Spectroscopy

光谱学
  • 文章类型: Journal Article
    本研究使用密度泛函理论(DFT)在高斯09W软件上分析阿司匹林分子(C9H8O4)。首先,使用DFT方法以B3LYP功能和6-311G(d,P)基础设置。采用全球反应性研究来了解阿司匹林在气体和溶剂水中对阴离子和中性状态的反应性。为了了解轨道在化学稳定性和电子传导性中的参与,我们计算了HOMO-LUMO。使用热化学来理解分子的热力学功能。采用分子静电势(MEP)来了解阿司匹林的理化性质。我们观察了Mulliken原子电荷来计算阿司匹林的原子电荷。最后,标题分子的UV-Vis,FTIR,和拉曼光谱进行了分析,并与实验数据进行了比较。
    This study analyzed the aspirin molecule (C9H8O4) using Density Functional Theory (DFT) on Gaussian 09W software. First, the structure of aspirin was optimized using the DFT method with the B3LYP functional and the 6-311+G (d,p) basis set. A global reactivity study was employed to understand the reactivity of aspirin in gas and solvent water for both anion and neutral states. To understand the involvement of orbitals in chemical stability and electron conductivity, we calculated the HOMO-LUMO. The thermodynamic function of a molecule was understood using thermochemistry. Molecular Electrostatic Potential (MEP) was employed to understand the physiochemical properties of aspirin. We observed the Mulliken atomic charge to calculate the atomic charge of aspirin. Finally, the title molecule\'s UV-Vis, FTIR, and Raman spectra are analyzed and compared with the experimental data.
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  • 文章类型: Journal Article
    表面活性剂对流体界面的吸附发生在许多技术和日常生活环境中。所形成的吸附层在界面处的覆盖率和其它性质决定了表面活性剂在所需应用方面的性能。鉴于这些应用的重要性,对表面活性剂吸附层的全面表征和理解有很大的需求。在这次审查中,我们提供了合适的实验和基于模拟的技术的概述,并回顾了用于研究表面活性剂吸附层的文献。我们得出的结论是,虽然这些技术已成功应用于研究水不溶性表面活性剂的Langmuir单层,它们在水溶性表面活性剂吉布斯吸附层研究中的应用尚未得到充分开发。最后,我们强调这些方法的巨大潜力,提供了一个更深入的了解可溶性表面活性剂在界面的行为,这对于优化它们在各种应用中的性能至关重要。
    Adsorption of surfactants to fluid interfaces occurs in numerous technological and daily-life contexts. The coverage at the interface and other properties of the formed adsorption layers determine the performance of a surfactant with regard to the desired application. Given the importance of these applications, there is a great demand for the comprehensive characterization and understanding of surfactant adsorption layers. In this review, we provide an overview of suitable experimental and simulation-based techniques and review the literature in which they were used for the investigation of surfactant adsorption layers. We come to the conclusion that, while these techniques have been successfully applied to investigate Langmuir monolayers of water-insoluble surfactants, their application to the study of Gibbs adsorption layers of water-soluble surfactants has not been fully exploited. Finally, we emphasize the great potential of these methods in providing a deeper understanding of the behavior of soluble surfactants at interfaces, which is crucial for optimizing their performance in various applications.
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  • 文章类型: Journal Article
    咖啡,一种全球消费的饮料,由于可能存在酒精化合物,引起了伊斯兰法学的关注。本研究旨在利用1HNMR光谱的灵敏度和可靠性定量醇化合物,如乙醇,糠醇,和5-(羟甲基)糠醛(HMF)在商业速溶咖啡中。使用先进的1H核磁共振(NMR)光谱法以及统计总相关光谱法(STOCSY)和分辨率增强(RED)-STORM进行七种产物的分析。100mg样品的分析显示不存在乙醇。在选定的商业速溶咖啡样品中糠醇和HMF的量为0.817μg和0.0553μg,分别。这项研究证明了1HNMR光谱在精确定量各种应用中的痕量成分中的实用性。
    Coffee, a globally consumed beverage, has raised concerns in Islamic jurisprudence due to the possible presence of alcohol compounds. This research aims to utilise the sensitivity and reliability of 1H NMR spectroscopy in the quantification of alcohol compounds such as ethanol, furfuryl alcohol, and 5-(hydroxymethyl) furfural (HMF) in commercial instant coffee. Analysis of seven products was performed using advanced 1H Nuclear Magnetic Resonance (NMR) spectroscopy together with Statistical Total Correlation Spectroscopy (STOCSY) and Resolution-Enhanced (RED)-STORM. The analysis of the 100 mg sample revealed the absence of ethanol. The amount of furfuryl alcohol and HMF in the selected commercial instant coffee samples was 0.817 μg and 0.0553 μg, respectively. This study demonstrates the utility of 1H NMR spectroscopy in accurate quantification of trace components for various applications.
