Rapid Capture Research Articles

Phosphorylated calix[4]arene/balsa wood copolymers for selective uranyl extraction from wastewater and seawater

Hyper-crosslinked polymers are frequently used to recover specific guest molecules due to their high porosities, excellent chemical properties, and structural stability. However, the recovery of powder adsorbents poses a significant challenge in the extraction of uranyl from aqueous solutions, which limits their practical application. A phosphorylated calix[4]arene/balsa wood copolymer (C4-W-P) was successfully synthesized and utilized for the extraction of uranyl from radioactive wastewater and seawater. Compared to previously reported adsorbents, C4-W-P demonstrated rapid uranyl capture kinetics, with adsorption equilibrium achieved within 150 min. The material exhibited a monolayer saturation adsorption capacity of 473.9 mg·g−1 at pH 5. Thermodynamic studies confirmed the spontaneous and endothermic nature of the adsorption process. Furthermore, C4-W-P exhibited exceptional structural stability, with only a 9.7 % reduction in adsorption capacity after six adsorption–desorption cycles. Additionally, C4-W-P demonstrated excellent selectivity in simulated wastewater containing 16 rare metal ions and simulated seawater containing an additional five metal ions. The KdU values were recorded to be 1817.2 and 33,265.3 mL·g−1, respectively, for these conditions. These results demonstrate the high-efficiency uranium removal capabilities of C4-W-P under realistic conditions. The abundant phosphate groups (∼1.69 mmol·g−1) on the material surface were identified as the primary adsorption contributors. Overall, this study provides a promising strategy for uranyl extraction with high selectivity and ease of preparation, contributing to environmental protection and economic development.

Evolution and explosions of metal-enriched supermassive stars: proton rich general relativistic instability supernovae

ABSTRACT The assembly of supermassive black holes poses a challenge primarily because of observed quasars at high redshift, but additionally because of the current lack of observations of intermediate mass black holes. One plausible scenario for creating supermassive black holes is direct collapse triggered by the merger of two gas-rich galaxies. This scenario allows the creation of supermassive stars with solar metallicity. We investigate the behaviour of metal enriched supermassive stars which collapse due to the general relativistic radial instability during hydrogen burning. These stars contain both hydrogen and metals and thus may explode due to the CNO cycle (carbon–nitrogen–oxygen) and the rp process (rapid proton capture). We perform a suite of stellar evolution simulations for a range of masses and metallicities, with and without mass-loss. We evaluate the stability of these supermassive stars by solving the pulsation equation in general relativity. When the stars becomes unstable, we perform 1D general relativistic hydrodynamical simulations coupled to a 153 isotope nuclear network with cooling from neutrino reactions, in order to determine if the stars explode. If the stars do explode, we post process the nucleosynthesis using a 514 isotope network which includes additional proton rich isotopes. These explosions are characterized by enhanced nitrogen and intermediate mass elements ($16\ge \rm {A}\ge 25$), and suppressed light elements ($8\ge \rm {A}\ge 14$), and we comment on recent observations of super-solar nitrogen in GN-z11.

Impact of systematic nuclear uncertainties on composition and decay heat of dynamical and disc ejecta in compact binary mergers

ABSTRACT Theoretically predicted yields of elements created by the rapid neutron capture (r-)process carry potentially large uncertainties associated with incomplete knowledge of nuclear properties and approximative hydrodynamical modelling of the matter ejection processes. We present an in-depth study of the nuclear uncertainties by varying theoretical nuclear input models that describe the experimentally unknown neutron-rich nuclei. This includes two frameworks for calculating the radiative neutron capture rates and 14 different models for nuclear masses, β-decay rates, and fission properties. Our r-process nuclear network calculations are based on detailed hydrodynamical simulations of dynamically ejected material from NS–NS or NS–BH binary mergers plus the secular ejecta from BH–torus systems. The impact of nuclear uncertainties on the r-process abundance distribution and the early radioactive heating rate is found to be modest (within a factor of ∼20 for individual A > 90 abundances and a factor of 2 for the heating rate). However, the impact on the late-time heating rate is more significant and depends strongly on the contribution from fission. We witness significantly higher sensitivity to the nuclear physics input if only a single trajectory is used compared to considering ensembles with a much larger number of trajectories (ranging between 150 and 300), and the quantitative effects of the nuclear uncertainties strongly depend on the adopted conditions for the individual trajectory. We use the predicted Th/U ratio to estimate the cosmochronometric age of six metal-poor stars and find the impact of the nuclear uncertainties to be up to 2 Gyr.

