Cascading Detection of Hydrogen Sulfide and N-Acetyltransferase 2 in Hepatocellular Carcinoma Cells Using a Two-Photon Fluorescent Probe.

Hydrogen sulfide (H2S), a critical gas signaling molecule, and N-acetyltransferase 2 (NAT2), a key enzyme in drug metabolism, are both known active biomarkers for liver function. However, the interactions and effects of H2S and NAT2 in living cells or lesion sites remain unknown due to the lack of imaging tools to achieve simultaneous detection of these two substances, making it challenging to implement real-time imaging and precise tracking. Herein, we report an activity-based two-photon fluorescent probe, TPSP-1, for the cascade detection of H2S and NAT2 in living liver cells. Continuous conversion from TPSP-1 to TPSP-3 was achieved in liver cells and tissues. Significantly, leveraging the outstanding optical properties of this two-photon fluorescent probe, TPSP-1, has been effectively used to identify pathological tissue samples directly from clinical liver cancer patients. This work provides us with this novel sensing and two-photon imaging probe, which can be used as a powerful tool to study the physiological functions of H2S and NAT2 and will help facilitate rapid and accurate diagnosis and therapeutic evaluation of hepatocellular carcinoma.

Relative apical sparing obtained with speckle tracking echocardiography is not a sensitive parameter for diagnosing light-chain cardiac amyloidosis.

Background: Distinguishing light-chain cardiac amyloidosis (AL CA) from left ventricular wall thickening (LVWT) resulted from other etiologies has proven to be challenging. This study aimed to determine the sensitivity and specificity of relative apical sparing in diagnosing AL CA and investigate the differences in clinical and echocardiographic characteristics between AL CA patients with apical sparing and those with non-apical sparing. Methods: A total of 63 consecutive patients with AL CA, 102 consecutive patients with LVWT (including 51 hypertrophic cardiomyopathy (HCM) and 51 hypertension) and 33 healthy individuals were recruited retrospectively at Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology. Conventional and speckle tracking echocardiography were performed on all subjects. Results: Although wall thickening was observed in all patients, almost all functional parameters were worse in AL CA, except for relative apical longitudinal strain (LS) (P=0.906). Of 63 patients with AL CA, only 17.5% (n=11) showed an apical sparing pattern. Patients with apical sparing had poorer cardiac performance than those with non-apical sparing. Relative apical sparing showed the lowest diagnostic accuracy with an area under the curve (AUC) of 0.58 [95% confidence interval (CI): 0.49-0.67, sensitivity: 17.5%, specificity: 98.0%, P=0.095] to detect AL CA, but right ventricular strain (RVS) (AUC: 0.86, P<0.001) showed the highest among all echocardiographic parameters. When diagnosing AL CA patients with non-apical sparing, RVS continued to maintain excellent diagnostic accuracy (AUC: 0.84, P<0.001), followed by left atrial reservoir strain (LASr) (AUC: 0.77, P<0.001). Conclusions: The diagnostic value of relative apical sparing for AL CA was limited with low sensitivity. In clinical practice, the diagnosis of early AL CA patients should not solely rely on relative apical sparing.

A novel dual serotonin transporter and M-channel inhibitor D01 for antidepression and cognitive improvement.

Cognitive dysfunction is a core symptom common in psychiatric disorders including depression that is primarily managed by antidepressants lacking efficacy in improving cognition. In this study, we report a novel dual serotonin transporter and voltage-gated potassium Kv7/KCNQ/M-channel inhibitor D01 (a 2-methyl-3-aryloxy-3-heteroarylpropylamines derivative) that exhibits both anti-depression effects and improvements in cognition. D01 inhibits serotonin transporters (Ki = 30.1 ± 6.9 nmol/L) and M channels (IC50 = 10.1 ± 2.4 µmol/L). D01 also reduces the immobility duration in the mouse FST and TST assays in a dose-dependent manner without a stimulatory effect on locomotion. Intragastric administrations of D01 (20 and 40 mg/kg) can significantly shorten the immobility time in a mouse model of chronic restraint stress (CRS)-induced depression-like behavior. Additionally, D01 dose-dependently improves the cognitive deficit induced by CRS in Morris water maze test and increases the exploration time with novel objects in normal or scopolamine-induced cognitive deficits in mice, but not fluoxetine. Furthermore, D01 reverses the long-term potentiation (LTP) inhibition induced by scopolamine. Taken together, our findings demonstrate that D01, a dual-target serotonin reuptake and M channel inhibitor, is highly effective in the treatment-resistant depression and cognitive deficits, thus holding potential for development as therapy of depression with cognitive deficits.

