A New Sampling Scheme for the Ring Positron Camera: Dichotomic Ring Sampling

A new sampling scheme applicable to the circular ring geometry positron camera is described. The new scheme employs Dichotomic-Ring (two half rings) with linearmotion which allows parallel or fan mode sampling with any desired degree of sampling interval. The parallel and fan data sets obtained by dichotomic motion provide d/4 and d/2 samplings where d is the detector to detector spacing. Computer simulations were made which confirmed the expected performances and results are compared with other conventional schemes such as wobbling and d/2 angular motion sampling schemes for a ring geometry positron camera.     

Evaluation of increased incubation temperature and cefixime-tellurite treatment for the isolation of Escherichia coli O157:H7 from minced beef

To improve enrichment and isolation of Escherichia coli O157:H7, this study evaluated increased incubation temperature and cefixime-tellurite (CT) on five strains of each of the following bacteria, E. coli, Hafnia alvei, Enterobacter spp., Citrobacter freundii and E. coli O157:H7, and two strains of E. coli O157:nH7. These were grown in pure culture in LST broth with varying cefixime-tellurite concentrations. A range of incubation temperatures from 37 to 46 degrees C was investigated for the inhibition of cohabitant microorganisms. Minced beef, spiked with E. coli O157:H7 and cohabitant microorganisms was investigated. Increased incubation temperature (42 degrees C) and treatment with half of the prescribed amount of cefixime-tellurite by BAM for SMAC agar in enrichment step were the most effective in selectively growing E. coli O157:H7. The results show that E. coli O157:H7 is more resistant to these two conditions than the other cohabitant bacteria.     

A neural network-based approach for calculating dissolved oxygen profiles in reservoirs

A Neural Network (NN) modelling approach has been shown to be successful in calculating pseudo steady state time and space dependent Dissolved Oxygen (DO) concentrations in three separate reservoirs with different characteristics using limited number of input variables. The Levenberg–Marquardt algorithm was adopted during training. Pre-processing before training and post processing after simulation steps were the treatments applied to raw data and predictions respectively. Generalisation was improved and over-fitting problems were eliminated: Early stopping method was applied for improving generalisation. The correlation coefficients between neural network estimates and field measurements were as high as 0.98 for two of the reservoirs with experiments that involve double layer neural network structure with 30 neurons within each hidden layer. A simple one layer neural network structure with 11 neurons has yielded comparable and satisfactorily high correlation coefficients for complete data set, and training, validation and test sets of the third reservoir.     

Branched KLVFF tetramers strongly potentiate inhibition of beta-amyloid aggregation

The key pathogenic event in the onset of Alzheimer's disease (AD) is the aggregation of beta-amyloid (Abeta) peptides into toxic aggregates. Molecules that interfere with this process might act as therapeutic agents for the treatment of AD. The amino acid residues 16-20 (KLVFF) are known to be essential for the aggregation of Abeta. In this study, we have used a first-generation dendrimer as a scaffold for the multivalent display of the KLVFF peptide. The effect of four KLVFF peptides attached to the dendrimer (K(4)) on Abeta aggregation was compared to the effect of monomeric KLVFF (K(1)). Our data show that K(4) very effectively inhibits the aggregation of low-molecular-weight and protofibrillar Abeta(1-42) into fibrils, in a concentration-dependent manner, and much more potently than K(1). Moreover, we show that K(4) can lead to the disassembly of existing aggregates. Our data lead us to propose that conjugates that bear multiple copies of KLVFF might be useful as therapeutic agents for the treatment of Alzheimer's disease.     

