Optimal Physical Conditions Research Articles

A challenge for high-precision radiation therapy: the case for hadrons.

Developments in Hadron therapy, i.e., fast neutrons, protons, pions, heavy ions and boron neutron capture therapy are reviewed. For each type of particle, operational and closed facilities are listed as well as planned new facilities. Improvements in clinical results have always been linked to technological developments and better physical selectivity of the irradiation. Exploring the benefit of further improvement in dose localization expected from protons and conformal therapy is the challenge for the coming years. The radiobiological rationale for high-LET radiation in cancer treatment, proposed in the fifties, is still valid and has not been contradicted by recent radiobiological findings. This justifies the planning of a therapy facility where protons and heavy ions (carbon ions) could be applied, under optimal physical and technical conditions. Appropriate selection between low- and high-LET radiation for a particular tumor is indeed a radiobiological problem, independent of technical development.

Environmental and nutritional factors which regulate population dynamics and toxin production in the dinoflagellate Alexandrium catenella

The effects of environmental and nutritional factors on population dynamics and toxin production were examined in Alexandrium catenella, maintained in enriched K media in laboratory cultures. Starting with a density of 50 cell ml−1, the dinoflagellate population typically showed a lag phase and an exponential growth phase which lasted 14 days each, and then entered the stationary phase, with a maximal capacity of 12–18,000 cell ml−1. Population densities showed distinct diurnal patterns, with population growth beginning 2-4 hours in darkness. The optimal physical conditions for growth were pH 8.5, salinity of 30–35%, temperature of 20-25°C, and photoperiod of 14//10D to 16L/8D. The cell cycle was determined by flow cytometry on synchronized batch cultures maintained at optimal pH, salinity, temperature and under 5 different photoperiod regimes. It was found that the G1 phase was timed to end at approximately 3 h after onset of darkness, and the G2/M phase had begun at 4 hours. Nutrient supply markedly affected population growth. Under optimal physical conditions, the optimal concentrations for macronutrients and micronutrients were: NH4 + 0.025–0.2 mM, NO3 − 0.22–8.83 mM, glycerophosphate 0.04–0.06 mM, silicate 0.1–0.54 mM; FeEDTA 0.07–0.11 mM; Co 0.1 μM, Cu 0.005–0.04 μM; Mn 0.22–7.2 μM; Mo 0.03–0.6 μM; Se 0.02–0.1 μM; Zn 0.04–1.6 μM; thiamin 0.075–6 μM; vitamin B12 0.0004–0.004 μM; biotin 0.007–0.015 μM; EDTA 5–40 μM.

A diagnostic test for heparin-induced thrombocytopenia: detection of platelet microparticles using flow cytometry.

Based on our previous observation that heparin-induced thrombocytopenia (HIT) sera can generate platelet microparticles from washed platelets in a heparin-dependent fashion, we developed a test for HIT using flow-cytometry to measure heparin-dependent platelet microparticle formation. During the developmental phase of the assay the optimal physical conditions for microparticle generation were defined. 133 sera were then evaluated using the microparticle assay and the serotonin release assay to determine the threshold for defining a positive result that gave optimal sensitivity and specificity. The microparticle assay was then prospectively evaluated against the serotonin release assay in 202 sera referred to our laboratory for HIT testing. Overall agreement between the two assays was 96% (Cohen's kappa = 0.91). When the clinical data were reviewed on patients whose sera gave discrepant results between the two assays, no case of HIT was detected by one assay and missed by the other. The platelet microparticle assay is as accurate as the serotonin release assay and may be a useful non-radioactive test for HIT.

Selection of Optimal Physical Conditions for Mass Propagation of Catolaccus grandis (Hymenoptera: Pteromalidae) Aided by Regression

Effects of temperature, relative humidity, and photoperiod on developmental time, reproductive potential, and rate of increase of Catolaccus grandis (Burks) were evaluated under laboratory conditions. Polynomial multiple regression models were used to estimate optimal levels of the 3 physical factors studied to maximize the reproductive potential and rate of increase of C. grandis . Net reproductive rate (Ro) was used as a measure of reproductive potential, and its maximum value occurred at 27°C, 63% RH, and a photoperiod of 16:8 (L:D) h. Maximum value of the intrinsic rate of increase (rm) of C. grandis occurred at 29°C, 66% RH, and 16:8 (L:D) h. Shortest developmental time within the physical factor levels studied was estimated to occur at 30°C, 67% RH, and 16:8 (L:D) h. Fecundity of C. grandis is maximized at 26°C, 68% RH, and a photoperiod of 16:8 (L:D) h according to regression model estimates.

