Study on Linewidth and Phase Noise Characteristics of a Narrow Linewidth External Cavity Diode Laser.

In the field of inter-satellite laser communication, achieving high-quality communication and compensating for the Doppler frequency shift caused by relative motion necessitate lasers with narrow linewidths, low phase noise, and the ability to achieve mode-hop-free tuning within a specific range. To this end, this paper investigates a novel external cavity diode laser (ECDL) with a frequency-selective F-P etalon structure, leveraging the external cavity F-P etalon structure in conjunction with an auxiliary filter to achieve single longitudinal mode selection. The laser undergoes linewidth testing using a delayed self-heterodyne beating method, followed by the testing of its phase noise and frequency noise characteristics using a noise analyzer, yielding beat spectra and noise power spectral density profiles. Furthermore, the paper introduces an innovative bidirectional temperature-scanning laser method to achieve optimal laser-operating point selection and mode-hop-free tuning. The experimental results showcase that the single longitudinal mode spectral side-mode suppression ratio (SMSR) is around 70 dB, and the output power exceeds 10 mW. Enhancing the precision of the F-P etalon leads to a more pronounced suppression of low-frequency phase noise, reducing the Lorentzian linewidth from the initial 10 kHz level to a remarkable 5 kHz level. The bidirectional temperature-scanning laser method not only allows for the selection of the optimal operating point but also enables mode-hop-free tuning within 160 pm.

BACE1 SUMOylation deregulates phosphorylation and ubiquitination in Alzheimer's disease pathology.

BACE1 is essential for the generation of amyloid-ß (Aß) that likely initiates the toxicity in Alzheimer's disease (AD). BACE1 activity is mainly regulated by post-translational modifications, but the relationship between these modifications is not fully characterized. Here, we studied the effects of BACE1 SUMOylation on its phosphorylation and ubiquitination. We demonstrate that SUMOylation of BACE1 inhibits its phosphorylation at S498 and its ubiquitination in vitro. Conversely, BACE1 phosphorylation at S498 suppresses its SUMOylation, which results in promoting BACE1 degradation in vitro. Furthermore, an increase in BACE1 SUMOylation is associated with the progression of AD pathology, while its phosphorylation and ubiquitination are decreased in an AD mouse model. Our findings suggest that BACE1 SUMOylation reciprocally influences its phosphorylation and competes against its ubiquitination, which might provide a new insight into the regulations of BACE1 activity and Aß accumulation.

ACL stump and ACL femoral landmarks are equally reliable in ACL reconstruction for assisting ACL femoral tunnel positioning.

PURPOSE: This study aimed to comparatively evaluate the accuracy of femoral tunnel positioning after anatomic single-bundle anterior cruciate ligament (ACL) reconstruction performed with the remnant preservation (RP) technique versus the non-remnant preservation (NRP) technique. METHODS: A retrospective review of 145 patients who underwent ACL reconstruction from May 2020 to May 2022 were performed in this single-surgeon study. A total of 120 patients met the inclusion criteria and were allocated into two groups according to the surgical technique (i.e. RP group and NRP group). The relative location of the femoral tunnel in the lateral condyle was evaluated as a percentage using a standardized grid system on the three-dimensional computed tomography (3D-CT) image. The accuracy and precision of the RP group were assessed based on published anatomical data in direct comparison with the NRP group. RESULTS: According to the surgical procedure, 57 of the 120 patients included were allocated into the RP group, and 63 into the NRP group. Significant differences were observed between the two groups in terms of tunnel position (posterior-to-distal (PD): 28.4 ± 5.4% (RP) vs. 31.8 ± 5.3% (NRP); P = 0.01), (anterior-to-posterior (AP): 32.6 ± 7.7% (RP) vs. 38.8 ± 7.7% (NRP); P = 0.00), while no significant differences were found in terms of the accuracy (8.6% (RP) vs. 8.9% (NRP); n.s) and precision (4.4% (RP) vs. 5.6% (NRP); n.s) of femoral tunnel positioning between the two groups. CONCLUSIONS: From this single-surgeon study, it was concluded that there were no differences in the creation of ACL femoral tunnel between the RP technique and the non-remnant preserving technique. Meanwhile, the RP technique would not sacrifice the ideal position of the femoral tunnel and is able to retain the possible benefits of the ACL stump. LEVEL OF EVIDENCE: Level III.

