Ethyl Alcohol Extract of Hizikia fusiforme Induces Caspase-dependent Apoptosis in Human Leukemia U937 Cells by Generation of Reactive Oxygen Species

Purpose: Hizikia fusiforme is renowned for the possession of anti-inflammatory and anti-oxidant properties. In this study, the role of the ethyl alcohol extract of H. fusiforme (EAHF) in the induction of apoptosis in human leukemia U937 cells was investigated.Methods: Protein expression was investigated by Western blot analysis. Cell viability and apoptosis were analyzed by an MTT assay and flow cytometric analysis. Caspase activity was analyzed using a caspase-specific kit.Results: EAHF suppressed the proliferation of U937 cells in a dose-dependent manner. This effect was closely related to the induction of apoptosis via the downregulation of IAP family members such as IAP-1, IAP-2 and XIAP, as well as Bcl-2 proteins. The results also showed that caspases play an essential role in EAHF-induced apoptosis by generating of reactive oxygen species (ROS). In addition, ROS scavenging by N-acetyl-L-cysteine (NAC) and glutathione (GSH) decreased EAHF-induced apoptosis via the suppression of caspase activity. Although EAHF induced the phosphorylation of mitogenactivated protein kinases (MAPKs), treatment with MAPK inhibitors did not affect EAHF-induced apoptosis.Conclusion: These results suggest that EAHF induces apoptosis in U937 cells via ROS-dependent caspase activation.Keywords: Hizikia fusiforme, Apoptosis, Caspase, Reactive oxygen specie

Ethics, space, and somatic sensibilities: comparing relationships between scientific researchers and their human and animal experimental subjects

Drawing on geographies of affect and nature-society relations, we propose a radical rethinking of how scientists, social scientists, and regulatory agencies conceptualise human and animal participants in scientif ic research. The scientific rationale for using animal bodies to simulate what could be done in human bodies emphasises shared somatic capacities that generate comparable responses to clinical interventions. At the same time, regulatory guidelines and care practices stress the differences between human and animal subjects. In this paper we consider the implications of this differentiation between human and animal bodies in ethical and welfare protocols and practices. We show how the bioethical debates around the use of human subjects tend to focus on issues of consent and language, while recent work in animal welfare reflects an increasing focus on the affectual dimensions of ethical practice. We argue that this attention to the more-than-representational dimensions of ethics and welfare might be equally important for human subjects. We assert that paying attention to these somatic sensibilities can offer insights into how experimental environments can both facilitate and restrict the development of more care-full and response-able relations between researchers and their experimental subjects. <br/

A Multi-Inventory Ensemble Analysis of the Effects of Atmospheric Rivers on Precipitation and Streamflow in the Namgang-Dam Basin in Korea

Atmospheric rivers (ARs) are an important concern in regional water management; however, little is known about the AR impacts on hydrology in East Asia (EA). This study analyzes the characteristics of storms, precipitation (P), streamflow (Q), and runoff coefficient (R) in the Namgang-dam basin in Korea related to ARs for 2000–2013, as well as the sensitivity of the analysis results to AR detection methods, using observed P, Q, and three different AR inventories. The basin experiences 37.3 storms annually, of which 54% are AR storms that provide over 60% of the annual P and Q. The AR (non-AR) storms are dominant in storm frequency and the storm-total P and Q for January–July (August–December) with peaks in July (August). The monthly AR frequency varies closely with the seasonal variations in the EA monsoon and the North Pacific storm track which modulate the number of extratropical cyclones. The AR storms produce most of the extreme events; they also generate larger storm-mean P and Q than the non-AR storms for all months. The seasonal variations in R are related to the total (AR- and non-AR storms combined) P through the seasonal soil water variations, making the AR effects on R unclear. Considering 95% confidence intervals, the AR storms are distinguished well from the non-AR storms in storm frequency and the storm-total and storm-mean P and Q. The sensitivity to AR inventories is not critical in quantifying the AR-storm characteristics and their impacts on hydrologic variables except for R

Magic Numbers of Silicon Clusters

A structural model for intermediate sized silicon clusters is proposed that is able to generate unique structures without any dangling bonds. This structural model consists of bulk-like core of five atoms surrounded by fullerene-like surface. Reconstruction of the ideal fullerene geometry results in the formation of crown atoms surrounded by $\pi$-bonded dimer pairs. This model yields unique structures for \Si{33}, \Si{39}, and \Si{45} clusters without any dangling bonds and hence explains why these clusters are least reactive towards chemisorption of ammonia, methanol, ethylene, and water. This model is also consistent with the experimental finding that silicon clusters undergo a transition from prolate to spherical shapes at \Si{27}. Finally, reagent specific chemisorption reactivities observed experimentally is explained based on the electronic structures of the reagents.Comment: 4 pages + 3 figures (postscript files after \end{document}

Control of Length and Spatial Functionality of Single-Wall Carbon Nanotube AFM Nanoprobes

