Maltese Cross Research Articles

Multi-scale structure, rheological and digestive properties of starch isolated from highland barley kernels subjected to different thermal treatments

Thermal treatment has been used to modify starch properties, but few studies pay attention to the change in highland barley starch (HBS) under the whole kernel treatment. The different effect of superheated steam (SS) on the HBS properties from other traditional thermal treatment is still unclear, not mention to the exactly structural change of HBS. This study explored the different effects of SS, steam and roasting treatments of HB kernel on the multi-scale structure, rheological and digestive properties of HBS. Thermal treatments led to the aggregation of HBS granules, the rough surface, and the absence of Maltese cross, as well as the increase in short-chain length ratio and amylose content. Compared with steam and roasting treatments, SS treatment increased the average molecular weight of HBS at 140 °C while reduced it at 180 °C due to starch interactions and depolymerization effect. Multi-scale structure analysis revealed that SS-180 showed the most significant disruption of HBS crystalline structure, the disorder of short-range structure, the decrease in double helix content and the disruption of lamellar structure. These structural changes of HBS resulted in the enhanced thermal stability, and decreased values of G′ and G″ representing the weaker gel structures. Meanwhile, much more resistant starch was converted from rapid digestible starch and slowly digestible starch in SS-treated HB than other thermal-treated HB. In particularly, the most change in multi-scale structure of HBS caused by SS-180 was responsible for its best thermal stability, weakest gel structures and slowest starch digestive rate.

The Isothermal and Nonisothermal Crystallization Kinetics and Morphology of Solvent-Precipitated Nylon 66.

Solvent-precipitated nylon 66 (SP PA66) is a key material used to fabricate microfiltration membranes. The crystallization kinetics and behavior of SP PA66 were investigated through differential scanning calorimetry (DSC), polarized optical microscopy (POM) and X-ray diffraction (XRD). The Avrami equation was used to describe the isothermal crystallization of SP PA66. Nonisothermal crystallization behaviors were analyzed using Avrami equations modified by Jeziorny, Ozawa and Mo. The Avrami analysis demonstrated that the k values of SP PA66 were higher than those of neat PA66. The was between 2 and 3 indicating the presence of two- and three-dimensional mode with thermal nucleation. With an increasing cooling rate, the Jeziorny crystallization rate constant increased for SP PA66; however, the Ozawa model was not satisfactory for all SP PA66 samples. The Mo method suggested that SP PA66 had a faster crystallization rate than neat PA66 during the nonisothermal crystallization process. The solvents dissolved nylon 66, rearranged it and formed a regular hydrogen-bonded region. These regions served as nucleation sites and increased the crystallization rate constant in the subsequent melting process. The crystal morphology of the SP PA66 under the POM investigation exhibited Maltese cross spherulites. The sizes of the spherulites of SP PA66 were significantly smaller than those of neat PA66. Wide-angle XRD revealed that SP PA66 had the same crystal structure and a higher crystal perfection than neat PA66.

Influence of ultrasound and microwave treatments on the structural and thermal properties of normal maize starch and potato starch: A comparative study

The effects of ultrasound and microwave on the physicochemical properties of normal maize and potato starches were compared. The cavitation effect of ultrasound loosened the internal space and destroyed the structure of starch granules, increased the damaged starch content, which was consistent with the decrease in relative crystallinity and the number and brightness of Maltese crosses, and the increase in D(0.5) and D(4,3) values. Microwave vibrated the molecules inside the granules and generated heat to destroy the structure of starch. The content of damaged starch was significantly lower in microwave-treated starch compared with ultrasound-treated starch. Microwave treatment promoted the formation of amylose–lipid complex, with the larger peak area at 20°(2θ) than that of the ultrasound-treated starch. The type of starch and the treatment sequence showed a significant effect. The results might help understand the mechanism of ultrasound and microwave treatments influencing the structural properties of starches.

Hysterosalpingography Observations in Female Genital Tuberculosis with Infertility.

