RESUMO
Heterointerface engineering for different identifiable length scales has emerged as a key research area for obtaining materials capable of high-performance electromagnetic wave absorption; however, achieving controllable architectural and compositional complexity in nanomaterials with environmental and thermal stabilities remains challenging. Herein, metal-containing silicon carbonitride (SiCN/M) nanocomposite ceramics with multiphase heterointerfaces were in situ synthesized via coordination crosslinking, catalytic graphitization, and phase separation processes using trace amounts of metal-organic frameworks (MOFs). The results reveal that the regulation of dielectric genes by MOFs can yield considerable lattice strain and abundant lattice defects, contributing to strong interfacial and dipole polarizations. The as-prepared SiCN/M ceramics demonstrate excellent microwave absorption performance: the minimum reflection loss (RLmin ) is -72.6 dB at a thickness of only 1.5 mm and -54.1 dB at an ultralow frequency of 3.56 GHz for the SiCN/Fe ceramics and the RLmin is -55.1 dB with a broad bandwidth of 3.4 GHz at an ultralow thickness of 1.2 mm for the SiCN/CoFe ceramic. The results are expected to provide guidance for the design of future dielectric microwave absorption materials based on heterointerface engineering while offering a paradigm for developing MOF-modified SiCN nanocomposite ceramics with desirable properties.
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The development of a rapid and sensitive detection platform for DNA and DNA methylation in complex biological environments has attracted considerable attention. Herein, we describe a detection platform for p16 and p16 methylation in buffer and serum based on a single polymeric fluorescent microfiber waveguide with sandwich-structured hybridization designs. The target p16 could be captured by oligonucleotides conjugated on the surface of polymeric microfibers and oligonucleotides conjugated with gold nanoparticles, resulting in quenching the out-coupled tip emission of the microfiber waveguide. Then the restriction digestion enzyme HpaII was applied to specifically recognize the unmethylated 5'-CCGG-3' site and cut the formed sandwich structure. The gold nanoparticles could be removed from the surface of chitosan fiber so that the out-coupled tip emission of the polymeric fluorescent microfiber would be partially recovered. It is noteworthy that the proposed polymeric microfiber waveguide platform exhibited selective and sensitive detection of p16 with a low limit of 2 pM and excellent analytical performance of methylation as low as 5% difference. This strategy avoids the use of traditional PCR-based amplification and tedious operative processes, and we envisage that this technique could be extended to various DNA methylation analyses, which is meaningful for early clinical diagnosis of diseases.
Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Técnicas Biossensoriais/métodos , Metilação de DNA , Ouro/química , Nanopartículas Metálicas/química , Oligonucleotídeos , Polímeros/químicaRESUMO
Graphene-based aerogels have garnered considerable attention for their lightweight and efficient microwave absorption (MA) properties; however, optimizing the relationship between impedance matching and attenuation capability at low frequencies remains a challenge. In this study, a three-dimensional (3D) silicon carbonitride (SiCN) nanoceramic-coated graphene aerogel with conformal heterogeneous interfaces is constructed by precursor infiltration and pyrolysis to optimize MA performance at low frequencies. Thanks to the enhanced impedance matching and significant interfacial polarization of the two-dimensional sandwiched SiCN/graphene/SiCN cell walls and multiple scattering occurring within the 3D porous skeleton, the aerogel achieves a minimum reflection loss of -57.9 dB at an ultralow frequency of 4.92 GHz (C-band) and a broad bandwidth of 5.0 GHz at an ultralow thickness of 1.7 mm. The strategy developed here provides a method for enhancing dielectric polarization loss in graphene aerogels by the joint optimization of interfacial polarization and impedance matching, inspiring the design of high-performance graphene-based materials for low-frequency MA.