Macroscopic phototactic behavior of the purple photosynthetic bacterium Rhodospirillum centenum.

Most photosynthetic microorganisms have the capability of photosensing light quality and intensity. Movement of motile photosynthetic microorganisms to locales that offer optimal physical and chemical conditions for light-dependent growth provides obvious selective advantages. Among phototrophs, many cyanobacteria and algae migrate towards or away from the direction of light, a process termed phototaxis. In contrast, anoxygenic photosynthetic bacteria are believed to respond to changes in light intensity in a manner that is not related to the direction of light, a process that is often described by the term "photophobic". We recently reported that "swarm colonies" of the purple photosynthetic bacterium Rhodospirillum centenum are capable of macroscopically visible phototactic behavior. In the present study we further characterize the phototactic behavior of R. centenum swarm colonies and provide an action spectrum that delineates regions of the spectrum that elicit positive and negative phototaxis.

Antibiotic production by the immobilized cyanobacterium,Scytonema sp. TISTR 8208, in a seaweed-type photobioreactor

A photobioreactor was constructed using either anchored polyurethane foam strips (1 × 1 × 40 cm, PU-strips) fixed on a stainless-steel ring to prevent flotation, or free-floating polyurethane foam blocks (1 × 1 × 1 cm, PU-blocks) as biomass supporting materials (BSM). The cyanobacterium,Scytonema sp. TISTR 8208, which produces an antibiotic, was immobilized onto PU-strips or -blocks. The free-floating PU-blocks could immobilize only about 70% of the total cells, while the anchored PU-strips could immobilize as much as 97%. PU-strips were chosen as the BSM and we named this type of reactor, seaweed-type bioreactor (STB). Optimal physical conditions for antibiotic production were determined in the STB. Inoculum density was 0.4 g l−1 and cells were sparged with air containing 5% CO2 circulated at the gas flow rate of 250 ml min−1 and illuminated at a light intensity of 200 μmol photon m−2 s−1. The production of antibiotic could be increased 3-fold.

The Extraction of Smooth Muscle Contractile and Noncontractile Proteins from the Rat Small Intestine: Measurement of Protein Synthesis and Effects of Ethanol Toxicity

An investigation was made into the optimum conditions for the extraction and measurement of intestinal smooth muscle contractile proteins of laboratory rats. Isolation of the seromuscular layer was achieved by "mucosal stripping" (using a glass slide); isolation of contractile proteins were achieved by differential solubility (using high and low ionic buffers and ultracentrifugation). Histological evidence revealed that after mucosal striping all cells of the longitudinal and circular muscle layers of the seromuscular region remained intact. Assay of brush-border marker enzyme activities confirmed that mucosal striping did indeed remove the mucosa and there was very little villus contamination of the smooth muscle tissue preparations. Optimum physical conditions for the isolation of seromuscular and mucosal myofibrillary proteins were identified. We ascertained that considerable amounts of myofibrillarly proteins reside in the mucosa, but could be adequately separated by mucosal striping. Improved recoveries of purified contractile proteins necessitated the inclusion of protease inhibitors during all processing steps. Using the optimum method, polyacrylamide gel electrophoresis of contractile proteins showed that the predominant smooth muscle contractile proteins, i.e., myosin heavy chain, actin, tropomyosin, and myosin light chains, were indeed preferentially isolated by our methodology. Using these techniques we demonstrated that the synthesis rates of intestinal contractile proteins were reduced by acute ethanol dosage. These results may be responsible for, or reflect, alcohol-induced defects in intestinal motility.

Flow-injection and continuous-flow systems to determine antimony(III) and antimony(V) by hydride generation atomic absorption spectrometry

Antimony(III) and -(V) were determined by flow-injection—hydride generation atomic absorption spectrometry (AAS) and by continuous-flow—hydride generation AAS and the analytical performances of the methods were compared. The optimum physical and chemical conditions for hydride generation and transport are given for the two methods. Both methods are more sensitive than the batch system. Total antimony was determined in sea water, but antimony(III) was below the detection limit (7 pg) of the proposed method.

