The distinct effects of fearful and disgusting scenes on self-relevant face recognition.

Self-face recognition denotes the process by which a person can recognize their own face by distinguishing it from another's face. Although many research studies have explored the inhibition effect of negative information on self-relevant face processing, few researchers have examined whether negative scenes influence self-relevant face processing. Fearful and disgusting scenes are typical negative scenes, but little research to data has examined their discriminative effects on self-relevant face recognition. To investigate these issues, the current study explored the effect of negative scenes on self-relevant face recognition. In Study 1, 44 participants (20 men, 24 women) were asked to judge the orientation of a target face (self-face or friend-face) pictured in a negative or neutral scene, whereas 40 participants (19 men, 21 women) were asked to complete the same task in a fearful, disgusting, or neutral scene in Study 2. The results showed that negative scenes inhibited the speed of recognizing self-faces. Furthermore, the above effect of negative scenes on self-relevant face recognition occurred with fearful rather than disgusting scenes. Our findings suggest the distinct effects of fearful scenes and disgusting scenes on self-relevant face processing, which may be associated with the automatic attentional capture to negative scenes (especially fearful scenes) and the tendency to escape self-awareness.

Biomimetic Cancer-Targeting Nanoplatform Boosting AIEgens-Based Photodynamic Therapy and Ferroptosis by Disrupting Redox-Homeostasis.

Photodynamic therapy (PDT) using aggregation-induced emission photosensitizer (AIE-PS) holds tremendous potential but is limited by its inherent disadvantages and the high concentrations of reduced glutathione (GSH) in tumor cells that can neutralize ROS to weaken PDT. Herein, we designed a nanodelivery system (CM-HSADSP@[PS-Sor]) in which albumin was utilized as a carrier for hydrophobic drug AIE-PS and Sorafenib, cross-linkers with disulfide bonds were introduced to form a nanogel core, and then cancer cell membranes were wrapped on its surface to confer homologous tumor targeting ability. A two-way strategy was employed to disturb redox-homeostasis through blocking GSH synthesis by Sorafenib and consuming excess GSH via abundant disulfide bonds, thereby promoting the depletion of GSH, which in turn increased the ROS levels in cancer cells to amplify the efficacy of ferroptosis and PDT, achieving an efficient in vivo antibreast cancer effect. This study brings a new strategy for ROS-based cancer therapy and expands the application of an albumin-based drug delivery system.

New Opportunities for Electric Fields in Promoting Wound Healing: Collective Electrotaxis.

SIGNIFICANCE: It has long been hypothesized that naturally occurring electric fields (EFs) aid wound healing by guiding cell migration. Consequently, the application of EFs has significant potential for promoting wound healing. However, the mechanisms underlying the cellular response to EFs remain unclear. Recent Advances： Although the directed migration of isolated single cells under EFs has been studied for decades, only recently has experimental evidence demonstrated the distinct collective migration of large sheets of keratinocytes and corneal epithelial cells in response to applied EFs. Accumulating evidence suggests that the emergent properties of cell groups in response to EF guidance offer new opportunities for EF-assisted directional migration. CRITICAL ISSUES: In this review, we provide an overview of the field of collective electrotaxis, highlighting key advances made in recent years. We also discuss advanced engineering strategies utilized to manipulate collective electrotaxis. FUTURE DIRECTIONS: We outline a series of unanswered questions in this field and propose potential applications of collective electrotaxis in developing electrical stimulation technologies for wound healing.

Gallic Acid Attenuates Sepsis-Induced Liver Injury through C/EBPß-Dependent MAPK Signaling Pathway.

