Synthesis, Characterization of α-Oxopentanedioic Acid-Isonicotinoyl (Hydrazone) Rare Earth-Complexes and Relaxivity of Gd-complex

Oxopentanedioic acid isonicotinoyl hydrazone (H_2L) and its five rare earth complexes were synthesized with a view to further investigating MRI activities of the polycarboxylic Schiff base complexes. The complexes were characterized on the basis of elemental analyses, IR, UV, (()~1H) NMR spectra and thermal analyses. The general formula of the complexes is [Ln(HL)(H_2O)_2]Cl_2·H_2O (where Ln(Ⅲ)=La, Pr, Nd, Eu and Gd). In addition, the relaxivity ( R _1) of the Gd-complex was determined by INVREC Au program.

NMR RELAXIVITY AND IMAGING OF NEUTRAL MACROMOLECULAR POLYESTER GADOLINIUM(Ⅲ)COMPLEXES

Five neutral macromolecular polyester gadolinium (Ⅲ) complexes with pendant hydrophobic alkyland aromatic functional groups were prepared. The longitudinal relaxation rates of these complexes weremeasured. One of these Gd (Ⅲ) complexes was chosen for the acute toxicity test and T_1-weighted imagingmeasurement. Preliminary results showed that. compared with Gd-DTPA. the neutral macromoleculargadolinium (Ⅲ) complexes provide higher T_1 relaxivity enhancement and longer function duration.

STUDIES ON THE MAGNETIC RESONANCE CONTRAST AGENTS SYNTHESIS AND SPIN－LATTICE RELAXIVITY OF AMINO ACIDS AND OLIGOPEPTIDYL DERIVATIVES OF GD－DTPA

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Observation of the relaxivity and thickness of surface phase in porous rock with the combination of PFG NMR and relaxation measurements

Nuclear magnetic resonance (NMR) relaxation of fluids in porous media is affected by the solid-liquid interface. Quantitative determination of the surface relaxivity is significantly important for both investigation and application of relaxation mechanisms in porous media. A method to estimate the surface relaxivity with the combination of relaxation and diffusion measurements is proposed. According to this method, a criterion for testing the current diffusion and relaxation theory for porous media is available.

Synthesis and relaxivity of polycarboxylic hydrazone rare earth complexes——Relaxivity of α-oxo-pentanedioic acid benzoyl hydrazone Gd-complexes

Synthesis of ligand, α-oxo-pentanedioic acid benzoyl hydrazone (H2LPB), and its six rare earth (La, Pr, Nd, Sm, Gd and Er) complexes are reported. The composition and the properties of the complexes were characterized by element analysis, thermal analysis, UV, IR and H NMR spectra. Besides, relaxivity (R1) of Gd-complex has been determined by INVREC.Au program, using inversion recovery pulse sequences, R1=8.05 mmol ·L-1 · s-1. The acute toxicity of Gd-complex in animal has also been tested, and the median lethal dose (LD50) is equal to (468.2±30) mg/kg.

Interfacial DMI in Fe/Pt thin films grown on different buffer layers

We study the interfacial Dzyaloshinskii-Moriya interactions(i-DMI)of Fe/Pt bilayers grown on Si substrates with MgO,SiO_(2),or Ta each as a buffer layer on the basis of wave-vector-resolved Brillouin light scattering(BLS)measurement.The obtained i-DMI energy values for Fe/Pt on MgO,Ta,and SiO_(2) buffer layers are 0.359,0.321,and 0.274 mJ/m~2,respectively.The large i-DMI value observed in Fe/Pt system on the MgO buffer layer can be attributed to the good interfacial quality and the Rshaba effect at the MgO/Fe interface.Moreover,the MgO/Fe/Pt system,benefiting from better sample quality,exhibits a lower damping factor.Furthermore,layer-resolved first-principles calculations are carried out to gain a more in-depth understanding of the origin of the i-DMI in the Fe/Pt system.The results indicate that in the Fe(110)/Pt(111)system,the substantial DMI energy between Fe spins at the interface is related to a significant change in spin-orbit coupling(SOC)energy in the neighboring Pt layer.In contrast,for the MgO(002)/Fe(002)system,both the DMI and its related SOC energy are concentrated at the interfacial Fe layer.Our investigation will provide a valuable insight into the spintronic community in exploring novel devices with chirality dependence.

