Phenotypical, genotypical and pathological characterization of the moonwalker mouse, a model of ataxia.

We performed a comprehensive study of the morphological, functional, and genetic features of moonwalker (MWK) mice, a mouse model of spinocerebellar ataxia caused by a gain of function of the TRPC3 channel. These mice show numerous behavioral symptoms including tremor, altered gait, circling behavior, impaired motor coordination, impaired motor learning and decreased limb strength. Cerebellar pathology is characterized by early and almost complete loss of unipolar brush cells as well as slowly progressive, moderate loss of Purkinje cell (PCs). Structural damage also includes loss of synaptic contacts from parallel fibers, swollen ER structures, and degenerating axons. Interestingly, no obvious correlation was observed between PC loss and severity of the symptoms, as the phenotype stabilizes around 2 months of age, while the cerebellar pathology is progressive. This is probably due to the fact that PC function is severely impaired much earlier than the appearance of PC loss. Indeed, PC firing is already impaired in 3 weeks old mice. An interesting feature of the MWK pathology that still remains to be explained consists in a strong lobule selectivity of the PC loss, which is puzzling considering that TRPC is expressed in every PC. Intriguingly, genetic analysis of MWK cerebella shows, among other alterations, changes in the expression of both apoptosis inducing and resistance factors possibly suggesting that damaged PCs initiate specific cellular pathways that protect them from overt cell loss.

Effect of Continuous Glucose Monitoring Device Assistance on Glycemic Control of 2023 Kahramanmaras Doublet Earthquake Survivors with Type 1 Diabetes in Adana, Turkey.

OBJECTIVE: The aim of this study was to investigate the effects of the devastating 2023 Kahramanmaras earthquake on the glycemic control of children with type 1 diabetes (T1DM) in Adana, Turkey. Additionally, the study aimed to assess the impact of continuous glucose monitoring (CGM) device assistance on glycemic control after the earthquake. MATERIALS AND METHODS: A retrospective study was conducted involving 134 children with T1DM receiving intensive insulin treatment. Participants were divided into 2 groups: CGM (+) (n = 58), who benefited from CGM device assistance, and CGM (-) (n = 76), who did not utilize CGM device after the earthquake. Glycated hemoglobin (HbA1c) levels were recorded before and after the earthquake. RESULTS: Following the earthquake, the median HbA1c for all participants changed insignificantly from 8.9% to 8.6% (P = .491). However, in the CGM (+) group, HbA1c levels significantly improved post earthquake (P = .001). Conversely, the CGM (-) group experienced a deterioration in glycemic control (P = .027). A 2-way repeated measures ANOVA revealed a significant interaction effect between CGM device usage and the earthquake on HbA1c levels (F = 17.257, P <.001). Subgroup analysis based on age indicated that the effectiveness of CGM was more pronounced in adolescents (≥12 years) than in younger children (<12 years). CONCLUSION: This study highlights the adverse impact of the earthquake on glycemic control in children with T1DM and underscores the effectiveness of CGM in improving glycemic control, particularly among adolescents. The provision of CGM devices following the earthquake led to enhanced outcomes, mitigating the negative effects of the disaster on glycemic control.

Enhancement of the magnetic anisotropy in single semiconductor nanowires via surface doping and adatom deposition.

The magnetic anisotropy of single semiconductor (ZnO and GaN) nanowires incorporating both a transition metal (Co and Mn, respectively) as a substitutional surface dopant and a heavy metal (Au, Bi, or Pt) adatom is studied by performing density-functional supercell calculations with the HubbardUcorrection. It is found that a substantial enhancement in the magnetic anisotropy energy is obtained through the deposition of Bi; the deposition of Au and Pt leads to significant variation in other magnetic properties, but not in the magnetic anisotropy energy. An analysis within a band description shows that the coexistence of Bi adatom and a surface dopant with large spin moment activates a mechanism involving reorientation and readjustment of the spin moments of electrons in occupied bands in response to the change of magnetization direction, which promotes giant magnetic anisotropy. Our results for adsorption energetics indicate that the accommodation of Bi in the neighborhood of the surface dopant is more likely in GaN nanowires, because the Bi adatom does (not) tend to be closer to the Mn (Co) dopant on the surface of GaN (ZnO) nanowire. The stability of GaN nanowire with giant magnetic anisotropy owing to the incorporation of both Mn and Bi is demonstrated by performingab initiomolecular dynamics simulations at temperatures considerably higher than room temperature. These results suggest that adatom deposition and surface doping can be used complementarily to develop single nanowire-based spintronic devices.

Segregation tendencies of transition-metal dopants in wide band gap semiconductor nanowires.

The segregation tendencies, defect energetics and electrical behavior of transition-metal (Mn and Co) dopants in wide band gap semiconductor (GaN and ZnO) nanowires are investigated by performing density-functional supercell calculations with the Hubbard U correction. Defect calculations and ab initio molecular dynamics simulations are carried out for a comparative exploration of various doping configurations where the dopant resides on interior, subsurface or surface sites. Mn and Co dopants in GaN and ZnO nanowires, respectively, are found to have different segregation tendencies: whereas a uniform distribution of Co dopants throughout ZnO nanowires takes place, indicating no segregation behavior, GaN nanowires can accommodate the majority of Mn dopants in the interior or surface sites, depending on the position of the Fermi level, which indicates not only segregation, but also that the direction of segregation can be reversed by shifting the Fermi level. Due to the latter, the Mn dopants can homogeneously be incorporated into the GaN nanowires only if the Fermi level remains in a certain range. A theoretically justified generalization of the segregation energy is imperative for obtaining these results, which are substantiated by comparison to experimental characterizations. Our findings demonstrate that the segregation tendency of an impurity in a semiconductor nanowire can be tuned by adjusting the position of the Fermi level (as in the case of Mn in GaN nanowires), which is, however, not always possible (as in the case of Co in ZnO nanowires). The analysis of the defect transition energies reveals that substitutional Mn and Co defects in GaN and ZnO nanowires form deep acceptor and deep donor levels, regardless of the doping site. This means that some other means such as codoping, stoichiometry control or gating must be used, if and as required, to shift the Fermi level of Mn-doped GaN or Co-doped ZnO nanowires in order to alter the type of electrical conduction and/or the segregation direction.