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Large numbers of high quality graphene transistors were fabricated by chemical vapor deposition and packaged into a standard electronics assembly, enabling the readout of graphene properties on the benchtop. After chemical functionalization, these sensors demonstrate sensitivity into the pM range to inflammation (IL6) and Zika virus (ZIKV NS1) biomarkers. Signal-to-noise ratio (SNR) of graphene biosensors is over an order of magnitude greater than established diagnostic and biophysical assays, namely ELISA and BLI respectively. High precision measurements of protein kinetics captured using this technology, commercially available as the AGILE R100, are comparable to both clinical diagnostic and state-of-the-art biomolecule characterization tools. These results demonstrate that graphene-based platforms are highly attractive biological sensors for next generation diagnostics.
Influenza A (H1N1) pdm09 became the predominant circulating strain in the United States during the 2013–2014 influenza season. Little is known about the epidemiology of severe influenza during this season.
A retrospective cohort study of severely ill patients with influenza infection in intensive care units in 33 US hospitals from September 1, 2013, through April 1, 2014, was conducted to determine risk factors for mortality present on intensive care unit admission and to describe patient characteristics, spectrum of disease, management, and outcomes.
A total of 444 adults and 63 children were admitted to an intensive care unit in a study hospital; 93 adults (20.9%) and 4 children (6.3%) died. By logistic regression analysis, the following factors were significantly associated with mortality among adult patients: older age (>65 years, odds ratio, 3.1 [95% CI, 1.4–6.9], P=.006 and 50–64 years, 2.5 [1.3–4.9], P=.007; reference age 18–49 years), male sex (1.9 [1.1–3.3], P=.031), history of malignant tumor with chemotherapy administered within the prior 6 months (12.1 [3.9–37.0], P<.001), and a higher Sequential Organ Failure Assessment score (for each increase by 1 in score, 1.3 [1.2–1.4], P<.001).
Risk factors for death among US patients with severe influenza during the 2013–2014 season, when influenza A (H1N1) pdm09 was the predominant circulating strain type, shifted in the first postpandemic season in which it predominated toward those of a more typical epidemic influenza season.
Infect. Control Hosp. Epidemiol. 2015;36(11):1251–1260
To investigate an outbreak of New Delhi metallo-β-lactamase (NDM)–producing carbapenem-resistant Enterobacteriaceae (CRE) and determine interventions to interrupt transmission.
Design, Setting, and Patients.
Epidemiologic investigation of an outbreak of NDM-producing CRE among patients at a Colorado acute care hospital.
Case patients had NDM-producing CRE isolated from clinical or rectal surveillance cultures (SCs) collected during the period January 1, 2012, through October 20, 2012. Case patients were identified through microbiology records and 6 rounds of SCs in hospital units where they had resided. CRE isolates were tested by real-time polymerase chain reaction for blaNDM. Medical records were reviewed for epidemiologic links; relatedness of isolates was evaluated by pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). Infection control (IC) was assessed through staff interviews and direct observations.
Two patients were initially identified with NDM-producing CRE during July–August 2012. A third case patient, admitted in May, was identified through microbiology records review. SC identified 5 additional case patients. Patients had resided in 11 different units before identification. All isolates were highly related by PFGE. WGS suggested 3 clusters of CRE. Combining WGS with epidemiology identified 4 units as likely transmission sites. NDM-producing CRE positivity in certain patients was not explained by direct epidemiologic overlap, which suggests that undetected colonized patients were involved in transmission.
A 4-month outbreak of NDM-producing CRE occurred at a single hospital, highlighting the risk for spread of these organisms. Combined WGS and epidemiologic data suggested transmission primarily occurred on 4 units. Timely SC, combined with targeted IC measures, were likely responsible for controlling transmission.
The objective of the present work was to study the differences in the fatty acid (FA) composition of raw sheep milk fat under commercial milk production conditions throughout lactation, in two consecutive years. Particular attention was placed on the C18:2cis-9,trans-11 isomer, C18:1trans-11 acid, and unsaturated FA as the feeding regimen of 10 commercial flocks of latxa dairy sheep changed from indoor feeding to part-time grazing conditions (from early spring) as traditionally practiced in the Basque Country (Northern Spain). Farms located at an altitude of between 600 and 700 m, in two different geographical areas with different rainfall were selected. Milk samples were collected monthly from late January (indoor feeding) until mid-, or end of, June (outdoor feeding), during two consecutive years. In spite of some interannual variability (most likely due to large differences in rainfall), the evolution of individual FA throughout lactation was comparable between years, indicating that it was reproducible under commercial milk production conditions. The average concentrations of C18:2cis-9,trans-11 isomer and C18:1trans-11 acid in milk from the commercial flocks increased about 200% during the transition period (end of March or early April until May), from indoor feeding (late January or early February until the end of March) to the outdoor period (early May to mid-June), remaining constant during the outdoor period (27·53 ± 9·32 μmol/g fat and 71·58 ± 20·53 μmol/g fat, respectively). Non-atherogenic FA comprised approximately 50% of all saturated FA at any time during lactation, whereas the milk atherogenicity index decreased significantly during the outdoor period. The Trolox-equivalent antioxidant capacity of the water-soluble milk fraction did not appear to be influenced by feeding management. The FA composition of cheeses made during the second year with milk from the indoor or outdoor periods reflected those of the corresponding milks. A principal components analysis clearly showed that differences in the milk FA composition were primarily due to outdoor grazing, with very little contribution from the geographical zone or the year.
