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1.
Org Lett ; 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31793306

RESUMO

A gold(I) complex is reported. Interestingly, crystals of the gold(I) complex exhibit an excellent excitation wavelength-dependent emission effect at room temperature. Notably, a nearly pure white emission with Commission Internationale de L'Eclairage (CIE) 1931 chromaticity coordinates of (0.32, 0.33) is obtained upon excitation with 406 nm light.

2.
Cell Commun Signal ; 17(1): 163, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31823770

RESUMO

BACKGROUND: Recent evidence has suggested that the 1,25(OH)2D3/Vitamin D receptor (VDR) acts to suppress the immune response associated with systemic lupus erythematosus (SLE), a serious multisystem autoimmune disease. Hence, the aim of the current study was to investigate the mechanism by which 1,25-(OH)2D3/VDR influences SLE through regulating the Skp2/p27 signaling pathway. METHODS: Initially, the levels of 1,25(OH)2D3, VDR, Skp2, and p27 were measured in collected renal tissues and peripheral blood. Meanwhile, the levels of inflammatory factors, biochemical indicators (BUN, Cr, anti-nRNP IgG, anti-dsDNA IgG) and urinary protein levels were assayed in in VDRinsert and VDR-knockout mice in response to 1,25(OH)2D3 supplement. In addition, the distribution of splenic immune cells was observed in these mice. RESULTS: Among the SLE patients, the levels of 1,25(OH)2D3, VDR and p27 were reduced, while the levels of Skp2 were elevated. In addition, the levels of anti-nRNP IgG and anti-dsDNA IgG were increased, suggesting induction of inflammatory responses. Notably, 1,25(OH)2D3/VDR mice had lower concentrations of BUN and Cr, urinary protein levels, precipitation intensity of the immune complex and complement, as well as the levels of anti-nRNP IgG and anti-dsDNA IgG in SLE mice. Additionally, 1,25(OH)2D3 or VDR reduced the degree of the inflammatory response while acting to regulate the distribution of splenic immune cells. CONCLUSION: This study indicated that 1,25-(OH)2D3/VDR facilitated the recovery of SLE by downregulating Skp2 and upregulating p27 expression, suggesting the potential of 1,25-(OH)2D3/VDR as a promising target for SLE treatment.

3.
Org Lett ; 2019 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-31829020

RESUMO

We developed an electrochemically enabled dehydrogenative annulation reaction of amides and alkynes for the synthesis of antitumor polycyclic isoquinolinones through a double C-H activation route. No external oxidant is required in this reaction, and electricity is used for Ru catalyst circulation. The most remarkable feature of this reaction is the effective improvement of product regioselectivity under mild electrolytic conditions in comparison with previously set strong oxidant conditions.

4.
Sci Total Environ ; : 134532, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31785902

RESUMO

Flexible polyvinyl chloride (f-PVC) contains high content of plasticizers and chlorine. Improper treatment of waste f-PVC can easily lead to resource wasting and bring environmental risks. In this work, a novel strategy for resource recycling and dechlorination of waste f-PVC containing high content of di-(2-ethylhexyl) phthalate (DEHP) was developed by using low-temperature critical aqueous ammonia (LCA) process. The LCA treatment of waste DEHP-rich f-PVC (WDP) was performed at the temperature range of 200-400 °C with the ammonia concentration of 1%-5%. The results indicated that the LCA temperature had a significant effect on the chemical composition of decomposition products. High concentration of 2-ethyl-1-hexanol (86.12%), which is an important chemical feedstock and is derived from the decomposition of DEHP, could be obtained from WDP by the LCA process at 250 °C, and the concentration of 2-ethyl-1-hexanol decreased markedly with increasing the temperature. Benzaldehyde and acetophenone were generated when the temperature increased to 300 °C, and their concentrations increased with the rise of temperature. The increase of the ammonia concentration and the temperature could enhance the dechlorination efficiency of WDP. The dechlorination could reach 98.7% at 300 °C. This result showed that the LCA process was a promising and high-efficiency strategy for the sustainable management of WDP.

