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The vast majority of materials shrink in all directions when hydrostatically compressed; exceptions include certain metallic or polymer foam structures, which may exhibit negative linear compressibility (NLC) (that is, they expand in one or more directions under hydrostatic compression). Materials that exhibit this property at the molecular level--crystalline solids with intrinsic NLC--are extremely uncommon. With the use of neutron powder diffraction, we have discovered and characterized both NLC and extremely anisotropic thermal expansion, including negative thermal expansion (NTE) along the NLC axis, in a simple molecular crystal (the deuterated 1:1 compound of methanol and water). Apically linked rhombuses, which are formed by the bridging of hydroxyl-water chains with methyl groups, extend along the axis of NLC/NTE and lead to the observed behavior.

Crystallographic distortions in the alternating aluminium and silicon tetrahedral framework of sodalite (Na 8 Al 6 Si 6 O 24 Cl 2 ), and beryllium and silicon in helvine (Mn 8 Be 6 Si 6 O 24 S 2 ), (framework designated SOD) are described in terms of a set of condensed normal mode amplitudes and phases derived from an ideal tetrahedron of a theoretical aristotype phase. For a sodalite-structured hettotype phase in space group$P{\\overline 4} 3n$, these normal modes transform as the irreducible representations A 1 , E (α) and T 1 (z) of point-group${\\overline 4} 3m$, where to a good approximation A 1 acts as a pure breathing mode, E (α) as a polyhedral distortive mode and T 1 (z) as a rigid unit rotation about the unique${\\overline 4}$axis of the T-site under consideration. Parameterisation of the mode amplitudes in terms of low-order polynomials as a function of thermodynamic variable permits the crystal structure of sodalite-structured phases to be accurately interpolated at intermediate values of the thermodynamic variable. Published data for the high-temperature behaviour of sodalite have been re-analysed in terms of mode amplitudes which accurately reproduce the temperature dependence of the bond lengths, bond angles and the Al–O–Si inter-polyhedral angle. Full expressions for these derived structural parameters in terms of mode amplitudes and the lattice parameter are tabulated and agree with experimental results to within one estimated standard deviation of the experimental parameter. The potential for mode decomposition in lower symmetry SOD framework crystal structures is illustrated by deriving an aristotype structure for tugtupite (Na 8 Al 2 Be 2 Si 8 O 24 Cl 2 ) at room temperature in space group$I{\\overline 4}$.

Biodiversity mitigation is a cornerstone of applied conservation. Mitigation encompasses a suite of practices, ranging from planned avoidance of impacts to creation of new natural habitats. Accurate and appropriate metrics quantifying impacts to natural systems and the effectiveness of restoration are necessary to measure the success of different mitigation strategies. Because effective mitigation requires adequate metrics, we developed a Biodiversity Metrics Framework to assist practitioners and policy makers in assessing biodiversity mitigation metrics. Based on Noss’Hierarchy of Biodiversity, the Scorecard highlights the mismatch between scientifically defined best practices and metrics required by policy. The Framework may serve a vital role in standardizing and validating mitigation projects into the future.

Many neurotransmitter receptors activate G proteins through exchange of GDP for GTP. The intermediate nucleotide-free state has eluded characterization, due largely to its inherent instability. Here we characterize a G protein variant associated with a rare neurological disorder in humans. Gα o K46E has a charge reversal that clashes with the phosphate groups of GDP and GTP. As anticipated, the purified protein binds poorly to guanine nucleotides yet retains wild-type affinity for G protein βγ subunits. In cells with physiological concentrations of nucleotide, Gα o K46E forms a stable complex with receptors and Gβγ, impeding effector activation. Further, we demonstrate that the mutant can be easily purified in complex with dopamine-bound D2 receptors, and use cryo-electron microscopy to determine the structure, including both domains of Gα o , without nucleotide or stabilizing nanobodies. These findings reveal the molecular basis for the first committed step of G protein activation, establish a mechanistic basis for a neurological disorder, provide a simplified strategy to determine receptor-G protein structures, and a method to detect high affinity agonist binding in cells. Many neurotransmitters act on receptors coupled to GTP-binding G proteins. Here authors report the structure and activity of a mutant that locks the nucleotide-free and receptor-bound state of the G protein, leading to a rare neurological disorder.

