bluuebunny/crossref_metadata_2025 huggingface dataset:
Solution phase dynamics of the DNA repair enzyme spore photoproduct lyase as probed by H/D exchange
Authors: Ghose Shourjo , Hilmer Jonathan K. , Bothner Brian , Broderick Joan B.
Published: June 2014

Spore photoproduct lyase (SPL) catalyzes the repair of the UV lesion spore photoproduct (SP) in a reaction dependent on S‐adenosyl‐l‐methionine (SAM). We have utilized H/D exchange to show that in the presence of SAM, a significant reduction in H/D exchange is observed upon binding SPTpT or undamaged oligonucleotide, indicating a shift of 20 or 10 amide protons, respectively, from a rapidly‐exchangable state to a fully‐protected conformation. In the absence of SAM, neither the oligonucleotide nor the SPTpT produce a significant perturbation in H/D exchange, indicating SAM is a requisite binding partner. Performing the same experiments in aerobic conditions reduced the magnitude of ligand‐induced structural changes, consistent with the importance of the oxygen‐sensitive iron–sulfur cluster for SAM and substrate binding.
Genome wide functional genetics in haploid cells
Authors: Elling Ulrich , Penninger Josef M.
Published: June 2014

Some organisms such as yeast or males of social insects are haploid, i.e. they carry a single set of chromosomes, while haploidy in mammals is exclusively restricted to mature germ cells. A single copy of the genome provides the basis for genetic analyses where any recessive mutation of essential genes will show a clear phenotype due to the absence of a second gene copy. Most prominently, haploidy in yeast has been utilized for recessive genetic screens that have markedly contributed to our understanding of development, basic physiology, and disease. Somatic mammalian cells carry two copies of chromosomes (diploidy) that obscure genetic analysis. Near haploid human leukemic cells however have been developed as a high throughput screening tool. Although deemed impossible, we and others have generated mammalian haploid embryonic stem cells from parthenogenetic mouse embryos. Haploid stem cells open the possibility of combining the power of a haploid genome with pluripotency of embryonic stem cells to uncover fundamental biological processes in defined cell types at a genomic scale. Haploid genetics has thus become a powerful alternative to RNAi or CRISPR based screens.
Monitoring Daily Function in Persons With Transfemoral Amputations Using a Commercial Activity Monitor: A Feasibility Study
Authors: Albert Mark V. , Deeny Sean , McCarthy Cliodhna , Valentin Juliana , Jayaraman Arun
Published: June 2014

Objective

To assess in a feasibility study the mobility of persons with transfemoral amputations using data collected from a popular, consumer‐oriented activity monitor (Fitbit).

Design

Observational cohort study.

Setting

Research hospital outpatient evaluation.

Participants

Nine subjects with transfemoral amputations (4 women and 5 men, ages 21‐64 years) and Medicare functional assessments (K level) of K3 (n = 7), K2 (n = 1), and K4 (n = 1).

Methods

One‐week monitoring of physical activity using the Fitbit One activity monitor.

Main Outcome Measures

Daily estimates of step counts, distance walked, floors/stairs climbed, calories burned, and proprietary Fitbit activity scores. For each day, the amount of time in each of the following levels of activity was also reported: sedentary, lightly active, fairly active, and highly active.

Results

The percentage of movement time above the fairly active level had a predictable relationship to the designated K level. The average activity measures show decreased levels of activity for obese subjects (body mass index >30). Estimated step counts were highly predictive/redundant with estimated miles walked without setting individual stride lengths. Using linear regression prediction models, calorie estimates were found to be highly dependent on subject age, height, and weight, whereas the proprietary activity score was independent of all 3 demographic factors.

Conclusions

This feasibility study demonstrates that the Fitbit activity monitor estimates the activity of subjects with transfemoral amputations, producing results that correlate with their K‐level functional activity classifications. The Fitbit activity score is independent of individual variations in age, weight, and height compared with estimated calories for this small sample size. These tools may provide useful insights into prosthetic use in an at‐home environment.
Turbulent plane Couette flow at moderately high Reynolds number
Authors: Avsarkisov V. , Hoyas S. , Oberlack M. , García-Galache J. P.
Published: June 2014

A new set of numerical simulations of turbulent plane Couette flow in a large box of dimension ($\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}20\pi h,\, 2h,\, 6\pi h$) at Reynolds number $(\mathit{Re}_{\tau }) =125$, 180, 250 and 550 is described and compared with simulations at lower Reynolds numbers, Poiseuille flows and experiments. The simulations present a logarithmic near-wall layer and are used to verify and revise previously known results. It is confirmed that the fluctuation intensities in the streamwise and spanwise directions do not scale well in wall units. The scaling failure occurs both near to and away from the wall. On the contrary, the wall-normal intensity scales in inner units in the near-wall region and in outer units in the core region. The spectral ridge found by Hoyas & Jiménez (Phys. Fluids, vol. 18, 2003, 011702) for the turbulent Poiseuille flow can also be seen in the present flow. Away from the wall, very large-scale motions are found spanning through all the length of the channel. The statistics of these simulations can be downloaded from the webpage of the Chair of Fluid Dynamics.
The Ghost in the House: Women, Race, and Domesticity in South Africa
Authors: Baderoon Gabeba
Published: June 2014