Hysterosalpingography (HSG) is radiographic evaluation of uterine cavity and tubal patency. The aim of this study was to evaluate the safety and utilisation of HSG in female genital tuberculosis (FGTB) with infertility. The study was conducted in a tertiary referral centre of North India. It was a prospective study on 87 cases of FGTB with infertility. Diagnosis of FGTB was made by composite reference standard using the presence of acid-fast bacilli on microscopy/culture or positive GeneXpert, positive polymerase chain reaction or epithelioid granuloma on endometrial biopsy or definitive or probable findings on laparoscopy or hysteroscopy. Suitable statistical methods were used with STATA software version 12.0. HSG findings were normal in 49 (56.32%) cases. There were filling defects in 14 (16.09%), short and shrunken cavity in 4 (4.49%), intrauterine synechiae in 14 (16.09%), T-shaped cavity in 3 (3.44%) and deformed uterine cavity in 5 (5.74%) cases. Fallopian tube findings were hydrosalpinx in 12 (13.79%) and 11 (12.64%) cases, beading of tube in 4 (4.59%) and 2 (2.29%) cases, pipestem appearance in 2 (2.29%) cases each and Maltese cross appearance in 3 (3.44%) and 2 (2.29%) cases, respectively. Tubal blockage was seen in 69 (79.31%) and 67 (77.01%) cases being cornual block in 28 (32.18%) and 26 (29.88%) cases, mid-tubal block in 16 (18.39%) and 15 (17.24%) cases, multiple blocks in 10 (11.49%) and 12 (13.79%) cases and fimbrial block in 15 (17.24%) and 14 (16.09%) cases. None of the cases had flare-up of the disease after HSG in the current study. HSG is a useful modality in FGTB with infertility.

Polymer-directed crystallization of HMX to construct nano-/microstructured aggregates with tunable polymorph and microstructure

Multi-scale structural control of the high explosive HMX was achieved by a polymer-directed crystallization strategy. For the first time, HMX spherulites that exhibited a “Maltese cross” extinction pattern under crossed polarizers were obtained.

Dissolution of waxy maize pyrodextrin granules in mixtures of glycerol and water, separating loss of crystallinity from loss of birefringence

Pyrodextrins were prepared by heating waxy maize starch for 4 h at pH 3 & 150 °C, pH 3 & 170 °C, and pH 2 & 150 °C. Those pyrodextrins were soluble in water at 25 °C, but insoluble in glycerol. The objectives of this study were to investigate dissolution of the pyrodextrins in glycerol/water mixtures, and to determine how crystallinity and birefringence of the pyrodextrins were affected by swelling. Pyrodextrins prepared at pH 3 & 170 °C and pH 2 & 150 °C either dissolved or swelled little in glycerol/water mixtures at 25 °C. In contrast, the pyrodextrin prepared at pH 3 & 150 °C, which showed the least depolymerization, swelled in 40% glycerol to increase granule diameter ~80%. Despite that significant swelling, those swollen granules still displayed a Maltese cross pattern but were amorphous, demonstrating the separation of loss of crystallinity from loss of birefringence.

Three‐state Structural Switching and Selective Molecular Interactions of Cylindrical Concentric Monodomain Liquid Crystal Elastomer

AbstractA cross‐linked poly(acrylate) containing an ethynylhelicene (P)‐pentamer was synthesized by radical polymerization between two horizontally aligned films with a parallel arrangement in trifluoromethylbenzene. The resulting liquid crystal elastomer swollen in bromobenzene showed the Maltese cross, which indicated a cylindrical concentric monodomain structure of the millimeter‐order size as determined by polarized optical microscopy (POM) analysis. In toluene, a homogeneously bright POM image was obtained, which reversibly changed in intensity upon heating and cooling. Addition of an (M)‐tetramer to the liquid crystal elastomer in toluene produced a hetero‐double‐helix exhibiting the Maltese cross, whose intensity did not change upon heating and cooling. The three states can be switched by addition and removal of an (M)‐tetramer and solvents.