General Image Fusion for an Arbitrary Number of Inputs Using Convolutional Neural Networks.

In this paper, we propose a unified and flexible framework for general image fusion tasks, including multi-exposure image fusion, multi-focus image fusion, infrared/visible image fusion, and multi-modality medical image fusion. Unlike other deep learning-based image fusion methods applied to a fixed number of input sources (normally two inputs), the proposed framework can simultaneously handle an arbitrary number of inputs. Specifically, we use the symmetrical function (e.g., Max-pooling) to extract the most significant features from all the input images, which are then fused with the respective features from each input source. This symmetry function enables permutation-invariance of the network, which means the network can successfully extract and fuse the saliency features of each image without needing to remember the input order of the inputs. The property of permutation-invariance also brings convenience for the network during inference with unfixed inputs. To handle multiple image fusion tasks with one unified framework, we adopt continual learning based on Elastic Weight Consolidation (EWC) for different fusion tasks. Subjective and objective experiments on several public datasets demonstrate that the proposed method outperforms state-of-the-art methods on multiple image fusion tasks.

Deep HDR Deghosting by Motion-Attention Fusion Network.

Multi-exposure image fusion (MEF) methods for high dynamic range (HDR) imaging suffer from ghosting artifacts when dealing with moving objects in dynamic scenes. The state-of-the-art methods use optical flow to align low dynamic range (LDR) images before merging, introducing distortion into the aligned LDR images from inaccurate motion estimation due to large motion and occlusion. In place of pre-alignment, attention-based methods calculate the correlation between the reference LDR image and non-reference LDR images, thus excluding misaligned regions in LDR images. Nevertheless, they also exclude the saturated details at the same time. Taking advantage of both the alignment and attention-based methods, we propose an efficient Deep HDR Deghosting Fusion Network (DDFNet) guided by optical flow and image correlation attentions. Specifically, the DDFNet estimates the optical flow of the LDR images by a motion estimation module and encodes that optical flow as a flow feature. Additionally, it extracts correlation features between the reference LDR and other non-reference LDR images. The optical flow and correlation features are employed to adaptably combine information from LDR inputs in an attention-based fusion module. Following the merging of features, a decoder composed of Dense Networks reconstructs the HDR image without ghosting. Experimental results indicate that the proposed DDFNet achieves state-of-the-art image fusion performance on different public datasets.

Efflux identification and engineering for ansamitocin P-3 production in Actinosynnema pretiosum.

Ansamitocin P-3 (AP-3) exhibits potent biological activities against various tumor cells. As an important drug precursor, reliable supply of AP-3 is limited by low fermentation yield. Although different strategies have been implemented to improve AP-3 yield, few have investigated the impact of efflux on AP-3 production. In this study, AP-3 efflux genes were identified through combined analysis of two sets of transcriptomes. The production-based transcriptome was implemented to search for efflux genes highly expressed in response to AP-3 accumulation during the fermentation process, while the resistance-based transcriptome was designed to screen for genes actively expressed in response to the exogenous supplementation of AP-3. After comprehensive analysis of two transcriptomes, six efflux genes outside the ansamitocin BGC were identified. Among the six genes, individual deletion of APASM_2704, APASM_6861, APASM_3193, and APASM_2805 resulted in decreased AP-3 production, and alternative overexpression led to AP-3 yield increase from 264.6 to 302.4, 320.4, 330.6, and 320.6 mg/L, respectively. Surprisingly, APASM_2704 was found to be responsible for exportation of AP-3 and another macro-lactam antibiotic pretilactam. Furthermore, growth of APASM_2704, APASM_3193, or APASM_2805 overexpression mutants was obviously improved under 300 mg/L AP-3 supplementation. In summary, our study has identified AP-3 efflux genes outside the ansamitocin BGC by comparative transcriptomic analysis, and has shown that enhancing the transcription of transporter genes can improve AP-3 production, shedding light on strategies used for exporter screening and antibiotic production improvement. KEY POINTS: • AP-3-related efflux genes were identified by transcriptomic analysis. • Deletion of the identified efflux genes led in AP-3 yield decrease. • Overexpression of the efflux genes resulted in increased AP-3 production.

