Inverse design of metasurfaces with customized transmission characteristics of frequency band based on generative adversarial networks.

In recent years, deep learning (DL) has demonstrated significant potential in the inverse design of metasurfaces, and the generation of metasurfaces with customized transmission characteristics of frequency band remains a challenging and underexplored area. In this study, we propose a DL-assisted method for the inverse design of transmissive metasurfaces. The method consists of a generative adversarial network (GAN)-based graph generator, an electromagnetic response predictor, and a genetic algorithm optimizer. By integrating these components, we can obtain customized metasurfaces with desired transmission characteristics of frequency band. We demonstrate the effectiveness of the proposed method through examples of inverse-designed three-layer cascaded transmissive metasurfaces with wideband, dual-band, and stopband responses in the 8∼12 GHz frequency range. Specifically, we realize three different types of dual-band metasurfaces, namely double-wide, front-wide and rear-narrow, and front-narrow and rear-wide configurations. Additionally, we analyze the accuracy and reliability of the inverse design method by employing data from the training dataset, self-defined objectives, and bandwidth-reduced target responses scaled from the wideband type as design inputs. Quantitative evaluation is performed using metrics such as mean absolute error and average precision. The proposed method successfully achieves the desired effect as intended.

Structure of a TOC-TIC supercomplex spanning two chloroplast envelope membranes.

The TOC and TIC complexes are essential translocons that facilitate the import of the nuclear genome-encoded preproteins across the two envelope membranes of chloroplast, but their exact molecular identities and assembly remain unclear. Here, we report a cryoelectron microscopy structure of TOC-TIC supercomplex from Chlamydomonas, containing a total of 14 identified components. The preprotein-conducting pore of TOC is a hybrid ß-barrel co-assembled by Toc120 and Toc75, while the potential translocation path of TIC is formed by transmembrane helices from Tic20 and YlmG, rather than a classic model of Tic110. A rigid intermembrane space (IMS) scaffold bridges two chloroplast membranes, and a large hydrophilic cleft on the IMS scaffold connects TOC and TIC, forming a pathway for preprotein translocation. Our study provides structural insights into the TOC-TIC supercomplex composition, assembly, and preprotein translocation mechanism, and lays a foundation to interpret the evolutionary conservation and diversity of this fundamental translocon machinery.

A Novel Scale for Assessment of Stroke Severity at Symptom Onset: Correlation With Neurological Deterioration and Outcome.

Objective: To propose a novel scale for the assessment of stroke severity at symptom onset and to investigate whether it is associated with ultra-early neurological deterioration (UND) and functional outcomes. Methods: The Chongqing Stroke Scale (CQSS) was constructed based on key aspects of history, emphasizing language, motor function, and level of consciousness to yield a total 0-11 scale. The diagnostic performance of the CQSS was assessed in 215 ischemic stroke patients between June 2017 and October 2017 in a tertiary hospital. Patients were included if they presented within 24 h after onset of symptoms and they or their witness can recall the scenario at symptom onset. UND was defined as an increase ≥2 points on the CQSS between symptom onset and admission. Functional outcomes were assessed using the 3-month modified Rankin scale. The correlation between the CQSS score and baseline National Institutes of Health Stroke Scale (NIHSS) score was assessed. The sensitivity, specificity, and positive and negative predictive values of CQSS for the outcomes were calculated. Logistic regression was used to test the association between the CQSS score and functional outcomes. Results: A total of 215 patients with available CQSS scores were included. Baseline CQSS scores at symptom onset were correlated with the admission NIHSS score (r = 0.56, p < 0.001) and functional outcome at 3 months (r = 0.47, p < 0.001). Baseline CQSS ≥ 6 was an independent predictor of functional outcome at 3 months (odds ratio, 12.61; 95% confidence interval 5.68-27.97, p < 0.001). UND was observed in 20 (9.30%) patients. The 90-day mortality was significantly higher in patients with UND than those without UND (25.0 vs. 8.2%, p < 0.001). After adjusting for age, admission systolic blood pressure, hypertension, and diabetes, UND independently predicted poor functional outcome in the multivariate logistic regression model (odds ratio, 9.69; 95% confidence interval 3.19-29.45, p < 0.001). Conclusions: The newly developed CQSS is a simple and easy-to-perform scale that allows a quantitative evaluation of the stroke severity at symptom onset and an assessment of UND before hospital admission. It is associated with NIHSS and predicts functional outcome in patients with acute ischemic stroke.

