Multihierarchical Regulation To Achieve Quantum Dot Nanospheres with a Photoluminescence Quantum Yield Close to 100.

Quantum dots (QDs) exhibit superior brightness and photochemical stability, making them the preferred option for highly sensitive single-molecule detection compared with fluorescent dyes or proteins. Nevertheless, their high surface energy leads to nonspecific adsorption and poor colloidal stability. In the past decades, we have found that QD-based fluorescent nanoparticles (FNs) can not only address these limitations but also enhance detection sensitivity. However, the photoluminescence quantum yield (PLQY) of FNs is significantly lower compared with that of original QDs. It is urgent to develop a strategy to solve the issue, aiming to further enhance detection sensitivity. In this study, we found that the decrease of PLQY of FNs prepared by free radical polymerization was attributed to two factors: (1) generation of defects that can cause nonradiative transitions resulting from QD-ligands desorption and QD-shell oxidation induced by free radicals; (2) self-absorption resulting from aggregation caused by incompatibility of QDs with polymers. Based on these, we proposed a multihierarchical regulation strategy that includes: (1) regulating QD-ligands; (2) precisely controlling free radical concentration; and (3) constructing cross-linked structures of polymer to improve compatibility and to reduce the formation of surface defects. It is crucial to emphasize that the simultaneous coordination of multiple factors is essential. Consequently, a world-record PLQY of 97.6% for FNs was achieved, breaking through the current bottleneck at 65%. The flexible application of this regulatory concept paves the way for the large-scale production of high-brightness QD-polymer complexes, enhancing their potential applications in sensitive biomedical detection.

[Effect of inhibiting miR-204 expression on the learning and memory abilities of neonatal rats with intrauterine growth restriction and related mechanism]. / 抑制miR-204è¡¨è¾¾å¯¹å®«å† å‘è‚²è¿Ÿç¼“æ–°ç”Ÿå¤§é¼ å­¦ä¹ è®°å¿†èƒ½åŠ›çš„å½±å“åŠç›¸å ³æœºåˆ¶.

OBJECTIVES: To investigate the effect of inhibiting miR-204 expression on the learning and memory abilities of neonatal rats with intrauterine growth restriction (IUGR) and related mechanism. METHODS: A rat model of IUGR was prepared by low-protein diet. The 3-day-old IUGR rats were divided into three groups: model, miRNA antagonist control and miR-204 antagonist, with 10 rats in each group. Ten normal neonatal rats served as the control group. Morris water maze test was used to measure the learning and memory abilities of the rats. Quantitative real-time PCR was used to measure the mRNA expression levels of miR-204 and brain-derived neurotrophic factor (BDNF) in the hippocampus. Nissl staining and TUNEL staining were used to observe the number of Nissl bodies and the apoptosis of cells in the hippocampus. Western blot was used to measure the expression levels of BDNF/TrkB signaling pathway-related proteins in the hippocampus. RESULTS: Compared with the control group, the model group had a significant increase in the escape latency and a significant reduction in the number of platform crossings (P<0.001). The model group also had significant increases in the apoptosis rate of cells and the expression level of miR-204 in hippocampal tissue (P<0.001), while the number of Nissl bodies, the mRNA expression level of BDNF, and the protein expression levels of BDNF, p-TrkB, and p-CREB in the model group were significantly reduced compared with the control group (P<0.001). After inhibition of the expression of miR-204, the number of Nissl bodies, the mRNA expression level of BDNF, and the protein expression levels of BDNF, p-TrkB, and p-CREB significantly increased, while the cell apoptosis rate and the expression level of miR-204 in the hippocampus significantly decreased. The escape latency was also reduced, while the number of platform crossings increased after inhibition of the expression of miR-204 (P<0.001). CONCLUSIONS: Inhibiting miR-204 can improve the learning and memory functions of neonatal rats with IUGR, possibly by targeted activation of the BDNF/TrkB signaling pathway.

