208 W single-frequency 1064 nm laser based on a single-crystal fiber master-oscillator power amplifier.

High-power all-solid-state continuous-wave (CW) single-frequency laser with high linear polarization is a significant source for quantum optics and precision measurement. In this Letter, a high-power linearly polarized CW single-frequency laser based on the single-crystal fiber (SCF) master-oscillator power amplifier (MOPA) is presented, in which a homemade 140 W low-noise CW single-frequency laser and a Nd:YAG SCF are firstly employed as the seed laser and the medium of the MOPA, respectively. The mode-matching between the pump laser propagated with waveguide form and the freely propagated seed laser is optimized by considering the influence of the degradations of the polarization and the beam quality. Finally, when the incident powers of the pump and seed lasers are 262.6 W and 126.3 W, respectively, the seed waist radius is optimized to 200 µm. In this case, the output power of the linearly polarized laser reaches up to 208 W, which is the highest output power, to the best of our knowledge. The presented results provide a good reference for implementing a high power and high degree of the polarization and good beam quality laser based on the SCF MOPA.

Self-mode-matching compact low-noise all-solid-state continuous wave single-frequency laser with output power of 140 W.

The high power all-solid-state continuous wave single-frequency laser is a significant source for science and application due to good beam quality and low noise. However, the output power of the laser is usually restricted by the harmful thermal lens effect of the solid gain medium. To address this issue, we develop a self-mode-matching compact all-solid-state laser with a symmetrical ring resonator in which four end-pumped Nd:YVO4 laser crystals are used for both laser gain media and mode-matching elements. With this ingenious design, the thermal lens effect of every laser crystal can be controlled and the dynamic of the designed laser including the stability range and the beam waist sizes at crystals can be manipulated only by adjusting the pump power used on each laser gain medium. Under an appropriate combination of pump powers on four crystals, self-mode-matching in a resonator is realized. A stable CW single-frequency at 1064 nm with 140-W power, 102-kHz linewidth, and low intensity noise is obtained. The presented design paves an effective way to further scale-up the output power of a compact laser by employing more pieces of gain media.

Performance Improvement of Single-Frequency CW Laser Using a Temperature Controller Based on Machine Learning.

The performance improvement of an all-solid-state single-frequency continuous-wave (CW) laser with high output power is presented in this paper, which is implemented by employing a temperature control system based on machine learning to control the temperature of laser elements including gain crystal, laser diode and so on. Because the developed temperature controller based on machine learning combines the back propagation (BP) neural network algorithm with the proportion-integration-differentiation (PID) control algorithm, the parameters of the PID are adaptive with the variation of the environment. As a result, the control speeds and control abilities of the temperatures of the elements are dramatically enhanced. In this case, the output characteristic and the adaptability to the environment as well as the stability of the single-frequency CW laser are also improved greatly.

A Review of the High-Power All-Solid-State Single-Frequency Continuous-Wave Laser.

High-power all-solid-state single-frequency continuous-wave (CW) lasers have been applied in basic research such as atomic physics, precision measurement, radar and laser guidance, as well as defense and military fields owing to their intrinsic advantages of high beam quality, low noise, narrow linewidth, and high coherence. With the rapid developments of sciences and technologies, the traditional single-frequency lasers cannot meet the development needs of emerging science and technology such as quantum technology, quantum measurement and quantum optics. After long-term efforts and technical research, a novel theory and technology was proposed and developed for improving the whole performance of high-power all-solid-state single-frequency CW lasers, which was implemented by actively introducing a nonlinear optical loss and controlling the stimulated emission rate (SER) in the laser resonator. As a result, the output power, power and frequency stabilities, tuning range and intensity noise of the single-frequency lasers were effectively enhanced.

Image reconstruction through a multimode fiber with a simple neural network architecture.

Multimode fibers (MMFs) have the potential to carry complex images for endoscopy and related applications, but decoding the complex speckle patterns produced by mode-mixing and modal dispersion in MMFs is a serious challenge. Several groups have recently shown that convolutional neural networks (CNNs) can be trained to perform high-fidelity MMF image reconstruction. We find that a considerably simpler neural network architecture, the single hidden layer dense neural network, performs at least as well as previously-used CNNs in terms of image reconstruction fidelity, and is superior in terms of training time and computing resources required. The trained networks can accurately reconstruct MMF images collected over a week after the cessation of the training set, with the dense network performing as well as the CNN over the entire period.

Influence of the pump scheme on the output power and the intensity noise of a single-frequency continuous-wave laser.