In South Africa, the house is a haunted place. Apartheid’s separate publics also required separate private lives and separate leisures in which to practice ways of living apartheid’s ideological partitions into reality. This essay analyzes the compulsive interest in black domesticity that has characterized South Africa since the colonial period and shows that domestic labor in white homes has historically shaped the entry of black women into public space in South Africa. In fact, so strong is the latter association that theDictionary of South African English on Historical Principlesreveals that in South African English the wordmaiddenotes both “black woman” and “servant.” This conflation has generated fraught relations of domesticity, race, and subjectivity in South Africa. Contemporary art about domestic labor by Zanele Muholi and Mary Sibande engages with this history. In their art, the house is a place of silences, ghosts, and secrets. Precursors to these recent works can be found in fiction, including Sindiwe Magona’s short stories about domestic workers in her collectionLiving, Loving and Lying Awake at Night(1994) and Zoë Wicomb’s novelPlaying in the Light(2006), in which a woman passing for white allows her mother into her house only under the pretense that she is a family servant. Muholi and Sibande have engaged the legacy of black women in white households by revisiting the ghosts of the house through performance, sculpture, and photography. Both were inspired by the intimate reality of their mothers’ experiences as domestic servants, and in both cases the artist’s body is central to the pieces, through installations based on body casts, performance, embodied memories, and the themes of haunted absences, abandonment, and longing.
Isotopic tracing of sediment components assimilated by epibiontic juveniles ofHolothuria scabra(Holothuroidea)
Authors: Plotieau T. , Lepoint G. , Lavitra T. , Eeckhaut I.
Published: June 2014

DespiteHolothuria scabra's wide distribution and status as one of the best candidates for sustaining the development of tropical sea cucumber aquaculture, very few data are available regarding the organic fraction it assimilates in practice. In this paper we report experimental results whereH. scabra's diet was supplemented with various15N-labelled organic fractions of sediment. We used juveniles weighing between 38 and 88 mg at the beginning of the experiment (~2 cm long and 30 days old). Their growth was measured over a four-week period and their15N composition recorded. The results showed thatH. scabrajuveniles assimilated all added organic components from both dissolved and particulate fractions of the sediment. Bacteria seem to be an important food source for juveniles, even more so than microphytobenthos (diatoms).
The Medicalization of Love
Authors: EARP BRIAN D. , SANDBERG ANDERS , SAVULESCU JULIAN
Published: June 2014

Pharmaceuticals or other emerging technologies could be used to enhance (or diminish) feelings of lust, attraction, and attachment in adult romantic partnerships. Although such interventions could conceivably be used to promote individual (and couple) well-being, their widespread development and/or adoption might lead to the ‘medicalization’ of human love and heartache—for some, a source of a serious concern. In this essay, we argue that the medicalization of love need not necessarily be problematic, on balance, but could plausibly be expected to have either good or bad consequences depending upon how it unfolds. By anticipating some of the specific ways in which these technologies could yield unwanted outcomes, bioethicists and others can help to direct the course of love’s medicalization—should it happen to occur—more toward the ‘good’ side than the ‘bad.’
On the strategic use of border tax adjustments as a second-best climate policy measure
Authors: Mason Charles F. , Barbier Edward B. , Umanskaya Victoria I.
Published: June 2014

We investigate the interaction between a developed country that imports a carbon-intensive product, such as electricity, and a transitioning economy that exports the product. Production of the good generates a transboundary externality related to climate change; if this externality is priced improperly, the application of a feed-in tariff or border tax adjustment can provide an indirect policy instrument. We analyze the application of such a measure in a stark model where the importing country cares about climate-related damages while the exporting country does not; this can be viewed as reflecting a scenario where the (developed) importing country is more concerned about climate change than is the (transitioning) exporting economy. Because climate change will occur over a long time frame, the problem is dynamic. In this modeling context, we describe the manner in which the (second-best) tariff-cum-border tax adjustment relates to the carbon stock.
Field validation of food outlet databases: the Latino food environment in North Carolina, USA
Authors: Rummo Pasquale E , Gordon-Larsen Penny , Albrecht Sandra S
Published: June 2014

Objective

Obtaining valid, reliable measures of food environments that serve Latino communities is important for understanding barriers to healthy eating in this at-risk population.

Design

The primary aim of the study was to examine agreement between retail food outlet data from two commercial databases, Nielsen TDLinx (TDLinx) for food stores and Dun & Bradstreet (D&B) for food stores and restaurants, relative to field observations of food stores and restaurants in thirty-one census tracts in Durham County, NC, USA. We also examined differences by proportion of Hispanic population (</≥23·4 % Hispanic population) in the census tract and for outlets classified in the field as ‘Latino’ on the basis of signage and use of Spanish language.

Setting

One hundred and seventy-four food stores and 337 restaurants in Durham County, NC, USA.

Results

We found that overall sensitivity of food store listings in TDLinx was higher (64 %) than listings in D&B (55 %). Twenty-five food stores were characterized by auditors as Latino food stores, with 20 % identified in TDLinx, 52 % in D&B and 56 % in both sources. Overall sensitivity of restaurants (68 %) was higher than sensitivity of Latino restaurants (38 %) listed in D&B. Sensitivity did not differ substantially by Hispanic composition of neighbourhoods.

