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Skin is exposed to various environmental assaults and undergoes morphological changes immediately after birth. Proper localization and function of immune cells in the skin is crucial for protection and establishment of skin tissue homeostasis. Here we report the discovery of a developmentally programmed process that directs preferential localization of invariant natural killer T (iNKT) cells to the skin for early local homeostatic regulation. We show that iNKT cells are programmed predominantly with a CCR10+ skin-homing phenotype during thymic development in infant and young mice. Early skin localization of iNKT cells is critical for proper commensal bacterial colonization and tissue development. Mechanistically, skin iNKT cells provide a local source of transferrin that regulates iron metabolism in hair follicle progenitor cells and helps hair follicle development. These findings provide molecular insights into the establishment and physiological functions of iNKT cells in the skin during early life.
Assuntos
Células T Matadoras Naturais , Camundongos , Animais , Pele , Homeostase , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
Innate lymphoid cells (ILCs) 'preferentially' localize into barrier tissues, where they function in tissue protection but can also contribute to inflammatory diseases. The mechanisms that regulate the establishment of ILCs in barrier tissues are poorly understood. Here we found that under steady-state conditions, ILCs in skin-draining lymph nodes (sLNs) were continuously activated to acquire regulatory properties and high expression of the chemokine receptor CCR10 for localization into the skin. CCR10(+) ILCs promoted the homeostasis of skin-resident T cells and, reciprocally, their establishment in the skin required T cell-regulated homeostatic environments. CD207(+) dendritic cells expressing the transcription factor Foxn1 were required for the proper generation of CCR10(+) ILCs. These observations reveal mechanisms that underlie the specific programming and priming of skin-homing CCR10(+) ILCs in the sLNs.
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Homeostase/imunologia , Linfonodos/imunologia , Linfócitos/imunologia , Receptores CCR10/imunologia , Pele/imunologia , Transferência Adotiva , Animais , Citometria de Fluxo , Imunidade Inata/imunologia , Linfonodos/citologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
Surface modification could enhance the cell internalization efficiency of nanovehicles for targeted gene or drug delivery. However, the influence of surface modification parameters, including recognition manners, valences, and patterns, is often clouded, especially for the endocytosis of DNA nanostructures in customized shapes. Focusing on an icosahedral DNA framework, we systematically programmed three distinct types of ligands with diverse valence and spatial distribution on their outer surface to study the internalization efficiency, endocytic pathways, and postinternalization fate. The comparison in different aspects of parameters deepens our understanding of the intricate relationship between surface modification and cell entry behavior, offering insights crucial for designing and optimizing DNA framework nanostructures for potent cell-targeted purposes.
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DNA , Endocitose , Propriedades de Superfície , DNA/química , Humanos , Nanoestruturas/química , Ligantes , Células HeLaRESUMO
A nonlinear Tomlinson-Harashima precoding (NTHP) scheme has been verified for its capability to effectively address both the linear and nonlinear inter-symbol interferences (ISIs) arising in the intensity-modulation direct-detection (IM-DD) fiber optics transmission. Nevertheless, the application of the NTHP scheme may significantly increase the number of levels for the intensity modulated signals, resulting in the reduction of both eye width and receiver sensitivity. Here, we propose a fractionally spaced NTHP with a weight clustering (FS-NTHP-WC) scheme. Consequently, an accurate ISI feedback can be obtained to enlarge the eye width; meanwhile a hardware-efficient implementation without the equalization penalty can be achieved by weight clustering and pruning. When the C-band 100â Gbaud/λ PAM-4 signals are transmitted, our proposed FS-NTHP-WC scheme not only can achieve 0.25â dB and 0.5â dB gains of receiver sensitivity under back-to-back (B2B) and 2-km standard single-mode fiber (SSMF) transmission conditions, respectively, but can also cut down the computational complexity by 90% and 76% in terms of the number of multiplications and additions, respectively, in comparison with the NTHP scheme.
