Calcium Oxalate Crystallization from Inhibited Solutions

The induction periods of calcium oxalate precipitation at high supersaturations were measured and the degrees of inhibition in the presence of different trace quantities of polyphosphates were determined. Crystals were grown from uninhibited and from partially inhibited solutions. The presence of both polyphosphates and of cationic impurities affects the crystal habit very strongly: rod-like crystals up to 3 mm in length grew from inhibited solutions in a week, whereas very small round particles of 10^?2 mm size sprang from the uninhibited solutions. Some previously published mechanisms are reviewed, and a new, comprehensive, heterogeneous nucleation mechanism of growth is proposed to explain the simultaneous inhibition of precipitation and inducement to growth of large crystals.     

The role of spatial abilities and age in performance in an auditory computer navigation task

Age-related differences in spatial ability have been suggested as a mediator of age-related differences in computer-based task performance. However, the vast majority of tasks studied have primarily used a visual display (e.g., graphical user interfaces). In the current study, the relationship between spatial ability and performance in a non-visual computer-based navigation task was examined in a sample of 196 participants ranging in age from 18 to 91. Participants called into a simulated interactive voice response system and carried out a variety of transactions. They also completed measures of attention, working memory, and spatial abilities. The results showed that age-related differences in spatial ability predicted a significant amount of variance in performance in the non-visual computer task, even after controlling for other abilities. Understanding the abilities that influence performance with technology may provide insight into the source of age-related performance differences in the successful use of technology.     

Study of the solid-matrix phosphorescence properties of a heterocyclic aromatic amine and the heat capacities of glucose glasses as the temperature decreases

The heat capacities were obtained from 294 to 133 K for four glucose-glass systems. Two of the glasses were prepared from crystalline glucose. One of the glasses contained the heavy-atom salt NaI and the other glass did not contain NaI. The other two glasses were similar, but they were prepared from glucose melts. Correlations were developed between the solid-matrix phosphorescence (SMP) lifetimes and intensities of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in the glucose glasses and the heat capacities of the glucose sugar glasses as the temperature was lowered. Several plots of reciprocal SMP lifetime versus reciprocal temperature and reciprocal SMP lifetime versus reciprocal heat capacity were compared. Also, the reciprocal SMP intensity versus reciprocal temperature plots were compared with the corresponding reciprocal SMP intensity versus reciprocal heat capacity plots. In addition, basic photo-physical equations were used to develop relationships among the lifetime data, the intensity data, and the heat capacity data. The heat capacity data and SMP lifetime data, obtained as the temperature was lowered, were discussed in relationship to low-frequency vibrational modes and beta-relaxation phenomena in the glucose glasses. The discussion of these phenomena offered explanations for some of the loss of the excited triplet-state energy of PhIP in the glucose sugar glasses.     

MALDI-FTICR imaging mass spectrometry of drugs and metabolites in tissue

A new approach is described for imaging mass spectrometry analysis of drugs and metabolites in tissue using matrix-assisted laser desorption ionization-Fourier transform ion cyclotron resonance (MALDI-FTICR). The technique utilizes the high resolving power to produce images from thousands of ions measured during a single mass spectrometry (MS)-mode experiment. Accurate mass measurement provides molecular specificity for the ion images on the basis of elemental composition. Final structural confirmation of the targeted compound is made from accurate mass fragment ions generated in an external quadrupole-collision cell. The ability to image many small molecules in a single measurement with high specificity is a significant improvement over existing MS/MS based technologies. Example images are shown for olanzapine in kidney and liver and imatinib in glioma.     

Advanced radiation measurement techniques in diagnostic radiology and molecular imaging

This paper reports some technological advances recently achieved in the fields of micro-CT and small animal PET instrumentation. It highlights a balance between image-quality improvement and dose reduction. Most of the recent accomplishments in these fields are due to the use of novel imaging sensors such as CMOS-based X-ray detectors and silicon photomultipliers (SiPM). Some of the research projects carried out at the University of Pisa for the development of such advanced radiation imaging technology are also described.     

Mixture design applied to optimize a directly compressible powder produced via cospray drying

Coprocessing via spray drying was applied to improve the compactability of acetaminophen and to select an optimal formulation. Four-component mixtures containing acetaminophen, mannitol, erythritol, and maltodextrin were produced by cospray drying. A D-optimal mixture design was constructed to evaluate the spray dried powder and tablet properties. An increasing mannitol and erythritol content improved powder flowability and density. However, a higher erythritol concentration in the spray dried powder mixture had a negative influence on tablet tensile strength and friability. A higher maltodextrin content increased tablet tensile strength and improved tablet friability, while disintegration time, average particle size, powder flowability, density, and hygroscopicity were negatively influenced.     

"Work-family conflict: Experiences and health implications among immigrant Latinos": Correction.