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  • 文章类型: Journal Article
    阴离子辅助配体在稀土(RE)金属配合物的构建中起着至关重要的作用,因为它对分子的稳定性有很大的影响,并产生了大量应用中感兴趣的新兴电子特性。由于这些离子固有的高亲氧性,在RE化学中高度追求包含氧供体原子的支持配体。几乎不使用的双(酰基)磷化物(BAP)配体具有氧配位位点,并含有磷化物主链,使其对RE配位化学具有吸引力。这里,我们将双(均三甲酰基)磷化物(mesBAP)作为辅助配体整合到REIII化学中,以生成包含BAP配体的第一个双核三价RE配合物;[{mesBAP}2RE(THF)(μ-Cl)]2(RE=Y,(1),Gd(2),和Dy(3);THF=四氢呋喃)。每个RE中心连接到两个单阴离子mesBAP配体,一个THF分子和一个氯离子。所有三个分子都通过单晶X射线衍射进行了表征,31PNMR,IR和UV-Vis光谱。31P,在反磁性钇同源物1上的1H和13CNMR证实了不对称配体配位。对2进行的DFT计算提供了对电子结构的了解。通过SQUID磁力法研究了2和3的磁性。GdIII离子表现出弱的反铁磁耦合,由DFT结果证实。
    Anionic ancillary ligands play a critical role in the construction of rare earth (RE) metal complexes due to the large influence on the stability of the molecule and engendering emergent electronic properties that are of interest in a plethora of applications. Supporting ligands comprising oxygen donor atoms are highly pursued in RE chemistry owing to the high oxophilicity innate to these ions. The scarcely employed bis(acyl)phosphide (BAP) ligands feature oxygen coordination sites and contain a phosphide backbone rendering it attractive for RE-coordination chemistry. Here, we integrate bis(mesitoyl)phosphide (mesBAP) as an ancillary ligand into REIII chemistry to generate the first dinuclear trivalent RE complexes containing BAP ligands; [{mesBAP}2RE(THF)(μ-Cl)]2 (RE = Y, (1), Gd (2), and Dy (3); THF = tetrahydrofuran). Each RE center is ligated to two monoanionic mesBAP ligands, one THF molecule and one chloride ion. All three molecules were characterized through single-crystal X-ray diffraction, 31P NMR, IR and UV-Vis spectroscopy. 31P, 1H and 13C NMR on the diamagnetic yttrium congener 1 confirm asymmetric ligand coordination. DFT calculations conducted on 2 provided insight into the electronic structure. The magnetic properties of 2 and 3 were investigated via SQUID magnetometry. The GdIII ions exhibit weak antiferromagnetic coupling, corroborated by DFT results.
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  • 文章类型: Journal Article
    电子-声子(e-p)耦合在各种物理现象中起着至关重要的作用,e-p耦合的调控对于高性能材料的探索和设计至关重要。然而,目前对这一主题的研究缺乏准确的量化,阻碍了对底层物理过程及其应用的进一步理解。在这项工作中,我们证明了e-p偶联的定量调控,通过压力工程和局部显微镜检查。我们成功地观察到分层CrBr3中独特的振动模式和强烈的斯托克斯位移,这是e-p耦合的明显特征。这使我们能够在实际样品温度下实现对Huang-Rhys因子的精确量化,从而准确地确定e-p耦合强度。我们进一步揭示了压力有效地调节CrBr3中的e-p耦合,S值显着增加了40%。我们的结果提供了一种量化和调节e-p耦合的方法,可用于探索和设计具有目标e-p耦合强度的功能材料。
    Electron-phonon (e-p) coupling plays a crucial role in various physical phenomena, and regulation of e-p coupling is vital for the exploration and design of high-performance materials. However, the current research on this topic lacks accurate quantification, hindering further understanding of the underlying physical processes and its applications. In this work, we demonstrate quantitative regulation of e-p coupling, by pressure engineering andin-situspectroscopy. We successfully observe both a distinct vibrational mode and a strong Stokes shift in layered CrBr3, which are clear signatures of e-p coupling. This allows us to achieve precise quantification of the Huang-Rhys factorSat the actual sample temperature, thus accurately determining the e-p coupling strength. We further reveal that pressure efficiently regulates the e-p coupling in CrBr3, evidenced by a remarkable 40% increase inSvalue. Our results offer an approach for quantifying and modulating e-p coupling, which can be leveraged for exploring and designing functional materials with targeted e-p coupling strengths.
