Cold Media Research Articles

Research on McLuhan's Media Theory

McLuhan is a master of media theory in the 20th century, who put forward influential media theories such as "Global Village", "The medium is the message", "The medium is an extension of the human being. He put forward influential media theories such as "Global Village", "Media is Information", "Media is an Extension of Human", and so on. McLuhan's profound insights and interdisciplinary thinking have had a profound impact on contemporary communication and art theories, and have helped to understand the interaction between the media and human beings in modern society. This paper examines McLuhan's media theory and consists of three parts: an introduction, two main chapters and a conclusion. The introduction part mainly explains the origin of the selected topic, and clarifies the innovation of this paper's research as well as the research methodology. The first chapter of the main text part discusses the relationship between media and communication, and the division of hot and cold media in turn. The second chapter discusses the dialectical relationship between media and contemporary art and technology from the perspectives of epistemology of media technology and media aesthetics, which is of great practical significance for us to correctly understand the relationship between media technology and human beings and society. The conclusion part summarizes the inevitability of McLuhan's media theory ideas, and further composes and elaborates that McLuhan's media theory is somewhat innovative.

Research on McLuhan's Media Theory

McLuhan is a master of media theory in the 20th century, who put forward influential media theories such as "Global Village", "The medium is the message", "The medium is an extension of the human being. He put forward influential media theories such as "Global Village", "Media is Information", "Media is an Extension of Human", and so on. McLuhan's profound insights and interdisciplinary thinking have had a profound impact on contemporary communication and art theories, and have helped to understand the interaction between the media and human beings in modern society. This paper examines McLuhan's media theory and consists of three parts: an introduction, two main chapters and a conclusion. The introduction part mainly explains the origin of the selected topic, and clarifies the innovation of this paper's research as well as the research methodology. The first chapter of the main text part discusses the relationship between media and communication, and the division of hot and cold media in turn. The second chapter discusses the dialectical relationship between media and contemporary art and technology from the perspectives of epistemology of media technology and media aesthetics, which is of great practical significance for us to correctly understand the relationship between media technology and human beings and society. The conclusion part summarizes the inevitability of McLuhan's media theory ideas, and further composes and elaborates that McLuhan's media theory is somewhat innovative.

Comprehensive laboratory constraints on thermal desorption of interstellar ice analogues

Gas accretion and sublimation in various astrophysical conditions are crucial aspects of our understanding of the chemical evolution of the interstellar medium. To explain grain growth and destruction in warm media, ice mantle formation and sublimation in cold media, and gas line emission spectroscopy, astrochemical models must mimic the gas--solid abundance ratio. Ice-sublimation mechanisms determine the position of snow lines and the nature of gas emitted by and locked inside planetary bodies in star-forming regions. To interpret observations from the interplanetary and extragalactic interstellar mediums, gas phase abundances must be modelled correctly. We provide a collection of thermal desorption data for interstellar ice analogues, aiming to put constraints on the trapping efficiency of water ice, as well as data that can be used to evaluate astrochemical models. We conduct experiments on compact, amorphous H$_2$O films, involving pure ices as well as binary and ternary mixtures. By manipulating parameters in a controlled way, we generate a set of benchmarks to evaluate both the kinetics and thermodynamics in astrochemical models. We conducted temperature-programmed desorption experiments with increasing order of complexity of ice analogues of various chemical compositions and surface coverages using molecular beams in ultrahigh vacuum conditions (1 times 10$^ $ hPa) and low temperatures (10 K). We provide TPD curves of pure ices made of Ar, CO, CO$_2$, NH$_3$, CH$_3$OH, H$_2$O, and NH$_4^+$HCOO$^-$, their binary ice mixtures with compact amorphous H$_2$O, ternary mixtures of H$_2$O : CH$_3$OH : CO, and a water ice made in situ to investigate its trapping mechanisms. Each experiment includes the experimental parameters, ice desorption kinetics for pure species, and the desorption yield (gas--solid ratio) for ice mixtures. From the desorption yields, we find common trends in the trapping of molecules when their abundance is compared to water: compact amorphous water ices are capable of trapping up to 20<!PCT!> of volatiles (Ar, CO, and CO$_2$), sim 3<!PCT!> of CH$_3$OH, and sim 5<!PCT!> NH$_3$ in relation to the water content within the ice matrix; ammonium formate is not trapped in the water ice films, and compact amorphous water ice formed in situ has similar trapping capabilities to a compact amorphous water ice deposited using molecular beams. Deposited or formed in a very compact structure, amorphous water ice of less than 100 layers cannot trap a large fraction of other gases, including CO and CO$_2$. These desorption yields offer insights into the availability of species that can react and form interstellar complex organic molecules during the warm-up phase of ice mantles. Furthermore, in order to be reliable, gas-grain astrochemical models should be able to reproduce the desorption kinetics and desorption yield presented in our benchmark laboratory experiments.

