Journal of Raman Spectroscopy最新文献

{"title":"Alteration in the Raman spectra of characteristic rock-forming silicate mixtures due to micrometeorite bombardment","authors":"Iris Weber,&nbsp;Sergey G. Pavlov,&nbsp;Ute Böttger,&nbsp;Maximilian P. Reitze","doi":"10.1002/jrs.6676","DOIUrl":"10.1002/jrs.6676","url":null,"abstract":"<p>Innovative techniques are required for the in situ investigation of the surfaces of planetary bodies when landings are planned. Raman spectroscopy turned out as an excellent tool for fast mineralogical analyses on space missions. Contribution from a photoluminescence signal is not unexpected and is likely to be even more pronounced on celestial surfaces with a dilute or absent atmosphere exposed to strong space weathering, for example, micrometeorite bombardment. Such signals were found, for example, in Raman analysis of the probes from sample-return missions. While photoluminescence is generally considered as an accompanying undesired product in the Raman spectral measurement, our studies show that some analytical information can be derived from this signal, and even more, due to the specific correlation of luminescence intensity with space weathering products. Therefore, we investigate the Raman spectra alteration of characteristic rock-forming mineral mixtures (olivine, pyroxene and plagioclase) by micrometeorite bombardment, which is simulated by nanosecond-pulse laser irradiation. The changes in the minerals are strongly dependent on the composition and structure. They range from disappearing changes in the minerals with simple chemistry and structure to complete amorphization of minerals with relatively low melting enthalpy. With Raman spectroscopy, we found out that the photoluminescence signals show resonant or anti-resonant changes to specific mineral phases and amorphization. Furthermore, ablation-induced iron nanoparticles of minerals containing Fe are detectable by Raman spectroscopy due to their alteration into iron oxides. Trapped volatiles in the matrices are analysed due to the formation of the compounds containing them. This broad spectrum of results indicating specific change phenomena due to space weathering can be effectively used for in situ Raman analysis in planetary missions.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 8","pages":"901-913"},"PeriodicalIF":2.4,"publicationDate":"2024-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jrs.6676","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140939897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphological effect on Core@shell AuAg nanoparticles for detecting p-aminothiophenol dimerization by surface-enhanced Raman spectroscopy","authors":"María de la Cabeza Fernández,&nbsp;Alexis Alvear-Jiménez,&nbsp;Arantxa Forte-Castro,&nbsp;Rafael Contreras-Cáceres,&nbsp;María Rosa López-Ramírez","doi":"10.1002/jrs.6677","DOIUrl":"10.1002/jrs.6677","url":null,"abstract":"<p>A series of non-spherical metallic Au and bimetallic core@shell AuAg nanoparticles (NPs) have been synthesized for SERS improvements. The bimetallic core@shell AuAg NPs were obtained through a controlled overgrowth of an Ag shell onto the surface of two types of non-spherical Au NPs, used as seeds, Au nanooctaheda (Au NOc) and Au nanotriangles (Au NTs). This Ag overgrowth was able to produce bimetallic core@shell structures such as nanocubes and nanopyramids, respectively. Transmission electron microscopy (TEM) was used to determine the particle size and particle morphology for metallic and bimetallic NPs, and energy-dispersive X-ray (EDX) elemental mapping analysis confirmed the core@shell structure of the bimetallic NPs. The plasmonic absorption bands exhibited for each nanosystem were observed by UV–vis spectroscopy. The concentration of Au and Ag in the bimetallic systems was determined by inductively coupled plasma mass spectrometry (ICP-MS). After synthesis and characterization, p-aminothiophenol (PATP) was used as a model analyte to investigate the surface-enhanced Raman spectroscopy (SERS) capabilities of the synthesized metallic and bimetallic nanosystems. In PATP, a dimerization reaction to 4,4′-dimercaptoazobenzene (DMAB) is produced when it is adsorbed onto the surface of certain noble metals. This SERS analysis was performed at 10⁻⁴ M of PATP and by using two different laser wavelengths (532 and 785 nm) in all cases. In this context, we were able to detect the dimerization reaction of PATP to DMAB only for the bimetallic structures and under the 532 nm laser line. Moreover, we have found that the dimerization capacity also depends on the nanoparticle morphology.