SCOPE: Liver injury is a major complication associated with sepsis. Together with others, the study has shown that gallic acid (GA) exerts anti-inflammatory and antioxidant effects in vivo. However, the role of GA in sepsis-mediated hepatic impairment and the underlying mechanisms remains to be elucidated. METHODS AND RESULTS: C57BL/6J mice are pretreated with saline or GA and subjected to sham or cecal ligation and puncture (CLP). The pathological alterations are assessed by hematoxylin and eosin staining as well as immunohistochemical staining. RNA sequencing is employed to analyze hepatic transcriptome modifications. The study finds that GA supplementation significantly ameliorates CLP-induced mortality, liver dysfunction, and inflammation. RNA sequencing reveals that 1324 genes are markedly differentially regulated in livers of saline- or GA-treated sham or CLP mice. Gene ontology analysis demonstrates that the differentially expressed genes regulated by GA are predominantly correlated with the immune system process, oxidation-reduction process, and inflammatory response. Furthermore, mitogen-activated protein kinase (MAPK) signaling is localized in the center of the GA-mediated pathway network. Notably, activation of MAPK by C16-PAF significantly blocks GA-mediated protective effects on hepatic injury, inflammation, as well as CCAAT/enhancer-binding protein-ß (C/EBPß) dependent extracellular signal-regulated kinase 1/2 (ERK1/2) and nuclear factor-κB (NF-κB) signaling. CONCLUSION: Therefore, this study indicates that GA may offer a promising therapeutic opportunity for sepsis-associated liver injury.

New horizons for the study of saffron (Crocus sativus L.) and its active ingredients in the management of neurological and psychiatric disorders: A systematic review of clinical evidence and mechanisms.

Saffron (Crocus sativus), as an herbal medicine, has been extensively investigated for treating neurological and psychiatric disorders. This systematic review aimed to assess the overall effects of saffron on cognition, depression, anxiety, sleep disorders, attention-deficit/hyperactivity disorder (ADHD), and obsessive-compulsive disorder (OCD). Relevant randomized controlled trials (RCTs) were identified by searching PubMed/Medline, Web of Science, and Clinical Trials databases up to June 2023 according to search terms and inclusion criteria. The participants were either healthy or suffering from some diseases, including neurological and psychiatric disorders, and consumed saffron or its extracts as an intervention. The risk of bias was assessed according to the Cochrane guidelines, and the PRISMA statement was followed. The meta-analysis was performed using RevMan and STATA software. A random-effects or fixed-effects model was used to calculate the pooled effect sizes. Forty-six RCTs were enrolled, and the duration of these trials ranged from 4 to 48 weeks with saffron or its extracts, both alone or in combination with conventional drugs. Saffron was more effective than placebo in improving cognition, depression with an overall effect size of -4.26 (95% CI: -5.76, -2.77), anxiety of -3.75 (95% CI: -5.83, -1.67), and sleep disorders of -1.91 (95% CI: -2.88, -0.93). Saffron was non-inferior to conventional drugs for treating cognitive disorders, depression, anxiety, ADHD, and OCD, and it exhibited good tolerance with few side effects. Saffron may exert protective roles for neurological and psychiatric disorders and represents a relatively favorable and safe treatment.

Effortful and effortless training of executive functions improve brain multiple demand system activities differently: an activation likelihood estimation meta-analysis of functional neuroimaging studies.

Both effortful and effortless training have been shown to be effective in enhancing individuals' executive functions. Effortful training improves domain-specific EFs, while effortless training improves domain-general EFs. Furthermore, effortful training has significantly higher training effects on EFs than effortless training. The neural mechanism underlying these different effects remained unclear. The present study conducted meta-analysis on neuroimaging studies to explore the changes of brain activations induced by effortful and effortless training. The results showed that effortful training induced greater activation in superior frontal gyrus, while effortless training induced greater activation in middle frontal gyrus, precuneus and cuneus. The brain regions of MD system enhanced by effortful training were more associated with core cognitive functions underlying EFs, while those enhanced by effortless training were more correlated with language functions. In addition, the significant clusters induced by effortful training had more overlaps with the MD system than effortless training. These results provided us with possibility to discuss the different behavioral results brought by effortful and effortless training.

Biomonitoring, exposure routes and risk assessment of chlorinated paraffins in humans: a mini-review.

