Highly multiplexed bioactivity screening reveals human and microbiota metabolome-GPCRome interactions.

The human body contains thousands of metabolites derived from mammalian cells, the microbiota, food, and medical drugs. Many bioactive metabolites act through the engagement of G-protein-coupled receptors (GPCRs); however, technological limitations constrain current explorations of metabolite-GPCR interactions. Here, we developed a highly multiplexed screening technology called PRESTO-Salsa that enables simultaneous assessment of nearly all conventional GPCRs (>300 receptors) in a single well of a 96-well plate. Using PRESTO-Salsa, we screened 1,041 human-associated metabolites against the GPCRome and uncovered previously unreported endogenous, exogenous, and microbial GPCR agonists. Next, we leveraged PRESTO-Salsa to generate an atlas of microbiome-GPCR interactions across 435 human microbiome strains from multiple body sites, revealing conserved patterns of cross-tissue GPCR engagement and activation of CD97/ADGRE5 by the Porphyromonas gingivalis protease gingipain K. These studies thus establish a highly multiplexed bioactivity screening technology and expose a diverse landscape of human, diet, drug, and microbiota metabolome-GPCRome interactions.

A Forward Chemical Genetic Screen Reveals Gut Microbiota Metabolites That Modulate Host Physiology.

The intestinal microbiota produces tens of thousands of metabolites. Here, we used host sensing of small molecules by G-protein coupled receptors (GPCRs) as a lens to illuminate bioactive microbial metabolites that impact host physiology. We screened 144 human gut bacteria against the non-olfactory GPCRome and identified dozens of bacteria that activated both well-characterized and orphan GPCRs, including strains that converted dietary histidine into histamine and shaped colonic motility; a prolific producer of the essential amino acid L-Phe, which we identified as an agonist for GPR56 and GPR97; and a species that converted L-Phe into the potent psychoactive trace amine phenethylamine, which crosses the blood-brain barrier and triggers lethal phenethylamine poisoning after monoamine oxidase inhibitor administration. These studies establish an orthogonal approach for parsing the microbiota metabolome and uncover multiple biologically relevant host-microbiota metabolome interactions.

Within-host evolution of a gut pathobiont facilitates liver translocation.

Gut commensal bacteria with the ability to translocate across the intestinal barrier can drive the development of diverse immune-mediated diseases1-4. However, the key factors that dictate bacterial translocation remain unclear. Recent studies have revealed that gut microbiota strains can adapt and evolve throughout the lifetime of the host5-9, raising the possibility that changes in individual commensal bacteria themselves over time may affect their propensity to elicit inflammatory disease. Here we show that within-host evolution of the model gut pathobiont Enterococcus gallinarum facilitates bacterial translocation and initiation of inflammation. Using a combination of in vivo experimental evolution and comparative genomics, we found that E. gallinarum diverges into independent lineages adapted to colonize either luminal or mucosal niches in the gut. Compared with ancestral and luminal E. gallinarum, mucosally adapted strains evade detection and clearance by the immune system, exhibit increased translocation to and survival within the mesenteric lymph nodes and liver, and induce increased intestinal and hepatic inflammation. Mechanistically, these changes in bacterial behaviour are associated with non-synonymous mutations or insertion-deletions in defined regulatory genes in E. gallinarum, altered microbial gene expression programs and remodelled cell wall structures. Lactobacillus reuteri also exhibited broadly similar patterns of divergent evolution and enhanced immune evasion in a monocolonization-based model of within-host evolution. Overall, these studies define within-host evolution as a critical regulator of commensal pathogenicity that provides a unique source of stochasticity in the development and progression of microbiota-driven disease.

DNMT3a-mediated methylation of PPARγ promote intervertebral disc degeneration by regulating the NF-κB pathway.

