Cold Crystals Research Articles

Cold and Liquid Crystal Properties of Square-Planar Copper(II) Versus Nickel(II)- Iminophenolate/Naphthalen-2-Olate Schiff Base Complexes.

Reaction of the phenolate or naphthalen-2-olate based Schiff base ligands, (E)-1-((2-ethylphenylimino)methyl)phenol (HL1) or (E)-1-((2-ethylphenylimino)methyl)naphthalen-2-ol (HL2) with nickel(II) and copper(II) acetate provides the complexes bis[(E)-1-((2-ethylphenylimino)methyl)phenolato-ĸ2N,O]Ni/Cu(II), [Ni(L1)2] (1) and [Cu(L1)2] (2), or bis[(E)-1-((2-ethylphenylimino)methyl)naphthalen-2-olato-ĸ2N,O]Ni/Cu(II), [Ni(L2)2] (3) and [Cu(L2)2] (4), respectively. Single crystal X-ray structure determinations for 1, 3 and 4 reveal N2,O2-metal coordination of two chelating Schiff base ligands in a square-planar geometry. Powder X-ray diffractograms confirm the phase purity of the bulk microcrystalline samples. Thermal analyses by differential scanning calorimetry (DSC) and polarized light microscopic (PLM) indicate the copper(II) complexes to exhibit cold crystal (2) and liquid crystal (4) property. Cyclic voltammograms suggest an irreversible electrochemical process with two one electron charge transfer processes in N,N-dimethylformamide. Variable temperature magnetic measurements at the solid-state prove the diamagnetic nature of the low-spin Ni2+ centres in 1 or 3, as expected from the square-planar coordination geometry with rather strong ligands. The complexes expose medium level of antioxidant activity in methanol. Optimized geometry and excited state property by DFT/TD-DFT correspond well to the experimental results of the electronic and molecular structure at the ground state.

Design of micro-jet plasma system: a novel nanoparticles manufacturing method in atmospheric pressure

Micro jet atmospheric (MPJ) plasma was first utilized to create nano-sized crystals. Nanosized particles may have advantageous characteristics such as better internal quality and dissolving rates of the product compared to traditional crystalline goods. A nebulizer system sprays an aerosol solution into plasma by use of a carrier gas in a cold plasma crystal (argon). The plasma warms and loads the droplets causing solvent and columbic fission evaporation, and then the nucleation and crystal formation start within the limited volume given by the tiny drops. This produces nano-sized crystals. MPJ was used to establish the operating parameters for producing nano-sized ZnSe material crystals using electron microscope transmitting and X-ray powder diffraction tests as well as sensitivity testing have been carried out. Sensitivity tests showed lower friction sensitivity for the nano-scale product, suggesting a better internal quality of the crystal product.

The role of crystal mush in porphyry systems: A case study from the Baishiya ore field, East Kunlun orogenic belt, northern Qinghai-Tibet plateau

Since a cold storage crystal mush reservoir has been gradually used to describe magmas in shallow crust, traditional mechanisms, such as wall-rock assimilation, melt-crystal separation, as well as magma mixing and mingling, must be used with caution because recycled antecrysts can play a significant role. As a result, magmatic processes accounted for texture, geochemistry, and mineralization diversity among ore-related porphyry, overlying (sub)volcanic rocks, and underlying pluton in porphyry systems remain ambiguous. The Baishiya igneous suite (East Kunlun orogenic belt, China) with porphyry-related skarn mineralization provides an opportunity to resolve this issue. Within the crystal mush concept, we propose a comprehensive model based on the subtle changes. First and foremost, large K-feldspar grains characterized by high Sr/Y ratios (52–134) in the top area of granodiorite have a slightly enriched lead isotopic signature, indicating a previously existed crystal mush equilibrated with K-feldspar. The locked crystal mush was injected by mantle-derived mafic melts, leading to a transfer in heat and volatiles from hot melts to cold crystal mush. The buoyant volatiles and loaded metals introduced by episodic mafic replenishments concentrated on the roof, providing a fluid-rich and thermal cycling condition for K-feldspar coarse graining. Some enlarged K-feldspar grains sunk into the bottom area due to gravity, and subsequently reacted with upwelling hot melts to form rapakivi textures. As a gradually waning of injection of mafic melts, crystallization drove fluid exsolution, forming magmatic-hydrothermal events. The finally solidified granodiorite acted as a host rock for a newly produced magma reservoir, but the following development was different. Catastrophic eruptions induced by tectonic stress transition led to a strong depletion of volatiles and associated metal endowment in the underlying magma reservoir, and subsequently left a barren magma source, terminating potential mineralization events. The residual felsic melts migrated upwards along previously formed magma conduits, and thus emplaced as barren porphyry dike. Our work reveals that recycling of K-feldspar antecryst induced by mafic injection contributes to high Sr/Y ratio in ore-related porphyritic granodiorite. Within a long-lived replenishment of mantle-derived magma, a crystal mush reservoir at shallow crustal levels can act as a ‘cooling pond’ to quench these hot melts, but accept volatiles and loaded ore-forming elements, concentrating metals by volatile buoyancy with the help of a compressional stress, which is presumably essential for late fluid exsolution from the reservoir’s roof.

