Electron

A detailed spectroscopic and photophysical study has been carried out on a series of heterocyclic compounds-known to display nonlinear optical properties-consisting on a electron donating thienylpyrrolyl p-conjugated system functionalized with an electron acceptor benzothiazole moiety. The absorption, emission and triplet-triplet absorption together with all relevant quantum yields (fluorescence, intersystem crossing and internal conversion), excited state lifetimes and the overall set of deactivation rate constants (k F , k IC and k ISC) were obtained in solution at room (293 K) and low (77 K) temperature. The optimized ground-state molecular geometries for the compounds together with the prediction of the lowest vertical one-electron excitation energy and the relevant molecular orbital contours for the compounds were also determined using density functional theory (DFT) at the B3LYP/3-21G* level. The experimental results showed that the photophysical properties are influenced by the relative position of the pyrrole and thiophene relative to the benzothiazole group.

A first preliminary interlaboratory trial was planned to prepare ISO/DIS 12010: Water quality-determination of short chain polychlorinated alkanes (SCCP) in watermethod using GC/MS and electron capture negative ionisation (ECNI). The task was to determine the sum of short chain polychlorinated n-alkanes with carbon chain lengths of C 10-C 13 and a chlorine content between 49 and 67% in water by GC-ECNI-MS and quantification by multiple linear regression described in ISO/DIS 12010 as the compulsory method. Distributed samples were obtained from a real water extract spiked with a target concentration of 0.4 mg/mL sum of SCCP, i.e. the environmental quality target level according to the Water Framework Directive. The interlaboratory trial included the calibration, a column chromatographic clean up, a concentration step and an integration of chromatographic unresolved humps as well as the quantification with multiple linear regression. Reproducibility standard deviations between 21.5 and 22.9% were achieved by 17 participating laboratories from four countries. The method outlined no significant difference of the results between the standard solution and a real water matrix extract. On the basis of this succeeded preliminary interlaboratory trial the final interlaboratory trial for validation of ISO 12010 was prepared in autumn 2010.

The aim of this study was to evaluate polyurethane percutaneous endoscopic gastrostomy (PEG) tube degradation and the role played by fungi. The inner surfaces of 20 used polyurethane tubes were brushed, and the brushing end was incubated for 7 days in Saburaud broth and cultured if fungal growth occurred. Three tubes used for 12 (sample 12w), 17 (sample 17w), and 96 (sample 96w) weeks and two new tubes were cut to produce several 4-cm-long equal halves. Six samples from the new tubes were considered control samples (Co sample), seven were incubated in Saburaud broth (Co sample + Sa.), and seven in the broth supplemented with Candida albicans (Co sample + Sa. + Ca). All samples underwent morphological examination by electron microscopy and differential scanning calorimetry measurements (DSC). All tubes had fungal colonization. DSC showed deterioration in all tubes including the new ones; adding Candida albicans had no additional effects. Morphological examination by electron microscopy showed a regular pattern in the Co sample, and thick biofilm, holes, and crevices in samples 12w, 17w, and 96w. The more the tubes had been used, the more severe were the changes. The Co sample + Sa and the Co sample + Sa + Ca showed no changes in the inner surface, but cryogenically fractured surfaces had holes and crevices. Yeasts constantly colonize PEG tubes and are likely to contribute to polyurethane deterioration. The impairment of new PEG tubes incubated in Saburaud broth suggests that other factors also play a role in polyurethane deterioration.

This paper lays out the mechanics of creation in the 3-spaces model of an electron-positron pair as a photon of energy 1.022 MeV or more is destabilized when grazing a heavy particle such as an atom's nucleus, thus converting a massless photon into two massive .511 MeV/c 2 particles charged in opposition. An alternate process was also experimentally discovered in 1997, that involves converging two tightly collimated photon beams toward a single point in space, one of the beams being made up of photons exceeding the 1.022 MeV threshold. In the latter case, electron/positron pairs were created without any atom's nuclei being close by. These two observed processes of photon conversion into electron-positron pairs set the 1.022 MeV photon energy level as the threshold starting at which massless photons become highly susceptible to become destabilized into converting to pairs of massive particles.

