Reversible Signal Research Articles

Objective evaluation of sound quality for attacks on robust audio watermarking

Various attacks on robust audio watermarking have been proposed. Reversible signal processing attacks, such as sampling frequency conversion, degrade sound quality of the distributed watermarked audio (stego audio) and disturb extraction of hidden data so that copyright detection systems using automated crawling are invalidated. Reversible signal processing of the attack can recover sound quality of the degraded audio data. In order to prove validity and security of audio watermarking system, analysis of the presumed attacks or reversible signal processing on stego audio, is required. However, these attacks on audio signal also degrade sound quality of commercial music where such pieces of music are considered to be not suitable for appreciation. Therefore, degradation of sound quality induced by various attacks should be taken into account to decide if the intensity of the attacks are realistic. In this study, objective audio quality measurement (PEAQ) was applied to the audio signals including typical perceptual coding, MP3, tandem MP3, MPEG4AAC, and reversible signal processing of sampling frequency conversion, noise addition, frequency shift, bandpass filtering, and echo addition. The results indicate requirements for robustness and criteria of the attacks on high quality and robust audio watermarking technology.

Synthesis of aromatic poly(pyridinium salt)s and their electrochromic properties

Synthesis of a series of new conjugated electrochromic polymeric pyridinium salts containing main-chain triphenylamine and their electrochromic properties were demonstrated. All polymers exhibit intense UV absorptions at 336–338 nm in DMF and 340–343 nm in thin film form and fluorescence centered at 410–438 nm in DMF and 460–461 nm in thin film form. The electrochromic properties of the films were investigated by electrochemical and spectroelectrochemical methods. Reversible redox signals with stable electrochromic characteristics were obtained via cyclic voltammetry. The electrochromic properties of the polymers remain highly stable after 50 cycles between 0 and 1.2 V.

Multiple antiplatelet therapy contributes to the reversible high signal spots on diffusion-weighted imaging in elective coiling of unruptured cerebral aneurysm

Our aim was to systematically investigate radiographic characteristics and outcome of diffusion-weighted imaging (DWI) changes in the elective coiling of unruptured cerebral aneurysm with analyzing the correlation of antiplatelet therapy (APT). In a total of 34 consecutive patients with unruptured cerebral aneurysms initially treated by coiling without stent assist, 26 (76.5%) had DWI changes with 91 high signal spots within 24-48 h after the procedure. We recorded DWI parameters (location, volume, mean, and minimum values of the apparent diffusion coefficient: expressed as ADCAVE and ADCMIN) for each lesion, and evaluated its radiographic outcome on conventional MRI at follow-up (interval, 58.4 ± 37.2 days) in the modes of APT. All patients with DWI high spots had no clinical symptoms. There was a strong correlation between ADCAVE and ADCMIN (r = 0.82, p < 0.0001). The mean ADCAVE and rADCAVE were 0.74 ± 0.14 × 10(-3) mm(2)/s and 87 ± 10 %. DWI high spots were small with a mean volume of 0.13 ± 0.12 cm(3), ranging from 0.04 to 0.86 cm(3). A negative correlation was observed between the volume and values of ADCAVE (r = -0.48, p < 0.0001). The DWI volume was significantly larger in single APT than in multiple (0.15 ± 0.14 versus 0.10 ± 0.07 cm(3), p = 0.0091). The permanent signal change was more observed in single APT than in multiple (24.5% versus 5.2%, p = 0.02). DWI high spots after elective coiling were small without significant decrease of ADC, and do not correspond to brain infarction. Periprocedural use of multiple antiplatelet agents is expected to reduce the volume of thromboembolism and permanent tissue damages.

Severe Posterior Reversible Encephalopathy in Pheochromocytoma: Importance of Susceptibility-Weighted MRI

Pheochromocytoma is a rare cause of hypertension in children. Hypertension is one of the common reasons of posterior reversible encephalopathy. Intracerebral hemorrhage is a serious and unexpected complication of hypertensive encephalopathy due to pheochromocytoma, and very rarely seen in the childhood. Intracerebral hemorrhages should be searched if there are hypertensive reversible signal changes on the brain. Susceptibility weighted imaging (SWI) is a more sensitive method than conventional MRI when demonstrating cerebral microhemorrhagic foci. This is the first report of SWI findings on intracerebral hemorrhages in basal ganglia, brain stem and periventricular white matter due to hypertensive encephalopathy in a child with pheochromocytoma.

