White Matter Hyperintensities on Post-Stroke Balance and Gait Recovery: A Prospective Cohort Study Protocol.

INTRODUCTION: White matter hyperintensities (WMH) are commonly associated with balance and gait disturbances. Little is known whether WMH may affect post-stroke balance and gait recovery. We aim to investigate the association of post-stroke balance and gait recovery with imaging marker of WMH on magnetic resonance imaging (MRI). METHODS: This prospective cohort study will enroll consecutive patients with first-ever ischemic hemisphere stroke, between September 2023 and December 2024. Clinical data will be collected on day 30±3 and at 3-month after stroke onset. WMH on FLAIR are graded according to the modified Fazekas scale. Resting-state functional MRI (rs-fMRI) and diffusion tensor imaging (DTI) will be acquired to evaluate functional and structural connectivity. The primary endpoint is balance recovery, defined as a Postural Assessment Scale for Stroke score of 32 or higher at 3-month. The secondary endpoint is gait recovery, assessed using the modified Fugl-Meyer Gait Assessment at 3-month. We will investigate the association of post-stroke balance and gait recovery with WMH severity as well as WMH-related functional and structural connectivity. CONCLUSION: The study may contribute to clarify the effect of WMH on post-stroke balance and gait disorder recovery.

Improving the voltage tolerance of perovskite light-emitting diodes via a charge-generation layer.

A high electrical field is necessary to achieve a high brightness for halide perovskite light-emitting diodes (PeLEDs). Charge accumulation in the perovskite film becomes more serious under a high electrical field owing to the imbalanced charge injection in PeLEDs. Concomitantly, the perovskite film will suffer from a higher electrical field increased by the accumulated-charge-induced local electrical field, dramatically accelerating the ion migration and degradation of PeLEDs. Here we construct a voltage-dependent hole injection structure consisting of a ZnO/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) bilayer, which can properly adjust the hole injection according to the driving electrical field, matching with the injected electrons. As a result, the ZnO/PEDOT:PSS-containing PeLED can be operated under higher driving voltage with a higher peak brightness of 18920 cd/m2, which is 84% higher than the reference device based on a PEDOT:PSS single layer. Moreover, the ZnO/PEDOT:PSS-containing PeLED delivers a much higher power efficiency than the reference device under high driving voltages.

Determinants for a low dose of alteplase and its relationship to a lower intracerebral bleeding risk in acute ischemic stroke.

Background: Factors for the utilization of intravenous thrombolysis with a low-dose of alteplase (0.6mg/kg) and whether the low-dose of alteplase could reduce the risk of intracerebral bleeding in acute ischemic stroke (AIS) remains uncertain. Aims: We aimed to investigate determinants for the utilization of intravenous thrombolysis with a low-dose of alteplase. We further assessed the association between the low-dose of alteplase and the intracerebral bleeding risk in AIS patients. Method: We included AIS patients who received intravenous thrombolysis using alteplase in this multicenter retrospective observational study. We investigated the association between baseline characteristics and the utilization of a low-dose of alteplase to identify determinants. We assessed the association of the low-dose of alteplase with the risk of symptomatic intracranial hemorrhage (sICH) using a multivariable logistic regression model. We further compared the rate of sICH and any ICH in patients in the low-dose group to those in the standard-dose group, using propensity score-matching data. Results: A total of 506 AIS patients were included in this study. The mean age was 67 (interquartile range [IQR] 59-75), and 178 (35.2%) were women. A total of 96 patients were treated with the low-dose. Age (adjusted odds ratio [OR] 1.02, 95% confidence interval [CI] 1.00 -1.04, p = 0.042), having a previous ischemic stroke (adjusted OR 2.01, 95%CI 1.11 - 3.64 p = 0.021) and increasing baseline systolic blood pressure (adjusted OR 1.12, 95%CI 1.00 - 1.26, p = 0.049) were determinants for the utilization of the low-dose. Multivariable logistic regression analysis showed that the low-dose was significantly associated with a reduced risk of sICH (adjusted OR 0.13, 95%CI 0.03 - 0.62, p = 0.01). Propensity score analysis showed that the rate of sICH was significantly lower in the low-dose group compared to standard-dose group (2 [2.3%] vs 10 [11.4%], p = 0.032). There was no significant difference in the rate of any ICH between two groups (14 [15.9%] vs 18 [20.5%], p = 0.434). Conclusions: Patients with increasing age, a higher baseline systolic blood pressure, and previous ischemic stroke were at a higher odd of receiving a low-dose of alteplase. The low-dose was associated with a lower risk of developing symptomatic intracranial hemorrhage.

