Neural mechanism of acupuncture-modulated gastric motility

AIM: To investigate the acupuncture-modulated gastric motility and its underlying neural mechanism.METHODS: Intragastric pressure and/or waves of gastric contraction in rats were recorded by intrapyloric balloon and changes of gastric motility induced by acupuncture stimulation were compared with the background activity before any stimulation. Gastro-vagal or splanchnic-sympathetic nerves were recorded or cut respectively for investigating the involvement of autonomic nerve pathways. Spinalization experiment was also performed.RESULTS: Acupuncture-stimulation by exciting Aδ and/or C afferent fibers, could only modulate gastric motility. Acupuncture-stimulation on fore- and hind-limbs evoked a moderate gastric motility followed by increased vagus discharges with unchanged sympathetic activity, while the same stimulus to the acupoints in abdomen resulted in reversed effects on gastric motility and autonomic nervous activities. The inhibitory gastric response was completely abolished by splanchnic denervation, but the facilitative gastric response to stimulation of acupoints in limbs was not influenced, which was opposite to the effect when vagotomy was performed. The similar depressive effects were produced by the stimulation at the acupoints homo-segmental to the gastric innervation in the animals with or without spinalization. However, the facilitation induced by the stimulation at the acupoints hetero-segmental to the gastric innervation was not observed in the spinalized animals.CONCLUSION: Facilitative effects of stimulating hetero-segmental acupoints are involved in the intact preparation of vagal nerves and spinal cord, while the inhibitory response induced by stimulating homo-segmental acupoints is involved in the intact preparation of sympathetic nerves. Only the acupuncture-stimulation with intensity over the threshold of Aδ and/or C afferent fibers can markedly modulate gastrointestinal motility.

Effective regularity in modulation on gastric motility induced by different acupoint stimulation

AIM: To investigate whether manual acupuncture at representative acupoints in different parts of the body can modulate responses of gastric motility in rats and regular effects in different acupoint stimulation.METHODS: The gastric motor activity of rats was recorded by the intrapyloric balloon. The changes of gastric motility induced by the stimulation were compared with the background activity in intragastric pressure and/or waves of gastric contraction recorded before any stimulation. Morphological study was also conducted by observing the Evans dye extravasation in the skin after mustard oil injection into the intragastric mucous membrane to certify cutaneous innervations of blue dots related to gastric segmental innervations. RESULTS: In all six rats that received mustard oil injections into intragastric mucosa, small blue dots appeared in the skin over the whole abdomen, but mainly in peri-midline upper- and middle- abdomen and middle-back, a few in thigh and groin. It may speculate that cutaneous innervations of blue dots have the same distribution as gastric segmental innervations. Acu-stimulation in acupoints of head-neck, four limbs, upper chest-dorsum and lower-dorsum induced markedly augmentation of gastric motility (acupoints on head-neck such as St-2: n = 16, 105.19 ± 1.36 vs 112.25 ± 2.02 and St-3: n = 14, 101.5 ± 1.75 vs 109.36 ± 1.8; acupoints on limbs such as Sp-6: n = 19, 100.74 ± 1.54 vs 110.26 ± 3.88; St-32: n = 17, 103.59 ± 1.64 vs 108.24 ± 2.41; St-36: n = 16, 104.81 ± 1.72 vs 110.81 ± 2.74 and Li-11: n = 17, 106.47 ± 2.61 vs 114.77 ±3.77, P < 0.05-0.001). Vigorous inhibitory regulations of gastric motility induced by acu-stimulation applied in acupoints on whole abdomen and middle-dorsum were significantly different as compared with the controls before acu-stimulation (abdomen acupoints such as Cv-12: n = 11, 109.36 ± 2.09 vs 101 ± 2.21; Cv-6: n = 18, 104.39 ± 1.42 vs 91.83 ± 3.22 and St-21: n = 12, 107 ± 2.97 vs 98.58 ± 2.81; acupoints on middle-dorsum such as Bl-17: n = 19, 100.63 ± 1.4 vs 92.21 ± 2.07 and Bl-21: n = 19, 103.84 ± 1.48 vs 97.58 ± 2.16, P < 0.05-0.001).CONCLUSION: Regular regulatory effects of facilitation and inhibition on gastric motility appear to be somatotopically organized in the acupoints of whole body, and the effective regularity of site-special acupoints on gastric motility is involved in segmental innervations between stomach and acupoints.

