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BACKGROUND: Major Depressive Disorder (MDD) affects 350 million people worldwide. Electroconvulsive therapy (ECT) is effective, yet research on cognitive assessments post-treatment is lacking. This study systematically reviews and meta-analyzes the effectiveness of cognitive assessment tools post-ECT to optimize MDD treatment. METHODS: Following PRISMA guidelines, this review was pre-registered on PROSPERO (CRD42023470318). Searches were conducted across nine databases up to November 12, 2023. Quality assessment for Randomized Controlled Trials (RCTs) and quasi-experimental studies was performed using the Cochrane risk of bias tool, JBI critical appraisal tools, and the Jadad scale. Meta-analyses for short-term and long-term cognitive function involved 24 and 18 tools, respectively. FINDINGS: Thirty studies (20 RCTs and 10 quasi-experimental) involving 2462 MDD patients were evaluated. Results indicated no significant differences in overall short-term and long-term cognitive functions post-ECT. Short-term analysis showed impairments in memory, learning, and verbal abilities but improvements in attention and processing speed. Long-term analysis revealed enhancements in memory, learning, verbal, and visuospatial abilities compared to baseline. Based on GRADE classification, we recommend 11 tools for assessing acute cognitive function and 10 tools for chronic cognitive impairment. These tools demonstrated high reliability and validity, supporting their clinical use. INTERPRETATION: These findings provide critical evidence for future ECT clinical guidelines in managing MDD. The recommended tools can aid clinicians in adjusting ECT regimens, identifying early cognitive changes, and improving therapeutic outcomes in MDD treatment.
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Objectives: To explore the therapeutic effects of M2 macrophages in diabetic nephropathy (DN) and their mechanism.Methods: We infused M2 macrophages stimulated with IL-4 into 10-week-old db/db mice once a week for 4 weeks through the tail vein as M2 group. Then we investigated the role of M2 macrophages in alleviating the infammation of DN and explored the mechanism.Results: M2 macrophages hindered the progression of DN, reduced the levels of IL-1ß (DN group was 34%, M2 group was 13%, p < 0.01) and MCP-1 (DN group was 49%, M2 group was 16%, p < 0.01) in the glomeruli. It was also proven that M2 macrophages alleviate mesangial cell injury caused by a high glucose environment. M2 macrophage tracking showed that the infused M2 macrophages migrated to the kidney, and the number of M2 macrophages in the kidney reached a maximum on day 3. Moreover, the ratio of M2 to M1 macrophages was 2.3 in the M2 infusion group, while 0.4 in the DN group (p < 0.01). Mechanistically, M2 macrophages downregulated Janus kinase (JAK) 2 and signal transducer and activator of transcription (STAT) 3 in mesangial cells.Conclusions: Multiple infusions of M2 macrophages significantly alleviated inflammation in the kidney and hindered the progression of DN at least partially by abrogating the M1/M2 homeostasis disturbances and suppressing the JAK2/STAT3 pathway in glomerular mesangial cells. M2 macrophage infusion may be a new therapeutic strategy for DN treatment.