"Hot Media" and "Cold Media" in Photo News—Comment on the Winning Works of News Photography and News Cartoon Category of Hainan News

"Hot Media" and "Cold Media" in Photo News—Comment on the Winning Works of News Photography and News Cartoon Category of Hainan News

Direct evidence for a radiation-induced synthesis of acetonitrile and isoacetonitrile from a 1 : 1 CH4HCN complex at cryogenic temperatures: is it a missing link between inorganic and prebiotic astrochemistry?

Nitriles are important constituents of extraterrestrial media. Nitriles are supposed to play a crucial role in prebiotic chemistry occurring in the interstellar medium. In this work, we have investigated the low-temperature radiation-induced transformations of a 1 : 1 CH4HCN complex as a plausible precursor of the simplest nitriles using the matrix isolation approach with FTIR spectroscopic detection. The parent complexes isolated in a noble gas (Ng) matrix were obtained by deposition of the CH4/HCN/Ng gaseous mixture and characterized by comparison of experimental complexation-induced shifts of the HCN fundamentals with the results of the ab initio calculations. It was found that the X-ray irradiation of low-temperature matrices containing the isolated 1 : 1 CH4HCN complex resulted in the formation of acetonitrile (CH3CN) and isoacetonitrile (CH3NC) and it appears to be the first experimental evidence for the formation of C2 nitriles (acetonitrile and isoacetonitrile) from such a "building block". Additionally, a 1 : 1 CH4HNC complex was tentatively assigned to the irradiated Ar and Kr matrices. It is demonstrated that the matrix has a strong effect on the CH3CN/CH3NC yield ratio, which dramatically increases in the row Ar < Kr < Xe. Also, the efficiency of the radiation-induced formation of the CH4HNC complex was shown to decrease from Ar to Kr. It is believed that the proposed pathway for acetonitrile formation may be a significant step in the radiation-induced evolution leading to complex organic molecules and biomolecules under astrochemical conditions. Furthermore, the obtained results provide a prominent example of the impact of very weak intermolecular interactions on the radiation-induced transformations in cold media.

The multiphase environment in the centre of Centaurus A

ABSTRACT We study the multiphase medium in the vicinity of the active galactic nucleus Centaurus A (Cen A). Combined high-resolution observations with the Atacama Large Millimeter/submillimeter Array (ALMA) and Chandra X-ray Observatory indicate that the hot X-ray emitting plasma coexists with the warm and cold media in Cen A. This complex environment is a source of CO lines with great impact for its diagnostics. We present the images from the two above-mentioned instruments covering the nuclear region (diameter of 10 arcsec, i.e. ∼180 pc), and we study the conditions for plasma thermal equilibrium and possible coexistence of cool clouds embedded within the hot X-ray emitting gas. Further, we demonstrate that the multiphase medium originates naturally by the thermal instability arising due to the interaction of the high-energy radiation field from the nucleus with the ambient gas and dust. We demonstrate that cold gas clouds can coexist in the mutual contact with hot plasma, but even colder dusty molecular clouds have to be distanced by several hundred pc from the hot region. Finally, we propose a 3D model of the appearance of the hot plasma and the CO line-emitting regions consistent with the Chandra image, and we derive the integrated emissivity in specific molecular lines observed by ALMA from this model. To reproduce the observed images and the CO line luminosity the dusty shell has to be ∼420 pc thick and located at ∼1000 pc from the centre.

