Potential of Mie-Fluorescence-Raman Lidar to Profile Chlorophyll a Concentration in Inland Waters.

Vertical distribution of phytoplankton is crucial for assessing the trophic status and primary production in inland waters. However, there is sparse information about phytoplankton vertical distribution due to the lack of sufficient measurements. Here, we report, to the best of our knowledge, the first Mie-fluorescence-Raman lidar (MFRL) measurements of continuous chlorophyll a (Chl-a) profiles as well as their parametrization in inland water. The lidar-measured Chl-a during several experiments showed good agreement with the in situ data. A case study verified that MFRL had the potential to profile the Chl-a concentration. The results revealed that the maintenance of subsurface chlorophyll maxima (SCM) was influenced by light and nutrient inputs. Furthermore, inspired by the observations from MFRL, an SCM model built upon surface Chl-a concentration and euphotic layer depth was proposed with root mean square relative difference of 16.5% compared to MFRL observations, providing the possibility to map 3D Chl-a distribution in aquatic ecosystems by integrated active-passive remote sensing technology. Profiling and modeling Chl-a concentration with MFRL are expected to be of paramount importance for monitoring inland water ecosystems and environments.

Experimental demonstration of spectral suppression effect improvement for multi-longitudinal mode high-spectral-resolution lidar.

The multi-longitudinal mode high-spectral-resolution lidar (MLM-HSRL) is an effective technique for detecting atmospheric optical characteristics of aerosols. Due to the excessive longitudinal mode numbers, the current MLM-HSRL cannot obtain a well spectral suppression effect, which seriously affects the retrieval accuracy of the optical characteristic parameters. In this paper, a new index called Longitudinal Mode Rejection Ratio (LMRR) has been proposed to evaluate the spectral suppression effect of the MLM-HSRL; a novel mismatch error and mode control (MEMC) technique is proposed to improve the spectral suppression effect of the MLM-HSRL, which contributes to developing the scientific potential of the MLM-HSRL for aerosol remote sensing. Based on our self-developed MLM laser, through controlling the longitudinal mode frequency-pulled shift of the MLM laser, adjusting the total mismatch error, and reducing the longitudinal mode numbers, we realize the LMRR index improved from about 5 to over 30, and the working stability of the system is also promoted by decreasing the longitudinal mode numbers. The experiment well improves the spectral suppression effect and verifies the effectiveness of the proposed MEMC technique. To the best of our knowledge, for the first time, the study addresses the conundrum of the lower spectral suppression effect for the MLM-HSRL. This work would help to provide a powerful support for the high-precision, long-term, and stable operation of the MLM-HSRL in the future.

High-spectral-resolution LIDAR based on a few-longitudinal mode laser for aerosol and cloud characteristics detection.

A novel implementation of high-spectral-resolution LIDAR based on a passively Q-switched few-longitudinal mode laser (PQFLM-HSRL) is proposed, and the prototype is built for detecting aerosol and cloud characteristics. The spatial-temporal distributions of the aerosol and cloud are continuously observed by the PQFLM-HSRL for the first time, to the best of our knowledge. Based on observation, we present the retrieval results of backscatter coefficient, particle linear depolarization ratio, and LIDAR ratio, and these intensive parameters are used to classify the aerosol and cloud into different types. Particularly, we have observed mix-phased clouds. The resulting aerosol optical depths (AODs) are highly consistent with CE-318, the Sun photometer measurements of the local National Meteorological Station (NMS), which verify the retrieval accuracy and the system stability. In addition, the retrieved AODs also characterize the ambient air quality, which show a high correlation with the measured PM2.5 concentrations. The implementation of the PQFLM-HSRL provides a new method for atmospheric feature detection, which shows superior scientific potential for further study on climate change and environmental health.

Emerging transparent conducting oxides material: 2-dimensional plasmonic Zn doped CuGaO2 nanoplates for Q-switched fiber laser.