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Nefropatias Diabéticas , Janus Quinase 2 , Macrófagos , Fator de Transcrição STAT3 , Transdução de Sinais , Animais , Janus Quinase 2/metabolismo , Nefropatias Diabéticas/metabolismo , Fator de Transcrição STAT3/metabolismo , Camundongos , Macrófagos/metabolismo , Masculino , Células Mesangiais/metabolismo , Modelos Animais de Doenças , Glomérulos Renais/patologia , Glomérulos Renais/metabolismo , Quimiocina CCL2/metabolismo , Camundongos Endogâmicos C57BL , Interleucina-1beta/metabolismoRESUMO
Three-dimensional (3D) phenotyping is important for studying plant structure and function. Light detection and ranging (LiDAR) has gained prominence in 3D plant phenotyping due to its ability to collect 3D point clouds. However, organ-level branch detection remains challenging due to small targets, sparse points, and low signal-to-noise ratios. In addition, extracting biologically relevant angle traits is difficult. In this study, we developed a stratified, clustered, and growing-based algorithm (SCAG) for soybean branch detection and branch angle calculation from LiDAR data, which is heuristic, open-source, and expandable. SCAG achieved high branch detection accuracy (F-score = 0.77) and branch angle calculation accuracy (r = 0.84) when evaluated on 152 diverse soybean varieties. Meanwhile, the SCAG outperformed 2 other classic algorithms, the support vector machine (F-score = 0.53) and density-based methods (F-score = 0.55). Moreover, after applying the SCAG to 405 soybean varieties over 2 consecutive years, we quantified various 3D traits, including canopy width, height, stem length, and average angle. After data filtering, we identified novel heritable and repeatable traits for evaluating soybean density tolerance potential, such as the ratio of average angle to height and the ratio of average angle to stem length, which showed greater potential than the well-known ratio of canopy width to height trait. Our work demonstrates remarkable advances in 3D phenotyping and plant architecture screening. The algorithm can be applied to other crops, such as maize and tomato. Our dataset, scripts, and software are public, which can further benefit the plant science community by enhancing plant architecture characterization and ideal variety selection.
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Piezoelectric nanogenerators (PENGs) are booming for energy collection and wearable energy supply as one of the next generations of green energy-harvesting devices. Balancing the output, safety, degradation, and cost is the key to solving the bottleneck of PENG application. In this regard, yttrium (Y)-doped zinc oxide (ZnO) (Y-ZnO) was synthesized and embedded into polylactide (PLLA) for developing degradable piezoelectric composite films with an enhanced energy-harvesting performance. The synthesized Y-ZnO exhibits high piezoelectric properties benefiting from the stronger polarity of the Y-O bond and regulation of oxygen vacancy concentration, which improve the output performance of the composite film with Y-ZnO and PLLA (Y-Z-PLLA). The obtained open-circuit voltage (Voc), short-circuit current (Isc), and instantaneous power density of the optimized Y-Z-PLLA PENG reach 17.52 V, 2.45 µA, and 1.76 µW/cm2, respectively. The proposed PENG also shows good degradability. In addition, practical applications of the proposed PENG were demonstrated by converting biomechanical energy, such as walking, running, and jumping, into electricity.
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BACKGROUND: Treatment-Resistant Depression (TRD) challenges psychiatric treatment, with existing guidelines covering only a subset of augmentation strategies. METHODS: A network meta-analysis following PRISMA guidelines examined the efficacy and safety of TRD treatments, analyzing 72 randomized controlled trials from eight databases, assessing response and remission rates, tolerability, and safety through the Cochrane Risk of Bias Tool and CINeMA framework. FINDINGS: Including 12,105 participants, the analysis highlighted ECT, Ketamine, Esketamine, and Psilocybin as superior first-line treatments due to their optimal balance between effectiveness and tolerability. Brexpiprazole and Quetiapine showed no significant efficacy over placebo in response rates, while Esketamine and Psilocybin exhibited lower tolerability. INTERPRETATION: The results advocate for ECT, Ketamine, Esketamine, and Psilocybin as preferred treatments for TRD, guiding clinical practice with evidence-based recommendations for enhancing treatment outcomes. This study underscores the importance of considering both efficacy and safety in selecting augmentation strategies for TRD.
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Transtorno Depressivo Resistente a Tratamento , Metanálise em Rede , Ensaios Clínicos Controlados Aleatórios como Assunto , Humanos , Transtorno Depressivo Resistente a Tratamento/tratamento farmacológico , Transtorno Depressivo Resistente a Tratamento/terapia , Antidepressivos/uso terapêutico , Eletroconvulsoterapia , Ketamina/uso terapêutico , Psilocibina/uso terapêutico , Psilocibina/farmacologia , Psilocibina/efeitos adversos , Avaliação de Resultados em Cuidados de SaúdeRESUMO
Forest canopy structural complexity (CSC) plays a crucial role in shaping forest ecosystem productivity and stability, but the precise nature of their relationships remains controversial. Here, we mapped the global distribution of forest CSC and revealed the factors influencing its distribution using worldwide light detection and ranging data. We find that forest CSC predominantly demonstrates significant positive relationships with forest ecosystem productivity and stability globally, although substantial variations exist among forest ecoregions. The effects of forest CSC on productivity and stability are the balanced results of biodiversity and resource availability, providing valuable insights for comprehending forest ecosystem functions. Managed forests are found to have lower CSC but more potent enhancing effects of forest CSC on ecosystem productivity and stability than intact forests, highlighting the urgent need to integrate forest CSC into the development of forest management plans for effective climate change mitigation.