Spectrally Combined Encoding for Profiling Heterogeneous Circulating Tumor Cells Using a Multifunctional Nanosphere-Mediated Microfluidic Platform.

Comprehensive phenotypic profiling of heterogeneous circulating tumor cells (CTCs) at single-cell resolution has great importance for cancer management. Herein, a novel spectrally combined encoding (SCE) strategy was proposed for multiplex biomarker profiling of single CTCs using a multifunctional nanosphere-mediated microfluidic platform. Different cellular biomarkers uniquely labeled by multifunctional nanosphere barcodes, possessing identical magnetic tags and distinct optical signatures, enabled isolation of heterogeneous CTCs with over 91.6 % efficiency and in situ SCE of phenotypes. By further trapping individual CTCs in ordered microstructures on chip, composite single-cell spectral signatures were conveniently and efficiently obtained, allowing reliable spectral-readout for multiplex biomarker profiling. This SCE strategy exhibited great potential in multiplex profiling of heterogeneous CTC phenotypes, offering new avenues for cancer study and precise medicine.

Ultrasmall Pb:Ag2 S Quantum Dots with Uniform Particle Size and Bright Tunable Fluorescence in the NIR-II Window.

Ag2 S quantum dots (QDs) are well-known near-infrared fluorophores and have attracted great interest in biomedical labeling and imaging in the past years. However, their photoluminescence efficiency is hard to compete with Cd-, Pb-based QDs. The high Ag+ mobility in Ag2 S crystal, which causes plenty of cation deficiency and crystal defects, may be responsible mainly for the low photoluminescence quantum yield (PLQY) of Ag2 S QDs. Herein, a cation-doping strategy is presented via introducing a certain dosage of transition metal Pb2+ ions into Ag2 S nanocrystals to mitigate this intrinsic shortcoming. The Pb-doped Ag2 S QDs (designated as Pb:Ag2 S QDs) present a renovated crystal structure and significantly enhanced optical performance. Moreover, by simply adjusting the levels of Pb doping in the doped nanocrystals, Pb:Ag2 S QDs with bright emission (PLQY up to 30.2%) from 975 to 1242 nm can be prepared without altering the ultrasmall particle size (≈2.7-2.8 nm). Evidently, this cation-doping strategy facilitates both the renovation of crystal structure of Ag2 S QDs and modulation of their optical properties.

The epidemiology of traumatic brain injuries in the fastest-paced city in China: a retrospective study.

Introduction: Traumatic brain injury (TBI) seriously affects the quality of human health and the prognosis of the patient, but the epidemiological characteristics of TBI can vary among populations. Numerous changes have occurred in the epidemiological characteristics of individuals with TBI in the fast-paced city of Shenzhen, China. However, little is known about these characteristics. This study aimed to investigate the changes in TBI epidemiology, help clinicians improve medical treatment. Methods: In this retrospective cross-sectional analysis, we collected the data of 4,229 patients with TBI admitted to 20 hospitals in Shenzhen in 2017. We collected data on age, gender, cause and severity of the injury, eventual diagnosis, time from injury to admission in a neurosurgery department, and patient outcomes. Two neurosurgeons simultaneously collected the data. We compared these results with a similar study conducted in Shenzhen during the period from 1994 to 2003 to clarify and explain the changes in the epidemiological characteristics of TBI. Results: The majority of respondents were men [2,830 (66.9%)]. The mean age was 32.5 ± 21.4 years. The youngest patient was less than 1 year old, and the oldest patient was 101 years old. A total of 3,947 (93.3%) patients had a favorable outcome, 219 (5.2%) had an unfavorable outcome, and 63 (1.5%) died. The predominant external cause was falls (1,779 [42.1%]); this was the most common cause of TBI in children and older adults. Riders of electric bicycles (423 [29.0%]) were the most vulnerable to traffic accident-related injuries. Time greater than 50 h from injury to admission to a neurosurgical department had a significant effect on prognosis (p < 0.001). Conclusion: The epidemiological characteristics of TBI have changed significantly over the past 20 years. Falls, rather than traffic accidents, were the most common cause of TBI. Further research is needed to devise solutions to decrease the incidence of falls and improve the outcomes of TBI.

