Dynamic Structural Fluxionality in a Planar Tetracoordinate Carbon Cluster Stabilized by Boron Ligands.

The design of boron-based molecular rotors stems from boron-carbon binary clusters containing multiple planar hypercoordinate carbons (phCs, such as C2B8). However, the design of boron-coordinated phCs is challenging due to boron's tendency to occupy hypercoordinate centers more than carbon. Although this challenge has been addressed, the designed clusters of interest have not exhibited dynamic fluxionality similar to that of the initial C2B8. To address this issue, we report a σ/π doubly aromatic CB2H5 + cluster, the first global minimum containing a boron-coordinated planar tetracoordinate carbon atom with dynamic fluxionality. Dynamics simulations show that two ligand H atoms exhibit alternate rotation, resulting in an intriguing dynamic fluxionality in this cluster. Electronic structure analysis reveals the flexible bonding positions of the ligand H atoms because they do not participate in π delocalized bonding nor bond to any other non-carbon atom, highlighting this rotational fluxionality. Unprecedentedly, the fluxional process involves not only the usual conversion of the number of bonding atoms, but also the type of bonding (3c π bonds ↔4c σ bonds), which is an uncommon fluxional mechanism. The cluster represents an effort to apply phC species to molecular machines.

Approaching Standardization: Mechanical Material Testing of Macroscopic Two-Photon Polymerized Specimens.

Two-photon polymerization (2PP) is becoming increasingly established as additive manufacturing technology for microfabrication due to its high-resolution and the feasibility of generating complex parts. Until now, the high resolution of 2PP is also its bottleneck, as it limited throughput and therefore restricted the application to the production of microparts. Thus, mechanical properties of 2PP materials can only be characterized using nonstandardized specialized microtesting methods. Due to recent advances in 2PP technology, it is now possible to produce parts in the size of several millimeters to even centimeters, finally permitting the fabrication of macrosized testing specimens. Besides suitable hardware systems, 2PP materials exhibiting favorable mechanical properties that allow printing of up-scaled parts are strongly demanded. In this work, the up-scalability of three different photopolymers is investigated using a high-throughput 2PP system and low numerical aperture optics. Testing specimens in the cm-range are produced and tested with common or even standardized material testing methods available in conventionally equipped polymer testing labs. Examples of the characterization of mechanical, thermo-mechanical, and fracture properties of 2PP processed materials are shown. Additionally, aspects such as postprocessing and aging are investigated. This lays a foundation for future expansion of the 2PP technology to broader industrial application.

CBe2 H5 - : Unprecedented 2σ/2π Double Aromaticity and Dynamic Structural Fluxionality in a Planar Tetracoordinate Carbon Cluster.

A 14-electron ternary anionic CBe2 H5 - cluster containing a planar tetracoordinate carbon (ptC) atom is designed herein. Remarkably, it can be stabilized by only two beryllium atoms with both π-acceptor/σ-donor properties and two hydrogen atoms, which means that the conversion from planar methane (transition state) to ptC species (global minimum) requires the substitution of only two hydrogen atoms. Moreover, two ligand H atoms exhibit alternate rotation, giving rise to interesting dynamic fluxionality in this cluster. The electronic structure analysis reveals the flexible bonding positions of ligand H atoms due to C-H localized bonds, highlighting the rotational fluxionality in the cluster, and two CBe2 3c-2e delocalized bonds endow its rare 2σ/2π double aromaticity. Unprecedentedly, the fluxional process exhibits a conversion in the type of bonding (σ bond↔π bond), which is an uncommon fluxional mechanism. The cluster can be seen as an attempt to apply planar hypercoordinate carbon species to molecular motors.

Boron-based Pd3B26 alloy cluster as a nanoscale antifriction bearing system: tubular core-shell structure, double π/σ aromaticity, and dynamic structural fluxionality.

