Purpose To develop and measure the reproducibility of 4-min whole brain myelin water fraction (MWF) mapping using fast acquisition with spiral trajectory and T2prep (FAST-T2) sequence at 3T. Methods Experiments were performed on phantoms, 13 volunteers, and 16 patients with multiple sclerosis. MWF maps were extracted using a spatially constrained non-linear algorithm. The proposed adiabatic modified BIR-4 (mBIR-4) T2prep was compared with the conventional composite T2prep (COMP). The effect of reducing the number of echo times (TEs) from 15 to 6 (reducing scan time from 10 to 4 min) was evaluated. Reproducibility was assessed using correlation analysis, coefficient of variation (COV), and Bland–Altman plots. Results Compared with COMP, mBIR-4 provided more accurate T2 in phantoms and better MWF maps in human brains. Reducing the number of TEs had a negligible effect on MWF map quality, with a regional MWF difference of <0.8%. Regional MWFs obtained by repeated scans showed excellent correlation (R = 0.99), low COV (1.3%–2.4%), and negligible bias within ±1% limits of agreement. On a voxel-wise basis, the agreement remained strong (correlation R = 0.89 ± 0.03, bias = 0.01% ± 0.29%, limits of agreement = [−3.35% ± 0.73%, 3.33% ± 0.61%]). Conclusion Whole brain MWF mapping with adiabatic FAST-T2 is feasible in 4 min and provides good intrasite reproducibility.

We describe the engineering of stable gold nanoparticle (AuNP) bioconjugates for the detection of staphylococcal enterotoxin A (SEA) using localized surface plasmon resonance (LSPR). Two types of AuNP bioconjugates were prepared by covalently attaching anti-SEA antibody (Ab) or SEA to AuNPs. This was achieved by reacting Traut's reagent with lysine residues of both proteins to generate thiol groups that bind to gold atoms on the AuNP surface. These bioconjugates were characterized in-depth by absorption spectroscopy, cryo-transmission electron microscopy, dynamic light scattering, and zeta potential measurements. Their stability over time was assessed after 1 year storage in the refrigerator at 4 °C. Two formats of homogeneous binding assays were set up on the basis of monitoring of LSPR peak shifts resulting from the immunological reaction between the (i) immobilized antibody and free SEA, the direct assay, or (ii) immobilized SEA and free antibody, the competitive assay. In both formats, a correlation between the LSPR band shift and SEA concentration could be established. Though the competitive format did not meet the expected analytical performance, the direct format, the implementation of which was very simple, afforded a specific and sensitive response within a broad dynamic range-nanogram per milliliter to microgram per milliliter. The limit of detection (LOD) of SEA was estimated to equal 5 ng/mL, which was substantially lower than the LOD obtained using a quartz crystal microbalance. Moreover, the analytical performance of AuNP-Ab bioconjugate was preserved after 1 year of storage at 4 °C. Finally, the LSPR biosensor was successfully applied to the detection of SEA in milk samples. The homogeneous nanoplasmonic immunosensor described herein provides an attractive alternative for stable and reliable detection of SEA in the nanogram per milliliter range and offers a promising avenue for rapid, easy to implement, and sensitive biotoxin detection. Sensitive LSPR Biosensing of SEA in buffer and milk using stable AuNP-Antibody bioconjugates Graphical abstract.

To control the ongoing coronavirus disease‐2019 (COVID‐19) pandemic, CoronaVac (Sinovac), an inactivated vaccine, has been granted emergency use authorization by many countries. However, the underlying mechanisms of the inactivated COVID‐19 vaccine‐induced immune response remain unclear, and little is known about its features compared to (Severe acute respiratory syndrome coronavirus 2) SARS‐CoV‐2 infection. Here, we implemented single‐cell RNA sequencing (scRNA‐seq) to profile longitudinally collected PBMCs (peripheral blood mononuclear cells) in six individuals immunized with CoronaVac and compared these to the profiles of COVID‐19 infected patients from a Single Cell Consortium. Both inactivated vaccines and SARS‐CoV‐2 infection altered the proportion of different immune cell types, caused B cell activation and differentiation, and induced the expression of genes associated with antibody production in the plasma. The inactivated vaccine and SARS‐COV‐2 infection also caused alterations in peripheral immune activity such as interferon response, inflammatory cytokine expression, innate immune cell apoptosis and migration, effector T cell exhaustion and cytotoxicity, however, the magnitude of change was greater in COVID‐19 patients, especially those with severe disease, than in immunized individuals. Further analyses revealed a distinct peripheral immune cell phenotype associated with CoronaVac immunization (HLA class II upregulation and IL21R upregulation in naïve B cells) versus SARS‐CoV‐2 infection (HLA class II downregulation and IL21R downregulation in naïve B cells from severe disease individuals). There were also differences in the expression of important genes associated with proinflammatory cytokines and thrombosis. In conclusion, this study provides a single‐cell atlas of the systemic immune response to CoronaVac immunization and revealed distinct immune responses between inactivated vaccines and SARS‐CoV‐2 infection.

