3D spiral channels combined with flexible micro-sieve for high-throughput rare tumor cell enrichment and assay from clinical pleural effusion samples

The sieving and enrichment of rare tumor cells from large-volume pleural effusion(PE)samples is a promising technique for cell-based lung tumor diagnosis and drug tests,which features high throughput and recovery,purification,as well as viability rates of rare target cells as the prerequisites for high sensitivity,specificity,and accuracy of tumor cell analysis.In this paper,we propose a three-dimensional(3 D)sieving method for rare tumor cell enrichment,which effectively eliminates the"dead zones"in traditional two-dimensional(2 D)cell filters with a dimension-raising strategy to satisfy the requirements mentioned above.The prototype device was combined with a funnel-shaped holder,a flexible micropore membrane in the middle,and a3 D spiral fluid channel covered on the membrane as a three-layer ice-creaming cone composite structure.Driven by gravity alone,the device performed as follows:(1)20-fold throughput compared with the 2 D commercial planee hich was up to 20 mL/min for a threefold dilution of whole blood sample;(2)high recovery rates of 84.5%±21%,86%±25%,83%±14%for 100,1000,and 10000 cells/mL,respectively,in 30 mL phosphate buffer saline(PBS)sample,and a 100%positive detection rate in the case of≤5 A549 cells in 1 mL PBS;(3)a typical purification rate of 85.5%±9.1%;and(4)a viability rate of>93%.In the demonstration application,this device effectively enriched rare target cells from large volumes(>25 mL)of clinical pleural effusions.The following results indicated that tumor cells were easy-to-discover in the enriched PE samples,and the proliferation capability of purified cells was(>4.6 times)significantly stronger than that of unprocessed cells in the subsequent 6-day culture.The above evaluation indicates that the proposed easily reproducible method for the effective execution of rare cell enrichments and assays is expected to become a practical technique for clinical cell-based tumor diagnosis.

SERS devices with "hedgehog-like" nanosphere arrays for detection of trace pesticides

The development of surface-enhanced Raman scattering(SERS)devices for detection of trace pesticides has attracted more and more attention.In this work,a large-area self-assembly ap-proach assisted with reactive ion etching(RIE)is proposed for preparing SERS devices consisting of Ag-covered"hedgehog-like"nanosphere arrays(Ag/HLNAs).Such a SERS device has an enhancement factor of 2.79×107,a limit of detection(LOD)up to 10-12 M for Rhodamine 6G(R6G)analytes,and a relative standard deviation(RSD)smaller than 10%,demonstrating high uniformity.Besides,for pesticide detections,the device achieves an LOD of 10-s M for thiram molecules.It indicates that the proposed SERS device has a promising opportunity in detecting toxic organic pesticides.

A direct Z-scheme Bi_(2)WO_(6)/La_(2)Ti_(2)O_(7) photocatalyst for selective reduction of CO_(2) to CO

Simulating photosynthesis to convert CO_(2)into valuable chemicals is an effective strategy to achieve sustainable carbon recycles,and the high conversion efficiency and selectivity of photocatalytic conversion CO_(2)to specific chemicals are the key challenges.Herein,a direct Z-scheme Bi_(2)WO_(6)/La_(2)Ti_(2)O_(7)photocatalyst is successfully syn-thesized by electrostatic self-assembly method.The selectivity of CO_(2)reduction to CO is improved from 74%of La_(2)Ti_(2)O_(7)to nearly 100%,and the CO yield is 7.5 times that of individual La_(2)Ti_(2)O_(7).The improvement of the photocatalytic performance is attributed to the formation of Z-scheme heterojunction between Bi_(2)WO_(6)and La_(2)Ti_(2)O_(7),which facilitates the separation and transfer of photogenerated carriers.This work provides a new insight for the construction of efficient photocatalyst for selective reduction of CO_(2)to CO.

piRT-IFC:Physics-informed real-time impedance flow cytometry for the characterization of cellular intrinsic electrical properties

