Poly(vinyl alcohol) / cellulose nanocomposite barrier films

There is a continual interest in developing robust, flexible, durable, lightweight, waterborne polymer barrier coatings which are increasingly resistant towards both chemical warfare agents as well as an ever growing number of toxic industrial chemicals. In this study, barrier films were prepared with poly(vinyl alcohol) (PVOH) and varying amounts of cellulose nanocrystals (CNXLs) as filler. Poly(acrylic acid) (PAA) was used as a crosslinking agent to provide water resistance to PVOH. The films were heat treated at various temperatures (125, 150, 170, 185 °C) in order to determine the optimum crosslinking density. Heat treatment at 170 °C for 45 minutes resulted in films with improved water resistance without polymer degradation. Infrared spectroscopy (FTIR) indicated ester bond formation with heat treatment. Mechanical tests showed that films with 10%CNXLs/ 10%PAA/ 80%PVOH had the highest tensile strength, tensile modulus and toughness of all the films studied. Polarized optical microscopy and atomic force microscopy showed agglomeration of CNXLs at filler loadings of 15% CNXLs. A thermogravimetric analysis (DTGA) showed highly synergistic effects with 10%CNXLs/ 10%PAA/ 80%PVOH and supported the tensile test results. The purpose of these barrier films is to prevent the diffusion of chemical warfare agents while allowing moisture to pass through to allow breathability. Water vapor transmission indicated that all the films allowed moisture to pass. However, moisture diffusion was reduced by the presence of both CNXLs and PAA compared to pure PVOH. The crystalline nature of CNXLs causes the diffusing molecules to undergo a tortuous path, while the crosslinking forms a network structure which reduces diffusion. A standard time lag diffusion test utilizing permeation cups was used to study the chemical barrier properties. The film containing 10%CNXL/ 10%PAA/ 80%PVOH showed an improvement of 90% compared to 100% PVOH film. Surface modification of CNXLs was successful and well dispersed carboxylated CNXLs were obtained. Carboxylated cellulose nanocrystals (C.CNXLs) showed less agglomeration, improved interaction, slightly reduced flux and slightly increased time lags compared to CNXLs

Development of a Modular Real-time Shared-control System for a Smart Wheelchair

In this paper, we propose a modular navigation system that can be mounted on a regular powered wheelchair to assist disabled children and the elderly with autonomous mobility and shared-control features. The lack of independent mobility drastically affects an individual's mental and physical health making them feel less self-reliant, especially children with Cerebral Palsy and limited cognitive skills. To address this problem, we propose a comparatively inexpensive and modular system that uses a stereo camera to perform tasks such as path planning, obstacle avoidance, and collision detection in environments with narrow corridors. We avoid any major changes to the hardware of the wheelchair for an easy installation by replacing wheel encoders with a stereo camera for visual odometry. An open source software package, the Real-Time Appearance Based Mapping package, running on top of the Robot Operating System (ROS) allows us to perform visual SLAM that allows mapping and localizing itself in the environment. The path planning is performed by the move base package provided by ROS, which quickly and efficiently computes the path trajectory for the wheelchair. In this work, we present the design and development of the system along with its significant functionalities. Further, we report experimental results from a Gazebo simulation and real-world scenarios to prove the effectiveness of our proposed system with a compact form factor and a single stereo camera

Perspectives of family members participating in cultural assessment of psychiatric disorders: Findings from the DSM-5 International Field Trial

Despite the important roles families play in the lives of many individuals with mental illness across cultures, there is a dearth of data worldwide on how family members perceive the process of cultural assessment as well as to how to best include them. This study addresses this gap in our knowledge through analysis of data collected across six countries as part of a DSM-5 Field Trial of the Cultural Formulation Interview (CFI). At clinician discretion, individuals who accompanied patients to the clinic visit (i.e. patient companions) at the time the CFI was conducted were invited to participate in the cultural assessment and answer questions about their experience. The specific aims of this paper are (1) to describe patterns of participation of patient companions in the CFI across the six countries, and (2) to examine the comparative feasibility, acceptability, and clinical utility of the CFI from companion perspectives through analysis of both quantitative and qualitative data. Among the 321 patient interviews, only 86 (at four of 12 sites) included companions, all of whom were family members or other relatives. The utility, feasibility and acceptability of the CFI were rated favourably by relatives, supported by qualitative analyses of debriefing interviews. Cross-site differences in frequency of accompaniment merit further study