Improvements of myocardial strain and work in diabetes patients with normal ejection fraction after empagliflozin treatment.

AIMS/INTRODUCTION: To assess the effect of empagliflozin treatment on left ventricular (LV), right ventricular (RV) and left atrial (LA) functions in diabetes patients with normal ejection fraction. MATERIALS AND METHODS: The study included a total of 128 diabetes patients with multiple cardiovascular risk factors who were subjected to a 6-month follow up from the initiation of empagliflozin treatment. Before and after treatment with empagliflozin, LV, RV and LA strain, and noninvasive myocardial work parameters were evaluated by speckle tracking echocardiography. RESULTS: In 128 diabetes patients (mean age 56 ± 8 years, 85 men) with multiple cardiovascular risk factors, myocardial strain and work parameters were impaired, despite the absence of significant clinical symptoms of heart failure. After 6-month treatment with empagliflozin, the absolute value of LV strain in all directions increased, represented by LV global longitudinal strain (-18.0 ± 1.7% to -19.2 ± 1.7% [mean ± SD]). The same trend in LV global work efficiency (93 [91-94] % to 94 [93-95] % [median (IQR)]), RV free-wall longitudinal strain (-24.0 ± 2.7% to -25.0 ± 2.8%), LA reservoir (31 ± 5% to 34 ± 5%) and conduit strain (-14 ± 4% to -16 ± 4%) was also observed. LV mass index (106.9 ± 16.8-103.6 ± 16.4 g/m2) and LV global wasted work (143 [111-185] mmHg% to 108 [88-141] mmHg%) decreased after treatment (P < 0.05 for all). LV volume and LA volume index remained unchanged after treatment. In the multivariable analysis, the change in LA reservoir strain (ß = 0.050, P = 0.035) and baseline global longitudinal strain (ß = -0.488, P < 0.001) were independent predictors of improvement in LV global longitudinal strain. CONCLUSIONS: This study suggests that 6-month treatment with empagliflozin improved LV, RV and LA functions in diabetes patients with normal ejection fraction.

Vancomycin relieves tacrolimus-induced hyperglycemia by eliminating gut bacterial beta-glucuronidase enzyme activity.

Up to 40% of transplant recipients treated long-term with tacrolimus (TAC) develop post-transplant diabetes mellitus (PTDM). TAC is an important risk factor for PTDM, but is also essential for immunosuppression after transplantation. Long-term TAC treatment alters the gut microbiome, but the mechanisms of TAC-induced gut microbiota in the pathogenesis of PTDM are poorly characterized. Here, we showed that vancomycin, an inhibitor of bacterial beta-glucuronidase (GUS), prevents TAC-induced glucose disorder and insulin resistance in mice. Metagenomics shows that GUS-producing bacteria are predominant and flourish in the TAC-induced hyperglycemia mouse model, with upregulation of intestinal GUS activity. Targeted metabolomics analysis revealed that in the presence of high GUS activity, the hydrolysis of bile acid (BAs)-glucuronic conjugates is increased and most BAs are overproduced in the serum and liver, which, in turn, activates the ileal farnesoid X receptor (FXR) and suppresses GLP-1 secretion by L-cells. The GUS inhibitor vancomycin significantly eliminated GUS-producing bacteria and inhibited bacterial GUS activity and BAs levels, thereby enhancing L-cell GLP-1 secretion and preventing hyperglycemia. Our results propose a novel clinical strategy for inhibiting the bacterial GUS enzyme to prevent hyperglycemia without requiring withdrawal of TAC treatment. This strategy exerted its effect through the ileal bile acid-FXR-GLP-1 pathway.

Allosteric Activation of α7 Nicotinic Acetylcholine Receptors by Novel 2-Arylamino-thiazole-5-carboxylic Acid Amide Derivatives for the Improvement of Cognitive Deficits in Mice.

