Interleukin-18 in chronic pain: Focus on pathogenic mechanisms and potential therapeutic targets.

Chronic pain has been proven to be an independent disease, other than an accompanying symptom of certain diseases. Interleukin-18 (IL-18), a pro-inflammatory cytokine with pleiotropic biological effects, participates in immune modulation, inflammatory response, tumor growth, as well as the process of chronic pain. Compelling evidence suggests that IL-18 is upregulated in the occurrence of chronic pain. Antagonism or inhibition of IL-18 expression can alleviate the occurrence and development of chronic pain. And IL-18 is located in microglia, while IL-18R is mostly located in astrocytes in the spinal cord. This indicates that the interaction between microglia and astrocytes mediated by the IL-18/IL-18R axis is involved in the occurrence of chronic pain. In this review, we described the role and mechanism of IL-18 in different types of chronic pain. This review provides strong evidence that IL-18 is a potential therapeutic target in pain management.

Chiral photonic topological states in Penrose quasicrystals.

Electromagnetic topological edge states typically are created in photonic systems with crystalline symmetry and these states emerge because of the topological feature of bulk Bloch bands in momentum space according to the bulk-edge correspondence principle. In this work, we demonstrate the existence of chiral topological electromagnetic edge states in Penrose-tiled photonic quasicrystals made of magneto-optical materials, without relying on the concept of bulk Bloch bands in momentum space. Despite the absence of bulk Bloch bands, which naturally defiles the conventional definition of topological invariants in momentum space characterizing these states, such as the Chern number, we show that some bandgaps in these photonic quasicrystals still could host unidirectional topological electromagnetic edge states immune to backscattering in both cylinders-in-air and holes-in-slab configurations. Employing a real-space topological invariant based on the Bott index, our calculations reveal that the bandgaps hosting these chiral topological edge states possess a nontrivial Bott index of ±1, depending on the direction of the external magnetic field. Our work opens the door to the study of topological states in photonic quasicrystals.

The prevalence and risk of developing major depression among individuals with subthreshold depression in the general population.

BACKGROUND: Subthreshold depression could be a significant precursor to and a risk factor for major depression. However, reliable estimates of the prevalence and its contribution to developing major depression under different terminologies depicting subthreshold depression have to be established. METHODS: By searching PubMed and Web of Science using predefined inclusion criteria, we included 1 129 969 individuals from 113 studies conducted. The prevalence estimates were calculated using the random effect model. The incidence risk ratio (IRR) was estimated by measuring the ratio of individuals with subthreshold depression who developed major depression compared to that of non-depressed individuals from 19 studies (88, 882 individuals). RESULTS: No significant difference in the prevalence among the different terminologies depicting subthreshold depression (Q = 1.96, p = 0.5801) was found. By pooling the prevalence estimates of subthreshold depression in 113 studies, we obtained a summary prevalence of 11.02% [95% confidence interval (CI) 9.78-12.33%]. The youth group had the highest prevalence (14.17%, 95% CI 8.82-20.55%), followed by the elderly group (12.95%, 95% CI 11.41-14.58%) and the adult group (8.92%, 95% CI 7.51-10.45%). Further analysis of 19 studies' incidence rates showed individuals with subthreshold depression had an increased risk of developing major depression (IRR = 2.95, 95% CI 2.33-3.73), and the term minor depression showed the highest IRR compared with other terms (IRR = 3.97, 95% CI 3.17-4.96). CONCLUSIONS: Depression could be a spectrum disorder, with subthreshold depression being a significant precursor to and a risk factor for major depression. Proactive management of subthreshold depression could be effective for managing the increasing prevalence of major depression.

Toll-like Receptor 2-Melatonin Feedback Loop Regulates the Activation of Spinal NLRP3 Inflammasome in Morphine-Tolerant Rats.

