Controlling bacterial contamination of an enteral formula through the use of a unique closed system: contamination, enteral formulas, closed system

Contamination of enteral diets may play an essential role in formula tolerance and safety for patients. Contaminated enteral formula commonly support microbiological growth. Commercially sterile liquid formulas received from the manufacturer are required by the Food & Drug Administration (FDA) to be shelf-stable and free from enteric pathogens. This study examined the use of large volume, closed system containers in a typical nursing home. Large volume (1500 mL) containers with unique pierceable caps and piercing spikes were studied to determine their ability to reduce the incidence of microbiological contamination due to their design and ability to decrease handling requirements. This study took place in a room of a typical nursing home. In this clinical setting, 211 containers and administration spike sets were evaluated following a 36-h hangtime. Contamination was virtually nondetectable. Nursing staff in a clinical facility can effectively utilize a large volume, prefilled, ready-to-use feeding system to achieve delivery of noncontaminated product for up to 36 h hangtime.     

Properties of phyllosilicate-based porous ceramics shaped by conventional tape casting and freeze tape casting

Silicate ceramics were shaped using tape casting (TC) and freeze tape casting (FTC) processes from three clays labeled HCR, KORS, and KCR. These clays exhibited mass content of 77% halloysite–10 Å, 29% kaolinite, and 98% kaolinite minerals, respectively. After casting the slurries, the dried tapes were sintered at 1200°C. The microstructure changes were characterized before and after sintering using scanning electron microscopy. The apparent porosity of TC samples was lower (36–47 vol.%) compared to values obtained with FTC samples (67–79 vol.%). The latter samples exhibited a highly textured porosity, with micron-sized pores aligned perpendicular to the tape surfaces. Upon sintering, the porosity of TC samples tended to decrease conversely to the case of FTC samples. Such behavior seemed related to the simultaneous effect of organic additives and ice templating. Consequently, the FTC samples showed a relatively low mechanical strength of 3–7 MPa and thermal conductivity of .14– .22 W m⁻¹ K⁻¹. After sintering, the mullite crystallization contributed to strengthen the bulk materials, helping to compensate for the detrimental effect of porosity on the stress to rupture and on thermal conductivity values.     

Synthesis of low molecular weight polyethylenes and polyethylene mimics with controlled chain structures

The controlled synthesis of narrowly distributed low molecular weight polymers with functionalization possibilities is of great industrial interests. Although living polymerization allows for control over polymer architecture, the production of low molecular weight polymers with low polydispersities via living polymerization systems is challenged by the use of large amounts of catalysts and broadening in molecular weight distribution. This review addresses the synthesis of narrowly distributed, functional, low molecular weight polyethylene and polyethylene mimics. The review is structured for quick identification of relevant systems for the production of specific polymer architectures with specific cost, efficiency, and safety concerns.     

Low-cost testing of high-density logic components

The evolution of a testing method and architecture of a logic-device tester to be used for the next generation of IBM's high-density CMOS ASIC (application-specific integrated circuit) logic components is described. The tester's design is based on the architecture of an existing IBM memory tester rather than on a conventional logic-tester design. The testing strategy calls for boundary-scan in each component design, built-in self-test logic within embedded memory arrays, and the use of weighted random-pattern logic testing. The development of the tester hardware is discussed, and capital costs of the new tester are compared with those of other approaches     

Synthesis and characterization of poly([3,4,c]furano-1-germa-1,1-dimethylcyclopentane)

Summary Poly([3,4,c]furano-1-germa-1,1-dimethylcyclopentane) (I) has been prepared by the anionic ring opening polymerization of 3-oxa-7,7-dimethyl-7-germabicyclo[3.3.0]- octa-1,4-diene (II) co-catalyzed byn-butyllithium and HMPA in THF. I has been characterized by¹H,¹³C NMR, IR and UV spectroscopy as well as by elemental analysis. The molecular weight distribution of I has been determined by gel permeation chromatography (GPC), its thermal stability established by thermogravimetric analysis (TGA) and its glass transition temperature (T_g) measured by differential scanning calorimetry (DSC).     

Impact of agglomeration on the relaxometric properties of paramagnetic ultra-small gadolinium oxide nanoparticles

