Synthesis and Evaluation of Novel Acyclic Nucleoside Phosphonates as Inhibitors of Plasmodium falciparum and Human 6‐Oxopurine Phosphoribosyltransferases

Acyclic nucleoside phosphonates (ANPs) are a promising class of antimalarial therapeutic drug leads that exhibit a wide variety of K_i values for Plasmodium falciparum (Pf) and human hypoxanthine‐guanine‐(xanthine) phosphoribosyltransferases [HG(X)PRTs]. A novel series of ANPs, analogues of previously reported 2‐(phosphonoethoxy)ethyl (PEE) and (R,S)‐3‐hydroxy‐2‐(phosphonomethoxy)propyl (HPMP) derivatives, were designed and synthesized to evaluate their ability to act as inhibitors of these enzymes and to extend our ongoing antimalarial structure–activity relationship studies. In this series, (S)‐3‐hydroxy‐2‐(phosphonoethoxy)propyl (HPEP), (S)‐2‐(phosphonomethoxy)propanoic acid (CPME), or (S)‐2‐(phosphonoethoxy)propanoic acid (CPEE) are the acyclic moieties. Of this group, (S)‐3‐hydroxy‐2‐(phosphonoethoxy)propylguanine (HPEPG) exhibits the highest potency for PfHGXPRT, with a K_i value of 0.1 μM and a K_i value for human HGPRT of 0.6 μM . The crystal structures of HPEPG and HPEPHx (where Hx=hypoxanthine) in complex with human HGPRT were obtained, showing specific interactions with active site residues. Prodrugs for the HPEP and CPEE analogues were synthesized and tested for in vitro antimalarial activity. The lowest IC₅₀ value (22 μM ) in a chloroquine‐resistant strain was observed for the bis‐amidate prodrug of HPEPG.     

How Property Title Impacts Urban Consolidation: A Life Cycle Examination of Multi-title Developments

Continuing urbanisation is triggering an increase in multi-titled housing internationally. This trend has given rise to a substantial research interest in the social consequences of higher density living. Fewer enquiries have been directed to examining how property title subdivisions generate social issues in multi-titled housing. This is a significant gap in the literature, as the tensions inherent in multi-title developments have significant implications for individuals, developments and entire metropolitan areas. This article employs a life cycle framework to examine the profound operational and governance challenges that are associated with the fusion of private lot ownership with common property ownership. The article calls for a more explicit recognition of these challenges by academics, policymakers, practitioners and the broader community.     

On the discriminability of fixed- from variable-stimulus durations.

A discrete-trials procedure was used to measure 6 homing pigeons' ability to discriminate one (fixed) stimulus duration from another (variable) temporal stimulus composed of 12 different durations, ranging from 2.5 to 57.5 sec, with an arithmetic mean of 30 sec. Exposed to a 3-key array, Ss were trained to peck the left key when the center key had been lit for the fixed duration and to peck the right key when the center key had been lit for intervals from the variable-duration set. Across 11 experimental conditions, the fixed duration was varied nonsystematically from 5 to 55 sec in steps of 5 sec. The same set of variable durations was used in each condition. Contrary to a scalar timing model, the indifference point between the fixed and variable durations was not a linear function of the fixed duration. Further, discriminability of the fixed from the variable durations was not symmetric about the arithmetic mean of the variable durations, and response bias was systematically related to the fixed duration. It is concluded that animals' ability to discriminate temporal stimuli is not independent of their response biases when 1 temporal stimulus is made up of a number of different temporal components. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychological and academic adjustment in adopted children.

Evaluated psychological and academic adjustment of 130 6–11 yr old adopted children and 130 age-matched nonadopted children using the Hahnemann Elementary School Behavior Rating Scale and a child behavior profile. Results show that adopted Ss were rated higher in psychological and school-related behavior problems and lower in social competence and school achievement than were nonadopted Ss. It is suggested that although the results support the position that the risk is greater for adopted children to develop emotional and school-related problems, the data should not be overinterpreted because the majority of adopted Ss were within the normal range of behavior. (50 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

More Information From Fewer Questions: The Factor Structure and Item Properties of the Original and Brief Fear of Negative Evaluation Scale.

Statistical methods designed for categorical data were used to perform confirmatory factor analyses and item response theory (IRT) analyses of the Fear of Negative Evaluation scale (FNE; D. Watson & R. Friend, 1969) and the Brief FNE (BFNE; M. R. Leary, 1983). Results suggested that a 2-factor model fit the data better for both the FNE and the BFNE, although the evidence was less strong for the FNE. The IRT analyses indicated that although both measures had items with good discrimination, the FNE items discriminated only at lower levels of the underlying construct, whereas the BFNE items discriminated across a wider range. Convergent validity analyses indicated that the straightforwardly-worded items on each scale had significantly stronger relationships with theoretically related measures than did the reverse-worded items. On the basis of all analyses, usage of the straightforwardly-worded BFNE factor is recommended for the assessment of fear of negative evaluation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of college attendance on locus of control.

Determined the stability of the social-psychological concept of locus of control (LOC) and measured the extent to which LOC changes with the acquisition of postsecondary education. Because measurement errors could affect naive measures of stability and change, the common regression approach was avoided in favor of LISREL, a general method for the analysis of covariance structures that is appropriate for the analysis of panel survey data. Data were obtained from the National Longitudinal Study of the High School Class of 1972, which involved a stratified national probability sample of 22,652 students. The analysis reported here was confined to data on 8,650 White males. Results show that education beyond high school had little or no effect on LOC. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using the elaboration likelihood model to examine online persuasion through website design

To investigate the dynamics of online persuasion, this research uses the Elaboration Likelihood Model (ELM) to determine the effects of argument quality as a central route to influence attitude change versus design and social elements as peripheral routes to attitude change. Additional to this research is an examination of change in issue involvement as a mediator between central and peripheral routes leading to attitude change. Findings from a study involving 403 participants add to our understanding of ELM concerning the role of website design and how an individual’s level of issue involvement is a prerequisite to changing user attitudes.     

The role of instruction and verbalization in improving performance on complex search tasks

This paper examines methods of improving human search performance on a diagnostic task where it does not help to provide computer suggestions about the next enquiry to make. In three experiments it was found (a) that verbal instruction in optimal procedures was ineffective in changing actual performance, although it changed answers to verbal tests of knowledge; (b) that requiring people to say aloud the reasons for each action was ineffective in changing either performance or verbal tests of knowledge; but if people were given both verbal instructions and the requirement to justify each action aloud, performance was improved; (c) this successful training method changed performance not merely on the specific task that was trained, but also on a superficially different search task in which the same general procedures were optimal. These findings suggest that human decision processes change if key information is temporarily activated at the time it is needed, but not if it is merely learned at an irrelevant time. Such a process also explains the beneficial effect of interfaces that provide explanation or the results of inference at key points in the task.     

Metal Injection Molding of PH 13-8 Mo Stainless Steel

Powder metal injection molding has been used for fabrication of near net shape parts from a number of ferrous alloys including carbonyl steels and stainless steels in the 3XX series and PH 17-4. However, no work has been performed to-date on the metal injection molding of PH 13-8 Mo. Because of a special application, this alloy was injection molded and debound using two different methods. Mechanical properties and micro structural analysis of PH 13-8 Mo parts formed using metal injection molding are presented. Differences in mechanical properties, heat treatment response, and microstructure were observed between the different methods used to make the parts.