Infrared spectroscopy

红外光谱
  • 文章类型: Journal Article
    全球对水泥需求的增加对温室气体排放和资源消耗产生了重大影响。需要可持续的替代方案。这项研究调查了掺入20wt。五种工业废物的%-吸入粉尘,氧化铝生产的赤泥,电滤粉尘,以及从食品补充剂生产和部分稳定的工业废物中提取污泥,作为传统水泥的潜在替代品。使用一致的合成方法来制备地质聚合物,它们的物理化学特征,机械,和生物学特性。离子电导率和pH测量以及完整性测试,热重分析(TGA),和浸出分析用于确认合成的地质聚合物的稳定性。傅里叶变换红外(FT-IR)光谱用于跟踪地质聚合发生。离子电导率的结果,pH值,和完整性表明,合成的GP是宏观稳定的。TGA显示,主要的质量损失可归因于水脱水和地质聚合物网络中截留的水。由于部分废物降解,只有充满来自氧化铝生产的红泥粉末的GP经历了23%的质量损失。FT-IR显示主要Si-O-(Si或Al)吸收带红移,表明成功的地质聚合物网络形成。此外,与对照(22MPa)相比,大多数充满废物的GP表现出更高的抗压强度(37.8-58.5MPa)。仅填充有部分稳定的工业废物的GP具有较低的机械强度,因为其结构是高度多孔的,因为在地质聚合反应期间气体形成。尽管充满吸尘废物的GP具有很高的抗压强度(58.5MPa),浸出的Sb浓度为25ppm,这限制了它的使用。最终,由于碱性环境和能够与细菌膜反应的金属阳离子的存在,所有样品还显示出对大肠杆菌和金黄色葡萄球菌的有效抗菌活性。研究结果揭示了在多个应用领域中回收这些废物的可能性。
    The increasing global demand for cement significantly impacts greenhouse gas emissions and resource consumption, necessitating sustainable alternatives. This study investigates fresh geopolymer (GP) pastes incorporating 20 wt.% of five industrial wastes-suction dust, red mud from alumina production, electro-filter dust, and extraction sludges from food supplement production and from partially stabilized industrial waste-as potential replacements for traditional cement. Consistent synthesis methods are used to prepare the geopolymers, which are characterized for their physicochemical, mechanical, and biological properties. Ionic conductivity and pH measurements together with integrity tests, thermogravimetry analysis (TGA), and leaching analysis are used to confirm the stability of the synthesized geopolymers. Fourier-transform Infrared (FT-IR) spectroscopy is used to follow geopolymerization occurrences. Results for ionic conductivity, pH, and integrity revealed that the synthesized GPs were macroscopically stable. TGA revealed that the main mass losses were ascribable to water dehydration and to water entrapped in the geopolymer networks. Only the GP filled with the powder of the red mud coming from alumina production experienced a mass loss of 23% due to a partial waste degradation. FT-IR showed a red shift in the main Si-O-(Si or Al) absorption band, indicating successful geopolymer network formations. Additionally, most of the GPs filled with the wastes exhibited higher compressive strength (37.8-58.5 MPa) compared to the control (22 MPa). Only the GP filled with the partially stabilized industrial waste had a lower mechanical strength as its structure was highly porous because of gas formation during geopolymerization reactions. Despite the high compressive strength (58.5 MPa) of the GP filled with suction dust waste, the concentration of Sb leached was 25 ppm, which limits its use. Eventually, all samples also demonstrated effective antimicrobial activity against Escherichia coli and Staphylococcus aureus due to the alkaline environment and the presence of metal cations able to react with the bacterial membranes. The findings revealed the possibility of recycling these wastes within several application fields.
