There is a lot of interest in the studies that would help to understand whether there is a casual association between cancer and various types of molecular or cytogenetic damage detected in human cells. One major oncogenesis process is activation of proto-oncogenes by point mutations or chromosomal translocation. There are substantial evidence that indicates that the loss of heterozygosity of certain chromosomes is involved in human cancerogenesis. Our study aimed to elicit the possible association between cancer and DNA and cytogenetic abnormalities induced in lymphocytes of people bearing various categories of skin cancer cells. Fresh blood was collected by venipuncture from 25 individuals (including nine prior to cancer treatment). All patients were nonsmoking males, however 42.3 % of them were former smokers. Blood samples were divided into two parts and in the first part of samples cytogenetic ...
Cyteogenetic maps of sorghum chromosomes 3-7, 9, and 10 were constructed on the basis of the fluorescence in situ hybridization (FISH) of ~ ... regions of heterchromatin were delimited for all 10 sorghum chrom...
The results of an investigation into tailed nuclei (TN) and features of dose dependence on frequency of the binuclear cells with TN in human lymphocyte cultures by cytogenetic block method upon X-ray radiation dose are presented. The frequencies of metaphases with dicentric and ring chromosomes are investigated concurrent with TN formed upon completion of first postradiation mitosis. Frequency of the appearance of binuclear cells with nuclei having outgrowth into the cytoplasmic space and arises after first mitosis in human lymphocyte culture is linear-square dependent on the X-irradiation at doses from 0.0 to 4.0 Gy. Positive correlation between frequency of cells with tailed nuclei and frequency of metaphases of first mitosis having dicentric and rings was established. Apparently, formation such TN is connected with dicentric and rings
Ramsar, a city in the northern Iran, has the highest level of natural background radiation in the world. It has been clearly shown that low doses of ionising radiation can induce resistance to subsequent higher exposures. This phenomenon is termed radioadaptive response. We have compared induction of cytogenetic radioadaptive response by High Natural Background Radiation (HNBR) in Ramsar and X-ray occupational exposure as conditioning doses in human peripheral blood lymphocytes. 30 healthy control individuals, living in Ramsar but in normal background radiation areas, 15 healthy individuals from Talesh Mahalleh, a region with extraordinary high level of background radiation, and 7 X-ray radiographers working in Ramsar hospital located in normal natural background ionising radiation area were evaluated. Peripheral blood samples were prepared ...
Through an unusual differentiation process, human trophoblast progenitors (cytotrophoblasts) give rise to tumor-like cells that invade the uterus. By an unknown mechanism, invasive cytotrophoblasts exhibit permanent cell cycle withdrawal. Here we report molecularcytogenetic data showing that {approx} 20 to 60 percent of these interphase cells had acquired aneusomies involving chromosomes X, Y, o r16. The incidence positively correlated with gestational age and differentiation to an invasive phenotype. Scoring 12 chromosomes in flow-sorted cytotrophoblasts showed that more than 95 percent of the cells were hyperdiploid. Thus, aneuploidy appears to be an important component of normal placentation, perhaps limiting the proliferative and invasive potential of cytotrophoblasts within the uterus.
Despite their ecological and economical importance, fishes of the family Ariidae are still genetically and cytogenetically poorly studied. Among the 133 known species of ariids, only eight have been...Full Text Available
The cytogenetic findings were analysed in a series of 500 pregnancies in which chorionic villi sampling was performed. In all cases a direct method was used, karyotyping being successful in 481 cases...Full Text Available
It has recently been found that many buildings in Taiwan were constructed with radioactively contaminated rebar, which raised great concern among the residents as well as governmental officials. In order to investigate the possible cytogenetic damage to the residents of contaminated buildings, a G-banding method was carried out on the lymphocytes of 30 radiation-exposed individuals from four families and one office building, as well as 15 control individuals from laboratory personnel. The estimated cumulative radiation doses for the exposed people range from 19.63 to 280.50 mSv. Altogether, 13 females and 17 males belonging to the radiation-exposed group, and 7 females and 8 males in the control group, were included in this study. With the exception of one sample, at least 500 metaphase spreads were scored and analyzed for each individual. All the recognizable structural aberrations of chromosomes or ...
It has recently been found that many buildings in Taiwan were constructed with radioactively contaminated rebar, which raised great concern among the residents as well as governmental officials. In order to investigate the possible cytogenetic damage to the residents of contaminated buildings, a G-banding method was carried out on the lymphocytes of 30 radiation-exposed individuals from four families and one office building, as well as 15 control individuals from laboratory personnel. The estimated cumulative radiation doses for the exposed people range from 19.63 to 280.50 mSv. Altogether, 13 females and 17 males belonging to the radiation-exposed group, and 7 females and 8 males in the control group, were included in this study. With the exception of one sample, at least 500 metaphase spreads were scored and analyzed for each individual. All the recognizable structural aberrations of chromosomes or ...
We investigate the radiative decays of the {phi}-meson to the scalar mesons a{sub 0}(980) and f{sub 0}(980). We demonstrate that, contrary to earlier claims, these decays should be of the same order of magnitude for a molecular state and for a compact state and, therefore, the available experimental information is consistent with both a molecular as well as a compact structure of the scalars. Thus, the radiative decays of the {phi}-meson into scalars establish a sizable K anti K component of the scalar mesons, but do not allow to discriminate between molecules and compact states. (orig.)
A brief overview if provided of selected reports presented at the International Symposium on Molecular Mechanisms of Radiation- and Chemical Carcinogen-Induced Cell Transformation held at Mackinac Island, Michigan on September 19-23, 1993.
Flow cytogenetics is a rapidly developing technology which complements rather than supplants the traditional methods of cytogenetic analysis. As an adjunctive approach to chromosome classification, flow systems measurements of isolated chromosomes give new information relative to the enrichment of A-T or G-C base sequences on specific chromosomes. As a result, chromosomal fluorescence polymorphisms both within and among individuals that are not always associated with banding polymorphisms can be detected. Finally, flow sorting provides bulk quantities of highly purified chromosomes for use in biochemical studies. Methodology is detailed. (PSB)
In experiments designed to detect new mutations affecting hemoglobin, we irradiated the male or female parent in reciprocal crosses of two mouse strains that differ in alleles at the hemoglobin (Hba, Hbb) loci as well as at five other specific loci. Offspring were analyzed for hemoglobin properties (electrophoretic pattern, solubility, crystal pattern), serum albumin differences, erythrocyte lysis, reticulocyte count, and external appearance. Five hemoglobin variants were found among the mutants. In three, the genetic contribution from the irradiated father was not expressed with regard to the #alpha#-chain; one carried a tandem duplication (the first known case in the mouse) involving Hbb; and one probably resulted from double nondisjunction of chromosome 7. The finding that major chromosome aberratios can mimic hemoglobin mutations indicates the need, in similar experiments, to follow F_1 screening with thorough cytogenetic analysis. The variants in which there ...
Background:Frozen shoulder (FS) is a debilitating musculoskeletal condition with an uncertain etiology and pathogenic mechanism. The aim of this study was to investigate...Full Text Available
Some aspects of molecular mechanisms common to radiation and chemical carcinogenesis are discussed, particularly the DNA damage done by these agents. Emphasis is placed on epidemiological considerations and on dose-response models used in risk assessment to extrapolate from experimental data obtained at high doses to the effects from long-term, low-level exposures. 3 references, 6 figures. (ACR)
The following topics are discussed: insertion of incorrect bases in DNA; ability of DNA polymerase to copy uv-irradiated DNA; role of enzymes in repair of DNA; effects of uv radiation on molecular weight of DNA; photoreactivation; repair of DNA in Escherichia coli and xp cells following uv radiation; and synchrotron radiation studies on DNA repair. (HLW)
This review briefly describes current efforts to develop superradiant sources of coherent radiation for the sub-nanometer range of wavelenghs, using nuclear rather than the atomic or molecular transitions that are stimulated in existing lasers. First the radiative (including Raman) interactions of nuclei with those of atoms and molecules are compared; then the present status of research on the fundamental problems involved in stimulating nuclear gamma radiation is described. (author). 20 refs.; 2 figs.
A 36-year-old woman underwent amniocentesis for advanced maternal age. The fetal karyotype had an extra dark staining G band on the long arm of chromosome 11 with no other identifiable abnormalities. FISH studies using a chromosome 11 paint probe confirmed the origin of the extra band. The abnormality was identified as a partial duplication of 11q: 46,XX dir dup (11)(q13.5q21) or (q21q23.1). The specific duplicated band could not be identified with certainty. Detailed fetal sonograms were normal. Family studies revealed the identical duplication in the mother but normal karyotypes in both maternal grandparents. The mother had strabismus and a short tongue frenulum which required surgical correction. Menses occurred late in adolescence and complete development of secondary sexual characteristics was delayed until adulthood. An infertility evaluation revealed duplication of the uterus, cervix, and vagina. An evaluation for metorrhagia identified a pituitary adenoma which was resected. ...
The fauna of ancient lakes frequently contains taxa with highly derived morphologies that resulted from in situ radiation of lacustrine lineages with high antiquity. We employed a molecular...Full Text Available
Voxel-based prescriptions of deliberately non-uniform dose distributions based on molecular imaging, so-called dose painting or theragnostic radiation therapy, require specification of a transformation...Full Text Available
Abstract Routinely used prognostic factors fail to predict clinical outcome in a significant proportion of breast cancer patients, implying that they can not detect some important biological characteristics. Chromosomal changes have been described in breast carcinomas for many years but their significance is not clear. We compared chromosomal changes with clinico-pathological characteristics and clinical outcome in 203 breast cancer patients with a follow-up of 9-18 years. Combining data from classical cytogenetics and flow cytometry revealed chromosomal abnormalities in 142 cases (70%). Of these, 51 (35.9%) contained two or more cytogenetically abnormal clones. Polyclonality was significantly associated with poor breast-cancer-specific survival (P = 0.03) within 5 years, independent of tu...
In order to gain an overall picture of the genetic effects of an increased level of background radiation it is necessary to study the results of protracted exposures to embryonic and immature germ-cell stages as well as to stages found in the mature organism. For this purpose, litters produced by female mice, kept in a 10 or 20 rad/day /sup 60/Co ..gamma..-irradiation field, were kept in the same fields from conception until about 60 days later, having absorbed doses of 526 and 1078 rad respectively. Tests on exposed female offspring showed them to be sterile. Eight weeks after removal from the gamma field, mean testis masses of males in the 20 rad/day series were only half normal but those receiving 10 rad/day were little affected. Frequencies of translocations in spermatocytes at diakinesis/metaphase I were only slightly increased in the exposed series, differences not being significant. Estimated rates of translocation induction were around 5 x 10sup(-6) per ...
The interaction of thermal radiation with conduction and convection in thermally developing absorbing, emitting, nongray gas-particulate turbulent suspension flow through a circular tube is investigated. The contribution of thermal radiation is obtained through evaluation of the total hemispherical emittance of the particulate cloud and through evaluation of single band absorptances for molecular gases, modified to account for the interaction with the particles. The governing differential equation is derived as a (nonlinear) energy equation, coupled with integral equations to find the thermal radiation contributions. The energy equation is solved numerically by an implicit finite difference method with an iterative procedure. Qualitative results for Nusselt numbers are shown for a variety and range of parameters, such as optical thickness of particulates and single molecular gas ...
The interaction of thermal radiation with conduction and convection in thermally developing absorbing, emitting, non-gray gas particulate turbulent suspension flow through a circular tube is investigated. The contribution of thermal radiation is obtained through evaluation of the total hemispherical emittance of the particulate cloud and through evaluation of single band absorptances for molecular gases, modified to account for the interaction with the particles. The governing differential equation is derived as a (nonlinear) energy equation, coupled with integral equations to find the thermal radiation contributions. The energy equation is solved numerically by an implicit finite difference with its iterative procedure. Qualitative results for Nusselt numbers are shown for a variety and range of parameters, such as optical thickness of particulates and single molecular gas bands, ...
Abstract Localized regions of enhanced emission from HCO+, NH3 and other species near Herbig-Haro objects (HHOs) have been interpreted as arising in a photochemistry stimulated by the HHO radiation on high-density quiescent clumps in molecular clouds. Static models of this process have been successful in accounting for the variety of molecular species arising ahead of the jet; however, recent observations show that the enhanced molecular emission is widespread along the jet as well as ahead. Hence, a realistic model must take into account the movement of the radiation field past the clump. It was previously unclear as to whether the short interaction time between the clump and the HHO in a moving source model would allow molecules such as HCO+ to reach high enough levels, and to survive fo...
Schizophrenia and bipolar disorder are leading causes of morbidity across all populations, with heritability estimates of ∼80% indicating a substantial genetic component. Population genetics...Full Text Available
We report the case of a 22-year-old man with Ewing's sarcoma who attained a complete remission (CR) after combination radiotherapy and chemotherapy. Secondary acute lymphoblastic leukemia with multiple cytogenetic abnormalities involving chromosome 5 and 7 developed 16 years later. The patient underwent induction chemotherapy and entered a CR. Peripheral blood stem cell transplantation from a matched sibling was performed successfully and he is in complete remission of both ALL and Ewing's sarcoma. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)
Endothelial dysfunction is involved in radiation responses in many normal tissues, including intestine. Endothelium-directed interventions ameliorate intestinal radiation injury (radiation enteropathy) in animal models, and anecdotal reports also suggest a beneficial effect of heparin. This study assessed low molecular weight heparin as an intestinal radiation response modifier. Rats underwent localized small bowel irradiation. Groups of rats were treated with saline, nadroparin (3 mg/kg/d), or a non-anticoagulant heparin (SR80258, 3 mg/kg/d), from 3 days before to 2 weeks after irradiation. The intestinal radiation response was assessed 2 weeks and 6 weeks after irradiation using quantitative histology; morphometry, and cellular and molecular end-points. Compared to vehicle-treated controls, nadroparin significantly exacerbated structural ...
Radiation inactivation and sedimentation equilibrium analysis were used to determine the functional and physical size of the chicken hepatic membrane receptor that binds N-acetylglucosamine-terminated glycoproteins. Purified plasma membranes from chicken liver were irradiated with high energy electrons and assayed for 125I-agalactoorosomucoid binding. Increasing the dose of ionizing radiation resulted in a monoexponential decay in binding activity due to a progressive loss of binding sites. The molecular mass of the chicken lectin, determined in situ by target analysis, was 69,000 +/- 9,000 Da. When the same irradiated membranes were solubilized in Brij 58 and assayed, the binding protein exhibited a target size of 62,000 +/- 4,000 Da; in Triton X-100, the functional size of the receptor was 85,000 +/- 10,000 Da. Sedimentation equilibrium measurements of the purified binding protein yielded a lower limit ...
The point at which the common final pathway for induction of cancer by chemical carcinogens and ionizing radiation has not been identified. Although common molecular targets are suggested by recent findings about the role of oncogenes, the mechanism by which the deposition of radiation energy and the formation of adducts or other DNA lesions induced by chemicals affects the changes in the relevant targets may be quite different. The damage to DNA that plays no part in the transformation events, but that influences the stability of the genome, and therefore, the probability of subsequent changes that influence tumorigenesis may be more readily induced by some agents than others. Similarly, the degree of cytotoxic effects that disrupt tissue integrity and increase the probability of expression of initiated cells may be dependent on the type of carcinogen. Also, evidence was presented that repair of the initial lesions could ...
A study of the influence of the concentration of secondary addition, high concentrations of primary dopant, diffusion enhancer and stabilizer on radiation hardness is presented. It is concluded that the diffusion enhancing technique is the most powerful method for improving radiation hardness. A new polystyrene scintillator which contains 2% pT, 0.02% POPOP, 20% diffusion enhancer and 0.02% stabilizer gave 91% of initial light output immediately after 3 Mrad irradiation in air. Data are presented that show that scintillator prepared from commercial polymer is more radiation-hard and has greater light output than scintillator prepared from monomer. It is assumed that this difference is due to different molecular weight distributions. Some protocols for acceleration of aging (yellowing and crazing) are presented. It is shown that one of the main reasons for aging of plastic scintillators is residual ...
Repetitive hydatidiform mole was observed in four pregnancies. The pregnancies presented with heavy bleeding and vomiting, but the post-evacuation courses were uncomplicated, with rapid regression of serum hCG levels. Cytogenetic investigations, analyses of restriction fragment length polymorphisms, and flow cytometry in three pregnancies were consistent with diploid, biparental conception as the origin of fetal tissue and molar and nonmolar villi. In one pregnancy, the analyses of cytogenetic markers suggested the coexistence of two different cell lines of dizygotic, biparental origin, whereas DNA analysis was consistent with a single conception. With incomplete genetic information, a hydatidiform mole with coexistent normal fetus is generally considered to result from dizygous twinning comprising an androgenetic complete mole and a normal conception. In the present gestations, the results based on several techniques applied on numerous ...
We have performed molecular dynamics simulations of radiation damage in fused silica. In this study, we discuss the role of successive cascade overlap on the saturation and self-healing of oxygen vacancy defects in the amorphous fused silica network. Furthermore, we present findings on the topological changes in fused silica due to repeated energetic recoil atoms. These topological network modifications consistent with experimental Raman spectroscopic observation on neutron and ion irradiated fused silica are indicators of permanent densification that has also been observed experimentally.
One of the greatest opportunities for using of biomass as a precursor in the production of polymeric materials is the lignocellulose composites that can combine high performance with low costs. This work is a initial study on the production of a lignocellulose reinforced polyethylene composite. A compatibilization made by a induced gamma radiation grafting reaction was used to increase the adhesion between the matrix and the reinforced or filled fibers. The lignocellulose materials were exposed to gamma radiation in order to promote a molecular degradation and increase its reactivity. The polymer, the lignocellulose material and the compatibilization were processed by extrusion and the composite produced by this process were characterized by mechanical tests. (author)
Polytetrafluoroethylene was obtained by radiation induced polymerization of tetrafluoroethylene in acetone at 195 K. An average diameter of the products was very small compared with commercial one; it was about 0.3 micro-meters. The yield was reached to 100% with a dose of 4 kGy. The crystallinity of the products is decreasing with increasing dose. The products become amorphous, for higher irradiation doses. It was found that PTFE obtained by irradiation of TFE in acetone at 195 K has branching structure. This was demonstrated by means of "1"9F MAS NMR. (Author)
Research performed at LAMPF during 1985 is reported in the areas of: nuclear and particle physics; atomic and molecular physics; materials science; radiation-effects studies; biomedical research and instrumentation; nuclear chemistry; radioisotope production; and physics theory. Also reported are the status of LAMPF-II, facility development work, and accelerator operations. (LEW)
Conceptual and factual advances in understanding neuronal migration in the past two decades have provided new insight into the pathogenesis of brain malformations at the cellular, molecular, and functional levels. Some of these results may have direct implications in understanding the consequences of ionizing radiation on the fetal central nervous system in utero. (orig.).