Boron-based nanoclusters show unique geometric structures, nonclassical chemical bonding, and dynamic structural fluxionality. We report here on the theoretical prediction of a binary Pd3B26 cluster, which is composed of a triangular Pd3 core and a tubular double-ring B26 unit in a coaxial fashion, as identified through global structural searches and electronic structure calculations. Molecular dynamics simulations indicate that in the core-shell alloy cluster, the B26 double-ring unit can rotate freely around its Pd3 core at room temperature and beyond. The intramolecular rotation is virtually barrier free, thus giving rise to an antifriction bearing system (or ball bearing) at the nanoscale. The dimension of the dynamic system is only 0.66 nm. Chemical bonding analysis reveals that Pd3B26 cluster possesses double 14π/14σ aromaticity, following the (4n + 2) Hückel rule. Among 54 pairs of valence electrons in the cluster, the overwhelming majority are spatially isolated from each other and situated on either the B26 tube or the Pd3 core. Only one pair of electrons are primarily responsible for chemical bonding between the tube and the core, which greatly weaken the bonding within the Pd3 core and offers structural flexibility. This is a key mechanism that effectively diminishes the intramolecular rotation barrier and facilitates dynamic structural fluxionality of the system. The current work enriches the field of nanorotors and nanomachines.

Planar Hexacoordinate Beryllium: Covalent Bonding Between s-block Metals.

Achieving a planar hypercoordinate arrangement of s-block metals through covalent bonding with ligands is challenging due to the strong ionicity involved. Herein, we report the first case of a neutral binary global minimum containing a planar hexacoordinate beryllium atom. The central Be atom is coordinated by six active Be atoms, the latter in turn are enclosed by an equal number of more electronegative chlorine atoms in the periphery, forming a star-like phBe cluster (Be©Be6 Cl6 ). Importantly, the cluster exhibits dynamically stabilized stemming geometrically from the appropriate matching of metal-ligand size and electronically from adherence to the octet rule as well as possessing a 6σ/2π double aromaticity. Remarkably, energy decomposition analysis-natural orbitals for chemical valence (EDA-NOCV) analysis reveals a significant covalent interaction between the ligand and the central metal beryllium atoms, a fact further supported by a large Wiberg bond index. This cluster is a promising synthetic as its excellent electronic, dynamic and thermodynamic stability.

The benefits of neoadjuvant therapy for patients with resectable pancreatic cancer: an updated systematic review and meta-analysis.

Neoadjuvant therapy (NAT) was effective in improving overall survival (OS) of borderline resectable pancreatic cancer. However, its application in resectable pancreatic cancer remains controversial. This study aimed to determine whether NAT has a greater advantage over conventional upfront surgery (US) in terms of resection rate, R0 resection rate, positive lymph node rate, and OS. We identified articles before October 7, 2022, by searching four electronic databases. The studies included in the meta-analysis all met the inclusion and exclusion criteria. The Newcastle-Ottawa scale was used to evaluate the quality of the articles. OS, DFS, resection rate, R0 resection rate and positive lymph nodes rate were extracted. Odds ratio (OR), hazard ratio (HR) and 95% confidence intervals (CI) were calculated, and sensitivity analysis and publication bias were used to assess the sources of heterogeneity. In total, 24 studies, involving 1384 (35.66%) patients assigned to NAT and 2497 (64.43%) patients assigned to US, were included in the analysis. NAT could effectively prolong OS (HR 0.73, 95% CI 0.65-0.82, P < 0.001) and DFS (HR 0.72, 95% CI 0.62-0.84, P < 0.001). Subgroup analysis results of 6 randomized controlled trials (RCTs) also showed that RPC patients could benefit from NAT in the long term (HR 0.72, 95% CI 0.58-0.90, P = 0.003). NAT decreased resection rate (OR 0.43, 95% CI 0.33-0.55, P < 0.001), but was associated with increased R0 resection rate (OR 2.05, 95% CI 1.47-2.88, P < 0.001) and decreased positive lymph node rate (OR 0.38, 95% CI 0.27-0.52, P < 0.001). Although the application of NAT increases the risk of patients not being able to undergo surgical resection, it can prolong the OS and delay tumor progression in RPC. Therefore, we still expect larger and higher-quality RCTs to confirm the effectiveness of NAT.

Chemical Bonding and Dynamic Structural Fluxionality of a Boron-Based Na5B7 Sandwich Cluster.

Doping alkali metals into boron clusters can effectively compensate for the intrinsic electron deficiency of boron and lead to interesting boron-based binary clusters, owing to the small electronegativity of the former elements. We report on the computational design of a three-layered sandwich cluster, Na5B7, on the basis of global-minimum (GM) searches and electronic structure calculations. It is shown that the Na5B7 cluster can be described as a charge-transfer complex: [Na4]2+[B7]3-[Na]+. In this sandwich cluster, the [B7]3- core assumes a molecular wheel in shape and features in-plane hexagonal coordination. The magic 6π/6σ double aromaticity underlies the stability of the [B7]3- molecular wheel, following the (4n + 2) Hückel rule. The tetrahedral Na4 ligand in the sandwich has a [Na4]2+ charge-state, which is the simplest example of three-dimensional aromaticity, spherical aromaticity, or superatom. Its 2σ electron counting renders σ aromaticity for the ligand. Overall, the sandwich cluster has three-fold 6π/6σ/2σ aromaticity. Molecular dynamics simulation shows that the sandwich cluster is dynamically fluxional even at room temperature, with a negligible energy barrier for intramolecular twisting between the B7 wheel and the Na4 ligand. The Na5B7 cluster offers a new example for dynamic structural fluxionality in molecular systems.