A passively Q-switched Er3+ doped fiber laser has been realized by using Zn doped hexagonal CuGaO2 (CGZO) nanoplates (NPs) as a saturable absorber (SA) for the first time. The CGZO NPs SA film exhibits strong saturable absorption property, meanwhile with a small nonsaturable loss of 5.179%, and the modulation depth is up to 40.821%. A stable passively Q-switched laser, which was centered at 1559.75 nm, was achieved, and the threshold was as low as 42 mW. With an increase of the pump power from 42mW to 361mW, the pulse duration decreases from 36 µs to 1.71 µs, and the maximum output power of 12.1 mW is achieved. Particularly, the optical-optical conversion efficiency of the Q-Switched laser based on CGZO NPs reached 3.76%. Due to whispering-gallery-mode (WGM) resonance in CGZO NPs, the nonlinear optical response of CGZO NPs has been enhancement. These findings demonstrate that CGZO NPs are promising SA for fabricating high-efficiency and low-threshold pulse lasers.

Assessment of pesticide residues and gene expression in common carp exposed to atrazine and chlorpyrifos: Health risk assessments.

This study assessed the impacts of atrazine (ATR), chlorpyrifos (CPF) and combined ATR/CPF exposure on the kidney of common carp (Cyprinus carpio L.). The carp were sampled after a 40-d exposure to CPF and ATR, individually or in combination, followed by a 40-d recovery to measure the expression levels of heat shock proteins genes (HSP60, HSP70 and HSP90) and pesticide residues in the kidney tissue. The results revealed that the mRNA and protein levels of HSP60, HSP70 and HSP90 were induced in the kidney of common carp by ATR, CPF, and ATR/CPF mixture. The accumulated amounts of ATR, CPF, and their metabolites in the kidney tissues exhibited dose-dependency. These results exhibited that increasing concentration of ATR and CPF in the environment causes considerable stress for common carp, suggesting that the expression levels of HSP60, HSP70 and HSP90 may act as potential biomarkers for assessing the environmental ATR and CPF risk for carp.

Comprehensive, Continuous, and Vertical Measurements of Seawater Constituents with Triple-Field-of-View High-Spectral-Resolution Lidar.

Measuring the characteristics of seawater constituent is in great demand for studies of marine ecosystems and biogeochemistry. However, existing techniques based on remote sensing or in situ samplings present various tradeoffs with regard to the diversity, synchronism, temporal-spatial resolution, and depth-resolved capacity of their data products. Here, we demonstrate a novel oceanic triple-field-of-view (FOV) high-spectral-resolution lidar (HSRL) with an iterative retrieval approach. This technique provides, for the first time, comprehensive, continuous, and vertical measurements of seawater absorption coefficient, scattering coefficient, and slope of particle size distribution, which are validated by simulations and field experiments. Furthermore, it depicts valuable application potentials in the accuracy improvement of seawater classification and the continuous estimation of depth-resolved particulate organic carbon export. The triple-FOV HSRL with high performance could greatly increase the knowledge of seawater constituents and promote the understanding of marine ecosystems and biogeochemistry.

Enhancing Q-Switched Fiber Laser Performance Based on Reverse Saturable and Saturable Absorption Properties of CuCrO2 Nanoparticle-Polyimide Films.

We demonstrate CuCrO2 (CCO) nanoparticle (NP)-polyimide (PI) composite film as a saturable absorber (SA) to regulate the output characteristics of passively Q-switched fiber laser at 1.55 µm. Based on the reverse saturable and saturable absorptions of the CCO NP-PI film, the passively Q-switched fiber laser expressed two stages with the increase of pump power for substantial performance enhancement. Reverse saturation absorption is observed to introduce appropriate cavity loss, which constructs effective pathways for promoting both the modulation depth and over threshold degree, as well as reducing the photon lifetime. In particular, our results realized the pulse duration and repetition rate compressing simultaneously for the first time. The second stage output laser exhibits a peak power of 1016 mW and a single pulse energy of 183 nJ, which are about 88 and 9 times higher than those of the first stage. Furthermore, the optical-optical conversion efficiency is up to 1270%. All of these can evidently demonstrate the importance of the appropriate cavity loss design for optimizing the Q-switched pulse laser output characteristics.

Differentiation of soft tissue benign and malignant peripheral nerve sheath tumors with magnetic resonance imaging.

