AbstractAn improved vacuum preloading method was developed to consolidate clay-slurry fill that is hydraulically placed in seawater for land reclamation. This method adopted both a vacuum and an ...air-pressurizing system. In the vacuum system, a new connector to connect each prefabricated vertical drain (PVD) directly to a horizontal vacuum pipe is used in lieu of a horizontal sand blanket. In the air-pressurizing system, compressed air is injected into the soil to accelerate consolidation. Field pilot tests using both the improved and the existing vacuum preloading systems were carried out at the same site. The testing data showed that better consolidation results were achieved using the improved vacuum preloading method.
To effectively stabilize coarse sand, bentonite was introduced in microbially induced carbonate precipitation (MICP) grouting. Varying concentrations (0, 20, 40, and 80 g/L) of bentonite were added ...to bacterial suspensions (BSs), which were magnetically stirred to form bacterial-bentonite suspensions (BBSs). Then, coarse sand specimens were treated with BBSs and cementation solutions (CSs) to different cementation levels. The results showed that the addition of bentonite could increase the volume fractions of the precipitates consisting of calcium carbonate (CaCO
3
) and bentonite. The permeability decreased exponentially as the volume fraction of precipitates increased. As the active precipitates increased when a lower concentration (e.g., 20 g/L) of bentonite was added to the MICP grouting, the unconfined compressive strength (UCS) was substantially improved. However, detrimental effects were observed for specimens treated with a high concentration of bentonite. These results indicate that the effective concentration of natural clay aggregates used in MICP grouting was different for different engineering applications, e.g., seepage control and strength enhancement. The current work provides an encouraging method of improving the MICP technique.
Homologous recombination (HR) is a crucial pathway for double-stranded DNA break (DSB) repair. During the early stages of HR, the newly generated DSB ends are processed to yield long single-stranded ...DNA (ssDNA) overhangs, which are quickly bound by replication protein A (RPA). RPA is then replaced by the DNA recombinase Rad51, which forms extended helical filaments on the ssDNA. The resulting nucleoprotein filament, known as the presynaptic complex, is responsible for pairing the ssDNA with homologous double-stranded DNA (dsDNA), which serves as the template to guide DSB repair. Here, we use single-molecule imaging to visualize the interplay between human RPA (hRPA) and human RAD51 during presynaptic complex assembly and disassembly. We demonstrate that ssDNA-bound hRPA can undergo facilitated exchange, enabling hRPA to undergo rapid exchange between free and ssDNA-bound states only when free hRPA is present in solution. Our results also indicate that the presence of free hRPA inhibits RAD51 filament nucleation, but has a lesser impact upon filament elongation. This finding suggests that hRPA exerts important regulatory influence over RAD51 and may in turn affect the properties of the assembled RAD51 filament. These experiments provide an important basis for further investigations into the regulation of human presynaptic complex assembly.
Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease that typically leads to respiratory failure and death within 3–5 years of diagnosis. Sub-pleural pulmonary fibrosis is a ...pathological hallmark of IPF. Bleomycin treatment of mice is a an established pulmonary fibrosis model. We recently showed that bleomycin-induced epithelial-mesenchymal transition (EMT) contributes to pleural mesothelial cell (PMC) migration and sub-pleural pulmonary fibrosis. MicroRNA (miRNA) expression has recently been implicated in the pathogenesis of IPF. However, changes in miRNA expression in PMCs and sub-pleural fibrosis have not been reported. Using cultured PMCs and a pulmonary fibrosis animal model, we found that miR-18a-5p was reduced in PMCs treated with bleomycin and that downregulation of miR-18a-5p contributed to EMT of PMCs. Furthermore, we determined that miR-18a-5p binds to the 3′ UTR region of transforming growth factor β receptor II (TGF-βRII) mRNA, and this is associated with reduced TGF-βRII expression and suppression of TGF-β-Smad2/3 signaling. Overexpression of miR-18a-5p prevented bleomycin-induced EMT of PMC and inhibited bleomycin-induced sub-pleural fibrosis in mice. Taken together, our data indicate that downregulated miR-18a-5p mediates sub-pleural pulmonary fibrosis through upregulation of its target, TGF-βRII, and that overexpression of miR-18a-5p might therefore provide a novel approach to the treatment of IPF.
Sub-pleural pulmonary fibrosis is a pathological hallmark of idiopathic pulmonary fibrosis (IPF). Zhang et al. found that downregulated miR-18a-5p mediates sub-pleural pulmonary fibrosis through upregulation of its target, TGF-βRII, suggesting that overexpression of miR-18a-5p might be an approach to the treatment of IPF.