5.
J Neurosci Methods ; 331: 108538, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31794776

RESUMO

BACKGROUND: Functional near-infrared spectroscopy (fNIRS) was used to investigate spontaneous hemodynamic fluctuations in the bilateral temporal cortices for typically developing (TD) children and children with autism spectrum disorder (ASD). NEW METHOD: This paper proposed an approach to estimate the global time-varying behavior of brain activity through the measurement on change in first-order statistical properties directly from fNIRS time series. Then, a deep learning model combining the long-short term memory (LSTM) and convolutional neural network (CNN) was constructed based on the integration strategy with improved bagging algorithm, with the purpose to explore the potential patterns of temporal variation for ASD identification. RESULTS: Based on the theory of stationarity, analysis on the global time-varying behavior of hemodynamic fluctuations in oxy-hemoglobin (HbO2) and deoxy-hemoglobin (Hb) demonstrated that children with ASD showed weaker internal logic, but stronger memory and persistence to random shocks than TD children. Differentiating between ASD and TD with the proposed deep learning approach resulted in high accurate classification with sensitivity of 97.1 % and specificity of 94.3 %. COMPARISON WITH EXISTING METHODS: Using fNIRS time series of Hb from single optical channel, we achieved a better classification accuracy of 95.7 % that was about 8 % higher than previous methods with similar data. CONCLUSIONS: The characterization on time-varying behavior of brain activity holds promise for better understanding the underlying causes to ASD. And the deployed deep learning framework with an integration manner has the potential for screening children with risk of ASD.

6.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 37(6): 636-641, 2019 Dec 01.
Artigo em Chinês | MEDLINE | ID: mdl-31875443

RESUMO

OBJECTIVE: To investigate the influence of cuspal-coverage thickness on the stress distribution of all-ceramic onlay-restored premolars by using 3D finite element (FE) analysis and to provide references for the design of all-ceramic onlays for clinical application. METHODS: 3D FE models of all-ceramic onlays with three cuspal-coverage thicknesses (2, 3, and 4 mm) of endodontically treated maxillary premolar were constructed based on micro-CT images. Stress distributions in the onlay, adhesive resin cement layer, and dentin of models were analyzed under vertical load (600 N) and oblique load (200 N). RESULTS: When the cuspal-coverage thickness increased, the peak maximum principal stress value decreased inside the onlay but increased in the margin of the adhesive resin cement layer. In addition, stress concentration areas increased in the coronal residual dentin on the palatal side under oblique load. CONCLUSIONS: An increase in the cuspal-coverage thickness of all-ceramic onlays may reduce the risk of rupture of the restoration but may deteriorate the restoration and cause palatal dentin fracture.


Assuntos
Porcelana Dentária , Restaurações Intracoronárias , Dente Pré-Molar , Cerâmica , Resinas Compostas , Análise do Estresse Dentário , Análise de Elementos Finitos
7.
Am J Reprod Immunol ; : e13219, 2019 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-31872490

RESUMO

Antiphospholipid syndrome (APS) is one of the treatable causes for pregnant women with recurrent pregnancy loss (RPL). This review compares the efficacy of a few treatment interventions (low dose aspirin (LDA), aspirin plus low molecular weight heparin(LMWH) or unfractionated heparin (UFH)) in preventing complications during pregnancy and miscarriages for women with RPL and APS, and the potential differences in therapeutic effects of UFH and LMWH when combine with aspirin. We searched randomized controlled trials (RCTs) in MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials, and performed a systematic review and a Bayesian network meta-analysis (NMA). Finally, we found aspirin alone had a lower live birth rate compared to LMWH plus aspirin (OR=0.37; 95%CrI, 0.17, 0.71), and UFH plus aspirin showed a higher live birth rate than aspirin alone (OR= 2.63; 95%CrI, 1.04, 5.39) in NMA, Treating with UFH plus aspirin or LMWH plus aspirin did not have difference on live birth. Furthermore, LDA alone resulted in a lower birth weight compared to heparin plus aspirin, while higher birth weight was found when compared UFH plus aspirin to LMWH plus aspirin (MD= 895.40; 95%CrI, 817.40, 988.57) in NMA. Additionally, in women with RPL and APS and without a prior thrombosis, heparin plus aspirin improved birth weight but couldn't promote live birth rate compared to aspirin alone. In conclusion, heparin plus aspirin is recommended for women with RPL and APS. Notably UFH plus aspirin demonstrates the most significant therapeutic efficacy among these interventions in improving birth weight.

