In this study, an extended calculation method for the determination of the water profiles in oil‐treated skin is proposed, which is based on the calculation of the ratio between the Raman band intensities of water (3350‐3550 cm?1) and keratin Amide I at 1650 cm?1. The proposed method is compared with the conventional method based on the ratio of the Raman band intensities of water (3350‐3550 cm?1) and keratin at 2930 cm?1. The conventional method creates artifacts in the depth profiles of the water concentration in oil‐treated skin, showing a lower amount of water in the upper and intermediate layers of the stratum corneum, which is due to the superposition of oil‐ and keratin‐related Raman bands at 2930 cm?1. The proposed extended method shows no artifacts and has the potential to determine the water depth profiles after topical application of formulations on the skin. 相似文献
Colorectal cancer can be prevented if detected early (e.g., precancerous polyps‐adenoma). Endoscopic differential diagnosis of hyperplastic polyps (that have little or no risk of malignant transformation) and adenomas (that have prominent malignant latency) remains an unambiguous clinical challenge. Raman spectroscopy is an optical vibrational technique capable of probing biomolecular changes of tissue associated with neoplastic transformation. This work aims to apply a fiber‐optic simultaneous fingerprint (FP) and high wavenumber (HW) Raman spectroscopy technique for real‐time in vivo assessment of adenomatous polyps during clinical colonoscopy. We have developed a fiber‐optic Raman endoscopic technique capable of simultaneously acquiring both the FP (i.e., 800–1800 cm–1) and HW (i.e., 2800–3600 cm–1) Raman spectra from colorectal tissue subsurface (<200 µm) for real‐time assessment of colorectal carcinogenesis. In vivo FP/HW Raman spectra were acquired from 50 patients with 17 colorectal polyps during clinical colonoscopy. Prominent Raman spectral differences (p < 0.001) were found between hyperplastic (n = 118 spectra), adenoma (n = 184 spectra) that could be attributed to changes in inter‐ and intra‐cellular proteins, lipids, DNA and water structures and conformations. Simultaneous FP/HW Raman endoscopy provides a diagnostic sensitivity of 90.9% and specificity of 83.3% for differentiating adenoma from hyperplastic polyps, which is superior to either the FP or HW Raman technique alone. This study shows that simultaneous FP/HW Raman spectroscopy technique has the potential to be a clinically powerful tool for improving early diagnosis of adenomatous polyps in vivo during colonoscopic examination.
Diet strongly influences the chemistry of vertebrate soft and hard tissues. Bird bone and eggshell mineral preserve reliable records of prey consumption, even beyond the life of the predator, and analyses of hard tissues have usefully reconstructed avian diet. Here, we assess the feasibility of a non‐destructive method for distinguishing krill‐poor from krill‐rich diets in penguins. Krill (Euphausiaceae) are fluoride‐rich, and penguins that consume krill produce fluoride‐rich bones. The chemistry of bone mineral may be elucidated using Raman spectroscopy without recourse to specialised sample preparation. Published data from the diet of six penguin species were compared to a fluoride‐informative spectral band (phosphate symmetric stretch, ν1‐PO43?) in the Raman spectra of penguin humeri. Penguins that consume abundant krill (e.g. Adélie and emperor) have ν1‐PO43?‐band positions higher than 963 cm?1, whereas penguins that primarily eat teleost fish or cephalopods (e.g. Fiordland crested, Humboldt, little blue and yellow‐eyed) have ν1‐PO43?‐band positions lower than 963 cm?1. A krill‐rich diet can therefore be determined from the Raman spectra of penguin bones. Raman spectroscopy could be a useful supplement to existing diet analysis techniques. 相似文献
The aim of this study was to determine whether Raman spectroscopy combined with chemometric analysis can be applied to interrogate biofluids (plasma, serum, saliva and urine) towards detecting oesophageal stages through to oesophageal adenocarcinoma [normal/squamous epithelium, inflammatory, Barrett's, low‐grade dysplasia, high‐grade dysplasia and oesophageal adenocarcinoma (OAC)]. The chemometric analysis of the spectral data was performed using principal component analysis, successive projections algorithm or genetic algorithm (GA) followed by quadratic discriminant analysis (QDA). The genetic algorithm quadratic discriminant analysis (GA‐QDA) model using a few selected wavenumbers for saliva and urine samples achieved 100% classification for all classes. For plasma and serum, the GA‐QDA model achieved excellent accuracy in all oesophageal stages (>90%). The main GA‐QDA features responsible for sample discrimination were: 1012 cm?1 (C─O stretching of ribose), 1336 cm?1 (Amide III and CH2 wagging vibrations from glycine backbone), 1450 cm?1 (methylene deformation) and 1660 cm?1 (Amide I). The results of this study are promising and support the concept that Raman on biofluids may become a useful and objective diagnostic tool to identify oesophageal disease stages from squamous epithelium to OAC. 相似文献
