Dataset Information

Improving the High-Frequency Response of PEI-Based Earphone with Sodium Copper Chlorophyllin.

ABSTRACT: The polyetherimide diaphragm, sodium copper chlorophyllin (SCC), and copper ion coating composite used on earphones were observed to improve the high-frequency (10k-14k Hz) performance. This reinforcement phenomenon was expected to make the sound experience brighter and more diverse. By SEM observation, the mixed coating of SCC/Cu2+ on the polyethylenimine (PEI) diaphragm exhibited a planar blocky structure and was tightly bonded to the surface of the PEI polymer without the aid of colloids. The endothermic process of SCC and metal ion complexation was analyzed by isothermal titration calorimetry. The association ratios of SCC/Cu2+ and SCC/Ni2+ were 4/1 and 6/1, respectively, and the SCC/Cu2+ association yielded a stronger binding constant and more free energy. It was expected that the SCC/Cu2+(4/1) mixed liquid would be immobilized on the PEI polymer by multivalent interaction, including hydrogen-bonding networks between carboxyl groups of SCC and amine groups of PEI, and cross-linking of bridging copper ions. We used dimethylethylenediamine (DME) monomer instead of PEI polymer to analyze this multivalent interaction and observed a two-stage exothermic association of SCC/Cu2+(4/1) and DME with a total Gibbs free energy of 15.15 kcal/mol. We observed that the binding energy could be used to explain that the SCC/Cu2+ mixed formulation could be fixed on the surface of the PEI polymer and could enhance the strength of the PEI film. Compared with graphene films, which can continuously improve the performance of high and ultrasonic frequencies, this study was devoted to and was initiated for the purpose of applying porphyrin compounds to improve music performance.

SUBMITTER: Li HZ

PROVIDER: S-EPMC6983146 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature

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Improving the High-Frequency Response of PEI-Based Earphone with Sodium Copper Chlorophyllin.

Li Hao-Zhi HZ Wu Jun-Jie JJ Lee Wei-Jen WJ Chen Chien-Sheng CS

Molecules (Basel, Switzerland) 20200105 1

The polyetherimide diaphragm, sodium copper chlorophyllin (SCC), and copper ion coating composite used on earphones were observed to improve the high-frequency (10k-14k Hz) performance. This reinforcement phenomenon was expected to make the sound experience brighter and more diverse. By SEM observation, the mixed coating of SCC/Cu<sup>2+</sup> on the polyethylenimine (PEI) diaphragm exhibited a planar blocky structure and was tightly bonded to the surface of the PEI polymer without the aid of co ...[more]

PMID: 31948101

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Project description:Bamboo leaf extract solution (BLES) and sodium copper chlorophyllin solution (SCCS) are known for their anti-oxidant activities. Oral malodor is often related with periodontal pathogens. The present study was undertaken to investigate the anti-bacterial effect of both BLES and SCCS on anaerobic periodontal bacteria producing oral malodorous volatile sulfur compounds (VSC).Porphyromonas gingivalis W83 (PG), Prevotella intermidai TDC19B (PI), Fusobacterium nucleatum ATCC25586 (FN) and Prevotella nigrescence ATCC33563 (PN) were investigated as oral isolated bacteria. VSC production ability of the oral strains was investigated by gas chromatography. With serial dilution of BLES or SCCS, the strains PG, PI, FN or PN were cultured anaerobically with AnaeroPack at 37 ℃ for 3 days. For the determination of anti-bacterial action of BLES or SCCS, the inoculum was cultured with original concentrations of BLES 0.16% (w/v) or SCCS 0.25% (w/v).Gas chromatography exhibited that all strains, PG, PI, FN and PN were responsible for producing a high range of H2S and a moderate range of CH3SH. Anti-bacterial effect of BLES or SCCS on the strains was observed. Inhibition of BLES or SCCS on the strains was revealed as concentration dependent. BLES or SCCS inhibited bacterial proliferation at higher concentrations (PG; 0.04% BLES or 0.03% SCCS, PI; 0.002% BLES or 0.03% SCCS, FN; 0.005% BLES or 0.01% SCCS, PN; 0.01% BLES or 0.015% SCCS). No viable bacterial colony observed at original concentration of BLES 0.16% or SCCS 0.25%. Strain growth was eliminated from inhibition at lower concentrations (PG; 0.02% BLES or 0.015% SCCS, PI; 0.001% BLES or 0.015% SCCS, FN; 0.002% BLES or 0.007% SCCS, PN; 0.005% BLES or 0.007% SCCS).High concentrations of both BLES (0.16%) and SCCS (0.25%) show superior inhibiting capability on all four oral malodor associated periodontal anaerobes during testing, suggesting that these compounds might have a beneficial effect on oral health care.

Project description:Thalamic deep brain stimulation (DBS) is an effective treatment for tremor, but the mechanisms of action remain unclear. Previous studies of human thalamic neurons to noted transient rebound bursting activity followed by prolonged inhibition after cessation of high frequency extracellular stimulation, and the present study sought to identify the mechanisms underlying this response. Recordings from 13 thalamic neurons exhibiting low threshold spike (LTS) bursting to brief periods of extracellular stimulation were made during surgeries to implant DBS leads in 6 subjects with Parkinson's disease. The response immediately after cessation of stimulation included a short epoch of burst activity, followed by a prolonged period of silence before a return to LTS bursting. A computational model of a population of thalamocortical relay neurons and presynaptic axons terminating on the neurons was used to identify cellular mechanisms of the observed responses. The model included the actions of neuromodulators through inhibition of a non-pertussis toxin sensitive K(+) current (I(KL)), activation of a pertussis toxin sensitive K(+) current (I(KG)), and a shift in the activation curve of the hyperpolarization-activated cation current (I(h)). The model replicated well the measured responses, and the prolonged inhibition was associated most strongly with changes in I(KG) while modulation of I(KL) or I(h) had minimal effects on post-stimulus inhibition suggesting that neuromodulators released in response to high frequency stimulation are responsible for mediating the post-stimulation bursting and subsequent long duration silence of thalamic neurons. The modeling also indicated that the axons of the model neurons responded robustly to suprathreshold stimulation despite the inhibitory effects on the soma. The findings suggest that during DBS the axons of thalamocortical neurons are activated while the cell bodies are inhibited thus blocking the transmission of pathological signals through the network and replacing them with high frequency regular firing.

Dataset Information

Improving the High-Frequency Response of PEI-Based Earphone with Sodium Copper Chlorophyllin.

Publications

Improving the High-Frequency Response of PEI-Based Earphone with Sodium Copper Chlorophyllin.

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