Effect of Al2O3 ALD coating on thermal stability of silica aerogel

Journal of Porous Materials - An optically transparent and thermally insulating (OTTI) silica aerogel demonstrates promising results for various solar thermal applications, particularly...     

Engineered Bacterial Flavin-Dependent Monooxygenases for the Regiospecific Hydroxylation of Polycyclic Phenols

4-Hydroxyphenylacetate 3-hydroxylase (4HPA3H), a flavin-dependent monooxygenase from E. coli that catalyzes the hydroxylation of monophenols to catechols, was modified by rational redesign to convert also more bulky substrates, especially phenolic natural products like phenylpropanoids, flavones or coumarins. Selected amino acid positions in the binding pocket of 4HPA3H were exchanged with residues from the homologous protein from Pseudomonas aeruginosa, yielding variants with improved conversion of spacious substrates such as the flavonoid naringenin or the alkaloid mimetic 2-hydroxycarbazole. Reactions were followed by an adapted Fe(III)-catechol chromogenic assay selective for the products. Especially substitution of the residue Y301 facilitated modulation of substrate specificity: introduction of nonaromatic but hydrophobic (iso)leucine resulted in the preference of the substrate ferulic acid (having a guaiacyl (guajacyl) moiety, part of the vanilloid motif) over unsubstituted monophenols. The in vivo (whole-cell biocatalysts) and in vitro (three-enzyme cascade) transformations of substrates by 4HPA3H and its optimized variants was strictly regiospecific and proceeded without generation of byproducts.     

A prediction model for personal radio frequency electromagnetic field exposure

Radio frequency electromagnetic fields (RF-EMF) in our daily life are caused by numerous sources such as fixed site transmitters (e.g. mobile phone base stations) or indoor devices (e.g. cordless phones). The objective of this study was to develop a prediction model which can be used to predict mean RF-EMF exposure from different sources for a large study population in epidemiological research. We collected personal RF-EMF exposure measurements of 166 volunteers from Basel, Switzerland, by means of portable exposure meters, which were carried during one week. For a validation study we repeated exposure measurements of 31 study participants 21 weeks after the measurements of the first week on average. These second measurements were not used for the model development. We used two data sources as exposure predictors: 1) a questionnaire on potentially exposure relevant characteristics and behaviors and 2) modeled RF-EMF from fixed site transmitters (mobile phone base stations, broadcast transmitters) at the participants' place of residence using a geospatial propagation model. Relevant exposure predictors, which were identified by means of multiple regression analysis, were the modeled RF-EMF at the participants' home from the propagation model, housing characteristics, ownership of communication devices (wireless LAN, mobile and cordless phones) and behavioral aspects such as amount of time spent in public transports. The proportion of variance explained (R²) by the final model was 0.52. The analysis of the agreement between calculated and measured RF-EMF showed a sensitivity of 0.56 and a specificity of 0.95 (cut-off: 90th percentile). In the validation study, the sensitivity and specificity of the model were 0.67 and 0.96, respectively. We could demonstrate that it is feasible to model personal RF-EMF exposure. Most importantly, our validation study suggests that the model can be used to assess average exposure over several months.     

The effects of IGF-I on bovine follicle development and IGFBP-2 expression are dose and stage dependent

This study aimed to determine the effect of insulin-like growth factor-I (IGF-I) on early antral bovine follicular development, and the expression of insulin-like growth factor-binding protein-2 (IGFBP-2). Antral follicles separated into three different size groups were cultured for 6 days in medium supplemented with either a low (10 ng/ml) or high (1 microg/ml) dose of human recombinant IGF-I. Oestradiol production by follicles in all size ranges, cultured in the presence of the high concentration of IGF-I, significantly increased by day 6 (P < 0.05). Follicles in the smallest size range, 165-215 microm, cultured in a high dose of IGF-I, were found to be significantly increased in size (P < 0.01). Oocyte health of the largest follicles (281-380 microm) was significantly improved by the addition of IGF-I to the culture medium. mRNA expression of IGFBP-2 was decreased in the granulosa cells of follicles, size range 216-280 microm, cultured with a high dose of IGF-I (P < 0.05). Granulosa cells (P < 0.05) and oocytes (P < 0.01) of the largest follicles (281-380 microm) showed a decrease in IGFBP-2 expression (protein) when cultured in the control and low-IGF-I treatment groups. Therefore, the response of a bovine follicle to IGF-I is both dose and stage dependent. This work supports a role for IGF-I in modulating somatic and germ-cell maturation and development in early antral follicles. Furthermore, the inverse relationship between the level of IGF-I stimulation and IGFBP-2 expression suggests a local regulatory system modulating IGF-I availability.     