Insights into the electrochemical behaviour of composite materials: Monovacant polyoxometalates @ porous metal-organic framework

The first electrochemical investigation of composites materials based in polyoxometalates (POMs) encapsulated in the porous Metal-Organic Framework (MOF) MIL-101 is reported. The electrochemical behaviour of the porous MIL-101 and composite materials based in two monovacant Keggin-type POMs {K7[PW11O39]·10H2O (PW11) and K8[SiW11O39]·13H2O (SiW11)} encapsulated in MIL-101 (respectively, PW11@MIL-101 and SiW11@MIL-101) were studied by cyclic voltammetry. Initially, to investigate the influence of the support MIL-101 in the electrochemical behaviour of the two monovacant POMs, the compounds were individually immobilized on the surface of a pyrolytic graphite (PG) electrode. A reversible surface-controlled redox signal attributed to the chromium metal centres (Cr3+/Cr2+) was identified in MIL-101, and this represents the first electrochemical study of this MOF material. The monovacant compounds PW11 and SiW11 also revealed surface-controlled processes corresponding to WVI↔WV reductions. PW11 showed two reversible signals (involving one or two electrons), whereas SiW11 showed a quasi-reversible one-electron and a reversible two-electron process for the first and second W reductions, respectively. For the latter, an extra process was detected and attributed to the formation of β-isomer (β-SiW11). When the composites materials PW11@MIL-101 and SiW11@MIL-101 were immobilized on the surface of the electrode, the support MIL-101 maintained its characteristic electrochemistry and the redox potentials of the POMs were not significantly changed. However, when encapsulated inside the cages of the support material the POMs revealed a distinct electrochemical behaviour, given that their redox processes became diffusion-controlled, indicating that the POMs have some degree of mobility inside the support framework.

Electrochemical and chemical formation of a low-barrier proton transfer complex between the quinone dianion and hydroquinone

The electrochemistry of the 1,4-benzoquinone and hydroquinone in acetonitrile and dimethylsulfoxide was reviewed to explain the nature of a broad reversible signal that appears during the reduction of quinones with small amounts of proton donors and that cannot be explained in the framework of the classical mechanisms of quinone reduction. Cyclic voltammetry and NMR experiments as well as electronic structure calculations were performed to show that under specific conditions, the anion QH− disproportionates into a face-to-face dianionic quinhydrone associated by strong intermolecular hydrogen bonds. This complex explains the mentioned broad signal and the results presented show that it can be formed during the reduction of benzoquinone in the presence of stoichiometric amounts of weak proton donors such as acetic acid and hydroquinone, or by half-deprotonation of hydroquinone. An analysis of the energetic barriers of the hydroxyl protons involved in the complex is also presented in this work.

Reversible laminar signal intensity in deep cortical gray matter in T1-weighted images and FLAIR after mild acute hyperammonemic hepatic encephalopathy

Soporific acute hyperammonemic hepatic encephalopathy (aHE) can induce considerable changes in cerebral white and gray matter. This report describes a patient in the subacute phase of aHE grade I without disturbed consciousness and with reversible fine laminar cortical involvement on magnetic resonance imaging (MRI). The 59-year-old patient had esophageal varices bleeding due to primary biliary cirrhosis (ammonium blood level: 140 mmoL/L) and presented with sensory Jacksonian seizures, dysarthria, and increased drowsiness and fatigue. MRI revealed patchy hyperintense (T2-weighted, T2w) white-matter lesions and bilateral signal intensities in the striatum (T1w). During a rise of ammonium blood level to 220 mmoL/L, the patient had increased drowsiness, persistent dysarthria and mild temporary hemiparesis without loss of consciousness. Two weeks later, the patient was asymptomatic and blood ammonium level had reverted to normal value. MRI at that time revealed bihemispheric fine laminar subcortical hyperintensities on T2w and fluid-attenuated inversion recovery (FLAIR) imaging, and partially on T1w sequences, with no swelling or restricted diffusion; the hyperintensities were fully reversible a month later. Such a distinct cortical signal increase not only on T2w images, but also on T1w, in a patient after a mild form of aHE is a new MR finding.