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To monitor the health of the fiber network and its ambient environment in densely populated access/metro network areas, in this Letter, an endogenous distributed acoustic sensing (DAS) has been proposed and achieved in a coherent digital subcarrier multiplexing (DSCM) system. Rather than specially allocating a sensing probe in general integrated communication and sensing schemes, the fractional Fourier transformed (FrFT) training sequence (TS) designated for time/frequency synchronization in DSCM coherent communications has been repurposed for sensing. While achieving excellent synchronization performance of communication, the FrFT-based TS can also be concurrently utilized to perform distributed vibration sensing. Experimental results demonstrate that the FrFT-based timing/frequency synchronization sequence is repurposed to achieve a DAS sensitivity of 70â p ε/Hz at a spatial resolution of 5â m, along with 100-Gb/s 16 quadrature amplitude modulation (QAM) DSCM transmission, without a loss of spectral efficiency.
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Phase evolution of soliton and that of first-order sidebands in a fiber laser are investigated by using nonlinear Fourier transform (NFT). Development from dip-type sidebands to peak-type (Kelly) sidebands is presented. The phase relationship between the soliton and the sidebands calculated by the NFT are in good agreement with the average soliton theory. Our results suggest that NFT can be an effective tool for the analysis of laser pulses.
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We investigate the polarization dynamics of vector solitons in a fiber laser mode-locked by a saturable absorber (SA). Three types of vector solitons were obtained in the laser, including group velocity locked vector solitons (GVLVS), polarization locked vector solitons (PLVS), and polarization rotation locked vector solitons (PRLVS). Their polarization evolution during intracavity propagation is discussed. Pure vector solitons are obtained from the continuous wave (CW) background by soliton distillation, and the characteristics of the vector solitons without and with distillation are analyzed, respectively. Numerical simulations suggest that the features of vector solitons in a fiber laser could be assemble to those generated in fibers.
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Enabling communication networks with sensing functionality has attracted significant interest lately. The digital subcarrier multiplexing (DSCM) technology is widely promoted in short-reach scenarios for its inherent flexibility of fine-tuning the spectrum. Its compatibility with large-scale as-deployed coherent architectures makes it particularly suited for cost-sensitive integrated sensing and communication applications. In this paper, we propose a scheme of spectrally integrating the digital linear frequency modulated sensing signal into DSCM signals to achieve simultaneous sensing and communication through shared transmitter. Consequently, this cost-effective scheme has been demonstrated to achieve 100-Gb/s dual-polarization quadrature phase-shift keying (DP-QPSK) and 200-Gb/s dual-polarization 16-ary quadrature amplitude modulation (DP-16QAM) transmission with a distributed acoustic sensing sensitivity of 69 pε/Hz and 88 pε/Hz respectively, at a spatial resolution of 4 m.
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Polarization properties of a soliton generated in a fiber laser of zero dispersion are investigated. Similar to the solitons generated in a fiber laser of all anomalous dispersion, the polarization ellipse of the soliton rotated during pulse evolution inside the cavity. The number of rotations relies on the cavity averaged birefringence with nonlinear bias. The larger the cavity averaged birefringence is, the bigger the bias is. When the period multiplying of solitons appears, the number of rotations depends on both multiplying periods and the cavity averaged birefringence. Multiple polarization states can be observed at a fixed position in the cavity depending on the multiplying period. When the cavity length is equal to n times of the averaged beat length, the polarization ellipse of the soliton rotates n∗m times at a fixed position, where m is equal to the multiplying period.
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The performance of high baud-rate intensity modulation direct detection (IM-DD) transmissions is severely degraded by both the linear and nonlinear inter-symbol interference (ISI). Here, we propose and experimentally demonstrate a transmitter-side look-up-table pre-distortion combined with nonlinear Tomlinson-Harashima pre-coding (LUT_PD-NTHP) scheme with the capability of mitigating the linear and nonlinear ISI simultaneously, enabling a C-band 200 Gbit/s/λ PAM-4 transmission over 2-km standard single mode fiber (SSMF), under an end-to-end 10-dB bandwidth of about 20 GHz. The proposed LUT_PD-NTHP scheme is experimentally verified to be superior to the LUT pre-distortion combined with linear THP (LUT_PD-LTHP) scheme, in terms of both the receiver sensitivity and the LUT storage requirement, when only the feed-forward equalization (FFE) is used at the receiver-side. In particular, after the 200 Gbit/s PAM-4 signal transmission over the 2-km SSMF without the chromatic dispersion (CD) compensation, the proposed LUT_PD-NTHP scheme with a LUT pattern length of 3 possesses not only 0.25 dB improvement of the receiver sensitivity but also about 99% LUT pattern reduction, in comparison with the LUT_PD-LTHP scheme with a LUT pattern length of 5.
