The worldwide incidence of differentiated thyroid cancer (DTC) has increased in recent decades, likely due to frequent use of cervical ultrasonography (US) and US-guided fine needle aspiration biopsy ...(FNA)., US is performed during follow-up after thyroidectomy, and US-guided FNA with cytology is used if suspicious cervical lymph nodes (LN) or thyroid bed masses are detected. Knowing that serum anti-Tg antibodies (sTgAb) affect the use of serum Tg (sTg) as a tumor marker, the aim of our study was to assess the usefulness of Tg determination in needle aspirates (FNA-Tg) in presence of sTgAb. This retrospective study included 149 patients with DTC and 159 aspirations of suspicious LN and thyroid bed masses. As expected, there was a negative correlation between sTg and sTgAb levels (p<0.05), while FNA-Tg levels had a positive correlation with FNA-TgAb levels (p<0.05). Furthermore, we found a positive correlation between sTg and FNA-Tg levels (p<0.05), but not between sTgAb and FNA-TgAb or sTgAb and FNA-Tg. In conclusion, these results show that FNA-Tg values were not affected by sTgAb and that FNA-Tg measurement were highly effective in detecting cervical DTC metastases. However, combined use with cytology is suggested for neck evaluation because cytology could reveal metastases from other tumor sites.
In this study, we focus on the molecular mechanisms associated with the A57G (Ala57‐to‐Gly57) mutation in myosin essential light chains (ELCs), found to cause hypertrophic cardiomyopathy (HCM) in ...humans and in mice. Specifically, we studied the effects of A57G on the super‐relaxed (SRX) state of myosin that may contribute to the hypercontractile cross‐bridge behavior and ultimately lead to pathological cardiac remodeling in transgenic Tg‐A57G mice. The disease model was compared to Tg‐WT mice, expressing the wild‐type human ventricular ELC, and analyzed against Tg‐Δ43 mice, expressing the N‐terminally truncated ELC, whose hearts hypertrophy with time but do not show any abnormalities in cardiac morphology or function. Our data suggest a new role for the N terminus of cardiac ELC (N‐ELC) in modulation of myosin cross‐bridge function in the healthy as well as in HCM myocardium. The lack of N‐ELC in Tg‐Δ43 mice was found to significantly stabilize the SRX state of myosin and increase the number of myosin heads occupying a low‐energy state. In agreement, Δ43 hearts showed significantly decreased ATP utilization and low actin‐activated myosin ATPase compared with A57G and WT hearts. The hypercontractile activity of A57G‐ELC cross‐bridges was manifested by the inhibition of the SRX state, increased number of myosin heads available for interaction with actin, and higher ATPase activity. Fiber mechanics studies, echocardiography examination, and assessment of fibrosis confirmed the development of two distinct forms of cardiac remodeling in these two ELC mouse models, with pathological cardiac hypertrophy in Tg‐A57G, and near physiologic cardiac growth in Tg‐Δ43 animals.
Antagonistic mechanism by which ELC mutations regulate the super‐relaxed state of myosin and the development of pathological‐ (A57G) versus physiologic‐like (Δ43) phenotypes in ELC models of cardiac hypertrophy. The A57G mutation promotes the SRX‐to‐DRX transition that mechanistically underlies the HCM clinical phenotype of hypercontractility. The lack of N‐ELC promotes the SRX‐sequestered state of cardiac myosin, highlighting the importance of the N terminus ELC in maintaining optimal myosin function and heart performance.
•First study on kinetic behaviors and evolved gaseous products for SMS combustion.•Four iso-conversional models were adopted to calculate thermodynamic parameters.•Peak of CO2 and NO2 emissions ...occurred at the stage of fixed carbon combustion.•SO2 was released at devolatilization stage with a peak value of 334.21 °C.
The present study systematically investigated the combustion characteristics of spent mushroom substrate (SMS) using TG-MS (thermogravimetric/mass spectrometry) and TG-FTIR (thermogravimetric/Fourier transform infrared spectrometry) under five heating rates. The physicochemical characteristics and combustion index pointed to SMS as a promising biofuel for power generation. The high correlation coefficient of the fitting plots and similar activation energy calculated by various methods indicated that four suitable iso-conversional methods were used. The activation energy varied from 130.06 to 192.95 kJ/mol with a mean value of 171.49 kJ/mol using Flynn–Wall–Ozawa and decreased with the increased conversion degree. The most common emissions peaked at the range of 200–400 °C corresponding to volatile combustion stage, except for CO2, NO2 and NO. The peak CO2 emission occurred at 439.11 °C mainly due to the combustion of fixed carbon.
