Amorphous Crystallization Research Articles

Two-dimensional electron gas in a metal/amorphous oxide interface with spin-orbit interaction

The formation of novel two-dimensional electron gas (2DEG) with high mobility in metal/amorphous interfaces has motivated an ongoing debate regarding the formation and novel characteristics of these 2DEGs. Here we report an optical study, based on infrared spectroscopic ellipsometry, of nonmagnetic metal and amorphous semiconducting oxide (Cu/Bi$_2$O$_3$) interfaces that confirms the formation of a 2DEG with spin orbit coupling (SOC). The 2DEG optical response was simulated with a uniaxial diagonal dielectric tensor within a sub-nanometer thin layer, where its $x$ and $z$ components lineshapes resolved in both free-electron and peak-like contributions, resulted very similar to theoretical predictions [M. Xie et al., Phys. Rev. B $\bf{89}$, 245417 (2014)] of a two dimensional electron gas confined in the normal direction of a perovskite interface. In particular, the small but finite conducting character of the $z$ component provides a unambiguous signature of the presence of the 2DEG in the Cu/Bi$_2$O$_3$ system. Although the original constituent materials do not possess spin-orbit coupling (SOC), the resulting interfacial hybridization of such states induce electronic asymmetric wave functions. This work demonstrates the detection of 2DEG in amorphous crystals allowing to study its challenging interfacial phenomena such as SOC and interface-bulk coupling, overcoming an experimental impediment which has hold back for decades important advancements for the understanding of 2DEGs in amorphous materials.

Investigation on Antimalarial Activity of Rhizome of Zingiber cassumunar Roxb. (Meik-tha-lin-oot)

This research aims to investigate the antimalarial activity of rhizome of Zingiber cassumunar Roxb. (Meik-tha-lin-oot). The preliminary phytochemical investigation revealed the presence of a-amino acids, carbohydrates, glycosides, organic acids, phenolic compounds, reducing sugars, saponins, starch and terpenoids. The various crude extracts such as PE (7.11%), 95% EtOH (3.44%), EtOAc (1.64%) and H2O (1.44%) extracts were prepared by successive solvent extraction method. Curcumin (orange amorphous crystal, 0.00317% yield, M.pt=183ºC) was isolated from EtOAc crude extract by using thin layer and column hromatographic separation techniques and identified by comparing with UV and FTIR spectral data of the standard curcumin. In vitro antimalarial activities of curcumin, ethanol and watery extracts were screened by using the reported method. The ethanol and watery extracts had no antimalarial activity (EC50 values=398.07 µg/ml and 501.00 µg/ml) whereas the isolated compound, curcumin was found to inhibit the growth of Plasmodium falciparum (EC50=101.74 µg/ml). On the other hand, the isolated compound, curcumin exhibited the moderate antimalarial activity and may be used as a potential compound to be tested for newer antimalarial agent.

Anisotropic Epitaxial Behavior in the Amorphous Phase-Mediated Hydroxyapatite Crystallization Process: A New Understanding of Orientation Control.

The precise control of crystallization is a key in the construction and engineering of crystalline materials, especially in biomineralization. Although it is generally accepted that biomineral crystals have evolved from their amorphous precursors, there are intense debates about crystallographic orientation control. By using in situ high-resolution transmission electron microscopy, we herein reveal that hydroxyapatite (HAP) is produced through its epitaxial growth from amorphous calcium phosphate with a preferential c-axis orientation. Abnormally but interestingly, this anisotropic epitaxial crystallization priority along the c-axis is not affected by the existing HAP crystalline substrate, which is exactly the same on either {002} or {100} facets. Molecular dynamics simulations suggest this preference is correlated with the interfacial energetic controls at the amorphous-crystalline transition frontier. The orientation control of biominerals here shows the key role of the interface energy, rather that the organic molecules or matrices, which provides a complementary understanding of the general c-axis orientation control of HAP in various biomineralization cases and aids in the development of an alternative strategy for crystallization control of functional materials.

