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A set of seven structurally related Sm proteins forms the core of the snRNP particles containing the spliceosomal U1, U2, U4 and U5 snRNAs. A search of the genomic sequence of Saccharomyces cerevisiae has identified a number of open reading frames that potentially encode structurally similar proteins termed Lsm (L¯ike Sm¯) proteins. With the aim of analysing all possible interactions between the Lsm proteins and any protein encoded in the yeast genome, we performed exhaustive and iterative genomic two-hybrid screens, starting with the Lsm proteins as baits. Indeed, extensive interactions amongst eight Lsm proteins were found that suggest the existence of a Lsm complex or complexes. These Lsm interactions apparently involve the conserved Sm domain that also mediates interactions between the Sm proteins. The screens also reveal functionally significant interactions with splicing factors, in particular with Prp4 and Prp24, compatible with genetic studies and with the reported association of Lsm proteins with spliceosomal U6 and U4/U6 particles. In addition, interactions with proteins involved in mRNA turnover, such as Mrt1, Dcp1, Dcp2 and Xrn1, point to roles for Lsm complexes in distinct RNA metabolic processes, that are confirmed in independent functional studies. These results provide compelling evidence that two-hybrid screens yield functionally meaningful information about protein–protein interactions and can suggest functions for uncharacterized proteins, especially when they are performed on a genome-wide scale.

We demonstrate temporal pulse compression in gas-filled kagomé hollow-core photonic crystal fiber (PCF) using two different approaches: fiber-mirror compression based on self-phase modulation under normal dispersion, and soliton effect self-compression under anomalous dispersion with a decreasing pressure gradient. In the first, efficient compression to near-transform-limited pulses from 103 to 10.6 fs was achieved at output energies of 10.3 μJ. In the second, compression from 24 to 6.8 fs was achieved at output energies of 6.6 μJ, also with near-transform-limited pulse shapes. The results illustrate the potential of kagomé-PCF for postprocessing the output of fiber lasers. We also show that, using a negative pressure gradient, ultrashort pulses can be delivered directly into vacuum.

Au sein de l'Universite du Maine, pour plusieurs modules, une methode d'evaluation par passage de ceintures est proposee aux etudiants en lieu et place d'un examen terminal. S'inscrivant dans une demarche d'evaluation a la fois certifiante et formative, respectant le rythme d'acquisition de chacun, les modalites de creation et de fonctionnement des ceintures montrent que la validation progressive par ceintures est securisante. Les auteurs, tous enseignants, donnent leur reactions et points de vues, et interpretent les reactions et les points de vues de l'institution et des etudiants. Un bilan chiffre sur deux annees des choix et strategies des etudiants sont presentes.

We present a simple refractive index sensor based on a step-index fiber with a hollow micro-channel running parallel to its core. This channel becomes waveguiding when filled with a liquid of index greater than silica, causing sharp dips to appear in the transmission spectrum at wavelengths where the glass-core mode phase-matches to a mode of the liquid-core. The sensitivity of the dip-wavelengths to changes in liquid refractive index is quantified and the results used to study the dynamic flow characteristics of fluids in narrow channels. Potential applications of this fiber microstructure include measuring the optical properties of liquids, refractive index sensing, biophotonics and studies of fluid dynamics on the nanoscale.

We investigate numerically and experimentally the propagation of visible sub-50 fs pulses in a tapered small core photonic crystal fiber. The fiber has anomalous dispersion between two closely spaced zero dispersion wavelengths at 509 and 640 nm, and the excitation wavelength was varied within this range. We find that the spectral evolution in the low power regime is dominated by higher-order soliton fission, soliton self-frequency shift, and dispersive wave generation. At higher powers, extremely wide spectral broadening of the input pulse occurs within the first few millimeters of fiber. The wavelength conversion into the blue and red spectral ranges is studied as a function of the input power and excitation wavelength. Conversions into the spectral range 300-470 nm at efficiencies as high as 40% are observed when pumping at 523 nm.

