Glassy State Lead Tellurite Nanobelts: Synthesis and Properties

The lead tellurite nanobelts have been first synthesized in the composite molten salts (KNO3/LiNO3) method, which is cost-effective, one-step, easy to control, and performed at low-temperature and in ambient atmosphere. Scanning electron microscopy, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectrum, energy dispersive X-ray spectroscopy and FT-IR spectrum are used to characterize the structure, morphology, and composition of the samples. The results show that the as-synthesized products are amorphous and glassy nanobelts with widths of 200–300 nm and lengths up to tens of microns and the atomic ratio of Pb:Te:O is close to 1:1.5:4. Thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC) and investigations of the corresponding structure and morphology change confirm that the nanobelts have low glass transition temperature and thermal stability. Optical diffuse reflectance spectrum indicates that the lead tellurite nanobelts have two optical gaps at ca. 3.72 eV and 4.12 eV. Photoluminescence (PL) spectrum and fluorescence imaging of the products exhibit a blue emission (round 480 nm)

Cooperativity among Short Amyloid Stretches in Long Amyloidogenic Sequences

Amyloid fibrillar aggregates of polypeptides are associated with many neurodegenerative diseases. Short peptide segments in protein sequences may trigger aggregation. Identifying these stretches and examining their behavior in longer protein segments is critical for understanding these diseases and obtaining potential therapies. In this study, we combined machine learning and structure-based energy evaluation to examine and predict amyloidogenic segments. Our feature selection method discovered that windows consisting of long amino acid segments of ∼30 residues, instead of the commonly used short hexapeptides, provided the highest accuracy. Weighted contributions of an amino acid at each position in a 27 residue window revealed three cooperative regions of short stretch, resemble the β-strand-turn-β-strand motif in A-βpeptide amyloid and β-solenoid structure of HET-s(218–289) prion (C). Using an in-house energy evaluation algorithm, the interaction energy between two short stretches in long segment is computed and incorporated as an additional feature. The algorithm successfully predicted and classified amyloid segments with an overall accuracy of 75%. Our study revealed that genome-wide amyloid segments are not only dependent on short high propensity stretches, but also on nearby residues

Random amplified polymorphic DNA (RAPD) and enterobacterial repetitive intergenic consensus (ERIC) PCR of Vibrio cholerae from a foodborne outbreak in Limbang, Sarawak

Toxigenic and non-toxigenic V. cholerae strains can be monitored for changes in clones or serogroups, linkages between clinical and environmental isolates, genesis and clonal selection of epidemic strains, and population structure. Also, determining genetic relatedness among V. cholerae strains is critical for determining population genetic structure and evolutionary trends. In collaboration with the Sarawak Government Hospital, the present work was carried out on a total of 16 V. cholerae isolates in order to determine the genetic relatedness or heterogeneity of V. cholerae isolates from a foodborne outbreak among guests who attended a wedding ceremony in Limbang, Sarawak, Malaysia. The random amplified polymorphic DNA (RAPD) and enterobacterial repetitive intergenic consensus (ERIC) were conducted to compare and determine strains and trace diseasecausing microorganism. The RAPD fingerprinting was conducted using a total of 10-mer oligos 100 nmole random primers (OPAE1 - OPAE20). The primers OPAE7, OPAE10, OPAE14, and OPAE17 were selected because they were the most stable and discriminatory for V. cholerae. The PCR fingerprinting of ERIC-PCR was carried out using primer set of ERIC, ERIC1R (5’- ATGTAAGCTCCTGGGGATTCAC-3’), and ERIC2F (5’- AAGTAAGTGACTGGGGTGAGCG-3’). As a result, the 1 confirmed V. cholerae O1 samples were successfully fingerprinted. Based on the profiling results, the genetic fingerprint of some of the isolates from the clinical and environmental samples had 100% similarity, as indicated by the dendrogram. This indicated that the strains shared the same genetic profile. The smaller the genetic distance, the more homogeneous the strains are. The clinical and environmental strains shared some genetic characteristics. As indicated by the dendrogram, some strains were found to be closely linked to one another, while others were heterogeneous. Therefore, RAPD-PCR and ERIC-PCR produced the highest discrimination index. By combining these typing methods, evaluation of isolates' genetic diversity may be improved. The findings of the present work demonstrated the need for continued surveillance of V. cholera in Sarawak, Malaysia

A Review of Hydroxyapatite-Based Coating Techniques: Sol–Gel and Electrochemical Depositions on Biocompatible Metals

New promising techniques for depositing biocompatible hydroxyapatite-based coatings on biocompatible metal substrates for biomedical applications have continuously been exploited for more than two decades. Currently, various experimental deposition processes have been employed. In this review, the two most frequently used deposition processes will be discussed: a sol–gel dip coating and an electrochemical deposition. This study deliberates the surface morphologies and chemical composition, mechanical performance and biological responses of sol–gel dip coating as well as the electrochemical deposition for two different sample conditions, with and without coating. The review shows that sol–gel dip coatings and electrochemical deposition were able to obtain the uniform and homogeneous coating thickness and high adherent biocompatible coatings even in complex shapes. It has been accepted that both coating techniques improve bone strength and initial osseointegration rate. The main advantages and limitations of those techniques of hydroxyapatite-based coatings are presented. Furthermore, the most significant challenges and critical issues are also highlighted