Interaction between Surface Acoustic Wave and Quantum Hall Effects

Surface acoustic wave(SAW)is a powerful technique for investigating quantum phases appearing in twodimensional electron systems.The electrons respond to the piezoelectric field of SAW through screening,attenuating its amplitude,and shifting its velocity,which is described by the relaxation model.In this work,we systematically study this interaction using orders of magnitude lower SAW amplitude than those in previous studies.At high magnetic fields,when electrons form highly correlated states such as the quantum Hall effect,we observe an anomalously large attenuation of SAW,while the acoustic speed remains considerably high,inconsistent with the conventional relaxation model.This anomaly exists only when the SAW power is sufficiently low.

Solid-state impedance spectroscopy studies of dielectric properties and relaxation processes in Na_(2)O–V_(2)O_(5)–Nb_(2)O_(5)–P_(2)O_(5) glass

Solid-state impedance spectroscopy(SS-IS)was used to investigate the influence of structural modifications resulting from the addition of Nb2O5 on the dielectric properties and relaxation processes in the quaternary mixed glass former(MGF)system 35Na_(2)O–10V_(2)O_(5)–(55-x)P_(2)O_(5)–xNb_(2)O_(5)(x=0–40,mol%).The dielectric parameters,including the dielectric strength and dielectric loss,are determined from the frequency and temperature-dependent complex permittivity data,revealing a significant dependence on the Nb2O5 content.The transition from a predominantly phosphate glass network(x<10,region I)to a mixed niobate–phosphate glass net-work(10≤x≤20,region II)leads to an increase in the dielectric parameters,which correlates with the observed trend in the direct-cur-rent(DC)conductivity.In the predominantly niobate network(x≥25,region III),the highly polarizable nature of Nb5+ions leads to a fur-ther increase in the dielectric permittivity and dielectric strength.This is particularly evident in Nb-40 glass-ceramic,which contains Na_(13)Nb_(35)O_(94) crystalline phase with a tungsten bronze structure and exhibits the highest dielectric permittivity of 61.81 and the lowest loss factor of 0.032 at 303 K and 10 kHz.The relaxation studies,analyzed through modulus formalism and complex impedance data,show that DC conductivity and relaxation processes are governed by the same mechanism,attributed to ionic conductivity.In contrast to glasses with a single peak in frequency dependence of imaginary part of electrical modulus,M″(ω),Nb-40 glass-ceramic exhibits two distinct contributions with similar relaxation times.The high-frequency peak indicates bulk ionic conductivity,while the additional low-fre-quency peak is associated with the grain boundary effect,confirmed by the electrical equivalent circuit(EEC)modelling.The scaling characteristics of permittivity and conductivity spectra,along with the electrical modulus,validate time-temperature superposition and demonstrate a strong correlation with composition and modification of the glass structure upon Nb_(2)O_(5) incorporation.

Photosynthetic response dynamics in the invasive species Tithonia diversifolia and two co-occurring native shrub species under fluctuating light conditions

