Long-Acting Antibacterial Hydrogels Constructed by Interface-Induced Directional Assembly.

Self-assembled supermolecular hydrogels of therapeutic agents without structural modification are of great significance in biomedical applications. Nevertheless, the complex conformations and elusive interactions of therapeutic molecules limit the controlled assembly of hydrogels. Molecules at the interface might have different arrangements and assemblies compared to those in bulk aqueous solution, which could potentially alter the selectivity of supramolecular polymorphs. However, this effect is still not well understood. Here, we demonstrate the interface-induced self-assembly of fibers for hydrogels, which is distinct from the spherical aggregates in the bulk aqueous solution, using cephradine (CEP) as a model compound. This phenomenon is caused by the packing of anisotropic molecules at the interface, and it can be applied to control the supramolecular polymorphism for the direct self-assembly of hydrogels of therapeutic agents. The interface-induced hydrogel exhibits a high degree of adjustable release and a long-acting bactericidal effect.

Revealing the Molecular Mechanism of Cosolvency Based on Thermodynamic Phase Diagram, Molecular Simulation, and Spectrum Analysis: The Tolbutamide Case.

Cosolvency has been observed in many systems. To reveal the mechanism of cosolvency from the molecular level, the effects of molecular conformation, supramolecular clusters, and interactions on cosolvency were systematically investigated using tolbutamide as a model compound, through experimental exploration, spectral detection, and molecular simulation. The results show that, under the influence of intermolecular and intramolecular interactions, the dominant solute molecular conformations transform and the supramolecular clusters change in different solution systems, which then lead to the cosolvency phenomena.

ATR and BRCA2 Simultaneous Mutation in a ccRCC With Sarcomatoid Differentiation and Extensive Metastases: A Case Report.

The genomic landscape and driver-gene mutations differ significantly among diverse histological subtypes of clear cell renal cell carcinoma (ccRCC) due to the intratumoral heterogeneity. Frequent mutations in canonical DNA damage response genes, such as BRCA1/2 or ATR serine/threonine kinase (ATR) haven't been reported even in large-scale genomic profiling of ccRCC researches. Herein, we reported a rare ccRCC harboring ATR and BRCA2 simultaneous mutation with complicated morphologies and extensive metastases. Our case indicates that the deleterious alteration of DNA damage response genes, increasing CD8+ TILs, high PD1/PD-L1 expression and high TMB might contribute to this patient's tumor metastasis and aggressive biological behavior.

Urea-induced supramolecular self-assembly strategy to synthesize wrinkled porous carbon nitride nanosheets for highly-efficient visible-light photocatalytic degradation.

Graphitic carbon nitride (g-C3N4) has attracted immense interest as a promising photocatalyst. To facilitate its versatile applications in many fields, new low-cost strategies to synthesize outstanding g-C3N4 need to be further developed. Although supramolecular preorganization has been considered as a promising candidate, the utilized supramolecules like melamine-cyanuric acid (MCA) are typically synthesized by expensive triazine derivatives. Herein, wrinkled porous g-C3N4 nanosheets were successfully fabricated by hydrothermal-annealing of supramolecular intermediate MCA synthesized by the cheap precursors dicyandiamide and urea. During the formation of MCA, urea could act as a facile agent to react with dicyandiamide to form melamine and cyanuric acid firstly and then assemble into MCA through hydrogen bonds. In addition, urea could serve as a porogen and decompose to generate bubbles for conducive formation of micro-size MCA self-templates and thus wrinkled porous g-C3N4 nanosheets could be obtained. The nanostructure and photocatalytic performance of g-C3N4 were optimized by modulating microstructures and physicochemical properties of MCA, which could be conveniently controlled by urea addition and hydrothermal duration. The obtained wrinkled porous g-C3N4 nanosheets exhibit highly-efficient visible-light photocatalytic degradation compared with traditional MCA-derived g-C3N4, which could remove 98.3% of the rhodamine B in 25 min. The superior photocatalytic activity is mainly attributed to the urea-induced larger specific surface area, better light harvesting ability, faster transfer and more advanced separation efficiency of the photogenerated electron-hole pairs. This research provides a new strategy for preparing high-performance porous g-C3N4 from the self-assembled supramolecule MCA synthesized by low-cost precursors.

Molecular conformational evolution mechanism during nucleation of crystals in solution.