Intervertebral disc degeneration (IVDD) is a common chronic musculoskeletal disease that causes chronic low back pain and imposes an immense financial strain on patients. The pathological mechanisms underlying IVDD have not been fully elucidated. The development of IVDD is closely associated with abnormal epigenetic changes, suggesting that IVDD progression may be controlled by epigenetic mechanisms. Consequently, this study aimed to investigate the role of epigenetic regulation, including DNA methyltransferase 3a (DNMT3a)-mediated methylation and peroxisome proliferator-activated receptor γ (PPARγ) inhibition, in IVDD development. The expression of DNMT3a and PPARγ in early and late IVDD of nucleus pulposus (NP) tissues was detected using immunohistochemistry and western blotting analyses. Cellularly, DNMT3a inhibition significantly inhibited IL-1ß-induced apoptosis and extracellular matrix (ECM) degradation in rat NP cells. Pretreatment with T0070907, a specific inhibitor of PPARγ, significantly reversed the anti-apoptotic and ECM degradation effects of DNMT3a inhibition. Mechanistically, DNMT3a modified PPARγ promoter hypermethylation to activate the nuclear factor-κB (NF-κB) pathway. DNMT3a inhibition alleviated IVDD progression. Conclusively, the results of this study show that DNMT3a activates the NF-κB pathway by modifying PPARγ promoter hypermethylation to promote apoptosis and ECM degradation. Therefore, we believe that the ability of DNMT3a to mediate the PPARγ/NF-κB axis may provide new ideas for the potential pathogenesis of IVDD and may become an attractive target for the treatment of IVDD.

The Xenorhabdus nematophila LrhA transcriptional regulator modulates production of γ-keto-N-acyl amides with inhibitory activity against mutualistic host nematode egg hatching.

Xenorhabdus nematophila is a symbiotic Gammaproteobacterium that produces diverse natural products that facilitate mutualistic and pathogenic interactions in their nematode and insect hosts, respectively. The interplay between X. nematophila secondary metabolism and symbiosis stage is tuned by various global regulators. An example of such a regulator is the LysR-type protein transcription factor LrhA, which regulates amino acid metabolism and is necessary for virulence in insects and normal nematode progeny production. Here, we utilized comparative metabolomics and molecular networking to identify small molecule factors regulated by LrhA and characterized a rare γ-ketoacid (GKA) and two new N-acyl amides, GKA-Arg (1) and GKA-Pro (2) which harbor a γ-keto acyl appendage. A lrhA null mutant produced elevated levels of compound 1 and reduced levels of compound 2 relative to wild type. N-acyl amides 1 and 2 were shown to be selective agonists for the human G-protein-coupled receptors (GPCRs) C3AR1 and CHRM2, respectively. The CHRM2 agonist 2 deleteriously affected the hatch rate and length of Steinernema nematodes. This work further highlights the utility of exploiting regulators of host-bacteria interactions for the identification of the bioactive small molecule signals that they control. IMPORTANCE: Xenorhabdus bacteria are of interest due to their symbiotic relationship with Steinernema nematodes and their ability to produce a variety of natural bioactive compounds. Despite their importance, the regulatory hierarchy connecting specific natural products and their regulators is poorly understood. In this study, comparative metabolomic profiling was utilized to identify the secondary metabolites modulated by the X. nematophila global regulator LrhA. This analysis led to the discovery of three metabolites, including an N-acyl amide that inhibited the egg hatching rate and length of Steinernema carpocapsae nematodes. These findings support the notion that X. nematophila LrhA influences the symbiosis between X. nematophila and S. carpocapsae through N-acyl amide signaling. A deeper understanding of the regulatory hierarchy of these natural products could contribute to a better comprehension of the symbiotic relationship between X. nematophila and S. carpocapsae.

Excimer laser coronary angioplasty combined with drug-coated balloon in the treatment of in-stent restenosis.

OBJECTIVES: The aim of this study is to investigate the safety and efficacy of excimer laser coronary angioplasty (ELCA) combined with drug-coated balloons (DCBs) in the treatment of in-stent restenosis (ISR), and to explore whether the contrast injection technique would improve the neointimal tissue ablation of ELCA. METHODS: We studied patients diagnosed with ISR between January 2019 and October 2022 at two medical centers. These patients underwent DCB angioplasty guided by optical coherence tomography (OCT). Based on whether ELCA was performed before DCB treatment, patients were categorized into two groups: the ELCA + DCB group and the DCB group. All patients underwent clinical follow-up 1 year after the procedure. The primary endpoint was the 1-year rate of target lesion revascularization (TLR), which was defined as any repeat percutaneous intervention or bypass surgery on the target vessel conducted to address restenosis or other complications related to the target lesion. The secondary endpoints including immediate luminal gain (ΔMLA, defined as the difference in minimum lumen area before and after the intervention). RESULTS: A total of 85 lesions in 75 patients were included. The mean age of the study population was 64.2 ± 12.0 years, with 81.3% male. Baseline clinical characteristics were well-balanced, and procedural success was 100% in both groups. The ELCA + DCB group (n = 24) exhibited a greater ΔMLA compared to the DCB group (n = 61) (3.57 ± 0.79 mm² vs. 2.50 ± 1.06 mm², [95% confidence interval, CI: 0.57-1.69], p < 0.001), The reduction in 1-year TLR was more frequently observed in patients from the ELCA + DCB group compared to the DCB group (hazard ratio 0.33 [95% CI: 0.11-0.99]; log-rank p = 0.048). The exploratory analysis showed that ELCA with contrast infusion is associated with greater acute lumen gain compared to ELCA with saline infusion (p < 0.001). CONCLUSIONS: The combination of ELCA and DCB is a safe and effective treatment strategy for in-stent stenosis. Additionally, compared with saline injection, ELCA with contrast injection is associated with greater acute lumen gain. However, the optimal contrast agent concentration and long-term outcome of the contrast injection technique need confirmation through larger sample sizes and prospective studies.

