Synchronization of two chaotic microresonator frequency combs.

We explore the synchronization of chaotic microresonator frequency combs, emphasizing the modulation instability state, which is known for its inherent chaotic behaviors. Our study confirms that the synchronization of two such combs is feasible by injecting the output from the lead microresonator into the next microresonator's input. We also identify the optimal parameters for this synchronization. Remarkably, even partial injection from the leader is sufficient for synchronization, paving the way for versatile future system configurations. Such systems could simultaneously utilize distinct spectral components for synchronization and transmission. This work advances our understanding of chaotic microresonator combs, showing them to be pivotal elements in next-generation optical communication systems.

Neutrophil-to-lymphocyte ratio and lymphocyte count as an alternative to body mass index for screening malnutrition in older adults living in the community.

PURPOSE: Accurate height and weight measurement can be challenging in older adults and complicates nutritional status assessment. Other parameters like the neutrophil-to-lymphocyte ratio (NLR) and the lymphocyte count (LC) could be an option to these measurements. We aimed to test these variables as subrogates of body mass index (BMI) or calf-circumference (CC) for malnutrition screening in community-dwelling older adults. METHODS: This is a secondary analysis from the Salud, Bienestar y Envejecimiento (SABE) survey from Ecuador (2009). Includes data on demographics, health-related factors, physical assessments, and complete blood count, allowing to calculate NLR and LC to be used as part of the Mini Nutritional Assessment (MNA), instead of the BMI. Consequently, 4 models were included: standard MNA, MNA-CC, MNA-NLR and MNA-LC. Finally, age, sex, and comorbidities were considered as confounding variables. RESULTS: In our analysis of 1,663 subjects, 50.81% were women. Positive correlations with standard MNA were found for MNA-NLR (Estimate = 0.654, p < 0.001) MNA-CC (Estimate = 0.875, p value < 0.001) and MNA-LC (Estimate = 0.679, p < 0.001). Bland-Altman plots showed the smallest bias in MNA-CC. Linear association models revealed varying associations between MNA variants and different parameters, being MNA-NLR strongly associated with all of them (e.g. Estimate = 0.014, p = 0.001 for albumin), except BMI. CONCLUSION: The newly proposed model classified a greater number of subjects at risk of malnutrition and fewer with normal nutrition compared to the standard MNA. Additionally, it demonstrated a strong correlation and concordance with the standard MNA. This suggests that hematological parameters may offer an accurate alternative and important insights into malnutrition.

Ultrafast all-optical phase switching enabled by epsilon-near-zero materials in silicon.

Transparent conducting oxides (TCOs) have emerged as both particularly appealing epsilon-near-zero (ENZ) materials and remarkable candidates for the design and fabrication of active silicon nanophotonic devices. However, the leverage of TCO's ultrafast nonlinearities requires precise control of the intricate physical mechanisms that take place upon excitation. Here we investigate such behavior for ultrafast all-optical phase switching in hybrid TCO-silicon waveguides through numerical simulation. The model is driven from the framework of intraband-transition-induced optical nonlinearity. Transient evolution is studied with a phenomenological two-temperature model. Our results reveal the best compromise between energy consumption, insertion losses and phase change per unit length for enabling ultrafast switching times below 100 fs and compact active lengths in the order of several micrometers.

Design and On-Field Validation of an Embedded System for Monitoring Second-Life Electric Vehicle Lithium-Ion Batteries.