Reports an error in "Work-family conflict: Experiences and health implications among immigrant Latinos" by Joseph G. Grzywacz, Thomas A. Arcury, Antonio Márin, Lourdes Carrillo, Bless Burke, Michael L. Coates and Sara A. Quandt (Journal of Applied Psychology, 2007[Jul], Vol 92[4], 1119-1130). The wrong grant number was cited in the author note. The author note indicated that the research was supported by National Institute for Occupational Safety and Health Grant OH013182. It should have cited grant number OH008335. (The following abstract of the original article appeared in record 2007-09571-017.) Work-family conflict research has focused almost exclusively on professional, White adults. The goal of this article was to expand the understanding of culture and industry in shaping experiences and consequences of work-family conflict. Using in-depth interview data (n = 26) and structured survey data (n = 200) from immigrant Latinos employed in the poultry processing industry, the authors evaluated predictions drawn from emerging models emphasizing the influence of cultural characteristics such as collectivism and gender ideology on work-family conflict. Results indicated that immigrant Latinos in poultry processing experienced infrequent work-to-family conflict; both the level and the antecedents of work-to-family conflict differed by gender, with physical demands contributing to greater conflict for women but not men. In addition, there was little evidence that work-family conflict was associated with health in this population. These results demonstrate how traditional models of work-family conflict need to be modified to reflect the needs and circumstances of diverse workers in the new global economy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory without awareness: Pigeons do not show metamemory in delayed matching to sample.

Metamemory, the ability to report on memory strength, is clearly established in rhesus macaques (Macaca mulatta) by converging evidence from several paradigms. In contrast, A. Inman and S. J. Shettleworth (1999) found no conclusive evidence of metamemory in pigeons. The authors studied pigeons further in 3 paradigms, with multiple tests of metamemory in each. Pigeons encountered a safe alternative to a matching-to-sample test either before (Experiment 2) or concurrently with (Experiment 3) the matching test. Choices of the safe option did not vary consistently with matching accuracy or change in trials with omitted samples in the way predicted for an animal with metamemory. In Experiment 4, confidence ratings following completion of the matching test also did not vary consistently as predicted by metamemory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Do not use the Friedewald formula to calculate LDL‐cholesterol in hypercholesterolaemic rats

Reputable calculations such as the Friedewald formula are used extensively to determine LDL‐cholesterol (LDL‐C) values from known total cholesterol, triacylglycerol and HDL‐cholesterol (HDL‐C) levels. To the best of our knowledge, however, the validity of this equation has not yet been confirmed in rats. The aim of the present study is to give some insights as to why this formula must be used carefully in rats, and to find cut‐off points below which this formula can be considered reliable. Sera of 54 rats with different cholesterol, triacylglycerol and HDL‐C levels were tested. LDL was isolated by ultracentrifugation and LDL‐C measured by an enzymatic colorimetric method and compared against LDL‐C obtained by the formula. In rats whose serum cholesterol was <100 mg/dL, or whose HDL‐C constituted ≥75% of total cholesterol, or whose cholesterol/phospholipids ratio was <1, or whose serum did not contain β‐VLDL, LDL‐C obtained by both methods did not significantly differ. Under other conditions, however, and particularly in hypercholesterolaemic rats who did present β‐VLDL, the results clearly show that the Friedewald formula overestimates LDL‐C levels. In conclusion, (VLDL + LDL)‐C instead of VLDL‐C and LDL‐C must be used when ultracentrifugation or other alternative methods are not available to measure LDL‐C in hypercholesterolaemic rats.     

Use of highly sensitive sublethal stress responses in the social amoeba Dictyostelium discoideum for an assessment of freshwater quality

In this work, the sensitivity of a battery of tests on the social amoeba Dictyostelium discoideum has been assessed within a freshwater toxicity study. The results obtained from the evaluation of survival and replication rate of D. discoideum were compared to those derived with a series of widely used tests for freshwater toxicity assessment, i. e. bioassays using Vibrio fischeri, Daphnia magna and Pseudokirchneriella subcapitata. The effects on sublethal endpoints, i.e. lysosomal membrane stability (LMS) and endocytotic rate, were analysed in conjunction with high-level endpoints to verify the potential to make a typical bioassay more sensitive. The field ecotoxicological investigation employing D. discoideum is part of a monitoring study assessing environmental quality of the Bormida River (Italy), subjected until recently to a chronic industrial pollution. The survey was carried out at several stations (upstream and downstream of a chemical factory outlet) in two different periods. In 2002, the results of chemical analyses performed on river water indicated no contamination. The ecotoxicological data obtained in this period showed that no evidence of biological effects was observed using V. fischeri and D. magna bioassays. In spite of the previous classical acute toxicity tests, significant differences in cell viability of D. discoideum were found. By analysing the effects measured on LMS and endocytotic rate, more relevant changes were observed for these sublethal stress biomarkers compared to survival. The chronic toxicity data showed significant changes in cell growth both of P. subcapitata and D. discoideum. Nevertheless, more sensitive and rapid responses were obtained when assessing the effects of exposure on D. discoideum. The chemical and ecotoxicological data obtained in 2006 indicated a full recovery of the quality of the river water (neither contamination nor toxicity found). Altogether, the results reported in this study underline that the use of a battery of biomarkers in conjunction with high-level endpoints may help follow the pollutant-induced stress syndrome in the organisms from early sublethal effects to starting mortality.