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Biodiversidade , Mudança Climática , Ecossistema , Florestas , Conservação dos Recursos Naturais , Árvores/crescimento & desenvolvimentoRESUMO
China's extensive planted forests play a crucial role in carbon storage, vital for climate change mitigation. However, the complex spatiotemporal dynamics of China's planted forest area and its carbon storage remain uncaptured. Here we reveal such changes in China's planted forests from 1990 to 2020 using satellite and field data. Results show a doubling of planted forest area, a trend that intensified post-2000. These changes lead to China's planted forest carbon storage increasing from 675.6 ± 12.5 Tg C in 1990 to 1,873.1 ± 16.2 Tg C in 2020, with an average rate of ~ 40 Tg C yr-1. The area expansion of planted forests contributed ~ 53% (637.2 ± 5.4 Tg C) of the total above increased carbon storage in planted forests compared with planted forest growth. This proactive policy-driven expansion of planted forests has catalyzed a swift increase in carbon storage, aligning with China's Carbon Neutrality Target for 2060.
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Several decades of heterochronic parabiosis (HCPB) studies have demonstrated the restorative impact of young blood, and deleterious influence of aged blood, on physiological function and homeostasis across tissues, although few of the factors responsible for these observations have been identified. Here we develop an in vitro HCPB system to identify these circulating factors, using replicative lifespan (RLS) of primary human fibroblasts as an endpoint of cellular health. We find that RLS is inversely correlated with serum donor age and sensitive to the presence or absence of specific serum components. Through in vitro HCPB, we identify the secreted protein pigment epithelium-derived factor (PEDF) as a circulating factor that extends RLS of primary human fibroblasts and declines with age in mammals. Systemic administration of PEDF to aged mice reverses age-related functional decline and pathology across several tissues, improving cognitive function and reducing hepatic fibrosis and renal lipid accumulation. Together, our data supports PEDF as a systemic mediator of the effect of young blood on organismal health and homeostasis and establishes our in vitro HCPB system as a valuable screening platform for the identification of candidate circulating factors involved in aging and rejuvenation.
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As a milestone in the exploration of topological physics, Fermi arcs bridging Weyl points have been extensively studied. Weyl points, as are Fermi arcs, are believed to be only stable when preserving translation symmetry. However, no experimental observation of aperiodic Fermi arcs has been reported so far. Here, we continuously twist a bi-block Weyl meta-crystal and experimentally observe the twisted Fermi arc reconstruction. Although both the Weyl meta-crystals individually preserve translational symmetry, continuous twisting operation leads to the aperiodic hybridization and scattering of Fermi arcs on the interface, which is found to be determined by the singular total reflection around Weyl points. Our work unveils the aperiodic scattering of Fermi arcs and opens the door to continuously manipulating Fermi arcs.
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Background: Pituitary stalk interruption syndrome (PSIS) is a complex clinical syndrome characterized by varied pituitary hormone deficiencies, leading to severe manifestations across multiple systems. These include lifelong infertility, short stature, mental retardation, and potentially life-threatening pituitary crises if not promptly diagnosed and treated. Despite extensive research, the precise pathogenesis of PSIS remains unclear. Currently, there are two proposed theories regarding the pathogenic mechanisms: the genetic defect theory and the perinatal injury theory. Methods: We systematically searched English databases (PubMed, Web of Science, Embase) and Chinese databases (CNKI, WanFang Med Online, Sinomed) up to February 24, 2023, to summarize studies on gene sequencing in PSIS patients. Enrichment analyses of reported mutated genes were subsequently performed using the Metascape platform. Results: Our study included 37 articles. KEGG enrichment analysis revealed mutated genes were enriched in the Notch signaling pathway, Wnt signaling pathway, and Hedgehog signaling pathway. GO enrichment analysis demonstrated mutated genes were enriched in biological processes such as embryonic development, brain development, axon development and guidance, and development of other organs. Conclusion: Based on our summary and analyses, we propose a new hypothesis: disruptions in normal embryonic development, partially stemming from the genetic background and/or specific gene mutations in individuals, may increase the likelihood of abnormal fetal deliveries, where different degrees of traction during delivery may lead to different levels of pituitary stalk interruption and posterior lobe ectopia. The clinical diversity observed in PSIS patients may result from a combination of genetic background, specific mutations, and variable degrees of traction during delivery.
