Enhanced chondrogenic differentiation of human mesenchymal stems cells on citric acid-modified chitosan hydrogel for tracheal cartilage regeneration applications

Congenital tracheal stenosis in infants and children is a worldwide clinical problem. Tissue engineering is a promising method for correcting long segmental tracheal defects. Nonetheless, the lack of desirable scaffolds always limits the development and applications of tissue engineering in clinical practice. In this study, a citric-acid-functionalized chitosan (CC) hydrogel was fabricated by a freeze–thaw method. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) confirmed that citric acid was successfully attached to the chitosan hydrogel. Scanning electron microscopy (SEM) images and compression tests showed that the CC hydrogel had an interconnected porous structure and better wet mechanical properties. Using morphological and proliferation analyses, cell biocompatibility of the CC hydrogel was shown by culturing human mesenchymal stem cells (hMSCs) on it. Specific expression of cartilage-related markers was analyzed by real-time polymerase chain reaction and western blotting. The expression of chondrocytic markers was strongly upregulated in the culture on the CC hydrogel. Hematoxylin and eosin staining revealed that the cells had the characteristic shape of chondrocytes and clustered into the CC hydrogel. Both Alcian blue staining and a sulfated glycosaminoglycan (sGAG) assay indicated that the CC hydrogel promoted the expression of glycosaminoglycans (GAGs). In a nutshell, these results suggested that the CC hydrogel enhanced chondrogenic differentiation of hMSCs. Thus, the newly developed CC hydrogel may be a promising tissue-engineered scaffold for tracheal cartilage regeneration.

A novel citric acid functionalized chitosan hydrogel for tracheal cartilage regeneration applications.     

A first-principles study on Si24 as an anode material for rechargeable batteries

Due to its intriguing geometry, possessing an open-channel structure, Si₂₄ demonstrates potential for storing and/or transporting Li/Na ions in rechargeable batteries. In this work, first-principles calculations were employed to investigate the phase stability and Li/Na storage and transport properties of the Si₂₄ anode to evaluate its electrochemical performance for batteries. The intercalation of Li and Na into the Si₂₄ structure could deliver a capacity of 159 mA h g⁻¹ (Li₄Si₂₄ and Na₄Si₂₄), and the average intercalation potentials were 0.17 V (vs. Li) and 0.34 V (vs. Na). Moreover, the volume change of Si₂₄ upon intercalation proved very small (0.09% for Li, 2.81% for Na), indicating its “zero-strain” properties with stable cycling performance. Li⁺ and Na⁺ can diffuse along the channels inside the Si₂₄ structure with barrier energies of 0.14 and 0.80 eV respectively, and the ionic conductivity of Li_2.66Si₂₄ was calculated to be as high as 1.03 × 10⁻¹ S cm⁻¹ at 300 K. Our calculations indicate that the fast Li-ionic conductivity properties make the Si₂₄ structure a novel anode material for both lithium and sodium ion batteries.

Systematic investigation of Si₂₄ for Li/Na ion batteries using first-principles methods.     

兔肝VX2瘤血供程度对HIFU作用效果影响的初步研究

目的 探讨兔肝VX2瘤实质期血供程度对高能聚焦超声(HIFU)后肿瘤靶点处温度及凝固性坏死体积(V)大小的影响,为进一步精确控制HIFU剂量、提高治疗效率提供实验依据.方法 制作瘤兔24只并分成:10、15、20 d、无血供组(10 d成模后处死)4组,在对应时间进行相同参数HIFU辐照,对靶点实时测温,做出时间-温度曲线(TTC),测量V,对坏死周边残存肿瘤组织及正常肝组织进行微血管密度(MVD)计数.结果 (1)肿瘤MVD:10 d组＞15 d组＞20 d组(P＜0.05).(2)峰值温度(Tmax)、峰值时间(T1)、温升斜率(k1):10 d组、15 d组、20 d组之间比较差异无统计学意义(P＞0.05),此三组与无血供组比较差异有统计学意义(P＜0.05).(3)温降斜率(k2):10 d组＞15d组＞20 d组＞无血供组(P＜0.05);温降时间(T2):10 d组＜15 d组＜20 d组＜无血供组(P＜0.05);(4)V:10 d组＜15 d组＜20 d组＜无血供组(P＜0.05).结论 肿瘤血供程度对HIFU“温升”过程无显著影响,而对“冷却”过程有显著的影响.肿瘤血供越丰富,辐照后散热越快,组织越易恢复到正常温度,形成V越小.     

