In vitro activity of certain drugs in combination with plant extracts against Staphylococcus aureus infections

This study has been done to evaluate the interaction between ethanolic extracts of Rhus coriaria (leaf), Psidium guajava (Leaf), Lawsonia inermis (Leaf), and Sacropoterium spinosum (seed) and antimicrobialdrugs including oxytetracyclin HCl, enrofloxacin, gentamicin sulphate, and sulphadimethoxin against 4 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). This evaluation was done by well-diffusion method. Results of this study showed that crude extracts from these plants increase the inhibition zones of oxytetracyclin HCl, gentamicin sulphate, and sulphadimethoxin, while combination between the plant extracts and enrofloxacin decreases inhibition zone

Examining the moderating effect of individual-level cultural values on users’ acceptance of E-learning in developing countries: a structural equation modeling of an extended technology acceptance model

In this study, we examine the effects of individual-level culture on the adoption and acceptance of e-learning tools by students in Lebanon using a theoretical framework based on the Technology Acceptance Model (TAM). To overcome possible limitations of using TAM in developing countries, we extend TAM to include subjective norms (SN) and quality of work life constructs as additional constructs and a number of cultural variables as moderators. The four cultural dimensions of masculinity/femininity (MF), individualism/collectivism, power distance and uncertainty avoidance were measured at the individual level to enable them to be integrated into the extended TAM as moderators and a research model was developed based on previous literature. To test the hypothesised model, data were collected from 569 undergraduate and postgraduate students using e-learning tools in Lebanon via questionnaire. The collected data were analysed using the structural equation modelling technique in conjunction with multi-group analysis. As hypothesised, the results of the study revealed perceived usefulness (PU), perceived ease of use (PEOU), SN and quality of work life to be significant determinants of students’ behavioural intention (BI) towards e-learning. The empirical results also demonstrated that the relationship between SN and BI was particularly sensitive to differences in individual-cultural values, with significant moderating effects observed for all four of the cultural dimensions studied. Some moderating effects of culture were also found for both PU and PEOU, however, contrary to expectations the effect of quality of work life was not found to be moderated by MF as some previous authors have predicted. The implications of these results to both theory and practice are explored in the paper

Lifespan profiles of Alzheimer's disease–associated genes and their products in monkeys and mice.

Alzheimer's disease (AD) is characterized by plaques of amyloid–beta (Aβ) peptide, cleaved from amyloid–β precursor protein (AβPP). Our hypothesis is that lifespan profiles of AD-associated mRNA and protein levels in monkeys would differ from mice, and that differential lifespan expression profiles would be useful to understand human AD pathogenesis. We compared profiles of AβPP mRNA, AβPP protein, and Aβ levels in rodents and primates. We also tracked a transcriptional regulator of the AβPP gene, specificity protein 1 (SP1), and the β amyloid precursor cleaving enzyme (BACE1). In mice, AβPP and Sp1 mRNA and their protein products were elevated late in life; Aβ levels declined in old age. In monkeys, Sp1, AβPP, and BACE1 mRNA declined in old age, while protein products and Aβ levels rose. Proteolytic processing in both species did not match production of Aβ. In primates, AβPP and Sp1 mRNA levels coordinate, but an inverse relationship exists with corresponding protein products, as well as Aβ levels. Comparison of human DNA and mRNA sequences to monkey and mouse counterparts revealed structural features that may explain differences in transcriptional and translational processing. These findings are important for selecting appropriate models for AD and other age–related diseases

Occurrence and molecular characterization of Salmonella Typhimurium and Salmonella Enteritidis isolates from contaminated food samples from Palestine