Epidemiological studies will not solve the shape of the dose effect curve for stochastic effects in the low dose range. Unicellular processes are necessary for the primary processes so that no threshold dose exists. This is evident for somatic and genetic mutations. Not clearly solved is this question for the complex carcinogenesis. These processes develop with manifold interacting molecular and cellular steps. (orig.).
Solar ultraviolet radiation is damaging for living organisms due to its high energy pro each photon. The UV radiation is often separated into three regions according to the wavelength: UVC (200-280 nm), UVB (280-320 nm) and UVA (320-400 nm). The most hazardous part, UVC is absorbed completely in the upper atmosphere by molecular oxygen. UVB radiation is absorbed by atmospheric ozone partly, and it is reaching Earth`s surface, as UVA radiation. Besides atmospheric ozone, very important factors in determining the intensity of UVB radiation globally are the solar zenith angle and cloudiness. It may be calculated from global ozone changes that the clear-sky UVB doses may have enhanced by 10-15 % during spring and 5-10 % during summer at the latitudes of Finland, following the decrease of total ozone between 1979-90. The Finnish ozone and UV monitoring activities ...
Poly(methyl methacrylate), PMMA, Acrigel, a Brazilian polymer, is used in the manufacture of medical supplies sterelizable by ionizing radiation. However, when PMMA is gamma-irradiated it undergoes main chain scissions, which promote molecular degradation causing reduction in its mechanical properties. Therefore, radiolytic of PMMA is important for it to become commercially radiosterizable. In this work some commercial additives, originally used in photo-and thermo-oxidate stabilization of polymers, were tested. Only two additives, type HALS (Hindered Amine Light Stabilizer), denoted Scavenger, showed a good protective quality. The investigation of radiation-induced main scissions was carried out by viscosimetric method. The most effective additive, added to the polymer system at 0.3 w/w%, promotes a great molecular radioprotection of 93%. That means a reduction of G-value (scissions/100 eV) from 0.611 ...
In May 1990 a group of scientists representing several federal agencies, the International Society of Regulatory Toxicology and Pharmacology, the private sector, and academia met to develop a strategy to encourage the study of the biological effects of low level exposures (BELLE) to chemical agents and radioactivity. A workshop was held in 1991 with seven invited speakers focusing on the toxicological implications of biological adaptations. The selection of topics and speakers was designed to consider critically the concept of hormesis, not only in a broad, conceptual manner, but also at the molecular and biochemical levels. These presentations offered a complementary perspective on the diverse range of molecular mechanisms that can become activated at low levels of toxicant exposure. In addition to chemical toxicology research, an overview of current research on 'Effects of low-dose radiation on the immune response' was ...
The possible genetic (dominant lethal mutations (DLM) and cytogenetic changes in the regenerating liver) and somatic (hematopoietic stem cell changes, growth and nonspecific life time shortening) effects in mice maintained on tritiated water (HTO) over two generations was investigated. Results to date are summarized. (ACR)
The authors present the results of an investigation of the effect of gamma radiation on the properties of low-molecular moulded polymethyl methacrylates (molecular weight distribution, physico-mechanical properties, resistance to the effects of aqueous media and physiological solution) in the form of copolymers of methyl methacrylate with methyl acrylate (MA) or butyl acrylate (BA) with the brand names Dacryl-4B, Dacryl-2M and Dacryl-4M (4% BA; 2 and 4% MA respectively) having a molecular weight of around 10"5. For comparison, block polymethyl methacrylate with a molecular weight of 3 x 10"6 was used. The results of experiments on the ageing of unirradiated and irradiated specimens in a heated store-room (t = 10 - 20"0C) and at high temperatures (90"0C) are also given. It is shown that irradiation with doses of 2.5 - 20 Mrad leads to radiolysis of the above copolymers, accompanied ...
The authors present the results of an investigation of the effect of gamma radiation on the properties of low-molecular moulded polymethyl methacrylates (molecular weight distribution, physicomechanical properties, resistance to the effects of aqueous media and physiological solution) in the form of copolymers of methyl methacrylate with methyl (MA) or butyl acrylate (BA) with the brand names Dacryl-4B, Dacryl-2M and Dacryl-4M (4% BA; 2 and 4% MA respectively) having a molecular weight of around 10"5. For comparison, block polymethyl methacrylate with a molecular weight of 3 x 10"6 was used. The results of experiments on the ageing of unirradiated and irradiated specimens in a heated store-room (t = 10 - 20"0C) and at high temperatures (90"0C) are also given. It is shown that irradiation with doses of 2.5-20 Mrad leads to radiolysis of the above copolymers, accompanied by ...
Comprehensive investigation has been made into the application of the polymerization hardening by radiation, particularly electron beam, to the composites of polymers and other materials. The report is divided into four parts, namely 1) characteristics and problems of the reaction of curing by radiation polymerization, 2) improvement of the bonding capability of high molecular weight materials, 3) bonding by radiation, and 4) composites made by the impregnation and polymerization hardening of monomers. The first part includes the effects of dose rate, temperature rise during the hardening, the peculiarity of electron beam irradiation at high dose rate, reaction environment and additive effects. Main conclusions are as follows: caution must be taken to the amount of residual double bonds because they affect the quality of hardened polymers; the polymerization hardening reaction at high dose rate cannot ...
The process of mouse skin tumor formation is subdivided into three operational stages. These stages include initiation, promotion and progression. Ionizing radiation has been found to be a weak initiating agent in the production of malignant squamous cell carcinomas, a complete carcinogen and an agent effective in causing tumor progression. Four skin tumor histologies have been seen with ionizing radiation: benign papillomas, squamous (SCC) and basal (BCC) cell carcinomas and fibrosarcomas. Distinct non-ras transforming genes have been detected in radiation initiated SCCs. A benign papilloma cell line (308) was used as a model system to study ionizing radiation induced progression. A variant 308 cell line (308 10 Gy 5) derived by irradiation of the parental 308 cell has been characterized. The 308 10 Gy 5 cells unlike the parental 308 cells from malignant tumors in athymic nude mice upon subcutaneous ...
Original investigations of ablation of minerals, fullerene-like compounds, polymers and complicated biological macromolecules under the action of submillimeter radiation of the free-electron laser (FEL) developed and built at Budker Institute of Nuclear Physics [V.P. Bolotin et al., First experiments on high-power Novosibirsk terahertz free-electron laser, Budker INP, 2005, p. 37 [1
Recent developments in the analysis of Mira atmosphere, the determination of the pulsation mode, the problem of mass loss, and the evolution of the Mira variables are covered. Model atmospheres for Mira variables, including the opacities of the molecules expected in very late M-type atmospheres are discussed. The pulsation constant for Omicron Ceti is evaluated using T(eff) = 2900 + or - 200 K, and it is concluded that Miras are fundamental mode pulsators. The importance of molecular opacity to the driving of mass loss is evaluated, and it is pointed out that the radiation pressure on molecules is not a major factor in driving mass loss from Mira. Mass loss is considered as a factor in the calculations of the periods for Mira variables. 30 refs.
In this article, we present our consistent efforts to explore the dynamical pathways of the migration of electronic radiation by using ultrafast (picosecond/femtosecond time scales) F?rster resonance energy transfer (FRET) technique. The ultrafast non-radiative energy migration from an intrinsic donor fluorophore (Tryptophan, Trp214) present in domain IIA of a transporter protein human serum albumin (HSA) to various non-covalently/covalently attached organic/inorganic chromophores including photoporphyrin IX (PPIX), polyoxovanadate [V15As6O42(H2O)]-6 clusters (denoted as V15) and CdS quantum dots (QDs) has been explored. We have also used other covalently/non-covalently attached extrinsic fluorogenic donors (NPA, ANS) in order to exploit the dynamics of resonance energy migration of an enz...
An effect of laser-cooling of water was observed for the first time with a temperature decrease dT = -2.2 K after irradiation of liquid water surface by a powerful Ar-Xe pulse laser with a pulse energy of about 1 J and wavelength L = 1.73, 2.63 and 2.65 um. The discovered effect can apparently be ascribed to the optical excitation of vibrational states of H2O molecules followed by an endothermic consolidation of chemically active excited molecules into a quasi-stable cluster-like structure. The measured time dependences of the cooling effect show that a typical life time of the new state of water amounts to hours. It has also been shown that the life time of the excited vibrational molecular states due to a radiation trapping effect can be estimated to at least hundreds of seconds.
Abstract We use Smoothed Particle Hydrodynamics to simulate the formation of a massive (106-M-) stellar cluster system formed from the gravitational collapse of a turbulent molecular cloud. We investigate the hierarchical clustering properties of our model system and we study the influence of the photoionizing radiation produced by the system's multiple O-type stars on the evolution of the protocluster. We find that dense gas near the ionizing sources prevents the radiation from eroding the filaments in which most of the star formation occurs and that instead, ionized gas fills pre-existing voids and bubbles originally created by the turbulent velocity field.
We describe a new apparatus that combines pulsed laser excitation in a molecular beam with surface-science methods for preparation of clean single-crystal surfaces and detection of adsorbates to enable state-selected studies of gas-surface reaction dynamics. Reactant molecules are prepared in specific vibrationally excited states via overtone pumping using tunable, narrow-band laser radiation. The collision-free environment of the molecular beam prevents relaxation of the prepared molecules before impact on the target surface and enables complete control over the collision energy and incidence angle. Chemisorption products are detected after a given deposition time by Auger electron spectroscopy. To achieve sufficient beam flux of state-selected reactant molecules for product detection by standard surface-science techniques, we use a high-intensity, short-pulse molecular-beam source matched to the low ...
Measuring gene expression using microarrays is relevant to many areas of biology and medicine, such as follow up of developmental stages and diseases onset, and treatment study. Since there can be tens of thousands of distinct probes on an array, each micro array experiment can accomplish the equivalent number of genetic tests in parallel. Arrays have therefore dramatically accelerated many types of investigations. For example, microarrays can be used to identify stress response genes by comparing gene expression in challenged versus normal cells. In the Molecular and Cellular Biology lab (MCB), the micro array experiments are performed within the Genomic Platform, fully equipped to analyse either the behaviour of bacteria during long space flight, the effect of low dose ionising radiation on the developing organism in mice, or the human individual radiation sensitivity. For the low dose effect, two main stages of ...
It is anticipated that early in the next century manned missions into outer space will occur, with a mission to Mars scheduled between 2015 and 2020. However, before such missions can be undertaken, a realistic estimation of the potential risks to the flight crews is required. One of the uncertainties remaining in this risk estimation is that posed by the effects of exposure to the radiation environment of outer space. Although the composition of this environment is fairly well understood, the biological effects arising from exposure to it are not. The reasons for this are three-fold: (1) A small but highly significant component of the radiation spectrum in outer space consists of highly charged, high energy (HZE) particles which are not routinely experienced on earth, and for which there are insufficient data on biological effects; (2) Most studies on the biological effects of radiation to date have been high-dose, high ...
Full text: In the upper layers of the Earth's atmosphere, molecular nitrogen absorbs the extreme ultraviolet (XUV) solar radiation. The absorption is associated with dipole-allowed excitation of states of singlet ungerade symmetry ("1#SIGMA#"+_u and "1#PI#_u), which are known to undergo predissociation due to coupling with a mainfold of "1#PI#_u states. We determined new N_2 isotopic lifetimes of many "1#SIGMA#"+_u and "1#PI#_u states via line broadening measurements in the frequency domain. Ultrahigh resolution XUV + UV ionization spectra were recorded (bandwidth #approx# 250 MHz, resolving power 10"7), from which the natural linewidth, i.e. lifetime, was determined. These lifetimes provide new information about the predissociation of the singlet ungerade states in N_2. Tunable narrowband XUV radiation was produced by successively pulsed amplification of cw dye laser radiation, frequency doubling the ...
A brief comparative review of possible mercury free fluorescent lighting technologies is presented, including rare-gas positive column discharges, molecular discharges, and dielectric barrier discharges. Detailed experimental results on xenon positive column discharges will then be considered. In order to judge whether xenon-based discharges are a viable UV source it is necessary to measure the radiant emittance (power per unit area) for the vacuum ultraviolet (VUV) resonance xenon emission at 147 nm. Two techniques to determine the VUV radiant emittance have been developed and applied to xenon discharges. One method combines the measured resonance level density using absorption spectroscopy and a calculation of the trapped decay rate for the resonance radiation to arrive at the radiant emittance at 147 nm. A second method utilizes a direct measurement of the radiance (power per unit area per unit solid angle) at 147 nm using a calibrated VUV ...
The survivability of the final optic, which must sit in the line of sight of high-energy neutrons and gamma rays, is a key issue for any laser-driven inertial fusion energy (IFE) concept. Previous work has concentrated on the use of reflective optics. Here, we introduce and analyze the use of a transmissive final optic for the IFE application. Our experimental work has been conducted at a range of doses and dose rates, including those comparable to the conditions at the IFE final optic. The experimental work, in conjunction with detailed analysis, suggests that a thin, fused silica Fresnel lens may be an attractive option when used at a wavelength of 351 nm. Our measurements and molecular dynamics simulations provide convincing evidence that the radiation damage, which leads to optical absorption, not only saturates but that a 'radiation annealing' effect is observed. A system-level description is provided, including ...
In situ assembly states of rat adipocyte glucose transport protein in plasma membrane (PM) and in microsomal pool (MM) were assessed by measuring target size (TS) of D glucose-sensitive, cytochalasin B binding activity. High energy radiation inactivated the binding in both PM and MM by reducing the total capacity of the binding (B/sub T/) without affecting the dissociation constant (K/sub D/). The reduction in B/sub T/ as a function of radiation dose was analyzed based on classical target theory, from which TS was calculated. TS in the PM of insulin-treated adipocytes was 58 KDa. TS in the MM of noninsulin-treated and insulin-treated adipocytes were 112 and 109 KDa, respectively. With MM, however, inactivation data showed anomalously low radiation sensitivities at low radiation doses showing a shoulder in the semilog plots, which may be due to an interaction with a radiation ...
Genetics, Genomics, and Molecular Biology USGS scientists develop and integrate new genetic and molecular techniques into systematic analyses to describe individuals and populations of fish .....
Poly(methyl methacrylate), PMMA, Acrigel, a Brazilian polymer, is used in the manufacture of medical supplies sterilisable by ionizing radiation. However, when PMMA is gamma-irradiated it undergoes main chain scissions, which promote molecular degradation causing reduction in its physical properties. Therefore, radiolytic stabilization of PMMA is important for to become it commercially radio sterilisable. In this work we investigated the radiolytic stabilization of PMMA by using HALS (Hindered Amine Light Stabilizer) additive, commercially used for photo and thermo oxidative stabilization of polymers. The investigation of the radiation-induced main chain scissions was carried out by viscometric method. The additive added to the polymer system at 0.3 % w/w promotes a molecular radioprotection of 61%. That means a reduction of G value (scissions/100 eV) from 2.6 to 1.0. In addition, the glassy transition ...
Little clinical evidence has been provided to show the minimization of radiation resistance of tumors using high linear energy transfer radiation. We therefore investigated the radiobiological and molecular pathological aspects of carbon beam therapy. A total of 27 patients with squamous cell carcinoma (SCC) of the cervix were treated using a carbon beam and 50 control patients with SCC of the cervix using a photon beam. The expression of Ki-67, p53, and p27 proteins before radiotherapy and 5 and 15 days after therapy initiation were investigated using immunohistochemistry. Similar changes were observed in Ki-67 labeling index (LI) and p53 LI during carbon and photon beam therapies. However, for carbon beam therapy, the mean p27 LI significantly decreased from 25.2% before treatment to 18.6% on the 5th day after treatment initiation, followed by a significant increase to 36.1% on the 15th day. In contrast, for photon beam ...
Thyroid cancer is the most frequently diagnosed endocrine cancer and causes more deaths than all other endocrine cancers combined. Research findings support the concept that a subpopulation of thyroid cancer cells displays properties characteristic of stem cells. These putative cancer-forming entities drive tumorigenesis as a result of their dual ability to undergo self-renewal and to differentiate into various types of cancer cells; they also mediate metastasis and are resistant to the effects of chemotherapy and radiation therapy. This Review discusses the cellular origin of thyroid cancer and the properties of the thyroid cancer stem cell niche. The article critically evaluates the methods used to identify molecular markers expressed by thyroid-cancer-initiating cells and outlines prosp...
The present article will review recent advances in focused ion beam (FIB) technology. With increasing demands for scale of integration, microfabrication technology is becoming more important and various new microfabrication tools and processing techniques are desired. FIB is one of the promising tools for future microfabrication technology. This provides maskless patterning capability, which is of importance for process simplification, nanofabrication and in the development of in situ vacuum processing. In situ vacuum processing systems are being developed by combining FIB and a molecular beam epitaxy system. Radiation damage may limit applications of FIB. However, it was demonstrated that low energy FIB (<1 keV) with very high brightness was reached and promising results for low damage processing have been obtained. (orig.).
The authors summarize the significant dose-related effects on brain development which have emerged largely within the last six years of study of prenatally exposed A-bomb survivors. The results are described primarily in terms of the DS86 estimates and differences between these and the older T65DR dose estimates are discussed. The severe mental retardation sample was based on 1598 individuals taken from the PE-86 sample, and the intelligence test scores considered from the same sample involved 1673 children. The authors also discuss some of the recent neurobiological developments that appear relevant to an understanding of the biological bases of dose-related events observed, and suggest future research that may contribute either to further delineation of exposure consequences or to the explanation of the cellular and molecular origins of observed effects. (UK).
uv irradiation (365 nm) of air-saturated methanol solutions of 20 drugs absorbing in the 300 to 400 nm region gave rise to oxygen uptake, as determined with a polarographic oxygen electrode. The drugs were tested for photosensitizing capability by either a Type I (free radical) or a Type II (single molecular oxygen) mechanism. This testing was done by the inclusion of either acrylamide or 2,5-dimethylfuran in the irradiated drug solution, with observation of the subsequent polymerization or oxidation, respectively. Phenothiazine and thiazide derivatives appear capable of photosensitization by both mechanisms; promethazine, trifluoperazine, and furosemide show relatively high reactivity. Diazepam (weak), hexachlorophene, aminacrine, pyrilamine, tetracycline, demeclocyline, quinine, and anthracene (strong) react only by a Type II mechanism, with a photosensitizing efficiency increasing in the order given. A correlation appears to exist with reports of in vivo ...
The degradation of irradiated human insulin in aqueous solutions was investigated in order to protect the protein against ionizing radiation. The influence of the drug concentration, excipients and irradiation temperature were studied.Aqueous solutions at pH 2 were irradiated by gamma rays or by accelerated electrons. Two different high-performance liquid chromatography (HPLC) methods were used: reverse-phase high-performance liquid chromatography (RP-HPLC)/UV and size exclusion liquid chromatography (SEC/UV) to investigate both the fragmentation and the formation of higher molecular weight proteins.In solution without excipients irradiated at ambient temperature at 10kGy, the loss of human insulin is almost complete. Addition of radio-protecting excipients (free radicals scavengers) and c...
