How to get the most out of two phosphorus chemistries. Studies on H-phosphonates

The biological importance and practical significance of phosphate esters and their analogues have been the major driving forces for research in various areas of synthetic organic phosphorus chemistry. In this Account, the authors' studies on the development of a comprehensive H-phosphonate methodology and the underlying chemistry for the preparation of biologically important phosphate esters and their analogues are briefly discussed.     

Effects of the abdominal belt on muscle-generated spinal stability and L4/L5 joint compression force

The goals of this study were (1) to determine the effects of abdominal belts on muscle-generated active lumbar spine stability, (2) to determine their effect on the subsequent joint compression force at L4/L5 and (3) to determine whether the effective stability of the spine could be predicted by the active spine stability and belt condition. Electromyographic (EMG) and trunk stiffness data from a previously reported experiment in which 10 subjects performed quick-release tasks (perturbation) with and without an abdominal belt were used as inputs to biomechanical models to estimate the active spine stability and effective stability of the spine, respectively. The subjects exerted isometric trunk flexion, extension and lateral bending trials at 0 and 80% of maximum intra-abdominal pressure when the resisted force was suddenly released. Wearing an abdominal belt had no significant effect on either the muscle-generated lumbar spine stability or the L4/L5 joint compression force in any direction. The effective stability of the spine was adequately predicted by the active spine stability and the effect of the belt, which accounted for approximately 34% of the effective spine stability. The study demonstrated that the abdominal belt contributed to the passive stability of the lumbar spine and did not change the active stability for tests performed within the same experimental session.     

Early and late results of surgical treatment in patients with primary mediastinal germ cell tumors]

A group of 37 patients--20 (54%) men and 17 (46%) women--aged 2-65, mean 31.6 years, was treated between 1978 and 1995 for different kinds of primary mediastinal germ cell tumours. In 14 (37.8%) of them a mature solid teratoma was diagnosed, in 13 (35.1%)--dermoid cyst, in 5 (13.5%)--malignant teratoma, in 1 (2.7%)--immature teratoma, in 4 (10.8%)--seminoma. Mediastinal tumour was removed completely in 30 (81.1%) patients, partially in 7 (18.9%). Out of 37 patients, 3 (8.1%) died during postoperative time. Out of 26 patients discharged after surgical removal of mature teratomas, all are alive and have been followed-up for 10 years (17 patients) or 5 years (6 patients). Out of 8 discharged after surgical removal of malignant neoplasm, 3 are alive and all of them had primary mediastinal seminoma. One of them has survived 17 years after complete resection, and two patients--7.5 years and 2 years after partial resection and radiotherapy. Mean survival time is 4 years and 2 months for all patients with malignant neoplasm.     

Data Flow Anomaly Detection

The occurrence of a data flow anomaly is often an indication of the existence of a programming error. The detection of such anomalies can be used for detecting errors and to upgrade software quality. This paper introduces a new, efficient algorithm capable of detecting anomalous data flow patterns in a program represented by a graph. The algorithm based on static analysis scans the paths entering and leaving each node of the graph to reveal anomalous data action combinations. An algorithm implementing this type of approach was proposed by Fosdick and Osterweil [2]. Our approach presents a general framework which not only fillls a gap in the previous algorithm, but also provides time and space improvements.     

A heuristic approach to the reinforcement-learning control of the one-dimensional model of an HTR core

Results of calculations are presented, which are concerned with applications of the heuristic linear reinforcement systems to the control of pebble-bed HTRs with the OTTO-loading scheme. Control results of three types of systems applications are presented and discussed. The systems were found to be satisfactory for control of the complex physical plants.     

Organotin compounds in the liver tissue of marine mammals from the Polish coast of the Baltic Sea

Butyltins (BTs) and phenyltins (PhTs) were determined in the livers of marine mammals found by-caught or stranded along the Polish coast of the Baltic Sea. During the investigation an original analytical method was developed. Butyltin compounds were detected in all the liver samples, whereas phenyltins were not detected in any of the samples. The total concentrations of BTs ranged from 43.9 to 7698 ng(Sn) x g(-1) dry weight. Age-related trends to accumulate BTs in immature porpoises were found. At the same time there were no male-female differences in BTs concentrations observed. No statistically significant spatial distribution differences were found between the locations corresponding to the open Baltic Sea waters and inside the Gulf of Gdańsk, which is characterized by high maritime activity. In comparison to butyltin levels in marine mammals from other geographic regions, the samples analyzed indicate a significant degree of tributyltin pollution along the Polish coast of the Baltic Sea. On the basis of a literature review, higher BT levels are usually found in waters close to highly industrialized areas, such as Japan, Hong Kong, and the United States.     

