Strong, continuous, and highly porous coaxial fibers with cellulose nanofibril (CNF) aerogel core and cellulose-rich sheath were fabricated by wet-spinning hollow fibers and infusing them with aerogel precursor for high-performance thermal insulators. The sheath contained multiscale pores, including microvoids (14.5 μm) and sub-micron pores (133 nm) in bulk, as well as ca. 25–26 nm surface nanopores, to function as a template and protective sheath for the microporous CNF aerogel core. The porous coaxial fibers had many desirable qualities, including low density (0.2 g cm3), high porosity (85%), high specific tensile strength (23.5 ± 2.5 MPa g cm−3), wide working temperatures (−20 to 150 °C), continuous and large-scale producibility, as well as biodegradability. The unique combination of multiscale porous sheath and ultra-low density aerogel core synergistically minimizes heat conductivity by all three mechanisms, i.e., restrain air circulation to limit convective heat transfer, while the poor conducting cellulose permitting little conductive heat transfer and the highly crystalline aerogel cellular walls prohibit infrared radiation, effectively suppresses radiative heat transfer under extreme temperatures.

© 2015, Science Press. All right reserved. Microbial electrolysis cells (MECs) has been recently developed as a new technology for hydrogen production. The organics are degraded by exoelectrogens in anode biofilm and transport electrons directly to anode, while hydrogen is produced by combining electrons and protons on the surface of Pt-catalyzing cathode under a small external voltage between anode and cathode. Municipal waste water was used as the same inoculum to enrich functional communities in 15 single chamber MEC reactors. Various gas production (hydrogen and methane) was maintained over 1 month using glucose as the sole carbon source in phosphate buffer solution (50 mmol·L-1, pH=7.0). The highest hydrogen production rate was up to (3.9±0.6) mol H2/mol glucose with conversion rate of 32.2% for high-H2generation MECs. The highest methane conversion rate was 48.4% in low-H2generation MECs. A 48 h low pH shock was put into anode biofilm and MEC performances were recovered to their functions in 10~15 d. The microbial diversities increased and gas production rates were changed after low pH shock. Hydrogen yield was reduced by 1.8 mol H2/mol glucose in high-H2generation MECs, while the methane yield increased by 0.4 mol CH4/mol glucose. Based on Geochip analysis, cytochrome C genes were mostly enriched in high-H2yield MECs. Thus functional genes were still recovered dominantly after low pH shock and it supported the recovery of electron transport. The carbon degradation genes were substantially changed among anodic communities in most MECs. The functional genes of labile carbon degradation and methane production were significantly changed after microbial community recovery. The carbon degradation gene structure was more significantly changed in high-H2yield MECs than high-methane yield MECs. The methane increase and hydrogen decrease matched well with their stoichiometric relationship.

Using an ultraviolet-light induced fluorescence (UV-LIF) technique, we measured number concentrations of total aerosol particulate matter (tPM) and fluorescent biological aerosol particles (bioPM) (1.0-3.0 µm and 3.0-5.0 µm diameter) in an office and outdoors, sampling with 1-min resolution. The air-conditioning and mechanical ventilation (ACMV) system equipped with high-grade filters was effective in controlling both tPM and bioPM indoors. As expected, removal efficiencies were found to be size dependent. One human subject walking on the carpet was found to be a strong contributor to bioPM, resulting in 2-3 times higher concentration than that outdoors. Compared to the times when the room is vacant, the biological proportion of total airborne particles increased by an order of magnitude during the light walking period. Consequently, indoor-to-outdoor ratios depend on the ACMV operating conditions and on human activities. This pilot study provides preliminary data concerning the bioPM levels in an indoor environment equipped with an ACMV system. Ongoing investigations using this approach promise to improve our understanding of the processes that influence indoor bioaerosol levels and the effectiveness of control alternatives.

Two new two-grid algorithms are proposed for solving the Maxwell eigenvalue problem. The new methods are based on the two-grid methodology recently proposed by Xu and Zhou [Math. Comp., 70 (2001), pp. 17-25] and further developed by Hu and Cheng [Math. Comp., 80 (2011), pp. 1287-1301] for elliptic eigenvalue problems. The new two-grid schemes reduce the solution of the Maxwell eigenvalue problem on a fine grid to one linear indefinite Maxwell equation on the same fine grid and an original eigenvalue problem on a much coarser grid. The new schemes, therefore, save total computational cost. The error estimates reveals that the two-grid methods maintain asymptotically optimal accuracy, and the numerical experiments presented confirm the theoretical results.

Within the rodent visual system, calcitonin gene-related peptide (CGRP) is selectively expressed in neurons in the accessory optic nuclei (AON), including the dorsal terminal nucleus (DTN), lateral terminal nucleus (LTN) and medial terminal nucleus (MTN). To determine whether CGRP-immunoreactive neurons are involved in visual circuitry, electron microscopic preparations were analyzed from normal rats and rats with optic nerve transections. A co-localization analysis was also made because CGRP-labeled neurons had features of GABAergic neurons. Thus, sections were prepared for light microscopy to determine whether CGRP-containing neurons also had glutamate decarboxylase (GAD) and other markers for GABAergic neurons, such as calcium binding proteins: calbindin (CB), calretinin (CR) and parvalbumin (PV). Electron microscopy of the DTN and LTN showed CGRP-labeled somata and dendrites that were postsynaptic to axon terminals forming asymmetric synapses. Many of these axon terminals degenerated following optic nerve transection indicating that retinal ganglion cells form synapses with CGRP-labeled neurons in the AON. In the DTN, LTN and MTN, CGRP-labeled axon terminals formed symmetric synapses with unlabeled somata as well as dendritic shafts and spines. Consistent with this type of synapse being GABAergic were the co-localization data showing that about 90% of the CGRP-labeled neurons co-localized GAD in the AON. Many CGRP-labeled neurons showed immunostaining for CR (40%) whereas only a few had labeling for CB (5%). No CGRP-labeled neurons had PV. These data show that CGRP-containing neurons receive direct retinal input and represent a subpopulation of GABAergic neurons which differentially co-express calcium-binding proteins.

Human activity patterns result in indoor environments playing an important role in exposure outdoor air pollution. In tropical climates, building ventilation conditions and occupant preferences may dramatically affect exposure to particulate matter and ozone, as many buildings rely on natural ventilation for cooling at least some portion of the day. We model exposure to particulate matter (PM) and ozone (O3) in five microenvironments with varying indoor/outdoor PM and O3ratios across three regions of Singapore. Results show that geographic variations in outdoor concentrations of PM and O3contribute to a factor of two difference in daily exposure across age subgroups while differences between more protective and less protective microenvironments result in a factor of three difference in daily exposure.