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1.
East Asian Arch Psychiatry ; 33(2): 37-43, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37400226

ABSTRACT

INTRODUCTION: Community treatment orders (CTOs) enable patients to actively engage in mental health services while being supervised in the community outside the hospital setting. However, the efficacy of CTOs remains controversial in terms of mental health services usage or service contacts, emergency visits, and violence. METHODS: The databases PsychINFO, Embase, and Medline were searched on 11 March 2022 by 2 independent reviewers through the Covidence website (www.covidence.org). Randomised or non-randomised case-control studies and pre-post studies were included if they examine the effect of CTOs on service contacts, emergency visits, and violence in individuals with mental illnesses by comparing with control groups or pre-CTO conditions. Conflicts were resolved by consultation of the third independent reviewer. RESULTS: Sixteen studies provided sufficient data in the target outcome measures and were included in analysis. Variability in the risk of bias was high among studies. Meta-analyses were conducted separately for case-control studies and pre-post studies. For service contacts, a total of 11 studies with 66,192 patients reported changes in the number of service contacts under CTOs. In 6 case-control studies, a small non-significant increase in service contacts was observed in those under CTOs (Hedge's g = 0.241, z = 1.535, p = 0.13). In 5 pre-post studies, a large and significant increase in service contacts was noted after CTOs (Hedge's g = 0.830, z = 5.056, p < 0.001). For emergency visits, a total of 6 studies with 930 patients reported changes in the number of emergency visits under CTOs. In 2 case-control studies, a small non-significant increase in emergency visits was noted in those under CTOs (Hedge's g = -0.196, z = -1.567, p = 0.117). In 4 pre-post studies, a small significant decrease in emergency visits was noted after CTOs (Hedge's g = 0.553, z = 3.101, p = 0.002). For violence, a total of 2 pre-post studies reported a moderate significant reduction in violence after CTOs (Hedge's g = 0.482, z = 5.173, p < 0.001). CONCLUSION: Case-control studies showed inconclusive evidence, but pre-post studies showed significant effects of CTOs in promoting service contacts and reducing emergency visits and violence. Future studies on cost-effectiveness analysis and qualitative analysis for specific populations with various cultures and backgrounds are warranted.


Subject(s)
Community Mental Health Services , Mental Disorders , Mental Health Services , Humans , Mental Disorders/therapy , Violence/prevention & control , Emergency Service, Hospital
2.
Opt Express ; 29(8): 12590-12598, 2021 Apr 12.
Article in English | MEDLINE | ID: mdl-33985013

ABSTRACT

We report on the experimental observation of coexistence of solitons and polarization domains, as well as features of soliton collision with polarization domain walls (or kink solitons) in a single mode fiber laser. Depending on the sign of cavity dispersion, either bright or dark solitons have been formed in our fiber laser. Under suitable laser operation conditions, they could even coexist with polarization domains and collide with the domain walls. We show experimental evidence of both the elastic and inelastic soliton collisions with the domain wall solitons. Some interesting features of soliton interaction with polarization domains in a fiber laser are also firstly revealed.

3.
Opt Lett ; 46(5): 1105-1108, 2021 Mar 01.
Article in English | MEDLINE | ID: mdl-33649668

ABSTRACT

We report, to the best of our knowledge, the first experimental observation of coexistence of scalar dark and bright solitons in a fiber laser operating in the near zero-dispersion regime. We show that because of the incoherent cross coupling, under suitable conditions a bright soliton formed in the net anomalous cavity dispersion regime could bind with a dark soliton formed in the net normal cavity dispersion regime in a fiber laser. The properties of the dark and bright solitons, as well as their bound states, are experimentally investigated. The numerical simulations based on the coupled Ginzburg-Landau equations have reproduced the experimental results well.

5.
Opt Lett ; 45(23): 6563-6566, 2020 Dec 01.
Article in English | MEDLINE | ID: mdl-33258862

ABSTRACT

We report the first experimental observation of coherently coupled black-black solitons in a quasi-isotropic cavity fiber laser with normal cavity dispersion. The properties of the vector solitons accord well with the theoretical predictions based on the coherently coupled nonlinear Schrödinger equations. Numerical studies and experimental results clearly confirmed the existence of the highly robust vector black solitons in the fiber laser system.

