Gamma Uranium Molybdenum Alloy: Its Hydride and Performance

The high density metastable gamma uranium molybdenum alloy (γ‐UMo) is being qualified as a nuclear fuel for the conversion of high enriched uranium (HEU) to low enriched uranium (LEU) fuels in research nuclear reactors. γ‐UMo, with compositions between 7 and 10 wt.% molybdenum, has excellent properties to allocate fission gases but unacceptable behavior in contact with aluminum in the matrix of dispersed fuels. Development and processing alternatives are welcome to decide final working paths and new nuclear fuels design. A historical introduction on the development of materials testing reactors (MTR) nuclear fuels is presented to illustrate comings and goings to reach desired qualification objectives. Several studies performed on UMo probes, miniplates and full size plates are mentioned to contribute to the knowledge of fuel properties and to incorporate new process technologies. Focus is directed to the discovery of the gamma uranium molybdenum hydride and the hot rolling colamination of monolithic UMo with nonaluminum claddings. A scalable process of hydriding, milling and dehydriding (HMD) to comminute the ductile UMo was developed. Monolithic UMo miniplates with Zircaloy‐4 (Zry4) cladding was colaminated for the first time and under irradiation conditions showed excellent performance after high burn‐up

Tissue location of resistance in apple to the rosy apple aphid established by electrical penetration graphs

A study of the constitutive resistance of the apple cultivar Florina, Malus domestica Borkh. (Rosaceae), to the rosy apple aphid, Dysaphis plantaginea (Passerini) (Homoptera Aphididae), was performed for the first time by the electrical penetration graph (DC-EPG) system, using the susceptible apple cultivar Smoothe as control. All experiments were conducted with apterous adult virginoparae. The results showed a constitutive resistance in Florina due to a much longer period before the first probe reflecting surface factors. Some weak indications were found for pre-phloem resistance and initiating phloem access was not affected as inferred from equal time to show phloem salivation. However, the complete absence of phloem ingestion indicates a major resistance factor in the phloem sieve elements, most likely in the sieve element sap. Surface factors could have affected tissue related variables and this should be studied further. Anyhow, the strong constitutive resistance in Florina, either on the surface alone or in the phloem as well, effectively prevented reliable experiments on induced resistance, previously detected by molecular methods

Functional Brain Connectivity and Inhibitory Control in Older Adults: A Preliminary Study

According to the inhibition deficit hypothesis, the ability to inhibit unwanted or irrelevant thoughts and behaviors decreases with age, which can have a significant impact on cognitive and emotional processing. However, studies examining inhibition and age have shown mixed results, with some studies finding a decrease in inhibitory control as individuals age, while others have found no relationship. The goal of this proof-of-concept study was to examine the underlying neural mechanisms that may explain why some older adults are better than others at inhibitory control by investigating the relationship between resting-state functional connectivity (rsFC) of the salience network, a network critical for detecting and focusing attention toward relevant stimuli while ignoring irrelevant information in the environment, and a behavioral measure of inhibitory control (Stroop Task interference score) in a sample of 65 healthy older individuals (ages 65+). Results revealed no direct effect of age on Stroop performance; however, there was an indirect effect of age on Stroop performance through rsFC. These results suggest that rsFC of the salience network may be an important factor to consider when it comes to understanding individual differences in inhibitory control behavior among older adults

Response of female Cydia molesta (Lepidoptera: Tortricidae) to plant derived volatiles

Peach shoot volatiles were attractive to mated female oriental fruit moth, Cydia molesta (Busck), in a dual choice arena. No preference was observed between leaf odours from the principle host plant, peach, and the secondary host plant, apple. Twenty-two compounds were identified in headspace volatiles of peach shoots using gas chromatography-mass spectrometry. Green leaf volatiles accounted for more than 50% of the total emitted volatiles. A bioassay-assisted fractionation using different sorbent polymers indicated an attractant effect of compounds with a chain length of 6-8 carbon atoms. The major compounds of this fraction were tested either singly or in combinations for behavioural response of females. Significant bioactivity was found for a three-component mixture of (Z)-3-hexen-1-yl acetate, (Z)-3-hexen-1-ol and benzaldehyde in a 4:1:1 ratio. This synthetic mixture elicited a similar attractant effect as the full natural blend from peach shoots as well as the bioactive fractio

The effect of ultrasonic access cavity preparation on dentinal inner walls: a micro-CT study on cadaveric samples

ObjectiveThe objective of this study is to evaluate the occurrence of coronal dentinal micro-cracks after access cavity refinement using high-speed burs and ultrasonic tips by means of micro-computed tomography (micro-CT) analysis.MethodsIn this study, 18 mandibular cadaveric incisors were divided into two groups according to the protocol of the preparation of the conventional access cavity. The diamond bur 802 # 12 was used until the perforation of the pulp roof. Then, the Endo-Z bur was used for the group #1 and the ultrasonic tip Start-X # 1 for the group #2 to finish and refine the access cavity. The preparation time of each access cavity has been recorded. The teeth underwent a micro-CT scan before and after the preparation of the access cavity. Fisher's exact test, the Chi-square test, the Kolmogorov-Smirnov test, the Mann-Whitney test, and the Student's test were used for statistical evaluation.ResultsThe percentage of teeth with new micro-cracks is not significantly different between the two groups (-p-value < 0.5). The number of newly formed micro-cracks and extension size were not significantly different between the two groups. The direction of extension of the micro- cracks was occluso-apical. The average duration of the access cavity is significantly smaller with the Endo-Z system (-p- value < 0.001). The roughness of walls surfaces has no statistically difference between the two groups.ConclusionThe use of ultrasound, although slower, is considered safe in the creation of dentinal micro-cracks, in the preparation of the access cavity