Computationally effective algorithm for robust weighted averaging

One of the greatest disadvantages of the weighted signal averaging method is its sensitivity to the presence of noise and outliers in data and the need to estimate the noise variance in all signal cycles. The robust weighted averaging method based on the epsilon-insensitive loss function is free of these disadvantages, but has a very high computational burden and requires a choice of the insensitivity parameter epsilon. In this study, a new computationally effective algorithm for robust weighted averaging with automatic adjustment of the insensitivity parameter is introduced.     

Open tubular immobilized metal ion affinity chromatography combined with MALDI MS and MS/MS for identification of protein phosphorylation sites

Protein phosphorylation is one of the most important known posttranslational modifications. Tandem mass spectrometry has become an important tool for mapping out the phosphorylation sites. However, when a peptide generated from the enzymatic or chemical digestion of a phosphoprotein is highly phosphorylated or contains many potential phosphorylation residues, phosphorylation site assignment becomes difficult. Separation and enrichment of phosphopeptides from a digest mixture is desirable and often a critical step for MS/MS-based site determination. In this work, we present a novel open tubular immobilized metal ion affinity chromatography (OT-IMAC) method, which is found to be more effective and reproducible for phosphopeptide enrichment, compared to a commonly used commercial product, Ziptip from Millipore. A strategy based on a combination of OT-IMAC, sequential dual-enzyme digestion, and matrix-assisted laser desorption/ionization (MALDI) quadrupole time-of-flight tandem mass spectrometry for phosphoprotein characterization is presented. It is shown that MALDI MS/MS with collision-induced dissociation can be very effective in generating fragment ion spectra containing rich structural information, which enables the identification of phosphorylation sites even from highly phosphorylated peptides. The applicability of this method for real world applications is demonstrated in the characterization and identification of phosphorylation sites of a Na(+)/H(+) exchanger fusion protein, His182, which was phosphorylated in vitro using the kinase Erk2.     

Estimation of scattering error in spectrophotometric measurements of light absorption by aquatic particles from three-dimensional radiative transfer simulations

We present an approach based on three-dimensional Monte Carlo radiative transfer simulations for estimating scattering error in measurements of light absorption by aquatic particles with a typical laboratory double-beam spectrophotometer. The scattering error is calculated by combining the weighting function describing the angular distribution of photon losses that are due to scattering on suspended particles with the volume scattering function of particles. We applied this method to absorption measurements made on marine phytoplankton, a diatom Thalassiosira pseudonana and a cyanobacterium Synechococcus. Assuming that the scattering phase function is described by the Henyey-Greenstein formula, we determined the backscatter probability of phytoplankton, which yields the best correction for scattering error at a light wavelength of 750 nm, where true absorption is null. The backscattering ratio estimated for both phytoplankton species is significantly higher than previously reported data based on Mie-scattering calculations for homogeneous spheres. Depending on the type of particles, the corrected absorption spectra obtained with our method may be similar or significantly different from spectra obtained with the null-point correction based on wavelength-independent scattering error.     

Using the primal-dual interior point algorithm within the branch-price-and-cut method

Branch-price-and-cut has proven to be a powerful method for solving integer programming problems. It combines decomposition techniques with the generation of both columns and valid inequalities and relies on strong bounds to guide the search in the branch-and-bound tree. In this paper, we present how to improve the performance of a branch-price-and-cut method by using the primal-dual interior point algorithm. We discuss in detail how to deal with the challenges of using the interior point algorithm with the core components of the branch-price-and-cut method. The effort to overcome the difficulties pays off in a number of advantageous features offered by the new approach. We present the computational results of solving well-known instances of the vehicle routing problem with time windows, a challenging integer programming problem. The results indicate that the proposed approach delivers the best overall performance when compared with a similar branch-price-and-cut method which is based on the simplex algorithm.