bluuebunny/crossref_metadata_2025 huggingface dataset:
Business opportunity assessment in Slovene organic spelt processing: application of real options model
Authors: Pažek Karmen , Rozman Črtomir
Published: February 2011

Decision making in organic farming is related to risk and uncertainty, and options must be evaluated in the decision-making process. This paper presents the methodology of an integrated deterministic simulation system (KARSIM 1.0) application for decision-making support on organic farms in northeastern Slovenia. An emphasis to modify the net present value (NPVt) criterion by incorporating the real options approach was made. Its application is shown in organic spelt (Triticum aestivum ssp. spelta McKey) production and processing using two real options approaches, the Black–Scholes and binomial models. The NPVt indicates that the decision to process spelt for animal fodder is financially unfeasible, while the real options approach differentiates the results by organic spelt grain and flour production for human nutrition. It may be concluded that the real options approach can be useful when assessing projects with uncertainty, sunk costs and irreversibility, and it can provide for examining agricultural investment decisions.
Chromatin remodeling resets the immune system to protect against autoimmune diabetes in mice
Authors: Patel Tejas , Patel Vasu , Singh Rajvir , Jayaraman Sundararajan
Published: February 2011

Epigenetic alteration of the genome has been shown to provide palliative effects in mouse models of certain human autoimmune diseases. We have investigated whether chromatin remodeling could provide protection against autoimmune diabetes in NOD mice. Treatment of female mice during the transition from prediabetic to diabetic stage (18–24 weeks of age) with the well‐characterized histone deacetylase inhibitor, trichostatin A effectively reduced the incidence of diabetes. However, similar treatment of overtly diabetic mice during the same time period failed to reverse the disease. Protection against diabetes was accompanied by histone hyperacetylation in pancreas and spleen, enhanced frequency of CD4+ CD62L+ cells in the spleen, reduction in cellular infiltration of islets, restoration of normoglycemia and glucose‐induced insulin release by beta cells. Activation of splenic T lymphocytes derived from protected mice in vitro with pharmacological agents that bypass the antigen receptor or immobilized anti‐CD3 antibody resulted in enhanced expression of Ifng mRNA and protein without altering the expression of Il4, Il17, Il18, Inos and Tnfa genes nor the secretion of IL‐2, IL‐4, IL‐17 and TNF‐α proteins. Consistently, expression of the transcription factor involved in Ifng transcription, Tbet/Tbx21 but not Gata3 and Rorgt, respectively, required for the transcription of Il4 and Il17, was upregulated in activated splenocytes of protected mice. These results indicate that chromatin remodeling can lead to amelioration of diabetes by using multiple mechanisms including differential gene transcription. Thus, epigenetic modulation could be a novel therapeutic approach to block the transition from benign to frank diabetes.
Lactobacillus bulgaricus OLL1181 activates the aryl hydrocarbon receptor pathway and inhibits colitis
Authors: Takamura Takeyuki , Harama Daisuke , Fukumoto Suguru , Nakamura Yuki , Shimokawa Naomi , Ishimaru Kayoko , Ikegami Shuji , Makino Seiya , Kitamura Masanori , Nakao Atsuhito
Published: February 2011

Increasing evidence suggests that the aryl hydrocarbon receptor (AhR) pathway has an important role in the regulation of inflammatory responses. Most recently, we have shown that the activation of the AhR pathway by a potent AhR agonist inhibits the development of dextran sodium sulfate (DSS)‐induced colitis, a model of human ulcerative colitis, by the induction of prostaglandin E2 (PGE2) in the large intestine. Because several strains of probiotic lactic acid bacteria have been reported to inhibit DSS‐induced colitis by unidentified mechanisms, we hypothesized that particular strains of lactic acid bacterium might have the potential to activate the AhR pathway, thereby inhibiting DSS‐induced colitis. This study investigated whether there are specific lactic acid bacterial strains that can activate the AhR pathway, and if so, whether this AhR‐activating potential is associated with suppression of DSS‐induced colitis. By using AhR signaling reporter cells, we found that Lactobacillus bulgaricus OLL1181 had the potential to activate the AhR pathway. OLL1181 also induced the mRNA expression of cytochrome P450 family 1A1 (CYP1A1), a target gene of the AhR pathway, in human colon cells, which was inhibited by the addition of an AhR antagonist, α‐naphthoflavon (αNF). In addition, mice treated orally with OLL1181 showed an increase in CYP1A1 mRNA expression in the large intestine and amelioration of DSS‐induced colitis. Thus, OLL1181 can induce activation of the intestinal AhR pathway and inhibit DSS‐induced colitis in mice. This strain of lactic acid bacterium has therefore the potential to activate the AhR pathway, which may be able to suppress colitis.
Electrostatics at the nanoscale
Authors: Walker David A. , Kowalczyk Bartlomiej , de la Cruz Monica Olvera , Grzybowski Bartosz A.
Published: February 2011

Electrostatics across all length scales! Electrostatics can mediate assembly of objects on multiple length scales – but at the nanoscale things become a bit less predictable.
Mast cells in health and disease
Authors: Weller Charlotte L. , Collington Sarah J. , Williams Tim , Lamb Jonathan R.
Published: February 2011

