In Situ Thermal Denaturation of Proteins in Dunning AT-1 Prostate Cancer Cells: Implication for Hyperthermic Cell Injury

The in situ thermal protein denaturation and its correlation with direct hyperthermic cell injury in Dunning AT-1 prostate tumor cells were investigated in this study. The in situ thermal protein denaturation was studied using both Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The FTIR spectra at different temperatures show changes in protein secondary structure (from alpha helix to extended beta sheet) during in situ thermal protein denaturation within AT-1 cells. Calorimetric studies using DSC show that endothermic heat release is associated with the in situ thermal protein denaturation. Furthermore, both the secondary structure changes detected by FTIR and the calorimetric changes detected by DSC were quantified and the kinetics of the overall in situ thermal protein denaturation was derived under different heating conditions. The onset temperature where the overall in situ thermal protein denaturation is first detectable was found to be scanning rate dependent (approximately 41 degrees C at 2 degrees C min(-1) and approximately 44 degrees C at 5 degrees C min(-1)). The kinetics of the overall in situ thermal protein denaturation was derived from both DSC and FTIR measurements and was fit using kinetic and statistical models. The kinetic data determined by FTIR and DSC under the same heating conditions match well with each other. The activation energy of the overall in situ thermal protein denaturation is found to be strongly dependent on the temperature range considered (the activation energy ranges from approximately 110 kJ mol(-1) between 44 and 90 degrees C to approximately 750 kJ mol(-1) between 44 and 50 degrees C). However, its dependence on heating rate is negligible. Several denaturation peaks, including a dominant one between approximately 62 and 65 degrees C, are identifiable from both the DSC and the FTIR results. To investigate directly the relationship between thermally induced cell injury and the in situ thermal protein denaturation, both acute (propidium iodide dye exclusion, assessed 3-h postthermal treatment) and chronic (clonogenics, assessed 7-day postthermal treatment) cell injury were quantified using AT-1 cells prepared under the same conditions as for the DSC protein studies. Comparisons of the results from the cell injury studies and the DSC protein denaturation studies show that the overall in situ thermal protein denaturation correlates well with both the acute and the chronic cell injury, which suggests that overall in situ thermal protein denaturation is an important mechanism of direct hyperthermic cell injury in AT-1 cells at the macromolecular level.     

鹿茸的FTIR性质与传统质量等级之关系

研究了鹿茸的傅里叶变换红外光谱(FTIR)特性与传统质量的关系。发现鹿茸质量等级的内在数字化“Z”值规律性。从而为鹿茸片特别是用目前方法难于确定质量等级的鹿茸粉,提供了质量等级的客观指标。     

煤快速加氢热解焦油组成的分析

采用溶剂萃取－化学处理－柱层析相结合的预处理分离程序、色－质联用和色－红联用结合色谱保留值的定性方法,分析研究了内蒙东胜煤快速加氢热解焦油的化学成分和结构,推测鉴定出２００多种化合物,并对具有代表性的１９种多环芳烃进行了定量分析,讨论了快速加氢热解焦油化学成分的结构特征。     

FTIR Characterization of the Secondary Structure of Insulin Encapsulated within Liposome

Aim:To determine the secondary structure of insulin encapsulated within liposome.Methods:The secondary structure of native insulin,mixture of insulin with liposome(sample I) and insulin encapsulated within liposome(sample Ⅱ) were determined by FTIR(Fourier Transform Infrared) spectroscopy.Results:The secondary structure of insulin encspsulated within liposome(Ⅱ） are similar with the secondary structure of native insulin.The difference existed in the amount of α-helices (from 36% of insulin to 31% of sample Ⅱ）and β-sheet(from 48% of insulin to 51% of sample Ⅱ).The content of α-helices and β-sheet of insulin in sample I was found to be very close to that of sample Ⅱ.The results revealed that the insulin encapsulated within liposome possibly spread on the surface of liposome,without inserting into the liposome membrane.Coclusion:The secondary structure of insulin encapsulated within liposome is similar with the native insulin.     

