YTHDF1 enhances stemness and chemoresistance in triple-negative breast cancer cells by upregulating SIAH2.

Triple-negative breast cancer (TNBC) is the most lethal and aggressive subtype of breast cancer, and chemoresistance is the major determinant of TNBC treatment failure. This study explores the molecular mechanism of TNBC chemoresistance. The Cancer Genome Atlas, breast cancer integrative platform, and GEPIA databases were used to analyze the expression and correlation of YTHDF1 and seven in absentia homology 2 (SIAH2) in breast cancer. Knockdown of YTHDF1 and SIAH2, or overexpression of SIAH2 in vitro and in vivo, was conducted to evaluate the impact of changes in YTHDF1 and SIAH2 expression on TNBC cell proliferation, apoptosis, stemness, drug resistance, and Hippo pathway gene expression. YTHDF1 and SIAH2 were highly expressed in breast cancer patients and TNBC cells. Knockdown of YTHDF1 and SIAH2 significantly inhibited proliferation and stemness and promoted apoptosis and chemosensitivity of TNBC cells. Mechanistically, the knockdown of YTHDF1 inhibited the expression of SIAH2, thereby downregulating the Hippo pathway, which inhibited proliferation and stemness and promoted apoptosis and chemosensitivity of TNBC cells. The current findings revealed the regulatory mechanism of YTHDF1 in TNBC and clarified the role of the YTHDF1/SIAH2 axis in TNBC drug resistance and stemness. This could provide new insights into the vital role of targeting YTHDF1/SIAH2 to suppress drug resistance and stemness in TNBC cells.

Investigation on acceptor-donor co-doped SnO2 nanoparticles enriched with oxygen vacancies: a capacitive humidity sensor for respiration detection.

In this work, we develop a novel capacitive humidity sensor based on Al-Si acceptor-donor co-doped SnO2 for real-time monitoring of ambient humidity and human respiration. XRD measurements reveal that all samples exhibit a tetragonal rutile phase and the crystallite size of SnO2 decreases with increasing Al-Si content. The high intensity of the Raman peak at 762 cm-1 confirms the presence of bridging mode oxygen vacancies in (Al + Si)0.02Sn0.98O2. The EPR results show that the amount of singly ionized oxygen vacancies increases after the introduction of Al-Si. Both types and amounts of oxygen vacancy defects are particularly sensitive to the adsorption of water molecules. Moreover, according to DFT calculations, the contribution of the Si 3s orbital and Al 3s orbital to the band edge verifies the formation of acceptor-donor complexes in Al-Si co-doped SnO2. The humidity sensing results reveal that the (Al + Si)0.02Sn0.98O2 humidity sensor shows high sensitivity (S = 839), low hysteresis (1.94%) and fast response/recovery times (25 s/5 s). The respiratory intervals during shallow, medium and deep breathing states of (Al + Si)0.02Sn0.98O2 were measured at 2.8 s, 3.8 s and 4.5 s, respectively. The chemical mechanism for the enhancement of humidity sensing performance corresponding to the oxygen vacancy defects induced by Al-Si interplay is proposed.

Study on the correlation of C-reactive protein/albumin ratio with sudden sensorineural hearing loss complicated by hypertension: a prospective study.

BACKGROUND: Understanding the pathophysiology of sudden sensorineural hearing loss (SSNHL) and identifying its clinical symptoms and associated risk factors are crucial for doctors in order to create effective prevention and therapeutic methods for this prevalent otolaryngologic emergency. METHODS: This study focuses on investigating the correlation between the C-reactive protein/albumin ratio (CAR) and SSNHL complicated by hypertension. In this study, 120 patients diagnosed with SSNHL were divided into groups with and without hypertension, and propensity score matching was used to compare and analyze the severity, type, prognosis, and CAR levels in SSNHL. RESULTS: The results showed that the SSNHL group with hypertension had significantly higher CAR levels, age, hearing curve abnormalities, and more severe hearing loss compared to the control group with isolated SSNHL. These differences were statistically significant (p < 0.001). Among different subtypes of SSNHL, CAR levels increased progressively with the advancement of the condition, and these differences were also statistically significant (p < 0.001). CONCLUSION: In summary, in patients with SSNHL, those with hypertension had higher CAR levels than those without a history of hypertension, and they experienced more severe hearing loss. Moreover, there was a clear correlation between CAR levels and the extent of SSNHL, indicating that greater CAR levels in patients with SSNHL are connected to more severe hearing loss in various hearing patterns and perhaps indicative of a poorer prognosis.