Exploring the emission mechanism of dichromatic white-light quantum-dot light-emitting diodes using wavelength-resolved transient electroluminescence analysis.

Exploring electroluminescence (EL) processes is extremely vital to fabricate efficient white-light quantum-dot light-emitting diodes (QLEDs). A model white QLED consisting of a bilayer CdSe/ZnSeS quantum-dot (QD)//CuInS2/ZnS QDs emissive layer has been used to analyze the white-light emission mechanism. In this design, the CdSe/ZnSeS QDs and CuInS2/ZnS QDs contribute to the blue and yellow emissions, respectively, in the dichromatic white QLED. Wavelength-resolved transient EL (TrEL) results demonstrate that the excitons are mainly formed on the CuInS2/ZnS QDs in the QLED operated at low biases due to the low barrier to hole injection and energy transfer from the CdSe/ZnSeS QDs to the CuInS2/ZnS QDs. Further, the TrEL decays of both white and monochromic devices reveal that the emission behavior of the white QLED is closely related to that of the monochromic device, but is minimally affected by the interactions between different emission units. The simulation results performed by the solar cell capacitance simulator model agree well with the experimental data. Our results show an insight into the EL processes in the white device QLED and demonstrate a powerful tool to investigate emission behavior of the white QLEDs.

Activation of mGluR5 Attenuates Microglial Activation and Neuronal Apoptosis in Early Brain Injury After Experimental Subarachnoid Hemorrhage in Rats.

Activation of metabotropic glutamate receptor 5 (mGluR5) provided neuroprotection in multiple central nervous system injury, but the roles of mGluR5 in subarachnoid hemorrhage (SAH) remain unclear. In present study, we aimed to evaluate whether activation of mGluR5 attenuates early brain injury (EBI) after experimental SAH in rats. We found that selective mGluR5 orthosteric agonist CHPG or positive allosteric modulator VU0360172 administration significantly improves neurological function and attenuates brain edema at 24 h after SAH. Furthermore, mGluR5 obviously expresses in activated microglia (ED-1 positive) after SAH. CHPG or VU0360172 administration significantly reduces the numbers of activated microglia and the protein and mRNA levels of pro-inflammatory cytokines IL-1ß, IL-6 and TNF-α at 24 h after SAH. Moreover, CHPG or VU0360172 administration obviously reduces the number of TUNEL-positive cells and active caspase-3/NeuN-positive neurons in cortex at 24 h after SAH. CHPG or VU0360172 administration significantly up-regulates the expression of Bcl-2, and down-regulates the expression of Bax and active caspase-3, which in turn increases the ratio of Bcl-2/Bax. Our results indicate that activation of mGluR5 attenuates microglial activation and neuronal apoptosis, and improves neurological function in EBI after SAH.

Association between atrial cardiopathy and stroke severity in acute ischemic stroke.

In this hospital-based cross-sectional analytic study, we retrospectively reviewed clinical data of patients with acute ischemic stroke (AIS) between January 2017 and April 2023. Atrial cardiopathy was defined as any presence of the following: left atrial diameter ≥ 52 mm (males) or ≥ 47 mm (females), elevated P-wave terminal force in V1 > 5000 µV ms, or serum N terminal pro B type natriuretic peptide > 250 pg/ml. Initial stroke severity was defined by the National Institutes of Health Stroke Scale (NIHSS; moderate-to-severe, ≥ 5; and severe, ≥ 15). Univariate and multivariate binary logistic regression analyses were performed to assess the association between atrial cardiopathy and stroke severity. Among 662 AIS patients (mean age 70 years [interquartile range 61-78], 31.3% women), 303 (45.8%) had atrial cardiopathy. Multivariable logistic regression analysis showed that the presence of atrial cardiopathy was significantly associated with a higher odd of moderate-to-severe stroke (adjusted odds ratio [OR] 2.16, 95% confidence interval [CI] 1.46-3.20, p < 0.001) and severe stroke (adjusted OR 4.89, 95%CI 2.45-9.76, p < 0.001). This association remained significant in a sensitivity analysis excluding those with atrial fibrillation or coronary artery disease. Findings of the current study revealed that the association of atrial cardiopathy was with initial stroke severity independent of atrial fibrillation and was even confirmed in patients without atrial fibrillation; future studies to explore improved stroke prevention strategies for patients with atrial cardiopathy are needed.