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Hipopituitarismo , Doenças da Hipófise , Humanos , Proteínas Hedgehog , Doenças da Hipófise/patologia , Hipófise/patologia , Hipopituitarismo/genética , Hipopituitarismo/patologia , Mutação , SíndromeRESUMO
Objective: To compare the diagnostic value of adrenocorticotropic hormone (ACTH) stimulation test (AST) with different doses of ACTH combined with midnight administration of 1 mg dexamethasone for the determination of the subtypes of primary hyperaldosteronism (PA). Methods: This is a prospective observational study. Patients diagnosed with PA in the Department of Endocrinology, the First Medical Center of of Chinese PLA General Hospital from January 1, 2020 to September 30, 2022 underwent AST with different doses of ACTH. All patients received 1 mg dexamethasone at midnight for inhibition. Then, the patients were randomly assigned to 25-unit and 50-unit ACTH treatment groups by a ratio of 1:2. Subtype classification and diagnosis of aldosterone-producing adenoma (APA) and idiopathic hyperaldosteronism (IHA) was made on the basis of adrenal venous blood samples and/or postoperative pathology and clinical follow-up findings. Receiver operating characteristics (ROC) curves were plotted to examine the diagnostic efficacy and the difference of AST by varying doses of ACTH in distinguishing APA and IHA. Results: A total of 82 patients, including 49 patients with APA (59.8%) and 33 patients with IHA (40.2%), were enrolled. There were 29 patients in the 25-unit ACTH group (35.4%) and 53 patients in the 50-unit ACTH group (64.6%). There were no significant differences in age, sex, blood pressure, minimum serum potassium, and biochemical parameters between the 25-unit and 50-unit groups. After ACTH stimulation, plasma aldosterone concentration (PAC), cortisol (F), and PAC/F at different points of time showed no statistical difference between the two groups (P>0.05). The area under the curve (AUC) of PAC in the 25-unit group was higher than that of PAC/F. The AUC of PAC reached the maximum at 90 minutes (0.948, 95% confidence interval [CI]: 0870-1.000) and the optimal cutoff was 38.0 ng/dL, which had a sensitivity of 92.9% and a specificity of 86.7% for differentiating APA and IHA. Similar to the 25-unit group, the maximum AUC of PAC in the 50-unit group was greater than that of PAC/F. The AUC of PAC reached the maximum 90 minutes (0.930, 95% CI: 0.840-0.994) and the optimal cutoff was 39.6 ng/dL, which had a sensitivity of 91.2% and a specificity of 83.3%. The AUC of PAC at different points of time in the 25-unit ACTH group (0.862-0.948) was greater than that of 50-unit ACTH group (0.823-0.930), but the difference was not statistical significance. Conclusion: AST with 25-unit or 50-unit ACTH combined with small-dose dexamethasone can be used in PA subtype determination, ie, differentiation between APA and IHA. The optimal PAC cut-off values for 25-unit or 50-unit ACTH are similar, being 38.0 ng/dL and 39.6 ng/dL, respectively, and both cutoff values show higher sensitivity and specificity at 90 min. The AST with 25-unit ACTH has the smaller dose and the better safety. Therefore, it is recommended for the diagnosis of PA subtypes.