Single-wall carbon nanotube (SWNT) nanofibrils were assembled onto conductive atomic force microscopy (AFM) probes with the help of dielectrophoresis (DEP). This process involved the application of a 10 V, 2 MHz, AC bias between a metal-coated AFM probe and a dilute suspension of SWNTs. This exerted a positive dielectrophoretic force onto the nanotubes that caused them to align while precipitating out onto the probe. The gradual removal of the AFM probe away from the SWNT suspension consolidated these nanotubes into nanofibrils with a high degree of alignment as demonstrated with polarization Raman experiments. By varying the pulling speed, immersion time, and concentration of the SWNT suspension, one can tailor the diameter and thus the stiffness of these probes. Precise length trimming of these nanofibrils was also performed by their gradual immersion and dissolution into a liquid that strongly interacted with nanotubes, (i.e., sodium dodecyl sulfate (SDS) solution). Vacuum annealing these nanoprobes at temperature up to 450 degree C further increased their stiffness and rendered them insoluble to SDS and all other aqueous media. Regrowth of a new SWNT nanofibril from the side or at the end of a previously grown SWNT nanofibril was also demonstrated by a repeated dielectrophoretic assembly at the desired immersion depth. These SWNT nanofibril-equipped AFM probes are electrically conductive and mechanically robust for use as high-aspect-ratio electrochemical nanoprobes

High School Students' Proficiency and Confidence Levels in Displaying Their Understanding of Basic Electrolysis Concepts

This study was conducted with 330 Form 4 (grade 10) students (aged 15 – 16 years) who were involved in a course of instruction on electrolysis concepts. The main purposes of this study were (1) to assess high school chemistry students’ understanding of 19 major principles of electrolysis using a recently developed 2-tier multiple-choice diagnostic instrument, the Electrolysis Diagnostic Instrument (EDI), and (2) to assess students’ confidence levels in displaying their knowledge and understanding of these electrolysis concepts. Analysis of students’ responses to the EDI showed that they displayed very limited understanding of the electrolytic processes involving molten compounds and aqueous solutions of compounds, with a mean score of 6.82 (out of a possible maximum of 17). Students were found to possess content knowledge about several electrolysis processes but did not provide suitable explanations for the changes that had occurred, with less than 45 % of students displaying scientifically acceptable understandings about electrolysis. In addition, students displayed limited confidence about making the correct selections for the items; yet, in 16 of the 17 items, the percentage of students who were confident that they had selected the correct answer to an item was higher than the actual percentage of students who correctly answered the corresponding item. The findings suggest several implications for classroom instruction on the electrolysis topic that need to be addressed in order to facilitate better understanding by students of electrolysis concepts

Conflict of Interest Policies at Canadian Universities: Clarity and Content

[À l'origine dans / Was originally part of : ESPUM - Dép. médecine sociale et préventive - Travaux et publications]Abstract Discussions of conflict of interest (COI) in the university have tended to focus on financial interests in the context of medical research; much less attention has been given to COI in general or to the policies that seek to manage COI. Are university COI policies accessible and understandable? To whom are these policies addressed (faculty, staff, students)? Is COI clearly defined in these policies and are procedures laid out for avoiding or remedying such situations? To begin tackling these important ethical and governance questions, our study examines the COI policies at the Group of Thirteen (G13) leading Canadian research universities. Using automated readability analysis tools and an ethical content analysis, we begin the task of comparing the strengths and weaknesses of these documents, paying particular attention to their clarity, readability, and utility in explaining and managing COI.This study was supported by a grant from the Institute of Genetics of the Canadian Institutes of Health Researc

Reversal of stress fibre formation by Nitric Oxide mediated RhoA inhibition leads to reduction in the height of preformed thrombi

Evidence has emerged to suggest that thrombi are dynamic structures with distinct areas of differing platelet activation and inhibition. We hypothesised that Nitric oxide (NO), a platelet inhibitor, can modulate the actin cytoskeleton reversing platelet spreading, and therefore reduce the capability of thrombi to withstand a high shear environment. Our data demonstrates that GSNO, DEANONOate, and a PKG-activating cGMP analogue reversed stress fibre formation and increased actin nodule formation in adherent platelets. This effect is sGC dependent and independent of ADP and thromboxanes. Stress fibre formation is a RhoA dependent process and NO induced RhoA inhibition, however, it did not phosphorylate RhoA at ser188 in spread platelets. Interestingly NO and PGI2 synergise to reverse stress fibre formation at physiologically relevant concentrations. Analysis of high shear conditions indicated that platelets activated on fibrinogen, induced stress fibre formation, which was reversed by GSNO treatment. Furthermore, preformed thrombi on collagen post perfused with GSNO had a 30% reduction in thrombus height in comparison to the control. This study demonstrates that NO can reverse key platelet functions after their initial activation and identifies a novel mechanism for controlling excessive thrombosis

A Global Perspective on Trends in Nature-Based Tourism

Falling attendance at United States and Japanese national parks has led to claims of a pervasive shift away from nature-based recreation. A global analysis, however, now suggests that while visit rates are declining slightly in some richer countries, elsewhere nature tourism is booming

Burden-driven feedback control of gene expression

Cells use feedback regulation to ensure robust growth despite fluctuating demands for resources and differing environmental conditions. However, the expression of foreign proteins from engineered constructs is an unnatural burden that cells are not adapted for. Here we combined RNA-seq with an in vivo assay to identify the major transcriptional changes that occur in Escherichia coli when inducible synthetic constructs are expressed. We observed that native promoters related to the heat-shock response activated expression rapidly in response to synthetic expression, regardless of the construct. Using these promoters, we built a dCas9-based feedback-regulation system that automatically adjusts the expression of a synthetic construct in response to burden. Cells equipped with this general-use controller maintained their capacity for native gene expression to ensure robust growth and thus outperformed unregulated cells in terms of protein yield in batch production. This engineered feedback is to our knowledge the first example of a universal, burden-based biomolecular control system and is modular, tunable and portable