Enhancing α7 nAChR function serves as a therapeutic strategy for cognitive disorders. Here, we report the synthesis and evaluation of 2-arylamino-thiazole-5-carboxylic acid amide derivatives 6-9 that as positive allosteric modulators (PAMs) activate human α7 nAChR current expressed in Xenopus ooctyes. Among the 4-amino derivatives, a representative atypical type I PAM 6p exhibits potent activation of α7 current with an EC50 of 1.3 µM and the maximum activation effect on the current over 48-fold in the presence of acetylcholine (100 µM). The structure-activity relationship (SAR) analysis reveals that the 4-amino group is crucial for the allosteric activation of α7 currents by compound 6p as the substitution of 4-methyl group results in its conversion to compound 7b (EC50 = 2.1 µM; max effect: 58-fold) characterized as a typical type I PAM. Furthermore, both 6p and 7b are able to rescue auditory gating deficits in mouse schizophrenia-like model of acoustic startle prepulse inhibition.

Inhibition of Cardiac Kv4.3/KChIP2 Channels by Sulfonylurea Drug Gliquidone.

The Kv4.3 channel features fast N-type inactivation and also undergoes a slow C-type inactivation. The gain-of-function mutations of Kv4.3 channels cause an inherited disease called Brugada syndrome (BrS), characterized by a shortened duration of cardiac action potential repolarization and ventricular arrhythmia. The sulfonylurea drug gliquidone, an ATP-dependent K+ channel antagonist, is widely used for the treatment of type 2 diabetes. Here, we report a novel role of gliquidone in inhibiting Kv4.3 and Kv4.3/KChIP2 channels that encode the cardiac transient outward K+ currents responsible for the initial phase of action potential repolarization. Gliquidone results in concentration-dependent inhibition of both Kv4.3 and Kv4.3/KChIP2 fast or steady-state inactivation currents with an IC50 of approximately 8 µM. Gliquidone also accelerates Kv4.3 channel inactivation and shifts the steady-state activation to a more depolarizing direction. Site-directed mutagenesis and molecular docking reveal that the residues S301 in the S4 and Y312A and L321A in the S4-S5 linker are critical for gliquidone-mediated inhibition of Kv4.3 currents, as mutating those residues to alanine significantly reduces the potency for gliquidone-mediated inhibition. Furthermore, gliquidone also inhibits a gain-of-function Kv4.3 V392I mutant identified in BrS patients in voltage- and concentration-dependent manner. Taken together, our findings demonstrate that gliquidone inhibits Kv4.3 channels by acting on the residues in the S4 and the S4-S5 linker. Therefore, gliquidone may hold repurposing potential for the therapy of Brugada syndrome. SIGNIFICANCE STATEMENT: We describe a novel role of gliquidone in inhibiting cardiac Kv4.3 currents and the channel gain-of-function mutation identified from patients with Brugada syndrome, suggesting its repurposing potential for therapy for the heart disease.

Incremental prognostic utility of left ventricular and left atrial strains in coronary artery disease patients with reduced systolic function.

OBJECTIVE: This study aimed to investigate the predictive value of left ventricular global longitudinal strain (GLS) and left atrial reservoir strain (LARS) on adverse events in chronic coronary artery disease (CAD) patients with reduced systolic function. METHODS: A total of 192 consecutive patients clinically diagnosed with chronic CAD and left ventricular ejection fraction (LVEF) ≤ 50% were finally included. Multiple strain parameters were analyzed with speckle tracking echocardiography. The composite endpoint included all-cause mortality, rehospitalization due to heart failure, myocardial infarction, and stroke. RESULTS: Patients experiencing the endpoint showed lower LVEF, lower absolute GLS and LARS than those without events. Both GLS (AUC = 0.82 [GLS] vs. 0.58 [LVEF], p < 0.001) and LARS (AUC = 0.71 [LARS] vs. 0.58 [LVEF], p = 0.033) were superior to LVEF in predicting adverse events. Multivariate cox regression analysis showed that both GLS (hazard ratio, 0.71; 95% CI, 0.63-0.79; p < 0.001) and LARS (hazard ratio, 0.96; 95% CI, 0.93-0.98; p < 0.001) were independent predictors for the endpoint. The addition of LARS (global chi-squared, 35.7 vs. 17.4; p < 0.05), GLS (global chi-squared, 58.6 vs. 17.4; p < 0.05) or both LARS and GLS (global chi-squared, 79.6 vs. 17.4; p < 0.05) to LVEF in the prediction model significantly improved its performance. The same significant improvement was also shown in the subgroups of mild (30% < LVEF ≤ 50%) and severe (LVEF ≤ 30%) reduced systolic function. CONCLUSIONS: Regarding CAD patients with reduced LVEF, both GLS and LARS are superior to LVEF in predicting adverse events, providing significant incremental value to LVEF.