Impact of sludge conditioning treatment on the bioavailability of pyrene in sewage sludge.

Conditioning is an indispensable step to improve mechanical dewatering of municipal sewage sludge. However, it is still unclear how sludge conditioning treatments impact the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in sewage sludge that potentially influences the biodegradation of PAHs during the composting of dewatered sludge cake. In the present study, five sludge conditioning treatments, including chemical acidification, bioleaching driven by Acidithiobacillus ferrooxidans, chemical conditioning with Fe[III] and CaO, and chemical conditioning with either aluminum polychloride (PACl) or polyacrylamide (PAM), were investigated to reveal their respective impacts on the bioavailability of pyrene in sewage sludge. The bioavailability of pyrene in conditioned sludge was evaluated by using the n-butanol extraction method. The results showed that the bioavailable fraction of pyrene increased from 59.1% in raw sludge to 68.7% in chemically acidified sludge and 79.3% in bioleached sludge, while the other three conditioning approaches did not significantly change the bioavailability of pyrene. During chemical acidification or bioleaching of sludge, cellular membrane damage of sludge microbial cells induced changes in sludge chemical and physical properties. Ridge regression analysis revealed that during these two conditioning processes the contribution rates of the changes in sludge chemical properties and physical properties on the enhancement of pyrene bioavailability were 33.0% and 67.1%, respectively. Therefore, chemical acidification and bioleaching conditioning treatments can enhance the bioavailability of pyrene in sewage sludge, mainly through changing the relative hydrophobicity and particle size of sludge flocs.

An Occlusion-Robust Feature Selection Framework in Pedestrian Detection †.

Better features have been driving the progress of pedestrian detection over the past years. However, as features become richer and higher dimensional, noise and redundancy in the feature sets become bigger problems. These problems slow down learning and can even reduce the performance of the learned model. Current solutions typically exploit dimension reduction techniques. In this paper, we propose a simple but effective feature selection framework for pedestrian detection. Moreover, we introduce occluded pedestrian samples into the training process and combine it with a new feature selection criterion, which enables improved performances for occlusion handling problems. Experimental results on the Caltech Pedestrian dataset demonstrate the efficiency of our method over the state-of-art methods, especially for the occluded pedestrians.

Plasmonic waveguide with folded stubs for highly confined terahertz propagation and concentration.

We proposed a novel planar terahertz (THz) plasmonic waveguide with folded stub arrays to achieve excellent terahertz propagation performance with tight field confinement and compact size based on the concept of spoof surface plasmon polaritons (spoof SPPs). It is found that the waveguide propagation characteristics can be directly manipulated by increasing the length of the folded stubs without increasing its lateral dimension, which exhibits much lower asymptotic frequency of the dispersion relation and even tighter terahertz field confinement than conventional plasmonic waveguides with rectangular stub arrays. Based on this waveguiding scheme, a terahertz concentrator with gradual step-length folded stubs is proposed to achieve high terahertz field enhancement, and an enhancement factor greater than 20 is demonstrated. This work offers a new perspective on very confined terahertz propagation and concentration, which may have promising potential applications in various integrated terahertz plasmonic circuits and devices, terahertz sensing and terahertz nonlinear optics.

Long-term effects of exercise therapy versus arthroscopic partial meniscectomy for degenerative meniscal tear: A meta-analysis of randomized controlled trials.