Electrochemical Atomic Layer Epitaxy (ECALE) was used to obtain multi-atomic layers of CdS on a single crystal Ag(111) substrate. Electrochemical stripping measurements indicate that the amount of Cd and S in these films corresponds to the stoichiometric 1:1 ratio. This result was confirmed by X-ray photoelectron spectroscopy (XPS). Measurements performed by X-ray photoelectron diffraction (XPD) permitted the determination of the structure and orientation of the CdS phase. This structure turned out to be the wurtzite lattice with the (0001) plane parallel to the substrate plane and a Cd type termination.

If P is a differential operator with constant coefficients, an identity is derived to calculate the action of e P on the product of two functions. In many-body theory, P describes the interaction Hamiltonian and the identity yields a hierarchy of Green functions. The identity is first derived for scalar fields and the standard hierarchy is recovered. Then the case of fermions is considered and the identity is used to calculate the generating function for the Green functions of an electron system in a time-dependent external potential.

The purpose of this study is to evaluate the dosimetry across the junction between an enface 9 MeV electron field and 6 MV parallel opposing photon fields for two photon configurations: (1) laterally opposed divergent beam set-up and (2) laterally opposed half-beam (non-divergent) set-up using asymmetric collimator jaws. In this study, film dosimetry technique was performed to measure dose profiles at depths of 1, 2, and 3 cm in the junction of the matching photon and electron fields. In order to investigate the changes in the dose distributions due to set-up uncertainties, dose profiles were measured at these depths using no gap, 2 and 4 mm overlaps and gaps between the photon and electron fields. A 2 mm gap resulted in approximately +15% and +20% hot spots in the photon field at 1 and 3 cm depths, respectively, for divergent photon beams. However, at 2 cm depth, an approximately +30% hot spot and −10% cold spot occurred in the junction region. Four millimeter overlap and gap resulted in an unacceptable dose inhomogeneity in the junction. As a result of this study, the magnitudes of hot and cold spots might be clinically acceptable for 2 mm gap between photon and electron fields.

The segregation of minor components such as flow agents, in an industrial coil coating based on epoxy resins crosslinked with a urea formaldehyde resin and applied to a hot-dipped galvanized steel (HDGS) substrate, has been investigated by high resolution XPS. The addition of a low amount of flow agent in the coating formulation leads to changes in the surface elemental composition. High-resolution monochromated XPS C1s spectra can be peak-fitted taking into account all functionalities of the respective components of the formulation. The examination of both the elemental and chemical surface compositions clearly demonstrates that the use of flow agent in the process leads to its preferential segregation towards the air-film interface. This result is interpreted in terms of minimisation of the surface free energy of the final coil coating. It is also possible to monitor the extent of crosslinking undergone within the coil coating system, using the peak-fitting in the same manner as above, and it was concluded that the system is fully crosslinked.

In the last few decades, many researches on the effects of magnetic field (MF) on water have been reported; however, still many arguments and doubts are present. This review aims to focus on the basic properties implied in magnetic phenomena generation at the atomic and electronic level of matter. Fundamentals of magnetism and origin of magnetic effect will be discussed. Both paramagnetism and diamagnetism are very crucial in the examination of atomic and molecular structure; however, these effects are very weak and have no real practical importance. Large scale magnetic effects resulting in commercially important materials appear in atoms and ions of only a few metallic elements notably Fe, Co, Ni, and some of the rare earths. In alloys or oxides of some materials containing these elements and some neighboring ions such as Mn, there is a crucial improvement of the atomic spin effect. This enhancement comes about from the cooperative interaction of large numbers (10 13 – 10 14) of these atomic spins producing a region where all atomic spins within it are aligned parallel (positive exchange interaction). These materials are called ferromagnetic. In spite of the achieved performances on MF technologies, there is a huge work to be performed for better understanding and controlling of magnetic water treatment.

