Exploration of extreme environments, such as planetary surfaces and subterranean lava tubes, poses significant challenges for space robotics, particularly in navigation and traversability analysis. These tasks require high autonomy under stringent computational and power constraints, which limits the applicability of many modern Visual SLAM methods developed for terrestrial applications. In this paper, we present a lightweight Visual SLAM system for Unmanned Ground Vehicles (UGVs) tailored to space-relevant scenarios. The system integrates a computationally efficient front-end with a sparsification-enhanced back-end and incorporates dense 3D reconstruction to support traversability mapping. We evaluate our system alongside state-of-the-art navigation methods using multiple sensing modalities (Camera, Camera/IMU, LiDAR) on two representative datasets: the Martian Terrain dataset and the Mine Museum dataset, which emulates lava tube environments. Results demonstrate that our system achieves localization accuracy and 3D reconstruction quality comparable to existing approaches, while running in real time on low-power embedded platforms, such as a Raspberry Pi 4, and supporting semi-autonomous navigation with human oversight, consistent with current space mission operations. All datasets and code are publicly available, including the Martian Terrain and Mine Museum datasets, as well as the Visual SLAM and Traversability Mapping implementations, facilitating reproducibility and supporting further research in planetary robotics.

Visual navigation has achieved significant maturity in recent decades. Indirect methods relying on sparse feature extraction, have become a standard for state estimation. However, these techniques are not frequently utilized as inputs for path planning due to the sparse nature of their maps. To address this limitation, this paper introduces a method to densify the sparse map generated by local indirect Visual or Visual Inertial Odometry (VO-VIO) based on factor graph sparsification. The intended application is the autonomous navigation of Unmaned Ground Vehicles (UGV) in planetary environments without the need to perform computationally expensive dense stereo vision. An incremental 3D mesh is built upon a 2D triangulation of the features identified by the VO. A photometric consistency check is conducted on each triangle, resulting in a triangle soup rather than a manifold mesh. A dense point cloud is then extracted by casting rays on the triangle soup and using the most reliable triangle to compute depth. Geometric traversability information can subsequently be derived from this point cloud to aid UGV navigation. This system is evaluated on a dataset recorded on an artificial Martian terrain and demonstrates superior performance compared to a similar method from the state-of-the-art.

IntroductionThe COVID-19, triggered by the SARS-CoV-2 virus, has varied clinical manifestations, ranging from mild cases to severe forms such as fatal pneumonia and acute respiratory distress syndrome (ARDS). Disease severity is influenced by an exacerbated immune response, characterized by high pro-inflammatory cytokine levels. Inhibition of AKT can potentially suppress pathological inflammation, cytokine storm and platelet activation associated with COVID-19. In this study, we aimed to investigate the rs2494746 and rs1130214 variants in the AKT1 gene associated with severe COVID-19 outcomes.MethodsPeripheral blood samples and sociodemographic data from 508 individuals with COVID-19, measuring plasma cytokine concentrations using ELISA and genotyped the AKT1 variants.ResultsThe rs2494746-C allele was associated with severity, ICU admission, and death from COVID-19. The C allele at rs1130214 was linked to increased TNF and D-dimer levels. Moreover, both variants exhibited an increased cumulative risk of disease severity, ICU admission, and mortality caused by COVID-19. In the predictive analysis, the rs2494746 obtained an accuracy of 71%, suggesting a high probability of the test determining the severity of the disease.DiscussionOur findings contribute to understanding the influence of the AKT1 gene variants on the immunological damage in individuals infected with SARS-CoV-2.