The influence of the pump scheme on the intensity noise of the single-frequency continuous-wave (CW) laser is investigated in this paper, which is implemented in a single-frequency CW Nd:YVO4 1064 nm laser by comparing the traditional 808 nm pumping scheme (TPS) to the direct 888 nm pumping scheme (DPS). Under the conditions that the lasers with TPS and DPS have the same cavity structure and the cavity mirrors, as well as the same operation state including the thermal lens of the laser crystals and the mode-matching between the pump laser mode and the laser cavity mode at the laser crystals, the output power of the laser with DPS is up-to 32.0 W, which is far higher than that of 21.1 W for the laser with TPS. However, the intensity noise of the DPS laser including resonant relaxation oscillation (RRO) frequency of 809 kHz, RRO peak amplitude of 31.6 dB/Hz above the shot noise level (SNL) and the SNL cutoff frequency of 4.2 MHz, respectively, is also higher than that of 606 kHz, 20.4 dB/Hz and 2.4 MHz for the TPS laser. After further analyses, we find that the laser crystal with high doping concentration and long optical length is employed for DPS laser in order to improve the pump laser absorption efficiency, which can simultaneously increase the dipole coupling between the active atoms and the laser cavity, and then results in a high RRO frequency with a large amplitude peak as well as a high SNL cutoff frequency of the laser.

[Long-term efficacy and safety of electroacupuncture on improving MMSE in patients with Alzheimer's disease].

OBJECTIVE: To observe the efficacy and safety of electroacupuncture (EA) on improving mini-mental state examination (MMSE) in patients with Alzheimer's disease (AD), and to evaluate the efficacy during follow-up visit. METHODS: Forty patients were randomly divided into a treatment group and a control group, 20 patients in each one (3 patients dropped off in the treatment group and 4 patients in the control group). The patients in the treatment group were treated with acupuncture at Baihui (GV 20), Fengfu (GV 16), Shenting (GV 24), Taiyang (EX-HN 5), Shangyintang (Extra 3) and Dazhong (KI 14); besides, EA was applied at Taiyang (EX-HN 5), Baihui (GV 20) and Shenting (GV 24) with dilatational wave, 10 Hz/50 Hz in frequency, 0.5 to 5.0 mA in intensity, once every two days, three treatments per week. The patients in the control group were treated with oral administration of donepezil hydrochloride tablets, once a day, taken before sleep. The treatment was given for 12 weeks in the two groups. The MMSE was evaluated before treatment, 12 weeks±3 days into treatment, and 24 weeks±7 days after treatment, respectively. RESULTS: The difference of total score of MMSE before and 12 weeks±3 days into treatment was not significant between the two groups (P>0.05); the total score of MMSE after treatment was higher than that before treatment (both P<0.05); compared before treatment, the short-term memory score was increased in the treatment group (P<0.05), and the increasing range was superior to that in the control group (P<0.05). Compared before treatment, the total score of MMSE in the two groups were reduced 24 weeks ±7 days after treatment (both P<0.05), and the reduction in the treatment group was less than that in the control group (P<0.05); the differences of short-term memory score before and after treatment was significant between the two groups (P<0.05). No adverse reaction occurred in the two groups. CONCLUSION: The effect of EA on improving MMSE in patients with AD is similar to donepezil supported by evidence-based medicine. The effect of EA may have a certain continuous effect, and may have advantages in instantaneous memory. In addition, the EA is safe.

Intensity noise suppression of a high-power single-frequency CW laser by controlling the stimulated emission rate.

The intensity noise of a high-power single-frequency continuous-wave (CW) laser is very harmful for applications in precise measurements and quantum communication. By simply lengthening the length of a laser resonator to decrease the stimulated emission rate of the laser, the coupling strength of all noise sources in the resonant laser field will be reduced, and thus the intensity noise of the output laser will be prominently suppressed. Based on theoretical analyses of the laser noise spectra, we experimentally implement a low-noise high-power single-frequency laser with a 1050 mm long resonator. With the assistance of an intracavity imaging system and nonlinear second-harmonic generation, the amplitude of the resonant relaxation oscillation peak and the shot-noise level (SNL) cutoff frequency are successfully reduced to 8.6 dB/Hz above SNL and 1.0 MHz, respectively, under the output power of 16 W. The work provides an effective way to develop a high-quality laser with high output power and low intensity noise.

Realization of a 101 W single-frequency continuous wave all-solid-state 1064 nm laser by means of mode self-reproduction.

