Nitrogen addition to iron powder by mechanical alloying

Nitrogen was alloyed into iron (a) by mechanical processing in a nitrogen gas environment, and (b) by mechanically alloying with iron-nitride powders to characterize resulting nano-structure and nitrogen distribution. Although the infused nitrogen concentration was significantly greater than the thermodynamic equilibrium solubility of iron, no nitrides formed, even for nitrogen concentrations as high as 4.1 wt.% However, a bctFe phase did form. Lattice expansion calculations indicate that the sum of the interstitial bcc-Fe and bctFe nitrogen concentrations was significantly less than the total measured nitrogen concentration. A considerable portion of the mechanically infused nitrogen was determined to be associated with nanograin boundaries.     

Clinical and historical predictors of dental caries on radiographs

Jet injection can be used to introduce genes into the cells of differentiated tissues of living animals and organ cultures. When a solution of plasmid DNA is jet injected into a selected tissue or organ, cells lying in or near the path of the jet injection are transfected with the DNA and the introduced gene(s) are expressed. Since there is minimal morbidity from each jet injection, multiple injections can be performed at the same or nearby sites. Both mRNA and protein expression from transfected genes can be quantitated using standard methods. In addition, the technique is an efficient means of DNA immunization. Methodology for using jet injection to transfer plasmid DNA into the cells of skin, fat, mammary gland, and muscle are described.     

Recovery of gut-associated lymphoid tissue and upper respiratory tract immunity after parenteral nutrition

OBJECTIVE: The authors characterize the recovery of parenteral nutrition-induced changes in gut-associated lymphoid tissue (GALT) and upper respiratory tract immunity with enteral nutrition and provide further information defining the effects of enteral feeding on mucosal immunity. SUMMARY BACKGROUND DATA: The small intestine plays a prominent role in development and maintenance of mucosal immunity, both intestinal and extraintestinal, primarily through immunoglobulin A (IgA)-mediated mechanisms. Prior research has shown that mice fed total parenteral nutrition (TPN) have reduced GALT T and B cells, the cells responsible for IgA production, as well as impaired upper respiratory tract immunity to viral challenge of previously immunized animals. The recovery of TPN-induced changes in GALT and upper respiratory tract immunity after enteral refeeding is studied. METHODS: Male institute of Cancer Research mice received 5 days of TPN followed by 0 to 4 days of chow. Small intestinal GALT was characterized by flow cytometry. In a second experiment, animals were immunized intranasally with moused-adapted influenza virus. Three weeks later, one group received a 5-day course of TPN followed by enteral refeeding for 5 days. A second group received TPN alone. Both groups were challenged with intranasal virus and killed 40 hours postchallenge to determine viral shedding from the upper respiratory tract. RESULTS: Animals fed TPN only had significantly fewer GALT lymphocytes compared with those chow-fed control subjects. Peyer's patch counts increased after a single day of refeeding, returning to normal levels by 48 hours. Lamina propria counts remained significantly depressed after 24 hours of refeeding, but also returned to normal after 48 hours of refeeding. The T-cell and B-cell populations mimicked total cell patterns. Lamina propria CD4+/CD8+ ratio returned to normal only after 72 hours of refeeding. None of the 9 animals refed enterally for 5 days were positive for viral shedding, compared with 8 of 12 matched TPN-fed animals. CONCLUSIONS: Enteral refeeding after TPN is associated with rapid repletion of GALT cellularity, initially within Peyer's patches and subsequently within the lamina propria. Refeeding corrects the impairment of IgA-mediated upper respiratory tract antiviral immunity occurring with TPN administration. This work further enhances the authors' knowledge of the underlying immunologic differences influenced by routes of nutrition.     

The heroic cancer patient: A critical analysis of the relationship between illusion and mental health.

