bluuebunny/crossref_metadata_2025 huggingface dataset:
The Performance of the NRPB Radon Personal Dosemeter
Authors: Bartlett D.T. , Gilvin P.J. , Dixon D.W. , Solanki H.L. , Miles J.C.H.
Published: February 2017

The NRPB has developed a radon personal dosemeter for use in mines. The dosemeter is being introduced into operational service subject to approval by the appropriate authorities. The principle of operation of the dosemeter is established both experimentally and theoretically. The dosemeter acts as a radon diffusion chamber, excluding radon progeny and detritus, limiting access of moisture but allowing relatively free access of radon gas. The alpha particles from the decay of radon and its progeny are recorded in a piece of polyallyl diglycol carbonate (PADC). The net density of the electrochemically etched pits is proportional to the time integral of the radon gas concentration external to the dosemeter. Prior to its introduction, trials of the dosemeter have been carried out in various mines in the United Kingdom. These trials were in addition to laboratory investigations of the performance of the dosemeter under simulated miners' conditions. The performance of the dosemeter is reported in terms of its ability to measure the time integral of the radon gas concentration unaffected by the environmental condition.
The Characteristics of New LiF Preparations and Sensitised LiF
Authors: Driscoll C.M.H. , McWhan A.F. , O'Hagan J.B. , Dodson J. , Mundy S.J. , Todd C.D.
Published: February 2017

The patent governing the preparation and production of lithium fluoride (LiF) awarded to the Harshaw Chemical Co. has expired. Other companies have become interested in developing additional preparations of this material. Two of these preparations include LiF:Mg,Ti manufactured by Vinten Instruments plc and high sensitivity LiF:Mg,Cu,P distributed by them. The properties of these materials, including sensitivity, dose threshold, photon energy response, re-usability and storage characteristics, are presented in this paper and compared with those of Harshaw TLD-100 and with those of sensitised LiF.
Measurement of Extremely Low Level Dose with LiF(Mg,Cu,P) TL Chips
Authors: Ziying Z. , Shoushan W. , Fang W. , Guolong C. , Yuanfang L. , Jianhuan Z.
Published: February 2017

This paper presents some of the dosimetric characteristics of newly developed LiF(Mg,Cu,P) TL chips with high signal-to-noise ratio for measurement at the 10-7 to 10-4 Gy dose level. Measuring techniques and optimum procedures for annealing and readout are also presented.
Energy Response of Hot-Pressed Thin Layer Detectors to Photon and Electron Irradiations
Authors: Holzapfel G. , Lesz J. , Petel M. , Scharmann A.
Published: February 2017

Hot-pressed thin layer detectors for integrating solid state dosemeters (C/B/Al2O3/LiF:Mg,Ti and Al/Al2O3/LiF:Na,Mg,Ti structures) were investigated with respect to sensitivity for X and ? irradiations with different energies (6 keV - 1 MeV) and variable radiation incidence (±60o isotropy) with and without the presence of phantoms. TL and TSEE readouts showed characteristic over- and under-estimations of the applied doses. The TL response of the new detectors to ß irradiations (90Sr-90Y, 204Tl, 147Pm) meets the requirements of practice by decreasing only for the low energy electron source.
Parallel-to-Anode Alpha Probe in a Cylindrical TEPC at Simulated Lengths Less than 1 µm
Authors: Colautti P. , Leuthold G. , Talpo G. , Tornielli G.
Published: February 2017

The renewed interest in radiation ionisation patterns in volumes of a few nanometres in size encourages the employment of tissue-equivalent proportional counters (TEPC) at very low counting gas pressures in order to simulate lengths of less than 1 µm. In this condition the counters work at such reduced electrical fields that there is no reliable theory available that can describe these avalanche characteristics in detail. An experimental set-up has been developed to measure the limit between drift and avalanche regions in a TEPC by employing an ion probe which can be positioned at different radial distances from the collecting anode. Results obtained with an a particle probe are reported. The determination of the avalanche limit is uncertain because of the relevant d ray cloud which makes the probe size larger than that defined by the collimators. Nevertheless, the results are encouraging, and they suggest that a better description of the working limits of a cylindrical proportional counter at low pressure is possible by employing a more suitable probe as a low energy ion beam.
Microdosimetric Characterisation of Radiation Fields with a High Pressure Ionisation Chamber: A Comparison with the Low Pressure Proportional Counter
Authors: Makrigiorgos G.M. , Waker A.J. , Kassis A.I.
Published: February 2017

The application is described of a tissue-equivalent (TE) high pressure ionisation chamber that permits evaluation of the mean quality factor in mixed neutron-gamma radiation fields and compares the data obtained with those acquired with a TE proportional counter (Rossi counter). Irradiations are produced by a research fission reactor. The radiation spectrum composition is modified by moderating the beam by various heavy water (D2O) or lead thicknesses and by inserting boral shutters in the neutron beam. Thus, radiation fields with most of the radiation dose originating from thermal neutrons or fast neutrons are obtained, with associated gamma ray absorbed doses ranging from 35% to 90%. The mean quality factors derived are in agreement (±10%) for situations where most of the radiation dose is due to fast neutrons. When most of the delivered dose is due to thermal or intermediate neutrons, the Rossi counter systematically predicts smaller (30 to 40%) quality factors than the high pressure TE chamber, this observation being confirmed on theoretical grounds, as most of the neutrons interacting with the Rossi counter do not cross the counter at these energies (i.e. they are 'stoppers'). The practical advantages and disadvantages of using either instrument in a particular situation are discussed.
The Contribution of OH* in Densely Ionising Electron Track Ends or Particle Tracks to the Induction of DNA Double Strand Breaks
Authors: Frankenberg D. , Frankenberg-Schwager M. , Harbich R.
Published: February 2017