Cold Crystallization and the Molecular Structure of Imidazolium-Based Ionic Liquid Crystals with a p-Nitroazobenzene Moiety.

The cold crystallization mechanism of 1-{[4′-(4″-nitrophenylazo)phenyloxy]}hexyl-3-methyl-1H-imidazol-3-ium tetrafluoroborate ionic liquid crystal was investigated based on thermal analysis, structural analysis, infrared spectroscopy, and quantum chemical calculations. By conducting thorough structural characterization, we found that the prerequisite for cold crystallization is the irreversible molecular conformational alteration induced by the initial heating of the as-grown crystal into a smectic liquid crystal. The originally linear cation molecule bends and forms a step-stair conformation that persists throughout the subsequent heating and cooling processes as phase transition occurs from the crystal phase to the liquid crystal phase and then to the isotropic liquid phase. The formation of cold crystal occurs because of the choice of molecular stability over crystalline stability. Given the exothermic anomaly exhibited upon heating generic crystals to cold crystals, these findings demonstrate the promising potential of this ionic liquid crystal for thermal energy storage applications.

Light yield of cold undoped CsI crystal down to 13 keV and the application of such crystals in neutrino detection

The light yield of an undoped CsI crystal at about 77 Kelvin was measured to be 33.5 , pm , 0.7 photo-electrons (PE) per keV electron-equivalent (keVee) in the energy range of [13, 60] keVee using X and gamma -rays from an ^{241}Am radioactive source. Based on this experimental result, the performance of 10 kg cryogenic inorganic scintillating crystals coupled to SiPM arrays to probe non-standard neutrino interactions through the detection of coherent elastic neutrino-nucleus scatterings at the spallation neutron source, Oak Ridge National Laboratory, was examined in detail.

Affective Materialities: Reorienting the Body in Modernist Literature ed. by Kara Watts, Molly Volanth Hall, Robin Hackett