Adhesion behavior of endothelial progenitor cells to endothelial cells in simple shear flow

The adhesion of endothelial progenitor cells（EPCs） on endothelial cells（ECs） is one of the critical physiological processes for the regenesis of vascular vessels and the prevention of serious cardiovascular diseases.Here,the rolling and adhesion behavior of EPCs on ECs was studied numerically.A two-dimensional numerical model was developed based on the immersed boundary method for simulating the rolling and adhesion of cells in a channel flow.The binding force arising from the catch bond of a receptor and ligand pair was modeled with stochastic Monte Carlo method and Hookean spring model.The effect of tumor necrosis factor alpha（TNF-α） on the expression of the number of adhesion molecules in ECs was analyzed experimentally.A flow chamber system with CCD camera was set up to observe the top view of the rolling of EPCs on the substrate cultivated with ECs.Numerical results prove that the adhesion of EPC on ECs is closely related to membrane stiff-ness of the cell and shear rate of the flow.It also suggests that the adhesion force between EPC and EC by P-selectin glycoprotein ligand-1 only is not strong enough to bond the cell onto vessel walls unless contributions of other catch bond are considered.Experimental results demonstrate that TNF-α enhanced the expressions of VCAM,ICAM,P-selectin and E-selectin in ECs,which supports the numerical results that the rolling velocity of EPC on TNF-α treated EC substrate decreases obviously compared with its velocity on the untreated one.It is found that because the adhesion is affected by both the rolling velocity and the deformability of the cell,an optimal stiffness of EPC may exist at a given shear rate of flow for achieving maximum adhesion rates.

Enhanced optical molasses cooling for Cs atoms with largely detuned cooling lasers

We report a detailed study of the enhanced optical molasses cooling of Cs atoms,whose large hyperfine structure allows to use the largely red-detuned cooling lasers.We find that the combination of a large frequency detuning of about-110 MHz for the cooling laser and a suitable control for the powers of the cooling and repumping lasers allows to reach a cold temperature of^5.5μK.We obtain 5.1×10^7 atoms with the number density around 1×10^12 cm^-3.Our result gains a lower temperature than that got in other experiments,in which the cold Cs atoms with the temperature of^10μK have been achieved by the optical molasses cooling.

Molecular phylogeny and taxonomy of four Remanella species(Protozoa, Ciliophora): A flagship genus of karyorelictean ciliates, with descriptions of two new species

During faunal studies of psammophilic ciliates along the coast of Qingdao, China, several marine karyorelictean species were isolated. Among them,four species within the genus Remanella were investigated, including two species new to science:i.e., R. rugosa, Remanella elongata sp. nov.,Remanella aposinica sp. nov.,and R.unicorpusculata. Remanella rugosa has been reported several times, but this study is the first to provide detailed morphological characters and phylogenetics. Remanella elongata sp. nov. can be distinguished from its congeners by the presence of complex cortical granules, fewer macronuclei, and longer body size. Remanella aposinica sp. nov.differs from its congeners by having 14–17 right lateral ciliary rows and 24–37 dikinetids of intrabuccal kinety. Poorly known Remanella rugosa var. unicorpusculata(Kahl, 1933) Foissner, 1996should be elevated from subspecies to species level,Remanella unicorpusculata(Foissner, 1996) stat.nov., based on detailed redescriptions with statistical data, living morphology, infraciliature, and species definitions. Small subunit(SSU) rDNA was sequenced for the four species, and phylogenetic analysis revealed that all known taxa in Remanella formed the outline branch to the genus Loxodes with moderate to high bootstrap support among Remanella lineages.

Alanine racemase is essential for the growth and interspecies competitiveness of Streptococcus mutans

D-alanine （D-Ala） is an essential amino acid that has a key role in bacterial unique enzyme that interconverts L-alanine and D-alanine in most bacteria, antimicrobial drug development. Streptococcus mutans is a major causative cell wall synthesis. Alanine racemase （Air） is a making this enzyme a potential target for factor of dental caries. The factors involved in the survival, virulence and interspecies interactions of S. mutans could be exploited as potential targets for caries control. The current study aimed to investigate the physiological role of Air in S. mutans. We constructed air mutant strain of S. mutans and evaluated its phenotypic traits and interspecies competitiveness compared with the wild-type strain. We found that air deletion was lethal to S. mutans. A minimal supplement of D-Ala （150 pg.mL- 1） was required for the optimal growth of the air mutant. The depletion of D-alanine in the growth medium resulted in cell wall perforation and cell lysis in the air mutant strain. We also determined the compromised competitiveness of the air mutant strain relative to the wild-type S. mutans against other oral streptococci （S. sanguinis or S. gordonil~, demonstrated using either conditioned medium assays or dual-species fluorescent in situ hybridization analysis. Given the importance and necessity of air to the growth and competitiveness of S. mutans, Air may represent a promising target to modulate the cariogenicity of oral biofilms and to benefit the management of dental caries.

