Ventilation inhomogeneity in patients with cystic fibrosis measured by electrical impedance tomography

Objective: The distribution of ventilation within the lung is inhomogeneous. We hypothesized that the degree of inhomogeneity in patients with cystic fibrosis (CF) differs from that in healthy subjects. Method: Three adult patients with cystic fibrosis (CF) and two healthy subjects were recruited for this preliminary study. Subjects were asked to breathe in as deep and exhale as hard as possible three times. Electrical impedance tomography (EIT) measurements were performed during spirometry tests. The global inhomogeneity index(GI) was applied to assess the degree of ventilation homogeneity at 25%, 50%, 75% and 100% of maximum inspiratory volume. Results: Airway obstruction was detected in CF patients but not in healthy volunteers during spirometry tests. GI decreased as inspiratory volume increased in CF patients (0.59+/-0.20 at 25% and 0.39+/-0.09 at 100%, p<0.01, mean+/-SD) while GI remained unchanged in healthy subjects (0.40+/-0.05 at 25% and 0.37+/-0.03 at 100%, p=0.31). Conclusion: Degree of ventilation homogeneity appears to vary during forced respiration in CF patients, but not in healthy volunteers. EIT is a practical method to measure the inhomogeneity of ventilation distribution

Conditioning a current source using OCCII-GIC for EIT systems

Multi-Frequency EIT has been developed to evaluate the permittivity spectrum of a medium using an improved Howland source. Stray capacitance reduces the output impedance, bandwidth of the data collection leading to erroneous measurements. To address this, we have designed a current source, which uses a novel OCCII - GIC to cancel stray capacitance. The system achieves high output impedance over a 5 MHz frequency range

GREIT is sensitive to training targets near boundary

It has been observed that the distribution of the training targets used to calculate the GREIT reconstruction matrix has a strong impact on its chief figure of merit, the amplitude response (AR). We found that uniform AR requires a minimum target distance to the domain boundary, and target density gradient toward the centre has less impact on uniform AR

Effects of Kevlar® 29 yarn twist on tensile and tribological properties of self-lubricating fabric liner

Yarn twist in textile technology is an important characteristic since it considerably affects the properties of knitted or woven fabrics. Many researchers have investigated the effect of staple-spun yarn twist on the properties of the yarns and fabrics. However, the effects of twist level of Kevlar® 29 filament yarn on the properties of yarn and its resin-impregnated self-lubricating fabric liner are not fully known yet. In this study, we have investigated the effects of Kevlar® 29 twist level on the tensile and tribological properties of the fabric liner (Kevlar® 29/polytetrafluoroethylene fabric-resin composite). Two unexpected findings about the effect of yarn twist have been observed, namely (1) asynchronous twist effect on the yarn’s and the liner’s tensile strength and (2) dissimilar yarn twist effect on the liner’s performance. These findings are mainly attributed to the synergic contributions of the yarn twist and strength and the interaction of the resin with the yarn orientation in the woven fabric structure of the liner

Hyperbaric oxygen therapy as rescue therapy for pediatric frosted branch angiitis with Purtscher-like retinopathy: A case report

IntroductionFrosted branch angiitis (FBA) is an uncommon uveitis characterized by fulminant retinal vasculitis. Purtscher-like retinopathy (PuR) is a rare retinal angiopathy associated with a non-traumatic etiology. Both FBA and PuR can cause profound visual impairments.Case reportWe describe the case of a 10-year-old male who presented with sudden bilateral painless visual loss due to FBA with concurrent PuR, with notable viral prodrome 1 month prior to presentation. Systemic investigations revealed a recent herpes simplex virus 2 infection with a high titer of IgM, positive antinuclear antibody (ANA) (1:640), and abnormal liver function tests. After administration of systemic corticosteroids, anti-viral agents, and subsequent immunosuppressive medications, the FBA was gradually alleviated. However, fundoscopy and optical coherence tomography (OCT) revealed persistent PuR and macular ischemia. Hence, hyperbaric oxygen therapy was administered as a rescue strategy, which resulted in gradual bilateral visual acuity improvement.ConclusionHyperbaric oxygen therapy may be a beneficial rescue treatment for retinal ischemia secondary to FBA with PuR