Factors affecting areole activation in vitro in the cactus Sulcorebutia alba Rausch

A cultivation system was developed to study areole activation (AA) in explants of the cactus Sulcorebutia alba Rausch. Explants containing three areoles were cut from the central piece of the cladodes, which were grown in vitro. The optimal culture medium for AA consisted of macro-salts according to Murashige and Skoog at a strength of 1.5, MS micro-salts at full strength except iron, NaFeEDTA 25 mg l −1, sucrose 2.5%, BA 0.25–1 mg l −1, Daichin agar 0.5% and pH 5.5. Cytokinin was an essential prerequisite for AA; BA yielded best results, followed by kinetin. The cytokinins PBA, 2iP and IPA were not suitable as they gave rise to heavy callus formation. Optimal physical growth conditions for AA were a temperature of 27°C and an irradiance of 2.3–5 W m −2 (photosynthetically active radiation).

Optimisation and regularisation in microwave diagnostics of semiconductors having smooth and unsmooth functions

A new microwave iterative technique for obtaining the inhomogeneous profile of semiconductor permittivity and conductivity is optimised. The optimum physical conditions for applying the gradient method in solving microwave inverse problems are studied and underlined. A new regularisation approach is applied to improve the profiles of oscillating solutions. Numerical experiments are used to prove the validity of this technique in solving ill-posed problems.

In Vitro Secretion of Pectolytic Enzymes by Xanthomonas campestris

Summary Xanthomonas campestris (Pammel) Dowson produces pectic enzymes under the influence of different carbon sources. Polymethyl galacturonase (PMG) was a pectin-inducible enzyme in X. campestris , being best extruded with pectin as carbon source. Addition of glucose to pectin had practically no effect, to a smaller extent NaPP (sodium polypectate) effectuated PMG secretion. Addition of CMC to NaPP lowered the PMG secretion, glucose and maltose were found to be poor carbon sources for PMG induction. Polygalacturonase (PG), too, was adaptively produced in the culture filtrate of the pathogen, grown with NaPP as the carbon source. Addition of glucose to NaPP enhanced PG secretion and that of CMC retarded it. Glucose, pectin, and maltose individually caused PG liberation, but in a very minor way. 30 °C and 60 min of enzyme-substrate incubation were found to be optimum physical conditions for the secretion of PMG and PG. Polygalacturonase trans-eliminase (PGTE) was an exo-cellular enzyme, produced by X. campestris under adapted condition with NaPP as the best inducible carbon source. Separate addition of glucose and CMC to NaPP reduced PGTE extrusion. Pectin, glucose, and maltose separately effected PGTE liberation, but to a very limited extent, being much less than with NaPP. Addition of glucose to pectin suppressed whatever PGTE the pectin was alone able to produce.

Prospects for Ocean Thermal Energy Conversion (OTEC) in the Pacific: ABSTRACT

Ocean Thermal Energy Conversion (OTEC) may be the most promising future electrical energy source for many of the Pacific nations located between 20°N and 20°S latitudes. Within this band are found the optimum physical, economic, social, and cultural conditions for OTEC development. Several of the island nation governments in this region have declared OTEC to be the preferred alternative to their existing fossil fueled power plants, the fuel for which is imported at a severe economic penalty. In addition to OTEC serving as the cornerstone of energy self-sufficiency, these nations are also attracted to the potential OTEC by-products including fresh water, mariculture, and cooling water. Their interest is also stimulated by the potential for industrial expansion an economic development based on the added electrical baseload capacity OTEC can provide. Many multi-island nations see OTEC as a modest-sized decentralized energy facility that could serve remote population centers not serviceable from large central power stations. Many factors contribute to the prospects for OTEC development in the Pacific and there has been notable progress to date. Demonstration OTEC facilities have been built and tested in Hawaii and on Nauru. Designs, site surveys, and environmental assessments for commercial OTEC plants have been prepared for Guam, Tahiti, Okinawa, and Saipan. Planning for OTEC is underway in American Samoa, Palmyra, Yap, and the Marshall Islands. An ammonia-producing OTEC plantship has been proposed for grazing in the central Pacific. These projects illustrate the strong interest in OTEC development that is found throughout the central Pacific. End_of_Article - Last_Page 974------------