PURPOSE: The objective of this study was to differentiate the magnetic resonance (MR) imaging appearance of benign peripheral nerve sheath tumors (PNSTs) from that of malignant PNSTs. MATERIALS AND METHODS: Twenty-six patients who underwent MR imaging and had a histologic diagnosis of benign (schwannoma, n=16; neurofibroma, n=1) or malignant (n=9) PNST were retrospectively reviewed. The size, location, shape, margin, and signal intensities of the tumors on precontrast and gadolinium-enhanced MR imaging were analyzed. In each patient, the presence or absence of split fat, target, and fascicular signs was determined. RESULTS: The mean size of the benign PNSTs (3.4 cm, S.D.=2.5 cm) was significantly smaller than that of the malignant tumors (8.2 cm, S.D.=3.1 cm) (P<.001). Seventeen (65.4%) of the 26 tumors were spindle shaped or ovoid (12 benign and 5 malignant tumors). Contiguity with specific nerves was identified in 15 (88.2%) of the 17 benign PNSTs but in none of the malignant tumors (P<.05). Well-defined margins were noted in all 17 benign PNSTs but in only 3 (33.3%) of the 9 malignant tumors (P<.001). Five (55.6%) of the 9 malignant PNSTs but none of the benign tumors showed signal intensity change in adjacent soft tissue (P<.05). There was no significant difference in signal intensity between the benign and malignant tumors on T(1)-weighted, T(2)-weighted, and contrast-enhanced MR images. The split fat and target signs were present more frequently in the benign PNSTs than in the malignant PNSTs (P<.05). CONCLUSIONS: Benign and malignant PNSTs are often spindle shaped. Recognition of contiguity with adjacent nerves, a well-defined margin, and the presence of the split fat sign may suggest benignity. Imaging features suggestive of malignancy can be a larger size and an infiltrative margin.

Gut microbiota correlates with fiber and apparent nutrients digestion in goose.

To explore the relationship among the level of fiber, gut microbiota, and nutritional substances, we applied the next generation sequencing technology for the identification of the composition and structure of microbiota in the gastrointestinal tract. In this study, a total of 25 phyla and 298 genera were identified from the gastrointestinal tract; Firmicutes, Bacteroidetes, and Proteobacteria were the predominant phyla. The ability of cecum in carbohydrate metabolism was significantly higher than that of the gizzard and ileum (P < 0.05). The bacterial community structure in various stages of the development of the cecum was different. In the different growth stages of cecum, the increase in the microbiota structure of the fiber level elevates the ability of carbon hydration. Second, the apparent metabolic rates of the other nutrients were affected by the fiber and period except for acid detergent fiber (P < 0.05); the apparent utilization rate of the nutrients increased with time. However, with the increase in the fiber level, the apparent utilization of nutrients was initially increased, followed by a decrease. Therefore, a correlation was established between the fiber level and gastrointestinal microbiota and apparent nutrient utilization rate of the 3 phyla. Our results suggest that the fiber level and growth stages could impact the composition of gut microbiota.

Complete mitochondrial genome of Nanjiang Yellow goat (Capra hircus).

Nanjiang Yellow goat (Capra hircus) is the first cultured mutton breed in China. In this study, the complete mitochondrial genome sequence of Nanjiang Yellow goat has been identified for the first time. The total length of the mitochondrial genome was 16,639 bp, with the base composition of 33.54% A, 26.05% C, 13.11% G and 27.30% T. It contained 37 genes (22 transfer RNA genes, 2 ribosomal RNA genes, and 13 protein-coding genes) and a major non-coding control region (D-loop). Most of the genes have ATG initiation codons, whereas ND2, ND3 and ND5 start with ATA. The complete mitochondrial genome sequence of Nanjiang Yellow goat provides an important data set for further estimation on the phylogeographic structure of domestic goats.

Effects of atrazine and chlorpyrifos on DNA methylation in the brain and gonad of the common carp.