Absorption coefficient data are presented for molecular oxygen at temperatures between 1100 and 2000K and discrete wavelengths between 211 and 235nm. Measurements were made behind reflected shock waves using broad-linewidth ultraviolet laser radiation generated from a frequency-quadrupled, tunable, pulsed Ti:Sapphire laser. Test mixtures consisting of 15% O"2, 15% He and balance Ar were used to minimize the influence of vibrational relaxation on the reflected shock temperature. The experimental results are in good agreement with theoretical calculations and confirm that discrete features from the Schumann-Runge system dominate between 211 and 235nm at temperatures higher than 1100K.
Radiation sterilization has several merits that it is a positively effective sterilization method, it can be used to sterilize low heat-resistant containers and high gas barrier films, and there is no possibility of residual chemicals being left in the packages. It has been commercially used in 'Bag in a Box' and some food containers. The #gamma# ray and an electron beam are commonly used in radiation sterilization. The #gamma# ray can sterilize large size containers and containers with complex shapes or sealed containers due to its strong transmission capability. However, since the equipment tends to be large and expensive, it is generally used in off production lines. On the other hand, it is possible to install and electron beam system on food production lines since the food can be processed in a short time due to its high beam coefficient and its ease of maintenance, even though an electron beam has limited usage such as sterilizing ...
A computer model of cryogenic system for storing solid antimatter is used to explore the radiative cooling-power requirements for long-term antimatter storage. If vacuum-chamber pressures as low as 10 to -18th power torr can be reached, and the rest of the large set of assumptions is valid, milligram quantities of solid antimatter could be stored indefinitely at 1.5 K using cooling powers of less than a microwatt. Many of the assumptions made are problematic and need verification, as they could potentially change the results greatly. The system modeled is a sphere of solid anti-parahydrogen at 1.5 K or below levitated in a spherical cryogenic vacuum chamber. The free matter gas in the chamber is assumed to be molecular hydrogen, and sublimation of both matter and antimatter is assumed to be negligible. The antihydrogen is assumed to be in thermal equilibrium, although annihilation-energy deposition is localized and hydrogen's ...
In order to investigate the effect of humidity on laminar burning velocity(S), the effect of humidity on the combustion reaction and radiation intensity was studied, taking account of dilution gases such as CO/sub 2/ and Ar which has the approximately identical characteristics to exhaust gas circulation(EGR) gas used to prevent NOx discharge from engines. According to the heat reaction theory, mean specific heat(C) of mixture, mean molecular weight(M) and adiabatic flame temperature(T) etc. were said to affect S but from experimental results, the effect of M and C could be ignored, compared with the effect of T. The relationship between S and H/sub 2/O, Ar of CO/sub 2/% in mixture of diluted gases was clarified. The effect of H/sub 2/O on S was mainly caused by changes of T. The effect of radical C/sub 2/, CH and OH on radiation intensity was similar to that of H/sub 2/O and Ar and the effect of H/sub 2/O on combustion was ...
The gene encoding the human type I pituitary adenylate cyclase activating polypeptide receptor (ADCYAP1R1) was mapped to chromosome 7 by PCR analysis of genomic DNA from a human/rodent somatic cell hybrid mapping panel. This assignment was confirmed and the gene localized to chromosome band 7p14 by fluorescence in situ hybridization. A yeast artificial chromosome containing ADCYAP1R1 was identified in the CEPH {open_quotes}B{close_quotes} Mega-YAC library. This YAC includes two highly polymorphic dinucleotide repeat sequences that will facilitate genetic studies of the contribution of ADCYAP1R1 in disease states of the central nervous and neuroendocrine systems. 13 refs., 1 fig.
Purpose/Objective: The role of programmed cell death (apoptosis) as a cellular response to cancer therapy such as radiation or chemotherapy is the subject of much study, and manipulation of the apoptotic response in tumor cells may be valuable in the treatment of a variety of cancers. Both p53 dependent and independent apoptotic pathways have been identified; p53 is mutated in at least 50 % of human cancers and a majority of radiation resistant tumors contain p53 mutations. This study is designed to examine the induction of programmed cell death in a human colon carcinoma cell line that possesses two mutated p53 alleles. Ionizing radiation alone, or in combination with the chemotherapeutic drug 5-fluorouracil (5-FU), were used to elicit the apoptotic response. This study will focus on whether these treatments can induce a significant apoptotic response in cells that have mutated p53 alleles. Materials and Methods: HT-29 ...
Background: EGFR (epidermal growth factor receptor) and VEGF (vascular endothelial growth factor) inhibitors confer clinical benefit in metastatic colorectal cancer when combined with chemotherapy. An emerging strategy to improve outcomes in rectal cancer is to integrate biologically active, targeted agents as triple therapy into chemoradiation protocols. Material and methods: cetuximab and bevacizumab have now been incorporated into phase I-II studies of preoperative chemoradiation therapy (CRT) for rectal cancer. The rationale of these combinations, early efficacy and toxicity data, and possible molecular predictors for tumor response are reviewed. Computerized bibliographic searches of Pubmed were supplemented with hand searches of reference lists and abstracts of ASCO and ASTRO meetings. Results: the combination of cetuximab and CRT can be safely applied without dose compromises of the respective treatment components. Disappointingly low rates of pathologic ...
Background: We consider cells as biological systems that process information by means of molecular codes. Many studies analyze cellular information processing exclusively in syntactic terms (e.g., by measuring Shannon entropy of sets of macromolecules), and abstract completely from semantic aspects that are related to the meaning of molecular information. Methods: This mini-review focusses on semantic aspects of molecular information, particularly on codes that organize the semantic dimension of molecular information. First, a general conceptual framework for describing molecular information is proposed. Second, some examples of molecular codes are presented. Third, a mathematical approach that makes the identification of molecular codes in reaction networks possible, is developed. Results...
Hyaluronic acid (HA) is a significant component of the extracellular matrix (ECM), particular interest being shown herein in synovial fluid. The present study aims to investigate the degrading effects of X-ray radiation on HA at radiotherapy doses. Measurements of viscosity and shear stresses on HA solutions have been made at different shear rates using various types of viscometer for different concentrations in the range 0.01-1% w/v of HA. The HA has been subjected to doses of 6 MV photon radiation ranging from 0 to 20 Gy, the major emphasis being on doses below 5 Gy. It is found that there is a dose-dependent relationship between viscosity and shear rate, viscosity reducing with radiation dose, this being related to polymer scissions via the action of radiation-induced free radicals. The dependency appears to become weaker at higher concentrations, possibly due to the contribution to viscosity from ...
This is the 1st revision of the INIS/ETDE Joint Thesaurus. It contains 20 953 valid descriptors and 8 600 forbidden terms. It was last updated in December 2003. The Joint Thesaurus contains the controlled terminology for indexing all information within the subject scope of both INIS (International Nuclear Information System) and ETDE (Energy Technology Data Exchange) information systems. The terminology is intended for use in subject description for input or retrieval of information in those systems. The thesaurus is a terminological control device used in translating from the natural language of documents, indexers or users into a more constrained system language It is also a controlled and dynamic vocabulary of semantically and generically related terms which covers a specific domain of knowledge. The domain of knowledge covered by this Thesaurus includes physics (in particular, plasma physics, atomic and molecular physics, and especially nuclear and high-energy ...
A Task Group of the International Commission on Radiological Protection (ICRP) has finished a report Biological Effects after Prenatal Irradiation (Embryo and Fetus) which has been approved by the Main Commission and Will be Published. Some new important scientific data shall be discussed in this contribution. During the preimplantation period lethality of the mammalian embryo is the dominating radiation effect. However, in mouse strains with genetic predispositions it has been shown that also malformations can be caused. This effect is genetically determined and its mechanisms is different from the induction of malformations during major organogenesis. Radiation exposures during this prenatal period leads ato an increase of genomic instability of cells in the normal appearing fetuses. These radiation effects can be transmitted to the next generation. A renewed analysis of individuals with severe mental retardation after ...
The progress of laboratory studies on the removal of NO/sub x/ and SO/sub 2/ with zeolite molecular sieves is reported. The trademark of these zeolite molecular sieves is Zeolon. (LK)
Accumulation of molecular damage and increased molecular heterogeneity are hallmarks of cellular aging. Mild stress-induced hormesis can be an effective way for reducing the accumulation of molecular...Full Text Available
Functionalizing of single molecules on surfaces has manifested great potential for bottom-up construction of complex devices on a molecular scale. We discuss the growth mechanism for the initial layers...Full Text Available
This paper explores for the first time the post-radiation-induced-graft polymerization on solid substrate using reversible addition-fragmentation transfer (RAFT) mechanism. Radiation-induced graft polymerization onto polymers is a potentially interesting technique to create easily new materials from highly resistant polymers, e.g. surface graft polymerization of acrylic acid (AA) onto poly(vinylidene difluoride) (PVDF) improves its surface properties without losing its excellent mechanical properties. As a consequence of the radical nature of the polymerization processes it is difficult to control molecular weight of grafted chains, and therefore design and standardize the properties of the final product. RAFT polymerization is a suitable method to obtain monodisperse polymers. The ability of the RAFT agents to control the polymer chain length could be an interesting approach to improve the grafted polymers obtained by ...
Full text: DNA rearrangement events leading to chromosomal aberrations are central to ionizing radiation-induced cell death. Although DNA double-strand breaks are probably the lesion that initiates formation of chromosomal aberrations, little is understood about the molecular mechanisms that generate and modulate DNA rearrangement. Examination of the sequences that flank sites of DNA rearrangement may provide information regarding the processes and enzymes involved in rearrangement events. Accordingly, we developed a method using inverse PCR that allows the detection and sequencing of putative radiation-induced DNA rearrangements in defined regions of the human genome. The method can detect single copies of a rearrangement event that has occurred in a particular region of the genome and, therefore, DNA rearrangement detection does not require survival and continued multiplication of the affected cell. Ionizing ...
Woolfolk, C. A. (University of Washington, Seattle). Reduction of inorganic compounds with molecular hydrogen by Micrococcus lactilyticus. II. Stoichiometry with inorganic...Full Text Available
NSF-NIST Interaction in Chemistry, Materials Research, Molecular Biosciences, Bioengineering, and ... Laboratory (CSTL). Materials research is centralized in the Materials Science and Engineering ...
With the improvements accomplished during the past 15 years in detection techniques and instrumentation and with the opening of space exploration, molecular spectroscopy has become a very efficient way to probe planetary atmospheres.
The Molecular Genetics and Carcinogenesis Section conducts studies using human epithelial cells to assess: activation of proto-oncogenes by chemical and physical carcinogens; inactivation and dysregulation of tumor suppressor genes by chemical and physical
Recent molecular characterizations of Cryptosporidium parasites make it possible to differentiate the human-pathogenic Cryptosporidium parasites from those that do...Full Text Available
BackgroundMany molecules of interest are flexible and undergo significant shape deformation as part of their function, but most existing methods of molecular shape comparison (MSC)...Full Text Available
Radioadapted chicken embryo cells (X-irradiation in ovo with 10 cGy at the 14th day of development with priming periods of 24 h) were treated in vitro by challenge doses of 14 different DNA- and/or chromatin-interactive agents, including X-rays. A decrease in the cellular damage, as measured by scheduled DNA synthesis, was only observed with X-irradiation. Sedimentation of nucleoids as well as viscosity of alkaline lysates from ethidium bromide (0.35-400 {mu}g/ml)-, vovobiocin (125-1800 {mu}g/ml)-, and hyperthermia (30 min at 43 and 45 )-treated cells suggest a higher tendency of radioadapted cells to undergo positive DNA supercoiling. When DNA from adapted and non-adapted chicken embryo cells was used as substrate, neither its digestion by DNase I nor the inhibition of DNase I activity by various DNA-interactive agents was changed in primed cells. From the previous investigations as well as from the present results it is concluded that an increase of tightening of protein-DNA ...
The present article outlines major features of the free electron laser (FEL) and reviews research and development of FEL. Relations among the oscillation frequency, electron beam parameters and wiggler parameters, the physical mechanism of amplification and the physical process of saturation are discussed to identify the difference between FEL and other lasers. The report also outlines techniques for accelerators which are used to generate high-quality, high-energy electron beams required for FEL experiments. Techniques to achieve a short wavelength, high output and high efficiency, and applications of FEL are also discussed. FEL consists of an electron accelerator, wiggler and optical resonator. In FEL, electron beams with a relativistic energy interact resonantly with an electromagnetic field to generate coherent electromagnetic waves. Unlike conventional lasers, FEL does not surfer from restrictions on its oscillation frequency associated with atomic, molecular ...
We present an approach for fabrication of intentionally positioned epitaxial InAs QDs in a micron sized light emitting diode. For site-selective growth, a combination of molecular beam epitaxy (MBE) and focused ion beam (FIB) implantation technology in an all-ultra-high-vacuum (UHV) setup has been employed. Single dot occupancy of almost 55 % on FIB patterned nano-depressions was successfully achieved. Thereafter, carrier injection and subsequent radiative recombination from the positioned InAs/GaAs self-assembled QDs was investigated by embedding these QDs in the intrinsic part of a GaAs-based micron sized p-i-n junction device. Few or single dot are expected to be electrically addressed in these devices. We report results from electroluminescence (EL) measurement which proves the single dot characteristics of our device. The EL spectra consist of sharp emission lines and their dependence on injection current shows linear behavior for exciton ...
As a series of experimental determinations of the thermal diffusivity of molten alkali halides, this paper describes measurements on five molten alkali metal chlorides (LiCl, NaCl, KCl, RbCl, and CsCl) in the temperature range up to 1440 K by the forced Rayleigh scattering method. K[sub 2]Cr[sub 2]O[sub 7] is employed as a dye substance to color the transparent molten salts. In comparison with the present results converted into thermal conductivity, most of the previous experimental data obtained by steady-state methods show larger values, up to about five times, which may be due to the systematic error caused by the presence of convection and radiation. It is found that the thermal conductivity of these series of molten alkali metal chlorides decreases with increasing molecular weight, and their temperature coefficients are weakly negative. 24 refs., 9 figs., 6 tabs.
Decommissioning of radiological and nuclear installations is for this century the new challenge. One of the performance criteria is the reduction of total quantities of radioactive materials (liquid or solid) arising from dismantling and decontamination of radiological and nuclear installations. In this work we present a new application of the water soluble polymers used as: - flocculation agents in treatment and conditioning process within the management of radioactive liquid materials; - strippable coatings on solid materials based on the water soluble polymers. The parameters of water soluble polymers made in our Institute by radiation processing have been analysed, namely the molecular average weight, composition, and efficiency of utilization of these polymeric materials as well as the content of ash, additives, decontamination factor, consumption per surfaces/liter, corrosion aspects, compatibility with various surfaces (of metal, ...
IRAM 30m observations reveal that the deeply obscured IR-luminous galaxy NGC4418 has a rich molecular chemistry - including unusually luminous HC3N line emission. We furthermore detect: ortho-H2CO 2-1, 3-2; CN 1-0, 2-1; HCO+, 1-0. 3-2, HCN 3-2, HNC 1-0, 3-2 (and tentatively OCS 12-11). The HCN, HCO+, H2CO and CN line emission can be fitted to densities of n=5 x 10E4 - 10E5 cm-3 and gas temperatures Tk=80-150 K. Both HNC and HC3N are, however, significantly more excited than the other species which requires higher gas densities - or radiative excitation through e.g. mid-IR pumping. The HCN line intensity is fainter than that of HCO+ and HNC for the 3-2 transition, in contrast to previous findings for the 1-0 lines where the HCN emission is the most luminous. We tentatively suggest that the observed molecular line emission is consistent with a young starburst, where the emission can be understood as emerging from dense, warm ...
The finite-volume based commercial CFD-code Fluent was used to simulate the reacting flow in a heavy fuel oil fired laboratory furnace. Both the standard {kappa}-{epsilon} turbulence model and the Reynolds stress model (RSM) were tested. The combustion model was based on the conserved scalar (mixture fraction) and prescribed probability density function approach. The heavy fuel oil droplet trajectories were predicted by solving the momentum equations for the droplets using the Lagrangian treatment. The soot distribution in the furnace was calculated by solving a transport equation for the soot mass fraction. Simple expressions for the soot formation and oxidation rates were employed. The radiation heat transfer equation was solved using the finite volume method. The formation of thermal NO from molecular nitrogen was modeled according to the extended Zeldovich mechanism. Fuel-based NO was modeled assuming that all the nitrogen in the fuel is ...
The collapse and fragmentation of initially prolate and oblate, magnetic molecular clouds is calculated in three dimensions with a gravitational, radiative hydrodynamics code. The code includes magnetic field effects in an approximate manner: magnetic pressure, tension, braking, and ambipolar diffusion are all modeled. The parameters varied for both the initially prolate and oblate clouds are the initial degree of central concentration of the radial density profile, the initial angular velocity, and the efficiency of magnetic braking (represented by a factor f _m_b = 10"-"4 or 10"-"3). The oblate cores all collapse to form rings that might be susceptible to fragmentation into multiple systems. The outcome of the collapse of the prolate cores depends strongly on the initial density profile. Prolate cores with central densities 20 times higher than their boundary densities collapse and fragment into binary or quadruple systems, whereas cores with ...
This is the second revision of the ETDE/INIS Joint Thesaurus, including all updates up to September 2006. It contains 21 147 valid descriptors and 9 114 forbidden terms. The Joint Thesaurus contains the controlled terminology for indexing all information within the subject scopes of the International Nuclear Information System (INIS) and the Energy Technology Data Exchange (ETDE). The terminology is intended for use in subject descriptions for input or retrieval of information in these systems. The thesaurus is a terminological control device used in translating from the natural language of documents, indexers or users into a more constrained system language It is also a controlled and dynamic vocabulary of semantically and generically related terms which covers a specific domain of knowledge. The basic terminology in this thesaurus goes back to the 1969 edition of the EURATOM Thesaurus. The structure subsequently given to that terminology was the result of a systematic study performed ...
...Correction Discussion Editorial Letter Opinion Review Short Note Technical Note Special Issue all A Systematic Development Method for Rational Drug Design Advances in Molecular Electronic Structure Calculations Algorithms and Molecular Sciences Antimicrobial Agents Application of Density Functional Theory Applications of Density Functional Theory Applications of Molecular Dynamics Atoms in Molecules ...
Contents The aim of this study was a cytogenetic analysis of stallions semen to find sex chromosome aberrations and to determine if there was an association between stallion-s age and aberration frequency for the sex chromosomes. Sperm samples were collected from 22 stallions of various age from 3 to 23-years. Multicolour FISH was performed on each sample, using probes for the sex chromosomes and EGFR gene, localized on 4p12 in domestic horse. A total of 26199 sperm cells were analysed (from 1 070 to 1 532 per animal). Among the analysed cells, there were 50.318% with X chromosome, 48.543% with Y chromosome and 1.139% with aberrant chromosomes. The frequency of aberrations was: sex chromosomes nullisomy (0.466%), XY aneuploidy (0.454%), XX disomy (0.146%), YY disomy (0.041%), diploidy (0.0...
