Small Retardation Research Articles

Adsorption and migration behaviors of heavy metals (As, Cd, and Cr) in single and binary systems in typical Chinese soils

In this study, the competitive adsorption and migration behaviors of arsenic (As), cadmium (Cd), and chromium (Cr) in typical Chinese soils were investigated. It was observed that Hainan, Shanxi, and Zhejiang Mengjiadai soils exhibited the highest adsorption capacities for As (563 μg/g), Cd (653 μg/g), and Cr (383 μg/g), respectively. Heavy metals (HMs) adsorption capacities were predicted by Extreme gradient boosting (XGBoost) models, and the Shapley additive explanation (SHAP) was employed to elucidate the effect of soil physicochemical properties on target values. Due to redox and complexation reaction, the primary factor affecting adsorption has changed from free state manganese (Mn) in single As system to antimony (Sb) in As/Cd and As/Cr systems. Furthermore, the maximum adsorption capacity (Qm) of As increased by 49.4 % with the addition of Cd into Heilongjiang soil. Finally, the migration process of HMs in Heilongjiang, Hebei, and Hainan soils was simulated by column experiments. With a relatively large dispersion coefficient (D = 29.630 cm2/h) and small retardation factor (Rh = 0.030), Cr penetrated fastest in Heilongjiang soil. This research demonstrates that both the types and coexistence of HMs may affect the HMs behaviors in soil.

The current state of the problem, clinical-pathogenetic approaches to the diagnosis and management tactics of fetal growth restriction

Fetal growth restriction is a common complication of pregnancy with a complex etiology and limited possibilities of diagnosis and treatment. The relevance of this difficult obstetric problem is determined by various published diagnostic criteria, relatively low detection rates, and limited options for prevention and treatment.Fetal growth restriction is defined as the inability of the fetus to reach its genetically determined growth potential, most often due to abnormal placentation. Forms of fetal growth restriction with early or late onset are distinguished based on the gestational age determined during prenatal ultrasound diagnosis. According to most recommendations, the 32nd week of pregnancy is set as the cut-off point for distinguishing between early and late onset fetal growth restriction.The definition underlying this classification is based on differences between these two phenotypes of fetal growth restriction in severity, natural history, Doppler findings, association with hypertensive complications, placental features, and management. It is important to distinguish two separate conditions: fetal growth restriction and small-for-gestational fetus, which differ in short-term and long-term perinatal outcomes.A fetus is defined as small for gestational age if the estimated weight or weight of the fetus at birth is below the 10th percentile. Fetal growth restriction is diagnosed if the estimated fetal weight is below the 3rd percentile or a combination of pathological blood flow in the umbilical arteries and/or uterine arteries in fetuses with an estimated weight below the 10th percentile. It can also occur in fetuses and newborns with a body weight above the 10th percentile.The need to distinguish between fetal growth restriction and small-for-gestational-age fetus is related to the fact that fetal growth restriction is the main cause of stillbirth, neonatal death, higher perinatal morbidity, as well as increased risk of diseases in adulthood.The article analyzes the approaches to differentiating fetal growth restriction from small growth retardation in terms of fetal gestation period and further increasing the accuracy of diagnosis, as well as the modern concept of pathogenesis, with an emphasis on oxidant stress as a key molecular mechanism of adverse outcomes. Appropriate interventions during pregnancy to reduce perinatal complications should include antenatal monitoring and drug therapy.

Fabrication of a novel MoB/BiOCl photocatalyst for losartan and Escherichia coli removal

In this work, various MoB/BiOCl (0.5–2.0% wt. MoB) photocatalysts were fabricated, characterized using X-ray diffraction, diffuse reflectance spectroscopy, scanning electron microscopy/energy dispersive spectrometer (SEM/EDS) and chronoamperometry, and their photocatalytic activity was assessed for the degradation of the persistent contaminant losartan (LOS) in aqueous solutions under simulated solar irradiation. The 0.5MoB/BiOCl catalyst exhibited the highest efficiency, achieving complete degradation of 500 μg/L LOS in less than 10 min. Interestingly, the 0.5MoB/BiOCl sample also showed remarkable efficiency under visible irradiation (>420 nm), achieving 80% removal in 30 min. The decomposition kinetics followed pseudo-first-order, while the efficiency significantly decreased under alkaline conditions. According to the scavenging experiments, both h+, O2•− and 1O2 participate in the decomposition of LOS, while the role of •OH is minor. A slight increase in degradation was observed in the presence of NaCl, and a small retardation occurred in the presence of humic acid. On the contrary, the presence of bicarbonates significantly delayed the reaction. Although significant inhibition was observed for secondary effluent, the system was capable of completely degrading LOS in less than 15 min when pH was adjusted to 3.8. The process demonstrated promising results for the simultaneous removal of E. coli and micropollutants, achieving complete LOS removal in 15 min and 99.999% inactivation of E. coli after 180 min.