BACKGROUND: Degenerative meniscal tear (DMT) is common in the elderly population. However, there has been controversy over the treatment of DMT regarding whether to adopt arthroscopic partial meniscectomy (APM) or exercise therapy (ET). In order to compare the long-term outcomes between the two treatment methods, we conducted a meta-analysis of randomized controlled trials (RCTs) with long-term follow-up. METHODS: PubMed, Cochrane Library, Embase, and Web of Science were last searched on 16 April 2023 for studies on DMT that compared the clinical outcomes between APM and ET. The subjective outcomes of the comparison include the Knee Injury and Osteoarthritis Outcome Score (KOOS), which consists of five sub-scales: pain, symptoms, activities of daily living (ADL), sport and recreation (Sport/recreation), and quality of life (QOL). The objective outcome includes knee osteoarthritis progression. RESULTS: We identified 6 potentially eligible trials, including 1078 participants, from the literature search. ET showed a lower risk of knee osteoarthritis progression than APM (RR, 1·27; 95%CI 1·05 to 1·53). There were no statistically significant differences in the KOOS-pain, KOOS-symptoms, KOOS-ADL, KOOS-Sport/recreation, and KOOS-QOL between the two treatment methods. CONCLUSION: For the treatment of DMT, ET showed a lower risk of knee osteoarthritis progression than APM. ET and APM had comparable effects on subjective outcomes including pain management and knee function. Therefore, it is not recommended to use APM but rather recommended to use ET for treating APM.

Physeal-Sparing, All-Inside Anterior Cruciate Ligament Reconstruction Using Quadrupled Semitendinosus Autograft and Suture Tape Augmentation for Skeletally Immature Patients.

The anterior cruciate ligament (ACL) is the primary soft-tissue structure for anterior stabilization of the knee and is one of the most frequently injured structures. The incidence of ACL injuries in children and adolescents ranges from 92 to 151 per 100,000 person-years. The choice of surgical treatment for this population group is controversial, with a widespread concern that adult reconstruction techniques may damage the epiphyseal plate, compromise growth, or cause deformity. In this article, we describe a physeal-sparing, all-inside ACL reconstruction technique for skeletally immature patients. This technique is supported by retrograde drilling of the femoral tunnel and retrograde drilling of the tibial tunnel, both of which are able to avoid the epiphyseal growth line. Fixation of the quadrupled semitendinosus autograft and suture tape augmentation are achieved by soft-tissue buttons on the femur and tibia. The surgical details of this reproducible reconstruction technique are elaborated.

Evaluation of ChatGPT in providing appropriate fracture prevention recommendations and medical science question responses: A quantitative research.

Currently, there are limited studies assessing ChatGPT ability to provide appropriate responses to medical questions. Our study aims to evaluate ChatGPT adequacy in responding to questions regarding osteoporotic fracture prevention and medical science. We created a list of 25 questions based on the guidelines and our clinical experience. Additionally, we included 11 medical science questions from the journal Science. Three patients, 3 non-medical professionals, 3 specialist doctor and 3 scientists were involved to evaluate the accuracy and appropriateness of responses by ChatGPT3.5 on October 2, 2023. To simulate a consultation, an inquirer (either a patient or non-medical professional) would send their questions to a consultant (specialist doctor or scientist) via a website. The consultant would forward the questions to ChatGPT for answers, which would then be evaluated for accuracy and appropriateness by the consultant before being sent back to the inquirer via the website for further review. The primary outcome is the appropriate, inappropriate, and unreliable rate of ChatGPT responses as evaluated separately by the inquirer and consultant groups. Compared to orthopedic clinicians, the patients' rating on the appropriateness of ChatGPT responses to the questions about osteoporotic fracture prevention was slightly higher, although the difference was not statistically significant (88% vs 80%, P = .70). For medical science questions, non-medical professionals and medical scientists rated similarly. In addition, the experts' ratings on the appropriateness of ChatGPT responses to osteoporotic fracture prevention and to medical science questions were comparable. On the other hand, the patients perceived that the appropriateness of ChatGPT responses to osteoporotic fracture prevention questions was slightly higher than that to medical science questions (88% vs 72·7%, P = .34). ChatGPT is capable of providing comparable and appropriate responses to medical science questions, as well as to fracture prevention related issues. Both the inquirers seeking advice and the consultants providing advice recognize ChatGPT expertise in these areas.

Appropriate thromboprophylaxis strategy for COVID-19 patients on dosage, antiplatelet therapy, outpatient, and postdischarge prophylaxis: a meta-analysis of randomized controlled trials.