Association between Extracranial Carotid Artery Tortuosity and Clinical Outcomes in Anterior Circulation Acute Ischemic Stroke without Undergoing Endovascular Treatment.

BACKGROUND: Extracranial carotid artery (ECA) tortuosity may influences successful recanalization rates of mechanical thrombectomy in acute ischemic stroke (AIS), yet the relationship between ECA tortuosity and the prognosis of patients with anterior circulation AIS who cannot undergo endovascular treatment remains uncertain. We hypothesized that increased tortuosity of the ECA leads to unfavorable outcomes in such patients. METHODS: Patients with anterior circulation AIS who underwent computed tomography angiography of the head and neck in our hospital between March 2018 and November 2018 were retrospectively analyzed. The tortuosity of the bilateral ECA was measured, and functional outcomes were evaluated by a modified Rankin Scale (mRS) at 90 days. Multivariate logistic regression models were used to determine the association between ECA tortuosity and outcomes of patients. RESULTS: A total of 203 patients were enrolled in our study, including 140 patients (68.97%) with favorable outcomes (mRS, 0-2) and 63 patients (31.03%) with unfavorable outcomes (mRS, 3-6). After adjusting for age, atrial fibrillation, stroke territory, and posthospital antithrombotics/statins therapy in multivariate logistic regression model I, ECA tortuosity (odds ratio, 1.052; 95% confidence interval, 1.010-1.096; P = .015) was an independent risk of unfavorable outcomes in enrolled patients. In the other 2 models (II and III) which adjusted for age, sex, baseline National Institutes of Health Stroke Scale score, and with or without posthospital medication, ECA tortuosity was also showed independent relationship to unfavorable outcomes. The optimal cutoff was 12.5 to predict the unfavorable outcomes in a receiver operating characteristic curve. CONCLUSIONS: Our study demonstrated that the ECA tortuosity is an independent predictor of unfavorable outcomes for anterior circulation AIS patients who without undergoing endovascular treatment after hospital admission. ECA tortuosity values greater than 12.5 may indicate an unfavorable outcome.

Objective diagnosis of post-stroke depression using NMR-based plasma metabonomics.

Background: Post-stroke depression (PSD) is a frequent and serious complication of stroke. However, the underlying molecular basis of PSD remains largely unknown, and no empirical laboratory tests were available to diagnose this disorder. Materials and methods: A proton nuclear magnetic resonance (1H NMR)-based metabonomic approach was employed to profile plasma samples from 32 PSD, 35 stroke patients and 35 healthy comparison subjects (the training set) in order to identify metabolite biomarkers for PSD. Then, 10 PSD, 11 stroke patients and 11 healthy comparison subjects (test set) were used to validate the diagnostic performance of these biomarkers. Results: The multivariate statistical analysis demonstrated that PSD group was significantly distinguishable from non-PSD groups (non-depression stroke patients and healthy comparison group). Five plasma metabolites (phenylalanine, tyrosine, 1-methylhistidine, 3-methylhistidine and LDL CH3-(CH2)n-) were identified responsible for distinguishing PSD from non-PSD subjects. These metabolites were mainly involved in neurotransmitter metabolism and oxidative stress. The biomarker panel composing of these metabolites was capable of distinguishing test samples with a sensitivity of 100.0% and a specificity of 95.5%. Conclusion: Our findings suggest that plasma disturbances of neurotransmitter levels and oxidative stress were implicated in the onset of PSD; these disturbed metabolites biomarkers facilitate to the development of diagnostic tool for PSD.

Expansion-Prone Hematoma: Defining a Population at High Risk of Hematoma Growth and Poor Outcome.

