Bi-doping improves the magnetic properties of zinc oxide nanowires

Room-temperature ferromagnetism in the large and direct bandgap diluted magnetic semiconductor zinc oxide (ZnO) is attributed to the intrinsic defects and p-orbital–p-orbital (p–p) coupling interaction. However, due to oxidation, the ferromagnetism induced by defects is unstable. In the present work, the solution process synthesis route was utilized to grow pristine and bismuth-doped, highly crystalline ZnO nanowire (ZnO NW)-based samples. The FE-SEM images showed that the grown ZnO NWs have a preferred orientation along the c-axis in the (001) direction due to the anisotropic crystal nature of ZnO. X-ray photoelectron spectroscopy (XPS) confirmed the presence of Bi, and at a higher doping content, the bismuth oxide phase appeared. The XRD patterns showed the wurtzite crystal structure, and the large intensity of the (002) peak suggests that most of the reflection was from the top hexagonal face of the NWs, and thus, the wires are predominantly aligned along the c-axis. The TEM analysis further confirmed the crystal growth direction along the (001) direction. The UV-Visible absorption and PL measurements also showed a decrease in the bandgap with an increase in doping concentration, which may be associated with the sp–d exchange interaction between the localized d-electrons and band electrons of the Bi ions. Bi-doping tended to increase the PL intensity in the visible region. The magnetic properties measured by SQUID at 4 and 300 K showed ferromagnetic behaviour for both the pristine and Bi-doped samples. However, the saturation magnetization for the Bi-doped samples was higher compared to that of the pristine ZnO samples until the threshold doping value. The obtained results demonstrated that Bi-doping can be used to tune both the optical and magnetic properties of ZnO NWs, hence paving the way for future spintronics and spin-polarized optoelectronics applications.

Room-temperature ferromagnetism in the large and direct bandgap diluted magnetic semiconductor zinc oxide (ZnO) is attributed to the intrinsic defects and p-orbital–p-orbital (p–p) coupling interaction.     

Anti‐fibrosis effect of BMP‐7 peptide functionalization on cobalt chromium alloy

Orthopedic metallic prosthetic implants are commonly made of cobalt chromium (CoCr) alloys. However, such metal‐based implants are susceptible to fibrous capsule formation on the implant surface after implantation. At the bone‐implant interface, this capsule can prevent implant integration, resulting in loosening and failure. Minimizing the development of such a capsule on the CoCr surface would improve direct bone‐implant bonding leading to long‐term implant functionality. We evaluated the anti‐fibrosis effect of bone morphogenic protein‐7 (BMP‐7) peptide covalently bonded to CoCr alloy. This peptide, a biomimetic derivation of the knuckle epitope of BMP‐7, was conjugated at the N‐terminus with a cysteine amino acid. X‐ray photoelectron spectroscopy (XPS) and probe binding assay were used to evaluate different stages of grafting and surface functionalization using polydopamine coating. Cellular functions were studied using fibroblast attachment, cell proliferation, and MTT assays. Fibroblasts were grown on functionalized and pristine CoCr substrates, and the efficacy of BMP‐7 peptide on anti‐fibrosis was analyzed via gene expression and protein expression of fibrosis markers ACTA2, Collagen 1A1, and fibronectin. The peptide functionalized substrates showed significant reduction of fibrosis markers expression after 1 week of incubation compared to controls. BMP‐7 signaling pathway activation was shown by the presence of phosphorylation of Smad1/5/8. These findings may contribute to the improvement of CoCr implants in orthopedic surgery applications. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 983–990, 2013     

MicroRNAs in an oral cancer context - from basic biology to clinical utility

Oral cancer is one of the most commonly diagnosed malignancies worldwide. Its dismal five-year survival rate of ~50% has barely changed for decades. A better understanding of the molecular basis of tumorigenesis - with particular emphasis on disease initiation and progression - is needed to improve clinical outcomes, since this will facilitate the development of drugs and management strategies based on the specific genetic changes underpinning disease behaviors. MicroRNAs (miRNAs), a class of short non-coding RNAs that down-regulate gene expression, have been demonstrated to play essential roles in human cancers. miRNA deregulation has been observed in many tumor types and is implicated in oncogenic cell processes, including proliferation, survival, apoptosis, metastasis, and chemoresistance. In addition, miRNA alterations have been associated with specific clinical phenotypes such as disease progression or recurrence, development of metastases, and post-operative survival. Recent studies have explored the utility of miRNAs as diagnostic and prognostic tools and as potential therapeutic targets. Herein, we discuss miRNA biology and provide a summary of the key findings on the role of miRNAs in oral malignancies.     

Parental Feeding Practices and Child-Related Factors are Associated with Overweight and Obesity in Children and Adolescents with Autism Spectrum Disorder

Journal of Autism and Developmental Disorders - Atypical eating behaviors displayed by children with autism spectrum disorder (ASD) predispose them to unhealthy weight gain. We determined the...     

Identification of neutralizing linear epitopes from the VP1 capsid protein of Enterovirus 71 using synthetic peptides

Enterovirus 71 (EV71) is the main causative agent of Hand, foot and mouth disease (HFMD) and has been associated with severe neurological diseases resulting in high mortalities. Currently, there is no vaccine available and treatment is limited to palliative care. In this study, antisera were raised in mice against 95 overlapping synthetic peptides spanning the VP1 capsid protein of EV71. Two peptides, SP55 and SP70, containing amino acid 163-177 and 208-222 of VP1, respectively, are capable of eliciting neutralizing antibodies against EV71 in the in vitro microneutralization assay. SP70 was identified to be particularly potent in eliciting a neutralizing antibody titer comparable to that obtained with a whole virion-immune serum. Immunization of mice with either SP55 or SP70 triggered an EV71-specific IgG response as high as that obtained with the whole virion as immunogen. The IgG sub-typing revealed that the neutralizing antibodies elicited by both synthetic peptides are likely belonging to the IgG1 sub-type. Alignment with databases showed that the amino acid residues of SP70 are highly conserved amongst the VP1 sequences of EV71 strains from various sub-genogroups. Altogether, these data indicate that SP70 represents a promising candidate for an effective synthetic peptide-based vaccine against EV71.