Graphene-based polystyrene (PS) nanocomposites were prepared by latex mixing, co-coagulation, and in situ reduction process. In the process, aqueous dispersion of graphene oxide (GO) was mixed with ...PS latex, which was then co-coagulated with sodium chloride to form stabilized particle suspension; subsequently, hydrazine hydrate was added to reduce GO in situ. This process could avoid the use of additional surfactant or ultrasonic power to stabilize graphene during reduction, thus is facile and energy saving. The preparation process and the resulting nanocomposites were characterized in detail. The results show that, after co-coagulation, GO nanosheets are isolated by PS nanospheres through π–π interaction, which prevents the restacking of graphene in the subsequent reduction process. Thus, a molecular-level dispersion of the graphene nanosheets in the PS matrix is achieved, which greatly improves the electrical conductivity and the mechanical properties of the nanocomposites.
Many high-strength hydrogels have been developed in recent years; however, few of them are both tough and resilient, and their intrinsic paradoxical nature makes designing a gel with both high ...toughness and high resilience a great challenge. To address this problem, we introduced both N,N,N,N-pentamethyldiethylenetriamine (PA) and N,N-methylenebisacrylamide (MBA) into polyacrylamide hydrogel networks to construct an entangled network that contains chemically cross-linked chains and branched chains simultaneously. The entanglements of branched chains can act as a physical cross-linking point to uniformly disperse stress on molecular chains, and chemical cross-linking ensures the stability of the hydrogel network. The increase in the number and length of branched chains is able to achieve an enhancement in strength while the slip of the entangled polymer chains can effectively achieve energy dissipation and can improve the toughness of the gel. Moreover, the resultant hydrogels exhibit an excellent resilience (>98%). Therefore, high toughness and resilience are achieved simultaneously. In addition, we also investigated the initiation mechanism of PA. This strategy creates a new way for the preparation of next-generation high toughness and high resilience hydrogel-based materials, which have promising applications in wearable, flexible strain/pressure sensors.
Ischemic stroke (IS) is one of the leading causes of disability and mortality worldwide. This study aims to find the crucial exosomal miRNAs associated with IS by using bioinformatics methods, reveal ...potential biomarkers for IS, and investigate the association between the identified biomarker and immune cell pattern in the peripheral blood of IS patients. In this study, 3 up-regulated miRNAs (hsa-miR-15b-5p, hsa-miR-184, and hsa-miR-16-5p) miRNAs in the serum exosomes between IS patients and healthy controls from GEO database (GSE199942) and 25 down-regulated genes of peripheral blood mononuclear cells of IS patients from GSE22255 were obtained with the help of the R software. GO annotation and KEGG pathway enrichment analysis showed that the 25 down-regulated genes were associated with coenzyme metabolic process and were mainly enriched in the N-glycan biosynthesis pathway. Furthermore, we performed the LASSO algorithm to narrow down the above 25 intersected genes, and identified 8 key genes which had a good diagnostic value in discriminating IS patients from the healthy controls analyzed with ROC curve. CIBERSORT algorithm indicated that the abundance of M0 macrophages and resting mast cells was significantly lower than that of the control group. The spearman correlation analysis showed that STT3A was negatively correlated with the proportion of follicular helper T cells, activated NK cells and resting dendritic cells. Finally, GSE117064 showed that has-miR-16-5p was more advantageous for diagnosing stroke. In conclusion, hsa-miR-15b-5p, hsa-miR-184, and hsa-miR-16-5p are identified as specific related exosomal miRNAs for IS patients. These genes may provide new targets for the early identification of IS.
Daptomycin, which is produced by
Streptomyces roseosporus
, has been characterized as a novel cyclic lipopeptide antibiotic that is effective against Gram-positive bacteria. The biosynthesis of ...daptomycin is regulated by various factors. In the present study, we demonstrated that the cyclic AMP receptor protein (Crp) plays an important role in producing daptomycin in the
S. roseosporus
industrial strain. We found that daptomycin production from the
crp
deletion strain decreased drastically, whereas production from the
crp
overexpression strain increased by 22.1%. Transcriptome and qPCR analyses showed that some genes related to the daptomycin biosynthetic gene cluster (
dpt
) and the pleiotropic regulator (
adpA
) were significantly upregulated. RNA-seq also shows Crp to be a multifunctional regulator that modulates primary metabolism and enhances precursor flux to secondary metabolite biosynthesis. These results provide guidance for the development and improvement of potential natural products.