Introduction In the last decade, therapeutic advances have led to an increase in the overall survival of patients with multiple myeloma (MM); however, the disease remains incurable. Therapeutic protocols combining alkylating agents, immunomodulators, proteasome inhibitors, and immunotherapy induce an immunological shift that is still not fully understood. Objective The aim of this study was to quantify lymphocyte subpopulations and B-cell subsets in patients with newly diagnosed MM (NDMM) eligible for autologous stem cell transplant (ASCT) using first-line therapy with cyclophosphamide, thalidomide, and dexamethasone combined with daratumumab (Dara-CTd). Methodology Between 2018 and 2022, 23 NDMM patients had their lymphocyte profiles analyzed at 5 distinct time points: at diagnosis, after induction therapy, after 2 consolidation cycles post-ASCT, before maintenance therapy, and 1 year after the start of the maintenance phase. Flow cytometry was used to detect lymphocyte subsets by surface molecules, including CD3, CD4, CD5, CD8, CD16, CD19, CD20, CD38, CD45, and CD56 in the scatter plot. B cells were isolated, and subpopulations (naïve B cells, non-class-switched memory B cells, class-switched memory B cells, IgD-CD27 memory B cells, and plasmablasts) were detected by CD20, CD24, CD27, CD38, CD45, and IgD. Statistics were performed using the SPSS® v25.0. Results The median age was 58 (range: 37-67), and 57% were female. It was observed that the treatment induced significant changes in the lymphocyte profile, with emphasis on the decrease in B cells and NK cells (P ≤ .05). The composition of the B cell subsets changed significantly throughout the treatment. T cells significantly decreased after the induction phase but recovered soon post-ASCT. Although not statistically significant, higher lymphocyte counts were observed with higher overall survival and undetectable measurable residual disease by next-generation flow (NGF). Conclusion The present study confirmed that Dara-CTd induced a decrease in the number of different lymphocyte populations (T, B, and NK cells) after induction therapy with Dara-CTd. The T cell number recovered after 2 consolidation cycles post-ASCT, but B and NK cells remained at low levels during treatment with slow recovery.

Background: The CTD combination have both an immunomodulatory and immunosuppressive activity on multiplemyeloma (MM) patients (pts) treatment. The advance of immunotherapy has been demonstrated by the development ofnew agents like anti CD38-antibody Dara, that are increasing the overall and progression-free survival of MM pts. Daraeffect on the immune system was already described, but few studies analyzed specifically lymphocytes population. Wehypothesized that Dara-CTD combination could impact on lymphocytes subsets during treatment.Aims: The primary endpoint was to quantify subpopulations of lymphocytes in pts with newly diagnosed multiplemyeloma (NDMM) transplant eligible (TE) pts, during Dara-CTD treatment phases (induction, consolidation andmaintenance). Secondary endpoint was to describe B cells subsets during the same phases Methods: Peripheral blood of 14 pts at four different time points was collected: at diagnose, after four cycles of Dara-CTD, after two consolidation cycles post-autologous stem cell transplantation (ASCT) and before maintenance therapy.Flow cytometry was used to detect lymphocyte surface molecules including CD3, CD4, CD5, CD8, CD16, CD19, CD20,CD38, CD45 and CD56 in the scatter plot. B cells were isolated and subpopulations (naïve B cells, non-class switchedmemory B cells, class switched memory B cells, IgD-CD27- memory B cells and plasmablasts) were detected by CD20,CD24, CD27, CD38, CD45 and IgD. Statistics was performed using the SPSS®v25.0 Results: The pts median age was 55 range (41-65) years old, and 57% were female. The median of T, B and NKlymphocytes subsets at diagnosis were 1153 x 10³/μL, 205x 10³/μL and 284 x 10³/μL cells, respectively. After four cyclesof Dara-CTD the median of T, B and NK cells dropped significantly to 889 x 10³/μL, 12 x 10³/μL and 11 x 10³/μL,respectively (p<0.05). The number of the cells after two consolidation cycles post-ASCT, showed T cells full recovery(1087 x 10³/μL) while B and NK cells had weakly reconstitution (15 x 10³/μL and 34 x 10³/μL, respectively). Beforemaintenance therapy, the median of T, B and NK cells were 1456 x 10³/μL, 24 x 10³/μL and 33 x 10³/μL, respectively.Regarding B cell population, the median of naïve B cell decreased after 4 induction cycles from 32 x 10³/μL to 1 x 10³/μL.Then, after two consolidation cycles post-ASCT the number of B cell increased to 14 x 10³/μL and to 18 x 10³/μL beforemaintenance Summary/Conclusion: Lymphopenia have been shown with different protocols using Dara as single agent or incombination. The present study confirmed that there is a decrease in the number of different lymphocytes populations (T,B and NK) after induction therapy with Dara-CTD. The T cells number recovery after two consolidation cycles post-ASCT,but B and NK cells remain low after the same period. There was a slowly but continuously recovering of B and NK cells,suggesting that Dara-CTD combination allows lymphocytes reconstitution. Analyzing the B cells subpopulations, thenaive B cell was the first to show a more significant recovery, although it was below the reference range (33 – 259). Inconclusion, this is the first study that report the lymphocyte profile during Dara-CTD treatment. This preliminary datasuggest that Dara-CTD induces general lymphopenia on (T, B and NK) populations after induction phase. It wasidentified that T cells recovery was complete after two consolidations cycles while the recovery of B and NK cells wasslowly but continuously.

