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Structure–activity relationships built on descriptors of bulk and bulk-terminated surfaces are the basis for the rational design of electrocatalysts. However, electrochemically driven surface transformations complicate the identification of such descriptors. Here we demonstrate how the as-prepared surface composition of (001)-terminated LaNiO 3 epitaxial thin films dictates the surface transformation and the electrocatalytic activity for the oxygen evolution reaction. Specifically, the Ni termination (in the as-prepared state) is considerably more active than the La termination, with overpotential differences of up to 150 mV. A combined electrochemical, spectroscopic and density-functional theory investigation suggests that this activity trend originates from a thermodynamically stable, disordered NiO 2 surface layer that forms during the operation of Ni-terminated surfaces, which is kinetically inaccessible when starting with a La termination. Our work thus demonstrates the tunability of surface transformation pathways by modifying a single atomic layer at the surface and that active surface phases only develop for select as-synthesized surface terminations. Structure–activity relationships built on descriptors of surfaces can help to design electrocatalysts, but their identification for electrochemically driven surface transformations is challenging. The composition of LaNiO 3 thin film surfaces can now dictate surface transformation and activity of the oxygen evolution reaction.

Large experimental programmes in the fields of nuclear and particle physics search for evidence of physics beyond that explained by current theories. The observation of the Higgs boson completed the set of particles predicted by the standard model, which currently provides the best description of fundamental particles and forces. However, this theory’s limitations include a failure to predict fundamental parameters, such as the mass of the Higgs boson, and the inability to account for dark matter and energy, gravity, and the matter–antimatter asymmetry in the Universe, among other phenomena. These limitations have inspired searches for physics beyond the standard model in the post-Higgs era through the direct production of additional particles at high-energy accelerators, which have so far been unsuccessful. Examples include searches for supersymmetric particles, which connect bosons (integer-spin particles) with fermions (half-integer-spin particles), and for leptoquarks, which mix the fundamental quarks with leptons. Alternatively, indirect searches using precise measurements of well predicted standard-model observables allow highly targeted alternative tests for physics beyond the standard model because they can reach mass and energy scales beyond those directly accessible by today’s high-energy accelerators. Such an indirect search aims to determine the weak charge of the proton, which defines the strength of the proton’s interaction with other particles via the well known neutral electroweak force. Because parity symmetry (invariance under the spatial inversion ( x , y , z ) → (− x , − y , − z )) is violated only in the weak interaction, it provides a tool with which to isolate the weak interaction and thus to measure the proton’s weak charge 1 . Here we report the value 0.0719 ± 0.0045, where the uncertainty is one standard deviation, derived from our measured parity-violating asymmetry in the scattering of polarized electrons on protons, which is −226.5 ± 9.3 parts per billion (the uncertainty is one standard deviation). Our value for the proton’s weak charge is in excellent agreement with the standard model 2 and sets multi-teraelectronvolt-scale constraints on any semi-leptonic parity-violating physics not described within the standard model. Our results show that precision parity-violating measurements enable searches for physics beyond the standard model that can compete with direct searches at high-energy accelerators and, together with astronomical observations, can provide fertile approaches to probing higher mass scales. Measurement of the asymmetry in the parity-violating scattering of polarized electrons on protons gives the weak charge of the proton as 0.0719 ± 0.0045, in agreement with the standard model.

The TUCAN (TRIUMF UltraCold Advanced Neutron) Collaboration is completing a new ultracold neutron (UCN) source. The UCN source will deliver UCNs to a neutron electric dipole moment (EDM) experiment. The EDM experiment is projected to be capable of an uncertainty of 1 × 10−27 ecm, competitive with other planned projects, and a factor of ten more precise than the present world’s best. The TUCAN source is based on a UCN production volume of superfluid helium (He-II), held at 1 K, and coupled to a proton-driven spallation target. The production rate in the source is expected to be in excess of 107 UCN/s; since UCN losses can be small in superfluid helium, this should allow us to build up a large number of UCNs. The spallation-driven superfluid helium technology is the principal aspect making the TUCAN project unique. The superfluid production volume was recently cooled, for the first time, and successfully filled with superfluid helium. The design principles of the UCN source are described, along with some of the challenging cryogenic milestones that were recently passed.

Background/Objectives: Replication initiator 1 (Repin1) gene encodes for a zinc-finger protein and has been implicated in the regulation of adipocyte cell size and glucose transport in vitro . Here, we investigate the consequences of reduced adipose tissue (AT) Repin1 expression in vivo . Subjects/Methods: We have inactivated the Repin1 gene in adipose tissue (iARep −/− ) at an age of 4 weeks using tamoxifen-inducible gene targeting strategies on the background of C57BL/6NTac mice. Furthermore, we differentiated human primary adipocytes derived from subcutaneous AT in vitro and knocked down REPIN1 using siRNA technique to measure glycerol release. Results: Conditional Repin1 inactivation results in decreased AT mass, smaller adipocytes in both, subcutaneous and epigonadal AT compared to controls. Compared to controls, iARep −/− mice were more insulin sensitive, had better glucose tolerance and lower LDL-, HDL- and total cholesterol. Significantly lower AT expression of the Repin1 target genes Cd36 and Lcn2 may contribute to the phenotype of iARep −/− mice. Knockdown of REPIN1 in human in vitro differentiated adipocytes revealed an increased glycerol release. Conclusions: In conclusion, deficiency of Repin1 in AT causes alterations in AT morphology and function, which may underlay lower body weight and improved parameters of insulin sensitivity, glucose and lipid metabolism.

