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The integrity of collagen matrix structure is a prerequisite for effectively inducing biomimetic remineralization. Repeated low pH stimulation activates matrix metalloproteinases (MMPs) in dental caries. Activated MMPs cause the breakdown of collagen fibrils. Collagen stabilization is a major obstacle to the clinical application of remineralization templates. Here, galardin-loaded poly(amido amine) (PAMAM)-NGV (PAMAM-NGV@galardin, PNG) is constructed to induce collagen stabilization and dentin biomimetic remineralization simultaneously, in order to combat early caries in dentin. PAMAM acts in the role of nucleation template for dentin remineralization, while galardin acts as the role of MMPs inhibitor. NGV peptides modified on the surface of dendrimer core can form small clusters with synergistic movement in short range, and those short-range clusters can form domain areas with different properties on the surface of PAMAM core and restrict the movement of collagen, favoring collagen crosslinking, which can be explained through the computational simulation analysis results. NGV peptides and galardin show a dual collagen-protective effect, laying the foundation for the dentin remineralization effect induced by PAMAM. PNG induces dentin remineralization in an environment with collagenase, meanwhile showsing anti-dentin caries efficacy in vivo. These findings indicate that PNG has great potential to combat early dentin caries for future clinical application.

A femtosecond chirped pulse amplifier based on cryogenically cooled Fe:ZnSe was demonstrated at 333 Hz—33 times higher than previous results achieved at near-room-temperature. The long upper-state lifetime allows free-running, diode-pumped Er:YAG lasers to be used as pump lasers. 250-fs, 4.59-mJ pulses are produced with a center wavelength of 4.07 µm, which avoids strong atmospheric CO2 absorption that cuts on around 4.2 µm. It is therefore possible to operate the laser in ambient air with good beam quality. By focusing the 18-GW beam in air, harmonics up to the ninth order were observed indicating its potential for use in strong-field experimentation.

Lasers capable of generating attosecond X-ray pulses in the water window (282 to 533 eV) through high-order harmonic generation are normally based on inefficient, multi-stage optical parametric amplifiers or optical parametric chirped pulse amplifiers pumped by femtosecond or picosecond lasers. Here we report a very efficient single amplification stage laser based on traditional chirped pulse amplification capable of producing 4 mJ, near-transform limited 44 fs (μm. The ≈90 GW peak power is the highest value ever reached at this wavelength. In order to fully compress the laser pulses our system is built in a nitrogen box. Our system utilizes water cooled chromium doped zinc selenide (Cr2+:ZnSe) as the gain medium and is pumped by a commercial nanosecond holmium doped yttrium-aluminum-garnet (Ho:YAG) laser.

A ZnGeP2-based optical parametric chirped-pulse amplifier pumped by a 2 µm Ho:YLF generated a 3 mJ pulse at 3 µm. The bandwidth supports a 50 fs transform-limited duration.

3.2-mJ, 92-fs pulses centered at 3.1 µm are generated at a 1-kHz repetition rate through a tabletop optical parametric chirped pulse amplification (OPCPA) system based on ZnGeP2 crystals. Pumped by a 2-µm chirped pulse amplifier with a flat-top beam profile, the amplifier achieves a 16.5% overall efficiency, which, to the best of our knowledge, is the highest efficiency achieved by OPCPA at this wavelength. Harmonics up to the seventh order are observed after focusing the output in the air.

The advent of chirped-pulse amplification in the 1980s and femtosecond Ti:sapphire lasers in the 1990s enabled transformative advances in intense laser–matter interaction physics. Whereas most of experiments have been conducted in the limited near-infrared range of 0.8–1 μm, theories predict that many physical phenomena such as high harmonic generation in gases favor long laser wavelengths in terms of extending the high-energy cutoff. Significant progress has been made in developing few-cycle, carrier-envelope phase-stabilized, high-peak-power lasers in the 1.6–2 μm range that has laid the foundation for attosecond X ray sources in the water window. Even longer wavelength lasers are becoming available that are suitable to study light filamentation, high harmonic generation, and laser–plasma interaction in the relativistic regime. Long-wavelength lasers are suitable for sub-bandgap strong-field excitation of a wide range of solid materials, including semiconductors. In the strong-field limit, bulk crystals also produce high-order harmonics. In this review, we first introduce several important wavelength scaling laws in strong-field physics, then describe recent breakthroughs in short- (1.4–3 μm), mid- (3–8 μm), and long-wave (8–15 μm) infrared laser technology, and finally provide examples of strong-field applications of these novel lasers. Some of the broadband ultrafast infrared lasers will have profound effects on medicine, environmental protection, and national defense, because their wavelengths cover the water absorption band, the molecular fingerprint region, as well as the atmospheric infrared transparent window.