Sex difference in the association between triglyceride and intracerebral bleeding risk after intravenous thrombolysis for acute ischemic stroke, a multi-center retrospective study.

Background: Whether the relationship of intracerebral bleeding risk with lipid profile may vary by sex remains unclear. This study aims to investigate potential sex differences in the association between lipid profile and the risk of symptomatic intracerebral hemorrhage (sICH) in patients with acute ischemic stroke (AIS) who received intravenous thrombolysis using recombinant tissue plasminogen activator (r-tPA). Methods: This multicenter retrospective observational study analyzed patients with AIS treated with intravenous r-tPA. sICH was defined as a worsening of 4 or higher points in the National Institutes of Health Stroke Scale (NIHSS) score within 36 hours after intravenous thrombolysis in any hemorrhage subtype. We assessed the odds ratio (OR) with 95% confidence interval (CI) of lipid profile for sICH for each sex using logistic regression models adjusted for potential confounding factors. Results: Of 957 participants (median age 68 (interquartile range, 59-75), men 628 (65.6%)), 56 sICH events (36 (5.7%) in men and 20 (6.1%) in women) were observed. The risk of sICH in men decreased with increasing serum levels of triglyceride after adjustment for confounding factors (vs lowest tertile, medium tertile OR 0.39, 95% CI [0.17-0.91], top tertile OR 0.33, 95% CI [0.13-0.84], overall p = 0.021; per point increase, adjusted OR 0.29, 95% CI [0.13-0.63], p = 0.002). Neither serum levels of total cholesterol nor low-density lipoprotein (LDL) was associated with sICH in men. In women, there was no association between any of the lipid levels and the risk of sICH. Conclusions: This study indicated that the association between serum levels of triglyceride and sICH may vary by sex. In men, increased triglyceride levels decrease the risk of sICH; in women, this association was lost. Further studies on the biological mechanisms for sex differences in stroke risk associated with triglyceride are needed.

Electronic and Excitonic Processes in Quantum Dot Light-Emitting Diodes.

A modified Langevin model has been proposed to study the electronic and excitonic dynamic processes in quantum dot light-emitting diodes (QLEDs), and the electroluminescence onset processes of the QLEDs under different charge-injection conditions have been explored. The simulation results are in good agreement with experimental curves, confirming the feasibility of this model. It is demonstrated that the formation of an exciton on the quantum dots (QDs) with one electron injected first followed by one hole is much more effective than that with the reverse sequence. That is, charging a QD with one electron first is more favorable for device performance enhancement, which is attributed to the low (high) Auger recombination rate of negative (positive) trions of commonly used type I QDs. Additionally, we demonstrate that enough electron injection is one of the prerequisites for high-performance QLEDs based on these type I QDs.

Facial emotion perception and recognition deficits in acute ischemic stroke.

BACKGROUND: Facial emotion perception and recognition (FEPR) deficits are the sources of disability, impaired social relationship, and reduced quality of life. Studies of unilateral acute ischemic stroke (AIS) remain controversial about FEPR deficits. METHODS: Clinical and neurocognitive data were collected and analyzed among normal controls (NC) and AIS patients with left brain damage (LBD), right brain damage (RBD), and infratentorial brain damage (IBD). To assess FEPR, all participants completed a localization test (the Southeastern China Brief Affect Recognition Test). Correlation analyses were conducted between the FEPR deficits and cognitive functions. RESULTS: Compared with NC, all three groups of AIS patients reported significant FEPR deficits. Although no statistical difference in FEPR deficits were observed among the LBD, RBD and IBD patients, the deficit patterns were markedly different. FEPR deficits were positively correlated with cognitive impairment. CONCLUSIONS: FEPR deficits may occur in AIS patients and are associated with impaired cognitive functions, where the cerebral hemispheres and the infratentorial brain are jointly involved. Early recognition and early intervention of FEPR deficits in AIS patients are critical for post-stroke rehabilitation, reconstruction of social function and improvement in life quality.

