Profound Dependence Research Articles

Solvent effects on triplet-triplet annihilation upconversion kinetics of perylene with a Bodipy-phenyl-C60 photosensitizer.

The solvent effect usually plays an important role in triplet-triplet annihilation (TTA) upconversion processes. In this work, we have studied the TTA upconversion kinetics of perylene with Bodipy-phenyl-C60 as the triplet photosensitizer in five solvents, 1,4-dioxane, dichlorobenzene, chlorobenzene, toluene, and tetrahydrofuran (THF). Although no significant solvent effect was observed in steady-state absorption and fluorescence emission spectra, the overall TTA upconversion quantum yields showed a profound dependence on solvent properties, i.e. 4.9% in 1,4-dioxane, 7.1% in dichlorobenzene, 6.7% in chlorobenzene, 4.6% in toluene, and 2.2% in THF (the maximum of 50%). Each elementary reaction step involved in the overall process was analyzed by applying femtosecond and nanosecond time-resolved transient absorption spectroscopy, revealing that the fluorescence emission of perylene was more significantly affected by the solvents in contrast to the other steps. Moreover, an extra intramolecular energy-transfer pathway of Bodipy-phenyl-C60 was found via the formation of charge-separated states in dichlorobenzene, chlorobenzene, and THF solvents, once being excited. These conclusions provide valuable clues to choose the most favorable solvent for the higher TTA upconversion efficiency in related applications.

Graphene nanoparticle strain sensors with modulated sensitivity through tunneling types transition

Highly sensitive strain sensors show great potential for use in wearable health monitoring, autonomous intelligent robots and biomimetic prosthetics. The current resistive strain sensors mainly work through piezoresistors. Here, the robust tunneling mechanism based nanoscale strain sensors with high sensitivity are reported. The strain sensors are fabricated from graphene nanoparticle film. The sensitivity of graphene nanoparticle strain sensors could be tunable through the modulation of tunneling type, suggesting a theoretical support in performance optimization of tunneling strain sensors. The output characterization indicates the direct tunneling (DT) and Fowler–Nordheim tunneling (FNT) are dominant for charge carrier transport in the low voltage and high voltage regions, respectively. It is found that gauge factors are ∼79 at low voltage of 0–4 V, and ∼110 at high voltage of 20–40 V, showing profound dependence on DT and FNT types. The strain sensor bearing 0.3% strain shows a great stability over 100 cycles at bias voltage of 1 V and 40 V, respectively. An integrated strain sensor array with 5 × 5 patterned graphene nanoparticle film on a polyethylene terephthalate substrate is fabricated and demonstrates great spatial strain distribution, guiding the design for flexible and transparent strain sensor e-skins.

Role of Local Polymer Conformations on the Diverging Glass Transition Temperatures and Dynamic Fragilities of Isotactic-, Syndiotactic-, and Atactic-Poly(methyl methacrylate)s

The profound stereosequence dependence of the glass transition temperature (Tg) of poly(methyl methacrylate)s (PMMAs) offers the possibility to evaluate any conformational contributions to their gl...

Cell Morphology on Poly(methyl methacrylate) Microstructures as Function of Surface Energy.

Whilst the significance of substrate topography as a regulator of cell function is well established, a systematic analysis of the principles underlying this is still unavailable. Here we evaluate the hypothesis that surface energy plays a decisive role in substrate-mediated modulation of cell phenotype by evaluation of cell behaviour on synthetic microstructures exhibiting pronounced differences in surface energy. These microstructures, specifically cubes and walls, were fabricated from a biocompatible base polymer, poly(methyl methacrylate), by variotherm injection molding. The dimensions of the cubes were 1 μm x 1 μm x 1 μm (height x width x length) with a periodicity of 1:1 and 1:5 and the dimensions of the walls 1 μm x 1 μm x 15 mm (height x width x length) with a periodicity of 1:1 and 1:5. Mold inserts were made by lithography and electroplating. The surface energy of the resultant microstructures was determined by static contact angle measurements. Light scanning microscopy of the morphology of NT2/D1 and MC3T3-E1 preosteoblast cells cultured on structured PMMA samples in both cases revealed a profound surface energy dependence. “Walls” appeared to promote significant cell elongation, whilst a lack of cell adhesion was observed on “cubes” with the lowest periodicity. Contact angle measurements on walls revealed enhanced surface energy anisotropy (55 mN/m max., 10 mN/m min.) causing a lengthwise spreading of the test liquid droplet, similar to cell elongation. Surface energy measurements for cubes revealed increased isotropic hydrophobicity (87° max., H2O). A critical water contact angle of ≤ 80° appears to be necessary for adequate cell adhesion. A “switch” for cell adhesion and subsequently cell growth could therefore be applied by, for example, adjusting the periodicity of hydrophobic structures. In summary cell elongation on walls and a critical surface energy level for cell adhesion could be produced for NT2/D1 and MC3T3-E1 cells by symmetrical and asymmetrical energy barrier levels. We, furthermore, propose a water-drop model providing a common physicochemical cause regarding similar cell/droplet geometries and cell adhesion on the investigated microstructures.