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  • 文章类型: Journal Article
    通过结肠镜检查筛查结直肠癌(CRC)改善了患者的预后;然而,它仍然是癌症相关死亡率的第三大原因,需要新的策略来改善筛查。这里,我们提出了一种基于光谱光学相干断层扫描(OCT)的光学活检技术。深度分辨OCT图像作为波长的函数被分析以测量光学组织性质并且用作机器学习算法的输入。以前,我们用这种方法分析了小鼠结肠息肉.这里,我们将该方法扩展到体外检查人类活检的结肠上皮组织样本。光学特性被用作新型深度学习架构的输入,识别组织类型的准确率高达97.9%。SOCT参数用于创建假彩色人脸OCT图像,深度学习分类用于按组织类型进行视觉分类。这项研究将SOCT推向了结肠上皮分析的临床应用。
    Screening for colorectal cancer (CRC) with colonoscopy has improved patient outcomes; however, it remains the third leading cause of cancer-related mortality, novel strategies to improve screening are needed. Here, we propose an optical biopsy technique based on spectroscopic optical coherence tomography (OCT). Depth resolved OCT images are analyzed as a function of wavelength to measure optical tissue properties and used as input to machine learning algorithms. Previously, we used this approach to analyze mouse colon polyps. Here, we extend the approach to examine human biopsied colonic epithelial tissue samples ex vivo. Optical properties are used as input to a novel deep learning architecture, producing accuracy of up to 97.9% in discriminating tissue type. SOCT parameters are used to create false colored en face OCT images and deep learning classifications are used to enable visual classification by tissue type. This study advances SOCT toward clinical utility for analysis of colonic epithelium.
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  • 文章类型: Journal Article
    生物制造利用改良的微生物系统可持续地生产用于农业的商业上重要的生物分子,能源,食物,材料,和制药行业。然而,需要解决与无损和高通量代谢物筛选相关的技术挑战,以充分释放合成生物学和可持续生物制造的潜力。
    这个观点概述了工业细胞菌株开发计划中使用的当前分析筛选工具,并引入了无标签振动光谱显微镜作为替代对比机制。
    我们概述了当前在设计的“测试”部分中使用的分析仪器,build,test,学习合成生物学的周期。然后,我们重点介绍了拉曼散射和红外吸收成像技术的最新进展,这提高了分子特异性和灵敏度。
    高分辨率化学成像方法的最新发展允许更大的吞吐量,而不影响图像对比度。我们提供了支持与微流体集成以在单细胞水平进行快速筛查所需的未来工作的路线图。
    对代谢物的净表达进行定量,可以鉴定具有导致生物分子产生增加的代谢途径的细胞,这对于提高产量和降低工业生物制造成本至关重要。振动显微镜仪器的技术进步将极大地有利于生物材料作为非破坏性细胞筛选的补充方法。
    UNASSIGNED: Biomanufacturing utilizes modified microbial systems to sustainably produce commercially important biomolecules for use in agricultural, energy, food, material, and pharmaceutical industries. However, technological challenges related to non-destructive and high-throughput metabolite screening need to be addressed to fully unlock the potential of synthetic biology and sustainable biomanufacturing.
    UNASSIGNED: This perspective outlines current analytical screening tools used in industrial cell strain development programs and introduces label-free vibrational spectro-microscopy as an alternative contrast mechanism.
    UNASSIGNED: We provide an overview of the analytical instrumentation currently used in the \"test\" portion of the design, build, test, and learn cycle of synthetic biology. We then highlight recent progress in Raman scattering and infrared absorption imaging techniques, which have enabled improved molecular specificity and sensitivity.
    UNASSIGNED: Recent developments in high-resolution chemical imaging methods allow for greater throughput without compromising the image contrast. We provide a roadmap of future work needed to support integration with microfluidics for rapid screening at the single-cell level.
    UNASSIGNED: Quantifying the net expression of metabolites allows for the identification of cells with metabolic pathways that result in increased biomolecule production, which is essential for improving the yield and reducing the cost of industrial biomanufacturing. Technological advancements in vibrational microscopy instrumentation will greatly benefit biofoundries as a complementary approach for non-destructive cell screening.