High-efficiency promotion on dechlorination of polyvinyl chloride in subcritical water treatment by introducing waste concrete

Polyvinyl chloride (PVC) is one of the most widely used plastics in the world. Due to the generation of corrosive HCl and chlorine-containing organic pollutants during the recycling process, waste PVC can cause great environmental risks. At the same time, a large number of waste concrete in the construction industry have not been effectively utilized. Subcritical water (SubCW) has showed good prospect for treatment of PVC due to that dechlorination can be carried out with lower energy consumption. In this study, a high-efficiency and low-temperature SubCW treatment for dechlorination of PVC using waste concrete as an enhancer was proposed. The effects of temperature, residence time, solid-to-liquid ratio and PVC-to-Concrete ratio on dechlorination efficiency, chlorine distribution and weight loss ratio were studied. The PVC dechlorination efficiency could be enhanced to as high as 95.04% by introducing waste concrete. Significant dechlorination occurred under the conditions of 220 ℃, 60 min, solid-to-liquid ratio of 1:30 g/mL, and PVC-to-Concrete ratio of 4:1. Under the optimal conditions, all the removed chlorine from PVC was transferred into the liquid phase in the form of inorganic chlorine. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM), and elemental analysis were used to analyze the PVC dechlorination mechanism. The dechlorination pathway of PVC was found to include both direct dehydrochlorination and hydroxyl substitution. The enhancement mechanism of the waste concrete on the PVC dechlorination could be attributed to the rapid capture ability of CaCO3 for HCl. The SubCW-Concrete process proposed in this study was beneficial to both the low-temperature dechlorination of PVC and the resource utilization of waste concrete.

Powder-precursor integrated 3D-printed TiO2 photocatalyst and adsorption-degradation synergy effect

The practicability of nano-powder photocatalyst is limited by the difficulty of its recovery. 3D monolithic TiO2 photocatalyst (MTP) was printed by direct ink writing (DIW) using TiO2 nanoparticles as solutes of tetrabutyl titanate precursor to configure printing slurry to achieve integrated regulation of microscopic and macroscopic pore structure. The SEM verified that the surfaces of skeleton-TiO2 particles were uniformly covered by the TiO2 nanoparticles derived from calcining gel. And a highly connected hierarchical pore structure was formed by the skeleton-TiO2 particles and the designed 3D printing macroscopic pores, which laid the foundation for rapid capture and efficient in situ degradation of antibiotics. The nano TiO2 powders prepared by calcined gel have narrow band gap width, which is easier to generate electrons and holes and have low recombination rate. Therefore, the core-shell structure constructed by nanoparticles derived from gel and commercial TiO2 can effectively optimize the photocatalytic performance of MTP. The removal of tetracycline hydrochloride (TCCH) in water by MTP was used to verify the application effect of macro structure in practice, and the synergistic effect of adsorption and degradation kinetics was summarized. The dynamic adsorption effect of MTP reached 97.44 % at pH 7 for 5 h. Under simulated sunlight, MTP exhibited a synergistic adsorption-degradation effect, reaching equilibrium at 210 min. The cycle test shows that the removal rate of TCCH by MTP remains 91 % after 4 cycles. This strategy provides a good reference for the assembly of nanosemiconductor materials into environmentally friendly 3D structured systems.