Radiotherapy with high-energy carbon ion beams can be more advantageous compared to photons because of better physical dose distribution and higher biological efficiency in tumour cell sterilization. Despite enhanced normal tissue sparing, damage incurred by normal cells at the beam entrance is unavoidable and may affect the progeny of surviving cells in the form of inheritable cytogenetic alterations. Furthermore, the quality of the beam along the Bragg curve is modified by nuclear fragmentation of projectile and target nuclei in the body. We present an experimental approach based on the use of a polymethylmethacrylate (PMMA) phantom that allows the simultaneous exposure to a particle beam of several biological samples positioned at various depths along the beam path. The device was used to measure the biological effectiveness of a 60 MeV/amu carbon-ion beam at inducing chromosomal aberrations in G{sub 0}-human peripheral blood lymphocytes. Chromosome spreads were ...
The recently described retinoid X receptors (RXRs) respond to the novel retinoid 9-cis-retinoic acid and also serve as heterodimeric partners for the vitamin D, thyroid hormone, and retinoic acid receptors (VDR, TR, and RAR, respectively). In this work, the authors report high-resolution localization of the human RXR genes within cytogenetic bands and also within a standard reference map of cosmid DNA markers on human chromosomes. They have determined the location of the human RXR genes by pairwise hybridization of the RXR cosmids and reference markers, using fluorescence in situ hybridization. They localized (i) RXR[alpha] (RXRA) to chromosome 9 band q34.3; (ii) RXR[beta] (RXRB) to chromosome 6 band 21.3; and (iii) RXR[gamma] (RXRG) to chromosome 1 band q22-q23. Six retinoid-responsive transcription factors have been identified so far, including three retinoic acid receptors in addition to the three RXRs. Interestingly, each of these receptors in human and mouse ...
Abstract The authors provide a survey of how images are used in radiation therapy to improve the precision of radiation therapy plans, and delivery of radiation treatment. In contrast...Full Text Available
... radiation during clinical therapy and exposures due to radiation accidents or attacks, in which the doses are uncontrolled ... only be used off-label in victims of radiation accidents or attacks. The idea...
The biomedical and ecological interest for the microwave impact on the Earth biosphere is continuously increased since the industrial, military and communication activities strongly contribute to the electromagnetic stress of living bodies. In the next the authors present some of the main results obtained regarding the microwave exposure of various types of biological material: bacteria, fungi, young plant seedlings, dry seeds, animal tissues. The electromagnetic exposure was carried out in open space in well controlled environmental conditions by using 10.75 GHz/1 m W cm{sup -2} microwaves. Biochemical assays and cytogenetic tests have been carried out to reveal the changes induced post irradiation. The response of some pathogen bacteria, have been emphasized by means of turbidimetric measurements - the stimulatory effect being noticed at the level of the microbial population density (the stimulation of the human body microbial flora seems to be one of the side ...
Full text: As you know, thin films which generate anomalous big photovoltage (APhV) , as film photo resistive structures made of the combinations of A_2B_6 respond to X-ray and #gamma#- radiations. In this work the influence of X-ray and #gamma#-radiations on the quantity of APhV in the system APhV-film-photoresistor was investigated. Earlier polycrystal films with anomalous photo voltage properties were received only on the clean and flat surface with high isolation property (R>10"1"4 #OMEGA#). We worked out the technology of receiving APhV films CdTe on the surface of the photosensitive film CdS. The main condition under which this effect may be observed is that the lining must be slant concerning to the direction of the motion of evaporated substance's molecular bunch during the growing of the film, i.e. received film must have a dendritic structure. That is why photosensitive film CdS was received with thermo vacuum ...
Radio-biologists have pointed out a novel radiobiological phenomenon observed in many tumor and normal cell lines: hyper-radiosensitivity to very low-dose (H.R.S.) followed by induced radioresistance (I.R.R.) after a threshold dose of 0.1-0.3 Gy that depends on the cell line. Radioresistance at high dose (i.e. higher than 0.5 Gy) and metastatic potential of tumor cells are likely major factors of failure in radiotherapy. A careful review of literature suggests that: 1) radiotherapy does not increase the metastatic potential of tumor cells; 2) radioresistance at high dose and metastatic potential are not related. However, inside a given tumor cell line, highly metastatic clones may elicit more cells showing H.R.S; or are more radiosensitive at high dose than poorly metastatic ones. Recent data obtained from molecular techniques (comet and immunofluorescence assays) applied to single cells irradiated at very low radiation doses (1-100 mGy) ...
Efforts to assess and quantify deleterious effects from toxicants concentrate mainly on single agents whereas real world environmental and occupational exposures to natural and anthropogenic agents entail quite often the concomitant presence of several toxicants. For occupational important exposure situations, combined exposures to physical and chemical agents such as radon and smoking or asbestos and smoking, respectively, were shown to produce over-additive effects at exposure levels typical for earlier workplaces. Already the elucidation of possible health risks from a single agents, its dependence on exposure level, exposure rates, age at exposure and its expression in time is a complex endeavour. Therefore in the past and the present the main emphasis in radiation protection, toxicology, and public health is on the study and assessment of single toxicants. The existing data base on combined effect is rudimentary, mainly descriptive and rarely covers exposure ...
The case of spontaneous radiation of channeled ultrarelativistic particles is considered when the dipolarity condition is not satisfied. The change of the particle longitudinal velocity affecting the maximum radiation frequency is included. The angular and frequency characteristics of the radiation for superhigh energies are studied for the first time. It is shown that there is an optimum energy at which the radiation density is maximum. The influence of the angle at which electrons enter a crystal and of the beam divergence on the radiation is investigated. The problem of quasichanneled particle radiation and also the radiation in axis-plane transitions are considered. (author).
Systematics of neutron capture radiative width were studied in the target element range from Th to Cm. Reduced radiative widths were analyzed with a simple radiative width formula based on E1 transition. Average radiative width is presented with the standard deviation of 15%. (author)
Molecular Misreading (MM) is the inaccurate conversion of genomic information into aberrant proteins. For example, when RNA polymerase II transcribes a GAGAG motif it synthesizes at low frequency RNA...Full Text Available
Earlier we have shown that exogenous expression of HIPPI, a molecular partner of Huntingtin interacting protein HIP-1, induces apoptosis and increases expression of caspases-1, -8 and -10 in HeLa and...Full Text Available
AbstractWe combined atomistic molecular-dynamics simulations with quantum-mechanical calculations to investigate the sequence dependence of the stretching behavior of duplex DNA. Our...Full Text Available
Solid molecular orthohydrogen exhibits orientational order at low temperatures. The orthohydrogen molecules, which are quadrupoles, order in the Pa3 structure. We have simulated this ordering, and explored the behaviour under dilution by spherical parahydrogen molecules.
AbstractStudies performed to identify early events of ovarian cancer and to establish molecular markers to support early detection and development of chemopreventive regimens have been...Full Text Available
In this study we compared the molecular signalling elicited by rexinoids, selective retinoid X receptor (RXR)-activators, in several organs (i.e. liver, kidney,...Full Text Available
A parallel bundle of transmembrane (TM) alpha-helices surrounding a central pore is present in several classes of ion channel, including the nicotinic acetylcholine receptor (nAChR). We have modeled...Full Text Available
A new gadolinium chelating NIR fluorescent molecular probe increases T1 relaxivity of water protons, facilitating combined optical and magnetic resonance imaging.
This article describes the molecular cloning and expression of a hemolysin gene from a serotype 1 strain of Actinobacillus pleuropneumoniae. The hemolysin was a thermolabile protein with an apparent...Full Text Available
The overall objective of this project was to use molecular genetics to develop strains of bacteria with enhanced ability to remove sulfur from coal, and to obtain data that will allow the performance and economics of a coal biodesulfurization process to be predicted. (VC)
Combined QM(PM3)/MM molecular dynamics simulations together with QM(DFT)/MM optimizations for key configurations have been performed to elucidate the enzymatic catalysis mechanism on the detoxification...Full Text Available
A detailed molecular characterization of nuclear mRNA export will require an in vitro system, allowing a biochemical reconstitution of transport. To this end, an mRNA export assay has...Full Text Available
Molecular life science is one of the fastest-growing fields of scientific and technical innovation, and biotechnology has profound effects on many aspects of daily life—often with deep, ethical...Full Text Available
MWo = average molecular weight of fuel est. 105 g/mole for gasoline est. 165 g/mole for Jet fuel est. 230 g/mole for diesel fuel MWX = molecular weight of selected chemical...
One of the central questions of molecular biology is the discovery of the semantics of DNA. This discovery relies in a critical way on a variety of expensive computations. In order to solve these computations, both parallel computers and special-purpose hardware play a major role.
The molecular diversity of the gene encoding the outer membrane protein A (OmpA) of Haemophilus parasuis has been unclear. In this study, the structural characteristics, sequence types,...Full Text Available
BackgroundHealth risk from exposure of perfluorochemicals (PFCs) to wildlife and human has been a subject of great interest for understanding their molecular mechanism of toxicity....Full Text Available
Alpha-hemoglobin-stabilizing protein (AHSP) is an erythroid-specific protein that acts as a molecular chaperone for the free α chains of hemoglobin. Evidence strongly suggests...Full Text Available
The batchwise preparation of molecular sieves for methanol conversion shows some inconsistency in catalytic stability. This is a result mainly of the change of SiO/SUB/2/Al/SUB/2O/SUB/3 in ion exchange to an H-type sieve. The dealumination during ion exchange depends upon crystal size and structural factors, which can be characterised by the cyclohexane adsorption of the raw molecular sieve. A high SiO/SUB/2/Al/SUB/2O/SUB/3 H-molecular sieve can be prepared from a molecular sieve of high adsorption capacity, this leading to a catalyst of higher stability. (4 refs.)
Despite their simplicity, diatomic molecules of first row elements can exhibit very complex phase diagrams. Determination of the phase diagrams can be further complicated by the existence of hysteretic molecular phases that can be observed over large regions of coexistence. Here we present evidence for a previously unreported molecular phase of nitrogen existing at room temperature at least over the range of 33-74 GPa. Our measurements show that sample history may have a significant impact on the thermodynamic states accessed by the molecular nitrogen solid and, by extension, also on the established phase diagram.
Most of the investigations have a theoretical sustenance based on molecular simulation. The area of application of molecular simulation is very wide, in the Materials Technology Department assigned to the Applied Sciences Management have been treated problems about metallic nano structures, glasses, interfaces, and molecules, to sustain and to explain some of the experimental results. Energy calculations are carried out to determine minimum energy structures, for later on to carry out calculations of some of their properties; as well as the images simulation of Electron microscopy and X-ray diffraction. (Author)
Objective: To develop a computerized method of internal dose estimation on radiation protection. Methods: Based on MIRD mathematic model of the organs and by means of the programming language of MS Visual Basic 6.0, a computer program of dose estimation in internal radiation was developed for radiation protection. Results: The computerized method of dose estimation for internal radiation was completed. Conclusions: This computerized method is very convenient for internal radiation dose estimation of several aspects. It can also be used in radiation accident. (authors)
Scheme of theoretical method of molecular configuration definition for small organic molecules in solution has been presented. The method bases on measurements of nuclear Overhauser effects for proton-proton interactions and molecular mechanics calculations. 3 refs, 1 fig.
German translation of the publication 'The evaluation of risks from radiation' published in 1965 by the International Commission on Radiological Protection. In a survey, genetic and somatic risks from radiation are presented and explained. (HP).
This book gives an overview of the entire field of radiation protection with the subject areas radioactivity, X-rays, UV radiation, laser beams and high-frequency electromagnetic fields. It deals graphically with the most important physical notions, the incidence, origin, properties and biological effects of types of radiation, administrative and practical protection measures and the code of rules governing them. Apart from fundamentals of radiation protection the emphasis on the following: natural radiation exposure, radiation exposure to radon, disaster relief plans in the environment of nuclear plant, the precautionary radiation protection system evolved after Chernobyl, radiation exposure through UV radiation devices, radio, RF communication, radar, microwave ovens and high-voltage transmission ...
The analysis of oceanographic lidar systems measurements is often carried out with semi-empirical methods, since there is only a rough understanding of the effects of many environmental variables. The development of techniques for interpreting the accuracy of lidar measurements is needed to evaluate the effects of various environmental situations, as well as of different experimental geometric configurations and boundary conditions. A Monte Carlo simulation model represents a tool that is particularly well suited for answering these important questions. The PREMAR-2F Monte Carlo code has been developed taking into account the main molecular and non-molecular components of the marine environment. The laser radiation interaction processes of diffusion, re-emission, refraction and absorption are treated. In particular are considered: the Rayleigh elastic scattering, produced by atoms and molecules with small dimensions with ...
Iguanian lizards form a diverse clade whose members have been the focus of many comparative studies of ecology, behavior, and evolution. Despite the importance of phylogeny to such studies, interrelationships among many iguanian clades remain uncertain. Within the Old World clade Acrodonta, Agamidae is sometimes found to be paraphyletic with respect to Chamaeleonidae, and recent molecular studies have produced conflicting results for many major clades. Within the largely New World clade Pleurodonta, relationships among the 12 currently recognized major subclades (mostly ranked as families) have been largely unresolved or poorly supported in previous studies. To clarify iguanian evolutionary history, we first infer phylogenies using concatenated maximum-likelihood (ML) and Bayesian analyses of DNA sequence data from 29 nuclear protein-coding genes for 47 iguanian and 29 outgroup taxa. We then estimate a relaxed-clock Bayesian chronogram for iguanians using BEAST. ...
The present invention relates generally to an apparatus and method for separating high molecular weight molecules from low molecular weight molecules. More specifically, the invention relates to the use of microdialysis for removal of the salt (low molecular weight molecules) from a nucleotide sample (high molecular weight molecules) for ESI-MS analysis. The dialysis or separation performance of the present invention is improved by (1) increasing dialysis temperature thereby increasing desalting efficiency and improving spectrum quality; (2) adding piperidine and imidazole to the dialysis buffer solution and reducing charge states and further increasing detection sensitivity for DNA; (3) using low concentrations of dialysis buffer and shifting the DNA negative ions to higher charge states, producing a nearly 10-fold increase in detection sensitivity and a slightly decreased desalting efficiency, or (4) ...
In this paper we discuss the results of thermoluminescence (TL) studies carried out on freshly quenched crystals of KBr doped with {approx} 50 ppm of Eu{sup 2+} ions which were X-irradiated at room temperature. The TL glow curve of this phosphor material consists of three glow peaks at 355, 376 and 398 K whose intensities increased as a function of X-irradiation time. The TL glow peaks were analyzed by the total curve-fitting method in order to obtain the characteristic parameters; activation energy, pre-exponential factor and kinetic order. The spectral character of the emission recorded during thermoluminescence was found to be the same for all glow peaks and consists of a broad band centered at {approx} 420 nm. It is proposed that the model of the TL process most consistent with our experimental results is one in which the Eu{sup 2+} impurity acts as an electron trap during the irradiation process and that the radiation induced center (partner of an center) and ...
In this paper we discuss the results of thermoluminescence (TL) studies carried out on freshly quenched crystals of KBr doped with #approx# 50 ppm of Eu"2"+ ions which were X-irradiated at room temperature. The TL glow curve of this phosphor material consists of three glow peaks at 355, 376 and 398 K whose intensities increased as a function of X-irradiation time. The TL glow peaks were analyzed by the total curve-fitting method in order to obtain the characteristic parameters; activation energy, pre-exponential factor and kinetic order. The spectral character of the emission recorded during thermoluminescence was found to be the same for all glow peaks and consists of a broad band centered at #approx# 420 nm. It is proposed that the model of the TL process most consistent with our experimental results is one in which the Eu"2"+ impurity acts as an electron trap during the irradiation process and that the radiation induced center (partner of an center) and the V_k ...
Analysis by gas chromatography-mass spectrometry and high performance liquid chromatography has revealed organic residues in sup(99m)Tc-pertechnetate obtained from "9"9Mo-molybdate by extraction, using the organic solvent methylethylketone (MEK). The organic residues have been identified as either (i) low molecular weight carbonyl compounds such as formaldehyde, acetaldehyde and acetone, presumably caused by the effects of #gamma#-radiation on MEK, or (ii) condensation products resulting from the action of strong alkali on MEK during the extraction process. The quantities of organic residues varied from batch to batch of extracted pertechnetate; up to 40 #mu# mL"-"1 was found. When these compounds were tested, in rats, by addition to a pyrophosphate bone-seeking radiopharmaceutical, the tissue distribution was not significantly different from that in the control, which contained no added compound. Assay for "9"9Tc in MEK-derived pertechnetate ...
Several short-lived, high-energy beta emitters are being proposed as the radionuclide components for molecular-targeted potential cancer therapeutic agents. The laboratory mice used to determine the efficacy of these new agents have organs that are relatively small compared to the ranges of these high-energy particles. The dosimetry model developed by Hui et al. was extended to provide realistic beta-dose estimates for organs in mice that received therapeutic radiopharmaceuticals containing 90Y, 188Re, 166Ho, 149Pm, 64Cu, and 177 Lu. Major organs in this model included the liver, spleen, kidneys, lungs, heart, stomach, small and large bowel, thyroid, pancreas, bone, marrow, carcass, and a 0.025-g tumor. The study as reported in this paper verifies their results for 90Y and extends them by using their organ geometry factors combined with newly calculated organ self-absorbed fractions from PEREGRINE and MCNP. PEREGRINE and MCNP agree to within 8% for the worst-case ...
Combination of radiotherapy and chemotherapy (CRC) is actually one important way of research in oncology. Theoretical advantages are: (1) Spatial cooperation; (2) Additivity, which is only obtained if the toxicity of each modality are different; (3) Supra-additivity, which needs a rigorous in vitro definition; the only way to prove it is to make an isobologram analysis. This model has however, some limitations: qualitative variable could not be used, results could be different, depending on the cell line and isoeffect chosen...In fact, a supra-additivity was only demonstrated for cis platinum and etoposide. Interactions mechanisms were: (1) at the molecular level, creation of new lesions or inhibition of radiation lesions repair; (2) At the cellular level, either cytokinetic cooperation with S-phase dependent drugs, or synchronization for the drugs which blocked the cells in M-phase; (3) At the tissular level, reoxygenation, cycle ...
Molecular imaging represents a modern research area that allows the in vivo study of molecular biological process kinetics using appropriate probes and visualization methods. This methodology may be defined- apart from the contrast media injection - as non-abrasive. In order to reach an in vivo molecular process imaging as accurate as possible the effects of the used probes on the biological should not be too large. The contrast media as important part of the molecular imaging can significantly contribute to the understanding of molecular processes and to the development of tailored diagnostics and therapy. Since more than 15 years PTB is developing optic imaging systems that may be used for fluorescence based visualization of tissue phantoms, small animal models and the localization of tumors and their predecessors, and for the early recognition of inflammatory processes in ...
Subject to the provisions of the Radiation Protection Act, the Authority, on the advice of ...(f) in collaboration with the Radiation Protection Board, conduct an ionising radiation monitoring programme and ...or document kept under the control of the Radiation Protection Board.