Effect pigments for textile coating: a review of the broad range of advantageous functionalization

The presented review will introduce the use of effect pigments as a powerful tool for the functionalization of textiles. This review starts with a short introduction on the basics of effect pigments and their properties. Subsequently, some principles of effect pigment application onto textiles and the interaction of pigment to binder systems are reported. Different possible functionalizations realized on textiles are presented. Four main types of application are discussed: optical properties, electrical properties, barrier coatings, and antimicrobial applications. Also a view of some prospective anisotropic materials is given. Altogether it is shown that the application of effect pigments can be a powerful tool to realize functional textiles for a broad range of applications in different fields.     

Spectral fluorometric characterization of phytoplankton community composition using the Algae Online Analyser

The utility of a multiple-fixed-wavelength spectral fluorometer, the Algae Online Analyser (AOA), as a means of quantifying phytoplankton biomass and community composition was tested using natural communities from two southeastern United States estuaries, North Inlet, South Carolina, and the Neuse River Estuary, North Carolina. Estimates of biomass (as chlorophyll a) were correlated with HPLC values and variations (usually over-estimates) were consistent with effects of light intensity and nutrient availability on fluorescence quenching. AOA estimates of taxonomic structure were consistent with those from HPLC-derived marker pigments by ChemTax, with both methods indicating domination by chromophytes and green algae in North Inlet and chromophytes and cyanobacteria in the Neuse. We recommend frequent calibration by discrete sample collection, and calibration with species representative of the region of interest. Overall, the AOA appears to be a useful tool for monitoring of phytoplankton community composition, especially as an early warning system for the detection of harmful algal blooms.     

Multicolor 3D Orbital Tracking

Feedback-based single-particle tracking (SPT) is a powerful technique for investigating particle behavior with very high spatiotemporal resolution. The ability to follow different species and their interactions independently adds a new dimension to the information available from SPT. However, only a few approaches have been expanded to multiple colors and no method is currently available that can follow two differently labeled biomolecules in 4 dimensions independently. In this proof-of-concept paper, the new modalities available when performing 3D orbital tracking with a second detection channel are demonstrated. First, dual-color tracking experiments are described studying independently diffusing particles of different types. For interacting particles where their motion is correlated, a second modality is implemented where a particle is tracked in one channel and the position of the second fluorescence species is monitored in the other channel. As a third modality, 3D orbital tracking is performed in one channel while monitoring its spectral signature in a second channel. This last modality is used to successfully readout accurate Förster Resonance Energy Transfer (FRET) values over time while tracking a mobile particle.     

Proteomic characterization of differentially expressed proteins in breast cancer: Expression of hnRNP H1, RKIP and GRP78 is strongly associated with HER-2/neu status

The human epidermal growth factor receptor type 2 (HER‐2/neu) oncoprotein is overexpressed in about 30% of breast cancers and associates with metastatic phenotypes of breast tumours. Dissecting the HER‐2/neu‐modulated molecules in cancer will be helpful in elucidating the underlying molecular mechanisms of HER‐2/neu‐driven tumourigenesis. We investigated the differential proteome profiles between microdissected HER‐2/neu‐positive and ‐negative tumours and unambiguously identified 21 proteins with diverse biological functions by peptide sequencing and NCBInr database interrogation. Six proteins were up‐regulated whereas 15 were down‐regulated in the HER‐2/neu‐positive tumours. Differential expressions of heterogeneous nuclear ribonucleoprotein H1 (hnRNP H1), 78 kDa glucose‐regulated protein (GRP78/Bip) and Raf‐1 kinase inhibitor protein (RKIP), which have not been previously reported as being linked to HER‐2/neu signalling, were further verified. Immunohistochemical staining on tissue microarray sections demonstrated a positive correlation of hnRNP H1 (p = 0.008) and negative correlations of GRP78 and RKIP (p = 0.018 and 0.013, respectively) with HER‐2/neu. Heregulin α1 enhanced hnRNP H1, but reduced GRP78 and RKIP expression in BT474 cells in a dose‐dependent manner, providing evidence of crosstalk between HER‐2/neu signalling and these modulators. Our studies have identified novel modulators that are likely to be intricately involved in HER‐2/neu‐driven tumour proliferation, invasion and metastasis.     

Droplet mixing using electrically tunable superhydrophobic nanostructured surfaces

We demonstrate effective mixing of microliter droplets using electrically tunable superhydrophobic nanostructured surfaces. By applying electrical voltage and current, droplets can be reversibly switched from a wetting to a non-wetting state, which induces fluid motion within the droplet. This mixing concept was verified using a DNA hybridization assay, in which a single droplet reversibility accelerated the hybridization reaction by an order of magnitude as compared to mixing by passive diffusion. This work offers a new method to effectively mix droplets for a variety of microfluidics applications.