6.
Opt Express ; 27(13): 18311-18317, 2019 Jun 24.
Article in English | MEDLINE | ID: mdl-31252776

ABSTRACT

We report experimental observation of incoherently coupled dark-bright vector solitons in single-mode fibers. Properties of the vector solitons accord well with those predicted by the respective systems of incoherently coupled nonlinear Schrödinger equations. To our knowledge, this is the first experimental observation of temporal incoherently coupled dark-bright solitons in single-mode fibers.

7.
Opt Lett ; 44(9): 2185-2188, 2019 May 01.
Article in English | MEDLINE | ID: mdl-31042179

ABSTRACT

We report the experimental observation of coherently coupled dark-bright vector solitons in single mode fiber lasers with either normal or anomalous cavity dispersion. The properties of these vector solitons were found to agree well with theoretical predictions based on the coherently coupled nonlinear Schrödinger equations. The experimental results clearly confirmed the existence of a fundamentally new form of optical solitons in coupled nonlinear systems.

8.
Opt Express ; 24(2): 1814-22, 2016 Jan 25.
Article in English | MEDLINE | ID: mdl-26832559

ABSTRACT

We report on the experimental observation of vector and bound vector solitons in a fiber laser passively mode locked by graphene. Localized interactions between vector solitons, vector soliton with bound vector solitons, and vector soliton with a bunch of vector solitons are experimentally investigated. We show that depending on the soliton interactions, various stable and dynamic multiple vector soliton states could be formed.

9.
Appl Opt ; 54(1): 71-5, 2015 Jan 01.
Article in English | MEDLINE | ID: mdl-25967008

ABSTRACT

We report results of numerical simulations on the various initial conditions for dark soliton generation in an all-normal-dispersion fiber laser. All the dark solitons generated are odd dark solitons. Differently from the dark soliton generation in fibers, where an arbitrary dip could evolve into a dark soliton, it is found that the dark soliton can originate only from an initial dip with a certain parameter requirement. A bright pulse with either a hyperbolic secant square, Gaussian, or Lorentz profile can be developed into a dark soliton, provided that the parameters of the initial bright pulse are selected. Dark solitons can be generated in fiber lasers only if there is a phase jump, and this phase jump can be maintained and evolve to π during the pulse evolution.

10.
Opt Express ; 23(9): 11183-94, 2015 May 04.
Article in English | MEDLINE | ID: mdl-25969214

ABSTRACT

Black phosphorous (BP), the most thermodynamically stable allotrope of phosphorus, is a high-mobility layered semiconductor with direct band-gap determined by the number of layers from 0.3 eV (bulk) to 2.0 eV (single layer). Therefore, BP is considered as a natural candidate for broadband optical applications, particularly in the infrared (IR) and mid-IR part of the spectrum. The strong light-matter interaction, narrow direct band-gap, and wide range of tunable optical response make BP as a promising nonlinear optical material, particularly with great potentials for infrared and mid-infrared opto-electronics. Herein, we experimentally verified its broadband and enhanced saturable absorption of multi-layer BP (with a thickness of ~10 nm) by wide-band Z-scan measurement technique, and anticipated that multi-layer BPs could be developed as another new type of two-dimensional saturable absorber with operation bandwidth ranging from the visible (400 nm) towards mid-IR (at least 1930 nm). Our results might suggest that ultra-thin multi-layer BP films could be potentially developed as broadband ultra-fast photonics devices, such as passive Q-switcher, mode-locker, optical switcher etc.

11.
Opt Lett ; 39(12): 3484-7, 2014 Jun 15.
Article in English | MEDLINE | ID: mdl-24978517

ABSTRACT

We report on an ultrahigh repetition rate dark soliton fiber laser. We show both numerically and experimentally that by taking advantage of the cavity self-induced modulation instability and the dark soliton formation in a net normal dispersion cavity fiber laser, stable ultrahigh repetition rate dark soliton trains can be formed in a dispersion-managed cavity fiber laser. Stable dark soliton trains with a repetition rate as high as ∼280 GHz have been generated in our experiment. Numerical simulations have shown that the effective gain bandwidth limitation plays an important role on the stabilization of the formed dark solitons in the laser.