Metamagnetic transition and observation of spin-fluctuations in the antiferromagnetic Heusler compound Pd2MnIn

We report detailed investigations on the structural, magnetic, magneto-transport and calorimetric aspects of a partially ordered Heusler compound Pd2MnIn. The sample shows antiferomagnetic (AFM) state below around 120 K, though positive paramagnetic Curie temperature signifies a complex magnetic ground state with the presence of both ferromagnetic (FM) and AFM correlations. A clear spin-flop type metamagnetic transition is observed as evident from the magnetization and resistivity data. However, non-saturation of magnetization even at 145 kOe of applied field implies that the high field state may be a spin canted state, originating from the enhanced FM correlations by field induced conduction electron spin polarization. The sample shows a profound quadratic temperature dependence of resistivity below about 20–25 K indicating a spin-fluctuation dominated low temperature region. Previous electronic structure calculations show the existence of a subtle balance between superexchange mediated AFM state and an RKKY (Ruderman–Kittel–Kasuya–Yoshida) interaction mediated FM state in Pd2MnIn. Such competing AFM-FM correlations can be accounted for the observed spin fluctuations.

Quantum chaos in spin-1/2 two-leg ladders

In this paper, we study numerically the emergence of quantum chaos in the antiferromagnetic (AF) Heisenberg two-leg spin-1/2 ladder. We investigate the mutual effects of magnetic defects and couplings (rung or leg) on the statistical properties of the energy spectrum using the exact diagonalization technique. The system is chaotic when the leg and rung coupling strengths are equal, and even adding a strong magnetic defect does not change the energy distribution. Introducing two defects also does not change the level spacing distribution. We conclude that the system not strongly depend on the number of defects. However, when one of the couplings (rung or leg) is much larger than the other, level spacing distribution shows a profound dependence on it and a transition from chaotic to the integrable regime is found.

Effect of Electrolyte Compositions on Cycling Performance of Li-Ion Full Cells with Si-Graphite Composite Electrodes

