Discrete dynamics of nanoparticle channelling in suspended graphene

We have observed a previously undescribed stepwise oxidation of mono- and few layer suspended graphene by silver nanoparticles in situ at subnanometer scale in an environmental transmission electron microscope. Over the range of 600-850 K, we observe crystallographically oriented channelling with rates in the range 0.01-1 nm/s and calculate an activation energy of 0.557 ± 0.016 eV. We present a discrete statistical model for this process and discuss the implications for accurate nanoscale patterning of nanoscale systems.     

Signatures of disorder in the minimum conductivity of graphene

Graphene has been proposed as a promising material for future nanoelectronics because of its unique electronic properties. Understanding the scaling behavior of this new nanomaterial under common experimental conditions is of critical importance for developing graphene-based nanoscale devices. We present a comprehensive experimental and theoretical study on the influence of edge disorder and bulk disorder on the minimum conductivity of graphene ribbons. For the first time, we discovered a strong nonmonotonic size scaling behavior featuring a peak and saturation minimum conductivity. Through extensive numerical simulations and analysis, we are able to attribute these features to the amount of edge and bulk disorder in graphene devices. This study elucidates the quantum transport mechanisms in realistic experimental graphene systems, which can be used as a guideline for designing graphene-based nanoscale devices with improved performance.     

Recent progress in nano-biotechnology: compartmentalized micro- and nanoparticles via electrohydrodynamic co-jetting

Compartmentalized particles enable co-presentation of dissimilar sets of properties, thereby offering a broad design space for multifunctional particles. Electrohydrodynamic co-jetting is a simple, yet versatile fabrication technique that can be used to prepare such multicompartmental particles and fibers. Processing conditions are summarized for co-jetting of aqueous and organic polymer solutions as well as nanoparticle suspensions. Because particles can comprise distinct polymers in different compartments, selective surface modification becomes possible. The latter can result in unidirectional interactions with cells or may pave new routes towards targeted drug delivery.     

Effect of the Malting Barley Variety (Hordeum vulgare L) on Fermentability1

The influence of the malting barley genotype on the apparent attenuation limit (AAL) was investigated. The AAL level correlated closely with the maltose concentration in the wort but was not affected by other fermentable sugars or by the total carbohydrate content. The chemical composition, modification, amylolytic enzyme activities and several starch properties of selected malts were studied in detail. Variations in the maltose concentration could almost solely be traced back to genotype‐dependent disparities of β‐amylase thermostability. These differences are due to interallelic polymorphisms of the β‐amylase gene and are easily detected by PCR. Hence, PCR primers offer remarkable prospects for breeding barley on the basis of a marker‐assisted selection (MAS).     

Atmospheric stability of arsine and methylarsines

Arsenic (As) occurs in a variety of different chemical forms, among them volatile (gaseous) species, usually referred to as arsine and methylarsines. Here we demonstrate that arsine and methylarsines are stable in air in concentrations at the μg/L gas level. We determined half-lives of approximately 8 h under daytime conditions (UV light) for all methylated arsines, while the same species were found to be considerably more stable in night-time (dark) conditions. Arsine (AsH?) showed under both day and night-time conditions, considerably higher stabilities than methylated arsines. We show here that volatile As species seem stable enough to travel considerable distances in the atmosphere from a point source before converting into nonvolatile, oxidized compounds. Also, the degradation pathway leading to the conversion to nonvolatile compounds was investigated using computational chemistry. Arsine and methylarsines' reactions with the hydroxyl radical (?OH) as well as As-C and As-H bonds strengths in the species studied were modeled. Results showed that conversion could not be explained by H abstraction, nor by OH addition. Moreover, it was found that As-C and As-H bonds strengths are not the determining factor responsible for the decrease in stability with ascending methylation of the different volatile arsine species, as previously suggested.     

