Transcutaneous in vivo Raman spectroscopy: Detection of age-related changes in mouse breast

The risk of female breast cancer increases as age progresses. This can be explained by Pike's model, which suggests that the process of aging in breast is not uniform. ‘Breast ageing’ is most rapid during menarche, slows with each pregnancy, slows further during perimenopause, and is least after the menopause. In this study, the feasibility of using transcutaneous in vivo Raman spectroscopy to detect age-related changes in mouse breast and its effect on tumor detection were explored. Spectra acquired transcutaneously from breast of 2 (menarche), 4–6 (mid reproductive phase), 10–12 (perimenopause), 13–15 month (menopause) old mice and frank breast tumors were analyzed using principal component-linear discriminant analysis (PC-LDA). A classification efficiency of ∼80% was achieved for different age groups. Further, it was observed that the number of misclassifications among age groups increase as age progresses. For example, 3% spectra from menarche misclassify with other age groups, while 19–28% from mid-reproductive, perimenopause and menopause misclassify with each other. Misclassifications between groups indicate homogeneity in tissues. Thus, results suggest that menarche breast is biochemically distinct while breast during mid-reproductive, perimenopause and menopause is relatively homogenous. This probably indicates that the rate of aging is rapid during menarche, but slows down during other phases. Thus, spectroscopic data correlate with Pike's model. Although sensitive to age-related changes, RS could classify tumors with 95% efficiency. Overall, results suggest possibility of distinguishing age-related changes using RS without affecting ability to classify tumors.     

Age-related changes of aqueous protein profiles in rat fast and slow twitch skeletal muscles

Two-dimensional electrophoresis was used to generate the aqueous protein expression patterns of rat extensor digitorum longus muscle (EDL, fast twitch muscle) and solues muscle (SOL, slow twitch muscle) of different ages. Two specific protein spots, S1 and S3, were identified from EDL muscles at the ages of 12 and 18 months onward respectively. In the EDL muscles of aged rat (24 months) after intensive exercise training, S3 was still detected while S1 disappeared. In addition, diaphragm muscle (DIA, fast twitch muscle), which retains physically active throughout the life span, was used as nondisuse control. The results showed that the expressions of S1 and S3 in 24-month DIA muscle were identical with the trained aged EDL muscle. It is suggested that exercise might delay the onset of S1 expression. However, the expression of S3 over age seemed to be progressive and exercise independent. Another protein spot, S2 was identified to express only in young EDL and SOL muscles, but its expression decreased over age. Furthermore, exercise has no effect on S2 expression since S2 could not be detected in aged DIA as well as trained aged EDL and SOL muscles. These results indicated that aqueous protein expression patterns of skeletal muscle undergo changes during aging. Some of these changes such as S2 and S3 appear progressively, and some such as S1 could be delayed by exercise. S3 was identified as ubiquitin, which might play an important role in protein degradation during skeletal muscle aging process.     

Effect of antioxidants on aging of the chloroprene rubber/butadiene rubber (CR/BR) blends

Thermal degradation of blends containing chloroprene rubber (CR) and butadiene rubber (BR) cross-linked with copper(II) oxide (CuO) with the addition of anti-aging substance ((N-(1.3-dimethylbutyl)-N-phenyl-p-phenylenediamine (6PPD), polymerized 2.2.4-trimethyl-1.2-dihydroquinoline (TMQ), or 2-mercaptobenzimidazole (MBI)) under high temperature was investigated using a Fourier Transform Infrared spectroscopy (FTIR) spectroscopy and color measurement. Additionally, changes in mechanical properties (such as tensile strength, elongation at break, hardness, tear resistance) causes by aging factors have also been investigated. The results indicated that the 6PPD and the MBI provided better protection of the CR/BR/CuO vulcanizates against degradation at elevated temperature than the TMQ. As a result of thermo-oxidative aging, in an infrared spectrum, a peak assigned to stretching vibration of carbonyl groups was observed. Differences in protection against thermo-oxidative aging by the anti-aging substance are caused by their different structure, consequently, by the differences in their protection mechanism.     