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  • 文章类型: Journal Article
    使用低温氩基质隔离红外光谱研究了双(苯)铬(Bz2Cr)和臭氧(O3)的反应,并支持DFT计算。当Bz2Cr和O3共沉积时,它们在基质沉积后发生反应,在431cm-1和792cm-1的红外光谱中产生两个新的突出峰。这些峰在将基质退火至35K时增加,而在λ=254nm的紫外线照射时减少。792cm-1峰的氧18和混合氧16,18同位素位移模式与对称臭氧化物物种的反对称延伸一致。对该反应的许多可能的臭氧化物产物进行了DFT计算。臭氧化氢(H2O3)的形成最适合原始峰和氧18同位素位移模式。能量考虑导致该反应的含铬产物是偶联产物苯-铬-联苯-铬-苯(BzCrBPCrBz)的结论。2Bz2Cr+O3→H2O3+BzCrBPCrBz,ΔEcalc=-52.13kcal/mol。
    Reactions of bis(benzene)chromium (Bz2Cr) and ozone (O3) were studied using low-temperature argon matrix-isolation infrared spectroscopy with supporting DFT calculations. When Bz2Cr and O3 were co-deposited, they reacted upon matrix deposition to produce two new prominent peaks in the infrared spectrum at 431 cm-1 and 792 cm-1. These peaks increased upon annealing the matrix to 35 K and decreased upon UV irradiation at λ = 254 nm. The oxygen-18 and mixed oxygen-16,18 isotopic shift pattern of the peak at 792 cm-1 is consistent with the antisymmetric stretch of a symmetric ozonide species. DFT calculations of many possible ozonide products of this reaction were made. The formation of a hydrogen ozonide (H2O3) best fits the original peaks and the oxygen-18 isotope shift pattern. Energy considerations lead to the conclusion that the chromium-containing product of this reaction is the coupled product benzene-chromium-biphenyl-chromium-benzene (BzCrBPCrBz). 2Bz2Cr+O3→H2O3+BzCrBPCrBz, ∆Ecalc=-52.13kcal/mol.
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  • 文章类型: Journal Article
    与使用局部模式行为的传统分子分析相反,其中局部性程度是通过莫尔斯势能参数的函数给出的,提出了适用于任何分子系统的局部/正态(LN)的新标准。该方法基于对代数正常和局部模式表示之间的联系的分析。表明,只要不保留局部表示中的polyad(量子总数),两种描述都是等效的。局部polyad守恒的约束自然提供了以定量形式分配LN度的标准,在配置空间没有模拟。不同参数之间的相关性揭示了分子的物理性质。还提出了LN度(基于基本原理)与光谱特性之间的明确联系,提出了一种有希望的鉴定同位素混合物的方法。
    In contrast to the traditional analysis of molecules using local mode behavior, where the degree of locality is given through a function in terms of Morse potential parameters, new criteria for locality/normality (LN) suitable for application to any molecular system are proposed. The approach is based on analysis of the connection between the algebraic normal and local mode representations. It is shown that both descriptions are equivalent as long as the polyad (total number of quanta) in the local representation is not conserved. The constraint of a local polyad conservation naturally provides a criterion for assigning an LN degree in quantitative form, without an analogue in configuration space. The correlation between the different parameters reveals the physical properties of molecules. A clear connection between the LN degree (based on the fundamentals) and spectroscopic properties is also presented, suggesting a promising approach for identifying mixtures of isotopologues.
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  • 文章类型: Journal Article
    咖啡豆氧化与酶和非酶褐变有关,所需芳香族化合物的降解,不良风味的发展,增加对微生物腐败的敏感性,和挥发性化合物损失。这项研究调查了在30°C加速储存条件下,在GrainPro®袋中储存0、5、10和20天的自然干燥工艺(DP)和蜂蜜工艺(HP)绿咖啡豆,40°C,和50°C,相对湿度为50%。使用动力学模型来估计绿咖啡豆的保质期。在30°C下,DP记录的耐久性为45.67、29.9和24.92天,40°C,50°C,分别,HP为60.34、38.07和19.22天。进行偏最小二乘(PLS)分析以建立模型,以基于过氧化物(PV)和硫代巴比妥酸反应性物质(TBARS)值预测咖啡的保质期。在利用留一交叉验证(LOOCV)进行预测方面,PLS为TBARS(R2=0.801)提供了更高的精度,而PV较低(R2=0.469)。然而,自动预测显示PV(R2=0.802)和TBARS(R2=0.932)的观测值与预测值具有良好的一致性.根据预测(VIP)分数的可变重要性,ATR-FTIR峰值为3000-2825、2154-2150、1780-1712、1487-2483、1186-1126、1107-1097和1012-949cm-1,被确定为与生咖啡豆保质期的PV和TBARS最相关。ATR-FITR显示出作为一种快速准确的技术来评估与储存过程中咖啡质量损失有关的氧化反应的潜力。
    Coffee bean oxidation is associated with enzymatic and non-enzymatic browning, the degradation of desirable aromatic compounds, the development of undesirable flavors, increased susceptibility to microbial spoilage, and volatile compound losses. This study investigated natural dry process (DP) and honey process (HP) green coffee beans stored in GrainPro® bags for 0, 5, 10, and 20 days under accelerated storage conditions at 30 °C, 40 °C, and 50 °C with relative humidity of 50%. A kinetic model was used to estimate the shelf life of the green coffee beans. DP recorded durability of 45.67, 29.9, and 24.92 days at 30 °C, 40 °C, and 50 °C, respectively, with HP 60.34, 38.07, and 19.22 days. Partial least squares (PLS) analysis was performed to build the models in order to predict the shelf life of coffee based on peroxide (PV) and thiobarbituric acid reactive substances (TBARS) values. In terms of prediction with leave-one-out cross-validation (LOOCV), PLS provided a higher accuracy for TBARS (R2 = 0.801), while PV was lower (R2 = 0.469). However, the auto-prediction showed good agreement among the observed and predicted values in both PV (R2 = 0.802) and TBARS (R2 = 0.932). Based on the variable importance of projection (VIP) scores, the ATR-FTIR peaks as 3000-2825, 2154-2150, 1780-1712, 1487-2483, 1186-1126, 1107-1097, and 1012-949 cm-1 were identified to be the most related to PV and TBARS on green coffee beans shelf life. ATR-FITR showed potential as a fast and accurate technique to evaluate the oxidation reaction that related to the loss of coffee quality during storage.