12.
Opt Express ; 22(6): 7249-60, 2014 Mar 24.
Article in English | MEDLINE | ID: mdl-24664073

ABSTRACT

The nonlinear optical property of few-layered MoS2 nanoplatelets synthesized by the hydrothermal exfoliation method was investigated from the visible to the near-infrared band using lasers. Both open-aperture Z-scan and balanced-detector measurement techniques were used to demonstrate the broadband saturable absorption property of few-layered MoS2. To explore its potential applications in ultrafast photonics, we fabricated a passive mode locker for ytterbium-doped fibre laser by depositing few-layered MoS2 onto the end facet of optical fiber by means of an optical trapping approach. Our laser experiment shows that few-layer MoS2-based mode locker allows for the generation of stable mode-locked laser pulse, centered at 1054.3 nm, with a 3-dB spectral bandwidth of 2.7 nm and a pulse duration of 800 ps. Our finding suggests that few-layered MoS2 nanoplatelets can be useful nonlinear optical material for laser photonics devices, such as passive laser mode locker, Q-switcher, optical limiter, optical switcher and so on.

13.
Genet Mol Res ; 13(2): 2827-39, 2014 Jan 22.
Article in English | MEDLINE | ID: mdl-24535906

ABSTRACT

Exogenous gibberellins (GAs) are widely applied to increase crop yields, with knowledge about the physiological functioning and biochemistry mechanisms of these phytohormones improving; however, information remains limited about the effect of GAs on seed filling. In this study, the siliques (containing the seeds) of oilseed rape (Brassica napus L.) were treated with GA3 at 3 stages of seed filling. We confirmed that GA3 regulates the deposition of storage reserves in developing seeds. The percentage of crude fat in the seeds increased during the early stage, but remained stable during the middle and late stages. In comparison, the percentage of total protein decreased during the early and middle stages, but significantly increased during the late stage. In addition, Q-PCR was employed to analyze the expression level of related genes in response to GA3. It was found that the expression of WRI and ABI3 transcription factors corresponded to crude fat content and total protein content, respectively. The expression of storage reserve related genes DGAT, MCAT, SUC2, and GPT was consistent with crude fat content, whereas the expression of Napin corresponded to total protein content. The results of this study indicate that exogenous GA3 has a different effect on storage reserve deposition in seed during different stages of seed filling, and the effect might be achieved via changing the expression of related genes.


Subject(s)
Brassica napus/growth & development , Gibberellins/administration & dosage , Seeds/growth & development , Brassica napus/drug effects , Fatty Acids/metabolism , Gene Expression Regulation, Plant/drug effects , Plant Proteins/biosynthesis , Seeds/drug effects , Seeds/genetics
14.
East Asian Arch Psychiatry ; 23(2): 37-44, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23807628

ABSTRACT

OBJECTIVE. Antisocial personality disorder (ASPD) is a risk factor for violence and is associated with poor treatment response when it is a co-morbid condition with substance abuse. It is an under-recognised clinical entity in the local Hong Kong setting, for which there are only a few available Chinese-language diagnostic instruments. None has been tested for its psychometric properties in the Cantonese-speaking population in Hong Kong. This study therefore aimed to assess the reliability and validity of the Chinese version of the ASPD subscale of the Structured Clinical Interview for the DSM-IV Axis II Disorders (SCID-II) in Hong Kong Chinese. METHODS. This assessment tool was modified according to dialectal differences between Mainland China and Hong Kong. Inpatients in Castle Peak Hospital, Hong Kong, who were designated for priority follow-up based on their assessed propensity for violence and who fulfilled the inclusion criteria for the study, were recruited. To assess the level of agreement, best-estimate diagnosis made by a multidisciplinary team was compared with diagnostic status determined by the SCID-II ASPD subscale. The internal consistency, sensitivity, and specificity of the subscale were also calculated. RESULTS. The internal consistency of the subscale was acceptable at 0.79, whereas the test-retest reliability and inter-rater reliability showed an excellent and good agreement of 0.90 and 0.86, respectively. Best-estimate clinical diagnosis-SCID diagnosis agreement was acceptable at 0.76. The sensitivity, specificity, positive and negative predictive values were 0.91, 0.86, 0.83, and 0.93, respectively. CONCLUSION. The Chinese version of the SCID-II ASPD subscale is reliable and valid for diagnosing ASPD in a Cantonese-speaking clinical population.


