Output characteristics of 3-8 µm mid-infrared source based on BaGa4Se7 crystal.

An optical parametric oscillator based on B a G a 4 S e 7 crystal is constructed for use as a 3-8 µm mid-infrared source. The output characteristics of the light source, including wavelength tuning, beam quality, and energy stability, are studied, which are usually concerned differently in spectral analysis, imaging, and laser processing. When the light source operates far from the threshold, the mid-infrared output is poor in beam quality and good in energy stability, and the contradiction should be addressed in practice. The results provide guidance on the selection of operating parameters and performance optimization for the application of the B a G a 4 S e 7 based mid-infrared source in various settings.

Cascaded effect in a high-peak-power terahertz-wave parametric generator.

We demonstrate megawatt-level terahertz (THz)-wave generation via a Stokes-seed-injected THz-wave parametric generator and study the cascaded effect. The optical-to-THz conversion efficiency was 1.72 × 10-3, and the peak power was conservatively estimated to be 1.09 MW using the pulse width of the pump. More than 80% of the THz-wave energy came from primary parametric generation, with the rest coming from high-order parametric amplification. Clear cascaded Stokes spots of second to fourth order were observed, and the factors affecting the high-order parametric process are discussed. The cascaded parametric effect is beneficial for achieving a higher optical-to-THz conversion efficiency, thereby improving the performance of high-peak-power THz-wave parametric sources.

Widely tunable long-wave infrared difference frequency generation with a BaGa4Se7 crystal.

We report an experimental study of long-wave infrared difference frequency generation based on BaGa4Se7 crystal. The sources of two input wavelengths were the fundamental output of a Nd:YAG laser and its second-harmonic pumped ∼1.2µmKTiOPO4 optical parametric oscillator. A wide tuning range of 7.9-17.5 µm (>1.14 octave) was achieved, which reached the upper limit of the BaGa4Se7 transparency region. The spectra and pulse widths, input-output relationship, beam profile, wavelength tolerance, and angular acceptance of the phase-matching were characterized in detail. This presented coherent source can potentially be applied in multiple gas analyses and spectral imaging.

Cascaded difference frequency generation in organic crystal 4'-dimethylamino-N-methyl-4-stilbazolium tosylate.

In this Letter, we verified, for the first time to the best of our knowledge, an efficient cascaded difference frequency generation (DFG) with multi-order red shift. The experiment was performed with homemade organic crystals pumped by an optical parametric oscillator. The characteristics of energy conversion during DFG were investigated comprehensively at different frequencies and crystal thicknesses. Theoretical explanations were provided, based on the coupled-wave equations. The calculations predicted that the cascading effect contributed to a sustained growth of the DFG output (free from the saturation and shrinkage), especially in thick crystals. By measuring the optical spectrum, remarkable cascading processes of at least seven orders were observed. This effect shows the potential to overcome the quantum defect of the terahertz-wave DFG and fundamentally improve the conversion efficiency.

Antibiotic prophylaxis for surgical wound infections in clean and clean-contaminated surgery: an updated systematic review and meta-analysis.

BACKGROUND: The efficacy and necessity of prophylactic antibiotics in clean and clean-contaminated surgery remains controversial. METHODS: The studies were screened and extracted using databases including PubMed, Embase, Cochrane Library, Web of Science, and Clinical Trials.gov according to predefined eligibility criteria. Randomized controlled trials (RCTs) comparing the effect of preoperative and postoperative prophylactic antibiotic use on the incidence of surgical site infections (SSIs) in patients undergoing any clean or clean-contaminated surgery. RESULTS: A total of 16,189 participants in 48 RCTs were included in the primary meta-analysis following the eligibility criteria. The pooled odds ratio (OR) for SSI with antibiotic prophylaxis versus placebo was 0.60 (95% CI: 0.53-0.68). The pooled OR among gastrointestinal, oncology, orthopedics, neurosurgery, oral, and urology surgery was 3.06 (95% CI: 1.05-8.91), 1.16 (95% CI: 0.89-1.50), 2.04 (95% CI: 1.09-3.81), 3.05 (95% CI: 1.25-7.47), 3.55 (95% CI: 1.78-7.06), and 2.26 (95% CI: 1.12-4.55), respectively. Furthermore, the summary mean difference (MD) for patients' length of hospitalization was -0.91 (95% CI: -1.61, -0.16). The results of sensitivity analyses for all combined effect sizes showed good stability. CONCLUSION: Antibiotics are both effective, safe, and necessary in preventing surgical wound infections in clean and clean-contaminated procedures, attributed to their reduction in the incidence of surgical site infections as well as the length of patient hospitalization.