Serum Levels of MMP-8 and MMP-9 as Markers in Chronic Subdural Hematoma.

Chronic subdural hematoma (CSDH) is a common neurological disease that involves the collection of blood products in the subdural space. The progression of CSDH is an angiogenic and inflammatory process, but the multifactorial mechanisms underlying CSDH are still not fully understood. We aimed to identify one or more factors that may play an important role in the development of CSDH. We enrolled 83 patients with CSDH, including 17 postoperative patients, and analyzed 20 markers in the hematoma fluid and peripheral blood of each patient. Overall differential gene expression was examined to identify the representative markers. The concentration of MMP-8 was significantly lower in the postoperative group than in the preoperative group. The concentration of MMP-9 was significantly higher in the postoperative group than in the preoperative group. These findings indicate that MMP-8 and MMP-9 may play important roles in the pathophysiology of CSDH. Understanding the pathways associated with CSDH may provide insights for improving disease outcomes.

Long-standing overt ventriculomegaly in adulthood with primary presentation of psychiatric disturbance: A case report.

RATIONALE: Hydrocephalus is a common disease in neurosurgery. The typical symptoms of hydrocephalus include urinary incontinence, gait instability, and cognitive decline. Irritability rarely occurs in patients with hydrocephalus. Irritability rarely occurs in patients with hydrocephalus, especially in long-standing overt ventriculomegaly of adulthood (LOVA). PATIENT CONCERNS: A 30-year-old female was admitted to our hospital because of mental retardation and unstable gait for more than 15 years. She had undergone ventriculoperitoneal shunt 15 years prior due to ventriculomegaly and related symptoms. However, the shunt catheter was removed shortly after surgery because of blockage, with no further postoperative treatment. DIAGNOSIS: The patient was diagnosed with long-standing overt ventriculomegaly according to her head circumference and clinical symptoms, including adult hydrocephalus development, overt triventriculomegaly and absence of a secondary cause for aqueductal stenosis in adulthood. INTERVENTIONS: After considerable discussion, she underwent ventriculoperitoneal shunt placement and showed dramatic and sustained improvement. OUTCOMES: The patient has been followed at 3-month intervals for over 2 years since discharge, and both the patient and family have reported a significant change in their daily life. She was able to live independently and control her emotions. Slight epilepsy was noted approximately 5 months after surgery but recovered 2 months later. LESSONS: It is difficult to decide whether to treat LOVA when the in patients whose symptoms are not significant. We believe that early diagnosis and positive treatment can help improve outcomes and would recommend ventriculoperitoneal (VP) shunting in patients with LOVA.

Preparation of Monodisperse Hydrophilic Quantum Dots with Amphiphilic Polymers.

Monodisperse hydrophilic quantum dots (QDs) are promising labeling materials for biomedical applications. However, the controllable preparation of monodisperse hydrophilic QDs with amphiphilic polymers remains a challenge. Herein, the molecular structures of amphiphilic polymers assembled on different-sized QDs are investigated. Both the experimental results and the molecular dynamics (MD) calculation suggest that the grafting ratio of amphiphilic polymers assembled on QDs increases as the size of QDs increases. Thus, the controllable preparation of different-sized monodisperse hydrophilic QDs can be achieved by simply varying the grafting ratio of amphiphilic molecules and applied in the simultaneous labeling of three tumor biomarkers.

A highly reactive chalcogenide precursor for the synthesis of metal chalcogenide quantum dots.