Ultra-small gadolinium oxide nanoparticles (US-Gd(2)O(3)) are used to provide 'positive' contrast effects in magnetic resonance imaging (MRI), and are being considered for molecular and cellular imaging applications. However, these nanoparticles can aggregate over time in aqueous medium, as well as when internalized into cells. This study is aimed at measuring in vitro, in aqueous medium, the impact of aggregation on the relaxometric properties of paramagnetic US-Gd(2)O(3) particles. First, the nanoparticle core size as well as aggregation behaviour was assessed by HRTEM. DLS (hydrodynamic diameter) was used to measure the hydrodynamic diameter of nanoparticles and nanoaggregates. The relaxometric properties were measured by NMRD profiling, as well as with (1)H NMR relaxometers. Then, the positive contrast enhancement effect was assessed by using magnetic resonance scanners (at 1.5 and 7 T). At every magnetic field, the longitudinal relaxivity (r(1)) decreased upon agglomeration, while remaining high enough to provide positive contrast. On the other hand, the transverse relaxivity (r(2)) slightly decreased at 0.47 and 1.41 T, but it was enhanced at higher fields (7 and 11.7 T) upon agglomeration. All NMRD profiles revealed a characteristic relaxivity peak in the range 60-100 MHz, suggesting the possibility to use US-Gd(2)O(3) as an efficient 'positive-T(1)' contrast agent at clinical magnetic fields (1-3 T), in spite of aggregation.     

Direct evidence for dissociated megakaryocytic chimaerism in a Wiskott-Aldrich patient successfully allografted

We report a Wiskott-Aldrich patient who underwent allogeneic bone marrow transplantation from his HLA-identical sister at the age of 25. Conditioning regimen consisted of cyclophosphamide (180 mg/kg) and thoraco-abdominal irradiation (6 Grays). Cytogenetic follow-up revealed rapid and complete lymphoid chimaerism, but prolonged mixed bone marrow chimaerism. Correlative interphase cytogenetics performed on bone marrow smears using dual-colour fluorescence in situ hybridization with X and Y specific probes showed that the proportion of donor cells was significantly higher within megakaryocytes than in other lineages. This patient therefore presented with dissociated lineage engraftment, which is not exceptional in congenital diseases and aplastic anaemia, but has not previously been described in Wiskott-Aldrich syndrome. Bone marrow transplantation was successful despite this delayed engraftment which ensured adequate production in the involved cell lines.     

Application of parallel forward-error correction in two-dimensional optical-data links

We propose the use of on-chip parallel forward-error correction (FEC) to improve the performance of two-dimensional (2-D) optical-data links (2-D-ODLs). Using an optical system model that describes a 2-D-ODL, we show the merits of using the Golay code as an FEC scheme to enable the reliable operation of 2-D-ODLs in the presence of erasures [e.g., a dead laser or photodetector, a dark fiber, an alignment problem, or a fault on the application-specific integrated circuit (ASIC)]. In addition, we study the impact of using on-chip FEC in 2-D-ODLs and show that FEC can reduce the launched optical power requirements, reduce on-chip power consumption, and relax the throughput requirements of the optical system.     

Dependence of ductile fracture toughness of a weld metal on notch root radius and inclusion content

Using different fluxes of high and low basicity, two different welds have been produced with low and high inclusion content. Inclusions have been characterized in 2 and 3 dimensions, from measurements on both polished sections and on fracture surfaces. The fracture toughness is evaluated with J0integral, crack tip opening displacement (CTOD) and stretch zone width measurements. Ductile fracture satisfies the criterion of a critical fracture strain over a characteristic distance. These two critical values can be determined from the results obtained with blunt notch specimens. Characteristic distances are an order of magnitude larger than the inclusion spacing. This is attributed to the need to reach conditions of sustained crack growth for initiation of ductile tearing.

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Résumé A l'aide de flux différents de forte et faible basicité, on a produit deux soudures à faible et forte teneur inclusionnaire. Les inclusions sont caractérisées en 2 et 3 dimensions par des mesures sur coupes polies et sur les surfaces de rupture. La ténacité à la rupture est évaluée par l'intégrale J, l'ouverture critique en fond de fissure (CTOD) et la mesure de la zone d'étirement. La rupture ductile satisfait la condition qu'une déformation critique de rupture soit atteinte sur une distance caractéristique. Ces deux valeurs critiques peuvent être déterminées à partir des résultats obtenus sur éprouvettes avec rayon d'entaille. Les distances caractéristiques sont un ordre de grandeur plus grandes que les distances inter-inclusionnaires. On attribue cette différence à la nécessité de satisfaire les conditions de croissance soutenue de la fissure pour l'initiation de la rupture ductile.

     

Evaluation of the fracture toughness of hot-rolled low-alloy Ti-V plate steel

The effects of varying finish rolling temperature (FRT) and cooling rate on the mechanical properties of hot rolled plates of an experimental low-alloy Ti-V steel were studied. Fracture toughness was evaluated for various types of specimens at slow and high deformation rates. However, the transition temperatures determined by the various tests do not always correlate. Therefore, it is recommended that fracture toughness be evaluated by both static and dynamic testing. Following a low cooling rate, the best plate properties are obtained at the lowest FRT in the austenite-ferrite range, although occurrence of delaminations at this temperature may be detrimental for specific applications. Higher cooling rates produce higher strength but lower toughness than lower cooling rates in plates with the same FRT.