RESUMO
The symmetry in a polymorph is one of the most important elements for determining the inherent lattice nature. The MnO2 host tends to high-symmetry MnO6 octahedra as a result of the electronic structure t2g 3 eg 0 of Mn4+ ions, displaying an ordered structure accompanying with poor polarization loss and limiting its application toward high-performance microwave absorbers. Here, a pseudo-Jahn-Teller (PJT) distortion and PJT disordering design with abundant self-forming interfaces and local magnetic domains in the monoclinic birnessite-MnO2 host is first reported. The PJT distortion can give rise to asymmetric MnO6 octahedra, inducing the formation of interfaces and increased electron spin magnetic moment in the lattice. The resultant birnessite with PJT distortions and PJT disordering delivers an outstanding reflection loss value of -42.5 dB at an ultralow thickness of 1.7 mm, mainly derived from the excited interfacial polarization and magnetic loss. This work demonstrates an effective approach in regulating the lattice structure of birnessite for boosting microwave absorption performance.
RESUMO
We have successfully carried out single-hole inflator-free endoscopic thyroidectomy through a submental approach, which has the advantages of less trauma, fewer complications, and hidden incisions. However, for patients with submandibular fat accumulation, submental incisions are not easy to hide, which directly affects the cosmetic effect. We developed a new surgical strategy "submandibular suction lipectomy and single-hole inflator-free endoscopic thyroidectomy with a submental approach" for these patients. We initially used submandibular suction lipectomy to reduce the accumulation of submandibular fat and obvious fat protrusion and, thus, restore the normal depression, placing the submental incision back where it is hidden in the submental shadow. Subsequentially, we began to use single-hole inflator-free endoscopic thyroidectomy with a submental approach. We aimed to explore the feasibility and cosmetic effect of this method for the treatment of thyroid disease patients with submandibular fat accumulation. The average operation time was 4.2 hours; and the average hospitalization time was 4.75 days. There were no postoperative complications, such as hoarseness, low calcium, hand and foot numbness, etc., and no special complications and no recurrence or metastasis seen in the 6-month follow-up examination. The aesthetic satisfaction survey results of patients half a year after surgery were satisfactory and above. For thyroid cancer patients with submandibular fat accumulation, this method not only hides the surgical incision in the neck but also meets the patient's requirement for "submental aesthetics"; thus it has good application prospects. It should be pointed out that the current findings are preliminary results, based on data from only four patients.
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Objectives: To evaluate the potential improvement of prediction performance of a proposed double branch multimodality-contribution-aware TripNet (MCAT) in microvascular invasion (MVI) of hepatocellular carcinoma (HCC) based on a small sample. Methods: In this retrospective study, 121 HCCs from 103 consecutive patients were included, with 44 MVI positive and 77 MVI negative, respectively. A MCAT model aiming to improve the accuracy of deep neural network and alleviate the negative effect of small sample size was proposed and the improvement of MCAT model was verified among comparisons between MCAT and other used deep neural networks including 2DCNN (two-dimentional convolutional neural network), ResNet (residual neural network) and SENet (squeeze-and-excitation network), respectively. Results: Through validation, the AUC value of MCAT is significantly higher than 2DCNN based on CT, MRI, and both imaging (P < 0.001 for all). The AUC value of model with single branch pretraining based on small samples is significantly higher than model with end-to-end training in CT branch and double branch (0.62 vs 0.69, p=0.016, 0.65 vs 0.83, p=0.010, respectively). The AUC value of the double branch MCAT based on both CT and MRI imaging (0.83) was significantly higher than that of the CT branch MCAT (0.69) and MRI branch MCAT (0.73) (P < 0.001, P = 0.03, respectively), which was also significantly higher than common-used ReNet (0.67) and SENet (0.70) model (P < 0.001, P = 0.005, respectively). Conclusion: A proposed Double branch MCAT model based on a small sample can improve the effectiveness in comparison to other deep neural networks or single branch MCAT model, providing a potential solution for scenarios such as small-sample deep learning and fusion of multiple imaging modalities.