The extent of the OH* -mediated induction of DNA double strand breaks (DSB) was determined for sparsely ionising 25 MeV electrons and for densely ionising 4.2 MeV alpha particles. Using haploid yeast cells which, in stationary phase, are not capable of DSB repair, DSB induction can be determined simply by measuring cell survival of these cells. The OH* -mediated DSB induction for 25 MeV electrons amounts to 27% under anoxic and 60% under oxic conditions whereas for 4.2 MeV a particles these contributions are 44% and 53%, respectively. For 25 MeV electrons the OER value of the OH* -mediated DSB induction is 5.9 whereas it is only 1.5 for the direct effect. For 4.2 MeV a particles the OER values are 1.4 (OH* -mediated) and 1.0 (direct).
Oncogenic Transformation Induced by High and Low LET Radiations
Authors: Bettega D. , Calzolari P. , Ottolenghi A. , Tallone Lombardi L.
Published: February 2017

Cytotoxicity and oncogenic transformation incidence were studied in C3H 10T1/2 cells irradiated with 4.3 MeV alpha particles and were compared with results previously obtained with low LET protons. The alpha particles were more effective than low LET protons both in cell inactivation and for oncogenic transformation. The survival curve with alpha particles was an exponential function of the dose with a mean lethal dose of 0.61 ± 0.02 Gy. The corresponding RBE was a decreasing function of the dose varying from 15 to 4 when alpha particle doses ranged from 0.1 to 2 Gy. The transformation curves show complex shapes with a region of apparent constancy at low doses followed by a linear increase with dose. RBE values decreased from 20 to 4 in the dose region between 0.1 and 2 Gy. There was a significant transformation incidence at doses that have very little effect on cell survival. No effect of the dose rate was found at total doses of 0.05 and 0.1 Gy with dose rates of 0.11 and 0.005 Gy.min-1.
The Microdosimetry of Radon Decay Products in the Respiratory Tract
Authors: Hui T.E. , Poston J.W. , Fisher D.R.
Published: February 2017

The purpose of this study was to develop methods for calculating the probability density in specific energy for cell nuclei of the respiratory tract epithelium irradiated by inhaled radon and daughter products. Microdosimetry also provides the probability that cell nuclei may be hit by alpha particles, the probability that cell nuclei are completely missed, and the mean (absorbed) dose to cell nuclei. Such information is useful for interpreting the significance of an inhalation exposure to radon and daughters. The secretory and basel cell nuclei were considered separately as potential targets of biological importance for exposure to radon daughters. A 30 day (0.023 WLM) and a 30 year (8.45 WLM) exposure to a reference atmosphere representing an average exposure to the US population to a radon concentration of 37 Bq.m-3 (1 pCi.l-1) in disequilibrium with its daughters were considered for sample calculations. About 0.3% and 10% of cell nuclear sites would be hit once for 30 day and 30 year exposures, respectively. Most cell nuclear sites (80-90%) would be missed by the 30 year exposure to alpha particles. The main, lobar, and segmental bronchi (generations 1-4) have the highest fraction of cell nuclei irradiated; these are also the epithelial tissues from which most bronchial tumours originate in humans exposed to radon atmospheres. The average 30 year reference atmosphere doses to secretory and basal cell nuclei in the segmental bronchi were 0.3 Gy and 0.2 Gy (30 rad and 20 rad), respectively. These values correspond to 0.035 Gy.WLM-1 and 0.024 Gy.WLM-1, respectively. For the whole bronchial tree, the average absorbed dose per unit exposure was 0.014-0.015 Gy.WLM-1 (1.4-1.5 rad.WLM-1).
The Distribution of Intergranular Gaps Along Alpha Tracks Recorded in Ionographic Emulsions
Authors: Wittendorp-Rechenmann E. , Senger B. , Koziel-Vigneron V. , Rechenmann R.V.
Published: February 2017

Detailed microscopic analyses performed at high statistics (size: 1100) on 8.776 MeV a tracks materialised in nuclear emulsion demonstrated a distribution of intergranular gaps along the primary ion's path that was not only non-random but also fluctuated significantly with the energy of the projectile. The highest and lowest gap frequencies measured correspond to the energy region of 0.07 - 1.5 MeV and 7 MeV, respectively. The gap length distributions followed an exponential law, a known characteristic of the intergranular gaps distributed along the tracks of high energy charged particles. A tentative interpretation of these observations has been undertaken in terms of spatial distributions of d rays around the incoming ion's path, by applying the Double-Differential Cross-Section Mixed Treatment to the geometrical configuration of the AgBr microcrystals embedded in the gelatin matrix. At this preliminary stage of our modelling, the main experimental data could already be reproduced satisfactorily.
Thermoluminescent Characterisation of MgB4O7:Dy Sintered Pellets
Authors: Campos L.L. , Fernandes Filho O.O.
Published: February 2017

Solid MgB4O7:Dy pellets have recently been produced at the Instituto de Pesquisas Energéticas e Nucleares (IPEN). Results on annealing, glow curve, exposure and energy response, fading and reproducibility of the pellets are presented.
Phototransferred Thermoluminescence in Calcite
Authors: Lima J.F. , Trzesniak P. , Yoshimura E.M. , Okuno E.
Published: February 2017