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  • 文章类型: Case Reports
    经典钾结合剂用于治疗高钾血症,并广泛与胃肠道副作用相关,水晶结肠损伤很少见,但可能致命。在这份报告中,我们描述了一例82岁男性高钾血症和聚苯乙烯磺酸钙晶体相关性结肠坏死的病例.传统上,这种诊断依赖于通过显微镜检查晶体形态和偏振。我们的研究通过结合使用红外光谱对晶体物理特性的分析来增强晶体的识别。这是第一个描述,根据我们的知识,聚苯乙烯磺酸钙的红外光谱。
    Classical potassium binders are used in the treatment of hyperkalemia and are widely associated with gastrointestinal side effects, with crystal colonic injury being rare but potentially fatal. In this report, we describe the case of an 82-year-old male with hyperkalemia and calcium polystyrene sulfonate crystal-associated colonic necrosis. Traditionally, this diagnosis has relied on the examination of crystal morphology and polarization through microscopy. Our study enhances crystal identification by incorporating an analysis of the physical characteristics of the crystals using infrared spectroscopy. This is the first description, to our knowledge, of the calcium polystyrene sulfonate infrared spectrum.
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  • 文章类型: Case Reports
    低磷酸盐症(HPP)是一种罕见的遗传性疾病,与骨矿化不良相关,低血清碱性磷酸酶,高尿焦磷酸盐排泄,和肾钙质沉着症。肾钙化病被认为是由于与高钙血症和高磷酸盐血症相关的过滤负荷增加而发展的。但是这些钙化的组成还不完全清楚。我们报道了有史以来第一个焦磷酸镁(MgPPi)尿路结石,这促使一个12岁男孩的HPP新诊断。结石分析实验室应在其参考库中包括PPi盐的红外光谱,以方便识别这些罕见但临床上重要的结石。
    Hypophosphatasia (HPP) is a rare genetic condition associated with poor bone mineralization, low serum alkaline phosphatase, high urinary pyrophosphate excretion, and nephrocalcinosis. Nephrocalcinosis is thought to develop due to the increased filtered loads associated with hypercalcemia and hyperphosphatemia, but the composition of these calcifications is incompletely understood. We report the first ever magnesium pyrophosphate (MgPPi) urinary stone, which prompted the new diagnosis of HPP in a 12-year-old boy. Stone analysis labs should include infrared spectra of PPi salts in their reference libraries to facilitate identification of these rare but clinically important stones.