Multiscale Femoral Neck Imaging and Multimodal Trabeculae Quality Characterization in an Osteoporotic Bone Sample

Although multiple structural, mechanical, and molecular factors are definitely involved in osteoporosis, the assessment of subregional bone mineral density remains the most commonly used diagnostic index. In this study, we characterized bone quality in the femoral neck of one osteoporotic patients as compared to an age-matched control subject, and so used a multiscale and multimodal approach including X-ray computed microtomography at different spatial resolutions (pixel size: 51.0, 4.95 and 0.9 µm), microindentation and Fourier transform infrared spectroscopy. Our results showed abnormalities in the osteocytes lacunae volume (358.08 ± 165.00 for the osteoporotic sample vs. 287.10 ± 160.00 for the control), whereas a statistical difference was found neither for shape nor for density. The osteoporotic femoral head and great trochanter reported reduced elastic modulus (Es) and hardness (H) compared to the control reference (−48% (p < 0.0001) and −34% (p < 0.0001), respectively for Es and H in the femoral head and −29% (p < 0.01) and −22% (p < 0.05), respectively for Es and H in the great trochanter), whereas the corresponding values in the femoral neck were in the same range. The spectral analysis could distinguish neither subregional differences in the osteoporotic sample nor between the osteoporotic and healthy samples. Although, infrared spectroscopic measurements were comparable among subregions, and so regardless of the bone osteoporotic status, the trabecular mechanical properties were comparable only in the femoral neck. These results illustrate that bone remodeling in osteoporosis is a non-uniform process with different rates in different bone anatomical regions, hence showing the interest of a clear analysis of the bone microarchitecture in the case of patients’ osteoporotic evaluation.     

Extraction Optimization and Structural Characteristics of Chitosan from Cuttlefish (S. pharaonis sp.) Bone

In fish processing, reducing the waste rate and increasing the economic value of products is an important issue for global environmental protection and resource sustainability. It has been discovered that cuttlefish bones can be an excellent resource for producing attractive amounts of chitin and chitosan. Therefore, this study optimized chitosan extraction conditions using response surface methodology (RSM) to establish application conditions suitable for industrial production and reducing environmental impact. In addition, Fourier-transform infrared spectroscopy (FTIR), ¹H NMR and scanning electron microscope (SEM) characteristics of extracted chitosan were evaluated. The optimum extraction conditions for chitosan from cuttlebone chitin were 12.5M NaOH, 6 h and 80 °C, and the highest average yield was 56.47%. FTIR spectroscopy, ¹H NMR, and SEM identification proved that the chitosan prepared from cuttlefish bone has a unique molecular structure, and the degree of deacetylation of chitosan was about 81.3%. In addition, it was also confirmed that chitosan has significant anti-oxidation and oil-absorbing abilities. This research has successfully transformed the by-products of cuttlefish processing into value-added products. The process not only achieved the recycling and utilization of by-products but also enhanced industrial competitiveness and resource sustainability.     

Liposome System for Encapsulation of Spirulina platensis Protein Hydrolysates: Controlled-Release in Simulated Gastrointestinal Conditions,Structural and Functional Properties

This study aimed to evaluate the physicochemical, structural, antioxidant and antibacterial properties of chitosan-coated (0.5 and 1% CH) nanoliposomes containing hydrolyzed protein of Spirulina platensis and its stability in simulated gastric and intestine fluids. The chitosan coating of nanoliposomes containing Spirulina platensis hydrolyzed proteins increased their size and zeta potential. The fourier transform infrared spectroscopy (FT-IR) test showed an effective interaction between the hydrolyzed protein, the nanoliposome, and the chitosan coating. Increasing the concentration of hydrolyzed protein and the percentage of chitosan coating neutralized the decreasing effect of microencapsulation on the antioxidant activity of peptides. Chitosan coating (1%) resulted in improved stability of size, zeta potential, and poly dispersity index (PDI) of nanoliposomes, and lowered the release of the hydrolyzed Spirulina platensis protein from nanoliposomes. Increasing the percentage of chitosan coating neutralized the decrease in antibacterial properties of nanoliposomes containing hydrolyzed proteins. This study showed that 1% chitosan-coated nanoliposomes can protect Spirulina platensis hydrolyzed proteins and maintain their antioxidant and antibacterial activities.     

