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We report on the spectroscopic identification of tetramethylenedisulfotetramine (TETS), a deadly neurotoxic rodenticide, captured on plasmonic substrates using supramolecular guest-host functionality. Commercial nanopatterned surface-enhanced Raman spectroscopy (SERS) active substrates were self-assembled with host β-cyclodextrin (CD) and the captured TETS was readily identified by X-ray photoelectron (XPS) and infrared spectroscopy, but not with Raman. Density functional theory (DFT) calculation was carried out to determine the Raman scattering cross section of TETS to gauge its Raman scattering efficiency in the preresonant 633 nm excitation region. This was found to be lower than 10-29 cm²/sr, much lower than that of a dye molecule commonly used in SERS experiment. We explain the nondetection of TETS by Raman based on a combined intrinsically weak Raman scattering cross section and their low surface concentration, where XPS only shows a surface coverage of less than 0.02 monolayer with respect to the total number of gold sites. Comparing this to our own CD-decorated 10 nm gold nanoparticles (NPs) surface, we found that the inherently greater surface area provided by the NPs increases the amount of CD present (per unit area), giving our surface the capability to detect both the receptor and TETS via attenuated total reflectance (ATR) FTIR. [ABSTRACT FROM AUTHOR]

We present the first report on a large low-temperature magnetoresistance (MR) of more than 1600% in a SrFe2As2 single crystal and 1300% in a low-energy Ca ion-implanted SrFe2As2 single crystal that occurs before the emergence of crystallographic strain-induced bulk superconductivity arising from a sample aging effect. In accordance to band structure calculations from the literature, which consitently show that more than 2 bands are involved in the transport, we have modeled this large MR at high fields using a 3-carrier scenario rather than solely on quantum linear MR model generally used to explain the MR in iron-pnictides. At and below 20 K the large MR may be due to 3-carrier transport in an inhomogeneous state where there are superconducting and metallic regions. [ABSTRACT FROM AUTHOR]

Ferromagnetic order is observed in Gd ion implanted ZnO crystals after annealing at 650 °C in a vacuum and we find that it is intrinsic and extends to depths of up to 40 nm. The ferromagnetic order is not affected by Gd for concentrations as high as 5% and possibly arises from defect clusters. Magnetoresistance is observed at low temperatures that may be due to spin-tunnelling between the defect clusters or spin-dependent scattering at the defect cluster interfaces. Gd implantation has an advantageous effect where it results in mΩ cm resistivities as well as significant electron doping. [ABSTRACT FROM AUTHOR]

The magnetic behavior of titanium dioxide nanobelts has been investigated with and without Co doping. Room temperature ferromagnetism was observed when the Co-doped anatase TiO2 nanobelts were prepared via vacuum annealing of 2.5 at. % Co-doped titanate nanobelts, while annealing them in air resulted in paramagnetic ordering. Interestingly, by vacuum annealing the undoped titanate nanobelts under the same conditions, superparamagnetic ordering was observed in the resulting anatase TiO2 nanobelts. The electron paramagnetic resonance of this latter sample shows a strong symmetrical signal at g=2.003 suggesting some sort of exchange interactions among the localized electrons’ spin moments from single electron trapped in oxygen vacancies. [ABSTRACT FROM AUTHOR]

Conventional wisdom expects that making semiconductors ferromagnetic requires doping with magnetic ions and that superconductivity cannot coexist with magnetism. However, recent concerted efforts exploring new classes of materials have established that intrinsic ferromagnetic semiconductors exist and that certain types of strongly correlated metals can be ferromagnetic and superconducting at the same time. Here we show that the trifecta of semiconducting behavior, ferromagnetism, and superconductivity can be achieved in a single material. Samarium nitride (SmN) is a well-characterized intrinsic ferromagnetic semiconductor, hosting strongly spin-ordered 4f electrons below a Curie temperature of 27 K. We have now observed that it also hosts a superconducting phase below 4 K when doped to electron concentrations above 1021cm-3. The large exchange splitting of the conduction band in SmN favors equal-spin triplet pairing with p-wave symmetry. Significantly, superconductivity is enhanced in superlattices of gadolinium nitride (GdN) and SmN. An analysis of the robustness of such a superconducting phase against disorder leads to the conclusion that the 4f bands are crucial for superconductivity, making SmN a heavy-fermion-type superconductor. [ABSTRACT FROM AUTHOR]

