2,366 research outputs found
Screening Effects on Nonrelativistic Bremsstrahlung in the Scattering of Electrons by Neutral Atoms
Atomic screening effects on nonrelativistic electron-atom bremsstrahlung radiation are investigated using a simple analytic solution of the Thomas-Fermi model for many-electron atoms. The Born approximation is assumed for the initial and final states of the projectile electron. The results show that the screening effect is important in the soft radiation region and is decreasing with increasing radiation. These results help provide correct information about the behavior of bound electrons in the target atom in bremsstrahlung processes
Plasmonic colloidal nanoparticles with open eccentric cavities via acid-induced chemical transformation
Surface-enhanced Raman spectroscopy (SERS) has been considered a promising technique for the detection of trace molecules in biomedicine and environmental monitoring. The ideal metal nanoparticles for SERS must not only fulfill important requirements such as high near-field enhancement and a tunable far-field response but also overcome the diffusion limitation at extremely lower concentrations of a target material. Here, we introduce a novel method to produce gold nanoparticles with open eccentric cavities by selectively adapting the structure of non-plasmonic nanoparticles via acid-mediated surface replacement. Copper oxide nanoparticles with open eccentric cavities are first prepared using a microwave-irradiation-assisted surfactant-free hydrothermal reaction and are then transformed into gold nanoparticles by an acidic gold precursor while maintaining their original structure. Because of the strong near-field enhancement occurring at the mouth of the open cavities and the very rough surfaces resulting from the uniformly covered hyperbranched sharp multi-tips and the free access of SERS molecules inside of the nanoparticles without diffusion limitation, adenine, one of the four bases in DNA, in an extremely diluted aqueous solution (1.0 pM) was successfully detected with excellent reproducibility upon laser excitation with a 785-nm wavelength. The gold nanoparticles with open eccentric cavities provide a powerful platform for the detection of ultra-trace analytes in an aqueous solution within near-infrared wavelengths, which is essential for highly sensitive, reliable and direct in vivo analysis.None1132sciescopu
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Understanding the catalytic chemisorption of the cyanogen chloride via breakthrough curve and genetic algorithm
This study investigated the catalytic chemisorption of cyanogen chloride(CK) with a metal(ASZM) – triethylenediamine(TEDA) complex. XPS data, IR spectra, and DFT calculations demonstrated that the synergetic catalytic hydrolysis of CK by ASZM-TEDA is kinetically favorable, with the enhanced reactivity of water on the catalyst as the primary cause for the accelerated catalytic hydrolysis. To validate the results, ASZM-TEDA was impregnated into activated carbon beads to form a packed-bed reactor for this breakthrough experiment. The proposed species-transport equation parameters were fitted using the genetic algorithm, and the correlation between parameters was compared. The study concludes that TEDA can affect the diffusivity for overall mass transfer-related reactions and accelerate the catalytic reaction of metal with CK. This study is the first to describe chemisorbed breakthrough with catalyst reaction in-depth and provides insights into the optimized ratio between TEDA and metal complexes. This methodology can be applied to various breakthrough experiments with chemical reactions
Genome shotgun sequencing and development of microsatellite markers for gerbera (Gerbera hybrida H.) by 454 GS-FLX
The objective of this research was to develop and characterize microsatellite markers for gerbera. We used shotgun sequencing with Roche 454 GS-FLX Titanium technology to identify microsatellite loci in gerbera genomic DNA (Gerbera hybrida). The total length of non-redundant sequences obtained was 22,527,019 bp, which consisted of 3,085 contigs and 28,249 singletons. We assembled 61,958 reads into 3,085 contigs, of which 114 (3.70%) contained microsatellite repeats. The average G+C content was 39.3%. Functional annotation to known sequences yielded 14.7% unigenes in the ‘Raon’ cultivar. Analysis of the gerbera genome DNA (‘Raon’) general library showed that sequences of (AT), (AG), (AAG) and (AAT) repeats appeared most often, whereas (AC), (AAC) and (ACC) were the least frequent. Primer pairs were designed for 80 loci. Only eight primer pairs produced reproducible polymorphic bands in the 28 gerbera accessions analyzed. A total of 30 alleles were identified from the eight polymorphic SSR loci, with two to eight alleles per locus (average level of 3.75). These markers will be useful for investigating genetic diversity and differentiation in gerbera. Keywords: Genetic diversity, genomics, microsatellite isolation, pyrosequencing, SSRs. African Journal of Biotechnology Vol. 11(29), pp. 7388-7396, 10 April, 201