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Nonlinear Fourier transform (NFT) is a powerful tool for characterizing optical soliton dynamics, which, however, suffers from fundamental limitations that ultra-wide bandwidth photodetectors and ultra-high sampling rate analog-to-digital converters should be used when accessing the full-field information of an ultrafast optical pulse. Herein, we report on the experimental demonstration of the linear optical sampling (LOS) enabled nonlinear frequency spectrum classification of ultrashort optical pulses, which could break this limitation. Instead of traditional coherent detection, the LOS overcomes the ultra-wide bandwidth constraint of commercially available optoelectrical devices. By finely adjusting the repetition rate difference between the soliton to be characterized and the sampling pulsed source, a 55.56-TSa/s equivalent sampling rate arising in the LOS can be secured, where only 400-MHz balanced photodetectors and 5-GSa/s analog-to-digital converter are used. Meanwhile, according to the nonlinear frequency spectrum calculated from the accurate full-field information, the promising concept of soliton distillation has been experimentally verified for the first time. The LOS-enabled NFT technique provides an alternative and efficient characterization tool for ultrafast fiber lasers, which facilities comprehensive insight into soliton dynamics.
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Transition from a gain-guided soliton (GGS) to a fully developed noise-like pulse (NLP) is numerically demonstrated in fiber lasers operated in the normal dispersion regime, which explains well the experimental observation of spectrum evolution that the bottom of the averaged spectrum gradually broadens with pump power increasing. Numerical results suggest that the transition could also happen under the condition of cavity linear phase delay bias change with fixed pump power. It is demonstrated that the peak power clamping effect and the normal dispersion are the key factors leading to the spectrum evolution. In addition, intermittent meta-stable states between GGS and NLP can be obtained when the cavity dispersion is chosen at small normal dispersion.
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Using numerical simulation, we have investigated the generation of color solitons consisting of two radiation fragments with different carrier frequencies in a dual-wavelength laser. The proposed mechanism for the formation of such solitons involves nonlinear losses that increase with increasing intensity, the dispersion of the refractive index, spectral gain inhomogeneity, and the generation of a doublet radiation spectrum, owing to the corresponding spectral-dependent losses in the laser. The proposed theory explains the main features of the experimentally observed formation of color domains in fiber lasers and has the potential for further development of methods for controlling the nonlinear dynamics of laser radiation.
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In this study, we conduct a numerical evaluation of the impact of the recovery time of a saturable absorber (SA) on the output performance of an Yb-doped fiber laser operating in the dissipative soliton regime. Particularly, we evaluate the output pulse characteristics, such as the pulse width, spectral bandwidth, pulse peak power, and pulse energy depending on the change in recovery time. Applying a too-slow SA recovery time above a certain critical value is shown to make the output pulse unstable and broken. Furthermore, we demonstrate that there is an optimum recovery time range for stable dissipative soliton pulse generation, depending on the cavity dispersion and modulation depth of the SA. Further, we perform an additional numerical simulation of the pulse compression to demonstrate the relationship between the output dechirped pulse width and SA recovery time. The optimum approach for the generation of the shortest dechirped pulses in the dissipative soliton regime will be to construct a fiber laser cavity with a small normal cavity group velocity dispersion and use an SA with an appropriate recovery time.