Reviewed by: Affective Materialities: Reorienting the Body in Modernist Literature ed. by Kara Watts, Molly Volanth Hall, Robin Hackett Marta Figlerowicz Affective Materialities: Reorienting the Body in Modernist Literature, ed. Kara Watts, Molly Volanth Hall, and Robin Hackett. (Gainesville: University Press of Florida, 2019). Pp. 274. $85.00 (cloth). As I read Affective Materialities: Reorienting the Body in Modernist Literature, my mind wandered to a 1929 essay by Theodor Adorno. The essay considers the late quartets of Ludwig van Beethoven and the early compositions of Franz Schubert. Adorno describes the transition between the two composers as follows: He who crosses the threshold between the years of Beethoven’s death and Schubert’s will shiver, like someone emerging into the painfully diaphanous light from a rumbling, newly formed crater frozen in motion, as he becomes aware of skeletal shadows of vegetation among lava shapes in these wide, exposed peaks, and finally catches sight of those clouds drifting near the mountain, yet so high above his head. He steps out from the chasm into the landscape of immense depth bounded by an overwhelming quiet at its horizon, absorbing the light that earlier had been seared by blazing magma.1 A reader of modernist criticism will be instantly familiar with the grand style and chilly backdrop Adorno adopts here. Four years earlier, in his introduction to The New Science (1925), Erich Auerbach imagined a Giambattista Vico who “stands alone in the icy air of a glacier, and above him stretches the immense baroque horizon of the vault of heaven.”2 Ten years earlier still, in The Theory of the Novel (1915), Georg Lukács described how an antiquity “guided by the stars” was superseded by a modern “world abandoned by God,” to whose prayers and hopes the starry sky had cooled.3 Inspiring or perhaps enabling each other, modernism’s literary-critical greats had an infinity of such cold abysses at the ready, holding them out before artists and writers to echo their solitude, futility, and belatedness, but also the enormous latent force of their feelings. Such passages spring to mind when reading Affective Materialities for two reasons. First, they illustrate a thesis that forms the volume’s [End Page 185] through line. For all of modernism’s suspicion of sentiment and emotion, the authors argue, their writings brim with affects understood as more impersonal psychic and bodily forces. But modernists find affects in unexpected, counterintuitive contexts in which one would not have expected them to emerge or linger. Barren like crystals, ruins, corpses, and moonscapes, these contexts testify to affect’s survival beyond, and independence of, the fixtures of subjectivity. Present-day lovers of such counterintuitive affective sites will be pleased by this volume’s themes and approaches. From Molly Volanth Hall and Kara Watts’s introductory essay on ether, through Karen Guendel’s reflections on flesh and granite and William Kupinse’s on “cold crystal,” the essays weave together some of the most radically anti-humanist strands of affect theory and new materialism. They also show that these late twentieth-century theoretical standpoints describe modernist aesthetic attitudes very well. Each chapter focuses on one or two major writers: T. S. Eliot, William Carlos Williams, Djuna Barnes, H.D., and others. Most are Anglophone, the rare exception being Kathryn Van Wert’s discussion of Rainer Maria Rilke. Monophone as it is, the volume does not feel provincial. Its philosophical and political aims are broad and the range of topics on which it touches—from ecology to queer theory—is considerable. In the concluding essay, Robin Hackett movingly brings the volume’s concerns into the present moment. She applies its methods to the racism and queerphobia that subtend the architectural and affective politics of gender segregation in twenty-first century America—and powerfully condemns the ways in which emotions, as opposed to affects, bolster these harmful social patterns. “[E]motion produces the others of racist seclusion” in the “circumstances” Hackett describes; “[b]lank affect, alternately, produces access” to shared social spaces by challenging and partly neutralizing the normative categories that emotions reinforce (249–250). The second tie that links Adorno’s, Auerbach’s, and Lukács’s icy landscapes to Affective Materialities is...

Solvent flows, conformation changes and lattice reordering in a cold protein crystal.

When protein crystals are abruptly cooled, the unit-cell, protein and solvent-cavity volumes all contract, but the volume of bulk-like internal solvent may expand. Outflow of this solvent from the unit cell and its accumulation in defective interior crystal regions has been suggested as one cause of the large increase in crystal mosaicity on cooling. It is shown that when apoferritin crystals are abruptly cooled to temperatures between 220 and 260 K, the unit cell contracts, solvent is pushed out and the mosaicity grows. On temperature-dependent timescales of 10 to 200 s, the unit-cell and solvent-cavity volume then expand, solvent flows back in, and the mosaicity and B factor both drop. Expansion and reordering at fixed low temperature are associated with small-amplitude but large-scale changes in the conformation and packing of apoferritin. These results demonstrate that increases in mosaicity on cooling arise due to solvent flows out of or into the unit cell and to incomplete, arrested relaxation of protein conformation. They indicate a critical role for time in variable-temperature crystallographic studies, and the feasibility of probing interactions and cooperative conformational changes that underlie cold denaturation in the presence of liquid solvent at temperatures down to ∼200 K.

A phase diagram-based toolbox to assess the impact of freeze/thaw ramps on the phase behavior of proteins.

The influence of process parameters during freeze/thaw (FT) operations is essential for the preservation of the protein stability/activity during production and storage processes in the biopharmaceutical industry. Process parameters, such as FT ramps, the final storage time and temperature, affect the occurring FT stress onto the target protein in different ways. FT stress includes cold denaturation, freeze concentration, and ice crystal formation which can result in protein aggregation. To visualize the impact of variations in FT ramps, descriptors such as solubility, phase behavior and crystal morphology were evaluated. The phase diagram-based toolbox in combination with an HTS-compatible cryo-device allowed the identification of suitable ramping schemes during FT operations. It could be clearly shown that rapid operations are needed above the glass transition temperature of the target protein to circumvent precipitation during FT cycles. Finally, a stability index is introduced which allows ranking of thesystems investigated.

