Model of a measurement error distribution function

Translated from Izmeritel'naya Tekhnika, No. 8, pp. 6–9, August, 1989.     

Structure of the turbulent mixing zone on the boundary of two gases accelerated by a shock wave

Moscow. Translated from Fizika Goreniya i Vzryva, Vol. 26, No. 3, pp. 71–77, May–June, 1990.     

Properties of Anthocyanins from Grape Cell Culture

Color and thermal- and pH-stability of anthocyanins from a grape cell suspension culture were compared with those of commercial food colorants using Hunter and spectrophotometric analysis. At pH 3, grape cell anthocyanins showed color vividness (Chroma) similar to red cabbage and higher than that of other samples and a hue (Theta) similar to purple corn and redder than other samples. Brown oxidized phenolics were absent from the cell culture and red cabbage preparations, but were found in other samples. Color loss during incubation at 30 and 95°C, pH 3 and during an increase in pH from 3 to 5 was more severe for cell culture than red cabbage anthocyanins probably indicating they were intrinsically more sensitive.     

Pulmonary scintigraphy at the bedside in intensive care patients with suspected pulmonary embolism

We report the results of a longitudinal study aimed at better defining concomitant changes of both bone mineral density (BMD) and of four independent markers of bone turnover (serum osteocalcin, serum alkaline phosphatase activity, fasting urinary hydroxyproline/creatinine and calcium/creatinine ratio) following natural menopause. The results obtained indicate that, within a relatively short period of time since cessation of gonadal function, conventional markers of bone turnover behave differently. In fact, while the mean values of hydroxyproline/creatinine ratio (felt to be a marker of bone resorption) rise immediately at the first control (19.7 +/- 11.7 months), the bone formation markers gradually increase and, as far as serum osteocalcin levels are concerned, this increment appears to be long-lasting. As a result of these changes, a negative skeletal balance follows, which is documented by the prolonged reduction of bone mineral density during the entire observation period. Mean +/- SD % measured yearly bone loss was -2.83 +/- 2.6. There was a highly significant correlation between initial and final BMD values (r = 0.908, p < 0.001; r2 = 82.5) and a weak inverse correlation (r = -0.298, p < 0.046) between initial serum alkaline phosphatase values and % yearly bone loss. In conclusion, measurement of the biological indices of bone remodelling following natural menopause indicate that the increase in osteogenesis is delayed compared to that of bone resorption; furthermore, in the immediate postmenopausal period, the actual bone mass should be considered the best predictor of future bone mass. The inverse correlation found between % yearly bone loss and serum alkaline phosphatase values seems to emphasize the importance of increased bone turnover as an independent predictor of bone loss.     

Characterization of the ATP- and GTP-specific succinyl-CoA synthetases in pigeon. The enzymes incorporate the same alpha-subunit

Two succinyl-CoA synthetases, one highly specific for GTP/GDP and the other for ATP/ADP, have been purified to homogeneity from pigeon liver and breast muscle. The two enzymes are differentially distributed in pigeon, with only the GTP-specific enzyme detected in liver and the ATP-specific enzyme in breast muscle. Based on assays in the direction of CoA formation, the ratios of GTP-specific to ATP-specific activities in kidney, brain, and heart are approximately 7, 1, and 0.1, respectively. Both enzymes have the characteristic alpha- and beta-subunits found in other succinyl-CoA synthetases. Studies of the alpha-subunit by electrophoresis, mass spectrometry, reversed-phase high performance liquid chromatography, and peptide mapping showed that it was the same in the two enzymes. Characterization of the beta-subunits by the same methods indicated that they were different, with the tryptic peptide maps providing evidence that the beta-subunits likely differ along their entire sequences. Because the two succinyl-CoA synthetases incorporate the same alpha-subunit, the determinants of nucleotide specificity must reside within the beta-subunit. Determination of the apparent Michaelis constants showed that the affinity of the GTP-specific enzyme for GDP is greater than that of the ATP-specific enzyme for ADP (7 versus 250 microM). Rather large differences in apparent Km values were also observed for succinate and phosphate.     

Long-term analysis of conventional coronary balloon angioplasty and an initial "stent-like" result. The NHLBI PTCA Registry

Researchers examining clinical decision-making often explored the role of the nurse's experience. In these studies, experience was conceptualized as either the time spent in nursing or the knowledge which came from practice. This paper reports on the conceptualization of the nurse's experience emerging from a grounded theory study describing one decision-making process: 'knowing the patient'. Data included in-depth interview text, participant observation fieldnotes, and documents. Data were analysed using the constant comparative method and open, axial and selective coding techniques. In the analysis, the nurse's experience was conceptually defined as 'the application of that learned from previous practice situations'. Three attributes of the nurse's experience emerged. These included a focus on the patient, confidence in practice, and knowledge of antecedents and consequences of similar patient situations. Each aspect enhanced the individualization of nursing interventions. The findings are related to other investigations in nursing and insights for practice are offered.     