Visual navigation has become a standard in robotic applications with the emergence of robust and versatile algorithms. In particular, Visual Odometry (VO) has proven to be the most reliable navigation solution for space missions to estimate an unmanned vehicle's motion and state. Lava Tubes exploration is one of the recent challenges in this field of applied robotics. VO in this scenario requires more robustness to poor lighting conditions while keeping a low computational cost. We propose investigating an indirect bi-monocular VO based on sliding-window optimization in such a context. It focuses on maintaining the sparsity of the problem while keeping the information of the marginalized frames to reduce the computational burden. Different sparse graph topologies are studied to encode information from the past and are evaluated on accuracy and computation load. The best method retained is then compared to state-of-the-art systems on real data under extreme illumination conditions and reaches similar accuracy results at a lower computational cost.

—With the discovery of potential extra terrestrial Lava Tubes, their exploration has become a hot topic for space agencies. Autonomous robots are needed to answer many questions that are raised by their discovery. We propose in this paper to discuss the design of a feasible and performing Visual Odometry (VO) solution to enable a safe navigation for spatial rovers in such environment. For this, we propose a modular bi-monocular indirect approach adapted to every camera model while keeping the processing load as low as possible. This paper presents an experimental study in a self illuminated cave environment. We focus on keypoint / descriptor pairs, feature association modalities and camera models. We show results on both real and simulated scenario to enhance the comprehension of methods widely used in the robotic community and their adaptation to such environment. Results from these experiments will be used to design a visual based navigation adapted for extra terrestrial Lava Tubes exploration.

Trichlorophenols (TCPs) are used as chemical intermediates in the manufacture of a wide range of agricultural and industrial products. Previous studies have shown that 2,4,5‐TCP is the most potent nephrotoxicant in vitro of the six TCP isomers in isolated kidney cells (IKCs) from male Fischer 344 rats. It was also determined that 2,4,5‐TCP nephrotoxicity was attenuated by piperonyl butoxide, a non‐specific cytochrome P450 (CYP) inhibitor. The purpose of this study was to determine which CYPs might play a role in 2,4,5‐TCP nephrotoxicity in vitro in IKCs from male Fischer 344 rats. IKCs (~4 million/ml, 3 ml) were incubated with a selective CYP inhibitor or vehicle prior to addition of 2,4,5‐TCP (0.5 mM) or dimethyl sulfoxide (DMSO, 2,4,5‐TCP vehicle) for 60 min with shaking at 37oC under a 95% oxygen/5% carbon dioxide atmosphere. Cytotoxicity was determined by measuring lactate dehydrogenase (LDH) release at the end of the incubation period. 2,4,5‐TCP‐induced cytotoxicity was completely attenuated by CYP inhibitors sulfaphenazole (CYP2C11) and thiotepa (CYP2B6). 2,4,5‐TCP cytotoxicity was also reduced by pretreatment with omeprazole (CYP2C19), DEDTCA (CYP2C/E), or isoniazid (CYP2E1). The least effective CYP inhibitor at reducing 2,4,5‐TCP cytotoxicity was oleandomycin (CYP3A). These results suggest that CYPs play a role in 2,4,5‐TCP nephrotoxicity in vitro with CYP2C11 and CYP2B6 being major contributors to promoting 2,4,5‐TCP cytotoxicity. The mechanism by which these and other CYPs promote 2,4,5‐TCP nephrotoxicity remains to be determined.