We realized a 101 W single-frequency continuous wave (CW) all-solid-state 1064 nm laser by means of mode self-reproduction in this Letter. Two identical laser crystals were placed into a resonator to relax the thermal lens of the laser crystals, and an imaging system was employed to realize cavity mode self-reproduced at the places of the laser crystals. Single-frequency operation of the resonator was realized by employing a new kind of high extinction ratio optical diode based on the terbium scandium aluminum garnet crystal to realize a stable unidirectional operation of the laser, together with introducing a large enough nonlinear loss to the resonator to effectively suppress the multi-mode oscillation and mode hopping of the laser. As a result, a 101 W single-frequency 1064 nm laser in a single-ring resonator was achieved with 42.3% optical efficiency. The measured power stability for 8 h and the beam quality were better than ±0.73% and 1.2, respectively.

Acupuncture for postherpetic neuralgia: Systematic review and meta-analysis.

BACKGROUND: Acupuncture is widely used for postherpetic neuralgia (PHN) in China but its effect is unclear. We aim to evaluate the effect and safety of acupuncture for PHN. METHODS: The Cochrane Skin Group Trials Register, The Cochrane Central Register of Controlled Trials, MEDLINE, Embase, the Chinese Biomedical Literature Database, the China National Knowledge Infrastructure, and the gray literature were searched. Randomized controlled trials (RCTs) comparing acupuncture alone versus no treatment/another active therapy/sham acupuncture, or comparing acupuncture with another active therapy versus the same active therapy were included. RESULTS: Seven RCTs comparing acupuncture versus pharmacologic therapy were included. Meta-analysis was conducted for acupuncture's effect on PHN evaluating by pain intensity. Results from 2 RCTs showed that compared with pharmacologic therapy, acupuncture was better in decreasing the pain intensity measured by visual analog scale score (mean difference: 1.80, 95% confidence interval 1.72-1.87; P < .001). The limitations of the study are as follows: only trials comparing acupuncture versus pharmacologic therapy were included and all of the included trials were performed in China. CONCLUSION: There was not enough evidence to suggest that acupuncture was superior to pharmacologic therapy in improving global impression or life quality. No adverse effects about acupuncture were reported. In all, acupuncture is safe and might be effective in pain relieving for patients with PHN. Given the low quality of included studies, the results are not conclusive and more large-scale RCTs with high quality are needed.

The effect of electroacupuncture combined with donepezil on cognitive function in Alzheimer's disease patients: study protocol for a randomized controlled trial.

BACKGROUND: Alzheimer's disease is a progressive neurodegenerative disease. Although some of the current treatments offer some symptomatic relief, this disease cannot be cured at present. Electroacupuncture may be effective for Alzheimer's disease for cognitive function, but the evidence for its effectiveness is still limited. The aim of this study is to evaluate the add-on effect of electroacupuncture to donepezil for improving the cognitive function of Alzheimer's disease. METHODS/DESIGN: A total of 334 participants with Alzheimer's disease will be randomly assigned to either an electroacupuncture combined with donepezil group or a donepezil group with a ratio of 1:1. Participants in the electroacupuncture combined with donepezil group will receive electroacupuncture in addition to donepezil for 12 weeks and will keep taking donepezil for the following 24 weeks. Participants in the control group will take donepezil only. The primary outcome is the change from baseline in the total score of the Alzheimer's Disease Assessment Scale-cognition at week 12. A follow-up will be conducted 24 weeks after the treatment. DISCUSSION: We expect to verify the hypothesis that acupuncture in addition to donepezil is better than donepezil in improving the cognitive function of patients with Alzheimer's disease. This trial has a limitation that participant blinding is impossible. TRIAL REGISTRATION: Clinical Trials.gov: ID: NCT02305836 . Registered on 13 November 2014.

Acupuncture for Tourette Syndrome: A Systematic Review.

Tourette syndrome (TS) is a neuropsychiatric disorder that affects both children and adults. We searched for randomised controlled trials (RCTs) using acupuncture to treat TS written in English or Chinese without restrictions on publication status. Study selection, data extraction, and assessment of study quality were conducted independently by two reviewers. Meta-analyses were performed using Review Manager (RevMan) 5.3 software from the Cochrane Collaboration. Data were combined with the fixed-effect model based on a heterogeneity test. Results were presented as risk ratios for dichotomous data and mean differences (MDs) for continuous data. This review included 7 RCTs with a total of 564 participants. The combined results showed that acupuncture may have better short-term effect than Western medicine for TS and that acupuncture may be an effective adjuvant therapy in improving the effect of Western medicine on TS, but the evidence is limited because of existing biases. Rigorous high-quality RCTs are needed to verify these findings.

Influence of growth temperature on bulk and surface defects in hybrid lead halide perovskite films.

