Targeting CD44, ABCG2 and CD133 markers using aptamers: in silico analysis of CD133 extracellular domain 2 and its aptamer

The application of nucleic acid aptamers for the diagnosis and therapy of cancer stem cells (CSCs) is expanding. The current study truncated and probed various existing aptamers against CSC markers CD44, ABCG2 and CD133 in retinoblastoma (RB) primary cells, cell lines, a breast cancer cell line and MCF7-sphere. Truncated CD44 aptamer retained its specific binding to cancer cells, ABCG2+ve MCF7-spheres and CD133+ve RB cells. Similarly, ABCG2 and CD133 aptamers showed higher affinity to ABCG2+ve, CD133+ve cells than the negative population and cell lines. All aptamers appreciably reduced viability of up to 50% and 32% of the primary RB tumor cells and cell lines, respectively. Colony formation of MCF7, RB cell lines and MCF7-sphere growth were inhibited significantly. Structure prediction, simulation of CD133 extracellular domain 2 (ExD2) and A15 followed by docking to comprehend the potential interaction revealed hydrogen bonds and non bonded interactions between them. This information could be used to improve the A15 aptamer to gain more interactions with CD133. Thus approaches undertaken here can be applied universally for cell-specific targeting, and the aptamers studied against CSC markers deserve further in vivo studies.

In-silico optimisation of two-dimensional high performance liquid chromatography for the determination of Australian methamphetamine seizure samples

In-silico optimisation of a two-dimensional high performance liquid chromatography (2D-HPLC) separation protocol has been developed for the interogation of methamphetamine samples including model, real world seizure, and laboratory synthesised samples. The protocol used Drylab® software to rapidly identify the optimum separation conditions from a library of chromatography columns. The optimum separation space was provided by the Phenomonex Kinetex PFP column (first dimension) and an Agilent Poroshell 120 EC-C18 column (second dimension). To facilitate a rapid 2D-HPLC analysis the particle packed C18 column was replaced with a Phenomenex Onyx Monolithic C18 withought sacrificing separation performance. The Drylab® optimised and experimental separations matched very closely, highlighting the robust nature of HPLC simulations. The chemical information gained from an intermediate methamphetamine sample was significant and complimented that generated from a pure seizure sample. The influence of the two-dimensional separation on the analytical figures of merit was also investigated. The limits of detection for key analytes in the second dimension determined for methamphetamine (4.59 × 10-⁴ M), pseudoephedrine (4.03 × 10-4 M), caffeine (5.16 × 10-⁴ M), aspirin (9.32 × 10-4 M), paracetamol (5.93 × 10-4 M) and procaine (2.02 × 10-3 M).

Child abuse investigation: an in depth analysis of how police officers perceive and cope with daily work challenges

Purpose: The purpose of the current study was two-fold: to explore police officers' perceptions of the daily challenges involved in child abuse investigation and how those challenges affect their ability to undertake child abuse investigations, and to explore how these challenges are managed on a daily basis. Design/methodology/approach: This study employed a qualitative research design. In-depth interviews were conducted with a diverse sample of 25 police officers working in child abuse units across three Australian states. Findings: Inductive thematic analysis revealed that heavy caseload and collaboration with other professional groups are two key sources of negative work stress frequently associated with child abuse investigation. Further, despite the provision of organisational strategies aimed at reducing work stress, the officers tended to rely predominantly on informal coping mechanisms.  Research limitations/implications: This study has raised many questions for further research aimed at developing interventions to assist police organisations in managing work stress. Originality/value: This paper provides an in-depth analysis of the key challenges associated with child abuse investigation and the coping mechanisms employed for overcoming these challenges from the unique perspective of police officers authorised to investigate child abuse.

The robust result in meta-analysis of aid effectiveness : a response to Mekasha and Tarp

In this response to Mekasha and Tarp (2013) we show that contrary to what they state, their study validates our basic analysis. They confirm that the literature finds that aid is of little economic importance in generating growth. The results also show that the literature systematically selects control variables for their effect on aid effectiveness. We argue that their choice of the random effects model is not appropriate for the problem at hand, and that the way they use multiple meta-regression analysis contradicts the robust results reached at the basic analysis.

Improving quantification using curtain flow chromatography columns in the analysis of labile compounds: a study on amino acids.

The performance of curtain flow chromatography column technology with MS detection was evaluated for the analysis of labile compounds. The curtain flow column design allows for separations that are faster and/or more sensitive than conventional columns, depending on how exactly the curtain flow column is configured. For example, when mass spectral detection is employed, the curtain flow column can yield separations that are 5-times faster than conventional columns when the curtain flow and the conventional columns have the same internal diameter. Or when the internal diameter of the conventional column is reduced in order to yield the same analytical through-put as the curtain flow column, the sensitivity on the curtain flow column can be as much as 66-fold higher than the conventional column. As a consequence of the higher analytical through-put less standardization is required in the analysis of labile compounds because less sample degradation is apparent. Consequently the sample integrity is preserved yielding data of a higher quality.

The relationship between suicide and violence in schizophrenia: analysis of the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) dataset

Background

Suicide and violence often co-occur in the general population as well as in mentally ill individuals. Few studies, however, have assessed whether these suicidal behaviors are predictive of violence risk in mental illness.

Aims

The aim of this study is to investigate whether suicidal behaviors, including suicidal ideation, threats, and attempts, are significantly associated with increased violence risk in individuals with schizophrenia.

Method

Data for these analyses were obtained from the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) trial, a randomized controlled trial of antipsychotic medication in 1460 adults with schizophrenia. Univariate Cox regression analyses were used to calculate hazard ratios (HRs) for suicidal ideation, threats, and attempts. Multivariate analyses were conducted to adjust for common confounding factors, including: age, alcohol or drug misuse, major depression, antisocial personality disorder, depression, hostility, positive symptom, and poor impulse control scores. Tests of discrimination, calibration, and reclassification assessed the incremental predictive validity of suicidal behaviors for the prediction of violence risk.