Chlorinated paraffins (CPs), which were conventionally classified into short- (SCCPs), medium- (MCCPs) and long- (LCCPs) chain CPs, have received growing attention due to their wide usage and extensive detection in environmental samples and biota. The number of studies regarding the biomonitoring of CPs in human beings increased rapidly and their health risk gained great concern. This review summarized their occurrence and homologue patterns in human matrices including blood/serum, placenta, cord serum and breast milk. As the production and usage of SCCPs was progressively banned after being listed in Annex A of the Stockholm Convention, the production of MCCPs and LCCPs was stimulated. Accordingly, the ratio of MCCPs/SCCPs in human samples has increased rapidly in the last 5 years. The current understanding of exposure routes and risk assessments of CPs was also reviewed. Oral dietary intake is the most predominant source of daily CP intake, but dust ingestion, inhalation and dermal exposure is also nonnegligible, especially for MCCPs and LCCPs. Furthermore, the reported upper bound of the estimated daily intakes (EDIs) in various risk assessment studies was close to or exceeded the tolerable daily intakes (TDIs). Considering the bioaccumulation and long-lasting exposure of CPs, their health impacts on humans and the ecosystem required continuous monitoring and evaluation.

Effect of low-glycemic index diet advice on pregnant outcomes in women with elevated risk of gestational diabetes mellitus: A meta-analysis of randomized controlled trails.

BACKGROUND AND AIMS: The beneficial effect of low-glycemic index (GI) diet on gestational diabetes mellitus (GDM) has been suggested in many observational studies; however, results from intervention trials remain inconsistent. This study aims to estimate the effect of interventions with low-GI dietary advice on pregnant outcomes in women with elevated risk of GDM. DESIGN: PubMed, Web of Science, Embase, and Cochrane Library databases were searched for randomized clinical trials (RCTs) through March 2022. Studies reporting the effect of low-GI diet advice intervention on maternal and fetal outcomes in pregnant women with increased risks of GDM were included. Random or fixed effects model was used to calculate combined treatment effects. Publication bias was assessed via Begg's and Egger's tests and funnel plot inspection. RESULTS: Nine RCTs recruiting 3416 participants were included. Low-GI diet advice did not modulate the risk of GDM. Compared with control diets, low-GI diet advice significantly reduced gestational weight gain (GWG) (weighted mean differences, WMD = -0.93 kg, 95% CI: -1.31, -0.55; p < 0.001; n = 7) and the risk of premature birth (RR = 0.55, 95% CI: 0.35, 0.88; p = 0.012; n = 5). In subgroup analyses, the effect of low-GI diet interventions on premature birth was significant only in women with BMI higher than 30 kg/m2 (RR = 0.28, 95% CI: 0.10, 0.77, p = 0.014; n = 3); the significant effect on GWG was not altered by stratification of BMI and the type of GDM risk factors. No significant changes in other maternal and newborn outcomes were found. CONCLUSIONS: Low-GI diet advice interventions during pregnancy decreased GWG and the risk of premature birth in women with elevated GDM risk; however, the interventions did not significantly prevent GDM development in these women.

Size-tunable energy gaps of hydrogen-terminated biphenylene segments.

The electronic properties of hydrogen-terminated biphenylene (BP) segments of different sizes on the sub-nanoscale are explored using density functional theory, and the size dependence of the energy gap is evaluated using a structural parameter as a function of the bond lengths and the electronic density contributions. More importantly, the energy gap is observed to decrease linearly with the reduced hydrogen-to-carbon ratio of the corresponding structures, while the decrease-rate undergoes a diminution of four times at a gap of 0.5 eV due to the transformed distribution of the lowest unoccupied molecular orbital. The results give a deep insight into the size-tunable energy gaps of BPs and provide a possibility for the preparation of hydrogen-terminated carbon materials with a desirable energy gap.

Establishment and validation of a risk prediction model incorporating concentrations of linezolid and its metabolite PNU142300 for linezolid-induced thrombocytopenia.