Colon cancer is a complex, heterogeneous disease. The Colorectal Cancer Subtyping Consortium reported a novel classification system for colon cancer in 2015 to better understand its heterogeneity. ...This molecular classification system divided colon cancer into four distinct consensus molecular subtypes (CMS 1, 2, 3, and 4). However, the characteristics of different colon cancer molecular subtypes have not been fully elucidated. This study comprehensively analyzed the molecular characteristics of varying colon cancer subtypes using multiple databases and algorithms, including The Cancer Genome Atlas (TCGA) database, DriverDBv3 database, CIBERSORT, and MCP-counter algorithms. We analyzed the alterations in the subtype-specific genes of different colon cancer subtypes, such as the RNA levels and DNA alterations, and showed that specific subtype-specific genes significantly affected prognosis. We also explored the changes in colon cancer driver genes and representative genes of 10 signaling pathways in different subtypes. We identified genes that were altered in specific subtypes. We further detected the infiltration of 22 immune cell types in four colon cancer subtypes and the infiltration level of primary immune cells among these subtypes. Additionally, we explored changes in immune checkpoint genes (ICGs) and immunotherapy responses among different colon cancer subtypes. This study may provide clues for the molecular mechanism of tumorigenesis and progression in colon cancer. It also offers potential biomarkers and targets for the clinical diagnosis and treatment of different colon cancer subtypes.
In the present paper, dynamic mechanical properties of poly(n-alkyl acrylates) (PnAA) and poly(n-alkyl methacrylates) (PnAMA) with different alkyl side chain length were studied. The results show ...that with the increase of alkyl side chain length, the storage modulus changes more steadily, and the loss modulus peak and the tan
δ peak become broader for PnAA and PnAMA. At the same time, the tan
δ peak is more and more apart from the loss modulus peak and the point where the storage modulus begins to drop. For quantitative discussion, three variables, the steepness index (
S), the transition wideness (
W) of storage modulus and the integration area (
A) of tan
δ were defined to investigate the potential correlation between the dynamic mechanical properties and alkyl side chain length. It can be observed that
S decreases while
W and
A increase with increasing alkyl side chain length. Moreover, the relaxation spectra of the two series of polymers are calculated from the corresponding mechanical spectra. The shapes of the relaxation spectra are broader and broader with the increase of the alkyl side chain length. These phenomena are interpreted by the perspective of fragility, molecular packing efficiency and intermolecular coupling.
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Although hydrogel is a promising prosthesis implantation material for breast reconstruction, there is no suitable hydrogel with proper mechanical properties and good biocompatibility. Here, we report ...a series of compliant and tough poly (hydroxyethyl methacrylate) (PHEMA)-based hydrogels based on hydrogen bond-reinforcing interactions and phase separation inhibition by introducing maleic acid (MA) units. As a result, the tensile strength, fracture strain, tensile modulus, and toughness are up to 420 kPa, 293.4%, 770 kPa, and 0.86 MJ/m3, respectively. Moreover, the hydrogels possess good compliance, where the compression modulus is comparable to that of the silicone breast prosthesis (~23 kPa). Meanwhile, the hydrogels have an excellent self-recovery ability and fatigue resistance: the dissipative energy and elastic modulus recover almost completely after waiting for 2 min under cyclic compression, and the maximum strength remains essentially unchanged after 1000 cyclic compressions. More importantly, in vitro cellular experiments and in vivo animal experiments demonstrate that the hydrogels have good biocompatibility and stability. The biocompatible hydrogels with breast tissue-like mechanical properties hold great potential as an alternative implant material for reconstructing breasts.
More than one million people acquire sexually transmitted infections (STIs) every day globally. It is possible that predicting an individual's future risk of HIV/STIs could contribute to behaviour ...change or improve testing. We developed a series of machine learning models and a subsequent risk-prediction tool for predicting the risk of HIV/STIs over the next 12 months.
Our data included individuals who were re-tested at the clinic for HIV (65,043 consultations), syphilis (56,889 consultations), gonorrhoea (60,598 consultations), and chlamydia (63,529 consultations) after initial consultations at the largest public sexual health centre in Melbourne from 2 March 2015 to 31 December 2019. We used the receiver operating characteristic (AUC) curve to evaluate the model's performance. The HIV/STI risk-prediction tool was delivered via a web application.
Our risk-prediction tool had an acceptable performance on the testing datasets for predicting HIV (AUC = 0.72), syphilis (AUC = 0.75), gonorrhoea (AUC = 0.73), and chlamydia (AUC = 0.67) acquisition.
Using machine learning techniques, our risk-prediction tool has acceptable reliability in predicting HIV/STI acquisition over the next 12 months. This tool may be used on clinic websites or digital health platforms to form part of an intervention tool to increase testing or reduce future HIV/STI risk.
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