Inappropriate Signal Research Articles

Maternal exposure to dim light at night induces behavioral alterations in the adolescent and adult offspring Wistar rat.

Access to electric light has exposed living organisms to varying intensities of light throughout the 24h day. Dim light at night (DLAN) is an inappropriate signal for the biological clock, which is responsible for the circadian organization of physiology. During the gestational period, physiological adaptations occur to ensure a successful pregnancy and optimal fetal development. Environmental maternal conditions, such as disruptions of maternal circadian rhythms, could negatively affect offspring health. We have previously demonstrated that exposure of female Wistar rats to DLAN results in circadian, metabolic, and behavioral alterations. A relevant behavior during adolescence is social play, primarily regulated by the nucleus accumbens (NAc) which is crucial for the proper performance of important behaviors in adulthood. Throughout development, microglia are responsible for the remodeling of diverse brain regions via synaptic pruning. During adolescence, this process occurs within the NAc, where immune-mediated remodeling directly impacts social play behavior. This study investigated the effects of maternal exposure to DLAN or a light-dark cycle (LD) before (5weeks) and during the gestational period (21-23days) on the metabolism and behavior of offspring in adolescence and adulthood. Body mass was measured every 5 days from postnatal day 1 (PN1) to PN25 and every 10 days from PN40 to PN90; food consumption was monitored weekly from PN40 to PN90. Social play behavior was evaluated at PN40. The quantification and morphology of microglia in the NAc were measured on PN30. An open field test was conducted at PN60, and anhedonia test was assessed at PN90. Male and female offspring from mothers exposed to DLAN showed increased body mass gain at PN25. DLAN male offspring had lower food consumption, while DLAN females exhibited increased food consumption. In social play behavior, no differences were found between DLAN and LD female offspring. In contrast, DLAN male offspring exhibited a significant decrease in social play behavior compared to LD animals, which was associated with higher numbers of microglia in the NAc that had more ramified morphology. Importantly, at PN90, DLAN offspring presented increased anxiety-like behaviors. These results demonstrate that DLAN exposure induces intergenerational behavioral alterations that persist until adulthood.

Three-dimensional off-grid localization of incipient tip vortex cavitation using Bayesian inference

In this paper, we propose a 3-D source localization method to determine the incipient tip vortex cavitation (TVC) positions by constructing a signal model for the broadband off-grid cavitation. Subsequently, the conventional sparse Bayesian learning (SBL), whose performance is diminished owing to an inappropriate signal representation for the off-grid TVC by basis mismatch, was extended to solve the signal model via Taylor series and the block-sparse based broadband off-grid approach (off-grid BSBL). The off-grid BSBL was examined using synthetic and experimental cavitation tunnel data. Furthermore, its localization results were compared with those for conventional and adaptive beamformers and on-grid BSBL, which generally suffer from low resolutions and basis mismatch, respectively. When the off-grid BSBL was applied to chirp- and pop-type signals from incipient TVC, it determined the TVC positions near the top center of the propeller and provided the clearest localization results among the schemes considered.

Deep subclass alignment transfer network based on time–frequency features for intelligent fault diagnosis of planetary gearboxes under time-varying speeds

Vibration signals of planetary gearboxes have complex components and time-varying characteristics. As the unstable operation of planetary gearboxes leads to unbalanced data distribution within vibration signals, it is difficult to extract gearbox fault information hidden in a large amount of data. Therefore, fault diagnosis of planetary gearboxes under nonstationary conditions is highly challenging. For the past few years, intelligent diagnosis methods have been extensively studied in the fault diagnosis field. However, inappropriate signal representations, inadequate training samples, and data differences increase the difficulty of diagnosing planetary gearbox faults. To address the above issues, this paper proposes an intelligent diagnostic framework based on time–frequency features and a deep residual joint subclass alignment transfer network (DSATN) for planetary gearbox fault diagnosis under nonstationary conditions. One-dimensional vibration signals are converted into time–frequency representation through signal processing techniques to reflect the variation of vibration frequency components within the time–frequency domain with time. During network training, the DSATN evaluates the data distributions between relevant subclasses in source and target tasks by using the local maximum mean discrepancy. Also, it utilizes a nonlinear transformation to align the global data distributions between both tasks, thus improving the generalization of the trained model for small sample sets. The proposed method is validated through planetary gearbox experiments and achieves good fault classification in the time–frequency domain of nonstationary vibration signals. Different gear and planet bearing fault categories are successfully identified.

