This is the second paper in a two-part series describing subject and family perspectives from the CENTURY-S (CENtral Thalamic Deep Brain Stimulation for the Treatment of Traumatic Brain InjURY-Safety) first-in-human invasive neurological device trial to achieve cognitive restoration in moderate to severe traumatic brain injury (msTBI). To participate, subjects were independently assessed to formally establish decision-making capacity to provide voluntary informed consent. Here, we report on post-operative interviews conducted after a successful trial of thalamic stimulation. All five msTBI subjects met a pre-selected primary endpoint of at least a 10% improvement in completion time on Trail-Making-Test Part B, a marker of executive function. We describe narrative responses of subjects and family members, refracted against that success. Interviews following surgery and the stimulation trial revealed the challenge of adaptation to improvements in cognitive function and emotional regulation as well as altered (and restored) relationships and family dynamics. These improvements exposed barriers to social reintegration made relevant by recoveries once thought inconceivable. The study’s success sparked concerns about post-trial access to implanted devices, financing of device maintenance, battery replacement, and on-going care. Most subjects and families identified the need for supportive counseling to adapt to the new trajectory of their lives.

In total, 50 healthcare facilities completed a survey in 2021 to characterize changes in infection prevention and control and antibiotic stewardship practices. Notable findings include sustained surveillance for multidrug-resistant organisms but decreased use of human resource-intensive interventions compared to previous surveys in 2013 and 2018 conducted prior to the COVID-19 pandemic.

This is the first article in a two-part series describing subject and family perspectives from the central thalamic deep brain stimulation for the treatment of traumatic brain injury using the Medtronic PC + S first-in-human invasive neurological device trial to achieve cognitive restoration in moderate to severe traumatic brain injury, with subjects who were deemed capable of providing voluntary informed consent. In this article, we report on interviews conducted prior to surgery wherein we asked participants about their experiences recovering from brain injury and their perspectives on study enrollment and participation. We asked how risks and benefits were weighed, what their expectations and fears were, and how decisions were reached about trial participation. We found that informed consent and enrollment decisions are fraught. Subjects and families were often split, with subjects more focused on putative benefits and families concerned about incremental risk. Both subjects and families viewed brain injury as disruptive to personal identity and relationships. As decisions were made about study enrollment, families struggled with recognizing the re-emergent agency of subjects and ceding decision-making authority to subjects who had previously been dependent upon them for protection and guidance. Subjects and family members reported a hope for the relief of cognitive disabilities, improved quality of life, normalization of interpersonal interactions, and a return to work or school as reasons for study participation, along with altruism and a desire to advance science. Despite these aspirations, both subjects and families appreciated the risks of the intervention and did not suffer from a therapeutic misconception. A second essay to be published in the next issue of Cambridge Quarterly of Healthcare Ethics—Clinical Neuroethics will describe interviews conducted after surgery, the effects of cognitive restoration for subjects, families, and challenges presented to the social structures they will call upon to support them through recovery. This subsequent article will be available online prior to its formal publication in October 2023.

We used a survey to characterize contemporary infection prevention and antibiotic stewardship program practices across 64 healthcare facilities, and we compared these findings to those of a similar 2013 survey. Notable findings include decreased frequency of active surveillance for methicillin-resistant Staphylococcus aureus, frequent active surveillance for carbapenem-resistant Enterobacteriaceae, and increased support for antibiotic stewardship programs.

X-ray powder methods have been used to study the room-temperature structures of the synthetic sodalites: Li8(Al6Si6O24)Cl2, K7.6Na0.4(Al6Si6O24)Cl2, and Na8(Al6Si6O24)I2. Natural sodalite was also studied and the atomic coordinates show satisfactory agreement with those determined from the single-crystal data of Löns and Schulz (1967). The LiCl- and KCl- as well as the NaCl-sodalites refined in the expected sodalite space group P3n, but the NaI-sodalite fitted 13m better. The resulting structural data reveal shortcomings in the previous computer models for sodalite structures and an improved computer modelling procedure is devised which successfully predicts atomic coordinates, starting from the experimental a value and an estimate of the cationanion distance. The method incorporates the experimental result that the average T-O distance (T = Al, Si) throughout the samples is ∼ 1.678 Å, and Si-O and Al-O are set at 1.618 and 1.738 Å, respectively. Although T-O remains little changed throughout the samples, the data confirm the inverse relationship between ∠ T-O-T and the tetrahedron tilt angle ϕ, in which ∠ T-O-T approaches ∼ 160° as ϕ → 0° and the sodalite cage becomes fully expanded.

