Cutaneous sensory nerve as a substitute for auditory nerve in solving deaf-mutes' hearing problem: an innovation in multi-channel-array skin-hearing technology

The current use of hearing aids and artificial cochleas for deaf-mute individuals depends on their auditory nerve. Skin-hearing technology, a patented system developed by our group, uses a cutaneous sensory nerve to substitute for the auditory nerve to help deaf-mutes to hear sound. This paper introduces a new solution, multi-channel-array skin-hearing technology, to solve the problem of speech discrimination. Based on the filtering principle of hair cells, external voice signals at different frequencies are converted to current signals at corresponding frequencies using electronic multi-channel bandpass filtering technology. Different positions on the skin can be stimulated by the electrode array, allowing the perception and discrimination of external speech signals to be determined by the skin response to the current signals. Through voice frequency analysis, the frequency range of the band-pass filter can also be determined. These findings demonstrate that the sensory nerves in the skin can help to transfer the voice signal and to distinguish the speech signal, suggesting that the skin sensory nerves are good candidates for the replacement of the auditory nerve in addressing deaf-mutes' hearing problems. Scientific hearing experiments can be more safely performed on the skin. Compared with the artificial cochlea, multi-channel-array skin-hearing aids have lower operation risk in use, are cheaper and are more easily popularized.

Deposition of water-soluble inorganic ions in PM_(2.5) in a typical forestry system in Beijing,China

Background: Rapid economic development in China has resulted in an increase in severe air pollution in city groups such as the Beijing-Tianjin-Hebei Metropolitan Region. PM2.5(fine particles with an aerodynamic equivalent diameter of 2.5 [xm or less) is one of the most important pollutants. The deposition process is an important way of removing particles from the air. To evaluate the effect of an urban forest on atmospheric particle removal, a concentration gradient method was used to measure the deposition velocities of water-soluble inorganics in PM2.5 in two national forest parks in Beijing, China. The following eight water-soluble inorganic ions in PM2.5 were investigated: sodium, ammonium, potassium, magnesium, calcium, chloride, nitrate, and sulfate.Methods: Samples were taken from two sites in Beijing from the 7 th to the 15 th May, 2013. The concentrations of water-soluble inorganic ions were analyzed with ion chromatography. We used the concentration gradient technique to estimate the deposition flux and velocity. To determine the relationships between leaf traits and particle accumulation, typical leaf samples from each selected species were studied using scanning electron microscopy.Results: The total deposition flux and total deposition velocity during the daytime were higher than those at night.Sulfate showed the biggest deposition flux and velocity at both study sites, whereas the other ions showed different trends at each site. Result from higher proportion of coniferous to broadleaved trees, the total deposition flux of the eight ions measured in Jiufeng National Forest Park was greater than that in Olympic Forest Park.Conclusions: The deposition velocity was affected by meteorological conditions such as wind speed, temperature,and humidity. The deposition velocity was also influenced by tree species. The surface of plants is an important factor influencing particle deposition. The results of this study may help in assessing the effects of forestry systems on particle removal and provide evidence for urban air pollution control and afforestation of urban areas.

17α-Ethynylestradiol biodegradation in different river-based groundwater recharge modes with reclaimed water and degradation-associated community structure of bacteria and archaea

This study investigated 17α-ethynylestradiol(EE2) biodegradation process and primary metabolic pathways associated with community structures of microorganism during groundwater recharge using reclaimed water. The attenuation rate is 1.58 times higher in wetting and drying alternative recharge(WDAR) than in continual recharge(CR). The primary biotransformation pathways of EE2 in WDAR system began with the oxidation of C-17 on ring D to form a ketone group, and D-ring was subsequently hydroxylated and cleaved. In the CR system, the metabolic pathway changed from the oxidation of C-17 on ring D to hydroxylation of C-4 on ring A, and ring A or B subsequently cleaved; this transition was related to DO, and the microbial community structure. Four hundred fifty four pyrosequencing of 16 s r RNA genes indicated that the bacterial communities in the upper layer of the WDAR system were more diverse than those found in the bottom layer of the CR system; this result was reversed for archaea. Unweighted Uni Frac and taxonomic analyses were conducted to relate the change in bacterial community structure to the metabolic pathway. Microorganism community diversity and structure were related to the concentrations of dissolved oxygen, EE2 and its intermediates in the system. Five known bacterial classes and one known archaeal class, five major bacterial genera and one major archaeal genus might be involved in EE2 degradation. The findings of this study provide an understanding of EE2 biodegradation in groundwater recharge areas under different recharging modes and can facilitate the prediction of the fate of EE2 in underground aquifers.