Numerical and experimental investigation of the stability of a drop in a single-axis acoustic levitator

Acoustic levitation can be employed to hold liquid drops in midair, enabling novel applications in X-ray scattering of proteins, amorphous crystallization of solutions, or contactless mixing. Multiple studies have characterized the physical behavior of a levitated drop inside an acoustic field. Here, we present a numerical and experimental study on the acoustic levitation of water drops in a single-axis acoustic levitator consisting of an ultrasonic transducer and an opposing reflector. Instead of modeling an abstract incident acoustic field, our model considers the shape of the drop as well as the real geometry of the levitator. We also use a high-speed camera to observe the disintegration and the undesired oscillations of the drops. Our results show that the insertion of a drop in the levitator provokes a shift in its resonant frequency that depends on the shape of the drop. Second, the levitation behavior depends on whether the levitator operates slightly below or above the resonance. Third, if the levitator is driven above the resonant frequency, it is possible to levitate with more strength and avoid disintegration of the drop. This research provides an insight on how to achieve more stable experiments that avoid the bursting and undesired oscillations of the levitated sample. We hope that it will facilitate numerous experiments involving acoustically levitated liquid drops.

Amorphous Photonic Structures with Brilliant and Noniridescent Colors via Polymer-Assisted Colloidal Assembly.

Efficient and large area fabrication of amorphous photonic crystals (APCs) with multicolor, angle independency, and fine resolution is always desired owing to their application in color displays, sensors, and pigments. Here, we report a polymer-assisted colloidal assembly (PACA) method to fabricate APCs with brilliant structural colors by the co-assembly of silica colloidal particles, polyvinylpyrrolidone (PVP), and carbon black (CB). PVP is the key to enable the amorphous aggregations of the particles, the uniform and noniridescent structural colors of the APCs. Moreover, multicolor and high-resolution patterns can be prepared through the mask-based brush printing with colloids–PVP–CB precursor solution as ink (named as APCs-ink). The developed printing method can be applied to various substrates with different roughness, curvature, and flexibility such as papers, metals, plastic films, stones, and even curved glasses. PACA is efficient and straightforward for the fabrication of APCs and high-resolution patterns with large area, low cost, and easy operation, which will facilitate their practical applications in the fields of color-related display, green painting, anticounterfeiting, and so on.

213 Variables Associated With Gonorrhea And Chlamydia in the Emergency Department

Gonorrhea (NG) and chlamydia (CT) are frequently diagnosed sexually transmitted infections (STIs) in the emergency department (ED). Results of nucleic acid amplification tests (NAATs) are not available at the time of the clinical encounter requiring providers to decide whether to treat the patient in the ED or wait for the NAAT results to come back. Not treating the patient in the ED risks the ED not being able to reconnect with the patient for treatment if the NAAT is positive. Clinical gestalt about who has a STI is poor leading clinicians to significantly over-treat patients for STIs when none exists as well as miss those with the disease. The objectives of our study were to determine the variables associated with NG and CT infection in the ED. We reviewed 17,358 female and 1,119 male encounters where testing was performed for NG and/or CT in EDs in northeast Ohio between 2012 and 2017. We performed Chi-square analysis or t-tests using data obtained at triage including demographic information, mechanism of ED arrival, ED disposition, ED length of stay, pain level, ICD-9 and ICD-10 codes, and the vaginal wet prep, STI testing, urinalysis, and urine culture results to identify the independent variables associated with having NG and/or CT. An alpha 0.05 was sent for statistical significance. In our cohort 9.8% (1703) of females and 6.9% (759) of males were positive for NG and/or CT by NAAT. The following variables were significantly associated being infected for NG and/or CT in females: younger age, black race, unmarried, Medicaid insurance, higher emergency severity index (ESI), no primary care physician, pregnant, infected with Trichomonas vaginalis, lack of yeast but the presence of clue cells on vaginal wet prep. Additionally, on urinalysis there were positive associations between leukocyte esterase, white blood cell (WBCs), WBC clumps, nitrite, protein, urine red blood cells (RBCs), amorphous crystals, and not having glucose in the urine. For men the following variables were significantly associated with being infected with NG and/or CT: younger age, black race, unmarried, higher ESI, WBC on penile wet prep, and on urinalysis: higher WBCs, positive leukocyte esterase, WBC clumps, mucus, proteinuria, urine bacteria, urine RBCs, urobilinogen, and lack of glucose. Univariate analysis shows multiple independent variables significantly associated with both NG and/or CT infection in males and females in the ED. Clinicians’ decisions regarding treatment for STIs in the ED inherently rely on a form of Bayesian analysis because definitive test results are not available at the time of the clinical encounter. No validated clinical decision rules regarding treatment of STI in the ED have yet been developed. The independent variables identified in our analysis can be utilized for future multivariate analysis to help create clinical decision tools to aid clinicians caring for persons being evaluated for STIs.