Special care of superficial lesions surrounding critical structures, such as an eye, may require tight margins. When this is the case, small megavoltage electron treatment fields and nonstandard treatment distances become necessary. When the field size is found to be less than the practical range of the electron beam, dosimetric measurements should be performed. This research includes data proving that very small electron fields can be employed for treatment with appropriate beam flatness and penumbra. This is accomplished by first coning down the incident beam to a small field size, then secondly by adding a single lead sheet to the patient's skin surface. The aperture of the sheet is required to be greater than 2 ؋ 2 cm 2 in size, and must be cut properly to adequately confine the treatment area.

bjective: This study evaluated the surface degradation effect of acidulated phosphate fluoride (APF) gel exposure on the glassy matrix ceramics as a function of time. Material and methods: Disc-shaped ceramic specimens (N = 120, 10/per ceramic material) were prepared in stainless steel molds (inner diameter: 5 mm, height: 2 mm) using 6 dental ceramics: 3 indicated for ceramic-fused-to-metal (Vita Omega 900, Carmen and Vita Titankeramik), 2 for all-ceramic (Vitadur Alpha and Finesse ® Low Fusing) and 1 for both types of restorations (IPS d.SIGN). The specimens were wet ground finished, ultrasonically cleaned and auto-glazed. All specimens were subjected to calculation of percentage of mass loss, surface roughness analysis and topographical description by scanning electron microscopy (SEM) before (0 min) and after exposure to 1.23 % APF gel for 4 min and 60 min representing short-and long-term etching effect, respectively. The data were analyzed using two-way ANOVA with repeated measures and Tukey`s test (α=0.05). Results: Significant effect of the type of the ceramics (p=0.0000, p=0.0031) and exposure time (p=0.0000) was observed in both surface roughness and percentage of mass loss values, respectively. The interaction factor between both parameters was also significant for both parameters (p=0.0904, p=0.0258). Both 4 min (0.44±0.1 -0.81±0.2 µm) and 60 min (0.66±0.1 -1.04±0.3 µm) APF gel exposure created significantly more surface roughness for all groups when compared to the control groups (0.33±0.2 -0.68±0.2 µm) (p<0.05). There were no significant differences in percentage of mass loss between the ceramics at 4 min (p>0.05) but at 60 min exposure, IPS d.SIGN showed the highest percentage of mass loss (0.1151±0.11). The mean surface roughness for Vita Titankeramik (0.84±0.2 µm) and Finesse ® Low Fusing (0.74.±0.2 µm) was significantly higher than those of the other ceramics (0.59±0.1 µm -0.49±0.1 µm) and Vita Titankeramik (p<0.05) regardless of the exposure time. A positive correlation was found between surface roughness and percentage of mass loss for all ceramic materials [(r=0.518 (Vitadur Alpha), r=0.405 (Vita Omega 900), r=0.580 (Carmen), r=0.687 (IPS d.SIGN), r=0.442 (Finesse ® Low Fusing), r=0.572 (Vita Titankeramik), Pearson`s correlation coefficient)]. The qualitative SEM analysis showed evidence of corrosive attack on all of ceramics at varying degrees. Conclusions: The ceramics indicated for either metal-ceramic or all-ceramic restorations were all vulnerable to surface texture changes and mass loss after short-term and long-term APF gel exposure.

According to Yangton and Yington Theory, only spin particles such as photon and electron can have wave particle duality. Appling particle waves in study of Single Slit Diffraction and Double Slit Interference, a new type of mechanisms: attractive interference and repulsive interference are proposed instead of constructive interference and destructive interference, which gives a better explanation to particle depletion in destructive interference. In case of single particle experiment, subject to the traveling time, direction and distance of each particle, attractive interference and repulsive interference can still happen but at much less frequency. Furthermore, which-way experiment and the Complementarity Principle are proven incorrect and both particle and wave properties on photon and electron can coexist at the same time.

We study the possible distortions of the evolution of the early universe caused by the oscillations of a standard neutrino (ν c , ν μ or ν τ ) into a light “sterile” neutrino state, a gauge group singlet ν s . The effects on the standard big bang nucleosynthesis are considered in the full ...