Development of a Three Dimensional Neural Sensing Device by a Stacking Method

This study reports a new stacking method for assembling a 3-D microprobe array. To date, 3-D array structures have usually been assembled with vertical spacers, snap fasteners and a supporting platform. Such methods have achieved 3-D structures but suffer from complex assembly steps, vertical interconnection for 3-D signal transmission, low structure strength and large implantable opening. By applying the proposed stacking method, the previous techniques could be replaced by 2-D wire bonding. In this way, supporting platforms with slots and vertical spacers were no longer needed. Furthermore, ASIC chips can be substituted for the spacers in the stacked arrays to achieve system integration, design flexibility and volume usage efficiency. To avoid overflow of the adhesive fluid during assembly, an anti-overflow design which made use of capillary action force was applied in the stacking method as well. Moreover, presented stacking procedure consumes only 35 minutes in average for a 4 × 4 3-D microprobe array without requiring other specially made assembly tools. To summarize, the advantages of the proposed stacking method for 3-D array assembly include simplified assembly process, high structure strength, smaller opening area and integration ability with active circuits. This stacking assembly technique allows an alternative method to create 3-D structures from planar components

Revisiting the association between altitude and mortality in dialysis patients.

It was recently reported that residential altitude is inversely associated with all-cause mortality among incident dialysis patients; however, no adjustment was made for key case-mix and laboratory variables. We re-examined this question in a contemporary patient database with comprehensive clinical and laboratory data. In a contemporary 8-year cohort of 144,892 maintenance dialysis patients from a large dialysis organization, we examined the relationship between residential altitude and all-cause mortality. Using data from the US Geological Survey, the average residential altitudes per approximately 43,000 US zip codes were compiled and linked to the residential zip codes of each patient. Mortality risks for these patients were estimated by Cox proportional hazard ratios. The study population's mean ± standard deviation age was 61 ± 15 years. Forty-five percent of patients were women, and 57% of patients had diabetes. In fully adjusted analysis, those residing in the highest altitude strata (≥ 6000 ft) had a lower all-cause mortality risk in fully adjusted analyses: death hazard ratio: 0.92 (95% confidence interval, 0.86-0.99), as compared with patients in the reference group (<250 ft). Residential altitude is inversely associated in all-cause mortality risk in maintenance dialysis patients notwithstanding the unknown and unmeasured confounders

Tackling dementia globally: the Global Dementia Prevention Program (GloDePP) collaboration

Daniel Reidpath - ORCID: 0000-0002-8796-0420 https://orcid.org/0000-0002-8796-0420http://dx.doi.org/10.7189/jogh.09.0201039pubpub

Robust penetrating microelectrodes for neural interfaces realized by titanium micromachining

Neural prosthetic interfaces based upon penetrating microelectrode devices have broadened our understanding of the brain and have shown promise for restoring neurological functions lost to disease, stroke, or injury. However, the eventual viability of such devices for use in the treatment of neurological dysfunction may be ultimately constrained by the intrinsic brittleness of silicon, the material most commonly used for manufacture of penetrating microelectrodes. This brittleness creates predisposition for catastrophic fracture, which may adversely affect the reliability and safety of such devices, due to potential for fragmentation within the brain. Herein, we report the development of titanium-based penetrating microelectrodes that seek to address this potential future limitation. Titanium provides advantage relative to silicon due to its superior fracture toughness, which affords potential for creation of robust devices that are resistant to catastrophic failure. Realization of these devices is enabled by recently developed techniques which provide opportunity for fabrication of high-aspect-ratio micromechanical structures in bulk titanium substrates. Details are presented regarding the design, fabrication, mechanical testing, in vitro functional characterization, and preliminary in vivo testing of devices intended for acute recording in rat auditory cortex and thalamus, both independently and simultaneously