Clinical and genetic analysis of idiopathic normophosphatemic tumoral calcinosis in 19 patients.

Tumoral calcinosis is a rare clinicopathological entity characterized by ectopic soft-tissue calcification, typically periarticular. Normophosphatemic tumoral calcinosis is seldom reported in East Asian populations, and the preoperative diagnosis is often elusive. This study was performed to characterize the clinical profile of normophosphatemic tumoral calcinosis and investigate the presence of the SAMD9 gene mutation. The clinical features, pathological examination findings, and outcomes of 19 subjects were retrospectively reviewed. All patients were analyzed for SAMD9 gene mutation using paraffin-embedded tumoral calcinosis specimens. Nineteen subjects were analyzed (7 males, 12 females). Their mean age at surgery, mean age at symptom onset, and median disease duration was 51.9 ± 17.3 (range 7-75)years, 49.1 ± 17.2 (range 7-74)years, and 1.3 (interquartile range 0.5-3.0)years, respectively. Lesions were located in the hand in 8 (42.1%) subjects; wrist in 5 (26.3%); shoulder in 2 (10.5%); and hip, knee, buttock, and scrotum in 1 (5.3%) subject each. The lesions in 17 (89.5%) subjects were located around the joints [small joints (hand and wrist) in 13 (68.4%) and large joints (shoulder, hip, and knee) in 4 (21.1%)]. Lesions occurred in the upper limbs in 15 (78.9%) subjects and in the lower limbs in 2 (10.5%). Multiple-lesion involvement (distal right index finger and middle finger) occurred in one (5.3%) subject. Symptoms included pain in 15 (78.9%) subjects, impaired mobility in 5 (26.3%), swelling in 5 (26.3%), numbness in 2 (10.5%), and an asymptomatic mass in 2 (10.5%). The serum inorganic phosphorus concentration was normal in all 19 subjects (mean 1.17 ± 0.15mmol/L). The serum calcium concentration was normal in 18 subjects and low in 1. The serum alkaline phosphatase concentration was normal in all 19 subjects. Pathological examination indicated multiple nodules of calcified materials that manifested an amorphous or granular blue-purple crystal and were surrounded by proliferation of mononuclear or multinuclear macrophages, osteoclastic-like giant cells, fibroblasts, and chronic inflammatory cells. Notably, different phases of pathological manifestations were observed in the same microscopic field. During follow-up (0.5-65.0months), no recurrence of tumoral calcinosis was observed in 18 (94.7%) subjects, but 1 subject developed in situ recurrence of an asymptomatic subcutaneous mass after 6months postoperatively. Genetic analysis in all 19 subjects revealed no SAMD9 gene mutations. Most subjects were females and developed calcinosis in adulthood. Small joints (hand and wrist) and the upper limbs were frequently involved. The presence of different phases of pathological features in the same subject suggests that about half of the study participants had been misdiagnosed with another condition (such as gout, osteoarthritis, etc.). Complete surgical excision led to cure without recurrence during follow-up in majority of the study participants.