Real-time transformation was important for the practical implementation of impedance flow cytometry.The major obstacle was the time-consuming step of translating raw data to cellular intrinsic electrical properties(e.g.,specific membrane capacitance C_(sm) and cytoplasm conductivityσ_(cyto)).Although optimization strategies such as neural network-aided strategies were recently reported to provide an impressive boost to the translation process,simultaneously achieving high speed,accuracy,and generalization capability is still challenging.To this end,we proposed a fast parallel physical fitting solver that could characterize single cells’C_(sm)andσ_(cyto)within 0.62 ms/cell without any data preacquisition or pretraining requirements.We achieved the 27000-fold acceleration without loss of accuracy compared with the traditional solver.Based on the solver,we implemented physics-informed real-time impedance flow cytometry(piRT-IFC),which was able to characterize up to 100,902 cells’C_(sm) andσ_(cyto)within 50 min in a real-time manner.Compared to the fully connected neural network(FCNN)predictor,the proposed real-time solver showed comparable processing speed but higher accuracy.Furthermore,we used a neutrophil degranulation cell model to represent tasks to test unfamiliar samples without data for pretraining.After being treated with cytochalasin B and N-Formyl-Met-Leu-Phe,HL-60 cells underwent dynamic degranulation processes,and we characterized cell’s C_(sm)andσ_(cyto)using piRT-IFC.Compared to the results from our solver,accuracy loss was observed in the results predicted by the FCNN,revealing the advantages of high speed,accuracy,and generalizability of the proposed piRT-IFC.

From the teapot effect to tap-triggered self-wetting: a 3D self-driving sieve for whole blood filtration

Achieving passive microparticle filtration with micropore membranes is challenging due to the capillary pinning effect of the membranes.Inspired by the teapot effect that occurs when liquid(tea)is poured from a teapot spout,we proposed a tap-triggered self-wetting strategy and utilized the method with a 3D sieve to flter rare cells.First,a 3D-printed polymer tap-trigger microstructure was implemented.As a result,the 3μm micropore membrane gating threshold(the pressure needed to open the micropores)was lowered from above 3000 to 80 Pa by the tap-trigger microstructure that facilated the liquid leakage and spreading to self-wet more membrane area in a positive feedback loop.Then,we implemented a 3D cone-shaped cell sieve with tap-trigger microstructures.Driven by gravity,the sieve performed at a high throughput above 20 mL/min(DPBS),while the micropore size and porosity were 3μm and 14.1%,respectively.We further filtered leukocytes from whole blood samples with the proposed new 3D sieve,and the method was compared with the traditional method of leukocyte isolation by chemically removing red blood cells.The device exhibited comparable leukocyte purity but a higher platelet removal rate and lower leukocyte simulation level,facilitating downstream single-cell analysis.The key results indicated that the tap-triggered self-wetting strategy could significantly improve the performance of passive microparticle filtration.

基于CiteSpace的我国银行业管理会计研究评述与展望

本文利用文献计量和可视化分析方法对通过CNKI数据库检索出的1991~2021年1004篇银行业管理会计研究文献进行了统计分析。研究发现,我国银行业管理会计研究历程可划分为酿期、探索期、观察期、爆发期四个阶段,发文量整体呈波动上升趋势,相关研究在2019年达到了高峰,但发文作者及发文机构均未形成核心集群。本文首先对关键词前九大聚类进行了分析,其次阐述了热点形成的原因并加以讨论,最后根据近五年的关键词时间区图,对我国银行业管理会计未来研究的趋势进行了分析预测。

Ion flux dropout observed near dipolarization front

An ion flux dropout near the dipolarization front(DF) at around XGSM=-11 REin the Earth's plasma sheet was observed by Time History of Events and Macroscale Interaction during substorms(THEMIS) on March31, 2009. The ion differential energy fluxes at energies from 450 e V to 150 ke V measured by the ESA and SST instruments from THC began to decrease about 2 s before the detection of the DF and reached a local minimum 6 s later. Then, the ion fluxes gradually increased to form a dropout around the DF. The spatial extent of the dropout was about 4,000 km. For energies above 20 ke V, the ion fluxes after the dropout are greater than those before it,contrary to the fluxes at energies below 20 ke V. The associated ion density variation indicates that the ion flux dropout coincides with the ion density dropout. Taking advantage of multipoint observations, THD, THC, and THE detected the same DF consecutively. Only THC detected an obvious ion flux dropout; THD observed an indistinct one about 2 s before THC; no high-energy(E [ 30 ke V) ion flux dropout was observed by THE. Our study suggests that the ion flux dropout may evolve withthe earthward-propagating DF, and its properties can depend on locations relative to the DF.