Three-Dimensional Collagen Type I Matrix Up-Regulates Nuclear Isoforms of the Microtubule Associated Protein Tau Implicated in Resistance to Paclitaxel Therapy in Ovarian Carcinoma

Epithelial ovarian carcinoma is the deadliest gynecologic malignancy. One reason underlying treatment failure is resistance to paclitaxel. Expression of the microtubule associated protein tau has recently been proposed as a predictor of response to paclitaxel in ovarian carcinoma patients. Expression of tau was probed using immunohistochemistry in 312 specimens of primary, and 40 specimens of metastatic, ovarian carcinoma. Serous epithelial ovarian carcinoma cell line models were used to determine the expression of tau by Western blot and immunofluorescence staining. Subcellular fractionation and Western blot were employed to examine nuclear and cytoplasmic localization of tau. Gene silencing and clonogenic assays were used to evaluate paclitaxel response. Tau was expressed in 44% of all tested cases. Among the primary serous epithelial ovarian carcinoma cases, 46% were tau-positive. Among the metastatic serous epithelial ovarian carcinomas, 63% were tau-positive. Cell culture experiments demonstrated that tau was expressed in multiple isoforms. Three-dimensional collagen I matrix culture conditions resulted in up-regulation of tau protein. Silencing of tau with specific siRNAs in a combination with three-dimensional culture conditions led to a significant decrease of the clonogenic ability of cells treated with paclitaxel. The data suggest that reduction of tau expression may sensitize ovarian carcinoma to the paclitaxel treatment.     

Energy distributions and radiation emissions in an inertial electrostatic confinement (IEC) device under low and moderate magnetic fields

The energy distributions and electromagnetic emissions of deuterium ions and electrons in an inertial electrostatic confinement (IEC) unit are reported for low and moderate magnetic field cases. The IEC device has a central wire system inside the grid system of the chamber for the production of the azimuthal magnetic field. The real-time simulations are performed by time integration method by using a finite difference method (FDM) for the physical geometry of device. It is observed that the field induces helical trajectories on the particles especially at the central region where the magnetic force is maximized in a fully ionized Deuterium media. The results prove that the particles have rich dynamics in terms of their trajectories. The effect of negative potential and particle–particle interaction play important roles to determine the trajectories even for low number of ions and electrons. Ion temperatures are calculated as T_i = 6.9 keV after 6 μs for low field case and T_i = 1.517 MeV after 22 μs for medium field case.     

Homozygosity for a Novel DOCK7 Variant Due to Segmental Uniparental Isodisomy of Chromosome 1 Associated with Early Infantile Epileptic Encephalopathy (EIEE) and Cortical Visual Impairment

Early infantile epileptic encephalopathy (EIEE) is a severe neurologic and neurodevelopmental disease that manifests in the first year of life. It shows a high degree of genetic heterogeneity, but the genetic origin is only identified in half of the cases. We report the case of a female child initially diagnosed with Leber congenital amaurosis (LCA), an early-onset retinal dystrophy due to photoreceptor cell degeneration in the retina. The first examination at 9 months of age revealed no reaction to light or objects and showed wandering eye movements. Ophthalmological examination did not show any ocular abnormalities. The patient displayed mildly dysmorphic features and a global developmental delay. Brain MRI demonstrated pontine hypo-/dysplasia. The patient developed myoclonic epileptic seizures and epileptic spasms with focal and generalized epileptiform discharges on electroencephalogram (EEG) at the age of 16 months. Genetic screening for a potentially pathogenic DNA sequence variant by whole-exome sequencing (WES) revealed a novel, conserved, homozygous frameshift variant (c.5391delA, p.(Ala1798LeufsTer59)) in exon 42 of the DOCK7 gene ({"type":"entrez-nucleotide","attrs":{"text":"NM_001271999.1","term_id":"431822374","term_text":"NM_001271999.1"}}NM_001271999.1). Further analysis by SNP array (Karyomapping) showed loss of heterozygosity (LOH) in four segments of chromosome 1. WES data of the parents and the index patient (trio analysis) demonstrated that chromosome 1 was exclusively inherited from the mother. Four LOH segments of chromosome 1 alternately showed isodisomy (UPiD) and heterodisomy (UPhD). In WES data, the father was a noncarrier, and the mother was heterozygous for this DOCK7 variant. The DOCK7 gene is located in 1p31.3, a region situated in one of the four isodisomic segments of chromosome 1, explaining the homozygosity seen in the affected child. Finally, Sanger sequencing confirmed maternal UPiD for the DOCK7 variant. Homozygous or compound heterozygous pathogenic variants in the DOCK7 (dedicator of cytokinesis 7) gene are associated with autosomal recessive, early infantile epileptic encephalopathy 23 (EIEE23; OMIM #615,859), a rare and heterogeneous group of neurodevelopmental disorders diagnosed during early childhood. To our knowledge, this is the first report of segmental uniparental iso- and heterodisomy of chromosome 1, leading to homozygosity of the DOCK7 frameshift variant in the affected patient.     

