Ir 5d-band derived superconductivity in LaIr3

The superconducting properties of rhombohedral LaIr₃ were examined using susceptibility, resistivity, heat capacity, and zero-field (ZF) and transverse-field (TF) muon spin relaxation and rotation ([Formula: see text]SR) measurements. The susceptibility and resistivity measurements confirm a superconducting transition below [Formula: see text] K. Two successive transitions are observed in the heat capacity data, one at [Formula: see text] K and a second at 1.2 K below [Formula: see text]. The heat capacity jump is [Formula: see text], which is lower than 1.43 expected for Bardeen-Cooper-Schrieffer (BCS) weak-coupling limit. TF-[Formula: see text]SR measurements reveal a fully gapped s-wave superconductivity with [Formula: see text], which is small compared to the BCS value of 3.56, suggesting weak-coupling superconductivity. The magnetic penetration depth, [Formula: see text], estimated from TF-[Formula: see text]SR gives [Formula: see text] nm, a superconducting carrier density [Formula: see text] carriers m^-3 and a carrier effective-mass enhancement factor [Formula: see text]. ZF-[Formula: see text]SR data show no evidence for any spontaneous magnetic fields below [Formula: see text], which demonstrates that time-reversal symmetry is preserved in the superconducting state of LaIr₃.

Correction: Three-dimensional directional nerve guide conduits fabricated by dopamine-functionalized conductive carbon nanofibre-based nanocomposite ink printing

Correction for ’Three-dimensional directional nerve guide conduits fabricated by dopamine-functionalized conductive carbon nanofibre-based nanocomposite ink printing’ by Shadi Houshyar et al., RSC Adv., 2020, 10, 40351–40364, DOI: 10.1039/D0RA06556K.

Three-dimensional directional nerve guide conduits fabricated by dopamine-functionalized conductive carbon nanofibre-based nanocomposite ink printing

Directional growth induced by dopamine-functionalized CNF-based nanocomposite ink printing.

Effect of nanocomposite coating and biomolecule functionalization on silk fibroin based conducting 3D braided scaffolds for peripheral nerve tissue engineering

In this work, the effects of carbon nanofiber (CNF) dispersed poly-ε-caprolactone (PCL) nanocomposite coatings and biomolecules functionalization on silk fibroin based conducting braided nerve conduits were studied for enhancing Neuro 2a cellular activities. A unique combination of biomolecules (UCM) and varying concentrations of CNF (5, 7.5, 10% w/w) were dispersed in 10% (w/v) PCL solution for coating on degummed silk threads. The coated silk threads were braided to develop the scaffold structure. As the concentration of CNF increased in the coating, the electrical impedance decreased up to 400 Ω indicating better conductivity. The tensile and dynamic mechanical property analysis showed better mechanical properties in CNF coated samples. In vitro cytocompatibility analysis proved the non-toxicity of the developed braided conduits. Cell attachment, growth and proliferation were significantly enhanced on the biomolecule functionalized nanocomposite coated silk braided structure, exhibiting their potential for peripheral nerve regeneration and recovery.

Stability, Crystal Chemistry, and Magnetism of U2+xNi21-xB6 and Nb3-yNi20+yB6 and the Role of Uranium in the Formation of the Quaternary U2-zNbzNi21B6 and UδNb3-δNi20B6 Systems

We investigated the U-Ni-B and Nb-Ni-B systems to search for possible new heavy fermion compounds and superconducting materials. The formation, crystal chemistry, and physical properties of U₂Ni₂₁B₆ and Nb_3-yNi_20+yB₆ [ternary derivatives of the cubic Cr₂₃C₆-type (cF116, Fm3̅m)] have been studied; the formation of the hypothetical "U₃Ni₂₀B₆" and "Nb₂Ni₂₁B₆" has been disproved. U₂Ni₂₁B₆ [a = 10.6701(2) Å] crystallizes in the ordered W₂Cr₂₁C₆-type, whereas Nb_3-yNi_20+yB₆ [a = 10.5842(1) Å] adopts the Mg₃Ni₂₀B₆-type. Ni in U₂Ni₂₁B₆ can be substituted by U, leading to the solid solution U_2+xNi_21-xB₆ (0 ≤ x ≤ 0.3); oppositely, Nb in Nb₃Ni₂₀B₆ is partially replaced by Ni, forming the solution Nb_3-yNi_20+yB₆ (0 ≤ y ≤ 0.5), none of them reaching the limit corresponding to the hypothetically ordered "U₃Ni₂₀B₆" and "Nb₂Ni₂₁B₆". These results prompted us to investigate quaternary compounds U_2-zNb_zNi₂₁B₆ and U_δNb_3-δNi₂₀B₆: strong competition in the occupancy of the 4a and 8c sites by U, Nb, and Ni atoms has been observed, with the 4a site occupied by U/Ni atoms only and the 8c site filled by U/Nb atoms only. U₂Ni₂₁B₆, U_2.3Ni_20.7B₆, and Nb₃Ni₂₀B₆ are Pauli paramagnets. Interestingly, Nb_2.5Ni_20.5B₆ shows ferromagnetism with T_C ≈ 11 K; the Curie-Weiss fit gives an effective magnetic moment of 2.78 μ_B/Ni, suggesting that all Ni atoms in the formula unit contribute to the total magnetic moment. The M(H) data at 2 K further corroborate the ferromagnetic behavior with a saturation moment of 10 μ_B/fu (≈0.49 μ_B/Ni). The magnetic moment of Ni at the 4a site induces a moment in all of the Ni atoms of the whole unit cell (32f and 48h sites), with all atoms ordering ferromagnetically at 11 K. Density functional theory (DFT) shows that the formation of U₂Ni₂₁B₆ and Nb₃Ni₂₀B₆ is energetically preferred. The various electronic states generating ferromagnetism on Nb_2.5Ni_20.5B₆ and Pauli paramagnetism on U₂Ni₂₁B₆ and Nb₃Ni₂₀B₆ have been identified.

