连续椎旁神经阻滞对食管癌根治术中血流动力与术后镇痛效果和炎性因子水平的影响

目的观察连续椎旁神经阻滞应用于食管癌根治术对患者术中血流动力学与术后镇痛效果和炎性因子水平的影响。方法将80例食管癌根治术患者按照随机数字表法平均分为两组,对照组行气管内插管全身麻醉,观察组采取全身麻醉联合连续椎旁神经阻滞。比较两组术中血流动力学指标如平均动脉压(MAP)、心率(HR)、手术不同时刻[诱导前(T0)、插管即刻(T1)、切皮时(T2)、术中1h(T3)、手术结束即刻(T4)、拔管即刻(T5)]炎性因子水平、术后疼痛情况。结果观察组T2、T3、T4时刻MAP及HR水平均低于对照组,对照组T1、T2、T3、T4时刻MAP及HR水平均高于T0时刻(P0.05);观察组手术结束即刻、术后12 h、术后24 h及术后48 h白细胞介素-6、白细胞介素-8及肿瘤坏死因子α水平均低于对照组(均P0.05);观察组手术结束即刻、术后6 h、术后12 h、术后24 h、术后48 h视觉模拟评分均低于对照组(P0.05);两组不良反应比较,差异无统计学意义(P0.05)。结论连续椎旁神经阻滞应用于食管癌根治术血流动力学稳定,且降低机体炎性因子水平,术后疼痛程度低。     

High-strength lignin-based carbon fibers via a low-energy method

Bio-renewable carbon fibers are fabricated and employed as high-strength composite materials in many fields. In this work, a facile and low energy consumption method was developed to fabricate high-strength lignin-based carbon fibers. Using iodine treatment, the thermodynamic stability of the lignin-based precursor fibers increased significantly, and thus energy consumption during the preparation of the carbon fibers was reduced. The influence of the iodine treatment on fibers was analyzed by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Raman spectroscopy, tension testing, etc. The resulting iodine lignin-based carbon fibers had better tensile strength (89 MPa) than that of PAN carbon fibers produced by electrospinning technology.

A simple low-energy method to fabricate lignin-based carbon fibers with excellent mechanical properties via electrostatic spinning.     

Highly sensitive p-type 4H-SiC van der Pauw sensor

This paper presents for the first time a p-type 4H silicon carbide (4H-SiC) van der Pauw strain sensor by utilizing the strain induced effect in four-terminal devices. The sensor was fabricated from a 4H-SiC (0001) wafer, using a 1 μm thick p-type epilayer with a concentration of 10¹⁸ cm⁻³. Taking advantage of the four-terminal configuration, the sensor can eliminate the need for resistance-to-voltage conversion which is typically required for two-terminal devices. The van der Pauw sensor also exhibits an excellent repeatability and linearity with a significantly large output voltage in induced strain ranging from 0 to 334 ppm. Various sensors aligned in different orientations were measured and a high sensitivity of 26.3 ppm⁻¹ was obtained. Combining these performances with the excellent mechanical strength, electrical conductivity, thermal stability, and chemical inertness of 4H-SiC, the proposed sensor is promising for strain monitoring in harsh environments.

This paper presents for the first time a p-type 4H silicon carbide (4H-SiC) van der Pauw strain sensor by utilizing the strain induced effect in four-terminal devices.     

N-Acetyl-l-leucine-polyethylenimine-mediated miR-34a delivery improves osteogenesis and bone formation in vitro and in vivo

Oral bone defects are difficult to treat. Recently, endogenous miR-34a was shown to be involved in bone anabolism. Clinical application of such microRNAs requires the inherent instability of microRNAs to be overcome by an efficient delivery system. In this study, we employed N-acetyl-l-leucine-modified polyethylenimine (N-Ac-l-Leu-PEI) as an miR-34a carrier and evaluated its delivery ability, transfection efficiency, cytotoxicity and whether it enhanced osteogenic differentiation and bone formation in vitro and in vivo. Stable N-Ac-l-Leu-PEI/miR-34a nanocomplexes were synthesized at a mass ratio of 4 and had a small size (190.34 nm), a low zeta potential (21.1 mV), a high transfection efficiency (69.39%) and no cytotoxicity in MG63 cells. N-Ac-l-Leu-PEI-mediated miR-34a delivery in vitro promoted ALP activity and expression of osteogenic differentiation markers, Runx2, SP7 and ColI to higher levels than those produced by Lipofectamine 2000-mediated delivery. N-Ac-l-Leu-PEI also achieved delivery of miR-34a in vivo to a local cranial bone defect area with miR-34a retaining the ability to initiate significant new bone formation 12 weeks post-implantation. This demonstrates the potential for N-Ac-l-Leu-PEI as a gene therapy vehicle for the regeneration of bone defects.