蚊類のデングウイルス感受性に関する研究 : II. ウイルス実験宿主としての Toxorhynchites amboinensis (Doleschall) の継代飼育法の改良

The purpose of this study was to examine methods of improving the mass rearing techniques of a non-biting mosquito Toxorhynchites amboinensis (Doleschall), which is an efficient laboratory host for dengue virus when the virus is injected intrathoracically. Experiments were directed at (1) the establishment of individual rearing techniques thus preventing larvae cannibalism; (2) the development of a suitable food for the larvae; and (3) the definition of the optimum physical conditions for larvae growth. 1. The larvae were reared individually in 3ml disposable trays containing 2ml of water or in 200ml plastic cups containing 50ml of water with Aedes albopictus (Skuse) larvae provided as food. The larval period at 27℃ was 18.1 days with a pupation rate of 89.1% in the disposable trays and 18.6 days and 94.1% in the plastic cups. In group rearing of 50 larvae in plastic trays (27×35×8cm) containing 3 liters of water, the larval period was 18.1 days and the pupation rate was 29.9%. It was shown that the individual method gives higher pupation rates and that the use of larger containers give slightly better results. 2. The larvae were reared using the following feed : Tetramine^[○!R], Vita-shrimp^[○!R], liver powder, dried water fleas, dried blood worms, and drone powder. The average larval periods were 47.7,45.5,56.0,53.7,43.7 and 52.0 days, respectively. The pupation rates were 70,70,50,80,40 and 10%, respectively. Larvae reared with a combination of a living diet of newly hatched brine shrimp Artemia salina (Linnaeus) for the young larval stage and the blood worm Limnodrilus hoffmeisteri Claparede for the third and fourth larval stages pupated after an average of 23.2 days at 25℃ with a pupation rate of 100%. These results were almost the same or slightly better than those obtained with group rearing by the conventional method providing Aedes albopictus larvae in which the larval period was 24.1 days and the pupation rate 90%. 3. The larvae were reared by providing a combined living diet at the temperature levels of 20,25,27 and 30℃. No larval growth was seen at 20℃, and the average preadult periods and pupation rates at the higher temperatures were 32.2,29.4 and 27.4 days, and 100,90 and 80%, respectively. At 30℃ the death rate of the blood worms was high enough to cause fouling of the water.

Spatial aspects of reproduction in buffalo sculpin,Enophrys hison

The spatial distribution and parental care of demersal egg masses of buffalo sculpin (Enophrys bison) were studied at 11 areas in Puget Sound, Washington, during 1972–1973. Adult buffalo sculpin inhabited rock and rock-sand habitats at depths from the intertidal to minus 20 m throughout the year, but 84% of all spawn clusters were found at depths between −1 m and +1 m within localized rocky areas. Areas used for spawning were exposed to strong tidal currents and other water movements. A single male fish guarded and fanned spawn, but eggs were temporarily deserted when less than about 1 m of water covered the spawning site. The cyclical nature of male desertion, behavior of spawn predators, and spawn mortality due to physical factors while emergent suggest several possible advantages to low intertidal spawning. These advantages include spatial and temporal escape from marine predators by embryos, time for the tending parent to forage, and optimal physical conditions for embryonic development.

Moisture permeation of newer unit dose repackaging materials

Moisture permeation of some unit dose repackaging materials currently available was tested and compared with the results of an earlier study. Seventeen unit dose containers marketed for hospital pharmacy repackaging were tested. Most of the samples were prepared in a laboratory under optimal physical and mechanical conditions. The methodology involved packaging a desiccant pellet, storage at 75 +/- 3% relative humidity and 20 +/- 2 C, and weighing at various time intervals. Each container was placed into one of four classes depending upon the amount of weight gain. In general, moisture permeation values for all types of materials were much lower than in the previous study. The results show that improved moisture protection can be achieved through modifications in typical repackaging systems.

