Potential for the use of low-grade limonite ores from dumps

This article presents results of studies performed to determine the feasibility of using low-grade limonite ores from dumps by sintering them with high-grade concentrates. The components of the charge include concentrates from the Sokolovsko-Sarbaiskii deposit and fines screened at the crushing-sorting plant that processes chromium-nickel limonites from the Novokievskoye and Novopetropavlovskoye deposits. Laboratory tests and commercial trials have shown that the sintering operation can be performed with a high degree of efficiency. Unit productivity reaches 1.24 tons/m²/h based on the yield of usable sinter and 0.58 tons/m² per hour based on the iron content of the sinter. The quality of the sinter meets the requirements for blast-furnace smelting. The results as a whole demonstrate the feasibility of utilizing bank limonite ore. __________ Translated from Metallurg, No. 2, pp. 30–31, February, 2006.     

Potential use of poliovirus as a vector

The live attenuated Sabin strains of poliovirus have proven their efficacy at inducing a good humoral and secretory antibody response in humans. The extensive characterization of poliovirus neutralization antigenic sites and the atomic resolution of the three-dimensional structure of the viral capsid have enabled the use of the most stably attenuated poliovirus strain (the Sabin type 1 strain) as a vector for the presentation of short foreign antigenic domains in place of one of its own neutralization antigenic sites. The creation of such chimeras has been achieved by manipulating poliovirus infectious cDNA and transfecting the resulting chimeric cDNAs onto susceptible cell cultures. However, this epitope-presentation system has a limitation in terms of the sequence and size of the foreign domain that can be incorporated into the poliovirus capsid without disrupting virus viability. This has led to the construction of poliovirus hybrid genomes bearing insertions of longer heterologous sequences in place of part of the poliovirus structural genes. Upon transfection onto susceptible cells providing the poliovirus structural proteins in trans (e.g. cells previously infected with the Sabin 1 strain), stocks of encapsidated RNA replicons which expressed the foreign protein could be obtained. In addition, viable recombinant viruses bearing insertions of heterologous sequences at various places into the poliovirus genome without deleting poliovirus sequences have been reported. Potential applications of these chimeric and recombinant polioviruses in the engineering of new recombinant vaccines are discussed.     

Development of a model for evaluation of microbial cross-contamination in the kitchen

Foods can become contaminated with pathogenic microorganisms from hands, the cutting board, and knives during preparation in the kitchen. A laboratory model was developed to determine occurrence of cross-contamination and efficacy of decontamination procedures in kitchen food-handling practices. Enterobacter aerogenes B199A, an indicator bacterium with attachment characteristics similar to that of Salmonella spp., was used. Chicken meat with skin inoculated with 10(6) CFU of E. aerogenes B199A/g was cut into small pieces on a sterile cutting board. The extent of cross-contamination occurring from meat to the cutting board and from the cutting board to vegetables (lettuce and cucumbers) subsequently cut on the board was determined. Swab samples from the cutting board, hand washings, and lettuce and cucumber samples revealed that approximately 10(5) CFU of E. aerogenes/cm2 were transferred to the board and hands and approximately 10(3) to 10(4) CFU of E. aerogenes/g to the lettuce and cucumbers. The surfaces of the cutting board and hands were treated with antibacterial agents after cutting the meat, and counts of E. aerogenes on the cutting board and vegetables (lettuce and cucumbers) were determined. Results revealed that use of the disinfectant reduced the population of E. aerogenes to almost nondetectable levels on the cutting boards. The average counts after treatment were < 20 CFU/g of vegetable and ranged from < 20 to 200 CFU per cm2 or g on the cutting board and subsequently on the vegetables. These results indicate that bacteria with attachment characteristics similar to Salmonella spp. can be readily transferred to cutting boards during food preparation and then cross-contaminate fresh vegetables if the boards are not cleaned. Application of a kitchen disinfectant can greatly reduce bacterial contamination on cutting boards.     

Investigation of the performance of an expandable polystyrene injector for use in the lost-foam casting process

A significant portion of casting defects in the lost-foam casting (LFC) process can be traced back to a lack of consistency in the expandable polystyrene (EPS) foam pattern. The present study focuses on determining the cause of EPS foam-pattern irregularities through the investigation of the two-phase flow of an EPS bead injector. The process variables studied during this experiment include fill time, fill pressure, EPS bead canister pressure, and fill-hose diameter. It was found that the air flow rate under a vented EPS-bead-canister condition using a 1.90-cm (3/4-in.)-diameter fill hose increases 51 pct from a 276 kPa (40 psig) fill pressure to a 552 kPa (80 psig) fill pressure, and the EPS bead-mass per cycle for a 3-second fill time increased 28 pct, from a 276 kPa fill pressure to a 552 kPa fill pressure. It was also discovered that the air flow rate under a pressurized EPS-bead-canister condition is not a strong function of fill pressure, but instead strongly depends on the EPS bead canister pressure. The average EPS bead-mass per cycle for a pressurized canister and a 1.90-cm-diameter fill hose increased 45 pct from 55.22 g for a 28 kPa EPS bead canister pressure to 80.21 g for an 83 kPa EPS bead canister pressure at a fill pressure of 276 kPa. The EPS bead-mass per cycle for a 1.27-cm-diameter fill hose exhibited a lower EPS bead-mass per cycle than that for a 1.90-cm-diameter fill hose for both the vented- and pressurized-canister conditions; however, the air flow rates and tip pressures observed for a 1.27-cm (1/2-in.)-diameter fill hose showed similar behavior to those for a 1.90-cm-diameter fill hose. Four correlations are proposed to predict the dimensionless bead-mass per cycle from either the dimensionless fill or canister pressure and the dimensionless fill time.     