Generation of spatiotemporal vortices in nonlinear photonic crystals.

Spatiotemporal vortices (STOVs) are a new, to the best of our knowledge, type of structured light in which the optical phase circulates in space-time. In this work, we propose to generate STOVs via second harmonic generation in lithium niobate nonlinear photonic crystals (NPCs) with a linearly chirped Gaussian pulse as the fundamental wave. The structural function of the NPC is derived by the inverse design method. Numerical simulations of the intensity and phase profiles of the generated second harmonic waves are performed with both the amplitude-phase-modulated and the simplified binary-phase-modulated NPCs. We anticipate our study will be valuable for the experimental generation and manipulation of STOVs in NPCs.

Periostin promotes nucleus pulposus cells apoptosis by activating the Wnt/ß-catenin signaling pathway.

Intervertebral disc (IVD) degeneration (IVDD) is closely linked to degenerative spinal disease, resulting in disability, poor quality of life, and financial burden. Apoptosis of nucleus pulposus (NP) cells (NPCs) is a key pathological basis of IVDD. Periostin (POSTN), an extracellular matrix protein, is expressed in many tissues, whereas its abnormal expression is associated with IVDD. The conventional Wnt/ß-catenin pathway is also involved in IVDD and contributes to NPCs apoptosis. However, research on the mechanisms of POSTN in IVDD is lacking. This study investigated the relationship between POSTN and ß-catenin expression in degenerated IVDs. We detected the expression of POSTN, ß-catenin, and cleaved-caspase-3 (C-caspase3) in degenerated and non-degenerated IVD tissues of different grades (n = 8) using RT-qPCR, immunohistochemical staining, and western blotting analysis. Next, we explored the effects of recombinant periostin (rPOSTN) and isoquercitrin (Iso), an inhibitor of the Wnt/ß-catenin pathway, on NPCs apoptosis. Finally, we inhibited the expression of POSTN in degenerated NPCs in vivo and investigated the anti-apoptotic effect. The expression of ß-catenin, POSTN, and C-caspase3 in severe degenerative IVDs was significantly higher than that in mild degenerative IVDs. These findings were confirmed in rat and cell-based degenerative models. When treated with rPOSTN, the Wnt/ß-catenin pathway activity and cell apoptosis were time- and dose-dependent. However, rPOSTN-induced NPCs apoptosis decreased after iso-induced inhibition of the Wnt/ß-catenin pathway. POSTN inhibition reduced apoptosis but was restored by rPOSTN re-addition. Lastly, POSTN inhibition ameliorated puncture-induced IVDD in vivo. Overall, our study demonstrated that POSTN promotes NPCs apoptosis and aggravates degeneration by activating the Wnt/ß-catenin pathway.

Nlrp9b inflammasome restricts rotavirus infection in intestinal epithelial cells.

Rotavirus, a leading cause of severe gastroenteritis and diarrhoea in young children, accounts for around 215,000 deaths annually worldwide. Rotavirus specifically infects the intestinal epithelial cells in the host small intestine and has evolved strategies to antagonize interferon and NF-κB signalling, raising the question as to whether other host factors participate in antiviral responses in intestinal mucosa. The mechanism by which enteric viruses are sensed and restricted in vivo, especially by NOD-like receptor (NLR) inflammasomes, is largely unknown. Here we uncover and mechanistically characterize the NLR Nlrp9b that is specifically expressed in intestinal epithelial cells and restricts rotavirus infection. Our data show that, via RNA helicase Dhx9, Nlrp9b recognizes short double-stranded RNA stretches and forms inflammasome complexes with the adaptor proteins Asc and caspase-1 to promote the maturation of interleukin (Il)-18 and gasdermin D (Gsdmd)-induced pyroptosis. Conditional depletion of Nlrp9b or other inflammasome components in the intestine in vivo resulted in enhanced susceptibility of mice to rotavirus replication. Our study highlights an important innate immune signalling pathway that functions in intestinal epithelial cells and may present useful targets in the modulation of host defences against viral pathogens.