Conclusions

Our findings suggest that while TDLinx and D&B commercial data sources perform well for total food stores, they perform less well in identifying small and independent food outlets, including many Latino food stores and restaurants.
“MyBusiness is to Sing”: Emily Dickinson's Musical Borrowings
Authors: BOZIWICK GEORGE
Published: June 2014

The daily musical activities of poet Emily Dickinson (1830–86)—home performances at the piano, collecting sheet music, and attending concerts—provided a vital and necessary backdrop for her emerging artistic persona. Dickinson's active musical life reveals a great deal about the cultural offerings available to a woman of her time, place, and class. Moreover, her encounters with the music-making of the Dickinson family servants and the New England hymn tradition encouraged artistic borrowings and boundary crossings that had a deep and continuing influence on her writing. Through her engagement with music, Dickinson was able to fashion an identity served by musical longings, one that would ultimately serve a vital role in the formation of her unique poetic voice.
High prevalence of biofilm synergy among bacterial soil isolates in cocultures indicates bacterial interspecific cooperation
Authors: Ren Dawei , Madsen Jonas S , Sørensen Søren J , Burmølle Mette
Published: June 2014

Biofilms that form on roots, litter and soil particles typically contain multiple bacterial species. Currently, little is known about multispecies biofilm interactions and few studies have been based on environmental isolates. Here, the prevalence of synergistic effects in biofilm formation among seven different soil isolates, cocultured in combinations of four species, was investigated. We observed greater biofilm biomass production in 63% of the four-species culture combinations tested than in biofilm formed by single-species cultures, demonstrating a high prevalence of synergism in multispecies biofilm formation. One four-species consortium, composed of Stenotrophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans and Paenibacillus amylolyticus, exhibited strong synergy in biofilm formation and was selected for further study. Of the four strains, X. retroflexus was the only one capable of forming abundant biofilm in isolation, under the in vitro conditions investigated. In accordance, strain-specific quantitative PCR revealed that X. retroflexus was predominant within the four-species consortium (>97% of total biofilm cell number). Despite low relative abundance of all the remaining strains, all were indispensable for the strong synergistic effect to occur within the four-species biofilm. Moreover, absolute individual strain cell numbers were significantly enhanced when compared with those of single-species biofilms, indicating that all the individual strains benefit from inclusion in the multispecies community. Our results show a high prevalence of synergy in biofilm formation in multispecies consortia isolated from a natural bacterial habitat and suggest that interspecific cooperation occurs.
Low energy structural dynamics and constrained libration of Li(NH3)4, the lowest melting point metal
Authors: Seel A. G. , Zurek E. , Ramirez-Cuesta A. J. , Ryan K. R. , Lodge M. T. J. , Edwards P. P.
Published: June 2014

The structural dynamics of Li(NH3)4, the lowest melting point metal, are reported in the range of phonon and low-energy internal distortions. Hindrance of NH3libration in the solid are characterisedviainelastic neutron scattering and computational modeling.
Polarization dressed multi-order fluorescence of Pr3+:Y2SiO5
Authors: Wang Ruimin , Lei Chengjun , Li Changbiao , Lan Huayan , Zheng Huaibin , Xiao Min , Zhang Yanpeng
Published: June 2014

We report polarization dressed second-, fourth- and sixth-order fluorescence processes in a Pr3+:Y2SiO5 crystal.
Kinetic model facilitates analysis of fibrin generation and its modulation by clotting factors: implications for hemostasis-enhancing therapies
Authors: Mitrophanov Alexander Y. , Wolberg Alisa S. , Reifman Jaques
Published: June 2014

We developed a computational model that accounts for essential kinetic features of thrombin generation, fibrin formation, and fibrinolysis in diversein vitrosystems. We applied it to characterize strategies to improve hemostasis.
Synthesis of donor–acceptor conjugated polymers based on benzo[1,2-b:4,5-b′]dithiophene and 2,1,3-benzothiadiazole via direct arylation polycondensation: towards efficient C–H activation in nonpolar solvents
Authors: Wang Xiaochen , Wang Mingfeng
Published: June 2014

1,2-Dimethylbenzene, as a nonpolar high boiling point solvent, has been discovered to be a superior medium to perform direct-arylation polymerization.
Understanding the photothermal effect of gold nanostars and nanorods for biomedical applications
Authors: Wang Xiaocui , Li Guohua , Ding Yu , Sun Shuqing
Published: June 2014

Photothermal properties of GNSs and GNRs are compared both experimentally and theoretically, and results show that GNSs exhibit a higher molar heating rate than GNRs.
Improved amorphous/crystalline silicon interface passivation with two-step intrinsic layers
Authors: Jiang Yuanjian , Zhang Xiao-dan , Wang Fengyou , Wei Changchun , Zhao Ying
Published: June 2014

The implied Voc value of the sample obtained using the two-step i-layers process was much higher than that obtained using the traditional one step i-layer process.
Facile fabrication of CuO nanowire modified Cu electrode for non-enzymatic glucose detection with enhanced sensitivity
Authors: Ni Pengjuan , Sun Yujing , Shi Yan , Dai Haichao , Hu Jingting , Wang Yilin , Li Zhuang
Published: June 2014

A facile method to fabricate a non-enzymatic glucose sensor based on CuO nanowires is developed.
Sulfanilic acid-functionalized silica-coated magnetite nanoparticles as an efficient, reusable and magnetically separable catalyst for the solvent-free synthesis of 1-amido- and 1-aminoalkyl-2-naphthols
Authors: Moghanian H. , Mobinikhaledi A. , Blackman A. G. , Sarough-Farahani E.
Published: June 2014