Tough, Freestanding, and Colorless Photonic Paper Using Water as Ink

AbstractStructural colors arising from interactions of light with submicron scale periodic structures have been found in nature. Inspired by photonic materials, rewritable paper using water as ink is fabricated via entrapping amorphous colloids crystals film into hydrogel. This photonic paper is tough, free‐standing, transparent, and colorless in dry state, just like plastic sheet. Marks display using water as ink to write on the paper and disappear with the evaporation of water. The color of the marks similar to that of the initial PS colloids film and could be tuned by changing the size of the colloids. The photonic paper possesses high durability and can be rewritten over 70 cycles without significant color fading. Besides, the retention time of the written marks could be well controlled from minutes to weeks by using glycerol/water as ink. It is worth noting that long‐range order is not the necessary condition for the formation of photonic paper, which makes the preparation easy to achieve. More interesting, the wet hydrogel film is sensitive to strain, and has the potential to be mechanical sensor.

Electromagnetic field in human sperm cryopreservation improves fertilizing potential of thawed sperm through physicochemical modification of water molecules in freezing medium.

Physicochemical properties of water molecules as the main compositions of the freezing media can be affected by the electromagnetic fled. The purpose of this study was to apply extremely low repetition rate electromagnetic fields (ELEFs) to change the molecular network of water molecules existing in freezing media used for human sperm cryopreservation. First, different time periods and pulsed electromagnetic fields were used to evaluate the physiochemical properties of water. The lowest rate of cluster size, surface tension, viscosity, and density was observed for water samples exposed to 1000 Hz ELEF for 60 min (P < 0.05) that could be results in small ice crystal formation. Therefore, this treatment was selected for further evaluations in human sperm freezing because there was minimal probability of amorphous ice crystallization in this group. To assess fertilizing potential, human semen samples were subjected to ELEF (1000 Hz) water-made freezing medium and cryopreserved. The highest percentage of total motility, progressive motility, viability, membrane integrity, mitochondrial membrane potential, DNA integrity, and TAC were obtained in frozen ELEF as compared to other groups. The percentage of viable spermatozoa (Annexin V-/PI-) in frozen ELEF was significantly higher than in frozen control. The level of ROS was significantly lower in frozen ELEF when compared to frozen control. It can be concluded that the modification of physicochemical properties of water existing in cryopreservation media by ELEF is a suitable strategy to improve the outcome of cryopreservation.

Prevalence and chemical composition of uroliths in fattening pigs in Belgium

The present study investigated the prevalence of uroliths in fattening pigs and assessed the composition of these urinary tract concrements. In total, 2,432 urinary bladders were sampled in the slaughterhouse and checked for abnormal content. Urinary samples were analysed microscopically, and samples of the urinary bladder wall were tested for histological signs of inflammation. The composition of the concrements was examined by infrared spectrophotometry. Macroscopic and microscopic abnormalities were detected in 8.4% and 52.8% of the samples respectively. Magnesium ammonium phosphate (struvite), calcium oxalate dihydrate (COD), calcium carbonate (calcite), calcium oxalate monohydrate (COM) and amorphous crystals were detected. Analysis of stones showed COD in all samples in different proportions. The calcium content of examined stones was always considerable (up to 34%), in contrast to the magnesium content which represented max 1.9%. Struvite was found in one third of the samples, but was never part of stones and grit. COD crystals were the second most common microscopic crystal. These COD crystals and some COD stones had a rectangular shape, and therefore, they can be harmful to the bladder mucosa. In conclusion, uroliths are present in a large proportion of male fattening pigs, and consequently, urinary concrements pose a life-threatening risk for urethra obstruction in male pigs. Further research is warranted to identify potential risk factors for urolithiasis and microscopic crystals.

Preparation of Noniridescent Structurally Colored PS@TiO2 and Air@C@TiO2 Core-Shell Nanoparticles with Enhanced Color Stability.

Natural amorphous photonic crystals benefit from reflectance at selective wavelengths in some specific existing natural systems. Noniridescence from natural organisms has also attracted great interest for various examples in bionic colors, pigments, and paintings. Here, Air@C@TiO2 sphere was obtained by the first calcination of PS@TiO2 core-shell nanoparticles in nitrogen to ensure the integrity of the shell structure followed by low-temperature calcination to obtain the appropriate color saturation. We demonstrate that, compared with the prepared colored PS@TiO2/carbon black (CB) pigments, angle-independent hollow Air@C@TiO2 nanoparticles have enhanced color stability under the action of in situ synthesized carbon black (CB). Our results suggest that it is easy to change the color of these Air@C@TiO2 spheres by adjusting the sphere structure sizes, which have the potential to show visual signaling.