Peripheral refraction of myopic eyes with spectacle lenses correction and lens free emmetropes during accommodation

PurposeTo measure axial and off-axis refraction patterns in myopic eyes with spectacle lenses correction and lens free emmetropes in young healthy subjects at different target distances from 2.00 m (0.50 D) to 0.20 m (5.00 D) in terms of sphere, astigmatism, and spherical equivalent refraction.MethodsRefraction was measured at the center, 20 and 40 degrees from the line of sight both nasally and temporally in 15 emmetropic and 25 myopic young healthy subjects with an open field, binocular, infrared autorefractor (Grand Seiko WAM-5500, Hiroshima, Japan). Fixation target was a Maltese cross set at 2.00, 0.50, 0.33 and 0.20 m from the corneal plane. Changes in off-axis refraction with accommodation level were normalized with respect to distance axial values and compared between myopic eyes with spectacle lenses correction and lens free emmetropes.ResultsOff-axis refraction in myopic eyes with spectacle lenses correction was significantly more myopic in the temporal retina compared to lens free emmetropes except for the closest target distance. Relative off-axis refractive error changed significantly with accommodation when compared to axial refraction particularly in the myopic group. This change in the negative direction was due to changes in the spherical component of refraction that became more myopic relative to the center at the 0.20 m distance as the J0 component of astigmatism was significantly reduced in both emmetropes and myopes for the closest target.ConclusionAccommodation to very near targets (up to 0.20 m) makes the off-axis refraction of myopes wearing their spectacle correction similar to that of lens free emmetropes. A significant reduction in off-axis astigmatism was also observed for the 0.20 m distance.

Marangoni Flow Manipulated Concentric Assembly of Cellulose Nanocrystals (Small Methods 11/2021)

Inside Back Cover In article number 2100690, Ye and co-workers report the concentric assembly of cellulose nanocrystals utilizing the Marangoni effect, indicating a uniform Maltese cross optical pattern under linearly polarized light. The assembly and optical property can be readily tuned to “on/off” states by temperature. Combined with 3D printing, it emerges as a promising candidate for information security.

A Novel Mouse Model of Nonalcoholic Steatohepatitis Suggests that Liver Fibrosis Initiates around Lipid-Laden Macrophages

While the interaction of cells such as macrophages and hepatic stellate cells is known to be involved in the generation of fibrosis in nonalcoholic steatohepatitis (NASH), the mechanism remains unclear. This study employed a high-fat/cholesterol/cholate (HFCC) diet to generate a model of NASH-related fibrosis to investigate the pathogenesis of fibrosis. Two mouse strains: C57BL/6J, the one susceptible to obesity, and A/J, the one relatively resistant to obesity, developed hepatic histologic features of NASH, including fat deposition, intralobular inflammation, hepatocyte ballooning, and fibrosis, after 9 weeks of HFCC diet. The severity of hepatic inflammation and fibrosis was greater in A/J mice than in the C57BL/6J mice. A/J mice fed HFCC diet exhibited characteristic CD204-positive lipid-laden macrophage aggregation in hepatic parenchyma. Polarized light was used to visualize the Maltese cross, cholesterol crystals within the aggregated macrophages. Fibrosis developed in a ring shape from the periphery of the aggregated macrophages such that the starting point of fibrosis could be visualized histologically. Matrix-assisted laser desorption/ionization mass spectrometry imaging analysis detected a molecule at m/z 772.462, which corresponds to the protonated ion of phosphatidylcholine [P-18:1 (11Z)/18:0] and phosphatidylethanolamine [18:0/20:2 (11Z, 14Z)], in aggregated macrophages adjacent to the fibrotic lesions. In conclusion, the HFCC diet-fed A/J model provides an ideal tool to study fibrogenesis and enables novel insights into the pathophysiology of NASH-related fibrosis.

Fixational eye movements in passive versus active sustained fixation tasks.

Human fixational eye movements are so small and precise that high-speed, accurate tools are needed to fully reveal their properties and functional roles. Where the fixated image lands on the retina and how it moves for different levels of visually demanding tasks is the subject of the current study. An Adaptive Optics Scanning Laser Ophthalmoscope (AOSLO) was used to image, track and present a variety of fixation targets (Maltese cross, disk, concentric circles, Vernier and tumbling-E letter) to healthy subjects. During these different passive (static) or active (discriminating) tasks under natural eye motion, the landing position of the target on the retina was tracked in space and time over the retinal image directly with high spatial (<1 arcmin) and temporal (960 Hz) resolution. We computed both the eye motion and the exact trajectory of the fixated target's motion over the retina. We confirmed that compared to passive tasks, active tasks elicited a partial inhibition of microsaccades, leading to longer drift periods compensated by larger corrective saccades. Consequently, the overall fixation stability during active tasks was on average 57% larger than during passive tasks. The preferred retinal locus of fixation was the same for each task and did not coincide with the location of the peak cone density.