RBM3 is associated with acute lung injury in septic mice and patients via the NF-κB/NLRP3 pathway.

Sepsis refers to host response disorders caused by infection, leading to life-threatening organ dysfunction. RNA-binding motif protein 3 (RBM3) is an important cold-shock protein that is upregulated in response to mild hypothermia or hypoxia. In this study, we aimed to investigate whether RBM3 is involved in sepsis-associated acute lung injury (ALI). Intraperitoneal injection of LPS (10 mg/kg) was performed in wild type (WT) and RBM3 knockout (KO, RBM3-/-) mice to establish an in vivo sepsis model. An NLRP3 inflammasome inhibitor, MCC950 (50 mg/kg), was injected intraperitoneally 30 min before LPS treatment. Serum, lung tissues, and BALF were collected 24 h later for further analysis. In addition, we also collected serum from sepsis patients and healthy volunteers to detect their RBM3 expression. The results showed that the expression of RBM3 in the lung tissues of LPS-induced sepsis mice and the serum of patients with sepsis was significantly increased and positively correlated with disease severity. In addition, RBM3 knockout (KO) mice had a low survival rate, and RBM3 KO mice had more severe lung damage, inflammation, lung cell apoptosis, and oxidative stress than WT mice. LPS treatment significantly increased the levels of nucleotide binding and oligomerization domain-like receptor family 3 (NLRP3) inflammasomes and mononuclear cell nuclear factor-κB (NF-κB) in the lung tissues of RBM3 KO mice. However, these levels were only slightly elevated in WT mice. Interestingly, MCC950 improved LPS-induced acute lung injury in WT and RBM3 KO mice but inhibited the expression of NLRP3, caspase-1, and IL-1ß. In conclusion, RBM3 was overexpressed in sepsis patients and LPS-induced mice. RBM3 gene deficiency aggravated sepsis-associated ALI through the NF-κB/NLRP3 pathway.

Effect of different substituents on the fluorescence properties of precursors of synthetic GFP analogues and a polarity-sensitive lipid droplet probe with AIE properties for imaging cells and zebrafish.

The green fluorescent protein (GFP) is a purely natural specialty protein that has been widely used to design synthetic fluorescent probes. In the present work we designed and synthesized a series of fluorescent compounds akin to GFP precursors by a one-step method, and investigated the luminescence properties of the fluorescent compounds by varying the substituents. We presented the first systematic summary of the photophysical data including extinction coefficients and fluorescence quantum yields for this class of fluorescent dyes. We also carried out density functional theory (DFT) calculations for these dyes to investigate the effect of electronic effects due to different substituents. These studied optical properties may provide a reference for later probe design. More interestingly, we have developed a polarity-sensitive lipid droplet probe T-LD with AIE properties on this basis. The probe exhibited not only favorable pH stability and kinetic stability in terms of optical properties, but also solvent discolouration and polarity-sensitive properties, and was able to label intracellular lipid droplets. We successfully applied the probe for intracellular lipid droplet level monitoring and zebrafish imaging.

Hippo/YAP signaling pathway protects against neomycin-induced hair cell damage in the mouse cochlea.

The Hippo/Yes-associated protein (YAP) signaling pathway has been shown to be able to maintain organ size and homeostasis by regulating cell proliferation, differentiation, and apoptosis. The abuse of aminoglycosides is one of the main causes of sensorineural hearing loss (SSNHL). However, the role of the Hippo/YAP signaling pathway in cochlear hair cell (HC) damage protection in the auditory field is still unclear. In this study, we used the YAP agonist XMU-MP-1 (XMU) and the inhibitor Verteporfin (VP) to regulate the Hippo/YAP signaling pathway in vitro. We showed that YAP overexpression reduced neomycin-induced HC loss, while downregulated YAP expression increased HC vulnerability after neomycin exposure in vitro. We next found that activation of YAP expression inhibited C-Abl-mediated cell apoptosis, which led to reduced HC loss. Many previous studies have reported that the level of reactive oxygen species (ROS) is significantly increased in cochlear HCs after neomycin exposure. In our study, we also found that YAP overexpression significantly decreased ROS accumulation, while downregulation of YAP expression increased ROS accumulation. In summary, our results demonstrate that the Hippo/YAP signaling pathway plays an important role in reducing HC injury and maintaining auditory function after aminoglycoside exposure. YAP overexpression could protect against neomycin-induced HC loss by inhibiting C-Abl-mediated cell apoptosis and decreasing ROS accumulation, suggesting that YAP could be a novel therapeutic target for aminoglycosides-induced sensorineural hearing loss in the clinic.