BACKGROUND: Linezolid-induced thrombocytopenia is the main factor restricting the clinical application of linezolid. OBJECTIVES: To investigate the relationship between PNU-14230 concentration and linezolid-induced thrombocytopenia and further develop and validate a risk model for predicting linezolid-induced thrombocytopenia. METHODS: A regression model was constructed to predict the occurrence of linezolid-induced thrombocytopenia, and further externally validated. The predictive performance was evaluated by receiver operating characteristic curve and Hosmer-Lemeshow test. Linezolid Cmin and PNU-142300 concentrations were compared for different kidney function groups. The Kaplan-Meier method was used to estimate the difference in cumulative incidence of linezolid-induced thrombocytopenia among different kidney function patients. RESULTS: In the derivation (n = 221) and validation (n = 158) cohorts, 28.5% and 24.1% of critically ill patients developed linezolid-induced thrombocytopenia. Logistic regression analysis indicated that the independent risk factors were linezolid Cmin, PNU-142300 concentration, baseline platelet count, renal insufficiency (RI) and continuous venovenous haemofiltration (CVVH). The AUC for the risk model was 0.901, and the model was good (P = 0.633). The model also showed good discrimination (AUC 0.870) and calibration (P = 0.282) in the external validation cohort. Compared with normal kidney function patients, patients with RI and CVVH had higher linezolid Cmin and PNU-142300 concentrations (P < 0.001) and higher cumulative incidence of linezolid-induced thrombocytopenia (P < 0.001). CONCLUSIONS: PNU142300 concentration, as well as linezolid Cmin, might identify patients at risk of linezolid-induced thrombocytopenia. The risk prediction model had good predictive performance for linezolid-induced thrombocytopenia development. Concentrations of linezolid and PNU-142300 accumulated in patients with RI and CVVH.

Plasmon-Mediated Hydrogen Dissociation with Symmetry Tunability.

The atomic-scale mechanism of plasmon-mediated H2 dissociation on gold nanoclusters is investigated using time-dependent density functional theory. The position relationship between the nanocluster and H2 has a strong influence on the reaction rate. When the hydrogen molecule is located in the interstitial center of the plasmonic dimer, the hot spot here has a great field enhancement, which can promote dissociation effectively. The change in the molecular position results in symmetry breaking, and the molecular dissociation is inhibited. For the asymmetric structure, direct charge transfer from the gold cluster to the antibonding state of the hydrogen molecule by plasmon decay makes a prominent contribution to the reaction. The results provide deep insights into the influence of structural symmetry on plasmon-assisted photocatalysis in the quantum regime.

[Research Progress on the Role of Laminin Subunit Alpha 4 in Diseases].

Laminin subunit alpha 4 (LAMA4),a member of the laminin family,is present in the intercellular matrix of adult tissues as a major component of basement membrane.LAMA4 is involved in the adhesion of cells and can bind to corresponding integrins to activate relevant signaling pathways,playing an essential role in the growth,proliferation,and migration of cells.It has been demonstrated that LAMA4 is associated with the occurrence and development of a variety of diseases including tumors,and the expression of LAMA4 can be used as a biomarker of tumor diagnosis and prognosis.This paper summarizes the current research progress in LAMA4 with the focus on the relationship between LAMA4 and diseases,especially tumor,with a view to provide new directions for the future research.

The neural representations underlying asymmetric cross-modal prediction of words.

Cross-modal prediction serves a crucial adaptive role in the multisensory world, yet the neural mechanisms underlying this prediction are poorly understood. The present study addressed this important question by combining a novel audiovisual sequence memory task, functional magnetic resonance imaging (fMRI), and multivariate neural representational analyses. Our behavioral results revealed a reliable asymmetric cross-modal predictive effect, with a stronger prediction from visual to auditory (VA) modality than auditory to visual (AV) modality. Mirroring the behavioral pattern, we found the superior parietal lobe (SPL) showed higher pattern similarity for VA than AV pairs, and the strength of the predictive coding in the SPL was positively correlated with the behavioral predictive effect in the VA condition. Representational connectivity analyses further revealed that the SPL mediated the neural pathway from the visual to the auditory cortex in the VA condition but was not involved in the auditory to visual cortex pathway in the AV condition. Direct neural pathways within the unimodal regions were found for the visual-to-visual and auditory-to-auditory predictions. Together, these results provide novel insights into the neural mechanisms underlying cross-modal sequence prediction.