Dichlorobenzenes (DCBs) are commonly used as chemical intermediates in the manufacture of a wide range of agricultural, industrial and pharmaceutical products. Previous studies have shown that 1,4-DCB can induce nephrotoxicity in male rats characterized as α2u-globulin nephropathy. Initially, 1,4-DCB binds to α2u-globulin at extra-renal sites. The 1,4-DCB-protein complex then accumulates in kidney and causes protein droplet formation, ultimately leading to cell death and/or eventually tumor formation. The purpose of this study was to explore the direct cytotoxic effects of the three DCB isomers in isolated kidney cells (IKCs) from male Fischer 344 rats. IKCs (~4 million/ml, 3 ml) were incubated with a DCB (0.25-1.0 mM) or dimethyl sulfoxide (DMSO, vehicle) for 30 or 60 min with shaking at 37oC under a 95% oxygen/5% carbon dioxide atmosphere. Cytotoxicity was determined by measuring lactate dehydrogenase (LDH) release. In separate experiments, IKCs were pretreated with an antioxidant (ascorbate, 1.0 mM; N-acetyl-L-cysteine, 2.0 mM; glutathione, 1.0 mM) prior to the addition of 1,4-DCB (0.5 mM) and followed by a 60 min co-incubation. 1,4-DCB increased LDH release at all times and concentrations tested. 1,3-DCB increased LDH release at 0.5 mM or greater at both time points, while 1,2-DCB only increased LDH release at 0.5 mM or greater at 60 min. Thus, the order of decreasing nephrotoxic potential was 1,4-DCB > 1,3- DCB > 1,2-DCB. Pretreatment with any of the antioxidants tested attenuated 1,4-DCB nephrotoxicity. These results indicate that DCBs can induce nephrotoxicity in vitro without the presence of extra-renal α2u-globulin, 1,4-DCB is the most potent nephrotoxicant among the three DCB isomers in IKCs, and free radicals play a role in DCB nephrotoxicity.

The Mobile Asteroid Surface Scout (MASCOT), an Asteroid Lander carried by the Hayabusa2 spacecraft, successfully landed on the Near-Earth Asteroid (162173) Ryugu on October 03, 2018. Thereby accomplishing the first-ever landing of a European spacecraft on the surface of this type of celestial body. MASCOT was a prototype design of a new class of nano-size surface science packages for the exploration of small solar system bodies. The very low gravity (thus, very low escape velocity) of the target body required the design of a miniaturized deployment mechanism with a relatively small, well-reproducible separation velocity. In addition, the mechanism also had to safely restrain the lander to the mother spacecraft during the launch and its 3.5-year cruise phase. In this paper, we describe in detail the design, numerical analysis and test of this newly developed separation mechanism. Furthermore, we compare the mechanism to other existing deployment systems and verify its performance with two independent analysis methods using actual flight data taken during the ultimate flight activation event, which initiated the successful delivery and surface operation of the MASCOT asteroid lander.

Background: CD38-targeting antibody Daratumumab (Dara) has been demonstrating significant improvement in (MM) patient's survival. Cyclophosphamide (C), thalidomide (T) and dexamethasone (D) - (CTd) is one of the most used induction protocols worldwide and the MAX-Dara study was the first that combine Dara-CTd as induction for (NDMM) (TE) patients. We hypothesized that this new combo + autologous stem cell transplantation (ASCT) could affect the quantitative recovery of distinct lymphocytes subsets. Objective: Primary endpoint was to quantify lymphocytes subpopulations in (NDMM) (TE) patients at different treatment phases. Secondary endpoint was to evaluate B cells subsets at same times. Methods: Peripheral blood of 10 NDMM TE patients was collected at three different moments: at diagnose, after 4 induction cycles and after two consolidation cycles post- (ASCT). Dara-CTd protocol was for up to four 28-day induction cycles: C-500mg per oral (PO) d 1,8 and 15, T at 100-200mg PO d 1 to 28, Dex at 40mg PO d 1,8,15 and 22 and Dara 16mg/Kg/dose IV on d 1,8,15 and 22 during cycles 1 - 2 and every other week in cycles 3 - 4, followed by ASCT. Consolidation was started at D+30 after ASCT and all patients received up to four 28-day consolidation cycles: Dara 16mg/Kg and (D) at 40mg every other week, associated with T at 100mg PO d 1 - 28. Dara 16mg/Kg was used monthly as maintenance until progression or limiting toxicity. Flow cytometry was used to detect lymphocyte surface by CD3, CD4, CD5, CD8, CD16, CD19, CD20, CD38, CD45 and CD56 in the scatter plot. B cells were isolated and subpopulations (naïve B cells, class and non-class switched memory B cells, , IgD-CD27- memory B cells and plasma blasts) were detected by CD20, CD24, CD27, CD38, CD45 and IgD. Statistical analysis was performed using the SPSS® v25.0. Results: The median number of lymphocytes subsets at diagnosis were 1139 x 10³/μL for T cells, 155 x 10³/μL for B cells and 284 x 10³/μL for NK cells. After four cycles of Dara-CTD the median number of T, B and NK cells had dropped to 834, 7.5 and 8.0 x 10³/μL respectively (p<0.05). After two consolidation cycles post-ASCT, the T cells showed full reconstitution (1246 x 10³/μL) while B cells and NK cells had weakly reconstitution (20 x 10³/μL and 33 x 10³/μL, respectively). Regarding B cells subpopulations, the median B cell naïve numbers decreased from 32 x 10³/μL to 1 x 10³/μL (after 4 cycles), and recovery post-ASCT to 14 x 10³/μL. Class and non-class switched memory B cells numbers decreased after induction from 30 to 3.5 x 10³/μL and 37 to 2.0 x 10³/μL respectively. These subpopulations recovery after ASCT+ two consolidation cycles were not observed. Discussion: Different cells populations expresses CD38 antigen in their surface and depending on that, transitional lymphocytes counts reduction have been shown with different protocols using Dara. The present study confirmed that there is a decrease on total lymphocytes numbers after Dara- use. After two consolidation cycles post-ASCT, T cells counts had been recovered, while NK and B cells had a slightly recovery suggesting that Dara-CTD combination had a slighted negative impact in those lymphocytes' reconstitution. Concerning specifically B cells populations, we found that naive B cell was the first to showed faster recovery, although it was still below the reference range (33 - 259 x 10³/μL). Conclusion: This is the first study that reported lymphocyte profile with Dara plus CTD protocol. The preliminary data suggests that Dara-CTD reduces all lymphocytes populations after induction phase, but after ASCT followed by two consolidations cycles full reconstitution of T cells and slight recovery of B and NK cells was observed. Disclosures De Queiroz Crusoe: Janssen: Research Funding.