Ecological media perspective on WhatsApp status features

The presence of the internet today makes it easy for users to carry out communication activities without limitation of distance and time. Even instant messaging such as WhatsApp, which has the primary function as a medium for communication, can be a mediator for self-existence and cannot be separated from its users to share daily activities through the WhatsApp Status feature. The purpose of this study was to analyze the Status feature on Instant Messaging WhatsApp as a mediator to show self-existence without distance and time limits based on media ecology theory. The method in this study is a qualitative method with purposive data collection techniques. Researchers also conducted interviews with seven informants who were students and workers. This study's results indicate that the presence of this feature affects various actions, perceptions, and communication experiences in society. Ecological media has the perspective that electronic media has radically changed society. In essence, society is very dependent on technology that uses media, and that the social order of a society is based on its ability to deal with these technologies. Media, in general, act directly to form and organize culture. Apart from that, ecological media also has assumptions about how technology affects society, include the distinction between hot and cold media.

Immersività distratta. La nuova economia dell'attenzione negli ambienti digitali

The essay focuses on the relationship between attention and immersivity in the experience of digital media. The text aims at showing that this experience can be correctly understood only by developing an historical analysis of the notion of “attention”, and by considering the relationship between attention economy and the technological milieu, in which the subject is located. Therefore, the essay starts with a brief analysis of the concept of “attention” and with some historical remarks about the immersive character of media (with particular reference to the Greek notion of enar-geia).By discussing Walter Benjamin’s theory of cinematic experi-ence and Marshall McLuhan’s distinction between hot and cold media, the essay identifies the disjunction of attention and im-mersive experience as the core element necessary to understand our relationship to digital media.

Intensifying the PC conversion in the raceway by means of coke oven gas

Among numerous measures to accelerate the PC conversion within the blast furnace (BF) raceway, local increase of oxygen concentration is the most common one. On the other hand, the presence of cold media (oxygen) in the vicinity of the coal stream might affect its ignition and combustion negatively. A minor amount of coke oven gas (COG) may increase the temperature and consequently accelerate the coal conversion. To examine this effect, laboratory trials under blast furnace simulating conditions were performed using the Multifunctional Injection Rig for Ironmaking (MIRI). The results of the simulation testified a higher conversion degree of coal while adding the COG. The temperature increase is measurable in the reaction chamber and the off-gas stream. Optical microscopy of the original PC particles and residues after reaction confirm the findings of the off-gas analysis and the increase in temperature during the experiments with addition of COG. The thermogravimetric analysis was applied to determine and to compare the behaviour of coal in different atmospheres including an atmosphere with COG. A stand at one tuyère at a modern BF was erected and tests were performed targeting the observation of the ignition behaviour of coal at different COG rates, using a camera image analysis system. Laboratory trials under blast furnace raceway simulating conditions showed, that even a small amount of COG significantly improves the PC conversion degree. A new technology of PC injection, including addition of small amount of COG to the PC transporting gas, aimed at neutralization of the oxygen local cooling effect, elaborated, justified and tested.

Information, Communication and Art

Abstract From Karl Marx to Martin Heidegger, the dialectical relationship between technology and art has become an ontological question of social reality. Marshall McLuhan’s theory of cool-hot media provides an analytical framework for the information age. “Cool-hot media” is McLuhan’s truly original concept. However, while McLuhan determined electronic media to embrace printing media which was regarded as a typical representative of hot media, he could not foresee that electronic media is properly speaking the latest representative of the split type of hot media. Through Gödel’s Incompleteness Theorems which underlies formalization and Embodied Cognition Theory, this article argues that there exists an ontological difference between computers and human existence and explores the position of art from the contemporary cool media perspective. This contribution is not only intended to be a philosophical critique of the philosophy of technology of the media age, but also a repositioning of contemporary art and its function from the media perspective. The technological division and abstraction represented in hot media becomes the basic premise for a holistic approach to computer science and artificial intelligence. Their rich information context leads to multiple interpretations of meaning instead of a one-dimensional definition; the everyday actions of cold media have become a type of life art in a broad sense, and manifest their social function as an art of the information age, i.e. to balance the cognitive narrative of hot media and to ensure that its communication does not suppress the audience’s individual creativity, so that they can maintain their subjectivity by tracing the source of information. Art facilitates active audience participation and so allows participants to overcome a one dimensional way of thinking and promotes imagination and creativity in liberal arts education. Following the rules of art, cold media obtains its greatest significance as the guardian of the free subjectivity of all humans, which is alien to modern technology. Cold media and hot media balance each other to create a new way of producing and living that not only discovers but also safeguards the world.

