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1.
《Dental materials》2022,38(6):924-934
ObjectivesTo study the oxide layer stability of certified dental implants of system "P", made based on TiO2 alloy with carbon coating. To perform a comparative statistical analysis of the obtained data with the available data for the dental implants of systems "A" and "B".MethodsX-ray microtomography and X-ray fluorescence analysis were used to study soft tissue biopsy specimens. Supernatants were studied by dynamic light scattering and transmission electron microscopy when simulating free emission of nanoscale metal oxide particles from the surface of dental implants as well as when simulating physical loading. A comparative analysis of three parameters of nanoscale particles was performed by statistical data analysis. The surface of the "P" system dental implant with surface treatment was analyzed by scanning electron microscopy.ResultsBoth free emission of nanoscale oxide layer particles and yield of nano- and microscale particles during simulation of physical load were confirmed. Statistically significant differences were noted in a comparative analysis of the size and frequency of occurrence of these particles in the supernatants obtained from the surfaces of three dental implant systems. The elemental composition of the particles and the composition and structure of the "P" system dental implants themselves were analyzed.SignificanceThe developed method of dynamic light scattering can be used to compare the stability of the oxide layer of standardized medical products manufactured on the basis of the TiO2 alloy.  相似文献   
2.
目的 建立一种联合表面增强拉曼散射(SERS)与卷积神经网络(CNN)的方法,用于耐甲氧西林金黄色葡萄球菌(MRSA)和对甲氧西林敏感金黄色葡萄球菌(MSSA)的准确鉴定。方法 合成带正电的纳米银颗粒(AgNPs+)作为SERS基底,测量MRSA和MSSA的SERS指纹谱并制作数据集,构建浅层一维CNN网络并在该数据上训练生成MRSA/MSSA二分类模型。结果 合成的AgNPs+能够通过静电引力紧密地吸附在细菌菌体表面并产生显著的SERS效应,在654、731 cm-1等7个波段均有明显的拉曼峰被增强出。提出的SERS-CNN方法用于MRSA和MSSA检测的准确率超过94.5%,重现性小于5%,检测灵敏度达到102 cells/mL。结论 建立的联合SERS与CNN的方法可用于MRSA的准确检测。  相似文献   
3.
Introduction and Aim: The indiscriminate use and adverse effects of the main conventional antifungal agents compromise the effectiveness of treating vulvovaginal candidiasis (VVC), mainly caused by the species Candida albicans. This study evaluated the effectiveness of photodynamic therapy (PDT) and the in vitro and in vivo anti-candida potential of the hypericin (HYP)-loaded nanostructured lipid carriers (NLC). Materials and Methods: Empty NLC and NLC-HYP were characterized by the dynamic light scattering technique and transmission electron microscopy to evaluate the average particle size distribution and its morphologies. The in vitro inhibition photodynamic effect of the systems was tested to reduce the planktonic viability of C. albicans. The therapeutic assay photodynamic of the systems was performed to treat VVC in mice. Results: Empty NLC and NLC-HYP presented values of average hydrodynamic diameter, polydispersity index, and ζ-potential from 136 to 133 nm, 0.16 to 0.22, and -18 to -30 mV, respectively, on day 30. Microscopically, the systems showed spherical morphologies and nanoscale particles. Furthermore, in the in vitro inhibition assay, the treatment of PDT with NLC-HYP (NLC-HYP+) showed a significant reduction of the C. albicans planktonic viability compared to YNB negative control after 5 min of LED light irradiation. In the in vivo therapeutic assay, the antifungal group (vaginal antifungal cream) and NLC-HYP+ evaluated in the dark and by PDT, respectively, had a significant log10 reduction in fungal burden compared to the infected group on day 8 of the VVC treatment. Conclusion: Due to the in vitro and in vivo anti-candida potential, PDT-mediated systems can be an effective strategy in VVC therapy.  相似文献   
4.
5.
