Ultra-wide range non-contact surface profilometry based on reconfigurable fiber interferometry.

Surface characterization is essential for a technical evaluation of device performance and to assess surface dynamics in fabrication units. In this regard, a number of surface profiling techniques have been developed that accurately map sample topography but have significantly limited detection range. Here, we demonstrate a cascaded non-contact fiber interferometer-based approach for real-time high-precision surface profiling with ultrawide detection range (nm to mm). This compact interferometers' system operates by wavelength interrogation that provides a scope to study several types of surfaces and has a tunable cavity configuration for varying the sensitivity and range of the detectable features' size. The proposed system enables nanoscale profiling over 10-1000 nm with resolution of 10 nm and microscale mapping over 1-1000 µm with resolution of 0.2 µm. The technique is utilized to map the features of nanostructured surfaces and estimate the surface roughness of standardized industrial samples.

Bone Fracture-healing Properties and UPLC-MS Analysis of an Enriched Flavonoid Fraction from Oxystelma esculentum.

Oxystelma esculentum has been used as a folk medicine to treat jaundice, throat infections, and skin problems. In the current study, the bone fracture-healing properties of a flavonoid-enriched fraction (Oxy50-60F) of O. esculentum were investigated in Swiss mice using a drill-hole injury model. Oxy50-60F (1 mg/kg/day, 5 mg/kg/day, and 10 mg/kg/day) was administered orally (from the next day) after a 0.6 mm drill-hole injury in mice femur mid-diaphysis for 7 days and 14 days. Parathyroid hormone (40 µg/kg; 5 times/week) was given subcutaneously as the positive control. Confocal imaging for bone regeneration, micro-architecture of femur bones, ex vivo mineralization, hematoxyline and eosin staining, measurement of reactive oxygen species, and gene expression of osteogenic and anti-inflammatory genes were studied. Quercetin, kaempferol, and isorhamnetin glycosides were identified in the active fraction using mass spectrometry techniques. Our results confirm that Oxy50-60F treatment promotes fracture healing and callus formation at drill-hole sites and stimulates osteogenic and anti-inflammatory genes. Oxy50-60F administration to fractured mice exhibited significantly better micro-CT parameters in a dose-dependent manner and promoted nodule mineralization at days 7 and 14 post-injury. Oxy50-60F also prevents ROS generation by increasing expression of the SOD2 enzyme. Overall, this study reveals that Oxy50-60F has bone regeneration potential in a cortical bone defect model, which supports its use in delayed-union and non-union fracture cases.

Palladium-Catalyzed Dearomative [4 + 2]-Cycloaddition toward Hydrocarbazoles.

An efficient method for the construction of hydrocarbazoles bearing three continuous sterically hindered stereocenters, two quaternary and one tertiary, via a highly diastereoselective palladium-catalyzed [4 + 2]-cycloaddition/dearomatization of 3-nitroindoles has been developed. The cycloaddition of 3-nitroindoles occurs at ambient conditions with a 1,4-zwitterionic intermediate, in situ generated from γ-methylidene-δ-valerolactones. The further synthetic utility of this method is demonstrated by the multifaceted transformations possible from the products. The catalytic asymmetric aspect of this transformation has also been explored.

Enhanced conduction band density of states in intermetallic EuTSi3 (T = Rh, Ir).

We report on the physical properties of single crystalline EuRhSi3 and polycrystalline EuIrSi3, inferred from magnetization, electrical transport, heat capacity and (151)Eu Mössbauer spectroscopy. These previously known compounds crystallise in the tetragonal BaNiSn3-type structure. The single crystal magnetization in EuRhSi3 has a strongly anisotropic behaviour at 2 K with a spin-flop field of 13 T, and we present a model of these magnetic properties which allows the exchange constants to be determined. In both compounds, specific heat shows the presence of a cascade of two close transitions near 50 K, and the (151)Eu Mössbauer spectra demonstrate that the intermediate phase has an incommensurate amplitude modulated structure. We find anomalously large values, with respect to other members of the series, for the RKKY Néel temperature, for the spin-flop field (13 T), for the spin-wave gap (≃20-25 K) inferred from both resistivity and specific heat data, for the spin-disorder resistivity in EuIrSi3 (≃240 µΩ cm) and for the saturated hyperfine field (52 T). The enhanced values of the quantities that depend on the electronic density of states at the Fermi level, imply that the latter must be strongly enhanced in these two materials. EuIrSi3 exhibits a giant magnetoresistance ratio, with values exceeding 600% at 2 K in a field of 14 T.