Empirical Policy Optimization for n-Player Markov Games.

In single-agent Markov decision processes, an agent can optimize its policy based on the interaction with the environment. In multiplayer Markov games (MGs), however, the interaction is nonstationary due to the behaviors of other players, so the agent has no fixed optimization objective. The challenge becomes finding equilibrium policies for all players. In this research, we treat the evolution of player policies as a dynamical process and propose a novel learning scheme for Nash equilibrium. The core is to evolve one's policy according to not just its current in-game performance, but an aggregation of its performance over history. We show that for a variety of MGs, players in our learning scheme will provably converge to a point that is an approximation to Nash equilibrium. Combined with neural networks, we develop an empirical policy optimization algorithm, which is implemented in a reinforcement-learning framework and runs in a distributed way, with each player optimizing its policy based on own observations. We use two numerical examples to validate the convergence property on small-scale MGs, and a pong example to show the potential on large games.

BViT: Broad Attention-Based Vision Transformer.

Recent works have demonstrated that transformer can achieve promising performance in computer vision, by exploiting the relationship among image patches with self-attention. They only consider the attention in a single feature layer, but ignore the complementarity of attention in different layers. In this article, we propose broad attention to improve the performance by incorporating the attention relationship of different layers for vision transformer (ViT), which is called BViT. The broad attention is implemented by broad connection and parameter-free attention. Broad connection of each transformer layer promotes the transmission and integration of information for BViT. Without introducing additional trainable parameters, parameter-free attention jointly focuses on the already available attention information in different layers for extracting useful information and building their relationship. Experiments on image classification tasks demonstrate that BViT delivers superior accuracy of 75.0%/81.6% top-1 accuracy on ImageNet with 5M/22M parameters. Moreover, we transfer BViT to downstream object recognition benchmarks to achieve 98.9% and 89.9% on CIFAR10 and CIFAR100, respectively, that exceed ViT with fewer parameters. For the generalization test, the broad attention in Swin Transformer, T2T-ViT and LVT also brings an improvement of more than 1%. To sum up, broad attention is promising to promote the performance of attention-based models. Code and pretrained models are available at https://github.com/DRL/BViT.

UNMAS: Multiagent Reinforcement Learning for Unshaped Cooperative Scenarios.

Multiagent reinforcement learning methods, such as VDN, QMIX, and QTRAN, that adopt centralized training with decentralized execution (CTDE) framework have shown promising results in cooperation and competition. However, in some multiagent scenarios, the number of agents and the size of the action set actually vary over time. We call these unshaped scenarios, and the methods mentioned above fail in performing satisfyingly. In this article, we propose a new method, called Unshaped Networks for Multiagent Systems (UNMAS), which adapts to the number and size changes in multiagent systems. We propose the self-weighting mixing network to factorize the joint action-value. Its adaption to the change in agent number is attributed to the nonlinear mapping from each-agent Q value to the joint action-value with individual weights. Besides, in order to address the change in an action set, each agent constructs an individual action-value network that is composed of two streams to evaluate the constant environment-oriented subset and the varying unit-oriented subset. We evaluate UNMAS on various StarCraft II micromanagement scenarios and compare the results with several state-of-the-art MARL algorithms. The superiority of UNMAS is demonstrated by its highest winning rates especially on the most difficult scenario 3s5z_vs_3s6z. The agents learn to perform effectively cooperative behaviors, while other MARL algorithms fail. Animated demonstrations and source code are provided in https://sites.google.com/view/unmas.

