不同剂量右美托咪定辅助硬膜外麻醉对老年直肠癌患者术后认知功能的影响

目的 观察不同剂量右美托咪定辅助硬模外麻醉对老年直肠癌开腹手术患者术后认知功能的影响.方法 选择60例70岁以上直肠癌手术患者,应用右美托咪定诱导剂量0.8 μg/（kg·min）泵注10 min,按维持剂量完全随机分为右美托咪定Ⅰ组0.4 μg/（kg·h）、Ⅱ组0.6 μg/（kg·h）、Ⅲ组0.8 μg/（kg·h）,每组20例.观察并记录3组患者入室时（T0）、用药后10 min（T1）、用药后20 min（T2）、停药即刻（T3）、停药后10 min（T4）以及手术完毕时（T5）的平均动脉压（MAP）、心率、脑电双频指数（BIS）以及镇静评分（Ramsay评分）.比较术前1 d、术后即刻、术后24 h 3组患者血浆中白细胞介素6（IL-6）、肿瘤坏死因子α（TNF-α）水平,比较3组患者术前1 d、术后1、3、7 d的简易智力状况检查法评分（MMSE）.结果 3组患者在T0时血压、心率、BIS值,镇静评分（Rammsy评分）差异均无统计学意义（P〉0.05）,T2、T3时MAP和HR均较基础值显著降低.随着右美托咪定的用量的增大,窦性心动过缓的发生率也增加,与Ⅰ、Ⅱ组相比,Ⅲ组患者T3时心率明显下降,差异有统计学意义[（54.8±6.8） 次/min 比（70.2±2.5）、（69.7±2.4） 次/min]（P〈0.05）.Ⅱ、Ⅲ组患者术中BIS值维持在60～75之间,可以满足术中的镇静要求.Ⅲ组患者术中BIS值下降,Ⅰ组共有8例出现术后认知功能障碍（POCD）,发生率为40.0%,Ⅱ组有2例出现POCD,发生率为10.0%,Ⅲ组共有5例出现POCD,发生率25.0%.Ⅰ组与Ⅱ组比较,其差异有统计学意义（χ2=4.5,P〈0.05）.与I组相比,术后即刻、术后24 hⅡ、Ⅲ组IL-6、TNF-α水平差异有统计学意义[术后即刻IL-6（3.6±0.4）、（3.6±0.4）ng/L比（5.7±0.4）ng/L,TNF-α（6.2±0.4）、（6.1±0.5）ng/L比（7.1±0.4）ng/L;术后24 h IL-6（3.4±0.4）、（3.4±0.4）ng/L比（6.8±0.4）ng/L,TNF-α（6.±0.5）、（6.1±0.5）ng/L比（7.1±0.4）ng/L]（P〈0.05）.结论 老年患者以0.8 μg/kg的剂量泵注右美托咪定10 min,后以0.6 μg/（kg·h）右美托咪定泵注复合硬膜外麻醉安全有效,可改善老年直肠癌患者围术期认知功能.     

Prompt surgery is effective for acute type A aortic dissection with cerebral ischemia

BackgroundAcute type A aortic dissection (aTAAD) with preoperative cerebral ischemia (CI) is common and lethal, but the timing and treatment method remain uncertain. We retrospectively reviewed our aTAAD patients with CI and analyzed the outcomes and related risk factors.MethodsFrom January 2011 to December 2019, 1,173 patients diagnosed with aTAAD from Nanjing Drum Tower Hospital were enrolled. Among them, 131 patients had CI preoperatively (CI group), and 1,042 patients were in the non-CI group. One hundred eight in the CI group and 984 in the non-CI group received central repair surgery. Fifteen patients had postoperative cerebral complications (CC) and 93 had non-CCs. ROC curves were used to identify the safe duration of preoperative CI.ResultsThe CI group was older (56.3 vs. 53.2 years, P=0.013) and had lower rates of pain, chest pain and back pain (77.9% vs. 94.4%, 75.4% vs. 87.5% and 30.8% vs. 42.3%, respectively) than the non-CI group. The CI group had a higher rate of preoperative hypotension and tamponade (13.7% vs. 6.0%, 26.9% vs. 10.4%, respectively; P=0.000). More patients in the CI group did not receive central repair surgery, and the CI had higher mortality (28.2% vs. 15.9%). CI without central repair surgery was a strong risk factor for mortality. CI patients with CC after central repair had a higher mortality, and preoperative coma was the strongest risk factor for postoperative CC.A duration between CI symptoms and central repair surgery of less than 12.75 hours is recommended.ConclusionsPrompt surgery is effective for aTAAD with CI, and preoperative coma and a safe duration longer than 12.75 hours would predict worse outcomes.     