The dodeca-coordinated La©B8C4 +/0/- molecular wheels: conflicting aromaticity versus double aromaticity.

The transition-metal centered boron molecular wheels have attracted the attention of chemists. The highest deca-coordination number for central metal atoms was observed in D 10h Ta©B10 - and Nb©B10 - molecular wheels. Here, we report a theoretical study of La©B8C4 q (q = +1, 0, -1) clusters with the dodeca-coordinated La atom. The La©B8C4 q clusters adopt fascinating molecular wheel structures, showing a La atom enclosed by a perfect B8C4 monocyclic ring. The cationic La©B8C4 + cluster has a C 4v symmetry with the distinctly out-of-plane distortion of the La atom (0.70 Å), which is gradually flattened by the sequential reduction reaction. The distortion of the La atom from the plane in the neutral La©B8C4 cluster decreases to 0.46 Å. The La©B8C4 - species turns out to be perfectly planar. Chemical bonding analyses indicate that the neutral La©B8C4 and anionic La©B8C4 - possess 10σ and 9π/10π double aromaticity, respectively, obeying the principle of double aromaticity. However, the cationic La©B8C4 + has 10σ and 8π conflicting aromaticity, representing a counterexample in planar hyper-coordinated molecular wheels. The dodeca-coordination number in La©B8C4 q (q = +1, 0, -1) clusters is unprecedented, which provides a new idea and concept for searching planar hyper-coordinated systems.

Corrigendum to "Development of methods for detecting the fate of mesenchymal stem cells regulated by bone bioactive materials" [Bioact. Mater. 6(3) (2021) 613-626].

[This corrects the article DOI: 10.1016/j.bioactmat.2020.08.035.].

Be3B11- cluster: a dynamically fluxional beryllo-borospherene.

The beryllium-doped Be3B11- cluster has two nearly isoenergetic isomers, adopting the smallest trihedral spherical geometries with a boron single-chain skeleton. The B11 skeleton in the global minimum (C2v, 1A1) comprises three conjoined boron rings (one B8/two B7) on the waist, sharing two B3 equilateral triangles at the top and bottom, respectively. However, the local minimum (Cs, 1A') has one deformed B4 pyramid at the top. The drastic structural transformation of B11 skeletons from perfectly planar B11 clusters mainly profited from robust electrostatic interaction between Be atoms and B11 skeletons. The dynamic simulations suggest that two species can interconvert via a novel mechanism, that is "triangle-pyramid-triangle", which facilitates the free migration of boron atoms in the B11 skeleton, thereby showing the fascinating dynamic fluxionality. The chemical bonding analyses reveal that the B11 skeleton is covered by two types of delocalized π bonds in an orthogonal direction, which leads to its spherical aromaticity.

Targeted next-generation sequencing for pulmonary infection diagnosis in patients unsuitable for bronchoalveolar lavage.

Background: Targeted next-generation sequencing (tNGS) has emerged as a rapid diagnostic technology for identifying a wide spectrum of pathogens responsible for pulmonary infections. Methods: Sputum samples were collected from patients unable or unwilling to undergo bronchoalveolar lavage. These samples underwent tNGS analysis to diagnose pulmonary infections. Retrospective analysis was performed on clinical data, and the clinical efficacy of tNGS was compared to conventional microbiological tests (CMTs). Results: This study included 209 pediatric and adult patients with confirmed pulmonary infections. tNGS detected 45 potential pathogens, whereas CMTs identified 23 pathogens. The overall microbial detection rate significantly differed between tNGS and CMTs (96.7% vs. 36.8%, p < 0.001). Among the 76 patients with concordant positive results from tNGS and CMTs, 86.8% (66/76) exhibited full or partial agreement. For highly pathogenic and rare/noncolonized microorganisms, tNGS, combined with comprehensive clinical review, directly guided pathogenic diagnosis and antibiotic treatment in 21 patients. This included infections caused by Mycobacterium tuberculosis complex, certain atypical pathogens, Aspergillus, and nontuberculous Mycobacteria. Among the enrolled population, 38.8% (81/209) of patients adjusted their treatment based on tNGS results. Furthermore, tNGS findings unveiled age-specific heterogeneity in pathogen distribution between children and adults. Conclusion: CMTs often fall short in meeting the diagnostic needs of pulmonary infections. This study highlights how tNGS of sputum samples from patients who cannot or will not undergo bronchoalveolar lavage yield valuable insights into potential pathogens, thereby enhancing the diagnosis of pulmonary infections in specific cases.