Improving masticatory and swallowing ability of postoperative oral and maxillofacial tumor patients by telerehabilitation-A randomized controlled trial.

OBJECTIVE: To evaluate the effect of telerehabilitation on oral function of oral and maxillofacial tumor patients. DESIGN: Unicentral, single-blind, randomized controlled trial. SETTING: Community. SUBJECTS: Patients with primary oral and maxillofacial tumor receiving surgical treatment. INTERVENTIONS: Telerehabilitation guidance from therapists. MAIN MEASURES: At the beginning of training (T0) and 1 month (T1), 3 months (T2) and 6 months (T3) after training, patients' masticatory ability (mastication efficiency-masticatory performance evaluating gum, maximum bite force and mouth opening) and swallowing ability (water swallowing test) was measured. Modified Sato questionnaire and MD Anderson dysphagia inventory (MDADI) were used for self-evaluation of masticatory and swallowing ability. RESULTS: A total of 64 participants (intervention: 33; control: 31) were included. The masticatory efficiency scores of the intervention group were significantly better than those of the control group at T2 (intervention: 3.67 (0.48); control: 3.03 (0.85)) and T3 (intervention: 4.20 (0.30); control: 3.50 (0.79)); and maximum mouth opening was better at T2 (intervention: 3.18 (0.59); control: 2.77 (0.54)) and T3 (intervention: 3.54 (0.58); control: 3.09 (0.41)). In water swallowing test, the intervention group had better scores at T2 and T3. The scores of MDADI scale in intervention group were better than those in the control group after 3 months of training. In subgroup analysis, the intervention group of oral cancer patients had better swallowing function at T2 and T3, but no significant difference was found in the subgroup of oropharyngeal cancer. CONCLUSIONS: Telerehabilitation could greatly improve the long-term (3-6 months) training effect under the condition of greatly saving medical resources and reducing personnel contact.

Student Behavior Detection in the Classroom Based on Improved YOLOv8.

Accurately detecting student classroom behaviors in classroom videos is beneficial for analyzing students' classroom performance and consequently enhancing teaching effectiveness. To address challenges such as object density, occlusion, and multi-scale scenarios in classroom video images, this paper introduces an improved YOLOv8 classroom detection model. Firstly, by combining modules from the Res2Net and YOLOv8 network models, a novel C2f_Res2block module is proposed. This module, along with MHSA and EMA, is integrated into the YOLOv8 model. Experimental results on a classroom detection dataset demonstrate that the improved model in this paper exhibits better detection performance compared to the original YOLOv8, with an average precision (mAP@0.5) increase of 4.2%.

Achilles' Heel-The Significance of Maintaining Microenvironmental Homeostasis in the Nucleus Pulposus for Intervertebral Discs.

The dysregulation of intracellular and extracellular environments as well as the aberrant expression of ion channels on the cell membrane are intricately linked to a diverse array of degenerative disorders, including intervertebral disc degeneration. This condition is a significant contributor to low back pain, which poses a substantial burden on both personal quality of life and societal economics. Changes in the number and function of ion channels can disrupt the water and ion balance both inside and outside cells, thereby impacting the physiological functions of tissues and organs. Therefore, maintaining ion homeostasis and stable expression of ion channels within the cellular microenvironment may prove beneficial in the treatment of disc degeneration. Aquaporin (AQP), calcium ion channels, and acid-sensitive ion channels (ASIC) play crucial roles in regulating water, calcium ions, and hydrogen ions levels. These channels have significant effects on physiological and pathological processes such as cellular aging, inflammatory response, stromal decomposition, endoplasmic reticulum stress, and accumulation of cell metabolites. Additionally, Piezo 1, transient receptor potential vanilloid type 4 (TRPV4), tension response enhancer binding protein (TonEBP), potassium ions, zinc ions, and tungsten all play a role in the process of intervertebral disc degeneration. This review endeavors to elucidate alterations in the microenvironment of the nucleus pulposus during intervertebral disc degeneration (IVDD), with a view to offer novel insights and approaches for exploring therapeutic interventions against disc degeneration.

Role of Nrf2 and HO-1 in intervertebral disc degeneration.

