Modelling COD and N removal in the water and in the benthic biofilm for the River Wupper in Germany.

The River Wupper, a tributary of the River Rhine, is at several locations influenced by anthropogenous nitrogen input, hydraulic structures, and influents from other tributaries. These influences have an impact both on the water quality and on the hydrodynamic conditions. The model approaches used for this article are based on work of Rauch et al. and the River Water Quality Model No. 1; they allow the simulation of the nitrogen conversion in the River Wupper. They are compatible with the activated sludge models and can thus be used also for integrated approaches. The calibration and validation of the model was realized using actual data of the River Wupper over a length of 60 km with one dam, 10 weirs, three wastewater treatment plants and 11 tributaries. The model considers the nitrogen conversion and COD removal and has a strong focus on biofilm processes in the benthic zone. Additional information is given about the sedimentation processes, the physical oxygen input processes, biofilm detachment processes, molecular diffusion, the influence of the laminar border layer and the changing of COD fractions and biofilm densities.     

Complementary freeze-fracture, freeze-etch specimens

For a number of reasons, the specimens used to try to correlate the electrical and structural properties of commercial semiconductor devices often consist of a thick amorphous layer (e.g. silicon oxide) and a thinned layer of crystalline material (e.g. silicon) containing the p-n junctions. Diffraction patterns and diffraction contrast images from such specimens recorded in conventional and scanning transmission electron microscopes at 80 and 500 kV are shown. The visibility of these diffraction patterns and images depends on the mode of operation, the aperture sizes and the side on which the electrons enter the specimen. The interpretation of these results is discussed and the practical implications for imaging of such specimens are pointed out.     

Application of thin-film interference coatings in infrared reflection spectroscopy of organic samples in contact with thin metal films

A thin dielectric IR-transparent interlayer is introduced between an IR-transparent medium of incidence and a thin metal film. The interlayer increases the intensity of light on the metal/sample interface at certain wavenumbers. By computations, the reflectivities of the system "calcium fluoride (CaF)-germanium (Ge)-gold (Au) sample" are analyzed as a function of incidence angle and Ge layer thickness. Absorbance spectra with acetonitrile as a sample are recorded for different angles of incidence and polarizations and compared to computations. A characteristic feature of the absorbance spectra is the occurrence of interference fringes distributed between 1000 and 6000?cm(-1), i.e., over the complete mid-IR wavelength range into the near-IR. These fringes could be used in analytical spectroscopy.     

Demonstration of a Broadband Photodetector Based on a Two-Dimensional Metal–Organic Framework

Metal–organic frameworks (MOFs) are emerging as an appealing class of highly tailorable electrically conducting materials with potential applications in optoelectronics. Yet, the realization of their proof-of-concept devices remains a daunting challenge, attributed to their poor electrical properties. Following recent work on a semiconducting Fe₃(THT)₂(NH₄)₃ (THT: 2,3,6,7,10,11-triphenylenehexathiol) 2D MOF with record-high mobility and band-like charge transport, here, an Fe₃(THT)₂(NH₄)₃ MOF-based photodetector operating in photoconductive mode capable of detecting a broad wavelength range from UV to NIR (400–1575 nm) is demonstrated. The narrow IR bandgap of the active layer (≈0.45 eV) constrains the performance of the photodetector at room temperature by band-to-band thermal excitation of charge carriers. At 77 K, the device performance is significantly improved; two orders of magnitude higher voltage responsivity, lower noise equivalent power, and higher specific detectivity of 7 × 10⁸ cm Hz^1/2 W⁻¹ are achieved under 785 nm excitation. These figures of merit are retained over the analyzed spectral region (400–1575 nm) and are commensurate to those obtained with the first demonstrations of graphene- and black-phosphorus-based photodetectors. This work demonstrates the feasibility of integrating conjugated MOFs as an active element into broadband photodetectors, thus bridging the gap between materials' synthesis and technological applications.     