The Coldness of Forgetting: OOO in Philosophy, Archaeology, and History

Abstract This article begins by addressing a critique of my book Immaterialism by the archaeologists Þóra Pétursdóttirr and Bjørnar Olsen in their 2018 article “Theory Adrift.” As they see it, I restrict myself in Immaterialism to available historical documentation on the Dutch East India Company (VOC), and they wonder how my account might have changed if I had discussed more typical archaeological examples instead: wrecked and sunken ships, released ballast, deserted harbors, distributed goods, and derelict fortresses. In response, I argue that my account was not therefore non-archaeological, since ruins are the topic of archaeology only by accident: the real subject of the discipline is what Marshall McLuhan describes as “cold media,” in the sense that they are low in information. McLuhan’s distinction between hot and cold media is shown to be surprisingly analogous to Aristotle’s difference between continua and discrete substances, and some consequences are drawn from this analogy.

Doughnut strikes sandwich: the geometry of hot medium in accreting black hole X-ray binaries

We study the effects of the mutual interaction of hot plasma and cold medium in black hole binaries in their hard spectral state. We consider a number of different geometries. In contrast to previous theoretical studies, we use a modern energy-conserving code for reflection and reprocessing from cold media. We show that a static corona above an accretion disc extending to the innermost stable circular orbit produces spectra not compatible with those observed. They are either too soft or require a much higher disc ionization than that observed. This conclusion confirms a number of previous findings, but disproves a recent study claiming an agreement of that model with observations. We show that the cold disc has to be truncated in order to agree with the observed spectral hardness. However, a cold disc truncated at a large radius and replaced by a hot flow produces spectra which are too hard if the only source of seed photons for Comptonization is the accretion disc. Our favourable geometry is a truncated disc coexisting with a hot plasma either overlapping with the disc or containing some cold matter within it, also including seed photons arising from cyclo-synchrotron emission of hybrid electrons, i.e. containing both thermal and non-thermal parts.

Abstract 3692: Long-lived pancreatic ductal adenocarcinoma slice cultures enable precise study of the immune microenvironment

Abstract Introduction Pancreatic ductal adenocarcinoma (PDA) remains a deadly disease that is rarely cured. Given the recent successes with immunotherapy for other malignancies and the fact that PDA is heavily infiltrated by effector T cells, we postulate that accurate modeling of the PDA immune microenvironment would allow us to unveil mechanisms of immunosuppression that could be overcome for therapeutic benefit. Methods PDA tumors were collected from the operating room and transported in cold media to the laboratory, where 250μm slices were cut using a vibratome and placed on 0.4μm pore size membrane inserts pre-coated with collagen gel and culture. Proliferation was measured using MTT assay and weight-adjusted optical density. Slices were fixed in 4% PFA for imaging after live immunofluorescence (IF) staining or for subsequent immunohistochemistry (IHC) prior to imaging. For proteomic analysis, slices were digested with trypsin and analyzed by mass spectrometry. To assess for immune cell migration into the tumor slices, isolated autologous splenocytes were stained with CFSE and added to the slice culture and imaged using IF after 6 days. Results Using light microscopy, we confirmed that cultured slices maintain their baseline morphology, architecture and surface area over 9 days in culture. The MTT assay showed stable growth over the same period; IHC for Ki-67 and cleaved Caspase-3 corroborated a similar pattern of proliferation and apoptosis after 6 days culture when compared to day 1. T cells (CD3+, CD8+ and FOXP3+), macrophages (CD68+, CD163+, and HLA-DR+), and stromal myofibroblasts (αSMA+) were confirmed to be present through day 6 using IHC. Quantitative proteomic analysis of over 3000 proteins showed that only 2-3% of proteins showed significant changes of abundance greater than 2 fold after 6 days in culture. However, when slice were challenged with cytotoxic drugs (staurosporine and cyclohexamide), there was a time- and dose-dependent response in proliferation and apoptosis compared with controls. The demonstration of the live and dynamic microenvironment was performed first via live multicolor IF including PDA cells (EpCAM+), fibroblasts (fibronectin+) and immune cells (both CD11b+ and CD8+ cells) within the microenvironment. Furthermore, co-culture of CFSE-labeled splenocytes on top of slices for 6 days. Z-stacked live confocal imaging confirmed their migration from the surface into the slice microenvironment. Conclusion Our study demonstrates that the PDA slice culture maintains original tumor microenvironment, and overall proteomic production and dynamic function response in vitro. The slice culture model thus represents a novel platform to evaluate both pharmaceutical and cell-based immunotherapies for mechanisms of action and potential synergism, effects on specific cell types of the microenvironment, and tumor-specific immunogenic potential. Citation Format: Xiuyun Jiang, David Seo, Jae Chang, Eslam Nigjeh, Sheng Pan, Florencia Jalikis, Venu Pillarisetty. Long-lived pancreatic ductal adenocarcinoma slice cultures enable precise study of the immune microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3692. doi:10.1158/1538-7445.AM2017-3692