Brucella species is responsible for brucellosis in human and animals, which is still of public health, veterinarian, and economic concern in many regions of the world. Here, a novel molecular diagnosis assay, termed loop-mediated isothermal amplification coupled with nanoparticles-based lateral flow biosensor (LAMP-LFB), was developed and validated for simply, rapidly, and reliably detecting all Brucella spp. strains. A set of six primers was designed based on the Brucella -specific gene Bscp31 . The Brucella -LAMP results were visually reported by biosensor within 2 mins. A variety of bacterial strains representing several Brucella species, as well as several Gram-negative and Gram-positive bacterial species were used to determine the analytical sensitivity and specificity of the assay. Optimal LAMP conditions were 63°C for 40 mins, and the assay’s sensitivity was found to be 100 fg of genomic DNA in the pure cultures. No cross-reactions to non- Brucella strains were obtained; thus, analytical specificity of LAMP-LFB assay is of 100%. Using the protocol, 20 mins for rapid DNA preparation followed by isothermal amplification (40 mins) combined with biosensor detection (2 mins) resulted in a total assay time of approximately 65 mins. In the case of 117 whole blood samples, 13 (11.11%) samples were Brucella -positive by LAMP-LFB, and the diagnostic accuracy was 100% when compared to the culture-biotechnical method. In conclusion, Brucella -LAMP-LFB technique developed in this study is a sensitive and specific method to rapidly identify all Brucella spp. strains, and can be applied as a potential diagnostic tool for brucellosis in basic, clinical, and field laboratories.

A rapid and sensitive method to detect cardiac troponin I (cTnI) in human blood is critical to the diagnosis and treatment of acute myocardial infarction (AMI). Here, we describe a simple one-step digital immunoassay for single-molecule detection without washing steps. A sample containing cTnI mixed with detection antibody-conjugated gold nanoparticles (AuNPs) is added to a capture antibody-coated sensor surface and the formation of the antibody-cTnI-antibody sandwich is detected by digitally counting the binding of the individual gold nanoparticles to the sensor surface in real time using a bright-field optical imaging setup together with a differential imaging algorithm. The digital immunoassay detects cTnI in undiluted human plasma, which achieves a detection limit of 5.7 ng/L within a detection time of only 10 min, which meets the requirement of current clinical high-sensitivity troponin assay (∼70 ng/L cutoff). We anticipate that the one-step and real-time digital immunoassay can be applied to the detection of other disease biomarkers in blood.

Posterior decompression surgery was performed on 610 patients (mean age 62 years) with clinically and radiologically defined cervical spondylotic myelopathy (CSM) at Tianjin Medical University General Hospital, between October 2007 and October 2011. After 2-year follow-up, we had a full data sets from 396 patients with normal mood or continued depression during the whole process to be compared. Depression was assessed with the 21-item Beck Depression Inventory. Physical functioning and pain were assessed with the modified Japanese Orthopedic Association (mJOA) scoring system, neck disability index (NDI), and visual analog scale (VAS). There were statistically significant differences from baseline to 2-year follow-up between normal mood (n = 258) and continuous depression (n = 138) groups in mJOA score (6.76 ± 3.12 vs. 1.42 ± 0.56, respectively; p < 0.01), VAS (23.85 ± 20.79 vs. 16.08 ± 19.76, respectively; p < 0.01), and NDI (21.11 ± 11.36 vs. 7.31 ± 2.18; p < 0.05). The adverse consequences of depression are supported by previous findings that patients with depression suffer more unsatisfactory surgery outcome than the patients with normal mood. We emphasize that patients with continuous depression show poorer improvement after posterior decompression in CSM patients with respect to symptom severity, pain intensity, and the disability score than patients without depression at any stage.

Transmembrane exchange of materials is a fundamental process in biology. Molecular dynamics provides a powerful method to investigate in great detail various aspects of the phenomenon, particularly the permeation of small uncharged molecules, which continues to pose a challenge to experimental studies. We will discuss some of the recent simulation studies investigating the role of lipid-mediated and protein-mediated mechanisms in permeation of water and gas molecules across the membrane.

The current outbreak of monkeypox virus (MPXV) has become a public health emergency of international concern that highlights the need for rapid, sensitive MPXV diagnostic assays. Here, we combined isothermal multiple cross displacement amplification (MCDA) with nanoparticle‐based lateral flow biosensor (LFB) to devise a diagnostic test for the diagnosis of MPXV infection (called MPXV‐MCDA‐LFB) and differentiation of West and Central African MPXV isolates. The MPXV‐MCDA‐LFB protocol conducts isothermal MCDA reaction for DNA templates followed by LFB detection of preamplification target sequences. Two MCDA primer sets were designed targeting the D41L and ATI genes of Central and West African MPXV isolates, respectively, and the optimal condition of two MCDA reactions was 64°C for 30 min. The two MCDA reactions were decoded by LFB, which was devised for detecting three targets, including two amplicons yielded from two MCDA reactions and a chromatography control. Thus, the MPXV‐MCDA‐LFB assay could be completed within 50 min including rapid template preparation (15 min), MCDA reaction (30 min) and reporting of result (<5 min). The MPXV‐MCDA‐LFB method is very sensitive and can detect the target genes (D14L and ATI) with as low as five copies of plasmid template per reaction and 12.5 copies of pseudotyped virus in human blood samples. The MPXV‐MCDA‐LFB assay does not cross‐react with non‐MPXV templates, validating its specificity. Therefore, the MPXV‐MCDA‐LFB assay developed here is a useful tool for rapid and reliable diagnosis of MPXV infection.