Spin liquid ground states are predicted to arise within several distinct scenarios in condensed matter physics. The observation of these disordered magnetic states is particularly pervasive among a class of materials known as frustrated magnets, in which the competition between various magnetic exchange interactions prevents the system from adopting long-range magnetic order at low temperatures. Spin liquids continue to be of great interest due to their exotic nature and the possibility that they may support fractionalized excitations, such as Majorana fermions. Systems that allow for such phenomena are not only fascinating from a fundamental perspective but may also be practically significant in future technologies based on quantum computation. Here we show that the underlying antiferromagnetic sublattice in TbInO3 can undergo a crystal field-induced distortion of its buckled triangular arrangement to one based on a honeycomb. The absence of a conventional magnetic ordering transition at the lowest measurable temperatures indicates that another critical mechanism must govern in the ground-state selection of TbInO3. We suggest that anisotropic exchange interactions—mediated through strong spin–orbit coupling on the emergent honeycomb lattice of TbInO3—give rise to a highly frustrated spin liquid.Detailed neutron scattering, magnetic susceptibility and muon spin relaxation studies indicate the absence of long-range magnetic order in the quantum magnet TbInO3 down to 0.46 K— an observation consistent with quantum spin liquid behaviour.

Background Juvenile justice (JJ) youth are at high risk of opioid and other substance use (SU), dysfunctional family/social relationships, and complex trauma. The purpose of the Leveraging Safe Adults (LeSA) Project is to examine the effectiveness of Trust-Based Relational Intervention® (TBRI®; leveraging family systems by providing emotional and instrumental guidance, support, and role modeling) in preventing opioid and other SU among youth after release from secure residential facilities. Methods An effectiveness-implementation Hybrid Type 1 design is used to test the effectiveness of TBRI for preventing non-medical use of opioids among JJ-youth (delayed-start at the site level; a randomized controlled trial at participant level) and to gain insight into facility-level barriers to TBRI implementation as part of JJ re-entry protocols. Recruitment includes two samples (effectiveness: 360 youth/caregiver dyads; implementation: 203 JJ staff) from nine sites in two states over 3 years. Participant eligibility includes 15 to 18-year-olds disposed to community supervision and receiving care in a secure JJ facility, without active suicide risk, and with one caregiver willing to participate. Effectiveness data come from (1) youth and caregiver self-report on background, SU, psychosocial functioning, and youth-caregiver relationships (Months 0, 3, 6, 12, and 18), youth monthly post-release check-ins, and caregiver report on youth psychological/behavioral symptoms, and (2) JJ facility records (e.g., recidivism, treatment utilization). Fidelity assessment includes post-session checklists and measures of TBRI strategy use. Collected four times over four years, implementation data include (1) JJ staff self-report on facility and staff characteristics, use of trauma-informed care and TBRI strategies, and (2) focus groups (line staff, leadership separately) on use of trauma-informed strategies, uptake of new interventions, and penetration, sustainment, and expansion of TBRI practices. Discussion The LeSA study is testing TBRI as a means to empower caregivers to help prevent opioid use and other SU among JJ-youth. TBRI’s multiple components offer an opportunity for caregivers to supplement and extend gains during residential care. If effective and implemented successfully, the LeSA protocol will help expand the application of TBRI with a wider audience and provide guidance for implementing multi-component interventions in complex systems spanning multiple contexts. Trial registration ClinicalTrials.gov NCT04678960 ; registered November 11, 2020; https://clinicaltrials.gov/ct2/show/NCT04678960 .