Ion Coulomb crystal in a polychromatic optical superlattice

We demonstrate that the earlier suggested new all-optical method of creating long-term small (containing two or three particles) ion clusters using the rectified optical forces (RFs) can be used to create cold trapped Coulomb crystals (consisting of several tens of resonant ions). The results of the supercomputer simulations of the dynamics of a mercury ion cloud in a polychromatic optical superlattice (induced by RFs) are presented and analysed. Such a cloud (including 49 ions) in the absence of the optical field expands rapidly (during the characteristic time of the order of ) as a result of the Coulomb explosion. It is shown that the polychromatic optical field can result in the ‘quenching’ of the Coulomb explosion and crystallisation of the ion cloud: creation of a quasi-2D array of ordered and strongly coupled cold ions (with the Coulomb coupling parameter and temperature ∼10−3 K). The mean destruction time of the studied metastable crystal is of the order of 10 s. Moreover, the central core of the ion cloud can retain its crystalline configuration for a much longer time.

These Are Good Indians

These Are Good Indians Richard Osborn Hood (bio) Somewhere in the lush hot fields of August are born the first snows of October, November at the latest. Soft cold crystals falling, piling on to the unfinished works of man, bringing calamity. If a house has an incomplete roof, openings in the walls, openings in the sheathing, snow drifts in, settles, gets heavy and wet. Then mold, warp, expansion, seepage, freeze and thaw, freeze and thaw, the forces that split boulders. In no time, a floor pops up, walls twist, pipes leak, ice penetrates a joint, part of a roof shears off. Nature reclaims the materials. In these mountains, a house begun but not closed in, exposed to one winter, becomes a ruin. And in the spring, you may as well just tear it down and start over, if you've still got the money and the will. Most of them don't. They sell at a loss and go elsewhere. There was one such ruin, a hulk, abandoned but still standing, off a road near our site up in the Village. It was said that the owner of the hulk was in a southern desert, not responding to inquiries. ________ "No," I said to the phone, "No wedding." "No wedding," I repeated, for emphasis, and punched off the call. "The point is, no wedding party," I explained to my foreman. "What's the problem?" he asked. "Where those guys are from, they have a saying that at a wedding party, if nobody died, if nobody got killed, it probably wasn't a good party." ________ Our owner's name was Mark. I discouraged referring to him as The Mark. Mark was standing in the driveway beside a delivery of logs and windows, and with Mark was the building inspector. It was the inspector's first visit, his introduction. Mark took charge, all dense and restrained, like he'd been called upon to show a cathedral to a shepherd. He told the inspector I was the general contractor, and led us all to the drawings, such as they were. Then he extended a hand toward the house. "The builders are Navajo," Mark explained. "Navajo." He turned to face the structure taking shape. "Master builders. Deep in sacred traditions, believe me. They design as they go. They place each log in harmony with the elements—wind, fire, water, earth. It has been a privilege to see them work. They are giving [End Page 150] the house a soul. Native spirit, the spirit of this place. The four directions—north, south, east, west. The essence of this property …" And so forth, and there were the four directions, for anybody who needed to know. My foreman left us, went out back to foreman some things. They laughed back there. I wished I could have a laugh break. I tuned in abruptly again when I heard Mark say to the inspector, "and we hope you won't be narrow-minded in your interpretations of the codes and regulations. For this house, you have to be flexible. We've got something special here, something unique. "Now look, I'm the kind of person that is very sensitive to my environment. I could not live in a standard house, the same as every other house. It's mindless conformity, quite frankly, herd mentality, and I just could not tolerate it. "This house is going to be different. There's going to be a lot of interest, it's going to attract some attention. I think we're going to see that it will be published. I have publishers who are interested, they're calling me every day. One called me just yesterday." The building inspector was listening carefully and his eyes were opening up very wide. Mark continued talking: "And I don't want a rigid, bureaucratic attitude on your part to drag the project down. You have to work with us, be a team player. Then we're going to get a result we can all feel good about. Don't you think?" To his big eyes, the inspector added a big smile, like the smile of the killer when he knows who he...

Proteomic identification of cryostress in epididymal spermatozoa.

