A simple convenient biological dosimeter for monitoring solar UV-B radiation

The use of dry Bacillus subtilis spores as a biological dosimeter for the monitoring of solar UV-B (290-330 nm) radiation was described. Our field tests had supported the utility of this dosimeter as a reproducible and reliable sunlight dosimeter.     

A resolution of glutamic acid

N-Carbobenzoxy-dl-glutamic acid was asymmetrically hydrolyzed by hog kidney acylase to l-glutamic acid ([α]_D = +31.9 °) and N-carbobenzoxy-d-glutamic acid ([α]_d = + 7.5 °). On catalytic hydrogenation of the latter, d-glutamic acid ([α]_d = ?31.5 °) was obtained readily and in high yield.     

A glutamic acid producingStreptomyces sp

Following the bioautographic technique, a strain ofStreptomyces sp. has been isolated producingL-glutamic acid. The strain is able to grow and produce glutamate in mineral salt medium, but supplementation with yeast extract improved the yield.     

Derivatives of glutamic acid as new surfactants>

Summary. Starting from glutamic acid, different types of surfactants have been synthesised by using original trimodular strategies. Monosubstituted zwitterionic amides of glutamic acid obtained with excellent yields show good surface activity. The grafting of a second hydrophobic side-chain leads to bicatenar cationic surfactants or to disubstituted nonionic cyclic compounds. In order to reduce the hydrophobic character of the bicatenar surfactants, a second synthetic method has been developed, allowing the introduction of a polar sugar group into these molecules. The surfactant properties of several of the products have been determined by physico-chemical methods such as surface tension measurements and compression isotherm studies by means of a Langmuir balance.     

Real-time patient radiation dosimeter for use in interventional radiology

There is currently no effective real-time patient dosimeter available for use in interventional radiology (IR). We conducted a feasibility study in a clinical setting to investigate the use of the new dosimeter using photoluminescence sensors during procedures. Reference dosimeters were set at almost the same position of the prototype dosimeter sensors.We found excellent correlations between the reference measurements and those of the prototype dosimeter (r² = 0.950). The sensor of the new dosimeter does not interfere with the IR procedure. The new dosimeter will be an effective tool for the real-time measurement of patient skin doses during IR.     

A fuzzy expert system for the optimization of glutamic acid production

A fuzzy expert system was developed to allow the effective use of semi-quantitative or imprecise information in the determination of the optimal operating conditions of a fermentation process. The system incorporated fuzzy relations representing both the trends of experimental data and semi-quantitative information obtained from the literature. The inference method used consisted primarily of search and reasoning based on fuzzy set theory. The resulting expert system incorporated a generalized inference engine designed to deal with various types of fermentation processes, it only being necessary to alter the knowledge database in order to adapt the system to process modifications. The construction of the knowledge database from experimental data or semi-quantitative information was designed to be carried out semi-automatically using a graphic computer tool.The expert system was applied to the optimization of glutamic acid production by fermentation. The optimal conditions predicted by the expert system were found experimentally to give maximum production.List of Symbols A, B names of objects - A _i , B _i linguistic level of A and B, respectively - E₁, E₂ ordinary sets - I depth of search for inference - I _M maximum of I - M, X, Y names of sets - R ₁, R ₂ fuzzy relations - P_total g amount of glutamic acid production - Pen⁺ h penicillin addition time - S_vp1 h^–1 specific rate of glutamic acid production in 1st production phase - S_vp2 h^–1 specific rate of glutamic acid production in 2nd production phase - T _growth h growth period - T _lag h lag time - T _plag h lag time of production defined in Fig. 6 - T _p1 h period of 1st production - T _p2 h period of 2nd production - T _total h total production time - X _p g average cell mass of production phase - x, y, z real numbers - max(x, y) or x y maximum of x and y - min(x, y) or x y minimum of x and y     

Controlled release of macromolecules and pharmaceuticals from synthetic polypeptides based on glutamic acid

Biocompatible, biodegradable copolymers of glutamic acid and ethyl glutamate were evaluated for their permeability to proteins ranging in molecular weight from 12,300 to 69,000. The results showed that the copolymers were sufficiently permeable that they could be used for the preparation of implantable, controlled-release systems capable of releasing therapeutic amounts of high-molecular-weight drugs.     

A model of enzymatic decarboxylation of glutamic acid

Interaction of glutamate decarboxylase with its adequate substrate and some quasi-substrates was studied by spectrokinetic, quantum-chemical and some other approaches. It was shown that in the course of decarboxylation an abortive transamination of pyridoxal-5'-phosphate leading to the enzyme inactivation does occur. Identification of intermediate coenzyme-substrate complexes allowed to formulate a model of enzymatic decarboxylation taking into account both the main and abortive reactions. The analysis of electronic structure of the intermediates revealed some of the factors determining the functional specificity of the reaction under study.     

A new neural framework for visuospatial processing

The division of cortical visual processing into distinct dorsal and ventral streams is a key framework that has guided visual neuroscience. The characterization of the ventral stream as a 'What' pathway is relatively uncontroversial, but the nature of dorsal stream processing is less clear. Originally proposed as mediating spatial perception ('Where'), more recent accounts suggest it primarily serves non-conscious visually guided action ('How'). Here, we identify three pathways emerging from the dorsal stream that consist of projections to the prefrontal and premotor cortices, and a major projection to the medial temporal lobe that courses both directly and indirectly through the posterior cingulate and retrosplenial cortices. These three pathways support both conscious and non-conscious visuospatial processing, including spatial working memory, visually guided action and navigation, respectively.     

Age determination based on amino acid racemization: A new possibility

Summary A method has been developed to determine the age of fossil bone samples based on amino acid racemization (AAR). Approximately one hundred fossil bone samples of known age from Hungary were collected and analysed for D- and L-amino acids. As the racemization of amino acids is affected by temperature, pH, metal content of the soil, and time passed since death, these factors were eliminated by comparing the estimated age to age determined by the radiocarbon method. Determining the D- and L-amino acid contents in samples of known age, determining the half life of racemization and plotting the D/L ratio as a function of time, calibration curves were obtained. These curves can be used for the age estimation of samples after determining their D- and L-amino acid content. The D/L ratio for 2 to 3 amino acids was determined for each sample and the mean value of estimated ages based on calibration curves was considered to estimate age of the fossil samples.     

A model of radiation action based on nanodosimetry and the application to ultra-soft X-rays

Radiation and Environmental Biophysics - A radiation action model based on nanodosimetry is presented. It is motivated by the finding that the biological effects of various types of ionizing...