (17-OH P) and cortisol (F) responses to an ACTH stimulation test (0.25 mg iv, bolus) were evaluated in 10 normal women and in 39 hyperandrogenic women with normal (14 subjects) or high (25 subjects) testosterone (T) levels.