BACKGROUND: There was controversy surrounding the optimal thromboprophylaxis strategy for coronavirus disease 2019 (COVID-19) patients. This included debates on the dosage of anticoagulants for thromboembolism prophylaxis, the requirement for additional antiplatelet therapy, and the necessity of prophylaxis for outpatients and postdischarge. To explore this, the authors performed a meta-analysis of randomized controlled trials. METHODS: PubMed, Cochrane Library, Embase, and Web of Science were last searched on 26 July 2023 for studies comparing the effect of different dose of anticoagulation, additional antiplatelet, and postdischarge prophylaxis for COVID-19 patients. The results of eligible studies were analyzed in terms of thromboembolism events, major bleeding and all-cause mortality during follow-up. RESULTS: Our study included a total of 25 randomized controlled trials, involving 17 911 patients. Our results revealed that, compared to prophylactic dose, therapeutic dose showed lower thrombotic risk (RR, 0.66; 95% CI: 0.45-0.96) but had similar major bleeding risk for critically ill patients with COVID-19. On the other hand, intermediate dose and prophylactic dose demonstrated similar thromboembolism risk and major bleeding risk. For noncritically ill patients with COVID-19, therapeutic dose of anticoagulants was associated with lower thrombotic risk (RR, 0.50; 95% CI: 0.34-0.72) but, at the same time, increased the risk of major bleeding (RR, 2.01; 95% CI: 1.22-3.33). However, intermediate dose showed lower thromboembolism risk (RR, 0.38; 95% CI: 0.21-0.69) while maintaining a similar major bleeding risk. In critically ill patients, additional antiplatelet therapy showed similar thromboembolism, major bleeding risk, and mortality when compared to no treatment. For outpatients, additional prophylactic anticoagulation showed similar thromboembolism, major bleeding risk, and mortality when compared to no treatment. For postdischarge patients, postdischarge prophylaxis reduced thromboembolism risk (RR, 0.49; 95% CI: 0.31-0.76) but increased major bleeding risk (RR, 2.63; 95% CI: 1.13-6.14). CONCLUSION: For noncritically ill patients, therapeutic dose prophylactic anticoagulation significantly reduced venous thromboembolism but increases major bleeding risk. Intermediate dose effectively lowered venous thromboembolism without raising major bleeding risk. The optimal dose and need for additional antiplatelet therapy in critically ill patients, as well as the necessity of prophylactic anticoagulation in outpatient and postdischarge patients, required further investigation and confirmation through rigorous evidence studies.

Similar outcomes between arthroscopic capsular release and manipulation under anaesthesia for frozen shoulder: A meta-analysis.

To compared the arthroscopic capsular release (ACR) with manipulation under anaesthesia (MUA) for the surgical treatment of frozen shoulder (FS) based on postoperative outcomes and complications. PubMed, Cochrane Library, Embase, and Web of Science were searched on October 2, 2023 to retrieve eligible studies that compared ACR with MUA in terms of clinical outcomes (pain visual analogue scale, external rotation, forward flexion and adverse events) for patients with FS. Mean differences (MD) were calculated for continuous outcomes and odds ratios (OR) were calculated for dichotomous outcomes. Six papers, including 5 clinical studies (a total of 690 shoulders), were included in the final meta-analysis. The forward flexion was found to be larger in the ACR group at 3 months (MD, 2.73; 95%CI, 0.42-5.04; I2 = 44%; P = 0.02) and 6 months (MD, 2.36; 95%CI, 1.29-3.44; I2 = 0%; P < 0.0001). Except for this, ACR was comparable with MUA in terms of pain visual analogue scale at 3, 6 and 12 months (p = 0.25, p = 0.11, p = 0.28, respectively), external rotation at 3, 6 and 12 months (p = 0.15, p = 0.52, p = 0.23, respectively), and forward flexion at 12 months (p = 0.08). There were no differences in complication rates between the two groups (OR, 0.82; 95%CI, 0.47-1.44; I2 = 0%; P = 0.50). In comparison with MUA, ACR demonstrated better outcomes for forward flexion at 3 and 6 months, while there were no significant differences between ACR and MUA in terms of pain visual analogue scale, external rotation and adverse events.

Intensive or liberal glucose control in intensive care units for septic patients? A meta-analysis of randomized controlled trials.