Recently, people’s demand for action recognition has extended from the initial high classification accuracy to the high accuracy of the temporal action detection. It is challenging to meet the two requirements simultaneously. The key to behavior recognition lies in the quantity and quality of the extracted features. In this paper, a two-stream convolutional network is used. A three-dimensional convolutional neural network (3D-CNN) is used to extract spatiotemporal features from the consecutive frames. A two-dimensional convolutional neural network (2D-CNN) is used to extract spatial features from the key-frames. The integration of the two networks is excellent for improving the model’s accuracy and can complete the task of distinguishing the start–stop frame. In this paper, a multi-scale feature extraction method is presented to extract more abundant feature information. At the same time, a multi-task learning model is introduced. It can further improve the accuracy of classification via sharing the data between multiple tasks. The experimental result shows that the accuracy of the modified model is improved by 10%. Meanwhile, we propose the confidence gradient, which can optimize the distinguishing method of the start–stop frame to improve the temporal action detection accuracy. The experimental result shows that the accuracy has been enhanced by 11%.

We present the generation of femtosecond pulses centered at 3 and 8 μm through a ZnGeP2-based Optical Parametric Chirped Pulse Amplifier. The output can be used for a two-color high harmonic generation scheme.

Mid-infrared pulses with 200 nJ energy and 200 nm bandwidth were generated at 4.1 µm and 60 kHz repetition rate. The highly-stable LiGaS2-based Optical Parametric Amplifier was pumped by a turn-key, commercially available Yb:KGW laser.

It is well known that the gain and efficiency of an amplifier with a quasi-three level medium such as Ho:YLF is strongly affected by the coolant temperature. By cooling the Ho:YLF crystals of a two-stage energy booster in a Ho:YLF Chirped Pulse Amplification laser with -20°C thermoelectric cooling rather than room temperature water, a 60 mJ pulse energy at 1 kHz repetition rate was achieved with 8.5 mJ input.

With the rapid development of artificial intelligence and 5G technology, the development process of smart city has been greatly accelerated. An important part of the development of smart city is to improve the ability of video monitoring equipment to analyze the content of the video. This paper is to identify the specific abnormal behaviors in the video, including climbing, fighting and falling. The identification of these abnormal behaviors is helpful to find out the danger in time and intervene to ensure personal safety and social stability. Therefore, this paper proposes a deep learning method based on edge extraction. In the first step, the video is decomposed into several frames, and the canny edge detection algorithm is used to extract the edge of the images. In the second step, the extracted edge information is used as the input of the 3D convolutional neural network, and the 3D convolutional neural network model is trained iteratively to recognize the abnormal behaviors. Through a large number of experiments, the effectiveness of the proposed algorithm is verified.

We present a multi-pass Chirped Pulse Amplification system using Ho:YLF that can produce 32 mJ pules at 2.05 pm and 1 kHz repetition rate. The seed is generated from DC-OPA driven by a Ti:Sapphire laser.

A single-stage chirped-pulse amplifier centered at 2.5 wm was developed to produce 3.5 mJ, 44 fs pulses at 1 kHz. The 80 GW peak power allows attosecond X-ray pulses generation in the water window.

We present a Ho:YLF Chirped-Pulse Amplification (CPA) laser for pumping a longwave infrared Optical Parametric Chirped Pulse Amplifier (OPCPA) at a 1 kHz repetition rate. By utilizing a Ti:Sapphire laser as a frontend, 5-{\mu}J seed pulses at 2051 nm laser pulse are generated in a Dual-Chirp Optical Parametric Amplifier (DC-OPA), which are amplified to 28 mJ pulses with a pulse duration of 6.8 ps. The scheme offers a potential driver for two-color (800 nm and 8 {\mu}m) high harmonic generation with an increased keV X-ray photon flux., Comment: 5 pages, 5 figures

Lasers capable of generating attosecond X-ray pulses in the water window (282 to 533 eV) through high-order harmonic generation are normally based on inefficient, multi-stage optical parametric amplifiers or optical parametric chirped pulse amplifiers pumped by femtosecond or picosecond lasers. Here we report a very efficient single amplification stage laser based on traditional chirped pulse amplification capable of producing 4 mJ, near-transform limited 44 fs (

