Influence of oscillating uniform magnetic field and iron supplementation on quality of freeze-thawed surimi

An oscillating uniform magnetic field was applied during the freezing of surimi. Samples were placed at the central zone of a pair of Helmholtz coils (acting as the freezing chamber, guaranteeing a 99% magnetic field homogeneity) during freeze-thawing. The magnetic field parameters were 4 mT and 50 Hz. After treatments, the physicochemical properties of the samples were immediately investigated. The magnetic field decreased the amount of thawing loss and strengthened the water-holding capacity of the surimi compared to the control. The denaturation temperature, denaturation enthalpy, and protein stability increased as the magnetic field was applied. The addition of ferrous ions (15 mg Fe per kg surimi, ferrous citrate) enhanced the molecular current under the field due to electromagnetic induction. Morphological observation of the surimi revealed that ferrous ions significantly influenced its structure after freeze-thawing, yielding the smallest pores among the sample groups. These findings indicate that the quality of freeze-thawed surimi product could be improved by using an oscillating uniform magnetic field combined with iron supplementation.

An oscillating uniform magnetic field was applied during the freezing of surimi.     

An In Vivo Rat Model of Artery Buckling for Studying Wall Remodeling

Theoretical modeling and in vitro experiments have demonstrated that arterial buckling is a possible mechanism for the development of artery tortuosity. However, there has been no report of whether artery buckling develops into tortuosity, partially due to the lack of in vivo models for long-term studies. The objective of this study was to establish an in vivo buckling model in rat carotid arteries for studying arterial wall remodeling after buckling. Rat left carotid arteries were transplanted to the right carotid arteries to generate buckling under in vivo pressure and were maintained for 1 week to examine wall remodeling and adaptation. Our results showed that a significant buckling was achieved in the carotid arterial grafts with altered wall stress. Cell proliferation and matrix metalloprotinease-2 (MMP-2) expression in the buckled arteries increased significantly compared with the controls. The tortuosity level of the grafts also slightly increased 1 week post-surgery, while there was no change in vessel dimensions, blood pressure, and blood flow velocity. The artery buckling model provides a useful tool for further study of the adaptation of arteries into tortuous shapes.     

Water-soluble lanthanide coordination polymers particles with white-light emission and color tuning

Water-soluble polymer particles (PPs) with strong fluorescence emission were prepared from hyperbranched poly(ethylenimine) (PEI) and terpyridine-bearing aldehyde (TPy) via Schiff base reaction and self-assembly in aqueous phase. TPy/PEI PPs were then used to develop a series of luminescent lanthanide coordination polymers particles (Ln-CPPs). The optical properties of these Ln-CPPs are readily modulated over a wide spectrum in water systems. Finally, water-soluble white-emitting Ln-CPPs were achieved by controlling the lanthanide ion stoichiometry. This Ln-CPPs design approach offers a robust pathway for white-luminescent materials in water systems.

Water-soluble polymer particles (PPs) with strong fluorescence emission were prepared from hyperbranched poly(ethylenimine) (PEI) and terpyridine-bearing aldehyde (TPy) via Schiff base reaction and self-assembly in aqueous phase.

