Diffusion-tensor magnetic resonance imaging as a non-invasive assessment of extracellular matrix remodeling in lumbar paravertebral muscles of rats with sarcopenia.

BACKGROUND: Extracellular matrix (ECM) remodeling in skeletal muscle is a significant factor in the development of sarcopenia. This study aims to evaluate changes in ECM remodeling in the lumbar paravertebral muscles of sarcopenic rats using diffusion-tensor magnetic resonance imaging (DT-MRI) and compare them with histology. METHODS: Twenty 6-month-old female Sprague Dawley rats were randomly divided into the dexamethasone (DEX) group and the control (CON) group. Both groups underwent 3.0T MRI scanning, including Mensa, T2WI, and DT-MRI sequences. The changes in muscle fibers and extracellular matrix (ECM) of the erector spinal muscle were observed using hematoxylineosin and sirius red staining. The expressions of collagen I, III, and fibronectin in the erector spinae were detected by western blot. Pearson correlation analysis was employed to assess the correlation between MRI quantitative parameters and corresponding histopathology markers. RESULTS: The cross-sectional area and fractional anisotropy values of the erector spinae in the DEX group rats were significantly lower than those in the CON group (p < 0.05). Hematoxylin eosin staining revealed muscle fiber atrophy and disordered arrangement in the DEX group, while sirius red staining showed a significant increase in collagen volume fraction in the DEX group. The western blot results indicate a significant increase in the expression of collagen I, collagen III, and fibronectin in the DEX group (p < 0.001 for all). Correlation coefficients between fractional anisotropy values and collagen volume fraction, collagen I, collagen III, and fibronectin were - 0.71, -0.94, -0.85, and - 0.88, respectively (p < 0.05 for all). CONCLUSIONS: The fractional anisotropy value is strongly correlated with the pathological collagen volume fraction, collagen I, collagen III, and fibronectin. This indicates that DT-MRI can non-invasively evaluate the changes in extracellular matrix remodeling in the erector spinal muscle of sarcopenia. It provides a potential imaging biomarker for the diagnosis of sarcopenia.

An experimental study for quantitative assessment of fatty infiltration and blood flow perfusion in quadriceps muscle of rats using IDEAL-IQ and BOLD-MRI for early diagnosis of sarcopenia.

BACKGROUND: Severe sarcopenia may result in severe disability. Early diagnosis is currently the key to enhancing the treatment of sarcopenia, and there is an urgent need for a highly sensitive and dependable tool to evaluate the course of early sarcopenia in clinical practice. This study aims to investigate longitudinally the early diagnosability of magnetic resonance imaging (MRI)-based fat infiltration and blood flow perfusion technology in sarcopenia progression. METHODS: 48 Sprague-Dawley rats were randomly assigned into six groups that were based on different periods of dexamethasone (DEX) injection (0, 2, 4, 6, 8, 10 days). Multimodal MRI was scanned to assess muscle mass. Grip strength and swimming exhaustion time of rats were measured to assess muscle strength and function. Immunofluorescence staining for CD31 was employed to assess skeletal muscle capillary formation, and western blot was used to detect vascular endothelial growth factor-A (VEGF-A) and muscle ring finger-1 (MuRF-1) protein expression. Subsequently, we analyzed the correlation between imaging and histopathologic parameters. A receiver operating characteristic (ROC) analysis was conducted to assess the effectiveness of quantitative MRI parameters for discriminating diagnosis in both pre- and post-modeling of DEX-induced sarcopenic rats. RESULTS: Significant differences were found in PDFF, R2* and T2 values on day 2 of DEX-induction compared to the control group, occurring prior to the MRI-CSA values and limb grip strength on day 6 of induction and swimming exhaustion time on day 8 of induction. There is a strong correlation between MRI-CSA with HE-CSA values (r = 0.67; p < 0.001), oil red O (ORO) area with PDFF (r = 0.67; p < 0.001), microvascular density (MVD) (r = -0.79; p < 0.001) and VEGF-A (r = -0.73; p < 0.001) with R2*, MuRF-1 with MRI-CSA (r = -0.82; p < 0.001). The AUC of PDFF, R2*, and T2 values used for modeling evaluation are 0.81, 0.93, and 0.98, respectively. CONCLUSION: Imaging parameters PDFF, R2*, and T2 can be used to sensitively evaluate early pathological changes in sarcopenia. The successful construction of a sarcopenia rat model can be assessed when PDFF exceeds 1.25, R2* exceeds 53.85, and T2 exceeds 33.88.