CaRch1p does not functionally interact with the high‐affinity Ca2+ influx system (HACS) of Candida albicans

The plasma membrane protein CaRch1p of Candida albicans, homologous to the human solute carrier protein SLC10A7, is involved in the regulation of calcium homeostasis. C. albicans cells lacking CaRCH1 are hypersensitive to high extracellular Ca²⁺ concentrations and show increased tolerance to ketoconazole (KCZ). We assume a higher basal Ca²⁺ influx in the rch1/rch1 mutant strain at low extracellular Ca²⁺ concentrations, which is not detrimental to C. albicans cells but may be sufficient to activate calcineurin, finally resulting in an increased tolerance to KCZ. However, at 8 µg/ml KCZ plus 3 mm Ca²⁺ the rch1/rch1 mutant and the wild‐type strains showed identical growth. By further increasing the Ca²⁺ concentration to 30 mm , this phenotype was completely reversed and the rch1/rch1 mutant strain became extremely sensitive to 8 µg/ml KCZ, probably due to synergistic toxic effects of Ca²⁺ and KCZ under these conditions. Furthermore, we aimed to clarify whether CaRch1p interacts with the Cch1p component of the voltage‐gated calcium influx channel Cch1p/Mid1p in C. albicans cells. As disruption of the two alleles of CCH1 in the rch1/rch1 mutant strain did not alter its hypersensitivity to high extracellular Ca²⁺, and as this phenotype was completely abolished by low amounts of Mg²⁺ in the rch1/rch1 mutant as well as in the cch1/cch1 rch1/rch1 double mutant, we conclude that CaRch1p is a functional component of the low‐affinity calcium uptake system (LACS) system and does not functionally interact with Cch1p. Copyright © 2013 John Wiley & Sons, Ltd.     

Rendering the Swiss railway AlpTransit safe

The safe operation of AIpTransit, apart of the planned European high-speed railway network, is a consequence of influencing factors related to construction, railway technology, and rolling stock. On the human side, operational and organisational guidelines concerning rescue measures and the adequate behaviour of people involved are equally important. The safety concept described in the paper governs and coordinates the safety planning within the different special fields and problem areas.     

Mobile computing technology at Vindigo

Developing widely useful mobile computing applications presents difficult challenges. On one hand, mobile users demand intuitive user interfaces, fast response times, and deep relevant content. On the other hand, mobile devices have limited processing, storage, power, display, and communication resources. Vindigo has taken a technology-intensive approach to meeting these challenges and has created personal navigation tools that many people find useful in their everyday lives. Vindigo's Palm OS application, introduced in March 2000, has hundreds of thousands of users and continues to attract new users rapidly. This article presents some of the technology behind Vindigo. To provide context, it first gives an overview of a typical user session. It then discusses special demands and constraints placed on mobile applications, and enumerates design principles drawn from these considerations. The rest of the article describes technology developed at Vindigo according to those principles. Throughout, it emphasizes techniques that have proven effective in delivering location-based services on today's handheld devices.     

Exploring Prostate Cancer Genome Reveals Simultaneous Losses of PTEN,FAS and PAPSS2 in Patients with PSA Recurrence after Radical Prostatectomy

The multifocal nature of prostate cancer (PCa) creates a challenge to patients’ outcome prediction and their clinical management. An approach that scrutinizes every cancer focus is needed in order to generate a comprehensive evaluation of the disease, and by correlating to patients’ clinico-pathological information, specific prognostic biomarker can be identified. Our study utilized the Affymetrix SNP 6.0 Genome-wide assay to investigate forty-three fresh frozen PCa tissue foci from twenty-three patients. With a long clinical follow-up period that ranged from 2.0–9.7 (mean 5.4) years, copy number variation (CNV) data was evaluated for association with patients’ PSA status during follow-up. From our results, the loss of unique genes on 10q23.31 and 10q23.2–10q23.31 were identified to be significantly associated to PSA recurrence (p < 0.05). The implication of PTEN and FAS loss (10q23.31) support previous reports due to their critical roles in prostate carcinogenesis. Furthermore, we hypothesize that the PAPSS2 gene (10q23.2–10q23.31) may be functionally relevant in post-operative PSA recurrence because of its reported role in androgen biosynthesis. It is suggestive that the loss of the susceptible region on chromosome 10q, which implicates PTEN, FAS and PAPSS2 may serve as genetic predictors of PSA recurrence after radical prostatectomy.