The effect of ultraviolet (UV) radiation on the thermoluminescent properties of Brazilian calcite was studied, using both untreated (without any treatment in the laboratory) and treated samples (with a heat treatment at 400 oC for 1 h followed by a gamma ray exposure of 7.5 C.Kg-1). The glow curve of the untreated samples showed peaks at 250 oC (peak 2) and 350 oC (peak 3), while the treated samples presented an additional peak at 150 oC (peak 1). Thermal bleaching was performed on treated samples in order to empty the traps corresponding to either peak 1 or peaks 1 and 2. UV exposure following this procedure caused the reappearance of the erased peaks, at the expense of the peaks related to the deeper traps. The experimental results can be explained by the phototransference of charge carriers.
The Variation of TL Properties of Synthetic Quartz by Thermal Annealing
Authors: Kristianpoller N. , Abu-Rayya M. , Chen R.
Published: February 2017

The previously reported supralinear dependence of the 110 oC peak in synthetic quartz on the dose of beta excitation has been further studied. The transition from strong supralinearity to linear or weak supralinear behaviour has been investigated in some detail. In the unannealed material, an initial more than quadratic dose dependence has been observed, behaving like Dk where D is the dose and k a number up to 3. Annealing at high temperature increased substantially the initial sensitivity and reduced the degree of supralinearity. The transition occurs between 500 and 1000 oC, depending partly on the grain size. In this temperature range the initial sensitivity increases by at least an order of magnitude, and the dose dependence reduces gradually, in some cases down to near linearity. In intermediate temperature annealings within the above mentioned range, a transition between low and high values of the supralinearity factor k has been found in the dose dependence curve, which seems to shed some new light on the understanding of supralinearity in this material.
Phototransferred Thermoluminescence in Quartz
Authors: Milanovich-Reichhalter I. , Vana N.
Published: February 2017

After a and ß irradiation of fine-grain samples from quartz annealed at 650 oC three PTTL peaks appear at 100 oC, 150 oC and 195 oC after first readout up to 245 oC and UV illumination. Two different wavelengths, 315 nm and 275 nm cause the most significant PTTL. The peak heights of the PTTL peaks depend on illumination time. The peak at 100 oC saturates after 4 min, the peaks at 150 oC and 195 oC after 30 min of illumination. The PTTL peaks are filled from a peak with a maximum at about 325 oC. The efficiency of the phototransfer process depends on illumination wavelength and illumination time and is different after a irradiation and ß irradiation.
Corrections to Gamma Ray Dosimetry Measurements Made in Harwell's Two High Intensity Filtered Neutron Beams using 7LiF Thermoluminescent Dosemeters Owing to their Neutron Sensitivity
Authors: Croft S. , Perks C.A.
Published: February 2017

Two high intensity filtered neutron beams have been developed at the Harwell Laboratory using the high flux reactors DIDO and PLUTO as neutron sources. The beams have been used to irradiate biological cells, in free air and at various depths in a polyethylene phantom, in order to assess the potential of intermediate energy neutrons for the treatment of brain tumours using Boron Neutron Capture Therapy (BNCT). For the purpose of these studies, the gamma ray dose rates in the open beam and at depths in the polyethylene phantom were measured using 7LiF thermoluminescent dosemeters (TLDs), with the assumption that their sensitivity to neutrons is negligible. Because of this assumption the gamma ray dose rate estimates obtained are too high. In this paper an estimate of the spectrum averaged neutron sensitivity of 7LiF TLD material is made using the measured neutron fluence rate spectrum of the beam and the calculated neutron fluence rate profile with depth in the polyethylene phantom, together with evaluated data on the neutron sensitivity of 7LiF TLD taken from the literature. It is found that the largest correction occurs within the first few centimetres of the polyethylene phantom where the thermal neutron fluence rate to ? dose rate peaks. The effect of this correction is to reduce the measured gamma ray dose rates between 0.7% and 17% depending on the isotopic composition of the lithium in dosemeters. Appropriate correction factors as a function of depth in the polyethylene phantom for a representative range of 6Li/7Li ratios are presented.
Inter- and intraspecific phenotypic plasticity of three phytoplankton species in response to ocean acidification
Authors: Hattich Giannina S. I. , Listmann Luisa , Raab Julia , Ozod-Seradj Dorthe , Reusch Thorsten B. H. , Matthiessen Birte
Published: February 2017

Phenotypic plasticity describes the phenotypic adjustment of the same genotype to different environmental conditions and is best described by a reaction norm. We focus on the effect of ocean acidification on inter- and intraspecific reaction norms of three globally important phytoplankton species (Emiliania huxleyi, Gephyrocapsa oceanicaandChaetoceros affinis). Despite significant differences in growth rates between the species, they all showed a high potential for phenotypic buffering (similar growth rates between ambient and high CO2conditions). Only three coccolithophore genotypes showed a reduced growth in high CO2. Diverging responses to high CO2of single coccolithophore genotypes compared with the respective mean species responses, however, raise the question of whether an extrapolation to the population level is possible from single-genotype experiments. We therefore compared the mean response of all tested genotypes with a total species response comprising the same genotypes, which was not significantly different in the coccolithophores. Assessing species reaction norms to different environmental conditions on short time scale in a genotype-mix could thus reduce sampling effort while increasing predictive power.
Ocean acidification alters predator behaviour and reduces predation rate
Authors: Watson Sue-Ann , Fields Jennifer B. , Munday Philip L.
Published: February 2017