iMERA/Euromet Project 885 is co-ordinating European effort towards a new determination of the Boltzmann constant kB to within 1 ppm with the aim of redefining the unit of thermodynamic temperature. This project will enable the National Physical Laboratory to perform primary thermometry in the region of −40 °C (Hg) to 156 °C (In) with sub-millikelvin uncertainties by 2012. The chosen technique relies on determining the speed of sound in a monatomic gas. Using the radial acoustic modes of a spherical resonator, consisting of a copper shell and filled with argon or helium, the speed of sound can be measured with great precision and from this measurement the Boltzmann constant can be inferred. This project draws on expertise in dimensional, density, microwave and acoustic measurements at the state-of-the-art. In order to gain further understanding of the experimental configuration a vibro-acoustic model has been developed using the finite element method. Initial calculations were carried out to ensure that predictions of the resonant frequency could be made with the required precision by comparing against an analytical model of a spherical shell filled with a gas. A more elaborate model better representing the experimental configuration was then developed. Thermo-viscous effects close to the fluid-structure boundary were accounted for using a linear acoustic formulation, from which a normal incidence admittance boundary condition was derived and imposed on the inner surface of the resonator. Acoustic pressure, particle velocity and temperature variation as a function of position may be obtained within the gas as a function of frequency. It is therefore possible to investigate how changes in the configuration affect the frequency of radial modes. It is hoped that this approach will shed a better understanding of the underlying complex physical phenomena allowing a minimization of the overall uncertainty.

The acoustic wave propagation in thermoviscous fluid can generate slow phenomena, such as streaming and thermoacoustic effects, by nonlinear processes localised mainly in the viscous and thermal boundary layers. The model presented consists in computing numerically by the finite element method, (i) first, the harmonic solution for linear acoustics in thermoviscous fluid including the boundary layers, and (ii) second, the unsteady solution for the acoustic streaming and heat transfer. The model formulation is based on the mass and momentum conservation equations for the streaming, and the energy conservation equation for heat transfer. The streaming is presented as a standard form of an incompressible flow for velocity vector for mass transport, where the nonlinear effects of acoustics are considered as excitation forces for the streaming and sources for heat transfer. As the performance of thermoacoustic devices is limited by the convective heat transfer of the streaming, this study is suited for the opti...

A numerical methodology is presented to compute the acoustic field in a closed domain filled by a thermoviscous fluid, using the finite element method. The formulation based upon temperature variation and particle velocity is well suited for both (i) modelling the acoustic, thermal and viscous effects in the fluid bulk and (ii) accounting for the non‐slip and thermal boundary conditions on the solid. The set of coupled equations presents usual scalar‐ and vector‐ operators for finite element modelling. Due to the development of thin thermal‐ and viscous‐ boundary layers compared to the acoustic wavelength, very different scales are present in the computed fields: the finite‐element mesh needs to be dramatically refined along the direction normal to the boundary, while a coarse mesh is often sufficient along the directions parallel to the boundary, and far from the boundaries. The optimised mesh is obtained iteratively, using a loop procedure computing (a) the thermoviscous solution, (b) the metric map suited for this field, and (c) the unstructured anisotropic adapted mesh based on this metric, until convergence. Results are presented for two‐dimensional and axisymmetric three‐dimensional applications, illustrating thermoviscous effects for various geometries of cavities.

Isatin derivatives exhibit significant biological, medicinal and pharmacological activities, [1,2] such as antituberculous, antihypoxing agent, anticonvulsant, antihyperglycemic; active against salmonella, typhi and against vibrio cholerae. Besides, they are used in treating and preventing pestvirus.[...]

We demonstrate experimentally the formation and stable propagation of bound soliton pairs in a highly nonlinear photonic crystal fiber. The bound pairs occur at a particular power as the consequence of high-order soliton fission. They propagate over long distances with constant inter-soliton frequency and time separation. During propagation, the soliton self-frequency shift causes the central frequency of the pairs to move towards longer wavelength. The formation and characteristics of the bound soliton pairs are confirmed numerically. We believe this to be the first experimental observation of such bound soliton pairs. © 2007 Optical Society of America.

We demonstrate a Raman laser made from a grating-free highly-nonlinear photonic crystal fiber. The laser threshold power is lower than 600 mW and laser power characteristics recorded in experiments are accurately described from the usual simplest model dealing only with stationary evolutions of total optical powers [J. Opt. Soc. Am. 69, 803-807 (1979)]. In our theoretical treatment, reflectivity coefficients are fixed parameters, in strong contrast with procedures usually implemented to describe Raman fiber lasers made with fiber Bragg gratings. Experimental investigations of the spectral properties of our grating-free Raman fiber laser evidence that the shape of the Stokes power spectrum remains remarkably Gaussian whatever the incident pump power. Increasing the incident pump power induces a drift of the Stokes wavelength together with a broadening of the Stokes optical spectrum. Investigations on the role of light polarization on laser characteristics show that our grating-free Raman fiber laser behaves as a Raman laser made with a standard polarization maintaining fiber.

