Biodegradable nanomats produced by electrospinning: expanding multifunctionality and potential for tissue engineering

With increasing interest in nanotechnology, development of nanofibers (n-fibers) by using the technique of electrospinning is gaining new momentum. Among important potential applications of n-fiber-based structures, scaffolds for tissue-engineering represent an advancing front. Nanoscaffolds (n-scaffolds) are closer to natural extracellular matrix (ECM) and its nanoscale fibrous structure. Although the technique of electrospinning is relatively old, various improvements have been made in the last decades to explore the spinning of submicron fibers from biodegradable polymers and to develop also multifunctional drug-releasing and bioactive scaffolds. Various factors can affect the properties of resulting nanostructures that can be classified into three main categories, namely: (1) Substrate related, (2) Apparatus related, and (3) Environment related factors. Developed n-scaffolds were tested for their cytocompatibility using different cell models and were seeded with cells for to develop tissue engineering constructs. Most importantly, studies have looked at the potential of using n-scaffolds for the development of blood vessels. There is a large area ahead for further applications and development of the field. For instance, multifunctional scaffolds that can be used as controlled delivery system do have a potential and have yet to be investigated for engineering of various tissues. So far, in vivo data on n-scaffolds are scarce, but in future reports are expected to emerge. With the convergence of the fields of nanotechnology, drug release and tissue engineering, new solutions could be found for the current limitations of tissue engineering scaffolds, which may enhance their functionality upon in vivo implantation. In this paper electrospinning process, factors affecting it, used polymers, developed n-scaffolds and their characterization are reviewed with focus on application in tissue engineering.     

Bambusuril Anion Receptors

Bambusurils are macrocyclic compounds whose synthesis was first reported in 2010. Since then bambusurils have been investigated mainly because of its six-membered homologues’ outstanding binding affinities towards inorganic anions in both organic solvents and water. Here we summarize the most important aspects of bambusuril chemistry. Basic characteristics of bambusurils are presented, followed by details of their synthesis, and a discussion of their supramolecular properties, with an emphasis on binding in water. Potential applications of bambusurils are highlighted at the end of the review.     

Biodegradable nanomats produced by electrospinning: expanding multifunctionality and potential for tissue engineering

With increasing interest in nanotechnology, development of nanofibers (n-fibers) by using the technique of electrospinning is gaining new momentum. Among important potential applications of n-fiber-based structures, scaffolds for tissue-engineering represent an advancing front. Nanoscaffolds (n-scaffolds) are closer to natural extracellular matrix (ECM) and its nanoscale fibrous structure. Although the technique of electrospinning is relatively old, various improvements have been made in the last decades to explore the spinning of submicron fibers from biodegradable polymers and to develop also multifunctional drug-releasing and bioactive scaffolds. Various factors can affect the properties of resulting nanostructures that can be classified into three main categories, namely: (1) Substrate related, (2) Apparatus related, and (3) Environment related factors. Developed n-scaffolds were tested for their cytocompatibility using different cell models and were seeded with cells for to develop tissue engineering constructs. Most importantly, studies have looked at the potential of using n-scaffolds for the development of blood vessels. There is a large area ahead for further applications and development of the field. For instance, multifunctional scaffolds that can be used as controlled delivery system do have a potential and have yet to be investigated for engineering of various tissues. So far, in vivo data on n-scaffolds are scarce, but in future reports are expected to emerge. With the convergence of the fields of nanotechnology, drug release and tissue engineering, new solutions could be found for the current limitations of tissue engineering scaffolds, which may enhance their functionality upon in vivo implantation. In this paper electrospinning process, factors affecting it, used polymers, developed n-scaffolds and their characterization are reviewed with focus on application in tissue engineering.     

Validation of pepperoni process for control of Shiga toxin-producing Escherichia coli

The objective of this study was to compare the survival of non-O157 Shiga toxin-producing Escherichia coli (STEC) with E. coli O157:H7 during pepperoni production. Pepperoni batter was inoculated with 7 log CFU/g of a seven-strain STEC mixture, including strains of serotypes O26, O45, O103, O111, O121, O145, and O157. Sausages were fermented to pH ≤4.8, heated at 53.3°C for 1 h, and dried for up to 20 days. STEC strains were enumerated at designated intervals on sorbitol MacConkey (SMAC) and Rainbow (RA) agars; enrichments were completed in modified EC (mEC) broth and nonselective tryptic soy broth (TSB). When plated on SMAC, total E. coli populations decreased 2.6 to 3.5 log after the 1-h heating step at 53.3°C, and a 4.9- to 5-log reduction was observed after 7 days of drying. RA was more sensitive in recovering survivors; log reductions on it were 1.9 to 2.6, 3.8 to 4.2, and 4.6 to 5.3 at the end of cook, and at day 7 and day 14 of drying, respectively. When numbers were less than the limit of detection by direct plating on days 14 and 20 of drying (representing a 5-log kill), no more than one of three samples in each experiment was positive by enrichment with mEC broth; however, STEC strains were recovered in TSB enrichment. Freezing the 7-day dried sausage for 2 to 3 weeks generated an additional 1- to 1.5-log kill. Confirmation by PCR revealed that O103 and O157 had the greatest survival during pepperoni productions, but all serotypes except O111 and O121 were occasionally recovered during drying. This study suggests that non-O157 STEC s trains have comparable or less ability than E. coli O157 to survive the processing steps involved in the manufacture of pepperoni. Processes suitable for control of E. coli O157 will similarly inactivate the other STEC strains tested in this study.     

