Robust Hybrid Flow Analyzer for Formaldehyde

We report fully automated self-calibrating formaldehyde analyzers relying on a hybrid flow format and include operational scheme and design details. Long-term operation is made possible with the use of syringe pumps. Four identical analyzers were built and showed low LODs of 120 pptv or better (S/N = 3) and good linearity over 0–50 ppbv HCHO concentration range (r2 > 0.9960), all concentrations refer to 10 min averaging times. The analyzer can resume normal operation after short-term power failure with at most two cycles of data loss following restart. Good agreement between analyzers was observed for either indoor or outdoor measurements. The use of an integrated HCHO calibration source and full control by the host computer via a graphical user interface program enables the instrument to switch between zero, calibration, and sampling modes in a programmed automated manner. Detailed field data from deployment in three urban Texas locations from the summer of 2006 are presented. Features of the data, including an episode in which the HCHO concentration exceeded 50 ppbv, the highest reported ambient HCHO concentration in North America to our knowledge, are discussed in some detail

Airborne Bacterial Spore Counts by Terbium-enhanced Luminescence Detection: Pitfalls and Real Values

Bacterial spore determination by terbium(III)-dipicolinate luminescence has been reported by several investigators. We collected spore samples with a cyclone and extracted dipicolinic acid (DPA) in-line with hot aqueous dodecylamine, added Tb(III) in a continuous-flow system and detected the Tb(III)-DPA with a gated liquid core waveguide fluorescence detector with a flashlamp excitation source. The absolute limit of detection (LOD) for the system was equivalent to 540 B. subtilis spores (for a 1.8 m3 sample volume (t = 2 h, Q = 15 L/min), concentration LOD is 0.3 spores/L air). Extant literature suggests that, from office to home settings, viable spore concentrations range from 0.1 to 10 spores/L; however, these data have never been validated. Previously reported semiautomated instrumentation had an LOD of 50 spores/L. The present system was tested at five different location settings in Lubbock, Texas. The apparent bacterial spore concentrations ranged from 9 to 700 spores/L and only occasionally exhibited the same trend as the simultaneously monitored total optical particle counts in the ≥0.5 µm size fraction. However, because the apparent spore counts sometimes were very large relative to the 0.5+ µm size particle counts, we investigated potential positive interferences. We show that aromatic acids are very likely large interferents. This interference typically constitutes ∼70% of the signal and can be as high as 95%. It can be completely removed by prewashing the particles

Selective Conversion of Lignin Catalyzed by Palladium Supported on N‑Doped Carbon

Highly selective conversion of lignin is essential to enable high-value utilization of lignin. Herein, we have prepared a palladium supported on N-doped carbon catalyst modified by 1,3,5-trimethylbenzene (TMB). The Pd nanoparticles are better dispersed on the TMB-modified catalyst than on the original catalyst. Therefore, the catalyst modified by TMB is more effective than the original catalyst in selectively converting lignin. When the organosolv lignin is catalyzed by 3 wt % Pd/CBFS-26-TMB (1:2) at 280 °C for 5 h, the yield of phenolic acid is 25.71 wt % and the biochar yield is only 4.5 wt %. Significantly, 52.59% of the phenolic acid monomers are 4-hydroxy-3,5-dimethoxyphenylacetic acid with a yield of 13.52 wt %. Thus, the catalyst 3 wt % Pd/CBFS-26-TMB (1:2) can effectively break the C–C and C–O bonds in the β–O–4 structure to convert lignin into 4-hydroxy-3,5-dimethoxyphenylacetic acid. We have also discussed the possible mechanism of lignin conversion into main products. This provides an essential approach for the high-value utilization of lignin

Robust Hybrid Flow Analyzer for Formaldehyde

We report fully automated self-calibrating formaldehyde analyzers relying on a hybrid flow format and include operational scheme and design details. Long-term operation is made possible with the use of syringe pumps. Four identical analyzers were built and showed low LODs of 120 pptv or better (S/N = 3) and good linearity over 0–50 ppbv HCHO concentration range (r2 > 0.9960), all concentrations refer to 10 min averaging times. The analyzer can resume normal operation after short-term power failure with at most two cycles of data loss following restart. Good agreement between analyzers was observed for either indoor or outdoor measurements. The use of an integrated HCHO calibration source and full control by the host computer via a graphical user interface program enables the instrument to switch between zero, calibration, and sampling modes in a programmed automated manner. Detailed field data from deployment in three urban Texas locations from the summer of 2006 are presented. Features of the data, including an episode in which the HCHO concentration exceeded 50 ppbv, the highest reported ambient HCHO concentration in North America to our knowledge, are discussed in some detail