Although MCs (mast cells) were discovered over 100 years ago, for the majority of this time their function was linked almost exclusively to allergy and allergic disease with few other roles in health and disease. The engineering of MC-deficient mice and engraftment of these mice with MCs deficient in receptors or mediators has advanced our knowledge of the role of MCs in vivo. It is now known that MCs have very broad and varied roles in both physiology and disease which will be reviewed here with a focus on some of the most recent discoveries over the last year. MCs can aid in maintaining a healthy physiology by secreting mediators that promote wound healing and homoeostasis as well as interacting with neurons. Major developments have been made in understanding MC function in defence against pathogens, in recognition of pathogens as well as direct effector functions. Probably the most quickly developing area of understanding is the involvement and contribution MCs make in the progression of a variety of diseases from some of the most common diseases to the more obscure.
Endothelin-1 vasoconstriction and the age-related decline in endothelium-dependent vasodilatation in men
Authors: Westby Christian M. , Weil Brian R. , Greiner Jared J. , Stauffer Brian L. , Desouza Christopher A.
Published: February 2011

ET (endothelin)-1, a potent vasoconstrictor peptide released by the endothelium, plays an important role in vasomotor regulation and has been linked to diminished endothelial vasodilator capacity in several pathologies associated with human aging, including hypertension, Type 2 diabetes and coronary artery disease. However, it is currently unknown whether the decline in endothelial vasodilatation with advancing age is due to elevated ET-1 vasconstrictor activity. Accordingly, we tested the hypothesis that the age-related impairment in ACh (acetylcholine)-mediated endothelium-dependent vasodilatation is due, at least in part, to increased ET-1-mediated vasoconstrictor tone. FBF (forearm blood flow) responses to ACh, SNP (sodium nitroprusside) and BQ-123 (ETA receptor blocker) were determined in 14 young (age, 25±1 years) and 14 older (age, 61±2 years) healthy non-obese men. Additionally, FBF responses to ACh were determined in the presence of ETA blockade. Vasodilatation to ACh was lower (approx. 25%; P<0.05) in the older men (from 4.9±0.2 to 13.9±0.9 ml·100 ml−1 of tissue·min−1) compared with the young men (4.6±0.3 to 17.2±1.0 ml·100 ml−1 of tissue·min−1). There were no differences in FBF responses to SNP between the young (4.8±0.3 to 18.5±0.3 ml·100 ml−1 of tissue·min−1) and older (5.1±0.3 to 17.3±0.8 ml·100 ml−1 of tissue·min−1) men. In the young men, resting FBF was not significantly altered by BQ-123, whereas, in the older men, FBF increased approx. 25% in response to BQ-123 infusion (P<0.05). Co-infusion of ACh with BQ-123 resulted in an approx. 20% increase in the ACh-induced vasodilatation in older men compared with saline. In contrast, FBF responses to ACh were not significantly altered by ETA blockade in the young men. In conclusion, these results demonstrate that ET-1 vasoconstrictor activity contributes, at least in part, to diminished endothelium-dependent vasodilatation in older men.
Theory of correlated two-particle activated glassy dynamics: General formulation and heterogeneous structural relaxation in hard sphere fluids
Authors: Sussman Daniel M. , Schweizer Kenneth S.
Published: February 2011

We generalize the nonlinear Langevin equation theory of activated single particle dynamics to describe the correlated motion of two tagged spherical particles in a glass- or gel-forming fluid as a function of their initial separation. The theory is built on the concept of a two-dimensional dynamic free energy surface which quantifies the forces on two particles moving in a cooperative manner. For the hard sphere fluid, above a threshold volume fraction we generically find two relaxation channels corresponding largely, but not exclusively, to a center-of-mass-like displacement and a radial separation of the two tagged particles. The entropic barriers and mean first passage times are computed and found to systematically vary with volume fraction and initial particle separation; both oscillate as a function of the latter in a manner related to the equilibrium pair correlation function. A dynamic correlation length is estimated as the length scale beyond which the two-particle activated dynamics becomes uncorrelated in space and time, and is found to modestly grow with increasing mean relaxation time. The theory is also applied to a simplified model of cage escape, the elementary step of structural relaxation. Predictions for characteristic relaxation times, translation–relaxation decoupling, and stretched-exponential decay of time correlation functions are obtained. A novel mechanism for understanding why strong decoupling emerges in the activated regime, but stretched nonexponential time correlation functions do not change shape as the mean relaxation time grows, is presented and favorably compared with experiment. The theory may serve as a starting point for constructing a predictive model of multiple correlated caging and hopping (forward and backward) events of a pair of tagged particles.
Note: A portable pulsed neutron source based on the smallest sealed-type plasma focus device
Authors: Niranjan Ram , Rout R. K. , Mishra Prabhat , Srivastava Rohit , Rawool A. M. , Kaushik T. C. , Gupta Satish C.
Published: February 2011

Development and operation of a portable and compact pulsed neutron source based on sealed-type plasma focus (PF) device are reported. The unit is the smallest sealed-type neutron producing PF device. The effective volume of the PF unit is 33 cm3 only. A compact size single capacitor (4 μF) is used as the energy driver. A battery based power supply unit is used for charging the capacitor and triggering the spark gap. The PF unit is operated at 10 kV (200 J) and at a deuterium gas filling pressure of 8 mb. The device is operated over a time span of 200 days and the neutron emissions have been observed for 200 shots without changing the gas in between the shots. The maximum yield of this device is 7.8 × 104 neutrons/pulse. Beyond 200 shots the yield is below the threshold (1050 neutrons/pulse) of our 3He detector. The neutron energy is evaluated using time of flight technique and the value is (2.49 ± 0.27) MeV. The measured neutron pulse width is (24 ± 5) ns. Multishot and long duration operations envisage the potentiality of such portable device for repetitive mode of operation.
Sorting of Brownian rods by the use of an asymmetric potential
Authors: Gralinski Ian , Neild Adrian , Ng Tuck Wah , Muradoglu Murat S.
Published: February 2011