UV PHOTODESORPTION OF METHANOL IN PURE AND CO-RICH ICES: DESORPTION RATES OF THE INTACT MOLECULE AND OF THE PHOTOFRAGMENTS

ABSTRACT Wavelength-dependent photodesorption rates have been determined using synchrotron radiation for condensed pure and mixed methanol ice in the 7–14 eV range. The VUV photodesorption of intact methanol molecules from pure methanol ices is found to be of the order of 10−5 molecules/photon, that is two orders of magnitude below what is generally used in astrochemical models. This rate gets even lower (&lt;10−6 molecules/photon) when the methanol is mixed with CO molecules in the ices. This is consistent with a picture in which photodissociation and recombination processes are at the origin of intact methanol desorption from pure CH3OH ices. Such low rates are explained by the fact that the overall photodesorption process is dominated by the desorption of the photofragments CO, CH3, OH, H2CO, and CH3O/CH2OH, whose photodesorption rates are given in this study. Our results suggest that the role of the photodesorption as a mechanism to explain the observed gas phase abundances of methanol in cold media is probably overestimated. Nevertheless, the photodesorption of radicals from methanol-rich ices may stand at the origin of the gas phase presence of radicals such as CH3O, therefore, opening new gas phase chemical routes for the formation of complex molecules.

Conditions for thermal instability in the Galactic Centre mini-spiral region

We explore the conditions for the thermal instability to operate in the mini-spiral region of the Galactic centre (Sgr A*), where both the hot and cold media are known to coexist. The photoionisation Cloudy calculations are performed for different physical states of plasma. We neglect the dynamics of the material and concentrate on the study of the parameter ranges where the thermal instability may operate, taking into account the past history of Sgr A* bolometric luminosity. We show that the thermal instability does not operate at the present very low level of the Sgr A* activity. However, Sgr A* was much more luminous in the past. For the highest luminosity states the two-phase medium can be created up to 1.4 pc from the centre. The presence of dust grains tends to suppress the instability, but the dust is destroyed in the presence of strong radiation field and hot plasma. The clumpiness is thus induced in the high activity period, and the cooling/heating timescales are long enough to preserve later the past multi-phase structure. The instability enhances the clumpiness of the mini-spiral medium and creates a possibility of episodes of enhanced accretion of cold clumps towards Sgr A*. The mechanism determines the range of masses and sizes of clouds; under the conditions of Sgr A*, the likely values come out $1$ - $10^2M_{\oplus}$ for the cloud typical mass.

Effective Computation of Solutions for Nonlinear Heat Transfer Problems in Fins

Fins are essentially used in diverse engineering applications to increase the heat transfer between the hot and cold media. In this paper, a technique for computing the analytic approximate solution of the nonlinear differential equations resulting from heat transfer problems, in particular through fins, is developed. The simplicity of the approach presented here is due to its base functions, which makes this method straightforward to apply and formulate without any need for discretization. Analysis of the error and comparisons with the other methods are presented. A few physically interesting fin problems of heat transfer are treated to illustrate that the proposed algorithm generates highly accurate solutions.

Effects of Water or Brine Immersion Thawing Combined with Ultrasound on Quality Attributes of Frozen Pork Loin.

This study explored the effects of water or brine (2% NaCl, w/v) immersion thawing combined with ultrasound treatment (40 kHz, 150 W) on the quality characteristics of pork. Ultrasound treatment of pork was conducted in two cold media (at 4℃), water and 2% (w/v) brine, respectively. Because the ultrasound treatment caused temperature increase in the media from 4℃ to 16℃, the qualities of pork thawed by ultrasound were compared with those thawed by immersion either in water or brine where the temperature was being maintained at either 4℃ (low temperature control) or 17℃ (high temperature control). The ultrasound treatment resulted in rapid thawing of pork where the thawing rate was similar to those thawed in the 17℃ media. For quality characteristics, ultrasound-treated pork in brine had an advantage of less cooking losses when comparing to the control. In particular, ultrasound treatment in brine exhibited the lowest shear force (or highest tenderness) among the freezing/thawing treatments. Although the ultrasound processing in brine caused discoloration of the pork, this thawing technique had potential to be applied as a commercial thawing technology for frozen foods.