Magnetic anisotropy, unusual hysteresis and putative "up-up-down" magnetic structure in EuTAl4Si2 (T = Rh and Ir).

We present detailed investigations on single crystals of quaternary EuRhAl4Si2 and EuIrAl4Si2. The two compounds order antiferromagnetically at TN1 = 11.7 and 14.7 K, respectively, each undergoing two magnetic transitions. The magnetic properties in the ordered state present a large anisotropy despite Eu(2+)being an S-state ion for which the single-ion anisotropy is expected to be weak. Two features in the magnetization measured along the c-axis are prominent. At 1.8 K, a ferromagnetic-like jump occurs at very low field to a value one third of the saturation magnetization (1/3 M0) followed by a wide plateau up to 2 T for Rh and 4 T for Ir-compound. At this field value, a sharp hysteretic spin-flop transition occurs to a fully saturated state (M0). Surprisingly, the magnetization does not return to origin when the field is reduced to zero in the return cycle, as expected in an antiferromagnet. Instead, a remnant magnetization 1/3 M0 is observed and the magnetic loop around the origin shows hysteresis. This suggests that the zero field magnetic structure has a ferromagnetic component, and we present a model with up to third neighbor exchange and dipolar interaction which reproduces the magnetization curves and hints to an "up-up-down" magnetic structure in zero field.

Synthesis, crystal and electronic structure of the quaternary magnetic EuTAl4Si2 (T = Rh and Ir) compounds.

Single crystals of the quaternary europium compounds EuRhAl4Si2 and EuIrAl4Si2 were synthesized by using the Al-Si binary eutectic as a flux. The structure of the two quaternary compounds has been refined by single crystal X-ray diffraction. Both compounds are stoichiometric and adopt an ordered derivative of the ternary KCu4S3 structure type (tetragonal tP8, P4/mmm). The two compounds reported here represent the first example of a quaternary and truly stoichiometric 1:1:4:2 phase crystallizing with this structure type. In light of our present results, the structure of the BaMg4Si3 compound given in literature as representing a new prototype is actually isotypic with the KCu4S3 structure. Local spin density approximation including the Hubbard U parameter (LSDA + U) calculations show that Eu ions are in the divalent state, with a significant hybridization between the Eu 5d, Rh (Ir) 4d (5d), Si 3p and Al 3p states. Magnetic susceptibility measured along the [001] direction confirms the divalent nature of the Eu ions in EuRhAl4Si2 and EuIrAl4Si2, which order magnetically near ∼11 and ∼15 K, respectively.

Anisotropic magnetic properties and crystal electric field studies on CePd2Ge2 single crystal.

The anisotropic magnetic properties of the antiferromagnetic compound CePd2Ge2, crystallizing in the tetragonal crystal structure have been investigated in detail on a single crystal grown by the Czochralski method. From the electrical transport, magnetization and heat capacity data, the Néel temperature is confirmed to be 5.1 K. Anisotropic behaviour of the magnetization and resistivity is observed along the two principal crystallographic directions-namely, [100] and [001]. The isothermal magnetization measured in the magnetically ordered state at 2 K exhibits a spin reorientation at 13.5 T for the field applied along the [100] direction, whereas the magnetization is linear along the [001] direction attaining a value of 0.94 µ(B)/Ce at 14 T. The reduced value of the magnetization is attributed to the crystalline electric field (CEF) effects. A sharp jump in the specific heat at the magnetic ordering temperature is observed. After subtracting the phononic contribution, the jump in the heat capacity amounts to 12.5 J K(-1)mol(-1) which is the expected value for a spin ½ system. From the CEF analysis of the magnetization data the excited crystal field split energy levels were estimated to be at 120 K and 230 K respectively, which quantitatively explains the observed Schottky anomaly in the heat capacity. A magnetic phase diagram has been constructed based on the field dependence of magnetic susceptibility and the heat capacity data.