Described and discussed in this paper are radiation processes and their advantages over the conventional techniques. Radiation sterilization of medical products, food irradiation, wood plastic composites, and radiation treatment of sewage and waste waters are presented. The Philippine experience in using these technologies, its problems and barriers are also given. (ELC).
This text-book (electronic book - multi-media CD-ROM) constitutes a course-book - author's collection of lectures. It consists of 13 lectures in which the reader acquaints with the basis of radiobiology: Introduction to radiobiology; Physical fundamentals of radiobiology; Radiation of cells; Modification of radiation damage of cells; Reparation of radiation damage of cells; Radiation syndromes and their modification; Radiation injury; Radiation damage of tissues; Effect of radiation on embryo and fetus; Biological effects of incorporated radionuclides; Therapy of acute irradiation sickness; Delayed consequences of irradiation; Radiation oncology and radiotherapy. This course-book may be interesting for students, post-graduate students of chemistry, biology, physics, medicine as well as for teachers, scientific workers ...
... Radiation Protection Products and Equipment Find and compare a variety of radiation protection products and equipment on the world's largest environmental industry portal. View product ...
This chapter is concerned with standards and guidances for limiting radiation exposures. It is divided into three sections, each of which has several parts. Section 1: Ionizing Radiation -- Standards and Guidances Applicable to the Public: Part A, Radiation Protection Standards; Part B, Environmental Radiation Standards; Part C, Exempt Levels of Radioactivity; Part D, Protective Action Guides for Accidents. Section 2: Ionizing Radiation -- Standards Applicable to the Workplace. Section 3: Medical and Other Standards.
On the basis of legally provided area dose measurements and time records of fluoroscopic examinations during the operation, radiation doses to medical personnel and patients are evaluated. Adequate radiation protection measures and a careful behaviour in the operating room keep the radiation exposure to the personnel below the maximum permissible exposure. Taking into account the continuous personnel radiation monitoring and medical supervision, radiation hazards in the operating room can be considered low.
The current state and need for radiation protection training in Finland have been surveyed by the Radiation and Nuclear Safety Authority STUK. The survey sought to determine whether the current requirements for radiation protection training had been met, and to promote radiation protection training. Details of the scope and quality of present radiation protection training were requested from all educational institutes and organizations providing radiation protection training. The survey covered both basic and further training, special training of radiation safety officers, and supplementary training. The questionnaire was sent to 77 educational organization units, 66 per cent of which responded. Radiation workers and radiation safety officers were asked about radiation protection ...
We report the arcsecond resolution SMA observations of the $^{12}$CO (2-1) transition in the massive cluster forming region G10.6-0.4. In these observations, the high velocity $^{12}$CO emission is resolved into individual outflow systems, which have a typical size scale of a few arcseconds. These molecular outflows are energetic, and are interacting with the ambient molecular gas. By inspecting the shock signatures traced by CH$_{3}$OH, SiO, and HCN emissions, we suggest that abundant star formation activities are distributed over the entire 0.5 pc scale dense molecular envelope. The star formation efficiency over one global free-fall timescale (of the 0.5 pc molecular envelope, $\\sim$10$^{5}$ years) is about a few percent. The total energy feedback of these high velocity outflows is higher than 10$^{47}$ erg, which is comparable to the total kinetic energy in the rotational motion of the dense ...
The assumed linear relationship between exposure to radiation and cancer incidence is questioned in this article. The current research data on radiation effects at the cellular level is reviewed, as are epidemiological studies of background radiation effects and health effects of populations exposed to low levels of radiation exposure via employment or medical treatments. Statistics reveal that threshold levels currently in force need to be reviewed. Some evidence of beneficial effects of low level radiation exposure effects of low level radiation exposure is also presented, and so regulations should be reviewed at an international level. (UK).
The most propagated mechanisms of stimulated radiation of electron beam such as Cherenkov one-particle and collective effects, ondulator and magnetic bremsshrahlung radiations, Doppler anomalous effect, Thompson and Raman scattering and radiation are discussed. Relation of spontaneous radiation mechanisms of individual electron and stimulated radiation effects in electron beams has been elucidated, grounds of linear electrodynamics of radiative beam instabilities are stated, and main mechanisms of their nonlinear stabilization are elucidated as well. Various simulated processes in electron beams are considered from the unique point of view using a simple mathematical apparatus and such physical laws as conservation and Newton laws.
We describe a class of organic molecular magnets based on zwitterionic molecules (betaine derivatives) possessing donor, p bridge, and acceptor groups. Using extensive electronic structure calculations we show the electronic ground-state in these systems is magnetic. In addition, we show that the large energy differences computed for the various magnetic states indicate a high Neel temperature. The quantum mechanical nature of the magnetic properties originates from the conjugated p bridge (only p electrons) in cooperation with the molecular donor-acceptor character. The exchange interactions between electron spin are strong, local, and independent on the length of the p bridge.
The thermodynamic characteristics of adsorption of iodobenzene, 2-iodothiophene, and 1- and 2-iodoadamantanes on the surface of graphitized thermal carbon black were determined experimentally. The influence of the special features of the molecular structure of the adsorbates on the thermodynamic characteristics of adsorption was studied. The atom-atom approximation of the semiempirical molecular-statistical theory of adsorption was used to calculate the thermodynamic characteristics of adsorption of the adsorbates using the newly determined potential function parameters of pair intermolecular interaction (?(r)) of I with C atoms of the basal graphite face. For the example of isostructural monohalogenated benzenes, thiophenes, and adamantanes, a comparative analysis of the contributions of ...
The first candidate rotavirus vaccine was a live attenuated oral vaccine made by the classical empirical method of serial passage of virus in tissue culture cells. Current tetravalent vaccine candidates that are in the final stages of efficacy testing in the United States were made by genetic reassortment. This article briefly highlights how advances in the basic understanding of the molecular biology of rotaviruses have facilitated vaccine development. New approaches for second-generation vaccines and improvements in vaccine efficacy based on further exploitation of the tools and knowledge of rotavirus molecular biology and pathogenesis are discussed. PMID:8752289
Ultraviolet photoelectron spectra were measured for vanadyl phthalocyanine (VOPc) ultrathin films prepared on graphite to study effects of the molecular orientation and the electric dipole layer on the organic electronic states. VOPc has a permanent electric dipole perpendicular to the molecular plane, hence a well-defined electric dipole layer could be intentionally prepared by using the oriented monolayer. The observed binding-energy difference of the highest occupied molecular orbital (HOMO) bands between the oriented monolayer and the double layer was found to agree with the vacuum level shift, leading to a conclusion that the molecular energy level with respect to the substrate Fermi level is changed when the molecule is in the electric dipole layer.
Advances in molecular technologies challenge the different concepts of causality in biology, epidemiology and multistage mathematical models. The lack of integration of the different aspects of causality...Full Text Available
The receptor-associated protein (RAP) is a molecular chaperone that binds tightly to certain newly synthesized LDL receptor family members in the endoplasmic reticulum (ER) and facilitates their delivery...Full Text Available
The molecular structure, chemical properties, and biological function of the xyloglucan polysaccharide isolated from cell walls of suspension-cultured sycamore (Acer pseudoplatanus)...Full Text Available
For a process intimately connected to an immense range of physiological processes, the molecular understanding of macroautophagy remains far from complete. Recent large-scale studies, including...Full Text Available
ConspectusSelf-assembly allows for the preparation of highly complex molecular and supramolecular systems from relatively simple starting materials. Typically, self-assembled...Full Text Available
BackgroundOrthology analysis is an important part of data analysis in many areas of bioinformatics such as comparative genomics and molecular phylogenetics. The ever-increasing flood...Full Text Available
The use of Funtumia latex and nitrobenzene as molecular weight depressants for natural rubber was studied. Portions of a given sample of natural rubber latex were treated with these materials, and this provided a means of ascertaining the amount of Funtumia latex in a blend with natural rubber that could produce a lowering of the molecular weight equivalent to that from known concentrations of nitrobenzene in natural rubber latex. The molecular weight of the products decreased to an equilibrium value after 10 h of reaction with nitrobenzene. The calculations revealed that a 27.9% substitution of natural rubber latex (300 mL) with Funtumia rubber latex achieved the same result as nitrobenzene in the same polymer at concentrations of 0.5-2.0 wt % of the dry rubber content of the latex after ...
Orphan G protein-coupled receptors (GPCRs) are receptors lacking endogenous ligands. Found by molecular biological analyses, they became the roots of reverse pharmacology, in which receptors are attempted...Full Text Available
A new method of the synthesis of high molecular polybutylene terephthalate (PBT) is developed with the use of Irganox 1010, tris(nonylphenyl) phosphite and hypophosphite as stabilizers and boron nitride or boron oxide as a catalyst is proposed.
Comparative Molecular Genetic Monitoring of Myxoviruses Circulating in Populations of Seals Phoca Caspia and Phoca Sibirica in Northern Caspian Region and Lake Baikal
... Here we will summarize the synthesis, structure activity relationships , and molecular sites of action of mGluR5 PAMs. We will also review preclinical studies ...
These proceedings collect papers on the subject of lymphokines. Topics include: DNA-cloning of mouse and human lymphokine genes, inteferons, interleukins, gene expression, tumor necrosis factors, and recombinant DNA.
Cellular actions of thyroid hormone may be initiated within the cell nucleus, at the plasma membrane, in cytoplasm, and at the mitochondrion. Thyroid hormone nuclear receptors (TRs) mediate the biological...Full Text Available
BackgroundMolecular genetic studies of Bombyx mori have led to profound advances in our understanding of the regulation of development. Bombyx mori brain,...Full Text Available
We investigate the magnetic braking of the core of an axisymmetric cloud whose rotation axis is parallel to the mean direction of the magnetic field. (author).
The Liver Carcinogenesis Section uses the modern technologies of molecular biology, cell biology, protein chemistry and genetics to investigate the biochemical and genetic pathways involved in human liver cancer.
To establish a relationship between the molecular structure of polycarboxylates and their growth-retarding influence on barium sulfate, seeded-suspension-growth experiments were performed at various inhibitor concentrations and pH values. Two types of polycarboxylates with a molecular structure based on their polyacrylic or maleic acid were studied. The molecular structure of these compounds were varied by particle substitution with monomers containing hydroxyl, amide, and sulfonic acid, as well as hydrophobic groups. Hydrophobic groups are detrimental to good inhibitor performance, whereas the introduction of OH, NH {sub 2}, or SO {sub 3} H groups presents opportunities to enhance the inhibitor effectiveness. The sequence in performance of the compounds on barium sulfate was compared with the sequence formerly obtained for calcium sulfate dihydrate.
The nitric oxide molecule is being studied in order to understand the energetics and chemistry of initiation and detonation in liquid NO at the molecular level. An overview is presented of the work being done. (DLC)
Advances in modern neuroscience require the identification of principles that connect different levels of experimental analysis, from molecular mechanisms to explanations of cellular functions,...Full Text Available
We investigate the chemical and observational implications of repetitive transient dense core formation in molecular clouds. We allow a transient density fluctuation to form and disperse over a period of 1 Myr, tracing its chemical evolution. We then allow the same gas immediately to undergo further such formation and dispersion cycles. The chemistry of the dense gas in subsequent cycles is similar to that of the first, and a limit cycle is reached quickly (2 - 3 cycles). Enhancement of hydrocarbon abundances during a specific period of evolution is the strongest indicator of previous dynamical history. The molecular content of the diffuse background gas in the molecular cloud is expected to be strongly enhanced by the core formation and dispersion process. Such enhancement may remain for as long as 0.5 Myr. The frequency of repetitive core formation should strongly determine the level of background ...
The biosynthesis of insect juvenile hormone (JH) and its neuroendocrine control are attractive targets for chemical control of insect pests and vectors of disease. To facilitate the molecular...Full Text Available
Mutations in the Drosophila gene drop-dead (drd) result in early adult lethality and neurodegeneration, but the molecular identity of the drd...Full Text Available
Aggregatibacter (Actinobacillus) actinomycetemcomitans is a facultative anaerobic gram-negative bacterium associated with severe forms of periodontitis. A leukotoxin, which belongs...Full Text Available
Physiological bone remodeling is a highly coordinated process responsible for bone resorption and formation and is necessary to repair damaged bone and to maintain mineral homeostasis. In addition to...Full Text Available
This manual was written for individuals who wish to become qualified in radiation protection as an adjunct to working with sources of ionizing radiation or using radionuclides in the field of medicine. It provides the radiation user with information needed to protect himself and others and to understand and comply with governmental and institutional regulations regarding the use of radionuclides and radiation machines. It is designed for a wide spectrum of users, including physicians, research scientists, engineers, and technicians. It should be useful also to radiation safety officers, members of radiation safety committees, and others who are responsible for the proper use of radiation sources, although they may not be working with the sources directly. The presentation in this manual is designed to obviate the need for reviews of atomic ...
Abstract Satellite measurements and numerical forecast model reanalysis data are used to compute an updated estimate of the cloud radiative effect on the global multi-annual mean radiative energy budget of the atmosphere and surface. The cloud radiative cooling effect through reflection of short wave radiation dominates over the long wave heating effect, resulting in a net cooling of the climate system of - 21 Wm-2. The short wave radiative effect of cloud is primarily manifest as a reduction in the solar radiation absorbed at the surface of - 53 Wm-2. Clouds impact long wave radiation by heating the moist tropical atmosphere (up to around 40 Wm-2 for global annual means) while enhancing the radiative cooling of the atmosphere over other regions, in particular higher latitudes and sub-trop...
The book examines current experimental and clinical knowledge concerning the biological and biophysical effects of electromagnetic radiation, particularly that in the microwave range. The biophysical bases of the interaction of electromagnetic radiation with matter are reviewed with emphasis on biological systems, and the effects of radiation on critical biological systems, including the nervous, reproductive, visual and blood-forming systems are compared. Data concerning the lethal effects of nonionizing radiation is presented and characteristics of the effects of electromagnetic radiation on the whole mammalian organisms are examined. Various reactions of the neuroendocrine system to electromagnetic radiation are described, with particular attention given to the adrenal system, and the combined effects of ionizing and microwave radiation ...
The biological age (BA) of the majority of the liquidators of the consequences of the radiation accidents in the Navy and of the liquidators of the Chernobyl' APS accident exceeds the medium standard and the DBA (due BA). The index of the BA can be a characteristic of the influence of the social-hygienic factors on the health condition of the Special Risk Subunit--the liquidators of the consequences of the radiation accidents. It was established, that the radiation influence concerns to the factors dramatically increasing the BA and the rate of senescence of the liquidators of the consequences of the radiation accidents. PMID:21809627
The experimental device for generation of undulator radiation in terahertz wavelength region by use of undulator with ferromagnets is created. The device is based on a beam of a microtron with the energy 7.5 MeV. The radiation wavelength is 200 mu. Registered spontaneous radiation has a power 10{sup -6} W at a current of a beam 2 mA in a pulse. With the optical resonator, in a mode, the amplification of 6% is received, that in sometimes is more than the expected value. This effect is explained as a result of partial coherence of radiation.
The emission of Cerenkov radiation by tachyons has been examined by using the reduced expansions of superluminal electromagnetic fields in terms of standard helicity representation of Poincare group. It has been shown that the tachyons emit Cerenkov radiation through their coupling only with subluminal electromagnetic fields and that a charged tachyon can emit Cerenkov radiation only in the media in which it travels with a velocity lower than that of light while in the usual medium in which its velocity is more than that of light, it will never emit Cerenkov radiation.
Characteristics of the Ukrainian NSA NRI radiation facility for scientific researches and developments of industrial radiation technology are performed. Parts of the facility, design peculiarities of technical tools are described. Biological protection of the facility and radiation protection system, transport line, systems of technical provision and radiation measurements are discussed
The radiation burden of the people of the GDR in relation to biomedical radiography altogether as well as organ doses, gonad doses and genetically significant doses in detail are outlined. The concepts of radiation protection and standards of radiographic examination are demonstrated. Possibilities of influencing radiation exposure by scientifically based indication of X-ray examination, application of new and improvement of usual examination techniques are discussed with regard to quality assurance and control. Proposals concerning the reduction of radiation exposure of the GDR population are presented.
High energy muon colliders, such as the TeV-scale conceptual designs now being considered, are found to produce enough high energy neutrinos to constitute a potentially serious off-site radiation hazard in the neighbourhood of the accelerator site. A general characterization of this radiation hazard is given, followed by an order-of-magnitude calculation for the off-site annual radiation dose and a discussion of accelerator design and site selection strategies to minimize the radiation hazard.
Correlation characteristics of quantum noise on the shadow radiation image (RI) of the object under nondestructive testing are studied. Mathematical model of RI occasional distortions is derived. The model takes into account the parameters of object under testing and of radiation beam by radiation quanta flux density. The results obtained can be used as a component in the process of investigation of various radiation testing systems
Coherent oscillator radiation is considered. A comparison is made with classical particle radiation with gauss distribution. Decay probability for coherent state in spontaneous radiation is estimated. The method suggested for describing harmonic oscillator allows to separate the effect of classical field radiation from quantum description of particle state within the framework of a self-consistent quantum mechanical problem.
Pentaerythritol tetranitrate (PETN) is a relatively sensitive explosive used in many electroexplosive devices as well as in medicine. Of primary interest to LLNL is its use in items such as exploding bridgewire (EBW) detonators and exploding bridge foil initiators (EFI). In these devices the crystalline powder is pressed into a granular, low-density compact that can be initiated by an exploding wire or foil. The long-term stability of this pressed compact is of interest to weapon stockpile lifetime prediction studies. Key points about potential aging mechanisms can be summarized as follows: (1) There are a number of factors that can contribute to PETN instability. These include particle size, polymorphic phase transitions, crystal structure, impurities, moisture, occlusions, chemical incompatibility and biological (microorganism) action. of these factors the most important for long-term aging of high surface area powders used in detonators appears to be that of particle size growth. ...
A new type of radiation which occurs when particles are accelerated in the field of a longitudinal wave and in a transverse magnetic field is studied. The characteristics of such spontaneous radiation are obtained, and the influence of collective effects on the radiation is analyzed. The application of the findings to the theory of free electron lasers is discussed. 8 references.
Objectives To provide direct estimates of risk of cancer after protracted low doses of ionising radiation and to strengthen the scientific basis of radiation protection standards for environmental,...Full Text Available
Forty-four patients with histologically proven Hodgkin's disease underwent initial treatment with extended-field radiation therapy. Nineteen of these patients also received combination chemotherapy....Full Text Available
Exact anatomic knowledge about the location of the gonads and the application of corresponding measures of radiation protection are the preconditions for an efficient reduction of the danger of a possible genetic damage as a result of radiation exposition during X-ray examination of the hip joint of newborns. (VJ).
Adaptive radiation therapy (ART) is the incorporation of daily images in the radiotherapy treatment process so that the treatment plan can be evaluated and modified to maximize the amount of radiation...Full Text Available
Analytical method of theoretical simulation of collective hydrodynamic instabilities of intensive flows of discrete radiators, interacting with each other only through the coherent fields of their spontaneous radiation in corresponding media was suggested...