On 30 April 1897 J. J. Thomson (Cavendish Professor of Physics at Cambridge) announced the results of his previous four months’ experiments on cathode rays. The rays, he suggested were negatively charged subatomic particles which were a universal constituent of matter, and whose arrangement determined the chemistry of the element. He called the particles ‘corpuscle’ but they became known as ‘electrons’ and Thomson has been hailed as their ‘discoverer’. This paper examines the acceptance of Thomson’s corpuscle theory through a comparison of two accounts of the conceptual build-up to the electron, one by the British physicist Oliver Lodge, and the other by the German, Walter Kaufmann. It concludes that the British and German concepts had fundamentally different foundations, and that Thomson's experiments were successful largely because they were sufficiently ambiguous to be adopted by both theoretical camps

First-order many-body theory has been used to calculate correlation and coherence parameters for the electron impact excitation of the 31P1 and 33P1 and states of neon. Both LS-coupled and spin-orbit-coupled results are reported for the 31P1 state. Calculations were completed for E=20, 30, 40, 50, 80, 100 and 120 eV electron impact energies. Theoretical results are compared with those that

Monte Carlo track-structure simulation provides a near accurate description of the passage of charge particle in water as a surrogate for biological tissue. Radiation transport codes and Monte Carlo track-structure codes are widely used in radiation biophysics, dosimetry and microdosimetry, clinical radiotherapy, in space radiation program and accelerator design and research. Over the past decade the number of Monte Carlo track codes simulating a variety of different types of radiations has increased rapidly. In this paper we provide a review of recent progress in the development of particle track simulation for electron, low-energy light ions and finally the recent model development for the low-energy electron cross-sections in liquid water.

This review summarizes the biological properties of the junctional epithelium, focusing on its developmental aspects, wide intercellular spaces and desmosomes, dense granules, permeability barrier, phagocytotic activity, adhesive structures and nerve terminals. It also discusses the morphology and functions of long junctional epithelium and peri-implant epithelium. Junctional epithelium is derived from the reduced enamel epithelium during tooth development. Apoptosis occurs in the border between oral and reduced enamel epithelia during tooth eruption. Junctional epithelium expresses a cytokeratin-19 immunoreaction, suggesting that this protein is a consistent differentiation marker. Wide intercellular spaces, which contain neutrophils and nerve endings, are formed as there are fewer desmosomes than in the oral epithelium. Dense, membrane-bound granules in the epithelium might correspond with membrane-coating granules, as revealed by their shape, components and freeze-fracture images. Junctional epithelium with high permeability contains exogenously expressed a-defensins, while stratified epithelia contain endogenously expressed bdefensins. The phagocytotic activity in this epithelium remains unclear. Integrin-a6b4 and laminin-5 form a complex in the tooth surface internal basal lamina. Long junctional epithelium created experimentally attaches to the cementum surface by hemidesmosomes and basal lamina. The periimplant epithelium differs in proliferation and in adhesive structure from the normal junctional epithelium. In conclusion, wide intercellular spaces and poorly developed desmosomes are closely correlated with a permeable nature. There is still uncertainty over the phagocytotic activity of the epithelium. Integrin-a6b4 and laminin-5 form a significant complex in the internal basal lamina. Junctional epithelium receives a rich sensory nerve and has a high rate of cell turnover. Long junctional epithelium can be produced rapidly during wound healing, due to high proliferative activity. Periimplant epithelium might be a poorly adhered and permeable epithelium.

A model of the electron is proposed in which it is composed of a known and detectable particle. This model clearly defines what is mass, what is energy and why E = mc 2 . It shows that the special relativity corrections of mass, length and time with velocity are automatically a function of the structure of an electron as it moves. It also proposes the origin of electric charge and uses that origin to derive the equation for the Bohr magnetron. It shows that the electron's spin of ½ħ is simply angular momentum, further explaining why the electron has only two states of spin. This model gives an expression for the radius of an electron, at the same time pointing out why it has been detected as a point particle, yet still has angular momentum of ½ħ. It explains why the mass of an electron increases with velocity while its spin and charge remain the same and its magnetic moment decreases, as well as why its charge spirals when it travels through space. This model gives a physical reason for the existence of the de Broglie wavelength and derives the expression for it. As well as matching the known properties of an electron it also makes predictions of previously unknown properties, pointing out that they may have been detected but not recognized as such.