Association Between Previous Stroke and Severe COVID-19: A Retrospective Cohort Study and an Overall Review of Meta-Analysis.

Objective: The objective of this study was to investigate the association between previous stroke and the risk of severe coronavirus disease 2019 (COVID-19). Methods: We included 164 (61.8 ± 13.6 years) patients with COVID-19 in a retrospective study. We evaluated the unadjusted and adjusted associations between previous stroke and severe COVID-19, using a Cox regression model. We conducted an overall review of systematic review and meta-analysis to investigate the relationship of previous stroke with the unfavorable COVID-19 outcomes. Results: The rate of severe COVID-19 in patients with previous stroke was 28.37 per 1,000 patient days (95% confidence interval [CI]: 10.65-75.59), compared to 3.94 per 1,000 patient days (95% CI: 2.66-5.82) in those without previous stroke (p < 0.001). Previous stroke was significantly associated with severe COVID-19 using a Cox regression model (unadjusted [hazard ratio, HR]: 6.98, 95% CI: 2.42-20.16, p < 0.001; adjusted HR [per additional 10 years]: 4.62, 95% CI: 1.52-14.04, p = 0.007). An overall review of systematic review and meta-analysis showed that previous stroke was significantly associated with severe COVID-19, mortality, need for intensive care unit admission, use of mechanical ventilation, and an unfavorable composite outcome. Conclusion: Previous stroke seems to influence the course of COVID-19 infection; such patients are at high risk of severe COVID-19 and might benefit from early hospital treatment measures and preventive strategies.

Total Cerebral Small Vessel Disease Score and Cerebral Bleeding Risk in Patients With Acute Stroke Treated With Intravenous Thrombolysis.

Objective: The aim of this study was to investigate the association of total cerebral small vessel disease (cSVD) score with the risk of intracerebral hemorrhage (ICH) in patients with acute ischemic stroke who received intravenous thrombolysis (IVT) using recombinant tissue-plasminogen activator (rt-PA). Methods: We retrospectively reviewed clinical data from two stroke registries of patients with acute ischemic stroke treated with IVT. We assessed the baseline magnetic resonance (MR) visible cSVD markers and total cSVD score (ranging from 0 to 4) between patients with and without ICH after IVT. Logistic regression analysis was used to determine the association of total cSVD score with the risk of ICH after IVT, adjusted for cofounders selected by least absolute shrinkage and selection operator (LASSO). We additionally performed an E-value analysis to fully explain away a specific exposure-outcome association. Receiver operating characteristic (ROC) curve analysis was used to quantify the predictive potential of the total cSVD score for any ICH after IVT. Results: Among 271 eligible patients, 55 (20.3%) patients experienced any ICH, 16 (5.9%) patients experienced a symptomatic ICH (sICH), and 5 (1.85%) patients had remote intracranial parenchymal hemorrhage (rPH). Logistic regression analysis showed that the risk of any ICH increased with increasing cSVD score [per unit increase, adjusted odds ratio (OR) 2.03, 95% CI 1.22-3.41, P = 0.007]. Sensitivity analyses using E-value revealed that it would need moderately robust unobserved confounding to render the exposure-outcome (cSVD-any ICH) association null. ROC analysis showed that compared with the National Institutes of Health Stroke Scale (NIHSS) score alone, a combination of cSVD and NIHSS score had a larger area under the curve for any ICH (0.811, 95% CI 0.756-0.866 vs. 0.784, 95% CI 0.723-0.846, P = 0.0004). Conclusion: The total cSVD score is associated with an increased risk of any ICH after IVT and improves prediction for any ICH compared with NIHSS alone.

Intravenous Thrombolysis Before Mechanical Thrombectomy for Acute Ischemic Stroke: A Meta-Analysis.