... Top of page Testing Radiation coming from granite countertops results from natural radioactive material in the granite. Identifying the presence and concentration of radioactive elements in granite requires expensive and sophisticated portable instruments or laboratory equipment. These instruments and equipment require proper calibration, and interpretation of ...
The different radiation loads caused by natural and artificial radionuclides are compared in this paper. This examples will serve to illustrate that the problem of population exposure to radiation can only be solved in consideration of all components and to show which effects of the radiation from natural sources are of special importance in this connexion. (orig./AK).
The problem of optimizing a horn radiator of electromagnetic waves for the reflection coefficient and the coefficient of transformation of the fundamental mode into higher order modes is solved. Optimization is performed by means of selecting a combined shape of the radiator generatrices.
The inhibitor action of unbranched polyamines on corrosion of low-carbon steel in 0.5 M sulfuric acid is studied through potentiostatic polarization curves. It is shown that the inhibitor efficiency I depends on the polyamine concentration and molecular structure. The quantum-mechanical calculations of molecular properties are accomplished through the MNDO method. Correlation between the measured I and physicochemical properties of the polyamine inhibitors in protonized and nonprotonized form is found with application of the general perturbation theory
...) Abstract: Fluorescence microscopic imaging is widely used in biomedical research to study molecular and cellular processes in cell culture or tissue samples. This is motivated by the high inherent sensitivity of fluorescence techniques, the spatial resolution that compares favorably with cellular dimensions, the stability of the fluorescent labels used and the sophisticated strategies that have been developed for selectively labeling target molecules. More recently, two and ...
Peroxisome proliferator activated receptor-{gamma} (PPAR{gamma}) regulates metabolic homeostasis and adipocyte differentiation, and it is activated by oxidized and nitrated fatty acids. Here we report the crystal structure of the PPAR{gamma} ligand binding domain bound to nitrated linoleic acid, a potent endogenous ligand of PPAR{gamma}. Structural and functional studies of receptor-ligand interactions reveal the molecular basis of PPAR{gamma} discrimination of various naturally occurring fatty acid derivatives.
We develop a theory of Smectic A - Smectic C phase transition with anomalously weak smectic layer contraction. We construct a phenomenological description of this transition by generalizing the Chen-Lubensky model. Using a mean-field molecular model, we demonstrate that a relatively simple interaction potential suffices to describe the transition. The theoretical results are in excellent agreement with experimental data.
Chapter 5, describes some of the most important molecular methods used in the study of chromosome structure and function. The methods discussed include fragmentation of DNA, cloning, flow cytometry and chromosome sorting, is situ hybridization, polymerase chain reaction (PCR), and yeast artificial chromosomes (YACs). 18 refs., 3 figs., 1 tab.
Molecular dynamics computer simulations of a dense nanocrystalline Nickel sample are performed on the parallel Cray T3 (EPFL-Lausanne). The sample contains 50 grains with an average size of 3 nm. By perturbing the relaxed configuration elastic and plastic properties are studied. (author) 1 fig., 1 ref.
The objective of this project is the development of a new class of metalloporphyrin materials used as catalsyts for use in fuel cell applications. The metalloporphyrins are excellent candidates for use as catalysts at both the anode and cathode. The catalysts reduce oxygen in 1 M potassium hydroxide, as well as in 2 M sulfuric acid. Covalent attachment to carbon supports is being investigated. The computer-aided molecular design is an iterative process, in which experimental results feed back into the design of future catalysts.
Stabilized silver particles comprise particles comprising silver, a short-chain capping agent adsorbed on the particles, and a long-chain capping agent adsorbed on the particles. The short-chain capping agent is a first anionic polyelectrolyte having a molecular weight (Mw) of at most 10,000, and the long-chain capping agent is a second anionic polyelectrolyte having a molecular weight (Mw) of at least 25,000. The stabilized silver particles have a solid loading of metallic silver of at least 50 wt %.
Most chemical reactions in industry and biology are catalytic and play a role at some stage of the processing of about 80% of the goods manufactured in the U.S., yet catalysis is a neglected subject in chemical education. This book integrates the fragmentary treatment accorded the topic until now. It covers, in a unified way, catalysis in solutions, by enzymes, in synthetic polymers within the molecular scale cages of zeolites and other molecular sieves, and on surfaces of inorganic solids. The central ideas are chemical; and principles are illustrated by emphasizing industrial reactions and catalysts.
In ab initio molecular dynamics, whenever information about the potential energy surface is needed for integrating the equations of motion, it is computed 'on the fly' using electronic structure calculations. For Born-Oppenheimer methods, the electronic structure calculations are converged, whereas in the extended Lagrangian approach the electronic structure is propagated along with the nuclei. Some recent advances for both approaches are discussed.
The Gordon Research Conference (GRC) on 2004 Gordon Research Conference on Reversible Associations in Structure & Molecular Biology was held at Four Points Sheraton, CA, 1/25-30/2004. The Conference was well attended with 82 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students.
An optical klystron is built in the 800 MeV electron storage ring at University of Science and Technology of China for harmonic super-radiation generation. In single bunch operation mode the repetition rate of the spontaneous radiation pulses is about 4.533 MHz, and the repetition rate of the seed laser pulses is about 3 Hz, while the radiation pulse duration is 300 ps. For measuring harmonic radiation a high on/off ratio ICCD is used as an optical switch to reject spontaneous radiation pulses of high repetition rate
The document published under A/63:46 and titled report of the scientific committee of United Nations for the study of ionizing radiations effects, gives the situation of the fifty sixth session of the committee that stood at Vienna from the 10. to 18. july 2008. In the chapter 3 of this report the writers summarize the strategic planning and the working program of the scientific committee for the period 2009-2013. They note that the committee worry about the inadequate means, particularly in personnel. The priorities for the given period will be the medical exposure of patients, the radiation levels and the effects of energy production, the exposure to natural radiation sources and the improvement of the understanding of the effects of the low doses radiation exposure. (N.C.)
We have used the SINFONI integral field spectrograph to map the near-infrared K-band emission lines of molecular and ionised hydrogen in the central regions of two cool core galaxy clusters, Abell 2597 and Sersic 159-03. Gas is detected out to 20 kpc from the nuclei of the brightest cluster galaxies and found to be distributed in clumps and filaments around it. The ionised and molecular gas phases trace each other closely in extent and dynamical state. Both gas phases show signs of interaction with the active nucleus. Within the nuclear regions the kinetic luminosity of this gas is found to be somewhat smaller than the current radio luminosity. Outside the nuclear region the gas has a low velocity dispersion and shows smooth velocity gradients. There is no strong correlation between the intensity of the molecular and ionised gas emission and either the radio or X-ray emission. The molecular gas in Abell ...
In mammals and insects, paracellular blood barriers isolate the nervous system from the rest of the animal. Glia and accessory cells of the nervous system use pumps, channels, cotransporters, and exchangers collectively to maintain the extracellular ion environment and osmotic balance in the nervous system. At present, the molecular mechanisms that regulate this process remain unclear. In humans, loss of extracellular ion and volume regulation in the nervous system poses serious health threats. Drosophila is a model genetic organism with a proven track record for uncovering molecular mechanisms relevant to human health and disease. Here, we review what is known about extracellular ion and volume regulation in larval abdominal nerves, present some new data about the impact of neural activity on the extracellular environment, and relate the findings to mammalian systems. Homologies have been found at the level of morphology, physiology, ...
Nov 8, 2010 ... Ihring Mission 11, the radiation dosimetry measurement system functioned normally and provided data on the Earth's trapped radiation belts ...
Selection of the appropriate radiation quality is an important aspect of optimisation for every clinical imaging task in radiology, since it affects both image quality and patient dose. Spreadsheet...Full Text Available
By proposing the four-dimensional, reciprocity transformations the appropriate condition for superluminal electromagnetic Cerenkov radiation is obtained by introducing the hypothesis that tachyons possess vector energy and scalar momentum.
drical Enclosures Using a Numerical Ray Tracing Technique. NASA. TM-I02527, 1990 . Buckley, H.: Radiation from the Interior of a Reflecting Cylinder. Philos. ...
...References | Radiation Protection | US EPA This page provides links to the reference material on EPA's Radiation Protection Web site. U.S. EPA/...OAR/ORIA/Radiation Protection Division Jump to main content. Radiation Protection Contact Us Search: All EPA This Area You are here: EPA Home ... Radiation Protection References PageName Technical Users General Public Reporters Librarians Students/Teachers PROGRAMS TOPICS REFERENCES References The Reference Section provides general material that support the ...other sections of EPA's Radiation Protection Web site. You will find links within the information to related pages throughout the Radiation Protection , EPA ...
The fundamental product of tetracycline hydrochlorine gamma radiolysis was separated in its solid state. From the results of spectroscopic studies it has been established that it is des-N,N-dimethylaminotetracycline.
Turbulent premixed methane-air combustion in a cylindrical chamber is numerically simulated considering radiation effect. Reaction rates are considered as minimum rates between Arrhenius rates and eddy break up rates. A five step reduced mechanism is used. Turbulent modeling is done via standard k-{epsilon} model imposed by empirical inlet boundary conditions. Source terms of energy equation consist of reaction rates and radiation effects. The discrete ordinate method (DOM) is employed to solve the radiative transfer equation (RTE) and the weighted sum of gray gas model (WSGGM) is imposed to consider radiation effect of non-gray gases. The results indicate that in the case of turbulent combusting flows, the effect of radiation of gases can affect the temperature and species concentrations. The numerical results obtained considering radiation effect are closer to ...
Turbulent premixed methane-air combustion in a cylindrical chamber is numerically simulated considering radiation effect. Reaction rates are considered as minimum rates between Arrhenius rates and eddy break up rates. A five step reduced mechanism is used. Turbulent modeling is done via standard k-? model imposed by empirical inlet boundary conditions. Source terms of energy equation consist of reaction rates and radiation effects. The discrete ordinate method (DOM) is employed to solve the radiative transfer equation (RTE) and the weighted sum of gray gas model (WSGGM) is imposed to consider radiation effect of non-gray gases. The results indicate that in the case of turbulent combusting flows, the effect of radiation of gases can affect the temperature and species concentrations. The numerical results obtained considering radiation effect are closer to the ...
... iFfficiency-en- enhanced spontaneous radiation at the free-electron- ... as enhanced spontaneous radiation at the free-electron-laser wavelength. ...
The introduction of tolerance to radiation (''radiation-hardness'') into large electronic systems is one of the major tasks to which this Handbook will be put. The practices recommended here for inculcating radiation-tolerance in equipment require advanced physical modeling techniques, precise engineering procedures, and firm assurance procedures. The degree to which these procedures should be used in an equipment project can be measured by the severity of the raw radiation environment, the desired reliability of the system, and the requirement of that project for radiation-sensitive technologies. The balance of device/circuit design versus shielding will depend on whether the radiation is highly penetrating -- as in isotope handling or military environments -- or readily attenuated, as in space. In this chapter the authors have attempted to summarize the ...
When energetic bunches of electrons traverse an undulator field, they can spontaneously emit radiation both coherently and incoherently. Although it has generally been assumed that undulator radiation is incoherent at wavelengths short compared to the longitudinal size of the electron bunch, several recent observations have proved this assumption false. Furthermore, the appearance of coherent radiation is often accompanied by a significant increase in radiated power. Here we report observations of strongly enhanced coherent spontaneous radiation together with direct measurements, using transition radiation techniques, of the electron distributions responsible for the coherent emission. We also report demonstrated enhancements in the predicted spontaneous radiated power by as much as 6x10"4 using electron bunch compression. copyright 1996 ...
... Except for isolated radiation accidents over the ensuing years, little practical experience has been gained in the treatment of thermal injuries ...
... spontaneous radiation of amplifiers within a relatively w~de range of ... pulse widths are 20-30ns, while amplified spontaneous radiation pulse ...
A formalism for the dynamical treatment of the molecular orbitals of valence nucleons in nucleus-nucleus collisions is developed with the use of the coupled-reaction-channel (CRC) method. The Coriolis coupling effects as well as the finite mass effects of the nucleon are taken into account in this model, of rotating molecular orbitals, RMO. First, the validity of the concept is examined from the viewpoint of the multi-step processes in a standard CRC calculation for systems containing two identical [core] nuclei. The calculations show strong CRC effects particularly in the case where the mixing of different l-parity orbitals - called hybridization in atomic physics - occurs. Then, the RMO representation for active nucleons is applied to the same systems and compared to the CRC results. Its validity is investigated with respect to the radial motion (adiabaticity) and the rotation of the molecular axis (radial and rotational ...
The book is divided into two approximately equal parts. The first four chapters are relatively lengthy and cover the basic principles of radiation biology, carcinogenesis and therapy, along with a brief introduction to radiological physics to orient the reader without background in this specialized related discipline. The remainder consists of twenty-four relatively brief chapters, each covering the radiation biology of a specific organ, tissue, or systems tissues, with emphasis on the tumorigenic and tumoricidal action of ionizing radiations.
The present state of knowledge on the influence of stray radiation on image quality and its physical description and quantification is summarized. Experimental results on the influence of physical parameters on the fraction of scattered radiation and the effect of scatter reduction by air gap technique and secondary radiation grids are committed. Open theoretical and practical problems and the limitations of common methods of scatter reduction are pointed out. (author).
Disclosed herein is a radiation detector providing for the in situ automatic sampling of fluids containing substances emitting radiation, especially Cerenkov radiation. The detector permits sampling within well casings and is self-purging such that no additional provisions must be established for the storage and disposal of contaminated fluids.
A study is made of the mechanical properties of vanadium irradiated with fast neutrons up to dose 8.6.10"-"4 dpa, as a function of the temperature of post-radiation annealing. The radiation-annealing hardening (RAH) effect is observed at 300"oC, in agreement with previous studies. It is established for the first time that RAH is accompanied by fall in ductility. A phenomenological model is described which explains the dependence of RAH on radiation dose and temperature, as well as on the content of chemically active alloying impurities. (author).
A multi-spectral Schottky barrier infrared detector array in which individual pixels of radiation from a remote radiating object are detected by two or more Schottky barrier infrared radiation detectors each having a different spectral response so as to provide a ''color'' discrimination for the array.
A multi-spectral Schottky barrier infrared detector array in which individual pixels of radiation from a remote radiating object are detected by two or more Schottky barrier infrared radiation detectors each having a different spectral response so as to provide a ''color'' discrimination for the array.
A formula is obtained which describes the kinetics of low-temperature radiation hardening caused by creation of dislocation loops of interstitial type during irradiation. The radiation hardening of aluminum and vanadium is estimated using this formula and results of experiments on studying processes of nucleation and growth of interstitial dislocation loops in these materials by transparent electron microscopy. It is shown that the proposed formula is valid for description of the kinetics of low-temperature radiation hardening.
In scattering of channeled particles by point defects and in emission of gamma rays in the spontaneous-radiation spectral region conditions are attained where the momentum transferred to the defect is taken up by the crystal as a whole. This leads to coherent and interference effects in the radiation from the crystal defects. When the longitudinal momentum transferred is zero, an induced radiation effect appears in the transitions between the states of transverse motion.
External radiation dose exceeded 5,000 rad in three cases, and intravaginal radiation dose was 5,000 rad in one case. Radiation damage including perforation was seen in the end of ileus in one case, in the sigmoid and rectum in two cases, and in the end of ileus, sigmoid and rectum in the last case. Satisfactory results were obtained by the removal of the ileocecum in the case of the damage in the end of the ileus. However, only colostomy was performed for the damage in the sigmoid and rectum.
Due to the intensity and vast number of subjects, this Bremen experts' discussion, too, could discuss only part of the problem of the possibilitiy to quantify the radiation hazard. One preliminary result is that there is no scientific proof of the harmlessness of radiation exposure during normal operation of a nuclear power plant, either within the plant or in its vicinity. Other results are that some important questions can not be answered yet, and that there are important hints on the dangers even of low radiation doses. (GL).
In 1998, research began at Idaho National Engineering and Environmental Laboratory to investigate the application of {sup 6}Li and {sup 7}Li isotopes to the measurement of neutron and gamma radiation. Various size pairs of {sup 6}Li and {sup 7}Li based detectors were exposed to mixed neutron and gamma radiation. Experiments demonstrated that these detectors could be used to measure low level neutron radiation in the presence of high level gamma radiation. (author)
In 1998, research began at Idaho National Engineering and Environmental Laboratory to investigate the application of "6Li and "7Li isotopes to the measurement of neutron and gamma radiation. Various size pairs of "6Li and "7Li based detectors were exposed to mixed neutron and gamma radiation. Experiments demonstrated that these detectors could be used to measure low level neutron radiation in the presence of high level gamma radiation. (author)
The total radiation rate, angular distribution of the emitted energy and photon correlations of the cooperative spontaneous radiation from two atoms with different resonance frequencies and spontaneous decay rates are calculated. Contrary to the case of two identical atoms oscillations appear in the total radiation rate and the spatial distribution of the total number of emitted photons differs from the single-atom radiation pattern. The effect of the dipole-dipole near-field interaction on the time evolution of the atomic system is discussed. (author).
BackgroundTo compare two strategies of dynamic intensity modulated radiation therapy (dIMRT) with 3-dimensional conformal radiation therapy (3DCRT) in the setting of hypofractionated...Full Text Available
Results on defect structure study and degree of molybdenum radiation hardening irradiated by fission neutrons and medium energy alpha-particles are presented. It is shown that molybdenum irradiation by alpha-particles and neutrons leads to different degree of material hardening for the same damage level. It is established that molybdenum radiation hardening is mainly defined by radiation defect clusters visible in electron microscope whose coefficient of rigidity depends on their size. 5 refs.; 6 figs.; 2 tabs. (author).
We formulate a complete theory of Edge Radiation based on a novel method relying on Fourier Optics techniques. Similar types of radiation like Transition Undulator Radiation are addressed in the framework of the same formalism. Special attention is payed in discussing the validity of approximations upon which the theory is built. Our study makes consistent use of both similarity techniques and comparisons with numerical results from simulation. We discuss both near and far zone. Physical understanding of many asymptotes is discussed. Based on the solution of the field equation with a tensor Green's function technique, we also discuss an analytical model to describe the presence of a vacuum chamber. In particular, explicit calculations for a circular vacuum chamber are reported. Finally, we consider the use of Edge Radiation as a tool for electron beam diagnostics. We discuss Coherent Edge ...
The influence of a periodic electromagnetic field on the radiative corrections to the atomic energy levels is studied for the case of ''strong fields'' for which the interaction between the atom and field is of the order or greater than the radiative effects. The analysis is carried out on the basis of the Schwinger-Dirac equation for the propagation function of a bound electron in the field and on the basis of the density matrix in the Furry representation. It is shown that in the strong field approximation the radiative shifts and widths are manifest as radiative corrections to the quasi-energies. In super-high resolution experiments intensity effects in the radiative corrections to the atomic levels are obtained in the case of single-photon resonance. Some multiphoton processes are condidered by taking into account the effect of the field on ...