Metabolomic analysis of amino acids and organic acids in aging mouse eyes using gas chromatography–tandem mass spectrometry

This is a metabolomics study for monitoring altered amino acid (AA) and organic acid (OA) metabolism of in eyes from aging an mouse model at 8 and 18 weeks and 18 months. Simultaneous metabolic profiling analysis of OAs and AAs was performed as ethoxycarbonyl/methoxime/tert-butyldimethylsilyl derivatives by gas chromatography–tandem mass spectrometry. A total of 42 metabolites—24 AAs and 18 OAs—were determined and their composition values were normalized to the corresponding mean values of 8-week-old mice as the control group. Then their normalized values were plotted as star graphs, which were distorted and readily distinguishable for each age-related group. Among the 42 metabolites, 18 AAs and 11 OAs were age dependent and significantly different (p < 0.05). Principal component analysis and partial least squares discriminant analysis showed unclear separation between 8- and 18-week-old mice but clear separation between these and 18-month-old mice. In particular, the variable importance in projection scores of 4-hydroxyproline, cis-aconitic acid, glycine, isocitric acid, leucine, pipecolic acid and lysine from partial least-squares–discriminant analysis were higher than 1.3. A heatmap for the classification and visualization of 42 metabolites showed differences in metabolite changes with aging. Altered AA and OA profiles were monitored, which may explain the metabolic disturbance of AA and OA. These findings are related to mitochondrial dysfunctions related to energy metabolism and the impaired antioxidant system in the aging eye. Therefore, the present metabolomics results of the association between physiological states and altered metabolism of AA and OA will be useful for understanding the aging eye and related diseases.     

环氧化天然橡胶凝胶溶胶的热老化性能

环氧化天然橡胶凝胶溶胶的热老化性能;红外差谱     

Simultaneous measurement of NAD metabolome in aged mice tissue using liquid chromatography tandem‐mass spectrometry

Nicotinamide adenine dinucleotide (NAD) is a major co‐factor that mediates multiple biological processes including redox reaction and gene expression. Recently, NAD metabolism has received considerable attention because administration of NAD precursors exhibited beneficial effects against aging‐related metabolic disorders in animals. Although numerous studies have reported that NAD levels decline with aging in multiple animal tissues, the pathway and kinetics of NAD metabolism in aged organs are not completely understood. To determine the NAD metabolism upon aging, we developed targeted metabolomics based on an LC/MS/MS system. Our method is simple and applicable to crude biological samples, including culture cells and animal tissues. Unlike a conventional enzymatic cycling assay, our approach can determine NAD and NADH (reduced form of NAD) by performing a single sample preparation. Further, we validated our method using biological samples and investigated the alteration of the NAD metabolome during aging. Consistent with previous reports, the NAD levels in the liver and skeletal muscle decreased with aging. Further, we detected a significant increase in nicotinamide mononucleotide and nicotinamide riboside in the kidney upon aging. The LC/MS/MS‐based NAD metabolomics that we have developed is extensively applicable to biomedical studies, and the results will present innovative ideas for the aging studies, especially for that of NAD metabolism.     

Spectroscopic investigation of the composition of electrospun titania nanofibers

We investigate the structure and chemical nature of titania nanofibers synthesized by electrospinning techniques. Fourier transform infrared (FTIR) spectroscopy is used to identify CO₂ clathrates trapped within the nanofiber structures. These molecular species are formed during pyrolysis of the guide polymer. In addition, X‐ray photoelectron spectroscopy (XPS) identifies silicon within the nonwoven sheets. This led us to discover that impurities can be inadvertently incorporated during the electrospinning process from something as simple as a short piece of silicone tubing on a syringe pump. These findings should help advance the field of electrospinning by demonstrating the importance of spectroscopic characterization of materials synthesized by this technique. Copyright © 2006 John Wiley & Sons, Ltd.     

Effects of vitamin d treatment on skeletal muscle histology and ultrastructural changes in a rodent model

Vitamin D is well known for its role in maintaining calcium and phosphorus homeostasis and in promoting bone mineralization; however, more of its pleiotropic effects have been described recently. The aim of the present investigation was to study the effect of vitamin D treatment on skeletal muscles changes under different dietary conditions using an animal model. Four groups of C57BL/6J mice (n = 11 each) were maintained on either low fat diet (LFD) or high fat diet ??(HFD) with and without 1α,25-dihydroxyvitamin D3 (calcitriol) for 16 weeks. Animal weigh was recorded at baseline and then regular intervals, and at the end of the study, skeletal muscle tissues were harvested for the evaluation of the histopathological and ultrastructural changes. When control C57BL/6J mice were fed high-fat diet for 12 weeks, body weight gain was significantly increased compared with mice fed a LFD. (30.2% vs. 8.4%, p < 0.01). There was a significant gradual decrease in the weight of HFD fed mice that were treated with vitamin D as compared with a steady increase in the weights of controls (6.8% vs. 28.7%, p < 0.01). While the LFD group showed some ultrastructural changes, HDF fed on mice showed great muscle structural abnormalities. The whole sarcosome along with its membrane and cristae were severely damaged with scattered myocytes in HFD group. Furthermore, the mitochondria appeared weak and were on the verge of degenerations. The bands were diminished with loss of connections among myofibrils. These changes were attenuated in the HFD group treated with vitamin D with tissues have regained their normal structural appearance. The current findings indicate an important effect of vitamin D on skeletal muscle histology under HFD conditions.     