To determine the invasiveness of invasive plants,many studies have compared photosynthetic traits or strategies between invasive and native species.However,few studies have compared the photosynthetic dynamics between invasive and native species during light fluctuations.We compared photosynthetic induction,relaxation dynamics and leaf traits between the invasive species,Tithonia diversifolia and two native species,Clerodendrum bungei and Blumea balsamifera,in full-sun and shady habitats.The photosynthetic dynamics and leaf traits differed among species.T.diversifolia showed a slower induction speed and stomatal opening response but had higher average intrinsic water-use efficiency than the two native species in full-sun habitats.Thus,the slow induction response may be attributed to the longer stomatal length in T.diversifolia.Habitat had a significant effect on photosynthetic dynamics in T.diversifolia and B.balsamifera but not in C.bungei.In shady habitat,T.diversifolia had a faster photosynthetic induction response than in full-sun habitat,leading to a higher average stomatal conductance during photosynthetic induction in T.diversifolia than in the two native species.In contrast,B.balsamifera had a larger stomatal length and slower photosynthetic induction and relaxation response in shady habitat than in full-sun habitat,resulting in higher carbon gain during photosynthetic relaxation.Nevertheless,in both habitats,T.diversifolia had an overall higher carbon gain during light fluctuations than the two native species.Our results indicated that T.diversifolia can adopt more effective response strategies under fluctuating light environments to maximize carbon gain,which may contribute to its successful invasion.

Improved Twin Support Vector Machine Algorithm and Applications in Classification Problems

The distribution of data has a significant impact on the results of classification.When the distribution of one class is insignificant compared to the distribution of another class,data imbalance occurs.This will result in rising outlier values and noise.Therefore,the speed and performance of classification could be greatly affected.Given the above problems,this paper starts with the motivation and mathematical representing of classification,puts forward a new classification method based on the relationship between different classification formulations.Combined with the vector characteristics of the actual problem and the choice of matrix characteristics,we firstly analyze the orderly regression to introduce slack variables to solve the constraint problem of the lone point.Then we introduce the fuzzy factors to solve the problem of the gap between the isolated points on the basis of the support vector machine.We introduce the cost control to solve the problem of sample skew.Finally,based on the bi-boundary support vector machine,a twostep weight setting twin classifier is constructed.This can help to identify multitasks with feature-selected patterns without the need for additional optimizers,which solves the problem of large-scale classification that can’t deal effectively with the very low category distribution gap.

Universal basis underlying temperature, pressure and size induced dynamical evolution in metallic glass-forming liquids

The dramatic temperature-dependence of liquids dynamics has attracted considerable scientific interests and efforts in the past decades, but the physics of which remains elusive. In addition to temperature, some other parameters, such as pressure, loading and size, can also tune the liquid dynamics and induce glass transition, which makes the situation more complicated. Here, we performed molecular dynamics simulations for Ni_(50)Zr_(50) bulk liquid and nanodroplet to study the dynamics evolution in the complex multivariate phase space, especially along the isotherm with the change of pressure or droplet size. It is found that the short-time Debye–Waller factor universally determines the long-time relaxation dynamics no matter how the temperature, pressure or size changes. The basic correlation even holds at the local atomic scale. This finding provides general understanding of the microscopic mechanism of dynamic arrest and dynamic heterogeneity.

Analytical solutions to the precession relaxation of magnetization with uniaxial anisotropy

Based on the Landau-Lifshitz-Gilbert(LLG)equation,the precession relaxation of magnetization is studied when the external field H is parallel to the uniaxial anisotropic field H_(k).The evolution of three-component magnetization is solved analytically under the condition of H=nH_(k)(n=3,1 and 0).It is found that with an increase of H or a decrease of the initial polar angle of magnetization,the relaxation time decreases and the angular frequency of magnetization increases.For comparison,the analytical solution for H_(k)=0 is also given.When the magnetization becomes stable,the angular frequency is proportional to the total effective field acting on the magnetization.The analytical solutions are not only conducive to the understanding of the precession relaxation of magnetization,but also can be used as a standard model to test the numerical calculation of LLG equation.