BACKGROUND AND PURPOSE: Morphine is amongst the most effective analgesics available for the management of severe pain. However, prolonged morphine treatment leads to analgesic tolerance which limits its clinical usage. Previous studies have demonstrated that melatonin ameliorates morphine tolerance by reducing neuroinflammation. However, little is known about the relationship between Toll like receptor 2 (TLR2) and neuroinflammation in morphine tolerance. The aim of this study was to explore the role of TLR2 in morphine tolerance and its connections with melatonin and Nod-like receptor protein 3 (NLRP3) inflammasome. METHODS: Sprague-Dawley rats were treated with morphine for 7 days and tail-flick latency test was performed to identify the induction of analgesic tolerance. The roles of TLR2 in microglia activation and morphine tolerance were assessed pharmacologically, and the possible interactions between melatonin, TLR2 and NLRP3 inflammasome were investigated. KEY RESULTS: Morphine tolerance was accompanied by increased TLR2 expression and NLRP3 inflammasome activation in spinal cord. whereas melatonin level was down-regulated. Chronic melatonin administration resulted in a reduced TLR2 expression and NLRP3 inflammasome activation. Moreover, the analgesic effect of morphine was partially restored. Inhibition of TLR2 suppressed the microglia and NLRP3 inflammasome activation, as well as restored the spinal melatonin level while attenuated the development of morphine tolerance. Furthermore, the inhibition of microglia activation ameliorated morphine tolerance via inhibiting TLR2-NLRP3 inflammasome signaling in spinal cord. CONCLUSION: In this study, we directly demonstrate a TLR2-melatonin negative feedback loop regulating microglia and NLRP3 inflammasome activation during the development of morphine tolerance.

Missing data imputation, prediction, and feature selection in diagnosis of vaginal prolapse.

BACKGROUND: Data loss often occurs in the collection of clinical data. Directly discarding the incomplete sample may lead to low accuracy of medical diagnosis. A suitable data imputation method can help researchers make better use of valuable medical data. METHODS: In this paper, five popular imputation methods including mean imputation, expectation-maximization (EM) imputation, K-nearest neighbors (KNN) imputation, denoising autoencoders (DAE) and generative adversarial imputation nets (GAIN) are employed on an incomplete clinical data with 28,274 cases for vaginal prolapse prediction. A comprehensive comparison study for the performance of these methods has been conducted through certain classification criteria. It is shown that the prediction accuracy can be greatly improved by using the imputed data, especially by GAIN. To find out the important risk factors to this disease among a large number of candidate features, three variable selection methods: the least absolute shrinkage and selection operator (LASSO), the smoothly clipped absolute deviation (SCAD) and the broken adaptive ridge (BAR) are implemented in logistic regression for feature selection on the imputed datasets. In pursuit of our primary objective, which is accurate diagnosis, we employed diagnostic accuracy (classification accuracy) as a pivotal metric to assess both imputation and feature selection techniques. This assessment encompassed seven classifiers (logistic regression (LR) classifier, random forest (RF) classifier, support machine classifier (SVC), extreme gradient boosting (XGBoost) , LASSO classifier, SCAD classifier and Elastic Net classifier)enhancing the comprehensiveness of our evaluation. RESULTS: The proposed framework imputation-variable selection-prediction is quite suitable to the collected vaginal prolapse datasets. It is observed that the original dataset is well imputed by GAIN first, and then 9 most significant features were selected using BAR from the original 67 features in GAIN imputed dataset, with only negligible loss in model prediction. BAR is superior to the other two variable selection methods in our tests. CONCLUDES: Overall, combining the imputation, classification and variable selection, we achieve good interpretability while maintaining high accuracy in computer-aided medical diagnosis.

Developmental characteristics of visual evoked potentials to different stimulation in normal children.