Effect of low‐temperature physical aging on the dynamic transitions of atactic polystyrene in the glassy state

The local and cooperative dynamics of atactic PS (a‐PS) were studied by broadband dielectric relaxation spectroscopy (BDRS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR). The a‐PS has been subjected to thermal rejuvenation and subsequent quenching, short‐term aging (6 weeks), and long‐term aging (1 year) at ambient conditions. Where for the rejuvenated sample only an α‐ and a γ‐relaxation is observed, short‐term aging results in an additional β*‐relaxation that merges with the α‐relaxation at longer aging times. The γ‐relaxation is increasing in intensity and activation energy during aging. The α‐process shows no spectral changes and shift in the relaxation time upon aging. This may be attributed to a possible erasure of history of the material during the temperature‐sweep mode measurement. Fourier transform infrared spectroscopy (FTIR) results suggest that the energetically favorable trans‐trans (tt) conformers are increased in population with aging. © 2019 The Authors. Journal of Polymer Science Part B: Polymer Physics published by Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1394–1401     

Thermal and vibrational characterization of human skin

For a better understanding of the molecular and organizational changes in human dermis, biophysical methods were tested. The aim of this study was to find suitable and reproducible biomarkers for further clinical studies on intrinsic and extrinsic aging of dermis. Thermoporometry, hydric organization and thermal transitions of fresh and frozen skins were determined by differential scanning calorimetry (DSC). Fourier transform infrared spectroscopy (FTIR) was used to identify the absorption bands of the dermis especially in the 1800–1000 cm^?1 zone and to discriminate between the different secondary structures of proteins. A widening of the pore size distribution is evidenced with freezing, but there is no significant difference between the hydric organization and the endothermic collagen denaturation of fresh and frozen skins. The global FTIR spectra and the second derivative spectra in the scanned zone are also identical in fresh and frozen dermis, validating the storage protocol. DSC and FTIR are well-suited techniques to characterize human skin, giving accurate results with high reproducibility. The acquisition of thermal and vibrational biomarkers of the skin at the mesoscale and nanoscale contributes to its better knowledge and is promising for further studies on skin aging.     

Aging of Polyimides in High Temperature Environments

Summary: Membranes made of high permeable fluorinated aromatic polyimide synthesized from 6FDA (4,4'-hexafluoroisopropylidene diphthalic anhydride) and 4MPD (2,3,5,6-tetramethyl-1,4-phenylene diamine) have been thermally treated to examine their aging behaviour at high temperature. The aging process was investigated by means of gas permeation tests, IR spectroscopy and thermogravimetric analysis combined with mass spectral analysis of the gaseous decomposition products. Up to around 400 °C thin films of the material show no major degradation but changes in color, flexibility and separation characteristics for O₂/N₂ were observed.     

Aging of ethylene-propylene-diene monomer (EPDM) in artificial weathering environment

Ethylene-propylene-diene monomer (EPDM) containing ENB as diene was exposed to artificial weathering environment for different periods of time. The changes of appearance, morphology, mechanical properties and chemical structures were monitored by spectrophotometer, glossmeter, microscope, computer-controlled tensile testing, hardness measurements and Fourier Transform Infrared (FTIR) spectroscopy. Crosslink density of EPDM specimens was measured by the solvent swell method. The results showed that the surface of EPDM became redder, yellower and lighter in the first stage of aging and then remained almost unchanged. The specular gloss reached a maximum when the sample was exposed for 18 days and then decreased. The aging process proceeded predominantly via crosslinking. The tensile strength increased with increase in crosslink density up to an optimum value and thereafter decreased with further increase in crosslink density. FTIR spectra confirmed the formation of carbonyl groups in an artificial weathering environment.     