The stages of processes leading to radiation damage are studied, as well as, the direct and indirect mechanics of its production. The radiation effects on nucleic acid and protein macro moleculas are treated. The physical and chemical factors that modify radiosensibility are analysed, in particular the oxygen effects, the sensibilization by analogues of nitrogen bases, post-effects, chemical protection and inherent cell factors. Consideration is given to restoration processes by excision of injured fragments, the bloching of the excision restoration processes, the restoration of lesions caused by ionizing radiations and to the restoration by genetic recombination. Referring to somatic effects of radiation, the early ones and the acute syndrome of radiation are discussed. The difference of radiosensibility observed in mammalian cells and main observable alterations in tissues and ...
The optically stimulated luminescent (OSL) radiation dosimeter technically surveys a wide dynamic measurement range and a high sensitivity. Optical fiber dosimeters provide capability for remote monitoring of the radiation in the locations which are difficult-to-access and hazardous. In addition, optical fiber dosimeters are immune to electrical and radio-frequency interference. In this paper, a novel remote optical fiber radiation dosimeter is described. The optical fiber dosimeter takes advantage of the charge trapping materials CaS:Ce, Sm that exhibit OSL. The measuring range of the dosimeter is from 0.1 to 100 Gy. The equipment is relatively simple and small in size, and has low power consumption. This device is suitable for measuring the space radiation dose and also can be used in high radiation dose condition and other dangerous radiation occasions. ...
A series of novel triazolinones were synthesized and their structures were characterized by 1H NMR, elemental analysis and single-crystal X-ray diffraction analysis. The herbicidal activities were evaluated against Echinochloa crusgalli (L.) Beauv., Digitaria adscendens, Brassica napus and Amaranthus retroflexus. The herbicidal activity data indicated that the title compounds had higher activities with substituted benzyl group moieties than with other groups such as sulfonyl, alkyl, etc. To further investigate the structure-activity relationship, comparative molecular field analysis was performed on the basis of herbicidal activity data. Both the steric and electronic field distributions of comparative molecular field analysis are in good agreement in this work. The results showed that a b...
Globodera rostochiensis and Globodera pallida are parasitic root cyst nematodes of potato (PCN), which significantly reduce yield and quality. The genetics and available molecular markers should make resistance to nematodes an excellent candidate for marker assisted selection. The study presents results of testing the suitability of known molecular markers for detection of resistance in a set of cultivars. We revealed some inconsistencies in genealogical data of the cultivars and showed inconsistent usefulness in detecting resistant cultivars. The marker TG689 was identified in almost all cultivars resistant to G. rostochiensis and together with other markers was used for verifying the resistance in a group of breeding lines. The marker TG689 was the most effective. However, the efficiency...
The first year of this effort was focussed on the following broad objectives: (1) Analyze the molecular types present in shale oil (as a function of molecular weight distribution); (2) Determine the behavior of these molecular types in liquid-liquid extraction; (3) Develop the analytical tools needed to systematize the process development; (4) Survey the markets to assure that these have high value uses for the types found in shale oil; (5) Explore selective process means for extracting/converting shale oil components into concentrates of potentially marketable components; (6) Compile overview of the venture development strategy and begin implementation of that strategy. Each of these tasks has been completed in sufficient detail that we can now focus on filling in the knowledge gaps evident from the overview.
This contribution is an informal essay based on a talk delivered at the Institute for Mathematics and its Applications (IMA) in Minneapolis, under the summer program in molecular biology, July 18-22, 1994. I exclude many technical details, which can be found elsewhere, and instead focus on the basic ideas of molecular dynamics simulations, with the goal of conveying to students and non-specialists the key concepts of the theory and practice of large-scale simulations. Following a description of the basic idea in molecular dynamics, I discuss some of the practical details involved in simulations of large biological molecules, the numerical timestep problem, and approaches to this problem based on implicit-integration techniques. I end with a perspective of open challenges in the field and directions for future research. 79 refs., 6 figs., 1 tab.
Abstract The electrochemical properties of a perfluorosulfonic acid (PFSA) membrane are estimated using a combination of molecular dynamics simulation and statistical thermodynamic model. We obtain all parameters in an ionic conductivity model from an atomistic simulation and remove all adjusted model parameters. From a microscopic point of view, the hydrated PFSA membrane shows micro-phase segregation which separated into hydrophilic and hydrophobic phases. Our present work originates with this phenomenon and we treat this phase segregation as if it is a continuous phase for each of which the proton (H+) is transported inside the PFSA membrane/solvent (water and alcohols) mixture. The chemical potential for a given system is estimated using a molecular simulation technique to predict the ...
Abstract The air-water interface presents several interesting features, namely a) a molecularly flat environment, b) a boundary region between two phases with different dielectric constants, c) permits or promotes dynamic interactions within the interface region, and d) a point of interaction between hydrophobic compounds and aqueous molecules. Accordingly, Langmuir monolayers at the air-water interface have several unique characteristics and properties, which require investigation. In this review-type personal account, typical examples of molecular recognition and molecular patterning at air-water interfaces are first introduced, followed by descriptions of specific and unusual properties of monolayers on water. In addition, two examples of our own results concerning Langmuir monolayers a...
This paper reviews the molecular biology of the renin-angiotensin system. The renin gene structure is analyzed in detail, including an examination of the putative regulatory regions. The combined action of these regulatory sequences would result in the complex, tissue-specific expression and regulation observed in vivo. The expression of the tissue renin-angiotensin systems, which may have important physiological functions, is also described. In addition, the pathway of renin biosynthesis and secretion is reviewed. This includes speculation on the fate of circulating prorenin and the physiological role of multiple renin forms and secretory pathways. The molecular approaches described in this paper have greatly advanced our knowledge of the biology of the renin-angiotensin system. Future studies using these and other approaches should provide further insight into this complex system.
substrate). Within each group of simulations, three lubricant film thicknesses are studied to examine the effect of varying lubricant thickness. Statistical data are collected from each simulation and presented in this work. Via these data, together with the evolution, of atomic and molecular configurations, a very detailed picture of the properties of this thin film interface is presented. In particular, we conclude that perfluoropolyether lubricant forms distinct molecular layers when confined between two substrates, the rate of heat generation under shearing conditions typical of those in a head-disk interface is insufficient for thermal mechanisms to result directly in lubricant degradation, and mechanical stresses attained in the head-disk interface are unlikely to result in any significant degree of lubricant degradation. This thesis examines the tribology of a head-disk interface in an operating hard disk drive via non-equilibrium ...
The interfaces between metal electrodes and electroactive organic materials are important for the performance of organic electronic devices. One way of optimizing the anode/organic interface is the insertion of a (sub-)monolayer of molecular acceptors. Here we present an UPS study of new electron acceptor molecules deposited on Au(111), Cu(111) and Ag(111). This study intends to improve the understanding of how the interactions of specific electron withdrawing groups with metal surfaces are correlated with observed modifications of interfacial electron density distribution, work function change ({delta}{phi}), and the energy level alignment. We find that {delta}{phi}, which is the difference between the work function ({phi}) of the clean metal surface and {phi} after formation of a molecular monolayer, is a monotonic function of initial {phi} of the metal. Two different slopes were observed for acceptors with cyano and those with keto or nitro ...
The results of following the oxidative degradation of a plastic-bonded explosive (PBX 9501) are reported. Into over 1100 sealed containers were placed samples of PBX 9501 and combinations of its components and aged at relatively low temperatures to induce oxidative degradation of the samples. One of the components of the explosive is a poly(ester urethane) polymer and the oxidative degradation of the samples were following by measuring the molecular weight change of the polymer by gel permeation chromatography (coupled with both differential refractive index and multiangle laser light scattering detectors). Multiple temperatures between 40 and 64 degreeC were used to accelerate the aging of the samples. Interesting induction period behavior, along with both molecular weight increasing (cro...
The antisymmetric many-body trial state which describes a system of interacting fermions is parametrized in terms of localized wave packets. The equations of motion are derived from the time-dependent quantum variational principle. The resulting fermionic molecular dynamics (FMD) equations include a wide range of semi-quantal to classical physics extending from deformed Hartree-Fock theory to newtonian molecular dynamics. Conservation laws are discussed in connection with the choice of the trial state. The model is applied to heavy-ion collisions with which its basic features are illustrated. The results show a great variety of phenomena including deeply inelastic collisions, fusion, incomplete fusion, fragmentation, neck emission, promptly emitted nucleons and evaporation. ((orig.)).
High molecular weight products of the ozonolysis reaction of particle-phase 9-octadecenoic acid (oleic acid) have been studied by photoelectron resonance capture ionization (PERCI) mass spectrometry (MS). Oleic acid particles ( Formula Not Shown , Formula Not Shown ) were reacted with ozone (1.8x10-4atm) in a flow reactor at reaction times of 8 and 23s. Particles were sampled on-line with a differentially pumped particle inlet and chemically analyzed by PERCI-MS. PERCI is a soft ionization method that permits the direct measurement of relatively high molecular weight compounds, facilitating molecular identification. In addition to cyclic oxygenates, such as secondary ozonides and geminal diperoxides that were reported previously, we demonstrate the formation of polymers at the particle sur...
The thermodynamic characteristics of adsorption of iodobenzene, 2-iodothiophene, and 1- and 2-iodoadamantanes on the surface of graphitized thermal carbon black were determined experimentally. The influence of the special features of the molecular structure of the adsorbates on the thermodynamic characteristics of adsorption was studied. The atom-atom approximation of the semiempirical molecular-statistical theory of adsorption was used to calculate the thermodynamic characteristics of adsorption of the adsorbates using the newly determined potential function parameters of pair intermolecular interaction (?( r)) of I with C atoms of the basal graphite face. For the example of isostructural monohalogenated benzenes, thiophenes, and adamantanes, a comparative analysis of the contributions of the F, Cl, Br, and I atoms to the thermodynamic characteristics of adsorption was performed for the nonspecific adsorption of these compounds on a plane ...
Orientational constraints obtained from solid state NMR experiments on anisotropic samples are used here in molecular dynamics (MD) simulations for determining the structure and dynamics of several different membrane-bound molecules. The new MD technique is based on the inclusion of orientation dependent pseudo-forces in the COSMOS-NMR force field. These forces drive molecular rotations and re-orientations in the simulation, such that the motional time-averages of the tensorial NMR properties approach the experimentally measured parameters. The orientational-constraint-driven MD simulations are universally applicable to all NMR interaction tensors, such as chemical shifts, dipolar couplings and quadrupolar interactions. The strategy does not depend on the initial choice of coordinates, and...
Hydrogen molecule adsorption on the (0001) surface of double hexagonal closed packed americium has been studied in detail within the framework of density functional theory. Weak molecular hydrogen adsorptions were observed. The most stable configuration corresponded to a Hor2 approach molecular adsorption at the one-fold top site where the molecule's approach is perpendicular to a lattice vector. Adsorption energies and adsorption geometries for different adsorption sites will be discussed. The change in work functions, magnetic moments, partial charges inside muffin-tins, difference charge density distributions and density of states for the bare Am slab and the Am slab after adsorption of the hydrogen molecule will be discussed. Reaction barrier for the dissociation of hydrogen molecule will be presented. The implications of adsorption on Am 5f electron localization-delocalization will be summarized.
This paper shows how molecular theory paves the way for accelerated aging tests of safety-related equipment in nuclear power plants, as required by NRC qualification programs. Arrhenius' model, based on an equation, provides useful information regarding the extent of molecular change as a function of time and temperature. Critical to determining the aging characteristics and qualified life of organic materials is the activation energy concept, which is derived from information gathered when the molecular reaction of the material is documented over the entire life cycle. In accelerated-aging applications, the importance of the model lies in characterizing the chemical related reactions of materials. The problem with the Arrhenius approach is that, in generating a testing period of reasonable duration, a rather high test temperature must be selected which may lead to an added and unrelated environmental effect.
The atomic explosions in Hiroshima and Nagasaki made the name radiation itself become a nightmare. Notwithstanding this, radiation continued to serve the mankind specially in diagnosis of several human diseases and in the treatment of intractable malignancies. With their latest research tools biologists have now shown a significant shift in the earlier paradigm; even the concept that radiation initiates cancer appears to be no longer tenable. On the contrary, selective radiation doses inhibit growth of cancer cells and radiation in combination with many chemotherapeutic drugs, radiosensitizing chemicals and/or hyperthermia, is emerging as a new modality for cancer treatment which offers high therapeutic advantages. In addition, the deleterious effects of radiation can now be strategically counter poised by the use of many drugs and chemicals. This has been ...
Scattered radiation generated in patient and imaging system has to be considered when quality-assurance tests involve dose detection or image-quality estimations. Measurement of automatic-exposure control dose can be altered by backscattering from intensifying screens of more than 10% and the equipment transmission factor can be overestimated up to a factor of 10 when only primary radiation is used. The sensitivity of intensifying screens depends on the angle of incidence of the radiation and so primary and scattered radiation are detected differently. The quality-control aspects of anti-scatter grids are discussed. (author).
Scattered radiation generated in patient and imaging system has to be considered when quality-assurance tests involve dose detection or image-quality estimations. Measurement of automatic-exposure control dose can be altered by backscattering from intensifying screens of more than 10% and the equipment transmission factor can be overestimated up to a factor of 10 when only primary radiation is used. The sensitivity of intensifying screens depends on the angle of incidence of the radiation and so primary and scattered radiation are detected differently. The quality-control aspects of anti-scatter grids are discussed. (author).
The emission of Cerenkov radiation by tachyons has been examined by using the reduced expansions of superluminal electromagnetic fields in terms of standard helicity representation of Poincare group. It has been shown that the tachyons emit Cerenkov radiation through their coupling only with subluminal electromagnetic fields and that a charged tachyon can emit Cerenkov radiation only in the media in which it travels with a velocity lower than that of light while in the usual medium in which its velocity is more than that of light, it will never emit Cerenkov radiation. (author).
Standard radiation monitoring has been conducted at Sendai nuclear power station for the purpose of estimation of 'source activity' during refueling outage and evaluation of countermeasures to reduce dose rate. Selected objects of the monitoring are radiation dose rate at maintenance area, radiation field at each equipment and piping, coolant chemistry and plant operation condition. Monitored data indicates that 'source activity' variation can be estimated to some extent using influential factors, and that evaluation of change of loose crud activity, which is presumed to be represented by the dose rate at letdown heat exchanger, is necessary to further explain change in radiation field at main work area. (author).
The authors give a survey of the somatic radiation risk in X-ray diagnostics. A somatic dose index is calculated for different examination methods containing the organ doses to the red bone marrow, the lung, the female breast, and the thyroid gland and evaluating their somatic significance. If this somatic dose index by which the individual radiation risk is described, is multiplied by the examination frequencies per year in the German Federal Republic, one gets the somatically significant dose index, which is a measure of the collective somatic radiation risk. In this sense, mammography has the highest, and dental radiography the lowest collective radiation risk.
The authors give a survey of the somatic radiation ris in X-ray diagnostics. A somatic dose index is calculated for different examination methods containing the organ doses to the red bone marrow, the lung, the female breast, and the thyroid gland and evaluating their somatic significance. If this somatic dose index by which the individual radiation risk is described, is multiplied by the examination frequencies per year in the German Federal Republic, one gets the somatically significant dose index, which is a measure of the collective somatic radiation risk. In this sense, mammography has the highest, and dental radiography the lowest collective radiation risk. (orig.).
The diffusion coefficient of particles in radioactive gases has been calculated with account of random wandering of aerosols (occurrence of local fields affecting the particles; recoils accompanying radiation emitted by particles, etc.). To determine the diffusion coefficient, the method of Fokker-Planck equation derivation was used. A formula is presented for calculating the radiation-stimulated diffusion coefficient. A linear growth of the diffusion coefficient with radioactivity is noted according to the formula, the diffusion coefficient is mainly determined by the field in the radiation damage region. The aerosol radioactivity may result in a more rapid deposition of aerosols in the pipelines and aerosol purification systems. The diffusion rate grows not only in the presence of intrinsic radioactivity but in case of external radiation exposure as well.
The results of theoretical and experimental investigations, describing the effect of ionizing radiation on wood and its main components and methods for production of wood-plastic composites by means of radiation-induced chemical modification are generalized. Domestic and foreign experience in their production is systematized; physico-mechanical characteristics of new material, simulation and calculation of irradiating devices, as well as calculation and experimental study of #gamma#-radiation attenuation both by wood material and by wood of different species are given. Gamma sources ("6"0Co isotope, a hot loop of a nuclear reactor) as well as electron accelerators are considered as ionizing radiation sources.
RADSOLVER is a computer program which calculates the radiation energy transport in cavity type receivers having an arbitrary number of apertures through which collimated beams of solar radiation enter. In contrast to the common assumption of gray (or semi-gray) surfaces used in the modeling of radiation transport, RADSOLVER accounts for the wavelength-dependence of emission, absorption and reflection with a band model of the radiative properties. It is intended that this report serve both as an instruction manual for the use of the RADSOLVER code and a vehicle for presenting the underlying theory. Illustrative examples along with input and output are presented.
Outage is a specific period of time for radiation protection in a nuclear power plant, in which the radiation risk and collective dose are both at the highest level. In this article, the practice and experience of occupational exposure control in the outages of Daya Bay Nuclear Power Plant are introduced through following aspects: early involvement in outage preparation by radiation protection service, control of source term, radiation protection and safety management in the outage implementation processes, the effectiveness of the plant's safety management network and overall involvement of all staffs of the plant, experience feedback and continuous improvement in radiation protection management, etc
In radiation risk assessment it must be differentiated between somatic and genetic effect on the one hand as well as between stochastic and non-stochastic effect on the other. According to definitions of the ICRP report 26 the limit for the dose equivalent of all tissues prevents non-stochastic radiation effects. With stochastic radiation effects probably exist no threshold doses; therefore the ALARA principle must be applied concerning radiation protection. The individual risk by stochastic radiation effects in its linear, linear-quadratic and quadratic extrapolations, respectively, is discussed in detail. The effective stochastic dose equivalent (H/sub eff/) as well as collective dose and collective damage are outlined.
In Korea, the Proton Engineering Frontier Project (PEFP) is building a proton linear accelerator facility with energy up to 100MeV and a beam current of 20mA. In this study, a radiation field after shutdown in the accelerator facility of the PEFP was evaluated for the purpose of the radiation shielding by using MCNPX code. A facility modeling was performed for the accelerator tunnel building, accelerator chain, target rooms and beam experiment hall. And radiation source terms were evaluated in the facility. With this facility, model and radiation source terms, the concentration of 41Ar was evaluated and the cooling time satisfying regulation in Korea was calculated.
Delayed cerebral necroses after irradiation are to be divided into hemispheric and midline lesions, as they differ from each other in several aspects. Apart from the symptoms, they are differing in the duration of latency, in the course and prognosis, and also with regard to morphology. Though there is no doubt that radiation tolerance of cerebral midline structures is relatively limited, on biological grounds, evidence of a difference between the tolerated doses could not be given from the existent inhomogeneous radiation data, with the help of the NSD-concept. Radiation planning for the region of the head, nevertheless, carefully should avoid in every case to involve the structures of the cerebral midline.