Sulfanilic acid-functionalized silica-coated magnetite nanoparticles as an efficient, reusable and magnetically separable catalyst for the solvent-free synthesis of 1-amido- and 1-aminoalkyl-2-naphthols.
Hydrogen-bonding strategy for constructing pH-sensitive core–shell micelles with hydrophilic polymer as the shell and hydrophobic drug as the core
Authors: Wang Wei , Yang Hong , Kong Xiangqi , Ye Zhao , Yin Yihua , Zhang Xueqiong , He Guanghua , Xu Peihu , Zheng Hua
Published: June 2014

pH-sensitive micelles with hydrophilic polymer as the shell and hydrophobic drug as the core.
Light alkane oxidation using catalysts prepared by chemical vapour impregnation: tuning alcohol selectivity through catalyst pre-treatment
Authors: Forde Michael M. , Armstrong Robert D. , McVicker Rebecca , Wells Peter P. , Dimitratos Nikolaos , He Qian , Lu Li , Jenkins Robert L. , Hammond Ceri , Lopez-Sanchez Jose Antonio , Kiely Christopher J. , Hutchings Graham J.
Published: June 2014

Heat treating Fe/ZSM-5 under hydrogen leads to high dispersion of Fe species and higher alcohol selectivity in the oxidation of alkanes, as compared to oxygen treated catalysts.
Corrosion of molybdate intercalated hydrotalcite coating on AZ31 Mg alloy
Authors: Zeng Rong-Chang , Liu Zhen-Guo , Zhang Fen , Li Shuo-Qi , Cui Hong-Zhi , Han En-Hou
Published: June 2014

A nanosized smart coating with ion exchange and self-healing ability was synthesized, and the inhibition mechanism of the coating was proposed.
Anti-frost coatings containing carbon nanotube composite with reliable thermal cyclic property
Authors: Sohn Yoonchul , Kim Dongouk , Lee Sangeui , Yin Mingming , Song Jae Yong , Hwang Wootaek , Park Sunghoon , Kim Hajin , Ko Youngchul , Han Intaek
Published: June 2014

After repeated thermal cycling, MWNT–silicone superhydrophobic coatings retain their superhydrophobic nature with no mechanical degradation through a large amount of stress relaxation.
Hierarchical NiCoO2 nanosheets supported on amorphous carbon nanotubes for high-capacity lithium-ion batteries with a long cycle life
Authors: Xu Xin , Dong Bitao , Ding Shujiang , Xiao Chunhui , Yu Demei
Published: June 2014

NiCoO2 nanosheets@amorphous CNT composites show enhanced cycling performance and rate capability as anode materials for lithium-ion batteries.
Hollow carbon nanofiber as a stabilizer for in situ TiO2/VO2 co-impregnation with high rate performance and ultra-long cycling life as lithium-ion battery anode
Authors: Wang Xinran , Zheng Shili , Wang Shaona , Zhang Yi , Du Hao
Published: June 2014

High anodic power rate and ultra-long cycling stability were achieved by co-encapsulation of TiO2/VO2 into hollow carbon nanofibers.
Drug loaded phosphate glass/hydroxyapatite nanocomposite for orthopedic applications
Authors: Govindan R. , Girija E. K.
Published: June 2014

A cylindrical shaped gentamicin sulfate (GS) loaded phosphate glass/hydroxyapatite (PG/HA) nanocomposite with sustained release behavior has been developed for osteomyelitis.
Graphene–carbonyl iron cross-linked composites with excellent electromagnetic wave absorption properties
Authors: Zhu Zetao , Sun Xin , Xue Hairong , Guo Hu , Fan Xiaoli , Pan Xuchen , He Jianping
Published: June 2014

A carbon-bridge effect was adopted to explain the electromagnetic wave absorbing property related to the cross-linked framework structure of RGO–SCI composites.
Role of the potassium channel KCa3.1 in diabetic nephropathy
Authors: Huang Chunling , Pollock Carol A. , Chen Xin-Ming
Published: June 2014

There is an urgent need to identify novel interventions for mitigating the progression of diabetic nephropathy. Diabetic nephropathy is characterized by progressive renal fibrosis, in which tubulointerstitial fibrosis has been shown to be the final common pathway of all forms of chronic progressive renal disease, including diabetic nephropathy. Therefore targeting the possible mechanisms that drive this process may provide novel therapeutics which allow the prevention and potentially retardation of the functional decline in diabetic nephropathy. Recently, the Ca2+-activated K+ channel KCa3.1 (KCa3.1) has been suggested as a potential therapeutic target for nephropathy, based on its ability to regulate Ca2+ entry into cells and modulate Ca2+-signalling processes. In the present review, we focus on the physiological role of KCa3.1 in those cells involved in the tubulointerstitial fibrosis, including proximal tubular cells, fibroblasts, inflammatory cells (T-cells and macrophages) and endothelial cells. Collectively these studies support further investigation into KCa3.1 as a therapeutic target in diabetic nephropathy.
Service design in electric vehicle sharing: evidence from Italy
Authors: Arena Marika , Azzone Giovanni , Colorni Alberto , Conte Antonio , Luè Alessandro , Nocerino Roberto
Published: June 2014