Factors affecting cataract among the elderly population / 预防医学

Objective@#To investigate the factors affecting cataract among the elderly, so as to provide insights into cataract control.@*Methods@#Based on the major public health monitoring project of Zhejiang Province, residents at ages of 60 years and older were selected from 7 districts (counties) using a multi-stage stratified cluster random sampling method, and were followed up every other year from 2014 to 2020. Demographics, lifestyle, dietary habits and cataract incidence were collected, and factors affecting the incidence of cataract were identified using a multivariable Cox proportional hazard regression model.@*Results@# Totally 9 642 residents were investigated, with a mean age of (68.89±7.39) years, and including 4 635 males (48.07%). There were 828 incident cataract cases, with an incidence rate of 20.946/1 000 person-years. Multivariable Cox proportional hazard regression analysis showed that women (HR=1.695, 95%CI: 1.377-2.088), age of 65 years and older (HR=1.707-5.044, 95%CI: 1.400-7.327), overweight/obesity (HR=1.313, 95%CI: 1.131-1.524), educational level (primary school, HR=1.642, 95%CI: 1.400, 1.926; junior high school, HR=1.553, 95%CI: 1.148-2.102), annual family income (10 000 to 50 000 Yuan, HR=1.353, 95%CI: 1.155-1.585; 50 000 to 100 000 Yuan, HR=0.663, 95%CI: 0.500-0.881; 100 000 to 150 000 Yuan, HR=0.340, 95%CI: 0.204-0.565), smoking (HR=0.649, 95%CI: 0.494-0.853), frequency of vegetable intake of >3 days/week (HR=0.693, 95%CI: 0.527-0.912), frequency of fruit intake of >3 days/ week (HR=0.833, 95%CI: 0.694-0.899), frequency of egg intake of >3 days/week (HR=0.579, 95%CI: 0.450-0.745), frequency of soy products intake of >3 days/week (HR=0.706, 95%CI: 0.588-0.849), frequency of dairy products intake of >3 days/week (HR=1.510, 95%CI: 1.199-1.901) and frequency of nut intake of >3 days/week (HR=1.733, 95%CI: 1.162-2.586) were statistically associated with the development of cataract among the elderly. @*Conclusion @#Gender, age, body mass index, educational level, income, smoking, and frequency of vegetables, fruits, eggs, soy products, dairy products and nuts intake are associated with the development of cataracts.

What Makes Urban Communities More Resilient to COVID-19? A Systematic Review of Current Evidence.

It has been more than two years since the outbreak of the COVID-19 epidemic at the end of 2019. Many scholars have introduced the "resilience" concept into COVID-19 prevention and control to make up for the deficiencies in traditional community governance. This study analyzed the progress in research on social resilience, which is an important component of community resilience, focusing on the current literature on the impact of social resilience on COVID-19, and proposed a generalized dimension to integrated previous relevant literature. Then, VOSviewer was used to visualize and analyze the current progress of research on social resilience. The PRISMA method was used to collate studies on social resilience to the pandemic. The result showed that many current policies are effective in controlling COVID-19, but some key factors, such as vulnerable groups, social assistance, and socioeconomics, affect proper social functioning. Some scholars have proposed effective solutions to improve social resilience, such as establishing an assessment framework, identifying priority inoculation groups, and improving access to technology and cultural communication. Social resilience to COVID-19 can be enhanced by both external interventions and internal regulation. Social resilience requires these two aspects to be coordinated to strengthen community and urban pandemic resilience.

Detecting Asymptomatic Infections of Rice Bacterial Leaf Blight Using Hyperspectral Imaging and 3-Dimensional Convolutional Neural Network With Spectral Dilated Convolution.