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 8","pages":"855-869"},"PeriodicalIF":2.4,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140942484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative analysis model based on surface-enhanced Raman spectroscopy of malachite green adsorbed on gold nanoparticles film substrates","authors":"Hui-Mei Huang,&nbsp;Yu-Bei Zhang,&nbsp;Ting-Wei Weng,&nbsp;He-Tian Qiao,&nbsp;Xiao-Tian Yuan,&nbsp;Zubia Sajid,&nbsp;De-Yin Wu,&nbsp;Zhong-Qun Tian","doi":"10.1002/jrs.6678","DOIUrl":"10.1002/jrs.6678","url":null,"abstract":"<p>In order to investigate the adsorption process of malachite green (MG) on gold nanoparticles, a simple gold nanoparticles-assembled film was prepared as a substrate of surface-enhanced Raman spectroscopy (SERS), and it was soaked in MG solutions of different concentrations. The kinetic adsorption process was investigated by SERS method and density functional theoretical calculations. When saturated adsorption was achieved, the relationship between the characteristic SERS band signal intensity and the logarithm of solution concentration of MG was consistent with Temkin adsorption isotherm model, where the <i>R</i>² value was greater than 0.995, and the linear range was 1 × 10⁻³–1 × 10⁻⁷ M. Finally, a SERS quantitative analysis model of the relationship between the adsorption properties of surface species and the bulk concentration was established. According to the electrostatic interaction and co-adsorption, we proposed the surface adsorption configurations and adsorption process of MG on the nanostructured gold films.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 8","pages":"870-881"},"PeriodicalIF":2.4,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140939898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dual coherent anti-Stokes Raman scattering microscopy across the vibrational spectrum enabled by single pump optically synchronised oscillators and spectral focusing","authors":"Dominykas Gudavičius,&nbsp;Lukas Kontenis,&nbsp;Wolfgang Langbein","doi":"10.1002/jrs.6671","DOIUrl":"10.1002/jrs.6671","url":null,"abstract":"<p>Coherent anti-Stokes Raman scattering microscopy probing two independently selectable vibrational frequencies across the vibrational spectrum is demonstrated. A one-box femtosecond laser source provides three synchronised 100–200 fs pulses of 77 MHz repetition rate, one at a fixed wavelength of 1025 nm from an Yb oscillator and two independently tuneable ones, over 680–960 nm and 960–1300 nm, respectively, from two optically synchronised parametric oscillators. Combined with spectral focusing, the source allows addressing the fingerprint, cell silent and C–H stretch vibrational regions simultaneously, avoiding the motion artefacts seen in sequential imaging. We demonstrate the microscopy method on water/heavy water/oil emulsions, plastic beads and deuterated lipids inside cells.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 7","pages":"744-752"},"PeriodicalIF":2.4,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jrs.6671","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140939896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Raman spectroscopy, phase transitions, microstructures, and mechano-luminescence in Ca-Sr feldspars (CaAl2Si2O8-SrAl2Si2O8)","authors":"Nadia Curetti,&nbsp;Davide Bernasconi,&nbsp;Mario Tribaudino","doi":"10.1002/jrs.6675","DOIUrl":"10.1002/jrs.6675","url":null,"abstract":"&lt;p&gt;The Raman spectra of Ca&lt;sub&gt;1-x&lt;/sub&gt;Sr&lt;sub&gt;x&lt;/sub&gt;Al&lt;sub&gt;2&lt;/sub&gt;Si&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;8&lt;/sub&gt; (0 ≤ x ≤ 1) feldspars have been measured, to investigate at a short-range scale the effect of changing composition on the &lt;i&gt;P&lt;/i&gt;\u0000 &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mover&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;mo&gt;¯&lt;/mo&gt;\u0000 &lt;/mover&gt;&lt;/math&gt; ➔ &lt;i&gt;I&lt;/i&gt;\u0000 &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mover&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;mo&gt;¯&lt;/mo&gt;\u0000 &lt;/mover&gt;&lt;/math&gt; and &lt;i&gt;I&lt;/i&gt;\u0000 &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mover&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;mo&gt;¯&lt;/mo&gt;\u0000 &lt;/mover&gt;&lt;/math&gt; ➔ &lt;i&gt;I&lt;/i&gt;2/&lt;i&gt;c&lt;/i&gt; phase transitions and how phase transitions affect the mechano-luminescence found in these feldspars. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were done on the same samples, to pinpoint the transitions, by the analysis of selected area diffraction patterns (SAED) and of the spontaneous strain. Natural anorthite (CaAl&lt;sub&gt;2&lt;/sub&gt;Si&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;8&lt;/sub&gt;) shows a large number of well-resolved peaks, together with sharp h + k even, l odd diffractions (&lt;i&gt;c&lt;/i&gt;-type) in SAED patterns, indicative of a &lt;i&gt;P&lt;/i&gt;\u0000 &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mover&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;mo&gt;¯&lt;/mo&gt;\u0000 &lt;/mover&gt;&lt;/math&gt; symmetry. In synthetic anorthite, the Raman spectrum is similar to that of natural anorthite, but the peaks are broader, and c-type reflections are elongated. As Sr increases, the &lt;i&gt;c&lt;/i&gt;-type reflections become more diffuse and elongated, as the Raman peaks do. At x &gt; 0.6, new peaks appear in Raman spectra, and other peaks show a change in their wavenumber. Moreover, the &lt;i&gt;c&lt;/i&gt;-type reflections disappear completely, and the lattice becomes &lt;i&gt;I&lt;/i&gt;-centred. Between x ~ 0.6 and x = 0.86(3), the XRD patterns prompt for a triclinic structure, with S.G. &lt;i&gt;I&lt;/i&gt;\u0000 &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mover&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;mo&gt;¯&lt;/mo&gt;\u0000 &lt;/mover&gt;&lt;/math&gt;. The transition to the monoclinic &lt;i&gt;I&lt;/i&gt;2/&lt;i&gt;c&lt;/i&gt; structure is well constrained by the ferroelastic strain, whereas the Raman spectra are more similar between the monoclinic and triclinic &lt;i&gt;I&lt;/i&gt;\u0000 &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mover&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;mo&gt;¯&lt;/mo&gt;\u0000 &lt;/mover&gt;&lt;/math&gt; and &lt;i&gt;I&lt;/i&gt;2/&lt;i&gt;c&lt;/i&gt; than between &lt;i&gt;I&lt;/i&gt;\u0000 &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mover&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;mo&gt;¯&lt;/mo&gt;\u0000 &lt;/mover&gt;&lt;/math&gt; and &lt;i&gt;P&lt;/i&gt;\u0000 &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mover&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;mo&gt;¯&lt;/mo&gt;\u0000 &lt;/mover&gt;&lt;/math&gt;. The absence of mechano-luminescence in triclinic &lt;i&gt;I&lt;/i&gt;\u0000 &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mover&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;mo&gt;¯&lt;/mo&gt;\u0000 &lt;/mover&gt;&lt;/math&gt; compositions suggests that this property is enhanced in local &lt;i&gt;P&lt;/i&gt;\u0000 &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mover&gt;\u0000 &lt;mn","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 7","pages":"833-848"},"PeriodicalIF":2.4,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140942436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Raman spectroscopy-based molecularly imprinted polymer sensor for sensitive detection of lysophosphatidic acid in serum","authors":"Nazia Tarannum,&nbsp;Deepak Kumar,&nbsp;Akanksha Yadav,&nbsp;Anil K. Yadav","doi":"10.1002/jrs.6673","DOIUrl":"10.1002/jrs.6673","url":null,"abstract":"<p>Lysophosphatidic acid (LPA) has significant potential as a biomarker for diagnosis of ovarian cancer in female patients because it is present throughout all phases of the illness. Regrettably, there is not a clinically useful test for this biomarker yet. In this work, an ultra-detection of LPA molecule by Raman spectroscopy-based molecularly imprinted polymer (MIP) in serum samples is reported. β-CD was synthesized to facilitate the collection of Raman spectroscopy and combined with MIP to denote it as β-CD-MIP for the adsorption of LPA with high sensitivity and selectivity. Linear regression model in serum samples shows peaks at 1100 and 1116 cm⁻¹, respectively. A satisfactory linear fit was seen with LPA concentration log I = 3.7 log C + 1255.74 and with spiked serum log I = 4.6 log C + 327.22, respectively. The literature survey suggests the threshold LPA level in healthy person is 1.50 μM/L whereas the LPA level rises in patients with benign ovarian cancer tumor as 7.90 μM/L. This LPA level rises to 16.99 μM/L in ovarian cancer patients. On the basis of the band intensity, the limit of detection of the β-CD-MIP sensor for LPA was recorded as 0.003 μM/L. The binding constant of β-CD-MIP for LPA in serum was 0.031–0.003 μM/L, respectively. β-CD-MIP gel was optimized, characterized, and successfully applied on spiked serum samples. The findings of this research show that this substrate has a lot of potential for ultradetection of trace amounts of LPA molecule from the serum samples. The MIP sensor is robust, recyclable, efficient, and selective.