Progress in nonlinear optics is allowing expansion of development in ultrafast broadband and ultraviolet sources.

Polarization modulation instability (PMI) in birefringent photonic crystal fibers has been observed in the normal dispersion regime with a frequency shift of 64 THz between the generated frequencies and the pump frequency. The generated sidebands are orthogonally polarized to the pump. From the observed PMI frequency shift and the measured dispersion, we determined the phase birefringence to be 5.3 x 10(-5) at a pump wavelength of 647.1 nm. This birefringence was used to estimate the PMI gain as a function of pump wavelength. Four-wave mixing experiments in both the normal and the anomalous dispersion regimes generated PMI frequency shifts that show good agreement with the predicted values over a 70 THz range. These results could lead to amplifiers and oscillators based on PMI.

The conversion of light fields in photonic crystal fibers (PCFs) capitalizes on the dramatic enhancement of several optical nonlinearities. We present here spectrally smooth, highly broadband supercontinuum radiation in a short piece of high-nonlinearity soft-glass PCF. This supercontinuum spans several optical octaves, with a spectral range extending from 350 nm to beyond 3000 nm. The selection of an appropriate propagation-length determines the spectral quality of the supercontinuum generated. Experimentally, we clearly identify two regimes of nonlinear pulse transformation: when the fiber length is much shorter than the dispersion length, soliton propagation is not important and a symmetric supercontinuum spectrum arises from almost pure self-phase modulation. For longer fiber lengths the supercontinuum is formed by the breakup of multiple Raman-shifting solitons. In both regions very broad supercontinuum radiation is produced.

We describe the fabrication and characterization of a free-standing silica glass membrane waveguide formed using fiber fabrication processes. The membrane has a thickness of 0.6 microm and a width of 60 microm and is many meters long. The optical attenuation is measured as 0.4 dB/m. Such attenuation outperforms that of conventional planar waveguides by several orders of magnitude.

We report a new method for making low-loss interfaces between conventional single-mode fibers and photonic crystal fibers (PCFs). Adapted from the fabrication of PCF preforms from stacked tubes and rods, this method avoids the need for splicing and is versatile enough to interface to virtually any type of index-guiding silica PCF. We illustrate the method by forming interfaces to two problematic types of PCF, highly nonlinear and multicore. In particular, we believe this to be the first method capable of individually coupling light into and out of all the cores of a fiber with multiple closely spaced cores, without input or output cross talk.

The synthesis and the characterization of new isatin derivatives obtained by 1,3-dipolar cycloaddition reactions on allylisatin and propargylisatin are described. The products thus regiospecifically obtained in good yields bear oxadiazolyles or trizolyles groups, and were characterized by FT-IR spectroscopy, NMR spectroscopy and mass spectrometry.

Light-plasma interactions are explored in gas-filled photonic crystal fibers through self-compression of few-μJ pulses. Here we study the interaction between ionization-driven soliton dynamics and Kerr-based deep-UV generation.

An efficient and tunable 200–600 nm source based on resonant radiation from ultrafast solitons in gas-filled hollow-core PCF is demonstrated. The influence of axially varying dispersion, controlled with a pressure gradient, is also explored.

We review the use of hollow-core photonic crystal fibers (PCFs) in the field of ultrafast gas-based nonlinear optics, including recent experiments, numerical modeling, and a discussion of future prospects. Concentrating on broadband guiding kagome-style hollow-core PCF, we describe its potential for moving conventional nonlinear fiber optics both into extreme regimes—such as few-cycle pulse compression and efficient deep ultraviolet wavelength generation—and into regimes hitherto inaccessible, such as single-mode guidance in a photoionized plasma and high-harmonic generation in fiber.

We show theoretically that spontaneous symmetry breaking can occur in a temporally inversion-symmetric system consisting of a photonic crystal fiber ring cavity synchronously pumped by ultrashort optical pulses.