Controlled hydrothermal temperature provides tunable permittivity and an improved electromagnetic absorption performance of reduced graphene oxide

Reduced graphene oxide (RGO) has been prepared by a hydrothermal reduction method to explore the effects of reaction temperature on its permittivity and electromagnetic absorption (EA) performance. This study shows that by controlling the oxygen functional groups on the RGO surface it is also possible to obtain an ideal EA performance without any other decorated nanomaterials.

Reduced graphene oxide (RGO) has been prepared by a hydrothermal reduction method to explore the effects of reaction temperature on its permittivity and electromagnetic absorption (EA) performance.

Electromagnetic fields play a critical role in modern electronic and communications industries. However, they also cause humans and wildlife to become chronically exposed to excessive electromagnetic radiation in the environment. Electromagnetic absorption (EA) is one of the most effective methods of managing electromagnetic pollution. Due to the mechanism, EA performance mainly depends on the permittivity and permeability of a material.¹ Thus, dielectric and magnetic materials and their hybrids have been considered as fillers to fabricate polymer based composites with EA performance properties.^2,3 Due to their large aspect ratios and fascinating dielectric properties, two-dimensional (2D) nanomaterials show huge potential for the application of EA.^1,4–8 Among these 2D nanomaterials, the permittivity and EA performance of reduced graphene oxide (RGO) have been most widely studied. Well-reduced RGO can significantly enhance the permittivity of polymers,^1,4,6 however, it easily causes impedance mismatch between the air and the composites.⁹ This phenomenon not only limits the EA performance of the composites, but also makes the incident electromagnetic waves more likely to reflect off the surface of the composite. In order to remedy this defect, multi-component composites have been considered to decorate RGO to achieve ideal EA performances, such as ZnO,¹⁰ MoS₂,¹¹ NiFe₂O₄,¹² MoS₂@Fe₃O₄,¹³ CoNi@SiO₂,¹⁴ and V₂O₅/carbon nanotubes (CNTs).¹⁵So far, only a few studies have focused on the regulation of permittivity and the improvement of EA performance of pure RGO.¹ However, the relationship between synthetic parameters and electromagnetic properties is worthy of being explored further. In this study, we discuss the effects of hydrothermal temperature on the permittivity and EA performance of RGO. The results show that regulation of the C/O ratio through controlling the hydrothermal temperature can provide tunable permittivity and an ideal EA performance.Graphene oxide (GO) powder (70 mg) was evenly dispersed in distilled water (1 mg mL⁻¹) by ultrasonication. The dispersion was sealed in a 100 mL Teflon-lined autoclave and maintained at 100 °C for 6 hours to remove the oxygen functional groups, then naturally cooled to room temperature. The resulting precipitate from the reaction was then centrifuged. Then the platelets were collected and freeze-dried for 24 hours. The hydrothermal temperatures were 100, 120, 140, 160 and 180 °C, and we thus designated the RGO products as RGO₁₀₀, RGO₁₂₀, RGO₁₄₀, RGO₁₆₀ and RGO₁₈₀.The micro-morphologies of the as-prepared RGO samples were investigated by SEM analysis and the images show that they have similar 2D flexible layer-like structures (Fig. S1^†). However, with the increase in temperature, the RGO platelets formed large layers with irregular holes.In the XRD spectra (Fig. 1a), the diffraction peaks of graphite (002) move gradually to 24° with the increase of hydrothermal temperature. A peak around 12.5° can be found in RGO₁₀₀, and it suggests that the partial GO has not been well-reduced. On the contrary, RGO₁₄₀, RGO₁₆₀ and RGO₁₈₀ show the diffraction peaks of graphite (100) around 42°, suggesting that a higher degree of graphitization can be achieved by increasing the hydrothermal temperature. A typical and strong D and G band around 1347 and 1581 cm⁻¹ are shown in the Raman spectra of the as-prepared samples (Fig. 1b). On the one hand, removal of oxygen containing groups in GO makes the G band separate from the D band;¹⁶ on the other hand, defects are produced in the lattice structure during the removal of oxygen containing groups, because of the increase of I_D/I_G (Fig. 1c).⁹Open in a separate windowFig. 1XRD (a), Raman (b) and I_D/I_G (c) spectra of RGO₁₀₀, RGO₁₂₀, RGO₁₄₀, RGO₁₆₀ and RGO₁₈₀.The surface chemistry of RGO₁₀₀, RGO₁₂₀, RGO₁₄₀, RGO₁₆₀ and RGO₁₈₀ was measured by XPS. The C/O atomic ratios increase from 6.35 to 9.44 (Table S1^† and Fig. 2f), which suggests that the degree of GO reduction has a positive correlation with the hydrothermal temperature. The C 1s spectra of each RGO sample are shown in Fig. 2, and three typical carbon bonds can be found in each sample, including C–C (∼284.8 eV), C–O (∼287.0 eV), and O C–O (∼288.5 eV).¹ Signals resulting from the decrease of C–O are more significant than those of O C–O, which suggests that most of the oxygen functional groups are removed from the surface of the GO rather than the edges.^17,18Open in a separate windowFig. 2C 1s spectra of RGO₁₀₀ (a), RGO₁₂₀ (b), RGO₁₄₀ (c), RGO₁₆₀ (d) and RGO₁₈₀ (e) using XPS, and the ratios of C/O in each sample (f). Fig. 3 shows the curves of complex permittivity (ε_r) of the as-prepared RGO₁₀₀, RGO₁₂₀, RGO₁₄₀, RGO₁₆₀ and RGO₁₈₀/wax composites, where the filler loading ratios of each RGO sample are 3, 5 and 7 wt%, respectively. With the increase to the loading ratio of each RGO sample, both the ε′ and ε′′ values increase significantly, which means that increasing the loading ratio can enhance the dielectric properties of the RGO/wax composites. This phenomenon can be well explained according to the effective medium theory.