The demand for high energy densities in Li-ion batteries (LIBs) necessitates exploring bottlenecks of cell performance. Layered oxide positive electrodes, such as LiNixCoyMn1-x-yO2 (NCM), and silicon-graphite composite (Si-Gr) negative electrodes in a LIB undergo a series of complex structural and compositional changes during electrochemical cycling. The induced changes have a direct influence on the energy and power output from a battery and a profound dependence on the cycling or aging conditions. The promise of multifold enhancement in energy densities of LIBs using Si based negative electrodes is accompanied by the limited stability of the electrode-electrolyte interface. In commercial LIBs, the solid electrolyte interphase (SEI) layer on the graphite negative electrode facilitates Li+ ion conduction and minimizes reduction of the electrolyte. In cells with Si- containing negative electrodes, the large volume changes of Si during cycling results in continuous degradation of the SEI layer. The formation of a new SEI on the newly-exposed Si surfaces during subsequent cycling causes further trapping of Li+ ions, contributing to performance loss. In the present study, full cells with NCM 523 cathode, Si-Gr (containing 15 wt% Si) anode, and a baseline electrolyte (1.2 M LiPF6 in Ethylene Carbonate/Ethyl Methyl Carbonate, 3:7 w/w) were tested under calendar life ageing and cycle life ageing protocols between 3 and 4.1 V. The cycle-life cells showed ~92% capacity loss after 100 cycles, while the calendar-life cells showed ~13% capacity loss; the reasons for this difference will be highlighted during the presentation.1 In order to further improve capacity retention we studied the effect of various additives to the baseline electrolyte, and also examined EC-free electrolyte systems. Advanced diagnostic techniques, including X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and scanning electron microscopy (SEM) were used to examine the effect of these additives on the SEI layer.2,3 Insights from electrochemical response in conjunction with post-mortem characterization studies have fostered deeper understanding of the charge transfer mechanisms and the properties of the interfacial layers in the blended negative electrodes. Fundamental knowledge of the nature of this dynamic SEI layer is essential to design better surface films and achieve stable electrochemical cycling. Support from David Howell, Brian Cunningham, and Peter Faguy of the U.S. Department of Energy’s Office of Vehicle Technologies is gratefully acknowledged. This work was performed under the auspices of the US Department of Energy, Office of Vehicle Technologies, Hybrid and Electric Systems, under Contract No. DE-AC02-06CH11357 K. Kalaga et al., manuscript in preparation (2017). K. Kalaga, I.A. Shkrob, R.T. Haasch, C. Peebles, J. Bareño, D.P. Abraham, “Auger Electrons as Probes for Composite Micro and Nanostructured Materials: Application to Solid Electrolyte Interphases in Graphite and Silicon-Graphite Electrodes”, J. Phys. Chem. C 2017, 121, 23333−23346. J. Bareño, I.A. Shkrob, J.A. Gilbert, M. Klett, D.P. Abraham, “Capacity Fade and Its Mitigation in Li-ion Cells with Silicon-Graphite Electrodes”, J. Phys. Chem. C 121 (2017), pp 20640-20649.

The Entropic Body: Primitive Anxieties and Secondary Skin Formation in Anorexia Nervosa

This paper develops a metapsychological view of anorexia nervosa, including not only its symptomatic presentation but also its etiology and characteristic psychic and relational styles. Because patients with anorexia are understood as not having internalized maternal comforting functions in the period of separation-individuation, they are unable to digest trauma experiences of infancy. I argue that the anorexic patient’s disturbed relationship with food reflects distortions in transitional object usage. Lacking the ability to contain intense anxieties about disintegration and falling apart, patients with anorexia must find other ways to hold themselves together. The fear of getting fat expressed by these patients is one way that this fear of disintegration is expressed. Furthermore, the almost addictive experience of emaciation holds the personality together. Elaborating this idea, I develop the notion of the entropic body, a particular version of the false body (Goldberg, 2004) employed by patients with anorexia nervosa in an attempt to compensate for absent maternal comforting functions. This body-state (Petrucelli, 2014), which develops against a background of profound early trauma, eschews hunger and dependence in favor of omnipotently controlled protection.

Tracheostomy reversal years after patient lost to follow-up

BackgroundPediatric tracheostomies occur for various reasons, including prologned intubation, and require a multidisciplinary approach with routine follow-up.Case presentationThis report reviews the history and clinical outcome of a 29 year old female patient who was lost to follow-up for nearly two decades after a pediatric tracheostomy. When she presented to the Otolaryngology service as an adult the original indication for tracheostomy had resolved and decannulation was initiated, but a profound psychological dependence had developed.ConclusionThis case outlines the importance of regular follow-up for tracheostomy patients, as well as health care barriers faced in remote rural communities.

Rare earth indates (RE: La-Yb): influence of the synthesis route and heat treatment on the crystal structure.