We present here a method for sorting nanometer scale Brownian rods by using a switching asymmetric periodic potential. A two stage sorting process is used to isolate particles with specific dimensions, with acceptable sorting times as well as realizable potential barrier lengths. The method was tested using computer simulations. The ability to sort the nanometer scale anisotropic particles, such as gold nanorods, portends important applications in large scale data recording, photothermal surgery, and bioimaging.
Experimental study on subband structures and hole transport in (110) Si p-type metal-oxide-semiconductor field-effect transistors under high magnetic field
Authors: Takahashi Tsunaki , Kodera Tetsuo , Oda Shunri , Uchida Ken
Published: February 2011

The band structures and carrier transport in p-type metal-oxide-semiconductor field-effect transistors (pMOSFETs) fabricated on (110) Si bulk wafers are thoroughly studied over a wide temperature range under high magnetic fields. The sheet conductance, G, versus gate voltage, Vg, characteristics at the temperature of 2 K under the magnetic field of greater than 4 T show clear Shubnikov–de Haas (SdH) oscillations. We observed two types of the SdH oscillations: the shorter-period oscillations at lower gate voltages and the longer-period oscillations at higher gate voltages. The observation of the two types of oscillations indicates that the degenerated hole bands in bulk Si are split into the higher energy band (H band) and the lower energy band (L band) in (110) pMOSFETs. We demonstrated that the L band has higher hole mobility, μh, and lighter density-of-state mass, mDOS, than those of the H band. The energy split between the two bands, ΔE, is experimentally evaluated to be as large as 38 meV at the surface hole density of 4×1012 cm−2. Since the μh of the H band is lower, the increase of the occupancy in the H band with an increase in Vg leads to the low-temperature local G minimum in G-Vg characteristics. The higher μh in the L band and the large L-band occupancy due to the large ΔE contribute to the excellent performance of (110) pMOSFETs. However, because finite holes still populate in the H band, it is important to minimize the H-band contribution for the improvement of the performance of (110) pMOSFETs.
Structural and electronic interaction at CuO-hexa-peri-hexabenzocoronene hybrid interface
Authors: Singh Bharti , Mehta B. R. , Singh M. , Gupta Govind , Dössel L. , Feng X. , Müllen K.
Published: February 2011

Interfacial interaction at hybrid interfaces results in structural and electronic properties different from organic and inorganic components. In this study, x-ray photoelectron spectroscopy analysis carried out on CuO-hexa-peri-hexabenzocoronene (HBC) bilayers shows the appearance of an additional C 1s peak at lower energy due to Cu–C interaction. Spectroscopic ellipsometry investigation shows that interfacial layer (∼4 nm) has absorption features related to Cu–C bonding, modified HBC valence states, and Cu2+-π electron interaction. The observed resistive switching property of the CuO-HBC layers is considerably different from junction properties of HBC and CuO layers and is directly related to the hybrid interfacial layer.
Note: Observation and analysis of the aberration in a photoacoustic imaging system
Authors: Chen Zhanxu , Tang Zhilie , Wan Wei
Published: February 2011

Acoustic lens is applied in the research of photoacoustic imaging. The aberration is always inevitable due to the existence of the acoustic lens, and it influences the resolution of the imaging system severely. However, the imaging system based on an acoustic lens also provides a new method for observing the aberration of a system and testing the quality of the acoustic lens. In this paper, a method of observing the aberration of photoacoustic imaging system is reported, and the causes of aberrations are discussed based on the theory of lens aberration. All these would be helpful to correct the aberration and improve the resolving power of acoustic lens.
Depletion at solid/liquid interfaces: Flowing hexadecane on functionalized surfaces
Authors: Gutfreund Philipp , Wolff Max , Maccarini Marco , Gerth Stefan , Ankner John F. , Browning Jim , Halbert Candice E. , Wacklin Hanna , Zabel Hartmut
Published: February 2011

We present a neutron reflectivity study on interfaces in contact with flowing hexadecane, which is known to exhibit surface slip on functionalized solid surfaces. The single crystalline silicon substrates were either chemically cleaned Si(100) or Si(100) coated by octadecyl-trichlorosilane (OTS), which resulted in different interfacial energies. The liquid was sheared in situ and changes in reflectivity profiles were compared to the static case. For the OTS surface, the temperature dependence was also recorded. For both types of interfaces, density depletion of the liquid at the interface was observed. In the case of the bare Si substrate, shear load altered the structure of the depletion layer, whereas for the OTS covered surface no effect of shear was observed. Possible links between the depletion layer and surface slip are discussed. The results show that, in contrast to water, for hexadecane the enhancement of the depletion layer with temperature and interfacial energy reduces the amount of slip. Thus a density depletion cannot be the origin of surface slip in this system.
Magnetodielectric response of square-coordinated MnO2 unit in cubic BiMn7O12
Authors: Imamura N. , Singh K. , Pelloquin D. , Simon Ch. , Sasagawa T. , Karppinen M. , Yamauchi H. , Maignan A.
Published: February 2011