The nonsteroidal anti-inflammatory drugs elevate cardiovascular risk, perhaps, due to their accumulation in the heart and kidneys. We designed nanodelivery systems for cardiotoxic diclofenac to reduce its presence in these organs. Diclofenac ethyl ester (DFEE) was encapsulated in traceable micelles based on poly(ethylene oxide)-b-poly(ε-caprolactone) (DFEE-PCL-TM) or poly(ethylene oxide)-b-poly(α-benzyl carboxylate-ε-caprolactone) (DFEE-PBCL-TM). Diclofenac pharmacokinetics and tissue distribution were studied after intravenous (iv) and intraperitoneal administration of the nanoformulations and compared with those after iv doses of free diclofenac (n = 3-6/group). The average diameters for DFEE-PBCL-TM and DFEE-PCL-TM were 37.2 ± 0.06 and 45.1 ± 0.06 nm, respectively. Drug concentration dropped below the assay sensitivity after free drug administration in 6 h, but persisted for 24 h following DFEE-PBCL-TM (2.3 ± 1.4 μg/mL) and DFEE-PCL-TM (1.9 ± 0.6 μg/mL) iv administration. The diclofenac heart:blood and kidney:blood ratios were 5- to 12-fold lower with the nanoformulations than with free diclofenac. Near-infrared fluorescence measurements in tissues suggested exposure patterns to nanocarriers parallel with those achieved for delivered diclofenac by nanoformulations. Administration of DFEE-PCL-TM by iv or intraperitoneal injection, resulted in comparable pharmacokinetics and 6 h postdose near-infrared fluorescence in the heart, kidneys, liver, and spleen. When compared to each other, DFEE-PBCL-TM showed significantly lower diclofenac levels in the heart compared to DFEE-PCL-TM (0.3 ± 0.03 vs. 0.5 ± 0.1 μg/g). Developed nanoformulations of diclofenac prolonged diclofenac circulation and reduced its presence in the heart and kidneys, strongly suggesting cardiac-safe delivery vehicles for diclofenac.  相似文献   
6.
BackgroundAlthough various studies have been conducted to demonstrate the possibility of Raman spectroscopy (RS) as a diagnostic tool for prostate cancer (PC), it is difficult to use it in the real clinical area because of imitations in various research processes. Therefore, we did a systematic review and meta-analysis about the accuracy in diagnostic use of RS for PC.MethodsA literature search was done using PubMed, Embase, and Cochrane library databases in March 2019 to analyze the accuracy of RS for diagnosis of PC. The accuracy of RS for diagnosis of PC was evaluated by means of pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and summary receiver operating characteristic (SROC).ResultsFive studies were included for qualitative analysis by screening the remaining articles according to the inclusion and exclusion criteria by means of a systematic review. The pooled sensitivity and specificity of RS were 0.89 (95% CI: 0.87–0.91) and 0.91 (95% CI: 0.89–0.93), respectively. The overall PLR and NLR were 9.12 (95% CI: 4.15–20.08) and 0.14 (95% CI: 0.07–0.29), respectively. The DOR of RS demonstrated high accuracy (73.32; 95% CI: 18.43–291.73). The area under the curves (AUCs) of SROC curves was 0.93.ConclusionsRS is an optical diagnostic method with high potential for diagnosis and grading of PC and has advantages of real-time and convenient use. In order to consider real-time use of RS in an actual clinical setting, more studies for standardization and generalization of RS performance and analytical method must be conducted.  相似文献   
7.
目的采用高效液相色谱-蒸发光散射检测方法(HPLC-ELSD)建立同时测定知母药材中新芒果苷、芒果苷、知母皂苷BⅡ、宝藿苷Ⅰ及知母皂苷AⅢ的含量测定方法。方法采用Agilent poroshell 120 EC-C18柱,流动相采用乙腈-0.2%醋酸水系统,梯度洗脱;柱温为30℃,流速为0.7 ml/min;蒸发光散射检测器以氮气为雾化气,雾化气温度为40℃,漂移管温度为90℃,氮气体积流量为2.0 L/min;进样量为20μl。结果5种成分均能达到基线分离,新芒果苷24.1~386μg/ml(r=0.9993)、芒果苷23.2~371μg/ml(r=0.9986)、知母皂苷BⅡ54.2~867.2μg/ml(r=0.9956)、宝藿苷Ⅰ5.3~84.8μg/ml(r=0.9968)、知母皂苷AⅢ10~160μg/ml(r=0.9989)的浓度范围内呈现良好的线性关系。5种成分的平均加样回收率在101.8%~105.0%之间,重复性RSD小于2.4%,知母药材中上述5种成分含量分别为1.62%、0.82%、7.36%、0.07%、0.34%。结论该方法操作简便、准确、灵敏度高,可用于知母药材的多指标成分定量测定。  相似文献   
8.