Silica bearing octadecylsilane groups were synthesized by grafting and the sol-gel method. In the former, commercial silica was chemically modified with octadecyltrimethoxisilane (ODS), while in the latter, it was produced by reacting tetraethoxysilane and ODS in alkaline milieu. Carbon content was much lower in the case of grafting reaction (1.2 and 3.5 wt.%) in comparison to that achieved with the sol-gel method (2.5-68.6 wt.%). Hybrid silicas were characterized by X-ray photoelectronic spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), 13 C resonance nuclear magnetic spectroscopy (NMR), laser scattering and scanning electronic microscopy (SEM). Alkyl chain conformation was shown to depend on the preparation route. Grafting yields hybrid silica having a liquid-like conformation, while in silica prepared by the sol-gel method, the C18 chains present a more ordered and crystalline conformation. The presence of alkyl chains increases the particle size distribution for hybrid silicas prepared by the grafting method.

Ionosfer adalah lapisan udara yang merupakan bagian dari atmosfer atas bumi yang terletak pada ketinggian sekitar 60  km  –  600  km diatas permukaan bumi. Lapisan tersebut terdiri dari partikel-partikel bermuatan (ion dan elektron)  yang biasa  disebut plasma.Pada ketinggian tersebut sebagian dari molekul-molekul udara ada yang terionisasi. Ionisasi adalah peristiwa terletaknya elektron dari atom atau molekul netral, sehingga terbentuk partikel bermuatan positif  yang disebut ion  dan partikel bermuatan negatif  yang disebut dengan  elektron.  Total Electron Content (TEC) adalah  jumlah elektron 2 dalam kolom vertikal (silinder) berpenampang seluas 1 m    sepanjang lintasan sinyal    perangkat GPS yang dilalui di lapisan ionosfer pada ketinggian sekitar 350 km.  Pada hasil riset akan diketahui bahwa ionosfer hanya dapat memantulkan frekuensi tinggi.

The finding of non-viral carriers for the delivery and release of pharmaceutical and biological compounds to ill organs and tissues is one of the most widely investigated topic in medicinal and biological chemistry in the last decades. Prior to being used as drug vehicles in the living organisms, all of the new carriers are required to be fully characterized from a physico-chemical point of view, with respect to stability, charge, size, mobility, etc. To this aim, several molecular and bulky techniques have been employed for characterization. This review considers the results obtained with a molecularly oriented spectroscopic method, i.e. electron spin resonance (ESR). The application of this technique in its various forms derived from continuous-wave (cw-ESR) and pulsed-wave (pw-ESR) modes are reviewed. In particular, carriers such as liposomes (intended for gene therapy, boron neutron capture therapy, oxymetry, and others), micelles, hydrogels, nanoparticles, dendrimers, cyclodextrins and cucurbit[n]urils are considered.

Polyethylene Glycol Monoalkyl Ethers, C x H 2x+1 (OC 2 H 4 ) n OH, (PEGMAE), are polar compounds like Polyethylene Glycols (PEG) and they undergo microbial degradation which produces toxic substances that are potentially dangerous to the environment. Therefore, the purpose of this study is to carry out proper identification and characterization of these compounds. The Electron Ionization (EI) and Chemical Ionization (CI) spectra of various PEGMAE were obtained by Gas Chromatography/Mass Spectrometry (GC/MS) and were used to identify and characterize these compounds. The characteristic cleavages in the EI and CI reactions of PEGMAEs were also studied. The results obtained showed that the methane CI mass spectra of the PEGMAE contain MH + ions and fragment ions similar to those found in their EI mass spectra. The relative abundances of the MH + ions are low, variable and increase with increasing sample size across the chromatographic peaks; but do not increase with increasing x or n. The base peaks of the low mass oligomers (x3) are PEG related (e.g., m/z 45, 59) but those of higher mass oligomers (x4) include the ion at m/z 63 (HOC 2 H 4 OH) H + or m/z 107 (HO (C 2 H 4 O) 2 H) H + . There are no (MH-H 2 O) + ions or protonated dimer ions (n2, x2) in the spectra of PEGMAE. The Relative Molar Sensitivities (RMS) or the Relative Sensitivity per Gram (RSG) increases linearly with molecular polarizabilty or molecular weight with a non-zero intercept.