Moving load in an ice channel with a crack

The effect of a crack in the ice cover of a channel on strains and deflections of the ice sheet, which are caused by a load moving along the channel, is investigated. The crack is at the center of the channel. The problem is symmetric with a load moving along the crack at constant speed. The problem is formulated within the linear hydroelastic theory. The fluid in the channel is inviscid and incompressible and its motion is potential. The ice sheets are modeled as viscoelastic thin plates clamped to the walls of the channel. The coupled hydroelastic problem is solved by using the Fourier transform along the channel and the normal mode method across the channel. The effects of the load speeds, depth of the channel, ice thickness and characteristics of the load on the hydroelastic response of the ice sheet are investigated. It is shown that the deflections and strains in the ice sheet strongly depend on the speed of the load with respect to the critical speeds of the hydroelastic waves propagating along the channel. The maximum ice deflection occurs at the critical speed of long waves for relatively large values of the retardation time of ice, and at the critical speed of the lowest hydroelastic wave with minimum phase speed for small retardation time of ice. The strain along the center plane of the channel peaks at the critical speed of long waves for ice sheet without a crack. However, it peaks near the critical speed of the lowest hydroelastic wave with minimum phase speed for ice sheet with a crack. The moving load causes larger strains in the ice cover if the load is elongated along the channel for a given total load and load length. The moving load causes smaller strains in the ice cover if the load is elongated along the channel for a given total load and load width.

Ultrahigh Sensitivity Optical Rotation Detection Based on Reflecting Photo-Elastic Modulation System

The optical rotation detection system (ORDS) based on photo-elastic modulator (PEM) has achieved ultrahigh sensitivities, and further sensitivity improvement requires higher light intensities. However, the relatively large phase retardations in PEM restricts intensity increasing with maximum power limit. In this paper, we propose a novel reflecting modulation method in ORDS which can realize high light intensity detection. In the reflecting system, after passing through the modulator, the light is reflected back to the modulator again. We calculate the Jones matrix of the reflecting modulation system, and find that the matrix keeps unchanged except the peak phase retardations decreases. Because of the smaller retardations, the acceptable incident light intensities increase, which can suppress the influence of the photon shot noise. In the experiment, we demonstrate that the peak phase retardation of a PEM decreases 3.8 times compared with the conventional system, and the probe sensitivity of the magnetometer improves about 1.4 times. The reflecting modulation system can be used in atomic magnetometers and co-magnetometers where small peak retardations are required.

Effect of retardation on the frequency and linewidth of plasma resonances in a two-dimensional disk of electron gas

We theoretically analyze dominant plasma modes in a two-dimensional disk of electron gas by calculating the absorption of an incident electromagnetic wave. The problem is solved in a self-consistent approximation, taking into account electromagnetic retardation effects. We use the Drude model to describe the conductivity of the system. The absorption spectrum exhibits a series of peaks corresponding to the excitation of plasma waves. The position and linewidth of the peaks designating, respectively, the frequency and damping rate of the plasma modes. We estimate the influence of retardation effects on the frequency and linewidth of the fundamental (dipole) and axisymmetric (quadrupole) plasma modes both numerically and analytically. We find the net damping rate of the modes to be dependent on not only the sum of the radiative and collisional decays but also their intermixture, even for small retardation. We show that the net damping rate can be noticeably less than that determined by collisions alone.