Blood pressure estimation from appropriate and inappropriate PPG signals using A whole-based method

Abstract Background and objective Blood pressure (BP) is one of the four vital signals that provides valuable medical information about the cardiovascular activity. In recent years, extensive studies have been conducted on non-invasive and cuff-less BP estimation using photoplethysmography (PPG) signals. PPG is a non-invasive optical method for measuring blood volume changes per pulse. In other words, the PPG waveform represents the mechanical activity of the heart. Methods In this paper, a new method for estimating the Mean Arterial Pressure (MAP), Diastolic Blood Pressure (DBP) and Systolic Blood Pressure (SBP) is proposed using only the PPG signal regardless of its shape (appropriate or inappropriate). Our proposed algorithm called whole-based, uses raw values of the PPG signal at a given time interval for estimating the BP. In other algorithms called parameter-based, use features which are extracted from PPG signals in time or frequency domain. These features related to precise spotting in the form of the PPG signal. In fact, compared to parameter-based methods, our algorithm is independent of the form of the PPG signal. Results Using the proposed algorithm, our results are completely met by the Association for the Advancement of Medical Instrumentation (AAMI) standard for both MAP and DBP estimations. The results are also very close to the standard boundary with an average error close to zero for SBP estimation. Also, according to the British Hypertension Society (BHS) standard, the proposed algorithm for DBP estimation got grade A, whereas it got grade B for estimation of MAP and got approximately grade C for SBP estimation. Conclusion The results demonstrate the applicability of the proposed algorithm in estimating BP noninvasively, cuff-less, calibration-free, and only by using the appropriate or inappropriate PPG signal.

Characteristics and mechanism of apogeotropic central positional nystagmus.

Here we characterize persistent apogeotropic type of central positional nystagmus, and compare it with the apogeotropic nystagmus of benign paroxysmal positional vertigo involving the lateral canal. Nystagmus was recorded in 27 patients with apogeotropic type of central positional nystagmus (22 with unilateral and five with diffuse cerebellar lesions) and 20 patients with apogeotropic nystagmus of benign paroxysmal positional vertigo. They were tested while sitting, while supine with the head straight back, and in the right and left ear-down positions. The intensity of spontaneous nystagmus was similar while sitting and supine in apogeotropic type of central positional nystagmus, but greater when supine in apogeotropic nystagmus of benign paroxysmal positional vertigo. In central positional nystagmus, when due to a focal pathology, the lesions mostly overlapped in the vestibulocerebellum (nodulus, uvula, and tonsil). We suggest a mechanism for apogeotropic type of central positional nystagmus based on the location of lesions and a model that uses the velocity-storage mechanism. During both tilt and translation, the otolith organs can relay the same gravito-inertial acceleration signal. This inherent ambiguity can be resolved by a 'tilt-estimator circuit' in which information from the semicircular canals about head rotation is combined with otolith information about linear acceleration through the velocity-storage mechanism. An example of how this mechanism works in normal subjects is the sustained horizontal nystagmus that is produced when a normal subject is rotated at a constant speed around an axis that is tilted away from the true vertical (off-vertical axis rotation). We propose that when the tilt-estimator circuit malfunctions, for example, with lesions in the vestibulocerebellum, the estimate of the direction of gravity is erroneously biased away from true vertical. If the bias is toward the nose, when the head is turned to the side while supine, there will be sustained, unwanted, horizontal positional nystagmus (apogeotropic type of central positional nystagmus) because of an inappropriate feedback signal indicating that the head is rotating when it is not.

Analysis, Mathematical Model and Selected Simulation Research of the GNSS Navigation Receiver Correlator

The article presents a mathematical model describing the physical phenomena occurring in the GNSS radio receiver. The main subunit which focused attention was the system of GNSS receiver correlator. The process of tracking and acquiring navigation signals processed in a navigational radio receiver was analyzed in a special way. Bearing in mind that all kinds of noise and interference get through to the signals processed in the receiver, the article attempts to develop a mathematical model of the signal reaching the receiver with noise and an inappropriate signal. On the basis of the mathematical model developed, the courses of acquisition and tracking processes of SIS signals in the presence of noise and interference signal in the form of a narrow and broadband signal are presented. The final part the paper presents the results of computer simulations. Although the results presented in the paper refer to a specific GNSS receiver, they may differ depending on the types of radio navigation devices.