Examines, in the context of cancer illness, S. E. Taylor and J. D. Brown's (see record 1988-16903-001) claim that mental health is to a degree predicated on illusory beliefs about the self, one's control, and the future. The Heroic Model (HM), a stance toward cancer characterized by belief that positive thoughts and feelings, a fighting spirit, and an optimistic outlook will promote cancer remission, is presented as paradigmatic of Taylor and Brown's thesis. Strong and weak formulations of the HM (the former affirming a direct influence of mental states over physical processes, and the latter affirming indirect effects only) are examined with respect to their potential adaptive value as true or false beliefs, with different consequences for well-being. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gel-entrapment of perfluorocarbons: a fluorine-19 NMR spectroscopic method for monitoring oxygen concentration in cell perfusion systems

Oxygenation is a major determinant of the physiological state of cultured cells. 19F NMR can be used to determine the oxygen concentration available to cells immobilized in a gel matrix by measuring the relaxation rate (1/T1) of perfluorocarbons (PFC) incorporated into the gel matrix. In calcium alginate gel beads without cells the relaxation rate (1/T1) of the trifluoromethyl group of perfluorotripropylamine (FTPA) varies linearly with oxygen concentration, with a slope of 1.26 +/- 0.15 x 10(-3) s-1 microM-1 and an intercept of 0.50 +/- 0.04 s-1. During perfusion with medium equilibrated with 95%/5% O2/CO2, changes in PFC T1s indicate that the average oxygen concentration was reduced from 894 +/- 102 microM in the absence of cells to 476 +/- 65 microM and 475 +/- 50 microM in the presence of 0.7 x 10(8) EMT6/Ro and RIF-1 murine tumor cells per milliliter of gel, respectively. The presence of 0.2 microliters of FTPA/ml of gel had no effect on the energy status of the cells as indicated by 31P NMR spectra. To calculate oxygen gradients within the beads from the average PFC T1 of the sample, a mathematical model was used assuming that oxygen is the limiting nutrient for cell metabolism and that the cellular oxygen consumption rate is independent of oxygen concentration. Data for EMT6/Ro cells were fit using experimentally determined perfusion parameters together with literature values for cell volume and oxygen consumption rate.(ABSTRACT TRUNCATED AT 250 WORDS)     

The prevalence of preferential nasal breathing in adults

The prevalence of preferential nasal breathing was studied in an awake adult population. One hundred and ninety-four people consented to gentle manual compression of the nostrils. They were advised to 'breathe in and out', but no further information regarding breathing was given to avoid influencing the patient. One hundred and eighty patients (92.8%) commenced immediate regular relaxed breathing. Fourteen patients (7.2%) had difficulty with oral breathing which ranged from irregular mouth breathing associated with distress to no spontaneous respiration. The prevalence of preferential nasal breathing was strongly associated with increasing age (chi 2 for trend, P = 0.007). In addition, a weakly significant association was demonstrated between a history of asthma and this phenomenon (P = 0.047). These findings suggest a tendency for the elderly person to revert to the infant pattern of obligate nasal breathing. Physicians should be aware of this possibility in the elderly patient, especially prior to any procedure which may induce nasal obstruction.     

Comparison of magnetic resonance volume flow rates, angiography, and carotid Dopplers. Preliminary results

BACKGROUND AND PURPOSE: We compared the results of conventional angiography, carotid Doppler, and magnetic resonance angiography volume flow rates to determine the clinical utility of volume flow rate assessment of blood flow to the anterior circulation in patients with carotid occlusive disease. METHODS: From 11 symptomatic patients, a total of 22 extracranial carotid arteries were studied with all three techniques. The studies were independently read, and regression analysis was used to compare the measurements. RESULTS: Carotid Doppler measurements of the distal extracranial carotid arteries were proportional to the inverse of the extracranial carotid volume flow rate (r = .53, R2 = 29%, P < .01), volume flow rates were proportional to the inverse of measured percent stenosis on angiography (r = .84, R2 = 71%, P < .01), and Dopplers were proportional to angiography (r = .94, R2 = 90%, P < .01). Symptomatic Doppler systolic velocity was significantly higher (P < .002), symptomatic measured stenosis was significantly higher (P < .002), and symptomatic volume flow rate was significantly lower (P < .01) than their respective asymptomatic-side values. These preliminary observations, however, may well change once a large data set, especially one in which more patients with high-grade carotid stenosis are included, is studied. CONCLUSIONS: Assessment of carotid volume flow rates by magnetic resonance angiography quantifies flow reduction secondary to atherosclerotic occlusive disease. The easily obtained flow data add both documentation of arterial flow characteristics related to internal carotid stenosis and information regarding the adequacy of collateral pathways.