Introduction: High-fidelity simulation (HFS) provides a high level of interactivity and realistic experience for the learner by means of using full scale computerised patient simulators. It imitates clinical experience in a controlled and safe environment that closely resembles reality. The purpose of this study was to compare the efficacy of HFS versus video-assisted lecture (VAL) based education in enhancing and consolidating retention of skills among undergraduate medical students., Materials and Methods: A randomised controlled trial (RCT) study involving 111 undergraduate medical students was conducted where the competency of skills was assessed by objective structured clinical examination (OSCE) in the first, fourth and seventh/eighth weeks. A cohort of 12-14 students was enrolled for each session. The randomisation of the participants into control (VAL-based teaching) and intervention (HFS-based teaching) groups was achieved by implementing the computer-based random sequence generation method. VAL-based teaching module was a fully interactive face-to-face teaching session where a prerecorded video clip was used. The video clip detailed the diagnosis of tension pneumothorax in an acute medical emergency and its management by performing needle decompression on a high-fidelity patient simulator (METIman). HFS-based teaching module was delivered as a fully interactive hands-on training session conducted on the same METIman to demonstrate the diagnosis of tension pneumothorax in an acute medical emergency and its management by performing needle decompression. OSCE scores were compared as the denominator of learning (enhancement and retention of skills) between two groups who underwent training with either VAL-based or HFS-based teachings. The OSCE assessments were used to evaluate the participants' performance as a group. These scores were used to compare the enhancement and medium-term retention of skills between the groups. The outcome was measured with the mean and standard deviation (SD) for the total OSCE scores for skills assessments. We used General Linear Model two-way mixed ANOVA to ascertain the difference of OSCE marks over assessment time points between the control and the intervention groups. ANCOVA and two-way mixed ANOVA were used to calculate the effect size and the partial Eta squared. p value less than 0.05 was taken to be statistically significant., Results: The two-way mixed ANOVA showed no statistically significant difference in mean OSCE scores between intervention and control groups (p=0.890), although the mean score of the intervention group was better than the control group., Conclusion: Our study demonstrated that HFS was not significantly effective over VAL-based education in enhancing skills and consolidating retention among undergraduate medical students. Further research is needed to determine its suitability for inclusion in the course curriculum considering the cost-effectiveness of implementing HFS that may supplement traditional teaching methods.

We report the synthesis, compositional, structural and magnetic properties of permalloy powders prepared using an arc-discharge method under different atmospheres. Ion beam analysis results showed that powder prepared in air had a higher concentration of oxygen than those prepared under nitrogen or argon atmospheres. X-ray diffraction measurements showed that powders prepared in air contained magnetite (Fe3O4) and other phases, while powders prepared under nitrogen or argon predominately contained permalloy. The permalloy powders contained a broad range of particle sizes, and nanoparticles as small as 10 nm were evident from transmission electron microscopy data. The saturation magnetizations were significantly lower for the powders prepared in air than those prepared under nitrogen or argon. This can be attributed to oxidation, where the saturation magnetization is predominately from Fe3O4 for powders made in air. The coercive fields were also significantly larger for powders prepared in air, which is consistent with the powders containing different phases when compared with the permalloy powders. Our results show that permalloy powders can be made in nitrogen and argon, allowing for the production of low oxygen content permalloy powders for device applications. Our results also suggest that the use of an iron anode could result in Fe3O4 powders.