Inappropriate implantable cardioverter-defibrillator shocks and signal jammers: First report of a new interference

Inappropriate implantable cardioverter-defibrillator shocks and signal jammers: First report of a new interference

COHESION AND COHERENCE IN ENGLISH EDUCATION STUDENTS’ THESIS

This study is entitled Cohesion and Coherence in English Education Students’ Thesis. The aim of this study is to describe the cohesion and coherence as wholeness aspect of discourse in English Education students’ thesis. This study is a qualitative research. The data sources in this study are the thesis of three students that were obtained by purposive sampling. Furthermore, analysis of the data was done by identifying and classifying the data that related to cohesion, based on the theory of Halliday and Hasan (1976), and related to coherence, based on the theory of Oshima and Hogue (1991). From analysis, it was found four things related to cohesion and coherence. First, the use of grammatical cohesion devices in thesis, which consists of reference, substitution, ellipsis, and conjunction; and the use of lexical cohesion devices, which consists of reiteration and collocation, was used in thesis. Second, the violence of cohesion device was found in grammatical devices, such as reference and conjunctions. Third, the use of coherence devices, which consists of key nouns repetition, use of pronouns, transition signal, and logical order of chronology was found in students’ thesis. Fourth, the cause of the error coherence of thesis consists of keyword repetition errors, inconsistent pronouns, inappropriate transition signal, grammatical errors, and inappropriate punctuation.

Development of a Dynamic Control Model for Oversaturated Arterial Corridor

In oversaturated condition, traffic queues that are unavoidable persist from cycle to cycle and the queue management capability is a critical feature in signal control. Inappropriate signal control and queue management strategies may lead to spillover and starvation with serious disruptive consequences. Compared with minimizing delay and stops in uncongested condition, the control policy in oversaturated condition comes to maximize system productivity and fully utilize storage capacity. This paper describes one dynamic control model to adjust the green phase duration, offset and cycle length by considering the saturation level, the queue length management and propagation along the arterial corridor. A VISSIM simulation test of one arterial corridor in City of Edmonton is used to validate the efficiency of the proposed control model.

Explaining cost overruns of large-scale transportation infrastructure projects using a signalling game

Strategic behaviour is one of the main explanations for cost overruns. It can be theoretically supported by agency theory, in which strategic behaviour is the result of asymmetric information between the principal and agent. This article gives a formal account of this relation by a signalling game. This is a game with incomplete information which considers the way in which parties anticipate upon other parties’ behaviour in choosing a course of action. The game shows how cost overruns are the result of an inappropriate signal. This makes it impossible for the principal to distinguish between the types of agents, and hence, allows for strategic behaviour. It is illustrated how cost overruns can be avoided by means of two policy measures, e.g. an accountability structure and benchmarking.

Evaluation of Driver Behavior in Type II Dilemma Zones at High-Speed Signalized Intersections

Unlike traditional Type I dilemma zones, where inappropriate signal timings or detector placements restrict the ability of motorists to safely proceed through the intersection or safely stop in advance, Type II dilemma zones are attributed to driver difficulties in decision making. Type II issues become more prevalent at high-speed intersections, which have greater variability in operating speeds and greater potential for serious crashes. Although several features related to Type II dilemma zones are known, inconsistency remains in the application of the boundary definitions. This research characterizes driver behavior and comprehension related to Type II dilemma zones for the purpose of defining these boundary conditions. Empirical observations of 10 high-speed signalized intersection approaches were conducted, and the analyses of the observed driver behavior resulted in an expanded understanding of how and where drivers make their decision to stop or proceed when approaching a signal. Specifically, distributions of vehicle location and driver behavior were examined using multiple boundary definitions, and in several instances the distributions of driver behaviors varied depending on the dilemma-zone definition employed.

