Magnetic Ion-Imprinted Materials for Selective Adsorption of Cr(VI): Adsorption Behavior and Mechanism Study.

With the increase of hexavalent Cr(VI) wastewater discharged from industrial production, it seriously pollutes water bodies and poses a risk to human health. Adsorption is used as an effective means to treat Cr(VI), but its effectiveness is affected by pH, and the adsorption performance decreases when acidity is strong. Furthermore, research on the mechanism of Cr(VI) adsorption using DFT calculations needs to be developed. This study focuses on the development of magnetically responsive core-shell nano-ion imprinted materials (Fe3O4@GO@IIP) through magnetic separation and surface imprinting techniques. Characterization techniques including FT-IR, XRD, and EDS confirmed the core-shell nanostructure of Fe3O4@GO@IIP. Batch adsorption experiments and model simulations demonstrated the exceptional adsorption capacity of Fe3O4@GO@IIP for Cr(VI) in strongly acidic solutions (pH = 1), reaching a maximum of 89.18 mg/g. The adsorption mechanism was elucidated through XPS and DFT calculations, revealing that Fe3O4@GO@IIP operates through electrostatic interactions and chemical adsorption, with charge transfer dynamics quantified during the process. This research provides new insights for addressing Cr(VI) treatment in highly acidic environments.

Comparative transcriptome analysis provides insights into molecular pathway and genes associated with head-type formation and phenotypic divergence in Chinese cabbage.

Background: The heading type of Chinese cabbage is a significant commercial trait with high economic value. At present, research on the phenotypic divergence and formation mechanism of heading type is limited. Results: Through comparative-transcriptome analysis, the formation and phenotypic divergence mechanism of the leafy head of diploid overlapping type cabbage, diploid outward-curling type cabbage, tetraploid overlapping type cabbage, and tetraploid outward-curling type cabbage were systematically and comprehensively investigated, and the phenotype-specific genes of four varieties were revealed. These phenotype-specific differentially expressed genes (DEGs) were considered crucial for cabbage heading type through WGCNA. Some transcription factors have been predicted as significant genes for phenotypic divergence, including the members of the bHLH, AP2/ERF-ERF, WRKY, MYB, NAC, and C2CH2 families. Phytohormone-related genes, including abscisic acid/auxin hormone, may play an important role in the phenotypic divergence of head type in cabbage. Conclusion: Comparative-transcriptome analysis supports a role for phytohormone-related genes and some transcription factors in head-type formation and divergence for four cultivars. These findings increase our understanding of the molecular basis for pattern formation and divergence of the leafy heads of Chinese cabbage and will contribute to developing more desirable leafy head patterns.

Comparative Study on Laser Welding Thick-Walled TC4 Titanium Alloy with Flux-Cored Wire and Cable Wire.

In the welding process of thick-walled titanium alloys, the selection of the wire type is one of the critical factors affecting the welding quality. In this paper, flux-cored and cable wires were used as filler materials in the welding of thick-walled titanium alloys. The macrostructure, microstructure, texture, and grain size of both welded joints were compared by employing an optical microscope (OM), scanning electron microscope (SEM), and transmission electron microscope (TEM), and the tensile and impact properties were also evaluated. The comparison result showed that the fusion zone microstructure of both welded joints was dominated by a basketweave structure composed of interwoven acicular α' martensite, whereas the microstructure of flux-cored wire welded joints was finer, and the degree of anisotropy was low. The strength of both welded joints was higher than that of the base metal, ensuring that fracture occurred in the base metal area during tension. The Charpy impact energy of the flux-cored wire welded joint was 16.7% higher than that of the cable wire welded joint, indicating that the welded joint obtained with the flux-cored wire performed better in the welding process of thick-walled titanium alloys.

Gelatinase-responsive photonic crystal membrane for pathogenic bacteria detection and application in vitro health diagnosis.

Selective identification and rapid detection for multiple pathogenic bacteria are important to prevent bacterial infection. Herein, gelatinase-responsive photonic crystal membrane (PCM) is reported as rapid, selective and direct detection platform for multiple pathogenic bacteria. PCMs exhibit angle-independent structural color, and reflection spectra has negligible change after irradiation and storage under different temperature. The ultra-thin response layer makes shorter detection time (30 min) than the reported gelatin-based photonic crystal detection platform (10-12 h). There is obvious positive correlation between reflection spectra change and gelatinase concentration, even if the gelatinase was as low as 4.8 pM. PCM has high stability against multiple interferers, which are beneficial to improve the detection accuracy and reliability. PCM also show "selective" ability to identify typical pathogens from atypical pathogens through specific response to gelatinase, and good selectivity gives PCM direct detection ability without pretreatment. PCM could detect the pathogens bacteria concentration range spanning 7 orders of magnitude from 10 to 107 CFU/mL, and the relative error between gold standard method and the new platform is less than 10%. Furthermore, PCM's in vitro health diagnosis ability was proved by detecting pathogenic bacteria in artificial wound fluid and urine. All the results show that PCM is well promising platform for selective identifying and rapid detecting pathogenic bacteria in vitro diagnosis.