Results

Suicidal threats and attempts were significantly associated with violence in both males and females with schizophrenia with little change following adjustment for common confounders. Only suicidal threats, however, were associated with a significant increase in incremental validity beyond age, diagnosis with a comorbid substance use disorder, and recent violent behavior.

Conclusions

Suicidal threats are independently associated with violence risk in both males and females with schizophrenia, and may improve violence risk prediction.

Antifungal synergy of theaflavin and epicatechin combinations against Candida albicans

New antifungal agents are required to compensate for the increase in resistance to standard antifungal agents of Candida albicans, which is an important opportunistic fungal pathogen that causes minor infections in many individuals but very serious infections in those who are immune-compromised. In this study, combinations of theaflavin and epicatechin are investigated as potential antifungal agents and also to establish whether antifungal synergy exists between these two readily accessible and cost-effective polyphenols isolated from black and green tea. The results of disc diffusion assays showed stronger antibacterial activity of theaflavin:epicatechin combinations against C. albicans NCTC 3255 and NCTC 3179, than that of theaflavin alone. Minimum inhibitory concentrations (MICs) of 1,024 μg/ml with theaflavin and 128-256 μg/ml with theaflavin:epicatechin combinations were found. The fractional inhibitory concentration indexes were calculated, and the synergy between theaflavin and epicatechin against both isolates of C. albicans was confirmed. Theaflavin:epicatechin combinations show real potential for future use as a treatment for infections caused by C. albicans.

Growth inhibition of Candida species and Aspergillus fumigatus by statins

Statins are a class of drugs widely used for lowering high cholesterol levels through their action on 3-hydroxy-3-methylglutaryl-CoA reductase, a key enzyme in the synthesis of cholesterol. We studied the effects of two major statins, simvastatin and atorvastatin, on five Candida species and Aspergillus fumigatus. The statins strongly inhibited the growth of all species, except Candida krusei. Supplementation of Candida albicans and A. fumigatus with ergosterol or cholesterol in aerobic culture led to substantial recovery from the inhibition by statins, suggesting specificity of statins for the mevalonate synthesis pathway. Our findings suggest that the statins could have utility as antifungal agents and that fungal colonization could be affected in those on statin therapy.

Conceptions of teaching with integrity online in higher education: a case in the field of engineering

The viewpoints of academic teaching staff take centre stage in the analysis of the changing conceptions of what it means to act with integrity when teaching online. To teach with integrity in contemporary online-supported environments in higher education is not necessarily to teach the same as if one would in teaching regularly face-to-face in the classroom. The paper argues that to teach with integrity online is to teach differently. With integrity both enhanced and in some respects diminished in teaching online, the apparent contradiction can only be resolved through developing conceptions of what teaching with integrity means in the contemporary world of higher education. Implications are drawn in the context of teaching extended and wholly online units in the field of engineering.

Performance analysis of interconnection networks for multi-cluster systems

With the current popularity of cluster computing systems, it is increasingly important to understand the capabilities and potential performance of various interconnection networks. In this paper, we propose an analytical model for studying the capabilities and potential performance of interconnection networks for multi-cluster systems. The model takes into account stochastic quantities as well as network heterogeneity in bandwidth and latency in each cluster. Also, blocking and non-blocking network architecture model is proposed and are used in performance analysis of the system. The model is validated by constructing a set of simulators to simulate different types of clusters, and by comparing the modeled results with the simulated ones.

Performance analysis of heterogeneous multi-cluster systems

When building a cost-effective high-performance parallel processing system, a performance model is a useful tool for exploring the design space and examining various parameters. However, performance analysis in such systems has proven to be a challenging task that requires the innovative performance analysis tools and methods to keep up with the rapid evolution and ever increasing complexity of such systems. To this end, we propose an analytical model for heterogeneous multi-cluster systems. The model takes into account stochastic quantities as well as network heterogeneity in bandwidth and latency in each cluster. Also, blocking and non-blocking network architecture model is proposed and are used in performance analysis of the system. The message latency is used as the primary performance metric. The model is validated by constructing a set of simulators to simulate different types of clusters, and by comparing the modeled results with the simulated ones.

Probing the flexibility of the DsbA oxidoreductase from Vibrio cholerae - a 15N -1H heteronuclear NMR relaxation analysis of oxidised and reduced forms of DsbA

We have determined the structure of the reduced form of the DsbA oxidoreductase from Vibrio cholerae. The reduced structure shows a high level of similarity to the crystal structure of the oxidized form and is typical of this class of enzyme containing a thioredoxin domain with an inserted α-helical domain. Proteolytic and thermal stability measurements show that the reduced form of DsbA is considerably more stable than the oxidized form. NMR relaxation data have been collected and analyzed using a model-free approach to probe the dynamics of the reduced and oxidized states of DsbA. Akaike's information criteria have been applied both in the selection of the model-free models and the diffusion tensors that describe the global motions of each redox form. Analysis of the dynamics reveals that the oxidized protein shows increased disorder on the pico- to nanosecond and micro- to millisecond timescale. Many significant changes in dynamics are located either close to the active site or at the insertion points between the domains. In addition, analysis of the diffusion data shows there is a clear difference in the degree of interdomain movement between oxidized and reduced DsbA with the oxidized form being the more rigid. Principal components analysis has been employed to indicate possible concerted movements in the DsbA structure, which suggests that the modeled interdomain motions affect the catalytic cleft of the enzyme. Taken together, these data provide compelling evidence of a role for dynamics in the catalytic cycle of DsbA.