Improved Through-Plane Thermal Conductivity of Poly(dimethylsiloxane)Composites through the Formation of 3D Filler Foam Using Freeze-Casting and Annealing Processes.

The configuration of a continuous and oriented thermal pathway is essential for efficient heat dissipation in the oriented direction. Three-dimensional (3D) conductive filler structures provide a suitable approach for constructing continuous thermal pathways in polymer-based composites. The aluminum nitride/reduced graphene oxide/poly(dimethylsiloxane) (AlN/rGO/PDMS) composite material is made with a 3D foam structure and focuses on reducing GO and forming foam via polyvinyl alcohol (PVA). We analyze the successful fabrication of hybrid fillers and composites using various methods. The fabricated composite with a 3D network filler foam achieves a through-plane thermal conductivity of 1.43 W/mK and achieves 752% higher thermal conductivity compared to pure PDMS, which is superior to composites without 3D foam. The continuous 3D filler structure via freeze-drying and annealing processes provides efficient thermal dissipation in the through-plane direction pathway, which is critical for enhancing thermal conductivity. Therefore, this work produces a polymer composite material with improved thermal conductivity through various processes.

Interactions between subjective memory complaint and objective cognitive deficit on memory performances.

BACKGROUND: Subjective memory complaint (SMCs) is a common trait amongst older population. The subjective cognition about their memory could depend on objective cognition. The aim of the current study was to examine the interaction between subjective memory cognition (i.e., SMC) and objective cognition on cognitive functions in participants from older generation. METHODS: A total of 219 patients, 181 normal control (NC) patients and 38 patients with mild cognitive impairment (MCI), were examined through standardized and comprehensive clinical evaluation and neuropsychological assessment. The Subjective Memory Complaints Questionnaire was used to assess SMCs along with five cognitive tasks were used to evaluate cognitive decline over following areas: verbal memory, visuospatial memory, attention, fluency, and language. RESULTS: The results of 2 × 2 two-way analysis of variance (ANOVA) showed that there were significant interactions between SMCs and cognitive status (NC, MCI) on memory performances. NC with SMCs showed significantly lower performance in verbal memory and visuospatial memory compared to NCs without SMCs. Conversely, no effect was observed in the MCI group. CONCLUSION: There are interactions between subjective cognition (i.e., SMC) and objective cognition (i.e., cognitive status) on memory performances in older adults. The roles of SMCs on memory performances should be interpreted with older adults' objective cognitive status.

Montreal cognitive assessment reflects cognitive reserve.

BACKGROUND: The Montreal Cognitive Assessment (MoCA) is known to have discriminative power for patients with Mild Cognitive Impairment (MCI). Recently Cognitive Reserve (CR) has been introduced as a factor that compensates cognitive decline. We aimed to assess whether the MoCA reflects CR. Furthermore, we assessed whether there were any differences in the efficacy between the MoCA and the Mini-Mental State Examination (MMSE) in reflecting CR. METHODS: MoCA, MMSE, and the Cognitive Reserve Index questionnaire (CRIq) were administered to 221 healthy participants. Normative data and associated factors of the MoCA were identified. Correlation and regression analyses of the MoCA, MMSE and CRIq scores were performed, and the MoCA score was compared with the MMSE score to evaluate the degree to which the MoCA reflected CR. RESULTS: The MoCA reflected total CRIq score (CRI; B = 0.076, P < 0.001), CRI-Education (B = 0.066, P <  0.001), and CRI-Working activity (B = 0.025, P = 0.042), while MMSE reflected total CRI (B = 0.044, P <  0.001) and CRI-Education (B = 0.049, P <  0.001) only. The MoCA differed from the MMSE in the reflection of total CRI (Z = 2.30). CONCLUSION: In this study, we show that the MoCA score reflects CR more sensitively than the MMSE score. Therefore, we suggest that MoCA can be used to assess CR and early cognitive decline.

Evaluation of stability of interface between CCM (Co-Cr-Mo) UCLA abutment and external hex implant.

PURPOSE: The purpose of this study is to evaluate the stability of interface between Co-Cr-Mo (CCM) UCLA abutment and external hex implant. MATERIALS AND METHODS: Sixteen external hex implant fixtures were assigned to two groups (CCM and Gold group) and were embedded in molds using clear acrylic resin. Screw-retained prostheses were constructed using CCM UCLA abutment and Gold UCLA abutment. The external implant fixture and screw-retained prostheses were connected using abutment screws. After the abutments were tightened to 30 Ncm torque, 5 kg thermocyclic functional loading was applied by chewing simulator. A target of 1.0 × 106 cycles was applied. After cyclic loading, removal torque values were recorded using a driving torque tester, and the interface between implant fixture and abutment was evaluated by scanning electronic microscope (SEM). The means and standard deviations (SD) between the CCM and Gold groups were analyzed with independent t-test at the significance level of 0.05. RESULTS: Fractures of crowns, abutments, abutment screws, and fixtures and loosening of abutment screws were not observed after thermocyclic loading. There were no statistically significant differences at the recorded removal torque values between CCM and Gold groups (P>.05). SEM analysis revealed that remarkable wear patterns were observed at the abutment interface only for Gold UCLA abutments. Those patterns were not observed for other specimens. CONCLUSION: Within the limit of this study, CCM UCLA abutment has no statistically significant difference in the stability of interface with external hex implant, compared with Gold UCLA abutment.

Development and Validation of the Rappel Indicé-24: Behavioral and Brain Morphological Evidence.

The primary goals of the present study were to develop and validate the Rappel Indicé 24 (RI-24), a shorter version of the original Rappel Indicé, which includes 48 items (RI-48), and to identify the specific brain regions that were correlated with scores on the RI-24. Using these clinical scales, the present study evaluated 91 elderly Korean participants who were classified into 3 groups: normal control (NC; n = 34), patients with mild cognitive impairment (MCI; n = 29), and patients with Alzheimer disease (AD; n = 28). Of the 91 participants, 77 also underwent magnetic resonance imaging scans. The RI-24 delayed cued recall (DCR) scores significantly differed among the NC, MCI, and AD groups. A receiver-operating characteristic curve analysis revealed that the RI-24 was very sensitive (89%) and specific (91%) for the detection of AD. Furthermore, although the time needed to administer the RI-24 was half that needed for the RI-48, the 24-item version showed a high correlation (r= .85 for the DCR score) with the 48-item version. In terms of brain morphological characteristics, voxel-based morphometry analyses revealed a significant positive correlation between DCR score and gray matter volume in the parahippocampal gyrus (r= .468), which plays a role in cued recall. Taken together, the present findings indicate that the RI-24 is a sensitive and reliable test for the detection of memory impairments in patients with MCI and AD despite its brief administration time.