拉曼光谱可以用于识别和描述微生物的特征,作为当今微生物分类鉴定研究的热点。 相比于传统的微生物分离培养技术和分子生物学鉴定技术,拉曼技术具有免培养、快速和高效等优点。 随着光学领域拉曼技术和分子生物学的结合发展,使得微生物的鉴定变得更加高效快捷。 拉曼显微光谱结合稳定同位素探针、荧光原位杂交和光镊技术,为研究生态系统中不可培养微生物的功能和生理提供了一种独立的方法。 显微共聚焦拉曼技术在细菌分类鉴定中具有巨大的应用前景。 本文主要阐述拉曼光谱技术的基础知识和显微共聚焦拉曼技术在细菌分类鉴定中的研究进展,并对该技术的优缺点进行总结和评价,旨在为拉曼光谱技术应用于微生物学的研究提供参考。  相似文献   
9.
The ability to develop highly active and low-cost electrocatalysts represents an important endeavor toward accelerating sluggish water-oxidation kinetics. Herein, we report the implementation and unraveling of the photothermal effect of spinel nanoparticles (NPs) on promoting dynamic active-sites generation to markedly enhance their oxygen evolution reaction (OER) activity via an integrated operando Raman and density functional theory (DFT) study. Specifically, NiFe2O4 (NFO) NPs are first synthesized by capitalizing on amphiphilic star-like diblock copolymers as nanoreactors. Upon the near-infrared light irradiation, the photothermal heating of the NFO-based electrode progressively raises the temperature, accompanied by a marked decrease of overpotential. Accordingly, only an overpotential of 309 mV is required to yield a high current density of 100 mA cm−2, greatly lower than recently reported earth-abundant electrocatalysts. More importantly, the photothermal effect of NFO NPs facilitates surface reconstruction into high-active oxyhydroxides at lower potential (1.36 V) under OER conditions, as revealed by operando Raman spectroelectrochemistry. The DFT calculation corroborates that these reconstructed (Ni,Fe)oxyhydroxides are electrocatalytically active sites as the kinetics barrier is largely reduced over pure NFO without surface reconstruction. Given the diversity of materials (metal oxides, sulfides, phosphides, etc.) possessing the photo-to-thermal conversion, this effect may thus provide a unique and robust platform to boost highly active surface species in nanomaterials for a fundamental understanding of enhanced performance that may underpin future advances in electrocatalysis, photocatalysis, solar-energy conversion, and renewable-energy production.

Motivated by the need for accelerating sluggish reaction kinetics at the anode (1, 2), the focus of water electrolysis has been centered heavily on oxygen evolution reaction (OER) toward sustainable hydrogen fuel production. To date, there has been much effort in developing low-cost yet high-performance earth-abundant transition-metal alternatives to commonly used noble metals for OER. Intriguingly, many Ni-, Co-, Fe-, and Mn-based oxides experience a dynamic surface-reconstruction process to form more active oxyhydroxides, which are recognized as true catalytically active species for OER in alkaline media (3, 4). Among various transition metal-based OER catalysts, bimetal spinel-structured oxides in the form of AB2O4 (A and B are different metal ions) have garnered much attention due to their rich compositions, electron configurations, and valence states (5). Interestingly, inverse spinel NiFe2O4 (NFO), in principle, exhibits enhanced catalytic activity toward OER because of the presence of multivalent elements (i.e., Ni3+/Ni2+ and Fe3+/Fe2+) (6). It is important to note that studies on facilitating the surface reconstruction of NFO to achieve high-performance OER are relatively few, and a fundamental understanding as to what makes the derived OER catalysts perform well remains elusive.Recently, introducing thermal energy to promote electrocatalytic conversion has attracted significant interest (710). The thermal energy could accelerate the motion of reactant molecules, promote their effective collisions during the reaction, and thus make it easier to overcome the activation barrier (11, 12). Moreover, the use of thermal energy could also promote the surface reconstruction of catalysts into highly active species and accelerate the