The species and genera of the family Trogositidae in America north of Mexico are revised. Two subfamilies are recognized: Peltinae and Trogositinae. The Peltinae include: Calitys Thomson (2 species), Eronyxa Reitter (3 species), Ostoma Laicharting (3 species), Grynocharis Thomson (2 species), Lophocateres Olliff (1 species), and Thymalus Latreille (1 species). The Trogositinae include: Nemosoma Latreille (5 species), Cylidrella Sharp (1 species), Corticotomus Sharp (6 species), Euschaefferia Leng (2 species), Airora Reitter (3 species), Temnochila Westwood (10 species), and Tenebroides Piller and Mitterpacher (18 species). Pseudocotomus Schaeffer is placed in synonymy with Euschaefferia Leng and Parafilumis Casey with Corticotomus Sharp. New species are Temnochila omolopha from Arizona and New Mexico and Temnochila rhyssa from California and Idaho. Synonymies, keys, descriptions, collecting and locality data, and illustrations are included. A checklist places all the species and genera in the proposed classification. Interpretation of relationships of the genera and species is included. The North American taxa are associated with the trogositid taxa from other parts of the world, and with groups within the other families of Cleroidea. Relationships among the taxa are postulated. The inclusion of peltines and trogositines in a single family is upheld.
A new model for the provenance, depositional environment and tectonic setting of the Northern Belt of the Southern Uplands is presented. This turbiditic sandstone-dominated sequence was deposited in a sand-rich submarine fan environment, overlying sparse hemipelagic mudstones. The oldest sandstones are rich in juvenile ophiolitic material and record the first clastic input into the Southern Uplands basin. The bulk of the Northern Belt sedimentary sequence, however, is dominated by relatively quartzose sandstones derived from a Proterozoic continental/metamorphic source represented by the Midland Valley terrane of Scotland and Ireland. The quartzose-dominated succession was punctuated by the input of fresh volcanic detritus shed from an oceanic/continental island-arc situated to the W/NW of the Northern Belt basin, with sediment dispersal turning to the NE along the axis of the basin in Scotland. The tectonic setting of the Northern Belt basin remains uncertain. The complex provenance of the sandstones and recognition of major olistostrome units within the Northern Belt succession suggest that it was tectonically active. The onset of clastic deposition within the Southern Uplands terrane broadly corresponds to uplift and erosion of earlier obducted ophiolite in both Scotland and Ireland, possibly in response to collision of Cambrian–early Ordovician island-arc systems with the Laurentian continental margin. If this interpretation is correct, then the possibility arises that the Southern Uplands–Midland Valley terranes record the dismembering of this oceanic/continental island-arc complex within an overall transpressional regime.
Carbon fiber tows have been impregnated by ethanolic solutions of organo-silicon chlorides, and fired at temperatures up to 900°C to form silicon based coatings. Fired tows were subsequently examined by X-ray photoelectron spectroscopy and scanning electron microscopy to characterize the coated material. A uniform silicon oxycarbide is formed at temperatures upwards of 400°C, which provides an oxidation barrier in carbon fiber reinforced metals.
Substituted β-diketonate complexes of barium have limited volatility even at reduced pressures. The addition of nitrogen Lewis bases to the CVD carrier gas allows barium β-diketonates, even those with no reported volatility, to be transported in the vapor phase at temperatures as low as 70°C (atmospheric pressure) with no decomposition. No increase in volatility is observed, however, for barium carboxylate complexes.
Reaction of boehmite, [AI(O)(OH)]n, with an excess of carboxylic acid (HO2CR) results in the formation of the carboxy substituted alumoxanes, [AI(O)x(OH)y(O2CR)z)]n where 2x + y + z = 3 and R = alkyl substituents. The alumoxanes have been fully characterized by SEM, elemental analysis, IR and multinuclear NMR spectroscopy. The physical properties of the alumoxanes are highly dependent on the identity of R, and range from insoluble crystalline powders, e.g. R = CH3, to powders which readily form solutions or gels in hydrocarbon solvents, e.g. R = C5H11. All of the alumoxanes decompose under mild thermolysis to yield γ-alumina.
As a part of the component development process for the particle bed reactor (PBR), it is necessary to develop coatings for fuel particles which will be time and temperature stable. These coatings must not only protect the particle from attack by the hydrogen coolant, but must also help to maintain the bed in a coolable geometry and mitigate against fission product release. In order to develop these advanced coatings, a process to produce chemical vapor reaction (CVR) coatings on fuel for PBRs has been developed.