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 7","pages":"809-818"},"PeriodicalIF":2.4,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140942309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comprehensive analysis of metabolomics and lipidomics in areca nut mediated oral submucous fibrosis progression through LCMS and Raman spectroscopy","authors":"Tarun Prakash Verma,&nbsp;Sonali Adhikari,&nbsp;Siddharth Singh,&nbsp;Chanchal Rani,&nbsp;Rajesh Kumar,&nbsp;Hem Chandra Jha","doi":"10.1002/jrs.6679","DOIUrl":"10.1002/jrs.6679","url":null,"abstract":"<p>Habitual consumption of areca/betel nut in Southeast Asia has been associated with oral submucous fibrosis (OSMF) and its malignant transformation to oral squamous cell carcinoma. The current study aimed to assess the molecular alterations in fibroblast cell lines after treatment with areca nut. Areca nut extract (ANE) was prepared and characterized for its active ingredient, arecoline. ANE-treated cells were subjected to cell viability, proliferation, migration, morphologic changes, and transcript of OSMF genes (<i>col1a1</i>, <i>col1a2</i>, <i>hsp47</i>, <i>timp1</i>, <i>timp2</i>, <i>timp3</i>, and <i>timp4</i>). Further, liquid chromatography–mass spectrometry (LCMS) of cell lysate and Raman microspectroscopy (RMS) of fixed cells were performed for metabolomics/lipidomics and biomolecular alterations in the nucleus and periphery of ANE-treated cells. We compared and integrated the data from both techniques and observed that the cells treated with ANE mimicked OSMF and could be used as an in vitro model. LCMS showed a significant alteration in 17 metabolites and 165 lipid molecules in the cells treated with ANE. Further, 40 molecules in the nucleus and 29 in the periphery were found to be altered in these cells when subjected to RMS. Molecules associated with pathways such as the transfer of acetyl groups into mitochondria, amino sugar metabolism, and the Warburg effect were modulated the most upon ANE treatment. Acetyl CoA was found to be common in most of the altered pathways. Besides, the pathways affecting carbohydrate metabolism were also altered significantly. Targeting these molecules and pathways can help to prevent the malignant transformation of OSMF.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 7","pages":"797-808"},"PeriodicalIF":2.4,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140942486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The pH effects on thermal amyloid fibrillation kinetics of hen egg-white lysozyme using new normalization factor for Raman spectroscopy","authors":"Dongxiao Liu,&nbsp;Ning Chen,&nbsp;Tianle Zhang,&nbsp;Xiaoguo Zhou,&nbsp;Shilin Liu","doi":"10.1002/jrs.6674","DOIUrl":"10.1002/jrs.6674","url":null,"abstract":"<p>Amyloid fibrillation kinetics of proteins associated with neurodegenerative diseases has been extensively studied using Raman spectroscopy. The normalization factor for the spectra is crucial for obtaining correct kinetics of Raman indicators, especially vibrational band intensities. Here, we compared the concentration dependences between the absorption at 280 nm in UV–vis spectroscopy and the phenylalanine (Phe) Raman band intensity at 1003 cm⁻¹ in amyloid fibrillation kinetics of lysozyme. The former exhibits better performance as normalization factor. Using this new normalization factor, the effect of <i>p</i>H value on the transformation of hen egg-white lysozyme (HEWL) tertiary and secondary structures was studied subsequently. With increasing acidity, the unfolding of tertiary structures and the transformation of secondary structures are significantly accelerated. Notably, the populations of various secondary structures in the final state remain in the <i>p</i>H &lt; 2.0 solutions, indicating that the branching ratios of “on-pathway” to amyloid fibrils and “off-pathway” to gel-like aggregates are independent on the <i>p</i>H value in the range of 1.1–1.9.