In recent decades, dynamic metal coordination polymers (M-CPs) have attracted great interest in catalysis, drug delivery, chemical sensors and bioanalysis applications.^1–7 M-CPs are constructed from metal ions and organic ligands with a variety of structures and interesting properties for many potential applications. M-CPs acting as chemical sensors are mainly explored by making use of their luminescence properties.^8–10 The luminescent M-CPs can emit a stable and intense luminescent emission, so some substances can be detected by observing changes in luminescence intensity. It is well known that lanthanide ions have high color purity and long lifetime excitation lifetime, and the emission covers the entire visible range of 400 to 700 nm. In particular, Eu(iii) and Tb(iii) ions can emit intense red and green light, respectively. Lanthanide coordination polymers (Ln-CPs) are promising luminescent materials because lanthanide ions have similar chemical properties and two or more lanthanide ions can be randomly distributed in coordination polymers with metal sites, which can modulate the color and brightness of the emission.¹¹ For the above reasons, Ln-CPs have attracted the attention of many scientists and have been effectively used to design multiple color and white light emitting materials. For example, He and co-workers¹² developed a new fluorophore that exhibits white light by combining an Eu(iii) moiety (red emission) with an organic ligand (blue and green emission). Ma et al.¹³ reported a white-light-emitting La(iii)/Tb(iii)/Eu(iii) coordination polymers based on combination of blue-emitting ligand/La(iii), green-emitting Tb(iii) and red-emitting Eu(iii) units. Song et al.¹⁴ developed a white-light-emitting compound by doping a Eu(iii) ion into the Gd(iii) framework.Meanwhile, the selection of suitable ligands plays a crucial role in the synthesis of Ln-CPs with good luminescent properties, since organic ligands can be used not only as building blocks for the construction of new backbones of Ln-CPs, but also as effective sensitizer for Ln(iii) ions.^15,16 However, ligands are generally poorly water soluble, which limits the practical sensing application in environmental and biological systems.¹⁷ An efficient strategy to promote dispersion in water is to prepare Lanthanide coordination polymer particles (Ln-CPPs) by miniemulsion method, reprecipitation method, and so on.¹⁸ Nevertheless, several drawbacks still exist for their preparation and application, such as sophisticated multistep synthetic pathways, use of environmentally unfriendly organic solvents, and the possibility of fluorescence self-quenching in aqueous solution. Therefore, the systematic investigation of water-soluble Ln-CPPs with white-light emission is quite rare. More research studies are urgently needed to accelerate the development of white-light luminescent Ln-CPPs in the water system.Based on the above considerations, we rationally designed water-soluble polymer particles with blue emission and selected Tb(iii)/Eu(iii) to construct white-light-emitting Ln-CPPs (Fig. 1). The water-soluble polymer particles were constructed from hyperbranched poly(ethylenimine) (PEI) and terpyridine-bearing aldehyde (TPy) via Schiff base reaction and self-assembly. Structural characterization and luminescence properties in the water system of Ln-CPPs are studied in detail. An important clue could be obtained from the result that Ln-CPPs constructed by terpyridine ligands can maintain their structural and luminescent properties in the water system. This research also provides a basis for realizing the controllability of water-soluble white-light-emitting Ln-CPPs in the future.Open in a separate windowFig. 1Schematic preparation of TPy/PEI PPs and Ln(III) coordination-based luminescent polymer particles (Ln-CPPs) under UV light (λ_ex = 365 nm).Synthesis of the TPy/PEI PPs is based on facile Schiff base reaction, which refers to the reaction between primary amine on PEI and aldehyde group on TPy, resulting in a product containing C N bonds. Moreover, the diluted TPy/PEI PPs solution emits blue fluorescence under a 365 nm UV lamp. Fig. 2A displays the fluorescence excitation and emission spectra of the TPy/PEI PPs solution, and the maximum excitation and emission wavelengths are 330 and 448 nm, respectively. The UV-vis absorption spectra of TPy/PEI PPs, PEI and TPy were shown in Fig. S4.^† Compared with TPy, the absorption peak at 250 nm in TPy/PEI PPs solution is weakened, which may be due to the decolorization effect caused by the formation of copolymer by TPy and PEI. In addition, the absorption peak at 335 nm in TPy/PEI PPs solution is attributed to n → π* transitions of C N bonds.^18,19 These phenomena indicated TPy/PEI PPs were a newly generated subject.Open in a separate windowFig. 2(A) Fluorescence excitation and emission spectra of TPy/PEI PPs (0.01 g mL⁻¹). (Inset) Photographs of TPy/PEI PPs under visible light and UV light of 365 nm. (B) FT-IR spectra of TPy/PEI, PEI, and TPy.The morphologies of TPy/PEI PPs were characterized by transmission electron microscopy (TEM), Fig. S5A^† is a TEM image and reveals that the TPy/PEI PPs are monodisperse spherical shape with the size distribution in the range of 26–50 nm. Formation of water-soluble nanoparticles is due to the following factors. In TPy/PEI copolymer, ample amine groups and pyridinium groups are hydrophilic, whereas Schiff base bonds are hydrophobic. As a result, the hyperbranched structure of TPy/PEI copolymer tends to fold and collapse, shrinking and self-assembling into uniform polymer nanoparticles in aqueous medium.