Few-cycle solitons in a quasiequilibrium nanodispersed medium of asymmetric molecules

The nonlinear dynamics of extremely short electromagnetic pulses in a nanodispersed birefringent medium is investigated. The matrix of the medium and chaotically mixed nanogranules form an amorphous photon crystal containing asymmetric molecules of identical chemical composition. The concentrations of molecules in the nanogranules and in the matrix are different. This nanodispersed (discrete) structure of the medium leads to spatial dispersion. The wave equation for the ordinary component of pulses propagating in such a medium is derived under the conditions of the sudden perturbation approximation. This equation generalizes the sine-Gordon and Rabelo–Fokas equations and appears to be integrable in the frameworks of the inverse scattering transformation method if an additional restriction on the parameters characterizing the spatial dispersion and anisotropy of the medium is imposed. This restriction implies that the medium is prepared in the quasiequilibrium state before the pulse effect, when the molecules in the matrix or the ones in the nanogranules are in the excited state. The soliton and breather solutions of the integrable wave equation are investigated.

Exploring the Link Between Amorphous Structure and Crystallization Behavior of Titania Thin Films by Electron-Based Pair Distribution Functions and in-situ TEM

Exploring the Link Between Amorphous Structure and Crystallization Behavior of Titania Thin Films by Electron-Based Pair Distribution Functions and in-situ TEM

Electrical properties of amorphous films and crystallization of Li–Nb–O system on silicon

Li–Nb–O amorphous films were deposited onto Si substrates by the radio-frequency magnetron sputtering method in an Ar environment. As-grown films are crystallized under thermal annealing (TA) at the temperature of up to 600 °C with a formation of LiNbO3. Capacitance–voltage and current–voltage analysis revealed a positive fixed oxide charge existed in the films. TA influences the structure and electrical properties of as-grown films. The fraction of a crystalline phase in the film increases from 45 to 100% when raising the annealing temperature from 450 to 475 °C. The effective positive charge in the amorphous films changes non-monotonically with TA reaching a minimum value at the temperature of 450 °C when the effective dielectric constant has a maximum value. The concentration of traps in the films depends on the annealing temperature and reaches a minimum value at T = 600 °C which is caused by the formation of the large-block crystalline structure. Charge transport mechanisms are also discussed.

Deposition of amorphous hardening coatings by electrospark treatment in a crystalline granule mixture

The article focuses on the preparation of amorphous coatings on the Steel 1035 surface by electric spark treat the coating composition control by changing the granule mixture composition was studied. EDS analysis showed that the coatings obtained contain W, Mo, Co and Ni in different ratios. The weight of granules having different compositions decreased by 11–16 wt.% in 6 hours of treatment as a result of electric erosion. The mass transfer coefficient varied from 33 to 54 %. X-ray diffraction analysis showed the predominance of the amorphous phase in the composition of layers deposited. Annealing of the coatings at 1150 °C led to amorphous phase crystallization into M23(C,B)6 type borocarbide and α-Fe. The coatings had an increased microhardness of 10–15 GPa, and their wear resistance under dry sliding wear conditions at 10 and 50 N loads was 3,3 and 1,6 times higher, respectively, than in Steel 1035. The highest values at both loads were shown by samples without nickel, while samples without tungsten featured the lowest values. The coatings had a friction coefficient within 0,27–0,31 that is lower than for Steel 1035 by 13–30 %. Wear resistance of the coatings under dry abrasive wear conditions at the 25 N load was 3 to 5 times higher as compared to uncoated Steel 1035. Samples without nickel demonstrated the best performance, while samples without cobalt had the worst indicators. Thus, it was shown that tungsten and cobalt increase wear resistance of iron-based amorphous alloys, while nickel and molybdenum tend to worsen their tribotechnical behavior.