8.
Zhongguo Zhong Yao Za Zhi ; 44(22): 4793-4799, 2019 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-31872584

RESUMO

Polysaccharides are natural polymer compounds composed of monosaccharides,which are widely found in traditional Chinese medicines( TCM) and work as one of the important active ingredients in TCM. Modern pharmacological studies reported that TCM polysaccharides had many functions such as anti-tumor,immunologic enhancement,intestinal microenvironment regulation and anti-oxidation. At present,TCM polysaccharide preparations such as Astragalus polysaccharide injection,Ginseng polysaccharide injection and Poria cocos polysaccharide oral liquid have been widely applied for clinical use. Besides,Glycyrrhiza polysaccharide,Achyranthes bidentata polysaccharide,Acanthopanax senticosus polysaccharide and some other TCM polysaccharides also have received widespread attention and research because of their good biological activities. Meanwhile,more and more attention has been paid to the TCM polysaccharides and their preparations,illumination of mechanisms,and development of corresponding preparations which meet clinical standards. However,due to the complex structure of TCM polysaccharides,their structure analysis is difficult,with only a few reports on the stability and quality control of polysaccharides and their preparations. As a result,it will impede the development of new polysaccharide drugs and reduce the application value of polysaccharides. In order to provide an effective basis for the formulation development and quality control of TCM polysaccharides,the research progress on the stability of TCM polysaccharides and their preparations were reviewed in this paper from the classification of TCM polysaccharides,the existing application and the analytical method of TCM polysaccharides.


Assuntos
Medicamentos de Ervas Chinesas , Medicina Tradicional Chinesa , Polissacarídeos , Astrágalo (Planta) , Controle de Qualidade
9.
Asian J Androl ; 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31670279

RESUMO

The aim of this study was to investigate the role of seminal plasma miR-210-3p in the impairment of semen quality caused by varicocele. This study included 102 patients whose semen quality was normal when they were diagnosed with varicocele. A 2-year follow-up for included patients was performed, and they were divided into Group A (semen quality became abnormal) and Group B (semen quality remained normal) according to the results of semen analysis during the follow-up. Semen parameters and seminal plasma miR-210-3p expression were investigated by semen analysis and quantitative real-time polymerase chain reaction, respectively. In vitro experiments with GC-2 cells were performed to explore the role of miR-210-3p in spermatogenic cells. The results of quantitative real-time polymerase chain reaction showed that the level of seminal plasma miR-210-3p in Group A was higher than that in Group B both after 2-year follow-up and when they were diagnosed with varicocele (both P < 0.01). Apoptosis and proliferation assays showed that miR-210-3p induces apoptosis of spermatogenic cells by promoting caspase-3 activation. In conclusion, our study indicated that seminal plasma miR-210-3p induces spermatogenic cell apoptosis by activating caspase-3 in patients with varicocele. Seminal plasma miR-210-3p may be a potential biomarker for predicting impaired semen quality caused by varicocele.

10.
Artigo em Inglês | MEDLINE | ID: mdl-31718979

RESUMO

Identifying and detecting similar target cations through combining "turn on" and "turn off" fluorescence mechanism is effective and challenging. Now a new colorimetric and ON-OFF-ON fluorescent probe N'-((7-(diethylamino)-2-oxo-2H-chromen-3-yl)methylene)-3-hydroxy-2-naphthohydrazide (L) was reported, which could detect Cu2+ and Co2+ in phosphate buffered CH3CH2OH-H2O solvent system. With the assistance of glutathione and pH adjustment, a unique ON-OFF-ON fluorescence detection strategy could be achieved for distinguishing Cu2+ and Co2+. The emission of probe could recover from the L-Cu2+ and L-Co2+ system by addition of GSH or adjusting pH value to 4, respectively, which is due to the abolishment of paramagnetic Cu2+/Co2+. Based on fluorescence titration experiments, the limit of detection was determined as 3.84 × 10-9 M and 4.55 × 10-9 M for Cu2+ and Co2+, respectively. Meanwhile, the detection limit reached 6.21 × 10-8 M for Cu2+ and 6.96 × 10-8 M for Co2+ according to absorbance signal output. Fast recognition of Cu2+/Co2+ can be achieved by obvious color changes from green to colorless under UV light, as well as from yellow to orange-red in room light. The binding mode of L toward Cu2+ and Co2+ have been systematically studied by Job's plot analysis, ESI-MS, IR and density functional theory calculations. Most strikingly, further practical applications of the probe L in fluorescence imaging were investigated in MCF-7 cells and zebrafish due to its low cytotoxicity and good optical properties, suggesting that L could serve as a fluorescent sensor for tracking Cu2+ and Co2+in vivo.