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  • 文章类型: Journal Article
    目前,新的功能材料正在被创造,强调其生态方面。基于DNA生物聚合物的材料和装置,环保,因此,从应用的角度来看非常有趣。在本文中,我们介绍了基于质粒DNA(pDNA)和三种具有16个碳原子的脂肪族链的表面活性剂(十六烷基三甲基氯化铵,苄基二甲基十六烷基氯化铵和十六烷基吡啶氯化物)。X射线衍射结果表明质粒DNA复合物中DNA螺旋的局部六边形堆积,类似于基于线性DNA的相应复合物的包装。根据傅里叶变换红外光谱结果,所有三种复合物中的DNA构象被确定为主要是A型。对于所有研究的配合物,通过介电谱揭示的两个弛豫过程与对总电导率的两个不同贡献(微晶部分和晶界)有关。微晶部分(晶粒内部)被解释为极性表面活性剂头基的振荡,并且取决于表面活性剂链的构象。讨论了DNA类型对复合物性质的影响,考虑到我们以前对基于线性DNA的复合物的结果。我们发现DNA的类型对复合物的性质有影响,到目前为止还没有证明。还发现,通过选择频率,pDNA-表面活性剂复合物层可以用作具有可变比电导率的层,从应用的角度来看,这很有趣。
    Currently, new functional materials are being created with a strong emphasis on their ecological aspect. Materials and devices based on DNA biopolymers, being environmentally friendly, are therefore very interesting from the point of view of applications. In this paper, we present the results of research on complexes in the powder form based on plasmid DNA (pDNA) and three surfactants with aliphatic chains containing 16 carbon atoms (cetyltrimethylammonium chloride, benzyldimethylhexadecylammonium chloride and hexadecylpyridinium chloride). The X-ray diffraction results indicate a local hexagonal packing of DNA helices in plasmid DNA complexes, resembling the packing for corresponding complexes based on linear DNA. Based on the Fourier-transform infrared spectroscopy results, the DNA conformation in all three complexes was determined as predominantly of A-type. The two relaxation processes revealed by dielectric spectroscopy for all the studied complexes are connected with two different contributions to total conductivity (crystallite part and grain boundaries). The crystallite part (grain interior) was interpreted as an oscillation of the polar surfactant head groups and is dependent on the conformation of the surfactant chain. The influence of the DNA type on the properties of the complexes is discussed, taking into account our previous results for complexes based on linear DNA. We showed that the type of DNA has an impact on the properties of the complexes, which has not been demonstrated so far. It was also found that the layer of pDNA-surfactant complexes can be used as a layer with variable specific electric conductivity by selecting the frequency, which is interesting from an application point of view.
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  • 文章类型: Journal Article
    热解是使大量农业工业可可残留物增值的一种潜在途径。然而,这个反应的产物,特别是生物油,在许多应用中不具备直接使用所需的质量。因此,这项研究探讨了硫酸铁和硫酸锌作为潜在的催化剂在这些残留物的热解。在这次调查中,生物量,先前研磨并干燥,用不同百分比的硫酸铁和硫酸锌浸渍。采用TG-FTIR技术来确定这些盐对可可壳热解的影响。结果与具有三个伪分量的DAEM模型拟合。已确定,两种盐都会引起可可壳热分解的DTG曲线发生变化。在放出的气体中,化合物,如CO2,H2O,CH4,CO,HCN,和含氧化合物如HCOOH和CH3COOH被检测到。硫酸铁显着影响了控制三种假成分反应的活化能。相反,硫酸锌的存在不会改变与可可壳假成分分解相关的活化能。两种催化剂都会引起放出气体的红外光谱发生变化,这主要表现在对应于CO2、CO、水,和含氧化合物。
    Pyrolysis stands out as one potential route for valorizing abundant agro-industrial cocoa residues. However, the products of this reaction, particularly bio-oil, do not possess the required quality for direct use in many applications. Thus, this study explores the use of iron sulfate and zinc sulfate as potential catalysts in the pyrolysis of these residues. In this investigation, the biomass, previously ground and dried, was impregnated with varying percentages of ferric sulfate and zinc sulfate. The TG-FTIR technique was employed to ascertain the effect of these salts on the pyrolysis of cocoa shell. The results were fitted with the DAEM model with three pseudo-components. It was determined that both salts induced alterations in the DTG profiles of the thermal decomposition of cocoa shell. In the evolved gases, compounds such as CO2, H2O, CH4, CO, HCN, and oxygenated compounds like HCOOH and CH3COOH were detected. Ferric sulfate significantly influenced the activation energies governing the reactions of the three pseudo-components. Conversely, the presence of zinc sulfate did not alter the activation energies associated with the decomposition of cocoa shell pseudo-components. Both catalysts induced alterations in the infrared spectra of the evolved gases, which is primarily evident in the relative intensities of bands corresponding to the stretching vibrations of constituent groups within CO2, CO, water, and oxygenated compounds.
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  • 文章类型: Journal Article
    红外(IR)光谱允许术中,光学脑肿瘤诊断.这里,我们探索了它作为一种转化技术来识别侵袭性脑膜瘤类型,WHO中枢神经系统分级系统和甲基化类别(MC)。
    通过红外光谱成像检查了47个脑膜瘤的冷冻切片,并根据WHO等级或MC比较了不同的分类方法以辨别样品。
    WHO2级和3级之间的IR光谱差异比MC中间和MC恶性之间更明显,虽然相似的光谱范围受到影响。侵袭型脑膜瘤表现出碳水化合物(1024cm-1)和核酸(1080cm-1)的减少带,随着磷脂条带的增加(在1240和1450cm-1)。虽然线性判别分析能够辨别WHO2级和3级脑膜瘤的光谱(AUC0.89),MC失败(AUC0.66)。然而,神经网络分类器根据WHO等级(AUC0.91)和MC(AUC0.83)有效分类,导致测试集的20/23脑膜瘤的正确分类。
    红外光谱被证明能够提取有关脑膜瘤恶性的信息,不仅根据世界卫生组织的等级,也是基于分子肿瘤特征的诊断系统。在未来的临床应用中,医师可以通过考虑分类概率和交叉测量验证来评估分类的优度.这可能会提高整体准确性和临床实用性,增强红外光谱在推进脑膜瘤表征精准医学方面的潜力。
    UNASSIGNED: Infrared (IR) spectroscopy allows intraoperative, optical brain tumor diagnosis. Here, we explored it as a translational technology for the identification of aggressive meningioma types according to both, the WHO CNS grading system and the methylation classes (MC).