Functional magnetic resonance imaging reveals dysfunction of the paraspinal muscles in patients with chronic low back pain: a cross-sectional study.

Background: Patients with chronic low back pain (CLBP) undergo structural changes of the paraspinal muscles; however, it is unclear if functional changes also occur. This study aimed to examine the metabolic and perfusion function changes in the paraspinal muscles of patients with CLBP as indirectly reflected by blood oxygen level-dependent (BOLD) imaging and T2 mapping. Methods: All participants were consecutively enrolled at our local hospital from December 2019 to November 2020. Patients were diagnosed with CLBP in the outpatient clinic, and asymptomatic participants were considered to be those with no CLBP or other diseases. This study was not registered on a clinical trial platform. Participants underwent BOLD imaging and T2 mapping scans at the L4-S1 disc level. The effective transverse relaxation rate (R2* values) and transverse relaxation time (T2 values) of the paraspinal muscles were measured on the central plane of the L4/5 and L5/S1 intervertebral discs. Finally, the independent samples t-test was used to assess the differences in R2* and T2 values between the 2 groups, while Pearson correlation analysis was used to determine their correlation with age. Results: A total of 60 patients with CLBP and 20 asymptomatic participants were enrolled. The paraspinal muscles of the CLBP group had higher total R2* values [46.7±2.9 vs. 44.0±2.9 s-1; 95% confidence interval (CI): 1.2-4.2; P=0.001] and lower total T2 values (45.4±4.2 vs. 47.1±3.7 ms; 95% CI: -3.8 to 0.4; P=0.109) than did the asymptomatic participants. For the different muscles, R2* values for the erector spinae (ES) (L4/5: 45.5±2.6 vs. 43.0±3.0 s-1, 95% CI: 1.1-4.0, P=0.001; L5/S1: 48.5±4.9 vs. 45.9±4.2 s-1; 95% CI: 0.2-5.1; P=0.035) and the R2* values of the multifidus (MF) muscles (L4/5: 46.4±2.9 vs. 43.7±3.5 s-1, 95% CI: 1.1-4.3, P=0.001; L5/S1: 46.3±3.5 vs. 42.5±2.8 s-1, 95% CI: 2.1-5.5, P<0.001) of the CLBP group at both spinal levels were higher than those of the asymptomatic participants. In the patients with CLBP, the R2* values at the L4/5 (45.9±2.1 s-1) were lower than those at the L5/S1 (47.4±3.6 s-1; 95% CI: -2.6 to -0.4; P=0.007). The R2* values were positively correlated with age in both groups (CLBP group: r=0.501, 95% CI: 0.271-0.694, P<0.001; asymptomatic group: r=0.499, 95% CI: -0.047 to 0.771; P=0.025). Conclusions: The R2* values were higher in the paraspinal muscles of patients with CLPB and may suggest metabolic and perfusion dysfunction of the paraspinal muscles in these patients.

A Combined Quantitative Evaluation Model for the Capability of Hyperspectral Imagery for Mineral Mapping.