BACKGROUND: Noncontrast computed tomography (CT) markers are increasingly used for predicting hematoma expansion. The aim of our study was to investigate the predictive value of expansion-prone hematoma in predicting hematoma expansion and outcome in patients with intracerebral hemorrhage (ICH). METHODS: Between July 2011 and January 2017, ICH patients who underwent baseline CT scan within 6 h of symptoms onset and follow-up CT scan were recruited into the study. Expansion-prone hematoma was defined as the presence of one or more of the following imaging markers: blend sign, black hole sign, or island sign. The diagnostic performance of blend sign, black hole sign, island sign, and expansion-prone hematoma in predicting hematoma expansion was assessed. Predictors of hematoma growth and poor outcome were analyzed using multivariable logistical regression analysis. RESULTS: A total of 282 patients were included in our final analysis. Of 88 patients with early hematoma growth, 69 (78.4%) had expansion-prone hematoma. Expansion-prone hematoma had a higher sensitivity and accuracy for predicting hematoma expansion and poor outcome when compared with any single imaging marker. After adjustment for potential confounders, expansion-prone hematoma independently predicted hematoma expansion (OR 28.33; 95% CI 12.95-61.98) and poor outcome (OR 5.67; 95% CI 2.82-11.40) in multivariable logistic model. CONCLUSION: Expansion-prone hematoma seems to be a better predictor than any single noncontrast CT marker for predicting hematoma expansion and poor outcome. Considering the high risk of hematoma expansion in these patients, expansion-prone hematoma may be a potential therapeutic target for anti-expansion treatment in future clinical studies.

Diagnosing chronic inflammatory demyelinating polyradiculoneuropathy with triple stimulation technique.

OBJECTIVE: To assess the value of triple stimulation technique (TST) for diagnose of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). METHODS: Seven clinically suspected CIDP patients who did not fulfill EFNS/PNS electrodiagnostic criteria for demyelinating neuropathy were enrolled in our study. Routine nerve conduction studies, lumbar puncture, spinal cord magnetic resonance imaging and TST were detected. The patients were being treated with oral prednisone starting at 1 mg/kg daily. The overall disability sum score was performed to evaluate the effect of corticosteroids. RESULTS: Twenty-eight motor nerves were tested with TST, two conduction blocks (CBs) were detected between the root emergence and the Erb point in six patients respectively and one CB was detected in one patient. Symptoms of all seven patients improved after treatment with oral prednisone. CONCLUSION: TST can detect CBs located between the root emergence and the Erb point. TST is useful for early diagnosis of CIDP.

Cationic Organochalcogen with Monomer/Excimer Emissions for Dual-Color Live Cell Imaging and Cell Damage Diagnosis.

Studies on the development of fluorescent organic molecules with different emission colors for imaging of organelles and their biomedical application are gaining lots of focus recently. Here, we report two cationic organochalcogens 1 and 2, both of which exhibit very weak green emission (Φ1 = 0.12%; Φ2 = 0.09%) in dilute solution as monomers, but remarkably enhanced green emission upon interaction with nucleic acids and large red-shifted emission in aggregate state by the formation of excimers at high concentration. More interestingly, the monomer emission and excimer-like emission can be used for dual color imaging of different organelles. Upon passively diffusing into cells, both probes selectively stain nucleoli with strong green emission upon 488 nm excitation, whereas upon 405 nm excitation, a completely different stain pattern by staining lysosomes (for 1) or mitochondria (for 2) with distinct red emission is observed because of the highly concentrated accumulation in these organelles. Studies on the mechanism of the accumulation in lysosomes (for 1) or mitochondria (for 2) found that the accumulations of the probes are dependent on the membrane permeabilization, which make the probes have great potential in diagnosing cell damage by sensing lysosomal or mitochondrial membrane permeabilization. The study is demonstrative, for the first time, of two cationic molecules for dual-color imaging nucleoli and lysosomes (1)/mitochondria (2) simultaneously in live cell based on monomer and excimer-like emission, respectively, and more importantly, for diagnosing cell damage.

Evolutionary and expression analyses of soybean basic Leucine zipper transcription factor family.

BACKGROUND: Soybean, a major legume crop native to East Asia, presents a wealth of resources for utilization. The basic leucine zipper (bZIP) transcription factors play important roles in various biological processes including developmental regulation and responses to environmental stress stimuli. Currently, little information is available regarding the bZIP family in the legume crop soybean. RESULTS: Using a genome-wide domain analysis, we identified 160 GmbZIP genes in soybean genome, named from GmbZIP1 to GmbZIP160. These 160GmbZIP genes, distributed unevenly across 20 chromosomes, were grouped into 12 subfamilies based on phylogenetic analysis. Gene structure and conserved motif analyses showed that GmbZIP within the same subfamily shared similar intron-exon organizations and motif composition. Syntenic and phylogenetic analyses identified 40 Arabidopsis bZIP genes and 83 soybean bZIP genes as orthologs. By investigating the expression profiling of GmbZIP in different tissues and under drought and flooding stresses, we showed that a majority of GmbZIP (83.44%) exhibited transcript abundance in all examined tissues and 75.6% displayed transcript changes after drought and flooding treatment, suggesting that GmbZIP may play a broad role in soybean development and response to water stress. CONCLUSIONS: One hundred sixty GmbZIP genes were identified in soybean genome. Our results provide insights for the evolutionary history of bZIP family in soybean and shed light on future studies on the function of bZIP genes in response to water stress in soybean.