Efficient loading of ultracold sodium atoms in an optical dipole trap from a high power fiber laser

We report on a research of the loading of ultracold sodium atoms in an optical dipole trap,generated by two beams from a high power fiber laser.The effects of optical trap light power on atomic number,temperature and phase space density are experimentally investigated.A simple theory is proposed and it is in good accordance with the experimental results of the loaded atomic numbers.In a general estimation,an optimal value for each beam with a power of 9 W from the fiber laser is achieved.Our results provide a further understanding of the loading process of optical dipole trap and laid the foundation for generation of a sodium Bose–Einstein condensation with an optical dipole trap.

Enhancement of the photoassociation of ultracold atoms via a non-resonant magnetic field

We report an effective method for enhancing the photoassociation of ultracold atoms using a non-resonant magnetic field,which enables the manipulation of the coupling between the wavefunctions of the colliding atomic pairs and the excited molecules.A series of photoassociation spectra are measured for different magnetic fields.We show that the photoassociation rate is significantly dependent on the non-resonant magnetic field.A qualitatively theoretical explanation is provided,and shows a good agreement with the experimental result.

Micromagnetism simulation on effects of soft phase size on Nd2Fe14B/α-Fe nanocomposite magnet with soft phase imbedded in hard phase

In this study, micromagnetism simulation by using timte dltterence method is cameo out on the Ncl21-el415/a-Fe nanocomposite magnet with soft phase imbedded in hard phase. The effects of soft magnetic phase size （S） on the magnetic properties and magnetic reversal modes are systematically analyzed. As S increases from 1 nm to 48 nm, the remanence （Jr） increases, while the coercivity （Hci） decreases, leading to the result that the magnetic energy prod- uct [（BH）max] first increases slowly, and then decreases rapidly, peaking at S = 24 nm with the （BH）max of 72.9 MGOe （1 MGOe = 7.95775 kJ.m-3）. Besides, with the increase of S, the coercivity mechanism of the nanocomposite magnet changes from nucleation to pinning. Furthermore, by observing the magnetic moment evolution in demagnetization pro- cess, the magnetic reversal of the soft phase in the nanocomposite magnet can be divided into three modes with the increase of S： coherent rotation （S 〈 3 nm）, quasi-coherent rotation （3 nm≤S 〈 36 nm）, and the vortex-like rotation （S ≥36 nm）.

Expedient Synthesis of Ketones via N-Heterocyclic Carbene/ Nickel-Catalyzed Redox-Economical Coupling of Alcohols and Alkynest

Summary of main observation and conclusion An A/-heterocyclic carbene/nickel-catalyzed direct coupling of alcohols and internal alkynes to form a-branched ketones has been developed.This methodology provides a new approach to afford branched ketones,which are difficult to access through the hydroacylation of simple internal alkenes with aldehydes.This redox-neutral and redox-economical coupling is free from any oxidative or reductive additives as well as stoichiometric byproducts.These reactions convert both benzylic and aliphatic alcohols and alkynes,two basic feedstock chemicals,into various a-branched ketones in a single chemical step.

Light-induced frequency shifts for the lowest vibrational levels of ultracold Cs2 in the molecular pure long-range 0^-g state

The light-induced frequency shift(LIFS)of ultracold molecular ro-vibrational levels originates from the strong coupling of the atomic-scattering state and the bound-molecular state.In this paper,we present our experimental determination of the LIFSs of the lowest vibrational levels(v=0,1)in the purely long-range 0^-g state of ultracold cesium molecules.A high-resolution double photoassociation spectroscopy is developed,which serves as frequency ruler to measure the frequency shifts of the lowest molecular levels for Cs2.The experimental results are qualitatively consistent with the theoretical expectations.