Background Whether intravenous thrombolysis before mechanical thrombectomy provides additional benefit for functional outcome in acute ischemic stroke remains uncertain. We performed a meta-analysis to compare the outcomes of direct mechanical thrombectomy (dMT) to mechanical thrombectomy with bridging using intravenous thrombolysis (bridging therapy [BT]) in patients with acute ischemic stroke. Methods and Results We performed a literature search in the PubMed, Excerpta Medica database, and Cochrane Central Register of Controlled Trials from January 1, 2003, to April 26, 2021. We included randomized clinical trials and observational studies that reported the 90-day functional outcome in patients with acute ischemic stroke undergoing dMT compared with BT. The 12 included studies (3 randomized controlled trials and 9 observational studies) yielded 3924 participants (mean age, 68.0 years [SD, 13.1 years]; women, 44.2%; 1887 participants who received dMT and 2037 participants who received BT). A meta-analysis of randomized controlled trial and observational data revealed similar 90-day functional independence (odds ratio [OR], 1.04; 95% CI, 0.90-1.19), mortality (OR, 1.03; 95% CI, 0.78-1.36), and successful recanalization (OR, 0.93; 95% CI, 0.76-1.14) for patients treated with dMT or BT. Compared with those in the BT group, patients in the dMT group were less likely to experience symptomatic intracranial hemorrhage (OR, 0.68; 95% CI, 0.51-0.91; P=0.008) or any intracranial hemorrhage (OR, 0.71; 95% CI, 0.61-0.84; P<0.001). Conclusions In this meta-analysis of patients with acute ischemic stroke, we found no significant differences in 90-day functional outcome or mortality between dMT and BT, but a lower rate of symptomatic intracranial hemorrhage for dMT. These findings support the use of dMT without intravenous thrombolysis bridging therapy. Registration URL: https://www.crd.york.ac.uk/prospero/; Unique identifier: 42021234664.

Does pre-existent physical inactivity have a role in the severity of COVID-19?

BACKGROUND AND AIMS: Physical inactivity is considered an important lifestyle factor for overweight and cardiovascular disease. We aimed to investigate the association between pre-existent physical inactivity and the risk of severe coronavirus disease 2019 (COVID-19). METHODS: We included 164 (61.8 ± 13.6 years) patients with COVID-19 who were admitted between 15 February and 14 March 2020 in this retrospective study. We evaluated the association between pre-existent physical inactivity and severe COVID-19 using a logistic regression model. RESULTS: Of 164 eligible patients with COVID-19, 103 (62.8%) were reported to be physically inactive. Univariable logistic regression analysis showed that physical inactivity was associated with an increased risk of severe COVID-19 [unadjusted odds ratio (OR) 6.53, 95% confidence interval (CI) 1.88-22.62]. In the multivariable regression analysis, physical inactivity remained significantly associated with an increased risk of severe COVID-19 (adjusted OR 4.12, 95% CI 1.12-15.14) after adjustment for age, sex, stroke, and overweight. CONCLUSION: Our data showed that pre-existent physical inactivity was associated with an increased risk of experiencing severe COVID-19. Our findings indicate that people should be encouraged to keep physically active to be at a lower risk of experiencing a severe illness when COVID-19 infection seems unpredicted.The reviews of this paper are available via the supplemental material section.

Efficiency Improvement of Quantum Dot Light-Emitting Diodes via Thermal Damage Suppression with HATCN.

With many advantages including superior color saturation and efficiency, quantum dot light-emitting diodes (QLEDs) are considered a promising candidate for the next-generation displays. Emission uniformity over the entire device area is a critical factor to the overall performance and reliability of QLEDs. In this work, we performed a thorough study on the origin of dark spots commonly observed in operating QLEDs and developed a strategy to eliminate these defects. Using advanced cross section fabrication and imaging techniques, we discovered the occurrence of voids in the organic hole transport layer and directly correlated them to the observed emission nonuniformity. Further investigations revealed that these voids are thermal damages induced during the subsequent thermal deposition of other functional layers and can act as leakage paths in the device. By inserting a thermo-tolerant 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HATCN) interlayer with an optimized thickness, the thermally induced dark spots can be completely suppressed, leading to a current efficiency increase by 18%. We further demonstrated that such a thermal passivation strategy can work universally for various types of organic layers with low thermal stability. Our findings here provide important guidance in enhancing the performances and reliability of QLEDs and also other sandwich-structured devices via the passivation of heat-sensitive layers.