Rare earth indates are an interesting class of compounds with rich crystallography. The present study explores the crystallographic phases observed in REInO3 (RE: La-Yb) systems and their dependence on synthesis routes and annealing temperature. All REInO3 compositions were synthesized by a solid state route as well as gel-combustion synthesis (GC) followed by annealing at different temperatures. The systems were well characterized by powder XRD studies and were analysed by Rietveld refinement for the structural parameters. The cell parameters were observed to decrease in accordance with the trend in ionic radii on proceeding from lighter to heavier rare earth ions. Interestingly, the synthesis route and the annealing temperature had a profound bearing on the phase relationships observed in the REInO3 series. The solid state synthesized samples depicted an orthorhombic phase (Pbnm) field for LaInO3 to SmInO3, followed by a hexagonal-type phase (P63cm) for GdInO3 to DyInO3. However, the phase field distribution was greatly influenced upon employing gel-combustion (GC) wherein both single-phasic hexagonal and orthorhombic phase fields were found to shrink. Annealing the GC-synthesized compositions to still higher temperatures (1250 °C) further evolved the phase boundaries. An important outcome of the study is observance of polymorphism in SmInO3 which crystallized in the hexagonal phase when synthesized by GC and orthorhombic phase by solid state synthesis. This reveals the all-important role played by synthesis conditions. The existence and energetics of the two polymorphs have been elucidated and discussed with the aid of theoretical studies.

PAX3-FOXO1 Establishes Myogenic Super Enhancers and Confers BET Bromodomain Vulnerability.

Alveolar rhabdomyosarcoma is a life-threatening myogenic cancer of children and adolescent young adults, driven primarily by the chimeric transcription factor PAX3-FOXO1. The mechanisms by which PAX3-FOXO1 dysregulates chromatin are unknown. We find PAX3-FOXO1 reprograms the cis-regulatory landscape by inducing de novo super enhancers. PAX3-FOXO1 uses super enhancers to set up autoregulatory loops in collaboration with the master transcription factors MYOG, MYOD, and MYCN. This myogenic super enhancer circuitry is consistent across cell lines and primary tumors. Cells harboring the fusion gene are selectively sensitive to small-molecule inhibition of protein targets induced by, or bound to, PAX3-FOXO1-occupied super enhancers. Furthermore, PAX3-FOXO1 recruits and requires the BET bromodomain protein BRD4 to function at super enhancers, resulting in a complete dependence on BRD4 and a significant susceptibility to BRD inhibition. These results yield insights into the epigenetic functions of PAX3-FOXO1 and reveal a specific vulnerability that can be exploited for precision therapy.Significance: PAX3-FOXO1 drives pediatric fusion-positive rhabdomyosarcoma, and its chromatin-level functions are critical to understanding its oncogenic activity. We find that PAX3-FOXO1 establishes a myoblastic super enhancer landscape and creates a profound subtype-unique dependence on BET bromodomains, the inhibition of which ablates PAX3-FOXO1 function, providing a mechanistic rationale for exploring BET inhibitors for patients bearing PAX-fusion rhabdomyosarcoma. Cancer Discov; 7(8); 884-99. ©2017 AACR.This article is highlighted in the In This Issue feature, p. 783.

Design and Management of Battery-Supercapacitor Hybrid Electrical Energy Storage Systems for Regulation Services

Regulation services (RS) play an important role in maintaining the stability of electric grids by correcting for short-term mismatches between electricity generation and demand. RS providers dynamically supply electricity to the grid or consume electricity from it, in response to regulation signals, in return for economic compensation. This capability is commonly realized through large-scale electrical energy storage (EES) systems based on batteries. However, the highly transient nature of the regulation signals implies that the batteries used for RS are subject to frequent charge and discharge cycles, leading to shortened battery life and thereby impacting the profitability of RS. In this work, we explore the use of hybrid EES (HEES) systems, which combine batteries and supercapacitors, to improve the profitability of RS. HEES systems have the potential to reduce the cost of providing RS by utilizing supercapacitors to respond to the high-frequency components of the regulation signal, prolonging battery life. However, realizing this potential presents several challenges. First, the benefits of HEES systems have a profound dependence on the type of hybrid topology (i.e., active or passive), which results in a tradeoff between the implementation cost and the utilization of the supercapacitor capacity. Second, the allocation of energy storage capacity to batteries and supercapacitors should be carefully determined in the design phase because the reduction in battery replacement cost due to the use of supercapacitors must be balanced against the increased upfront cost for supercapacitors. Third, active HEES systems involve the problem of managing the power flows to batteries and supercapacitors so as to realize maximum cost benefits. To address these challenges, we present a framework for the design and management of a HEES system, so as to maximize the profit from the perspective of an RS provider. This framework consists of i) a design-time capacity optimization phase that determines the best allocation of capacity to batteries and supercapacitors and ii) a run-time management scheme that selects how the different storage devices are orchestrated considering their characteristics and the incoming regulation signal. Our experiments show that, with the proposed capacity optimization and management framework, the use of a passive or an active HEES system can improve the profit of RS providers by 1.16 $\times$ or 5.44 $\times$ , respectively.