International audience; In this study, polyphenols have been extracted from solid residues and leaves of olive tree (Olea europaea L) in order to assess this vegetable biomass by evaluation of their capacity as a natural antioxidants. The anti-oxidative activity was tested by addition of these extracts on commercial olive oil samples. The olive oil stability has been measured by accelerated oxidation under a simulated storage conditions (60°C/15 days). The change in the oxidation state was followed by measuring of the free acidity, peroxide value (PV) and the specific extinction at 270 nm. The assessment of enriched oils showed that polyphenols from olive by-products play a key role in reducing of oxidative deterioration of the oil. The results suggest the introduction of olive leaves and solid residues extracts in food preparation, both during storage or heating food, for better preservation.

We demonstrate that timing jitter has a strong influence on supercontinua generated in a photonic crystal fiber ring cavity synchronously pumped by 140 fs pulses. The global dynamics with respect to cavity detuning is analyzed both numerically and experimentally by tracking the cavity pulse energy. The results show that low-frequency timing jitter, induced by both the pump oscillator and the external cavity, masks the fine underlying bifurcation structure of the system. Numerical simulations in the absence of timing jitter reveal that the system dynamics fall into four qualitatively different regimes. The existence of these regimes is experimentally observed in first-return diagrams.

We numerically investigate the effect of ionization on ultrashort high-energy pulses propagating in gas-filled kagome-lattice hollow-core photonic crystal fibers by solving an established uni-directional field equation. We consider the dynamics of two distinct regimes: ionization induced blue-shift and resonant dispersive wave emission in the deep-UV. We illustrate how the system evolves between these regimes and the changing influence of ionization. Finally, we consider the effect of higher ionization stages.

We report the experimental demonstration of a passively mode-locked Er-doped fiber ring laser operating at the 337th harmonic (1.80 GHz) of the cavity. The laser makes use of highly efficient Raman-like optoacoustic interactions between the guided light and gigahertz acoustic resonances trapped in the micron-sized solid glass core of a photonic crystal fiber. At sufficient pump power levels the laser output locks to a repetition rate corresponding to the acoustic frequency. A stable optical pulse train with a side-mode suppression ratio higher than 45 dB was obtained at low pump powers (~60 mW).

The influence of timing jitter on supercontinua generated in a photonic crystal fiber ring cavity is experimentally demonstrated and numerically modeled. Periodic oscillations of the cavity pulses occur between a discrete set of spectral states.

Detailed numerical and experimental studies of propagation of 110 fs laser pulses at 800 nm in small-core photonic crystal fibers (γ≈100 W-1 km−1) reveal that pulse breakup occurs in two distinct regimes defined by the input power. At low peak power (soliton order N≤7) higher-order soliton fission occurs: individual solitons being ejected from the input pulse one after the other and are arranged in wavelength and in time by peak power. At higher levels of peak power (N>8), pulse breakup results in ejection of bound soliton pairs and the formation of single solitons that collide during propagation.

1 Laboratoire de Chimie Organique Heterocyclique, Pole de competences Pharmacochimie UniversiteMohammed V-Agdal, BP: 1014 Avenue Ibn Batouta, Rabat, Morroco2 Blood-Brain Barrier Laboratory (EA 2465), IUT of Bethune, University of Artois, BP 819, F-62408Bethune*Author to whom correspondence should be addressed.. E-mail: emessassi@yahoo.fr

High-energy, single-mode, coherent, ultrafast pulses of light - tunable from the vacuum-UV to the visible spectral region - can be generated in gas-filled hollow-core photonic-crystal fibers through a simple experimental scheme.

We present new equations describing pulse envelope propagation in a hollow-core PCF filled with an ionizable gas. We describe for the first time the recently observed plasma-induced soliton self-frequency blueshift.

Recent PCF developments include optoacoustic high harmonic mode-locking of fibre lasers, twist-induced guidance in coreless PCF, “swimming” microparticle lasers in liquid-filled PCF and ultrashort wavelength-tunable DUV and VUV pulses from gas-filled hollow-core PCF.