Experiments in the system NaAlSiO4(Ne)−KAlSiO4(Ks)−SiO2(Qz)−H2O at 100 MPa show that the maximum content of NaAlSi2O6 in leucite is ∼4 wt.% and that analcime is close to the stoichiometric composition (NaAlSi2O6.H2O). Analcime forms metastably on quenching the higher-temperature experiments; it is secondary after leucite in experiments quenched from 780°C, while from 850°C it forms by alteration of leucite, and by devitrification of water-saturated glass. Both processes involve reaction with Na-rich aqueous fluids. Stable analcime forms at 500°C, well below the solidus, and cannot form as phenocrysts in shallow volcanic systems. New data for natural analcime macrocrysts in blairmorites are presented for the Crowsnest volcanics, Alberta, Canada. Other researchers have suggested that primary analcime occurs as yellow-brown, glassy, analcime phenocrysts. Our microprobe analyses show that such primary analcime is close to stoichiometric, with very low K2O (<0.1 wt.%), minor Fe2O3 (0.5−0.8 wt.%) and CaO (∼0.5 wt.%). An extrapolation of published experimental data for Ne−Ks−Qz at >500 MPa PH2O, where Anl + melt coexist, suggests that at >800 MPa two invariant points are present: (1) a reaction point involving Kf + Ab + Anl + melt + vapour; and (2) a eutectic with Kf + Anl + Ne + melt + vapour. We suggest that the nepheline-free equilibrium mineral assemblage for Crowsnest samples is controlled by reaction point (1). In contrast, blairmorites from Lupata Gorge, Mozambique, form at eutectic (2), consistent with the presence of nepheline phenocrysts. Our conclusions, based on high- vs. low-pressure experiments, confirm the suggestion made by other authors, that Crowsnest volcanic rocks must have been erupted explosively to preserve glassy analcime phenocrysts during very rapid, upward transport from deep in the crust (H2O pressures ≫500 MPa). Only rare examples survived the deuteric and hydrothermal alteration that occurred during and after eruption.

Djerfisherite [K6(Cu,Fe,Ni)25S26Cl] has been found as a daughter mineral in melt inclusions in melilite from a Kugda melilitolite. The inclusion mineral assemblage includes pyrrhotite, pentlandite, forsterite, diopside, monticellite, phlogopite, wollastonite, nepheline, sodalite, combeite, calcite, Na-K-Ca carbonate, and hydrated calcium silicates. The djerfisherite is Ni-rich rather than Cu-rich consistent with an ultimate upper mantle magma source. The djerfisherite-bearing assemblage formed from primary carbonate/alkali-rich, melilititic melt inclusions which underwent extreme, closed-system, magmatic to postmagmatic fractionation over a temperature range of >1000° to <500 °C.

An inclusion of corundum (ruby) was found in a clinopyroxene xenocryst in alkali basalt from the late-Cenozoic Chanthaburi-Trat volcanics of eastern Thailand. The clinopyroxene is fairly sodic, highly aluminous and magnesian (0.12–0.14 Na, 0.31–0.33 AlIV and 0.36–0.40 AlVI per 6(O), and Mg/(Mg+Fe2+) > 0.9)) and is chemically similar to clinopyroxene inclusions in rubies from nearby alluvial gem deposits, suggesting a common origin for the two types of occurrence. Sapphirine (Mg/(Mg+Fe2+) = 0.91–0.94) and garnet (py56–67alm11–18grs18–23) also occur as inclusions in alluvial rubies. Thermodynamic calculation of the equilibrium 2 di + 2 crn = 2 cats + en constrains the temperatures of clinopyroxene + corundum crystallization to between 800 and 1150 ± 100°C. Use of other equilibria as stability limits places the pressures of crystallization between 10 and 25 kbar, implying depths of between 35 and 88 km. The most Fe-rich clinopyroxene crystallized at a pressure in the lower part of the range. The pyropic garnet inclusions in corundum crystallized at pressures of >18 kbar (i.e. at depths > ~63 km).

The xenocrystic clinopyroxene could have coexisted in equilibrium with garnet of similar composition to the observed inclusions at the deduced temperatures of crystallization. The rubies probably crystallized in rocks of mafic composition, i.e. garnet-clinopyroxenites or garnet-pyriclasites, within the upper mantle.

Sulphosalts in the system CuSbS2-CuBiS2 (chalcostibite-emplectite) form a complete solid solution series. Seven compositions with the general formula Cu(SbxBi1–x)S2 have been synthesized using dry methods at 310°C. All members of the series are orthorhombic (space group Pnma) and show smoothly increasing a and b cell parameters with substitution of Bi for Sb; the c cell parameter increases up to 50% CuBiS2 substitution and then becomes constant. DSC experiments on CuBiS2 show an endothermic heat effect (2.45 kJ/mol.) at 472°C due to the breakdown reaction to Cu3BiS3 (wittichenite) plus Bi2S3 (bismuthinite). With the addition of 10% CuSbS2 to CuBiS2, the decomposition temperature increases and the endothermic peak is broadened but the energy remains essentially the same (2.53 kJ/mol.). No evidence of this decomposition was observed when the amount of the CuSbS2 component was >30%. The local structure and co-ordination of Cu in the samples were studied by EXAFS analysis of the Cu-K edge but no significant variation occurs in the local Cu environment. The Debye-Waller factor for the first shell of S atoms surrounding Cu in end member CuSbS2 tends to be slightly smaller than for the intermediate solid solutions, suggesting that the tetrahedral Cu environments in the intermediate composition samples is somewhat more disordered than in the end-member. The low expansion characteristics along c appear to be controlled by the linkages between the (CuS3 + BiS2) sheets perpendicular to c being relatively inflexible.