Sex Work as an Emerging Risk Factor for Human Immunodeficiency Virus Seroconversion Among People who Inject Drugs in the SurvUDI Network.

Recent analyses have shown an emerging positive association between sex work and human immunodeficiency virus (HIV) incidence among people who inject drugs (PWIDs) in the SurvUDI network. Participants who had injected in the past 6 months were recruited across the Province of Quebec and in the city of Ottawa, mainly in harm reduction programs. They completed a questionnaire and provided gingival exudate for HIV antibody testing. The associations with HIV seroconversion were tested with a Cox proportional hazard model using time-dependent covariables including the main variable of interest, sexual activity (sex work; no sex work; sexually inactive). The final model included significant variables and confounders of the associations with sexual activity. Seventy-two HIV seroconversions were observed during 5239.2 person-years (py) of follow-up (incidence rates: total = 1.4/100 py; 95% confidence interval [CI], 1.1-1.7; sex work = 2.5/100 py; 95% CI, 1.5-3.6; no sex work = 0.8/100 py; 95% CI, 0.5-1.2; sexually inactive = 1.8/100 py; 95% CI, 1.1-2.5). In the final multivariate model, HIV incidence was significantly associated with sexual activity (sex work: adjusted hazard ratio [AHR], 2.19; 95% CI, 1.13-4.25; sexually inactive: AHR, 1.62; 95% CI, 0.92-2.88), and injection with a needle/syringe used by someone else (AHR, 2.84; 95% CI, 1.73-4.66). Sex work is independently associated with HIV incidence among PWIDs. At the other end of the spectrum of sexual activity, sexually inactive PWIDs have a higher HIV incidence rate, likely due to more profound dependence leading to increased vulnerabilities, which may include mental illness, poverty, and social exclusion. Further studies are needed to understand whether the association between sex work and HIV is related to sexual transmission or other vulnerability factors.

Cornucopia of Nanoscale Ordered Phases in Sphere-Forming Tetrablock Terpolymers.

We report the phase behavior of a series of poly(styrene)-b-poly(isoprene)-b-poly(styrene)'-b-poly(ethylene oxide) (SIS'O) tetrablock terpolymers. This study was motivated by self-consistent field theory (SCFT) calculations that anticipate a rich array of sphere-forming morphologies with variations in the molecular symmetry parameter τ = NS/(NS + NS'), where N is the block degree of polymerization and the volume fraction of O is less than about 0.22. Eight SIS'O samples, with τ ranging from 0.21 to 0.73, were synthesized and investigated using small-angle X-ray scattering and transmission electron microscopy, yielding evidence of nine different spherical phases: hexagonal, FCC, HCP, BCC, rhombohedral (tentative), liquid-like packing, dodecagonal quasicrystal, and Frank-Kasper σ and A15 phases. At temperatures close to the order-disorder transition, these tetrablocks behave as pseudo-[SIS']-O diblocks and form equilibrium morphologies mediated by facile chain exchange between micelles. Transition from equilibrium to nonequilibrium behavior occurs at a temperature (Terg) several tens of degrees below the order-disorder transition temperature, speculated to be coincident with the loss of ergodicity, as chain exchange is arrested due to increased segregation strength between the core (O) and corona (SIS') blocks. Nonequilibrium ordered structures form when T < Terg; these are interpreted using SCFT calculations to elucidate the free energy landscape driving ordering in the S and I block matrix. These experiments demonstrate a profound dependence on phase stability with variations in τ and temperature, providing insights into the formation of ordered phase symmetry in this class of asymmetric multiblock polymers.