Regulation of mixed-lineage kinase activation in JNK-dependent morphogenesis

Normal cells respond appropriately to various signals, while sustaining proper developmental programs and tissue homeostasis. Inappropriate signal reception, response or attenuation, can upset the normal balance of signaling within cells, leading to dysfunction or tissue malformation. To understand the molecular mechanisms that regulate protein-kinase-based signaling in the context of tissue morphogenesis, we analyzed the domain requirements of Drosophila Slpr, a mixed-lineage kinase (MLK), for Jun N-terminal kinase (JNK) signaling. The N-terminal half of Slpr is involved in regulated signaling whereas the C-terminal half promotes cortical protein localization. The SH3 domain negatively regulates Slpr activity consistent with autoinhibition via a conserved proline motif. Also, like many kinases, conserved residues in the activation segment of the catalytic domain regulate Slpr. Threonine 295, in particular, is essential for function. Slpr activation requires dual input from the MAP4K Misshapen (Msn), through its C-terminal regulatory domain, and the GTPase Rac, which both bind to the LZ-CRIB region of Slpr in vitro. Although Rac is sufficient to activate JNK signaling, our results indicate that there are Slpr-independent functions for Rac in dorsal closure. Finally, expression of various Slpr constructs alone or with upstream activators reveals a wide-ranging response at the cell and tissue level.

Neuronal Activity in Rat Barrel Cortex Underlying Texture Discrimination

Rats and mice palpate objects with their whiskers to generate tactile sensations. This form of active sensing endows the animals with the capacity for fast and accurate texture discrimination. The present work is aimed at understanding the nature of the underlying cortical signals. We recorded neuronal activity from barrel cortex while rats used their whiskers to discriminate between rough and smooth textures. On whisker contact with either texture, firing rate increased by a factor of two to ten. Average firing rate was significantly higher for rough than for smooth textures, and we therefore propose firing rate as the fundamental coding mechanism. The rat, however, cannot take an average across trials, but must make an immediate decision using the signals generated on each trial. To estimate single-trial signals, we calculated the mutual information between stimulus and firing rate in the time window leading to the rat's observed choice. Activity during the last 75 ms before choice transmitted the most informative signal; in this window, neuronal clusters carried, on average, 0.03 bits of information about the stimulus on trials in which the rat's behavioral response was correct. To understand how cortical activity guides behavior, we examined responses in incorrect trials and found that, in contrast to correct trials, neuronal firing rate was higher for smooth than for rough textures. Analysis of high-speed films suggested that the inappropriate signal on incorrect trials was due, at least in part, to nonoptimal whisker contact. In conclusion, these data suggest that barrel cortex firing rate on each trial leads directly to the animal's judgment of texture.

Gene expression profiling of Hfe -/-liver and duodenum in mouse strains with differing susceptibilities to iron loading: identification of transcriptional regulatory targets of Hfe and potential hemochromatosis modifiers

BackgroundHfe disruption in mouse leads to experimental hemochromatosis by a mechanism that remains elusive. Affymetrix GeneChip® Mouse Genome 430 2.0 microarrays and bioinformatics tools were used to characterize patterns of gene expression in the liver and the duodenum of wild-type and Hfe-deficient B6 and D2 mice (two inbred mouse strains with divergent iron loading severity in response to Hfe disruption), to clarify the mechanisms of Hfe action, and to identify potential modifier genes.ResultsWe identified 1,343 transcripts that were upregulated or downregulated in liver and 370 in duodenum of Hfe-/- mice, as compared to wild-type mice of the same genetic background. In liver, Hfe disruption upregulated genes involved in antioxidant defense, reflecting mechanisms of hepatoprotection activated by iron overload. Hfe disruption also downregulated the expression of genes involved in fatty acid β-oxidation and cholesterol catabolism, and of genes participating in mitochondrial iron traffic, suggesting a link between Hfe and the mitochondrion in regulation of iron homeostasis. These latter alterations may contribute to the inappropriate iron deficiency signal sensed by the duodenal enterocytes of these mice, and the subsequent upregulation of the genes encoding the ferrireductase Dcytb and several iron transporters or facilitators of iron transport in the duodenum. In addition, for several genes differentially expressed between B6 and D2 mice, expression was regulated by loci overlapping with previously mapped Hfe-modifier loci.ConclusionThe expression patterns identified in this study contribute novel insights into the mechanisms of Hfe action and potential candidate genes for iron loading severity.