A Cholesky-based sparse covariance estimation with an application to genes data.

The modified Cholesky decomposition (MCD) is a powerful tool for estimating a covariance matrix. The regularization can be conveniently imposed on the linear regressions to encourage the sparsity in the estimated covariance matrix to accommodate the high-dimensional data. In this paper, we propose a Cholesky-based sparse ensemble estimate for covariance matrix by averaging a set of Cholesky factor estimates obtained from multiple variable orderings used in the MCD. The sparse estimation is enabled by encouraging the sparsity in the Cholesky factor. The theoretical consistent property is established under some regular conditions. The merits of the proposed method are illustrated through simulation and a maize genes data set.

A Cholesky-based estimation for large-dimensional covariance matrices.

This paper develops a new method to estimate a large-dimensional covariance matrix when the variables have no natural ordering among themselves. The modified Cholesky decomposition technique is used to provide a set of estimates of the covariance matrix under multiple orderings of variables. The proposed estimator is in the form of a linear combination of these available estimates and the identity matrix. It is positive definite and applicable in large dimensions. The merits of the proposed estimator are demonstrated through the numerical study and a real data example by comparison with several existing methods.

Extracting multivalent detachment rates from heterogeneous nanoparticle populations.

Nanoparticles can form multiple bonds with target surfaces, thereby increasing adhesion strength and internalization rate into cells. This property has helped to drive interest in nanoparticles as delivery vehicles for drugs and imaging agents, but significant gaps in our understanding of multivalent adhesion make it difficult to control and optimize binding dynamics. In previous work, we experimentally observed that multivalent nanoparticle adhesion can exhibit a time-dependent detachment rate. However, simulations later indicated that the underlying cause was variability in the number of bonds that formed between individual nanoparticles within the population. Here, we use this insight to develop a simple model to isolate a series of constant detachment rates from such heterogeneous populations. Using simulations of experimental data to train the model, we first classified nanoparticles within a given population based on the most likely equilibrium bond number, which we termed the bond potential. We then assumed that each bond potential category would follow standard first-order kinetics with constant detachment rates. Model results matched the population binding data, but only if we further divided each bond potential category into two sub-components, the second of which did not detach. We then utilized bonding rates from the simulation to estimate detachment rates for the second, slower detaching sub-component. These results confirm our hypothesis that nanoparticle populations can be sub-divided based on bond potential, each of which could be characterized by a constant detachment rate. Finally, we established relationships between the new heterogeneous population detachment model and a time-dependent, empirical detachment model that we developed in previous work. This could make it possible to determine bond potential distributions directly from experimental data without computationally costly simulations, which will be explored in future work.

Long nonding RNA UCA1 regulates neural stem cell differentiation by controlling miR-1/Hes1 expression.

Neural stem cells are able to self-renew and generate glial and neuronal lineages. Neural stem cell may serve as therapeutic method for neurological disorders including spinal cord injuries, Parkinson's disease, Huntington's disease and Alzheimer's disease. Long noncoding RNAs (lncRNAs) are longer than 200 nucleotides with limited protein-coding capacity. Recent studies have demonstreated that lncRNAs play an important role in several cellular processes including cell differentiation, cell development, proliferation, apoptosis, invasion and migration. However, the role of lncRNA human urothelial carcinoma associated 1 (UCA1) in the development of neural stem cells remains unknown. In this study, we showed that the expression of UCA1 was upregulated in the neural stem cell in a time-dependent manner. Knockdown of UCA1 suppressed the neural stem cell proliferation. Inhibition of UCA1 decreased the expression of nestin and the formation of neurosphere. Moreover, knockdown of UCA1 suppressed the neural stem cell differentiation to astrocyte and promoted the neural stem cell differentiation to neuron. Furthermore, we demonstrated that knockdown of UCA1 increased the expression of miR-1 in the neural stem cell and suppressed the expresion of Hes1, which is one target gene of miR-1. In addition, ectopic expression of Hes1 could impair siUCA1-induced neural stem cells proliferation. Overexpression of Hes1 suppressed siUCA1-induced ß-tubulin expression and promoted siUCA1-inhibited GFAP expression in the neural stem cell. These results suggested that UCA1 regulated the neural stem cell proliferation and differentiation through regulating Hes1 expression.