Y©B8C4 cluster: a boron-carbon molecular wheel with dodeca-coordination number in plane.

Computational evidence is reported for the largest planar molecular wheel of the Y©B8C4 cluster, featuring an yttrium atom enclosed by a highly symmetric B8C4 ring. The B8C4 ring is viable in the -(BCB)4- form with double 9π/10σ aromaticity. The centered yttrium atom is dodeca-coordinated with the peripheral B8C4 ring, which sets a record coordination number for a planar structure in chemistry heretofore.

Early detection of circulating tumor DNA and successful treatment with osimertinib in thr790met-positive leptomeningeal metastatic lung cancer: A case report.

BACKGROUND: Patients diagnosed with non-small-cell lung cancer with activated epidermal growth factor receptor mutations are more likely to develop leptomeningeal (LM) metastasis than other types of lung cancers and have a poor prognosis. Early diagnosis and effective treatment of leptomeningeal carcinoma can improve the prognosis. CASE SUMMARY: A 55-year-old female with a progressive headache and vomiting for one month was admitted to Peking University First Hospital. She was diagnosed with lung adenocarcinoma with osseous metastasis 10 months prior to admittance. epidermal growth factor receptor (EGFR) mutation was detected by genomic examination, so she was first treated with gefitinib for 10 months before acquiring resistance. Cell-free cerebrospinal fluid (CSF) circulating tumor DNA detection by next-generation sequencing was conducted and indicated the EGFR-Thr790Met mutation, while biopsy and cytology from the patient's CSF and the first enhanced cranial magnetic resonance imaging (MRI) showed no positive findings. A month later, the enhanced MRI showed linear leptomeningeal enhancement, and the cytology and biochemical examination in CSF remained negative. Therefore, osimertinib (80 mg/d) was initiated as a second-line treatment, resulting in a good response within a month. CONCLUSION: This report suggests clinical benefit of osimertinib in LM patients with positive detection of the EGFR-Thr790Met mutation in CSF and proposes that the positive findings of CSF circulating tumor DNA as a liquid biopsy technology based on the detection of cancer-associated gene mutations may appear earlier than the imaging and CSF findings and may thus be helpful for therapy. Moreover, the routine screening of chest CT with the novel coronavirus may provide unexpected benefits.

Maternal obesity alters methylation level of cytosine in CpG island for epigenetic inheritance in fetal umbilical cord blood.

BACKGROUND: Over the past few decades, global maternal obesity prevalence has rapidly increased. This condition may induce long-lasting pathophysiological effects on either fetal or infant health that could be attributable to unknown unique changes in the umbilical blood composition. METHODS: A total of 34 overweight/obese and 32 normal-weight pregnant women were recruited. Fifteen umbilical blood samples including 8 overweight/obese subjects and 7 normal weight women were sequenced using Targeted Bisulfite Sequencing technology to detect the average methylation level of cytosine and identify the differentially methylated region (DMR). GO and KEGG analyses were then employed to perform pathway enrichment analysis of DMR-related genes and promoters. Moreover, the mRNA levels of methylation-related genes histone deacetylases (HDACs) and DNA methyltransferases (DNMTs) were characterized in the samples obtained from these two groups. RESULTS: Average methylated cytosine levels in both the CpG islands (CGI) and promoter significantly decreased in overweight/obese groups. A total of 1669 DMRs exhibited differences in their DNA methylation status between the overweight/obese and control groups. GO and KEGG analyses revealed that DMR-related genes and promoters were enriched in the metabolism, cancer and cardiomyopathy signaling pathways. Furthermore, the HDACs and DNMTs mRNA levels trended to decline in overweight/obese groups. CONCLUSIONS: Decreased methylated cytosine levels in overweight/obese women induce the gene expression activity at a higher level than in the control group. DMRs between these two groups in the fetal blood may contribute to the changes in gene transcription that underlie the increased risk of metabolic disorders, cancers and cardiomyopathy in their offspring.