Mass measurements show slowdown of rapid proton capture process at waiting-point nucleus 64Ge

AbstractX-ray bursts are among the brightest stellar objects frequently observed in the sky by space-based telescopes. A type-I X-ray burst is understood as a violent thermonuclear explosion on the surface of a neutron star, accreting matter from a companion star in a binary system. The bursts are powered by a nuclear reaction sequence known as the rapid proton capture process (rp process), which involves hundreds of exotic neutron-deficient nuclides. At so-called waiting-point nuclides, the process stalls until a slower β+ decay enables a bypass. One of the handful of rp process waiting-point nuclides is 64Ge, which plays a decisive role in matter flow and therefore the produced X-ray flux. Here we report precision measurements of the masses of 63Ge, 64,65As and 66,67Se—the relevant nuclear masses around the waiting-point 64Ge—and use them as inputs for X-ray burst model calculations. We obtain the X-ray burst light curve to constrain the neutron-star compactness, and suggest that the distance to the X-ray burster GS 1826–24 needs to be increased by about 6.5% to match astronomical observations. The nucleosynthesis results affect the thermal structure of accreting neutron stars, which will subsequently modify the calculations of associated observables.

Repeated Measurement of Microglia-Dendritic Spine Interactions Using Multi-Photon Imaging.

In recent decades, mounting evidence has shown that microglia play a vital role in maintaining synapses throughout life. This maintenance is done via numerous microglial processes, which are long, thin, and highly motile protrusions from the cell body that monitor their environment. However, due to the brevity of the contacts and the potentially transient nature of synaptic structures, establishing the underlying dynamics of this relationship has proven difficult. This article describes a method of using rapidly acquired multiphoton microscopy images to track microglial dynamics and microglia:synapse interactions and the fate of the synaptic structures following those interactions. First, we detail a method for capturing multiphoton images at 1-min intervals for approximately 1 hr and how that process can be done at multiple time points. We then discuss how best to prevent and account for any drifting of the region of interest that can occur during the imaging session and how to remove excessive background noise from those images. Finally, we detail the annotation process for dendritic spines and microglial processes using plugins in MATLAB and Fiji, respectively. These semi-automated plugins allow tracking of individual cell structures, even if both microglia and neurons are imaged in the same fluorescent channel. This protocol presents a method of tracking both microglial dynamics and synaptic structures, in the same animal, at multiple time points, giving the user information on process speed, branching, tip size, location, and dwell time, as well as any dendritic spine gains, losses, and size changes. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Rapid multiphoton image capture Basic Protocol 2: Image preparation using MATLAB and Fiji Basic Protocol 3: Dendritic spine and microglial processes annotation using ScanImage and TrackMate.

Reaction dynamics of molecules in highly electronically excited states attained by multiphoton and multiple excitation methods

Abstract Multiphoton absorption and multiple excitation can lead to the formation of highly electronically excited states of molecules. We have been applying these excitation methods to explore specific photochemical reactions, which are rather difficult to attain by normal one-photon absorption processes. In the present review, we will introduce several examples of these photochemical responses specific to highly excited state in the condensed phase, such as two-photon-gated cycloreversion, one-color control of both reactions in photochromic systems and rapid capture of an electron ejected from the higher excited state leading to rapid generation of charge-separated states at the high energy level with a lifetime much longer than microseconds.

3D porous carbon-embedded nZVI@Fe2O3 nanoarchitectures enable prominent performance and recyclability in antibiotic removal