In the last few years, the growing demand for electric vehicles (EVs) in the transportation sector has contributed to the increased use of electric rechargeable batteries. At present, lithium-ion (Li-ion) batteries are the most commonly used in electric vehicles. Although once their storage capacity has dropped to below 80-70% it is no longer possible to use these batteries in EVs, it is feasible to use them in second-life applications as stationary energy storage systems. The purpose of this study is to present an embedded system that allows a Nissan® LEAF Li-ion battery to communicate with an Ingecon® Sun Storage 1Play inverter, for control and monitoring purposes. The prototype was developed using an Arduino® microcontroller and a graphical user interface (GUI) on LabVIEW®. The experimental tests have allowed us to determine the feasibility of using Li-ion battery packs (BPs) coming from the automotive sector with an inverter with no need for a prior disassembly and rebuilding process. Furthermore, this research presents a programming and hardware methodology for the development of the embedded systems focused on second-life electric vehicle Li-ion batteries. One second-life battery pack coming from a Nissan® Leaf and aged under real driving conditions was integrated into a residential microgrid serving as an energy storage system (ESS).

Large Pockels effect in micro- and nanostructured barium titanate integrated on silicon.

The electro-optical Pockels effect is an essential nonlinear effect used in many applications. The ultrafast modulation of the refractive index is, for example, crucial to optical modulators in photonic circuits. Silicon has emerged as a platform for integrating such compact circuits, but a strong Pockels effect is not available on silicon platforms. Here, we demonstrate a large electro-optical response in silicon photonic devices using barium titanate. We verify the Pockels effect to be the physical origin of the response, with r42 = 923 pm V-1, by confirming key signatures of the Pockels effect in ferroelectrics: the electro-optic response exhibits a crystalline anisotropy, remains strong at high frequencies, and shows hysteresis on changing the electric field. We prove that the Pockels effect remains strong even in nanoscale devices, and show as a practical example data modulation up to 50 Gbit s-1. We foresee that our work will enable novel device concepts with an application area largely extending beyond communication technologies.

Ultra-low loss hybrid ITO/Si thermo-optic phase shifter with optimized power consumption.

Typically, materials with large optical losses such as metals are used as microheaters for silicon based thermo-optic phase shifters. Consequently, the heater must be placed far from the waveguide, which could come at the expense of the phase shifter performance. Reducing the gap between the waveguide and the heater allows reducing the power consumption or increasing the switching speed. In this work, we propose an ultra-low loss microheater for thermo-optic tuning by using a CMOS-compatible transparent conducting oxide such as indium tin oxide (ITO) with the aim of drastically reducing the gap. Using finite element method simulations, ITO and Ti based heaters are compared for different cladding configurations and TE and TM polarizations. Furthermore, the proposed ITO based microheaters have also been fabricated using the optimum gap and cladding configuration. Experimental results show power consumption to achieve a π phase shift of 10 mW and switching time of a few microseconds for a 50 µm long ITO heater. The obtained results demonstrate the potential of using ITO as an ultra-low loss microheater for high performance silicon thermo-optic tuning and open an alternative way for enabling the large-scale integration of phase shifters required in emerging integrated photonic applications.

Ultra-compact non-volatile Mach-Zehnder switch enabled by a high-mobility transparent conducting oxide.

Compact and broadband non-volatile silicon devices are mainly absorption based. Hence, access to low-loss non-volatile phase shifters is still a challenge. Here, this problem is addressed by using a high-mobility transparent conducting oxide such as cadmium oxide as a floating gate in a flash-like structure. This structure is integrated in a Mach-Zehnder interferometer switch. Results show an active length of only 30 µm to achieve a $ \pi $π phase shift. Furthermore, an extinction ratio of 20 dB and insertion loss as low as 1 dB may be attained. The device shows an optical broadband response and can be controlled with low-power pulses in the nanosecond range. These results open a new, to the best of our knowledge, way for enabling compact silicon-based phase shifters with non-volatile performance.

Enhancing Pockels effect in strained silicon waveguides.

The magnitude and origin of the electro-optic measurements in strained silicon devices has been lately the object of a great controversy. Furthermore, recent works underline the importance of the masking effect of free carriers in strained waveguides and the low interaction between the mode and the highly strained areas. In the present work, the use of a p-i-n junction and an asymmetric cladding is proposed to eliminate the unwanted carrier influence and improve the electro-optical modulation response. The proposed configuration enhances the effective refractive index due to the strain-induced Pockels effect in more than two orders of magnitude with respect to the usual configuration.