Stability of Chlorogenic Acid from Artemisiae Scopariae Herba Enhanced by Natural Deep Eutectic Solvents as Green and Biodegradable Extraction Media

A green and inexpensive natural deep eutectic solvent (NADES) was screened and integrated with an ultrasonic technique for extracting chlorogenic acid (CGA) from artemisiae scopariae herba. Response surface methodology was employed to investigate significant factors and optimize their influence. Proline–malic acid exhibited an excellent extraction capacity with a yield of 28.23 mg/g under the optimal conditions of water content of 15% (wt), solid–liquid ratio of 1.0/10 (g/mL), ultrasonic power of 300 W, and extraction time of 25 min. Simultaneously, the stability and antioxidant activity analysis exhibited a better performance of CGA in NADES than that in water and ethanol. The hydrogen-bonding interaction between CGA and natural deep eutectic molecules enhanced the stability and meanwhile protected the antioxidant activity of CGA

Robust Hybrid Flow Analyzer for Formaldehyde

We report fully automated self-calibrating formaldehyde analyzers relying on a hybrid flow format and include operational scheme and design details. Long-term operation is made possible with the use of syringe pumps. Four identical analyzers were built and showed low LODs of 120 pptv or better (S/N = 3) and good linearity over 0–50 ppbv HCHO concentration range (r2 > 0.9960), all concentrations refer to 10 min averaging times. The analyzer can resume normal operation after short-term power failure with at most two cycles of data loss following restart. Good agreement between analyzers was observed for either indoor or outdoor measurements. The use of an integrated HCHO calibration source and full control by the host computer via a graphical user interface program enables the instrument to switch between zero, calibration, and sampling modes in a programmed automated manner. Detailed field data from deployment in three urban Texas locations from the summer of 2006 are presented. Features of the data, including an episode in which the HCHO concentration exceeded 50 ppbv, the highest reported ambient HCHO concentration in North America to our knowledge, are discussed in some detail

Robust Hybrid Flow Analyzer for Formaldehyde

We report fully automated self-calibrating formaldehyde analyzers relying on a hybrid flow format and include operational scheme and design details. Long-term operation is made possible with the use of syringe pumps. Four identical analyzers were built and showed low LODs of 120 pptv or better (S/N = 3) and good linearity over 0–50 ppbv HCHO concentration range (r2 > 0.9960), all concentrations refer to 10 min averaging times. The analyzer can resume normal operation after short-term power failure with at most two cycles of data loss following restart. Good agreement between analyzers was observed for either indoor or outdoor measurements. The use of an integrated HCHO calibration source and full control by the host computer via a graphical user interface program enables the instrument to switch between zero, calibration, and sampling modes in a programmed automated manner. Detailed field data from deployment in three urban Texas locations from the summer of 2006 are presented. Features of the data, including an episode in which the HCHO concentration exceeded 50 ppbv, the highest reported ambient HCHO concentration in North America to our knowledge, are discussed in some detail

Robust Hybrid Flow Analyzer for Formaldehyde

We report fully automated self-calibrating formaldehyde analyzers relying on a hybrid flow format and include operational scheme and design details. Long-term operation is made possible with the use of syringe pumps. Four identical analyzers were built and showed low LODs of 120 pptv or better (S/N = 3) and good linearity over 0–50 ppbv HCHO concentration range (r2 > 0.9960), all concentrations refer to 10 min averaging times. The analyzer can resume normal operation after short-term power failure with at most two cycles of data loss following restart. Good agreement between analyzers was observed for either indoor or outdoor measurements. The use of an integrated HCHO calibration source and full control by the host computer via a graphical user interface program enables the instrument to switch between zero, calibration, and sampling modes in a programmed automated manner. Detailed field data from deployment in three urban Texas locations from the summer of 2006 are presented. Features of the data, including an episode in which the HCHO concentration exceeded 50 ppbv, the highest reported ambient HCHO concentration in North America to our knowledge, are discussed in some detail

Staining showed expression patterns of <i>OsCYP2</i> indicated by the <i>GUS</i> reporter gene which was driven by the promoter of <i>OsCYP2</i>.

A-D: seed, leaf, stem and root of wild type; E-H: seed, leaf, stem and root of the pOsCYP2:GUS transgenic plants.</p

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