11.
Chaos ; 29(11): 113126, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31779352

RESUMO

Driver fatigue is an important cause of traffic accidents, which has triggered great concern for detecting drivers' fatigue. Numerous methods have been proposed to fulfill this challenging task, including feature methods and machine learning methods. Recently, with the development of deep learning techniques, many studies achieved better results than traditional feature methods, and the combination of traditional methods and deep learning techniques gradually received attention. In this paper, we propose a recurrence network-based convolutional neural network (RN-CNN) method to detect fatigue driving. To be specific, we first conduct a simulated driving experiment to collect electroencephalogram (EEG) signals of subjects under alert state and fatigue state. Then, we construct the multiplex recurrence network (RN) from EEG signals to fuse information from the original time series. Finally, CNN is employed to extract and learn the features of a multiplex RN for realizing a classification task. The results indicate that the proposed RN-CNN method can achieve an average accuracy of 92.95%. To verify the effectiveness of our method, some existing competitive methods are compared with ours. The results show that our method outperforms the existing methods, which demonstrate the effect of the RN-CNN method.

12.
J Phys Condens Matter ; 32(9): 095101, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31722320

RESUMO

The mesoscopic collective motion of self-propelling active particle suspension confined in high aspect ratio two-dimensional micro-channel is numerically studied through coupled [Formula: see text] equation by considering background thermal fluctuation, inter-particle interaction, self-propulsion and micro-channel confinement. Both the self-propulsion and micro-channel confinement are the factors driving the system away from equilibrium and sustaining heterogeneous motion. In such system, the propulsion induced particle accumulation around the channel walls is a universal phenomenon with spatial heterogeneity, where large fraction of particles are caged inside the accumulated cluster with local oscillation coexisting with few fast propelling particles in the center region. Although the formation mechanism of the induced accumulation is well studied, post the cluster formation, how the cluster evolves and its dynamical properties is rarely discussed. Based on the merits of [Formula: see text] equation, the dynamical evolution of induced accumulation is revealed by particle trajectories. It is found that the induced accumulation can be dissociated through the slow re-orientation process of few jammed particles. By using the idea of force chain network, how the transverse confinement couples the transverse displacement with the longitudinal displacement is evidenced. It is further verified by the statistical measurement of correlation probability between transverse and longitudinal displacements. The suppressed displacements in both directions is the origin leading to the slow dynamics of cluster evolution. Temporally, within the orientational relaxation time, this system exhibits non-trivial anomalous diffusion under the competition between the counter effects of self-propulsion (enhanced diffusion) and micro-channel confinement (suppressed diffusion). Additionally, by considering the orientational coupling, the deep hysteresis of accumulation has been found even for very weak orientational coupling strength.

13.
Opt Lett ; 44(21): 5238-5241, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31674977

RESUMO

We demonstrate dual-Airy-beam-scanning-based volumetric two-photon microscopy (TPM) with depth-resolving capability. A pair of Airy beams with opposite acceleration is used as the excitation lights to sequentially illuminate the sample, and depth information can be resolved based on the deflection of the Airy beam. The depth-resolving range of the volumetric TPM is up to 32 µm. The advantages of the depth-resolved volumetric TPM are the depth-resolving capability over Bessel-beam-based TPM and less scanning times over traditional Gaussian-beam-based TPM. The depth-resolved volumetric TPM provides a promising fast imaging tool to study the dynamics in neural biology.