BackgroundCryopreservation of epididymal spermatozoa is important in cases in which it is not possible to collect semen using normal methods, as the sudden death of an animal or a catastrophic injury. However, the freezing and thawing processes cause stress to spermatozoa, including cold shock, osmotic damage, and ice crystal formation, thereby reducing sperm quality. We assessed the motility (%), motion kinematics, capacitation status, and viability of spermatozoa using computer-assisted sperm analysis and Hoechst 33258/chlortetracycline fluorescence staining. Moreover, we identified proteins associated with cryostress using a proteomic approach and performed western blotting to validate two-dimensional electrophoresis (2-DE) results using two commercial antibodies.ResultsCryopreservation reduced viability (%), motility (%), straight-line velocity (VSL), average path velocity (VAP), amplitude of lateral head displacement (ALH), and capacitated spermatozoa, whereas straightness (STR) and the acrosome reaction increased after cryopreservation (P < 0.05). Nine proteins were differentially expressed (two proteins decreased and seven increased) (>3 fold, P < 0.05) before and after cryopreservation. The proteins differentially expressed following cryopreservation are putatively related to several signaling pathways, including the ephrinR-actin pathway, the ROS metabolism pathway, actin cytoskeleton assembly, actin cytoskeleton regulation, and the guanylate cyclase pathway.ConclusionThe results of the current study provide information on epididymal sperm proteome dynamics and possible protein markers of cryo-stress during cryopreservation. This information will further the basic understanding of cryopreservation and aid future studies aiming to identify the mechanism of cryostress responses.

Addition of Cryoprotectant Significantly Alters the Epididymal Sperm Proteome.

Although cryopreservation has been developed and optimized over the past decades, it causes various stresses, including cold shock, osmotic stress, and ice crystal formation, thereby reducing fertility. During cryopreservation, addition of cryoprotective agent (CPA) is crucial for protecting spermatozoa from freezing damage. However, the intrinsic toxicity and osmotic stress induced by CPA cause damage to spermatozoa. To identify the effects of CPA addition during cryopreservation, we assessed the motility (%), motion kinematics, capacitation status, and viability of epididymal spermatozoa using computer-assisted sperm analysis and Hoechst 33258/chlortetracycline fluorescence staining. Moreover, the effects of CPA addition were also demonstrated at the proteome level using two-dimensional electrophoresis. Our results demonstrated that CPA addition significantly reduced sperm motility (%), curvilinear velocity, viability (%), and non-capacitated spermatozoa, whereas straightness and acrosome-reacted spermatozoa increased significantly (p < 0.05). Ten proteins were differentially expressed (two decreased and eight increased) (>3 fold, p < 0.05) after CPA, whereas NADH dehydrogenase flavoprotein 2, f-actin-capping protein subunit beta, superoxide dismutase 2, and outer dense fiber protein 2 were associated with several important signaling pathways (p < 0.05). The present study provides a mechanistic basis for specific cryostresses and potential markers of CPA-induced stress. Therefore, these might provide information about the development of safe biomaterials for cryopreservation and basic ground for sperm cryopreservation.

The active site of hen egg-white lysozyme: flexibility and chemical bonding

Chemical bonding at the active site of hen egg-white lysozyme (HEWL) is analyzed on the basis of Bader's quantum theory of atoms in molecules [QTAIM; Bader (1994), Atoms in Molecules: A Quantum Theory. Oxford University Press] applied to electron-density maps derived from a multipole model. The observation is made that the atomic displacement parameters (ADPs) of HEWL at a temperature of 100 K are larger than ADPs in crystals of small biological molecules at 298 K. This feature shows that the ADPs in the cold crystals of HEWL reflect frozen-in disorder rather than thermal vibrations of the atoms. Directly generalizing the results of multipole studies on small-molecule crystals, the important consequence for electron-density analysis of protein crystals is that multipole parameters cannot be independently varied in a meaningful way in structure refinements. Instead, a multipole model for HEWL has been developed by refinement of atomic coordinates and ADPs against the X-ray diffraction data of Wang and coworkers [Wang et al. (2007), Acta Cryst. D63, 1254-1268], while multipole parameters were fixed to the values for transferable multipole parameters from the ELMAM2 database [Domagala et al. (2012), Acta Cryst. A68, 337-351] . Static and dynamic electron densities based on this multipole model are presented. Analysis of their topological properties according to the QTAIM shows that the covalent bonds possess similar properties to the covalent bonds of small molecules. Hydrogen bonds of intermediate strength are identified for the Glu35 and Asp52 residues, which are considered to be essential parts of the active site of HEWL. Furthermore, a series of weak C-H...O hydrogen bonds are identified by means of the existence of bond critical points (BCPs) in the multipole electron density. It is proposed that these weak interactions might be important for defining the tertiary structure and activity of HEWL. The deprotonated state of Glu35 prevents a distinction between the Phillips and Koshland mechanisms.