Lidocaine-loaded reduced graphene oxide hydrogel for prolongation of effects of local anesthesia: In vitro and in vivo analyses.

Lidocaine is widely used as a local anesthetic for alleviation of post-operative pain and for management of acute and chronic painful conditions. Although several approaches are currently used to prolong the duration of action, an effective strategy to achieve neural blockage for several hours remains to be identified. In this study, a lidocaine-loaded Pluronic® F68-reduced graphene oxide hydrogel was developed to achieve sustained release of lidocaine. Fourier transform infrared spectroscopy, X-ray diffraction, and Raman spectroscopy confirmed the synthesis of Pluronic® F68-reduced graphene oxide. Transmission electron microscopy showed wrinkled, flat nanosheets with micelles attached. The developed hydrogel showed desirable pH, viscosity, adhesiveness, hardness, and cohesiveness for topical application. The ex vivo release study demonstrated the ability of the Pluronic® F68-reduced graphene oxide hydrogel to prolong release up to 10 h, owing to the strong π-π interactions between the graphene oxide and the lidocaine. In comparison with a commercial lidocaine ointment, the developed graphene oxide hydrogel showed sustained anesthetic effect in the radiant heat tail flick test and sciatic nerve block model. Thus, this study demonstrates the potential of using Pluronic® F68-reduced graphene oxide nanocarriers to realize prolonged effects of local anesthesia for effective pain management.

[Clinical analysis of 47 patients with psoriasis arthropathy treated by traditional Chinese medicine syndrome differentiation and integrative medicine].

OBJECTIVE: To analyze the clinical characteristics of psoriasis arthropathy (PA) and to explore the effect of treatment by traditional Chinese medicine (TCM) syndrome differentiation and integrative medicine. METHODS: The initiating characteristics, clinical manifestations, related laboratory and X-ray data as well as the therapeutic efficacy of syndrome dependent TCM and integrative medicine on 47 PA patients were analyzed. RESULTS: Among all the 47 patients, 38 (80.6%) had the skin lesion revealed earlier to joint symptoms, the average time between the appearance of skin lesion and joint symptoms was 9.2 years; joint X-ray abnormality was found in 32 cases (68.1%); and psoriasis nail involvement was found in 33 cases (70.2%). Seventeen patients were treated with TCM alone and obtained satisfactory results, while the other 30 patients, were treated by integrative medicine with the dosage of medicine reduced immediately after symptoms were relieved, and finally cured or improved. CONCLUSION: TCM and integrative medicine are effective in treating PA, with lesser side effects.

[Clinical study of three-dimensional strapping reduction in treatment of patellar fracture].

Objective: To investigate the effectiveness of three-dimensional strapping reduction in treatment of patellar fracture. Methods: Between January 2015 and June 2015, thirty-two patients were randomly allocated to three-dimensional strapping reduction group (trial group) and towel clamp reduction group (control group). There was no significant difference in age, gender, damage side, interval from injury to opreration, fracture pattern, and cause of injury ( P>0.05). The operation time, fluoroscopy time, fracture healing time, postoperative Hospital for Special Surgery (HSS) scores, and complications were collected and analysed. Results: All incisions healed at stage I. All patients of 2 groups were followed up 10-14 months (mean, 12.4 months). The operation time and fluoroscopy time of trial group were both shorter than those of control group ( t=6.212, P=0.000; t=6.585, P=0.000). X-ray films showed that the fractures in both groups healed successfully and there was no significant difference in healing time between groups ( t=1.973, P=0.058). Bone nonunion, infection, and failure fixation were not found in both groups. HSS scores of trial group (91.6±3.8) was higher than that of control group (86.4±5.5) ( t=-3.105, P=0.004). Conclusion: Compared with towel clamp reduction, the three-dimensional strapping reduction in treatment of patellar fracture has the advantages of shorter operation time and fluoroscopy time, better knee function after operation, and satisfactory fracture healing.

[Comparison of primary extraovarian peritoneal serous papillary carcinoma with stage III-IV ovarian papillary serous carcinoma].