Photochemical properties of photosystem 1 immobilized in a mesoporous semiconductor matrix

The pigment-protein complex of photosystem 1 (PS1) isolated from cyanobacterium Synechocystis sp. PCC 6803 has been adsorbed on a solid mesoporous film made from TiO2 nanoparticles. was on The TiO2 film supported on a glass substrate with a surface area of 1 cm2 adsorbs up to 0.045 nmol of PS1. PS1 molecules are distributed in the pores of the mesoporous support. Immobilization has an insignificant effect on the optical and photochemical properties of PS1. A reversible photoinduced EPR signal from the oxidized primary electron donor P700 of immobilized PS1 has been detected. It has been shown by photoelectrochemical methods that the photoexcitation of PS1 results in electron injection from PS1 to the conduction band of TiO2.

Covalent immobilization of a fluorescent pH-sensitive naphthalimide dye in sol–gel films

A pH indicator dye was covalently linked to inorganic–organic hybrid sol–gel layers via its carboxyl function by the formation of an amide bond. For this, the dye was activated by 2-succinimido-1,1,3,3-tetramethyluronium tetrafluoroborate and linked to N-(3-(trimethoxysilyl)propyl)-ethylendiamine. Different ratios of tetraethoxy-silane, diisobutyldimethoxysilane and 3-glycidoxypropyltrimethoxysilane were evaluated to tailor the performance of the sensing material. Fluorescence spectroscopy of the optimised sensor layers with a molar ratio of organically modified siloxane to tetraethoxysilane of 25.9 and of dye/amino groups of 1.16, showed a reversible fluorescence signal increase of 117 % upon protonation, and a pk a 6.5. The signal changes were caused by photoinduced electron transfer between the methylpiperazine moiety and the naphthalimide fluorophore, its efficiency being modulated by protonation of the methylpiperazine nitrogen. The influence of parameters such as synthesis, dip-coating process and heat-treatment on the performance of the sensor layers was investigated. Optimum signal changes were obtained when heating the sol–gel structure up to 170 °C.

Transparent Gold as a Platform for Adsorbed Protein Spectroelectrochemistry: Investigation of Cytochrome c and Azurin

The majority of protein spectroelectrochemical methods utilize a diffusing, chemical mediator to exchange electrons between the electrode and the protein. In such methods, electrochemical potential control is limited by mediator choice and its ability to interact with the protein of interest. We report an approach for unmediated, protein spectroelectrochemistry that overcomes this limitation by adsorbing protein directly to thiol self-assembled monolayer (SAM) modified, thin (10 nm), semitransparent gold. The viability of the method is demonstrated with two diverse and important redox proteins: cytochrome c and azurin. Fast, reversible electrochemical signals comparable to those previously reported for these proteins on ordinary disk gold electrodes were observed. Although the quantity of protein in a submonolayer adsorbed at an electrode is expected to be insufficient for detection of UV-vis absorption bands based on bulk extinction coefficients, excellent spectra were detected for each of the proteins in the adsorbed state. Furthermore, AFM imaging confirmed that only a single layer of protein was adsorbed to the electrode. We hypothesize that interaction of the relatively broad gold surface plasmon with the proteins' electronic transitions results in surface signal enhancement of the molecular transitions of between 8 and 112 times, allowing detection of the proteins at much lower than expected concentrations. Since many other proteins are known to interact with gold SAMs and the technical requirements for implementation of these experiments are simple, this approach is expected to be very generally applicable to exploring mechanisms of redox proteins and enzymes as well as development of sensors and other redox protein based applications.

Profound hypoglycemia presents with reversible symmetrical ADC signal changes isolated to eloquent cortex of the parietal lobe

MRI diffusion/ADC signal change with reversal, symmetrically isolated to the cortex of the precentral gyri in profound hypoglycemia has not been previously described. We present a case in which minimal cortical signal change without deep gray matter involvement and subsequent reversal occurred without significant clinical improvement. Correlation of the reversal of diffusion/ADC signal to findings by EEG evaluation has been described in animal studies and not in humans before.