We employ N-acetyl-l-leucine-modified polyethylenimine as an miR-34a carrier and evaluate its delivery ability, transfection efficiency, cytotoxicity and whether it enhances osteogenic differentiation and bone formation in vitro and in vivo.     

Electrolytic extraction of dysprosium and thermodynamic evaluation of Cu–Dy intermetallic compound in eutectic LiCl–KCl

The electrochemical reduction of dysprosium(iii) was studied on W and Cu electrodes in eutectic LiCl–KCl by transient electrochemical methods. Cyclic voltammogram and current reversal chronopotentiogram results demonstrated that dysprosium(iii) was directly reduced to dysprosium (0) on the W electrode through a single-step process with the transfer of three electrons. Electrochemical measurements on the Cu electrode showed that different Cu–Dy intermetallics are formed. Moreover, the thermodynamic properties of Cu–Dy intermetallic compounds were estimated by open circuit chronopotentiometry in a temperature range of 773–863 K. Using the linear polarization method, the exchange current density (j₀) of dysprosium in eutectic LiCl–KCl on the Cu electrode was estimated, and the temperature dependence of j₀ was studied to estimate the activation energies associated with Dy(iii)/Cu₅Dy and Dy(iii)/Cu_9/2Dy couples. In addition, potentiostatic electrolysis was conducted to extract dysprosium on the Cu electrode, and five Cu–Dy intermetallic compounds, CuDy, Cu₂Dy, Cu_9/2Dy, Cu₅Dy and Cu_0.99Dy_0.01 were identified by X-ray diffraction, scanning electron microscopy and energy dispersive spectrometry. Meanwhile, the change of dysprosium(iii) concentration was monitored using inductively coupled plasma-atomic emission spectrometry, and the maximum extraction efficiency of dysprosium was found to reach 99.2%.

The electrochemical reduction of dysprosium(iii) was studied on W and Cu electrodes in eutectic LiCl–KCl by transient electrochemical methods.     

Highly stretchable,mechanically stable,and weavable reduced graphene oxide yarn with high NO2 sensitivity for wearable gas sensors

Stretchable gas sensors are important components of wearable electronic devices used for human safety and healthcare applications. However, the current low stretchability and poor stability of the materials limit their use. Here, we report a highly stretchable, stable, and sensitive NO₂ gas sensor composed of reduced graphene oxide (RGO) sheets and highly elastic commercial yarns. To achieve high stretchability and good stability, the RGO sensors were fabricated using a pre-strain strategy (strain-release assembly). The fabricated stretchable RGO gas sensors showed high NO₂ sensitivity (55% at 5.0 ppm) under 200% strain and outstanding mechanical stability (even up to 5000 cycles at 400% applied strain), making them ideal for wearable electronic applications. In addition, our elastic graphene gas sensors can also be woven into fabrics and clothes for the creation of smart textiles. Finally, we successfully fabricated wearable gas-sensing wrist-bands from superelastic graphene yarns and stretchable knits to demonstrate a wearable electronic device.

Highly stretchable, mechanically stable and weavable RGO elastic electronic yarns were developed using dip-coating with pre-straining. We demonstrate wearable gas sensors that can be worn on the wrist.     

Detection of cofilin mRNA by hybridization-sensitive double-stranded fluorescent probes

We have developed hybridization-sensitive fluorescent oligonucleotide probes that, in the presence of quencher strands, undergo efficient fluorescence quenching through the formation of partial DNA/DNA duplexes. In the presence of target RNA, rapid displacement of the quencher strands results in highly enhanced fluorescence.

We have developed hybridization-sensitive fluorescent oligonucleotide probes that, in the presence of quencher strands, undergo efficient fluorescence quenching through the formation of partial DNA/DNA duplexes.