¹⁸ Many hydrophilic groups on the surface of TPy/PEI PPs make the excellent water dispersity possible. To further explore the chemical composition of TPy/PEI PPs, we performed FT-IR spectra of PEI, TPy, and TPy/PEI PPs (Fig. 2B). Several featured vibration bands at 3284 and 1590 cm⁻¹ in PEI are associated with the stretching vibration of N–H bond, and their intensity is decreased in TPy/PEI PPs, which indicates that some amine groups have reacted with TPy. In addition, another remarkable new peak at 1630 cm⁻¹ was observed in TPy/PEI PPs, which can be assigned to the C N bond.^20–25 Meanwhile, a new peak at 8.37 ppm was observed in the ¹H NMR spectra of TPy/PEI PPs (Fig. S6^†), which can be assigned to N CH protons.²⁶ The monitoring of the aldehyde conversion into imine units can be carried out by measuring the CH̲O/CH̲ N integral ratio, and the conversion rate of the aldehyde into imine units is 69%. The estimation of the conversion rate from the ¹H-NMR spectrum agrees well with the calculation from the weighting measurements with a conversion rate of 73%. These analysis results well demonstrated the formation of Schiff base bonds between TPy and PEI.TPy/PEI PPs possess intrinsic fluorescence, good water solubility, and functional terpyridine structure unit, allowing us to incorporate the Ln(iii)-TPy coordination complexes into polymer networks. With the incremental addition of Tb(NO₃)₃ to the TPy/PEI PPs solution (2% v/v), the TPy : Ln ratio is 2 : 1, which produces green-luminescent Ln-CPPs, GL CPPs (τ = 0.35 ms, Φ = 4.3%, CIE coordinates (0.27, 0.36), Fig. S7, S8 and Table S1^†). In the corresponding emission spectrum, a decrease in the luminescence intensity of the ligand centred emission band at 448 nm with the concomitant emergence of sharp bands at 489 nm, 544 nm, 583 nm, and 622 nm was observed (Fig. S7^†). A decrease in the luminescence intensity of the central emission band of the ligand was observed. These emission bands were assigned to ⁵D₄–⁷F₆, ⁵D₄–⁷F₅, ⁵D₄–⁷F₄, and ⁵D₄–⁷F₃ based transitions, respectively, for Tb(iii).^27–30 A similar procedure was observed upon addition of Eu(NO₃)₃ to the TPy/PEI PPs solution with the occurrence of five characteristic Eu(iii)-based emission bands having maxima at 579 nm (⁵D₀–⁷F₀), 592 nm (⁵D₀–⁷F₁), 617 nm (⁵D₀–⁷F₂), 649 nm (⁵D₀–⁷F₃), and 687 nm (⁵D₀–⁷F₄), resulting in a clear red-luminescent Ln-CPPs, RL CPPs (τ = 0.81 ms, Φ = 11.3%, CIE coordinates (0.52, 0.29)). These emission spectra demonstrate that Ln³⁺ (Eu³⁺ or Tb³⁺) ions were successfully doped to the TPy/PEI PPs. More importantly, strong fluorescence could still be detected even after these Ln-CPPs were stored for over a week, implying that the coordination between the TPy/PEI PPs and Ln³⁺ ions is very stable. The interactions between the TPy/PEI PPs and Ln³⁺ ions were further monitored by FT-IR spectroscopy (Fig. S9^†). Strong absorbent bands at 3256, 1549 and 1398 cm⁻¹ in TPy/PEI PPs are attributed to the stretching vibrations of N–H bond.^18,19 After the formation of RL CPPs, GL CPPs or WL CPPs using Ln³⁺ ions, a dramatically red shift appeared, which indicated the coordination of the TPy/PEI PPs to Ln³⁺ ions. The medium-to-weak bands at 760 cm⁻¹ for RL CPPs, 769 cm⁻¹ for GL CPPs and 765 cm⁻¹ for WL CPPs are observed as additional evidence of the Ln–N formation.³¹Next we investigated how to modulate the emission of polymer particles by adjusting the stoichiometry of the two lanthanide chromophores. Titration of the Tb/Eu molar ratio resulted in a series of Ln-CPPs with a broad spectrum of emission under UV irradiation (Fig. 3A). By testing the emission spectrum (Fig. 3B and C), it was found that the intensity of the green band at 544 nm increased gradually at the expense of the intensity of the red band at 616 nm as a function of Tb/Eu molar ratio. Interestingly, an intense white-luminescent Ln-CPPs, WL CPPs (CIE coordinates (0.33, 0.34)), were observed when the Eu/Tb molar ratio was 1 : 4. The smart illumination control strategy here provides a simple design approach for broad-spectrum color adjustment of luminescent polymer materials.Open in a separate windowFig. 3Luminescence tuning: (A) photographs of Ln-CPPs under UV irradiation, corresponding CIE coordinates are mentioned below; (B) emission spectra (λ_ex = 330 nm) of Ln-CPPs and (C) Job''s plot showing the peak emission intensity of the red band at 544 nm and green band at 616 nm as a function of the Tb/Eu molar ratio (1 : 1, 2 : 1, 3 : 1, 4 : 1, 5 : 1, 6 : 1, 7 : 1, and 8 : 1).In conclusion, we created polymer particles with blue emission from PEI and TPy via Schiff base reaction and self-assembly under mild conditions. The structural characterization and the fundamental properties of the TPy/PEI PPs have been studied. Because of the specific structure, the TPy/PEI PPs exhibit excellent water solubility. Furthermore, we have used the TPy/PEI PPs to develop a series of luminescent Ln-CPPs with Eu(iii), Tb(iii), and mixed Eu(iii)/Tb(iii) in aqueous medium. The individual Ln-CPPs exhibited bright red (Eu-CPPs) and green (Tb-CPPs) fluorescence upon exposure to UV light (λ_ex = 365 nm). Careful tuning of the stoichiometric ratio of Eu(iii) and Tb(iii) helped in achieving water-soluble white-emitting Ln-CPPs, which could offer a suitable pathway for preparing white-luminescent materials in water systems. Due to their stability in water, in our next work efforts will be focused on exploring their potential applications in biological and environmental areas as luminescence sensing and quantitative detection materials.     