Short communication: Calculating analytical reliabilities for single-step predictions

It has been shown that single-step genomic BLUP (ssGBLUP) can be reformulated, resulting in an equivalent SNP model that includes the explicit imputation of gene contents of all ungenotyped animals in the pedigree. This reformulation reveals the underlying mechanism enabling ungenotyped animals to contribute information to genotyped animals via estimates of marker effects and consequently to the reliability of genomic predictions, a key feature generally associated with the single-step approach. Irrespective of which BLUP formulation is used for genomic prediction, with increasing numbers of genotyped animals, the marker-oriented model is recommended when calculating the reliabilities of genomic predictions. This approach has the advantage of a manageable and stable size of the model matrix that needs to be inverted to calculate analytical prediction error variances of marker effects, an advantage that also holds for prediction with the single-step model. However, when including imputed genotypes in the design matrix of marker effects, an additional imputation residual term has to be considered to account for the prediction error of imputation. We summarize some of the theoretical aspects associated with the calculation of analytical reliabilities of single-step predictions. Derivations are based on the equivalent reformulation of ssGBLUP as a marker-oriented model and the calculation of prediction error variances of marker effects. We propose 2 approximations that allow for a substantial reduction of the complexity of the matrix operations involved, while retaining most of the relevant information required for reliability calculations. We additionally provide a general framework for an implementation of single-step reliability approximation using standard animal model reliabilities as a starting point. Finally, we demonstrate the effectiveness of the proposed approach using a small example extracted from data of the routine evaluation on dual-purpose Fleckvieh (Simmental) cattle.     

Exit transport of a cyclic nucleotide from mouse L-cells

At a concentration of 30 mum, 1,4,5,6,8-pentazaacenaphthylene, 3-amino-1,5-dihydro-5-methyl-1-beta-D-[5-14C]ribofuranosyl (NSC-154020), a tricyclic, 7-deazapurine nucleoside (TCN) is rapidly taken up by cultured mouse L-cells and converted to intracellular TCN-monophosphate, but not further metabolized. The TCN-monophosphate is also excreted by the cells into the medium. It is released by a saturable process against a concentration gradient and the release is inhibited by various inhibitors of energy production. This inhibition correlates with a depletion of the cells of ATP. Thus TCN-monophosphate excretion probably involves an active transport system. This transport system is highly temperature-dependent (the Q10 falls between 3 and 4) and is inhibited by papaverine, theophylline, Persantin, Probenecid, phenethyl alcohol and p-chloromercuribenzoate, but not by 500 muM cyclic AMP, AMP, or adenosine. Significant amounts of various natural phosphorylated intermediates (AMP, ATP, UTP, UMP, UDP-hexoses, and phosphorylcholine) are not released from the cells under similar experimental conditions either in the absence or presence of 30 muM TCN.     

Extreme Optical Properties Tuned Through Phase Substitution in a Structurally Optimized Biological Photonic Polycrystal

Biological photonic structures evolved by insects provide inspiring examples for the design and fabrication of synthetic photonic crystals. The small scales covering the beetle Entimus imperialis are subdivided into irregularly shaped domains that mostly show striking colors, yet some appear colorless. The colors originate from photonic crystals consisting of cuticular material and air, which are geometrically separated by a triply periodic D‐surface (diamond). The structure and orientation of the photonic crystals are charactized and it is shown that in colorless domains SiO₂ substitutes the air. The experimental results are incorporated into a precise D‐surface structure model used to simulate the photonic band structure. The study shows that the structural parameters in colored domains are optimized for maximum reflectivity by maximizing the stop gap width. The colorless domains provide a biological example of how the optical appearance changes through alteration of the refractive index contrast between the constituting phases.     

Improving accuracy of genomic predictions within and between dairy cattle breeds with imputed high-density single nucleotide polymorphism panels