Evaluation of the acceptability of a needleless vascular-access system by nurses

BACKGROUND: Needleless intravenous-access devices have been introduced in an effort to reduce needlestick injuries and possible transmission of blood-borne pathogens to health care workers. However, there are no data on the acceptance of these devices by nursing personnel. METHODS: A survey of nursing personnel was taken at Indiana University Medical Center after introduction of a needleless intravenous device to determine their opinion after use of the needleless device. RESULTS: The majority of the nurses (72 of 94, 70%) had a favorable overall opinion of the device. Among those with a favorable opinion, 76% (55/72) responded that reduced risk of needlestick injury was the most important reason. Among those who had a negative opinion about the needleless-device system, 32% (7/22) reported that contamination risk was their major concern. Those who were trained before device use were more likely to properly use and maintain the needleless intravenous-access system. Of 89 respondents, 75.3% (67/89) believed that the initial training was adequate; however, 43% (29/67) thought that additional training after using the device for some time would have been beneficial. CONCLUSIONS: Comprehensive education programs that include training before and after device use are necessary if new needleless intravenous-access systems are to be successfully introduced and accepted by nursing personnel.     

Identification of yeast proteins from two-dimensional gels: working out spot cross-contamination

With the complete sequence of the yeast genome now available, efforts by many laboratories are underway to identify each of the spots on two-dimensional (2-D) gels corresponding to the most abundant yeast proteins. The high mass accuracy now attainable using matrix assisted laser desorption/ionization (MALDI)-mass spectrometry equipped with delayed extraction simplifies the process of identification, such that many spots can be unambiguously identified in a short period of time merely by using peptide mass fingerprinting and generally available database matching programs. Although it is not always possible to match spots between gels run by different laboratories, proteins generally yield the same abundant proteolytic fragments when tryptic digestions are performed. Databases containing these signature peptides not only simplify the task of reidentifying proteins from different gels, but also make it possible to identify small amounts of cross-contaminating proteins from different spots, as well as common extraneous contaminants such as human keratins. In this paper, we present data on the identification of > 20 previously unreported yeast proteins from 2-D gels. Some novel proteins were identified from randomly analyzed spots. Focusing on 14 spots in a narrow-pH-range gel, we demonstrate how organizing peak-table data and peptide match-list data into databases enables the identification of a larger percentage of the peaks.     

Bloodstream infection associated with needleless device use and the importance of infection-control practices in the home health care setting

The influence of infection-control practices on bloodstream infection (BSI) risk was examined in a home health care setting in which three needleless devices were used consecutively. A case-control study and a retrospective cohort study were conducted. Risk factors for BSI included lower education level, younger age, having a central venous catheter (CVC) with multiple ports, or having a tunneled CVC. Among patients with a tunneled CVC, those at greatest risk had been allowed to shower rather than bathe and to get their exit site wet (P<.01). A high proportion (49%) of isolates were hydrophilic gram-negative bacteria, suggesting water sources of infection. In the cohort study, the BSI rate decreased as the frequency of changing the needleless device end cap increased from once weekly up to every 2 days, suggesting that the mechanism for BSI may involve contamination from the end cap. These findings may help to develop infection-control measures specific to home health care.     

Potential use of cytokine therapy in poultry

The time course of incorporation of [14C]arachidonic acid and [3H]docosahexaenoic acid into various lipid fractions in placental choriocarcinoma (BeWo) cells was investigated. BeWo cells were found to rapidly incorporate exogenous [14C]arachidonic acid and [3H] docosahexaenoic acid into the total cellular lipid pool. The extent of docosahexaenoic acid esterification was more rapid than for arachidonic acid, although this difference abated with time to leave only a small percentage of the fatty acids in their unesterified form. Furthermore, uptake was found to be saturable. In the cellular lipids these fatty acids were mainly esterified into the phospholipid (PL) and the triacyglycerol (TAG) fractions. Smaller amounts were also detected in the diacylglycerol and cholesterol ester fractions. Almost 60% of the total amount of [3H]Docosahexaenoic acid taken up by the cells was esterified into TAG whereas 37% was in PL fractions. For arachidonic acid the reverse was true, 60% of the total uptake was incorporated into PL fractions whereas less than 35% was in TAG. Marked differences were also found in the distribution of the fatty acids into individual phospholipid classes. The higher incorporation of docosahexaenoic acid and arachidonic acid was found in PC and PE, respectively. The greater cellular uptake of docosahexaenoic acid and its preferential incorporation in TAG suggests that both uptake and transport modes of this fatty acid by the placenta to fetus is different from that of arachidonic acid.     