Effect of serum uric acid and gout on the incidence of colorectal cancer: A meta-analysis.

OBJECTIVE: Pathogenesis of colorectal cancer (CRC) depends on multiple factors. Identifying risk factors for CRC may facilitate the early prevention of the disease. We aimed to assess whether existing evidence suggests that serum uric acid (SUA) levels and gout are associated with CRC incidence. METHODS: The study was registered on PROSPERO (CRD42022371591). Searches of PubMed, Embase, and Cochrane Library were conducted from the establishment to November 11, 2022. Pooled relative risk (RR) with 95 % confidence intervals (CI) was derived to evaluate the effect of SUA or gout on CRC incidence. Non-linear trend analysis was conducted to explore the relationship between SUA level and CRC incidence. RESULTS: Twelve eligible studies with 22 reports were included. A meta-analysis of the included studies showed that when the highest and lowest SUA level categories were compared, an association between SUA level and CRC incidence was revealed (RR, 1.35; 95 % CI: 1.27-1.43; P < 0.001). Non-linear relationship between SUA level and CRC incidence was found. Further meta-analysis indicated that gout was associated with CRC incidence (RR, 1.22; 95 % CI: 1.08-1.36; P = 0.001). CONCLUSIONS: Both SUA level and gout were associated with an increased risk of CRC. Maintaining low SUA levels may be beneficial in reducing the incidence of CRC. Further studies evaluating the precise mechanisms underlying this association are needed to establish whether SUA/gout causes CRC.

Intracellular tacrolimus concentration correlates with impaired renal function through regulation of the IS-AHR-ABC transporter in peripheral blood mononuclear cells.

BACKGROUNDS: Tacrolimus (TAC) concentration in peripheral blood mononuclear cells (PBMCs) is regarded as a better predictor of its immunosuppressive effect than the TAC concentration in whole blood. However, whether the exposure of TAC in PBMCs or WB was altered in post-transplant recipients with renal impairment remains unclear. METHODS: We investigated the relationship of trough TAC concentration in WB and PBMCs with renal functions in post-transplant recipients. The pharmacokinetic profiles of TAC in PBMCs and WB in the two chronic kidney disease (CKD) rat models were examined using UPLC-MS/MS. Western blotting and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were used to analyze the expression of proteins and mRNAs related to TAC metabolism and transport, respectively. In addition, the effects of uremic toxins on human PBMCs were investigated using whole-transcriptome sequencing (RNA sequencing [RNA-seq]). RESULTS: We observed a decrease in the trough TAC concentration in PBMCs in the recipients with estimated glomerular filtration rate (eGFR) < 90 mL/min, compared with those of recipients with eGFR > 90 mL/min, but there was no difference in blood based on TAC concentrations (C0Blood). In a 150-patient post-transplant cohort, no significant relationship was observed between PBMCs and WB concentrations of TAC, and the eGFR value was correlated with TAC C0PBMCs but not with TAC C0Blood. In two CKD rat models, the TAC pharmacokinetic profile in the PBMCs was significantly lower than that in the control group; however, the blood TAC pharmacokinetic profiles in the two groups were similar. Transcriptome results showed that co-incubation of human PBMCs with uremic toxins upregulated the expression of AHR, ABCB1, and ABCC2. Compared to control rats, plasma IS increased by 1.93- and 2.26-fold and the expression of AHR, P-gp, and MRP2 in PBMCs was higher in AD and 5/6 nephrectomy (NX) rats, without modifying the expression of other proteins related to TAC exposure. CONCLUSION: The pharmacokinetics of TAC in PBMCs changed with a decline in renal function. Uremic toxins accumulate during renal insufficiency, which activates AHR, upregulates the expression of P-gp and MRP2, and affects their intracellular concentrations. Our findings suggest that monitoring TAC concentrations in PBMCs is more important than monitoring WB concentrations in post-transplant recipients with renal impairment.