The value of inflammatory biomarkers in the occurrence and prognosis of sudden sensorineural hearing loss: a meta-analysis.

OBJECTIVES: Sudden sensorineural hearing loss (SSNHL) is one of the common emergencies in otorhinolaryngology. Several studies have shown that chronic inflammation is associated with its onset and prognosis. However, the association between some inflammatory biomarkers and SSNHL is still unclear. Therefore, we conducted this meta-analysis to explore the value of inflammatory biomarkers in the occurrence and prognosis of SSNHL. METHODS: Pubmed, Embase, Cochrane and Web of Science databases were searched comprehensively, the eligible literatures were screened out by formulating the inclusion criteria and exclusion criteria. After extracting sample size, mean and standard deviation, we performed meta-analysis with standardized mean deviation (SMD) and 95% confidence interval (CI) as effect sizes. RESULTS: A total of 17 articles were included in this meta-analysis, including 2852 subjects, 1423 patients and 1429 healthy controls. The results of meta-analysis showed that the neutrophil-to-lymphocyte ratio (NLR) of the experimental group was significantly higher than the control group (SMD = 1.05, 95% CI 0.87-1.24, P < 0.001), the NLR of the recovery group was significantly lower than the unrecovered group (SMD = 0.68, 95% CI 0.27-1.08, P < 0.05); The platelet-to-lymphocyte ratio (PLR) of the experimental group was significantly higher than the control group (SMD = 0.55, 95% CI 0.34-0.76, P < 0.05), the PLR of the recovery group was significantly lower than the unrecovered group (SMD = 0.44, 95% CI 0.05-0.82, P < 0.05); The C-reactive protein-to-serum albumin ratio (CRP/Alb) of the experimental group was significantly higher than the control group (SMD = 0.39, 95% CI 0.04-0.74, P < 0.05). CONCLUSIONS: The results showed that high NLR, PLR, and CRP/Alb indicated the occurrence of SSNHL, NLR and PLR could predict prognosis of SSNHL.

Three-color reflections in one-dimensional ordered and disordered atomic lattices with trapped N-type cold atoms.

Investigating and controlling light propagation in one-dimensional (1D) ordered and disordered atomic lattices is critical both fundamentally and for applications. In this study, cold atoms are trapped in 1D optical lattice and driven to the four-level N configuration. In each period, the atoms exhibit a Gaussian density distribution with the average atomic density N0 (1 + Δk). When the random number Δk = 0 (the atomic density Nk(z)) corresponding to an ordered 1D atomic lattice, there are three reflection regions of high reflectivity located in two EIT windows and one large detuning range. However, the atomic density may increase (N k+(z) with Δk > 0) or decrease (N k-(z) with Δk < 0) owing to the imperfect manufacturing process or random distribution of atoms corresponding to a disordered atomic lattice. The results show that the width and height of reflections can be raised (reduced) by the increased (decreased) ratio of N k+(z)/N k (z) (N k-(z)/N k (z)) with the random distribution of lattice cells with N k+(z) (N k-(z)). When a cluster of disordered lattice cells with N k+(z) and N k-(z) is located at the front or tail of the atomic lattice, reflection symmetry can be broken. However, the symmetry and robustness can be well preserved with the random fluctuation of the average atomic density in each lattice cell.

Clinical efficacy and safety of MP-AzeFlu for the treatment of allergic rhinitis: a meta-analysis.

