Sandwich Structured Metal oxide/Reduced Graphene Oxide/Metal Oxide-Based Polymer Electrolyte Enables Continuous Inorganic-Organic Interphase for Fast Lithium-Ion Transportation.

Introducing inorganic fillers into organic poly(ethylene oxide)(PEO)-based electrolyte has attracted substantial attention to enhance its ionic conductivity and mechanical strength, but limited inorganic-organic interphases are always caused by isolated particles agglomeration. Herein, a variety of sandwich structured metal oxide/reduced graphene oxide(rGO)/metal oxide nanocomposites to optimize lithium-ion conduction by interconnected amorphous organic-inorganic interphases in lithium metal batteries, are proposed. With the support of high surface area rGO, the agglomeration of metal oxide particles is precluded, forming continuous amorphous organic-inorganic interphases with stacked layer-by-layer structure, thus creating 3D interconnected lithium-ion transportation channels vertically and laterally. Besides, metal oxide nanoparticles with hydroxyls possess high affinity toward bis(tri-fluoromethanesulfonyl)imide anions by hydrogen bindings between hydroxyls and fluorine and metal-oxygen bonds, releasing more free lithium ions. Consequently, PEO-ZnO/rGO/ZnO electrolyte delivers superior ionic conductivity of 1.02 × 10-4 S cm-1 at 25 °C and lithium-ion transference number of 0.38 at 60 °C. Furthermore, ZnO/rGO/ZnO insertion promotes the formation of LiF-rich stable solid electrolyte interface, endowing Li symmetric cells with long-term cycling stability over 900 hours. The corresponding LiFePO4 cathode possesses a high reversible specific capacity of 130 mAh g-1 at 0.5C after cycling 300 cycles with a poor capacity fading of 0.05% per cycle.

A deep learning solution to the marginal stability problems of acoustic feedback systems for hearing aids.

For hearing aids, it is critical to reduce the acoustic coupling between the receiver and microphone to ensure that prescribed gains are below the maximum stable gain, thus preventing acoustic feedback. Methods for doing this include fixed and adaptive feedback cancellation, phase modulation, and gain reduction. However, the behavior of hearing aids in situations where the prescribed gain is only just below the maximum stable gain, called here "marginally stable gain," is not well understood. This paper analyzed marginally stable systems and identified three problems, including increased gain at frequencies with the smallest gain margin, short whistles caused by the limited rate of decay of the output when the input drops, and coloration effects. A deep learning framework, called deep marginal feedback cancellation (DeepMFC), was developed to suppress short whistles, and reduce coloration effects, as well as to limit excess amplification at certain frequencies. To implement DeepMFC, many receiver signals in closed-loop systems and corresponding open-loop systems were simulated, and the receiver signals of the closed-loop and open-loop systems were paired together to obtain parallel signals for training. DeepMFC achieved much better performance than existing feedback control methods using objective and subjective measures.

Brominated flame retardant (BFRs) and Dechlorane Plus (DP) in paired human serum and segmented hair.

Brominated flame retardants (BFRs) and Dechlorane Plus (DP) were measured in both human hair and paired serum samples from a cohort of university students in South China. Segmental analysis was conducted to explore gender difference and the relationships between the hair and serum. The concentrations of total PBDEs in the hair and serum samples were in a range of 0.28-34.1ng/g dry weight (dw) and 0.16-156ng/g lipid weight (lw), respectively. Concentrations of ∑DPs (sum of the syn-DP and anti-DP isomers) in all hair samples ranged from nd-5.45ng/g dry weight. Concentrations of most PBDEs and decabromodiphenylethane (DBDPE) in distal segments (5-10cm from the scalp) were higher than those in the proximal segments (0-5cm from the scalp) (t-test, p < 0.05), which could be due to the longer exposure time of distal segments. The proximal segments exhibited a unique congener profile, more close to that in the serum rather than the distal segments of hair. An obvious gender difference was found in the levels of ∑PBDEs using integrated hair samples, while the difference disappeared when considering alone the proximal segments of hair (0-5cm from scalp) for both genders. This paper provides supplement to the current knowledge on sources of BFRs and DPs in hair and declares the importance of segmental analysis.

Evaluation of deep marginal feedback cancellation for hearing aids using speech and music.

Speech and music both play fundamental roles in daily life. Speech is important for communication while music is important for relaxation and social interaction. Both speech and music have a large dynamic range. This does not pose problems for listeners with normal hearing. However, for hearing-impaired listeners, elevated hearing thresholds may result in low-level portions of sound being inaudible. Hearing aids with frequency-dependent amplification and amplitude compression can partly compensate for this problem. However, the gain required for low-level portions of sound to compensate for the hearing loss can be larger than the maximum stable gain of a hearing aid, leading to acoustic feedback. Feedback control is used to avoid such instability, but this can lead to artifacts, especially when the gain is only just below the maximum stable gain. We previously proposed a deep-learning method called DeepMFC for controlling feedback and reducing artifacts and showed that when the sound source was speech DeepMFC performed much better than traditional approaches. However, its performance using music as the sound source was not assessed and the way in which it led to improved performance for speech was not determined. The present paper reveals how DeepMFC addresses feedback problems and evaluates DeepMFC using speech and music as sound sources with both objective and subjective measures. DeepMFC achieved good performance for both speech and music when it was trained with matched training materials. When combined with an adaptive feedback canceller it provided over 13 dB of additional stable gain for hearing-impaired listeners.