    UNASSIGNED: Frozen sections of 47 meningioma were examined by IR spectroscopic imaging and different classification approaches were compared to discern samples according to WHO grade or MC.
    UNASSIGNED: IR spectroscopic differences were more pronounced between WHO grade 2 and 3 than between MC intermediate and MC malignant, although similar spectral ranges were affected. Aggressive types of meningioma exhibited reduced bands of carbohydrates (at 1024 cm-1) and nucleic acids (at 1080 cm-1), along with increased bands of phospholipids (at 1240 and 1450 cm-1). While linear discriminant analysis was able to discern spectra of WHO grade 2 and 3 meningiomas (AUC 0.89), it failed for MC (AUC 0.66). However, neural network classifiers were effective for classification according to both WHO grade (AUC 0.91) and MC (AUC 0.83), resulting in the correct classification of 20/23 meningiomas of the test set.
    UNASSIGNED: IR spectroscopy proved capable of extracting information about the malignancy of meningiomas, not only according to the WHO grade, but also for a diagnostic system based on molecular tumor characteristics. In future clinical use, physicians could assess the goodness of the classification by considering classification probabilities and cross-measurement validation. This might enhance the overall accuracy and clinical utility, reinforcing the potential of IR spectroscopy in advancing precision medicine for meningioma characterization.
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  • 文章类型: Journal Article
    研究了钛(Ti)掺杂对二氧化钒(VO2)光学性能的影响,一种以接近室温的金属到绝缘体转变(MIT)而闻名的材料。通过将Ti掺入到VO2的晶格中,我们的目标是揭示其物理性质的变化,对于增强其在智能设备中的应用至关重要。利用偏振红外显微光谱,我们检查了从远红外到可见光谱范围的不同晶相(导电金红石相和绝缘单斜相M1和M2)中不同Ti浓度(x=0.059,x=0.082和x=0.187)的TixV1-xO2单晶。我们的发现表明,Ti掺杂显着影响声子光谱,引入不归因于纯VO2或TiO2的吸收峰。这在沿晶体生长轴的极化中尤其值得注意,主要在x=0.187样本中。此外,我们证明了电子对金属相中的光学电导率的贡献表现出强烈的各向异性,沿c轴高于a-b平面。这种各向异性,加上随着掺杂的增加,区域中心红外有源声子模式逐渐变宽,强调了掺杂VO2中结构动力学和电子动力学之间复杂的相互作用。我们的结果强调了Ti掺杂在微调VO2的电子和热致变色性能中的潜力,为其在光电设备和技术中的增强应用铺平了道路。
    This study delves into the effects of titanium (Ti) doping on the optical properties of vanadium dioxide (VO2), a material well known for its metal-to-insulator transition (MIT) near room temperature. By incorporating Ti into VO2\'s crystal lattice, we aim to uncover the resultant changes in its physical properties, crucial for enhancing its application in smart devices. Utilizing polarized infrared micro-spectroscopy, we examined TixV1-xO2 single crystals with varying Ti concentrations (x = 0.059, x = 0.082, and x = 0.187) across different crystal phases (the conductive rutile phase and insulating monoclinic phases M1 and M2) from the far-infrared to the visible spectral range. Our findings reveal that Ti doping significantly influences the phononic spectra, introducing absorption peaks not attributed to pure VO2 or TiO2. This is especially notable with polarization along the crystal growth axis, mainly in the x = 0.187 sample. Furthermore, we demonstrate that the electronic contribution to optical conductivity in the metallic phase exhibits strong anisotropy, higher along the c axis than the a-b plane. This anisotropy, coupled with the progressive broadening of the zone center infrared active phonon modes with increasing doping, highlights the complex interplay between structural and electronic dynamics in doped VO2. Our results underscore the potential of Ti doping in fine-tuning VO2\'s electronic and thermochromic properties, paving the way for its enhanced application in optoelectronic devices and technologies.
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