To analyze the influence factors of hyperspectral remote sensing data processing, and quantitatively evaluate the application capability of hyperspectral data, a combined evaluation model based on the physical process of imaging and statistical analysis was proposed. The normalized average distance between different classes of ground cover is selected as the evaluation index. The proposed model considers the influence factors of the full radiation transmission process and processing algorithms. First- and second-order statistical characteristics (mean and covariance) were applied to calculate the changes for the imaging process based on the radiation energy transfer. The statistical analysis was combined with the remote sensing process and the application performance, which consists of the imaging system parameters and imaging conditions, by building the imaging system and processing models. The season (solar zenith angle), sensor parameters (ground sampling distance, modulation transfer function, spectral resolution, spectral response function, and signal to noise ratio), and number of features were considered in order to analyze the influence factors of the application capability level. Simulated and real data collected by Hymap in the Dongtianshan area (Xinjiang Province, China), were used to estimate the proposed model's performance in the application of mineral mapping. The predicted application capability of the proposed model is consistent with the theoretical analysis.

The Regular/Persistent Free Radicals and Associated Reaction Mechanism for the Degradation of 1,2,4-Trichlorobenzene over Different MnO2 Polymorphs.

The role of regular/persistent free radicals on the catalytic activity of K+-tuned MnO2 tunnel structures is poorly understood to date. Herein, three MnO2 polymorphs (α-, ß-, and δ-MnO2) were synthesized and examined toward the degradation of 1,2,4-trichlorobenzene (1,2,4-TrCBz) at 300 °C. δ-MnO2, with a two-dimensional-layered tunnel structure tuned by K+, exhibited the highest activity among the three MnO2 polymorphs. The electron spin resonance spectroscopy results confirmed that δ-MnO2 featured the most abundant reactive oxygen species (ROS: O2-•, •OH, and 1O2), followed by α-MnO2 (O2-• and 1O2), and ß-MnO2 (O2-•), being supported by the calculated energy barrier. It was, intriguingly, noted that persistent organic free radicals, newly recognized as emerging surface-stabilized compound, were remarkably detected in α- and ß-MnO2/1,2,4-TrCBz systems but not in more reactive δ-MnO2/1,2,4-TrCBz system. These might contribute to discrepant oxidative degradation process. During the oxidative process, intermediates, including benzoic acid and glycerol, formed via attack by ROS. Upon further attack, these intermediates fragmented into smaller molecules such as formic, acetic, propionic, and butyric acids. The present findings give deeper insights into the role of free radicals on the catalytic degradation of chlorinated aromatics.

ISBDD Model for Classification of Hyperspectral Remote Sensing Imagery.

The diverse density (DD) algorithm was proposed to handle the problem of low classification accuracy when training samples contain interference such as mixed pixels. The DD algorithm can learn a feature vector from training bags, which comprise instances (pixels). However, the feature vector learned by the DD algorithm cannot always effectively represent one type of ground cover. To handle this problem, an instance space-based diverse density (ISBDD) model that employs a novel training strategy is proposed in this paper. In the ISBDD model, DD values of each pixel are computed instead of learning a feature vector, and as a result, the pixel can be classified according to its DD values. Airborne hyperspectral data collected by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) sensor and the Push-broom Hyperspectral Imager (PHI) are applied to evaluate the performance of the proposed model. Results show that the overall classification accuracy of ISBDD model on the AVIRIS and PHI images is up to 97.65% and 89.02%, respectively, while the kappa coefficient is up to 0.97 and 0.88, respectively.

Effects of atmospheric ageing under different temperatures on surface properties of sludge-derived biochar and metal/metalloid stabilization.

Ageing is a common phenomenon during biochar storage and its soil application. In this study, we exposed sludge-derived biochar (SDBC) in the air under 4 °C, 22 °C, and 45 °C for 30-120 d to imitate the ageing process after SDBC production. The aged SDBC was characterized and its sorption capacities for Pb(II), Cr(V) and As(III) were compared with the fresh ones in batch sorption experiments. The results showed an increase in acidity, cation exchange capacity, and carboxyl groups of SDBC surface, but a decrease in alkalinity and Fe(III) species during ageing, indicating the oxidation. In addition, ageing for more than 30 d was found to favor the Pb(II) and As(III) sorption, because of higher density of available oxygen-containing groups. The Cr(VI) sorption was found to be compromised by the ageing, because some reducing agents for Cr(VI) reduction was consumed there. Higher temperatures accelerated the above-mentioned ageing effect. Yet, when the SDBC was applied in the heavy-metal contaminated soil, its performance would be affected by both ageing of SDBC itself as well as long-term interactions among soil components, such as colloids and solution, heavy metals, and SDBC, which require further investigation.