Metal chalcogenide semiconductor nanocrystals (NCs) are ideal inorganic materials for solar cells and biomedical labeling. In consideration of the hazard and instability of alkylphosphines, the phosphine-free synthetic route has become one of the most important trends in synthesizing selenide QDs. Here we report a novel phase transfer strategy to prepare phosphine-free chalcogenide precursors. The anions in aqueous solution were transferred to toluene via electrostatic interactions between the anions and didodecyldimethylammonium bromide (DDAB). The obtained chalcogenide precursors show high reactivity with metal ions in the organic phase and could be applied to the low-temperature synthesis of various metal chalcogenide NCs based on a simple reaction between metal ions (e.g. Ag(+), Pb(2+), Cd(2+)) and chalcogenide anions (e.g. S(2-)) in toluene. In addition to chalcogenide anions, other anions such as BH4(-) ions and AuCl4(-) ions can also be transferred to the organic phase for synthesizing noble metal NCs (such as Ag and Au NCs).

Total glucosides of peony attenuates experimental autoimmune encephalomyelitis in C57BL/6 mice.

Total glucosides of peony (TGP), an active compound extracted from the roots of Paeonia lactiflora Pall, has wide pharmacological effects on nervous system. Here we examined the effects of TGP on experimental autoimmune encephalomyelitis (EAE), an established model of multiple sclerosis (MS). The results showed that TGP can reduce the severity and progression of EAE in C57 BL/6 mice. In addition, TGP also down-regulated the Th1/Th17 inflammatory response and prevented the reduced expression of brain-derived neurotrophic factor and 2',3'-cyclic nucleotide 3'-phosphodiesterase of EAE. These findings suggest that TGP could be a potential therapeutic agent for MS.

Ag2Se quantum dots with tunable emission in the second near-infrared window.

Quantum dots (QDs) with fluorescence in the second near-infrared window (NIR-II, 1000-1400 nm) are ideal fluorophores for in vivo imaging of deep tissue with high signal-to-noise ratios. Ag2Se (bulk band gap 0.15 eV) is a promising candidate for preparing NIR-II QDs. By using 1-octanethiol as ligand to effectively balance the nucleation and growth, tuning the fluorescence of Ag2Se QDs was successfully realized in the NIR-II window ranged from 1080 to 1330 nm. The prepared Ag2Se QDs can be conveniently transferred to the aqueous phase by ligand exchange, showing great potential for multicolor NIR-II fluorescence imaging in vivo.

[Artemin and GFRalpha3 expressions and their relevance to perineural invasiveness and metastasis of pancreatic carcinoma].

OBJECTIVE: To investigate the association of artemin and GFRalpha3 expressions with perineural invasion and metastasis of pancreatic carcinoma. METHODS: Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry were used to detect the expression of artemin and GFRalpha3 in pancreatic carcinoma tissues, adjacent tissues and normal pancreas tissues, and the relevance of artemin and GFRalpha3 expressions to the perineural invasion and metastasis of pancreatic carcinoma were analyzed. RESULTS: The positivity rates of artemin and GFRalpha3 expressions were 72.09% and 67.44% in pancreatic carcinoma, respectively, significantly higher than those in the adjacent tissue (18.19% and 22.73%). The positivity rates of artemin and GFRalpha3 expressions were significantly higher in patients with perineural invasion than in those without perineural invasion (chi(2)=11.11 and 11.78, respectively, P<0.01). Significantly higher expression of artemin mRNA was noted in pancreatic carcinoma (0.741-/+0.014) than in the normal pancreas tissue (0.101-/+0.031, P<0.05), and patients with perineural invasion showed significantly higher positivity rates of artemin mRNA expression (0.843-/+0.012) than those without perineural invasion (0.512-/+0.017, P<0.05). CONCLUSION: Artemin and GFRalpha3 expressions may play an important role in perineural invasion of pancreatic carcinoma and can be used a useful indicators for evaluating the biological behavior of pancreatic carcinomas.