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Hormônio Adrenocorticotrópico , Hiperaldosteronismo , Hipertensão , Humanos , Hormônio Adrenocorticotrópico/administração & dosagem , Aldosterona , Dexametasona , Hiperaldosteronismo/diagnóstico , Sensibilidade e EspecificidadeRESUMO
Both domestic and non-domestic cats are now established to be susceptible to infection by SARS-CoV-2, the cause of the ongoing COVID-19 pandemic. While serious disease in cats may occur in some instances, the majority of infections appear to be subclinical. Differing prevalence data for SARS-CoV-2 infection of cats have been reported, and are highly context-dependent. Here, we report a retrospective serological survey of cats presented to an animal practice in New York City, located in close proximity to a large medical center that treated the first wave of COVID-19 patients in the US in the Spring of 2020. We sampled 79, mostly indoor, cats between June 2020 to May 2021, the early part of which time the community was under a strict public health "lock-down". Using a highly sensitive and specific fluorescent bead-based multiplex assay, we found an overall prevalence of 13/79 (16%) serologically-positive animals for the study period; however, cats sampled in the Fall of 2020 had a confirmed positive prevalence of 44%. For SARS-CoV-2 seropositive cats, we performed viral neutralization test with live SARS-CoV-2 to additionally confirm presence of SARS-CoV-2 specific antibodies. Of the thirteen seropositive cats, 7/13 (54%) were also positive by virus neutralization, and 2 of seropositive cats had previously documented respiratory signs, with high neutralization titers of 1:1024 and 1:4096; overall however, there was no statistically significant association of SARS-CoV-2 seropositivity with respiratory signs, or with breed, sex or age of the animals. Follow up sampling of cats, while limited in scope, showed that positive serological titers were maintained over time. In comparison, we found an overall confirmed positive prevalence of 51% for feline coronavirus (FCoV), an endemic virus of cats, with 30% confirmed negative for FCoV. We demonstrate the impact of SARS-CoV in a defined feline population during the first wave of SARS-CoV-2 infection of humans, and suggest that human-cat transmission was substantial in our study group. Our data provide a new context for SARS-CoV-2 transmission events across species.
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OBJECTIVES: Significant atherosclerotic stenosis or occlusion in the distal internal carotid artery (ICA) may induce diffuse wall thickening (DWT) in the upstream arterial wall. This study aimed to assess the association of atherosclerotic steno-occlusive diseases in the distal ICA with DWT in the upstream ipsilateral ICA. METHODS: Individuals with atherosclerotic stenosis in the distal ICA, detected by carotid MR vessel wall imaging using 3D pre- and post-contrast T1 volume isotropic turbo spin-echo acquisition (T1-VISTA) sequence, were enrolled. The associations of vessel wall thickening, the longitudinal extent of DWT, enhancement of the upstream ipsilateral ICA, and stenosis degree in the distal ICA were examined. RESULTS: Totally 64 arteries in 55 patients with atherosclerotic steno-occlusive distal ICAs were included. Significant correlations were found between distal ICA stenosis and DWT in the petrous ICA (r = 0.422, p = 0.001), DWT severity (r = 0.474, p < 0.001), the longitudinal extent of DWT in the ICA (r = 0.671, p < 0.001), enhancement in the petrous ICA (r = 0.409, p = 0.001), and enhancement degree (r = 0.651, p < 0.001). In addition, high degree of enhancement was correlated with both increased wall thickness and increased prevalence of DWT in the petrous ICA (both p < 0.001). CONCLUSIONS: DWT of the petrous ICA is commonly detected in patients with atherosclerotic steno-occlusive disease in the distal ICA. The degree of stenosis in the distal ICA is associated with wall thickening and its longitudinal extent in the upstream segments. CLINICAL RELEVANCE STATEMENT: Diffuse wall thickening is a common secondary change in atherosclerotic steno-occlusive disease in the intracranial carotid. This phenomenon constitutes a confounding factor in the distinction between atherosclerosis and inflammatory vasculopathies, and could be reversed after alleviated atherosclerotic stenosis. KEY POINTS: ⢠Diffuse wall thickening of the petrous internal carotid artery is commonly detected in patients with atherosclerotic steno-occlusive disease in the distal internal carotid artery. ⢠The phenomenon of diffuse wall thickening could be reversed after stenosis alleviation. ⢠Carotid artery atherosclerosis with diffuse wall thickening should warrant a differential diagnosis from other steno-occlusive diseases, including moyamoya diseases and Takayasu aortitis.