OBJECTIVE: MP-AzeFlu is a novel option for therapy of allergic rhinitis (AR). The purpose of our study was to assess the safety and efficacy of MP-AzeFlu for the treatment of allergic rhinitis, compared to placebo and azelastine monotherapy. METHODS: The PubMed, MEDLINE, EMBASE and Cochrane databases were comprehensively searched for all published randomized controlled trials (RCTs) of using MP-AzeFlu nasal spray on July 26, 2019. In these studies, we selected patients with clinical symptom scores. The heterogeneity of the included studies was assessed by I2. RESULTS: Among the 336 citations retrieved, 6 articles with over 6000 patients were finally included in the meta-analysis. The results of meta-analysis revealed that MP-AzeFlu was superior to placebo ( - 2.43 [95%CI,  - 2.73 to  - 2.14], P < 0.00001) and azelastine ( - 1.27 [95% CI,  - 1.57 to  - 0.97], P < 0.00001) in reflective total nasal symptom score. In the MP-AzeFlu group, the instantaneous total nasal symptom score ( - 2.56 [95% CI,  - 3.02 to  - 2.10], P < 0.00001) and the reflective total ocular symptom score ( - 1.22 [95% CI,  - 1.57 to  - 0.87], P < 0.00001) were significantly reduced compared to the placebo group. CONCLUSION: MP-AzeFlu is as safe and mild as placebo and azelastine, which also is associated with symptom relief and the improvement of quality of life in AR patients. MP-AzeFlu can provide better clinical benefits than two currently available first-line intranasal therapies. It is an ideal therapy for AR patients.

Dynamic manipulation of three-color light reflection in a defective atomic lattice.

We extend a recent theoretical work [Phys. Rev. A101, 053856 (2020)10.1103/PhysRevA.101.053856] by replacing disorders characterized by varied atomic densities with defects characterized by vacant lattice cells to evaluate again three-color reflection in a one-dimensional optical lattice filled with cold 87Rb atoms. This is based on the consideration that trapped atoms may escape from some lattice cells and effects of vacant cells on light propagation are of major importance from both fundamental and applied research viewpoints. We consider two types of defective atomic lattices where vacant cells are randomly or continuously distributed among filled cells. Numerical results show that the wider reflection band in a large detuning region of negligible off-resonance absorption is quite sensitive to, while the narrower reflection bands in two near-resonant regions of electromagnetically induced transparency are rather robust against, the number of random vacant cells. In contrast, all three reflection bands exhibit strong robustness against the number of continuous vacant cells. Note, however, that both narrower reflection bands may become widened and exhibit a blue shift when continuous vacant cells appear in the front of our atomic lattice due to the joint contributions of Bragg scattering and quantum interference.

RBM3 Increases Cell Survival but Disrupts Tight Junction of Microvascular Endothelial Cells in Acute Lung Injury.

BACKGROUND: RNA-binding motif protein 3 (RBM3) is an important cold shock protein, which also responds to hypothermia or hypoxia. RBM3 is involved into multiple physiologic processes, such as promoting cell survival. However, its expression and function in acute lung injury (ALI) have not been reported. METHODS: A mouse ALI model was established by lipopolysaccharides (LPS) treatment. The RBM3 and cold inducible RNA-binding protein mRNA levels were examined by RT-qPCR, and MMP9 mRNA stability was determined by actinomycin D assay. RBM3 and MMP9 mRNA was tested by RNA immunoprecipitation (RIP assay). RBM3 overexpression or silent stable cell lines were established using recombinant lentivirus and subsequently used for cell survival and tight junction measurements. RESULTS: In this study, we found that RBM3, rather than cold inducible RNA-binding protein, was upregulated in lung tissue of ALI mice. RBM3 was increased in human pulmonary microvascular endothelial cells (HPMVECs) in response to LPS treatment, which is modulated by the NF-κB signaling pathway. Furthermore, RBM3 could reduce cell apoptosis induced by LPS, probably through suppressing p53 expression. Because increased permeability of HPMVECs leads to pulmonary edema in ALI, we subsequently examined the effect of RBM3 on cell tight junctions. Unexpectedly, RBM3 decreased the expression of tight junction protein zonula occludens-1 and increased cell permeability, and RBM3 overexpression increased MMP9 mRNA stability. Furthermore, RIP assay confirmed the interaction between RBM3 and MMP9 mRNA, possibly explaining the contribution of RBM3 to increase cell permeability. CONCLUSIONS: RBM3 seems to act as a "double-edged sword" in ALI, that RBM3 alleviates cell apoptosis but increases HPMVEC permeability in ALI.