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 7","pages":"787-796"},"PeriodicalIF":2.4,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140839167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"π-π stacking interactions mediate molecular recognition between arginine and tryptophan containing peptides derived from human islet polypeptide","authors":"J. Vedad,&nbsp;M. Bilog,&nbsp;A. Chamorro,&nbsp;A. A. Profit,&nbsp;R. Z. B. Desamero","doi":"10.1002/jrs.6672","DOIUrl":"10.1002/jrs.6672","url":null,"abstract":"<p>Cation-π interactions, often found in protein assemblies, are characterized by favorable electrostatic interactions between an aromatic π-electron surface and a positively charged species. There are evidences that reveal the importance of cation-π interactions between arginine and aromatic residues in protein structure and function. In this paper, the effect of cation-π interactions on the aggregation propensity of peptides derived from human islet polypeptide (hIAPP) was explored using UV resonance Raman and fluorescence spectroscopy. By employing an analog of hIAPP_22–29 in which Phe-23 is replaced with tryptophan (NWGAILSS), we were able to demonstrate an increase in the amyloidogenic propensity of this mutant in the presence of Zn²⁺ that is attributable to cation-π interactions. In contrast, no cation-π interactions were observed when the cationic F23R analog of hIAPP_22–29 (NRGAILSS) was allowed to interact with NWGAILSS. From these observations, it was surmised that in these peptides, the dominant interaction between arginine and tryptophan involves the π-cloud of the guanidino group and the indole ring, not cation-π interactions. The spectroscopic data, supported by density functional theory-based simulation results, suggest that arginine-tryptophan interaction involves π-π stacking where the guanidino group is oriented parallel to the indole ring. These hydrophobic interactions, coupled with the hydrotropic effect of the guanidine functionality of arginine, led to a delay in the aggregation kinetics of NWGAILSS. These unique interactions were further exploited to design a peptide inhibitor of full-length amylin self-assembly.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 7","pages":"774-786"},"PeriodicalIF":2.4,"publicationDate":"2024-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140839258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of XC functionals and dispersion corrections on the DFT-computed structural and vibrational properties of SrCl2–NaCl and ZrF4–LiF","authors":"Amir M. Mofrad,&nbsp;Matthew S. Christian,&nbsp;Juliano Schorne-Pinto,&nbsp;Jorge P. S. Palma,&nbsp;Theodore M. Besmann","doi":"10.1002/jrs.6670","DOIUrl":"10.1002/jrs.6670","url":null,"abstract":"<p>Density functional theory (DFT) calculations were performed to examine the impact of exchange–correlation (XC) functionals and van der Waals corrections (specifically the D3 method) on the structural and vibrational properties of the SrCl₂–NaCl and ZrF₄–LiF salt systems. Multiple XC functionals, including the local density approximation (LDA), the generalized gradient approximation using the Perdew–Burke–Ernzerhof (PBE) model, and its modified form suitable for solids (PBEsol), the dispersion-corrected PBE-D3 and PBEsol-D3, were considered. Of these functionals, LDA was found to exhibit the highest degree of error, while PBEsol and PBE-D3 displayed the least error. Underestimated lattice parameters compared with experimental values were observed to result in higher force constants, leading to an overprediction of vibrational frequencies. Conversely, an overestimation of lattice parameters was associated with lower vibrational frequencies. The methodology presented in this study yielded results that are in good agreement with experiment, irrespective of the method (finite differences vs. density functional perturbation theory) employed for calculating infrared and Raman spectra. It was further demonstrated that for alkali halides with weak Raman scattering, utilizing a supercell constructed from primitive cells better predicts Raman features than does the use of conventional cells.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 7","pages":"819-832"},"PeriodicalIF":2.4,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jrs.6670","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140591113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}