SedAlp – Sedimentmanagement in alpinen Einzugsgebieten

The primary goal of SedAlp is to contribute to the integrated management of sediment transport in Alpine basins, which involves effectively reducing sediment-related risks, promoting the enhancement of riverine ecosystems and reducing the impacts of hydropower plants, while balancing the implementation of EU Directives and national laws (e.g. RES, WFD, NGP etc.). The project includes 34 pilot measures undertaken in various representative Alpine river basins of all countries involved and contributes in particular to the use of sediment and wood transfer monitoring in a large set of Alpine catchments, an approach that can help us to better understand the spatial and temporal variability of processes and to provide planning, predictive and warning tools, as well as sediment and wood management recommendations to minimize risks. The project covers the development of both strategic policy and implementation actions to improve sediment continuity in Alpine river basins. In doing so, SedAlp takes into account the geological and climatic variability across the Alps, which can produce complex patterns of sediment transfer, while also identifying those management conflicts shared by different regions.     

Barium enema, proctosigmoidoscopy and upper gastrointestinal series in the preoperative evaluation of the cancer patient

Charts of 566 patients admitted to the Surgery Branch, National Cancer Institute over a five year period were reviewed. Routine upper gastrointestinal series was performed in 453 patients; barium enemas in 490; and proctosigmoidoscopies in 342. Upper gastrointestinal series detected no metastases or second primary malignancies but delineated the extent of large intra-abdominal tumors. Barium enema and proctosigmoidoscopy together revealed three unsuspected primary colonic tumors (1.2% in patients over 50 years of age). Sigmoidoscopy and examination of the stool for occult blood would have detected the same patients. Barium enema may be limited to surgical cancer patients in whom the extent of local tumor invasion is to be defined and to older patients in whom colonic tumors are suspected. Neither UGIS nor barium enema appear to be of value as a routine preoperative screening test in surgical cancer patients.     

Flume Test Section Length and Sediment Erodibility

This paper analyzes the effect of flume test section length on sediment erodibility measurements. A modular flume was constructed and experiments were conducted with two test section lengths: 0.15 and 1.10?m. The internal height and width of the flume were 0.11 and 0.13?m, respectively. A fine (7?μm) commercially available quartz sediment was used for the tests. The expectation was that the shorter flume test section would experience a significantly higher erosion rate (per unit surface area) due to its greater sensitivity to edge effects (i.e., scour) at the entrance and exit of the flume test section. However, the measured erosion rates at comparable bottom stresses were only 35% greater in the short test-section tests. These results were consistent with the lack of significant scour development at the entrance or exits of the test sections. Hence, flume test section length alone does not appear to significantly affect erodibility measurements provided edge effects (i.e., scour) are minor.     

Poly(imide-amide)-poly(ethylene glycol) hybrid networks: nanostructure,molecular dynamics and membrane properties

Summary Nanometer-scale structure, molecular dynamics (at 100-580 K) and membrane properties were studied in two series of poly(imide-amide) (PIA)-poly(ethylene glycol) (PEG) hybrid networks with regularly varied composition and different lengths of PEG crosslinks (M_n= 1000 or 3400). Combined WAXD/SAXS/polarized microscopy/DSC/DRS/TSDC/creep rate spectroscopy (CRS) analysis of these hybrids was performed. Depending on their composition, semicrystalline or mesomorphous, or amorphous state, and nanostructural heterogeneity were observed for these networks. They could be subdivided into (a) the PIA-rich hybrids with spatially isolated PEG domains, “suppressed” dynamics in the PEG glass transition, and PIA domains with T_g=520–570 K (group 1), and (b) the other hybrids with a continuous PEG phase and low-temperature glass transition only (group 2). Heterogeneity in segmental dynamics was revealed by CRS over the temperature range from T_g^PEG to T_g^PIA. In the second group of hybrids, the permeability coefficients were higher, by two or three orders of magnitude, for organic vapors than those for air gases.