The retinal and perceived locus of fixation in the human visual system.

Due to the dramatic difference in spatial resolution between the central fovea and the surrounding retinal regions, accurate fixation on important objects is critical for humans. It is known that the preferred retinal location (PRL) for fixation of healthy human observers rarely coincides with the retinal location with the highest cone density. It is not currently known, however, whether the PRL is consistent within an observer or is subject to fluctuations and, moreover, whether observers’ subjective fixation location coincides with the PRL. We studied whether the PRL changes between days. We used an adaptive optics scanning laser ophthalmoscope to project a Maltese cross fixation target on an observer's retina and continuously imaged the exact retinal location of the target. We found that observers consistently use the same PRL across days, regardless of how much the PRL is displaced from the cone density peak location. We then showed observers small stimuli near the visual field location on which they fixated, and the observers judged whether or not the stimuli appeared in fixation. Observers’ precision in this task approached that of fixation itself. Observers based their judgment on both the visual scene coordinates and the retinal location of the stimuli. We conclude that the PRL in a normally functioning visual system is fixed, and observers use it as a reference point in judging stimulus locations.

A Ku-Band Foldable Reflectarray Based on a Maltese-Cross Microstrip Element

Introduction. Reflectarrays have a number of design and functional advantages over their closest analogue - reflector antennas (RA). Although microstrip elements are the most preferred reflectarray elements, single-layer microstrip elements do not allow accurate phase control due to the limited phase adjustment range and a high phase slope. The use of multilayer elements significantly complicates the antenna design and increases its cost. The development of a single-layer element that allows more than 360° phase adjustment and a low phase curve slope is urgent.Aim. To develop a single-layer microstrip phase-correcting element with a phase adjustment range of more than 360° and to design a reflectarray on its basis for operation in satellite communication networks.Materials and methods. Numerical studies were carried out using finite element analysis and the finite-difference time-domain method. Radiation patterns were measured using the near-field scanning method in an anechoic chamber.Results. A phase-correcting element based on a single-layer Maltese cross-shaped microstrip element with close to linear dependence of element size on the phase of the reradiated wave and more than 360° phase adjustment range was developed. On the basis of the investigated element, a foldable reflectarray was designed. The reflector consists of four subarrays, which provide its compact folding for transportation. The results of experimental studies confirmed a high efficiency of the reflectarray, the gain of which is 1.5 dB lower than that of an identical overall dimensions RA in a 7 % operating frequency band. The operating frequency band of the reflectarray in 1 dB gain zone was 11 %.Conclusion. On the basis of a Maltese cross microstrip element, it is possible to implement a single-layer reflectarray with a more than 10 % frequency band. The developed prototype showed the possibility of creating highly efficient foldable reflectarrays for operation in satellite communication and television terminals.

Preparation, adsorption and aggregation behavior of sodium oleyl sulfate with high double bond retention

Sodium oleyl sulfate with high double bond retention of 95.69 % (SOS-95) was successfully prepared by using sulfamic acid as a sulfating reagent, and its structure was identified by Fourier transform infrared (FT-IR) and hydrogen nuclear magnetic resonance spectroscopy (1H NMR). Compared with octadecyl sodium sulfate (OSS) and sodium oleyl sulfate (SOS-77) with double bond retention rate of 77.38 %, the surface properties such as equilibrium surface tension, dynamic surface tension, and dynamic contact angle were analyzed. The results showed that SOS-95 had a lower surface tension (γcmc) of 31.96 mN/m, and the lower critical micelle concentration (CMC) of 0.028 mmol/L. Moreover, it had good adsorption, diffusion and relatively excellent spreading performances, the contact angle can reach as low as 56.87° in 130 s. The aggregation behavior was researched by transmission electron microscopy (TEM), and the sizes of the aggregates were analyzed by dynamic light scattering (DLS). The results showed that sphere-like micelles were formed spontaneously by aqueous solutions of SOS-95 at CMC, and the higher the concentration, the larger the size of the aggregates. Polarized optical microscopy (POM) combined with small Angle X-ray scattering (SAXS) analysis confirmed that lamellar phase liquid crystal structure with Maltese cross flower was formed in aqueous of SOS-95.

