Physiochemical Indicators of Single Walled Carbon Nanotube Toxicity

Numerous toxicity studies have been conducted to date both in vivo and in vitro on refined and raw Single Walled Carbon Nanotubes (SWCNT). Differences in SWCNT toxicity and biocompatibility have been observed between these studies, and whilst these discrepancies have been attributed to factors such as varying percentages of remnant catalytic particles, differences in dispersion methods etc. the mechanisms underlying these inconsistencies have not been investigated. This study used standard spectroscopic and cellular techniques to elucidate the origins of these inconsistencies and also to estimate the validity of toxicological data evaluated form standard cytotoxic endpoints. Spectroscopic studies were conducted in order to demonstrate and elucidate the interactions of HiPco SWCNT with cell culture medium and its components, prepared both with and without foetal bovine serum. Upon addition of raw SWCNT to the medium a noticeable colour change was observed. UV/Vis absorption spectroscopy revealed a dramatic reduction in the absorption attributable to the phenol red, a pH indicator within the medium, without an associated change in pH. Reductions were also observed in absorbance features attributed to various components of the medium indicating an interaction with the SWCNT. Fluorescence spectroscopy also revealed reductions in emission features associated with the components of the medium giving further support to an interaction. Concentration dependent studies of the fluorescent emission of the various components of the media were modelled to show a differing degree of interaction between the SWCNT and the various components. Finally, notable differences were observed between the behaviour with and without serum. Raman spectroscopy gave no indication of differences between raw SWCNT and those deposited from the medium suspension indicating that no debundling of the SWCNT occurred. The results and their implications for toxicity and in vitro studies are discussed. To investigate if these interactions could induce a secondary toxicity by medium depletion, further spectroscopic and cytotoxicity studies were performed. SWCNT media suspensions were created, centrifuged and filtered (0.2µm cellulose acetate filters) to remove the SWCNT. Spectroscopic analysis was carried out on the filtered samples to verify the removal of the SWCNT from the suspension but also to assess the degree of alteration of the medium due to the aforementioned interactions. Cytotoxicity studies were performed on human alveolar A549 cells with the depleted media. Two cytotoxic endpoints were employed to evaluate cytotoxicity, namely Alamar blue and neutral red. Concentration dependant exposures over different time periods revealed low acute cytotoxicity after 72 and 96 hour exposure to the filtered samples, verifying the proposed notion of a secondary toxicity due to medium depletion. Finally the direct cytotoxicity of single walled carbon nanotubes was evaluated in the A549 human alveolar carcinoma cell line. Cell viability was assessed using the following indicator dyes, Commassie Blue, Alamar Blue , Neutral Red, MTT and WST-1. Exposure of the A549 cells revealed the nanotubes to have low acute toxicity. However considerable variation was found depending on the dye employed. Spectroscopic analysis of the nanotubes’ interactions with the dyes revealed interactions in all cases, resulting in the reduction of the associated absorption/fluorescent emission which is used to evaluate particle toxicity. In addition to being sensitive, simple, safe and cost-effective the ideal test for in vitro cell cytotoxicity must also not interfere with the compound to be tested. The results therefore have comprehensively confirmed that the indicator dyes used in this study were not appropriate for the quantitative toxicity assessment of carbon nanotubes highlighting the pressing need for the development of alternative screening techniques

FPGA-based conformance testing and system prototyping of an MPEG-4 SA-DCT hardware accelerator

Two FPGA implementations of a shape adaptive discrete cosine transform (SA-DCT) accelerator are presented in this paper: one PCI-based and the other AMBA-based. The former is used for conformance testing with the MPEG-4 standard requirements. The latter is an alternative platform for system prototyping and has an architecture more representative of a mobile device. The proposed accelerator meets real time constraints on both platforms with a gate count of approximately 40k, and outperforms the optimised reference software implementation by 20/spl times/. It is estimated that the accelerator consumes 250mW on a Virtex-E FPGA and 79mW on a Virtex-II FPGA in the worst case scenario