Association between gout and the risk of osteoporosis and fractures: a meta-analysis.

OBJECTIVE: The relationship between gout and osteoporosis is poorly clarified, and the association between gout and fractures incidence remains controversial. Hence, in the present study, we aimed to comprehensively evaluate the available literature to elucidate whether gout is associated with an increased risk of both osteoporosis and fractures. MATERIALS AND METHODS: We conducted an exhaustive search of pertinent literature published until 20 March 2023, in well-recognized databases, namely Medline, Embase and Cochrane Library, focusing on examining the association between gout and the risk of osteoporosis or fracture. Meta-analysis was performed to aggregate the relative risks (RR) using random- or fixed-effects models. Sensitivity analyses were conducted iteratively, whereby each study was removed sequentially to gauge its impact on the overall outcome. Publication bias was assessed using Egger's and Begg's tests. This study was registered with PROSPERO (registry number: CRD42022376822). RESULTS: Herein, we included 10 observational studies comprising a total of 1,606,095 participants. An independent population sample of four studies validated the significant association between gout and osteoporosis (RR = 1.25, 95% confidence interval [CI] 1.05-1.48), with the results demonstrating robustness. However, our analysis did not detect any association between gout and fracture risk when compared with the control group (RR = 1.09, 95%CI 0.99-1.19), along with high heterogeneity (p for heterogeneity = 0.000; I2 = 79.7%). Further subgroup analysis revealed that gout is positively associated with fracture risk in the Chinese population (RR = 1.17, 95%CI 1.14-1.21), with no evidence of heterogeneity (p for heterogeneity = 0.420; I2 = 0.00%). CONCLUSION: Our meticulous evaluation of the available literature indicates that gout has no discernible impact on fracture incidence, although it is positively associated with an enhanced risk of osteoporosis. Therefore, it is imperative to prioritize preventive measures to prevent osteoporotic complications in individuals diagnosed with gout.

Pure Laparoscopic Anatomic Resection of Liver Segment 4 with Middle Hepatic Vein Involvement Using Indocyanine Green Fluorescence Staining.

BACKGROUND: Laparoscopic anatomic resection of liver segment 4 is a technically challenging operation, which is rarely reported owing to the difficulty of defining the demarcation of a hepatic segment 4 on a monitor.1 The portal territory staining method is technically feasible to identify tumors and segment boundaries during hepatectomy.2 Herein, we describe the laparoscopic hepatectomy of segment 4 using the fluorescent-positive staining method. METHODS: A 72-year-old man recurred colorectal liver metastases after colectomy, positron emission tomography (PET)/computed tomography (CT) showed metastases located in segment 4 with involvement of the middle hepatic vein (MHV) and caudate lobe; no other organ metastasis or recurrence occurred. We performed an anatomical hepatectomy 4 with MHV and parenchymal resection of segment 1 (H1'/4-MHV).3 The key point of the procedure was dividing and clamping Glisson's branches for segment 2 and segment 3 using the hepatic round ligament approach; the G2 and G3 were dissected along the right side of round ligament via the extrahepatic Glissonian approach, then the left hepatic artery (LHA) was divided and injected with ICG in the left portal vein (LPV). Finally, transection was performed along the fluorescent stain location line and ischemic demarcation line. RESULTS: The operation time was 263 min; the Pringle lasted 110 min, and the estimated blood loss was 400 g. The patient was discharged on postoperative day 5 without complications. Sigmoid carcinoma and R0 margin were confirmed by histopathology. CONCLUSIONS: Laparoscopic anatomic hepatectomy 4 with middle hepatic vein invasion using indocyanine green (ICG) fluorescence staining is a feasible and effective technique.

A novel model to predict the risk of hematological toxicity in lung adenocarcinoma patients with pemetrexed plus platinum chemotherapy based on real-world data.