Ocean acidification poses a range of threats to marine invertebrates; however, the emerging and likely widespread effects of rising carbon dioxide (CO
2
) levels on marine invertebrate behaviour are still little understood. Here, we show that ocean acidification alters and impairs key ecological behaviours of the predatory cone snail
Conus marmoreus
. Projected near-future seawater CO
2
levels (975 µatm) increased activity in this coral reef molluscivore more than threefold (from less than 4 to more than 12 mm min
−1
) and decreased the time spent buried to less than one-third when compared with the present-day control conditions (390 µatm). Despite increasing activity, elevated CO
2
reduced predation rate during predator–prey interactions with control-treated humpbacked conch,
Gibberulus gibberulus gibbosus
; 60% of control predators successfully captured and consumed their prey, compared with only 10% of elevated CO
2
predators. The alteration of key ecological behaviours of predatory invertebrates by near-future ocean acidification could have potentially far-reaching implications for predator–prey interactions and trophic dynamics in marine ecosystems. Combined evidence that the behaviours of both species in this predator–prey relationship are altered by elevated CO
2
suggests food web interactions and ecosystem structure will become increasingly difficult to predict as ocean acidification advances over coming decades.
Frogs use a viscoelastic tongue and non-Newtonian saliva to catch prey
Authors: Noel Alexis C. , Guo Hao-Yuan , Mandica Mark , Hu David L.
Published: February 2017

Frogs can capture insects, mice and even birds using only their tongue, with a speed and versatility unmatched in the world of synthetic materials. How can the frog tongue be so sticky? In this combined experimental and theoretical study, we perform a series of high-speed films, material tests on the tongue, and rheological tests of the frog saliva. We show that the tongue's unique stickiness results from a combination of a soft, viscoelastic tongue coupled with non-Newtonian saliva. The tongue acts like a car's shock absorber during insect capture, absorbing energy and so preventing separation from the insect. The shear-thinning saliva spreads over the insect during impact, grips it firmly during tongue retraction, and slides off during swallowing. This combination of properties gives the tongue 50 times greater work of adhesion than known synthetic polymer materials such as the sticky-hand toy. These principles may inspire the design of reversible adhesives for high-speed application.
Fundamental limitations of network reconstruction from temporal data
Authors: Angulo Marco Tulio , Moreno Jaime A. , Lippner Gabor , Barabási Albert-László , Liu Yang-Yu
Published: February 2017

Inferring properties of the interaction matrix that characterizes how nodes in a networked system directly interact with each other is a well-known network reconstruction problem. Despite a decade of extensive studies, network reconstruction remains an outstanding challenge. The fundamental limitations governing which properties of the interaction matrix (e.g. adjacency pattern, sign pattern or degree sequence) can be inferred from given temporal data of individual nodes remain unknown. Here, we rigorously derive the necessary conditions to reconstruct any property of the interaction matrix. Counterintuitively, we find that reconstructing any property of the interaction matrix is generically as difficult as reconstructing the interaction matrix itself, requiring equally informative temporal data. Revealing these fundamental limitations sheds light on the design of better network reconstruction algorithms that offer practical improvements over existing methods.
Challenges to deployment of twenty-first century nuclear reactor systems
Authors: Ion Sue
Published: February 2017

The science and engineering of materials have always been fundamental to the success of nuclear power to date. They are also the key to the successful deployment and operation of a new generation of nuclear reactor systems and their associated fuel cycles. This article reflects on some of the historical issues, the challenges still prevalent today and the requirement for significant ongoing materials R&D and discusses the potential role of small modular reactors.
A phosphorus threshold for mycoheterotrophic plants in tropical forests
Authors: Sheldrake Merlin , Rosenstock Nicholas P. , Revillini Daniel , Olsson Pål Axel , Wright S. Joseph , Turner Benjamin L.
Published: February 2017

The majority of terrestrial plants associate with arbuscular mycorrhizal (AM) fungi, which typically facilitate the uptake of limiting mineral nutrients by plants in exchange for plant carbon. However, hundreds of non-photosynthetic plant species—mycoheterotrophs—depend entirely on AM fungi for carbon as well as mineral nutrition. Mycoheterotrophs can provide insight into the operation and regulation of AM fungal relationships, but little is known about the factors, fungal or otherwise, that affect mycoheterotroph abundance and distribution. In a lowland tropical forest in Panama, we conducted the first systematic investigation into the influence of abiotic factors on the abundance and distribution of mycoheterotrophs, to ask whether the availability of nitrogen and phosphorus altered the occurrence of mycoheterotrophs and their AM fungal partners. Across a natural fertility gradient spanning the isthmus of Panama, and also in a long-term nutrient-addition experiment, mycoheterotrophs were entirely absent when soil exchangeable phosphate concentrations exceeded 2 mg P kg
−1
. Experimental phosphorus addition reduced the abundance of AM fungi, and also reduced the abundance of the specific AM fungal taxa required by the mycoheterotrophs, suggesting that the phosphorus sensitivity of mycoheterotrophs is underpinned by the phosphorus sensitivity of their AM fungal hosts. The soil phosphorus concentration of 2 mg P kg
−1
also corresponds to a marked shift in tree community composition and soil phosphatase activity across the fertility gradient, suggesting that our findings have broad ecological significance.
Multiple kinesin-14 family members drive microtubule minus-end-directed transport in plant cells
Authors: Yamada Moé , Tanaka-Takiguchi Yohko , Hayashi Masahito , Nishina Momoko , Goshima Gohta
Published: February 2017