En este trabajo se realiza una exploración sobre los textos originales de Lorentz y Poincaré alrededor de la estructura del electrón, con el objetivo de estudiar su estructura y analizar la posibilidad de explicar la naturaleza de su masa como un efecto electrodinámico. Bajo este contexto, se considera al electrón no como una carga puntual, sino como una estructura de simetría esférica de radio diferente de cero. Eneste sentido, surge un modelo sobre el electrón que está en correspondencia con los datos empíricos observados. Por otro lado, en la enseñanza de la física se reconoce abiertamente que se necesita el apoyo de información visual dirigida a los estudiantes, buscando favorecer su comprensión en los fenómenos abordados. Frente a esto es necesario hacer evidente que toda representación es una manera de interpretar y significar los fenómenos del mundo físico.

Editorial handling by R. Fuge a b s t r a c t Lime treatment of acid mine drainage (AMD) generates large volumes of neutralization sludge that are often stored under water covers. The sludge consists mainly of calcite, gypsum and a widespread ferrihydrite-like Fe phase with several associated species of metal(loid) contaminants. The long-term stability of metal(loid)s in this chemically ill-defined material remains unknown. In this study, the stability and speciation of As in AMD sludge subjected to prolonged anoxic conditions is determined. The total As concentration in the sludge is 300 mg kg À1 . In the laboratory, three distinct water cover treatments were imposed on the sludge to induce different redox conditions (100%N 2 , 100%N 2 + glucose, 95%N 2 :5%H 2 ). These treatments were compared against a control of oxidized, water-saturated sludge. Electron micro-probe (EMP) analysis and spatially resolved synchrotron X-ray fluorescence (SXRF) results indicate that As is dominantly associated with Fe in the sludge. In all treatments and throughout the experiment, measured concentrations of dissolved As were less than 5 lg L À1 . Dissolved Mn concentration in the N 2 + glucose treatment increased significantly compared to other treatments. Manganese and As K-edge X-ray absorption near edge structure spectroscopy (XANES) analyses showed that Mn was the redoxactive element in the solid-phase, while As was stable. Arsenic(V) was still the dominant species in all water-covered sludges after 9 months of anoxic treatments. In contrast, Mn(IV) in the original sludge was partially reduced into Mn(II) in all water-covered sludges. The effect was most pronounced in the N 2 + glucose treatment, suggesting microbial reduction. Micro-scale SXRF and XANES analysis of the treated sludge showed that Mn(II) accumulated in areas already enriched in Fe and As. Overall, the study shows that AMD sludges remain stable under prolonged anoxic conditions. External sources of chemical reductants or soluble C were needed to induce lower redox state in the systems, and even under these imposed treatments, only weakly reducing conditions (Mn threshold) developed. The results suggest that As(V) in AMD sludge will remain stable under prolonged anoxic conditions as long as Mn(IV) is present and organic matter accumulation is negligible.

Spectrum simulation is a useful practical and pedagogical tool. Particularly with complex samples or trace constituents, a simulation can help to understand the limits of the technique and the instrument parameters for the optimal measurement. DTSA-II, software for electron probe microanalysis, provides both easy to use and flexible tools for simulating common and less common sample geometries and materials. Analytical models based on ϕ(ρz) curves provide quick simulations of simple samples. Monte Carlo models based on electron and X-ray transport provide more sophisticated models of arbitrarily complex samples. DTSA-II provides a broad range of simulation tools in a framework with many different interchangeable physical models. In addition, DTSA-II provides tools for visualizing, comparing, manipulating, and quantifying simulated and measured spectra.

Saat ini, Bank dan lembaga keuangan merupakan salah satu pelaku terpenting dalam perekonomian sebuah negara. Masyarakat maupun kalangan industri/usaha sangat membutuhkan jasa Bank dan lembaga keuangan lainnya, untuk mendukung dan memperlancar aktivitasnya.

Currently, Portland Cement (PC) is used extensively in the solidification/stabilisation of a wide variety of wastes. In the nuclear industry, low and intermediate level radioactive wastes are encapsulated or immobilised within composite PC cement systems based on high replacement with blast furnace slag or fly ash. However, the high alkalinity of these PC-based systems will corrode reactive metals found in some wastes releasing hydrogen and forming expansive corrosion products. Alternative cement systems could provide a different hydration chemistry, which would allow wastes containing these metals to be encapsulated with lower reactivity. Calcium sulfoaluminate (CSA) cement is one such cement. It combines economy of cost and low emission of CO 2 with rapid strength gain and compatibility with other construction materials. Hydration provides an internal pore solution where the pH is considerably lower than that of PC. The main hydration product, ettringite, can incorporate a number of ions into its crystal structure, making it an ideal candidate for waste immobilisation.