A Review on High‐Strength Titanium Alloys: Microstructure, Strengthening, and Properties

The authors review the recent advances in the development of high‐strength titanium alloys. First, they summarize conventional strengthening approaches and their mechanisms, thecorresponding microstructures, and the optimized mechanical properties. Subsequently, various strengthening strategies for high‐strength titanium alloys are discussed. Finally, examples of the successful development of high‐strength titanium alloys based on amorphous crystallization via solid and semi‐solid sintering are presented. The review of the interrelation between the microstructure, the strengthening, and the properties may provide significant insight into achieving novel high‐strength titanium alloys.

Hand Painting of Noniridescent Structural Multicolor through the Self-Assembly of YOHCO3 Colloids and Its Application for Anti-Counterfeiting.

YOHCO3 colloidal particles with tunable size, composition, and optical properties were prepared, and they were used for the fabrication of amorphous photonic crystals? (APCs) patterns through direct hand painting. YOHCO3 colloids were synthesized by a seeding growth method, in which the colloid size could be controlled by altering the seed amounts and the composition and optical properties can be altered via the doping of Eu3+. APCs? films with bright, permanent, and tunable structural colors were prepared by the self-assembly of YOHCO3 colloids of different sizes. Multicolor patterns can be obtained quickly and efficiently by hand painting with the dispersion of YOHCO3 colloids as ink. An APCs? pattern assembled from YOHCO3:Eu colloids is also fabricated, and the pattern shows blue structural color under natural light and bright red colors under illumination of UV light. The facile synthesis procedure, simple assembly process, and unique optical properties of the APCs make it valuable for practical applications such as structural color-based printing and anticounterfeiting.

Structural whiteness of the multi-component glaze dependence on amorphous photonic crystals

A kind of enhancing mechanism of structural whiteness dependence on amorphous photonic crystal (APC) structure is introduced in this paper. In the glaze system composed of albite, kaolin, talc, calcite, quartz, titanium dioxide and zinc oxide, the APC structure will be produced by using quartz as a variable to induce the phase separation. Under different polarities between Ti, Zn etc. and Si ion, the separated spheres with the core—shell structure can be obtained and then make up opal-like APCs in the glaze layer. In addition to inner and outer layers of core—shell spheres, the calculated results of refractive indices clearly show the great difference between the particles and the matrix. As a result of different refractive indices, the multiple scatting of visible light plays a key role in the structural whiteness. However, due to the decrease of the cationic content, APCs with the reverse opal structure would be formed in the interface between glaze and body. Ultimately, the glaze appearance reveals extremely high structural whiteness due to the special APC structure.

Synthesis and self-assembly of PMMA-b-(u)PE-b-PMMA copolymers: study the aggregate morphology in toluene vapor

Well-defined poly(methyl methacrylate)-b-polyethylene-b-poly(methyl methacrylate) triblock copolymers with saturated and unsaturated PE as the central block (PMMA-b-(u)PE-b-PMMA) were synthesized by combining acyclic diene metathesis (ADMET) with thiol-ene click chemistry and atom transfer radical polymerization (ATRP). The mass ratios of (u)PE/PMMA in the copolymers are 1:1 and 1:2 respectively, while the molecular weight of the (u)PE block remained constant (22 k). The characterization, thermal properties and crystallization of copolymers were determined by 1H/13C NMR, IR, TGA, DSC and XRD. As a result, the PMMA blocks can form stereocomplex crystal, which was affected by copolymer composition as well as the crystallization of PE middle block. Under solvent vapor annealing (SVA) conditions, amorphous or weak crystallization block copolymers assembled into worm-like network aggregates, while the aggregates evolution to fibrous or banded and fabric-like network covering particles morphology driving by PE nuclear crystallization and PMMA shell crystallization respectively.

Plasticity of Persistent Photoconductance of Amorphous LaAlO3/SrTiO3 Interfaces under Varying Illumination Conditions

We report on transport measurements under optical stimulation of persistent photoconductance (PPC) at the interface between amorphous LaAlO3 films and SrTiO3 crystals. The spectral response in the ...