The magnetodielectric (MD) effect for BiMn7O12 with the cubic A′A″3B4O12-type A-site-ordered perovskite structure has been investigated. A clear negative MD response around and beyond TN has been observed and attributed to antiferromagnetic spin fluctuations. With further decreasing temperature (T⪡TN) a switching to a complex positive MD effect is found confirming additional contribution coming from the magnetic ordering. The present study underlines the importance of square-coordinated MnA″O2 units for generating MD coupling in an A′A″3B4O12-type structure; the magnitude of the MD effect then strongly depends on the precise chemical composition.
Comparison of the experimental, semi-experimental and ab initio equilibrium structures of acetylene: Influence of relativisitic effects and of the diagonal Born–Oppenheimer corrections
Authors: Liévin J. , Demaison J. , Herman M. , Fayt A. , Puzzarini C.
Published: February 2011

The equilibrium structure of acetylene (also named ethyne) has been reinvestigated to resolve the small discrepancies noted between different determinations. The size of the system as well as the large amount of available experimental data provides the quite unique opportunity to check the magnitude and relevance of various contributions to equilibrium structure as well as to verify the accuracy of experimental results. With respect to pure theoretical investigation, quantum-chemical calculations at the coupled-cluster level have been employed together with extrapolation to the basis set limit, consideration of higher excitations in the cluster operator, inclusion of core correlation effects as well as relativistic and diagonal Born–Oppenheimer corrections. In particular, it is found that the extrapolation to the complete basis set limit, the inclusion of higher excitations in the electronic-correlation treatment and the relativistic corrections are of the same order of magnitude. It also appears that a basis set as large as a core–valence quintuple-zeta set is required for accurately accounting for the inner-shell correlation contribution. From a pure experimental point of view, the equilibrium structure has been determined using very accurate rotational constants recently obtained by a “global analysis” (that is to say that all non-negligible interactions are explicitely included in the Hamiltonian matrix) of rovibrational spectra. Finally, a semi-experimental equilibrium structure (where the equilibrium rotational constants are obtained from the experimental ground state rotational constants and computed rovibrational corrections) has been obtained from the available experimental ground-state rotational constants for ten isotopic species corrected for computed vibrational corrections. Such a determination led to the revision of the ground-state rotational constants of two isotopologues, thus showing that structural determination is a good method to identify errors in experimental rotational constants. The three structures are found in a very good agreement, and our recommended values are rCC = 120.2958(7) pm and rCH = 106.164(1) pm.
Adlayer inhomogeneity without lateral interactions: Rationalizing correlation effects in CO oxidation at RuO2(110) with first-principles kinetic Monte Carlo
Authors: Matera Sebastian , Meskine Hakim , Reuter Karsten
Published: February 2011

Microkinetic modeling of surface chemical reactions still relies heavily on the mean-field based rate equation approach. This approach is expected to be most accurate for systems without appreciable lateral interactions among the adsorbed chemicals, and there in particular for the uniform adlayers resulting in poisoned regimes with predominant coverage of one species. Using first-principles kinetic Monte Carlo simulations and the CO oxidation at RuO2(110) as a showcase, we demonstrate that even in this limit mean-field rate equations fail to predict the catalytic activity by orders of magnitude. This deficiency is traced back to the inability to account for the vacancy pair formation that is kinetically driven by the ongoing reactions.
Very accurate potential energy curve of the LiH molecule
Authors: Tung Wei-Cheng , Pavanello Michele , Adamowicz Ludwik
Published: February 2011

We present very accurate calculations of the ground-state potential energy curve (PEC) of the LiH molecule performed with all-electron explicitly correlated Gaussian functions with shifted centers. The PEC is generated with the variational method involving simultaneous optimization of all Gaussians with an approach employing the analytical first derivatives of the energy with respect to the Gaussian nonlinear parameters (i.e., the exponents and the coordinates of the shifts). The LiH internuclear distance is varied between 1.8 and 40 bohrs. The absolute accuracy of the generated PEC is estimated as not exceeding 0.3 cm−1. The adiabatic corrections for the four LiH isotopologues, i.e., 7LiH, 6LiH, 7LiD, and 6LiD, are also calculated and added to the LiH PEC. The aforementioned PECs are then used to calculate the vibrational energies for these systems. The maximum difference between the computed and the experimental vibrational transitions is smaller than 0.9 cm−1. The contribution of the adiabatic correction to the dissociation energy of 7LiH molecule is 10.7 cm−1. The magnitude of this correction shows its importance in calculating the LiH spectroscopic constants. As the estimated contribution of the nonadiabatic and relativistic effects to the ground state dissociation energy is around 0.3 cm−1, their inclusion in the LiH PEC calculation seems to be the next most important contribution to evaluate in order to improve the accuracy achieved in this work.
Strong light extraction enhancement in GaInN light-emitting diodes by using self-organized nanoscale patterning of p-type GaN
Authors: Chhajed Sameer , Lee Wonseok , Cho Jaehee , Schubert E. Fred , Kim Jong Kyu
Published: February 2011

We report on a self-organized nanoscale patterning method by using oblique angle deposition to enhance the light extraction in a GaInN light-emitting diode (LED). The method offers one-step processing with good controllability of the feature size and density of the nanopatterns by varying the deposition angle during oblique angle deposition, eliminating the need for photolithography and annealing. A 5-nm-thick silver (Ag) film, when deposited by using oblique angle deposition, spontaneously forms a nanoscale island-like morphology on the substrate. This method is used to texture p-type GaN with nanoscale features, which results in increased light extraction from a GaInN LED. At 100 mA, the nanotextured LED shows a 46% higher light output than a standard LED with unpatterned (planar) p-type GaN.
Structural, electronic, and dynamical properties of methane under high pressure
Authors: Lin He , Li Yan-ling , Zeng Z. , Chen Xiao-jia , Lin H. Q.
Published: February 2011

