VISCOSITY STUDIES OF SYSTEM CaO–MgO–Al2O3–SiO2: 1, 40% SiO2*

The measurement of glass viscosities at elevated temperatures with an oscillating cylinder-type viscometer is described. Viscosity data are presented covering those compositions in the CaO–MgO–Al₂O₃–SiO₂ system which contain 40% SiO₂ and which are liquid at 1500°C. The pattern of the system of isokoms presented indicates that viscosity is closely related to the ratio of basic to acidic components. Theoretical aspects of the variation of viscosity with composition in silicate-aluminate systems are discussed in terms of silica-alumina polymers.     

A Cross-Sectional and Longitudinal Analysis of Pre-Diagnostic Blood Plasma Biomarkers for Early Detection of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a major cause of cancer death that typically presents at an advanced stage. No reliable markers for early detection presently exist. The prominent tumor stroma represents a source of circulating biomarkers for use together with cancer cell-derived biomarkers for earlier PDAC diagnosis. CA19-9 and CEA (cancer cell-derived biomarkers), together with endostatin and collagen IV (stroma-derived) were examined alone, or together, by multivariable modelling, using pre-diagnostic plasma samples (n = 259 samples) from the Northern Sweden Health and Disease Study biobank. Serial samples were available for a subgroup of future patients. Marker efficacy for future PDAC case prediction (n = 154 future cases) was examined by both cross-sectional (ROC analysis) and longitudinal analyses. CA19-9 performed well at, and within, six months to diagnosis and multivariable modelling was not superior to CA19-9 alone in cross-sectional analysis. Within six months to diagnosis, CA19-9 (AUC = 0.92) outperformed the multivariable model (AUC = 0.81) at a cross-sectional level. At diagnosis, CA19-9 (AUC = 0.995) and the model (AUC = 0.977) performed similarly. Longitudinal analysis revealed increases in CA19-9 up to two years to diagnosis which indicates a window of opportunity for early detection of PDAC.     

Provenance studies of archaeological ceramics from Mar-Takla (Ain-Minin, Syria) using radioisotope X-ray fluorescence method

The radioisotope X-ray fluorescence method was applied to studies of the provenance of the ceramics fragments originated from the Mar-Takla site in Syria.The samples were irradiated 1000s by a ^109Cd radioisotope source and 13 elements (Ca,Ti,Mn,Fe,Zn,Ga,As,Rb,Sr,Y,Zr,Nb,and Pb)were determined in 35 samples.The data were subjected to two multivariate statistical methods,cluster and principal components analysis(PCA).It was shown from the combination of the statistical techniques and the determination of elemental composition of the samples that 94% of the ceramic samples analyzed can be considered to be manufactured using two sources of raw materials.     

Effect of substrate concentration on continuous Photo-fermentative hydrogen production from lactate using Rhodobacter sphaeroides

The information on continuous operation and the use of actual waste as a feedstock are essential for the practical application of photo-fermentative H₂ production. For the first 200 days, continuous H₂ production from lactate was attempted using purple non-sulfur (PNS) bacteria, Rhodobacter sphaeroides KD131, under an illumination of 110 W/m². During the continuous operation, 30% of the fermenter volume was replaced by fresh feedstock once a day, and substrate concentration was gradually increased from 5 mM to 30 mM. H₂ production was negligible at 5 mM, which was ascribed to the fact that the electrons contained in lactate were mostly consumed for cell growth and soluble microbial products (SMPs) production. As lactate concentration increased, H₂ production gradually increased and reached a maximum at 20 mM, showing a substrate conversion efficiency (SCE) of 38%, a H₂ yield of 2.3 mol H₂/mol lactate_added, and a H₂ production rate of 309 mL H₂/L-fermenter/d. Further increases of lactate concentration resulted in a drop of H₂ production (<1.0 mol H₂/mol lactate_added). When the feedstock was changed to actual waste obtained from a 1-day lactate fermentation of food waste, stable H₂ production was maintained, but showed a decreased SCE of 24%. It was speculated that the low performance was due to the fact that actual waste contained not only pure lactate but also other organic compounds that could not be utilized by PNS bacteria. In addition, compared to feeding with pure lactate, the electron consumption to the cell growth was higher in feeding with actual waste, which led to the lower performance.     

Cause and effect analysis by fuzzy relational equations and a genetic algorithm

This paper proposes using a genetic algorithm as a tool to solve the fault diagnosis problem. The fault diagnosis problem is based on a cause and effect analysis which is formally described by fuzzy relations. Fuzzy relations are formed on the basis of expert assessments. Application of expert fuzzy relations to restore and identify the causes through the observed effects requires the solution to a system of fuzzy relational equations. In this study this search for a solution amounts to solving a corresponding optimization problem. An optimization algorithm is based on the application of genetic operations of crossover, mutation and selection. The genetic algorithm suggested here represents an application in expert systems of fault diagnosis and quality control.     

Myopathy-Sensitive G-Actin Segment 227-235 Is Involved in Salt-Induced Stabilization of Contacts within the Actin Filament

Formation of stable actin filaments, critically important for actin functions, is determined by the ionic strength of the solution. However, not much is known about the elements of the actin fold involved in ionic-strength-dependent filament stabilization. In this work, F-actin was destabilized by Cu²⁺ binding to Cys374, and the effects of solvent conditions on the dynamic properties of F-actin were correlated with the involvement of Segment 227-235 in filament stabilization. The results of our work show that the presence of Mg²⁺ at the high-affinity cation binding site of Cu-modified actin polymerized with MgCl₂ strongly enhances the rate of filament subunit exchange and promotes the filament instability. In the presence of 0.1 M KCl, the filament subunit exchange was 2–3-fold lower than that in the MgCl₂-polymerized F-actin. This effect correlates with the reduced accessibility of the D-loop and Segment 227-235 on opposite filament strands, consistent with an ionic-strength-dependent conformational change that modulates involvement of Segment 227-235 in stabilization of the intermonomer interface. KCl may restrict the mobility of the α-helix encompassing part of Segment 227-235 and/or be bound to Asp236 at the boundary of Segment 227-235. These results provide experimental evidence for the involvement of Segment 227-235 in salt-induced stabilization of contacts within the actin filament and suggest that they can be weakened by mutations characteristic of actin-associated myopathies.