Scanning ion conductance microscopy of living cells

Currently there is a great interest in using scanning probe microscopy to study living cells. However, in most cases the contact the probe makes with the soft surface of the cell deforms or damages it. Here we report a scanning ion conductance microscope specially developed for imaging living cells. A key feature of the instrument is its scanning algorithm, which maintains the working distance between the probe and the sample such that they do not make direct physical contact with each other. Numerical simulation of the probe/sample interaction, which closely matches the experimental observations, provides the optimum working distance. The microscope scans highly convoluted surface structures without damaging them and reveals the true topography of cell surfaces. The images resemble those produced by scanning electron microscopy, with the significant difference that the cells remain viable and active. The instrument can monitor small-scale dynamics of cell surfaces as well as whole-cell movement.     

Apolipoprotein B and AI distributions in the United States, 1988-1991: results of the National Health and Nutrition Examination Survey III (NHANES III)

Serum apolipoproteins (apo) B and AI were measured in a probability sample of the noninstitutionalized US civilian population, ages > or = 4 years, which included non-Hispanic whites, non-Hispanic blacks, and Mexican-Americans. Apo B concentrations were the same in males and females, lower in black males than in other males, low in childhood (approximately 0.80 g/L) and increasing to approximately 1.2 g/L in adults, and higher in younger women on hormones. Apo AI was higher in females than males, higher in blacks than in others, remained constant from childhood to adulthood (approximately 1.35 g/L) in males, but increased with age (approximately 1.30 g/L to approximately 1.55 g/L) in females, and was higher in women taking hormones. These are the first national probability estimates of apo B and apo AI in the US and are referable to the WHO-IFCC First International Reference Materials for apo AI and B.     

Phase-Based Frequency Estimation: A Review

Fowler, M. L., Phase-Based Frequency Estimation: A Review, Digital Signal Processing12 (2002) 590–615This paper provides a review of efficient frequency estimation methods that use only the phases of the signal samples. Such methods continue to attract attention in various applications such as radar, electronic warfare, and next-generation communication systems. We present the details of the basic phase-based method, including its theoretical basis and its performance characterization, and provide an integrated presentation of its threshold behavior. In addition, we review several improvements, implementations, and extensions of the basic method and give some new results and viewpoints. In particular, the paper shows that Kay's method is equivalent to Tretter's method together with a simple phase unwrapping algorithm (thus, Kay's method does not really avoid phase unwrapping errors). We also show that a phase-based method for estimating chirp parameters has an advantage when applied to sinusoids: improved threshold behavior. We present a method that, unlike most of the other phase-based methods, can start processing the signal before knowing the number of samples.     

Anti-plasmodial and anti-trypanosomal activity of synthetic naphtho[2,3-b]thiopen-4,9-quinones

Naphtho[2,3-b]thiophen-4,9-quinone and five derivatives were prepared using the Friedel-Crafts reaction and tandem-lithiation of aromatic diethylamides. These quinones were evaluated for their trypanocidal and anti-plasmodial activities by their effects on: (1) growth of epimastigote forms of Trypanosoma cruzi in vitro, (2) lysis of trypomastigote forms of T. cruzi in murine blood, (3) growth of Plasmodium falciparum in vitro, and (4) inhibition of the recombinant enzyme trypanothione reducatase. The parent compound, naphtho[2,3-b]thiophen-4,9-quinone (3a), was among the most active quinone tested in vitro against P. falciparum at 0.2 microM. However, it was inactive against P. berghei-infected mice treated with 2.3 mmol/kg daily for 5 days. Most of the quinones prepared were active against T. cruzi epimastigotes in culture but exhibited weak activity at 4 degrees C against trypomastigotes in murine blood as well against the enzyme trypanothione reducatase. Further structural modifications will be necessary to improve the in vivo activity of the naphthothiophenquinones.     

MMPI differences between alcoholics and drug abusers: Effect of age and race.

Inpatients in Veterans Administration substance-abuse treatment programs voluntarily took the Minnesota Multiphasic Personality Inventory (MMPI) as part of a routine clinical evaluation. The alcohol-dependence-only group (n?=?207) were older (M?=?49.6 years) and had a higher percentage of White Ss (72.9%) than did either the drug-dependence group (n?=?49, M?=?32.9 years, Whites?=?53.1%) or a mixed alcohol- and drug-dependence group (n?=?160, M?=?35.0 years, Whites?=?60.0%). Previously reported differences between alcoholics and drug abusers in depression and psychopathy were obtained when age and race were not used as covariates, but no differences were found when the effects of age and race were statistically controlled. Mixed alcohol and drug abusers had somewhat more pathological MMPI scores than did alcoholics, even when effects due to age and race were partialed out. (PsycINFO Database Record (c) 2010 APA, all rights reserved)