Spacer layer design for efficient fully printable mesoscopic perovskite solar cells

The spacer layer is a key component of fully printable mesoscopic perovskite solar cells, but its precise characteristics are far from being understood in relation to the device design. In the present work, we perform a detailed systematic study on the effects of spacer parameters, such as size of building blocks, layer thickness, etc., on properties of the perovskite filler, insulating ability and performance of fully printable mesoscopic perovskite solar cells by combining the techniques of time-resolved photoluminescence, high-resolution TEM, insulating resistance measurements, impedance spectroscopy and J–V characteristics. Drawing on the deep understanding from these studies, we formulate key principles, which are anticipated to guide the design of the advanced spacer layer for fully printable mesoscopic perovskite solar cells.

Key principles and reasonable routes are proposed to advance the spacer layer design for fully printable mesoscopic perovskite solar cells.

Lead halide perovskite (PVSK) as a promising semiconducting material has been introduced as a light harvesting semiconductor because of its ease of fabrication and excellent physical properties, such as tunable bandgap, strong absorbance, long carrier diffusion length and shallow intrinsic trap state level.^1–9 Extremely flat and compact perovskite thin film with large crystal size has gained particular attention to boost power conversion efficiency (PCE) by sequential deposition method, vapor deposition, solvent-annealing, solvent engineering, hot-casting method, intramolecular exchange methods, and additive, etc.^10–16 Benefiting from rapid improvements in formation of high quality perovskite thin film, a certified PCE of 25.2% has been achieved.¹⁷ However, illumination stability in real environment still remains a serious challenge due to the inherent moisture and UV sensitivity of perovskite. Moreover, using expensive and rare metals as back contact, such as gold and silver, may limit large-scale production in the future. As the competing architecture of perovskite solar cells, TiO₂/spacer/carbon (abbreviated as TSC) films based fully printable mesoscopic perovskite solar cells (FP-MPSC) have attracted a lot of researchers due to their low cost and printable large-scale production process.^18–21 In this type of solar cell, carbon can efficiently collect hole from perovskite layer even without any other hole transporting materials.^22,23 Most importantly, FP-MPSC could work with excellent illumination stability and heat-stress stability by filling TSC films with (5-AVA)_xMA_1−xPbI₃ (5-AVA = 5-aminovaleric acid, MA = methylammonium), although the efficiency of 12.8% is still far behind from the most efficient solar cell.^16,21,24Spacer, as an important part of FP-MPSC, plays a crucial role in obtaining high performance device. Basically, the spacer layer mainly burdens triple important tasks in the efficient mesoscopic perovskite solar cells. Firstly, the core function of spacer is to separate anode and cathode and to prevent electrons in TiO₂ from transporting directly to carbon electrode. The separating property of spacer depends on spacer particle sizes, morphology, materials, etc. This requires that spacer layer has no cracking and has wide bandgap. Secondly, the perovskite confined in the mesopores of spacer layer can absorb photons transmitted through perovskite/TiO₂ composite layer and have contribution to photocurrents. Thirdly, the holes produced in the perovskite/TiO₂ composite layer have to go through perovskite/spacer composite layer to reach carbon electrode. And the electrons produced in the perovskite/spacer composite layer have to go through perovskite/spacer composite layer to reach TiO₂ electrode. Because spacer layer has these important functions, some research on spacer layer have been carried out. Recently, Al₂O₃ or ZrO₂ spacer layer was compared with respect to their pore size.²⁵ However, conclusion of the effect of pore size in two different materials was incomplete. The effect of spacer layer thickness was simply discussed both in monolithic dye-sensitized solar cells and FP-MPSC.^20,26 The morphology of spacer layer was also improved to increase PCE of FP-MPSC.