Achieving accurate genomic estimated breeding values for dairy cattle requires a very large reference population of genotyped and phenotyped individuals. Assembling such reference populations has been achieved for breeds such as Holstein, but is challenging for breeds with fewer individuals. An alternative is to use a multi-breed reference population, such that smaller breeds gain some advantage in accuracy of genomic estimated breeding values (GEBV) from information from larger breeds. However, this requires that marker-quantitative trait loci associations persist across breeds. Here, we assessed the gain in accuracy of GEBV in Jersey cattle as a result of using a combined Holstein and Jersey reference population, with either 39,745 or 624,213 single nucleotide polymorphism (SNP) markers. The surrogate used for accuracy was the correlation of GEBV with daughter trait deviations in a validation population. Two methods were used to predict breeding values, either a genomic BLUP (GBLUP_mod), or a new method, BayesR, which used a mixture of normal distributions as the prior for SNP effects, including one distribution that set SNP effects to zero. The GBLUP_mod method scaled both the genomic relationship matrix and the additive relationship matrix to a base at the time the breeds diverged, and regressed the genomic relationship matrix to account for sampling errors in estimating relationship coefficients due to a finite number of markers, before combining the 2 matrices. Although these modifications did result in less biased breeding values for Jerseys compared with an unmodified genomic relationship matrix, BayesR gave the highest accuracies of GEBV for the 3 traits investigated (milk yield, fat yield, and protein yield), with an average increase in accuracy compared with GBLUP_mod across the 3 traits of 0.05 for both Jerseys and Holsteins. The advantage was limited for either Jerseys or Holsteins in using 624,213 SNP rather than 39,745 SNP (0.01 for Holsteins and 0.03 for Jerseys, averaged across traits). Even this limited and nonsignificant advantage was only observed when BayesR was used. An alternative panel, which extracted the SNP in the transcribed part of the bovine genome from the 624,213 SNP panel (to give 58,532 SNP), performed better, with an increase in accuracy of 0.03 for Jerseys across traits. This panel captures much of the increased genomic content of the 624,213 SNP panel, with the advantage of a greatly reduced number of SNP effects to estimate. Taken together, using this panel, a combined breed reference and using BayesR rather than GBLUP_mod increased the accuracy of GEBV in Jerseys from 0.43 to 0.52, averaged across the 3 traits.     

Chiral amino acid analysis of vinegars using gas chromatography – selected ion monitoring mass spectrometry

 Twenty-five vinegars were examined quantitatively for their content of free amino acid (AA) enantiomers using chiral gas chromatography/mass spectrometry. Vinegars manufactured from grape must contained l-proline (l-Pro) as the major AA. Balsamic vinegars (aceto balsamico di Modena), with one exception, contained the highest amounts of l-AAs (861–2000 mg l^–1) as well as d-AAs (46–361 mg l^–1). The amounts of d-Pro and d-alanine (d-Ala) increased in the course of maturation. Sherry vinegars had a AA pattern similar to that of balsamic vinegars but with much lower amounts: concentrations of l-AAs were 244 mg l^–1 and 456 mg l^–1 and of d-AAs were 18 mg l^–1 and 19 mg l^–1. The l-AA content of cider vinegars was very low (34 mg l^–1 and 44 mg l^–1) and only traces of d-AAs (<2 mg l^–1) were found. In spirit vinegars few d-AAs and low amounts of most l-AAs were detected, with the exception of l-glutamic acid (l-Glu) (210–847 mg l^–1), probably added as a flavour enhancer. The AA content of spirit vinegars blended with wine vinegar was influenced by the portion of wine vinegar added. Rice vinegars had concentrations of l-AAs from as low as 36 mg l^–1 to as high as 6860 mg l^–1, and the concentrations of d-AAs ranged from 6 mg l^–1 to 531 mg l^–1. All vinegars declared as "produced by microbial fermentation" contained d-Ala, d-aspartic acid, and d-Glu as typical bacterial markers. From the data it is concluded that chiral AA analysis can be used to distinguish among fermented and synthetic vinegars and to identify raw materials used for their production. In particular, the amount of d-Pro can be used as proof of the maturation process of balsamic vinegar. Received: 11 December 1997 / Revised version: 12 May 1998     

Get on the net [Internet]

The Internet is used in engineering across the board and at all levels, from migrating current product catalogues online to business-to-business e-commerce. Not only does the Internet have benefits; it is becoming the norm in business. If you are not doing it, your competitors probably are. Most companies begin developing websites by starting small, proving value, and evolving step-by-step to become more and more complex. This article illustrates the implementation of an Internet strategy for a hypothetical electrical engineering company through this stepwise integration and examines the development outcomes