Comparison of melting and crystallization behaviors of polylactide under high-pressure CO2, N2, and He

This study investigated the melting and crystallization behaviors of polylactide (PLA) under high-pressure CO2, N2, and helium (He) using a high-pressure differential scanning calorimeter and a wide-angle X-ray diffractometer. The results showed that the PLA's melting temperature was depressed only when contacted with pressurized CO2 where at high CO2 pressures the lubricating gas molecules induced more imperfect melt and cold crystals during the cooling and heating cycle. PLA's melt crystallization was analyzed during both isothermal and nonisothermal processes. In contrast to the effect of dissolved CO2 that expedited the PLA's crystallization rate, N2 showed almost a neutral impact on the PLA's crystallization kinetics. Because of the lower solubility, N2 gas dissolved in the PLA had a diminutive plasticization effect, and thereby it could only counterbalance its negative hydraulic pressure effect. Moreover, as the helium pressure increased, the PLA's final crystallinity was reduced due to the dominant effect of helium's hydraulic pressure.

Quantum magnetism of spin-ladder compounds with trapped-ion crystals

The quest for experimental platforms that allow for the exploration, and even control, of the interplay of low dimensionality and frustration is a fundamental challenge in several fields of quantum many-body physics, such as quantum magnetism. Here, we propose the use of cold crystals of trapped ions to study a variety of frustrated quantum spin ladders. By optimizing the trap geometry, we show how to tailor the low dimensionality of the models by changing the number of legs of the ladders. Combined with a method for selectively hiding ions provided by laser addressing, it becomes possible to synthesize stripes of both triangular and Kagome lattices. Besides, the degree of frustration of the phonon-mediated spin interactions can be controlled by shaping the trap frequencies. We support our theoretical considerations by initial experiments with planar ion crystals, where a high and tunable anisotropy of the radial trap frequencies is demonstrated. We take into account an extensive list of possible error sources under typical experimental conditions, and describe explicit regimes that guarantee the validity of our scheme.

Reoperative valve surgery after open-heart valve surgery: a report of 155 cases

To summarize the characteristics of reoperative valve surgery after previous open-heart valve surgery. From 1996 to 2010, 155 patients who underwent reoperative valve surgery, either valve replacement or tricuspid annuloplasty or the repair of perivalvular leakage were included in the study. The reoperative interval was 1-266 (94.82 ± 85.37) months. All surgeries were carried out with extracorporeal circulation under moderated hypothermia. The cardioplegic solution in cold crystal or blood was used if heart beating was stopped during the surgery. The total in-hospital mortality was 5.81%, while it was 2.75% from 2005 to 2010. The end-diastolic dimension, size of atrium and ventricles were reduced after the reoperation. Ventricular arrhythmia and low cardiac output were the most frequent complications. The success rate of reoperative valve surgery can be improved by the distinctive therapeutic strategies based on the clinical characteristics and therapy principles obtained from practice experiences.

Effects of Wood Fiber Content on Structure and Properties of WF/PLA Bio-Composites

This study is devoted to investigate the effects of wood fiber content on structure and properties of wood fiber /poly(lactic acid) bio-composites (WF/PLA bio-composites). The WF/PLA bio-composites with WF from 30% to 60% and from 70% to 90% were prepared using melt extrusion and high-speed mixing methods respectively. The physical, mechanical, thermal, and macromolecular properties of WF/PLA bio-composites were evaluated. The results are as follows: Density of WF/PLA bio-composites increased when WF increased from 30% to 60%, and decreased when WF increased from 70% to 90%. Water resistance of bio-composite decreased with increasing WF content. The flexural strength of WF/PLA bio-composites were lowered when adding WF into PLA. The flexural strength decreased when WF increased from 30% to 50%, and then increased when WF increased from 60% to 80%. The flexural modulus of the bio-composite was higher than that of PLA without WF. Both n and w of PLA in WF/PLA bio-composite were decreased more than 70% with WF increased. The Tg, Tm values of PLA in the bio-composites were decreased with the WF increased. The cold crystal temperature (Tcc) was decreased with WF increased at low WF content. All the property changes were related to the decreasing of molecular weight of PLA in WF/PLA bio-composites.