Minus-end-directed cargo transport along microtubules (MTs) is exclusively driven by the molecular motor dynein in a wide variety of cell types. Interestingly, plants have lost the genes encoding dynein during evolution; the MT motors that compensate for dynein function are unknown. Here, we show that two members of the kinesin-14 family drive minus-end-directed transport in plants. Gene knockout analyses of the mossPhyscomitrella patensrevealed that the plant-specific class-VI kinesin-14, KCBP, is required for minus-end-directed transport of the nucleus and chloroplasts. Purified KCBP directly bound to acidic phospholipids (PLs) and unidirectionally transported PL liposomes along MTsin vitro. Thus, minus-end-directed transport of membranous cargoes might be driven by their direct interaction with this motor protein. Newly nucleated cytoplasmic MTs represent another known cargo exhibiting minus-end-directed motility, and we identified the conserved class-I kinesin-14 (ATK) as the motor involved. These results suggest that kinesin-14 motors were duplicated and developed as alternative MT-based minus-end-directed transporters in land plants.
Medicago truncatulacopper transporter 1 (MtCOPT1) delivers copper for symbiotic nitrogen fixation
Authors: Senovilla Marta , Castro-Rodríguez Rosario , Abreu Isidro , Escudero Viviana , Kryvoruchko Igor , Udvardi Michael K. , Imperial Juan , Guerrero Manuel González
Published: February 2017

• Copper is an essential nutrient for symbiotic nitrogen fixation. This element is delivered by the host plant to the nodule, where membrane copper transporter would introduce it into the cell to synthesize cupro-proteins.

• COPT family members in model legumeMedicago truncatulawere identified and their expression determined. Yeast complementation assays, confocal microscopy, and phenotypical characterization of aTnt1insertional mutant line were carried out in the nodule-specificM.truncatulaCOPT family member.

•Medicago truncatulagenome encodes eight COPT transporters.MtCOPT1(Medtr4g019870) is the only nodule-specificCOPTgene. It is located in the plasma membrane of the differentiation, interzone and early fixation zones. Loss of MtCOPT1 function results in a copper-mitigated reduction of biomass production when the plant obtains its nitrogen exclusively from symbiotic nitrogen fixation. Mutation ofMtCOPT1results in diminished nitrogenase activity in nodules, likely an indirect effect from the loss of a copper-dependent function, such as cytochrome oxidase activity incopt1-1bacteroids.

• These data are consistent with a model in which MtCOPT1 transports copper from the apoplast into nodule cells to provide copper for essential metabolic processes associated with symbiotic nitrogen fixation.
Meta-analysis of the variance ratio
Authors: Traut Nicolas
Published: February 2017

Introduction

The most commonly used effect size when using meta-analysis to compare a measurement of interest in two different populations is the standardised mean difference. This is the mean difference of the measurement divided by the pooled standard deviation in the two groups. The standard deviation is usually supposed to be the same for both groups, although this assumption is often made without any particular evidence. It is possible, however, that the difference of the measurement in the two populations resides precisely in their standard deviations. This could be the case, for example, if a population of patients exhibited more “abnormal” values than a control population – both large and small – even if the mean values were the same. Fisher’s test of equality of variance is designed to compare standard deviations. A variance ratio is a Fisher’s ratio and Fisher distribution can be used to give confidence intervals to the estimate for one study. However, confidence interval for one study can be very wide if the study does not contain enough subjects. Here we present an approach to combine variance ratios of different studies in a meta-analytic way which produces more robust estimates under these circumstances.
Large-Scale Immunoprecipitation from Fission Yeast Cell Extracts
Authors: Grallert Agnes , Hagan Iain M.
Published: February 2017

We outline immunoprecipitation (IP) procedures to isolate the large quantities of a molecule of interest that are required to identify posttranslational modifications (PTMs) in subsequent targeted mass spectrometry analysis. In situ denaturation by trichloroacetic acid precipitation inhibits the activities of modifying enzymes that could alter the PTM profile to preserve the PTMs on a target of interest throughout the precipitation step. In contrast, isolation of the same molecule with the nondenaturing variation on this IP procedure can maintain associations with partner molecules whose PTMs can also be mapped, albeit with the caveat that modifications could have occurred during the extended IP period.
Viral Vector-Based Transduction of Slice Cultures
Authors: Wiegert J. Simon , Gee Christine E. , Oertner Thomas G.
Published: February 2017

Transgenes can be introduced into the cells of organotypic slice cultures using different delivery methods, such as biolistic transfection, electroporation, and viral vector-based transduction. These methods produce different patterns of transgene expression. Local injection of recombinant adeno-associated virus (rAAV) produces a small cluster of transgene-expressing neurons around the injection site. Expression in individual cells varies with the distance from the injection site, indicating that many neurons take up several rAAV particles. The serotype and promoter also play a role in transgene expression. Here, we present a protocol for the transduction of previously prepared hippocampal slice cultures with rAVV.
Development of new CdZnTe detectors for room-temperature high-flux radiation measurements
Authors: Abbene Leonardo , Gerardi Gaetano , Raso Giuseppe , Principato Fabio , Zambelli Nicola , Benassi Giacomo , Bettelli Manuele , Zappettini Andrea
Published: February 2017