Arsenic(V)removal from groundwater by GE-HL nanofiltration membrane:effects of arsenic concentration,pH,and co-existing ions

A laboratory-scale investigation was performed to study arsenic(As(V))removal by negatively charged GE-HL nanofiltration(NF)membrane in simulated drinking water.Effects of As(V)concentration(0–200μg·L–1),pH,and co-ions and counter-ions were investigated.The NF membrane presented good stability,and the rejection rates exceeded 90%.The rejection rates of As(V)decreased with the increase of As(V)concentration,while it increased with the increase of pH(reached 96%at pH 6.75).Moreover,a negative relationship was observed between the co-existing ions of Cl^(–),Na^(+),SO_(4)^(2–),and Ca^(2+)and the removal of As(V),in which bivalent ions presented more significant effects than monovalent ions.

Adsorption and biodegradation of three selected endocrine disrupting chemicals in river-based artificial groundwater recharge with reclaimed municipal wastewater

Endocrine disrupting chemical(EDC) pollution in river-based artificial groundwater recharge using reclaimed municipal wastewater poses a potential threat to groundwater-based drinking water supplies in Beijing, China. Lab-scale leaching column experiments simulating recharge were conducted to study the adsorption, biodegradation, and transport characteristics of three selected EDCs: 17β-estradiol(E2), 17α-ethinylestradiol(EE2) and bisphenol A(BPA). The three recharge columns were operated under the conditions of continual sterilization recharge(CSR), continual recharge(CR), and wetting and drying alternative recharge(WDAR). The results showed that the attenuation effect of the EDCs was in the order of WDAR > CR > CSR system and E2 > EE2 > BPA, which followed first-order kinetics. The EDC attenuation rate constants were 0.0783, 0.0505, and 0.0479 m-1 for E2, EE2 and BPA in the CR system, respectively. The removal rates of E2, EE2, and BPA in the CR system were 98%, 96% and 92%, which mainly depended on biodegradation and were affected by water temperature.In the CR system, the concentrations of BPA, EE2, and E2 in soil were 4, 6 and 10 times higher than in the WDAR system, respectively. According to the DGGE fingerprints, the bacterial community in the bottom layer was more diverse than in the upper layer, which was related to the EDC concentrations in the water-soil system. The dominant group was found to be proteobacteria, including Betaproteobacteria and Alphaproteobacteria, suggesting that these microbes might play an important role in EDC degradation.

Emission patterns of biogenic volatile organic compounds from dominant forest species in Beijing, China

Biogenic volatile organic compounds(BVOC s) have significant effects on atmospheric chemistry,ozone formation and secondary organic aerosol formation.Considering few investigations about BOVCs emissions in north China where is facing serious air pollution in recent years,emissions of various BVOCs from 24 dominant forest species in Beijing were measured from June to September in 2018,using a dynamic headspace sampling method.More than one hundred BVOCs in the collected samples were identified by using an automatic thermal desorption-gas chromatography/mass spectrometry,and their emission rates based on leaf biomass were calculated.Isoprene and monoterpenes were verified to be the dominant BVOCs emitted from the tree species,accounting for more than 50% of the total BVOCs.Generally,broad-leaved species displayed high isoprene emission rates,especially the Platanus occidentalis(21.36μg/(g·hr)),Robinia pseudoacacia(11.55μg/(g·hr)),and Lonicera maackii(9.17μg/(g·hr)),while coniferous species emitted high rates of monoterpenes,such as Platycladus orientalis(27.18μg/(g·hr)),Pinus griffithii(23.11μg/(g·hr)),and Pinus armandii(7.42μg/(g·hr)).High emission rates of monoterpenes from the broad-leaved species of Buxus megistophylla(13.07μg/(g·hr)) and Ligustrum uicaryi(5.74μg/(g·hr)),and high isoprene emission rate from the coniferous tree of Taxus cuspidata(5.86μg/(g·hr)) were also observed.The emission rates of sesquiterpenes from each tree were usually 10-100 times smaller than those of isoprene and monoterpenes.Additionally,relatively high emission rates of oxygenated volatile organic compounds and other alkenes than isoprene and monoterpenes were also found for several tree species.

Long-range transport of organic aerosol to Cape Hedo,Japan

An investigation at Cape Hedo, Japan, from 2005 to 2006, focused on the long-range transport of organic aerosol(OA) from the Asian continent. An Aerodyne aerosol mass spectrometer was used to investigate the OA data collected over the study. OA concentrations were low from July to September and peaked during March and April. Based on air mass origins, four OA source regions were identified: northern China,southern China, Japan, and Korea. OA concentrations measured at Cape Hedo from the four sources did not exhibit large differences. Conversely, the frequencies of the air masses reaching Cape Hedo from the different regions varied considerably. Northern China was identified as the primary source of organic aerosols at Cape Hedo. Examination of variations in the ratio of m/z44 to OA concentrations with transport time showed that OAs were partially oxidized during