Fabry nephropathy before and after enzyme replacement therapy: important role of renal biopsy in patients with Fabry disease
Background In Fabry disease, the presence of globotriaosylceramide (GL3) deposits in various kidney cells leads to progressive renal dysfunction. However, kidney biopsy studies in patients with Fabry disease are limited. In the present study, the pathologic findings of patients with Fabry nephropathy receiving enzyme replacement therapy (ERT) and untreated patients without albuminuria were investigated. Methods The present study included 15 patients with Fabry disease who underwent renal biopsy while receiving ERT (group 1: n = 9, age 19–58 years, two males and seven females) or before ERT initiation (group 2: n = 6, age 11–66 years, one male and five females). All patients in group 2 were normoalbuminuric. Results Group 1 showed improved clinical symptoms, such as acroparesthesia. The ERT duration was 1.2 to 8 years and seven of the nine patients showed GL3 deposits in various kidney cells and segmental foot process effacement (FPE) of podocytes. GL3 deposits and FPE were not observed in the two remaining patients in group 1. Group 2 showed segmental FPE and podocyte GL3 deposits. Most patients in group 2 also showed GL3 deposits in the mesangium, endothelium, or tubular epithelium. Conclusion The study results showed that segmental FPE and GL3 deposits can persist in Fabry nephropathy despite ERT. In addition, segmental FPE and GL3 deposits were observed in various kidney cells in normoalbuminuric patients with Fabry disease. These findings indicated that kidney biopsies at baseline and follow-up evaluation of Fabry nephropathy are essential for timely ERT initiation and ERT response assessment
Frontal lobe epilepsy: Clinical characteristics, surgical outcomes and diagnostic modalities
SummaryObjectiveTo identify surgical prognostic factors and to characterize clinical features according to the location of the intracranial ictal onset zone of frontal lobe epilepsy (FLE) in order to assess the role of various diagnostic modalities, including concordances with presurgical evaluations.MethodsWe studied 71 FLE patients who underwent epilepsy surgery and whose outcomes were followed for more than 2 years. Diagnoses were established by standard presurgical evaluation.ResultsClinical manifestations could be categorized into six types: initial focal motor (9 patients), initial versive seizure (15), frontal lobe complex partial seizure (14), complex partial seizure mimicking temporal lobe epilepsy (18), initial tonic elevation of arms (11), and sudden secondary generalized tonic–clonic seizure (4). Thirty-seven patients became seizure-free after surgery. Five patients were deleted in the analysis because of incomplete resection of ictal onset zones. The positive predictive value of interictal EEG, ictal EEG, MRI, PET, and ictal SPECT, respectively were 62.5%, 56.4%, 73.9%, 63.2%, and 63.6%, and the negative predictive value were 46.0%, 44.4%, 53.5%, 44.7%, and 51.7%. No significant relationship was found between the diagnostic accuracy of these modalities and surgical outcome, with the exception of MRI (p=0.029). Significant concordance of two or more modalities was observed in patients who became seizure-free (p=0.011). We could not find any clinical characteristic related to surgical outcome besides seizure frequency. No definite relationship was found between the location of intracranial ictal onset zone and clinical semiology.ConclusionAlthough various diagnostic methods can be useful in the diagnosis of FLE, only MRI can predict surgical outcome. Concordance between presurgical evaluations indicates a better surgical outcome
Nucleation and growth of platelets in hydrogen-ion-implanted silicon
H ion implantation into crystalline Si is known to result in the precipitation of planar defects in the form of platelets. Hydrogen-platelet formation is critical to the process that allows controlled cleavage of Si along the plane of the platelets and subsequent transfer and integration of thinly sliced Si with other substrates. Here we show that H-platelet formation is controlled by the depth of the radiation-induced damage and then develop a model that considers the influence of stress to correctly predict platelet orientation and the depth at which platelet nucleation density is a maximum.This work was supported
by the U.S. Department of Energy, Office of Basic
Energy Sciences
Gamma oscillation in functional brain networks is involved in the spontaneous remission of depressive behavior induced by chronic restraint stress in mice
Additional file 1: Table S1. Statistical results of the cross-correlation in Fig. 2c
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