MTOR, translational control and human disease

Many human diseases occur when the precise regulation of cell growth (cell mass/size) and proliferation (rates of cell division) is compromised. This review highlights those human disorders that occur as a result of inappropriate cellular signal transduction through the mammalian target of rapamycin (mTOR), a major pathway that coordinates proper cell growth and proliferation by regulating ribosomal biogenesis and protein translation. Recent studies reveal that the tuberous sclerosis complex (TSC)-1/2, PTEN, and LKB1 tumor suppressor proteins tightly control mTOR. Loss of these tumor suppressors leads to an array of hamartoma syndromes as a result of heightened mTOR signaling. Since mTOR plays a pivotal role in maintaining proper cell size and growth, dysregulation of mTOR signaling results in these benign tumor syndromes and an array of other human disorders.

Early consequences of 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure on the activation and survival of antigen-specific T cells.

TCDD is a potent immunotoxicant that suppresses adaptive immunity by mechanisms that are not well defined. To gain insight at the level of the T cell, we used the DO11.10 transgenic T-cell receptor (TCR) mouse model in an adoptive transfer approach to characterize the influence of TCDD on the responsiveness of antigen-specific CD4+ T cells in vivo. Flow cytometry was used to track the response of the OVA-specific transgenic CD4+ T cells in syngeneic recipients using an antibody specific for the transgenic TCR (KJ1-26 [KJ]). Consistent with a previous report, exposure of the recipient mice to TCDD (15 microg/kg po) did not alter the initial expansion of the CD4+KJ+ T cells in the spleen following immunization with OVA but resulted in a significant decline in the number of cells present on and after day 4. The degree of decline was dependent on the dose of TCDD. On day 3 after OVA injection, a higher percentage of the CD4+KJ+ T cells in the spleens of TCDD-treated mice had down-regulated the expression of CD62L, a phenotype associated with T-cell activation. Also on day 3, an increased number of CD4+KJ+ T cells were found in the blood of TCDD-treated mice. However, as in the spleen, the number of CD4+KJ+ T cells in the blood rapidly declined on day 4. CD4+KJ+ T cells in both the spleen and blood of TCDD-treated mice failed to up-regulate CD11a, an adhesion molecule important for sustained interaction between T cells and DC whereas the up-regulation of the adhesion molecule CD49d was not altered. Based on analysis of cell division history, CD4+KJ+ T cells in vehicle-treated mice continued to divide through day 4 whereas CD4+KJ+ T cells in TCDD-treated mice showed no further division after day 3. Increased annexin V staining on CD4+KJ+ T cells in TCDD-treated mice was also observed but not until days 5 and 6. Fas-deficient CD4+KJ+ T cells were depleted from the spleen of TCDD-treated mice in a manner similar to wild-type CD4+KJ+ T cells, suggesting that Fas signaling does not play a critical role in this model. On the other hand, gene array analysis of purified CD4+KJ+ T cells on day 3 showed that the expression of several genes associated with cell survival/death were altered by TCDD. Taken together, the results are consistent with our hypothesis that TCDD provides an early but inappropriate activation signal to the antigen-specific T cells that allows, and possibly enhances, the initial activation and proliferation of the T cells, yet at the same time, interferes with the vital expression of certain adhesion/costimulatory molecules that serve to enhance the survival of the T cells. These changes result in truncated proliferation, increased T-cell death, and suppression of the adaptive immune response.

Vibroacoustic Loads On Spacecraft Antennae: Analysis And Test Correlations

The acoustic load during launch is one of the dimensioning cases of spacecraft structures, especially demanding for large antenna reflectors. Current specifications rely on the diffuse field idealisation, while tests are actually performed in reverberating chambers, leading to discrepancies between predicted and measured responses. Most of these are due to the limited capabilities of analytical tools for industrial applications and the testing facilities, particularly when dealing with the modelling or control of the acoustic inputs. However, as shown in this paper, some sources of correlation errors are inappropriate signal processing methods, that do not take into account the physical nature of the loads and the fluid-structure coupling. In particular, digital filtering techniques applied to fine resolution power spectral densities are proposed, in order to better retain the effect of cavity modes, instead of the octave-fraction bands approach. This is of interest when analysing the low frequency range, in which the most important contributions to structural stresses usually appear, depending on the size in terms of pressure blocking, the structural impedance, the acceptance of eigen-mode shapes and the radiation coupling. Several industrial examples are studied, providing insight into typical results, the nature of the discrepancies and some possible solutions.

