Sex Pheromone of the Click Beetle Agriotes pilosellus (Schönherr, 1718)

Agriotes pilosellus is a fairly common click beetle species distributed in open deciduous and mixed forests throughout a large area in Europe. To identify its sex pheromone, gland extracts of female beetles were analyzed using gas chromatography-mass spectrometry (GC-MS). The only volatile compounds present in the extracts were geranyl butanoate and (E)-8-hydroxygeranyl dibutanoate in a 1:3 ratio, identified by comparison with synthetic samples. Field experiments revealed a clear attraction of A. pilosellus - males towards traps baited with geranyl butanoate, which could be synergistically enhanced by the factor of almost ten by addition of (E)-8-hydroxygeranyl dibutanoate. The latter compound alone did not show any attractive effect. Both compounds correspond well to the structures known from other Agriotes species and may serve as an effective monitoring tool for entomofaunistic research.

     

Basic modelling of direct electrochemical cooling

A direct electrochemical refrigeration cycle (DERC) uses the entropy change of an electrochemical reaction to produce cooling. The cycle is Carnot limited. The electricity recycled in the DERC is much larger than the energy input to the system. Therefore, the system is sensitive to small inefficiencies in the internal energy cycling. In addition, a DERC is modelled assuming that the electrochemical cells have a constant internal resistance. By modelling the electrodes as parallel plates, an optimal channel size on the order of tens of microns can be computed depending on the electrical resistivity and viscosity of the electrolyte. The maximum cooling flux is on the order of 1000 W m⁻². Copyright © 2006 John Wiley & Sons, Ltd.     

Engineered versus standard evolutionary algorithms: A case study in batch scheduling with recourse

An engineered evolutionary algorithm for a realistic chemical batch scheduling problem with uncertain data is developed systematically. The problem is formulated as a two stage stochastic integer program with discrete scenarios. The model is solved by a stage decomposition-based hybrid algorithm using an evolutionary algorithm combined with mixed-integer programming. Earlier experiments with a standard evolutionary algorithm led to the hypothesis that the constrained search space is not covered well such that in some cases the population converges to a subset of the solution space which does not include the best known solution. An efficient engineered evolutionary algorithm is developed which is shown to cover the feasible set significantly better such that a high quality feasible schedule can be generated comparatively fast. As the hierarchical structure of the case study is typical for many batch scheduling problems, some general principles may be postulated from the experience gained here.     

Development and Validation of a Novel 11-Gene Prognostic Model for Serous Ovarian Carcinomas Based on Lipid Metabolism Expression Profile

(1) Background: Biomarkers might play a significant role in predicting the clinical outcomes of patients with ovarian cancer. By analyzing lipid metabolism genes, future perspectives may be uncovered; (2) Methods: RNA-seq data for serous ovarian cancer were downloaded from The Cancer Genome Atlas and Gene Expression Omnibus databases. The non-negative matrix factorization package in programming language R was used to classify molecular subtypes of lipid metabolism genes and the limma package in R was performed for functional enrichment analysis. Through lasso regression, we constructed a multi-gene prognosis model; (3) Results: Two molecular subtypes were obtained and an 11-gene signature was constructed (PI3, RGS, ADORA3, CH25H, CCDC80, PTGER3, MATK, KLRB1, CCL19, CXCL9 and CXCL10). Our prognostic model shows a good independent prognostic ability in ovarian cancer. In a nomogram, the predictive efficiency was notably superior to that of traditional clinical features. Related to known models in ovarian cancer with a comparable amount of genes, ours has the highest concordance index; (4) Conclusions: We propose an 11-gene signature prognosis prediction model based on lipid metabolism genes in serous ovarian cancer.     

Progress in emitter wrap-through solar cell fabrication on boron doped Czochralski-grown silicon

We report on RISE-EWT (Rear Interdigitated Single Evaporation-Emitter Wrap-Through) solar cells on full area (12.5×12.5 cm²) pseudo square boron doped Czochralski-grown silicon wafers. We investigate the main efficiency optimisation factors of these cells by investigating the dependence of RISE-EWT cell parameters on the base dopant concentration N_A. We furthermore detail the effects of large feature sizes in base and emitter regions at the rear of the solar cell and investigate these effects with particular attention to the edge regions. EWT solar cells typically exhibit rather low fill factors. However, our results show that the improved fill factors can be achieved by increasing N_A, which in return leads to optimised efficiency values. For our RISE-EWT solar cells made from boron doped Cz-Si wafers, this benefit is maintained even after light-induced degradation. Our investigation of edge area related effects shows the importance of proper cell design in these areas, leading to a further 2.8% absolute improvement in the fill factor. Combining increased base dopant concentration with optimised edge design, we achieve 19.0% efficiency on (12.5×12.5 cm²) boron doped Cz silicon wafers before light-induced degradation, resulting in 18.1% efficiency in the light-degraded state.     