First-principles study of the structural and dynamic properties of the liquid and amorphous Li–Si alloys

We have performed density functional theory calculations and ab initio molecular dynamics to investigate the structures and dynamic properties of the liquid and amorphous LixSi alloys over a range of composition from x = 1.0 - 4.8. Our results show that Si atoms can form a variety of covalently bonded polyanions with diverse local bonding structures in the liquid alloys. Like in c-LiSi, Si atoms can form a continuous bond network in liquid Li1.0Si at 1050 K, while it gradually disintegrates into many smaller Si polyanions as the Li content increases in the alloys. The average sizes of Si polyanions in these liquid alloys were found to be relatively larger than those in their crystalline counterparts, which can even persist in the highly lithiated Li4.81Si alloy at 1500 K. Our results also show that amorphous LixSi alloys have similar local bonding structures but a largely increased short-range order as compared to their liquid counterparts. The differences between the average coordination number of each atomic pair in amorphous solids and that in the liquids are less than 1.1. Furthermore, our calculations reveal that Li and Si atoms can exhibit very distinct dynamic behaviors in the liquids and their diffusivities appear to be largely dependent on the chemical composition of the alloys. The diffusivity of Li was found to increase with the Li content in the alloys primarily because of the reduced interactions between Li and Si atoms, while the Si diffusivity also increases due to the gradual disintegration of the strongly interconnected Si bond network. The diffusivity of Li in amorphous LixSi was predicted to lie in the range between 10(-7) and 10(-9) cm(2)/s at 300 K, which is more than 20-fold larger than that of Si over the composition range considered. Our calculations further show that the diffusivities of both Li and Si can increase by two orders of magnitude as x increases from 1.0 to 3.57 in amorphous LixSi, indicating a more profound dependence on the alloy composition than those in the liquid state.

On the selection of gantry and collimator angles for isocenter localization using Winston-Lutz tests.

In Winston‐Lutz (WL) tests, the isocenter of a linear accelerator (linac) is determined as the intersection of radiation central axes (CAX) from multiple gantry, collimator, and couch angles. It is well known that the CAX can wobble due to mechanical imperfections of the linac. Previous studies suggested that the wobble varies with gantry and collimator angles. Therefore, the isocenter determined in the WL tests has a profound dependence on the gantry and collimator angles at which CAX are sampled. In this study, we evaluated the systematic and random errors in the isocenters determined with different CAX sampling schemes. Digital WL tests were performed on six linacs. For each WL test, 63 CAX were sampled at nine gantry angles and seven collimator angles. Subsets of these data were used to simulate the effects of various CAX sampling schemes. An isocenter was calculated from each subset of CAX and compared against the reference isocenter, which was calculated from 48 opposing CAX. The differences between the calculated isocenters and the reference isocenters ranged from 0 to 0.8 mm. The differences diminished to less than 0.2 mm when 24 or more CAX were sampled. Isocenters determined with collimator 0° were vertically lower than those determined with collimator 90° and 270°. Isocenter localization errors in the longitudinal direction (along the axis of gantry rotation) showed a strong dependence on the collimator angle selected. The errors in all directions were significantly reduced when opposing collimator angles and opposing gantry angles were employed. The isocenter localization errors were less than 0.2 mm with the common CAX sampling scheme, which used four cardinal gantry angles and two opposing collimator angles. Reproducibility studies on one linac showed that the mean and maximum variations of CAX during the WL tests were 0.053 mm and 0.30 mm, respectively. The maximal variation in the resulting isocenters was 0.068 mm if 48 CAX were used, or 0.13 mm if four CAX were used. Quantitative results from this study are useful for understanding and minimizing the isocenter uncertainty in WL tests.PACS number: 87.56.Fc

Haploid Genetic Screen Reveals a Profound and Direct Dependence on Cholesterol for Hantavirus Membrane Fusion.