Response optimization of a three-axis sensitive SERF magnetometer for closed-loop operation

Most triaxial-vectorial magnetic field measurements with spin-exchange relaxation free(SERF)atomic magnetometer(AM)are based on the quasi-steady-state solution of the Bloch equation.However,the responding speed of these methods is greatly limited because the frequency of the modulation signal should be slow enough to ensure the validity of the quasi-steady-state solution.In this work,a new model to describe the response of the three-axis sensitive SERF AM with high modulation frequency is presented and verified.The response of alkali-atomic spin to high-frequency modulation field is further investigated by solving the Bloch equation in a modulation-frequency-dependence manner.This solution is well verified by our experiments and can offer a reference for selection of modulation frequencies.The result shows a potential to achieve a SERF AM operating in a geomagnetic field without heavy aluminum shielding when the modulation frequencies are selected properly.

Surgical approaches to correct corneal astigmatism at time of cataract surgery: a mini-review

Among refractive errors,astigmatism is the most common optical aberration,where refraction changes in different meridians of the eye.It causes blurred vision at any distance and includes corneal,lenticular,and retinal astigmatism.Cataract surgery used to cause a progressive increase in the pre-exisiting corneal astigmatism because of creating a surgically induced astigmatism,for example,a large size surgery incision.The development of surgical techniques during last decades has made cataract surgery interchange to treat preoperative corneal astigmatism at time of surgery.Nowadays,three surgical approaches can be used.By placing a sutureless clear corneal incision on the steep meridian of the cornea,a preoperative corneal astigmatism less than 1.0 D can be corrected.Single or paired peripheral corneal relaxing incisions(PCRIs)provide 1.0-3.0 D corneal astigmatism correction.PCRIs are typically used for treating 1.0-1.5 D of regular corneal astigmatism,if more than 2.0 D,the risk of overcorrection and irregular astigmatism is increased.When toric intraocular lenses(IOLs)are unavailable in markets,PCRIs are still a reasonable option for patients with up to 3.0 D of pre-existing corneal astigmatism.Toric IOLs implantation can correct 1.0-4.5 D of corneal astigmatism.Several IOLs are approved to correct a high degree of corneal astigmatism with cylinder power up to 12.0 D.These approaches can be used alone or in combination.

Synthesis and relaxivity of Gd(Ⅲ), Fe(Ⅲ) and Mn(Ⅱ) complexes with dihydropyridine derivative of diethvlenetriaminepentaacetic acid

A novel ligand of DTPA-dihydropyridine derivative was synthesized by reaction of DTPA-dianhydride with 4-aniline-1,4-dihydropyridine. Its complexes of gadolinium, manganese and iron were prepared. Their spin-lattice relaxivities (T1) were investigated. The results show that the NMR T1 relaxivitives (R1) for complexes of Fe(Ⅲ), Mn(Ⅱ) are less than that of Gd(Ⅲ) complex,which has a high relaxivity (R1) on the surrounding water protons, indicating that the Gd(Ⅲ) complex possesses the precondition to be contrast agents for magnetic resonance imaging.

Structural Characterization and Relaxivity Study of a New Paramagnetic Mn（Ⅱ） Complex of DTPA-BpABA

X-ray single crystal analysis of a new paramagnetic manganese（Ⅱ） complex with DTPA-BpABA （a DTPAbisamide derivative）, Mn（DTPA-BpABA）·4H2O, shows that four oxygen atoms and three nitrogen atoms from the ligand coordinate to Mn（Ⅱ） cation, forming a seven-coordinate distorted pentagonal bipyramid polyhedron. In the crystal, the carboxyl groups and the nitrogen atoms extensively form hydrogen bonds with the lattice water molecules, building a 3D-network. The relaxometric study indicates that the R1 value of the paramagnetic manganese（Ⅱ）complex is 5.12 mmol·L·s^-1. The higher R1 value means that this complex may find an application in magnetic resonance imaging （MRI） technique.

Wearable Inflatable Massage Chair:The Future of Comfort

With the continuous advancement of science and technology,our lifestyles are undergoing significant changes,with wearable technology emerging as a captivating trend.In this digital era,there is a growing demand for solutions that cater to people’s needs for health and comfort.The wearable inflatable massage chair represents one such innovation designed to meet these evolving needs.This project is focused on creating a“wearable and portable massage chair”that is both convenient and lightweight.It serves as a massage solution particularly beneficial for the elderly and sedentary individuals.This innovative chair can be used by the elderly during outings or errands,as well as by office workers on business trips,while driving,or commuting via subway.Users can simply lean against the seat or a wall,enjoying moments of relaxation amid the busy and fast-paced modern era.

