Gas Pickering Emulsion Templated Hollow Carbon for High Rate Performance Lithium Sulfur Batteries

A CO₂ in water nanoparticle stabilized Pickering emulsion is used to template micrometer sized hollow porous nitrogen doped carbon particles for high rate performance lithium sulfur battery. For the first time, nanoparticles serve the dual role of an emulsion stabilizer and a pore template for the shell, directly utilizing in situ generated CO₂ bubbles as template for the core. The minimalistic nature of this method does not require expensive surfactants or additional core templates. Upon polymerization of melamine formaldehyde onto CO₂, a robust polymer/silica composite shell is formed and transformed into a porous shell upon washing. The micrometer‐sized hollow morphology in combination with its nitrogen rich porous shell demonstrates impressive rate capabilities of 670 and 500 mAh g^?1 even at a high rate of 7C and 9C, respectively. This material also possesses excellent cycle durability, exhibiting a low capacity decay of 0.088%/cycle over 300 cycles. Measurement of the shuttle current and impedance provides interesting insight into the polysulfide mass transfer mechanism of hollow structured sulfur hosts.     

TEM characterization of super-hydrophilic Ni-Ti thin film

A super-hydrophilic Ni-Ti thin film is evaluated using cross-sectional transmission electron microscopy (TEM). Following sputter deposition and annealing, the Ni-Ti thin films are chemically treated with buffered oxide etchant, nitric acid and 30% hydrogen peroxide solution to produce a 100-nm-thick surface oxide layer. The fabricated Ni-Ti thin films show a 10- to 15-nm TiO₂ thick layer on its surface with a ~ 67° wetting angle. For the surface treated sample, a porous oxide 100 nm TiO layer is found with a < 5°. It is believed that TiOOH(H₂O)_n complex forms on the surface to produce the observed super-hydrophilic behavior.     

Nanochannel electroporation delivers precise amounts of biomolecules into living cells

Many transfection techniques can deliver biomolecules into cells, but the dose cannot be controlled precisely. Delivering well-defined amounts of materials into cells is important for various biological studies and therapeutic applications. Here, we show that nanochannel electroporation can deliver precise amounts of a variety of transfection agents into living cells. The device consists of two microchannels connected by a nanochannel. The cell to be transfected is positioned in one microchannel using optical tweezers, and the transfection agent is located in the second microchannel. Delivering a voltage pulse between the microchannels produces an intense electric field over a very small area on the cell membrane, allowing a precise amount of transfection agent to be electrophoretically driven through the nanochannel, the cell membrane and into the cell cytoplasm, without affecting cell viability. Dose control is achieved by adjusting the duration and number of pulses. The nanochannel electroporation device is expected to have high-throughput delivery applications.     

Modeling thermal and stress behavior of the fuel–clad interface in monolithic fuel mini-plates

A fuel development and qualification program is in process with the objective of qualifying very high density monolithic low enriched uranium–molybdenum fuel for high-performance research reactors. The monolithic fuel foil creates differences in the mechanical and structural characteristics of the fuel plate because of the planar interface created by the fuel foil and cladding. An initial finite element analysis model has been developed to investigate worst-case scenarios for the basic monolithic fuel plate structure using typical mini-plate irradiation conditions in the Advanced Test Reactor. Initial analysis shows that the stress normal to the fuel–clad interface dominates during irradiation and that the presence of small, rounded delaminations at the interface is not of great concern. However, larger and/or fuel–clad delaminations with sharp corners can create areas of concern, as maximum principal cladding stress, strain, displacement, and peak fuel temperature are all significantly increased. Furthermore, stresses resulting from temperature gradients that cause the plate to bow or buckle in an unconstrained fuel plate configuration is greatly enhanced in a constrained fuel plate configuration. The sensitivities of the model and input parameters are discussed, along with some overlap of initial experimental observations using as-fabricated plate characterization and post-irradiation examination.     

