Tissue Equivalent Curved Organic X-ray Detectors Utilizing High Atomic Number Polythiophene Analogues

Organic semiconductors are a promising material candidate for X-ray detection. However, the low atomic number (Z) of organic semiconductors leads to poor X-ray absorption thus restricting their performance. Herein, the authors propose a new strategy for achieving high-sensitivity performance for X-ray detectors based on organic semiconductors modified with high –Z heteroatoms. X-ray detectors are fabricated with p-type organic semiconductors containing selenium heteroatoms (poly(3-hexyl)selenophene (P3HSe)) in blends with an n-type fullerene derivative ([6,6]-Phenyl C71 butyric acid methyl ester (PC70BM). When characterized under 70, 100, 150, and 220 kVp X-ray radiation, these heteroatom-containing detectors displayed a superior performance in terms of sensitivity up to 600 ± 11 nC Gy−1 cm−2 with respect to the bismuth oxide (Bi2O3) nanoparticle (NP) sensitized organic detectors. Despite the lower Z of selenium compared to the NPs typically used, the authors identify a more efficient generation of electron-hole pairs, better charge transfer, and charge transport characteristics in heteroatom-incorporated detectors that result in this breakthrough detector performance. The authors also demonstrate flexible X-ray detectors that can be curved to a radius as low as 2 mm with low deviation in X-ray response under 100 repeated bending cycles while maintaining an industry-standard ultra-low dark current of 0.03 ± 0.01 pA mm−2

The genome landscape of indigenous African cattle

Background: The history of African indigenous cattle and their adaptation to environmental and human selection pressure is at the root of their remarkable diversity. Characterization of this diversity is an essential step towards understanding the genomic basis of productivity and adaptation to survival under African farming systems. Results: We analyze patterns of African cattle genetic variation by sequencing 48 genomes from five indigenous populations and comparing them to the genomes of 53 commercial taurine breeds. We find the highest genetic diversity among African zebu and sanga cattle. Our search for genomic regions under selection reveals signatures of selection for environmental adaptive traits. In particular, we identify signatures of selection including genes and/ or pathways controlling anemia and feeding behavior in the trypanotolerant N’Dama, coat color and horn development in Ankole, and heat tolerance and tick resistance across African cattle especially in zebu breeds. Conclusions: Our findings unravel at the genome-wide level, the unique adaptive diversity of African cattle while emphasizing the opportunities for sustainable improvement of livestock productivity on the continent

High sensitivity organic inorganic hybrid X-ray detectors with direct transduction and broadband response

X-ray detectors are critical to healthcare diagnostics, cancer therapy and homeland security, with many potential uses limited by system cost and/or detector dimensions. Current X-ray detector sensitivities are limited by the bulk X-ray attenuation of the materials and consequently necessitate thick crystals (~1 mm-1 cm), resulting in rigid structures, high operational voltages and high cost. Here we present a disruptive, flexible, low cost, broadband, and high sensitivity direct X-ray transduction technology produced by embedding high atomic number bismuth oxide nanoparticles in an organic bulk heterojunction. These hybrid detectors demonstrate sensitivities of 1712 µC mGy-1 cm-3 for "soft" X-rays and ~30 and 58 µC mGy-1 cm-3 under 6 and 15 MV "hard" X-rays generated from a medical linear accelerator; strongly competing with the current solid state detectors, all achieved at low bias voltages (-10 V) and low power, enabling detector operation powered by coin cell batteries

Fatty acids affect proliferation of peripheral blood mononuclear cells in dairy cows

In vitro studies were performed to assess the effects of bovine plasma fatty acids on proliferation of peripheral blood mononuclear cells (PBMC). PBMC from 6 Holstein heifers were cultured in media containing oleic (OA), palmitic (PA), stearic (SA), linoleic (LA), palmitoleic (POA), or linolenic (LNA) acid at concentrations mimicking different degree of lipomobilisation. Proliferation of PBMC was stimulated by concanavalin A or pokeweed mitogen. Concentrations of OA, PA, SA and LA mimicking moderate-intense lipomobilisation impaired PBMC proliferation. Concentrations of OA or LA mimicking low degree of lipomobilisation enhanced PBMC proliferation. None of the POA, and LNA concentrations affected proliferation of PBMC