Benzodiazepinic compounds such as Clobazam (1)(Scheme 1) are used as anxiolitics, anticonvulsants,myorelaxants and sedatives [1-6]. Similar biological activ-ities have also been observed for 7-chloro-1,5-di-N-allyl-1,5-benzodiazepin-2,4-dione (2) (Scheme 1) [7-8].In order to increase the water solubility of 1,4-benzodi-azepine analogues, we have previously linked hydrophilicsugar residues to various hydrophobic 1,4-benzodiazepin-2,5-diones and 1,4-benzodiazepin-5,11-diones [9-10].The aim of this study was to synthesize glucosyl-1,5-benzodiazepin-2,4-diones of the type 3(Scheme 1), inwhich both N-1 and N-5 are attached to either a partiallyprotected glucofuranosyl moiety, as in 6, or a 6-deoxy-D-glucopyranos-6-yl group as in 7 (Scheme 2).Results and Discussion.The starting material, 1,5-benzodiazepin-2,4-dione (4)was prepared by condensing malonic acid with 1,2-diaminobenzene in hydrochloric acid [11-13].Refluxing of 1,5-benzodiazepin-2,4-dione 4with 5,6-anhydro-1,2-O-isopropylidene-α-D-glucofuranose (5a)[14] for 2 hours in the presence of K

Continuous-wave and quasi-cw operation of tunable optical parametric generation has been demonstrated in a photonic-crystal fiber. The frequency shift of the generated sidebands, which arise from modulation instability, depends strongly on the detuning of the pump from the fiber’s zero-dispersion wavelength. Over 30 nm of sideband tunability has been demonstrated using a 300 mW cw pump, and over 185 nm of tunability using a 1.6 W quasi-cw pump. Continuous wave and quasi-cw pumps eliminate the detrimental effects of pump–sideband walk-off. In the absence of walk-off it is the fluctuations in the index profile of the photonic-crystal fiber along its length that limit the tunable sideband range.

The propagation dynamics of an ultrashort optical pulse near the second zero-dispersion point of a small-core high-delta photonic crystal fiber is investigated using cross-correlation frequency-resolved optical gating. Negative dispersion slope strongly influences the observed behavior.

We report on the observation of cross-phase modulation instability in a highly nonlinear photonic crystal fiber. In such fibers the presence of higher orders of dispersion results in a complex phase-matching curve. We are able to observe this behavior experimentally and obtain excellent agreement between the measured and predicted shifts.

Nonlinear dynamics of ultrashort optical pulses in the vicinity of the second zero-dispersion point of a small-core photonic crystal fiber is visualized and studied using cross-correlation frequency-resolved optical gating. New spectral features observed in the experiments match well with recent theoretical predictions of the generation of new frequencies via mixing of solitons and dispersive waves. Power- as well as length-dependent dynamics is obtained showing strong interaction between solitons and dispersive waves, soliton-soliton interaction, soliton stabilization against Raman self-frequency shift and Cherenkov continuum generation.

We demonstrate the use of a large-pitch Kagome-lattice hollow-core photonic crystal fiber probe for Raman spectroscopy. The large transmission bandwidth of the fiber enables both the excitation and Raman beams to be transmitted through the same fiber. As the excitation beam is mainly transmitted through air inside the hollow core, the silica luminescence background is reduced by over 2 orders of magnitude as compared to standard silica fiber probes, removing the need for fiber background subtraction.

We report the observation of self-oscillations of the output power in a cascaded Raman fiber laser delivering two Stokes components. Our cascaded Raman fiber laser is made with a highly nonlinear photonic crystal fiber and it oscillates within a Perot-Fabry cavity formed by weak Fresnel reflections from the fiber ends. From our experimental and theoretical study, we identify stimulated Raman scattering as being the physical effect dominant in the emergence of unstable behaviors inside the Perot-Fabry cavity. Mechanisms of laser destabilization are thus found to be very different from polarization mechanisms previously identified as being responsible for unstable behaviors in conventional one-stage Raman fiber lasers [14, 15].

The effective Kerr nonlinearity of hollow-core kagome-style photonic crystal fiber (PCF) filled with argon gas increases to ~15% of that of bulk silica glass when the pressure is increased from 1 to 150 bar, while the zero dispersion wavelength shifts from 300 to 900 nm. The group velocity dispersion of the system is uniquely pressure-tunable over a wide range while avoiding Raman scattering-absent in noble gases-and having an extremely high optical damage threshold. As a result, detailed and well-controlled studies of nonlinear effects can be performed, in both normal and anomalous dispersion regimes, using only a fixed-frequency pump laser. For example, the absence of Raman scattering permits clean observation, at high powers, of the interaction between a modulational instability side-band and a soliton-created dispersive wave. Excellent agreement is obtained between numerical simulations and experimental results. The system has great potential for the realization of reconfigurable supercontinuum sources, wavelength convertors and short-pulse laser systems.