The rapid development of perovskite solar cells has focused its attention on defects in perovskites, which are gradually realized to strongly control the device performance. A fundamental understanding is therefore needed for further improvement in this field. Recent efforts have mainly focused on minimizing the surface defects and grain boundaries in thin films. Using time-resolved photoluminescence spectroscopy, we show that bulk defects in perovskite samples prepared using vapor assisted solution process (VASP) play a key role in addition to surface and grain boundary defects. The defect state density of samples prepared at 150 °C (∼10(17) cm(-3)) increases by 5 fold at 175 °C even though the average grains size increases slightly, ruling out grain boundary defects as the main mechanism for the observed differences in PL properties upon annealing. Upon surface passivation using water molecules, the PL intensity and lifetime of samples prepared at 200 °C are only partially improved, remaining significantly lower than those prepared at 150 °C. Thus, the present study indicates that the majority of these defect states observed at elevated growth temperatures originates from bulk defects and underscores the importance to control the formation of bulk defects together with grain boundary and surface defects to further improve the optoelectronic properties of perovskites.

The effectiveness and safety of acupuncture for patients with Alzheimer disease: a systematic review and meta-analysis of randomized controlled trials.

UNLABELLED: The use of acupuncture for treating Alzheimer disease (AD) has been increasing in frequency over recent years. As more studies are conducted on the use of acupuncture for treating AD, it is necessary to re-assess the effectiveness and safety of this practice. The objective of this study was to assess the effectiveness and safety of acupuncture for treating AD. Central Register of Controlled Trials (CENTRAL), PubMed, MEDLINE, Embase, PsycINFO, Chinese Biomedicine Literature (CBM), Chinese Medical Current Content (CMCC) and China National Knowledge Infrastructure (CNKI) were searched from their inception to June 2014. Randomized controlled trials (RCTs) with AD treated by acupuncture or by acupuncture combined with 1 kind of drugs were included. Two authors extracted data independently. The continuous data were expressed as mean differences (MD) with 95% confidence intervals (CIs). Weighted MD (WMD) was used instead of standardized MD (SMD) when the same scales were used. Adverse reactions related to acupuncture were also investigated.Ten randomized controlled trials with a total of 585 participants were included in the meta-analysis. The combined results of 6 trials showed that acupuncture was better than drugs at improving scores on the Mini Mental State Examination (MMSE) scale (MD 1.05, 95% CI 0.16-1.93). Evidence from the pooled results of 3 trials showed that acupuncture plus donepezil was more effective than donepezil alone at improving the MMSE scale score (MD 2.37, 95% CI 1.53-3.21). Out of 141 clinical trials, 2 trials reported the incidence of adverse reactions related to acupuncture. Seven out of 3416 patients had adverse reactions related to acupuncture during or after treatment; the reactions were described as tolerable and not severe.Acupuncture may be more effective than drugs and may enhance the effect of drugs for treating AD in terms of improving cognitive function. Acupuncture may also be more effective than drugs at improving AD patients' ability to carry out their daily lives. Moreover, acupuncture is safe for treating people with AD. PROTOCOL REGISTRATION: PROSPERO CRD42014009619. Protocol published in BMJ-open.

Hybrid light sensor based on ultrathin Si nanomembranes sensitized with CdSe/ZnS colloidal nanocrystal quantum dots.

We report the observation of a large enhancement of the wavelength-dependent photocurrent in ultrathin silicon nanomembranes (SiNM) decorated with colloidal CdSe/ZnS nanocrystal quantum dots (NQDs). Back-gated, field-effect transistor structures based on 75 nm-thick SiNMs are functionalized with self-assembled monolayers (SAMs) preventing surface oxidation and minimizing the surface defect densities. NQDs are drop cast on the active region of the device and the photocurrent is measured as a function of the excitation wavelength across the NQD absorption region. Photocurrent enhancement on the order of several hundred nA's is observed for NQD/SAM/SiNM devices compared to reference SAM/SiNM structures, with the device peak response closely correlated to the NQD absorption peak. We propose light-induced gating of the surface electrostatic potential and forward self-biasing of the FET channel as the two key mechanisms leading to the large photocurrent increase. Our findings open the possibility of employing silicon-nanocrystal hybrid structures for light sensing applications.

Acupuncture for benign prostatic hyperplasia: a systematic review protocol.

