Pharmacokinetic Factors in the Neurotoxicities of <i>p</i>-Bromophenylacetylurea and <i>m</i>-Dinitrobenzene.

Conventional approaches to the study of neurotoxicants focus exclusively on the direct action of neurotoxicants on the nervous system. In fact, pharmacokinetic and metabolic factors can greatly modify the effect of neurotoxicants. This thesis presents the investigations of the pharmacokinetic and metabolic factors in chemical-induced neurotoxicities, p-Bromophenylacetylurea (BPAU) and m-dinitrobenzene (m-DNB) were selected as model neurotoxicants. Wistar (LACP) and F344 rats, and the analytical techniques of HPLC, MS and NMR were used in the present studies. This study has demonstrated that metabolism and pharmacokinetic behaviour of BPAU and m-DNB significantly modified their neurotoxicity. Three metabolites of BPAU, 3-hydroxy-5-(4-bromophenyl)-1,3 -diazapentane-2,4-dione (M1), 4-4-bromo-phenyl)-3-oxapyrrolidine-2,5-dione (M2) and 3-methyl-5-(4-bromophenyl)-1,3-diaza- pentane-2,4-dione (M3), were identified and characterised in this study. Phenylmethanesulfonyl fluoride (PMSF) which can intensify BPAU-induced neuropathy signiflcandy delayed BPAU elimination, increased M1 levels in tissues and decreased M2 concentration in serum This metabolic interaction and neurotoxic synergy between the two compounds represent a distinct model in the mechanistic studies of the promotion of delayed neuropathy. The present study also showed that 1-year old rats which are more susceptible to BPAU-induced neuropathy produced more M1 and less M2 than 6-week old rats. In vivo and in vitro studies in this thesis also demonstrated that m-DNB can be metabolised in brain. The major metabolite was 3-nitroaniline (3-NA). An activated intermediate, 3-nitrosonitrobenzene (3-NNB) was detected in the cultured astrocytes and endothelial cells. This suggests that metabolic activation may play an important role in m-DNB-induced neurotoxicity. The infusion-lesion model revealed that once a concentration threshold for m-DNB is exceeded, the time which m-DNB is maintained above that threshold is a more important factor in producing brain lesions than a higher transient concentration. This study has demonstrated that pharmacokinetic approaches have a great potential in understanding chemical-induced neurotoxicity

Robust charge and magnetic order under electric field and current in the multiferroic LuFe(2)O(4)

We performed elastic neutron scattering measurements on the charge- and magnetically-ordered multiferroic material LuFe(2)O(4). An external electric field along the [001] direction with strength up to 20 kV/cm applied at low temperature (~100 K) does not affect either the charge or magnetic structure. At higher temperatures (~360 K), before the transition to three-dimensional charge-ordered state, the resistivity of the sample is low, and an electric current was applied instead. A reduction of the charge and magnetic peak intensities occurs when the sample is cooled under a constant electric current. However, after calibrating the real sample temperature using its own resistance-temperature curve, we show that the actual sample temperature is higher than the thermometer readings, and the "intensity reduction" is entirely due to internal sample heating by the applied current. Our results suggest that the charge and magnetic orders in LuFe(2)O(4) are unaffected by the application of external electric field/current, and previously observed electric field/current effects can be naturally explained by internal sample heating.Comment: Version as appeared in PRB

Case History on Prevention of the Landslide at Luoyiqi by Means of Rigid Frame Retaining Structure

This paper presents a new special type of retaining structure which prevents the large-scale landslide. It is named the rigid frame retaining structure. The author in this paper proposed a new computation method, i.e., analysis of the rigid frame within elastic foundation. The new formulations have been performed according to E. Ninkler\u27s theory and the difference principle and with the help of fundamental knowledge of strength of material and matrix algebra. The descriptions of the design and construction of the rigid frame retaining structure were given

Magnetic field induced enhancement of spin-order peak intensity in La(1.875)Ba(0.125)CuO(4)

We report on neutron-scattering results on the impact of a magnetic field on stripe order in the cuprate La$_{1.875}$Ba$_{0.125}$CuO$_4$. It is found that a 7 T magnetic field applied along the {\it c} axis causes a small but finite enhancement of the spin-order peak intensity and has no observable effect on the peak width. Inelastic neutron-scattering measurements indicate that the low-energy magnetic excitations are not affected by the field, within experimental error. In particular, the small energy gap that was recently reported is still present at low temperature in the applied field. In addition, we find that the spin-correlation length along the antiferromagnetic stripes is greater than that perpendicular to them.Comment: 4 pages, 5 figure

Evaluating Two Hands-On Tools for Teaching Local Area Network Vulnerabilities

According to the Verizon’s Data Breach Investigations Report, Local Area Network (LAN) access is the top vector for insider threats and misuses. It is critical for students to learn these vulnerabilities, understand the mechanisms of exploits, and know the countermeasures. The department of Computer Science at North Carolina A&T State University designed two different educational tools that help students learn ARP Spoofing Attacks, which is the most popular attack on LAN. The first tool, called Hacker’s Graphical User Interface (HGUI), is a visualization tool that demonstrates ARP Spoofing Attack with real time animation. The second tool is a hands-on (HandsOn) tool that asks students to perform an ARP Spoofing Attack by manually creating ARP reply packets. It was demonstrated in previous research that both tools enhanced students’ learning. In this paper, we are going to scientifically evaluate and compare the effectiveness of these two tools. We divided the class of forty-five students randomly into two groups. Group A was assigned HGUI lab and the Group B was assigned the HandsOn lab. The labs were assigned as a one and half week homework assignments. Both groups were given a pre-survey and a pre-quiz before the lab. After they submitted the lab, we gave them a post-survey and a post quiz. The analysis shows that prior to the labs, students in both groups have almost identical background in the knowledge of ARP Spoofing. After the lab, both groups made statistically significant improvements. Although group A did better on survey and group B did better on quiz, it is not statistically significant enough to draw a definitive conclusion according to the student’s t-test result. Also, in analyzing survey results, we found that actively reading cyber security related articles is a more significant contributing factor in students’ knowledge in the subject matter than other factors including having formal training or taking cyber security classes