The uniform growth of single-crystal graphene over wafer-scale areas remains a challenge in the commercial-level manufacturability of various electronic, photonic, mechanical, and other devices based on graphene. Here, we describe wafer-scale growth of wrinkle-free single-crystal monolayer graphene on silicon wafer using a hydrogen-terminated germanium buffer layer. The anisotropic twofold symmetry of the germanium (110) surface allowed unidirectional alignment of multiple seeds, which were merged to uniform single-crystal graphene with predefined orientation. Furthermore, the weak interaction between graphene and underlying hydrogen-terminated germanium surface enabled the facile etch-free dry transfer of graphene and the recycling of the germanium substrate for continual graphene growth.

No abstract

RNA-binding proteins (RBPs) and microRNAs (miRNAs) are potent post-transcriptional regulators of gene expression. Here, we show that the RBP HuR reduced c-Myc expression by associating with the c-Myc 3′ untranslated region (UTR) next to a miRNA let-7-binding site. Lowering HuR or let-7 levels relieved the translational repression of c-Myc. Unexpectedly, HuR and let-7 repressed c-Myc through an interdependent mechanism, as let-7 required HuR to reduce c-Myc expression and HuR required let-7 to inhibit c-Myc expression. Our findings suggest a regulatory paradigm wherein HuR inhibits c-Myc expression by recruiting let-7-loaded RISC (RNA miRNA-induced silencing complex) to the c-Myc 3′UTR.

Finding a needle in a haystack: A new technology is demonstrated to enrich circulating tumor cells (CTCs) with high efficiency by integrating an antibody‐coated silicon nanopillar (SiNP, see picture; gray) substrate with an overlaid polydimethylsiloxane (PDMS) microfluidic chaotic mixer (turquoise). It shows significantly improved sensitivity in detecting rare CTCs from whole blood, thus providing an alternative for monitoring cancer progression.

No abstract

BACKGROUND:The effects of the BRAF V600E mutation on prognostic factors and poor clinical outcomes in papillary thyroid cancer (PTC) have not been fully quantified. The authors performed comprehensive meta-analysis to assess the strength of associations between these conditions and the BRAF V600E mutation. METHODS: The authors identified the clinical studies that examined the association of the BRAF V600E mutation in surgical specimens with clinicopathologic outcomes between January 2003 and October 2010 using the Medline database. One hundred thirty-one relevant studies were hand-searched. The authors selected 27 studies that included 5655 PTC patients. They calculated the pooled odds ratios (ORs) or risk ratios with 95% confidence intervals (CIs) for each study using a random effect model. RESULTS: The average prevalence rate of the BRAF V600E mutation was 49.4%. In 26 studies, compared with the patients who had the wild-type BRAF genes, the PTC patients with the BRAF V600E mutation had increasedORs of an extrathyroidal invasion (OR, 2.14; 95% CI, 1.68-2.73), a lymph node metastasis (OR, 1.54; 95% CI, 1.21-1.97), and an advanced TNM stage (OR, 2.00; 95% CI, 1.61-2.49). In 8 studies, patients with the mutation had 2.14-fold increased risk of recurrent and persistent disease (95% CI, 1.67-2.74). The associations were generally consistent across the different study populations. CONCLUSIONS: This meta-analysis demonstrates that the BRAF V600E mutation is closely related to the high-risk clinicopathological factors and poorer outcome of PTC. The results obtained here suggest that the BRAF V600E mutation should be considered as a poor prognostic marker in PTC and may lead to better management for individual patients.

Adipose tissue development is tightly regulated by altering gene expression. MicroRNAs are strong posttranscriptional regulators of mammalian differentiation. We hypothesized that microRNAs might influence human adipogenesis by targeting specific adipogenic factors. We identified microRNAs that showed varying abundance during the differentiation of human preadipocytes into adipocytes. Among them, miR-130 strongly affected adipocyte differentiation, as overexpressing miR-130 impaired adipogenesis and reducing miR-130 enhanced adipogenesis. A key effector of miR-130 actions was the protein peroxisome proliferator-activated receptor ␥ (PPAR␥), a major regulator of adipogenesis. Interestingly, miR-130 potently repressed PPAR␥ expression by targeting both the PPAR␥ mRNA coding and 3 untranslated regions. Adipose tissue from obese women contained significantly lower miR-130 and higher PPAR␥ mRNA levels than that from nonobese women. Our findings reveal that miR-130 reduces adipogenesis by repressing PPAR␥ biosynthesis and suggest that perturbations in this regulation is linked to human obesity.

Piezomaterials are known to display enhanced energy conversion efficiency at nanoscale due to geometrical effect and improved mechanical properties. Although piezoelectric nanowires have been the most widely and dominantly researched structure for this application, there only exist a limited number of piezomaterials that can be easily manufactured into nanowires, thus, developing effective and reliable means of preparing nanostructures from a wide variety of piezomaterials is essential for the advancement of self-powered nanotechnology. In this study, we present nanoporous arrays of polyvinylidene fluoride (PVDF), fabricated by a lithography-free, template-assisted preparation method, as an effective alternative to nanowires for robust piezoelectric nanogenerators. We further demonstrate that our porous PVDF nanogenerators produce the rectified power density of 0.17 mW/cm3 with the piezoelectric potential and the piezoelectric current enhanced to be 5.2 times and 6 times those from bulk PVDF film nanogenerators under the same sonic-input.