Energetic materials have been widely investigated experimentally and theoretically for decades, but there are still many unanswered questions concerning their thermal decomposition mechanisms that ...play a key role in the overall reaction processes. Hyphenated analytical techniques of thermal analysis, such as thermogravimetry coupled either with infrared (TG-FTIR) or mass spectroscopies (TG-MS) have been revealed to be efficient methods for studying such mechanisms. These methods allow the exploration of the evolved gases during the thermal decomposition, which let to trace back the chemical decomposition mechanisms and allows better control of the thermal behavior of various energetic formulations. In this overview, a classification, characterization and properties of energetic material are introduced. Next, advances in the application of two hyphenated techniques (TG-FTIR and TG-MS) along with appropriate examples are discussed. These techniques offer remarkable improvements by enhancing the amount of authentic information obtained with better reproducibility compared to conventional techniques. This first review article dedicated solely to the application of TG on-line coupled with an IR or MS spectrometer, by means of a heater transfer line, will certainly help researchers to easily understand the behavior of energetic materials as well as the development of new applications.
•APOE transgenic mouse models of Alzheimer’s disease have evolved overtime to include various methods to knock-down or express apolipoprotein E.•Limitations of current APOE transgenic models include ...comparing FAD/m-APOE with FAD/APOE-/- mice to determine the effect of APOE on AD pathology.•Few recent models are phenotypically characterized by APOE isoform with genetic (sex, age) and modifiable (e.g., inflammation, obesity) Alzheimer’s disease risk factors.•New data presented further characterizes the EFAD mice and supports the interactive effects of APOE genotype with sex on FAD-induced pathology.
Identified in 1993, APOE4 is the greatest genetic risk factor for Alzheimer’s disease (AD), increasing risk up to 15-fold compared to the common variant APOE3. Since the mid 1990’s, transgenic (Tg) mice have been developed to model AD pathology and progression, primarily via expression of the familial AD (FAD) mutations in the presence of mouse-APOE (m-APOE). APOE4, associated with enhanced amyloid-β (Aβ) accumulation, has rarely been the focus in designing FAD-Tg mouse models. Initially, FAD-Tg mice were crossed with human (h)-APOE driven by heterologous promoters to identify an APOE genotype-specific AD phenotype. These models were later supplemented with FAD-Tg mice crossed with APOE-knockouts (APOE-/- or APOE-KO) and h-APOE-targeted replacement (h-APOE-TR) mice, originally generated to study the role of APOE genotype in peripheral lipid metabolism and atherosclerotic lesion development. Herein, we compare the m- and h-APOE multi-gene clusters, and then critically review the relevant history and approaches to developing a Tg mouse model to characterize APOE-dependent AD pathology, in combination with genetic (sex, age) and modifiable (e.g., inflammation, obesity) risk factors. Finally, we present recent data from the EFAD mice, which express 5xFAD mutations with the expression of the human apoE isoforms (E2FAD, E3FAD and E4FAD). This includes a study of 6- and 18-month-old male and female E3FAD and E4FAD, a comparison that enables examination of the interaction among the main AD risk factors: age, APOE genotype and sex. While no single transgenic mouse can capture the effects of all modifiable and genetic risk factors, going forward, a conscious effort needs to be made to include the factors that most significantly modulate AD pathology.
•The structures of PL and MWL from the same biomass were characterized.•Pyrolysis behaviors of PL and MWL were compared using TG–FTIR.•Double-Gaussian DAEM was introduced to analyze the thermal ...reaction kinetics.•The relationship between chemical structure and pyrolysis behavior was discussed.
Pyrolytic lignin (PL), the main water-insoluble fraction in bio-oil, has an obvious negative effect on the application of biomass pyrolysis technology. The structures of PL and milled wood lignin (MWL) have been characterized and compared using FTIR, 1H NMR, 13C NMR and GPC. The PL was extracted from bio-oil produced by pyrolysis of a hardwood, lauan, while the MWL was isolated directly from the same lauan. The results show that PL is composed mainly of trimers and tetramers, and its average molecular weight is about one tenth of that of MWL. The proportion of methoxy groups and ether linkages in PL were lower than that in MWL. However, PL had a larger amount of unconjugated CO functional groups and saturated aliphatic structures than MWL. Furthermore, a thermogravimetric (TG) study reveals that PL has poor thermal stability and decomposes over a lower temperature range. The double-Gaussian distributed activation energy model (DG-DAEM) is introduced to analyze the thermal reaction kinetics of PL and MWL. The apparent activation energies of PL and MWL are distributed mainly in the first Gaussian region. The evolution characteristics of typical products from the pyrolysis of PL and MWL are also discussed and compared in detail.
Two sets of experiments, categorized as TG–FTIR and Py–GC–FTIR, are employed to investigate the mechanism of the hemicellulose pyrolysis and the formation of main gaseous and bio-oil products. The ...“sharp mass loss stage” and the corresponding evolution of the volatile products are examined by the TG–FTIR graphs at the heating rate of 3–80
K/min. A pyrolysis unit, composed of fluidized bed reactor, carbon filter, vapour condensing system and gas storage, is employed to investigate the products of the hemicellulose pyrolysis under different temperatures (400–690
°C) at the feeding flow rate of 600
l/h. The effects of temperature on the condensable products are examined thoroughly. The possible routes for the formation of the products are systematically proposed from the primary decomposition of the three types of unit (xylan, O-acetylxylan and 4-O-methylglucuronic acid) and the secondary reactions of the fragments. It is found that the formation of CO is enhanced with elevated temperature, while slight change is observed for the yield of CO
2 which is the predominant products in the gaseous mixture.