Recently, CdZnTe (CZT) detectors have been widely proposed and developed for room-temperature X-ray spectroscopy even at high fluxes, and great efforts have been made on both the device and the crystal growth technologies. In this work, the performance of new travelling-heater-method (THM)-grown CZT detectors, recently developed at IMEM-CNR Parma, Italy, is presented. Thick planar detectors (3 mm thick) with gold electroless contacts were realised, with a planar cathode covering the detector surface (4.1 mm × 4.1 mm) and a central anode (2 mm × 2 mm) surrounded by a guard-ring electrode. The detectors, characterized by low leakage currents at room temperature (4.7 nA cm−2 at 1000 V cm−1), allow good room-temperature operation even at high bias voltages (>7000 V cm−1). At low rates (200 counts s−1), the detectors exhibit an energy resolution around 4% FWHM at 59.5 keV (241Am source) up to 2200 V, by using commercial front-end electronics (A250F/NF charge-sensitive preamplifier, Amptek, USA; nominal equivalent noise charge of 100 electrons RMS). At high rates (1 Mcounts s−1), the detectors, coupled to a custom-designed digital pulse processing electronics developed at DiFC of University of Palermo (Italy), show low spectroscopic degradations: energy resolution values of 8% and 9.7% FWHM at 59.5 keV (241Am source) were measured, with throughputs of 0.4% and 60% at 1 Mcounts s−1, respectively. An energy resolution of 7.7% FWHM at 122.1 keV (57Co source) with a throughput of 50% was obtained at 550 kcounts s−1 (energy resolution of 3.2% at low rate). These activities are in the framework of an Italian research project on the development of energy-resolved photon-counting systems for high-flux energy-resolved X-ray imaging.
Isothermal equation of state and high-pressure phase transitions of synthetic meridianiite (MgSO4·11D2O) determined by neutron powder diffraction and quasielastic neutron spectroscopy
Authors: Fortes A. Dominic , Fernandez-Alonso Felix , Tucker Matthew , Wood Ian G.
Published: February 2017

We have collected neutron powder diffraction data from MgSO4·11D2O (the deuterated analogue of meridianiite), a highly hydrated sulfate salt that is thought to be a candidate rock-forming mineral in some icy satellites of the outer solar system. Our measurements, made using the PEARL/HiPr and OSIRIS instruments at the ISIS neutron spallation source, covered the range 0.1 < P < 800 MPa and 150 < T < 280 K. The refined unit-cell volumes as a function of P and T are parameterized in the form of a Murnaghan integrated linear equation of state having a zero-pressure volume V
0 = 706.23 (8) Å3, zero-pressure bulk modulus K
0 = 19.9 (4) GPa and its first pressure derivative, K′ = 9 (1). The structure's compressibility is highly anisotropic, as expected, with the three principal directions of the unit-strain tensor having compressibilities of 9.6 × 10−3, 3.4 × 10−2 and 3.4 × 10−3 GPa−1, the most compressible direction being perpendicular to the long axis of a discrete hexadecameric water cluster, (D2O)16. At high pressure we observed two different phase transitions. First, warming of MgSO4·11D2O at 545 MPa resulted in a change in the diffraction pattern at 275 K consistent with partial (peritectic) melting; quasielastic neutron spectra collected simultaneously evince the onset of the reorientational motion of D2O molecules with characteristic time-scales of 20–30 ps, longer than those found in bulk liquid water at the same temperature and commensurate with the lifetime of solvent-separated ion pairs in aqueous MgSO4. Second, at ∼ 0.9 GPa, 240 K, MgSO4·11D2O decomposed into high-pressure water ice phase VI and MgSO4·9D2O, a recently discovered phase that has hitherto only been formed at ambient pressure by quenching small droplets of MgSO4(aq) in liquid nitrogen. The fate of the high-pressure enneahydrate on further compression and warming is not clear from the neutron diffraction data, but its occurrence indicates that it may also be a rock-forming mineral in the deep mantles of large icy satellites.
Structure, thermal expansion and incompressibility of MgSO4·9H2O, its relationship to meridianiite (MgSO4·11H2O) and possible natural occurrences
Authors: Fortes A. Dominic , Knight Kevin S. , Wood Ian G.
Published: February 2017

Since being discovered initially in mixed-cation systems, a method of forming end-member MgSO4·9H2O has been found. We have obtained powder diffraction data from protonated analogues (using X-rays) and deuterated analogues (using neutrons) of this compound over a range of temperatures and pressures. From these data we have determined the crystal structure, including all hydrogen positions, the thermal expansion over the range 9–260 K at ambient pressure, the incompressibility over the range 0–1.1 GPa at 240 K and studied the transitions to other stable and metastable phases. MgSO4·9D2O is monoclinic, space group P21/c, Z = 4, with unit-cell parameters at 9 K, a = 6.72764 (6), b = 11.91154 (9), c = 14.6424 (1) Å, β = 95.2046 (7)° and V = 1168.55 (1) Å3. The structure consists of two symmetry-inequivalent Mg(D2O)6 octahedra on sites of \bar 1 symmetry. These are directly joined by a water–water hydrogen bond to form chains of octahedra parallel with the b axis at a = 0. Three interstitial water molecules bridge the Mg(D2O)6 octahedra to the SO4
2− tetrahedral oxyanion. These tetrahedra sit at a ≃ 0.5 and are linked by two of the three interstitial water molecules in a pentagonal motif to form ribbons parallel with b. The temperature dependences of the lattice parameters from 9 to 260 K have been fitted with a modified Einstein oscillator model, which was used to obtain the coefficients of the thermal expansion tensor. The volume thermal expansion coefficient, αV, is substantially larger than that of either MgSO4·7D2O (epsomite) or MgSO4·11D2O (meridianiite), being ∼ 110 × 10−6 K−1 at 240 K. Fitting to a Murnaghan integrated linear equation of state gave a zero-pressure bulk modulus for MgSO4·9D2O at 240 K, K
0 = 19.5 (3) GPa, with the first pressure derivative of the bulk modulus, K′ = 3.8 (4). The bulk modulus is virtually identical to meridianiite and only ∼ 14% smaller than that of epsomite. Above ∼ 1 GPa at 240 K the bulk modulus begins to decrease with pressure; this elastic softening may indicate a phase transition at a pressure above ∼ 2 GPa. Synthesis of MgSO4·9H2O from cation-pure aqueous solutions requires quench-freezing of small droplets, a situation that may be relevant to spraying of MgSO4-rich cryomagmas into the surface environments of icy satellites in the outer solar system. However, serendipitously, we obtained a mixture of MgSO4·9H2O, mirabilite (Na2SO4·10H2O) and ice by simply leaving a bottle of mid-winter brine from Spotted Lake (Mg/Na ratio = 3), British Columbia, in a domestic freezer for a few hours. This suggests that MgSO4·9H2O can occur naturally – albeit on a transient basis – in certain terrestrial and extraterrestrial environments.
An unusual case of OD-allotwinning: 9,9′-(2,5-dibromo-1,4-phenylene)bis[9H-carbazole]
Authors: Kautny Paul , Schwartz Thomas , Stöger Berthold , Fröhlich Johannes
Published: February 2017