Risk factors of pharyngocutaneous fistula after total laryngectomy: a systematic review and meta-analysis.

OBJECTIVE: The purpose of this study was to systematically evaluate the risk factors of pharyngocutaneous fistula (PCF) after total laryngectomy. METHODS: We systematically searched Pubmed, Web of Science, Cochrane Library, and Embase databases and included the literature according to the inclusion and exclusion criteria. RESULTS: A total of 52 studies with 8605 patients were included in the meta-analysis. The total incidence of PCF was 21% (1808/8605). Meta-analysis results indicated that age (OR = 1.29, 95% CI 1.06-1.58, P = 0.01), smoking (OR = 1.62, 95% CI 1.27-2.07, P < 0.01), COPD (chronic obstructive pulmonary disease) (OR = 1.62, 95% CI 1.19-2.22, P < 0.01), CAD (coronary atherosclerotic heart disease) (OR = 1.82, 95% CI 1.36-2.45, P < 0.01), T-stage (OR = 0.81, 95% CI 0.67-0.98, P = 0.03), previous radiotherapy (OR = 2.41, 95% CI 2.00-2.90, P < 0.01), preoperative albumin (OR = 2.95, 95% CI 1.47-5.91, P < 0.01), preoperative hemoglobin (OR = 1.97, 95% CI 1.28-3.03, P < 0.01), tumor site (OR = 0.28, 95% CI 0.22-0.36, P < 0.01), and treatment method (OR = 1.85, 95% CI 1.44-2.38, P < 0.01) were risk factors associated with PCF. CONCLUSIONS: In our study, age, smoking, COPD, CAD, T-stage, previous radiotherapy, preoperative albumin, preoperative hemoglobin, tumor site, and treatment method were risk factors of PCF.

A colorimetric immunosensor for determination of foodborne bacteria using rotating immunomagnetic separation, gold nanorod indication, and click chemistry amplification.

A colorimetric immunosensor was developed for the determination of Salmonella Typhimurium using rotating magnetic separation, gold nanorod (GNR) indication, and click chemistry amplification. The target bacteria were first separated from large-volume sample using a rotating magnetic field and a small amount (50 µg) of immunomagnetic nanoparticles (MNPs), resulting in the forming of magnetic bacteria. Then, the magnetic bacteria were conjugated with catalase (CAT)-labeled antibodies, which were synthesized using trans-cyclooctene/1,2,4,5-tetrazine click chemistry reaction, resulting in the forming of enzymatic bacteria. Then the CATs on the enzymatic bacteria were used to decompose an excessive amount of hydrogen peroxide (H2O2), the remaining H2O2 was mixed with horseradish peroxidase to etch the GNRs, resulting in color change and absorbance peak shift of the GNRs. Finally, the peak shift was measured and analyzed for the quantitative determination of target bacteria. This immunosensor was able to detect Salmonella Typhimurium with a linear range of 101-105 CFU mL-1 in 3 h with a low detection limit of 35 CFU mL-1. The mean recovery for Salmonella Typhimurium in spiked chicken samples was 109%. Graphical abstractSchematic representation of a colorimetric immunosensor for the determination of Salmonella Typhimurium as low as 35 CFU mL-1 using rotating magnetic separation of Salmonella from a large-volume sample, click chemistry reaction of catalase with antibodies for signal amplification, and HRP-mediated gold nanorod etching for result indication.

An All-Solid-State Nitrate Ion-Selective Electrode with Nanohybrids Composite Films for In-Situ Soil Nutrient Monitoring.