OBJECTIVE: To determine the developmental characteristics of flash visual evoked potentials (FVEP) and pattern-reversal visual evoked potentials (PVEP) of healthy children. METHODS: The data were collected with a Keypoint Workstation 9033A07; 168 children (2 months-13 years) were tested with FVEP and 101 (4-13 years) were tested with PVEP. RESULTS: A triphasic waveform with clear components (N2, P2, and N3) was recorded steadily after 1 year, with occurrence rates over 97% at all frequencies. FVEP latency significantly decreased with age. The amplitude difference of FVEP was greater for binocular than monocular fields. FVEP amplitude increased and amplitude differences decreased with stimulation frequency. The occurrence rate of PVEP was 100% after 4 years, and PVEP latency was significantly prolonged with age. N75 and P100 amplitudes and the N75-P100 amplitude difference increased with field of vision. CONCLUSION: FVEP can be evoked in normal children at less than 2 Hz. Stimulation frequency can be adjusted to improve early detection and verification of subclinical lesions. The PVEP waveform is simple and stable, and its results are easier to analyze and interpret than FVEP, but it is limited by visual acuity and fixation force, whereas FVEP is affected less by visual acuity. but it is necessary to establish normal reference values of each age in each laboratory because of complicated analysis. According to the specific situation of the patient (vision, fixation) and clinical demand, we need to choose the right stimulation.

Spatially Modulated Fiber Speckle for High-Sensitivity Refractive Index Sensing.

A fiber speckle sensor (FSS) based on a tapered multimode fiber (TMMF) has been developed to measure liquid analyte refractive index (RI) in this work. By the lateral and axial offset of input light into TMMF, several high-order modes are excited in TMMF, and the speckle pattern is spatially modulated, which affects an asymmetrical speckle pattern with a random intensity distribution at the output of TMMF. When the TMMF is immersed in the liquid analyte with RI variation, it influences the guided modes, as well as the mode interference, in TMMF. A digital image correlations method with zero-mean normalized cross-correlation coefficient is explored to digitize the speckle image differences, analyzing the RI variation. It is found that the lateral- and axial-offsets-induced speckle sensor can enhance the RI sensitivity from 6.41 to 19.52 RIU-1 compared to the one without offset. The developed TMMF speckle sensor shows an RI resolution of 5.84 × 10-5 over a linear response range of 1.3164 to 1.3588 at 1550 nm. The experimental results indicate the FSS provides a simple, efficient, and economic approach to RI sensing, which exhibits an enormous potential in the image-based ocean-sensing application.

Efficacy and safety of intravenous high-dose immunoglobulin in treatment of the severe form of Japanese encephalitis.

PURPOSE: To explore the efficacy and safety of intravenous immunoglobulin (IVIG) in the treatment of severe Japanese encephalitis (JE). METHODS: A retrospective study of 124 children diagnosed with the severe or very severe form of JE was undertaken. There were 62 cases in the IVIG group and control group. The efficacy, safety, and tolerability of IVIG were evaluated 3 days, as well as 1, 2, and 3 weeks after IVIG, respectively, and the prognosis was assessed at 6 months. RESULTS: Cox regression survival analysis suggested that the IVIG group reached the criteria for efficacious treatment faster than that in the control group. The duration of unconsciousness and the number of days of seizures, a dull response to light, the pyramidal sign, and meningeal-irritation sign in the IVIG group were shorter than those in the control group (p < 0.05). The number of complications occurring in the IVIG group (including gastrointestinal bleeding and pneumonia) was less than that in the control group (p < 0.05). Cox regression survival analysis suggested that age (p = 0.003) and imaging abnormalities (p = 0.042) had an effect on the efficacy of IVIG treatment. The Liverpool Outcome Score at 6 months showed that the prognosis of the IVIG group was better than that of the control group (p < 0.05). IVIG treatment was safe and tolerable. CONCLUSION: IVIG showed good efficacy, safety, and tolerance for treatment of the severe form of JE. The age and imaging abnormalities of patients affect the efficacy of IVIG treatment.