In recent years, the issue of vehicle road sharing has attracted growing attention from both researchers and operators, as a potential instrument to improve the sustainability of urban mobility or transport systems. Beside the general concept, different operational models, managerial and technological solutions have been developed, leading to a high diversification of possible vehicle sharing configurations. This heterogeneity entails a considerable complexity of the service design phase, though few academic contributions tackled this specific problem and most of the papers focused on the dynamics of adoption and use of the service itself. To fill such a gap, this paper aims to present the approach followed in the design phase of an electric vehicle sharing service for the city of Milano. The methodology adopted in this work is based on the idea that a vehicle sharing service needs to be configured to answer to specific mobility needs coherently with the characteristics of target customers. To explain this idea the methodology was articulated into four steps, which are reported in detail in this study: (i) mapping of mobility profiles and service performances, (ii) competitive analysis, (iii) development of the service configurations and (iv) development of the evaluation model.
Genetic algorithm applied to beamspace‐multiple‐input and multiple‐output single‐radio frequency front‐end reconfigurable transceivers
Authors: Thomatos Evangelos D. , Vasileiou Panagiotis N. , Kanatas Athanasios G.
Published: June 2014

The multiple‐input and multiple‐output (MIMO) capabilities of electronically steerable passive array radiator (ESPAR) antennas in the beamspace (BS) domain have designated them a strong candidate for BS‐MIMO implementations using transceivers with a single‐radio frequency front‐end. The core functionality of the ESPAR is based on the multiplexing of information symbols in the BS domain, using orthogonal basis patterns. The radiated pattern of the antenna is produced as the linear combination of the basis patterns weighted by the information symbols to be transmitted. The adequate approximation of the desired radiation pattern produced by the antenna is of high importance in order to retain the orthogonality between the basis patterns and the corresponding information streams. The beamforming in ESPAR antennas is achieved by applying the appropriate set of loads at the parasitic elements. Nevertheless, because of the non‐linear relationship between the radiation pattern and the loads of antenna elements, the calculation of these loads is not a trivial task. This paper presents a novel genetic algorithm (GA), designed to calculate the loading values of the parasitic elements of an ESPAR used by BS‐MIMO systems in realistic channel environments. The performance evaluation of the proposed GA reveals a robust and valuable optimisation tool even for demanding applications.
Non‐linear controller approach for an autonomous battery‐assisted photovoltaic system feeding an AC load with a non‐linear component
Authors: Khayamy Mehdy , Ojo Olorunfemi , Sota Eseme
Published: June 2014

The conventional controller design of the autonomous photovoltaic (PV) energy system feeding a load is usually based on a dual‐loop cascade controller structure. The controllers are designed based on the small signal equations of the non‐linear system. However, most of the elements comprising the energy system are non‐linear in nature such that controllers based on small signal models are not effective in all operability regions. Since the PV‐battery‐assisted energy system has four inputs and five controlled outputs, it is a non‐square mult‐input–multi‐output system as well. To consider the non‐linear behaviour of the system, the concept of feedback linearisation control algorithm is used which provides satisfactory performance, ensures input–output decoupled control on each of the outputs and gives the opportunity to achieve any level of dynamic performance through appropriate locations of the closed‐loop eigenvalues and zeros. Different modes of operation of the autonomous, battery‐assisted PV system and their controls are investigated and their boundaries of operation are determined. The proposed control algorithm is programmed to operate in all the modes of operation and it is shown that for various load demands, solar irradiation levels and the status of the battery, the control system set forth faithfully follows the reference points. These assertions are validated with computer simulation results.
Dipolar correlations in structured solvents under nanoconfinement
Authors: Buyukdagli Sahin , Blossey Ralf
Published: June 2014

We study electrostatic correlations in structured solvents confined to nanoscale systems. We derive variational equations of Netz-Orland type for a model liquid composed of finite size dipoles. These equations are solved for both dilute solvents and solvents at physiological concentrations in a slit nanopore geometry. Correlation effects are of major importance for the dielectric reduction and anisotropy of the solvent resulting from dipole image interactions and also lead to a reduction of van der Waals attractions between low dielectric bodies. Finally, by comparison with other recently developed self-consistent theories and experiments, we scrutinize the effect of solvent-membrane interactions on the differential capacitance of the charged liquid in contact with low dielectric substrates. The interfacial solvent depletion driven by solvent-image interactions plays the major role in the observed low values of the experimental capacitance data, while non-locality associated with the extended charge structure of solvent molecules only brings a minor contribution.
Theoretical study of Raman chirped adiabatic passage by X-ray absorption spectroscopy: Highly excited electronic states and rotational effects
Authors: Engin Selma , Sisourat Nicolas , Selles Patricia , Taïeb Richard , Carniato Stéphane
Published: June 2014

Raman Chirped Adiabatic Passage (RCAP) is an efficient method to climb the vibrational ladder of molecules. It was shown on the example of fixed-in-space HCl molecule that selective vibrational excitation can thus be achieved by RCAP and that population transfer can be followed by X-ray Photoelectron spectroscopy [S. Engin, N. Sisourat, P. Selles, R. Taïeb, and S. Carniato, Chem. Phys. Lett. 535, 192–195 (2012)]. Here, in a more detailed analysis of the process, we investigate the effects of highly excited electronic states and of molecular rotation on the efficiency of RCAP. Furthermore, we propose an alternative spectroscopic way to monitor the transfer by means of X-ray absorption spectra.
Dynamics of heavy-Rydberg ion-pair formation in K(14p,20p)-SF6, CCl4 collisions
Authors: Wang C. H. , Kelley M. , Buathong S. , Dunning F. B.
Published: June 2014

