The hydroxycinnamic acid content of barley and brewers’ spent grain (BSG) and the potential to incorporate phenolic extracts of BSG as antioxidants into fruit beverages

The hydroxycinnamic acid (HA) content of starting barley for brewers’ spent grains (BSG), whole BSG and phenolic extracts from BSG was measured using high performance liquid chromatography (HPLC) and correlated with antioxidant potential. The effect of BSG phenolic extracts on antioxidant activity of fruit beverages was also assessed (using the total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays). The concentration of HA present in barley extract and BSG was in the order of ferulic acid (FA), p-coumaric acid (p-CA) derivatives, FA derivatives, p-CA, caffeic acid (CA) and CA derivatives. Results suggested that brewing and roasting decreased the HA content. Antioxidant activity was significantly (P < 0.05) correlated with caffeic acid (R² = 0.8309) and total HA (R² = 0.3942) concentrations. Addition of extracts to fruit beverages resulted in a significant (P < 0.05) increase in antioxidant activity of cranberry juice, measured by the FRAP assay. In vitro digestion significantly (P < 0.05) reduced TPC, DPPH and FRAP activity of the fruit beverages.     

Optical Control of Transcription: Genetically Encoded Photoswitchable Variants of T7 RNA Polymerase

Light-sensing protein domains that link an exogenous light signal to the activity of an enzyme have attracted much attention for the engineering of new regulatory mechanisms into proteins and for studying the dynamic behavior of intracellular reactions and reaction cascades. Light–oxygen–voltage (LOV) photoreceptors are blue-light-sensing modules that have been intensely characterized for this purpose and linked to several proteins of interest. For the successful application of these tools, it is crucial to identify appropriate fusion strategies for combining sensor and enzyme domains that sustain activity and light-induced responsivity. Terminal fusion of LOV domains is the natural strategy; however, this is not transferrable to T7 RNA polymerase because both of its termini are involved in catalysis. It is shown herein that it is possible to covalently insert LOV domains into the polymerase protein, while preserving its activity and generating new light-responsive allosteric coupling.     

Continuous Process for the Production of Hexafluoroisopropanol

There has been a renewed interest in the design of catalytic reactors to reduce transport limitations. Towards this goal, a novel single fluid-phase recirculating packed bed reactor concept has been developed and demonstrated for the hydrogenation of hexafluoroacetone to hexafluoroisopropanol, a precursor to Sevoflurane, used as an inhalation anesthetic, in the presence of a Ni/Al₂O₃ catalyst.

     

Continuous Process for the Production of Hexafluoroisopropanol

There has been a renewed interest in the design of catalytic reactors to reduce transport limitations. Towards this goal, a novel single fluid-phase recirculating packed bed reactor concept has been developed and demonstrated for the hydrogenation of hexafluoroacetone to hexafluoroisopropanol, a precursor to Sevoflurane, used as an inhalation anesthetic, in the presence of a Ni/Al₂O₃ catalyst.     

Electron Donation–Backdonation and the Rules of Catalytic Promotion

The rules of classical and electrochemical promotion of catalysis, which allow for the prediction of the effect of electropositive and electronegative promoters on catalytic rate and selectivity on the basis of the catalytic reaction kinetics, are compared with experiment for all relevant catalytic studies during the last two decades and are used to show that the rate versus catalyst work function dependence always parallels the rate versus electron donor reactant dependence. This generalized rule is rationalized both by considering the interaction of the electric field in the effective double layer at the metal catalyst–gas interface with the electric dipoles of the adsorbed reactants and also by considering the electron donation–backdonation between the adsorbed reactants and the catalyst. This generalized promotional rule allows for promoter selection on the basis of the reaction kinetics.     

A MALDI MS Investigation of the Lysophosphatidylcholine/Phosphatidylcholine Ratio in Human Spermatozoa and Erythrocytes as a Useful Fertility Marker

The human spermatozoa membrane is characterized by a unique fatty acyl composition with significant amounts of highly unsaturated fatty acids, particularly docosahexaenoic acid (22:6), whereby phosphatidylcholine (PtdCho) (16:0/22:6) is the most abundant glycerophospholipid. The large amount of highly unsaturated fatty acyl residues is crucial for the fluidity of the membrane and, therefore, the successful fertilization process. Consequently, however, the spermatozoa are very sensitive to reactive oxygen species (ROS) that are generated under conditions of “oxidative stress” and key players in many pathological conditions. Lipid oxidation of the sperm membrane is accompanied by the loss of the oxidatively modified unsaturated residue (normally in the sn-2 position) and the generation of saturated lysophosphatidylcholine (LysoPtdCho). Although other lysolipids are also generated, LysoPtdCho is the “marker” lipid of choice due to the high abundance of PtdCho. In particular, obesity (body mass index >30 kg/m²) is characterized by increased ROS generation and negatively affects the reproductive potential. We will show here that the LysoPtdCho/PtdCho ratio can be easily determined by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). The data found do correlate with clinical markers of sperm quality. A very interesting aspect is that the LysoPtdCho/PtdCho ratios determined in the spermatozoa extracts correlate with the LysoPtdCho/PtdCho values determined in the organic extracts of erythrocytes. Thus, there is no absolute need for a sperm investigation, but an estimation of the fertilizing ability of the corresponding male could be also made directly from the blood which is more readily available than the spermatozoa.     