Commercially available generic Superglue (cyanoacrylate glue) can be used as an alternative mounting medium for stained resin-embedded semithin sections. It is colourless and contains a volatile, quick-setting solvent that produces permanent mounts of semithin sections for immediate inspection under the light microscope. Here, we compare the use of cyanoacrylate glue for mounting semithin sections with classical dibutyl phthalate xylene (DPX) in terms of practical usefulness, effectiveness and the quality of the final microscopic image.

Monte Carlo track-structure simulation provides a near accurate description of the passage of charge particle in water as a surrogate for biological tissue. Radiation transport codes and Monte Carlo track-structure codes are widely used in radiation biophysics, dosimetry and microdosimetry, clinical radiotherapy, in space radiation program and accelerator design and research. Over the past decade the number of Monte Carlo track codes simulating a variety of different types of radiations has increased rapidly. In this paper we provide a review of recent progress in the development of particle track simulation for electron, low-energy light ions and finally the recent model development for the low-energy electron cross-sections in liquid water.

The spatial moments of a contaminant plume undergoing bio-attenuation are coupled to the moments of microbial populations effecting that attenuation. In this paper, a scalable inverse method is developed for estimating field-scale Monod parameters such as the maximum microbial growth rate (l max), the contaminant half saturation coefficient (K s), and the contaminant yield coefficient (Y s). The method uses spatial moments that characterize the distribution of dissolved contaminant and active microbial biomass in the aquifer. A finite element model is used to generate hypothetical field-scale data to test the method under both homogeneous and heterogeneous aquifer conditions. Two general cases are examined. In the first, Monod parameters are estimated where it is assumed a microbial population comprised of a single bacterial species is attenuating one contaminant (e.g., an electron donor and an electron acceptor). In a second case, contaminant attenuation is attributed to a microbial consortium comprised of two microbial species, and Monod parameters for both species are estimated. Results indicate the inverse method is only slightly sensitive to aquifer heterogeneity and that estimation errors decrease as the sampling time interval decreases with respect to the groundwater travel time between sample locations. Optimum conditions for applying the scalable inverse method in both space and time are investigated under both homogeneous and heterogeneous aquifer conditions.

Strange stars are one of the possible compact stellar objects that can be formed after a supernova collapse. We consider a model of strange star having an inner core in the color-flavor locked phase surmounted by a crystalline color superconducting layer. These two phases constitute the {\it quarksphere}, which we assume to be the largest and heaviest part of the strange star. The next layer consists of standard nuclear matter forming a ionic crust, hovering on the top of the quarksphere and prevented from falling by a strong dipolar electric field. The dipolar electric field arises because quark matter is confined in the quarksphere by the strong interaction, but electrons can leak outside forming a few hundreds Fermi thick electron layer separating the ionic crust from the underlying quark matter. The ionic matter and the crystalline color superconducting matter constitute two electromagnetically coupled crust layers. We study the torsional oscillations of these two layers. Remark...

Large-scale coupled cluster or coupled electron pair calculations have been carried out for the radicals H CCCH, CF and 2 3 2 2 CCl F, the anions SiC and Si C as well as the corresponding (N21) electron systems. Accurate equilibrium structures 2 4 2 5 are established in all cases. For the adiabatic ionization potential (IP) of CF , the calculations strongly favour the higher ad 3 experimental value (9.0560.01 eV). The photoelectron (PE) spectrum of CCl F is predicted to have a very complex 2 2 vibrational structure; IP (CCl F) is predicted to be 8.22 eV. The PE spectrum of SiC shows some excitation in the n and ad 2 4 4 2 n stretching vibrational modes and the PE spectrum of Si C is dominated by the adiabatic peak.

The dimension of our space outside the boundaries of the atom - the Solar System, gradually decreases to unity. But, the Universe is an n-dimensional continuum filled with a specific form of matter. Consequently, the space-time continuum is closed at the micro and macro levels, since in both cases it is a one-dimensional world. Given the one-electron model of the Universe, we conclude that the Universe is an elementary particle: an electron.