Surface positive-charged modification of inorganic fillers to optimize lithium ion conductive pathways in composite polymer electrolytes for lithium-metal batteries.

The incorporation of inorganic fillers into composite polymer electrolytes (CPEs) is a common strategy to improve ionic conductivity. However, the high surface energy of inorganic fillers typically aggravates poor interfacial contact with polymer chains. Herein, we develop a surface positive-charge modification strategy for enhancing the intermolecular interaction of poly(ethylene oxide) (PEO) electrolytes with inorganic fillers and optimizing lithium ion (Li+) conductive pathways in CPEs. The SiO2 nanoparticles are coated with a polydopamine adhesive layer and then functionalized with a branched polyethyleneimine positively charged functional layer. Such surface modification not only effectively induces more amorphous structure into the PEO matrix but also promotes the dissociation of lithium salts and activates more free Li+ in the PEO to accelerate Li+ transport. The CPEs achieved a superior ionic conductivity of 6.12 × 10-5 S cm-1 at 30 °C. In addition, the modified fillers could induce the formation of a lithium fluoride (LiF)-rich solid-state interphase and correspondingly achieve excellent compatibility with Li metal. The Li symmetric battery using the as-prepared CPEs delivered stable Li plating/stripping performances over 3960 h under 0.2 mA cm-2. The resulting LiFePO4|Li battery has an excellent capacity retention of 92.8 % after 260 cycles at 0.5C and 60 °C.

A proposed prognostic 7-day survival formula for patients with terminal cancer.

BACKGROUND: The ability to identify patients for hospice care results in better end-of-life care. To develop a validated prognostic scale for 7-day survival prediction, a prospective observational cohort study was made of patients with terminal cancer. METHODS: Patient data gathered within 24 hours of hospital admission included demographics, clinical signs and symptoms and their severity, laboratory test results, and subsequent survival data. Of 727 patients enrolled, data from 374 (training group) was used to develop a prognostic tool, with the other 353 serving as the validation group. RESULTS: Five predictors identified by multivariate logistic regression analysis included patient's cognitive status, edema, ECOG performance status, BUN and respiratory rate. A formula of the predictor model based on those five predictors was constructed. When probability was >0.2, death within 7 days was predicted in the training group and validation group, with sensitivity of 80.9% and 71.0%, specificity of 65.9% and 57.7%, positive predictive value of 42.6% and 26.8%, and negative predictive value (NPV) of 91.7% and 90.1%, respectively. CONCLUSION: This predictor model showed a relatively high sensitivity and NPV for predicting 7-day survival among terminal cancer patients, and could increase patient satisfaction by improving end-of-life care.

Short-term variability in levels of urinary phosphate flame retardant metabolites in adults and children from an e-waste recycling site.

In the present study, urine samples (n = 258) were collected from adults (n = 42) and children (n = 22) in an electronic waste (e-waste) recycling site. The concentrations and compositions of six di-esters, or the metabolites of phosphate flame retardants (PFRs), were measured at different time points on consecutive days. Bis(2-chloroethyl) phosphate (BCEP), dibutyl phosphate (DBP), bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), and diphenyl phosphate (DPHP) were detected in more than 50% of urine samples. The median concentrations of BCEP, DBP, BDCIPP, and DPHP were 2.43-4.80, 0.09-2.65, 0.46-0.89, and 0.66-1.83 ng/mL in adult urine samples, respectively. For children, the median concentrations of BCEP, DBP, BDCIPP, and DPHP were 1.23, 0.08, 0.06, and 0.29 ng/mL in morning urine samples, and 1.86, 0.12, 0.14, and 0.27 ng/mL in nightfall urine samples, respectively. Nightfall urine had generally higher levels of di-esters than those in morning urine for both adults and children (p < 0.05). Children had significantly lower concentrations of di-esters than adults, indicating the occupational exposure risks of PFRs for adults. Significant correlations were observed in levels of BDCIPP (3 out of 6 groups of samples) and DPHP (2 out of 6 groups of samples) in couples (p<0.05). Significant correlations between parents and boys were only observed in BCEP levels in nightfall urine samples, and in DBP levels in morning urine samples (p<0.05). The results suggest that di-ester concentrations in e-waste recycling workers are highly variable depending on the time that samples are collected, which could further influence the estimation of human exposure to PFRs.