Structure and magnetic properties of nanocrystalline dysprosium powders

In this current study,nanocrystalline Dy powders were prepared by melt-spinning and subsequent highenergy ball-milling.The effect of ball-milling time on the structure and magnetic properties of the powders was studied.The crystal structure and microstructure of the melt-spun ribbons and ball-milled powders were observed by X-ray diffraction(XRD),scanning electron microscopy(SEM)and transmission electron microscopy(TEM).Magnetic measurement of all samples was performed with vibrating sample magnetometer(VSM).XRD results indicate that the average crystal grain size of the powders decreases from 90.09 nm of the ribbons to 10.42 nm of the4-h ball-milled powders.Further TEM observation shows that the grains are fine and uniform.The Neel temperature(TN)decreases from 182 K of the ribbons to 172 K of the powders,while the Curie temperature(TC)increases from100 to 130 K,demonstrating that the grain size has substantial influence on the magnetic transition process.Moreover,at 60 K,as the ball-milling time increases,the coercivity of the powders increases first,peaking at 0.48 T for 2-h milling,then drops again,while the remanence of the powders decreases monotonic ally.As a result,the powders milled for 2 h exhibit an optimal maximum energy product of 64.0 kJ·m-3,demonstrating the good potential of these powders as a permanent magnet at low temperatures.

小角中子散射技术及其在大分子结构表征中的应用

小角中子散射(SANS)是一种表征从纳米到微米尺寸物质特征结构的有力工具,配合中子的强穿透性和同位素辨识等特性,在软物质大分子结构表征方面发挥着独特的作用.随着中国散裂中子源(CSNS)在2018年正式对外接受机时申请,国内SANS用户群逐年扩大.本文首先简要介绍小角中子散射技术的基本原理、谱仪结构和实验技巧,然后紧扣小角谱仪的特点和方法学方面的最新进展,介绍小角中子散射在高分子溶液、高分子共混物和复合材料、高分子结晶、凝胶、多孔材料、生物大分子等研究领域的结构表征方面的典型应用.小角中子散射和其他表征手段,如小角X射线散射(SAXS)相互紧密配合和补充,成为连接大分子内部多相多尺度的微观结构和宏观性的桥梁.

Origin of low coercivity of high La-Ce-containing Nd-Fe-B sintered magnets

The origin of low coercivity of high La-Cecontaining Nd-Fe-B sintered magnets was analyzed based on characterization of the microstructure,magnetic domain structure,and magnetization reversal process.It can be found that the coercivity of magnet decreases sharply and the ratio value of coercivity(H_(cj))to anisotropic field(H_(A))is below the theoretical value when the amount of La-Ce substitution for Nd is more than 40 wt%.The grain boundaries with poor magnetic isolation in the high La-Cecontaining Nd-Fe-B sintered magnets play an important role in reducing the coercivity of the magnet.In addition,a larger proportion of the reversible portions can be found for the magnet with a large content of La-Ce,which will lead to the low performance of the magnet.

Structure and intrinsic magnetic properties of Sm_(1-x)Pr_xCo_5(x=0–0.6) compounds

In this work, the effects of Pr content on the structure and intrinsic magnetic properties of Sml-xPrxCO5 （x = 0-0.6） compounds prepared by induction melting were systematically investigated by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and magnetic measurements. Microstructural observation and chemical composition analysis show that Sml xPrxCos compounds are composed of （Sin, Pr）Co （1：5） phase and （Sm, Pr）-rich grain boundary phase. XRD results show that all the Sml-xPrxCO5 compounds have a （Sm, Pr）lCo main phase with the hexagonal CaCus-type crystal structure and the （Sm, Pr）2 Co7 impurity phase. In addition, the detailed research shows that the lattice constants （a, c） and unit volume （V） are all enlarged with the increases in Pr con- tent. According to the magnetic measurements, as the Pr content increases to larger than 0.4, both the Curie tem- perature （Tc） and the anisotropy field （HA） of all the Pr- doped compounds decrease rapidly. Meanwhile, the mag- netization of Sml_xPr.Co5 compounds at applied field of 14 T （MI4 T） are observably improved with Pr doping content of x 〉 0.3. Among them, Smo.6Pro.4Co5 compound exhibits slightly lower HA and Tc, but much higher M14 T than those of the binary SmCos, indicating that doping of proper Pr content into SmCo5 compound can optimize the intrinsic magnetic properties. As a result, the optimal intrinsic magnetic properties of HA = 29.11 T,Tc = 989 K, and M14 T = 102.31 mA.m2.g-1 are obtained in Smo.6Pro.4C05 compound.