Black Hole Sign Predicts Poor Outcome in Patients with Intracerebral Hemorrhage.

BACKGROUND: In spontaneous intracerebral hemorrhage (ICH), black hole sign has been proposed as a promising imaging marker that predicts hematoma expansion in patients with ICH. The aim of our study was to investigate whether admission CT black hole sign predicts hematoma growth in patients with ICH. METHODS: From July 2011 till February 2016, patients with spontaneous ICH who underwent baseline CT scan within 6 h of symptoms onset and follow-up CT scan were recruited into the study. The presence of black hole sign on admission non-enhanced CT was independently assessed by 2 readers. The functional outcome was assessed using the modified Rankin Scale (mRS) at 90 days. Univariate and multivariable logistic regression analyses were performed to assess the association between the presence of the black hole sign and functional outcome. RESULTS: A total of 225 patients (67.6% male, mean age 60.3 years) were included in our study. Black hole sign was identified in 32 of 225 (14.2%) patients on admission CT scan. The multivariate logistic regression analysis demonstrated that age, intraventricular hemorrhage, baseline ICH volume, admission Glasgow Coma Scale score, and presence of black hole sign on baseline CT independently predict poor functional outcome at 90 days. There are significantly more patients with a poor functional outcome (defined as mRS ≥4) among patients with black hole sign than those without (84.4 vs. 32.1%, p < 0.001; OR 8.19, p = 0.001). CONCLUSIONS: The CT black hole sign independently predicts poor outcome in patients with ICH. Early identification of black hole sign is useful in prognostic stratification and may serve as a potential therapeutic target for anti-expansion clinical trials.

Comparison of Swirl Sign and Black Hole Sign in Predicting Early Hematoma Growth in Patients with Spontaneous Intracerebral Hemorrhage.

BACKGROUND Early hematoma growth is associated with poor outcome in patients with spontaneous intracerebral hemorrhage (ICH). The swirl sign (SS) and the black hole sign (BHS) are imaging markers in ICH patients. The aim of this study was to compare the predictive value of these 2 signs for early hematoma growth. MATERIAL AND METHODS ICH patients were screened for the appearance of the 2 signs within 6 h after onset of symptoms. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the 2 signs in predicting early hematoma growth were assessed. The accuracy of the 2 signs in predicting early hematoma growth was analyzed by receiver-operator analysis. RESULTS A total of 200 patients were enrolled in this study. BHS was found in 30 (15%) patients, and SS was found in 70 (35%) patients. Of the 71 patients with early hematoma growth, BHS was found on initial computed tomography scans in 24 (33.8%) and SS in 33 (46.5%). The sensitivity, specificity, PPV, and NPV of BHS for predicting early hematoma growth were 33.8%, 95.3%, 80.0%, and 72.0%, respectively. The sensitivity, specificity, PPV, and NPV of SS were 46.5%, 71.3%, 47.0%, and 71.0%, respectively. The area under the curve was 0.646 for BHS and 0.589 for SS (P=0.08). Multivariate logistic regression showed that presence of BHS is an independent predictor of early hematoma growth. CONCLUSIONS The Black hole sign seems to be good predictor for hematoma growth. The presence of swirl sign on admission CT does not independently predict hematoma growth in patients with ICH.

Complementary and alternative therapies for restless legs syndrome: An evidence-based systematic review.