14.
Int J Paediatr Dent ; 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31680340

RESUMO

BACKGROUND: Obstructive sleep apnoea (OSA) affects many children, and adenotonsillar hypertrophy is the most common cause of paediatric OSA. AIM: Despite the growing treatment options, there is no comprehensive comparison of all interventions. We aimed to compare and rank the effectiveness of various treatments in a network meta-analysis. DESIGN: Literature was searched from inception to 13 May 2018 for paediatric OSA with adenotonsillar hypertrophy. The outcomes were the changes in apnoea-hypopnea index (AHI), oxyhaemoglobin desaturation index (ODI), and lowest arterial oxygen saturation (SaO2 ). Frequentist approach to network meta-analysis was used. Treatment hierarchy was summarized according to the surfaces under the cumulative ranking curves. RESULTS: Fourteen trials comprising 1064 paediatric OSA participants evaluating ten interventions (adenotonsillectomy, adenotonsillectomy + pharyngoplasty, adenotonsillotomy, antimicrobial therapy, steroids, leukotriene receptor antagonists [LTRAs], steroids + LTRAs, rapid maxillary expansion [RME], placebo, and no treatment) were identified for network meta-analysis. In terms of effectiveness in AHI reduction, surgical approach was still the most effective intervention than no treatment. RME was one of the most effective interventions to improve lowest SaO2 . No comparisons showed statistical significance in reducing ODI. CONCLUSIONS: Irrespective of the intervention used, complete resolution of OSA was not achieved in most trials.

15.
Opt Express ; 27(20): 27459-27476, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31684512

RESUMO

The ray-optics (RO) model is a reasonable method to calculate optical force in geometrical optics regime. However, the RO model fails to calculate the optical force produced by diffractive optical field and other arbitrary structured light beams. We propose the Fourier ray (FR) method to calculate the optical force for arbitrary incident beams. Combining the Fourier optics and the geometrical optics, the FRs are defined as rays that inlay on the plane waves weighted by the Fourier angular spectrum of the incident beam. According to traditional RO model and FR method, we can analyze optical forces on a microsphere immersed in various beams. To validate the FR method, forces of the fundamental Gaussian beam and Airy beam are respectively calculated and compared with traditional method. In addition, optical forces in three arbitrary structured light beams are demonstrated as well. Our simulations show that the FR method is able to evaluate the optical forces generated by diffractive optical field and complex structured light beams, and give a solid prediction of their trapping performances. In RO regime, the Fourier ray method is a universal method to predict the interaction between bead and complex optical field.

16.
Int J Mol Sci ; 20(22)2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31739640

RESUMO

d-tagatose, a monosaccharide as well as a dietary supplement, has been reported as having a wide range of applicability in the food industry, however, the prebiotic activity, anticonstipation effects, and related mechanisms are still unclear. In this study, using the loperamide-induced constipation Kunming mice as the animal model, the effects of d-tagatose for the prevention of constipation were evaluated by gastrointestinal transit experiment and defecation experiment. Furthermore, the underlying mechanism was clarified by evaluating the change of the biochemical indicators and analyzing 16S rRNA amplicon of gut microbiota among the different mice groups. The results showed that the gastrointestinal transit rate, fecal number, and weight in six hours were significantly enhanced after the administration of d-tagatose. In addition, d-tagatose significantly increased the serum levels of acetylcholine (Ach) and substance P (SP), whereas the serum levels of nitric oxide (NO) were significantly decreased. Moreover, the 16S rRNA sequencing analysis revealed that the changes in the gut microbiota caused by constipation were restored by d-tagatose treatment. In conclusion, this study indicated that the administration of d-tagatose as a dietary supplement can effectively prevent and relieve constipation in Kunming mice, and it is a promising prebiotic candidate with constipation-relieving properties.

17.
Front Physiol ; 10: 1225, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31607953

RESUMO

Mitophagy plays a key role in cleaning damaged and depolarized mitochondria to maintain cellular homeostasis and viability. Although it was originally found in neurodegenerative diseases, mitophagy is reported to play an important role in acute kidney injury. PINK1 and Parkin are key molecules in mitophagy pathway. Here, we used PINK1 knockout rats to examine the role of PINK1/Parkin-mediated mitophagy in cisplatin nephrotoxicity. After cisplatin treatment, PINK1 knockout rats showed lower plasma creatinine and less tubular damage when compared with wild-type rats. Meanwhile, mitophagy indicated by autophagosome formation and LC3B-II accumulation was also attenuated in PINK1 knockout rats. Renal expression of PINK1 and Parkin were down-regulated while BNIP3L was up-regulated by cisplatin treatment, indicating a major role of BNIP3/BNIP3L pathway in cisplatin-induced mitophagy. Transmission electron microscopy showed that PINK1 deficiency inhibited cisplatin-induced mitochondrial fragmentation indicating an involvement of mitochondrial fusion and fission. Renal expression of mitochondrial dynamics related proteins including Fis1, Drp1, Mfn1, Mfn2, and Opa1 were checked by real-time PCR and western blots. The results showed PINK1 deficiency distinctly prevented cisplatin-induced up-regulation of DRP1. Finally, PINK1 deficiency alleviated cisplatin-induced tubular apoptosis indicated by TUNEL assay as well as the expression of caspase3 and cleaved caspase3. Together, these results suggested PINK1 deficiency ameliorated cisplatin-induced acute kidney injury in rats, possibly via inhibiting DRP1-mediated mitochondrial fission and excessive mitophagy.