Determination of hexabromocyclododecanes in sediments from the Haihe River in China by an optimized HPLC-MS-MS method.

Hexabromocyclododecanes (HBCDs), a new type of persistent organic pollutants widely used as brominated flame retardants, have attracted wide attention due to their increasing level and toxicity. A method based on high-performance liquid chromatography mass spectrometry (HPLC-MS-MS) in electrospray ionization mode has been developed by optimization of various parameters, which effectively improved the separation degree and responsive intensity of α-, ß- and γ-HBCD isomers. The concentrations and distribution profiles of three HBCD isomers were investigated in sediments from the Haihe River in China. It was observed that the concentrations of HBCDs varied in the range of 0.4-58.82ng/g, showing a decreasing trend along the flow direction, possibly due to attenuation and biodegradation along the flow direction of the Haihe River. The distribution profile of α-, ß-, γ-HBCD was 7.91%-88.6%, 0-91.47%, and 0.62%-42.83%, respectively. Interestingly, α-HBCD dominated in most sample sites. This was different from the distribution profile in commercial industrial products, which might be attributed to the inter-transformation and different degradation rates of the three HBCD isomers. The potential ecological risk of HBCDs in sediment was characterized under the two-tiered procedure of the European Medicines Evaluation Agency for environmental risk assessment. Although the HBCDs in the selected section of the Haihe River presented "no risk" in the sediment compartment, its risk in sediment cannot be neglected since sediment is one of the important sinks and reservoirs of pollutants.

Metal immobilization by sludge-derived biochar: roles of mineral oxides and carbonized organic compartment.

Pyrolyzing sludge into biochar is a potentially promising recycling/disposal solution for municipal wastewater sludge, and the sludge-derived biochar (SDBC) presents an excellent sorbent for metal immobilization. As SDBC is composed of both mineral oxides and carbonized organic compartment, this study therefore compared the sorption behaviour of Pb and Zn on SDBC to those of individual and mixture of activated carbon (AC) and amorphous aluminium oxide (Al2O3). Batch experiments were conducted at 25 and 45 °C, and the metal-loaded sorbents were artificially aged in the atmosphere for 1-60 days followed by additional sorption experiments. The Pb sorption was generally higher than Zn sorption, and the co-presence of Pb reduced Zn sorption on each studied sorbent. Higher sorption capacities were observed at 45 °C than 25 °C for SDBC and AC, while the opposite was shown for Al2O3, indicating the significance of temperature-dependent diffusion processes in SDBC and AC. Nevertheless, metal sorption was more selective on Al2O3 that showed a greater affinity towards Pb over Zn under competition, correlating with the reducible fraction of sequential extraction. Furthermore, significant amounts of Pb and Zn were additionally sorbed on SDBC following 30-day ageing. The X-ray diffraction revealed the formation of metal-phosphate precipitates, while the X-ray photoelectron spectroscopy showed a larger quantity of metal-oxygen bonding after 30-day ageing of metal-loaded SDBC. The results may imply favourable long-term transformation and additional sorption capacity of SDBC. In conclusion, SDBC resembles the sorption characteristics of both organic and mineral sorbents in different aspects, presenting an appropriate material for metal immobilization during soil amendment.

[Development of Self-assembled Dumbbell-like Fe3O4 Micro/nanomaterial for Application in Thermocatalytic Degradation of Polybrominated Biphenyls].