The dynamics of formation of heavy-Rydberg ion-pair states through electron transfer in K(np)-SF6, CCl4 collisions is examined by measuring the velocity, angular, and binding energy distributions of the product ion pairs. The results are analyzed with the aid of a Monte Carlo collision code that models both the initial electron capture and the subsequent evolution of the ion pairs. The model simulations are in good agreement with the experimental data and highlight the factors such as Rydberg atom size, the kinetic energy of relative motion of the Rydberg atom and target particle, and (in the case of attaching targets that dissociate) the energetics of dissociation that can be used to control the properties of the product ion-pair states.
Hole doping dependence of critical current density in YBa2Cu3O7−δ conductors
Authors: Talantsev E. F. , Strickland N. M. , Wimbush S. C. , Storey J. G. , Tallon J. L. , Long N. J.
Published: June 2014

One of the central themes in cuprate superconductivity is the evolution of the electronic properties with the charge carrier concentration, p, expressed as the number of holes per Cu ion in the CuO2 planes. In YBa2Cu3O7−δ (YBCO), p is well known to vary with oxygen content (δ) and with substitution of Ca2+ for Y3+. In this Letter, we show that p also varies with the fraction of Cu–O “chain layer” stacking faults. The resulting parabolic variation in the superconducting transition temperature (Tc) is also well known; however, the effect on the critical current density (Jc) is less well explored. We show that the self-field Jc follows a common trend for all these hole doping methods, rising to a sharp peak on the slightly overdoped side of the Tc(p) parabola. In contrast, the in-field Jc anisotropy at high temperatures and low fields is determined solely by the stacking-fault fraction, not by hole doping, such that a sample free from stacking faults tends towards an isotropic Jc. These results serve to emphasize the role of sample microstructure in determining Jc in-field anisotropy.
100 eV electron temperatures in the Maryland centrifugal experiment observed using electron Bernstein emission
Authors: Reid R. R. , Romero-Talamás C. A. , Young W. C. , Ellis R. F. , Hassam A. B.
Published: June 2014

Thermal electron Bernstein emission has been observed at the second harmonic of the electron cyclotron frequency at the mid-plane of the Maryland Centrifugal eXperiment. The emission is received in the X-mode polarization and coupled to the Bernstein wave by the B-X mode conversion process. The average B-X coupling efficiency is approximately 20%. The observed emission indicates thermal electron temperatures an excess of 100 eV in the core of the rotating plasma. The measured electron temperature is consistent with recent ion temperature measurements and indicates that the total energy confinement time exceeds 500 μs.
Low-voltage-operation avalanche photodiode based on n-gallium oxide/p-crystalline selenium heterojunction
Authors: Imura S. , Kikuchi K. , Miyakawa K. , Ohtake H. , Kubota M.
Published: June 2014

In this study, we demonstrate the avalanche multiplication phenomenon in a crystalline-selenium (c-Se)-based heterojunction photodiode. The carrier injection from an external electrode, which is considered to be the major factor contributing to dark current at a high electric field, was significantly decreased by employing a thin n-type Ga2O3 layer with a high hole-injection barrier. The fabricated Ga2O3/c-Se diode exhibited extremely high external quantum efficiency of over 100% in the short-wavelength region at a relatively low reverse-bias voltage of ∼20 V. Furthermore, Sn-doping of the Ga2O3 layer increases the carrier concentration; hence, the resulting device has a lower threshold voltage for avalanche multiplication.
Isolation of cells for selective treatment and analysis using a magnetic microfluidic chip
Authors: Yassine O. , Gooneratne C. P. , Abu Smara D. , Li F. , Mohammed H. , Merzaban J. , Kosel J.
Published: June 2014

This study describes the development and testing of a magnetic microfluidic chip (MMC) for trapping and isolating cells tagged with superparamagnetic beads (SPBs) in a microfluidic environment for selective treatment and analysis. The trapping and isolation are done in two separate steps; first, the trapping of the tagged cells in a main channel is achieved by soft ferromagnetic disks and second, the transportation of the cells into side chambers for isolation is executed by tapered conductive paths made of Gold (Au). Numerical simulations were performed to analyze the magnetic flux and force distributions of the disks and conducting paths, for trapping and transporting SPBs. The MMC was fabricated using standard microfabrication processes. Experiments were performed with E. coli (K12 strand) tagged with 2.8 μm SPBs. The results showed that E. coli can be separated from a sample solution by trapping them at the disk sites, and then isolated into chambers by transporting them along the tapered conducting paths. Once the E. coli was trapped inside the side chambers, two selective treatments were performed. In one chamber, a solution with minimal nutrition content was added and, in another chamber, a solution with essential nutrition was added. The results showed that the growth of bacteria cultured in the second chamber containing nutrient was significantly higher, demonstrating that the E. coli was not affected by the magnetically driven transportation and the feasibility of performing different treatments on selectively isolated cells on a single microfluidic platform.
Effect of deposition temperature on electron-beam evaporated polycrystalline silicon thin-film and crystallized by diode laser
Authors: Yun J. , Varlamov S. , Huang J. , Kim K. , Green M. A.
Published: June 2014