Peripheral Nerve Conduit: Materials and Structures

Peripheral nerve injuries (PNIs) are the most common injury types to affect the nervous system. Restoration of nerve function after PNI is a challenging medical issue. Extended gaps in transected peripheral nerves are only repaired using autologous nerve grafting. This technique, however, in which nerve tissue is harvested from a donor site and grafted onto a recipient site in the same body, has many limitations and disadvantages. Recent studies have revealed artificial nerve conduits as a promising alternative technique to substitute autologous nerves. This Review summarizes different types of artificial nerve grafts used to repair peripheral nerve injuries. These include synthetic and natural polymers with biological factors. Then, desirable properties of nerve guides are discussed based on their functionality and effectiveness. In the final part of this Review, fabrication methods and commercially available nerve guides are described.

Unveiling spin-glass transition and antiferromagnetic order by μSR studies in spin-chain Sm2BaNiO5

We report the zero-field and longitudinal field muon spin relaxation studies in a spin-chain compound Sm₂BaNiO₅. Two magnetic transitions, that have not been previously detected by the heat capacity and magnetization measurements, are confirmed at 46 and 9 K. The antiferromagnetic order is suggested at 46 K. Analysis of the muon spin polarization unveils the spin-glass transition at 9 K. Time-field scaling relation of the muon spin polarization verifies the spin-spin autocorrelation function following the cut-off power law, which is approximated by the Ogielski form, as employed numerically for characterizing the spin-glasses.

Evidence of a Nodal Line in the Superconducting Gap Symmetry of Noncentrosymmetric ThCoC_{2}

The newly discovered noncentrosymmetric superconductor ThCoC_{2} exhibits numerous types of unconventional behavior in the field dependent heat capacity data. Here we present the first measurement of the gap symmetry of ThCoC_{2} by muon spin rotation and relaxation (μSR) measurements. The temperature dependence of the magnetic penetration depth measured using the transverse field μSR experiment reveals the evidence of a nodal pairing symmetry. To understand this finding, we carry out calculations of the superconducting pairing eigenvalue and eigenfunction (pairing symmetry) due to the spin-fluctuation mechanism by directly implementing the ab initio band structures. We find that the system possesses a single Fermi surface with considerable three dimensionality and a strong nesting along the k_{z} direction. Such nesting promotes a superconducting state with a cosk_{z}-like pairing symmetry with a prominent nodal line on the k_{z}=±π/2 plane. The result agrees well with the experimental data.

Complexation of U(VI) with Cucurbit[5]uril: Thermodynamic and Structural investigation in aqueous medium

The assessment of cucurbituril (CBn) for selective removal of actinides from nuclear waste streams requires comprehensive understanding of binding parameters and coordination of these complexes. The present work is the first experimental report on complexation of actinide ion with Cucurbit[5]uril (CB5) in solution. The thermodynamic parameters (ΔG, ΔH and ΔS) for complexation of CB5 with U(VI) in formic acid water medium were determined using microcalorimetry and UV-Vis spectroscopy. The enthalpy and entropy of complexation revealed the partial binding of U(VI) to CB5 portal. The partial binding was confirmed by spectroscopic techniques viz. extended X absorption fine structure spectroscopy (EXAFS), ¹H and ¹³C NMR. The EXAFS χ(r) versus r spectra for U-CB5 complex has been fitted from 1.4 to 3.5 Å with two oxygen shells and a carbon shell. The presence of three carbon atom in secondary shell shows the involvement of only three carbonyl oxygens directly bonding to U(VI) which is in contrast to that calculated from gas phase DFT calculation of unhydrated system. The combined effect of hydration and formic acid encapsulation led to the enhanced stability of partially bound U(VI) to CB5. In the present work the binding of formic acid has also been studied by fluorescence spectroscopy. ESI-MS data shows the unusual stabilization of U(VI) by CB5 in gas phase.