In this paper, an all-solid-state nitrate doped polypyrrole (PPy(NO3-) ion-selective electrode (ISE) was prepared with a nanohybrid composite film of gold nanoparticles (AuNPs) and electrochemically reduced graphene oxide (ERGO). Preliminary tests on the ISE based in-situ soil nitrate-nitrogen (NO3--N) monitoring was conducted in a laboratory 3-stage column. Comparisons were made between the NO3--N content of in-situ soil percolate solution and laboratory-prepared extract solution. Possible influential factors of sample depth, NO3--N content, soil texture, and moisture were varied. Field-emission scanning electron microscopy (FESEM) and X-ray powder diffraction (XRD) characterized morphology and content information of the composite film of ERGO/AuNPs. Due to the performance excellence for conductivity, stability, and hydrophobicity, the ISE with ERGO/AuNPs illustrates an acceptable detection range from 10-1 to 10-5 M. The response time was determined to be about 10 s. The lifetime was 65 days, which revealed great potential for the implementation of the ERGO/AuNPs mediated ISE for in-situ NO3--N monitoring. In-situ NO3--N testing results conducted by the all-solid-state ISE followed a similar trend with the standard UV-VIS method.

Reduction of Cold Ischemic Injury with the Addition of Compound Glycyrrhizin in HTK Solution in a Mouse Heart Transplantation Model.

Cold ischemic injury in heart storage is an important issue pertaining to heart transplantation. This study aims to evaluate the addition of compound glycyrrhizin (CG) in histidine-tryptophan-ketoglutarate (HTK) solution on chronic isograft injury in comparison to traditional HTK solution.Hearts of mouse were stored for 8 h in 4°C cold preservation solution and then transplanted heterotopically into mouse. Five groups were evaluated: HTK, low dose of CG solution (LCG), medium dose of CG solution (MCG), high dose of CG solution (HCG), and hearts without cold ischemia (sham). Survival was assessed. Time to restoration of heartbeat and strength of the heartbeat was measured. Lactate dehydrogenase (LDH) and creatine kinase (CK) levels in the preservation solution were determined. The myocardial damage and interstitial fibrosis of transplanted hearts were evaluated. TGF-ß1 expression in the transplanted hearts was assessed.Addition of CG to HTK solution significantly attenuated cold ischemic injury during cold storage, as evidenced by the lower time to restoration of heartbeat, higher strength of the heartbeat, lower LDH, and CK leakage. After transplantation, hearts stored in HTK solution containing CG had decreased the myocardial damage and interstitial fibrosis, compared with those stored without CG. The percentage of TGF-ß1-positive cells and TGF-ß1 level in the transplanted hearts were also decreased when stored in CG-containing HTK solution.The addition of CG to HTK solution attenuates cold ischemic injury during cold storage.

Bone marrow stromal cells transplantation promotes the resolution and recanalization of deep vein thrombosis in rabbits through regulating macrophage infiltration and angiogenesis.

This study aims to validate whether bone marrow stromal cells (BMSCs) transplantation could promote the resolution and recanalization of deep vein thrombosis (DVT) and to explore the underlying mechanism. The right hind femoral vein was embolized to establish the DVT rabbit model. BMSCs from New Zealand white rabbits were isolated and identified, and then injected into DVT rabbits. After that, the extent of angiogenesis was determined by the amount of capillaries that were positive for antibody against vWF. Macrophage infiltration was measured by immunohistochemistry with F4/80 antibody. M1 or M2 macrophages were identified as F4/80 + CD11c + or F4/80 + CD206 + cells by using flow cytometry analysis, respectively. BMSCs were successfully isolated and identified. BMSCs transplantation promotes macrophage infiltration and angiogenesis in DVT rabbits. BMSCs transplantation causes M1/M2 polarization, altered cytokine production and increased monocyte chemotactic protein 1 (MCP-1) protein expression in DVT rabbits. However, injection of MCP-1 protein not only reversed the effects of BMSCs transplantation on macrophage infiltration and angiogenesis, but also reversed the effects of BMSCs transplantation on M1/M2 polarization and cytokine production in DVT rabbits. BMSCs transplantation promotes the resolution and recanalization of DVT in rabbits through regulating macrophage infiltration and angiogenesis, the underlying mechanism is associated with MCP-1 expression.

A microfluidic immunosensor for visual detection of foodborne bacteria using immunomagnetic separation, enzymatic catalysis and distance indication.