Entanglement and Sudden Death for a Two-Mode Radiation Field Two Atoms

The effect of the field–field interaction on a cavity containing two qubit (TQ) interacting with a two mode of electromagnetic field as parametric amplifier type is investigated. After performing an appropriate transformation, the constants of motion are calculated. Using the Schrödinger differential equation a system of differential equations was obtained, and the general solution was obtained in the case of exact resonance. Some statistical quantities were calculated and discussed in detail to describe the features of this system. The collapses and revivals phenomena have been discussed in details. The Shannon information entropy has been applied for measuring the degree of entanglement (DE) between the qubits and the electromagnetic field. The normal squeezing for some values of the parameter of the field–field interaction is studied. The results showed that the collapses disappeared after the field–field terms were added and the maximum values of normal squeezing decrease when increasing of the field–field interaction parameter. While the revivals and amplitudes of the oscillations increase when the parameter of the field–field interaction increases. Degree of entanglement is partially more entangled with increasing of the field-field interaction parameter. The relationship between revivals, collapses and the degree of entanglement (Shannon information entropy) was monitored and discussed in the presence and absence of the field–field interaction.     

Effect of thermal damage on mineralogical and strength properties of basic volcanic rocks exposed to high temperatures

Bulletin of Engineering Geology and the Environment - In this study, the engineering behaviors of rocks exposed to temperatures ranging from 200 to 1000 °C were investigated and...     

Determination of optimum Pd:Ni ratio for PdxNi100‐x/CNTs formic acid electrooxidation catalysts synthesized via sodium borohydride reduction method

The main purpose of this study is to investigate the optimum Pd:Ni molar ratio for carbon nanotube–supported PdNi (Pd_xNi_100‐x/CNT) alloy catalysts toward formic acid electrooxidation (FAE). NaBH₄ reduction method was employed for the synthesis of Pd₉₀Ni₁₀/CNT, Pd₇₀Ni₃₀/CNT, Pd₅₀Ni₅₀/CNT, and Pd₄₀Ni₆₀/CNT. Synthesized catalysts were characterized by employing advanced surface analytical techniques, namely, X‐ray diffraction (XRD), transmission electron microscopy (TEM), N₂ adsorption‐desorption, and inductively coupled plasma–mass spectrometry (ICP‐MS). The characterization results showed that all catalysts were successfully synthesized at desired molar composition. Pd₉₀Ni₁₀/CNT displayed the highest specific and mass activities with 2.32 mA/cm² and 613.9 mA/mg Pd, respectively. Specific activity of the Pd₉₀Ni₁₀/CNT was found approximately 3.6, 2.3, 11.1, and 3.4 times higher than those of Pd₇₀Ni₃₀/CNT, Pd₅₀Ni₅₀/CNT, Pd₄₀Ni₆₀/CNT, and Pd/CNT, respectively. The synergistic effect between Pd and Ni at optimized metal ratio was utilized to obtain an improvement in specific activity. Furthermore, Pd₉₀Ni₁₀/CNT showed the lowest charge transfer resistance (R_ct) and a long‐term stability. To our knowledge, this is the first study reporting the optimization of atomic molar composition for Pd_xNi_100‐x/CNT catalysts toward FAE.