9,9′-(2,5-Dibromo-1,4-phenylene)bis[9H-carbazole] (1) crystallizes as a category I order–disorder (OD) structure composed of non-polar layers of one kind with B2/m(1)1 layer symmetry. The crystals are made up of the two polytypes with a maximum degree of order (MDO). The monoclinic MDO1 polytype (B21/d) possesses an orthorhombic B-centered lattice and appears in two orientations, which are related by reflection at (100). The orthorhombic MDO2 polytype (F2dd) has a doubled b-axis and appears in two orientations, which are related by inversion. The crystal structures of both polytypes were determined in a concurrent refinement. The MDO1:MDO2 ratio is 69:31.
Synchrotron X-ray diffuse scattering from a stable polymorphic material: terephthalic acid, C8H6O4
Authors: Goossens D. J. , Chan E. J.
Published: February 2017

Terephthalic acid (TPA, C8H6O4) is an industrially important chemical, one that shows polymorphism and disorder. Three polymorphs are known, two triclinic [(I) and (II)] and one monoclinic (III). Of the two triclinic polymorphs, (II) has been shown to be more stable in ambient conditions. This paper presents models of the local order of polymorphs (I) and (II), and compares the single-crystal diffuse scattering (SCDS) computed from the models with that observed from real crystals. TPA shows relatively weak and less-structured diffuse scattering than some other polymorphic materials, but it does appear that the SCDS is less well modelled by a purely harmonic model in polymorph (I) than in polymorph (II), according to the idea that the diffuse scattering is sensitive to anharmonicity that presages a structural phase transition. The work here verifies that displacive correlations are strong along the molecular chains and weak laterally, and that it is not necessary to allow the —COOH groups to librate to successfully model the diffuse scattering – keeping in mind that the data are from X-ray diffraction and not directly sensitive to H atoms.
Formation of co-racemic uranyl chromate constructed from chiral layers of different topology
Authors: Siidra Oleg , Nazarchuk Evgeny , Bocharov Sergey , Depmeier Wulf , Zadoya Anastasiya
Published: February 2017

Four new inorganic uranyl chromates were obtained by evaporation and hydrothermal methods: [(CH3)2NH2]2[(UO2)2(CrO4)3(H2O)](H2O) (1), K(Rb0.6K0.4)[(UO2)2(CrO4)3(H2O)](H2O)3 (2) [(CH3)3CNH3]2[(UO2)2(CrO4)3H2O] (3), [(CH3)2NH2]4[(UO2)2(CrO4)3H2O]2(H2O) (4). Their structures are based on two-dimensional chiral or achiral units with the composition [(UO2)2(CrO4)3(H2O)]2− and two types of topologies (A or/and B). The structural architecture of (4) is unique amongst all known uranyl-based structures, and unusual among hybrid organic/inorganic structures in general as it contains layers of identical composition, but of different topology. The unique structural configurations and non-centrosymmetry in (1) and (4) is governed by selective formation of hydrogen bonding rather than by the formation of hydrophobic and hydrophilic zones in the organic interlayer. It is shown that chiral architectures in uranyl systems may form from achiral building units as observed in (3) and (4). This is somewhat analogous to certain organic compounds, where achiral molecules are also able to form chiral layers. Within the concept of such an interpretation the structure of (3) can then be described as a racemate consisting of two A and A′ chiral layers. In a similar approach the structure of (4) can be interpreted as being formed by four chiral layers. Layer pairs AA′ and BB′ can then be considered as racemic pairs and the whole structure is a co-racemate built by a combination of two racemates. Two-stage formation can be suggested for (4).
A revised interpretation of the structure of (NH4)2Ge7O15 in the light of the Extended Zintl–Klemm Concept
Authors: Vegas Angel , Jenkins Harry Donald Brooke
Published: February 2017