DNA methylation is known to play an important role in the regulation of gene expression in animal. The purpose of the present study was to examine the effect of atrazine (ATR), chlorpyrifos (CPF) and combined ATR/CPF exposure on DNA methylation in the brain and gonad of common carp (Cyprinus carpio L.). The carp were sampled after a 40-d exposure to CPF and ATR, individually or in combination, followed by a 40-d recovery to measure the levels of global DNA methylation and the expression of methylation enzymes (DNA methyltransferases (DNMTs) and methylcytosine binding domain 2 (MBD2)) in the brain and gonad tissues. The results revealed that a significant global DNA hypomethylation in the common carp exposed to ATR, CPF and their mixture was observed compared to the control fish. The MBD2 mRNA expression was up-regulated in the brain and gonad of the common carp exposed to ATR, CPF and their mixture, in contrast, the DNMTs mRNA expression was down-regulated. The information regarding the effects of ATR and CPF on DNA methylation status generated in this study is important for pesticides toxicology evaluation. However, the effect of ATR and CPF on the methylation status of specific genes, as well as its detailed mechanism requires further investigation.

An in vivo swine study for xeno-grafts of calcium sulfate-based bone grafts with human dental pulp stem cells (hDPSCs).

The purpose of this in vivo study was to evaluate the effect of human dental pulp stem cells (hDPSCs) on various resorbable calcium sulfate/calcium phosphate bone grafts in bone regeneration. Granular particles of calcium sulfate dehydrate (CSD), α-calcium sulfate hemihydrate/amorphous calcium phosphate (α-CSH/ACP), and CSD/ß-tricalcium phosphates (ß-TCP) were prepared for in vitro dissolution and implantation test. The chemical compositions of specimen residues after dissolution test were characterized by XRD. The ratios of new bone formation for implanted grafts/hDPSCs were evaluated using mandible bony defect model of Lanyu pig. All the graft systems exhibited a similar two-stage dissolution behavior and phase transformation of poor crystalline HAp. Eight weeks post-operation, the addition of hDPSCs to various graft systems showed statistically significant increasing in the ratio of new bone formation (p<0.05). Null hypothesis of hDPSCs showing no scaffold dependence in bone regeneration was rejected. The results suggest that the addition of hDPSCs to calcium sulfate based xenografts could enhance the bone regeneration in the bony defect.

Alterations in activity and mRNA expression of acetylcholinesterase in the liver, kidney and gill of common carp exposed to atrazine and chlorpyrifos.

Insecticides and herbicides are widely used in modern agricultural production. The intensive use of insecticide chlorpyrifos (CPF) and herbicide atrazine (ATR) has resulted in serious environmental problems. Herein, we investigated alteration in activity and mRNA levels of AChE in the liver, kidney and gill from common carp after 40d exposure to CPF and ATR alone or in combination and 20d recovery treatment. Results indicated that activity and mRNA levels of AChE at all high-dose groups have been significantly decreased after CPF and ATR alone or ATR/CPF mixture exposure, and the changes were improved in the end of recovery tests in varying degrees, the activity and gene expression of AChE in the joint toxicity of ATR and CPF groups were significantly lower than that in the single toxicant group. Our study suggests that the decrease of AChE activity observed at all high-dose groups (CPF and ATR alone or in combination) may be directly related to a lower AChE expression, and the joint toxicity of ATR and CPF is higher than ATR and CPF alone.

Antioxidant response, CYP450 system, and histopathological changes in the liver of nitrobenzene-treated drakes.

Nitrobenzene (NB) has become an important pollutant in the environment, but its potential effects on non-target species such as drake remain unknown. In this study, we investigated the oxidative stress response, the CYP450 system and histopathological changes of the liver of NB-treated drakes for 40 d. Our results indicated that NB induced significant changes in antioxidant enzyme (SOD, CAT and GSH-Px) activities and the MDA content in the liver of the drakes. NB caused a condition-dependent increase in APND, EROD and ECOD isoenzyme activities and CYP450 content with increased exposure dose. Significant histological alternations were observed in the liver of NB-treated drakes and the pathological changes revealed tissue damage that was more severe with increasing of exposure dose. To our knowledge, this is the first study to report the chronic effects of NB on oxidative stress, the CYP450 system and histopathology in the drakes. These significant effects caused by NB reveal that these indices can be used as biomarker for monitoring NB as an environmental pollutant. Thus, future studies are needed to fully understand the exact mechanisms of these findings.

Accumulation, histopathological effects and response of biochemical markers in the spleens and head kidneys of common carp exposed to atrazine and chlorpyrifos.