Salmonella is one of the most frequently isolated foodborne pathogens. It is of major public health concern worldwide. Poultry meat and eggs represent an important source of Salmonellae organism for consumer health. This study aimed to evaluate the occurrence of Salmonella enterica serotype Typhimurium and Enteritidis using multiplex PCR (mPCR) among isolates collected from the local market and to assess genetic relationships between isolates of S. Typhimurium, which was the only serotype isolated from the tested food samples. This was done using virulence factors profiling and fingerprint profiling by random amplified polymorphic DNA (RAPD-PCR) and repetitive sequence PCR (REP-PCR) using enterobacterial repetitive intergenic consensus (ERIC-PCR) and interspersed repetitive DNA sequence BOXAIR-PCR. The overall occurrence percentage of S. Typhimurium and S. Enteritidis out of 51 isolates was 54.9% and 0.0%, respectively. Only 13 out of 17 virulence genes were detected in these isolates. The occurrence of the detected virulence genes among these isolates was 100%, 50.0%,46.4%, 39.3%, 35.7%, 35.7%, 32.1%, 25.0%, 25.0%, 17.6%, 14.3%, 14.3%, 3.6% for invA, sopB, prgH, sitC, pefA, tolC, cdtB, msgA, sifA, iroN, spiA, ipfC and pagC, respectively. The remaining virulence genes were absent in all of the isolates. Based on the combination of the presence and absence of virulence genes, eight profiles were detected among these isolates, the most common genetic profile was V5 (each 32.1%). Based on this genetic profile at cut-off point 96.0%, both ERIC and BOX primers allowed for discrimination into 4 and 6 clusters or clones of 16 S. Typhimurium isolates, respectively. Results of PCR typing methods showed that, three strains clustered together using both ERIC-PCR and BOX-PCR typing methods and they had the same virulotype (V1), while other four strains also clustered together by both typing methods and had the same virulotype (V8). Contamination of food with Salmonellae especially with S. Typhimurium was high and indicated a bad microbiological quality of food. This emphasizes the need for rigorous public health and food safety methods to lower the human health hazard and risk associated with Salmonellae infection

Light cycling as a key to understanding the outdoor behaviour of perovskite solar cells

Forecasting the real world stability of perovskite solar cells PSCs using indoor accelerated tests is a significant challenge on the way to commercialising this highly anticipated PV technology. The lack of outdoor data and considerable magnitude of meta stability effects or reversible changes in PSCs performance over the day night cycle makes it particularly challenging to correlate results of the commonly utilised light soaking ageing test with outdoor experiments. Here we show the variety of short term and long term ageing behaviours by testing PSCs of various architectures under constant and intermitted light indoors and exposing them to natural conditions outdoors. We demonstrate that it is impossible to predict the results of a light cycling test from a continuous light test without prior knowledge of the ageing patterns for a particular device architecture. Cycling the light does not necessarily lead to an increased lifetime as expected due to dark time recovery. Instead, it sometimes reveals a different degradation behaviour resulting in a drastic lifetime reduction. The presence of various degradation patterns for different PSCs implies that an accelerated ageing with constant light experiment is no worst case scenario and thus cannot replace the light cycling test nor can it reproduce the real world scenarios. Furthermore, we show unique sets of weeks to years long outdoor series on different PSCs highlighting the monumental importance of accounting for the meta stability effects when analysing PSC outdoor data as opposed to simply following evaluation routines developed for silicon based devices. In particular, meta stability complicates the decoupling of the effects of environmental conditions from the cell s ageing behaviour and can result in large artefacts. A varying degree of saturation of reversible processes also results in unusual strong seasonality documented for PSCs, with summer representing favourable conditions for some PSCs energy generation compared to winter, despite higher temperatures. For the first time, the decisive impact of meta stable processes on the outdoor performance and stability of perovskite solar cells is demonstrated, with data from over two years in the field, which is the longest outdoor exposure of PSCs reported so far to the best of our knowledge. The correlation between the outdoor results and those from the light cycled experiments is eviden

Inequalities in higher education in low‐ and middle‐income countries:A scoping review of the literature

Motivation:  Higher  education  is  regarded  as  a  key  instrument  to  enhance  socioeconomic  mobility  andreduce inequalities. Recent literature reviews have examined inequalities in the higher education systemsof  high-income  countries,  but  less  is  known  about  the  situation  in  low-  and  middle-income  countries,where higher education is expanding fast.Purpose:  The  article  reviews  the  academic  literature  on  higher  education  in  low-  and  middle-incomecountries using a research framework inspired by social justice and capability approaches. It considers the financial,  socio-cultural,  human,  and  political  resource  domains  on  which  people  draw,  and  how  they relate to access, participation, and outcomes in higher education.Methods: A literature search for studies explicitly discussing in-country  inequalities  in  higher  education revealed  22  publications. Substantial  knowledge  gaps remain,  especially  regarding  the  political  (and decision-making)  side  of  inequalities;  the  ideologies  and  philosophies  underpinning  higher  education systems; and the linkages between resource domains, both micro and macro.Findings:  The  review  highlights  key  elements  for  policy-makers  and  researchers:  (1)  the  financial  lens alone  is  insufficient  to  understand  and  tackle  inequalities,  since  these  are  also  shaped  by  human  and other non-financial factors; (2) socio-cultural constructs are central in explaining unequal outcomes; and (3) inequalities develop throughout one’s life and need to be considered during, but also before and afterhigher education.  The scope  of  inequalities  is  wide, and  the literature  offers a  few ideas  for short-term fixes such as part-time and online education.Policy implications: Inclusive policy frameworks for higher education should include explicit goals related to (in)equality,  which  are  best  measured in  terms  of  the  extent  to  which  certain  actions  or  choices are feasible for all. Policies in these frameworks, we argue, should go beyond providing financial support, and also address socio-cultural and human resource constraints and challenges in retention, performance, and labour market outcomes. Finally, they should consider relevant contextual determinants of inequalities.</p