BACKGROUND: Pemetrexed plus platinum chemotherapy is the first-line treatment option for lung adenocarcinoma. However, hematological toxicity is major dose-limiting and even life-threatening. The ability to anticipate hematological toxicity is of great value for identifying potential chemotherapy beneficiaries with minimal toxicity and optimizing treatment. The study aimed to develop and validate a prediction model for hematologic toxicity based on real-world data. METHODS: Data from 1754 lung adenocarcinoma patients with pemetrexed plus platinum chemotherapy regimen as first-line therapy were used to establish and calibrate a risk model for hematological toxicity using multivariate and stepwise logistic regression analysis based on real-world data. The predictive performance of the model was tested in a validation cohort of 753 patients. An area under the curve (AUC) of the receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis were used to assess the prediction model. RESULTS: 5 independent factors (platinum, pre-use vitamin B12, cycle of chemotherapy before hematological toxicity, Hb before first chemotherapy, and PLT before first chemotherapy) identified from multivariate and stepwise logistic regression analysis were included in the prediction model. The hematological toxicity prediction model achieved a sensitivity of 0.840 and a specificity of 0.822. The model showed good discrimination in both cohorts (an AUC of 0.904 and 0.902 for the derivation and validation cohort ROC) at the cut-off value of 0.591. The calibration curve showed good agreement between the actual observations and the predicted results. CONCLUSION: We developed a prediction model for hematologic toxicity with good discrimination and calibration capability in lung adenocarcinoma patients receiving a pemetrexed plus platinum chemotherapy regimen based on real-world data.

Apical hypertrophic cardiomyopathy: pathophysiology, diagnosis and management.

Since the first description of apical hypertrophic cardiomyopathy (ApHCM) in 1976, contrasting information from all over the world has emerged regarding the natural history of the disease. However, the recommended guidelines on hypertrophic cardiomyopathy (HCM) pay a cursory reference to ApHCM, without ApHCM-specific recommendations to guide the diagnosis and management. In addition, cardiologists may not be aware of certain aspects that are specific to this disease subtype, and a robust understanding of specific disease features can facilitate recognition and timely diagnosis. Therefore, the review covers the incidence, pathogenesis, and characteristics of ApHCM and imaging methods. Echocardiography and cardiovascular magnetic resonance imaging (CMR) are the most commonly used imaging methods. Moreover, this review presents the management strategies of this heterogeneous clinical entity. In this review, we introduce a novel transapical beating-heart septal myectomy procedure for ApHCM patients with a promising short-time result.

Electronic Flat Band in Distorted Colouring Triangle Lattice.

Dispersionless flat bands (FBs) in momentum space, given rise to electron destructive interference in frustrated lattices, offer opportunities to enhance electronic correlations and host exotic many-body phenomena, such as Wigner crystal, fractional quantum hall state, and superconductivity. Despite successes in theory, great challenges remain in experimentally realizing FBs in frustrated lattices due to thermodynamically structural instability. Here, the observation of electronic FB in a potassium distorted colouring triangle (DCT) lattice is reported, which is supported on a blue phosphorene-gold network. It is verified that the interaction between potassium and the underlayer dominates and stabilizes the frustrated structures. Two-dimensional electron gas is modulated by the DCT lattice, and in turn results in a FB dispersion due to destructive quantum interferences. The FB exhibits suppressed bandwidth with high density of states, which is directly observed by scanning tunneling microscopy and confirmed by the first-principles calculation. This work demonstrates that DCT lattice is a promising platform to study FB physics and explore exotic phenomena of correlation and topological matters.

Development of a cryogen-free sub-3 K low-temperature scanning probe microscope by remote liquefaction scheme.

We developed a new scheme for cryogen-free cooling down to sub-3 K temperature range and ultra-low vibration level. An ultra-high-vacuum cryogen-free scanning probe microscope (SPM) system was built based on the new scheme. Instead of mounting a below-decoupled cryocooler directly onto the system, the new design was realized by integrating a Gifford-McMahon cryocooler into a separate liquefying chamber, providing two-stage heat exchangers in a remote way. About 10 L of helium gas inside the gas handling system was cooled, liquefied in the liquefying chamber, and then transferred to a continuous-flow cryostat on the SPM chamber through an ∼2 m flexible helium transfer line. The exhausted helium gas from the continuous-flow cryostat was then returned to the liquefying chamber for reliquefaction. A base temperature of ∼2.84 K at the scanner sample stage and a temperature fluctuation of almost within ±0.1 mK at 4 K were achieved. The cooling curves, tunneling current noise, variable-temperature test, scanning tunneling microscopy and non-contact atomic force microscopy imaging, and first and second derivatives of I(V) spectra are characterized to verify that the performance of our cryogen-free SPM system is comparable to the bath cryostat-based low-temperature SPM system. This remote liquefaction close-cycle scheme shows conveniency to upgrade the existing bath cryostat-based SPM system, upgradeability of realizing even lower temperature down to sub-1 K range, and great compatibility of other physical environments, such as high magnetic field and optical accesses. We believe that the new scheme could also pave a way for other cryogenic applications requiring low temperature but sensitive to vibration.