The effects of the deposition temperature on the microstructure, crystallographic orientation, and electrical properties of a 10-μm thick evaporated Si thin-film deposited on glass and crystallized using a diode laser, are investigated. The crystallization of the Si thin-film is initiated at a deposition temperature between 450 and 550 °C, and the predominant (110) orientation in the normal direction is found. Pole figure maps confirm that all films have a fiber texture and that it becomes stronger with increasing deposition temperature. Diode laser crystallization is performed, resulting in the formation of lateral grains along the laser scan direction. The laser power required to form lateral grains is higher in case of films deposited below 450 °C for all scan speeds. Pole figure maps show 75% occupancies of the (110) orientation in the normal direction when the laser crystallized film is deposited above 550 °C. A higher density of grain boundaries is obtained when the laser crystallized film is deposited below 450 °C, which limits the solar cell performance by n = 2 recombination, and a performance degradation is expected due to severe shunting.
The structural and in-plane dielectric/ferroelectric properties of the epitaxial (Ba, Sr)(Zr, Ti)O3 thin films
Authors: Chan N. Y. , Wang D. Y. , Wang Y. , Dai J. Y. , Chan H. L. W.
Published: June 2014

Epitaxial (Ba1-xSrx)(Zr0.1Ti0.9)O3 (BSZT, x = 0 – 0.45) thin films were deposited on (LaAlO3)0.3(Sr2AlTaO6)0.35 (LSAT) substrates by pulsed laser deposition. The experimental results demonstrate that the structural, dielectric, and ferroelectric properties of the BSZT thin films were greatly dependent on the strontium content. The BSZT thin films transformed from tetragonal to cubic phase when x ≥ 0.35 at room temperature. The Curie temperature and room-temperature remnant polarization decrease with increasing strontium concentration. The optimal dielectric properties were found in (Ba0.55Sr0.45)(Zr0.1Ti0.9)O3 thin films which is in paraelectric state, having tunability of 47% and loss tangent of 0.0338 under an electric field of 20 MV/m at 1 MHz. This suggests that BSZT thin film is a promising candidate for tunable microwave device applications.
Waltzing of a helium pair in tungsten: Migration barrier and trajectory revealed from first-principles
Authors: Niu J. G. , Zhan Q. , Geng W. T.
Published: June 2014

Despite well documented first-principles theoretical determination of the low migration energy (0.06 eV) of a single He in tungsten, fully quantum mechanical calculations on the migration of a He pair still present a challenge due to the complexity of its trajectory. By identifying the six most stable configurations of the He pair in W and decomposing its motion into rotational, translational, and rotational-translational routines, we are able to determine its migration barrier and trajectory. Our density functional theory calculations demonstrate a He pair has three modes of motion: a close or open circular two-dimensional motion in (100) plane with an energy barrier of 0.30 eV, a snaking motion along [001] direction with a barrier of 0.30 eV, and a twisted-ladder motion along [010] direction with the two He swinging in the plane (100) and a barrier of 0.31 eV. The graceful associative movements of a He pair are related to the chemical-bonding-like He-He interaction being much stronger than its migration barrier in W. The excellent agreement with available experimental measurements (0.24–0.32 eV) on He migration makes our first-principles result a solid input to obtain accurate He-W interatomic potentials in molecular dynamics simulations.
Organic chemicals jeopardize the health of freshwater ecosystems on the continental scale
Authors: Malaj Egina , von der Ohe Peter C. , Grote Matthias , Kühne Ralph , Mondy Cédric P. , Usseglio-Polatera Philippe , Brack Werner , Schäfer Ralf B.
Published: June 2014

Significance

Protection of freshwater ecosystems from organic pollutants is important to preserve biodiversity and the goods they provide to society, such as clean drinking water and recreation. Organic chemicals have been shown to adversely impact freshwater ecosystems in local and regional studies. Nevertheless, due to paucity of studies on larger spatial scales, it remains unknown how widespread the risk from organic chemicals is. For the first time, to our knowledge, we provide strong evidence that chemicals threaten the ecological integrity and consequently the biodiversity of almost half of the water bodies on a continental scale, based on the analysis of governmental monitoring data from 4,000 European sites. Due to limitations associated with the monitoring programs, our results are likely to underestimate the actual risks.
RNF144A, an E3 ubiquitin ligase for DNA-PKcs, promotes apoptosis during DNA damage
Authors: Ho Shiuh-Rong , Mahanic Christina S. , Lee Yu-Ju , Lin Weei-Chin
Published: June 2014

Significance

In response to DNA damage, a proper balance between DNA repair and apoptosis is very important for genomic integrity. DNA-dependent protein kinase, catalytic subunit (DNA-PKcs) plays a key role in DNA repair. Many reports also indicate a prosurvival function for cytosolic DNA-PKcs. However, how this prosurvival activity of DNA-PKcs is regulated remains unknown. We identify Ring Finger protein 144A (RNF144A) as the first E3 ubiquitin ligase for cytosolic DNA-PKcs. RNF144A is induced in a p53-dependent manner during DNA damage and targets cytosolic DNA-PKcs for ubiquitination and degradation. The regulation of DNA-PKcs by RNF144A is important for proper apoptotic response during DNA damage, suggesting a tumor suppressor function for RNF144A.
Recapitulation of the forward nuclear auxin response pathway in yeast
Authors: Pierre-Jerome Edith , Jang Seunghee S. , Havens Kyle A. , Nemhauser Jennifer L. , Klavins Eric
Published: June 2014