Restless legs syndrome (RLS) is defined as an irresistible urge to move the legs, which is usually accompanied by paresthesias or dysesthesias at least twice weekly, and affects 2%-4% of adults in Europe and North America. This systematic review assesses the current complementary and alternative options for RLS and the potential benefits of those treatments on sleep quality, mood disorder, and quality of life. A systematic search of the PubMed, Embase, Cochrane, and Web of Science databases was conducted. Eighteen studies met the inclusion criterion, which included the use of the international RLS study group criteria. Complementary and alternative therapies have been found to be effective in both primary and secondary RLS. The severity of primary RLS symptoms can be significantly ameliorated by exercise training, transcutaneous spinal direct current stimulation, pneumatic compression devices, light therapy, repetitive transcranial magnetic stimulation, and acupuncture. Pneumatic compression devices and yoga also improve RLS-related disorders. Exercise training is highly efficacious in the reduction of symptom severity in uremic RLS and related effects such as poor quality of life. Endovenous laser ablation may be a good choice for patients with concurrent RLS and superficial venous insufficiency.

Decreased serum proNGF concentration in patients with Parkinson's disease.

Parkinson's disease (PD), a progressive and age-related neurodegenerative condition, is a common neurodegenerative disorder. However, no validated biomarkers for PD have been identified to date. Accumulating evidence supports the role of proNGF-p75NTR-sortilin signaling in the neurodegeneration and pathogenesis of PD. The aim of our study was to investigate alterations in serum proNGF concentrations in PD patients and related anxiety. Seventy-seven consecutive PD patients and 39 healthy controls were enrolled, and clinical data were collected. Modified Hoehn-Yahr Staging Scale, Unified Parkinson's Disease Rating Scale (UPDRS), and Hamilton Anxiety (HAMA) Scale scores were assessed upon admission. Serum proNGF concentration was compared between that of PD patients and healthy controls. Pearson correlation coefficients were determined to explore the relationship between proNGF concentration and UPDRS, Hoehn-Yahr, and HAMA scores. Received operating characteristic (ROC) curves and proNGF optimal cutoff point were used to distinguish PD and related anxiety. The median concentration of proNGF was significantly lower (p = 0.000) in PD patients (94.91 ng/L, range 85.92-118.06 ng/L) compared with that of healthy controls (106.67 ng/L, range 102.39-122.06 ng/L). The optimal proNGF cutoff point for distinguishing PD patients was 102.29 ng/L, and the sensitivity and specificity values were 87.0 and 100%, respectively. proNGF concentration positively correlated with UPDRS (r = 0.281, p = 0.013), Hoehn-Yahr (r = 0.260, p = 0.023), and HAMA (r = 0.276, p = 0.015) scores. Our results indicate that serum proNGF concentration may represent a biomarker for PD and its role in the pathogenesis of PD thus warrants further investigation.

Island Sign: An Imaging Predictor for Early Hematoma Expansion and Poor Outcome in Patients With Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: The aim of the study was to investigate the usefulness of the computed tomography (CT) island sign for predicting early hematoma growth and poor functional outcome. METHODS: We included patients with spontaneous intracerebral hemorrhage (ICH) who had undergone baseline CT within 6 hours after ICH symptom onset in our hospital between July 2011 and September 2016. Two readers independently assessed the presence of the island sign on the admission noncontrast CT scan. Multivariable logistic regression analysis was used to analyze the association between the presence of the island sign on noncontrast admission CT and early hematoma growth and functional outcome. RESULTS: A total of 252 patients who met the inclusion criteria were analyzed. Among them, 41 (16.3%) patients had the island sign on baseline noncontrast CT scans. In addition, the island sign was observed in 38 of 85 patients (44.7%) with hematoma growth. Multivariate logistic regression analysis demonstrated that the time to baseline CT scan, initial hematoma volume, and the presence of the island sign on baseline CT scan independently predicted early hematoma growth. The sensitivity of the island sign for predicting hematoma expansion was 44.7%, specificity 98.2%, positive predictive value 92.7%, and negative predictive value 77.7%. After adjusting for the patients' age, baseline Glasgow Coma Scale score, presence of intraventricular hemorrhage, presence of subarachnoid hemorrhage, admission systolic blood pressure, baseline ICH volume, and infratentorial location, the presence of the island sign (odds ratio, 3.51; 95% confidence interval, 1.26-9.81; P=0.017) remained an independent predictor of poor outcome in patients with ICH. CONCLUSIONS: The island sign is a reliable CT imaging marker that independently predicts hematoma expansion and poor outcome in patients with ICH. The noncontrast CT island sign may serve as a potential marker for therapeutic intervention.

Blend sign predicts poor outcome in patients with intracerebral hemorrhage.