Subject(s)
Antisocial Personality Disorder/diagnosis , Asian People/psychology , Diagnostic and Statistical Manual of Mental Disorders , Adult , Female , Hong Kong , Humans , Male , Middle Aged , Observer Variation , Predictive Value of Tests , Reproducibility of Results , Sensitivity and Specificity
15.
Opt Lett ; 37(11): 2085-7, 2012 Jun 01.
Article in English | MEDLINE | ID: mdl-22660129

ABSTRACT

We experimentally demonstrated a passively mode-locked femtosecond laser by using a graphene-based saturable absorber mirror (graphene SAM) in the spectral region of 2 µm. The graphene SAM was fabricated by transferring chemical-vapor-deposited, high-quality, and large-area graphene on a highly reflective plane mirror. Stable mode-locked laser pulses as short as 729 fs were obtained with a repetition rate of 98.7 MHz and an average output power of 60.2 mW at 2018 nm.

16.
Opt Lett ; 37(6): 1076-8, 2012 Mar 15.
Article in English | MEDLINE | ID: mdl-22446230

ABSTRACT

We have experimentally demonstrated a highly efficient diode-pumped Tm:YAG ceramic laser operating at 2 µm wavelength. The maximum output power of 6.05 W was realized with a slope efficiency as high as 65%. As far as we know, it is the highest slope efficiency reported for Tm:YAG ceramic laser. The wavelength tuning experiment of Tm:YAG ceramic laser was carried out and the results suggest that Tm:YAG ceramic laser could operate simultaneously at multiple wavelengths in a wide range of 1884-2017 nm.


Subject(s)
Ceramics/chemistry , Lasers, Solid-State , Absorption , Spectrometry, Fluorescence
17.
Opt Lett ; 36(24): 4767-9, 2011 Dec 15.
Article in English | MEDLINE | ID: mdl-22179877

ABSTRACT

We report on the efficient operation of a high-power erbium-doped polycrystalline Er:YAG ceramic laser at 1617 nm resonantly pumped by a high-power 1532 nm Er,Yb fiber laser. Lasing characteristics of Er:YAG ceramics with different Er3+ concentrations are evaluated and compared. With an output coupler of 15% transmission and 0.5 at. % Er3+-doped YAG ceramic as the gain media, the laser generates 14 W of output power at 1617 nm for 28.8 W of incident pump power at 1532 nm, corresponding to a slope efficiency with respect to incident pump power of 51.7%.

18.
Opt Lett ; 36(19): 3888-90, 2011 Oct 01.
Article in English | MEDLINE | ID: mdl-21964131

ABSTRACT

We report to our knowledge a diode-pumped passively mode-locked Yb:CaNb(2)O(6) (Yb:CN) laser for the first time. Both CW and passive mode-locking operation of the laser are experimentally investigated. A maximum CW output power of 1.4 W with a slope efficiency of 20% is obtained on a 7 mm long 1.5 at.% Yb:CN crystal, while stable passive mode-locking with a commercial semiconductor saturable absorption mirror (SESAM) was achieved on a 3 mm long 3 at.% Yb:CN crystal. The mode-locked pulses have pulse width of 251 fs and an average output power of 44 mW at 1038 nm.

19.
Opt Express ; 19(19): 18495-500, 2011 Sep 12.
Article in English | MEDLINE | ID: mdl-21935218

ABSTRACT

Operation of an end-pumped Yb³âº:CaYAlO4 laser operating in the positive dispersion regime is experimentally investigated. The laser emitted strongly chirped pulses with extremely steep spectral edges, resembling the characteristics of dissipative solitons observed in fiber lasers. The results show that dissipative soliton emission constitutes another operating regime for mode locked Yb³âº-doped solid state lasers, which can be explored for the generation of stable large energy femtosecond pulses.

20.
Opt Lett ; 36(17): 3395-7, 2011 Sep 01.
Article in English | MEDLINE | ID: mdl-21886222

ABSTRACT

A new (to our knowledge) ultrashort laser pulse irradiation regime that allows us to directly modify and increase the refractive index of rare earth doped YAG polycrystalline ceramics has been identified. Single-mode buried channel waveguides in both Ho:YAG and Er:YAG ceramics at the near-IR wavelengths of 1.55 µm and 1.95 µm are demonstrated by fabricating positive square step-index cores. Minimum propagation losses of 1.5 dB cm(-1) at a 1.51 µm wavelength have been preliminarily obtained. Confocal microluminescence mapping reveals that the increased refractive index regions retain the near-IR spectral properties of Er3+ ions in the YAG crystalline matrix.

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