Adaptive group bridge estimation for high-dimensional partially linear models.

This paper studies group selection for the partially linear model with a diverging number of parameters. We propose an adaptive group bridge method and study the consistency, convergence rate and asymptotic distribution of the global adaptive group bridge estimator under regularity conditions. Simulation studies and a real example show the finite sample performance of our method.

Evolution of Multivalent Nanoparticle Adhesion via Specific Molecular Interactions.

The targeted delivery of nanoparticle carriers holds tremendous potential to transform the detection and treatment of diseases. A major attribute of nanoparticles is the ability to form multiple bonds with target cells, which greatly improves the adhesion strength. However, the multivalent binding of nanoparticles is still poorly understood, particularly from a dynamic perspective. In previous experimental work, we studied the kinetics of nanoparticle adhesion and found that the rate of detachment decreased over time. Here, we have applied the adhesive dynamics simulation framework to investigate binding dynamics between an antibody-conjugated, 200-nm-diameter sphere and an ICAM-1-coated surface on the scale of individual bonds. We found that nano adhesive dynamics (NAD) simulations could replicate the time-varying nanoparticle detachment behavior that we observed in experiments. As expected, this behavior correlated with a steady increase in mean bond number with time, but this was attributed to bond accumulation only during the first second that nanoparticles were bound. Longer-term increases in bond number instead were manifested from nanoparticle detachment serving as a selection mechanism to eliminate nanoparticles that had randomly been confined to lower bond valencies. Thus, time-dependent nanoparticle detachment reflects an evolution of the remaining nanoparticle population toward higher overall bond valency. We also found that NAD simulations precisely matched experiments whenever mechanical force loads on bonds were high enough to directly induce rupture. These mechanical forces were in excess of 300 pN and primarily arose from the Brownian motion of the nanoparticle, but we also identified a valency-dependent contribution from bonds pulling on each other. In summary, we have achieved excellent kinetic consistency between NAD simulations and experiments, which has revealed new insights into the dynamics and biophysics of multivalent nanoparticle adhesion. In future work, we will leverage the simulation as a design tool for optimizing targeted nanoparticle agents.

Maturation of Fibrinolytic Bacillopeptidase F Involves both Hetero- and Autocatalytic Processes.

Bacillopeptidase F (Bpr) is a fibrinolytic serine protease produced by Bacillus subtilis. Its precursor is composed of a signal peptide, an N-terminal propeptide, a catalytic domain, and a long C-terminal extension (CTE). Several active forms of Bpr have been previously reported, but little is known about the maturation of this enzyme. Here, a gene encoding a Bpr (BprL) was cloned from B. subtilis LZW and expressed in B. subtilis WB700, and three fibrinolytic mature forms with apparent molecular masses of 45, 75, and 85 kDa were identified in the culture supernatant. After treatment with urea, the 75-kDa mature form had the same molecular mass as the 85-kDa mature form, from which we infer that they adopt different conformations. Mutational analysis revealed that while the 85-kDa mature form is generated via heterocatalytic processing of a BprL proform by an unidentified protease of B. subtilis, the production of the 75- and 45-kDa mature forms involves both hetero- and autocatalytic events. From in vitro analysis of BprL and its sequential C-terminal truncation variants, it appears that partial removal of the CTE is required for the initiation of autoprocessing of the N-terminal propeptide, which is composed of a core domain (N*) and a 15-residue linker peptide, thereby yielding the 45-kDa mature form. These data suggest that the differential processing of BprL, either heterocatalytically or autocatalytically, leads to the formation of multiple mature forms with different molecular masses or conformations.

High-resolution Magnetic Resonance Imaging of Moyamoya Disease.

OBJECTIVE: To introduce the imaging characteristics of moyamoya disease (MMD) using high-resolution magnetic resonance imaging (HR-MRI) and to discuss the role of HR-MRI in differentiating MMD from other intracranial artery diseases, especially intracranial atherosclerotic disease (ICAD). DATA SOURCES: This review was based on the data in articles published between 2005 and 2015, which were obtained from PubMed. The keywords included HR-MRI, MMD, ICAD, and intracranial artery diseases. STUDY SELECTION: Articles related to HR-MRI for MMD or other intracranial artery diseases were selected for review. RESULTS: There are differences between the characteristic patterns of HR-MRI in MMD and ICAD. MMD is associated with inward remodeling, smaller outer diameters, concentric occlusive lesions and homogeneous signal intensity, while ICAD is more likely to be associated with outward remodeling, normal outer diameters, eccentric occlusive lesions, and heterogeneous signal intensity. Other intracranial artery diseases, such as dissection and vasculitis, also have distinctive characteristics in HR-MRI. HR-MRI may become a useful tool for the differential diagnosis of MMD in the future. CONCLUSIONS: HR-MRI of MMD provides a more in-depth understanding of MMD, and it is helpful in evaluating pathological changes in the vessel wall and in differentiating MMD from other intracranial artery steno-occlusive diseases, particularly ICAD.