Hayabusa-2, a JAXA mission, reached C-type asteroid (162173) Ryugu in June 2018. Hayabusa2 carried MASCOT (Ho et al., 2016), a small lander developed by DLR and CNES. The goal of MASCOT was to perform in situ measurements on the surface of the asteroid by means of its four scientific instruments, substantially contributing in this way to the overall scientific return of Hayabusa2 mission. MASCOT landing occurred the October 3, 2018. After its release by Hayabusa2 spacecraft, the MASCOT lander experienced 17 min of descent and bounces. Then after stabilization it collected measurements during 17 h, visiting three slightly different sites. A comprehensive knowledge of MASCOT's attitudes on the various moment of its mission is essential for the understanding of the science data gathered by the scout. CNES flight dynamics team was involved in the reconstruction of MASCOT landing trajectory and attitude. This paper presents the attitude reconstruction of MASCOT during its descent and on its second landing site. The reconstruction used as inputs the housekeeping data generated by the 6 Photo Electric Cells of MASCOT, as well as the images acquired by Hayabusa2 ONC camera and the MASCAM camera. The assessment was very complex but we determined the attitude with a mean accuracy around 10 degrees during descent and 8 degrees when MASCOT was stable once the second landing site was successfully reached. Nevertheless, for the other phases - bounces, first landing site and last landing site-the lander attitude is still undetermined.

Persistent immune actiation is associated with innadequate immune recovery in HIV‐patients. This study assessed the relationship between frequency of expression of cell activation markers (CD38 and HLADR) and presence of oral lesions in HIV‐1 infected patients. Fifty‐seven HIV‐infected persons, undergoing antiretroviral treatment, were divided into three groups, according to the number of CD4+ T cells and CD4+/CD8+ ratio: adequate, partial, and inadequate immune restauration. All patients underwent full mouth assessments for saliva flow measurement, oral mucosal lesion, periodontal disease, and severity of periodontitis. Immune activation markers levels were compared according to three groups of periodontal disease (“No periodontal disease,” “gingivitis,” and “periodontitis”). Oral mucosal lesions (P = 0.03) and peridodontal disease (P = 0.03) were associated with lower CD4+/CD8+ ratio. Patients with oral mucosal lesions had significantly higher median levels of HLADR and CD38 markers in all T‐lymphocytes populations than patients without oral lesions. Patients with gingivitis and with periodontitis presented significantly higher median levels of CD3+ HLADR+, CD4+ HLADR+, CD8+ HLADR+, and CD3+ CD38+ and significantly lower CD4+/CD8+ ratio than patients with no periodontal disease. Increased levels of HLADR and CD38 expressions in peripheral blood were associated with oral lesions in HIV‐positive patients. Periodontal disease was associated with HLADR expression.