Overcoming the instability and poor recyclability during the practical applications of contaminant scavengers is a challenging topic. Herein, a three-dimensional (3D) interconnected carbon aerogel (nZVI@Fe2O3/PC) embedding a core-shell nanostructure of nZVI@Fe2O3 was elaborately designed and fabricated via an in-situ self-assembly process. The porous carbon with 3D network architecture exhibits strong adsorption towards various antibiotic contaminants in water, where the stably embedded nZVI@Fe2O3 nanoparticles not only serve as magnetic seeds for recycling, but also avoid the shedding and oxidation of nZVI in the adsorption process. As a result, nZVI@Fe2O3/PC efficiently captures sulfamethoxazole (SMX), sulfamethazine (SMZ), ciprofloxacin (CIP), tetracycline (TC) and other antibiotics in water. In particular, an excellent adsorptive removal capacity of 329 mg g−1 and a rapid capture kinetics (99% of removal efficiency in 10 min) under a wide pH adaptability (2–8) are achieved using nZVI@Fe2O3/PC as an SMX scavenger. nZVI@Fe2O3/PC displays exceptional long-term stability given that it shows excellent magnetic property after it is stored in water solution for 60 d, making it an ideal stable scavenger for contaminants in an etching-resistant and efficient manner. This work would also provide a general strategy to develop other stable iron-based functional architectures for efficient catalytic degradation, energy conversion and biomedicine.

Abstract 1333: A novel and highly efficient biomimetic capture approach for the isolation and characterization of circulating metastatic cancer cell clusters from lung cancer patients

Abstract Capture and isolation of circulating metastatic cancer cell clusters (MCCC) is the essential first step to identify novel therapeutic targets focused on this important route of metastasis. We developed a unique biomimetic capture approach that allows selective isolation of these deadly clusters from the whole blood of lung cancer patients. Utilizing a microfluidic platform we developed a versatile smart-coating that combines biomimicry and immuno-capture for a highly efficient and selective isolation of viable MCCCs. Here we show the capture and characterization of multiple MCCCs from non-small cell lung cancer (NSCLC) patients. Table 1 shows the count of clusters detected in NSCLC patients based on a stringent criterion confirming their identification. The MCCCs were detected in every patient tested but none were detected in normal blood controls from donors of similar age. Isolated MCCC where characterized by immunofluorescence and submitted for genomic analyses. Metastasis remains one of the leading causes of cancer related deaths worldwide. Insights into how the tumor propagates to pre-metastatic sites is necessary to develop focused therapeutic approaches. Circulating metastatic cancer cell clusters (MCCCs) have been established as a primary entity causing distal metastases. Significant advances have been made linking cluster integrity and viability to increased metastatic potential highlighting the unmet need for cluster focused therapies. Our novel approach allows the rapid and easy capture of MCCCs paving the way for the discovery of novel or unique targets that eventually will bring new anti-metastatic therapies to the clinic. Table 1 Patient Age/Sex Staging/Metastasis #MCCC INMC-044.1 82 M IVB/bone 2 INMC-044.2 53 F IV/bone 1 INMC-044.3 59 F IV/bone, brain 2 INMC-044.4 65 M IV/thoracic cav., lung 1 INMC-044.5 67 M IIIa/none 3 Normal Blood 54 F N/A 0 Normal Blood 68 M N/A 0 Citation Format: Kourosh Kouhmareh, Erika Martin, Darren Finlay, Anukriti Bhadada, Francisco Downey, Jeff A. Allen, Peter Teriete. A novel and highly efficient biomimetic capture approach for the isolation and characterization of circulating metastatic cancer cell clusters from lung cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1333.

A Collapsar Origin for GRB 211211A Is (Just Barely) Possible

Gamma-ray bursts (GRBs) have historically been divided into two classes. Short-duration GRBs are associated with binary neutron star mergers (NSMs), while long-duration bursts are connected to a subset of core-collapse supernovae (SNe). GRB 211211A recently made headlines as the first long-duration burst purportedly generated by an NSM. The evidence for an NSM origin was excess optical and near-infrared emission consistent with the kilonova observed after the gravitational-wave-detected NSM GW170817. Kilonovae derive their unique electromagnetic signatures from the properties of the heavy elements synthesized by rapid neutron capture (the r-process) following the merger. Recent simulations suggest that the “collapsar” SNe that trigger long GRBs may also produce r-process elements. While observations of GRB 211211A and its afterglow rule out an SN typical of those that follow long GRBs, an unusual collapsar could explain both the duration of GRB 211211A and the r-process-powered excess in its afterglow. We use semianalytic radiation transport modeling to evaluate low-mass collapsars as the progenitors of GRB 211211A–like events. We compare a suite of collapsar models to the afterglow-subtracted emission that followed GRB 211211A, and find the best agreement for models with high kinetic energies and an unexpected pattern of 56Ni enrichment. We discuss how core-collapse explosions could produce such ejecta, and how distinct our predictions are from those generated by more straightforward kilonova models. We also show that radio observations can distinguish between kilonovae and the more massive collapsar ejecta we consider here.