A Study on the Photopolymerization Kinetics of Selected Dental Resins Using Fourier Infrared Spectroscopy (FTIR)

The aim of the presented study was a comparative analysis of the polymerization kinetics of dental resin-based composites currently used in dentistry in different environmental conditions (irradiance, activation time, layer thickness). The photopolymerization kinetics of eleven dental resins were investigated using a Woodpecker LED source. The DC was measured by FTIR in transmission mode and attenuated total reflection (ATR) from 5 s to 7 days. In the transmission mode, the spectra from parallel optical layers (about 0.2 mm thick) of samples placed between the KBr crystals were recorded. In the reflection mode, an ATR attachment with a diamond window was used. The DC calculation method was applied based on the application of a monomer absorption band at 1638 cm⁻¹ (stretching vibration double bond C=C of the vinyl group) without using a reference band. The data were analyzed by performing an ANOVA test comparison between sample groups at the significance level α = 0.05. For all tested materials, the polymerization kinetics consist of three stages. The fastest stage occurs during the irradiation, and the achieved DC value is 70–75% of the maximum value 5 s after the irradiation. Another 15–20% DC increase at a moderate speed takes about 15–20 min. There is also a very slow further increase in DC of 5–10% within 5 days after irradiation. For 8 out of the 11 tested fillings, the optimal photopolymerization conditions are as follows: a power density of 400 or 1000 mW/cm²; an exposure time of 10 s; and a thickness of the irradiated resin layer of up to 2 mm. The influence of various conditions and factors on the reaction kinetics is dominant only in the early, rapid phase of the conversion. After longer times, the DC values gradually level out under different light conditions. The DC of the dental resins are dependent on the irradiance, light source, filler type, time after irradiance, and monomer thickness.     

Selected Physical and Spectroscopic Properties of TPS Moldings Enriched with Durum Wheat Bran

The impact of the amount of durum wheat bran additive used on the selected structural, mechanical, and spectroscopic properties of thermoplastic starch moldings was examined in this study. Bran was added to corn starch from 10 to 60% by weight in the blends. Four temperature settings were used for the high-pressure injection: 120, 140, 160, and 180 °C. The highest value of elongation at break (8.53%) was observed for moldings containing 60% bran. Moreover, for these moldings, the tensile strength and flexural strength were lower (appropriately 3.43 MPa and 27.14 MPa). The highest deformation at break (1.56%) were obtained for samples with 60% bran and injection molded at 180 °C. We saw that higher bran content (50 and 60%) and a higher injection molding temperature (160 °C and 180 °C) significantly changed the color of the samples. The most significant changes in the FTIR spectra were observed at 3292 and 1644 cm⁻¹ and in the region of 1460–1240 cm⁻¹. Moreover, notable changes were observed in the intensity ratio of bands at 1015 and 955 cm⁻¹. The changes observed correspond well with the amount of additive used and with the injection temperature applied; thus it may be considered as a marker of interactions affecting plasticization of the material obtained.     

肉豆蔻及其混淆品长形肉豆蔻的FTIR直接鉴别

目的：直接准确地鉴别肉豆蔻及其混淆品长形肉豆蔻。方法：采用傅里叶变换红外光谱法直接鉴别肉豆蔻及其混淆品长形肉豆蔻。结果：肉豆蔻及其混淆品长形肉豆蔻的红外光谱吸收差别较大。结论：可以采用FTIR法直接、快速、准确地鉴别肉豆蔻及其混淆品长形肉豆蔻。