Magnetic structure and field-dependent magnetic phase diagram of Ni2In-type PrCuSi

The magnetic structure of the ternary equiatomic intermetallic compound PrCuSi is investigated using neutron powder diffraction experiments in 0 T as well as in external magnetic fields up to 2 T. The PrCuSi compound crystallizes in the hexagonal Ni₂In-type structure, in the space group P6₃/mmc. In this structure, cationic ordering of Cu and Si takes place. The antiferromagnetic phase transition in the Pr sublattice takes place at [Formula: see text] K in 0 T. Under an external magnetic field of 2 T, a field-induced ferromagnetic phase is observed. Magnetoelastic coupling is evidenced by an increase in the unit cell volume. Clear signatures of a mixed antiferromagnetic and ferromagnetic phase in weak, intermediate fields, 0.4-0.8 T, are obtained from the present study. Using the present set of experimental data, we construct the H  -  T phase diagram of PrCuSi.

In vitro evaluation of phytochemical loaded electrospun gelatin nanofibers for application in bone and cartilage tissue engineering

Wattakaka volubilis, a medicinal plant, is known to exhibit various potential health benefits and has traditionally been used in Ayurveda for various medicinal applications. In the present study, phytochemicals hexadecanoic acid, octadecanoic acid and N,N-Diisopropyl(2,2,3,3,3-pentafluoropropyl)amine isolated from W. volubilis leaf extract were co-electrospun with gelatin nanofibers for meniscus and osteoblast cell attachment and proliferation. The electrospun nanofibers were characterized using suitable techniques such as a scanning electron microscope and Fourier transform infrared spectroscopy. The mechanical property of electrospun gelatin nanofibers and phytochemicals incorporated gelatin nanofibers were tensile tested. Both the control and phytochemical loaded nanofiber exhibited a similar stress-strain trend. The average diameter of the control and phytocompound loaded gelatin nanofiber was found to be 300 ± 5.5 nm and 483 ± 12 nm, respectively. The rate of biodegradation of the control and phytochemical loaded nanofiber was analyzed in a simulated body fluid. The cell attachment and proliferation were monitored using a fluorescence microscope after appropriate staining. The cell viability, DNA content, extracellular secretion confirmed that the phytocompound loaded gelatin nanofibers were non-toxic and enhanced the meniscus and osteoblast cell growth and proliferation. This phytocompound loaded gelatin matrix may be used as a potential scaffold for cartilage and bone tissue engineering applications.

Human Knee Meniscus Regeneration Strategies: a Review on Recent Advances

PURPOSE OF REVIEW

Lack of vascularity in the human knee meniscus often leads to surgical removal (total or partial meniscectomy) in the case of severe meniscal damage. However, complete recovery is in question after such removal as the meniscus plays an important role in knee stability. Thus, meniscus tissue regeneration strategies are of intense research interest in recent years.

RECENT FINDINGS

The structural complexity and inhomogeneity of the meniscus have been addressed with processing technologies for precisely controlled three dimensional (3D) complex porous scaffold architectures, the use of biomolecules and nanomaterials. The regeneration and replacement of the total meniscus have been studied by the orthopedic and scientific communities via successful pre-clinical trials towards mimicking the biomechanical properties of the human knee meniscus. Researchers have attempted different regeneration strategies which contribute to in vitro regeneration and are capable of repairing meniscal tears to some extent. This review discusses the present state of the art of these meniscus tissue engineering aspects.

Effect of dietary manipulation and vaccination of turkey breeder hens on immunoglobulin levels of yolk, yolk sac and neonate poults

Two hundred turkey breeder hens and 24 viable toms of 30-35 weeks age of small white variety were distributed into two treatment groups having four replicates of 25 hens and three toms in each treatment. First four replicates were offered a turkey breeder diet (Diet A) (Nutrient requirements of poultry, 1994, National Academic Press, Washington, DC) and the rest four replicates were maintained on a higher plane of nutrition (Diet B) for 8-week duration. After 6 weeks of experimental feeding, two replicates from each treatment groups were vaccinated with ND (R₂ B) vaccine. Yolk sac of embryo from birds fed Diet B had a significantly higher (p < .05) IgG, IgM level and HI titre (log 2) than those fed Diet A. HI titre values of embryonic yolk sac from the vaccinated birds fed Diet B were significantly higher (p < .05) than that of the control groups. In addition, HI titre values were significantly higher (p < .05) in the day-old poults of the birds fed Diet B than that of those fed Diet A. There was significantly (p < .01) positive correlation between serum IgG and IgM of the breeder birds and day-old chicks. Similarly, there was significantly (p < .05) positive correlation between yolk IgG and IgM after 1-month experimental feeding and yolk sac IgG and IgM. Positive correlation (p < .05) also existed between yolk sac IgM and day-old chick serum IgM. Furthermore, the HI titres of breeder birds' serum at 14 days post-vaccination were positively correlated with their egg yolk after 10 and 15 days post-vaccination, yolk sac and day-old chicks. Thus, the study envisaged that a higher immunity in neonate poults from turkey breeders maintained on a higher plane of nutrition may be elicited as there was maternal transfer of antibodies from the serum of breeder birds to their offsprings through their yolk sac.