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Period doubling (PD) and the merging of multiple dissipative-soliton-resonance (DSR) pulses are investigated in a fiber laser. Depending on the initial conditions and operation settings, various PDs of multiple DSR pulses are achieved. For two coexisting DSR pulses, we observe PD on both pulses or PD on a single pulse while the other pulse maintains period one. For three coexisting DSR pulses, PD on all pulses or PD on one/two pulse(s) are achieved when the other pulses maintain period one. It is observed that excessively increasing the pump power could destroy the PD behavior. Within certain parameters, PD behavior can be maintained by increasing the pump power. Apart from the appearance of PD, it is found that two DSR pulses may merge into a single DSR pulse if the pulse interval is small enough during pump power increase.
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Highly sensitive ethanol sensors are important for environmental and industrial monitoring. In our work, we demonstrate a method to enhance the response of a Schottky sensor based on a ZnO nano/microwire (NMW) by triboelectric nanogenerator (TENG). Via lowering the Schottky barrier height (SBH) via the high voltage from TENG, the response of the sensor is enhanced by 139% for 100 ppm ethanol. This method accelerates the recovery process. The high voltage from TENG produces a high intensity electric field to drive diffusion of the oxygen vacancies in ZnO NMW toward to the junction area around the interface. It is equivalent to applying the reverse voltage on the Schottky junction, which leads to the increase of depletion width. More chemisorbed oxygen on the depletion region is consumed once the ethanol gas is injected into the chamber, which improves the response of the ethanol sensor. This study provides a new, simple, and effective method to improve the sensor response.
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Due to the weak birefringence of single mode fibers, solitons generated in fiber lasers are indeed vector pulses and exhibit periodic parameter change including polarization evolution even when there is a polarizer inside the cavity. Period doubling eigenstates of solitons generated in a fiber laser mode-locked by the nonlinear polarization rotation, i.e., period doubling of polarization components of the soliton, are numerically explored in detail. We found that, apart from the synchronous evolution between the two polarization components, there exists asynchronous development depending on the detailed operation conditions. In addition, period doubling of one polarization component together with period-one of another polarization component can be achieved. When the period tripling window is obtained, much complexed dynamics on the two polarization components could be observed.
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We investigate various patterns of vector solitons arising in a passively mode-locked fiber laser based on semiconductor saturable absorber mirror (SESAM). By properly adjusting the cavity parameters including the pump power and intra-cavity birefringence, the fundamental vector solitons, vector soliton molecules, and macroscopic vector solitons can be separately observed. In particular, both vector soliton molecule and macroscopic vector solitons exhibit multi-pulse structure along one polarization axis while there occurs single pulse profile at its orthogonal polarization component. Thus, they can be treated as "1 + 2" and "1+n" vector solitons. Moreover, the size of the macroscopic solitons can be manipulated from half of the cavity to even the whole cavity. The generation mechanisms of these vector soliton patterns are also investigated.
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Recent progress in real-time spectral interferometry enables access to the internal dynamics of optical multisoliton complexes. Here, we report on the first, to the best of our knowledge, experimental observation of shaking soliton molecules by means of the dispersive Fourier transform technique. Beyond the simplex vibrating soliton pairs, multiple oscillatory motions can jointly involve in the internal dynamics, reminiscent of the shaking soliton pairs. Both quasi-periodically and chaotically evolving phase oscillations are approached in the sense of different oscillatory frequencies. In addition, the shaking soliton pair combined with sliding phase dynamics is also observed, and is interpreted as the superposition of two different internal motions. All of these results shed new light on the internal dynamics of soliton molecules with higher degrees of freedom, as well as enrich the framework toward multisoliton complexes.
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Weak polarization dependence exists in most fiber components. We numerically demonstrated passive mode locking in fiber lasers based on weak polarization dependence down to polarization-dependent loss of 1.76 dB. Different polarization dependences are investigated to unveil its role for achieving passive mode locking. The anomalous dispersion region and the normal dispersion regime are both tested. It is found that, independent of operating dispersion regime, stronger gain is required for achieving mode locking with lower polarization dependence. Our numerical demonstration confirms previous experimental results and broadens the knowledge on additive-pulse mode locking.