•A kinetic scheme with five parallel reactions was proposed for peat pyrolysis.•The majority of gas products were released during organic matter decomposition.•Light gas species were detected due to ...hemillulose and cellulose pyrolysis.•Some aromatic hydrocarbons were identified due to lignin degradation.
Thermal characteristics and gas compositions during peat pyrolysis under helium atmosphere were investigated using the TG–FTIR-MS coupling technique. The majority of gas products were released during the decomposition temperature of 150–550°C, resulting in about 60% mass loss of peat. The main gas species detected during 150–400°C were CO2, CO, CH4, C2H6, HCOOH, CH3CH2COOH, C4H8 and CH2CHCHO. From 400°C to 550°C, some aromatic hydrocarbons were identified, including benzaldehyde, phenol, benzoic acid and toluene. The release of CO2, CO, CH4 and some aromatic hydrocarbons over 550°C provided the evidence of char pyrolysis. A five-step pyrolysis scheme including water evaporation, hemicellulose, cellulose and lignin degradation, and char pyrolysis was used to simulate peat decomposition process in inert atmosphere. The well agreement between the calculated and experimental curves indicated that major aliphatic gases were derived from hemicellulose and cellulose pyrolysis, while aromatic hydrocarbons were mainly from lignin and char pyrolysis. This work provides a deep insight into the utilization of peat for gaseous biofuels.
► Pyrolysis and combustion of pine sawdust were investigated with TG–FTIR and Py–GC/MS analysis. ► Kinetic parameters for pine sawdust pyrolysis and combustion process were obtained. ► The gaseous ...species were identified by the spectra: H2O, CO2, CO, CH4, phenols, and paraffin gas. ► The main compounds of pine sawdust thermal decomposing were organic acid, aldehyde and acid anhydride group.
Pyrolysis and combustion of pine sawdust have been investigated by using thermogravimetric analyzer coupled with Fourier transform infrared spectrometry (TG–FTIR) analysis in this paper. Pyrolysis–gas chromatography and mass spectrometry (Py–GC/MS) analysis was employed to characterize subsequently the structure and composition of evolving gas in pine sawdust pyrolysis process. TG results showed that both pyrolysis and combustion of pine sawdust presented three weight loss stages, respectively. The apparent activation energy of pyrolysis reaction is 108.18kJmol−1 in temperature of 239–394°C, while under combustion process which is 128.43kJmol−1 and 98.338kJmol−1 in 226–329°C and 349–486°C, respectively. The evolving gaseous products during the pyrolysis and combustion infrared spectrums such as H2O, CH4, CO, CO2, phenol and alkane were found. Py–GC/MS results indicated that the main compounds of pine sawdust thermal decomposition were small molar gases, acetaldehyde, acetic acid, anhydride with formic and acetic anhydride. And possible formation pathways for main pyrolysis products were tentatively presented.
Pyrolysis is the first step of gasification and combustion. The pyrolysis process of biomass is complicated, which is generally considered to consist of the pyrolysis of the three major components ...(i.e., cellulose, hemicellulose, and lignin). Understanding the pyrolysis behavior and product of each component holds a key to understanding the biomass pyrolysis mechanism. In this work, the pyrolysis behavior, pyrolysis kinetics, volatile evolution, and product characterization of the three major components are investigated. Results showed that pyrolysis characteristics and thermal stability of the three components were closely related to their unique chemical structures. During pyrolysis, the main pyrolytic volatiles of hemicellulose appeared first, followed by cellulose and then lignin volatiles in the 3D FTIR spectra. In term of pyrolysis products, gases were generated by the cracking of specific functional groups. Hemicellulose had the highest CO2 yield, whereas lignin had the highest CH4 yield due to the aromatic rings and methoxy groups in lignin structure. Whereas cellulose demonstrated the highest CO yield at high temperatures (above 550 °C). With increasing temperature, the carbon structures of carboxylic-C and O-alkyl-C in biochar decreased, while aryl-C was enhanced. This was due to the deoxygenation reactions such as dehydroxylation, decarboxylation, decarbonylation, and demethoxylation, resulting in a reduction in the number of oxygen-containing functional groups (such as –OH, –C=O, –COOH, and –OCH3), as well as the polycondensation reactions that formed more polycyclic aromatic hydrocarbon units during pyrolysis. The major components of cellulose bio-oil included anhydrosugars and furans. Whereas the bio-oils derived from hemicellulose and lignin showed the highest relative content of acids and phenols, respectively. Based on this analysis, the thermal decomposition pathways of cellulose, hemicellulose, and lignin were proposed.
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