Partial biochemical characterization of tetrazolium red‐reactive Lactobacillus plantarum mutants

One thousand colonies derived from Lactobacillus plantarum ATCC 8014 cells that survived 34–43 × 10³ ergs cm^‐2 ultraviolet irradiation were screened on media containing tetrazolium red to detect fermentative mutants. Fermentation end‐products formed from pyruvate, glucose, or lactose catabolism were determined. All 37 stable tetrazolium red‐reactive mutants had increased pyruvate utilization compared to the wild‐type strain. Only two did not produce lactate from exogenous pyruvate. When glucose or lactose were substrates, these two mutants and six other representative mutants produced lactate at levels similar to the parent strain. Although the average lactate and acetoin production from pyruvate by the mutants and wild‐type strains were similar, 25% of the mutants had increased acetoin production.     

On the sources of methane to the los angeles atmosphere

We use historical and new atmospheric trace gas observations to refine the estimated source of methane (CH(4)) emitted into California's South Coast Air Basin (the larger Los Angeles metropolitan region). Referenced to the California Air Resources Board (CARB) CO emissions inventory, total CH(4) emissions are 0.44 ± 0.15 Tg each year. To investigate the possible contribution of fossil fuel emissions, we use ambient air observations of methane (CH(4)), ethane (C(2)H(6)), and carbon monoxide (CO), together with measured C(2)H(6) to CH(4) enhancement ratios in the Los Angeles natural gas supply. The observed atmospheric C(2)H(6) to CH(4) ratio during the ARCTAS (2008) and CalNex (2010) aircraft campaigns is similar to the ratio of these gases in the natural gas supplied to the basin during both these campaigns. Thus, at the upper limit (assuming that the only major source of atmospheric C(2)H(6) is fugitive emissions from the natural gas infrastructure) these data are consistent with the attribution of most (0.39 ± 0.15 Tg yr(-1)) of the excess CH(4) in the basin to uncombusted losses from the natural gas system (approximately 2.5-6% of natural gas delivered to basin customers). However, there are other sources of C(2)H(6) in the region. In particular, emissions of C(2)H(6) (and CH(4)) from natural gas seeps as well as those associated with petroleum production, both of which are poorly known, will reduce the inferred contribution of the natural gas infrastructure to the total CH(4) emissions, potentially significantly. This study highlights both the value and challenges associated with the use of ethane as a tracer for fugitive emissions from the natural gas production and distribution system.     

Excessive ovarian production of nerve growth factor elicits granulosa cell apoptosis by setting in motion a tumor necrosis factor α/stathmin-mediated death signaling pathway

Excessive nerve growth factor (NGF) production by the ovary, achieved via a transgenic approach, results in arrested antral follicle growth, reduced ovulatory capacity, and a predisposition to cyst formation in response to mildly elevated LH levels. Two salient features in these mutant mice (termed 17NF) are an elevated production of 17α-hydroxyprogesterone (17-OHP(4)), testosterone, and estradiol (E(2)) in response to gonadotropins, and an increased frequency of granulosa cell (GC) apoptosis. In this study, we show that the increase in steroidal response is associated with enhanced expression of Cyp17a1, Hsd17b, and Cyp19a1, which encode the enzymes catalyzing the synthesis of 17-OHP(4), testosterone, and E(2) respectively. Using a proteomic approach, we identified stathmin (STMN1), as a protein that is overproduced in 17NF ovaries. In its phosphorylated state, STMN1 mediates a cell death signal initiated by tumor necrosis factor α (TNF). STMN1 is expressed in GCs and excessive NGF increases its abundance as well as that of its forms phosphorylated at serine (Ser) 16, 25, and 38. TNF synthesis is also increased in 17NF ovaries, and this change is abolished by blocking neurotrophic tyrosine kinase receptors. Inhibiting TNF actions in vivo by administering a soluble TNF receptor prevented the increase in total and phosphorylated STMN1 production, as well as GC apoptosis in NGF-overproducing ovaries. These results indicate that an excess of NGF in the ovary promotes steroidogenesis by enhancing the expression of enzyme genes involved in 17-OHP(4), testosterone, and E(2) synthesis, and causes GC apoptosis by activating a TNF/ STMN1-mediated cell death pathway.     