Impact toughness of ship steels and estimation of their susceptibility to brittle fracture

The present paper concerns a new method for determining the cold-brittleness temperatureT _cb in tests for impact toughness. Results of estimation of metal quality based on conventional characteristics and the suggested parameter of resistance to defects are compared for ship steels 10KhSND and 12KhN3. Impact toughness is essentially an integral characteristic of a metal. The energy capacity of fracture depends on the strength and ductility simultaneously, as well as on the test conditions and the shape of the specimen, which in many cases makes estimation of metal quality ambiguous. The authors consider nontraditional approaches to determination of the embrittlement action of various stress concentrators. The aim of the work consists in establishing a relation between the universally used mechanical properties determined in impact toughness tests and toughness parameters such asK _t (toughness coefficient) andD ₂ (resistance to defects). Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 27–30, March, 1997.     

Inositol 1,4,5-trisphosphate [correction of tris-phosphate] activation of inositol trisphosphate [correction of tris-phosphate] receptor Ca2+ channel by ligand tuning of Ca2+ inhibition

Inositol 1,4,5-trisphosphate (IP3) [corrected] binding to its receptors (IP3R) in the endoplasmic reticulum (ER) activates Ca2+ release from the ER lumen to the cytoplasm, generating complex cytoplasmic Ca2+ concentration signals including temporal oscillations and propagating waves. IP3-mediated Ca2+ release is also controlled by cytoplasmic Ca2+ concentration with both positive and negative feedback. Single-channel properties of the IP3R in its native ER membrane were investigated by patch clamp electrophysiology of isolated Xenopus oocyte nuclei to determine the dependencies of IP3R on cytoplasmic Ca2+ and IP3 concentrations under rigorously defined conditions. Instead of the expected narrow bell-shaped cytoplasmic free Ca2+ concentration ([Ca2+]i) response centered at approximately 300 nM-1 microM, the open probability remained elevated (approximately 0.8) in the presence of saturating levels (10 microM) of IP3, even as [Ca2+]i was raised to high concentrations, displaying two distinct types of functional Ca2+ binding sites: activating sites with half-maximal activating [Ca2+]i (Kact) of 210 nM and Hill coefficient (Hact) approximately 2; and inhibitory sites with half-maximal inhibitory [Ca2+]i (Kinh) of 54 microM and Hill coefficient (Hinh) approximately 4. Lowering IP3 concentration was without effect on Ca2+ activation parameters or Hinh, but decreased Kinh with a functional half-maximal activating IP3 concentration (KIP3) of 50 nM and Hill coefficient (HIP3) of 4 for IP3. These results demonstrate that Ca2+ is a true receptor agonist, whereas the sole function of IP3 is to relieve Ca2+ inhibition of IP3R. Allosteric tuning of Ca2+ inhibition by IP3 enables the individual IP3R Ca2+ channel to respond in a graded fashion, which has implications for localized and global cytoplasmic Ca2+ concentration signaling and quantal Ca2+ release.     

Comparison of the PspA sequence from Streptococcus pneumoniae EF5668 to the previously identified PspA sequence from strain Rx1 and ability of PspA from EF5668 to elicit protection against pneumococci of different capsular types

PspA (pneumococcal surface protein A) is a serologically varied virulence factor of Streptococcus pneumoniae. In mice, PspA has been shown to elicit an antibody response that protects against fatal challenge with encapsulated S. pneumoniae, and the protection-eliciting residues have been mapped to the alpha-helical N-terminal half of the protein. To date, a published DNA sequence for pspA is available only for S. pneumoniae Rx1, a laboratory strain. PspA/EF5668 (EF5668 indicates the strain of origin of the PspA) is serologically distinct from PspA/Rx1. Sequencing of the gene encoding PspA/EF5668 revealed 71% identity with that of PspA/Rx1. The greatest amount of divergence between the two proteins was seen in their alpha-helical portions, which are surface exposed and probably under selective pressure to diversify serologically. In spite of the diversity within the alpha-helical regions of PspAs, we have observed that recombinant PspA (rPspA)/EF5668, like rPspA/Rx1, can elicit cross-protection against pneumococci of different capsular and PspA serological types.