The detection of biomolecules is an important part of any investigation into their biological mechanisms and phenomena. Fluorescence-based methods are particularly useful for providing interpretable signals for various targets (e.g., genes, proteins, small molecules). When nucleic acids are used as probes, they can provide sequence-specific information regarding the binding (through hydrogen bonding) of target nucleic acids. Because of their high sequence-specificity, many fluorescent hybridization probes, including molecular beacons (MBs), have been developed and applied for nucleic acid detection and visualization.^1,2In previous studies, we found that a quencher-free molecular beacon (QF-MB) containing the pyrene-modified nucleoside ^PyU exhibited a high fluorescence enhancement in the presence of trinucleotide repeats, especially for RNA.^3,4 Among various fluorescent nucleobase derivatives, uracil derivatives have been particularly useful for selective detection of specific sequences, taking advantage of changes in photoinduced electron transfer between the fluorophore and the neighboring base.^3–5 To apply such systems to various other target sequences, here we designed fully complementary sequences and incorporated the internal fluorescent nucleoside ^PyU in place of a thymine residue, resulting in a significantly increased fluorescence signal based on strand displacement (Fig. 1). Incorporation of a ^PyU unit in a single strand of the probe sequence and hybridization with a strand partially complementary to the probe strand containing a pyrene unit as a fluorescence quencher can lead to improved discrimination factors.^4,6 Such partially double-stranded probes have several attractive features.Open in a separate windowFig. 1(A) Schematic representation of the strand displacement process developed in this present system. (B) Structures of the internal fluorophore ^PyU.First, the probe sequence does not require an additional sequence in its strand that is not complementary to the target sequence to ensure formation of a secondary structure (e.g., a hairpin). Such additional sequences might interfere with the specific hybridization between the probe and the target sequence. Accordingly, double-stranded fluorescence probes should allow the specific detection of many kinds of targets. Second, the highly quenched initial fluorescence signal, due to the formation of a partial duplex, results in significantly increased fluorescence in the presence of the target; the incorporation of a hybridization-sensitive internal fluorophore provides a stable and sensitive fluorescence signal upon perfect hybridization with the target.Cofilin is a protein that regulates the activity of actin, which is related to the formation of the cytoskeleton in cells. Actin plays a crucial role in the growth and elongation of cells,⁷ especially in neurons and, therefore, in the control of neurotransmission. We designed probe strands complementary to the 3′-untranslated region (3′-UTR) of target cofilin mRNA and synthesized three kinds of 19-mer probe strands (P1–P3) containing one or two ^PyU units in each strand (Fig. 2A and S1, ESI^†). The fluorescence intensities of P1 and P3 increased dramatically after binding with the target RNA T19—by 17.6- and 16.0-fold, respectively. For the probe P2 (in which the ^PyU residue was located close to the 3′-end), however, the fluorescence enhancement was very low: only 1.8-fold (Table S2, ESI^†). We assume that terminal modification of the ^PyU unit in the probe resulted in weak base pairs around the ^PyU residue than did central modification, resulting in a decrease in fluorescence enhancement (Table S3, ESI^†).⁸ Because flanking base pairs around the ^PyU unit are relatively less rigid compared to central base pairs, the microenvironment of ^PyU in the duplex formed from P2 and T19 is different from the central modification. Therefore, the fluorescence intensity did not increase significantly compared to the single-stranded P2. The absorption spectrum of P2 in the presence of T19 exhibited a relatively less intense absorption band than that of the duplex formed from P1 and T19—the latter featured an intense signal corresponding to the high fluorescence intensity (Fig. S1, ESI^†).^9,10 Even though two ^PyU units were incorporated into the single strand P3, its fluorescence enhancement was similar to that of probe P1 containing only one ^PyU unit. Among other examined probe sequences complementary to other parts of 3′-UTR in cofilin mRNA, P6 (containing two ^PyU units) also exhibited fluorescence intensity similar to those of P4 and P5, single-^PyU – containing probes each modified in the central position (Fig. S2, ESI^†). These results suggest that single modification of a ^PyU unit in the probe sequence is more efficient than dual modification, in terms of inducing high fluorescence enhancement with target RNA.Oligonucleotide sequences of probe and target strands

Homogeneity and tolerance to heat of monolayer MoS2 on SiO2 and h-BN

We investigated the homogeneity and tolerance to heat of monolayer MoS₂ using photoluminescence (PL) spectroscopy. For MoS₂ on SiO₂, the PL spectra of the basal plane differ from those of the edge, but MoS₂ on hexagonal boron nitride (h-BN) was electron-depleted with a homogeneous PL spectra over the entire area. Annealing at 450 °C rendered MoS₂ on SiO₂ homogeneously electron-depleted over the entire area by creating numerous defects; moreover, annealing at 550 °C and subsequent laser irradiation on the MoS₂ monolayer caused a loss of its inherent crystal structure. On the other hand, monolayer MoS₂ on h-BN was preserved up to 550 °C with its PL spectra not much changed compared with MoS₂ on SiO₂. We performed an experiment to qualitatively compare the binding energies between various layers, and discuss the tolerance of monolayer MoS₂ to heat on the basis of interlayer/interfacial binding energy.

We investigated the homogeneity and tolerance to heat of monolayer MoS₂ using photoluminescence (PL) spectroscopy.     

Cobalt metal-mixed organic complex-based hybrid micromaterials: ratiometric detection of cyanide

A micrometer-sized hybrid crystalline material was facilely fabricated from the synergistic coordination chemistry of two types of 2-hydroxyazobenzene building blocks and cobalt ions. This hybrid crystalline material functioned as both receptor and signal reporter in cyanide (CN⁻) sensing with ratiometric absorption responses at 456 nm and 537 nm. The mechanism of CN⁻ sensing involves partial ligand dissociation accompanied by the formation of a new organic metal–CN⁻ adduct. We believe that this protocol would be valuable in achieving the expected selectivities and sensitivities for a wide variety of analytes in many chemical and biological systems in the future.

A cobalt metal-mixed organic complex-based hybrid micromaterial has been presented to detect CN⁻ with ratiometric absorption responses (A_{456 nm}/A_{537 nm}).