We compared clinical, laboratory, radiological, and outcome features of patients with SARS-CoV-2 infection (COVID-19) with pneumonia, with vs without diarrhea.
We performed a retrospective, ...single-center analysis of 84 patients with SARS-CoV-2 pneumonia in Wuhan Union Hospital, China, from January 19 through February 7, 2020. Cases were confirmed by real-time reverse-transcriptase PCR of nasal and pharyngeal swab specimens for SARS-CoV-2 RNA. Blood samples were analyzed for white blood cell count, lymphocyte count, alanine aminotransferase, creatine kinase, lactate dehydrogenase, D-dimer, C-reactive protein, and in some cases, immunoglobulins, complement, lymphocyte subsets, and cytokines. Virus RNA was detected in stool samples by real-time PCR.
Of the 84 patients with SARS-CoV-2 pneumonia, 26 (31%) had diarrhea. The duration of fever and dyspnea in patients with diarrhea was significantly longer than those without diarrhea (all P < .05). Stool samples from a higher proportion of patients with diarrhea tested positive for virus RNA (69%) than from patients without diarrhea (17%) (P < .001). As of February 19, a lower proportion of patients with diarrhea had a negative result from the latest throat swab for SARS-CoV-2 (77%) than patients without diarrhea (97%) (P = .010), during these patients' hospitalization. Of 76 patients with a negative result from their latest throat swab test during hospitalization, a significantly higher proportion of patients with diarrhea had a positive result from the retest for SARS-CoV-2 in stool (45%) than patients without diarrhea (20%) (P = .039).
At a single center in Wuhan, China, 31% of patients with SARS-CoV-2 pneumonia had diarrhea. A significantly higher proportion of patients with diarrhea have virus RNA in stool than patients without diarrhea. Elimination of SARS-CoV-2 from stool takes longer than elimination from the nose and throat.
The current outbreak of coronavirus disease 2019 (COVID-19) caused by Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Wuhan, Hubei, China, spreads across national and international ...borders.
We prospectively collected medical records of 14 health care workers (HCWs) who were infected with SARS-CoV-2, in neurosurgery department of Wuhan Union Hospital, China.
Among the 14 HCWs, 12 were conformed cases, the other 2 were suspected cases. Most of them were either exposed to the two index patients or infected coworkers, without knowing they were COVID-19 patients. There were 4 male and 10 female infected HCWs in this cohort, whose mean age was 36 years (SD, 6 years). The main symptoms included myalgia or fatigue (100%), fever (86%) and dry cough (71%). On admission, 79% of infected HCWs showed leucopenia and 43% lymphopenia. Reduced complement C3 could be seen in 57% of the infected HCWs and IL-6 was significantly elevated in 86% of them. The proportion of lymphocytes subsets, concentrations of immunoglobulins, complement C4, IL-2, IL-4, IL-10, TNF-α and IFN-γ were within normal range in these 14 infected HCWs. The most frequent findings on pulmonary computed tomographic images were bilateral multifocal ground-glass opacifications (86%).
Human-to-human transmission of COVID-19 pneumonia has occurred among HCWs, and most of these infected HCWs with confirmed COVID-19 are mild cases. Our data suggest that in the epidemic area of COVID-19, stringent and urgent surveillance and infection-control measures should be implemented to protect doctors and nurses from COVID-19 infection.
The objective of the present study was to investigate the presence of interleukin (IL)-27 in pleural effusions and to evaluate the diagnostic significance of pleural IL-27. The concentrations of ...IL-27 were determined in pleural fluids and sera from 68 patients with tuberculous pleural effusion, 63 malignant pleural effusion, 22 infectious pleural effusion, and 21 transudative pleural effusion. Flow cytometry was used to identify which pleural cell types expressed IL-27. It was found that the concentrations of pleural IL-27 in tuberculous group were significantly higher than those in malignant, infectious, and transudative groups, respectively. Pleural CD4(+) T cells, CD8(+) T cells, NK cells, NKT cells, B cells, monocytes, macrophages, and mesothelial cells might be the cell sources for IL-27. IL-27 levels could be used for diagnostic purpose for tuberculous pleural effusion, with the cut off value of 1,007 ng/L, IL-27 had a sensitivity of 92.7% and specificity of 99.1% for differential diagnosing tuberculous pleural effusion from non-tuberculous pleural effusions. Therefore, compared to non-tuberculous pleural effusions, IL-27 appeared to be increased in tuberculous pleural effusion. IL-27 in pleural fluid is a sensitive and specific biomarker for the differential diagnosing tuberculous pleural effusion from pleural effusions with the other causes.