Single Protein Molecule Detection with a Transfer-APTamer (Piston) Sliding in a Protein Pore

Aptamers are specific oligonucleotide molecules that bind to various biologically important target molecules. Nanopores are powerful tools for the identification and detection of single molecules, such as DNA, RNA and proteins. α-hemolysin nanopore is utilized to sense the single protein molecule with a transfer-aptamer (piston). The transfer-aptamer (piston) containing polyethylene glycol (PEG) has functions as identified which zone of the beta barrel of pore. Here we report the formation of reversible signature signals using protein engineering, and characterized change the pore conductance depend on special design of transfer-aptamer (piston). The transfer-aptamer was bound with thrombin, which can be trapped to the pore opening and distinguished signature current block compared the thrombin being released from the transfer-aptamer (piston). But, the signal of aptamer only contains DNA which is indistinguishable with or without thrombin. By containing specific tail of aptamer, presence of single protein molecule, we capture the reversible thrombin signature signal using protein pore. The transfer-aptamer (piston) can be used as detector of different ions for nanomachine, nanomaterials, and folding process.

Intermittent‐relapsing pyruvate dehydrogenase complex deficiency: a case with clinical, biochemical, and neuroradiological reversibility

Pyruvate dehydrogenase complex (PDHC) deficiency causes encephalomyopathies, of which there are four major categories: (1) neonatal encephalopathy with lactic acidosis; (2) an early infantile form, which (3) at times resembles Leigh syndrome; and (4) a later-onset form. Long-term clinical and radiological follow-up is still incompletely elucidated. We report a 12-year-old male with intermittent-relapsing PDHC deficiency who presented with three typical acute episodes of metabolic decompensation over 7 years. Neuroimaging showed reversible signal abnormalities in the basal ganglia, inferior olivary nuclei, periaqueductal grey matter, and dentate nuclei, with evidence of lactate on magnetic resonance spectroscopy. Molecular analysis of PDH1A revealed a novel hemizygous c.1045G>A mutation, predicting a p.A349T missense mutation. He was treated with thiamine supplementation and, while on this regimen, he experienced several intercurrent febrile episodes without neurological compromise. This case report stresses the importance of performing neuroimaging during acute clinical episodes because brain lesions in PDHC deficiency may be transient and reversible, and false-negative results may mislead the diagnosis and delay the treatment.

Polymer-based carbon-nanotube film with reversible signal tracking capabilities

This study presents a polymer-based carbon-nanotube (CNT) sensing polymer with reversible signal tracking capabilities. The sensing polymer was prepared by dispersing multi-walled CNTs (MWCNTs) and silver nanoparticles into the polydimethylsiloxane (PDMS) polymer matrix. Before curing the PDMS prepolymer, MWCNTs were aligned in the prepolymer, using the dielectrophoresis (DEP) technique. Under an external force, the polymer increased and retained resistivity, which could be recovered to its original value by repeating DEP. Similar resistivity behaviors induced by temperature elevation and DEP were also observed. This study also presents the measured performance and repeatability. The potential applications of the sensing polymer include reusable inertia switches, footstep tracking carpets, and temperature switches.

Rotavirus encephalitis and cerebellitis with reversible magnetic resonance signal changes

Pediatrics InternationalVolume 53, Issue 2 p. 252-255 Rotavirus encephalitis and cerebellitis with reversible magnetic resonance signal changes Toshihiko Mori, Corresponding Author Toshihiko Mori Department of Pediatrics, NTT East Sapporo HospitalToshihiko Mori, MD PhD, Department of Pediatrics, NTT East Sapporo Hospital, South-1, West-15, Chuo-ku, Sapporo 060-0061, Japan. Email: [email protected]Search for more papers by this authorMayuko Morii, Mayuko Morii Department of Pediatrics, NTT East Sapporo HospitalSearch for more papers by this authorYuki Kuroiwa, Yuki Kuroiwa Department of Pediatrics, NTT East Sapporo HospitalSearch for more papers by this authorTomoyuki Hotsubo, Tomoyuki Hotsubo Department of Pediatrics, NTT East Sapporo HospitalSearch for more papers by this authorShigeto Fuse, Shigeto Fuse Department of Pediatrics, NTT East Sapporo HospitalSearch for more papers by this authorHiroyuki Tsustumi, Hiroyuki Tsustumi Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, JapanSearch for more papers by this author Toshihiko Mori, Corresponding Author Toshihiko Mori Department of Pediatrics, NTT East Sapporo HospitalToshihiko Mori, MD PhD, Department of Pediatrics, NTT East Sapporo Hospital, South-1, West-15, Chuo-ku, Sapporo 060-0061, Japan. Email: [email protected]Search for more papers by this authorMayuko Morii, Mayuko Morii Department of Pediatrics, NTT East Sapporo HospitalSearch for more papers by this authorYuki Kuroiwa, Yuki Kuroiwa Department of Pediatrics, NTT East Sapporo HospitalSearch for more papers by this authorTomoyuki Hotsubo, Tomoyuki Hotsubo Department of Pediatrics, NTT East Sapporo HospitalSearch for more papers by this authorShigeto Fuse, Shigeto Fuse Department of Pediatrics, NTT East Sapporo HospitalSearch for more papers by this authorHiroyuki Tsustumi, Hiroyuki Tsustumi Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, JapanSearch for more papers by this author First published: 19 April 2011 https://doi.org/10.1111/j.1442-200X.2010.03221.xCitations: 16Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume53, Issue2April 2011Pages 252-255 RelatedInformation