ABSTRACTHantaviruses cause hemorrhagic fever with renal syndrome (HFRS) in the Old World and a highly fatal hantavirus cardiopulmonary syndrome (HCPS) in the New World. No vaccines or antiviral therapies are currently available to prevent or treat hantavirus disease, and gaps in our understanding of how hantaviruses enter cells challenge the search for therapeutics. We performed a haploid genetic screen in human cells to identify host factors required for entry by Andes virus, a highly virulent New World hantavirus. We found that multiple genes involved in cholesterol sensing, regulation, and biosynthesis, including key components of the sterol response element-binding protein (SREBP) pathway, are critical for Andes virus entry. Genetic or pharmacological disruption of the membrane-bound transcription factor peptidase/site-1 protease (MBTPS1/S1P), an SREBP control element, dramatically reduced infection by virulent hantaviruses of both the Old World and New World clades but not by rhabdoviruses or alphaviruses, indicating that this pathway is broadly, but selectively, required by hantaviruses. These results could be fully explained as arising from the modest depletion of cellular membrane cholesterol that accompanied S1P disruption. Mechanistic studies of cells and with protein-free liposomes suggested that high levels of cholesterol are specifically needed for hantavirus membrane fusion. Taken together, our results indicate that the profound dependence on target membrane cholesterol is a fundamental, and unusual, biophysical property of hantavirus glycoprotein-membrane interactions during entry.

Far-from-equilibrium spin transport in Heisenberg quantum magnets.

We study experimentally the far-from-equilibrium dynamics in ferromagnetic Heisenberg quantum magnets realized with ultracold atoms in an optical lattice. After controlled imprinting of a spin spiral pattern with an adjustable wave vector, we measure the decay of the initial spin correlations through single-site resolved detection. On the experimentally accessible time scale of several exchange times, we find a profound dependence of the decay rate on the wave vector. In one-dimensional systems, we observe diffusionlike spin transport with a dimensionless diffusion coefficient of 0.22(1). We show how this behavior emerges from the microscopic properties of the closed quantum system. In contrast to the one-dimensional case, our transport measurements for two-dimensional Heisenberg systems indicate anomalous superdiffusion.

Microstructure – twinning and hexad multiplet(s) in lithium-rich layered cathode materials for lithium-ion batteries

Li-rich cathode materials synthesized through the solution combustion method essentially exhibits a super-lattice layered structure and appears to have an edge over conventional cathode materials in terms of a good capacity with fade control. The cobalt content in this Li-rich cathode material is vital in determining the morphology, microstructure, high reversible redox peak and stable charge–discharge cycling. A typical Li-rich cathode with a Li1.2Ni0.13Mn0.54Co0.13O2 composition exhibits strange microstructure features in the SAED pattern viz., the simultaneous occurrence of twinning, and the hexad multiplets patterns yielded a good discharge capacity of 231 mA h g−1. Whilst it is the microstructure features, which have a profound dependence on the cobalt content appears to have control on the capacity. On the basis of these microstructural changes revealed in the SAED pattern and cation ordering in the superlattice structure, an attempt has been made to explain the dependence of cobalt content vs. capacity performance in Li-ion batteries.

“Green” scale inhibitors in water treatment processes: the case of silica scale inhibition

This paper focuses on scale control approaches using a number of “green” silica scale inhibitors. These findings may be of interest to chemists and engineers in the fields of cooling and boiler water, pulp and paper, detergents, oil, gas, etc. In light of increasing environmental concerns, this research acquires significant interest. Also, in this paper, the effects of biological and synthetic polymers on the formation of amorphous silica are discussed. The importance of synergies between polyelectrolytes on silica inhibition is also discussed. A specific example of a zwitterionic polymer phosphonomethylated chitosan (PCH) is further analyzed for its inhibitory activity. Specifically, the ability of PCH to retard silicic acid condensation at circumneutral pH in aqueous supersaturated solutions is explored. Furthermore, the effects of either purely cationic (polyethyleneimine, PEI) or purely anionic (carboxymethylinulin) polyelectrolytes on the inhibitory activity of PCH are systematically studied. It was found that the action of inhibitor blends is not cumulative. PCH/PEI blends stabilize the same level of silicic acid as PCH alone in both short-term (8 h) and long-term (72 h) experiments. Lastly, six polyethylene glycol polymers are used as silica scale inhibitors. Their Molecular Weights range from 1,550 to 20,000. There is a profound dependence of inhibitory performance on the additive Molecular Weight. However, this dependence seems to be less significant for Molecular Weights > 10,000. Mechanistic implications will be discussed as well.