The electronic structure and lattice dynamical properties of solid methane under high pressure have been studied based on density functional theory. We identify a cubic structure with space group of I\documentclass[12pt]{minimal}\begin{document}$\bar{4}$\end{document}4¯3m below 14 GPa, the Pmn21 structure in the range of 14–21 GPa, and the P21/c structure from 21 to 65 GPa. Our obtained Raman spectra of the P21/c structure agree well with the typical Raman active modes in the available experimental data. At 65 GPa, methane undergoes a phase transition from P21/c to Pnma. The structures with P21/c and Pnma symmetries are insulating, and under any pressure studied methane always remains in molecular form. For Pnma phase, the orientational ordering of CH4 molecules varies significantly at 79, 88, and 92 GPa, and by further increasing pressure the rotation of the molecules freezes and orientational ordering remains unchanged.
First-order thermal correction to the quadratic response tensor and rate for second harmonic plasma emission
Authors: Layden B. , Percival D. J. , Cairns Iver H. , Robinson P. A.
Published: February 2011

Three-wave interactions in plasmas are described, in the framework of kinetic theory, by the quadratic response tensor (QRT). The cold-plasma QRT is a common approximation for interactions between three fast waves. Here, the first-order thermal correction (FOTC) to the cold-plasma QRT is derived for interactions between three fast waves in a warm unmagnetized collisionless plasma, whose particles have an arbitrary isotropic distribution function. The FOTC to the cold-plasma QRT is shown to depend on the second moment of the distribution function, the phase speeds of the waves, and the interaction geometry. Previous calculations of the rate for second harmonic plasma emission (via Langmuir-wave coalescence) assume the cold-plasma QRT. The FOTC to the cold-plasma QRT is used here to calculate the FOTC to the second harmonic emission rate, and its importance is assessed in various physical situations. The FOTC significantly increases the rate when the ratio of the Langmuir phase speed to the electron thermal speed is less than about 3.
Optically nonactive assorted helix array with interchangeable magnetic/electric resonance
Authors: Xiong Xiang , Chen Xiao-Chun , Wang Mu , Peng Ru-Wen , Shu Da-Jun , Sun Cheng
Published: February 2011

We report here the design of an optically nonactive metamaterial by assembling metallic helices with different chiralities. With linearly polarized incident light, pure electric or magnetic resonance can be selectively realized, which accordingly leads to negative permittivity or negative permeability. Further, we show that pure electric or magnetic resonance can be interchanged at the same frequency band by merely changing the polarization of incident light for 90°. This design demonstrates a unique approach in constructing metamaterials.
Extraordinary infrared photoluminescence efficiency of Er0.1Yb1.9SiO5 films on SiO2/Si substrates
Authors: Wang X. J. , Wang B. , Wang L. , Guo R. M. , Isshiki H. , Kimura T. , Zhou Z.
Published: February 2011

Extraordinary infrared photoluminescence efficiency was found for Er2SiO5 film by optimizing the composition of Yb additions on SiO2/Si substrates. Above two orders of magnitude enhanced 1.53 μm Er3+ photoluminescence for the Er0.1Yb1.9SiO5 film on SiO2/Si substrate was obtained by pumping at 980 nm compared with pure Er2SiO5 film on Si substrate at 654 nm. All Er ions for Er0.1Yb1.9SiO5 film are optically active. The decreased nonradiative transient rate leads to extraordinary photoluminescence efficiency in the Er0.1Yb1.9SiO5 film. It indicated that the Er0.1Yb1.9SiO5 film is the sought candidate material for compact waveguide amplifiers and emitters in silicon photonics integration.
Three Asymmetrical Conjugated D-π-D' Sulfur-Containing Chromophores with a Focus on Two-Photon Absorption
Authors: Hu Zhang-Jun , Zhang Rui-Long , Sun Ping-Ping , Li Lin , Wu Jie-Ying , Yang Jia-Xiang , Tian Yu-Peng , Wang Chuan-Kui
Published: February 2011

Three novel asymmetrical D-π-D′ type sulfur-containing chromophores, (E)-4-(4-(benzylthio)styryl)-N,N-diethylbenzenamine (S1), (E)-4-(4-(tert-butylthio)styryl)-N,N-diethylbenzenamine (S2) and (E)-4-(4-(thio)styryl)-N,N-diethylbenzenamine (S3), were synthesized and characterized. Two kinds of substituents and hydrogen were introduced into the three different chromophores to investigate the influence of electron distribution on the sulfur atom. Meanwhile, a simple synthetic strategy of π-conjugated 4-(thio)styrene derivatives was performanced successfully. Linear and non-linear optical properties of S1, S2 and S3 were investigated both experimentally and theoretically. The optical properties indicate that they all have obvious characteristics of asymmetrical dipole molecules. The measured maximum two-photon cross-sections of S1–3 are 79, 57 and 19 GM (Goeppert-Mayer), respectively. It shows that the different substituents on the sulfur atom in molecules S1–3 lead to different electronic structures, which affect the optical properties. In these structures, the aromatic benzyl substituent (in S1) is superior for optimizing two-photon activity in the designed molecular framework.
Amino Acid-derived Protic Ionic Liquids: Physicochemical Properties and Behaviour as Amphiphile Self-assembly Media
Authors: Wang Jiayi , Greaves Tamar L. , Kennedy Danielle F. , Weerawardena Asoka , Song Gonghua , Drummond Calum J.
Published: February 2011