Improved Algorithm for Efficient Extraction of Relaxation Parameter Values from Wideband Permittivity of Baijiu

The complex permittivity of baijiu varies with frequency,and dielectric spectroscopy has been used to evaluate the quality.To simplify the analysis and reduce the number of the parameters,a dielectric relaxation model is often used to fit the permittivity data.However,existing fitting methods such as the least squares and particle swarm optimization methods are often computationally complex and require preset initial values.Therefore,a simpler calculation method of the relaxation parameters considering the geometric characteristics of the permittivity spectrum is proposed.It is based on the relationship between the Cole-Cole relaxation parameters and the Cole-Cole diagram,which is fitted by a geometric method.First,the concepts of the Cole-Cole parameters and the diagram are introduced,and then the process of obtaining the parameters from the complex permittivity measurement data is explained.Taking baijiu with 56%alcohol by volume(ABV)as an example,the fitting is better than the least squares method and similar to the particle swarm optimization.This method is then used for the parameter fitting of baijiu with ABV of 42-52%,and the average error is less than 1%,demonstrating its wider applicability.Finally,a prediction model is used for baijiu with 53%ABV,and the error is only 1.51%.Hence,the method can be applied to the measurement of ABV of baijiu.

Effects of relaxation breathing exercise on fatigue and cortisol level among Indonesian gynecological cancer patients undergoing chemotherapy:a pilot study

Objective:This study aimed to determine the effect of the relaxation breathing exercise(RBE)on fatigue and cortisol levels among Indonesian women with gynecological cancer undergoing chemotherapy.Methods:This pilot study consecutively recruited 44 gynecological cancer patients to receive RBE(22)or usual care(22).Cortisol level was measured before and after completion of the intervention(day 8).Fatigue was measured using the Piper Fatigue Scale(PFS).Anxiety and depression were assessed using the Hospital Anxiety and Depression Scale(HADS)at the baseline days of the study for days 1,4,and 8.The obtained data were analyzed using Fisher’s exact test,the independent t-test,and the Mann-Whitney U test.Results:There were significant increases in cortisol levels within the groups,either the intervention or control groups,respectively(P-value=0.0003 and 0.001).Despite there being no statistical significance between the intervention and control groups,there were noticeable differences in the cortisol levels,indicating the extreme increase in cortisol levels in the control group(Median[IQR1-IQR3]:2.30[0.99-9.09];Min-Max:0.43-23.38)compared with the intervention group(Median[IQR1-IQR3]=2.97[1.26-5.18];Min-Max=0.39-6.91).Conclusions:RBE helps prevent a significant increase in cortisol levels that can alleviate fatigue for women with gynecological cancer.Further research was recommended to compare several intervention modalities for fatigue and cancer-related symptom management based on cortisol level changes.

Photoelectric State with Long-Term Relaxation in CdTe:(Ag, Cu, Cd) and Sb2Se3:Se Photovoltaic Films

The results of an experimental study of long-term relaxation of the photoelectret state of polycrystalline CdTe:(Ag, Cu, Cd) and Sb2Se3:Se films with an anomalous photovoltaic property are presented. In such films, the residual photovoltage is caused by the separation of photocarriers by the built-in electrostatic field of the near-surface region of space charges and their asymmetric capture by deep levels of impurities or complexes, including impurity atoms and intrinsic defects, both in the bulk and on the surface of crystal grains. It has been shown that in activated films, a two-step exponential temporary relaxation of the initial photovoltage of the order of VAPV ≈ (500-600) V is detected, and only 10% of it experiences long-term relaxation (t ≈ 100-120 min).