Rapid computational cell-rotation around arbitrary axes in 3D with multi-core fiber

Optical trapping is a vital tool in biology, allowing precise optical manipulation of nanoparticles, micro-robots, and cells. Due to the low risk of photodamage and high trap stiffness, fiber-based dual-beam traps are widely used for optical manipulation of large cells. Besides trapping, advanced applications like 3D refractive index tomography need a rotation of cells, which requires precise control of the forces, for example, the acting-point of the forces and the intensities in the region of interest (ROI). A precise rotation of large cells in 3D about arbitrary axes has not been reported yet in dual-beam traps. We introduce a novel dual-beam optical trap in which a multi-core fiber (MCF) is transformed to a phased array, using wavefront shaping and computationally programmable light. The light-field distribution in the trapping region is holographically controlled within 0.1 s, which determines the orientation and the rotation axis of the cell with small retardation. We demonstrate real-time controlled rotation of HL60 cells about all 3D axes with a very high degree of freedom by holographic controlled light through an MCF with a resolution close to the diffraction limit. For the first time, the orientation of the cell can be precisely controlled about all 3D axes in a dual-beam trap. MCFs provide much higher flexibility beyond the bulky optics, enabling lab-on-a-chip applications and can be easily integrated for applications like contactless cell surgery, refractive index tomography, cell-elasticity measurement, which require precise 3D manipulation of cells.

Consistency of splitting frequency difference with longtudinal modes spacing variation in Zeeman dual-frequency laser

Phase anisotropy in laser resonant cavity will bring about an influence on laser frequency and polarization, such as laser frequency splitting, of which the frequency difference is determined by their introduced phase retardation. For a helium-neon laser with a small phase retardation in the cavity, the two split modes are very close to each other whose burned holes are overlapped. Then only one mode oscillates while the other is always in lock-in state due to strong mode competition, which forms hidden frequency split. Meanwhile the spacing between adjacent longitudinal modes deviates from original value and produces a certain variation equal to twice the hidden splitting frequency difference. As a result the longitudinal modes spacing variation is dominated by the phase retardation. On the other hand, by applying transverse magnetic field to a laser tube along the polarization direction, the neon atoms will undergo transverse Zeeman effect and be divided into two groups to provide the gain for polarized light beams parallel to the magnetic field and perpendicular to the magnetic field respectively. Then the laser mode competition is greatly weakened so that the two split modes can oscillate simultaneously to obtain the frequency difference. In order to make profound study of the consistency between longitudinal mode spacing variation and splitting mode frequency difference in the presence of transverse magnetic field, the samples of tilted quartz plate or half wave plate is placed into laser cavity to produce phase retardation. By the two mentioned methods, the splitting frequency difference varying with phase retardation of samples is deduced to make a comparison. Two measurements show that the average relative deviation is less than 1%, while the experimental results accord with theoretical analyses quite well. In this way splitting frequency difference of Zeeman dual-frequency laser can be determined accurately, and a new method to measure the phase retardation of half wave plate is provided.

Polarimetric comparison of fresh and frozen skeletal muscle tissues of goat.

Optical properties can provide rich information about morphology and structure of tissues. Fresh and frozen muscle tissue samples of goat are investigated using imaging polarimetry to understand its structural nature. The outcomes demonstrate that the muscle tissues lose, to some extent, their integrity and organization on freezing. The fresh tissues offer very small circular retardance as compared to frozen samples. However, linear retardance is the main contributor in fresh muscle samples. Ultimately, linear and circular retardance can be used to differentiate fresh and frozen tissues. These investigations illustrate the capabilities of optical polarimetry for the characterization of muscle tissue structures. Specifically, the structure of biological tissue samples can be differentiated using real-time, cost effective and non-invasive optical polarimetry in the field of meat industry and biomedical diagnosis.

A novel detonation arrester containing a large disk with long triangular slits: Design and numerical simulation

AbstractAiming at the problem that common flame arresters can only extinguish deflagration flame, but cannot effectively extinguish detonation flame in large pipelines, this paper proposes a novel structure of detonation arrester based on heat transfer theory to improve the detonation flame extinguishing efficiency. The flame arresting element is composed of a large disk with long triangular slits and is used as the quenching part of detonation arrester in a monolithic structure. Compared with common flame arrester consists of several small fires retarding elements, the proposed monolithic structure is safer due to its integrity. In addition, this paper explores the relationship between flame extinguishing ability, detonation pressure, and temperature change. This investigation determined that the diameter of the quenching part and the parameters(length and height) of the long triangular slits were the key factors affecting the quenching characteristics, and as the diameter and porosity increase, the detonation pressure at the front of the flame arrester will decrease. Finally, the rationality and applicability of the structure are verified by simulation experiments. These preliminary conclusions are helpful to reveal the nature of the proposed structure and solve the technical problem of preventing detonation flame propagation of coal mine gas in large pipelines.