The structural relations of solid solutions in the series (Sr1−xBax)Al2O4 were studied using room- and high-temperature X-ray methods, infra-red spectroscopy, and DTA. At room temperature, SrAl2O4 and solid solutions with x up to 0.31 are monoclinic, between x = 0.31 and 0.43 monoclinic and hexagonal forms coexist, and between x = 0.43 and 1.0 only hexagonal forms occur. On heating, a member of the monoclinic series of solid solutions transforms to hexagonal symmetry over a range of temperature within which both monoclinic and hexagonal forms coexist. The proportion of the hexagonal form increases instantaneously as the temperature is raised. The transformation temperature decreases with increasing BaAl2O4 in solid solution and, in addition, the temperature width of the region of coexistence is markedly enlarged. SrAl2O4 transforms over the range 665–705 °C and (Sr0.7Ba0.3)Al2O4 over 170–405 °C. The DTA trace for SrAl2O4 shows a peak at 677 °C. On cooling, the transformations show hysteresis of 15 to 25 °C.

The coexisting monoclinic and hexagonal forms are believed to be isochemical, and discontinuities in cell parameters occur within the region of coexistence both in the compositional series at room temperature and in the elevated temperature transformation experiments. The low-to-high transformation is accompanied by a volume change of −0.2 to −0.3 %, and is believed to be first-order displacive with additional characteristics similar to those of martensitic transformations.

The thermal expansion behaviour of structures in the (Sr,Ba)Al2O4, series indicates that two tilt systems are operative: co-operative rotation of tetrahedra about the c-axis, and tilting of tetrahedra relative to the 0001 plane.

The results for the (Sr,Ba)Al2O4 series are shown to be invaluable in reinterpreting the structural behaviour of members of the nepheline and leucite groups of minerals.

The thermal expansions of trimerite and beryllonite have been determined up to 800°C. No anomalies were observed in the thermal expansion curves but the expansion coefficients for beryllonite are approximately twice those of trimerite. The thermal expansion behaviour of the minerals is interpreted in terms of a tetrahedral tilting model with the main change in apparent tilting being about the monoclinic 010 plane, i.e. the 0001 pseudo-hexagonal plane.

Discontinuities occurring in the expansion behaviour of aluminosilicate-sodalites with large cavity anions such as I− and are thought to occur when the coordinate of the cavity cation becomes 0.25 (Henderson and Taylor, 1978). We also suggested that further thermal expansion work could explore how the disposition of sodalites in a diagram such as fig. 4 of Henderson and Taylor relates to the presence or absence of discontinuities.

We have now studied the expansion of three more sodalites which were expected to show discontinuities, namely one aluminogermanate-sodalite (Na8(Al6Ge6O24)I2) and two aluminate-sodalites (Sr8(Al12O24)(CrO4)2 and Sr2Ba6(Al12 O24)(SO4)2). Sr8(Al12O24)(CrO4)2 was thought to have an ∼ 9 Å cubic cell at room temperature but the occurrence of broadened and split reflections in our sample suggests that this is not the case. Stepwise heating experiments on our sample showed the presence of a reversible, presumably displacive, transformation at 40±2 °C above which the X-ray reflections were sharp.

All three sodalites showed significantly smaller expansion rates than for aluminosilicate-sodalites having similar degrees of structural collapse. The lower mean expansion coefficient (0–500 °C) for Na8(Al6Ge6O24)I2 of 12.5 × 10−6C−1 compared with that for Na8(Al6Si6O24)I2 of 15.1 × 10−6C−1 is particularly significant as the only chemical difference between these two phases is substitution of Ge for Si. In addition none of the three sodalites showed the discontinuities expected and this suggests that the low expansion rates do not allow the cavity cation to reach a coordinate of 0.25 over the temperature range investigated.

Our earlier concept of the mechanism of expansion of the sodalite structure assumed that the expansion of the cavity cation-cavity anion bond forced the cavity cations against and between the framework oxygens so untwisting the partially collapsed structure (Henderson and Taylor, 1978). It now appears that this concept was over-simplified and that the expansion characteristics of sodalites depend on the nature of the tetrahedrally coordinated framework cations present as well as on the cavity cations and anions.