Oxidative stress responses in two marine diatoms during acute n-butyl acrylate exposure and the toxicological evaluation with the IBRv2 index.

n-Butyl acrylate (nBA), a typical hazardous and noxious substance (HNS), is the largest-volume acrylate ester used to produce various types of polymers. With the increasing volume of nBA subject to maritime transportation, its accidental leakage poses a great risk to the marine organisms. Therefore, it is necessary to evaluate the ecological risk of nBA in marine environments. In this study, two species of marine microalgae, Skeletonema costatum and Phaeodactylum tricornutum, were used to explore the toxic effects of nBA based on their growth, pigment content, and oxidative stress. The growth of each species was significantly inhibited by nBA, showing a 96 h-EC50 value of 2.23 mg/L for P. tricornutum and 8.19 mg/L for S. costatum, respectively. Although chlorophylls a and c exerted a hormesis effect in P. tricornutum, contents of pigments generally decreased at high concentrations. In P. tricornutum, all detected antioxidants (reduced glutathione, GSH; superoxide dismutase, SOD; catalase, CAT; and glutathione peroxidase, GPx) were stimulated at concentrations ranging from 1.50 to 3.82 mg/L. However, these elevations were not enough to reduce the oxidative damage caused by nBA, because the content of malondialdehyde (MDA) increased continuously during 96-h exposure. For S. costatum, the activities of only two antioxidants (GSH and CAT) were enhanced, which is enough to prevent the MDA content from rising, even at higher concentrations of nBA (5-10 mg/L). The Integrated Biomarker Response Version 2 (IBRv2) index that combines responses of the above five oxidative stress biomarkers, was not only correlated positively with nBA concentration but could also indicate the occurrence of oxidative stress caused by acute concentration of nBA. These findings showed that P. tricornutum was sensitive to nBA compared to S. costatum, and the IBRv2 index was an effective tool for evaluating ecotoxicological effects on marine microalgae due to nBA spills.

Activation of spinal PDGFRß in microglia promotes neuronal autophagy via p38 MAPK pathway in morphine-tolerant rats.

The adverse side effects of opioids, especially antinociceptive tolerance, limit their clinical application. A recent study reported that platelet-derived growth factor receptor ß (PDGFRß) blockage selectively inhibited morphine tolerance. Autophagy has been reported to contribute to the cellular and behavioral responses to morphine. However, little is known about the relationship between PDGFRß and autophagy in the mechanisms of morphine tolerance. In this study, rats were intrathecally administered with morphine twice daily for 7 days to induce antinociceptive tolerance, which was evaluated using a tail-flick latency test. By administration autophagy inhibitor 3-Methyladenine, PDGFRß inhibitor imatinib, p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 hydrochloride and minocycline hydrochloride, western blot, immunofluorescence, and transmission electron microscopy techniques were used to elucidate the roles of PDGFRß, autophagy, and related signaling pathways in morphine tolerance. This study demonstrated for the first time that spinal PDGFRß in microglia promotes autophagy in gamma-aminobutyric acid (GABA) interneurons through activating p38 MAPK pathway during the development of morphine tolerance, which suggest a potential strategy for preventing the development of morphine tolerance clinically, thereby improving the use of opioids in pain management.

NADPH-Oxidase 2 Promotes Autophagy in Spinal Neurons During the Development of Morphine Tolerance.

Repeated morphine administration results in analgesic tolerance. However, the underlying mechanism of morphine analgesic tolerance remains unclear. NADPH-oxidase 2 (NOX2) is the first discovered NADPH oxidase, which mainly functions to produce reactive oxygen species. Its specific role in morphine tolerance has not been fully investigated. In this work, we found that chronic morphine administration significantly increased the expression of NOX2 in spinal cord. Pretreatment of NOX2 inhibitor blocked the upregulation of NOX2 and autophagy markers, including LC3B and P62, and consequently the development of morphine tolerance. NOX2 and LC3B were both colocalized with NeuN in spinal dorsal horn in morphine-tolerant rats. Our results suggest that the increased autophagy activity in spinal neurons promoted by NOX2 activation contributes to the development of morphine tolerance. NOX2 may be considered as a new therapeutic target for morphine tolerance.