18.
Clinicoecon Outcomes Res ; 11: 539-550, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31564930

RESUMO

Background: Little is known about the patient-reported and economic burdens of postherpetic neuralgia (PHN) among China's urban population. Methods: This noninterventional study was conducted among adults ≥40 years with PHN who were seeking medical care at eight urban hospitals in China. At one study site, patients completed a questionnaire evaluating the patient-reported disease burden (N=185). The questionnaire consisted of validated patient-reported outcomes including the Brief Pain Inventory (BPI), 5-dimension, 3-level EuroQol (EQ-5D-3L), Medical Outcomes Study Sleep Scale, and Work Productivity and Activity Impairment Questionnaire for Specific Health Problems. Questions on non-pharmacologic therapy and out-of-pocket (OOP) expenses were also included. At all study sites, physicians (N=100) completed a structured review of patient charts (N=828), which was used to derive health care resource utilization and associated costs from the societal perspective. Annual costs in Chinese Yuan Renminbi (RMB) for the year 2016 were converted to US dollars (US$). Results: Patients (N=185, mean age 63.0 years, 53.5% female) reported pain of moderate severity (mean BPI score 4.6); poor sleep quantity (average of 5.3 hrs per night) and quality; and poorer health status on the EQ-5D-3L relative to the general Chinese population. Respondents also reported average annual OOP costs of RMB 16,873 (US$2541) per patient, mainly for prescription PHN medications (RMB 8990 [US$1354]). Substantial work impairment among employed individuals resulted in annual indirect costs of RMB 28,025 (US$4221). In the chart review, physicians reported that patients (N=828) had substantial health resource utilization, especially office visits; 98% had all-cause and 95% had PHN-related office visits. Total annual direct medical costs were RMB 10,002 (US$1507), mostly driven by hospitalizations (RMB 8781 [US$1323]). Conclusion: In urban China, PHN is associated with a patient-reported burden, affecting sleep, quality-of-life, and daily activities including work impairment, and an economic burden resulting from direct medical costs and indirect costs due to lost productivity. These burdens suggest the need for appropriate prevention and management of PHN.

19.
Opt Lett ; 44(19): 4813-4816, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31568449

RESUMO

We unveil a new type of dissipative soliton behavior in a net-normal-dispersion bidirectional ultrafast fiber laser. That is, the bidirectional dissipative solitons will always reveal similar spectral and temporal characteristics through common gain and loss modulation, even if the transient instability is involved. The behavioral similarity enables us to accurately design the soliton patterns by introducing seed pulses through loss modulation. As a proof-of-concept application, the precise and flexible manipulation of multi-soliton patterns is demonstrated. These findings will shed new insights into the complex dissipative soliton dynamics and benefit the design of ultrafast lasers with desirable soliton patterns for practical applications.

20.
Environ Pollut ; : 113417, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31662269

RESUMO

A facile method was developed to fabricate porous tube-like ZnS by sulfurizing rod-like ZIF-L with thioacetamide (TAA) at different durations and the formation mechanism of the porous tube-like ZnS was discussed in detail. The series of sulfide products (ZS-X) were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), solid-state nuclear magnetic resonance spectroscopy (SSNMR), transmission electron microscopy (TEM), UV-visible diffuse-reflectance spectroscopy (UV-vis DRS). The photocatalytic performances of ZS-X toward Cr(VI) reduction and organic pollutant degradation were explored. It was discovered that ZS-3 (porous tube-like ZnS) exhibited excellent activities under UV light and displayed good reusability and stability after several experimental cycles. In addition, Cr(VI) reduction and organic pollutant degradation were investigated under different pH values and existence of different foreign ions. The photocatalytic activities of ZS-3 were tested toward the matrix of Cr(VI) and reactive red X-3B. The mechanism was proposed and verified by both electrochemical analysis and electron spin resonance (ESR) measurement.

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