DISTRIBUTION OF TEMOPORFIN, A NEW PHOTOSENSITIZER FOR THE PHOTODYNAMIC THERAPY OF CANCER, IN A MURINE TUMOR MODEL

Abstract— The biodistribution of temoporfin (tetra[ m -hydroxyphenyl]chlorin, m -THPC), a recently developed photosensitizer, was investigated in BALB/c mice. The drug was administered intravenously (0.35-0.75 μmol/kg) to tumor-free mice or to mice implanted with the Colo 26 colorectal carcinoma. Blood and tissue samples were collected for up to 96 h post-dose. Drug concentrations were determined by HPLC coupled to photometric detection at 423 nm. Concentrations in blood and liver fell relatively rapidly such that blood concentrations at later time points were below the limit of detection. Tumor concentrations rose at first and then remained constant from 24 h. Temoporfin concentrations in some tissues, notably heart and skeletal muscle, declined only slowly when compared to blood. The tumor: tissue ratios for those organs that showed a more rapid decline in temoporfin concentrations were higher at later times, whereas in tissues such as muscle the ratio remained relatively constant. The organs with the highest tumor: tissue ratios were small intestine (8.6), liver (6.9) and skeletal muscle (5.0).     

Oxo‐Functionalized Graphene as a Cell Membrane Carrier of Nucleic Acid Probes Controlled by Aging

We applied a fluorescein‐containing oligonucleotide (ON) to probe surface properties of oxidized graphene (oxo‐G) and observed that graphene‐like patches are formed upon aging of oxo‐G, indicated by enhanced probe binding and by FTIR spectroscopic analysis. By using a recently developed fluorogenic endoperoxide (EP) probe, we confirmed that during the aging process the amount of EPs on the oxo‐G surface is reduced. Furthermore, aging was found to strongly affect cell membrane carrier properties of this material. In particular, freshly prepared oxo‐G does not act as a carrier, whereas oxo‐G aged for 28 days at 4 °C is an excellent carrier. Based on these data we prepared an optimized oxo‐G, which has a low‐defect density, binds ONs, is not toxic, and acts as cell membrane carrier. We successfully applied this material to design fluorogenic probes of representative intracellular nucleic acids 28S rRNA and β‐actin‐mRNA. The results will help to standardize oxidized graphene derivatives for biomedical and bioanalytical applications.     

A Collagen Hydrolysate Containing Tripeptides Ameliorates Sarcopenia in Middle-Aged Mice

Collagen peptide (CP) and collagen tripeptide (CTP) are supplementary health foods that exhibit several biological effects. However, the effects of collagen on age-associated sarcopenia and its underlying mechanisms are unclear. C57BL/6J mice (n = 24, 12 months old) were divided into three dietary groups and administered AIN93G (aging control, AC; JA BIO, Suwon, Korea), AIN93G plus 0.2% CP, and AING93G plus 0.2% CTP supplement for 12 weeks. The results indicated that the CP and CTP supplements significantly increased the weight of the quadriceps tibialis anterior and gastrocnemius muscles and reduced body fat. A morphological analysis revealed that the spaces within the muscle cells were tight with attenuated fibrosis following CP and CTP supplementation. Immunohistochemistry was applied and a Western blot analysis was performed to determine the underlying mechanisms. The CTP supplement increased the expression of IGF-1, PI3K/AKT, and mTOR, whereas the CP supplement increased the expression of IGF-1 and AMPK in the gastrocnemius of aging mice. CP and CTP ameliorate age-associated sarcopenia through different mechanisms.     

Involvement of Neuropeptide Galanin Receptors 2 and 3 in Learning,Memory and Anxiety in Aging Mice

The neuropeptide galanin (GAL), which is expressed in limbic brain structures, has a strong impact on the regulation of mood and behavior. GAL exerts its effects via three G protein-coupled receptors (GAL_1–3-R). Little is known about the effects of aging and loss of GAL-Rs on hippocampal-mediated processes connected to neurogenesis, such as learning, memory recall and anxiety, and cell proliferation and survival in the dorsal dentate gyrus (dDG) in mice. Our results demonstrate that loss of GAL₃-R, but not GAL₂-R, slowed learning and induced anxiety in older (12–14-month-old) mice. Lack of GAL₂-R increased cell survival (BrdU incorporation) in the dDG of young mice. However, normal neurogenesis was observed in vitro using neural stem and precursor cells obtained from GAL₂-R and GAL₃-R knockouts upon GAL treatment. Interestingly, we found sub-strain differences between C57BL/6J and C57BL/6N mice, the latter showing faster learning, less anxiety and lower cell survival in the dDG. We conclude that GAL-R signaling is involved in cognitive functions and can modulate the survival of cells in the neurogenic niche, which might lead to new therapeutic applications. Furthermore, we observed that the mouse sub-strain had a profound impact on the behavioral parameters analyzed and should therefore be carefully considered in future studies.     