Effect of TCE concentration and dissolved groundwater solutes on NZVI-promoted TCE dechlorination and H2 evolution

Nanoscale zero-valent iron (NZVI) is used to remediate contaminated groundwater plumes and contaminant source zones. The target contaminant concentration and groundwater solutes (NO3-, Cl-, HCO3-, SO4(2-), and HPO4(2-)) should affect the NZVI longevity and reactivity with target contaminants, but these effects are not well understood. This study evaluates the effect of trichloroethylene (TCE) concentration and common dissolved groundwater solutes on the rates of NZVI-promoted TCE dechlorination and H2 evolution in batch reactors. Both model systems and real groundwater are evaluated. The TCE reaction rate constant was unaffected by TCE concentration for [TCE] < or = 0.46 mM and decreased by less than a factor of 2 for further increases in TCE concentration up to water saturation (8.4 mM). For [TCE] > or = 0.46 mM, acetylene formation increased, and the total amount of H2 evolved at the end of the particle reactive lifetime decreased with increasing [TCE], indicating a higher Fe0 utilization efficiency for TCE dechlorination. Common groundwater anions (5mN) had a minor effect on H2 evolution but inhibited TCE reduction up to 7-fold in increasing order of Cl- < SO4(2-) < HCO3- < HPO4(2). This order is consistent with their affinity to form complexes with iron oxide. Nitrate, a NZVI-reducible groundwater solute, present at 0.2 and 1 mN did not affect the rate of TCE reduction but increased acetylene production and decreased H2 evolution. NO3- present at > 3 mM slowed TCE dechlorination due to surface passivation. NO3- present at 5 mM stopped TCE dechlorination and H2 evolution after 3 days. Dissolved solutes accounted for the observed decrease of NZVI reactivity for TCE dechlorination in natural groundwater when the total organic content was small (< 1 mg/L).     

Treatment of raw poultry with nonthermal dielectric barrier discharge plasma to reduce Campylobacter jejuni and Salmonella enterica

Nonthermal plasma has been shown to be effective in reducing pathogens on the surface of a range of fresh produce products. The research presented here investigated the effectiveness of nonthermal dielectric barrier discharge plasma on Salmonella enterica and Campylobacter jejuni inoculated onto the surface of boneless skinless chicken breast and chicken thigh with skin. Chicken samples were inoculated with antibiotic-resistant strains of S. enterica and C. jejuni at levels of 10(1) to 10(4) CFU and exposed to plasma for a range of time points (0 to 180 s in 15-s intervals). Surviving antibiotic-resistant pathogens were recovered and counted on appropriate agar. In order to determine the effect of plasma on background microflora, noninoculated skinless chicken breast and thighs with skin were exposed to air plasma at ambient pressure. Treatment with plasma resulted in elimination of low levels (10(1) CFU) of both S. enterica and C. jejuni on chicken breasts and C. jejuni from chicken skin, but viable S. enterica cells remained on chicken skin even after 20 s of exposure to plasma. Inoculum levels of 10(2), 10(3), and 10(4) CFU of S. enterica on chicken breast and chicken skin resulted in maximum reduction levels of 1.85, 2.61, and 2.54 log, respectively, on chicken breast and 1.25, 1.08, and 1.31 log, respectively, on chicken skin following 3 min of plasma exposure. Inoculum levels of 10(2), 10(3), and 10(4) CFU of C. jejuni on chicken breast and chicken skin resulted in maximum reduction levels of 1.65, 2.45, and 2.45 log, respectively, on chicken breast and 1.42, 1.87, and 3.11 log, respectively, on chicken skin following 3 min of plasma exposure. Plasma exposure for 30 s reduced background microflora on breast and skin by an average of 0.85 and 0.21 log, respectively. This research demonstrates the feasibility of nonthermal dielectric barrier discharge plasma as an intervention to help reduce foodborne pathogens on the surface of raw poultry.