Rice is one of the most important food crops for human beings. Its total production ranks third in the grain crop output. Bacterial Leaf Blight (BLB), as one of the three major diseases of rice, occurs every year, posing a huge threat to rice production and safety. There is an asymptomatic period between the infection and the onset periods, and BLB will spread rapidly and widely under suitable conditions. Therefore, accurate detection of early asymptomatic BLB is very necessary. The purpose of this study was to test the feasibility of detecting early asymptomatic infection of the rice BLB disease based on hyperspectral imaging and Spectral Dilated Convolution 3-Dimensional Convolutional Neural Network (SDC-3DCNN). First, hyperspectral images were obtained from rice leaves infected with the BLB disease at the tillering stage. The spectrum was smoothed by the Savitzky-Golay (SG) method, and the wavelength between 450 and 950 nm was intercepted for analysis. Then Principal Component Analysis (PCA) and Random Forest (RF) were used to extract the feature information from the original spectra as inputs. The overall performance of the SDC-3DCNN model with different numbers of input features and different spectral dilated ratios was evaluated. Lastly, the saliency map visualization was used to explain the sensitivity of individual wavelengths. The results showed that the performance of the SDC-3DCNN model reached an accuracy of 95.4427% when the number of inputs is 50 characteristic wavelengths (extracted by RF) and the dilated ratio is set at 5. The saliency-sensitive wavelengths were identified in the range from 530 to 570 nm, which overlaps with the important wavelengths extracted by RF. According to our findings, combining hyperspectral imaging and deep learning can be a reliable approach for identifying early asymptomatic infection of the rice BLB disease, providing sufficient support for early warning and rice disease prevention.

AQP9 (Aquaporin 9) Determines Arsenic Uptake and Tolerance in Human Hepatocellular Carcinoma Cells In Vitro.

Arsenic-based therapeutic strategies, even though promising for acute promyelocytic leukemia (APL), are limited by arsenic-related toxic effect and resistance with unknown mechanisms. The purpose of this study is to better understand the different sensitivities of hepatocellular carcinoma cells to arsenic and its mechanism. Arsenic-sensitive liver cancer cell line (HepG2) and arsenic-resistant HepG2 (AsHepG2) cells are employed to study the role of aquaporin 9 (AQP9) in arsenic uptake and tolerance. The half-maximal inhibitory concentration (IC50) value of arsenic in AsHepG2 cells (15.59 ± 1.36 µM) is significantly higher than that in HepG2 cells (7.33 ± 0.93 µM; p= 0.0288). We demonstrated that, with the treatment of sodium arsenite (NaAsO2), arsenic was accumulated at a significantly lower level in AsHepG2 cells in comparison with HepG2 cells (p= 0.00549). Further, arsenic level in AsHepG2 cells reaches a plateau after six hours of treatment, whereas arsenic continues to increase in HepG2 cells during the entire experimental period. Mechanistic study showed that the expression of AQP9 is decreased in a dose-dependent manner in AsHepG2 cells, but no significant difference in HepG2 cells. Furthermore, NaAsO2 dramatically increases AQP9 and p38 phosphorylation, which may partially regulate arsenic sensitivity in both cell lines. In conclusion, the expression and phosphorylation of AQP9 regulated by p38 kinase are involved in the arsenic uptake, thus regulating cellular arsenic sensitivity.

Continuous infusion versus intermittent infusion of vancomycin in critically ill patients undergoing continuous venovenous hemofiltration: a prospective interventional study.