The structure of (NH4)2Ge7O15 recently described as being a microporous material containing rings, in which GeO6 octahedra coexist with GeO4 tetrahedra, is re-examined in the light of the Extended Zintl–Klemm Concept as applied to cations in oxides. The Ge[6] atoms together with the NH4
+ groups act as true cations, transferring their 6 valence electrons to the acceptor Ge2O5 moiety, so converting it into the [Ge6O15]6−[triple-bond]3(Ψ-As2O5) ion (where Ψ refers to a pseudo-lattice) and yielding threefold connectivity. The tetrahedral Ge network shows similarities with the Sb2O3 analogue. At the same time, the Ge[6] atoms are connected to other Ge[4] atoms forming blocks that are part of a rutile-type GeO2 structure. Such an analysis shows that both substructures (the Zintl polyanion and the rutile fragments) must be satisfied simultaneously as has already been illustrated in previous articles which considered stuffed-bixbyites [Vegas et al. (2009). Acta Cryst. B65, 11–21] as well as the compound FeLiPO4 [Vegas (2011). Struct. Bond.
138, 67–91]. This new insight conforms well to previous (differential thermal analysis) DTA–TGA (thermogravimetric analysis) experiments [Cascales et al. (1998). Angew. Chem. Int. Ed. 37, 129–131], which show endothermic loss of NH3 and H2O to give rise to the metastable structure Ge7O14, which further collapses to the rutile-type GeO2 structure. We analyze the stability change in terms of ionic strength, I, and so provide a means of rationalizing the driving force behind this concept capable of explaining the atomic arrangements found in these types of crystal structures. Although the concept was formulated in 2003, later than the publication of the germanate structure, it was not used or else ignored by colleagues who solved this crystal structure.
Strategies for carbohydrate model building, refinement and validation
Authors: Agirre Jon
Published: February 2017

Sugars are the most stereochemically intricate family of biomolecules and present substantial challenges to anyone trying to understand their nomenclature, reactions or branched structures. Current crystallographic programs provide an abstraction layer allowing inexpert structural biologists to build complete protein or nucleic acid model components automatically either from scratch or with little manual intervention. This is, however, still not generally true for sugars. The need for carbohydrate-specific building and validation tools has been highlighted a number of times in the past, concomitantly with the introduction of a new generation of experimental methods that have been ramping up the production of protein–sugar complexes and glycoproteins for the past decade. While some incipient advances have been made to address these demands, correctly modelling and refining carbohydrates remains a challenge. This article will address many of the typical difficulties that a structural biologist may face when dealing with carbohydrates, with an emphasis on problem solving in the resolution range where X-ray crystallography and cryo-electron microscopy are expected to overlap in the next decade.
Maize seedling morphology and defence hormone profiles, but not herbivory tolerance, were mediated by domestication and modern breeding
Authors: Chinchilla‐Ramírez M. , Borrego E.J. , DeWitt T.J. , Kolomiets M.V. , Bernal J.S.
Published: February 2017

We addressed whether Zea seedling morphology relevant to performance, defence hormone profiles and tolerance of a phloem‐feeding, specialist herbivore were affected by two processes, plant domestication and modern breeding. Domestication effects were inferred through comparisons between Balsas teosintes (Zea mays parviglumis) and landrace maizes (Z. mays mays), and modern breeding effects through comparisons between landrace maizes and inbred maize lines. Specifically, we compared seedling forms (a composite measure of leaf length, average stem diameter, shoot wet weight, shoot dry weight, total root length, root wet weight, and root dry weight), shapes (forms scaled by seedling dry weight, a proxy for seedling size), and defence hormone profiles among Balsas teosinte and landrace and inbred line maizes, exposed or unexposed to feeding by Dalbulus maidis. Our results suggested that domestication as well as modern breeding strongly mediated both seedling form and shape. Form was more similar between landrace and inbred maize than between Balsas teosinte and landrace maize, suggesting that domestication affected seedling form more than modern breeding. In contrast, shape was more similar between Balsas teosinte and landrace maize than between landrace and inbred maizes, suggesting that modern breeding affected seedling shape more than domestication. Additionally, seedling shoot : root ratios appeared to have been mediated by domestication, but not by modern breeding. In broad terms, individual seedling structures relevant to seedling ecology in wild or managed environments, such as leaf and root lengths, and shoot and root masses, were enlarged with domestication and reduced with modern breeding. Herbivory did not affect seedling shape, but had a weak effect on form so that seedlings were slightly larger in the absence versus presence of D. maidis. Also, both domestication and modern breeding seem to have mediated seedling hormone profiles, with breeding more strongly mediating profiles than domestication. Jasmonic acid isoleucine (JA‐Ile) and salicylic acid (SA) were induced by herbivory in both teosinte and maize. The hormone profiles assays collectively suggested that domestication and modern breeding altered constitutive levels of SA, abscisic acid and JA‐related (JA‐Ile and oxo‐phytodienoic acid) hormone levels in seedlings, particularly by increasing the levels of SA and decreasing those of JA‐related hormones. Altogether, our results suggested that maize domestication and modern breeding significantly altered seedling form, shape, ecologically relevant morphological traits (e.g. leaf and root lengths, and shoot and root masses) and hormonal defences, but not tolerance of D. maidis herbivory.
Implications for future research on drivers of change and alternatives to Alcoholics Anonymous
Authors: Zemore Sarah E.
Published: February 2017

Commentary to: Is Alcoholics Anonymous religious, spiritual, neither? Findings from 25 years of mechanisms of behavior change research
Optimal split‐plot orthogonal arrays
Authors: Yang Po , Lin Chang‐Yun
Published: February 2017

It is well known that many industrial experiments have split‐plot structures. Compared to completely randomised experiments, split‐plot designs are more economical and thus have received much attention among researchers. Much work has been done for two‐level split‐plot designs. In this article, we consider split‐plot designs with factors of three, more than three, or mixed levels and with both qualitative and quantitative factors. We show that if two designs with both qualitative and quantitative factors are geometrically isomorphic, then their generalised wordlength patterns are identical. Three design scenarios are considered for optimal designs. The corresponding wordlength patterns are defined and the minimum aberration mixed‐level split‐plot designs having 18 and 36 runs are tabulated.