The unique sandwich K6Be2B6H6 cluster with a real borozene B6H6 core.

Theoretical evidence is reported for a boron-based K6Be2B6H6 sandwich cluster, showing a perfectly D 6h B6H6 ring, being capped by two tetrahedral K3Be ligands. Due to the comfortable charge transfer, the sandwich is viable in [K3Be]3+[B6H6]6-[BeK3]3+ ionic complex in nature. The [B6H6]6- core with 6π aromaticity vividly imitates the benzene (C6H6), occurring as a real borozene. In contrast, the tetrahedral [K3Be]3+ ligand is 2σ three-dimensional aromatic, acting as the simple superatom. Thus, this complex possesses a collectively three-fold 2σ/6π/2σ aromaticity. The interlaminar interaction is governed by the robust electrostatic attraction. The unique chemical bonding gives rise to interesting dynamic fluxionality.

Primary central nervous system ALK-negative anaplastic large cell lymphoma: a case report and literature review.

Primary central nervous system anaplastic lymphoma kinase (ALK)-negative anaplastic large cell lymphoma (ALCL) is an extremely rare type of primary central nervous system lymphoma (PCNSL). There are only nine cases reported in the literature to date, most of which have an overall survival time of no more than 8 months. Herein, we report such a rare case who has a good outcome with the longest survival time and perform a review of the literature. A 19-year-old male patient was admitted to the hospital complaining of dizziness. CT and MRI imaging showed a heterogeneous enhanced lesion in the left parieto-occipital lobe and the leptomeninges of the occipital lobe and the cerebellum. The lesion was resected and confirmed to be ALK-negative ALCL by pathological examination. Then, the patient received 10 cycles of chemotherapy with high-dose methotrexate (HD-MTX) and whole-brain radiotherapy. The patient recovered well and was regularly followed up. He was free of symptoms without recurrence on imaging examination 3 years later. ALCL is a rare type of PCNSL. HD-MTX combined with radiation is an effective therapeutic approach. However, further prospective studies with a large number of patients are needed to identify the biological characteristics of this rare type of PCNSL.

Staged Endovascular Treatment for Symptomatic Occlusion Originating From the Intracranial Vertebral Arteries in the Early Non-acute Stage.

Background: The ideal treatment for patients who survive from acute vertebrobasilar artery occlusion but develop aggressive ischemic events despite maximal medical therapy in the early non-acute stage is unknown. This paper reports the technical feasibility and outcome of staged endovascular treatment in a series of such patients with symptomatic intracranial vertebral artery occlusion. Methods: Ten consecutive patients who presented with aggressive ischemic events in the early non-acute stage of intracranial vertebral artery occlusion from Jan 2015 to Nov 2020 were retrospectively reviewed. Among them, eight male and two female patients with a mean age of 66.7 years developed aggressive ischemic events, and the NIHSS score was elevated by a median of 7 points despite medical therapy. All patients received staged endovascular treatment 4-21 days from onset, at an average of 11 days. The strategy of staged treatment was as follows: first, a microwire was passed through the portion of the occlusion, which was then dilated with balloon inflation to maintain the perfusion above TICI grade 2b. Then, with the use of antiplatelet drugs, the residual intravascular thrombus was gradually eliminated by the continuous perfusion and an activated fibrinolytic system, leaving the residual stenosis. A second stage of angioplasty with stent implantation was subsequently performed if residual stenosis was ≥50%. The NIHSS scores and mRS scores were compared between pre- and post-endovascular treatment groups and in the follow-up period. Results: Technical success was achieved in 9 patients who received staged endovascular treatment (perforation occurred in one patient during the first stage). The NIHSS scores were significantly improved, with a median score 7 points lower on discharge compared with the scores for the most severe status. Favorable outcomes with mRS score ≤ 2 were achieved in 7 and 9 patients at the 3-month follow-up and the latest follow-up, respectively, which was better than the preoperative status. Conclusion: Staged endovascular treatment might be a safe, efficient, and viable option in carefully selected patients with symptomatic intracranial vertebral artery occlusion in the early non-acute stage. However, this needs to be confirmed by further investigation, preferably in a large, controlled setting.

Thirty-Day and One-Year Outcomes of Endovascular Treatments for Severe Atherosclerotic Stenosis of Intracranial ICA: Results From a Single Center.