Evaluation of left atrial and ventricular remodeling in atrial fibrillation subtype by using speckle tracking echocardiography.

Background: Atrial fibrillation (AF) is associated with cardiac structural and functional remodeling. We investigated the left atrial (LA) and left ventricular (LV) changes in AF subtypes by using two-dimensional echocardiography strain techniques. Methods: The study population consisted of 102 subjects with sinus rhythm (control group) and 463 patients with AF, among which 284 patients had paroxysmal AF (PAF) and 179 patients had persistent AF (PerAF). A speckle tracking automatic functional imaging software was used to perform the strain analysis. Results: Patients with AF had dilated LA maximum and minimum volume, decreased LA reservoir strain, lower LV ejection fraction (LVEF), and impaired global longitudinal strain (GLS) compared to those of the sinus rhythm control group. In patients with PerAF, the LA maximum and minimum volumes were larger, and the LA reservoir strain [PAF vs. PerAF, 28% (21,33) vs. 19% (14, 28), P < 0.05], LVEF, and absolute GLS value (PAF vs. PerAF, -16.9 ± 3.3 vs. -14.1 ± 3.5%) were lower than those in patients with PAF. Patients with AF regardless of LA enlargement had decreased LA reservoir strain and lower LVEF and absolute GLS value than those in the sinus rhythm control group. Conclusion: Compared with those with normal sinus rhythm, patients with AF had dilated LA volume and impaired LA function, which were further worsened in patients with PerAF than those in patients with PAF. LA functional impairment occurred before LA enlargement. Left atrioventricular remodeling happened across different stages of AF development.

Calculation of excited states of monolayer TPPA-COF based on first principles.

Two-dimensional covalent organic frameworks (COFs) have always been a hot topic in condensed matter physics. Herein, the first 100 excited states of the TPPA-COF are calculated to investigate the optical absorption properties of the materials in the interval. The stable molecular structure of monolayer TPPA-COF is obtained by first-principles calculation, which can be regarded as a hexagon with an aperture size of 18.25 Å. By means of the band structure and density of state analysis, it is found that the monolayer band gap width of the TPPA-COF is 1.52 eV. All excited states of the TPPA-COF exhibit obvious pi → pi* (delocalized π to anti π) local excitation characteristics through analysing the spatial distribution of the electron-hole pairs of the 10 excited states with the highest oscillator strength among the first 100 excited states. In addition, the simulated UV-vis spectra show that the maximum absorption intensity of the TPPA-COF is about 357 684 mol-1 cm-1, indicating that the TPPA-COF is a potential light-absorbing material.

3D dynamic tracking Aß plaques in live brains using vinyl-bridged dyes with two-photon excitation/NIR emission and large Stokes shifts.

Real-time studies of biomarkers for neurological disorders present significant opportunities for diagnosing and treating related diseases, and fluorescent probes offer a promising approach to brain imaging. However, intracerebral fluorescence imaging is often limited by blood-brain barrier permeability and penetration depth. Moreover, only very few probes have rapid intracerebral metabolic properties, which are critical for in vivo imaging. Here, we developed a novel class of fluorescent dyes with two-photon excitation and near-infrared (NIR) emission (920/705 nm). The representative WAPP-4 probe exhibits a large Stokes shift (Δλ = 324 nm in ethanol) and excellent blood-brain barrier permeability. Notably, using WAPP-4, we achieved in vivo 3D dynamic imaging of Aß plaques in the brains of living mice with Alzheimer's disease (AD). In addition, super-resolution imaging showed that WAPP-4 could effectively characterize the distribution and shape of Aß plaques in isolated brain slices. This study demonstrates that newly developed fluorescent dyes with large Stokes shifts and blood-brain barrier permeability enable real-time imaging of amyloid plaques, which will contribute to the development of other valuable tools for near-infrared imaging and super-resolution imaging in the brain.