EFFECTS OF HIGH TEMPERATURE AND VAPOR PRESSURE DEFICIT ON EUROPEAN PINE SHOOT MOTH, RHYACIONIA BUOLIANA (LEPIDOPTERA: OLETHREUTIDAE), EGG PRODUCTION AND SURVIVAL

AbstractFecundity and egg survival had inverse linear relationships with increasing evaporation potentials expressed as vapor pressure deficits. With an increase of vapor pressure deficit from 4 to 24 mm Mg at a favorable temperature of 25.5 °C, mean fecundity could be reduced from 130 to 51 eggs and egg survival from 90% to 20%. Optimal laboratory physical conditions for egg production consisted of a low evaporation rate of less than 9 mm Hg vapor pressure deficit but short of a saturated atmosphere at a room temperature of 25.5 °C. One hour daily exposure of eggs to high temperatures up to 39 °C did not cause a significant increase in egg mortality. In the field there was no difference in fecundity of females between plots in damp western Washington and dry central Oregon (pine region). Egg mortality was always higher at the central Oregon plot, presumably because of higher evaporation rates. Since high vapor pressure deficits are common occurrences during the growing season in most of the pine region, it is possible this factor could limit Rhyacionia buoliana populations in some of these areas.

I. Red Blood Cell Hemolysis by Photosensitizing Compounds

Irradiation (290–370 and 320–400 nm) of red blood cells in the presence of some photosensitizing compounds caused hemolysis. The extent of photohemolysis was determined to evaluate effects of these compounds on red blood cell membranes. Tested substances included porphyrins, tetracyclines, psoralens, salicylanilides, phenothiazines, anthracenes and sulfonamides. Optimal physical and chemical conditions for photohemolysis were determined for each compound. Amount of hemolysis varied with pH, solvent and buffer system and sensitizer. Strongly buffered solutions tend to inhibit the reaction. We interpret the reaction to be phototoxic, presumably to the cell membrane, because the RBC is essentially devoid to organelles and the reaction rate increased as the concentration of the photosensitizer increased. Non-photosensitizing substances did not react. Effect of the test compounds on RBCs were monitored with a spectrophotometer and fragiligraph, which indicated that some drugs combine with the RBC membrane in the dark and other require light. Psoralens and tetracyclines did not induce photohemolysis.

Optimum physical and chemical conditions for the Methylene Blue method of estimating gaseous sulphide in the environment

The sensitivity and reproducibility of the Methylene Blue method for gaseous sulphide estimation have been investigated with respect to physical conditions and the concentrations of the reagents, especially sulphuric add. A new design of absorber is proposed to minimize gas-phase loss of the sulphide in the final stage of the procedure.

Effects of Tillage Management on Soil Porosity and Bulk Density on Rape (Brasica Napus)

Soil tillage systems have a major influence on soil physical characteristics. Optimal soil physical conditions for crop rooting are a result of complex interactions between soil structure and oxygen and water supply to plants roots.
 The experiment has been conducted in the Didactic Station of the University of Agricultural Sciences and Veterinary Medicine of Iasi, Ezareni Farm. The purpose of this experiment was to investigate the influence of three soil tillage systems (a reduced tillage system, a no-tillage system and conventional tillage system) on several physical characteristics of the soil, such as soil bulk density, soil porosity and soil structural stability.

Nutrition as a factor influencing hypopus formation in the Acarus siro species complex (Acarina, Acaridae)

Three species of mites, Acarus siro L., A. farris Oud. and A. immobilis Griffiths, were tested under optimum physical conditions (90% r.h. and 20°C). In most experiments hypopus production was estimated by comparing the number of protonymphs which developed promptly to tritonymphs with the number which developed to hypopi. Hypopus formation appeared to be favoured by malnutrition in the presence of a certain minimum quantity of B vitamins. The period of response embraced the active larval and active protonymphal stage and the response appeared to be cumulative. It scemed to remain reversible through the larval stage but at some point during the active protonymphal period it became irreversible. The developmental period of those protonymphs which became hypopi was much extended compared with the developmental period of those which proceeded directly to tritonymphs. It is concluded that this extension is associated with physiological and developmental changes peculiar to the hypopus and not with starvation. Acarus immobilis and Acarus farris, which have been shown to be mainly field species, produced more hypopi than the storage species Acarus siro, one population of which could not be induced to produce any hypopi. It is concluded that previously published records of the “Flour mite” motile hypopus from field habitats are probably based on the A. farris hypopus and the records of the “Flour mite” motile hypopus occurring in food stores are scarce because the storage species A. siro has a poor potential for hypopus formation or rarely encounters starvation conditions. Misidentifications, coupled with interspecific differences in hypopus production, may explain some of the conflicting results published by previous workers testing the same physical factors.