⁷ Meanwhile, the values of ε′ and ε′′ under the same filler loading ratios also increase gradually with the increase of hydrothermal temperature. It reveals that tunable permittivity of the composites can be achieved through controlling the reaction temperature of GO.Open in a separate windowFig. 3Frequency-dependent real and imaginary permittivity of RGO₁₀₀ (a and b), RGO₁₂₀ (c and d), RGO₁₄₀ (e and f), RGO₁₆₀ (g and h), and RGO₁₈₀ (i and j), with filler loading ratios of 3, 5 and 7 wt% in the wax composites.The optimal thicknesses of each sample were taken into account for higher EA performances, and the results are shown in Fig. 4. Under the same loading ratio of RGO, the EA performance of each sample becomes more excellent as the hydrothermal temperature of GO increases up until 160 °C. However, when the reaction temperature rises to 180 °C, the EA performances of the composites become worse than before. For each sample, the value for the strongest absorption point (RL_str) and the absorption bandwidth gradually shift toward a lower frequency. This can be explained by the consideration that formation of the quarter-wavelength attenuation requires the absorbing thickness to meet the phase match conditions.⁹ It can be found that the composites loaded with RGO₁₄₀ and RGO₁₆₀ possess much better EA performances than the other samples. Table S2^† summarizes the typical thickness dependent EA performance of the RGO₁₄₀ and RGO₁₆₀/wax composites with the filler loading ratios of 5 and 7 wt%. The composites loaded with 5 wt% RGO₁₄₀ and RGO₁₆₀ respectively show effective EA bandwidths (lower than −10 dB) of 7.04 and 7.56 GHz with RL_str values of −42.86 and −24.78 dB, both at a thickness of 3 mm (Fig. 5a). When the filler loading ratio increased to 7 wt%, the RGO₁₄₀ and RGO₁₆₀/wax composites show effective EA bandwidths of 7.12 and 7.00 GHz with RL_str values of −28.25 and −24.78 dB, respectively, which are also under a thickness of 3 mm (Fig. 5b). From further calculation results, the composite loaded with 5 wt% RGO₁₆₀ has the broadest effective EA bandwidth of 7.56 GHz from 2.9 to 3.2 mm (Fig. 6). When compared with many reported studies (Table S3^†), it is hard to find a material that can demonstrate such a broadband EA performance at such a low filler loading ratio. The results prove that pure RGO can also demonstrate an ideal electromagnetic absorption performance without any other nanomaterials through a most acceptable method.Open in a separate windowFig. 4RL curves of RGO₁₀₀ (a–c), RGO₁₂₀ (d–f), RGO₁₄₀ (g–i), RGO₁₆₀ (j–l) and RGO₁₈₀ (m–o) with filler loading ratios of 3, 5 and 7 wt% in wax composites.Open in a separate windowFig. 5A comparison of the effective EA bandwidths of composites loaded with 5 wt% and 7 wt% RGO₁₄₀ and RGO₁₆₀ at the same thickness of 3 mm.Open in a separate windowFig. 6RL curves of RGO₁₆₀/wax composites, where the filler loading ratio is 5 wt% and the thicknesses are from 2.9 to 3.2 mm.The low values of ε′′ lead to the poor EA performances of the RGO₁₀₀ and RGO₁₂₀/wax composites.¹⁹ The values of ε′′ are gradually enhanced in the RGO₁₄₀, RGO₁₆₀ and RGO₁₈₀/wax composites, however, the EA performance of the RGO₁₈₀/wax composite is not strengthened further. In the Cole–Cole curves (Fig. 7) of the RGO₁₄₀ and RGO₁₆₀/wax composites, several semicircle-like structures can be obviously found in the composites with a filler loading ratio of 3 wt%. On the contrary, no evident semicircle is found in the Cole–Cole curve of the RGO₁₈₀/wax composite, as well as the RGO₁₄₀ and RGO₁₆₀/wax composites with filler loading ratios of 5 and 7 wt%. Instead, it has the tendency to become linear. This reveals that conductivity loss plays the main role in the dielectric loss of this composite, and polarization induced by defects, chemical bonds and interfaces is hidden by the conductivity loss.⁹ Increased conductivity can provide more efficient EA in theory, however, electromagnetic waves may not be able to enter the composite, due to the impedance of the composite which is far less than that of free space.²⁰ A composite has a much higher dielectric loss than others under a very low filler loading ratio of RGO₁₈₀, thus the impedance of the composite will be further depressed with the increased filler loading ratio. Finally, the well-reduced RGO₁₈₀ loses its advantage for EA.Open in a separate windowFig. 7Cole–Cole plots for the RGO₁₄₀/wax (a–c), RGO₁₆₀/wax (d–f), and RGO₁₈₀/wax (g–i) composites.In practice, as an ideal EA material, not only is a broad and strong absorption bandwidth needed, but an accurate coverage of the radar channels is also necessary, for example, the Ku band (12.00–18.00 GHz) for satellite broadcasting, and the X band (8.00–12.00 GHz) for synthetic aperture radar and electron spin resonance apparatus.¹ As shown in Fig. 8 and Table S4,^† both RGO₁₄₀ and RGO₁₆₀ composites with loading ratios of 5 wt% can effectively dissipate incident electromagnetic energy in the whole Ku band at thicknesses of 2.8 and 2.7 mm, as well as the X band at thicknesses of 3.9 and 3.7 mm. Besides 5 wt% loaded RGO, when RGO₁₆₀ is loaded at 7 wt% in the composite, thinner thicknesses of 2.5 and 3.5 mm are required for effective EA in the Ku and X bands, respectively.Open in a separate windowFig. 8The thinnest thicknesses to absorb Ku and X bands effectively: RL curves of a composite loaded with 5 wt% RGO₁₄₀ (a and b) and RGO₁₆₀ (c and d); RL curves of a composite loaded with 7 wt% RGO₁₆₀.     