Amine-impregnated porous carbon–silica sheets derived from vermiculite with superior adsorption capability and cyclic stability for CO2 capture

Amine-functionalized adsorbents have become one of the most promising capture technologies for greenhouse gas mitigation. However, developing cost-effective adsorbents with high adsorption capacity and superior cyclic stability via temperature swing adsorption remains difficult. Herein, sandwich-like polyethyleneimine (PEI)-impregnated porous carbon–silica sheets derived from vermiculite (AEVCP) adsorbents were successfully synthesized via porous carbon network confined within acid activated expanded vermiculite derived silica (AEV) sheets and interlayer amine-functionalization with PEI impregnation. The effect of adsorption temperature on CO2 adsorption performances, adsorption/desorption kinetics and thermodynamics for AEVCP adsorbents were specifically discussed. The optimal AEVCP50 adsorbent possessed a large CO2 uptake of 1.84 mmol/g at 75 ℃ in 60 vol% CO2/40 vol% N2 and superior cyclic stability with 7.6 % decay after 10 cycles, due to the hierarchical porous structure and high thermal conductivity of porous carbon–silica sheets derived from vermiculite (AEVC) support. The unique sandwich-like features of AEVC support are favorable for the high amine loading, rapid CO2 diffusion and efficient capture. The interlayer carbon implantation and amine-functionalization with strong interlayer spatial confinement effect, can suppress the formation of urea linkages, avoid the persistent over-heating and excess amine agglomeration, and enhance the gas diffusion and thermal transfer during the adsorption isobar process, which ultimately lead to superior adsorption capability and cyclic stability for CO2 capture. This design approach of cost-effective adsorbents derived from natural minerals provides a new avenue for practical CO2 capture and separation processes.

Preparation of Porous Composite Phase Na Super Ionic Conductor Adsorbent by In Situ Process for Ultrafast and Efficient Strontium Adsorption from Wastewater

Strontium, the main component of radioactive nuclear wastewater, is characterized by a high fission yield and an extended half-life. It is easily absorbed by the human body, thus greatly threatening the environment and the human body. In this study, a mesoporous composite phase sodium superionic conductor (NVP@NMP) was synthesized by the droplet template method, and the rapid capture of Sr2+ from wastewater was achieved by constructing a nano-heterogeneous interface to increase the ion diffusion rate. NVP@NMP showed efficient and rapid removal of strontium ions in adsorption kinetics, isothermal adsorption, solution pH, and interfering ions concentration tests, especially using the equilibrium time of 2 min for strontium absorption by NVP@NMP and a maximum theoretical adsorption capacity of 361.36 mg/g. The adsorption process was spontaneous, endothermic, and feasible. At higher concentrations of other competing ions (Na, K, Ca, Mg, and Cs), the adsorbent exhibited higher selectivity towards Sr2+.TEM, XPS, and XRD analyses revealed that ion exchange was the main mechanism for the NVP@NMP ultrafast adsorption of Sr2+. In this research, we investigated the feasibility of ultrafast strontium capture by sodium superionic conductor structured phosphates and explained the ultrafast strontium adsorption mechanism of NASICON materials through XPS.