Nucleation of crystals from solution is fundamental to many natural and industrial processes. In this work, the molecular mechanism of conformational polymorphism nucleation and the links between the molecular conformation in solutions and in crystals were investigated in detail by using 5-nitro-furazone as the model compound. Different polymorphs were prepared, and the conformations in solutions obtained by dissolving different polymorphs were analysed and compared. The solutions of 5-nitro-furazone were proven to contain multiple conformers through quantum chemical computation, Raman spectra analysis, 2D nuclear Overhauser effect spectroscopy spectra analysis and molecular dynamics simulation. The conformational evolution and desolvation path was illustrated according to the 1H NMR spectra of solutions with different concentrations. Finally, based on all the above analysis, the molecular conformational evolution path during nucleation of 5-nitro-furazone was illustrated. The results presented in this work shed a new light on the molecular mechanism of conformational polymorphism nucleation in solution.

[Signal intensity-time curve and quantitative dynamic contrast-enhanced magnetic resonance imaging in differentiating neoplasms of uterus].

OBJECTIVE: To evaluate signal intensity-time (SI-Time) curve and quantitative dynamic contrast-enhanced 3.0T magnetic resonance imaging in diagnosis and differentiating neoplasm of uterus.
 METHODS: A total of 42 cases of uterine neoplasm (20 were malignant and 22 were benign) were evaluated in our study. All cases received dynamic contrast-enhanced scanning on 3.0T MRI. The raw data was processed by Siemens Tissue 4D software and the SI-Time curve was obtained and analyzed. Pharmacokinetic modeling of Tofts with a modeled vascular input function was used for calculating volume parameters: volume transfer constant (Ktrans), reverse volume transfer constant (Kep), the extravascular extracellular space volume per unit volume of tissue (Ve). The correlation of these parameters at each groups were investigated. The SI-Time curve and the data of perfusion parameters between the 2 groups were compared by T test.
 RESULTS: Among 20 malignant tumors, 12 were cervical carcinoma and 8 were endometrial cancer. Among the benign tumors, 13 were leiomyomas, 3 were endometrial polyp, 3 were endometrial hyperplasia, and 3 were adenomyosis. 59.1% cases of benign tumors belong to Type I curve and 65% cases of malignant tumors belong to Type II curve. There was significant difference in SI-Time curve between benign and malignant tumors (P=0.011). If Type I curve was used as diagnostic criteria for benign tumors, and Type II and III curve were for malignant tumors, the diagnostic sensitivity, specificity, positive predictive value, negative predictive value were 90.0%, 59.1%, 66.7%, and 86.7%, respectively. Ve was 0.477 ± 0.143 in malignant and 0.614 ± 0.146 in control group with significant difference (P=0.004). Ve was 0.477 ± 0.143 in malignant and 0.589 0.176 in benign group with significant difference (P=0.004). Ktrans was (0.178 ± 0.067) min⁻¹ in malignant and (0.263 ± 0.111) min⁻¹ in control group with significant difference (P=0.003). Ktrans was (0.182 ± 0.096) min⁻¹ in benign and (0.263 ± 0.111) min⁻¹ in control group with significant difference (P=0.011). 
 CONCLUSION: The type of SI-Time curve and perfusion parameters were important for differentiating benign and malignant uterine tumors in dynamic enhanced MRI. These parameters provide a supplement for conventional morphological MR diagnosis.

Differentiation of central lung cancer from atelectasis: comparison of diffusion-weighted MRI with PET/CT.

OBJECTIVE: Prospectively assess the performance of diffusion-weighted magnetic resonance imaging (DW-MRI) for differentiation of central lung cancer from atelectasis. MATERIALS AND METHODS: 38 consecutive lung cancer patients (26 males, 12 females; age range: 28-71 years; mean age: 49 years) who were referred for thoracic MR imaging examinations were enrolled. MR examinations were performed using a 1.5-T clinical scanner and scanning sequences of T1WI, T2WI, and DWI. Cancers and atelectasis were measured by mapping of the apparent diffusion coefficients (ADCs) obtained with a b-value of 500 s/mm(2). RESULTS: PET/CT and DW-MR allowed differentiation of tumor and atelectasis in all 38 cases, but T2WI did not allow differentiation in 9 cases. Comparison of conventional T2WI and DW-MRI indicated a higher contrast noise ratio of the central lung carcinoma than the atelectasis by DW-MRI. ADC maps indicated significantly lower mean ADC in the central lung carcinoma than in the atelectasis (1.83±0.58 vs. 2.90±0.26 mm(2)/s, p<0.0001). ADC values of small cell lung carcinoma were significantly greater than those from squamous cell carcinoma and adenocarcinoma (p<0.0001 for both). CONCLUSIONS: DW-MR imaging provides valuable information not obtained by conventional MR and may be useful for differentiation of central lung carcinoma from atelectasis. Future developments may allow DW-MR imaging to be used as an alternative to PET-CT in imaging of patients with lung cancer.