Charged-particle spectroscopy in organic semiconducting single crystals

The use of organic materials as radiation detectors has grown, due to the easy processability in liquid phase at room temperature and the possibility to cover large areas by means of low cost deposition techniques. Direct charged-particle detectors based on solution-grown Organic Semiconducting Single Crystals (OSSCs) are shown to be capable to detect charged particles in pulse mode, with very good peak discrimination. The direct charged-particle detection in OSSCs has been assessed both in the planar and in the vertical axes, and a digital pulse processing algorithm has been used to perform pulse height spectroscopy and to study the charge collection efficiency as a function of the applied bias voltage. Taking advantage of the charge spectroscopy and the good peak discrimination of pulse height spectra, an Hecht-like behavior of OSSCs radiation detectors is demonstrated. It has been possible to estimate the mobility-lifetime value in organic materials, a fundamental parameter for the characterization of radiation detectors, whose results are equal to lscoplanar¼ (5 .5 6 0.6 ) 106 cm2 /V and lssandwich¼ (1 .9 6 0.2 ) 106 cm2 /V, values comparable to those of polycrystalline inorganic detectors. Moreover, alpha particles Time-of-Flight experiments have been carried out to estimate the drift mobility value. The results reported here indicate how charged-particle detectors based on OSSCs possess a great potential as low-cost, large area, solid-state direct detectors operating at room temperature. More interestingly, the good detection efficiency and peak discrimination observed for chargedparticle detection in organic materials (hydrogen-rich molecules) are encouraging for their further exploitation in the detection of thermal and high-energy neutrons. VC 2016 AIP Publishing LLC

Borehole flowmeter based groundwater sampling and isotopic fingerprinting support source apportionment of a public water supply well field contaminated by chlorinated pitches: the case of Bussi sul Tirino (Abruzzo region, Central Italy

A public water supply well field, composed by 8 wells attaining a depth between 32 and 62 m b.g.s. and pumping out more than 400 L/s to about 300.000 inhabitants (Pescara province, Abruzzo region, Central Italy), has been involved for more than 20 years, from the opening in 1984 to the decomissioning in 2007, by a contamination of chlorinated aliphatics (PCE, TCE, TCM, CT). The well field is located in the narrow and long alluvial valley of the Pescara river surrounded by important limestone aquifers of Central Apennines. About 2 km upstream, at the confluence of the Tirino river with the Pescara river, is located one of the oldest chemical and petrochemical plant (Bussi sul Tirino plant) in Italy. It dates back to the end of the nineteenth century and with a production of chloromethanes active from the 60's to 2007. On 2005, a huge illegal dump of industrial wastes (more than 3 hectares in size) was discovered in the alluvial valley floor of the Pescara river during an investigation of the public prosecutor of the Pescara court. The valley of the Pescara river is filled with a complex assemblage of porous (alluvial gravels and sands, debris) and fractured (travertines) high permeability aquifers intermingled with silts and clays of lacustrine or alluvial origin. The lateral recharge from the Pescara river and/or surrounding limestones is such to induce a high dilution effect to the dissolved contaminants originated at the source. In order to apportion the source of contamination, in terms of location and of process of wastes generation, in range of the action at the Court of Assizes of Chieti, an hydrogeological investigation has been performed, supported by the Italian Attorney General. CSIA (Carbon Stable Isotope Analysis) of chlorinated compounds, integrated by chlorine fingerprinting on PCE, was adopted as a main tool of source apportionment of chlorinated pitches production process. In order to enhance the mass recovery of chlorinated compounds by low flow sampling on 25 boreholes between the source and the receptor, a preliminary flowmeter survey was performed. This allowed to identify the proper sampling location along the screen of the boreholes. The isotopic affinity of the compounds, detected at the well field, with the production process of chlorinated pitches has been clearly put in evidence as a consequence of the strong deplenishment of delta13C values

Inkjet printed Organic Thin Film Transistors based tactile transducers for artificial robotic skin

We present a novel and flexible system to be employed for tactile transduction in the realization of artificial "robot skin". The mechanical deformation detection, which functionally reproduces the sense of touch, is based on Organic Thin Film Transistors (OTFTs) assembled on a flexible plastic foil, where each device acts as a strain sensor. OTFT-based mechanical sensors were fabricated employing a solution-processable organic semiconductor, namely 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) deposited by drop casting. It will be shown that the surface deformation induced by an external mechanical stimulus gives rise in both cases to a marked, reproducible, and reversible (within a certain range of surface deformation) variation of the device output current. Starting from these results, more complex structures, such as arrays and matrices of OTFT-based mechanical sensors, have been fabricated by means of inkjet printing. Thanks to the flexibility of the introduced structure, we will show that the presented system can be transferred on different surfaces (hard and soft) and employed for a wide range of applications. In particular, it can be successfully employed for tactile transduction in the realization of artificial "robot skin"