We report a precise measurement of the parity-violating asymmetry \\(A_ PV\\) in the elastic scattering of longitudinally polarized electrons from \\(^48 Ca\\). We measure \\(A_ PV =2668 106\\ (stat) 40\\ (syst)\\) parts per billion, leading to an extraction of the neutral weak form factor \\(F_ W (q=0.8733\\) fm\\(^-1) = 0.1304 0.0052 \\ (stat) 0.0020\\ (syst)\\) and the charge minus the weak form factor \\(F_ ch - F_ W = 0.0277 0.0055\\). The resulting neutron skin thickness \\(R_n-R_p=0.121 0.026\\ (exp) 0.024\\ (model)\\)~fm is relatively thin yet consistent with many model calculations. The combined CREX and PREX results will have implications for future energy density functional calculations and on the density dependence of the symmetry energy of nuclear matter.

The search for a dark photon holds considerable interest in the physics community. Such a force carrier would begin to illuminate the dark sector. Many experiments have searched for such a particle, but so far it has proven elusive. In recent years the concept of a low mass dark photon has gained popularity in the physics community. Of particular recent interest is the 8 Be and 4 He anomaly, which could be explained by a new fifth force carrier with a mass of 17 MeV/ c 2 . The proposed Darklight experiment would search for this potential low mass force carrier at ARIEL in the 10-20 MeV/ c 2 e + e − invariant mass range. This proceeding will focus on the experimental design and physics case of the Darklight experiment.

A dimeric hydrogenase enzyme (44.5 and 39.4 kDa sub units) was isolated in a 39.5% yield from the fungus Fusarium oxysporum and purified 4.64-fold by ion exchange chromatography on Sephacryl S-200. Characterisation of the enzyme afforded pH and temperature optima of 7.5 and 38 °C, respectively, a half-life stability of 36 min and a V max and K m of 3.57 nmol min −1  mL −1 and 2.25 mM, respectively. This enzyme was inhibited (non-competitively) by hydrogen hexachloroplatinic acid (H 2 PtCl 6 ) at 1 or 2 mM with a K i value of 118 μM. Incubation of the platinum salt with the pure enzyme under an atmosphere of hydrogen and optimum enzyme conditions (pH 7.5, 38 °C) afforded <10% bioreduction after 8 h while at conditions suitable for platinum nanoparticle formation (pH 9, 65 °C) over 90% reduction took place after the same length of time. Cell-free extract from the fungal isolates produced nearly 90% bioreduction of the platinum salt under both pH and temperature conditions. The bioreduction of the platinum salt by a hydrogenase enzyme takes place by a passive process and not an active one as previously understood.

The Nab experiment will measure the correlation a between the momenta of the beta particle and antineutrino in neutron decay as well as the Fierz term b which distorts the beta spectrum.

Larney and Gericke offer their views to Fabris-Rotelli et al's article \"Development of an early career academic supervisor in Statistics - A discussion towards a guiding rubric.\" Their perspective is that of academic actuaries involved in undergraduate and postgraduate professional training programmes. They commend the authors on a well researched and carefully argued paper, and fully support the renewed attention that has been drawn to the crisis in statistics in South Africa. Actuarial and financial risk management programmes rely heavily on strong teaching capabilities in mathematical statistics. The local crisis in statistics could therefore also be regarded as a crisis for actuarial science and other professional statistics-based programmes, such as the qualifications offered by the Center for Business Mathematics and Informatics (BMI) at the North-West University (NWU). It is true that in South Africa there is increasing pressure on mathematical sciences graduates to enter the workplace rather than pursue further postgraduate studies. However, it is this demand from industry that creates interest and impetus from prospective students. Very few first-year students that enroll for a degree in the mathematical sciences do so with the vision of pursuing a career in academia.

Nanoparticles have a great prospect for therapeutic applications. They can protect drugs under physiological conditions and act as a matrix for directed delivery of drugs, e.g., to a specific tissue or cell type. Polymer-based nanomaterials are considered as highly effective in this regard. Their properties can be tailored to meet specific demands for given therapeutic purposes. Considering the high-quality standards placed on medical products, the question arises: Which type of polymer material should be employed? One might select synthetic polymer compounds, which are highly diverse in terms of the molecular structures and supramolecular architectures that can be created, or biopolymers such as polysaccharides that are renowned for their native biocompatibility.