OBJECTIVE: Extraovarian peritoneal serous papillary carcinoma (EPSPC) is both histologically and clinically similar to stage III-IV ovarian papillary serous carcinoma (OPSC). The purpose of this study is to investigate the clinical findings, treatment, and outcome of EPSPC patients compared with stage III-IV OPSC patients. METHODS: The data of 12 EPSPC patients and 45 stage III-IV OPSC patients were retrospectively reviewed, comparing the characteristics on clinical presentation and treatment, sensitivity to first-line chemotherapy agents and survival. RESULTS: By analysis of patients' characteristics, presenting signs and symptoms, type and extent of surgery, tumor response to first-line chemotherapy, recurrence-free interval, recurrence site and serum CA-125 levels, no significant difference was observed between the EPSPC patients and stage III-IV OPSC controls. The prevailing presenting symptoms were abdominal mass and ascites. The mainstay of treatment was debulking surgery followed by adjuvant platinum-based chemotherapy. The complete clinical response of stage III-IV OPSC was 91.8% compared with 25.0% for women with EPSPC (P < 0.01). CONCLUSION: The clinical and surgical characteristics of EPSPC are similar to those of stage III-IV OPSC. When the same treatment strategy is applied, similar response and survival are expected in either condition.

General anesthesia versus local anesthesia for penetrating keratoplasty: a prospective study.

AIM: To examine which anesthesia general or local is more effective for penetrating keratoplasty (PKP). METHODS: Patients with indications for PKP (n=141) were enrolled in a prospective study and randomly divided into general anesthesia group (group A, 70 eyes) and local anesthesia group (group B, 71 eyes). Patients received optical PKP (group A1, 30 eyes; group B1, 30 eyes) or therapeutic PKP (group A2, 40 eyes; group B2, 41 eyes). Measurement of anterior chamber treatment time (T) for PKP patients and the ratio (R) of the area of the pupils to that of recipient graft region. T and R values, as well as perioperative and postoperative complications, were compared between groups A and B using t-test or χ (2) test. RESULTS: Patients were followed for 2wk after PKP. T was (13.45±8.64)min for group A and (7.36±5.24)min for group B, a statistically significant difference (P<0.001). The R value for group A was stable during the operation, while for PKP patients in group B the value initially increased then gradually decreased to normal after suturing. In group B, extrusion of intraocular contents occurred in 5 eyes, and iridal prolapse occured in 11 cases; no perioperative complications occurred in group A. Relapse rate for fungal keratitis was 13.04% in group B and 0% in group A. CONCLUSION: Under general anesthesia, pupils remaine stable during PKP and perioperative complications are averted. General anesthesia gives more time to treat pathological changes in the anterior chamber and treatment success rate is higher.

[Primary peritoneal malignant tumor: clinical analysis of 28 cases].

BACKGROUND & OBJECTIVE: Primary malignant peritoneal tumor is a kind of rare malignancy. Its morphology and clinical manifestations are very similar to the advanced ovarian cancer, therefore, they are usually misdiagnosed and the proper treatment were delayed. This paper analyzed the clinical characteristics, diagnosis, treatment, and prognosis of primary malignant peritoneal tumor. METHODS: The clinical data of 28 cases of primary peritoneal malignant tumor patients admitted between January 1996 to February 2002 in People's Hospital, Peking University, was analyzed retrospectively. There are 20 cases of primary peritoneal seropapillary adenocarcinoma, 8 cases of primary peritoneal malignant Muellerian tube tumor. Their age ranged from 33 to 74, with median age of 54. RESULTS: Among 28 patients, 22 were misdiagnosed preoperatively, the misdiagnose rate were 79%. In all cases, cytoreductive surgery were performed. Postoperative chemotherapy were given either with CAP regimen or TP regimen. Postoperative survival time was 1-83 months, the median survival time was 30 months. CONCLUSION: The recognition of this special tumor should be stressed, to improve early diagnosis and treatment. The authors suggest that cytoreductive surgery on time and postoperative adjuvant chemotherapy should be implemented to improve survival rate.