The thermal phase transitions and physicochemical properties of a series of 21 amino acid-derived protic ionic liquids and four protic molten salts have been investigated. Structure–property comparisons for this series were investigated for alkyl- and cyclic amino acid cations, and ethoxy and methoxy groups on the cation, combined with nitrate or various carboxylate-containing anions. All the protic fused salts were found to be ‘fragile’. Most of the protic fused salts exhibited a glass transition, with the transition temperatures ranging from –90° to –42°C. Viscosities and conductivities ranged from 0.03 to 15.46 Pa s and 0.02 to 2.20 mS cm–1 at 25°C respectively. The protic ionic liquids alanine methyl ester glycolate, proline methyl ester nitrate, and proline methyl ester glycolate were found to be capable of supporting amphiphile self-assembly. Lamellar or hexagonal liquid crystalline phases were observed with the cationic surfactant hexadecyltrimethylammonium bromide and the non-ionic surfactant Myverol 18–99K.
Photo-induced Energy Transfer in a Th-Symmetrical Hexakis-adduct of C60 Substituted with π-Conjugated Oligomers
Authors: Iehl Julien , Holler Michel , Nierengarten Jean-François , Yoosaf K. , Malicka Joanna M. , Armaroli Nicola , Delavaux-Nicot Béatrice
Published: February 2011

A stilbene derivative bearing a terminal alkyne unit has been prepared and grafted onto a Th‐symmetrical C60 hexakis‐adduct building block under alkyne/azide copper mediated Huisgen 1,3‐dipolar cycloaddition conditions. The photophysical properties of the resulting fullerene derivative surrounded by 12 conjugated oligomers have been investigated. Upon excitation of the peripheral chromophores, an efficient intramolecular energy transfer to the C60 core has been evidenced.
Covalent Functionalized Conjugated Dendrimers for Organic Light Emitting Diodes: Synthesis, Characterization, and the Deep Blue Electroluminescence
Authors: Zhou Yan , Ding Lin , Xiang Li-Ming , Pei Jian
Published: February 2011

Two deep blue-emitting dendrimers 11 and 12 with carbazole containing dendrons were developed in this contribution. The carbazole-containing units were introduced to tune the charge-transporting property of the desired dendrimers. The investigation of photophysical properties, electrochemical, and electroluminescence properties demonstrated that the balance between electron and hole transporting was achieved from both dendrimers. The preliminary organic light-emitting diode (OLED) fabrication achieved a pure blue colour with stable CIE chromaticity coordinates (X: 0.15–0.16, Y: 0.09–0.10) for 11 and 12. Single layer deep blue emitting diode devices with higher efficiency are achieved without the colour changing. The investigation of OLED performance indicates that dendrimers 11 and 12 are promising light-emitting materials with pure blue colour and good colour stability for OLEDs.
Covalently Cross-Linked Ferrocenyl PAMAMOS Dendrimer Networks
Authors: Herrero Marta , Losada José , García-Armada M. Pilar , Alonso Beatriz , Casado Carmen M.
Published: February 2011

Thin films of nanostructured organic–inorganic ferrocenyl–dendritic hybrid materials have been prepared by the sol-gel approach. The electrochemically active organometallic dendritic networks have been characterized by FT-IR and solid-state 29Si NMR spectroscopy and scanning electron microscopy. The thermal behaviour was investigated using thermogravimetric analysis and differential scanning calorimetry and the redox properties were studied by cyclic voltammetry and differential pulse voltammetry.
Toxoplasma gondii
sequesters centromeres to a specific nuclear region throughout the cell cycle
Authors: Brooks Carrie F. , Francia Maria E. , Gissot Mathieu , Croken Matthew M. , Kim Kami , Striepen Boris
Published: February 2011

Members of the eukaryotic phylum Apicomplexa are the cause of important human diseases including malaria, toxoplasmosis, and cryptosporidiosis. These obligate intracellular parasites produce new invasive stages through a complex budding process. The budding cycle is remarkably flexible and can produce varied numbers of progeny to adapt to different host-cell niches. How this complex process is coordinated remains poorly understood. Using
Toxoplasma gondii
as a genetic model, we show that a key element to this coordination is the centrocone, a unique elaboration of the nuclear envelope that houses the mitotic spindle. Exploiting transgenic parasite lines expressing epitope-tagged centromeric H3 variant CenH3, we identify the centromeres of
T. gondii
chromosomes by hybridization of chromatin immunoprecipitations to genome-wide microarrays (ChIP-chip). We demonstrate that centromere attachment to the centrocone persists throughout the parasite cell cycle and that centromeres localize to a single apical region within the nucleus. Centromere sequestration provides a mechanism for the organization of the
Toxoplasma
nucleus and the maintenance of genome integrity.
Searching for the missing baryons in clusters
Authors: Rasheed Bilhuda , Bahcall Neta , Bode Paul
Published: February 2011