A finite element 2D Monte Carlo approach is used to evaluate the sensitivity of groundwater contaminant discharges to a Damkohler number ω and spatial variability in aquifer hydraulic conductivity, initial microbial biomass concentrations, and electron acceptor/donor concentrations. Bioattenuation is most sensitive to spatial variations in incipient biomass and critical electron donors/acceptors for ω ≥ 1 (i.e., when pore-water residence times are high compared to the time needed for microbial growth or contaminant attenuation). Under these conditions, critical reaction processes can become substrate-limited at multiple locations throughout the aquifer; which in turn increases expected contaminant discharges and their uncertainties at monitored transects. For ω ≤ 0.2, contaminant discharge is not sensitive to incipient biomass variations. Physical heterogeneities expedite plume arrival and delay departure at transects and in turn attenuate peak discharges but do not affect cumulative contaminant discharges. Physical heterogeneities do, however, induce transect mass discharge variances that are bimodal functions of time; the first peak beings consistently higher. A simple stream tube model is invoked to explain the occurrence of peaks in contaminant discharge variance.

Cut-marks on fossil bones and teeth are an important source of evidence in the reconstruction of ancient butchery practices. The analysis of butchery marks has allowed archaeologists to interpret aspects of past subsistence strategies and the behavior of early humans. Recent advances in optical scanning microscopy allow detailed measurements of cut-mark morphology to be undertaken. An example of this technology is the Alicona 3D InfiniteFocus imaging microscope, which has been applied recently to the study of surface modifications on bones and teeth. Three-dimensional models generated by the Alicona microscope have been used to identify cross-sectional features of experimental cut-marks that are characteristic for specific cutting actions (e.g., slicing, chopping, scraping) and different tool types (e.g., metal versus stone tools). More recently, this technology has been applied successfully to the analysis of $500,000 year-old cut-marked animal bones from Boxgrove (U.K.), as well as cannibalized 14,700 cal BP year-old human bones from Gough's Cave (U.K.). This article describes molding methods used to replicate fragile prehistoric bones and teeth, where image quality was adversely affected by specimen translucency and reflectivity. Alicona images generated from molds and casts are often of better quality than those of the original specimen. SCANNING 33: 316-324, 2011. r 2011 Wiley Periodicals, Inc.

Method of the "impurity probes" is shown to may be used in the high-resolution investigation of the electronic structure of valence band in some wide-gap halides. The method is based on the study of the impurity-induced radiative transitions of electrons between crystal valence band and impurity core level under pulsed X-ray excitation.

The first example of the effect of an electric double layer on the reduction of electrochemically generated radical species is reported. The anion radical of methyl 5-(2,4-dichlorophenoxy)-2-nitrobenzoate (pesticide bifenox) is electrochemically reduced in acetonitrile to a phenylhydroxylamine derivative in a process involving three electrons. This heterogeneous reaction is strongly influenced by the concentration and nature of the cation of the indifferent electrolyte. Depending on the type of tetraalkylammonium cation, the redox potential changes by 0.45 V. The kinetic parameters were obtained for five tetraalkylammonium hexafluorophosphate salts. The Frumkin correction, which assumes that the outer Helmholtz plane coincides with the reaction site, was applied to kinetic data of the radical anion reduction. The correction of the apparent rate accounted for the observed effect only in the case of tetramethylammonium salt. The presence of higher tetraalkylammonium homologues causes deviations from the predicted dependence of the electron-transfer rate on the 2 potential of the outer Helmholtz plane. Hence, the nature of the cation of the electrolyte exerts a further effect extending beyond the electrostatic repulsion only. The corrected rate of electron transfer decreases exponentially with increasing size of the alkyl chain of the indifferent electrolyte cation in the order methyl > ethyl > propyl > butyl > hexyl. The rate decay is characterized by an exponent ) 0.83. This confirms that the reaction plane for the reduction of the bifenox radical anion is different for each electrolyte. Due to this fact the Frumkin correction cannot fully account for the observed dependence of the heterogeneous rate on the solution composition. The observed effect is not specific to the bifenox radical. A similar influence of the concentration and nature of the cation of the indifferent electrolyte was observed for other nitro compounds, namely, nitrobenzene, nitrobenzoate, and nitrofen.