On the 12th of November 2014, The Rosetta Lander Philae became the first spacecraft to softly land on a comet nucleus. Due to the double failure of the cold gas hold-down thruster and the anchoring harpoons that should have fixed Philae to the surface, it spent approximately two hours bouncing over the comet surface to finally come at rest one km away from its target site. Nevertheless it was operated during the 57h of its First Science Sequence. The FSS, performed with the two batteries, should have been followed by the Long Term Science Sequence but Philae was in a place not well illuminated and fell into hibernation. Yet, thanks to reducing distance to the Sun and to seasonal effect, it woke up at end of April and on 13th of June it contacted Rosetta again. To achieve this successful landing, an intense preparation work had been carried out mainly between August and November 2014 to select the targeted landing site and define the final landing trajectory. After the landing, the data collected during on-comet operations have been used to assess the final position and orientation of Philae, and to prepare the wake-up. This paper addresses the Flight Dynamics studies done in the scope of this landing preparation from Lander side, in close cooperation with the team at ESA, responsible for Rosetta, as well as for the reconstruction of the bouncing trajectory and orientation of the Lander after touchdown.

Skin ulcer development in cutaneous leishmaniasis due to Leishmania braziliensis infection is associated with a mononuclear cell infiltrate and high levels of tumor necrosis factor (TNF). Herein, we show that despite the absence of Leishmania-driven TNF, a cutaneous leishmaniasis patient with acquired immunodeficiency syndrome developed a skin ulcer. The presence of mononuclear phagocytes and high levels of TNF, chemokine (C-C motif) ligand 2 (CCL2), and metalloproteinase-9 in tissue are identified as potential contributors to immunopathology observed in L. braziliensis-infected patients.

ABSTRACT On December 18th, 2004, PARASOL was successfully put into orbit by a multiple Ariane 5 launch. PARASOL is a microsatellite of the CNES MYRIADE product line thereby sharing the same platform and on-board software which flew for the first time on the DEMETER mission, launched in June 2004 and still in orbit. The two MYRIADE microsatellites currently in flight have provided a substantial amount of information concerning the behaviour of their shared platform and, in particular, of their AOCS architecture. This article will present the AOCS results from PARASOL and how they confirm those obtained from DEMETER (Fallet, 2005). 1. PARASOL MISSION PARASOL is a 120 kg microsatellite intended to join the Aqua Train, an array of satellites following one another in the same orbit, led by Aqua (Fig. 2). The purpose of the PARASOL (Polarization and Anisotropy of Reflectance for Atmospheric Sciences coupled with Observations from a Lidar) mission is to measure polarized and multi-directional reflectances, on areas observed by the instruments of the other members of the Aqua Train (Bastien-Thiry, 2005). These measurements are taken by the instrument POLDER (POLarization and Directionality of Earth Reflectance), a wide field camera developed by CNES with 16 spectral and polarized filters.

The DEMETER satellite was launched June 29(th), 2004. This satellite is the first application of MYRIADE micro-satellite program conducted by CNES. MYRIADE main objective is to permit the access to space for scientific and technological missions in a short delay and with reduced cost. Based on the MYRIADE generic platform, DEMETER is a 3-axis stabilized, nadir-pointing satellite. It is controlled with reaction wheels and magnetotorquer bars and uses a star tracker for attitude determination. DEMETER suffered several problems after launch however since that time the satellite has been performing very well. This paper introduces DEMETER. It briefly describes the mission objectives and the satellite. It focuses on the AOCS architecture and performances to cope with the MYRIADE objectives and the DEMETER mission. After the description of the validation process, it presents the preliminary in-orbit behavior and performances.

Just as in electrical cornmunications, there are two basic methods for optical multiplexing, namely frequency and time division multiplexing. Frequency multiplexing in the optical range is cornmonly known as Wavelength Division Multiplexing (WDM) and it consists in launching severallasers of different wavelength into the same fiber, each of them modulated aeeording to a different electrical signal. On the other hand, Optieal Time Division Multiplexing (OTDM) combines several lasers of the same wavelength using a pulse modulation with Retum to Zero (RZ) for eaeh and introducing proper delays between the pulses to avoid time overlap, interleaving the pulses in a time slot.