Clinical, cytogenetic, and molecular findings in a patient with ring chromosome 4: case report and literature review

BackgroundSince 1969, 49 cases have been presented on ring chromosome 4. All of these cases have been characterized for the loss of genetic material. The genes located in these chromosomal regions are related to the phenotype.Case presentationA 10-year-old Ecuadorian Mestizo girl with ring chromosome 4 was clinically, cytogenetically and molecularly analysed. Clinical examination revealed congenital anomalies, including microcephaly, prominent nose, micrognathia, low set ears, bilateral clinodactyly of the fifth finger, small sacrococcygeal dimple, short stature and mental retardation. Cytogenetic studies showed a mosaic karyotype, mos 46,XX,r(4)(p16.3q35.2)/46,XX, with a ring chromosome 4 from 75 to 79% in three studies conducted over ten years. These results were confirmed by fluorescence in situ hybridization (FISH). Loss of 1.7 Mb and gain of 342 kb in 4p16.3 and loss of 3 Mb in 4q35.2 were identified by high-resolution mapping array.ConclusionMost cases with ring chromosome 4 have deletion of genetic material in terminal regions; however, our case has inv dup del rearrangement in the ring chromosome formation. Heterogeneous clinical features in all cases reviewed are related to the amount of genetic material lost or gained. The application of several techniques can increase our knowledge of ring chromosome 4 and its deviations from typical “ring syndrome.”

Characteristics of the s–Wave Symmetry Superconducting State in the BaGe3 Compound

Thermodynamic properties of the s–wave symmetry superconducting phase in three selected structures of the BaGe 3 compound ( P 6 3 / m m c , A m m 2 , and I 4 / m m m ) were discussed in the context of DFT results obtained for the Eliashberg function. This compound may enable the implementation of systems for quantum information processing. Calculations were carried out within the Eliashberg formalism due to the fact that the electron–phonon coupling constant falls within the range λ ∈ 0.73 , 0.86 . The value of the Coulomb pseudopotential was assumed to be 0.122 , in accordance with the experimental results. The value of the Coulomb pseudopotential was assumed to be 0.122 , in accordance with the experimental results. The existence of the superconducting state of three different critical temperature values, namely, 4.0 K, 4.5 K and 5.5 K, depending on the considered structure, was stated. We determined the differences in free energy ( Δ F ) and specific heat ( Δ C ) between the normal and the superconducting states, as well as the thermodynamic critical field ( H c ) as a function of temperature. A drop in the H c value to zero at the temperature of 4.0 K was observed for the P 6 3 / m m c structure, which is in good accordance with the experimental data. Further, the values of the dimensionless thermodynamic parameters of the superconducting state were estimated as: R Δ = 2 Δ ( 0 ) / k B T c ∈ { 3.68 , 3.8 , 3.8 } , R C = Δ C ( T c ) / C N ( T c ) ∈ { 1.55 , 1.71 , 1.75 } , and R H = T c C N ( T c ) / H c 2 ( 0 ) ∈ { 0.168 , 0.16 , 0.158 } , which are slightly different from the predictions of the Bardeen–Cooper–Schrieffer theory ( [ R Δ ] B C S = 3.53 , [ R C ] B C S = 1.43 , and [ R H ] B C S = 0.168 ). This is caused by the occurrence of small retardation and strong coupling effects.

Characteristics of the gut microbiota colonization, inflammatory profile, and plasma metabolome in intrauterine growth restricted piglets during the first 12 hours after birth.