Life imitates art

Treatment of Alzheimer disease (AD) by infusion of antibodies against the β-amyloid peptide (Aβ) is currently in clinical trials. The rationale behind this passive immunotherapeutic approach is to clear or neutralize the amyloid peptide's toxic forms. Although determining efficacy at slowing or preventing AD progression is the primary focus of these trials, issues of the safety of anti-AD immunotherapy have also arisen. Approximately 10% of clinical trial subjects receiving the humanized anti-Aβ antibody bapineuzumab1 developed a condition termed vasogenic edema (VE), consisting of reversible T2-hyperintense signal on MRI in the white matter, leptomeninges, and sulci, sometimes associated with clinical symptoms such as headache, changes in mental status, vomiting, and gait disturbance. VE occurred more commonly in subjects receiving higher doses of antibody and in carriers of the APOE ϵ4 allele. Although the pathogenesis of antibody-related VE remains undefined (with no neuropathologic findings yet reported), an intriguing possibility is that it results from an immune response directed toward cerebrovascular Aβ deposits (cerebral amyloid angiopathy [CAA]). There is evidence for this in the notable similarities between antibody-related VE and the syndrome of …

TiO2/LiCl-Based Nanostructured Thin Film for Humidity Sensor Applications

A simple and straightforward method of depositing nanostructured thin films, based on LiCl-doped TiO(2), on glass and LiNbO(3) sensor substrates is demonstrated. A spin-coating technique is employed to transfer a polymer-assisted precursor solution onto substrate surfaces, followed by annealing at 520°C to remove organic components and drive nanostructure formation. The sensor material obtained consists of coin-shaped nanoparticles several hundred nanometers in diameter and less than 50 nm thick. The average thickness of the film was estimated by atomic force microscopy (AFM) to be 140 nm. Humidity sensing properties of the nanostructured material and sensor response times were studied using conductometric and surface acoustic wave (SAW) sensor techniques, revealing reversible signals with good reproducibility and fast response times of about 0.75 s. The applicability of this nanostructured film for construction of rapid humidity sensors was demonstrated. Compared with known complex and expensive methods of synthesizing sophisticated nanostructures for sensor applications, such as physical vapor deposition (PVD) and chemical vapor deposition (CVD), this work presents a relatively simple and inexpensive technique to produce SAW humidity sensor devices with competitive performance characteristics.

New copper(ii)-centered complexes with organometallic donor–acceptor substituted unsymmetrical Schiff base ligands

The synthesis and full characterization using various spectroscopic techniques and single-crystal X-ray diffraction analysis of a family of three robust copper(II)-centered complexes with organometallic donor–acceptor substituted unsymmetrical Schiff base ligands, namely, the binuclear derivatives Cu[Fc–C(O)CHC(CH3)N–X–NCH-(2-O,5-Br–C6H3)] (3: X = o-C6H4, 4: X = CH2CH2), and the corresponding ionic trinuclear counterpart of 4, [Cu{Fc–C(O)CHC(CH3)N–CH2CH2–NCH-(η6-2-O,5-Br–C6H3)RuCp*}][PF6] (5) (Fc = (η5-C5H5)Fe(η5-C5H4), Cp* = η5-C5Me5), have been explored. Single crystal X-ray diffraction analysis of complex 3 indicates a bowed structure of the unsymmetrical Schiff base scaffold. The Cu2+ ion is tetracoordinated in a square planar environment, with two nitrogen atoms and two oxygen atoms as donors. The EPR spectra of solid trinuclear complexes 5 and 7 (unsubstituted salicylidene ring and X = o-C6H4) at low temperature (68 K) consisted of fine-structure transitions (ΔMs = ±1) with zero-field splitting (ZFS) values of 0.0458 and 0.0415 cm−1, respectively, and a half-field signal (ΔMs = ±2) at ca. 1600 G, suggesting the formation of dimeric species (S = 1). In those dimers, Cu–Cu distances of 3.97 and 4.14 A, respectively, are computed from ZFS terms. The variable-temperature (2–300 K) magnetic susceptibilities of powdered samples of 5 and 7 have been measured, and an intermolecular antiferromagnetic interaction with exchange couplings of J = −1.05 and −0.65 cm−1, respectively, were found. The electrochemical behavior of both the neutral binuclear and ionic trinuclear compounds was investigated by cyclic voltammetry. Notably, the ability of the copper Schiff base core to transmit electronic effects between the two organometallic termini has been demonstrated by the observed anodic shift of the reversible voltammetric signal ascribed to the FeII/FeIII couple of the ferrocenyl donor fragment.