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  • 文章类型: Journal Article
    电子转移研究中的一个长期存在的问题涉及驱动电子转移或局部化的集体核运动的数量和身份。众所周知,这些核运动通常会聚集到所谓的电子转移坐标中。在这项理论研究中,我们证明了非对称和对称振动运动都是桥接系统固有的,两者都需要解释它们的价间电荷转移带的特征形状。使用两状态Marcus-Hush模型的属性,我们从从头计算中将这两个坐标识别和量化为正常模式的线性组合。这种量化提供了对潜在耦合的访问,参与电子转移的势能面的重组能和曲率,独立于对感兴趣的系统的任何先前假设。我们用Creutz-Taube离子展示了这些主张,典型的III类混合价络合物。我们发现对称维度是不对称能带形状的原因,并将其追溯到该维度中接地和激发态电势的偏移。对称尺寸的重要性源于几何相关的耦合,这反过来又是完善的超交换机制的自然结果。对称和反对称运动与超交换机制之间的概念联系似乎是桥接系统的一般结果。
    A long-standing question in electron transfer research concerns the number and identity of collective nuclear motions that drive electron transfer or localisation. It is well established that these nuclear motions are commonly gathered into a so-called electron transfer coordinate. In this theoretical study, we demonstrate that both anti-symmetric and symmetric vibrational motions are intrinsic to bridged systems, and that both are required to explain the characteristic shape of their intervalence charge transfer bands. Using the properties of a two-state Marcus-Hush model, we identify and quantify these two coordinates as linear combinations of normal modes from ab initio calculations. This quantification gives access to the potential coupling, reorganization energy and curvature of the potential energy surfaces involved in electron transfer, independent of any prior assumptions about the system of interest. We showcase these claims with the Creutz-Taube ion, a prototypical Class III mixed valence complex. We find that the symmetric dimension is responsible for the asymmetric band shape, and trace this back to the offset of the ground and excited state potentials in this dimension. The significance of the symmetric dimension originates from geometry dependent coupling, which in turn is a natural consequence of the well-established superexchange mechanism. The conceptual connection between the symmetric and anti-symmetric motions and the superexchange mechanism appears as a general result for bridged systems.
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  • 文章类型: Journal Article
    在过去的20年里,胎儿脑MR成像分析方法有了显著的发展。本文深入研究了结构成像的细节,扩散成像,功能磁共振成像,和光谱学,强调运动矫正的最新进展,胎儿大脑发育图谱,挑战和创新。此外,本文探讨了这些先进的影像学技术在理解和诊断胎儿脑发育和异常中的临床应用。
    Over the last 20 years, there have been remarkable developments in fetal brain MR imaging analysis methods. This article delves into the specifics of structural imaging, diffusion imaging, functional MR imaging, and spectroscopy, highlighting the latest advancements in motion correction, fetal brain development atlases, and the challenges and innovations. Furthermore, this article explores the clinical applications of these advanced imaging techniques in comprehending and diagnosing fetal brain development and abnormalities.
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  • 文章类型: Journal Article
    随着时间的推移,微生物感染的影响越来越大,这是发达国家和发展中国家死亡的主要原因之一。粘菌素被认为是主要多药耐药(MDR)引起的感染的最后选择的抗生素,革兰氏阴性菌,如肠杆菌,不动杆菌属,还有铜绿假单胞菌.诊断这些抗性物种的现有方法相对较慢并且需要2至3天。在这项工作中,我们提出了一种基于拉曼光谱和重水的新型跨学科方法来鉴定粘菌素抗性微生物。我们的假设是基于这样一个事实,即耐药细菌在含有抗生素和重水的培养基中具有代谢活性,这些细菌会吸收氘而不是氢到新合成的脂质和蛋白质中。这种效应将产生“C-D”键特异性拉曼光谱标记。在光谱图中成功鉴定该条带可以确认粘菌素抗性细菌的存在。我们已经验证了这种方法在识别人工尿液中掺入的粘菌素抗性细菌中的功效,并比较了在不同细菌浓度下的敏感性。总体发现表明,重水可以潜在地用作在临床可实施时间下通过尿液鉴定代谢活性粘菌素抗性细菌的合适拉曼探针,并且可以在验证后用于临床设置。
    The impact of microbial infections is increasing over time, and it is one of the major reasons for death in both developed and developing countries. colistin is considered as the antibiotic of last choice for infections brought by major multidrug-resistant (MDR), gram-negative bacteria such as Enterobacter species, Acinetobacter species, and Pseudomonas aeruginosa. Existing approaches to diagnose these resistant species are relatively slow and take up to 2 to 3 days. In this work, we propose a novel interdisciplinary method based on Raman spectroscopy and heavy water to identify colistin-resistant microbes. Our hypothesis is based on the fact that resistant bacteria will be metabolically active in the culture medium containing antibiotics and heavy water, and these bacteria will take up deuterium instead of hydrogen to newly synthesized lipids and proteins. This effect will generate a \'C - D\' bond-specific Raman spectral marker. Successful identification of this band in the spectral profile can confirm the presence of colistin-resistant bacteria. We have validated the efficacy of this approach in identifying colistin-resistant bacteria spiked in artificial urine and have compared sensitivity at different bacterial concentrations. Overall findings suggest that heavy water can potentially serve as a suitable Raman probe for identifying metabolically active colistin-resistant bacteria via urine under clinically implementable time and can be used in clinical settings after validation.
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