Intervertebral disc degeneration (IDD) is a common age-related disease with clinical manifestations of lumbar and leg pain and limited mobility. The pathogenesis of IDD is mainly mediated by the death of intervertebral disc (IVD) cells and the imbalance of extracellular matrix (ECM) synthesis and degradation. Oxidative stress and inflammatory reactions are the important factors causing this pathological change. Therefore, the regulation of reactive oxygen species and production of inflammatory factors may be an effective strategy to delay the progression of IDD. In recent years, nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream regulated protein heme oxygenase-1 (HO-1) have received special attention due to their antioxidant, anti-inflammatory and anti-apoptotic protective effects. Recent studies have elucidated the important role of these two proteins in the treatment of IDD disease. However, Nrf2 and HO-1 have not been systematically reported in IDD-related diseases. Therefore, this review describes the biological characteristics of Nrf2 and HO-1, the relationship between Nrf2- and HO-1-regulated oxidative stress and the inflammatory response and IDD, and the progress in research on some extracts targeting Nrf2 and HO-1 to improve IDD. Understanding the role and mechanism of Nrf2 and HO-1 in IDD may provide novel ideas for the clinical treatment and development of Nrf2- and HO-1-targeted drugs.

Proanthocyanidins inhibit the apoptosis and aging of nucleus pulposus cells through the PI3K/Akt pathway delaying intervertebral disc degeneration.

BACKGROUND: Low back pain is a common symptom of intervertebral disc degeneration (IDD), which seriously affects the quality of life of patients. The abnormal apoptosis and senescence of nucleus pulposus (NP) cells play important roles in the pathogenesis of IDD. Proanthocyanidins (PACs) are polyphenolic compounds with anti-apoptosis and anti-aging effects. However, their functions in NP cells are not yet clear. Therefore, this study was performed to explore the effects of PACs on NP cell apoptosis and aging and the underlying mechanisms of action. METHODS: Cell viability was evaluated by cell counting kit-8 (CCK-8) assay. The apoptosis rate was determined TUNEL assays. Levels of apoptosis-associated molecules (Bcl-2, Bax, C-caspase-3 and Caspase-9) were evaluated via western blot. The senescence was observed through SA-ß-gal staining and western blotting analysis was performed to observe the expression of senescence-related molecules (p-P53, P53, P21 and P16). RESULTS: Pretreatment with PACs exhibited protective effects against IL-1ß-induced NP cell apoptosis including apoptosis rate, expressions of proapoptosis and antiapoptosis related genes and protein. PACs could also alleviate the increase of p-p53, P21, and P16 in IL-1ß-treated NP cells. SA-ß-gal staining showed that IL-1ß-induced senescence of NP cells was prevented by PACs pertreatment. In addition, PACs activated PI3K/Akt pathway in IL-1ß-stimulated NP cells. However, these protected effects were inhibited after LY294002 treatment. CONCLUSION: The results of the present study showed that PACs inhibit IL-1ß-induced apoptosis and aging of NP cells by activating the PI3K/Akt pathway, and suggested that PACs have therapeutic potential for IDD.

Grape Seed Proanthocyanidins Exert a Neuroprotective Effect by Regulating Microglial M1/M2 Polarisation in Rats with Spinal Cord Injury.

Spinal cord injury (SCI) is a highly disabling disorder for which few effective treatments are available. Grape seed proanthocyanidins (GSPs) are polyphenolic compounds with various biological activities. In our preliminary experiment, GSP promoted functional recovery in rats with SCI, but the mechanism remains unclear. Therefore, we explored the protective effects of GSP on SCI and its possible underlying mechanisms. We found that GSP promoted locomotor recovery, reduced neuronal apoptosis, increased neuronal preservation, and regulated microglial polarisation in vivo. We also performed in vitro studies to verify the effects of GSP on neuronal protection and microglial polarisation and their potential mechanisms. We found that GSP regulated microglial polarisation and inhibited apoptosis in PC12 cells induced by M1-BV2 cells through the Toll-like receptor 4- (TLR4-) mediated nuclear factor kappa B (NF-κB) and phosphatidylinositol 3-kinase/serine threonine kinase (PI3K/AKT) signaling pathways. This suggests that GSP regulates microglial polarisation and prevents neuronal apoptosis, possibly by the TLR4-mediated NF-κB and PI3K/AKT signaling pathways.

High-peak-power 786†nm and 452†nm lasers based on 1064†nm intracavity-driven cascaded nonlinear optical frequency conversion.