INTRODUCTION: Blend sign has been recently described as a novel imaging marker that predicts hematoma expansion. The purpose of our study was to investigate the prognostic value of CT blend sign in patients with ICH. OBJECTIVES AND METHODS: Patients with intracerebral hemorrhage who underwent baseline CT scan within 6 hours were included. The presence of blend sign on admission nonenhanced CT was independently assessed by two readers. The functional outcome was assessed by using the modified Rankin Scale (mRS) at 90 days. RESULTS: Blend sign was identified in 40 of 238 (16.8%) patients on admission CT scan. The proportion of patients with a poor functional outcome was significantly higher in patients with blend sign than those without blend sign (75.0% versus 47.5%, P = 0.001). The multivariate logistic regression analysis demonstrated that age, intraventricular hemorrhage, admission GCS score, baseline hematoma volume and presence of blend sign on baseline CT independently predict poor functional outcome at 90 days. The CT blend sign independently predicts poor outcome in patients with ICH (odds ratio 3.61, 95% confidence interval [1.47-8.89];p = 0.005). CONCLUSIONS: Early identification of blend sign is useful in prognostic stratification and may serve as a potential therapeutic target for prospective interventional studies.

Early Hematoma Enlargement in Primary Intracerebral Hemorrhage.

BACKGROUND: Early hematoma growth is not uncommon in patients with intracerebral hemorrhage. It is a devastating complication that independently predicts poor outcome. The early hematoma enlargement is usually defined as an absolute increase in hematoma volume of greater than 33% on repeat CT scan. To date, no ideal animal model can mimic the exact pathophysiological process of early hematoma growth. OBJECTIVE: This review of early hematoma enlargement in primary intracerebral hemorrhage discusses definitions, pathophysiology, risk factors, and novel treatment options aimed at improving outcomes. CONCLUSION: Novel imaging predictors such as CT angiography spot sign and CT blend sign may predict early hematoma growth in patients with intracerebral hemorrhage. Monitoring and modulation of blood pressure may improve outcomes. Rapid reduction of blood pressure to <140 mm Hg may be safe in patients with intracerebral hemorrhage.

Association between processed meat and red meat consumption and risk for glioma: a meta-analysis from 14 articles.

OBJECTIVE: Epidemiologic studies evaluating the association between processed meat and red meat consumption and glioma risk have produced inconsistent results. Thus, the aim of this study was to conduct a meta-analysis to test the hypothesis that high levels of processed meat consumption could increase the risk for glioma. METHODS: Pertinent studies were identified by a search of PubMed and Web of Knowledge up to February 2014. Random-effects model was used to combine the results. Publication bias was estimated using Egger's regression asymmetry test. RESULTS: Fourteen studies involving 3641 cases about processed meat consumption and 3 studies involving 1156 cases about red meat consumption with risk for glioma were included in this meta-analysis. The combined relative risk (RR) of glioma associated with processed meat consumption was 1.25 (95% confidence interval [CI], 1.08-1.45) overall, and 1.28 (95% CI, 1.09-1.50) in the United States. For subgroup of study design, significant association was also found in case-control studies (RR, 1.33; 95% CI, 1.09-1.62), but not in the cohort studies. The association was not significant between red meat consumption and glioma risk (summary RR, 0.89; 95% CI, 0.71-1.12). No publication biases were found. CONCLUSIONS: Our analysis indicated that high levels of processed meat consumption might increase the risk for glioma, and findings are consistent with the hypothesis. No association was found between red meat consumption and glioma risk.

Theoretical investigation of a "turn-on" fluorescent sensor induced by complexation of mercury(II) ion.

A selective Hg²âº/Cu²âº-induced OFF-ON-OFF type of signaling pattern was calculated by density functional theory and time-dependent density functional theory method. Geometries, molecular orbitals, and interaction thermal energies were evaluated at the restricted hybrid Becke's three-parameter exchange functional using 6-31+G(d) basis set and relativistic effective core potentials. The optimized geometric structures are used to perform natural bond orbital (NBO) analysis. The main type of driving force is the electrostatic interactions between the metal ions and the electron-donating oxygen and nitrogen atoms. Maximum absorption spectrums of the complexes are mainly contributed by the HOMO → LOMO transition. The high selectivity of ligand H2NB for Hg²âº results in a "turn-on" fluorescent phenomenon.