Alignment tolerant, low voltage, 0.23†V.cm, push-pull silicon photonic switches based on a vertical pn junction.

In this paper, we present the design, fabrication and characterization of a carrier depletion silicon-photonic switch based on a highly doped vertical pn junction. The vertical nature of the pn junction enables the device to exhibit a modulation efficiency as high as 0.23 V.cm. Fast switching times of 60ps are achieved in a lumped configuration. Moreover, the process flow is highly tolerant to fabrication deviations allowing a seamless transfer to the 350 nm process node of a commercial complementary-metal-oxide semiconductor (CMOS) foundry. Overall, this work showcases the possibility of fabricating highly efficient carrier depletion-based silicon photonic switches using medium resolution lithography.

Non-volatile epsilon-near-zero readout memory.

The lack of memory effect of silicon makes it unfeasible to store electronic data in photonics. Here we propose a non-volatile readout photonic memory, which is electronically written/erased and optically read. The memory utilizes indium tin oxide as a floating gate and exploits its epsilon-near-zero regime and electro-optic activity. Extinction ratios greater than 10 dB in a bandwidth of 100 nm for a 5 µm long memory are obtained. Furthermore, power consumption in the order of microwatts with retention times of about a decade have been predicted. The proposed structure opens a pathway for developing highly integrated electro-optic devices such as memory banks.

Characterization of proliferative, glial and angiogenic responses after a CoCl2 -induced injury of photoreceptor cells in the adult zebrafish retina.

The adult zebrafish is considered a useful model for studying mechanisms involved in tissue growth and regeneration. We have characterized cytotoxic damage to the retina of adult zebrafish caused by the injection of cobalt chloride (CoCl2 ) into the vitreous cavity. The CoCl2 concentration we used primarily caused injury to photoreceptors. We observed the complete disappearance of cones, followed by rods, across the retina surface from 28 to 96 hr after CoCl2 injury. The loss of 30% of bipolar cells was also observed by 50 hr after lesion (hpl). CoCl2 injury provoked a strong induction of the proliferative activity of multipotent Müller glia and derived progenitors. The effect of CoCl2 on retina cells was significantly reduced by treatment with glutamate ionotropic receptor antagonists. Cone photoreceptor regeneration occurred 25 days after injury. Moreover, a single dose of CoCl2 induced vascular damage and regeneration, whereas three injections of CoCl2 administered weekly provoked neovascular-like changes 20 days after injury. CoCl2 injury also caused microglial reactivity in the optic disc, retina periphery and fibre layer. CoCl2 -induced damage enhanced pluripotency and proneural transcription factor gene expression in the mature retina 72 hpl. Tumour necrosis factor alpha, vascular endothelial growth factor (VEGF) and VEGF receptor mRNA levels were also significantly enhanced by 72 hpl. The injury paradigm we have described in this work may be useful for the discovery of signalling molecules and pathways that participate in the regenerative response and it may serve as a model to screen for compounds that could potentially treat aberrant angiogenesis.

Optical switching in hybrid VO2/Si waveguides thermally triggered by lateral microheaters.

The performance of optical devices relying in vanadium dioxide (VO2) technology compatible with the silicon platform depends on the polarization of light and VO2 properties. In this work, optical switching in hybrid VO2/Si waveguides thermally triggered by lateral microheaters is achieved with insertion losses below 1 dB and extinction ratios above 20 dB in a broad bandwidth larger than 30 nm. The optical switching response has been optimized for TE and TM polarizations by using a homogeneous and a granular VO2 layer, respectively, with a small impact on the electrical power consumption. The stability and reversibility between switching states showing the possibility of bistable performance is also demonstrated.

