Computerized anatomy of the distal radius and its relevance to volar plating,research, and teaching

Distal radius fractures are common and fracture patterns and fixation can be complex. Computerized anatomy evaluation (CAE) might offer non‐invasive and enhanced anatomy assessment that might help with implant selection and placement and screw length determination. Our goal was to test the accuracy of two CAE methods for anatomical volar plate positioning and screw lengths measurement of the distal radius. We included 56 high‐resolution peripheral quantitative computed tomography scans of intact, human distal radii. Plates were placed manually onto 3D printed models (method 1), which was compared with automated computerized plate placement onto the 3D computer models (method 2). Subsequently, screw lengths were determined digitally for both methods. Screw lengths evaluations were compared via Bland–Altman plots. Both CAE methods resulted in identical volar plate selection and in anatomical plate positioning. For screw length the concordance correlation coefficient was ≥0.91, the location shift ≤0.22 mm, and the scale shift ≤0.16. The differences were smaller than ±1 mm in all samples. Both CAE methods allow for comparable plate positioning and subsequent screw length measurement in distal radius volar plating. Both can be used as a non‐invasive teaching environment for volar plate fixation. Method 2 even offers fully computerized assessments. Future studies could compare our models to other anatomical areas, post‐operative volar plate positioning, and model performance in actual distal radius fracture instead of intact radii. Clin. Anat. 32:361–368, 2019. © 2018 The Authors. Clinical Anatomy published by Wiley Periodicals, Inc. on behalf of American Association of Clinical Anatomists.     

Body-specific influences on performance evaluation in realistic dynamic scenes

According to the body-specificity hypothesis, left-handers (right-handers) are more likely to associate positive attributes with the left (right) side. We tested whether such body-specific influences also apply to evaluative judgments in realistic dynamic scenes. In two experiments (order counterbalanced), N?=?231 participants watched videos from dual mogul competition where two skiers turn downhill through moguls side by side simultaneously and then comparatively rated the skiers’ technical performances. Experiments differed in the required response mode only. In Exp. 1, participants made forced-choice decisions by selecting either the left or right skier as the better performer; in Exp. 2 graded judgments were made on a 10-point scale ranging from ?5 (skier on the left side) to?+?5 (skier on the right side). Body-specific associations were found in Exp. 1 (OR?=?3.16), but not in Exp. 2 (OR?=?1.50). A control experiment (Exp. 3; same participants) revealed that our sample (OR?=?2.31) behaved similar to previously reported samples in a well-established cartoon character task, thereby confirming body-specific associations in our sample on a task with abstract static stimuli. Collectively, body-specific associations seem to apply to realistic dynamic scenes, particularly when frugal forced-choice decisions are required.     

Differential effects of bifrontal tDCS on arousal and sleep duration in insomnia patients and healthy controls

Background

Arousal and sleep represent basic domains of behavior, and alterations are of high clinical importance.

Hippocampal and medial prefrontal cortical volume is associated with overnight declarative memory consolidation independent of specific sleep oscillations

The current study was designed to further clarify the influence of brain morphology, sleep oscillatory activity and age on memory consolidation. Specifically, we hypothesized, that a smaller volume of hippocampus, parahippocampal and medial prefrontal cortex negatively impacts declarative, but not procedural, memory consolidation. Explorative analyses were conducted to demonstrate whether a decrease in slow‐wave activity negatively impacts declarative memory consolidation, and whether these factors mediate age effects on memory consolidation. Thirty‐eight healthy participants underwent an acquisition session in the evening and a retrieval session in the morning after night‐time sleep with polysomnographic monitoring. Declarative memory was assessed with the paired‐associate word list task, while procedural memory was tested using the mirror‐tracing task. All participants underwent high‐resolution magnetic resonance imaging. Participants with smaller hippocampal, parahippocampal and medial prefrontal cortex volumes displayed a reduced overnight declarative, but not procedural memory consolidation. Mediation analyses showed significant age effects on overnight declarative memory consolidation, but no significant mediation effects of brain morphology on this association. Further mediation analyses showed that the effects of age and brain morphology on overnight declarative memory consolidation were not mediated by polysomnographic variables or sleep electroencephalogram spectral power variables. Thus, the results suggest that the association between age, specific brain area volume and overnight memory consolidation is highly relevant, but does not necessarily depend on slow‐wave sleep as previously conceptualized.     

Polyhydroxymethylenes as Multifunctional High Molecular Weight Sugar Alcohols Tailored for 3D Printing and Medical Applications

Common sugar alcohols used as artificial sweeteners and components of polymer networks represent low molecular weight polyhydroxymethylenes (PHMs) with the general formula [CH(OH)]_nH₂ but very low degree of polymerization (n = 2–6). Herein high molecular weight PHM (n >> 100) unparalleled in nature is tailored for 3D printing and medical applications by free radical polymerization of 1,3‐dioxol‐2‐one vinylene carbonate to produce polyvinylene carbonate (PVCA) which yields PHM by hydrolysis. Furthermore, PVCA is solution processable and enables PHM functionalization, membrane formation, and extrusion‐based 3D printing. Opposite to cellulose, amorphous PHM is plasticized by water and is readily functionalized via PVCA aminolysis/hydrolysis to produce polyhydroxymethylene urethane (PHMU), enable PHM crosslinking and coupling of PHM with amine‐functional components like gelatin. After hydrolysis/aminolysis the original PVCA shapes are retained. PVCA solution casting yields PVCA and PHM which exhibits uniform and hierarchic pore architectures. Asymmetric membranes, hydrogels, PHM/collagen blends, and electrospun nonwovens of PVCA, PHM, and PHMU are readily tailored for medical applications. 3D printing of PVCA dispersions containing hydroxyapatite affords porous PVCA, PHMU, and PHM scaffolds useful in regenerative medicine. PHM and functionalized PHMs as carbohydrate‐inspired multifunctional materials indicate in vitro biocompatibility and hold great promise for applications in medicine and health care.     

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