Rapid capture of flow carbon dioxide by hard Epoxy thermosets with the high glass transition temperature

Rapid capture of flow carbon dioxide by hard Epoxy thermosets with the high glass transition temperature

Post-modified ligand exchange of UiO-66 with high-exposure rhodanine sites for enhancing the rapid and selective capture of Ag(I) from wastewater

Highly efficient capturing of silver from wastewater is critical for environmental and economic sustainability but remains significantly challenging to achieve fast kinetics and precise selectivity. Herein, we present two approaches based on rhodanine (Rd)-modified UiO-66 including post-modified ligand exchange for UiO-66-Rdp-m and in-situ solvothermal for UiO-66-Rdi-s. The resultant UiO-66-Rdp-m and UiO-66-Rdi-s perform maximum adsorption capacity of 120 and 109 mg·g−1, respectively, which are both about 6 times higher than pristine UiO-66. Benefitting from high-exposure Rd groups over the surface, UiO-66-Rdp-m exhibits about 3 times faster kinetic adsorption and nearly 15 times higher maximum selectivity coefficient than UiO-66-Rdi-s. Experiment and calculation demonstrate that the excellent performance of Rd-modified UiO-66 is dominantly owing to S chelation in the Rd group. In addition, site energy distributions of the Dubinin-Ashtakhov isotherm model confirm that UiO-66-Rdp-m has more effective sites for Ag(I) adsorption relative to UiO-66-Rdi-s. While a higher density of Rd outside the UiO-66-Rdp-m provides a larger coordination number of S/Ag (1.41) than UiO-66-Rdi-s (0.59), which is attributed to its sufficient exposed active S sites for multidentate coordination of Ag(I), thus significantly enhancing adsorption rate and selectivity. These findings are exploited to shed new insight into the design of adsorbents for the efficient recycling of noble metals from water.

Kilonova Emission and Heavy Element Nucleosynthesis

The binary neutron star merger observed and localized on 17 August 2017 by the LIGO and Virgo gravitational interferometers and by numerous telescopes on the ground and in orbit linked in an unambiguous way the coalescence of double neutron stars with the formation of a relativistic outflow (short gamma-ray burst GRB170817A) and of a thermal radioactive source (kilonova). The vicinity of the event (40 Mpc) made it possible to monitor the electromagnetic counterpart in detail at all wavelengths and to map its close environment in the outskirts of the lenticular galaxy NGC 4993. Radio VLBI images of GRB170817A allowed the first direct detection of superluminal motion in a GRB afterglow, pointing to a collimated ultra-relativistic jet rather than to a quasi-isotropically, mildly relativistically expanding source. The accurate spectroscopy of the kilonova at ultraviolet-to-infrared wavelengths with the X-Shooter spectrograph of the ESO Very Large Telescope showed the long-sought-after signature of rapid neutron capture process (in short: r-process) nucleosynthesis. Kilonova detection makes gravitational wave sources optimal tracers of heavy element formation sites.

Targeting Mucin Protein Enables Rapid and Efficient Ovarian Cancer Cell Capture: Role of Nanoparticle Properties in Efficient Capture and Culture.

The development of specific and sensitive immunomagnetic cell separation nanotechnologies is central to enhancing the diagnostic relevance of circulating tumor cells (CTCs) and improving cancer patient outcomes. The limited number of specific biomarkers used to enrich a phenotypically diverse set of CTCs from liquid biopsies has limited CTC yields and purity. The ultra-high molecular weight mucin, mucin16(MUC16) is shown to physically shield key membrane proteins responsible for activating immune responses against ovarian cancer cells and may interfere with the binding of magnetic nanoparticles to popular immunomagnetic cell capture antigens. MUC16 is expressed in ≈90% of ovarian cancers and is almost universal in High Grade Serous Epithelial Ovarian Cancer. This work demonstrates that cell bound MUC16 is an effective target for rapid immunomagnetic extraction of expressor cells with near quantitative yield, high purity and viability from serum. The results provide a mechanistic insight into the effects of nanoparticle physical properties and immunomagnetic labeling on the efficiency of immunomagnetic cell isolation. The growth of these cells has also been studied after separation, demonstrating that nanoparticle size impacts cell-particle behavior and growth rate. These results present the successful isolation of "masked" CTCs enabling new strategies for the detection of cancer recurrence and select and monitor chemotherapy.