Inactivation of the hemochromatosis gene differentially regulates duodenal expression of iron-related mrnas between mouse strains

Hfe knockout mice, like patients with hereditary hemochromatosis, have augmented duodenal iron absorption and increased iron deposition in hepatic parenchymal cells. The goals of the present study were to gain further insight into the control of iron absorption by comparing the transcript levels of iron-related genes in the duodenum of DBA/2 Hfe-/- mice, susceptible to iron loading, and wild-type controls, and to test whether variations in the duodenal expression of these messengers contribute to the DBA/2 and C57BL/6 strain differences in the severity of hepatic iron loading. Expression of the different transcripts was quantified by real-time polymerase chain reaction. The 2 strains differ strikingly, not only in the severity of hepatic iron loading, but also in the duodenal expression of iron-related genes. In DBA/2 Hfe-/- mice, increased intestinal iron absorption results from the concomitant up-regulation of the Dcytb, DMT1, and FPN1 messengers. No increase in the expression of these messengers is seen in C57BL/6 Hfe-/- mice. The up-regulation of these transcripts suggests that an inappropriate iron-deficiency signal is sensed by the duodenal enterocytes, leading to an enhanced ferric reductase activity and the increase of duodenal iron uptake and transfer to the circulation. The genes modifying the hemochromatosis phenotype probably act by modifying the expression of these 3 messengers.

Decreased CD44v6 Expression in Lamina Propria Lymphocytes of Patients with Inflammatory Bowel Disease

Splice variants of the glycoprotein CD44 are transiently expressed on lymphocytes during T cell activation. Increased expression of CD44v6 on peripheral blood lymphocytes (PBL) of patients with inflammatory bowel disease (IBD) was described recently. The aim of this study was therefore to characterize CD44v6 expression on CD4(+) lamina propria lymphocytes (LPL) of patients with active IBD in comparison to controls. CD44v6 expression on CD4(+) LPL (n = 19) of controls and patients with active IBD (Crohn's disease n = 14, ulcerative colitis n = 15) was analyzed by flow cytometry and compared to that on autologous PBL. Thereby, in vitro regulation of CD44v6 on LPL and PBL via CD3 and CD2 and the costimulatory signal B7-1 was examined. In addition, the role of protein kinase C (PKC) in CD44v6 expression was tested. CD44v6 expression was increased in CD4(+) LPL (median, 45%) compared to PBL (median, 38%). Surprisingly, in IBD CD44v6 was downregulated on CD4(+) lamina propria T cells, irrespective of their state of inflammation (median, 28%). CD44v6 expression on LPL was not upregulated upon CD3 activation alone but following costimulation with B7-1. However, CD2-mediated T cell activation sufficiently induced upregulation of CD44v6 on LPL and PBL. In our study, downregulation of CD44v6 on LPL of patients with IBD was not due to defective PKC activation. Taken together, these data indicate that decreased CD44v6 expression on LPL in IBD might be a feature of an inappropriate costimulatory signal in T cell activation.

In vitro human immunodeficiency virus eradication by autologous CD8(+) T cells expanded with inactivated-virus-pulsed dendritic cells.

Despite significant immune recovery with potent highly active antiretroviral therapy (HAART), eradication of human immunodeficiency virus (HIV) from the bodies of infected individuals represents a challenge. We hypothesized that an inadequate or inappropriate signal in virus-specific antigen presentation might contribute to the persistent failure to mount efficient anti-HIV immunity in most HIV-infected individuals. Here, we conducted an in vitro study with untreated (n = 10) and HAART-treated (n = 20) HIV type 1 (HIV-1) patients which showed that pulsing of monocyte-derived dendritic cells (DC) with aldrithiol-2-inactivated autologous virus resulted in the expansion of virus-specific CD8(+) T cells which were capable of killing HIV-1-infected cells and eradicating the virus from cultured patient peripheral blood mononuclear cells independently of the disease stages and HAART response statuses of the patients. This in vitro anti-HIV effect was further enhanced by the HIV protease inhibitor indinavir (at a nonantiviral concentration), which has been shown previously to be able to up-regulate directly patient T-cell proliferation following immune stimulation. However, following a 2-day treatment with culture supernatant derived from immune-activated T cells (which mimics an in vivo environment of HIV-disseminated and immune-activated lymphoid tissues), DC lost their capacity to present de novo inactivated-virus-derived antigens. These findings provide important information for understanding the establishment of chronic HIV infection and indicate a perspective for clinical use of DC-based therapeutic vaccines against HIV.