Experimental demonstration of a tunable transverse electric pass polarizer based on hybrid VO2/silicon technology.

A tunable transverse electric (TE) pass polarizer is demonstrated based on hybrid vanadium dioxide/silicon (VO2/Si) technology. The 20-µm-long TE pass polarizer exploits the phase transition of the active VO2 material to control the rejection of the unwanted transverse magnetic (TM) polarization. The device features insertion losses below 1 dB at static conditions and insertion losses of 5.5 dB and an attenuation of TM polarization of 19 dB in the active state for a wavelength range between 1540 nm and 1570 nm. To the best of our knowledge, this is the first time that tunable polarizers compatible with Si photonics are demonstrated.

High performace silicon 2x2 optical switch based on a thermo-optically tunable multimode interference coupler and efficient electrodes.

Optical switches based on tunable multimode interference (MMI) couplers can simultaneously reduce the footprint and increase the tolerance against fabrication deviations. Here, a compact 2x2 silicon switch based on a thermo-optically tunable MMI structure with a footprint of only 0.005 mm(2) is proposed and demonstrated. The MMI structure has been optimized using a silica trench acting as a thermal isolator without introducing any substantial loss penalty or crosstalk degradation. Furthermore, the electrodes performance have significantly been improved via engineering the heater geometry and using two metallization steps. Thereby, a drastic power consumption reduction of around 90% has been demonstrated yielding to values as low as 24.9 mW. Furthermore, very fast switching times of only 1.19 µs have also been achieved.

Compact and low-loss asymmetrical multimode interference splitter for power monitoring applications.

This Letter presents a compact and low-loss 1×2 asymmetrical multimode interference (A-MMI) splitter in rib geometry for on-chip power monitoring at 1.55 µm, where a given alteration of the component cavity determines arbitrary values of the output power splitting ratios. The device shows reduced losses (∼0.4-0.8 dB) and robustness across a 40 nm optical bandwidth (1540-1580 nm).

Influence of BaTiO3 ferroelectric orientation for electro-optic modulation on silicon.

The influence of BaTiO(3) ferroelectric domain orientations for high efficiency electro-optic modulation has been thoroughly analyzed. The Mach-Zehnder modulator structure is based on a CMOS compatible silicon/BaTiO(3)/silicon slot waveguide that supports both TE and TM polarizations whereas the Pockels effect is exploited by the application of a horizontal electric field with lateral electrodes placed on top of the BaTiO(3) layer. The influence of the waveguide parameters has been optimized for each configuration and the lowest V(π) voltage combined with low losses has been determined. A V(π)L as low as 0.27 V·cm has been obtained for a-axis oriented BaTiO(3) and TE polarization by rotating the waveguide structure to an optimum angle.

Assessing Neutrophil-to-Lymphocyte Ratio as a Nutritional Indicator in Community-Dwelling Older Adults.

BACKGROUND: In an aging population, there is an increasing need for easily accessible nutritional markers. AIMS: To determine whether the neutrophil-to-lymphocyte ratio (NLR) can serve as an effective nutritional indicator compared to the Mini-Nutritional Assessment Short Form (MNA-SF) or other common markers such as albumin and body mass index (BMI). METHODS: Data were obtained from the SABE study in Ecuador, which included participants aged 60 years or older. This cross-sectional study collected comprehensive data, including demographics, health-related factors, and physical assessments. Neutrophil and lymphocyte counts were measured by complete blood count. Nutritional status was assessed by MNA-SF, and BMI was calculated. Several physical tests were performed to evaluate the participants' functional status. Confounding variables such as age, sex, and comorbidities were considered. RESULTS: The final sample consisted of 1790 subjects (48.9% male). The overall median age was 68 years (IQR 64,76). BMI and lymphocytes were higher in females, while NLR was higher in males. MNA-SF showed a negative association with NLR. Similarly, lymphocyte count shows a positive association with MNA-SF. Physical tests, such as the Romberg test and the Five Times Sit-to-Stand test, also showed correlations with NLR and lymphocyte count, respectively. CONCLUSION: The study results suggest a significant relationship between NLR and lymphocytes, and nutritional status. The correlation with albumin is stronger with NLR than with BMI. The simplicity and affordability of NLR may make it suitable for routine use in several medical fields, improving our understanding of the complex relationship between nutrition, inflammation, and overall health.