Metabolism of Radiolabeled Methionine in Hepatocellular Carcinoma

Radiolabeled methionine (Met) promises to be useful in the positron emission tomography (PET) imaging of hepatocellular carcinoma (HCC). However, its metabolic routes in HCC have not yet been fully understood. In this study, the metabolic pathway(s) of radiolabeled Met in HCC were investigated. To simulate the rapid blood clearance of radiolabeled Met, pulse-chase experiments were conducted. L-[methyl-(3)H]-Met or L-[1-(14)C]-Met was pulsed over control or cycloheximide-treated WCH17 cells and rat hepatocytes for 5min and chased with cold media. The water-soluble, lipid-soluble, DNA, RNA, and protein phases were subsequently extracted and measured from the acid-precipitable and acid-soluble fractions of whole cells. The radioactive metabolites Met, S-adenosylmethionine (SAM), S-adenosylhomocysteine, Met sulfoxide, and Met sulfone were further separated by radio thin layer chromatography. (1) The uptake of L-[methyl-(3)H]-Met in both cell types was higher than that of L-[1-(14)C]-Met. In rat hepatocytes, the uptake of L-[methyl-(3)H]-Met was significantly higher than that of L-[1-(14)C]-Met, which may contribute to its physiologic accumulation in surrounding hepatic tissues seen in PET imaging of HCC using L-[methyl-(11)C]-Met. Compared to rat hepatocytes, WCH17 cells had significantly higher uptake of both radiotracers. (2) For L-[methyl-(3)H]-Met, the major intracellular uptake was found mostly in the protein phase and, to a lesser degree, in the phosphatidylethanolamine (PE) methylation pathway, which is fairly stabilized within the 55-min chase period (the main metabolites were SAM, Met, Met sulfoxide, and Met sulfone). In contrast, the uptake of Met in rat hepatocytes mainly points to phosphatidylcholine (PC) synthesis through the PE methylation pathway (the main metabolite was PC). (3) Both cell types incorporated L-[1-(14)C]-Met predominantly into protein synthesis. (4) Finally, when the protein synthesis pathway was inhibited, the incorporation of SAM derived from L-[methyl-(3)H]-Met to lipid class (PC was the main metabolite) occurred at a reduced rate in WCH17 cells, suggesting that the route may be impaired in HCC. This study demonstrated that different metabolic pathways of radiolabeled Met exist between HCC and surrounding hepatic tissue and contribute to the patterns of increased uptake of radiolabeled Met in HCC.

Formation of stationary light in a medium of nonstationary atoms

We systematically study stationary light pulses formed in cold atomic media based on the effect of electromagnetically induced transparency (EIT) with counterpropagating laser fields. In contrast to hot media, the formation of stationary light in cold media is not straightforward. Detrimental coherences of high spatial frequencies can be excited which are naturally suppressed in hot media. We demonstrate numerically that these excitations prevent the formation of stationary light in cold media. We further present numerical and experimental results which show that these excitations can be dynamically suppressed in a medium of nonstationary atoms by reducing the width of the EIT transparency window below the typical Doppler shifts present in the medium. This provides an increased interaction time of the light pulses with the medium and enhances the efficiency of nonlinear optical interactions.

Analyze p53 degradation by 35S p53 Pulse Chase Analysis

p53, is known as the guardian of the genome and as such requires exquisite regulation not only of its abundance but also its activity. The abundance of p53 can be modulated at the level of transcription, translation, and also via its degradation.This protocol involves 35S metabolic labelling of newly synthesized proteins followed by a period of chase with &quot;cold&quot; media. Samples are harvested and p53 immunopreciptiated, separated by SDS PAGE and the levels of 35S labelled p53 determined. By comparing the level of 35S p53 at 0 h to those &quot;chased&quot; with cold media (e.g. 60 min) provides an indication of the rate of p53 turnover.