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Artéria Carótida Interna , Estenose das Carótidas , Humanos , Feminino , Masculino , Estenose das Carótidas/diagnóstico por imagem , Estenose das Carótidas/complicações , Pessoa de Meia-Idade , Artéria Carótida Interna/diagnóstico por imagem , Artéria Carótida Interna/patologia , Idoso , Angiografia por Ressonância Magnética/métodos , Adulto , Imageamento Tridimensional/métodos , Idoso de 80 Anos ou maisRESUMO
OBJECTIVE: Electroconvulsive therapy (ECT) is endorsed as a principal treatment approach for major depressive disorder (MDD) worldwide. Despite prior studies highlighting potential short-term cognitive deficits post-ECT, the debate regarding its long-term implications persists. This study endeavors to elucidate the reasons for this contention using an evidence-based approach. METHODS: This investigation, meticulously aligned with PRISMA guidelines, was prospectively enlisted on PROSPERO (CRD42023439259). A comprehensive search was performed across various databases, including PubMed, Cochrane Library, Web of Science, Embase, SCOPUS, PsycINFO, CINAHL Plus, and OpenGrey. This review, traversing the literature from inception until June 2023, encapsulated 10 studies (five RCTs and five quasi-experimental studies) involving a cohort of 868 individuals diagnosed with major depressive disorder. RESULTS: The meta-analysis revealed that the persistent discourse on ECT-induced long-term cognitive impairment chiefly emanates from the inadequacies in the specificity and sensitivity of conventional assessment instruments. Conversely, subgroup analyses showed that cognitive impairment in ECT, as gauged by the nascent assessment tool, Electroconvulsive Therapy Cognitive Assessment (ECCA) (SMD = -0.94, 95 % CI [-1.33, -0.54], p < 0.00001), exerted a detrimental influence on the long-term trajectory of individuals with MDD. Notably, there was an adverse effect of ECT on the subdomain of long-term learning cognitive abilities in patients with MDD (SMD = -0.37, 95 % CI [-0.55, -0.18], p < 0.0001). Contrarily, memory (SMD = 0.16, 95 % CI [-0.02, 0.34], p = 0.08), attention (SMD = 0.23, 95 % CI [-0.07, 0.54], p = 0.14), language (SMD = -0.10, 95 % CI [-0.25, 0.05], p = 0.19), spatial perception, and orientation (SMD = -0.04, 95 % CI [-0.28, 0.20], p = 0.75) exhibited no significant detriments. Intriguingly, ECT showed favorable effects on executive function and processing speed among patients with MDD (SMD = 0.52, 95 % CI [0.29, 0.74], p < 0.00001). CONCLUSION: This meta-analysis underscores ECCA's superior sensitivity of the ECCA compared to the MMSE or MoCA in detecting cognitive changes in patients with post-ECT MDD. Following Electroconvulsive Therapy (ECT), deterioration was observed in overall cognitive function and learning capabilities, while memory, attention, language, and spatial perception remained stable. Notably, enhancements were discerned in executive function and processing speed, which not only augmented academic perspectives but also steered the formulation of international clinical guidelines, accentuating the progressive role of ECT in the therapeutic approach to MDD.
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Disfunção Cognitiva , Transtorno Depressivo Maior , Eletroconvulsoterapia , Humanos , Cognição , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/terapia , Transtorno Depressivo Maior/terapia , Transtorno Depressivo Maior/psicologia , Eletroconvulsoterapia/efeitos adversos , Função ExecutivaRESUMO
Deep learning has been attracting more and more attention in the phase unwrapping of fringe projection profilometry (FPP) in recent years. In order to improve the accuracy of the deep-learning-based unwrapped phase methods from a single fringe pattern, this paper proposes a single-input triple-output neural network structure with a physical prior. In the proposed network, a single-input triple-output network structure is developed to convert the input fringe pattern into three intermediate outputs: the wrapped phase, the fringe order, the coarse unwrapped phase, and the final output high-precision unwrapped phase from the three outputs. Moreover, a new, to the best of our knowledge, loss function is designed to improve the performance of the model using a physical prior about these three outputs in FPP. Numerous experiments demonstrated that the proposed network is able to improve the accuracy of the unwrapped phase, which can also be extended to other deep learning phase unwrapping models.