Biodistribution assessment of a lutetium(III) texaphyrin analogue in tumor-bearing mice using NIR Fourier-transform Raman spectroscopy

The use of near-infrared (NIR)-excited Fourier-transform (FT) Raman spectroscopy as a technique for evaluating the extent of photosensitizer localization in tumor (human pancreatic adenocarcinomas)-bearing mice has been tested using lutetium(III) texaphyrin analogue Lu-T2B2Tex. The complex was injected subcutaneously in the form of three injections given during the course of 3 days. The kinetics of biodistribution were then followed over a time scale of 1-6 days. The NIR-FT-Raman spectra of tissue samples obtained from the xenographic tumor, muscle, heart, brain, liver, spleen, kidney and blood were recorded and used to identify the presence of Lu-T2B2Tex in these tissues. Five Raman sensitizer markers were used to estimate the relative content of Lu-T2B2Tex in tumor at various postinjection times. UV-Visible (Vis) absorption spectroscopic detection of this sensitizer in tissue extracts was applied as a conventional method. Both spectroscopic methods were in good agreement with each other and confirm that Lu-T2B2Tex localizes well in tumor tissue. Maximal drug content was observed 3 days after the final injection. This time delay seems to be optimal for tumor irradiation in photodynamic therapy.     

有机涂层环境适应性研究进展

综述了有机涂层自然环境试验方法和实验室加速试验方法。自然环境试验方法主要有大气环境试验和海水环境试验;实验室加速试验方法不但包括模拟太阳光、热、湿热、盐雾等环境的实验室试验,还有综合模拟试验。还介绍了检测有机涂层老化的宏观分析方法、微观分析方法和电化学分析方法。其中宏观分析方法主要介绍了涂层附着力试验方法,微观分析方法则主要介绍了扫描电镜(SEM)、X射线光电子能谱仪(XPS)、傅里叶红外光谱(FTIR)及电化学交流阻抗谱法(EIS)。讨论了近年发展起来的有机涂层老化的各种机理,例如自由基降解的光老化降解机理,亲水性基团的水降解机理,热氧机理,臭氧及污染物影响的老化机理等。     

生物多聚糖诱导的金纳米粒子的合成与表征

在不引入其它还原剂和稳定剂的情况下, 加热天然生物多聚糖——壳聚糖(CHIT)和氯金酸的混合溶液, 一步反应制备高稳定性的金纳米粒子(GNPs). 采用紫外光谱、红外光谱、热重分析和透射电镜对产品进行了表征. 结果表明: 改变CHIT的浓度能够调控GNPs的光学和结构性质; 老化-时效处理可以作为粒子增长过程中的一个调控手段. 动力学数据证明GNPs的时效处理过程是一个CHIT诱导的自催化生长过程; 红外谱中1713.3 cm^－1左右出现的新的吸收带, 可能是作为还原剂参加反应的壳聚糖或者它的水解产物分子中的部分羟基被氧化为羰基引起的. 本文工作也为进一步阐明目前还处于探索阶段的纳米粒子的形成机制以及实现其工业化绿色生产提供了可能性.     

Fluorescence and Fourier-transform infrared spectroscopy for the analysis of iconic Italian design lamps made of polymeric materials

The preservation of design object collections requires an understanding of their constituent materials which are often polymeric blends. Challenges associated with aging of complex polymers from objects with an unknown physical history may compromise the interpretation of data from analytical techniques, and therefore complicate the assessment of the condition of polymers in indoor museum environments. This study focuses on the analysis of polymeric materials from three well-known Italian design lamps from the 1960s. To assess the degree of chemical modifications in the polymers, non-destructive molecular spectroscopic techniques, Fourier-transform infrared (FTIR) and fluorescence spectroscopy, have been applied directly on the object surfaces using an optical fiber probe and through examination of micro samples. FTIR spectra of the different polymers, polyvinylacetate (PVAc) for the lamps Taraxacum and Fantasma, and both acrylonitrile–butadiene–styrene polymer (ABS) and cellulose acetate (CA) for the lamp Nesso, allowed the detection of ongoing deterioration processes. Fluorescence spectroscopy proved particularly sensitive for the detection of molecular changes in the polymeric objects, as the spectra obtained from the examined lamps differ significantly from those of the unaged reference materials. Differences in fluorescence spectra are also detected between different points on the same object further indicating the presence of different chemical species on the surfaces. With the aid of complementary data from FTIR spectroscopy, an interpretation of the emission spectra of the studied polymeric objects is here proposed, further suggesting that fluorescence spectroscopy may be useful for following the degradation of historical polymeric objects.