Observation of ion Coulomb crystals in a cryogenic linear octupole rf ion trap

Ion Coulomb crystals of laser-cooled ${\text{Ca}}^{+}$ ions have been observed in a cryogenic linear octupole rf ion trap for the first time. Due to the almost field-free central region, large ion crystals containing over ${10}^{4}$ ions of millimeter size were successfully produced. The shapes of the crystals can be manipulated by changing the static voltages applied to the octupole rods and the endcap electrodes. Quasi-two-dimensional Coulomb crystals consisting of a small number of ions were also observed with single-ion sensitivity. When a large number of ions is crystallized in the octupole trap, a new kind crystal image with a dip along the axial direction was obtained. The results show that a linear octupole trap and multipole traps are available for producing large, cold, and novel ion Coulomb crystals. The planar ring-type crystal which has not been observed before may lead to future interesting applications.

Episodic formation of cometary material in the outburst of a young Sun-like star

The Solar System originated in a cloud of interstellar gas and dust. The dust is in the form of amorphous silicate particles and carbonaceous dust. The composition of cometary material, however, shows that a significant fraction of the amorphous silicate dust was transformed into crystalline form during the early evolution of the protosolar nebula. How and when this transformation happened has been a question of debate, with the main options being heating by the young Sun and shock heating. Here we report mid-infrared features in the outburst spectrum of the young Sun-like star EX Lupi that were not present in quiescence. We attribute them to crystalline forsterite. We conclude that the crystals were produced through thermal annealing in the surface layer of the inner disk by heat from the outburst, a process that has hitherto not been considered. The observed lack of cold crystals excludes shock heating at larger radii.

Sulfur Dioxide and Water: Structures and Energies of the Hydrated Species SO2·nH2O, [HSO3]–·nH2O, [SO3H]–·nH2O, and H2SO3·nH2O (n = 0–8)

AbstractThe structures of a large number of hydrates of sulfur dioxide (SO2·nH2O), of the sulfonate ion ([HSO3]–·nH2O), of the tautomeric hydrogensulfite anion ([SO3H]–·nH2O), and of sulfurous acid (H2SO3·nH2O) with up to eight water molecules attached to these species have been optimized at the B3LYP/6‐31G(2df,p) level of theory (DFT). The calculated vibrational frequencies allow the definite assignment of certain characteristic modes, and in this way a convincing interpretation of published spectra of aqueous SO2 as well as of SO2 adsorbed on very cold ice crystals has been achieved for the first time. Single‐point calculations at the G3X(MP2) level of theory were used to calculate the binding energies of the water molecules in SO2·nH2O as well as the relative stabilities of the isomeric anionic species [HSO3]–·nH2O and [SO3H]–·nH2O. Generally, the water molecules tend to stick together forming clusters, whereas the particular sulfur‐containing molecule remains at the surface of the water cluster, but it is always strongly hydrogen‐bonded. Only when there are more than six water molecules are the anions more or less completely surrounded by water molecules. DFT calculations erroneously predict that the gaseous hydrated sulfonate ions are more stable than the isomeric hydrogensulfite ions, even when hydrated with six water molecules. However, if these hydrated species are calculated as being embedded in a polar continuum simulating the aqueous phase, the hydrogensulfite ions are more stable than the sulfonate ions, in agreement with various spectroscopic observations on aqueous sulfite solutions. On the other hand, at the higher G3X(MP2) level, the gaseous hydrated hydrogensulfite anions are more stable than the corresponding sulfonate ions only if the number of water molecules is larger than four, whereas for the weakly hydrated anions the order of relative energies is reversed. The possible implications of these results for the enzymatic oxidation of “sulfite ions” ([HSO3]– and [SO3H]–) by sulfite oxidase are discussed. The conversion of SO2·6H2O into its isomer H2SO3·5H2O is predicted to be exothermic (ΔH°298 = –56.1 kJ mol–1) and exergonic (ΔG°298 = –22.5 kJ mol–1). (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2009)