²⁷ Although these researches made some progress, there are no clear standards that what should an ideal spacer layer satisfy. Therefore, it is urgent to carry out detailed study on how the parameters of spacer affect the above functions and performance of mesoscopic printable perovskite solar cells.In the present study, the effects of size of building blocks of spacer layer, thickness of spacer layer on property of perovskite crystals, insulating property, and performance of mesoscopic perovskite solar cells were investigated in details. Based on these deep understandings, critical principles to design advanced spacer layer are proposed.ZrO₂ is used as spacer material due to its large band gap and high conduction band energy level. There are five different sizes of spacer building blocks in this study. The average particle sizes of spacer are measured to be about 5 nm, 10 nm, 20 nm, 60 nm and 100 nm, respectively, and hereafter referred to as S5, S10, S20, S60, S100 spacer, respectively. SEM images of as-prepared spacer films using these building blocks are shown in Fig. 1. X-ray diffraction patterns of spacer film with different particle sizes are presented in Fig. 1f, indicating that the five spacer films were all tetragonal crystal phase as majority phase. From Scherrer equation, the crystal sizes of spacer building blocks were calculated to be about 5 nm, 10 nm, 20 nm, 30 nm, 30 nm, respectively. These results indicated that the S60 and S100 particles are consisted of 30 nm sized crystal ZrO₂. Fig. 1 presents that there is a large difference in surface morphology with particle size increasing. There are cracks in S5 and S10 spacer films and micrometer scale pores exist in the S100 spacer, while the surface of S20 and S60 are very uniform without defects.Open in a separate windowFig. 1SEM images of spacer films with particle size of 5 nm (a), 10 nm (b), 20 nm (c), 60 nm (d) and 100 nm (e), respectively. (f) XRD patterns of spacer film with different building block sizes.During solvent evaporation of perovskite precursor, perovskite crystal growth is restricted by randomly interconnected mesopores of spacer film, leading to nanoscale crystal size and random crystal orientation, as observed by high resolution transmission electron microscope (Fig. 2a), in which clear crystal lattices of perovskite crystals can be distinguished from spacer particles. Meanwhile, the mesopores of spacer film is fulfilled with perovskite materials, providing continuous channels for charge carriers. The crystal size of perovskite material in spacer film is strongly influenced by mesopore size of spacer layer, as seen in XRD intensity of perovskite at 2θ of about 14.2° (Fig. 2b). There is an apparent trend that the intensity increased with increasing the particle size of spacer film. As a reference, perovskite was also deposited on bare glass, which exhibited the best crystallinity. The calculated sizes of perovskite from XRD spectra are 4.3 nm, 3.9 nm, 6.2 nm, 11.5 nm, and 12.6 nm, respectively, for the S5, S10, S20, S60, and S100 spacer layer. Apparently, the sizes of perovskite crystals confined in the spacer layer are smaller than the average pore sizes of spacer layer measured by N₂ absorption/desorption isotherms (Table S1^†). The high-resolution TEM image also gives consistent results. For example, the sizes of perovskite crystals confined in the S20 spacer layer are between 8.4 nm to 12.7 nm measured in the TEM image (Fig. 2a). The infiltrated perovskite started to nucleate onto the heterogeneous surface of spacer building blocks with high surface area, resulting to multiple nucleation centers and small crystal size. In order to evaluate the effect of spacer particle size on physiochemical properties of perovskite, the band-edge emission spectra of perovskite/spacer composite film were measured in Fig. 2c. The band-edge emission spectrum of perovskite deposited on bare glass peaked at 762 nm (with photon energy of 1.627 eV). As the particle size of spacer film decreased, a blue shift of the band-edge photoluminescence occurred, and linewidth broadened. The peak position of perovskite emission spectra can be tuned in the range of 33 nm through varying the pore size of spacer film. The increase of emission line width at grain boundaries can be attributed to disorder and defects of perovskite,^14,15 which also led to the decrease of lifetime in time-resolved PL (Fig. 2d). Perovskite film grown on glass has the lifetime of 141.9 ns. However, perovskite grown in spacer film decreased to 0.5 ns, 8.4 ns, 24.1 ns, 37.2 ns, 53.7 ns, for S5, S10, S20, S60, S100, respectively.Open in a separate windowFig. 2(a) High resolution transmission electron microscope image of perovskite/S20 spacer film composite. (b) XRD of perovskite/spacer film composite. (c) Steady PL emission spectra and (d) time-resolved PL of perovskite/spacer film composite.The particle size of spacer also has large effect on insulating ability of spacer films with the same thickness. FTO/spacer/carbon configuration was designed to measure the insulating ability of spacer layers. In ideal conditions, the resistance between carbon and FTO, defined as insulating resistance (R_I), should be infinite, indicating that there is not any leakage current from ideal insulating spacer. However, all of the measured resistance has finite values, summarized in 28–31Photovoltaic parameters of mesoscopic perovskite solar cells based on spacer with different building block sizes