OBJECTIVE: To compare the clinical outcomes of intensive glucose control and liberal glucose control for septic patients in intensive care unit. METHODS: The databases of PubMed, Cochrane Library, Embase and Web of Science were searched systematically from inception to November 27, 2023 to identify trials involving a randomized comparison between intensive and liberal glucose control for septic patients in intensive care unit. RESULTS: A total of 14 randomized controlled trials involving 6226 patients were finally included. There was no statistically significant difference observed between intensive glucose control and liberal glucose control in terms of all-cause mortality, the need for renal replacement, vasopressor-free and mechanical ventilation-free days, and length of hospital stay. However, it is noteworthy that intensive glucose control exhibited a statistically higher risk of severe hypoglycemia (RR 2.66; 95%CI 1.85 to 3.83), need for blood transfusion (RR 1.12; 95%CI 1.01 to 1.23), and statistically prolonged length of stay in the ICU (MD 1.67; 95%CI 0.22 to 3.12) compared to liberal glucose control. Nevertheless, sensitivity analysis revealed that the need for blood transfusion and length of stay in the intensive care unit were not robust. CONCLUSIONS: Both intensive and liberal glucose control had comparable effects on improving patient outcomes, but intensive glucose control carried a higher risk of severe hypoglycemia.

Preferences in anterior cruciate ligament reconstruction: A survey among orthopedic surgeons in China.

The purpose of this study was to reveal the current trends and preferences of Chinese orthopedic surgeons regarding anterior cruciate ligament (ACL) reconstruction through a nationwide web-based survey conducted in China. The survey questionnaire was distributed via WeChat to the chairmen of provincial orthopedic and sports medicine organizing committees in China, who then shared it in their respective WeChat workgroups. The questionnaire consisted of 52 multiple-choice questions covering 8 sections. Data collection was implemented by Questionnaire Star. A total of 812 valid questionnaires were returned: 94.21% of the respondents preferred single-bundle reconstruction of ACL, while 61.70% preferred autogenous semitendinosus plus gracilis reconstruction; 76.35% of the respondents preferred establishing the femoral tunnel first, while 47.29% preferred establishing the femoral tunnel through a medial auxiliary approach; and 85.10% of the respondents recommended patients to undergo surgery within 3 months after ligament injury. Besides, the vast majority of respondents chose to retain the ligamentous remnant bundle (92.98%) and recommended routine use of knee braces postoperatively (94.09%). It is recommended to perform arthroscopic single-bundle ACL reconstruction with the remnant preserving technique using a hamstring autograft within 3 months of ACL rupture, with support of postoperative functional braces.

Interposition Grafting Using Fascia Lata Autograft for Failed Rotator Cuff Repairs.

Massive rotator cuff tears are a huge challenge for orthopaedic surgeons, as the patients may be in need of multiple operations, even including reverse total shoulder arthroplasty. The various repair methods for the rotator cuff, such as partial rotator cuff repair, patch-augmented rotator cuff repair, bridging rotator cuff reconstruction with graft interposition, tendon transfer, and superior capsular reconstruction, have always been the focus of research. During surgical intervention for failed rotator cuff repairs, complexity of tears, poor tissue quality, retained hardware, and adhesions are the problems routinely encountered. In this Technical Note, we describe the technique of interposition grafting using fascia lata autograft to reconstruct the rotator cuff after failed primary repair.

Anterior Shoulder Stabilization Using Single Needle-Assisted Outside-In Remplissage Technique and Bankart Repair.

Arthroscopic repair of Bankart injury is the first choice for the treatment of anterior shoulder instability. How to avoid recurring shoulder joint dislocation is a challenge, especially when combined with Hill-Sachs lesions. The arthroscopy technology allows for broader vision and less surgical trauma but is limited by a smaller operating space. At present, extensive descriptions about the surgical procedure of arthroscopic Bankart repair have been published. In this Technical Note, we describe the use of remplissage filling with Hill-Sachs lesion combined with Bankart repair to further improve the surgical accuracy and clinical efficacy. In particular, the application of single needle-assisted outside-in remplissage technique and Bankart repair is introduced in detail.