Atrazine-induced apoptosis of splenocytes in BALB/C mice.

BACKGROUND: Atrazine (2-chloro-4-ethytlamino-6-isopropylamine-1,3,5-triazine; ATR), is the most commonly applied broad-spectrum herbicide in the world. Unintentional overspray of ATR poses an immune function health hazard. The biomolecular mechanisms responsible for ATR-induced immunotoxicity, however, are little understood. This study presents on our investigation into the apoptosis of splenocytes in mice exposed to ATR as we explore possible immunotoxic mechanisms. METHODS: Oral doses of ATR were administered to BALB/C mice for 21 days. The histopathology, lymphocyte apoptosis and the expression of apoptosis-related proteins from the Fas/Fas ligand (FasL) apoptotic pathway were examined from spleen samples. RESULTS: Mice administered ATR exhibited a significant decrease in spleen and thymus weight. Electron microscope histology of ultrathin sections of spleen revealed degenerative micromorphology indicative of apoptosis of splenocytes. Flow cytometry revealed that the percentage of apoptotic lymphocytes increased in a dose-dependent manner after ATR treatment. Western blots identified increased expression of Fas, FasL and active caspase-3 proteins in the treatment groups. CONCLUSIONS: ATR is capable of inducing splenocytic apoptosis mediated by the Fas/FasL pathway in mice, which could be the potential mechanism underlying the immunotoxicity of ATR.

[Immunotoxic effect of herbicide simazine exposure in BALB/c mice].

OBJECTIVE: To examine the effect of simazine on selected immune parameters in BALB/c mice. METHODS: Simazine (90, 200, 400 mg/kg) was administrered by oral gavage for 21 days in adult BALB/c mice. The negative control group unith distilled water and positive control group administered with cyclophosphamide in abdominal cavity were also established. After the last simazine dose, the mice were sacrificed, and blood, spleens, and thymuses were collected and processed for detection. The relative weight of spleen and thymus was calculated. The rate of T cell in spleen and the concentration of IL-2, IL-4, IgG and IgM were detected by ELISA. RESULTS: The weights of mice were decreased in 200 mg/kg and 400 mg/kg simazine groups. Thymus and spleen weights were decreased in 200 mg/kg and 400 mg/kg simazine groups compared with the negative control group. The concentration of IL-2, IL-4, IgG and IgM in serum of 200 mg/kg group were (108.50 +/- 3.20) pg/ml, (36.54 +/- 3.36) pg/ml, (46.25 +/- 7.41) µg/ml, (17.58 +/- 2.23) µg/ml respectively;The concentration of IL-2, IL-4, IgG and IgM in serum of 400 mg/kg group were (85.70 +/- 4.00) pg/ml, (35.92 +/- 2.29) pg/ml, (40.08 +/- 6.80) µg/ml, (11.92 +/- 3.23) µg/ml respectively (P < 0.05 or P < 0.01). These results were decreased significantly compared with negative group. CONCLUSION: Simazine can inhibit the cellular immune function and the humoral immune function.

[Effect of Atrazine on the content of calcium and expression of calmodulin in splenocytes of mice].

OBJECTIVE: To investigate the effects of Atrazine on the concentration of intracellular calcium ([Ca2+]i) and the expression of calmodulin (CaM) in splenocytes. METHODS: The mice were divided into 5 groups, and were lavaged the doses of 100, 200 and 400 mg/kg Atrazine respectively. The mice were administrated Atrazine for 3 weeks. The Ca2+ concentrations in serum were detected by atomic absorption spectrophotometer. The [Ca2+]i in splenocytes were determined by fluorospectrophotometer. The expressions of CaM were detected by western blot analysis. RESULTS: The changes of the Ca2+ concentrations of serum in treatment groups were not observed. The intracellular calcium concentrations and CaM expressions in treatment groups were significantly increased and decreased compared with the control group. CONCLUSION: Atrazine could induced the increase of calcium concentration and the depression of the expression of CaM in splenocytes of mice.