Impact of GST thickness on GST-loaded silicon waveguides for optimal optical switching.

Phase-change integrated photonics has emerged as a new platform for developing photonic integrated circuits by integrating phase-change materials like GeSbTe (GST) onto the silicon photonics platform. The thickness of the GST patch that is usually placed on top of the waveguide is crucial for ensuring high optical performance. In this work, we investigate the impact of the GST thickness in terms of optical performance through numerical simulation and experiment. We show that higher-order modes can be excited in a GST-loaded silicon waveguide with relatively thin GST thicknesses (<100 nm), resulting in a dramatic reduction in the extinction ratio. Our results would be useful for designing high-performance GST/Si-based photonic devices such as non-volatile memories that could find utility in many emerging applications.

Bone Progenitors Pull the Strings on the Early Metabolic Rewiring Occurring in Prostate Cancer Cells.

Metastatic prostate cancer (PCa) cells soiling in the bone require a metabolic adaptation. Here, we identified the metabolic genes fueling the seeding of PCa in the bone niche. Using a transwell co-culture system of PCa (PC3) and bone progenitor cells (MC3T3 or Raw264.7), we assessed the transcriptome of PC3 cells modulated by soluble factors released from bone precursors. In a Principal Component Analysis using transcriptomic data from human PCa samples (GSE74685), the altered metabolic genes found in vitro were able to stratify PCa patients in two defined groups: primary PCa and bone metastasis, confirmed by an unsupervised clustering analysis. Thus, the early transcriptional metabolic profile triggered in the in vitro model has a clinical correlate in human bone metastatic samples. Further, the expression levels of five metabolic genes (VDR, PPARA, SLC16A1, GPX1 and PAPSS2) were independent risk-predictors of death in the SU2C-PCF dataset and a risk score model built using this lipid-associated signature was able to discriminate a subgroup of bone metastatic PCa patients with a 23-fold higher risk of death. This signature was validated in a PDX pre-clinical model when comparing MDA-PCa-183 growing intrafemorally vs. subcutaneously, and appears to be under the regulatory control of the Protein Kinase A (PKA) signaling pathway. Secretome analyses of conditioned media showcased fibronectin and type-1 collagen as critical bone-secreted factors that could regulate tumoral PKA. Overall, we identified a novel lipid gene signature, driving PCa aggressive metastatic disease pointing to PKA as a potential hub to halt progression.

A Journey into the Clinical Relevance of Heme Oxygenase 1 for Human Inflammatory Disease and Viral Clearance: Why Does It Matter on the COVID-19 Scene?

Heme oxygenase 1 (HO-1), the rate-limiting enzyme in heme degradation, is involved in the maintenance of cellular homeostasis, exerting a cytoprotective role by its antioxidative and anti-inflammatory functions. HO-1 and its end products, biliverdin, carbon monoxide and free iron (Fe2+), confer cytoprotection against inflammatory and oxidative injury. Additionally, HO-1 exerts antiviral properties against a diverse range of viral infections by interfering with replication or activating the interferon (IFN) pathway. Severe cases of coronavirus disease 2019 (COVID-19), an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are characterized by systemic hyperinflammation, which, in some cases, leads to severe or fatal symptoms as a consequence of respiratory failure, lung and heart damage, kidney failure, and nervous system complications. This review summarizes the current research on the protective role of HO-1 in inflammatory diseases and against a wide range of viral infections, positioning HO-1 as an attractive target to ameliorate clinical manifestations during COVID-19.