A Laminar-Flow,Water-Based Condensation Particle Counter (WCPC)

A new water-based condensation particle counter (WCPC) is presented. The WCPC is a thermally diffusive, laminar flow instrument. Condensational enlargement is achieved through the introduction of a saturated airflow into a “growth tube” with wetted walls held at a temperature higher than that of the entering flow. An unsheathed, 1 L/min instrument utilizing this principle has been evaluated with various aerosols. The particle size detected with an efficiency of 50% is at or below 4.8 nm for particles sampled from vehicular emissions or ambient air, and for various laboratory-generated inorganic salts. The cut point is higher for the organic materials tested, ranging from 8 nm to 30 nm depending on the compound and purity level. An empirically determined dead-time correction factor is applied to the coincidence correction, which allows extension of the single-count mode to higher concentrations. The counting efficiencies for 80 nm oil and salt aerosols are equal, and above 97% for concentrations approaching 10 ⁵ cm ^?3 . When subject to a step-fucntion change in input concentration the time required to attain 90% of the final value, including a 0.5 s lag, is 1.3 s. The corresponding exponential time constant is 0.35 s. The WCPC evaluated here is marketed as the TSI Model 3785.     

Performance Evaluation and Use of a Continuous Monitor for Measuring Size-Fractionated PM 2.5 Nitrate

A field evaluation of a new size-fractionating continuous fine particle nitrate monitor from Aerosol Dynamics Inc. (ADI), Berkeley, CA was conducted via comparison to traditional time-integrated filter (HEADS) and impactor (MOUDI) measurements. The new monitor consists of three cascaded integrated collection and vaporization cells (ICVC) and provides 10-min resolution particulate nitrate measurements in three particle diameter size ranges (0.10-0.45, 0.45-1.0, and 1.0-2.5 w m) corresponding to observed submodes in the particle size distribution in Southern California. Side-by-side sampling was conducted for approximately six months at two sites, both at downwind receptor locations east of downtown Los Angeles. Both size-resolved and total PM 2.5 nitrate concentrations were compared among the different sampling techniques. The ADI monitor and HEADS PM 2.5 nitrate measurements, for which nitrate sampling artifacts are expected to be low, are well correlated (r 2 = 0.79) with a geometric mean ADI:HEADS ratio of 0.90. The ADI size-fractionated nitrate data measured consistently more nitrate than the corresponding MOUDI stages due to volatilization of labile ammonium nitrate from the MOUDI impaction substrates. Less disagreement was observed in the 1.0-2.5 w m size range in which nitrate is more likely to exist as nonlabile sodium nitrate. The observed MOUDI nitrate losses are attributable to existing theories of nitrate sampling efficiencies and losses. The continuous nature of the data generated by the ADI monitor will provide valuable information on the spatial and temporal distribution of particulate nitrate in the atmosphere, and the new dimension of size-fractionation can help to determine the sources and formation mechanisms of atmospheric particulate nitrate as well. Examples of the atmospheric data generated in this study are presented and the potential utility of such data provided by the new monitor are discussed.     

Review of Spark Discharge Generators for Production of Nanoparticle Aerosols

In the growing field of nanotechnology there is an increasing need to develop production methods for nanoparticles, especially methods that provide control and reproducibility. The spark discharge generator (SDG) is a versatile device for the production of nanoparticle aerosols. It can produce aerosol nanoparticles in the entire nanometer range (1–100 nm), and beyond. Depending on requirements, and the system used, these nanoparticles can be completely contamination free and composed of one or more materials. This provides a unique opportunity to create new materials on the nanoscale. Already in use in semiconductor, materials, health and environmental research, the SDG shows promise for yet more applications. If needed, particle production by the SDG could be scaled up using parallel generators facilitating continuous high-volume production of aerosol nanoparticles. Still, there is a surprisingly low knowledge of fundamental processes in the SDG. In this article we present a thorough review of the most common and relevant SDGs and the theory of their operation. Some possible improvements are also discussed.

Copyright 2012 American Association for Aerosol Research