Effects of osteopontin inhibition on radiosensitivity of MDA-MB-231 breast cancer cells

<p>Abstract</p> <p>Background</p> <p>Osteopontin (OPN) is a secreted glycophosphoprotein that is overexpressed in various tumors, and high levels of OPN have been associated with poor prognosis of cancer patients. In patients with head and neck cancer, high OPN plasma levels have been associated with poor prognosis following radiotherapy. Since little is known about the relationship between OPN expression and radiosensitivity, we investigated the cellular and radiation induced effects of OPN siRNA in human MDA-MB-231 breast cancer cells.</p> <p>Methods</p> <p>MDA-MB-231 cells were transfected with OPN-specific siRNAs and irradiated after 24 h. To verify the OPN knockdown, we measured the OPN mRNA and protein levels using qRT-PCR and Western blot analysis. Furthermore, the functional effects of OPN siRNAs were studied by assays to assess clonogenic survival, migration and induction of apoptosis.</p> <p>Results</p> <p>Treatment of MDA-MB-231 cells with OPN siRNAs resulted in an 80% decrease in the OPN mRNA level and in a decrease in extracellular OPN protein level. Transfection reduced clonogenic survival to 42% (p = 0.008), decreased the migration rate to 60% (p = 0.15) and increased apoptosis from 0.3% to 1.7% (p = 0.04). Combination of OPN siRNA and irradiation at 2 Gy resulted in a further reduction of clonogenic survival to 27% (p < 0.001), decreased the migration rate to 40% (p = 0.03) and increased apoptosis to 4% (p < 0.005). Furthermore, OPN knockdown caused a weak radiosensitization with an enhancement factor of 1.5 at 6 Gy (p = 0.09) and a dose modifying factor (DMF₁₀) of 1.1.</p> <p>Conclusion</p> <p>Our results suggest that an OPN knockdown improves radiobiological effects in MDA-MB-231 cells. Therefore, OPN seems to be an attractive target to improve the effectiveness of radiotherapy.</p

Distinct cytokine profiles of circulating mononuclear cells stimulated with Staphylococcus aureus enterotoxin A in vitro during early and late episodes of chronic osteomyelitis

We investigated the cytokine profile of peripheral mononuclear cells from chronic osteomyelitis (OST) patients following in vitro stimulation with staphylococcal enterotoxin A (SEA). We demonstrate that stimulation with SEA induced prominent lymphocyte proliferation and high levels of tumour necrosis factor (TNF)-α, interleukin (IL)-4 and IL-10 secretion in both OST and non-infected individuals (NI). Even though stimulation with SEA had no impact on IL-6 production in either patient group, the baseline level of IL-6 production by cells from OST patients was always significantly less than that produced by cells from NI. After classifying the osteomyelitic episodes based on the time after the last reactivation event as "early" (1-4 months) or "late" osteomyelitis (5-12 months), we found that increased levels of TNF-α and IL-4 in combination with decreased levels of IL-6 were observed in the early episodes. By contrast, increased levels of IL-10, IL-2 and IL-6 were hallmarks of late episodes. Our data demonstrate that early osteomyelitic episodes are accompanied by an increased frequency of "high producers" of TNF-α and IL-4, whereas late events are characterised by increased frequencies of "high producers" of IL-10, IL-6 and IL-2. These findings demonstrate the distinct cytokine profiles in chronic osteomyelitis, with a distinct regulation of IL-6 production during early and late episodes