Piezoresistive biochemical sensors based on hydrogels

Already 8 years ago, the usage of piezoresistive sensors for chemical measurands was proposed at the Solid State Electronics Laboratory of the Dresden University of Technology. Adding functionalised polymer coating which shows swelling due to chemical or biological values leads to a similar deflection of the thin silicon bending plate like for pressure sensors. The application of “stimuli-responsive” or “smart” cross-linked gels in chemical sensors is based on their ability to a phase transition under the influence of external excitations (pH, concentration of additives in water, temperature). Combining a “smart” hydrogel and a micro fabricated pressure sensor chip allows to continuously monitor the analyte-dependent swelling of a hydrogel and hence the analyte concentration in ambient aqueous solutions. The sensitivity of hydrogels with regard to the concentration of such additives as H⁺-ions (pH sensor), transition-metal ions, salts, organic solvents and proteins in water was investigated.     

Integrated solar panel antennas

A new antenna which combines solar cells and printed patches is presented. The antenna is designed so as to accommodate the solar cells that provide power to an MMIC amplifier. A 2×4 array is presented, which operates at the frequency of 3.76 GHz and has a bandwidth of 16% and gain up to 30 dBi (active)     

First Sex Pheromone of the Order Strepsiptera: (3R,5R,9R)-3,5,9-Trimethyldodecanal in Stylops melittae Kirby, 1802

The twisted-wing parasites (Strepsiptera) are an unusual and small order of insects with about 600 known species. As obligate endoparasitoids, they develop and spend most of their lives living in other insects. Adults show an extreme sexual dimorphism: The free-living males have large eyes, branched antennae, reduced forewings, and well developed hind wings, while the neotenic females of most species lack all external characters that normally define an insect, remain endoparasitic, and only extrude the cephalothorax from the host. Due to the males’ short life span of only a few hours, there must be an efficient means of mate finding. This is believed to be mediated by chemical cues released by virgin females. Here, we report the first identification and synthesis of a female-produced strepsipteran sex pheromone, (3R,5R,9R)-3,5,9-trimethyldodecanal, from Stylops melittae, a species parasitizing andrenid bees. We found this highly EAD-active compound to be present in cephalothoraxes of and released from unmated females, and synthetic samples proved to be extremely attractive when offered in the field during the swarming period of the males. The structural features of this new natural compound may further support the re-establishment of the Strepsiptera as the closest living relatives of the Coleoptera.     

A functional matrix metalloproteinase (MMP)-9 polymorphism modifies plasma MMP-9 levels in subjects environmentally exposed to mercury

Mercury (Hg) exposure causes health problems including cardiovascular diseases. Although precise mechanisms have not been precisely defined yet, matrix metalloproteinases (MMPs) may be involved. The gene encoding MMP-9 presents genetic polymorphisms which affect the expression and activity level of this enzyme. Two polymorphisms in the promoter region [C^− 1562T and (CA)_n] are functionally relevant, and are implicated in several diseases. This study aimed at examining how these polymorphisms affect the circulating MMP-9 levels and its endogenous inhibitor, the tissue inhibitor of metalloproteinase-1 (TIMP-1) in 266 subjects environmentally exposed to Hg. Blood and plasma Hg concentrations were determined by inductively coupled plasma-mass spectrometry (ICP-MS). MMP-9 and TIMP-1 concentrations were measured in plasma samples by gelatin zymography and ELISA, respectively. Genotypes for the C^− 1562T and the microsatellite (CA)_n polymorphisms were determined. We found a positive association (P < 0.05) between plasma Hg concentrations and MMP-9/TIMP-1 ratio (an index of net MMP-9 activity). When the subjects were divided into tertiles with basis on their plasma Hg concentrations, we found that the (CA)_n polymorphism modified MMP-9 concentrations and MMP-9/TIMP-1 ratio in subjects with the lowest Hg concentrations (first tertile), with the highest MMP-9 levels being found in subjects with genotypes including alleles with 21 or more CA repeats (H alleles) (P < 0.05). Conversely, this polymorphism had no effects on subjects with intermediate or high plasma Hg levels (second and third tertiles, respectively). The C^− 1562T polymorphism had no effects on MMP-9 levels. These findings suggest a significant interaction between the (CA)_n polymorphism and low levels of Hg exposure, possibly increasing the risk of developing diseases in subjects with H alleles.     

How important is the interfacial chemical bond for electron transport through alkyl chain monolayers?

We show that the electrode/molecule chemical bond does not change the tunneling barrier for charge transport through alkyl chain monolayers sandwiched between Si and Hg electrodes. This observation can be understood if the interfacial bond mainly governs the monolayer's structure, while the electronic states due to molecule-electrode bonding do not contribute significantly to tunneling. Yet, the nature of the bond affects the Schottky barrier inside the semiconductor due to changes in the interface dipole.