Spot turbulence,breakup, and coalescence of bubbles released from a porous plug injector into a gas-stirred ladle

Many metallurgical processes are connected with gas injection into liquid metals for refining purposes. For this reason, considerable effort has been made during the past 2 decades to investigate gas-injection operations in steelmaking ladles. Numerous physical and mathematical models are available in the literature as well as experiments (most of them performed in the air-water model). In theoretical works, usually, the bubble size is assumed constant, but this approximation is good just at low gas flow rates. When the gas flow rate increases, three different types of bubble dispersion patterns are observed in experiments. This situation cannot be predicted by means of the turbulence multiphase models normally implemented in commercial CFD codes. Their results predict a smooth (and wrong) bubble-size increase and not a sudden transition from a pattern to another, as in experiments. In this articles a new idea for approaching the bubble turbulence in the ladle, called “spot turbulence,” is presented and comparison with experimental data shown.     

Using a biological indicator to detect potential sources of cross-contamination in the dental operatory

The authors conducted a study using surveillance monitoring methodology to identify operatory contamination and to evaluate the effectiveness of infection control procedures. Viridans streptococci were evaluated as biological indicators of oral contamination. Viridans streptococci, abundant in human saliva, were detected on operatory surfaces after dental treatments were finished and surfaces were disinfected. The findings validate current concepts of infection control as demonstrated in barrier methods.     

Bacterial cross-contamination of meat during liquid nitrogen immersion freezing

Prerigor beef carcass surface tissue (BCT) was used to simulate lamb carcasses on a processing line with a 15-min liquid nitrogen (LN) immersion freezing step, and the potential for the dissemination of bacteria during freezing was examined. Streptomycin-resistant strains of Listeria innocua and Escherichia coli O157:H7 spiked into a fecal slurry were inoculated onto BCT pieces that were introduced into the freezing process to represent contaminated carcasses. Following this introduction, subsequently frozen uninoculated BCT, LN, and LN containers were examined for the inoculated organisms. In the first study, BCT samples were inoculated with ca. 7 log CFU/cm2 of both L. innocua and E. coli O157:H7, spray washed with water and frozen, distributed among uninoculated BCT, in LN for 15 min. In two separate trials, L. innocua was recovered by enrichment from all uninoculated BCT and LN samples. E. coli O157:H7 was also recovered from uninoculated BCT and LN, but this cross-contamination was more sporadic. Both species were recovered from the LN container following freezing. Attempts to enumerate cross-contaminating bacteria in the second trial indicated that contaminating levels were low (< 1.0 CFU/cm2 BCT). In a second study, a 2.0% lactic acid spray wash was used to reduce further the numbers of L. innocua introduced into the freezing system and resulted in fewer positive samples, although this organism was still recovered from many uninoculated BCT samples. When either bacterium was inoculated at lower initial levels (1.35 to 1.77 log CFU/cm2) and BCT was water or 2.0% lactic acid spray washed prior to freezing, neither L. innocua nor E. coli O157:H7 was recoverable by enrichment from uninoculated BCT, LN, or from the freezing container. Results demonstrate that bacterial cross-contamination of meat during LN immersion freezing can occur but indicate that the use of good sanitation practices and product with low microbial numbers can limit this occurrence.     

Potential use of BacT/Alert automated blood culture system for antifungal susceptibility testing

A simple, rapid susceptibility test is needed to determine the possible resistance of yeasts to commonly used antifungal agents. The BacT/Alert automated blood culture system was evaluated as one technology for development of such a test. Yeast nitrogen base was used as the growth medium, and amphotericin B was the test antifungal agent. Isolates of various Candida species, Torulopsis glabrata, Saccharomyces cerevisiae, and Cryptococcus neoformans were evaluated. The results suggest that detection of amphotericin B resistance of yeast isolates within 12 to 14 h after inoculation of test medium is possible.     

A light localizer for use at large distances from a radiation source

In the superconducting cyclotron used for neutron therapy at Harper Hospital, space limitations prevented the use of a simple conventional light localizing system, employing a single mirror and a light source. The superconducting magnet coil is close to the neutron producing target and the vacuum window separating the acceleration chamber from atmospheric pressure is situated approximately 56 cm from this target. Therefore, the light localizing system must be designed to incorporate lenses, mirrors, an optical fiber light pipe and adjustment motors, in order to make the system compact enough to fit in the available space and to allow easy access for adjustment and alignment. The design of the light localizing system is explained in detail.