The tumour suppressor complex BRCA1-BARD1 functions in the repair of DNA double-stranded breaks by homologous recombination. During this process, BRCA1-BARD1 facilitates the nucleolytic resection of ...DNA ends to generate a single-stranded template for the recruitment of another tumour suppressor complex, BRCA2-PALB2, and the recombinase RAD51. Here, by examining purified wild-type and mutant BRCA1-BARD1, we show that both BRCA1 and BARD1 bind DNA and interact with RAD51, and that BRCA1-BARD1 enhances the recombinase activity of RAD51. Mechanistically, BRCA1-BARD1 promotes the assembly of the synaptic complex, an essential intermediate in RAD51-mediated DNA joint formation. We provide evidence that BRCA1 and BARD1 are indispensable for RAD51 stimulation. Notably, BRCA1-BARD1 mutants with weakened RAD51 interactions show compromised DNA joint formation and impaired mediation of homologous recombination and DNA repair in cells. Our results identify a late role of BRCA1-BARD1 in homologous recombination, an attribute of the tumour suppressor complex that could be targeted in cancer therapy.
Central to homologous recombination in eukaryotes is the RAD51 recombinase, which forms helical nucleoprotein filaments on single-stranded DNA (ssDNA) and catalyzes strand invasion with homologous ...duplex DNA. Various regulatory proteins assist this reaction including the RAD51 paralogs. We recently discovered that a RAD51 paralog complex from C. elegans, RFS-1/RIP-1, functions predominantly downstream of filament assembly by binding and remodeling RAD-51-ssDNA filaments to a conformation more proficient for strand exchange. Here, we demonstrate that RFS-1/RIP-1 acts by shutting down RAD-51 dissociation from ssDNA. Using stopped-flow experiments, we show that RFS-1/RIP-1 confers this dramatic stabilization by capping the 5′ end of RAD-51-ssDNA filaments. Filament end capping propagates a stabilizing effect with a 5′→3′ polarity approximately 40 nucleotides along individual filaments. Finally, we discover that filament capping and stabilization are dependent on nucleotide binding, but not hydrolysis by RFS-1/RIP-1. These data define the mechanism of RAD51 filament remodeling by RAD51 paralogs.
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•A nematode RAD51 paralog complex binds the 5′ end of RAD51 pre-synaptic filaments•Filament binding drives pre-synaptic complex remodeling with 5′→3′ polarity•Pre-synaptic complex remodeling propagates up to 40 nucleotides from the 5′ end•Filament binding is dependent on a nucleotide co-factor, but not ATP hydrolysis
RAD51 paralogs promote homologous recombination by remodeling RAD51-ssDNA filaments. Here, Taylor et al. demonstrate that RAD51 paralogs mediate remodeling by specifically binding the 5′ end of RAD51 filaments in a nucleotide-dependent manner. This propagates a stabilizing effect with 5′→3′ polarity distal to their binding site, slowing RAD51 dissociation from DNA.
The current detoxification options of uranium, a toxic radioactive heavy metal, have obvious side effects. Polygonatum kingianum (PK), a natural product with the function of antioxidant, may be ...effective in detoxification and prevention of uranium-induced nephrotoxicity. Here, we studied the protective effects of PK polysaccharides (PKP) and aqueous extract (PKAE) on uranium-induced toxicity in human kidney (HK-2) cells. First, the physicochemical properties of PKP and PKAE were characterized. Assays on cultured cells demonstrated that pretreatment with PKP and PKAE significantly increased metabolic activity, relieved morphological impairments, and alleviated apoptosis. The impairments caused by uranium exposure were ameliorated (mitochondrial membrane potential and ATP level increased while reactive oxygen species decreased). Molecular mechanistic studies revealed that PKP and PKAE alleviated uranium-induced cytotoxicity by regulating mitochondria-mediated apoptosis and the GSK-3β/Fyn/Nrf2 pathway. Collectively, our data support the preventive and therapeutic applications of PKP and PKAE for uranium poisoning.
The proposed mechanism by which PKP and PKAE alleviate uranium-induced cytotoxicity. PKP and PKAE act as antioxidants, activating the GSK-3β/Fyn/Nrf2 pathway by reducing ROS level, thereby alleviating oxidative damages. In addition, PKP and PKAE serve as mitochondrial modulators to inhibit mitochondria-mediated apoptosis by conserving mitochondrial functions (maintaining MMP and ATP level, suppressing ROS production). This figure was prepared using BioRender (Toronto, CA). sMaf: small musculoaponeurotic fibrosarcoma; ARE: antioxidant response elements. Display omitted
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