We demonstrated high-peak-power 786 nm and 452 nm lasers based on 1064 nm intracavity-driven cascaded nonlinear optical frequency conversion (CNOFC). The 1064 nm fundamental wave generated from the LD-side-pumped Nd:YAG was first intracavity converted to 1572 nm by a noncritically phase-matched KTP OPO. Then a LBO-based second harmonic generation of 1572 nm was served as cascaded process to produce 786 nm laser radiation. The maximum average output power at 786 nm was 1.34 W, corresponding to a pulse peak power of 14.2 kW with 11.2 ns pulse width and 8 kHz pulse repetition rate. Furthermore, a third stage of sum frequency mixing between 786 nm and 1064 nm was designed to achieve the blue emission at 452 nm. The 452 nm blue laser delivers 263 mW, 6.2 ns pulses with a peak power of 5.3 kW, paving the way for achieving high-peak-power blue lasers.

An Ugi-like Biosynthetic Pathway Encodes Bombesin Receptor Subtype-3 Agonists.

Isocyanide functional groups can be found in a variety of natural products. Rhabduscin is one such isocyanide-functionalized immunosuppressant produced in Xenorhabdus and Photorhabdus gammaproteobacterial pathogens, and deletion of its biosynthetic gene cluster inhibits virulence in an invertebrate animal infection model. Here, we characterized the first "opine-glycopeptide" class of natural products termed rhabdoplanins, and strikingly, these molecules are spontaneously produced from rhabduscin via an unprecedented multicomponent "Ugi-like" reaction sequence in nature. The rhabdoplanins also represent new lead G protein-coupled receptor (GPCR) agonists, stimulating the bombesin receptor subtype-3 (BB3) GPCR.

A high-peak-power orthogonally-polarized multi-wavelength laser at 1.6-1.7 µm based on the cascaded nonlinear optical frequency conversion.

We demonstrated a high-peak-power orthogonally polarized multi-wavelength laser at 1.6-1.7 µm based on the intracavity cascaded nonlinear optical frequency conversion (CNOFC). This CNOFC can be characterized by a configuration of "series-parallel optical circuit", where the OPO pumped Raman conversion operates in the "series-mode" and orthogonally-polarized waves are simultaneously converted in the "parallel-mode". The fundamental wave at 1064 nm was first simultaneously converted to orthogonally-polarized 1534 and 1572 nm by the x-cut KTA and KTP optical parametric oscillation (OPO), respectively. Then the x-cut KTA and KTP acted as the Raman crystal to each other with the X(ZZ)X Raman configuration, converting the OPO signals to multi-order Raman emissions with the wavelengths at 1601, 1632, 1673, 1697, 1752 and 1767nm. A maximum total average output power of 1.2 W and a minimum pulse width of 10.5 ns were achieved from this CNOFC-based laser, corresponding to a pulse peak power of 28.5 kW and a pulse energy of 0.3 mJ.

High power simultaneous dual-wavelength CW and passively-Q-switched laser operation of LD pumped Tm:YLF at 1.9 and 2.3 µm.

Simultaneous dual-wavelength laser oscillation of Tm:YLF at 1.9 and 2.3 µm were successfully realized. The three-mirror cavity was exploited to study dual-wavelength laser performance, which is formed by a shared input mirror and two independent output couplers for the two laser wavelengths. Under an absorbed pump power of 15.2 W, the maximum CW output powers of 5.49 W around 1908nm and 1.12 W around 2305 nm were simultaneously obtained, corresponding to a total optical-to-optical conversion efficiency of 43.5%. A Cr2+:ZnSe was further used to passively Q-switch the dual-wavelength laser, generating pulses with pulse widths of 554 ns at 1.9 µm and 4 µs at 2.3 µm. To the best of our knowledge, this is the first report on the dual-wavelength laser operation of Tm3+-single-doped solid-state laser at 1.9 and 2.3 µm. The higher optical conversion efficiency, smaller wavelength competition effect and simultaneous dual-wavelength output make this Tm-doped solid-state laser have potential application in medical surgery.

Tuning the correlated color temperature of white light-emitting diodes resembling Planckian locus.

We report a new electrically tunable color filter to actively adjust the correlated color temperature of white light-emitting diodes. With four passive cholesteric films and an active polarization rotator, both circular polarizations of the incident light are utilized to generate complementary blue and yellow colors. The blue/yellow ratio can be tuned by the applied voltage of the polarization rotator. In experiment, the tunable color filter offers a reasonably wide tuning range (1900 K and 2400 K), which resembles the Planckian locus. This design is promising for next generation smart lighting.