One-step synthesis of red-emitting carbon dots via a solvothermal method and its application in the detection of methylene blue

The synthesis of carbon dots (CDs) with long wavelengths, particularly the red-emitting ones, has always been the focus of researchers, and a carbon source is critical in this process. In this study, we report the synthesis of red-emitting CDs (CD-tetra) via a one-step solvothermal method with 1,2,4,5-benzenetetramine tetrahydrochloride as a novel carbon source and ethanol as a solvent, and the quantum yield (QY) of CDs is as high as 30.2%. Middle chromatography isolated gel (MCI Gel) column was used to obtain R-CDs, O-CDs and Y-CDs with emission wavelengths at 619, 608 and 554 nm, respectively. It was discovered that these CDs exhibited great differences in their particle sizes and elemental compositions. Moreover, the fluorescence of the CD-tetra could be efficiently quenched using methylene blue (MB). Under optimal conditions, a linear relationship between the decreased fluorescence intensity of the CD-tetra and the concentration of MB was established in the range of 0.05–9.5 μM. The limit of detection (LOD) is 10 nM, suggesting a promising assay for the detection of MB.

Red-emitting CDs was synthesized via a one-step solvothermal method with 1,2,4,5-benzenetetramine tetrahydrochloride as a novel carbon source and ethanol as a solvent. The luminescence mechanism of CDs was studied by MCI gel column chromatography.     