INTRODUCTION: Benign prostatic hyperplasia (BPH) is a non-malignant enlargement of the prostate commonly encountered in older men. BPH has been treated with acupuncture inside and outside China, but its effects are uncertain. This review aims to assess the efficacy and safety of acupuncture therapy for BPH. METHODS AND ANALYSIS: Seven databases will be searched from their inception: the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, Chinese Biomedical Database, the China National Knowledge Infrastructure, the VIP Database and Wanfang Database. Randomised controlled clinical trials using acupuncture to treat BPH will be included. Outcome measures included urological symptom scores, urodynamic measures and quality-of-life scales. Adverse events will be assessed and reported for safety evaluation. Study selection and data extraction will be performed by two independent reviewers. Quality assessment (assessment of risk of bias) and data synthesis will be implemented using Review Manager (RevMan) software (V.5.2.3). ETHICS AND DISSEMINATION: Ethical approval is not necessary because this systematic review will not include specific patient data. Updates will be conducted if there is enough new evidence that may cause any change in review conclusions. TRIAL REGISTRATION NUMBER: PROSPERO CRD42014013645.

Acupuncture for erectile dysfunction: a systematic review protocol.

INTRODUCTION: This systematic review protocol aims to provide a protocol for assessing the safety and effectiveness of acupuncture for the treatment of erectile dysfunction(ED). Previous systematic reviews did not draw convincing conclusions owing to high heterogeneity and few included randomised controlled trials, so it is necessary to reassess the efficacy and safety of acupuncture for ED. METHODS AND ANALYSIS: Eight electronic databases will be searched: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PubMed, EMBASE, PsycInfo, the Chinese Biomedical Literature Database (CBM), the Chinese Medical Current Content (CMCC) and the China National Knowledge Infrastructure (CNKI). Related Chinese literature will be searched in other Chinese databases. All relevant randomised controlled trials in English or Chinese without any restrictions of publication type will be included. The main outcome measure will be improvements in sexual activity assessed by validated questionnaires. Assessment of risk of bias, data synthesis and subgroup analysis will be carried out using Review Manager 5.3. ETHICS AND DISSEMINATION: The results of the systematic review will be disseminated via publication in a peer-reviewed journal and presented at a relevant conference. The data we will use do not include individual patient data, so ethical approval is not required. TRIAL REGISTRATION NUMBER: PROSPERO CRD42014013575.

Acupuncture for postherpetic neuralgia: a systematic review protocol.

INTRODUCTION: Postherpetic neuralgia (PHN) is one of the most common complications following herpes zoster. Clinical trials indicate that acupuncture could reduce pain and discomfort among patients with PHN. This protocol aims to describe how to accumulate the current evidence on the efficacy and safety of acupuncture for treating PHN. METHODS AND ANALYSIS: This systematic review will electronically search multiple databases including the Cochrane Skin Group Trials Register, MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), the Chinese Biomedical Literature Database (CBM), the Chinese Medical Current Content (CMCC) and the China National Knowledge Infrastructure (CNKI), and will hand search a list of medical journals as a supplement. Any clinical randomised controlled trials related to acupuncture for treating PHN will be included. Outcomes will include pain intensity, global impression, quality of life, safety and costs. By screening the titles, abstracts and full texts, two reviewers will independently select studies, extract data, and assess study quality. Meta-analysis of randomised controlled trials will be conducted using Revman 5.1 software. The results will be presented as risk ratio for dichotomous data, and standardised or weighted mean difference for continuous data. ETHICS AND DISSEMINATION: This systematic review does not need ethical approval because there are no data used in our study that are linked to individual patient data. Also, the findings will be disseminated through a peer-review publication or conference presentation. TRIAL REGISTRATION NUMBER: PROSPERO registration number: CRD42014009555.

Acupuncture for discomfort in patients during gastroscopy: a systematic review protocol.

INTRODUCTION: This systematic review aims to assess the effectiveness and safety of acupuncture for discomfort in patients during gastroscopy. METHODS AND ANALYSIS: Randomised controlled trials will be searched electronically in several databases including OVID MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Chinese Biomedical Literature Database (CBM), Chinese Medical Current Content (CMCC), Chinese Scientific Journal Database (VIP database), Wan-Fang Database and China National Knowledge Infrastructure (CNKI) from their respective founding dates to 30 April 2014. We will also try to find the literature by manually searching conference abstracts and reference lists. The study selection, extraction of data and assessment of study quality will be conducted independently by two researchers. Meta-analysis will be performed using RevMan V.5.2 statistical software. Data will be combined with either the fixed or random effect model based on a heterogeneity test. The results will be presented as a risk ratio for dichotomous data and standardised mean difference for continuous data. DISSEMINATION: This systematic review will evaluate the current evidence of acupuncture therapy for discomfort in patients during gastroscopy. The findings will be disseminated through peer-reviewed publication or conference presentations. TRIAL REGISTRATION NUMBER: PROSPERO CRD42014008966.