The initial screening tests for these coatings consisted of testing in flowing hot hydrogen at one atmosphere. Surrogate fuel particles consisting of pyrolytic graphite coated graphite particles have been heated in flowing hydrogen at constant temperature. The carbon loss from these particles was measured as a function of time. Exposure temperatures ranging from 2500 to 3000 K were used and samples were exposed for up to 14 minutes in a cyclical fashion, cooling to room temperature between exposures. The rate of weight loss measured as a function of time is compared to that from other tests of coated materials under similar conditions. Microscopic examination of the coatings before and after exposure was also conducted and these results are presented.
The ternary nitride MgSiN2 crystallizes in a diamond-like structure with a band gap of 4.8 eV. These characteristics make the compound promising for a variety of applications. Recently we succeeded in preparing fully dense ceramics by sintering at 1550°C. Phase composition, chemical properties and the mechanical properties of the as-prepared ceramics are described. The ceramics are resistant to oxidation in air at least up to 920°C. The thermal conductivity at room temperature has been found to be 20 W/m·K. A considerable improvement of the thermal conductivity is expected when improved processing conditions, well within reach, are realized. A reasonable strength of 270 MPa and a fairly good fracture toughness of about 4.3 MPa·m½ are obtained. A hardness of about 15 GPa and a Young's modulus of 235 GPa have been measured. These new ceramics show that it is still possible to find improved materials as compared to the usual oxide and non-oxide ceramics.
As a part of the component development process for the particle bed reactor (PBR), it is necessary to develop coatings which will be time and temperature stable at extremely high temperatures in flowing hydrogen. These coatings must protect the underlying carbon structure from attack by the hydrogen coolant. Degradation which causes small changes in the reactor component, e.g. hole diameter in the hot frit, can have a profound effect on operation. The ability of a component to withstand repeated temperature cycles is also a coating development issue. Coatings which crack or spall under these conditions would be unacceptable. While refractory carbides appear to be the coating material of choice for carbon substrates being used in PBR components, the method of applying these coatings can have a large effect on their performance. Two deposition processes for these refractory carbides, chemical vapor deposition (CVD) and chemical vapor reaction (CVR) have been evaluated.
Screening tests for these coatings consisted of testing of coated 2-D and 3-D weave carbon-carbon in flowing hot hydrogen at one atmosphere. Carbon loss from these samples was measured as a function of time. Exposure temperatures up to 3000 K were used and samples were exposed in a cyclical fashion, cooling to room temperature between exposures. The results of these measurements are presented along with an evaluation of the relative merits of CVR and CVD coatings for this application.
Historically, texture analysis has been useful in explaining processing-induced property anisotropy in metals and deformation history in geological materials. Texture analysis, however, has not been fully utilized in explaining similar phenomena in ceramic systems. The scarcity of texture analysis in ceramic systems could conceivably stem from the classical conception that textures rarely develop in ceramic materials because of their lack of plasticity. While it is true that slip-based textures occur in only a limited number of ceramic systems, textures occur in a multitude of ceramic systems in which dislocation plasticity is not observed. The most prominent non-slip-based texture development mechanism in ceramic systems is grain rotation during processing. Other possible mechanisms for texture development in ceramics are seeded solid solution formation and oriented grain growth. These non-slip-based texture development mechanisms and other phenomena related to the measurement of textures in covalent ceramics are discussed in the context of the A1N-SiC system.
In this study, we employed continuous microscratch testing to determine the effects of interface roughness on adhesion and fracture toughness of thin Ta2N films. These films were sputterdeposited on single crystal sapphire and polycrystal alumina substrates to a thickness of 0.5 μm. Comparison of the results showed that the interfacial fracture energy increased from 0.4 J/m2 for films on the single crystals to 1.5 J/m2 for films on the polycrystals with a corresponding increase in fracture toughness values. These results are consistent with crack deflection and interface roughness models and are useful for understanding adhesion and toughness on the submicron scale. The results also show that the continuous microscratch technique is a viable approach to determining adhesion and toughness of bi-material systems.
B and N K-edge x-ray absorption spectroscopy measurements have been performed on three BN thin films grown on Si substrates using ion-assisted pulsed laser deposition. Comparison of the films’ spectra to those of several single-phase BN powder standards shows that the films consist primarily of sp2 bonds. Other features in the films’ spectra suggest the presence of secondary phases, possibly cubic or rhombohedral BN. Films grown at higher deposition rates and higher ion-beam voltages are found to be more disordered, in agreement with previous work.
The gaseous alkali corrosion kinetics of α-SiC were systematically investigated from 950°C to 1100°C in an atmosphere containing 0.98 vol% sodium nitrate vapors. The reaction of the SiC in the alkali-containing atmosphere follows a linear rate law with an activation energy of 104 kJ/mol. The alkali corrosion is composed of dissolution of SiO2 in the sodium silicate liquid, oxidation of SiC, and adsorption of Na2O from the vapor phase. The overall reaction appears to be controlled by the oxidation at the SiC substrate/sodium silicate liquid interface.