Data sources MEDLINE (via PubMed), EMBASE, the Cochrane library (CENTRAL) and the clinicaltrials.gov database were used as the data sources for the systematic review. Date restrictions were from database inception to October 2018 and only articles published in English were included. Hand searching of reference lists was carried out. Missing data was sought from authors if required for analysis.Study selection Two independent researchers identified randomised controlled trials assessing the outcomes of pulpotomy procedures on vital permanent teeth with immature apices. Studies were only included if they reported clinical and radiographic success rates. After full text assessment, any disagreement between reviewers was resolved via discussion.Data extraction and synthesis Data extraction was carried out using a table which was custom designed for this study. Accuracy of data was checked by a third reviewer. Strict criteria for healing were used for clinical and radiographic outcomes. Success rates were calculated for each intervention. Statistical testing on the data was completed using a fixed- or random-effect model depending on heterogeneity identified, using the i2 test. Results were presented as relative risks with 95% confidence intervals. Two independent reviewers assessed the quality of studies using the Cochrane risk of bias assessment tool.Results Following screening of 1364 articles, five studies were included for qualitative analysis and two for quantitative analysis. All included studies were assessed as having a high risk of bias, which was attributed to the nature of the intervention and challenges in blinding the researcher. Four out of the five included studies were assessed as having a low risk of bias for detection, because of blinding of the investigator assessing the outcome. The remaining study had an unclear risk of bias for this parameter. No significant difference was detected between mineral trioxide aggregate (MTA) and calcium hydroxide (CH) at 6 months or 12 months post-treatment. MTA was also compared to platelet-rich fibrin (PRF), calcium-enriched mixture (CEM) and triple antibiotic paste (TAP) in individual studies with no statistically significant differences identified between groups. Significant clinical and radiographic differences were observed in favour of MTA and TAP compared to abscess remedy (AR), although this was noted as weak evidence.Conclusions Based on the present evidence, there were similar success rates when using MTA, CH, CEM, RPF and TAP as medicaments for pulpotomies in the treatment of immature permanent teeth. More high-quality RCTs are needed in this field in future studies.

The International Associations for Dental Research (IADR) annual meeting is one of the most important dental meetings throughout the world, and researches about paediatric dentistry presented in this platform are often used to guide clinical work. To evaluate the publication outcomes of oral and poster paediatric proceedings, which were accepted by the International Associations for Dental Research (IADR), annual meetings from 2010 to 2016 and to analyse the possible factors influencing an abstract's progression to publication. Oral and poster abstracts were retrieved from the official website of IADR (2010-2016). Searching for subsequent publications was conducted in PubMed and Google Scholar (up to March 2019). Two authors independently selected studies, collected, and analysed data. A total of 1396 abstracts were identified, including 275 oral presentations and 1121 poster presentations. Finally, 606 were published in peer-reviewed journals, with a publication rate of 43.41%. Abstracts were published earlier if it is from Europe, well funded, presented orally, or with large sample size. The high publication rate of the IADR proceedings supported the impact of IADR annual meetings on paediatric dentistry in the last 10 years.

Rational:Dental abnormalities can occur at any stage of tooth development. Of these abnormalities, true generalized microdontia is a rare condition in which all teeth are smaller than normal, while hypodontia is defined as the absence of 1 to 5 teeth. As far as we are aware, no article has r

The paper introduced the principle and configuration of transformer chromatogram online monitoring system. The key issues of online chromatogram were summarized. According to the operation experience in Taizhou electric power company, the characteristics of transformer chromatogram online monitoring system were put forward, the points for attention on operating these kind of systems is analyzed. (5 pages)

Recently, Semiconductor sensor and thermal conductivity sensor are widely used for gas detection in transformer online monitors. Since the long-time stability or precision of these sensors is not satisfactory, the present researcher studied the application of FTIR in such monitors. In the wide measuring range of online monitoring, Absorbance Law is not always applicable, thus a non-linear calibration model was necessary. Experiments were done to set up the calibration model. A gas dilution system was designed. With the system, standard samples of fault gas including CH4, C2H2, C2H4 and C2H6 were diluted to different concentration. BOMEM MB104 FTIR Spectrometer was used to collect spectra of gases. Curve fitting of the output of FTIR was done, and the effect of quantitative feature and concentration range on quantitative analysis was investigated. In addition, the lowest detection limit was tested. Experiment and calculation results show: accuracy can be improved by taking strong peak height at low concentration range, taking peak area or weak peak height at high concentration range as quantitative feature, and using third order polynomial to fit the output curve of FTIR. The lowest detecting limit of C2H2 with 2.4m gas cell is below 0.3ml/l and that of 10cm cell is below 3ml/l.