Association Between Steno-Occlusive Middle Cerebral Artery and Basal Ganglia Perivascular Spaces.

Objectives: Enlarged perivascular spaces in the basal ganglia (BG-EPVS) share common vascular risk factors with atherosclerosis. However, little is known about the relationship between steno-occlusive middle cerebral artery (MCA) and BG-EPVS. In this cross-sectional study, we aimed to test the hypothesis that severe MCA stenosis or occlusion is associated with increased MRI-visible BG-EPVS. Methods: We retrospectively reviewed 112 patients with a steno-occlusive MCA from Fujian Medical University Union Hospital between January 2014 and December 2018. We rated BG-EPVS, white matter hyperintensities (WMH), and lacunes as markers of cerebral small vessel disease (CSVD) on magnetic resonance image (MRI). The severity of steno-occlusive MCA was assessed by computed tomography angiography (CTA) and was classified into moderate (50-69%), severe (70-99%), and occlusion (100%). We evaluated the association of steno-occlusive MCA for >10 BG-EPVS using logistic regression model adjusted for age, gender, hypertension, MR-visible WMH, and lacunes. We also compared the number of BG-EPVS between the affected side and unaffected side in patients with only unilateral steno-occlusive MCA. Results: In multivariable logistic regression analysis, age (OR = 1.07, 95%CI: 1.03-1.13, p = 0.003), hypertension (OR = 2.77, 95%CI: 1.02-7.51, p = 0.046), severe MCA stenosis (OR = 3.65, 95%CI: 1.12-11.87, p = 0.032), or occlusion (OR = 3.67, 95%CI: 1.20-11.27, p = 0.023) were significantly associated with >10 BG-EPVS. The number of BG-EPVS in the affected side was higher than the unaffected side in patients with severe MCA stenosis (12 [9-14] vs. 8 [6-11], p = 0.001) or occlusion (11 [7-14] vs. 8 [5-11], p = 0.028). Conclusions: BG-EPVS were more prevalent in patients with severe MCA atherosclerosis. Our findings suggest a biological link between severe steno-occlusive MCA and increased BG-EPVS. These results need confirmation in prospective studies.

IL-10 produces a dual effect on OGD-induced neuronal apoptosis of cultured cortical neurons via the NF-κB pathway.

As a classic immunoregulatory cytokine, interleukin-10 (IL-10) can provide in vivo and in vitro neuroprotection respectively during cerebral ischemia and after the oxygen-glucose deprivation (OGD)-induced injury. However, its role in cortical neuronal survival at different post-ischemic phases remains unclear. The current study found that IL-10 had distinct effects on the neuronal apoptosis at different OGD stages: at an early stage after OGD, IL-10 promoted the OGD-induced neuronal apoptosis in the cultured primary cortical neurons by activating p65 subunit, which up-regulated Bax expression and down-regulated Bcl-xL expression; at a late OGD stage, however, it attenuated the OGD-induced neuronal apoptosis by activating c-Rel, which up-regulated Bcl-xL expression and down-regulated Bax expression. The early-stage pro-apoptosis and late-stage anti-apoptosis were both partly abolished by PDTC, an NF-κB inhibitor, and promoted by PMA, an NF-κB activator. The optimal anti-apoptotic effect appeared when the cultured neurons were treated with IL-10 at 9-24 h after OGD. Taken together, our findings suggest that IL-10 exerts a dual effect on the survival of the cultured neurons by activating the NF-κB pathway at different stages after OGD injury and that PMA treatment at a late stage can facilitate the IL-10-conferred neuroprotection against OGD-induced neuronal injury.

Influence of Shell Thickness on the Performance of NiO-Based All-Inorganic Quantum Dot Light-Emitting Diodes.