Analysis on Bilateral Hindlimb Mapping in Motor Cortex of the Rat by an Intracortical Microstimulation Method

Intracortical microstimulation (ICMS) is a technique that was developed to derive movement representation of the motor cortex. Although rats are now commonly used in motor mapping studies, the precise characteristics of rat motor map, including symmetry and consistency across animals, and the possibility of repeated stimulation have not yet been established. We performed bilateral hindlimb mapping of motor cortex in six Sprague-Dawley rats using ICMS. ICMS was applied to the left and the right cerebral hemisphere at 0.3 mm intervals vertically and horizontally from the bregma, and any movement of the hindlimbs was noted. The majority (80%±11%) of responses were not restricted to a single joint, which occurred simultaneously at two or three hindlimb joints. The size and shape of hindlimb motor cortex was variable among rats, but existed on the convex side of the cerebral hemisphere in all rats. The results did not show symmetry according to specific joints in each rats. Conclusively, the hindlimb representation in the rat motor cortex was conveniently mapped using ICMS, but the characteristics and inter-individual variability suggest that precise individual mapping is needed to clarify motor distribution in rats.

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Pertussis Seroprevalence in Korean Adolescents and Adults Using Anti-Pertussis Toxin Immunoglobulin G

This study was conducted to evaluate age-specific seroprevalence of pertussis in Korea and to formulate a strategy to prevent and reduce the incidence of pertussis. Residual serum samples of healthy adolescents and adults 11 yr of age or older were collected between July 2012 and December 2012, and anti-pertussis toxin (PT) IgG titers were measured using a commercial ELISA kit. We compared the mean anti-PT IgG titers and seroprevalence of pertussis of the six age groups: 11-20, 21-30, 31-40, 41-50, 51-60, and ≥ 61 yr. A total of 1,192 subjects were enrolled. The mean anti-PT IgG titer and pertussis seroprevalence were 35.53 ± 62.91 EU/mL and 41.4%, respectively. The mean anti-PT IgG titers and seroprevalence were not significantly different between the age groups. However, the seroprevalence in individuals 51 yr of age or older was significantly higher than in individuals younger than 51 yr (46.5% vs 39.1%, P = 0.017). Based on these results, a new pertussis prevention strategy is necessary for older adults.

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Validity of the Korean Version of the Fear of Alzheimer's Disease Scale for the Assessment of Anticipatory Dementia

Anticipatory dementia is related to anxiety, which is a clinical predictor of early conversion to Alzheimer''s disease. The Fear of Alzheimer''s Disease Scale (FADS) is a reliable and valid instrument to address anticipatory dementia. The aim of the present investigation was to develop the Korean version of the Fear of Alzheimer''s Disease Scale (K-FADS) and to verify its reliability and validity. We developed the K-FADS to consist of 30 items with total scores ranging from 0 to 120, as in the original FADS. One hundred eight healthy volunteer participants, drawn from 3 different university hospitals, were evaluated. The K-FADS revealed good reliability (Cronbach α=0.96) and good validity as compared to the Korean version of the State-Trait Anxiety Inventory Form (r=0.242, P=0.013). Test-retest reliability was excellent, as the intra-class correlation coefficient comparing the retest to test was 0.98 (95% confidence interval, 0.96-0.99). Our results show that the K-FADS is a suitable and valuable scale to assess anticipatory dementia in elderly Koreans.

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Does Intravenous Ketamine Enhance Analgesia after Arthroscopic Shoulder Surgery with Ultrasound Guided Single-Injection Interscalene Block?: A Randomized,Prospective, Double-Blind Trial

Ketamine has anti-inflammatory, analgesic and antihyperalgesic effect and prevents pain associated with wind-up. We investigated whether low doses of ketamine infusion during general anesthesia combined with single-shot interscalene nerve block (SSISB) would potentiate analgesic effect of SSISB. Forty adult patients scheduled for elective arthroscopic shoulder surgery were enrolled and randomized to either the control group or the ketamine group. All patients underwent SSISB and followed by general anesthesia. During an operation, intravenous ketamine was infused to the patients of ketamine group continuously. In control group, patients received normal saline in volumes equivalent to ketamine infusions. Pain score by numeric rating scale was similar between groups at 1, 6, 12, 24, 36, and 48 hr following surgery, which was maintained lower than 3 in both groups. The time to first analgesic request after admission on post-anesthesia care unit was also not significantly different between groups. Intraoperative low dose ketamine did not decrease acute postoperative pain after arthroscopic shoulder surgery with a preincisional ultrasound guided SSISB. The preventive analgesic effect of ketamine could be mitigated by SSISB, which remains one of the most effective methods of pain relief after arthroscopic shoulder surgery.

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