High-dimensional quantum information processing with linear optics

Quantum information processing (QIP) is an interdisciplinary field concerned with the development of computers and information processing systems that utilize quantum mechanical properties of nature to carry out their function. QIP systems have become vastly more practical since the turn of the century. Today, QIP applications span imaging, cryptographic security, computation, and simulation (quantum systems that mimic other quantum systems). Many important strategies improve quantum versions of classical information system hardware, such as single photon detectors and quantum repeaters. Another more abstract strategy engineers high-dimensional quantum state spaces, so that each successful event carries more information than traditional two-level systems allow. Photonic states in particular bring the added advantages of weak environmental coupling and data transmission near the speed of light, allowing for simpler control and lower system design complexity. In this dissertation, numerous novel, scalable designs for practical high-dimensional linear-optical QIP systems are presented. First, a correlated photon imaging scheme using orbital angular momentum (OAM) states to detect rotational symmetries in objects using measurements, as well as building images out of those interactions is reported. Then, a statistical detection method using chains of OAM superpositions distributed according to the Fibonacci sequence is established and expanded upon. It is shown that the approach gives rise to schemes for sorting, detecting, and generating the recursively defined high-dimensional states on which some quantum cryptographic protocols depend. Finally, an ongoing study based on a generalization of the standard optical multiport for applications in quantum computation and simulation is reported upon. The architecture allows photons to reverse momentum inside the device. This in turn enables realistic implementation of controllable linear-optical scattering vertices for carrying out quantum walks on arbitrary graph structures, a powerful tool for any quantum computer. It is shown that the novel architecture provides new, efficient capabilities for the optical quantum simulation of Hamiltonians and topologically protected states. Further, these simulations use exponentially fewer resources than feedforward techniques, scale linearly to higher-dimensional systems, and use only linear optics, thus offering a concrete experimentally achievable implementation of graphical models of discrete-time quantum systems

Utopian Discourse in Contemporary Speculative Fiction

I argue in this dissertation that utopianism is a vibrant form of cultural production in the post-Cold War period, despite the paucity of recent texts depicting €œgood€ societies. Most literary historical accounts of the genre place the decline of the utopian narrative in the early twentieth century, with a brief resurgence in the 1960s and 1970s. Contemporary culture has since become inundated with dystopian and post-apocalyptic visions of the future. If we take this generic distribution at face-value, it seems symptomatic of the utopian idea\u27s retreat from cultural production since the 1980s. Influential critics have resisted this narrative by demonstrating that dystopian narratives can have utopian functions, but these arguments generally retain an investment in the traditional genre categories of utopia, anti-utopia, and dystopia that, I argue, are decreasingly useful in understanding the politics of contemporary speculative fiction. to navigate the political and generic complexity of contemporary speculative fiction, it is useful to conceptualize literary utopianism in discursive, rather than generic, terms. Utopian discourse, I argue, is a set of thematic and conceptual concerns, procedures of representation, and patterns of formal organization traceable through a wide range of speculative fiction texts that are invested in the politics of radical social betterment. This understanding of literary utopianism allows us to trace it through recent works of dystopian and post-apocalyptic fiction, science fiction, and fantasy that otherwise may be illegible as utopian texts. Doing so reveals that hope is a major structure of feeling in speculative fiction today

Liposomal encapsulation of silver nanoparticles (AgNP) improved nanoparticle uptake and induced redox imbalance to activate caspase-dependent apoptosis

Macrophages play a crucial role in several diseases’ development and progression, such as in cancer and arthritis through ROS generation and infammation. This makes macrophages a therapeutic target in these diseases. While silver nanoparticles (AgNP) have been widely used as an antibacterial and investigated as anticancer, its potential against macrophages may be limited due to its inherent oxidative mechanism. Here we encapsulated AgNP in a dipalmitoyl-phosphatidyl choline (DPPC) liposome (forming Lipo-AgNP) to suppress AgNP-induced ROS and enhance its cytotoxicity against THP1-diferentiated macrophages (TDM). Our fndings showed that while Lipo-AgNP had signifcantly more of a cytotoxic efect on TDMs (p\u3c0.01), it also signifcantly suppressed AgNP induced ROS generation and unexpectedly suppressed reduced glutathione (GSH) levels (p\u3c0.05) resulting in a redox imbalance in comparison to the unexposed control TDMs. Lipo-AgNP was also found to cause an increase DNA damage through H2AX histone phosphorylation and inhibition of Bcl-2 protein expression. This increased the Bax/Bcl2 ratio causing possible release of cytochrome C and subsequent caspase 3/7-dependent apoptosis. It was found that the diference between the mechanism of AgNP and Lipo-AgNP cytotoxicity may have been through the signifcantly increased Lipo-AgNP uptake by the TDMs as early as 30 min post-exposure (p\u3c0.05), changing the nanoparticle pharmacokinetic. In conclusion, the improved uptake of AgNP within the liposome caused ROS-independent caspase activation induced by Lipo-AgNP and this was facilitated by increased DNA damage, the induced redox imbalance and an increased Bax/Bcl-2 ratio

Introduction to Families and the Courts: Special Issue of \u3ci\u3eBehavioral Sciences & the Law\u3c/i\u3e