Intrauterine growth restriction (IUGR) predisposes newborns to inflammatory and metabolic disturbance. Disequilibrium of gut microbiota in early life has been implicated in the incidence of inflammation and metabolic diseases in adulthood. This study aimed to investigate the difference in gut microbiota colonization, cytokines and plasma metabolome between IUGR and normal birth weight (NBW) piglets in early life. At birth, reduced (P < 0.05) body, jejunum, and ileum weights, as well as decreased (P < 0.05) small intestinal villi and increased (P < 0.05) ileal crypt depth were observed in IUGR piglets compared with their NBW counterparts. Imbalanced inflammatory and plasma metabolome profile was observed in IUGR piglets. Furthermore, altered metabolites were mainly involved in fatty acid metabolism and inflammatory response. At 12 h after birth and after suckling colostrum, reduced (P < 0.05) postnatal growth and the small intestinal maturation retardation (P < 0.05) continued in IUGR piglets in comparison with those in NBW littermates. Besides, the gut microbiota structure was significantly altered by IUGR. Importantly, the disruption of the inflammatory profile and metabolic status mainly involved the pro-inflammatory cytokines (IL-1β and IFN-γ) and amino acid metabolism. Moreover, spearman correlation analysis showed that the increased abundance of Escherichia-Shigella and decreased abundance of Clostridium_sensu_stricto_1 in IUGR piglets was closely associated with the alterations of slaughter weight, intestinal morphology, inflammatory cytokines, and plasma metabolites. Collectively, IUGR significantly impairs small intestine structure, modifies gut microbiota colonization, and disturbs inflammatory and metabolic profiles during the first 12 h after birth. The unbalanced gut microbiota mediated by IUGR contributes to the development of inflammation and metabolic diseases.

Nonlinear electrohydrodynamic instability through two jets of an Oldroydian viscoelastic fluids with a porous medium under the influence of electric field

In the light of the viscous potential theory, a nonlinear instability of the surface waves propagating through two jets of viscoelastic fluids is scrutinized. The flow is jetting through porous media under the action of a uniform axial electric field. The Oldroyd B model is employed to characterize the rheological behavior of the viscoelastic fluid. A weakly nonlinear theory of wave propagation is deemed. A general dispersion relation and neutral curves are addressed and plotted for the different parameters. The Routh-Hurwitz criterion is utilized to determine the stability criteria. Several special cases are reported. It found that, in absence of porous media, the stability happens for large relaxation time and small retardation time. In addition, small retardation time leads to increase the elasticity of the fluid. Therefore, the stability is determined due to the elasticity of the fluid. However, in the presence of porous medium, the elasticity of the fluid decreases with the increase of relaxation time. Thus, the elasticity has a destabilizing effects. Furthermore, fluid viscosity has showed dual role of the stability diagram. Also, the case of Maxwell fluid is illustrated graphically. It is observed that Maxwell model is less stabilizing than Oldroyd model. The method of multiple time scale with the Taylor’s expansion is employed to conduct the well-known Ginzburg-Landau equation, which governs the nonlinear stability of the system. New several regions of stability and instability are identified due to the nonlinear effects.

Full-field Strain Measurements for Microstructurally Small Fatigue Crack Propagation Using Digital Image Correlation Method.

A novel measurement approach is used to reveal the cumulative deformation field at a sub-grain level and to study the influence of microstructure on the growth of microstructurally small fatigue cracks. The proposed strain field analysis methodology is based on the use of a unique pattering technique with a characteristic speckle size of approximately 10 µm. The developed methodology is applied to study the small fatigue crack behavior in body centered cubic (bcc) Fe-Cr ferritic stainless steel with a relatively large grain size allowing a high spatial measurement accuracy at the sub-grain level. This methodology allows the measurement of small fatigue crack growth retardation events and associated intermittent shear strain localization zones ahead of the crack tip. In addition, this can be correlated with the grain orientation and size. Thus, the developed methodology can provide a deeper fundamental understanding of the small fatigue crack growth behavior, required for the development of robust theoretical models for the small fatigue crackpropagation in polycrystalline materials.