Observations of clusters of galaxies suggest that they contain fewer baryons (gas plus stars) than the cosmic baryon fraction. This “missing baryon” puzzle is especially surprising for the most massive clusters, which are expected to be representative of the cosmic matter content of the universe (baryons and dark matter). Here we show that the baryons may not actually be missing from clusters, but rather are extended to larger radii than typically observed. The baryon deficiency is typically observed in the central regions of clusters (∼0.5 the virial radius). However, the observed gas-density profile is significantly shallower than the mass-density profile, implying that the gas is more extended than the mass and that the gas fraction increases with radius. We use the observed density profiles of gas and mass in clusters to extrapolate the measured baryon fraction as a function of radius and as a function of cluster mass. We find that the baryon fraction reaches the cosmic value near the virial radius for all groups and clusters above

. This suggests that the baryons are not missing, they are simply located in cluster outskirts. Heating processes (such as shock-heating of the intracluster gas, supernovae, and Active Galactic Nuclei feedback) likely contribute to this expanded distribution. Upcoming observations should be able to detect these baryons.
Transition from one-dimensional water to ferroelectric ice within a supramolecular architecture
Authors: Zhao Hai-Xia , Kong Xiang-Jian , Li Hui , Jin Yi-Chang , Long La-Sheng , Zeng Xiao Cheng , Huang Rong-Bin , Zheng Lan-Sun
Published: February 2011

Ferroelectric materials are characterized by spontaneous electric polarization that can be reversed by inverting an external electric field. Owing to their unique properties, ferroelectric materials have found broad applications in microelectronics, computers, and transducers. Water molecules are dipolar and thus ferroelectric alignment of water molecules is conceivable when water freezes into special forms of ice. Although the ferroelectric ice XI has been proposed to exist on Uranus, Neptune, or Pluto, evidence of a fully proton-ordered ferroelectric ice is still elusive. To date, existence of ferroelectric ice with partial ferroelectric alignment has been demonstrated only in thin films of ice grown on platinum surfaces or within microdomains of alkali-hydroxide doped ice I. Here we report a unique structure of quasi-one-dimensional (H
2
O)

12
n

wire confined to a 3D supramolecular architecture of

H
4
CDTA,
trans
-1,2-diaminocyclohexane-
N
,
N
,
N′
,
N′
-tetraacetic acid; 4,4′-bpy, 4,4′-bipyridine). In stark contrast to the bulk, this 1D water wire not only exhibits enormous dielectric anomalies at approximately 175 and 277 K, respectively, but also undergoes a
spontaneous
transition between “1D liquid” and “1D ferroelectric ice” at approximately 277 K. Hitherto unrevealed properties of the 1D water wire will be valuable to the understanding of anomalous properties of water and synthesis of novel ferroelectric materials.
Molecular vibration-sensing component in
Drosophila melanogaster
olfaction
Authors: Franco Maria Isabel , Turin Luca , Mershin Andreas , Skoulakis Efthimios M. C.
Published: February 2011

A common explanation of molecular recognition by the olfactory system posits that receptors recognize the structure or shape of the odorant molecule. We performed a rigorous test of shape recognition by replacing hydrogen with deuterium in odorants and asking whether
Drosophila melanogaster
can distinguish these identically shaped isotopes. We report that flies not only differentiate between isotopic odorants, but can be conditioned to selectively avoid the common or the deuterated isotope. Furthermore, flies trained to discriminate against the normal or deuterated isotopes of a compound, selectively avoid the corresponding isotope of a different odorant. Finally, flies trained to avoid a deuterated compound exhibit selective aversion to an unrelated molecule with a vibrational mode in the energy range of the carbon–deuterium stretch. These findings are inconsistent with a shape-only model for smell, and instead support the existence of a molecular vibration-sensing component to olfactory reception.
Loss of
cerebral cavernous malformation 3
(
Ccm3
) in neuroglia leads to CCM and vascular pathology
Authors: Louvi Angeliki , Chen Leiling , Two Aimee M. , Zhang Haifeng , Min Wang , Günel Murat
Published: February 2011

Communication between neural cells and the vasculature is integral to the proper development and later function of the central nervous system. A mechanistic understanding of the interactions between components of the neurovascular unit has implications for various disorders, including cerebral cavernous malformations (CCMs) in which focal vascular lesions form throughout the central nervous system. Loss of function mutations in three genes with proven endothelial cell autonomous roles,
CCM1/krev1 interaction trapped gene 1
,
CCM2
, and
CCM3/programmed cell death 10
, cause familial CCM. By using neural specific conditional mouse mutants, we show that
Ccm3
has both neural cell autonomous and nonautonomous functions.
Gfap
- or
Emx1
-Cre–mediated
Ccm3
neural deletion leads to increased proliferation, increased survival, and activation of astrocytes through cell autonomous mechanisms involving activated Akt signaling. In addition, loss of neural CCM3 results in a vascular phenotype characterized by diffusely dilated and simplified cerebral vasculature along with formation of multiple vascular lesions that closely resemble human cavernomas through cell nonautonomous mechanisms. RNA sequencing of the vascular lesions shows abundant expression of molecules involved in cytoskeletal remodeling, including protein kinase A and Rho-GTPase signaling. Our findings implicate neural cells in the pathogenesis of CCMs, showing the importance of this pathway in neural/vascular interactions within the neurovascular unit.
Phagosomal signaling byBorrelia burgdorferiin human monocytes involves Toll-like receptor (TLR) 2 and TLR8 cooperativity and TLR8-mediated induction of IFN-β
Authors: Cervantes Jorge L. , Dunham-Ems Star M. , La Vake Carson J. , Petzke Mary M. , Sahay Bikash , Sellati Timothy J. , Radolf Justin D. , Salazar Juan C.
Published: February 2011