BACKGROUND: A prospective interventional study comparing outcomes in critically ill patients receiving intermittent infusion (II) or continuous infusion (CI) of vancomycin during continuous venovenous hemofiltration (CVVH) is lacking. The objective of this study was to compare the pharmacokinetic/pharmacodynamics (PK/PD) target attainment, therapeutic efficacy and safety among critically ill patients who received CI or II of vancomycin in a prospective interventional trial and to explore the correlations of effluent flow rate (EFR) with PK/PD indices. METHODS: This prospective interventional study was conducted in two independent intensive care units (ICUs) from February 2021 to January 2022. Patients in one ICU were assigned to receive CI (intervention group) of vancomycin, whereas patients in the other ICU were assigned to receive II regimen (control group). The primary outcome was to compare the PK/PD target attainment, including target concentration and target area under the curve over 24 h to minimum inhibitory concentration (AUC24/MIC). RESULTS: Overall target attainment of PK/PD indices was higher with CI compared with II, irrespective of target concentration (78.7% vs. 40.5%; P < 0.05) or AUC24/MIC (53.2% vs. 28.6%; P < 0.05). There were no significant differences in clinical success (72.2% vs. 50.0%; P = 0.183) and microbiological success (83.3% vs. 75.0%, P = 0.681) between the patients treated with CI or II of vancomycin. Adverse reactions occurred at similar rates (0.0% vs. 4.4%; P = 0.462), and mortality between the two modalities was also not significant different (21.7% vs. 17.9%; P = 0.728). Correlation analysis showed a weak to moderately inverse correlation of EFR with observed concentration (r = - 0.3921, P = 0.01) and AUC24/MIC (r = - 0.3811, P = 0.013) in the II group, whereas the correlation between EFR and observed concentration (r = - 0.5711, P < 0.001) or AUC24/MIC (r = - 0.5458, P < 0.001) in the CI group was stronger. CONCLUSION: As compared to II, CI of vancomycin in critically ill patients undergoing CVVH was associated with improved attainment of PK/PD indices. Furthermore, the inverse correlation of PK/PD indices with EFR was stronger among patients treated with CI of vancomycin. Trial registration The trial was registered in the Chinese clinical trial registration center (21/01/2021-No. ChiCTR2100042393).

Applying spectral fractal dimension index to predict the SPAD value of rice leaves under bacterial blight disease stress.

BACKGROUND: The chlorophyll content is a vital indicator for reflecting the photosynthesis ability of plants and it plays a significant role in monitoring the general health of plants. Since the chlorophyll content and the soil-plant analysis development (SPAD) value are positively correlated, it is feasible to predict the SPAD value by calculating the vegetation indices (VIs) through hyperspectral images, thereby evaluating the severity of plant diseases. However, current indices simply adopt few wavelengths of the hyperspectral information, which may decrease the prediction accuracy. Besides, few researches explored the applicability of VIs over rice under the bacterial blight disease stress. METHODS: In this study, the SPAD value was predicted by calculating the spectral fractal dimension index (SFDI) from a hyperspectral curve (420 to 950 nm). The correlation between the SPAD value and hyperspectral information was further analyzed for determining the sensitive bands that correspond to different disease levels. In addition, a SPAD prediction model was built upon the combination of selected indices and four machine learning methods. RESULTS: The results suggested that the SPAD value of rice leaves under different disease levels are sensitive to different wavelengths. Compared with current VIs, a stronger positive correlation was detected between the SPAD value and the SFDI, reaching an average correlation coefficient of 0.8263. For the prediction model, the one built with support vector regression and SFDI achieved the best performance, reaching R2, RMSE, and RE at 0.8752, 3.7715, and 7.8614%, respectively. CONCLUSIONS: This work provides an in-depth insight for accurately and robustly predicting the SPAD value of rice leaves under the bacterial blight disease stress, and the SFDI is of great significance for monitoring the chlorophyll content in large-scale fields non-destructively.

Optical properties and energy transfer performances in high quality Cr,Nd: YAG transparent laser ceramics for solar pumped lasers.

Realizing a high solar light conversion magnitude in Cr,Nd: YAG transparent ceramic is crucial to its applications in solar pumped solid state lasers. In this study, high quality Cr,Nd:YAG transparent laser ceramics with homogeneous microstructure and theoretical transmittance were fabricated, and an efficient laser oscillation of watt-level was realized by pumping ceramic at 808 nm. There were no any characteristic absorptions corresponding to Cr2+ or Cr4+ ions detected, even when the Cr3+ ion doping concentration reached 0.6 at.%. Increasing Cr3+ and Nd3+ doping concentrations significantly enhanced the emission intensity of ceramics at 1.06 µm, and energy transfer efficiency of the 0.3 at.% Cr,Nd: YAG ceramics was increased from 14.9% to 36.9% when increasing Nd3+ ion concentration from 0.3 at.% to 1.0 at.%, with an increasing magnitude of 247.6%. The results indicated that Cr,Nd: YAG transparent ceramic is a promising gain medium for solar pumped solid state lasers.