A comprehensive association analysis between homocysteine metabolic pathway gene methylation and ischemic stroke in a Chinese hypertensive population.

BACKGROUND: Ischemic stroke (IS) is a serious global health burden. In order to improve our understanding of the risk factors associated with IS, we investigated the combined effect of the methylation of five genes related to the metabolism of homocysteine on developing IS. METHODS: Quantitative methylation-specific PCR was used to measure the levels of promoter methylation in hypertensive and stroke patients. The cutoff value calculated by the maximum Youden index was used to classify the levels of gene methylation as hypomethylation and hypermethylation. Logistic regression was used to explore the relationship between gene methylation and IS. RESULTS: The methylation levels of the genes encoding methylenetetrahydrofolate dehydrogenase 1 [MTHFD1], cystathionine ß-synthase [CBS], and dihydrofolate reductase [DHFR] in hypertensive patients were higher than those in stroke patients (all p < 0.01). MTHFD1 hypermethylation, CBS hypermethylation, and DHFR hypermethylation were protective factors for stroke after adjustment for confounding factors. Compared with individuals carrying none of the biomarkers, the ORs [95% CIs] for stroke of those with 1 and 2 elevated biomarkers were 4.068 [1.670-9.913] and 15.345 [6.198-37.994] after adjustment for confounding factors. The participants with a larger number of biomarkers had an increased risk of stroke (p for trend <0.001). For the combination biomarkers, the area under the curve of the receiver operating characteristic was 0.716. CONCLUSION: A significant linear relationship between the number of elevated biomarkers and the risk of stroke has been observed, suggesting that elevations of these biomarkers could be used for potentially predicting the disease.

Vibration Sensor Based on Hollow Biconical Fiber.

A hollow biconical fiber is proposed and experimentally demonstrated for vibration sensing. It is fabricated by creating an air micro-cavity in single-mode fiber, followed by tapering it. Experimental results show that the device is highly sensitive to bending with a sensitivity of 21.30 dB/m-1. When it is exposed to vibration, its transmission loss is modulated periodically, then based on the measured transmission, the vibration frequency can be demodulated accurately. The acoustic vibration testing results show that the proposed device can detect and demodulate the exciting acoustic frequency accurately and distinguish its sound intensity, and the maximum signal to noise ratio (SNR) achieves up to 59 dB. Moreover, cantilever beam testing proves its performance reliable. Additionally, the sensing head has the advantages of a lightweight, compact size (with a total length of less than 250 µm), and insensitivity of temperature. All these features indicate the proposed sensor has a promising potential in the engineering field.

Clinical characteristics of Epstein-Barr virus infection in the pediatric nervous system.

BACKGROUND: To investigate the clinical characteristics of Epstein-Barr virus (EBV) infection in the pediatric nervous system (NS). METHODS: We retrospectively analyzed the clinical data and follow-up results of 89 children with neurological damage caused by EBV who were hospitalized in the children's hospital of Chongqing Medical University from January 2008 to April 2019. RESULTS: EBV infection of the NS can occur at any time of the year. The highest incidence was seen in the age group of 0-4 years. Fever is the main clinical feature (74/89, 83.1%). The main clinical types were encephalitis/meningoencephalitis (64/89, 71.9%), acute myelitis (2/89, 2.2%), acute disseminated encephalomyelitis (ADEM) (3/89, 3.4%), Guillain-Barré Syndrome (GBS) (15/89, 16.9%), neurological damage caused by EBV-hemophagocytic lymphohistiocytosis (EBV-HLH) (4/89, 4.5%), and NS-post-transplant lymphoproliferative disorder (NS-PTLD) (1/89, 1.1%). Anti-N-methyl-D-aspartate receptor encephalitis was found during the convalescence of EBV encephalitis. EBV encephalitis/meningitis showed no symptoms of tonsillitis, lymph node enlargement, skin rash, hepatosplenomegaly. Acute motor axonal neuropathy is the chief complication in GBS caused by EBV. CONCLUSION: There were significant differences in neurological complications caused by EBV. The prognosis of EBV infection in the NS is generally good. These illnesses are often self-limiting. A few cases may show residual sequelae.