This special issue of Behavioral Sciences & the Law examines some of the many issues related to “Families and the courts.” As Judge Ted Rubin (this issue) observes, “Not everything or everybody ends up in a family court—or any other court—when there is a family problem. But much does and many do.” The issue deals with some of the family matters that do—or should—implicate the legal system (ranging from the attempts of gay men and lesbians to obtain legal recognition of their parental status vis-a-vis their children to the potential role of law in protecting children from emotional maltreatment by their parents). It also deals with issues regarding the nature, structure, definition, and jurisdiction of family courts; the practice of other courts that handle family matters (such as domestic violence), as well as some of the mental health professionals who aid the courts in their decision making. Scientific issues, practical issues, ethical issues, and political issues are covered. The six articles comprising the special issue span a vast territory

Evaluation of Silver Nanoparticle Encapsulation in DPPC-Based Liposome By Different Methods For Enhanced Cytotoxicity

Here we carried out a comparative study on two cost and time effective methods of encapsulating silver nanoparticles (AgNP) in dipalmitoyl-phosphatidyl choline (DPPC)/cholesterol-based liposome to enhance nanoparticle cytotoxicity, and evaluated the effect of this on a blood cell line (THP1 monocytes) often involved in uptake of nanoparticles during human exposure. DLS and Zeta potential analyses over a 6-months period showed the extruded Lipo-AgNP (Ex-Lipo-AgNP) exhibited more stable characteristics when compared with the probe-sonicated Lipo-AgNP (PB-Lipo-AgNP). SEM microscopy indicated agglomeration of the PB-Lipo-AgNP which was not observed in Ex-Lipo-AgNP. Ex-Lipo-AgNP also exhibited higher temperature-dependent stability with 35.3% reduction in size from 20 °C to 37 °C while PB-Lipo-AgNP was less stable exhibiting 55% size reduction over same temperature range and 6 h period. Load release study over 24 h showed controlled release from Ex-Lipo-AgNP while the PB-Lipo-AgNP exhibited burst release at pH 4 and 6.5. Interestingly, it was found that Ex-Lipo-AgNP induced significantly higher cytotoxicity on THP1 cell line after 24 h exposure compared with control unexposed cells, uncoated AgNP and PB-Lipo-AgNP exposed cells at the same concentration. Thus, we report here that liposomal encapsulation of AgNP by extrusion produces a stable nanocapsule with enhanced cytotoxicity, thus preventing overreliance on high AgNP concentration to achieve desired toxicity for in vitro and possible in vivo applications

Surface Modification of Silver Nanoparticle (AgNP) by Liposomal Encapsulation Mitigates AgNP-Induced Inflammation

Silver nanoparticles (AgNP) are widely used in a variety of consumable products as antibacterial to prevent or treat infection. Unfortunately, evidence exits that AgNP induces inflammation which can worsen with repeated human exposure. However, there is little or no research on how to mitigate these adverse effects due to AgNP induced-toxicity. Here, we investigated if surface modification of AgNP by liposomal encapsulation suppresses AgNP-mediated inflammatory responses in THP1 monocytes and THP1 differentiated macrophages (TDM). AgNP was encapsulated in a dipalmitoyl phosphatidyl choline- (DPPC)/cholesterol-based liposome by extrusion through a 100-nm polycarbonate membrane to form Lipo-AgNP. It was found as expected that AgNP induced significant release of IL-1β, IL-6, IL-8 and TNF-α in THP1 monocytes more than the basal level. Interestingly, release of these cytokines was suppressed by Lipo-AgNP. In TDMs, AgNP and Lipo-AgNP induced IL-8 release (p \u3c .0001), but Lipo-AgNP maintained IL-8 release at levels significantly lower than that of AgNP (p \u3c .01). However, both AgNP and Lipo-AgNP suppressed IL-1β and TNF-α release in LPS-stimulated THP1 monocytes and LPS-stimulated or unstimulated TDM respectively. We finally showed that Lipo-AgNP inhibits STAT-3 and this may be responsible for regulating the uncontrolled inflammation induced by AgNP likely mediated STAT-3 protein expression in LPS stimulated THP1 monocytes and TDMs, both LPS-stimulated and unstimulated. This data showed that Lipo-AgNP suppressed AgNP induced inflammation, making Lipo-AgNP particularly useful in treatment of bacteria induced inflammatory diseases and inflammatory cancers

Literature review: handpump functionality monitoring

This section provides a review of literature on handpump functionality monitoring. It seeks to highlight some of the functionality measurements used in the literature and describe the challenges that emerge from inconsistencies in the way the results of functionality studies are presented by authors