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Nanofibers are an emerging kind of nano-material, widely used in several application domains such as biomedicine, high-efficiency filtration media, precision electronics, and optical devices. Centrifugal spinning, which is a novel nanofiber production technology, has been widely studied. This paper proposes a structural parameter optimization design method of a bent-tube nozzle. The mathematical model of the spinning solution motion in the nozzle is first developed. The optimization function of the structure parameters of the bent-tube nozzle is then obtained by calculation. Afterwards, these parameters are optimized using a neural network algorithm. The obtained results show that, when the bending angle is 15°, the curvature radius is 10 mm, the outlet radius is 0.205 mm, and the head loss of the solution can be minimized. Finally, centrifugal spinning experiments are conducted and the influence of the centrifugal spinning parameters on the nanofibers is analyzed. In addition, the optimized bent-tube nozzle improves the surface morphology of the nanofibers as their diameter distribution becomes more uniform.
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Increasing drought frequency and severity in a warming climate threaten forest ecosystems with widespread tree deaths. Canopy structure is important in regulating tree mortality during drought, but how it functions remains controversial. Here, we show that the interplay between tree size and forest structure explains drought-induced tree mortality during the 2012-2016 California drought. Through an analysis of over one million trees, we find that tree mortality rate follows a "negative-positive-negative" piecewise relationship with tree height, and maintains a consistent negative relationship with neighborhood canopy structure (a measure of tree competition). Trees overshadowed by tall neighboring trees experienced lower mortality, likely due to reduced exposure to solar radiation load and lower water demand from evapotranspiration. Our findings demonstrate the significance of neighborhood canopy structure in influencing tree mortality and suggest that re-establishing heterogeneity in canopy structure could improve drought resiliency. Our study also indicates the potential of advances in remote-sensing technologies for silvicultural design, supporting the transition to multi-benefit forest management.
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Ecossistema , Árvores , Árvores/fisiologia , Secas , Florestas , ÁguaRESUMO
A novel method for the generation of an optical frequency comb (OFC) is presented. The proposed approach uses a laser diode with optical feedback and operating at a specific nonlinear dynamic state named periodic window. In this case, the laser spectrum exhibits a feature with a series of discrete, equally spaced frequency components, and the repetition rate can be flexibly adjusted by varying the system parameters (e.g., external cavity length), which can provide many potential applications. As an application example, a dual-OFC system for distance measurement is presented. The results demonstrate the system's ability to achieve target distance detection, underscoring its potential for real-world applications in this field.
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Based on Quantum illumination (QI) protocol, researcshers have developed prototypes of quantum radar and demonstrated its quantum enhancement. Nevertheless, there are still difficulties in the practical application for QI radar, especially the trade-off between the detection range and quantum enhancement, as well as the construction of the optimized receiver. Some studies have suggested that the potential solutions to these difficulties are to deploy the quantum limited amplifiers in QI radars, and have envisioned different amplification schemes. In this paper, we establish a universal and effective method to evaluate the signal-to-noise ratio of QI radar. It connects QI radar theory with classical radar signal processing theory, providing support for researchers to evaluate the performance of various QI radar schemes from a radar perspective. Based on this method, we prove that any quantum limited phase-insensitive amplification scheme will seriously weaken the quantum enhancement of QI radar. Furthermore, we also demonstrate that the QI radar with phase-sensitive amplified idler has no advantage over the optimal classical illumination. These results can help us avoid some unreasonable QI radar schemes. In addition, we believe that the proposed method can also be applied to explore other potential QI radar schemes and contribute to promoting the application development of QI radar.