The pathways by which the marine diatom Thalassiosira sp. OUC2 biodegrades p-xylene, combined with a mechanistic analysis at the proteomic level.

A marine diatom, Thalassiosira sp. OUC2, was isolated from natural seawater collected from Daya Bay, China. This diatom degraded 1.25-40 mg L-1p-xylene within five days, at a removal efficiency exceeding 98%. Gas chromatography-mass spectrometer (GC-MS) analysis indicated that p-xylene was converted into 4-methylbenzyl alcohol, p-toluic acid, and p-cresol in the presence of strain OUC2. Meanwhile, proteomic analysis showed that, after exposure to p-xylene, several algal enzymes were significantly upregulated: including monooxygenase, alcohol dehydrogenase, benzaldehyde dehydrogenase, benzoate 1,2-dioxygenase, and catechol 2,3-dioxygenase. Moreover, ecotoxicological tests suggested that the intermediate metabolites were less toxic than the parent compound (p-xylene). Thalassiosira sp. OUC2 may thus be suitable for the remediation of p-xylene-contaminated marine environments.

Kinetic analysis and degradation mechanism for natural attenuation of xylenes under simulated marine conditions.

Microcosm experiments were conducted to examine the attenuation of selected chemicals, i.e. m-xylene (MX), o-xylene (OX) and p-xylene (PX), under simulated marine conditions. Natural attenuation and the contribution of oxidation, photodegradation, biodegradation and volatilization to total attenuation were evaluated. The development of attenuation was in agreement with pseudo-first-order kinetics for all xylenes. The half-lives of MX, OX, and PX under optimal conditions were 0.76, 0.74 and 0.88 days, respectively. Attenuation kinetics were proposed to analyze the natural attenuation of xylenes. The leading attenuation type of MX, OX, and PX was volatilization, and the attenuation rate constants (KV) were 0.5587, 0.6733, and 0.4821 d-1, respectively. Biodegradation of OX (Kb: 0.0003 d-1) was extremely inhibited. The attenuation kinetics presented the attenuation of xylenes in microcosm. The reaction kinetics could be applied to analyze the natural attenuation of chemicals. MX and OX can be converted to one another under certain conditions. Toluene and ethylbenzene were detected for OX in the OP (oxidation and photodegradation) experiment under simulated marine conditions. 4-Methylbenzyl alcohol, p-methyl benzaldehyde and p-toluic acid, as the major intermediates, were identified during the natural attenuation of PX using GC/MS.

Clinical Efficacy and Safety of Combination Therapy with Amlodipine and Olmesartan or an Olmesartan/Hydrochlorothiazide Compound for Hypertension: A Prospective, Open-Label, and Multicenter Clinical Trial in China.

BACKGROUND: Amlodipine (AML) is the initial therapy most commonly prescribed for patients with hypertension in China. However, AML monotherapy is often less effective in achieving blood pressure (BP) control than other agents. OBJECTIVE: We performed a clinical study to evaluate efficacy and safety of a combination therapy with AML, olmesartan (OLM), or an OLM/hydrochlorothiazide (HCTZ) compound for Chinese patients with mild-to-moderate hypertension. METHODS: In the clinical trial, patients were initially treated with OLM 20 mg/d combined with AML 5 mg/d. Then OLM was uptitrated to 40 mg/d or changed to an OLM/HCTZ (20/12.5 mg/d) compound if the patients did not reach the target of seated diastolic BP <90 mm Hg (<80 mm Hg in patients with diabetes) after 8 weeks. RESULTS: The overall response rate of the combination therapy was 59.2% (95% CI, 54.23%-63.97%) at Week 2 and gradually increased to 97.1% (95% CI, 94.93%-98.47%) at the end of the study (Week 16). CONCLUSIONS: The combination therapy with OLM or OLM/HCTZ was well tolerated. The total incidence of adverse events was 42.9% (n = 176). Most of the adverse events were mild in severity (39.5%; n = 162) and not associated with the drugs (33.2%). In conclusion, combination therapy with AML, OLM, or OLM/HCTZ can significantly lower BP safely and achieve a high BP control rate in patients with mild-to-moderate hypertension in China. ClinicalTrial.org identifier: ChiCTR-ONC-12001963.