A disposable visual microfluidic immunosensor is described for the determination of foodborne pathogens using immunomagnetic separation, enzymatic catalysis and distance indication. Specifically, a sensor was designed to detect Salmonella typhimurium as a model pathogen. Magnetic nanoparticles (MNPs) were modified with the anti-Salmonella monoclonal antibodies and then used to enrich S. typhimurium from the sample. This is followed by conjugation to polystyrene microspheres modified with anti-Salmonella polyclonal antibodies and catalase to form the MNP-bacteria-polystyrene-catalase sandwich. The catalase on the complexes catalyzes the decomposition of hydrogen peroxide to produce oxygen after passing a micromixer. The generated oxygen gas increases the pressure in the chip and pushes the indicating red dye solution to travel along the channel towards the unsealed outlet. The travel distance of the red dye can be visually read and related to the amount of S. typhimurium using the calibration scale. The sensor can detect as low as 150 CFU·mL-1 within 2 h. Graphical abstractSchematic representation of the distance-based microfluidic immunosensor for visual detection of foodborne bacteria using immunomagnetic nanoparticles for bacteria separation, catalase for decomposition of hydrogen peroxide to form oxygen which causes a pressure increase, and red dyed particles movement for distance indication.

An ISE-based On-Site Soil Nitrate Nitrogen Detection System.

Soil nitrate-nitrogen (NO3--N) is one of the primary factors used to control nitrogen topdressing application during the crop growth period. The ion-selective electrode (ISE) is a promising method for rapid lower-cost in-field detection. Due to the simplification of sample preparation, the accuracy and stability of ISE-based in-field detection is doubted. In this paper, a self-designed prototype system for on-site soil NO3--N detection was developed. The procedure of spinning centrifugation was used to avoid interference from soil slurry suspension. A modified Nernstian prediction model was quantitatively characterized with outputs from both the ISE and the soil moisture sensor. The measurement accuracy of the sensor fusion model was comparable with the laboratory ISE detections with standard sample pretreatment. Compared with the standard spectrometric method, the average absolute error (AE) and root-mean-square error (RMSE) were found to be less than 4.7 and 6.1 mg/L, respectively. The on-site soil testing efficiency was 4-5 min/sample, which reduced the operation time by 60% compared with manual sample preparation. The on-site soil NO3--N status was dynamically monitored for 42 consecutive days. The declining peak of NO3--N was observed. In all, the designed ISE-based detection system demonstrated a promising capability for the dynamic on-site monitoring of soil macronutrients.

Tunable, Sheathless Focusing of Diamagnetic Particles in Ferrofluid Microflows with a Single Set of Overhead Permanent Magnets.

There has been increasing interest in the use of magnetic fluids to manipulate diamagnetic particles in microfluidic devices. Current methods for diamagnetic-particle focusing in magnetic fluids require either a pair of repulsive magnets or a diamagnetic sheath flow. We demonstrate herein a tunable, sheathless focusing of diamagnetic particles in a microchannel ferrofluid flow with a single set of overhead permanent magnets. Particles are focused into a single stream near the bottom wall of a straight rectangular microchannel, where a magnetic-field minimum is formed as a result of the magnetization of the ferrofluid. This focusing can be readily switched off and on by removing and replacing the permanent magnets. More importantly, the particle-focusing position can be tuned by shifting the magnets with respect to the microchannel. We perform a systematic experimental study of the parametric effects of the fluid-particle-channel system on diamagnetic-particle focusing in terms of a defined particle-focusing effectiveness.

Simultaneous Separation and Washing of Nonmagnetic Particles in an Inertial Ferrofluid/Water Coflow.

Magnetic fluids (e.g., paramagnetic solutions and ferrofluids) have been increasingly used for label-free separation of nonmagnetic particles in microfluidic devices. Their biocompatibility, however, becomes a concern in high-throughput or large-volume applications. One way to potentially resolve this issue is resuspending the particles that are separated in a magnetic fluid immediately into a biocompatible buffer. We demonstrate herein the proof-of-principle of the first integration of negative magnetophoresis and inertial focusing for a simultaneous separation and washing of nonmagnetic particles in coflowing ferrofluid and water streams. The two operations take place in parallel in a simple T-shaped rectangular microchannel with a nearby permanent magnet. We find that the larger and smaller particles' exiting positions (and hence their separation distance) in the sheath water and ferrofluid suspension, respectively, vary with the total flow rate or the flow rate ratio between the two streams.