electrocatalytic kinetics, thereby leading to improved efficiency (13). Electrocatalysts with photothermal effect (referred to as photothermal electrocatalysts) enable in situ heating due to photo-to-thermal conversion under illumination with visible or near-infrared (NIR) light, thereby dispensing with the need for extra devices required to provide thermal energy. More importantly, in sharp contrast to common approaches where the entire solution is heated (14), the photothermal effect is localized on electrocatalysts themselves (15), thus effectively enabling heat modulation to a defined region (i.e., the working electrode). Despite recent impressive advances in transition metal oxides (e.g., Fe3O4 and Co3O4) as photothermal agents for cancer therapy (15), their implementations for photothermal-assisted OER, in particular spinel oxides, are comparatively few and limited in scope. Moreover, it has been reported that Ni- and Co-based OER catalysts are prone to surface reconstruction into highly active oxyhydroxides (16, 17). Surprisingly, the photothermal effect on promoting surface reconstruction in spinel oxide catalysts has yet to be explored.Herein, we report an integrated operando Raman and density functional theory (DFT) plus Hubbard U (DFT + U) study to exercise and unveil the photo-to-thermal conversion of inverse spinel oxide nanoparticles (NPs) in promoting the generation of dynamic active sites via surface reconstruction into oxyhydroxides and thus greatly enhancing their OER activity. First, a series of amphiphilic star-like poly(acrylic acid)-block-poly(styrene-co-acrylonitrile) (denoted PAA-b-PSAN) diblock copolymers with a well-defined molecular weight (MW) and low polydispersity index (PDI) are exploited as nanoreactors to synthesize a set of PSAN-ligated NFO NPs with different sizes and PSAN chain lengths. The effects of the NFO NP sizes and the outer PSAN chain lengths on catalytic activity of NFO NPs are then scrutinized. Interestingly, NFO NPs of the largest size (∼12 nm) ligated with the shortest PSAN chains (Mn = 7K) display the best OER reactivity on a glassy carbon (GC) electrode in alkaline media as a result of the high fraction of the exposed electrochemically active surface area and the fastest electrocatalytic kinetics. Subsequently, the photothermal effect of PSAN-ligated NFO NPs is exploited to promote their surface reconstruction and thus boost OER. More importantly, an operando Raman spectroelectrochemistry study is performed to unveil the mechanism of photothermal-assisted enhancement in OER reaction, revealing the emergence of electrocatalytically active γ-NiOOH at a lower potential (1.36 V) during the surface-reconstruction process with a photothermal effect. Finally, the first-principle calculations substantiate that the reconstructed surface, i.e., (Ni,Fe)oxyhydroxides, plays a pivotal role as the active site for electrocatalytic reaction. As such, photothermal electrocatalysts (e.g., metal oxides, sulfides, phosphides, etc.) may render significantly low overpotential and fast OER kinetics, representing an array of important materials that couple the localized heating with electrochemistry for effective renewable-energy production.  相似文献   
10.
目的:年龄相关性黄斑变性(AMD)是致盲的主要原因之一。氧化应激所引起的视网膜色素上皮(RPE)细胞变性在AMD的发病机制中发挥了关键作用。本文利用无创、无需标签、高灵敏度的拉曼光谱探究川芎嗪对氧化损伤的人RPE细胞的保护机制。方法:进行拉曼光谱采集之前,将除对照组外的其余两组RPE细胞(ARPE-19)用200 μmol/mL H2O2预孵育,24 h后在保护组细胞中加入200 μmol/mL川芎嗪。所有干预结束后,用MultiskanGO (Thermo, USA)微板法测定细胞内活性氧自由基的含量,用InVia微拉曼系统对3组细胞进行拉曼光谱分析。结果:活性氧检测显示川芎嗪对H2O2诱导的RPE细胞氧化应激损伤有较好的抑制作用。拉曼光谱结果显示细胞氧化应激损伤主要体现在氨基酸类分子上,而川芎嗪的加入不仅逆转了归属于脂质的谱带810 cm-1和840 cm-1峰强度比值的变化趋势,还使H2O2干预后显著提高的归属于各氨基酸谱带的峰强度值有所下降。与之前激光光镊拉曼光谱结果不同,活性氧自由基没有触发酰胺的脱酰胺反应,反而是川芎嗪的干预使得归属于酰胺的拉曼光谱强度发生改变。结论:通过对人RPE细胞拉曼光谱变化的分析,揭示过氧化氢和抗氧化剂川芎嗪潜在的作用靶点,为更好地探究RPE细胞氧化应激的损伤机制奠定了基础。  相似文献   
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