Polybrominated biphenyls (PBBs) are a group of new persistent organic pollutants, which have high toxicity and long-term bioaccumulation, and cause potential risks to human beings and aquatic ecosystem. Self-assembled dumbbell-like Fe3O4 was synthesized via ethylene-glycol mediated method to degrade PBBs, using BB209 as a model compound. The results showed that the growth process of dumbbell-like Fe3O4 precursor had two stages involving a fast nucleation of amorphous primary particles followed by a slow aggregation and crystallization of primary particles. Dumbbell-like Fe3O4 showed high activity for degradation of BB209 at the reaction time of 30 min with the degradation efficiency of nearly 100% at 300 degrees C. A whole series of nonabromobiphenyl to monobromobiphenyl and biphenyls were detected as the degradation products of BB209 by dumbbell-like Fe3O4, indicating the occurrence of successive hydrodebromination reaction. Furthermore, the amounts of three NoBB isomers followed the order of BB207 > BB208 > BB206, indicating that the reactivity of C--Br of BB209 was in order of meta- > para- > ortho-positions.

Synergetic inhibition of PCDD/F formation from pentachlorophenol by mixtures of urea and calcium oxide.

Chlorophenols are structurally similar to PCDD/Fs and have been considered as highly potential precursors for PCDD/Fs formation. The suppressing effects of PCDD/F formation from pentachlorophenol (PCP) were investigated on various mass ratios of CaO and urea. The total concentration of 2,3,7,8-PCDD/Fs, mostly dominated by OCDD, was determined to be 48.58-10186ng/mg in inhibitor-reaction systems, being much lower than that in blank reaction system (75654ng/mg). Interestingly, compared with pure CaO and urea reaction system, the concentration and TEQ of formed 2,3,7,8-PCDD/Fs in mixed urea/CaO reaction system were lower, especially with 5-20% urea reaction systems being respectively at decrease by 96.5-99.4% and 99.2-99.7%. The suppression efficiency of TEQ in 5-20% urea reaction systems could be always approximately 100% under 250-350°C. These results suggested that mixed inhibitors, especially 5-20% urea inhibitors, have a synergetic inhibition effect for PCDD/Fs formation from PCP. Mixed inhibitor generated several intermediates, involving CO2, H2O, NH3, Ca(OH)2, CaCO3, HNCO, biuret and ammelide. The complex between PCP and Ca, N-doped species, lower chlorinated phenols and benzenediol, and organic acids were also determined. Synergetic inhibition mechanism may be attributed to accelerated facilitation of acid-base reaction and N doping. The decomposition of PCP itself also contributes to prevent PCDD/Fs formation.

Thermal degradation of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) over synthesized Fe-Al composite oxide.

A series of Fe-Al composite oxides were synthesized by the hydrothermal method using different urea dosages and examined towards the degradation of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) at 300 °C. The as-prepared oxides were characterized by field-emission scanning electron microscopy, X-ray diffraction and energy-dispersive X-ray spectroscopy. The morphology and composition of the prepared materials could be regulated by controlling the urea concentration. Interestingly, these properties influenced the nature and amount of the hydrodebromination products generated during the degradation of BDE-47. The degradation of BDE-47 over the composite oxide prepared at a urea dosage of 3 mmol generated BDE-17 as the major isomer product, followed by BDE-28/33, -30, and -32, among the tribromodiphenyl ethers (tri-BDEs). Regarding the dibromodiphenyl ethers (di-BDEs) produced, the amount of the isomers decreased in the order of BDE-8/11 > BDE-7 > BDE-15 > BDE-10. And the BDE-1 among monobromodiphenyl was determined. In contrast, over the composite oxides prepared at urea dosages greater than 3 mmol, BDE-28/33 gradually become the major isomer product instead of BDE-17 among tri-BDEs. The amount of the other di-BDEs isomer such as BDE-15 and -10 approach to be comparable to that BDE-8/11. However, regardless of the urea dosage, BDE-47 converted into BDE-75 via an isomerization reaction. Based on these intermediate products identification, a possible hydrodebromination mechanism of BDE-47 over Fe-Al composite oxide was comprehensively traced.