Marangoni Flow Manipulated Concentric Assembly of Cellulose Nanocrystals.

Tunable assembly of cellulose nanocrystals (CNCs) is important for a variety of emerging applications in optics, sensing, and security. Most exploited assembly and optical property of CNCs are cholesteric assembly and corresponding circular dichroism. However, it still remains challenge to obtain homogenous and high-resolution cholesteric assembly. Distinct assembly and optical property of CNCs are highly demanded for advanced photonic materials with novel functions. Herein, a facile and programmable approach for assembling CNCs into a novel concentric alignment using capillary flow and Marangoni effect, which is in strike contrast to conventional cholesteric assembly, is demonstrated. The concentric assembly, as quantitatively evidenced by polarized synchrotron radiation Fourier transform infrared imaging, demonstrates Maltese cross optical pattern with good uniformity and high resolution. Furthermore, this Maltese cross can be readily regulated to "on/off" states by temperature. By combining with 3D inkjet technology, a functional binary system composed of "on"/"off" CNCs optical patterns with high spatial resolution, fast printing speed, good repeatability, and precisely controllable optical property is established for information encryption and decryption. This concentric assembly of CNCs and corresponding tunable optical property emerge as a promising candidate for information security, anticounterfeiting technology, and advanced optics.

Manipulating and measuring single atoms in the Maltese cross geometry

Background: Optical microtraps at the focus of high numerical aperture (high-NA) imaging systems enable efficient collection, trapping, detection and manipulation of individual neutral atoms for quantum technology and studies of optical physics associated with super- and sub-radiant states. The recently developed “Maltese cross” geometry (MCG) atom trap uses four in-vacuum lenses to achieve four-directional high-NA optical coupling to single trapped atoms and small atomic arrays. This article presents the first extensive characterisation of atomic behaviour in a MCG atom trap. Methods: We employ a MCG system optimised for high coupling efficiency and characterise the resulting properties of the trap and trapped atoms. Using current best practices, we measure occupancy, loading rate, lifetime, temperature, fluorescence anti-bunching and trap frequencies. We also use the four-directional access to implement a new method to map the spatial distribution of collection efficiency from high-NA optics: we use the two on-trap-axis lenses to produce a 1D optical lattice, the sites of which are stochastically filled and emptied by the trap loading process. The two off-trap-axis lenses are used for imaging and single-mode collection. Correlations of single-mode and imaging fluorescence signals are then used to map the single-mode collection efficiency. Results: We observe trap characteristics comparable to what has been reported for single-atom traps with one- or two-lens optical systems. The collection efficiency distribution in the axial and transverse directions is directly observed to be in agreement with expected collection efficiency distribution from Gaussian beam optics. Conclusions: The multi-directional high-NA access provided by the Maltese cross geometry enables complex manipulations and measurements not possible in geometries with fewer directions of access, and can be achieved while preserving other trap characteristics such as lifetime, temperature, and trap size.

Comparison on physicochemical properties of mung bean flour and isolated starch under different level of high static pressure