Loofah sac-like three-dimensional interwoven network composed of Van-PEG-MWCNTs for rapid and efficient capture of Staphylococcusaureus

In this work, a three-dimensional interwoven network composed of Van-PEG-MWCNTs was successfully constructed for the capture of Staphylococcus aureus. The capture behavior of this network against Staphylococcus aureus in simulated solution and real milk was studied. Grafting Van-PEG on carbon nanotubes endowed carbon nanotubes with activity against Staphylococcus aureus, and improved the dispersibility of carbon nanotubes in solution system at the same time, so that they can be suspended in solution uniformly and form a loofah-like three-dimensional structure, enabling the grafted complex to capture Staphylococcus aureus efficiently in the solution system, even the low-level target bacteria can also be captured. The results showed that Van-PEG-MWCNTs played a role as molecular probes that can identify and capture Staphylococcus aureus from phosphate-buffered saline solution and fresh milk samples with a LOD of 2 × 101 CFU/mL. This study demonstrated the potential application value of Van-PEG-MWCNTs for rapid and efficient detection of Staphylococcus aureus.

Introduction of multilayered magnetic core–dual shell SERS tags into lateral flow immunoassay: A highly stable and sensitive method for the simultaneous detection of multiple veterinary drugs in complex samples

Direct, convenient, and sensitive monitoring of the residues of multiple drugs in complex environments is important but remains a challenge. Here, we report a surface-enhanced Raman scattering (SERS)-based multiplexed lateral flow immunoassay (LFA) that supports the simultaneous and sensitive detection of commonly used drugs kanamycin, ractopamine, clenbuterol, and chloramphenicol in unprocessed complex samples through the dual signal amplification strategy of numerous efficient hotspots and magnetic enrichment. Multilayered magnetic-core dual-shell nanoparticles (MDAu@Ag) with controllable subtle nanogaps were fabricated via the polyethyleneimine-mediated layer-by-layer (LBL) assembly of two layers of Au@Ag satellites onto superparamagnetic Fe3O4 cores and conjugated with specific antibodies as multifunctional tags in the LFA system for rapid capture, separation, and quantitative analysis. Two Raman reporters were embedded in internal nanogaps and modified on the surface of MDAu@Ag for the simultaneous and ultrasensitive detection of four targets on two test lines, which greatly simplified the fabrication and signal reading of SERS-LFA. The proposed assay can rapidly detect multiple drug residues in 35 min with detection limits down to pg/mL level. Moreover, the MDAu@Ag–based SERS-LFA demonstrated better stability, higher throughput, and superior sensitivity (at least 400 times) than traditional colloidal gold immunochromatography, showing its great potential in the field of point-of-care testing.

Actin-driven chromosome clustering facilitates fast and complete chromosome capture in mammalian oocytes

Accurate chromosome segregation during meiosis is crucial for reproduction. Human and porcine oocytes transiently cluster their chromosomes before the onset of spindle assembly and subsequent chromosome segregation. The mechanism and function of chromosome clustering are unknown. Here we show that chromosome clustering is required to prevent chromosome losses in the long gap phase between nuclear envelope breakdown and the onset of spindle assembly, and to promote the rapid capture of all chromosomes by the acentrosomal spindle. The initial phase of chromosome clustering is driven by a dynamic network of Formin-2- and Spire-nucleated actin cables. The actin cables form in the disassembling nucleus and migrate towards the nuclear centre, moving the chromosomes centripetally by interacting with their arms and kinetochores as they migrate. A cage of stable microtubule loops drives the late stages of chromosome clustering. Together, our data establish a crucial role for chromosome clustering in accurate progression through meiosis.