This study assessed the impacts of atrazine (ATR), chlorpyrifos (CPF) and combined ATR/CPF exposure on the immune organs of common carp (Cyprinus carpio L.). The carp were sampled after a 40-d exposure to CPF and ATR, individually or in combination, followed by a 20-d recovery to measure the acid phosphatase (ACP), alkaline phosphatase (ALP), Na(+)/K(+)-ATPase, superoxide dismutase (SOD) and malondialdehyde (MDA) content. In addition, we also investigated histopathological changes and pesticide residues in the spleen and head kidney. The results revealed that the responses of SOD, MDA, ALP, ACP, and Na(+)/K(+)-ATPase to ATR, CPF and ATR/CPF combination exposure presented in a dose-dependent manner. The ACP activity and MDA content were significantly induced with increasing concentrations of ATR, CPF and combined ATR/CPF. However, the enzyme activities (SOD, ALP, and Na(+)/K(+)-ATPase) were reduced under exposure to increasing concentrations of these compounds. The accumulated amounts of ATR, CPF, and their metabolites in the spleens and head kidneys tissues exhibited dose-dependency. Pathological changes included tissue damage that was more severe with increasing exposure doses. SOD activity negatively correlated with MDA accumulation. The biochemical parameters exhibited sensitivity to ATR and CPF, suggesting that they may act as potential biomarkers for assessing the environmental ATR and CPF risk for carp.

A novel injectable chitosan/polyglutamate polyelectrolyte complex hydrogel with hydroxyapatite for soft-tissue augmentation.

This study demonstrated a chitosan (CS)/polyglutamate (PG) polyelectrolyte complex (PEC) hydrogel combined with spherical hydroxyapatite (HAp) particles as an injectable dermal filler for soft-tissue augmentation. The CS/PG PEC hydrogel with oppositely charged ionic cross-linking, a high gel content, and low degradation rate was introduced as a carrier to achieve high shape and volume stability. An MTT assay indicated that the CS/PG PEC had satisfactory cell biocompatibility. This PEC/HAp hydrogel showed good structural integrity in a PBS solution for up to 60 days. Clinical manageability was indexed by an injection force measurement through sterile 27-gauge needles using a texture analyzer. In an animal study, 0.2 mL of the PEC and PEC/hydroxyapatite (HAp) were implanted within the dorsal dermis of a swine ear. Injected tissue areas were biopsied 2 weeks, and 2 and 6 months after the injection. According to the histomorphometric results, the PEC and PEC/HAp groups showed percentages of retention of the maximum height of the cross-section of about 44% and 73% at 6 months. New collagen was observed in the central position indicating a possible collagenesis effect. These results suggest that this PEC/HAp system can be used as an alternative for soft-tissue augmentation.

Effects of a novel hydration accelerant on the biological and mechanical properties of white mineral trioxide aggregate.

INTRODUCTION: The objective of this study was to investigate the antibacterial, biocompatibility, and mechanical properties of mineral trioxide aggregate (MTA) set using a calcium lactate gluconate (CLG) solution. METHODS: ProRoot white MTA (WMTA) (Dentsply Tulsa Dental, Tulsa, OK) was used as the control group; MTA-like cement was prepared by mixing Portland cement/bismuth oxide/calcium sulfate (75/20/5) as the experiment group. A solution of 23.1 wt% CLG was used as a hydration accelerant and was compared with deionized water (DDW). Changes in pH values, antibacterial properties, in vitro cell viability, and diametral tensile strength (DTS) of the hydrated cements were assessed. RESULTS: Like WMTA, pH values for the MTA-like cement set using DDW and the CLG solution showed minor but statistically significant differences (P < .05). The antibacterial effects of hydrated specimens set by DDW and CLG against Streptococcus mutans assessed with an in vitro tube dilution test showed a significant difference in the early hydration time but no significant difference after 60 minutes (P > .05). A mouse osteoblastic cell (MC3T3-E1)-based MTT assay revealed that WMTA set using CLG had significantly higher cell viability than that set using DDW (P < .05). The DTS test for hydrated MTA-like cement with different liquids showed a significant difference on day 1 but no statistical difference on day 21. CONCLUSIONS: The results suggest that using a CLG solution as the hydration accelerant may enhance the biocompatibility but not compromise WMTA's antibacterial and mechanical properties.