AbstractBackground and objectivesMung bean has high nutritional value for consumers, but its native form with poor physicochemical properties limited uses for food production. Mung bean flour (MBF) contains starch and nonstarch components including proteins, lipids, and fibers. Nonstarch components possibly cause the physicochemical properties of MBF to be different from those of mung bean starch (MBS). Thus, effect of high‐hydrostatic pressure (HHP) (300, 450, and 600 MPa) processing on the structural, thermal, pasting, and rheological properties of MBF and MBS was investigated.FindingsResults showed that MBF and MBS exhibited various properties under the same HHP treatment. With increasing pressure, the Maltese cross and relative crystallinity of MBS disappeared more significantly than MBF, indicating more severe gelatinization. Furthermore, MBF was seen to have more short‐range ordered structure than MBS. The peak viscosity (PV), trough viscosity (TV), and breakdown viscosity (BV) of MBF were lower than just the MBS only. MBF contained protein, lipid, and fiber, which could compete with starch to absorb water in the food gel systems, thus hindered the swelling and gelatinization of starches. And amylose–lipid complexes were formed in HHP‐treated MBF which could enhance the gel network cross‐linking, with lower tan δ (loss modulus/storage modulus).ConclusionsNonstarch polymers in MBF might protect starch granules from gelatinization under HHP, obvious differences were observed in the thermal, pasting, and rheological properties between HHP‐treated MBS and MBF, and physicochemical properties were greatly related to structural properties of them.Significance and noveltyOverall, HHP as a nonthermal processing technique has potential to modify legume flour with a range of properties into diverse food products.

Extending the functionality of arrowroot starch by thermally assisted high hydrostatic pressure

The modification of native arrowroot starch (NAS) properties by thermally assisted high hydrostatic pressure (HHP) was investigated. Changes in the structure of the granules were produced by HHP. This was enhanced when HHP was applied together with a temperature increase to 50℃, for 15 or 25 min. Processing at 400 MPa/25℃ had minimal effect. As pressure and/or temperature increased, processed arrowroot starches progressively lost the Maltese cross and granular structure. There was also a decrease in the enthalpy of the gelatinization which occurred between 61.3 and 80.3℃. The relative crystallinity of NAS was reduced, depending on the severity of treatment, by 6.81%–35.74%. A principal components analysis showed a clear trajectory depending on processing conditions. The most severe treatment 650 MPa/50℃ did not produce complete gelatinization. Thermally assisted HHP demonstrated advantages over at 25℃ and produced a physically modified version of the arrowroot starch, with potential as a clean label ingredient. Novelty impact statement This study with arrowroot starch (AS) has revealed a pronounced effect of high hydrostatic pressure (HHP) when applied together with mild temperature (50℃), compared with conventional processes at room temperature, and consequent lowering of onset pressure for structural changes of starch. Modified AS with a several different functionalities may be produced by thermally assisted HHP, whose techno-functional properties correspond well with the measurements of structural order. The results of this work support the industrial potential of this unconventional starch as a clean label ingredient.

Sequential micro-Maltese cross array in the ground beetle Carabus insulicola

The exoskeleton of the ground beetle Carabus insulicola was observed using polarizing optical microscopy (POM) with simultaneous transmitted and reflected light. The surface showed iridescence owing to the periodic microstructure. A Maltese cross array of the inner layer of the elytra was observed. The matrix of the middle layer of the elytra is composed of protein with the arrangement of a cholesteric liquid crystal (CLC)-like helical structure. The scanning electron microscopy observations revealed the layers structure of the exoskeleton of the ground beetle. Synchrotron X-ray diffraction measurement evaluated crystallinity of the exoskeleton. Morphology of the Maltese cross array of the beetle has similarity with synthetic chiral-CLC.

Adjustable positive and negative hygrothermal expansion metamaterial inspired by the Maltese cross.

A metamaterial that can manifest both positive and negative coefficients of moisture and thermal expansion is presented herein, based on inspiration from the Maltese cross. Each unit of the metamaterial consists of a pair of equal-armed crosses pin-joined at their junctions to permit rotation, but elastically restrained by a bimaterial spiral spring, and four pairs of hinge rods to translate the relative rotational motion of the pair of equal-armed crosses into translational motion of the connecting rods. The effective coefficients of moisture and thermal expansion models were developed for small and large changes in the hygrothermal conditions using infinitesimal (approximate) and finite (exact) motion analyses, respectively, with the former giving constant effective coefficients with respect to environmental changes. Results indicate that the approximate method underestimates the magnitude of both the effective expansion coefficients under cooling and drying but overestimates magnitudes of both coefficients during heating and moistening, and that the change in both expansion coefficients is more drastic during cooling and drying than during heating and moistening. In addition to providing another micro-lattice geometry for effecting expansion coefficients of either signs, this metamaterial exhibits auxetic property.