Significance

Auxin is a simple small molecule, yet it elicits an enormous variety of responses. How a single molecule can encode such diverse and context-specific information is a long-standing question. One hypothesis is that variation in auxin response components generates diversity in local auxin responses. To test this, we transplanted the forward nuclear auxin signal transduction pathway from plants into yeast. We found that auxin circuit composition can tune the dynamic response, and we identified which properties of auxin response components had the largest impact on circuit performance. Reconstitution of eukaryotic pathways in novel contexts can inform our understanding of the pathways themselves and can generate tools for engineering novel cellular behaviors.
Targeted placental deletion of OGT recapitulates the prenatal stress phenotype including hypothalamic mitochondrial dysfunction
Authors: Howerton Christopher L. , Bale Tracy L.
Published: June 2014

Significance

Early prenatal stress (EPS), a key risk factor for neurodevelopmental disorders, produces a marked reduction in
O
-GlcNAc transferase (OGT) in male placental tissue. In our current work, we determined that a targeted reduction of placental OGT recapitulates key features of EPS, including hypothalamic–pituitary–adrenal stress axis dysregulation, reduced postpubertal growth, and hypothalamic mitochondrial dysfunction. These results confirm that OGT serves as a key placental biomarker and functions as an important mediator of the maternal changes occurring in response to stress.
Regulation of germinal center responses and B-cell memory by the chromatin modifier MOZ
Authors: Good-Jacobson Kim L. , Chen Yunshun , Voss Anne K. , Smyth Gordon K. , Thomas Tim , Tarlinton David
Published: June 2014

Significance

Understanding the intrinsic mechanisms underlying formation of humoral memory during infection and the ability of the humoral memory population to persist for long periods of time is important for identifying potential targets for improving the efficacy of vaccines. Here we demonstrate that the chromatin modifier MOZ regulates B-cell memory formation, controlling memory compartment composition. This activity of MOZ is B cell-intrinsic and is required for establishing the germinal center gene expression program. IgM memory B cells have been implicated in maintaining the memory B-cell population over time, whereas isotype-switched memory B cells rapidly differentiate into plasmablasts upon secondary infection. Therefore, identifying potential chromatin changes that may induce differentiation into one subset over another makes MOZ a viable target for clinical translation.
Cooperative binding of the outer arm-docking complex underlies the regular arrangement of outer arm dynein in the axoneme
Authors: Owa Mikito , Furuta Akane , Usukura Jiro , Arisaka Fumio , King Stephen M. , Witman George B. , Kamiya Ritsu , Wakabayashi Ken-ichi
Published: June 2014

Significance

In eukaryotic cilia and flagella, outer arm dyneins (OADs) are bound to axonemal doublet microtubules every 24 nm; however, how this regular arrangement is produced remains unknown. To approach this problem, we studied the properties of the OAD-docking complex (ODA-DC), a three-subunit complex that functions as the OAD-docking site on the doublet. Using recombinant ODA-DC, we found that the ODA-DC has an ∼24-nm-long ellipsoidal shape and cooperatively binds to the axoneme in an end-to-end manner. These and other results indicate that cooperative association of the ODA-DC underlies the periodic OAD arrangement at specific positions on the doublets. These findings provide insight into how the regular axonemal repeat structure is produced.
Centrosomes are autocatalytic droplets of pericentriolar material organized by centrioles
Authors: Zwicker David , Decker Markus , Jaensch Steffen , Hyman Anthony A. , Jülicher Frank
Published: June 2014

Significance

How cells position their proteins is still an open question. Here, we propose a physical description of centrosomes, which are membraneless organelles involved in cell division. In our model, centrosome material occurs in a soluble form and a form that tends to form droplets by phase separation. We find that an autocatalytic chemical transition between these forms quantitatively accounts for our experimental data. Importantly, a catalytic activity of the centrioles, which are located inside centrosomes, can control centrosome nucleation and suppress Ostwald ripening to allow for two equal-sized centrosomes to coexist in the cell. Consequently, our example shows how the combination of chemical reactions and phase separation can be used to control the formation of liquid-like compartments in cells.
Evolutionarily conserved transcription factor Apontic controls the G1/S progression by inducing
cyclin E
during eye development
Authors: Liu Qing-Xin , Wang Xian-Feng , Ikeo Kazuho , Hirose Susumu , Gehring Walter J. , Gojobori Takashi
Published: June 2014

Significance

Cell differentiation is a critical point for eye development. Identification of genes for cell differentiation is critical for understanding the mechanism of eye formation and its evolution. Here, we show that an evolutionarily conserved transcription factor, Apt, regulates the G1-to-S phase transition by inducing
cyclin E
during eye development. We identify a pathway crucial for eye development, governed by a mechanism in which Cyclin E promotes the G1-to-S phase transition when regulated by Apt. One round of DNA replication before the onset of differentiation may be important to change epigenetic states from cell proliferation to development.
China’s rise as a major contributor to science and technology
Authors: Xie Yu , Zhang Chunni , Lai Qing
Published: June 2014

Significance

New data reveal that in the past three decades, China has become a major contributor to science and technology. Four factors favor China’s continuing rise in science: a large population and human capital base, a labor market favoring academic meritocracy, a large diaspora of Chinese-origin scientists, and a centralized government willing to invest in science. These factors may serve as an example to other nations aspiring to advance their standing in science. However, China’s science also faces potential difficulties due to political interference and scientific fraud.