Toxicological Assessment of Intermediates in Natural Attenuation of p-Xylene to Marine Microalgae.

The toxic effects of p-xylene, 4-methylbenzyl alcohol, p-methyl benzaldehyde, and p-toluic acid on two marine microalgae (Phaeodactylum tricornutum Bohlin, and Skeletonema costatum) were investigated. p-Xylene was the most toxic to Pha. tricornutum with a 96 h EC50 value of 6.76 mg L-1. Based on the 96 h EC50 values for two microalgae, the toxicity of the four chemicals, in descending order, was: p-xylene, p-methyl benzaldehyde, 4-methylbenzyl alcohol, then p-toluic acid. The results showed that the toxicity of the transformed products of p-xylene was lower than that of p-xylene.

Highly improved ethanol gas-sensing performance of mesoporous nickel oxides nanowires with the stannum donor doping.

Mesoporous nickel oxides (NiO) and stannum(Sn)-doped NiO nanowires (NWs) were synthesized by using SBA-15 templates with the nanocasting method. X-ray diffraction, transmission electron microscope, energy dispersive spectrometry, nitrogen adsorption/desorption isotherm and UV-vis spectrum were used to characterize the phase structure, components and microstructure of the as-prepared samples. The gas-sensing analysis indicated that the Sn-doping could greatly improve the ethanol sensitivity for mesoporous NiO NWs. With the increasing Sn content, the ethanol sensitivity increased from 2.16 for NiO NWs up to the maximum of 15.60 for Ni0.962Sn0.038O1.038, and then decreased to 12.24 for Ni0.946Sn0.054O1.054 to 100 ppm ethanol gas at 340 °C. The high surface area from the Sn-doping improved the adsorption of oxygen on the surface of NiO NWs, resulting in the smaller surface resistance in air. Furthermore, owing to the recombination of the holes in hole-accumulation lay with the electrons from the donor impurity level and the increasing the body defects for Sn-doping, the total resistance in ethanol gas enhanced greatly. It was concluded that the sensitivity of Sn-doped NiO NWs based sensor could be greatly improved by the higher surface area and high-valence donor substitution from Sn-doping.

Multistate passively mode-locked thulium-doped fiber laser with nonlinear amplifying loop mirror.

In this paper, a multistate passively mode-locked thulium-doped fiber laser with nonlinear amplifying loop mirror is reported. An ultra-high numerical aperture fiber is employed to compensate the cavity abnormal dispersion, and the net cavity dispersion value is fixed at -0.046 ps2. By changing the pump power, three different mode-locked regions, namely Q-switched mode-locking operation, mode-locking operation, and dual-wavelength mode-locking operation, are observed sequentially. When the pump power is raised to the threshold of 1.60 W, the transition state of the Q-switched mode locking begins to be observed. When the pump power increases from 2.88 W to 8.75 W, stable single-wavelength mode-locking operation is obtained. And the center wavelength is 1988.73 nm corresponding to the 3 dB spectral bandwidth of 11.21 nm. As the pump power is raised beyond 8.75 W, dual-wavelength mode-locking operation is developed, where the dual wavelengths are 1969.70 nm and 1984.12 nm with the 3 dB spectral bandwidth of ∼4.11 nm and ∼6.14 nm, respectively.