Background: Endovascular treatment for intracranial atherosclerotic stenosis (ICAS) has been developed. However, the intracranial internal carotid artery (ICA) presents a particular challenge due to the location and tortuous route, and the outcomes of endovascular treatment in patients with stenosis of the intracranial ICA still have not been reported. This article retrospectively investigated the 30-day and 1-year outcomes of tailored endovascular treatment for patients with severe intracranial ICA stenosis from a single center. Methods: Between June 2014 and December 2017, 96 consecutive patients with severe atherosclerotic stenosis (70-99%) of the intracranial ICA were managed with endovascular treatment in Beijing Tiantan Hospital. Three different kinds of treatments [angioplasty with balloon dilatation alone (BD group), balloon-mounted stent (BMS group), and self-expanding stent (SES group)] were performed according to the characteristics of the lesions. The primary endpoints included any stroke or death within 30 days and ipsilateral ischemic stroke afterwards within 1 year. Secondary endpoints included the revascularization success rate (residual stenosis <30%) and the restenosis rate (stenosis ≥ 50%) within 1 year. Results: The 30-day death rate was 0, and the stroke rate of all patients was 7.3% (7/96). The stroke rate was higher in the BD group (15.8%) and SES group (9.8%) than in the BMS group (0%) (p = 0.047). Thirteen (13.5%) patients suffered at least one onset of ischemic stroke in the ipsilateral ICA territory within 1 year, and there was no significant difference among the three groups (p = 0.165). The overall revascularization success rate was 93.8%, and the revascularization success rate was significantly higher in the SES group (100%) than in the BD group (78.9%) (p = 0.006). The restenosis rate of all patients within 12 months was 20.8%, and there was no significant difference among the three groups. Patients with Mori type C target lesions were more likely to suffer stroke within 30 days (25%) and restenosis within 1 year (31.3%). Conclusions: Both the 30-day and 1-year outcomes of tailored endovascular treatments seemed to be acceptable in the treatment of symptomatic atherosclerotic stenosis of the intracranial ICA. However, this needs to be confirmed by further investigation, preferably in large multicenter randomized controlled clinical trials.

Case Report: Multi-Orifices Vertebral Arteriovenous Fistula With Severe Scoliosis in Neurofibromatosis Type 1: Might Be a Congenital Disease With Mesodermal Dysplasia.

Background: Vertebral arteriovenous fistula (AVF) associated with neurofibromatosis type 1 (NF-1) is a rare condition in the previous reports. However, whether vertebral AVF in NF-1 is congenital or NF-1 disease progression hasn't been clarified. Case Description: We reported a 48-year-old male case of vertebral AVF simultaneously combined with thoracic scoliosis and NF-1. Preoperative CT angiography showed the AVF with multiple orifices located on the vessel wall of the vertebral artery, which was proved during the procedure of endovascular treatment. By occluding the parent vertebral artery, the AVF was finally cured. Further whole-exome sequencing identified a novel germline heterozygous point nonsense mutation, c.G397T(p.E133X), in the NF1(NM_000267) gene exon4. Conclusions: From this patient, we speculate that vertebral AVF associated with NF-1 might be a congenital disease as a manifestation of mesodermal dysplasia.

Whether Intracranial Aneurysm Could Be Well Treated by Flow Diversion: A Comprehensive Meta-Analysis of Large-Sample Studies including Anterior and Posterior Circulation.

BACKGROUND: Flow diversion (FD) has become a widely adopted treatment method for intracranial aneurysms in the clinic, but a comprehensive meta-analysis of large-sample studies including anterior and posterior circulation is still lacking. METHODS: The PubMed, Embase, Web of Science, and Cochrane databases were searched between January 1, 2008, and December 1, 2019. A random-effect model was used to calculate the efficacy and safety data as well as 95% confidence intervals (CIs). RESULTS: The pooled sample size of all included studies was 6695 patients; the mean age was 55.5 years old, with a total of 7406 aneurysms. For efficacy, the complete occlusion rate in angiographic follow-up (AFU) at 6 months was 78% (95% CI, 0.77, 0.80), and the AFU rate at 6-12 months was 90% (95% CI, 0.88, 0.92). For safety, the hemorrhagic event rate was 2%, the ischemic event rate was 5%, and the mortality rate was 3%. CONCLUSION: FD is an effective and safe treatment for intracranial aneurysm with high complete occlusion rate and acceptable complication rate.