In this study, the transition process of the helix‐sense inversion of poly(β‐phenethyl‐L‐aspartate) was investigated by Raman scattering and 2‐dimensional correlation spectroscopy. Temperature‐dependent Raman spectra were obtained during the helix‐sense inversion. The results of 2‐dimensional correlation analysis in the spectral regions of 1600‐1800 and 3200‐3400 cm?1 showed that the intensity changes of the side‐chain ester C═O stretching bands occurred prior to those of amide A and amide I bands in the unwinding process of αR‐helix on heating. The sequential order of the intensity changes for amide A, amide I, and the side‐chain ester C═O stretching bands during the inversion process was determined. It was found that the conformation change of the side chain occurred prior to that of the main chain for the αR‐helix on heating. Thus, we concluded that the transformation of the backbone chain from right‐handed to left‐handed is triggered by the conformational change of the side chains. 相似文献
Here, a simple active materials synthesis method is presented that boosts electrode performance and utilizes a facile screen‐printing technique to prepare scalable patterned flexible supercapacitors based on manganese hexacyanoferrate‐manganese oxide and electrochemically reduced graphene oxide electrode materials (MnHCF‐MnOx/ErGO). A very simple in situ self‐reaction method is developed to introduce MnOx pseudocapacitor material into the MnHCF system by using NH4F. This MnHCF‐MnOx electrode materials can deliver excellent capacitance of 467 F g?1 at a current density of 1 A g?1, which is a 2.4 times capacitance increase compared to MnHCF. In addition a printed, patterned, flexible MnHCF‐MnOx/ErGO supercapacitor is fabricated, showing a remarkable areal capacitance of 16.8 mF cm?2 and considerable energy and power density of 0.5 mWh cm?2 and 0.0023 mW cm?2, respectively. Furthermore, the printed patterned flexible supercapacitors also exhibit exceptional flexibility, and the capacitance remains stable, even while bending to various angles (60°, 90°, and 180°) and for 100 cycles. The flexible supercapacitor arrays integrated by multiple prepared single supercapacitors can power various LEDs even in the bent states. This approach offers promising opportunities for the development of printable energy storage materials and devices with high energy density, large scalability, and excellent flexibility. 相似文献
The aim of this study was to determine the resistance mechanisms of chili induced by the Bacillus subtilis strain D604 using synchrotron FTIR microspectroscopy (SR-FTIR). In this study, the strain D604 reduced anthracnose disease severity in chili plants by approximately 31.10%. The SR-FTIR spectral changes from the epidermis and mesophyll leaf tissue revealed higher integral areas for the C=O ester from lipids, lignin, or pectin (1770–1700?cm?1) as well as polysaccharides (1200–900?cm?1) in the treated samples of D606 and distilled water and then challenge inoculation with chili anthracnose pathogen, Colletotrichum acutatum. The secondary structure of the Amide I protein failed to convert from alpha helices (centered at 1650?cm?1) to beta sheets (centered at 1600?cm?1) in the mesophyll of samples not treated with D604. This study suggested that the strain D604 induced resistance against anthracnose pathogen in chili by inducing cellular changes related to defense compounds involved in plant defense mechanism. 相似文献
The achievement of effective alkaline hydrogen production from water electrolysis is an active field of research. Herein, an integrated electrode composed of crystalline Ni(OH)2 and amorphous NiMoOx is fabricated onto nickel foam (denoted as Ni(OH)2–NiMoOx/NF). The hydrogen evolution reaction (HER) kinetics are optimized along with phase transformation process during soaking operation. An overpotential of 36 mV to drive 10 mA cm?2 along with the low Tafel slope of 38 mV dec?1 reveals the catalyst's excellent HER performance and a Heyrovsky‐step‐controlled HER mechanism. When assembled into a urea‐assisted water electrolyzer, a voltage of 1.42 V can reach 10 mA cm?2. Further experiments and Fourier transform infrared spectroscopy (FTIR) results illustrate the synergy effect between crystalline and amorphous areas and the optimized water dissociation step. Crystalline Ni(OH)2 serves as the scissor for water dissociation in an alkali environment to produce H*, while the amorphous NiMoOx layer serves as the location for H* adsorption and H2 desorption. 相似文献