A nanoscale hole placed centrally in the core of a PCF breaks the degeneracy between radially and azimuthally polarized modes, causing a large splitting in phase velocity, group velocity and dispersion.

Raman-like forward scattering by acoustic phonons transversely trapped in birefringent silica-air photonic crystal fibers is studied. As the air-filling fraction increases, core-confined acoustic resonances become increasingly apparent at higher frequencies (>1.1 GHz), while the number of cladding-confined acoustic modes involved in scattering falls. Two main types of scattering are observed: intramodal (scattering to new frequencies within the same optical mode) and intermodal (frequency-shifted scattering to a different optical mode). It is shown that the twofold symmetric microstructure in a birefringent fiber causes strongly polarization-dependent intramodal scattering. Good agreement is obtained between the experimental measurements and numerical solutions of both the acoustic and electromagnetic wave equations by using a full-vectorial finite-element approach. Phononic bandgaps are found to play a significant role at higher air-filling fractions, leading to the appearance of additional bands in the scattering spectrum.

Photonic crystal fibres exhibiting endlessly single-mode operation and dispersion zero in the range 1040 to 1100 nm are demonstrated. A sub-ns pump source at 1064 nm generates a parametric output at 732 nm with an efficiency of 35%, or parametric gain of 55 dB at 1315 nm. A broad, flat supercontinuum extending from 500 nm to beyond 1750 nm is also demonstrated using the same pump source.

We propose a feedback technique for obtaining stable mode-locked operation in lasers that would normally exhibit Q switching. Using the Haus model with population dynamics, we examine numerically the case in which the intensity is monitored by a slow detector and fed back to the pump power after electronic derivation. This approach allows elimination of Q switching in all situations considered, in particular, in lasers with a long upper-state lifetime.

Summary form only given. Gas-filled kagome-lattice hollow core photonic crystal fibre (HC-PCF) is attractive for nonlinear optical experiments, offering a broad transmission window, a high damage threshold and low loss compared to capillaries [1]. Its dispersion is uniquely low and smooth from the UV to the IR and can be tuned simply by varying the gas pressure. Recently we demonstrated tuning of the zero dispersion wavelength (ZDW) from 300 to 900 nm in an argon-filled kagome HC-PCF by varying the gas pressure from 1 to 150 bar [2]. The concomitant increase in density brings the nonlinearity to within an order of magnitude of that of fused silica. Nonlinear effects such as the generation of tunable deep-UV light via dispersive wave emission, and the observation of blue-shifting solitons due to ionization effects, can be observed in these fibres. Since both these phenomena rely on soliton pulse compression to achieve high peak intensities (which can be as high as 1015 W/cm2), the dispersion must be anomalous at the pump laser wavelength (800 nm, pulse duration 150 fs) [3]. At the high gas densities reported in this paper, however, the normal dispersion of the gas dominates over the weaker anomalous dispersion of the kagome fibre.Interestingly, the supercritical regime can be reached at room temperature in xenon (critical point 16°C and 58 bar) [2,4]. In this thermodynamic regime, liquids and gases are no longer distinguishable. As the gas pressure is increased from 25 to 35 bar (fibre length 28 cm, core diameter 18 μm), spectral broadening is observed up to the energy corresponding to self-focusing in the input cell, at which point the coupling is impaired (Fig. 1). The sharp spectral transitions (shown by red arrows) are indicative of this coupling limitation, the self-focusing threshold dropping with increasing gas pressure and nonlinearity. At 25 bar a UV band at ~340 nm forms by intermodal fourwave-mixing (iFWM), near-field imaging showing the UV light to be in HE12 mode. Numerical simulations confirm the experimental results of both self-focusing and iFWM. In the supercritical regime at 80 bar, distinct spectral broadening by self-phase modulation was observed as the launched pulse energy was increased from 15 to 60 nJ. Kagome HC-PCF filled with Xe at high pressure uniquely allows one to study ultrafast dynamics in the absence of Raman scattering at nonlinearity levels as high as silica, while offering pressure-controllable dispersion.