199 - Growth defects and metabolic alterations in IDH-1 and G6PD double-deficient Caenorhabditis elegans due to severe imbalance of redox homeostasis

NADPH plays an indispensable role in normal cellular physiology by maintaining redox homeostasis and providing reducing power for reductive biosynthesis. Isocitrate dehydrogenase-1 (IDH1) and glucose 6-phosphate dehydrogenase (G6PD) are the two major NADPH-generating enzymes in cells. Dysfunction of NADPH-generating enzyme results redox imbalance leading to abnormal cellular function and growth retardation. A severe redox imbalance model: G6PD/IDH1 double deficient C. elegans was generated to delineate the importance of redox homeostasis during larval development. The small body size, growth retardation and molting defects were observed in G6PD/IDH1 double-deficient C. elegans, but not in controls including either G6PD or IDH1 deficient C. elegans. The global metabolomics analyses were utilized to assess the effects of severe redox imbalance in metabolic pathways. Principal component analysis (PCA) showed that a distinct pattern of metabolic profile was found in G6PD/IDH1 double-deficient C. elegans as compared to controls. The metabolomic pathway analysis indicated that many of amino acid biosynthetic pathways were altered, especially in those amino acids requiring NADPH for their synthesis. The decreased expression of molting protease NAS-37 during molting in C. elegans might reflect the effects of reduced amino acid level in protein synthesis. Furthermore, the level of MDA and 4-HNE, which are lipid peroxidation markers, were increased in G6PD/IDH1 double-deficient C. elegans. Taken together, these results suggest that G6PD and IDH1 are important to maintain redox homeostasis for normal cellular and physiologic functions.

Simple Method for Measuring Small Retardance

Small retardances are encountered in many experimental works. Internal stresses, weakly birefringent materials, optical windows and formation of contaminating surface layers are sources of small retardances. Most known methods for retardance measurements fail to determine accurately their values which are sometimes essential in the evaluation of experimental results. In this work, we present a method for accurate measurement of a small retardance. Our study aims to find the retardance error in a birefringent full-wave plate which, if perfect, is considered as of zero retardance. Our treatment will make use of a previously presented model for simultaneous calibration of two phase plates.

Microstructurally small fatigue crack propagation and retardation at grain boundary in a polycrystalline Ni-base superalloy

Microstructurally small fatigue crack propagation and retardation at grain boundary in a polycrystalline Ni-base superalloy

Combination of CoWO4 and Ag3VO4 with Fe3O4/ZnO nanocomposites: Magnetic photocatalysts with enhanced activity through p-n-n heterojunctions under visible light

As novel visible-light-induced photocatalysts, a series of magnetically recyclable Fe3O4/ZnO/CoWO4/Ag3VO4 nanocomposites were fabricated through successive combination of Fe3O4/ZnO with CoWO4 and Ag3VO4. A facile refluxing-calcination procedure was employed to prepare these nanocomposites and they were characterized by various sophisticated instruments including XRD, EDX, SEM, TEM, UV–vis DRS, FT-IR, PL, as well as VSM and subsequently tested for photocatalytic degradations of three dyes and one colorless pollutants. The Fe3O4/ZnO/CoWO4/Ag3VO4 (20%) nanocomposite indicated excellent photodegradation for RhB under visible light, which is 78.4, 4.44, and 3.19 times superior to the Fe3O4/ZnO, Fe3O4/ZnO/Ag3VO4, and Fe3O4/ZnO/CoWO4 samples, respectively. Production of more electron-hole pairs due to presence of two small band gap semiconductors and retardation of the charge carriers from recombination due to formation of p-n-n heterojunctions are the main factors enhancing the photocatalytic performance. Additionally, the nanocomposite was readily recovered from the reaction solution using a magnet and its photocatalytic activity remained reasonable after some repetitive cycles.

Jones matrix description of Fabry-Perot interference in a single axis photo-elastic modulator and the consequences for the magneto-optical measurement method

When using a Photo-elastic modulator (PEM) in combination with a coherent light source, in addition to the modulation of the phase, Fabry-Perot interference in the PEM’s optical head induces large offsets in the 1ω and 2ω detector signals. A Jones matrix which describes both effects simultaneously, was derived for a single axis PEM and used to find an expression for the detector signal for two different MO Kerr setups. The effect of the PEM tilt angle, polarizer angle, analyzer angle, and retardation, on the detector signal offsets show that offsets can be zeroed by adjusting PEM tilt angle, polarizer angle, and retardation. This strategy will allow one to avoid large offset drifts due to the small retardation, intensity, and beam direction fluctuations caused by lab temperature fluctuations. In addition, it will enable one to measure in the most sensitive range of the lock-in amplifiers further improving the signal to noise ratio of the setup.