We report the resonance Raman spectra in the frequency range 300–1800 cm?1 of Fe (III)-ovotransferrin and Fe (III)-human serum transferrin in aqueous solution at about 10?4M protein concentration. This is the first observation of resonance Raman scattering ascribable to amino acid ligand vibrational modes of a nonheme iron protein. The resonance Raman spectra of the transferrins are similar except that the resonance band near 1270 cm?1 is shifted to a higher frequency for Fe(III)-human serum transferrin than that for Fe(III)-ovotransferrin. The resonance Raman bands observed near 1170, 1270, 1500 and 1600 cm?1 may reflect resonance enhancement of p-hydroxy-phenyl frequencies of tyrosine residues and/or imidazolium frequencies of histidine residues. 相似文献
Iodine‐doped n‐type SnSe polycrystalline by melting and hot pressing is prepared. The prepared material is anisotropic with a peak ZT of ≈0.8 at about 773 K measured along the hot pressing direction. This is the first report on thermoelectric properties of n‐type Sn chalcogenide alloys. With increasing content of iodine, the carrier concentration changed from 2.3 × 1017 cm?3 (p‐type) to 5.0 × 1015 cm?3 (n‐type) then to 2.0 × 1017 cm?3 (n‐type). The decent ZT is mainly attributed to the intrinsically low thermal conductivity due to the high anharmonicity of the chemical bonds like those in p‐type SnSe. By alloying with 10 at% SnS, even lower thermal conductivity and an enhanced Seebeck coefficient were achieved, leading to an increased ZT of ≈1.0 at about 773 K measured also along the hot pressing direction. 相似文献
In the present study, Fourier‐transform infrared spectroscopy (FTIR) is investigated as a method to measure connective tissue components that are important for the quality of Atlantic cod filets (Gadus morhua L.). The Atlantic cod used in this study originated from a feeding trial, which found that fish fed a high starch diet contained relative more collagen type I, while fish fed a low starch (LS) diet contained relative more glycosaminoglycans (GAGs) in the connective tissue. FTIR spectra of pure commercial collagen type I and GAGs were acquired to identify spectral markers and compare them with FTIR spectra and images from connective tissue. Using principal component analysis, high and LS diets were separated due to collagen type I in the spectral region 1800 to 800 cm?1. The spatial distribution of collagen type I and GAGs were further investigated by FTIR imaging in combination with immunohistochemistry. Pixel‐wise correlation images were calculated between preprocessed connective tissue images and preprocessed pure components spectra of collagen type I and GAGs, respectively. For collagen, the FTIR images reveal a collagen distribution that closely resembles the collagen distribution as imaged by immunohistochemistry. For GAGs, the concentration is very low. Still, the FTIR images detect the most GAGs rich regions. 相似文献
I.r. spectra in the “carbonyl region” (1800-1400 cm?1) have been obtained for aqueous solutions of a number of glycosaminoglycans and model compounds. In D2O solution, the uronic carboxylate and acetamido groups absorb at characteristic frequencies (νasCOO?, 1605 ±5; ν5COO?, 1420 ±5; Amide I, 1623 ±3; and Amide II, 1480 ±2 cm?1). In acidic (m DCl) solution, the amide bands remain substantially unmodified, whereas those of the carboxylate anion disappear and are replaced by a single band due to the undissociated carboxyl (νCOOH, 1723 ±3 cm?1). These bands can be used for quantitative evaluation of the uronic acid and acetamidodeoxyhexose moieties of glycosaminoglycans, using either standard polysaccharides or the corresponding monosaccharides as reference compounds. For D2O solutions, the absorbances of the carboxylate and acetamido groups have been measured by graphical extrapolation of the corresponding most-intense bands (νasCOO? and Amide I). In DCl, the two analytical bands (νCOOH and Amide I) are well-resolved, and analyses have been performed directly from the absorbances recorded. I.r. data for the uronic acid and 2-acetamido-2-deoxyhexose content of various reference samples of glycosaminoglycans are in reasonable agreement with those expected from the “established” structures, as well as with those obtained by colorimetric and conductimetric methods. When sodium d-glucuronate was used as the reference standard, the i.r. data gave relatively low values for the uronic acid content of heparin. The apparent acid dissociation constants of chondroitin 4-sulfate and heparin were estimated from the absorbance of νCOO? and/or the νCOOH bands at different pH (pD) values. 相似文献