Flexible Microfabricated Parylene Multielectrode Arrays for Retinal Stimulation and Spinal Cord Field Modulation

The first flexible parylene-based multielectrode arrays (MEAs) designed for functional electrical stimulation (FES) in retinal prostheses, and the extension of this technology toward enabling reflex-arc neuromodulation in cases of spinal cord damage or transection, are presented. A single metal layer 16 × 16 retinal electrode array of 125 μm-diameter thin-film Ti/Pt electrodes and lines of 12 μm-pitch has been fabricated as a demonstration of this technology. To allow for even higher density arrays, a novel dual-layer process has also been implemented that enables leads to pass under overlying electrodes without making electrical contact to them. A biomimetic parylene-based electrode array consisting of 1024 electrodes of highly variable spacing, 60 of which have been connected in this manner, has been fabricated according to this paradigm. A parylene-parylene annealing process has also been developed to increase device longevity under accelerated-lifetime saline soak conditions. Surgical tests of novel anatomically-conformal geometries that enable such parylene-based electrode systems to interact with their neuronal targets of interest while causing minimal mechanical damage to tissues or to the implants are also presented. The use of these flexible electrode arrays in spinal cord stimulation experiments in animal models has proven their efficacy in stimulating neurons

Adaptation and validation of Richmond Compulsive Buying Scale in Chinese population

Background and aims Compulsive buying (CB) is a behavioral addiction that is conceptualized as an obsessive–compulsive and impulsive–control disorder. The Richmond Compulsive Buying Scale (RCBS), a six-item self-reporting instrument that has been validated worldwide, was developed based on this theoretical background. This study aimed to adapt RCBS to the Chinese population (RCBS-TC) to guide future national and international prevalence studies. Methods This methodological study was conducted in two phases. Phase 1 involved the forward and backward translation of RCBS, the content and face validation of the RCBS, and the evaluation of its translation adequacy. Phase 2 involved the psychometric testing of RCBS-TC for its internal consistency, stability, and construct validity using confirmatory factor analysis (CFA). Results In Phase 1, RCBS-TC obtained satisfactory item-level (I-CVI = 83.3%–100%) and scale-level content validity index (CVI/AVE = 97.2%), comprehensibility (100%), and translation adequacy [intraclass correlation coefficient (ICC) = 0.858]. In Phase 2, based on data collected from 821 adults, RCBS-TC demonstrated a satisfactory internal consistency (Cronbach’s α = .88; corrected item-total correlation coefficients = 0.61–0.78) 2-week test–retest reliability (ICC = 0.82 based on 61 university students). For construct validation, the CFA results indicated that the corrected first-order two-factor models were acceptable with the same goodness-of-fit indices (χ2/df = 8.56, CFI = 0.99, NFI = 0.98, IFI = 0.99, and RMSEA = 0.09). The 2-week test–retest reliability of RCBS-TC (n = 61) was also satisfactory (ICC = 0.82). Discussion and conclusions This methodological study adopted appropriate and stringent procedures to ensure that the translation and validation of RCBS-TC was of quality. The results indicate that this scale has a satisfactory reliability and validity for the Chinese population

Cost overruns and financial risk in the construction of nuclear power reactors: a critical appraisal

Lovering and colleagues attempt to advance understanding of construction cost escalation risks inherent in building nuclear reactors and power plants, a laudable goal. Although we appreciate their focus on capital cost increases and overruns, we maintain in this critical appraisal that their study conceptualizes cost issues in a limiting way. Methodological choices in treating different cost categories by the authors mean that their conclusions are more narrowly applicable than they describe. We also argue that their study is factually incorrect in its criticism of the previous peer-reviewed literature. Earlier work, for instance, has compared historical construction costs for nuclear reactors with other energy sources, in many countries, and extending over several decades. Lastly, in failing to be transparent about the limitations of their own work, Lovering et al. have recourse to a selective choice of data, unbalanced analysis, and biased interpretation

Separation of rare gases and chiral molecules by selective binding in porous organic cages

The separation of molecules with similar size and shape is an important technological challenge. For example, rare gases can pose either an economic opportunity or an environmental hazard and there is a need to separate these spherical molecules selectively at low concentrations in air. Likewise, chiral molecules are important building blocks for pharmaceuticals, but chiral enantiomers, by definition, have identical size and shape, and their separation can be challenging. Here we show that a porous organic cage molecule has unprecedented performance in the solid state for the separation of rare gases, such as krypton and xenon. The selectivity arises from a precise size match between the rare gas and the organic cage cavity, as predicted by molecular simulations. Breakthrough experiments demonstrate real practical potential for the separation of krypton, xenon and radon from air at concentrations of only a few parts per million. We also demonstrate selective binding of chiral organic molecules such as 1-phenylethanol, suggesting applications in enantioselective separation

Separation of rare gases and chiral molecules by selective binding in porous organic cages

The separation of molecules with similar size and shape is an important technological challenge. For example, rare gases can pose either an economic opportunity or an environmental hazard and there is a need to separate these spherical molecules selectively at low concentrations in air. Likewise, chiral molecules are important building blocks for pharmaceuticals, but chiral enantiomers, by definition, have identical size and shape, and their separation can be challenging. Here we show that a porous organic cage molecule has unprecedented performance in the solid state for the separation of rare gases, such as krypton and xenon. The selectivity arises from a precise size match between the rare gas and the organic cage cavity, as predicted by molecular simulations. Breakthrough experiments demonstrate real practical potential for the separation of krypton, xenon and radon from air at concentrations of only a few parts per million. We also demonstrate selective binding of chiral organic molecules such as 1-phenylethanol, suggesting applications in enantioselective separation