Remote-controlled handling systems are required for work to be done in the decommissioning and dismantling of nuclear facilities. These systems are equipped with electronic devices suitable for use in working environments affected by ionizing radiation. The publication explains the step-wise progress achieved for improving the radiation resistance of electronic devices with the example of a four-quadrant controlling device for the motors of a manipulator. The radiation resistance of the device could be enhanced to radiation energies of 5.500 Gy. This means that a manipulator vehicle equipped with this controlling device can take up to approx. 15 kGy all in all, taking into account its own shielding properties. (DG).
Investigations were carried out of radiation level around Daya Bay for three times since the construction and operation Daya bay Nuclear Power Station and Lingao Nuclear Power Station in Guangdong province in the period of 1988 to 2000. As shown by the investigation, the radiation levels both in the field and indoors remains unchanged by and large but slightly higher than before on the roads. Also this paper gives the analysis of variations in radiation levels form site to site and from time to time. It was shown that, for environmental ? radiation levels measurements, typical measuring sites have significant impact on the meaning results. (authors)
Exercise promotes weight loss and improves insulin sensitivity. However, the molecular mechanisms mediating its beneficial effects are not fully understood. Obesity correlates with increased production...Full Text Available
This patent describes a process for the conversion of low molecular weight alkanes to higher molecular weight hydrocarbons. It comprises: contacting the low molecular weight alkanes, at an elevated temperature, with oxygen and a catalyst of the formula Zn{sub a}A{sub b}M{sub c}M'{sub d}O{sub x} wherein A is Li, Na, K, or mixtures thereof; M is Al, Ga, Cr, La, Y, Sc, V, Nb, Ta, Cu or mixtures thereof; M' is Cs, Rb, Mg, Ca, Sr, Ba, Sm, Pb, Mn, Sb, P, Sn, Bi, Ti, Zr, Hf, or mixtures thereof; a if from about 1 to about 20; b is from about 0.1 to about 20; c is from about 0 to about 5 d is from about 0 to about 20, and x is a number needed to fulfill the valence requirements of the other elements; provided that at least one c and d is a t least 0.1; and when M' is Sn, c must be at least 0.1.
The ability to enter a hypometabolic state upon restriction of caloric intake is pivotal for animal survival: balancing the energy budget in endotherms can be a real struggle when food is not...Full Text Available
PurposeTo date there remains no effective therapy for metastatic melanoma and at the molecular level disease progression remains poorly understood. Recent work by...Full Text Available
BackgroundDuring the last ten years, major advances have been made in characterizing and understanding the evolution of mitochondrial DNA, the most popular marker of molecular biodiversity....Full Text Available
We use a novel normal mode analysis of an elastic network model drawn from configurations generated during microsecond all-atom molecular dynamics simulations to analyze the mechanism of auto-inhibition...Full Text Available
One membrane oxygen enricher (Oxygen Enrichment Company OE-4E) and four molecular sieve (MS) concentrators (Mountain Medical Econo2, De Vilbiss MINI DeVO2, Cryogenic Roomate III, and Mountain Medical...Full Text Available
In this study, free electron laser (FEL) with selective wavelength was used to induce structure changes of biomolecules, which were characterized by FTIR spectroscopy. For understanding of the interactions between FEL and biomolecules as well as biological tissues, the biomolecules investigated are ATP, ADP, AMP, t-RNA, D-ribose and the complex of SmCl_3-D-ribose. Their FTIR spectra before and after irradiation of FEL show molecular structure variations of the samples after irradiation of FEL, especially the rearrangement of their hydrogen bond networks. Along with the various irradiation wavelengths, irradiation time and molecular structures, the changes after irradiation are different for these molecules. In the FTIR spectra after irradiation, the phenomenon that the bands split into several peaks indicates the existence of several structures, conformations and configurations, which may be prompted by multiple photons process induced by FEL. ...
Disorders of mitochondrial fat metabolism lead to sudden death in infants and children. Although survival is possible, the underlying molecular mechanisms which enable this outcome have not yet been...Full Text Available
BackgroundThe molecular mechanisms of variations in individual longevity are not well understood, even though longevity can be increased substantially by means of diverse experimental...Full Text Available
A statistical treatment has been applied to interpret the experimental data on the Xe M-shell vacancy production in slow 1.05 MeV Xe-Xe collisions and is shown to give better agreement with experiment than that of the molecular-orbital models.
BackgroundSpindle cell carcinoma (SpCC) is a rare microscopic type of cancer of the mouth and oropharynx. Although SpCC is thought to arise from squamous cell carcinoma (SCC), it...Full Text Available
The effects of selected ligands on the structure of the truncated heavy-chain chemomechanical motor domains of Drosophila ncd and human kinesin were compared using the technique of transient electric...Full Text Available
PurposeA prolonged seizure, status epileptics (SE), is a potent stimulus for increased neurogenesis in the dentate gyrus of the hippocampus. Molecular mechanisms...Full Text Available
Hibernators are unique among mammals in their ability to survive extended periods of time with core body temperatures near freezing and with dramatically reduced heart, respiratory, and metabolic rates...Full Text Available
The intracellular bioavailability of lead (Pb) at low dosage levels in major target organs such as the kidney and brain appears to be largely determined by complexation with a group of low molecular...Full Text Available
The increasing demand for molecular diagnostics in clinical microbiology laboratories necessitates automated sample processing. In the present study, we evaluated the performance of the MagNA Pure LC...Full Text Available
Nucleic acids are molecules of choice for both established and emerging nanoscale technologies. These technologies benefit from large functional densities of ‘DNA processing elements’...Full Text Available
Emphasis was put on the comparative quantitative structure-activity approaches to the exploration of action mechanisms of structurally different classes of compounds showing the same type of activity...Full Text Available
We describe the characteristics of the rapidly rotating molecular disk in the nucleus of the mildly active galaxy NGC4258. The morphology and kinematics of the disk are delineated by the point-like...Full Text Available
Ion-channels can be activated (gated) by a variety of stimuli including chemicals, voltage, mechanical force or temperature. Whereas molecular mechanisms of ion-channel gating by chemicals and...Full Text Available
BackgroundThe phylogenetic relationships among the holoparasites of Rafflesiales have remained enigmatic for over a century. Recent molecular phylogenetic studies using the mitochondrial...Full Text Available
Current drug treatments for post-menopausal osteoporosis cannot eliminate bone fractures, possibly because the mechanisms responsible for bone loss are not fully understood. Although research within...Full Text Available
The clotting activity of Staphylococcus aureus strain 104 was purified 46,000-fold, but absolute purity was not achieved. Carbohydrate content of the purified material was not more than 5%. Elution...Full Text Available
Aminopeptidase II, one of the two major aminopeptidases in the giant alga Chara australis, was partially purified. Its molecular weight was estimated to be about 80,000 by gel permeation...Full Text Available
Patients with pancreatic cancer normally present with advanced disease that is lethal and notoriously difficult to treat. Survival has not improved dramatically, despite routine use of chemotherapy...Full Text Available
BackgroundGene promoters can be in various epigenetic states and undergo interactions with many molecules in a highly transient, probabilistic and combinatorial way, resulting in...Full Text Available
Mutant strains of the yeast Saccharomyces cerevisiae which lack functional Cu,Zn superoxide dismutase (SOD-1) do not grow aerobically unless supplemented with methionine. The molecular basis of this...Full Text Available
In our quest for novel genes required for the development of the embryonic peripheral nervous system (PNS), we have performed three genetic screens using MAb 22C10 as a marker of terminally differentiated...Full Text Available
Non-Hodgkin lymphoma is a common feature of AIDS. Approximately 30-40% of these tumors exhibit clinical features suggestive of endemic Burkitt lymphoma: they are aggressive malignancies that occur in association with Epstein-Barr virus infection, they arise in the setting of immunosuppression, and they carry t(8;14) translocations without detectable rearrangement of the MYC oncogene. To understand the molecular basis of these parallels, the authors analyzed a case of Epstein-Barr-positive AIDS-associated undifferentiated lymphoma. Southern blots show that the tumor exhibits immunoglobulin joining segment rearrangement but no rearrangement of the MYC oncogene. Cloning of the rearranged joining segment allowed the isolation of recombinant clones encompassing the translocation breakpoint, and sequencing of the translocation junction disclosed that the breakpoint is situated 7 base pairs from the chromosome 14 site involved in a previously described endemic Burkitt ...
A 42% (70 of 167 isolates) incidence of resistance to 20 micrograms of trimethoprim per ml was found among clinical isolates of coagulase-negative staphylococci from two hospitals. A specific trimethoprim...Full Text Available
The sequence-dependent structural variability and conformational dynamics of DNA play pivotal roles in many biological milieus, such as in the site-specific binding of transcription factors to target...Full Text Available
BackgroundThe zebrafish is recognized as a versatile cancer and drug screening model. However, it is not known whether the estrogen-responsive genes and signaling pathways that are...Full Text Available
BackgroundHepatitis A virus (HAV) strains detected in environmental and clinical samples were analysed to characterize the genotypes of HAV circulating in Greece. Fifty (50) sewage...Full Text Available
The walleye dermal sarcoma is a mesenchymal tumor which seasonally affects up to 27% of adult walleye fish (Stizostedion vitreum). It arises multicentrically in the dermis, in which its development...Full Text Available
The fungus Cryptococcus neoformans is a major cause of morbidity and mortality in patients with impaired CD4+ T cell function, particularly those with AIDS. To identify...Full Text Available
Aluminium (Al3+) toxicity is the primary factor limiting crop production on acidic soils worldwide. In addition to an application of lime for soil amelioration, Al3+ resistant plant varieties have been deployed to raise productivity on such hostile soils. This has been possible due to the exploita...
Flavone and isoflavone phytoestrogens are plant chemicals and are known to be competitive inhibitors of cytochrome P450 aromatase with respect to the androgen substrate. Aromatase is the enzyme that...Full Text Available
The Far UpStream Element (FUSE) regulatory system promotes a peak in the concentration of c-Myc during cell cycle. First, the FBP transcriptional activator binds to the FUSE DNA element upstream...Full Text Available
Borrelia burgdorferi is the causative agent of Lyme disease, a tick-borne spirochetosis with a worldwide prevalence. To assist the categorization and typing of fresh isolates from global foci, we have...Full Text Available
AimsThe aims of the study were to study the effect of pre-operative treatment on the expression of tumour-related proteins and to correlate the expression of these...Full Text Available
Pyrethroid insecticides have been extensively used in China and worldwide for public health pest control. Accurate resistance monitoring is essential to guide the rational use of insecticides and resistance...Full Text Available
The Dot/Icm-translocated Ankyrin B (AnkB) F-box effector of Legionella pneumophila is essential for intra-vacuolar proliferation and functions as a platform for the docking of polyubiquitinated...Full Text Available
Aluminium (Al) toxicity, affecting around half of the world¿s arable land, severely hinders the ability of crop plants to utilize moisture and nutrients by restricting root growth and function. Among the cultivated cereals, rye is the most Al-tolerant and represents an important potential source of ...
Methylosulfonomonas methylovora M2 is an unusual gram-negative methylotrophic bacterium that can grow on methanesulfonic acid (MSA) as the sole source of carbon and energy. Oxidation...Full Text Available
A high performance liquid chromatography (HPLC) procedure suitable for the simultaneous determination of the molecular size and concentration of macromolecular hyaluronate and proteoglycans in synovial...Full Text Available
The methanogenic community in hydrothermally active sediments of Guaymas Basin (Gulf of California, Mexico) was analyzed by PCR amplification, cloning, and sequencing of methyl coenzyme M reductase...Full Text Available
IntroductionNormal and neoplastic breast tissues are comprised of heterogeneous populations of epithelial cells exhibiting various degrees of maturation and differentiation. While...Full Text Available
The identification of predictive biomarkers is at the core of modern toxicology. So far, a number of approaches have been proposed. These rely on statistical inference of toxicity response from either...Full Text Available
Despite the demonstrated clinical efficacy of CD20 monoclonal antibody (mAb) for lymphoma therapy, the in vivo mechanisms of tumor depletion remain controversial and variable. To identify the molecular...Full Text Available
Antibodies of the IgM type present in rabbit anti-epiglycanin antiserum were purified by (NH4)2SO4 precipitation and by ion-exchange, affinity and gel-filtration chromatography. After papain treatment...Full Text Available
The soluble subcellular fraction of a chlB mutant contains an inactive precursor form of the molybdoenzyme nitrate reductase, which can be activated by the addition to the soluble fraction of protein...Full Text Available
The physicochemical nature of a silicoaluminophosphate with the faujasite structure has been studied. The molecular sieve framework contains a homogeneous distribution of silicon, aluminum, and phosphorus and is negatively charged. Combustion in air of the charge-compensating organic cations produces hydroxyl groups which exhibit Broensted acidity.
BackgroundThe Gene Ontology (GO) is a well known controlled vocabulary describing the biological process, molecular function and cellular...Full Text Available
Insulin resistance in skeletal muscle is a key phenotype associated with type 2 diabetes (T2D) for which the molecular mediators remain unclear. We therefore conducted an expression analysis of human...Full Text Available
Methylation of the arginine residues of histones by methyltransferases has important consequences for chromatin structure and gene regulation; however, the molecular mechanism(s) of methyltransferase...Full Text Available
Calorie restriction (CR) induces a metabolic shift towards mitochondrial respiration; however, molecular mechanisms underlying CR remain unclear. Recent studies suggest that CR-induced mitochondrial...Full Text Available
A nodulation plasmid, pRtr-514a, of molecular size 180 megadaltons (Mdal) was identified in Rhizobium trifolii strain NZP514. This plasmid was absent in both spontaneous and heat-cured Nod- derivatives...Full Text Available
BACKGROUND: Mitochondrial changes have been described in muscle tissue in acquired hypothyroidism. Among the molecular mechanisms by which thyroid hormones regulate expression of nuclear genes encoding...Full Text Available
Heat shock proteins (Hsp) are a family of stress-inducible molecular chaperones that play multiple roles in a wide variety of animals. However, the roles of Hsps in parasitic nematodes remain largely...Full Text Available
High-resolution near-infrared and far-infrared observations are presented of the southeastern molecular cloud fragment in the IC 5146 dark cloud. These observations rule out earlier suggestions for the formation of massive stars in this fragment.
BackgroundCucumber, Cucumis sativus L. is an important vegetable crop worldwide. Until very recently, cucumber genetic and genomic resources, especially molecular...Full Text Available
Stargardt-like macular degeneration (STGD3) is an early onset, autosomal dominant macular degeneration. STGD3 is characterized by a progressive pathology, the loss of central vision, atrophy...Full Text Available
The binding of amphiphilic molecules to lipid bilayers is followed by 19F NMR using chemical shift and line shape differences between the solution and membrane-tethered states of...Full Text Available
Larvae of an anhydrobiotic insect, Polypedilum vanderplanki, accumulate very large amounts of trehalose as a compatible solute on desiccation, but the molecular mechanisms underlying...Full Text Available
The programming of cellular networks to achieve new biological functions depends on the development of genetic tools that link the presence of a molecular signal to gene-regulatory activity. Recently,...Full Text Available
A 48-hour course of intravenous unfractionated heparin (UFH) is the standard of treatment in conjunction with fibrin-specific thrombolysis in ST-elevation myocardial infarction (STEMI). In recent trials,...Full Text Available
One of the most pervasive ideas regarding the causes of aging is that longevity is constrained in large measure by damage to macromolecules. An increasing body of cellular and molecular data, generated...Full Text Available
While pleiotropic adaptive mutations are thought to be central for evolution, little is known on the downstream molecular effects allowing adaptation to complex ecologically relevant environments. Here...Full Text Available
Molecular genetic analysis of Borrelia burgdorferi, the cause of Lyme disease, has been hampered by the absence of any means of efficient generation, identification, and complementation...Full Text Available
Recently developed molecular methods have made it possible to characterize mixed microflora in their entirety, including the substantial numbers of bacteria which do not grow on artificial culture media....Full Text Available
Many epidemiological evidences have proven the association between smoking and periodontal disease. The causality can be further established by linking findings of traditional epidemiological studies...Full Text Available
Self-renewal of spermatogonial stem cells (SSCs) is the foundation for maintenance of spermatogenesis throughout life in males and for continuation of a species. The molecular mechanism underlying stem...Full Text Available
A simulation is developed that qualitatively describes the small-zone-gel-filtration behaviour of a reversibly associating protein. The results reflect the dependence of the apparent molecular weight...Full Text Available
Molecular analysis of the amo gene cluster in Nitrosococcus oceani revealed that it consists of five genes, instead of the three known genes, amoCAB....Full Text Available
Tail plates obtained from T4D amber mutants were examined with respect to sedimentation behavior, subunit molecular weights, amino acid composition, isoelectric points, and morphology. Intact plates...Full Text Available
Designer cellulosomes are precision-engineered multienzyme complexes in which the molecular architecture and enzyme content are exquisitely controlled. This system was used to examine enzyme cooperation...Full Text Available
Two additional hyperfine components of the interstellar radical C3H were detected. In addition, methanol was discovered in interstellar clouds. The abundance of HCCN and various chemical isomers in molecular clouds was investigated.
The evolution of sex remains a hotly debated topic in evolutionary biology. In particular, studying the origins of the molecular mechanisms underlying sexual reproduction and gametogenesis (its fundamental...Full Text Available
Molecular chaperones protect cells from the deleterious effects of protein misfolding and aggregation. Neurotoxicity of amyloid-beta (Aβ) aggregates and their deposition in senile plaques are...Full Text Available
The complete RNA genome of the avian nephritis virus (ANV) associated with acute nephritis in chickens has been molecularly cloned and sequenced. Excluding the poly(A) tail, the genome comprises 6,927...Full Text Available
SummaryThe prevalence of paralogous enzymes implies that novel catalytic functions can evolve on preexisting protein scaffolds. The weak secondary activities of proteins, which...Full Text Available
A general procedure for stabilization of O2-labile enzymes exploiting "salting out" of oxygen from the microenvironment in the molecular layers immediately adjacent to charged surfaces of polyionic...Full Text Available
Leaf senescence is a developmentally programmed degeneration process, which is fine tuned by a complex regulatory network for plant fitness. However, molecular regulation of leaf senescence is poorly...Full Text Available
Traditional approaches to the study of hormones and cognition have been primarily observational or correlational in nature. Because this work does not permit causal relationships to be identified,...Full Text Available
Autophagic adapters including p62/SQSTM1 recognize polyubiquitinated autophagic targets such as toxic protein aggregates. Recently reporting in Molecular Cell, Filimonenko et al. provide evidence...Full Text Available
The decline in immune function with aging, known as immunosenescence, has been implicated in evolutionarily diverse species, but the underlying molecular mechanisms are not understood. During aging...Full Text Available