Down-regulation of HOXB5 inhibits TGF-β-induced migration and invasion in hepatocellular carcinoma cells via inactivation of the PI3K/Akt pathway

HOXB5, a member of the HOX gene family, is a developmental gene which encodes homeoproteins and is known to be a crucial player in development of enteric nervous systems. Recently, HOXB5 was reported to be associated with cancer progression. However, the specific effect of HOXB5 in hepatocellular carcinoma (HCC) remains unclear. In this study, we demonstrated the important role of HOXB5 in HCC. We showed that HOXB5 was up-regulated in HCC tissues and cell lines. Furthermore, down-regulation of HOXB5 inhibited TGF-β-induced HCC cell migration and invasion in vitro and suppressed tumor metastasis in vivo. We also found that the PI3K/Akt pathway partly accounted for the mechanisms underlying the inhibitory effect of HOXB5 down-regulation on TGF-β-induced HCC progression. Taken together, these findings demonstrated that down-regulation of HOXB5 inhibits TGF-β-induced migration and invasion in HCC cells via inactivation of the PI3K/Akt pathway. Thus, HOXB5 may be a novel therapeutic target for HCC treatment.

HOXB5, a member of the HOX gene family, is a developmental gene which encodes homeoproteins and is known to be a crucial player in development of enteric nervous systems.     

Insights into Ag(i)-catalyzed addition reactions of amino alcohols to electron-deficient olefins: competing mechanisms,role of catalyst,and origin of chemoselectivity

The competing mechanisms of Ag(i)-catalyzed chemoselective addition reactions of amino alcohols and electron-deficient olefins leading to the O-adduct or N-adduct products were systematically studied with density functional theory methods. Calculations indicate that the AgHMDS/dppe versus AgOAc/dppe catalytic systems can play different roles and thereby generate two different products. The AgHMDS/dppe system works as a Brønsted base to deprotonate the amino alcohol OH to form the Ag–O bond, which leads to formation of the O-adduct. In contrast, the AgOAc/dppe system mainly acts as a Lewis acid to coordinate with O and N atoms of the amino alcohol, but it cannot act as the Brønsted base to further activate the OH group because of its weaker basicity. Therefore, the AgOAc/dppe catalyzed reaction has a mechanism that is similar to the non-catalyzed reaction, and generates the same N-adduct. The obtained insights will be important for rational design of the various kinds of cooperatively catalyzed chemoselective addition reactions, including the use of the less nucleophilic hydroxyl groups of unprotected amino alcohols.

The origin of the chemoselectivities of Ag(i)-catalyzed addition reactions of amino alcohols to olefin has been predicted for the first time.