The effect of shell thickness on the performance of all-inorganic quantum dot light-emitting diodes (QLEDs) is explored by employing a series of green quantum dots (QDs) (Zn xCd1- xSe/ZnS core/shell QDs with different ZnS shell thicknesses) as the emitters. ZnO nanoparticles and sol-gel NiO are employed as the electron and hole transport materials, respectively. Time-resolved and steady-state photoluminescence results indicate that positive charging processes might occur for the QDs deposited on NiO, which results in emission quenching of QDs and poor device performance. The thick shell outside the core in QDs not only largely suppresses the QD emission quenching but also effectively preserves the excitons in QDs from dissociation of electron-hole pairs when they are subjected to an electric field. The peak efficiency of 4.2 cd/A and maximum luminance of 4205 cd/m2 are achieved for the device based on QDs with the thickest shells (∼4.2 nm). We anticipate that these results will spur progress toward the design and realization of efficient all-inorganic QLEDs as a platform for the QD-based full-colored displays.

Netrin-1 Promotes Synaptic Formation and Axonal Regeneration via JNK1/c-Jun Pathway after the Middle Cerebral Artery Occlusion.

As a secreted axon guidance molecule, Netrin-1 has been documented to be a neuroprotective factor, which can reduce infarct volume, promote angiogenesis and anti-apoptosis after stroke in rodents. However, its role in axonal regeneration and synaptic formation after cerebral ischemic injury, and the related underlying mechanisms remain blurred. In this study, we used Adeno-associated vectors carrying Netrin-1 gene (AAV-NT-1) to up-regulate the expression level of Netrin-1 in rats' brain after middle cerebral artery occlusion (MCAO). We found that the up-regulated level of Netrin-1 and its receptor DCC promoted axonal regeneration and synaptic formation; the overexpression of Netrin-1 activated the JNK1 signaling pathway; these effects were partially reduced when JNK1 signaling pathway was inhibited by SP600125 (JNK specific inhibitor). Taken together, these findings suggest that Netrin-1 can facilitate the synaptic formation and axonal regeneration via the JNK1 signaling pathway after cerebral ischemia, thus promoting the recovery of neural functions.

Netrin-1 Prevents Rat Primary Cortical Neurons from Apoptosis via the DCC/ERK Pathway.

In the nervous system, Netrin-1 serves as a neural guide, mediating the neuronal development. However, it remains blurred whether Netrin-1 can protect neurons from apoptosis induced by cerebral stroke. In the current study, the cultured rat primary cortical neurons were transfected with Netrin-1-encoding lentivirus before the oxygen-glucose-deprivation (OGD) treatment. Cell death and apoptosis were evaluated by lactate dehydrogenase (LDH) release and flow cytometry. We found that Netrin-1 attenuated OGD-induced cell death and neuronal apoptosis at 24 h after OGD treatment, and that the overexpression of Netrin-1 activated the ERK signaling pathway. These effects were partly abolished by blocking its receptor deleted in colorectal cancer (DCC) or U0126, an inhibitor of the ERK signaling pathway. Netrin-1 overexpression in neurons elevated the expression of DCC, on mRNA level and protein level. Netrin-1 also reduced DNA damage. Taken together, our findings suggest that Netrin-1 attenuates cell death and neuronal apoptosis via the DCC/ERK signaling pathway in the cultured primary cortical neurons after OGD injury, which may involve the mediation of DNA damage in the neurons.

Allosteric control of an asymmetric transduction in a G protein-coupled receptor heterodimer.

GPCRs play critical roles in cell communication. Although GPCRs can form heteromers, their role in signaling remains elusive. Here we used rat metabotropic glutamate (mGlu) receptors as prototypical dimers to study the functional interaction between each subunit. mGluRs can form both constitutive homo- and heterodimers. Whereas both mGlu2 and mGlu4 couple to G proteins, G protein activation is mediated by mGlu4 heptahelical domain (HD) exclusively in mGlu2-4 heterodimers. Such asymmetric transduction results from the action of both the dimeric extracellular domain, and an allosteric activation by the partially-activated non-functional mGlu2 HD. G proteins activation by mGlu2 HD occurs if either the mGlu2 HD is occupied by a positive allosteric modulator or if mGlu4 HD is inhibited by a negative modulator. These data revealed an oriented asymmetry in mGlu heterodimers that can be controlled with allosteric modulators. They provide new insight on the allosteric interaction between subunits in a GPCR dimer.