PhagocytosedBorrelia burgdorferi(Bb) induces inflammatory signals that differ both quantitatively and qualitatively from those generated by spirochetal lipoproteins interacting with Toll-like receptor (TLR) 1/2 on the surface of human monocytes. Of particular significance, and in contrast to lipoproteins, internalized spirochetes induce transcription of IFN-β. Using inhibitory immunoregulatory DNA sequences (IRSs) specific to TLR7, TLR8, and TLR9, we show that the TLR8 inhibitor IRS957 significantly diminishes production of TNF-α, IL-6, and IL-10 and completely abrogates transcription of IFN-β in Bb-stimulated monocytes. We demonstrate that live Bb induces transcription of TLR2 and TLR8, whereas IRS957 interferes with their transcriptional regulation. Using confocal and epifluorescence microscopy, we show that baseline TLR expression in unstimulated monocytes is greater for TLR2 than for TLR8, whereas expression of both TLRs increases significantly upon stimulation with live spirochetes. By confocal microscopy, we show that TLR2 colocalization with Bb coincides with binding, uptake, and formation of the phagosomal vacuole, whereas recruitment of both TLR2 and TLR8 overlaps with degradation of the spirochete. We provide evidence that IFN regulatory factor (IRF) 7 is translocated into the nucleus of Bb-infected monocytes, suggesting its activation through phosphorylation. Taken together, these findings indicate that the phagosome is an efficient platform for the recognition of diverse ligands; in the case of Bb, phagosomal signaling involves a cooperative interaction between TLR2 and TLR8 in pro- and antiinflammatory cytokine responses, whereas TLR8 is solely responsible for IRF7-mediated induction of IFN-β.
Membrane-inlet mass spectrometry reveals a high driving force for oxygen production by photosystem II
Authors: Shevela Dmitriy , Beckmann Katrin , Clausen Jürgen , Junge Wolfgang , Messinger Johannes
Published: February 2011

Oxygenic photosynthesis is the basis for aerobic life on earth. The catalytic Mn
4
O

x

CaY

Z

center of photosystem II (PSII), after fourfold oxidation, extracts four electrons from two water molecules to yield dioxygen. This reaction cascade has appeared as a single four-electron transfer that occurs in typically 1 ms. Inevitable redox intermediates have so far escaped detection, probably because of very short lifetime. Previous attempts to stabilize intermediates by high O
2
-back pressure have revealed controversial results. Here we monitored by membrane-inlet mass spectrometry (MIMS) the production of

from
18
O-labeled water against a high background of

in a suspension of PSII-core complexes. We found neither an inhibition nor an altered pattern of O
2
production by up to 50-fold increased concentration of dissolved O
2
. Lack of inhibition is in line with results from previous X-ray absorption and visible-fluorescence experiments, but contradictory to the interpretation of previous UV-absorption data. Because we used essentially identical experimental conditions in MIMS as had been used in the UV work, the contradiction was serious, and we found it was not to be resolved by assuming a significant slowdown of the O
2
release kinetics or a subsequent slow conformational relaxation. This calls for reevaluation of the less direct UV experiments. The direct detection of O
2
release by MIMS shows unequivocally that O
2
release in PSII is highly exothermic. Under the likely assumption that one H
+
is released in the S
4
 → S
0
transition, the driving force at pH 6.5 and atmospheric O
2
pressure is at least 220 meV, otherwise 160 meV.
Anti-VEGF treatment reduces blood supply and increases tumor cell invasion in glioblastoma
Authors: Keunen Olivier , Johansson Mikael , Oudin Anaïs , Sanzey Morgane , Rahim Siti A. Abdul , Fack Fred , Thorsen Frits , Taxt Torfinn , Bartos Michal , Jirik Radovan , Miletic Hrvoje , Wang Jian , Stieber Daniel , Stuhr Linda , Moen Ingrid , Rygh Cecilie Brekke , Bjerkvig Rolf , Niclou Simone P.
Published: February 2011

Bevacizumab, an antibody against vascular endothelial growth factor (VEGF), is a promising, yet controversial, drug in human glioblastoma treatment (GBM). Its effects on tumor burden, recurrence, and vascular physiology are unclear. We therefore determined the tumor response to bevacizumab at the phenotypic, physiological, and molecular level in a clinically relevant intracranial GBM xenograft model derived from patient tumor spheroids. Using anatomical and physiological magnetic resonance imaging (MRI), we show that bevacizumab causes a strong decrease in contrast enhancement while having only a marginal effect on tumor growth. Interestingly, dynamic contrast-enhanced MRI revealed a significant reduction of the vascular supply, as evidenced by a decrease in intratumoral blood flow and volume and, at the morphological level, by a strong reduction of large- and medium-sized blood vessels. Electron microscopy revealed fewer mitochondria in the treated tumor cells. Importantly, this was accompanied by a 68% increase in infiltrating tumor cells in the brain parenchyma. At the molecular level we observed an increase in lactate and alanine metabolites, together with an induction of hypoxia-inducible factor 1α and an activation of the phosphatidyl-inositol-3-kinase pathway. These data strongly suggest that vascular remodeling induced by anti-VEGF treatment leads to a more hypoxic tumor microenvironment. This favors a metabolic change in the tumor cells toward glycolysis, which leads to enhanced tumor cell invasion into the normal brain. The present work underlines the need to combine anti-angiogenic treatment in GBMs with drugs targeting specific signaling or metabolic pathways linked to the glycolytic phenotype.