ICONE19-43912 ELECTROCHEMICAL CESIUM RECOVERY USING NANOPARTICLE INK OF METAL HEXACYANOFERRATE

Since Prussian blue (PB, or FeHCF) and its analogues (PBAs or MHCF (M=Ni, Zn, Co, Cu, etc.)) are well known as adsorbents of some ions or small molecules, especially, alkali metal cations such as Na^+, K^+, and Cs^+, these materials had been regarded as promising adsorbents to remove a radioactive Cs^+ from radioactive wastes. However, to adsorb a radioactive Cs^+ with MHCF causes the increase of radioactive wastes, so it is important to develop a reusable new system, or a controllable Cs^+ adsorbing/desorbing system. We succeeded in preparing nanoparticle inks of MHCFs, which are able to disperse into several solvents, and able to form films with the nanoparticle inks by conventional wet processes. Then we prepared the CuHCF nanoparticle films on Au/quartz substrates by a spin-coating method, and attempted to control the adsorption or desorption of alkali metal cations electrochemically. The electrochemical redox by cyclic voltammetry (CV) and adsorption/desorption measurement by electrochemical quartz crystal microbalance (EQCM) were carried out synchronously. For example, a copper substituted PBA, CuHCF films showed stable reversible redox signals for Na^+, K^+, and Cs^+ in the aqueous solution dissolving the corresponding nitrate salts (NaNO_3, KNO_3, and CsNO_3) as electrolytes. The redox potentials were different to each other, +0.55 V, +0.65 V, and +0.90 V (vs. SCE) for Na^+, K^+, and Cs^+, respectively. According to EQCM measurement, the mass changes followed by a cation adsorption/desorption occurred at the above-described potentials respectively and the ratios of mass showed almost 1:1:6 for Na^+:K^+:Cs^+. The difference of redox potentials and good duplicability of CV and EQCM signals suggests the possibility of electrochemically controllable cation adsorbing/desorbing systems.

A Phosphorylation Switch Regulates the Transcriptional Activation of Cell Cycle Regulator p21 by Histone Deacetylase Inhibitors

Histone deacetylase inhibitors induce cell cycle arrest and apoptosis in tumor cells and are, therefore, promising anti-cancer drugs. The cyclin-dependent kinase inhibitor p21 is activated in histone deacetylase (HDAC) inhibitor-treated tumor cells, and its growth-inhibitory function contributes to the anti-tumorigenic effect of HDAC inhibitors. We show here that induction of p21 by trichostatin A involves MAP kinase signaling. Activation of the MAP kinase signaling pathway by growth factors or stress signals results in histone H3 serine 10 phosphorylation at the p21 promoter and is crucial for acetylation of the neighboring lysine 14 and recruitment of activated RNA polymerase II in response to trichostatin A treatment. In non-induced cells, the protein phosphatase PP2A is associated with the p21 gene and counteracts its activation. Induction of p21 is linked to simultaneous acetylation and phosphorylation of histone H3. The dual modification mark H3S10phK14ac at the activated p21 promoter is recognized by the phospho-binding protein 14-3-3ζ, which protects the phosphoacetylation mark from being processed by PP2A. Taken together we have revealed a cross-talk of reversible phosphorylation and acetylation signals that controls the activation of p21 by HDAC inhibitors and identify the phosphatase PP2A as chromatin-associated transcriptional repressor in mammalian cells.