CaAl 12 O 19 , which can incorporate Ti as both Ti 3+ and Ti 4+ (charge coupled substitution with Mg 2+ ), is one of the first minerals to condense from a gas of solar composition and is used as a ceramic. It is variously known as hibonite, calcium hexaluminate (CaO.6Al 2 O 3 ), and CA 6 . The lattice parameters and unit cell volumes of Ti-substituted hibonite ( P 6 3 / mmc ) with the formulae CaAl 11.8 Ti 3+ 0.2 O 19 and CaAl 9.8 Ti 3+ 0.54 Mg 0.83 Ti 4+ 0.83 O 19 were determined as a function of temperature from ~ 10 to 275 K by neutron powder diffraction. The thermal expansion is highly anisotropic with the expansion in c a factor of ~ 5 greater than that in a . The change in a is approximately equal for the two compounds whereas the change in c is almost 50% larger for CaAl 11.8 Ti 3+ 0.2 O 19 . CaAl 11.8 Ti 3+ 0.2 O 19 also exhibits negative thermal expansion between 10 and 70 K. The change in unit cell volume with temperature of both compositions is well described by a two term Einstein expression. The large change in c is consistent with substitution of Ti onto the M2 and M4 sites of the R-block structural unit.

AIM: Elevational Rapoport's rule, proposed in 1992 by Stevens, predicts that species ranges on mountains become larger in elevational extent with increasing elevation. Here we test this prediction using 160 datasets of range size measured by maximum elevational extents for bats, birds, frogs, non‐volant small mammals, reptiles, and salamanders from mountains around the globe. LOCATION: Mountains distributed globally and spanning 36.5° S to 48.2° N. METHODS: We compare three methods: (1) the Stevens method, which uses the average range size of all species within each elevational band (100‐m bands); (2) the midpoint method, which uses the average range size of species whose midpoints occur in each elevational band; and (3) a quartile method that examines the distribution of only the smallest ranges (less than one‐quarter of the mountain height) to see if their frequency distribution is negatively related to elevation. RESULTS: Support for the elevational Rapoport's rule was weak across all groups of montane vertebrates. For the Stevens method, the mean r² value was 0.32, and strong support (positive relationship, r² value > 0.50) was detected in 40% of the studies, ranging from 20% for salamanders to 57% for frogs. For the midpoint method, the mean r² value was 0.06, and none of the datasets showed strong support. For the quartile method, the mean r² value was 0.26, and strong support (negative relationship, r² value > 0.40) was detected in 38% of the studies, ranging between 10.5% in salamanders and 58% in reptiles. MAIN CONCLUSIONS: Across vertebrates, and within the literature for plants and invertebrates, more empirical studies find a lack of trend than the predicted trend of increasing range size with increasing elevation. Thus, elevational Rapoport's rule is not a consistently predictive pattern for understanding montane patterns in range size.

A universal aristotype crystal structure for leucite/pollucite-structured phases (A 2 B 2 III C 4 IV O 12 , A 2 B II C 5 IV O 12 ) with space group I a 3 ¯ d has been determined by a non-linear optimisation of the fractional coordinates. The resultant T-site tetrahedron exhibits close to perfect 4 ¯ 3 m point group symmetry (quadratic elongation 1.0000124, tetrahedral angle variance 1.53 × 10 −5 degrees 2 ). For any distorted leucite/pollucite crystal structure, an associated aristotype phase can be derived from the optimised fractional coordinates, with the aristotype phase lattice parameter calculated from the volume of the hettotype T-site tetrahedron. Assuming the aristotype T-site tetrahedron to be ideal, the distortion of the hettotype tetrahedron from that of the aristotype is described as the linear sum of the amplitudes of an appropriate set of symmetry-adapted basis-vectors of the effective regular TO 4 molecule consistent with the observed point group symmetry within the crystal structure. The methodology is illustrated by reference to the disordered T-site, leucite-structured phase K 2 MgSi 5 O 12 .