Folate Deficiency Decreases Apoptosis of Endometrium Decidual Cells in Pregnant Mice via the Mitochondrial Pathway

It is well known that maternal folate deficiency results in adverse pregnancy outcomes. In addition to aspects in embryonic development, maternal uterine receptivity and the decidualization of stromal cells is also very important for a successful pregnancy. In this study, we focused on endometrium decidualization and investigated whether apoptosis, which is essential for decidualization, was impaired. Flow cytometry and TUNEL detection revealed that apoptosis of mouse endometrium decidual cells was suppressed in the dietary folate-deficient group on Days 7 and 8 of pregnancy (Day 1 = vaginal plug) when decidua regression is initiated. The endometrium decidual tissue of the folate deficiency group expressed less Bax compared to the normal diet group while they had nearly equal expression of Bcl2 protein. Further examination revealed that the mitochondrial transmembrane potential (ΔΨm) decreased, and the fluorescence of diffuse cytoplasmic cytochrome c protein was detected using laser confocal microscopy in normal decidual cells. However, no corresponding changes were observed in the folate-deficient group. Western blotting analyses confirmed that more cytochrome c was released from mitochondria in normal decidual cells. Taken together, these results demonstrated that folate deficiency could inhibit apoptosis of decidual cells via the mitochondrial apoptosis pathway, thereby restraining decidualization of the endometrium and further impairing pregnancy.     

Theoretical investigations on azole-fused tricyclic 1,2,3,4-tetrazine-2-oxides

Fused compounds, a unique class of large conjugate structures, have emerged as prime candidates over traditional nitrogen-rich mono-ring or poly-ring materials. Meanwhile, compounds containing catenated nitrogen chains have also attracted attention from scientists due to their high heats of formation. On the other hand, the azoxy [–N N(O)–] moiety has been found to increase density effectively in the molecular structure of compounds. Therefore, combining fused heterocyclic organic skeletons with the azoxy moiety can be regarded as an effective method for increasing the density and heat of formation, which results in substantial increase in detonation properties. Based on the above-mentioned considerations, in this study, a series of new non-hydrogen-containing 5/6/5 fused ring molecules with azoxy moiety structures are designed. Furthermore, their properties as potential high-energy-density materials, including their density, heats of formation, detonation properties, and impact sensitivity, have been extensively evaluated using thermodynamic calculations and density functional theory. Among the investigated compounds, 1,3,8,10-tetranitrodiimidazo[1,5-d:5′,1′-f][1,2,3,4]tetrazine 5-oxide (B), 1,10-dinitrobis([1,2,3]triazolo)[1,5-d:5′,1′-f][1,2,3,4]tetrazine 5-oxide (C) and 2,9-dinitrobis([1,2,4]triazolo)[1,5-d:5′,1′-f][1,2,3,4]tetrazine 5-oxide (D) display remarkable stabilities and are predicted to be high-performance energetic materials due to their high density (>1.94 g cm⁻³), detonation velocity (>9616 m s⁻¹), and detonation pressure (>41.1 GPa). In addition, our design strategy, which combines the azoxy moiety and fused tricyclic skeleton to construct nitrogen-rich molecular structures with high density and positive heat of formation, is a valuable approach for developing novel high-energy-density materials with excellent performance and stability.

In this work, a series of novel non-hydrogen-containing 5/6/5 fused ring molecules with azoxy moiety were designed, some physicochemical or detonation properties of them were calculated.     

The Angiopoietin-like protein 4: a promising biomarker to distinguish brucella spondylitis from tuberculous spondylitis

Clinical Rheumatology - The Angiopoietin-like protein 4 (ANGPTL-4) has been proved to be a protein associated with multiple inflammatory responses. Nevertheless, whether it contributes to...     

Successful management of lung adenocarcinoma with ALK/EGFR co-alterations and PD-L1 over-expression by bevacizumab combined with chemotherapy

Angiogenesis - Anaplastic lymphoma kinase (ALK)/epidermal growth factor receptor (EGFR) co-alterations in adenocarcinomas are rare and no therapeutic consensus is reached. The potentially negative...     

Vascular-specific epicardial adipose tissue in predicting functional myocardial ischemia for patients with stable chest pain

Journal of Thrombosis and Thrombolysis - The relationship between vascular-specific epicardial adipose tissue (vEAT) volume and myocardial ischemia measured by fractional flow reserve (FFR) was not...