The blasting mechanism underlying drilling and blasting of underwater rocks, as an important component of the engineering blasting technology, has not been systematically studied. Laboratory model ...experiments are expensive and take a long time, while field tests fail to obtain timeous breakage and accumulation effects of underwater blasting, and may even be impossible. Considering this, a model experiment of underwater concrete bench blasting was designed, and the motion of blasted blocks was observed and evaluated with a high-speed camera. Then, numerical simulation was conducted based on Fluent and an engineering discrete element method coupling program complied using the application programming interface. Results show that the blocks form a bulge in the underwater blasting experiment under action of blast waves and expansion in the first period of bubble pulsation. Then, some blocks shrink in the first period of bubble pulsation. As the charge increases, the blast load exerts larger disturbance on the block group, resulting in significant motion of blasted blocks along the vertical direction. At the same time, the horizontal displacement of blasted blocks in the throwing direction increases.
Objectives
To assess whether dual-energy computed tomography (DECT), using conventional computed tomography or magnetic resonance imaging as a reference standard, is sufficiently accurate to ...differentiate intracerebral hemorrhage from contrast extravasation after endovascular thrombectomy for acute ischemic stroke.
Methods
On January 20, 2021, we searched the PubMed Medline, Embase, Web of Science, and Cochrane Library databases. QUADAS-2 was used to assess the risk of bias and applicability. Meta-analyses were performed using a bivariate random-effects model. To explore sources of heterogeneity, meta-regression analyses were performed. Deeks’ funnel plot asymmetry test was used to assess publication bias.
Results
A total of 7 studies (269 patients, 269 focal areas) were included. The pooled mean sensitivity, specificity, and accuracy of DECT in identifying intracerebral hemorrhage from contrast extravasation after mechanical thrombectomy for acute ischemic stroke were 0.77 (95% confidence interval (CI) 0.29 to 0.96), 1 (95% CI 0.86 to 1), and 0.99 (95% CI 0.98 to 1), respectively. This evidence was of moderate certainty due to the risk of bias. Higgin’s
I
-squared for study heterogeneity was observed for the pooled sensitivity (
I
2
= 78.88%) and pooled specificity (
I
2
= 82.12%). Moreover, Deeks’ funnel plot asymmetry test revealed no publication bias (
p
= 0.38).
Conclusion
DECT shows excellent accuracy and specificity in differentiating intracerebral hemorrhage from contrast extravasation after endovascular thrombectomy for acute ischemic stroke. Nevertheless, there was substantial and moderate heterogeneity among the studies. Future large-scale, prospective cohort studies are warranted to validate our findings.
Key Points
•
Dual-energy computed tomography shows excellent accuracy and specificity in differentiating intracerebral hemorrhage from contrast extravasation after endovascular thrombectomy for acute ischemic stroke.
•
Via meta-regression analysis, we found various possible covariates, including the publication date, image analysis, index test time, time of follow-up imaging, and reference standard judgment, that had an important effect on the heterogeneity.
•
There were no concerns regarding applicability in any of the included studies.
The association between the fluctuation in blood pressure (BP) and the early outcomes of patients with subarachnoid hemorrhage (SAH) remains unclear. Our study aimed to evaluate the value of blood ...pressure variability (BPV) for predicting the short-term outcomes of patients with acute spontaneous SAH. We collected data from 303 patients hospitalized for acute spontaneous SAH. BP values were recorded at admission and subsequently every 2 h during the initial 24 h of hospitalization. BPV was determined as the standard deviation (SD), the difference between the maximum and the minimum (ΔBP), the coefficient of variation (CV), and successive variation (SV). The outcome at discharge was assessed according to the Glasgow Outcome Scale (GOS). The association between BPV and the outcome was identified by multivariable analysis. The findings showed that the parameters of systolic BPV were independently associated with the outcome in a graded fashion. The odds ratios (OR) for the highest tertiles were as follows: SD 13.9 (95% confidence interval CI, 4.8-40.4), ΔBP 4.4 (95% CI, 1.6-11.9), CV 16.4 (95% CI, 5.6-48.8), SV 15.8 (95% CI, 5.3-46.9). However, there was no association between a poor outcome and diastolic BPV (all p > 0.05). In conclusion, systolic BPV within the first 24 h after admission was independently associated with the outcomes in SAH patients; the greater the variability was, the worse the outcome.
Alternaria alternata botybirnavirus 1 (AaBRV1) was isolated from a strain of Alternaria alternata, causing watermelon leaf blight in our previous research. The effect of AaBRV1 on the phenotype of ...its host fungus, however, was not determined. In the present study, a novel strain of AaBRV1 was identified in A. tenuissima strain TJ-NH-51S-4, the causal agent of cotton Alternaria leaf spot, and designated as AaBRV1-AT1. A mycovirus AaBRV1-AT1-free strain TJ-NH-51S-4-VF was obtained by protoplast regeneration, which eliminated AaBRV1-AT1 from the mycovirus AaBRV1-AT1-infected strain TJ-NH-51S-4. Colony growth rate, spore production, and virulence of strain TJ-NH-51S-4 were greater than they were in TJ-NH-51S-4-VF, while the sensitivity of strain TJ-NH-51S-4 to difenoconazole, as measured by the EC50, was lower. AaBRV1-AT1 was capable of vertical transmission via asexual spores and horizontal transmission from strain TJ-NH-51S-4 to strain XJ-BZ-5-1hyg (another strain of A. tenuissima) through hyphal contact in pairing cultures. A total of 613 differentially expressed genes (DEGs) were identified in a comparative transcriptome analysis between TJ-NH-51S-4 and TJ-NH-51S-4-VF. Relative to strain TJ-NH-51S-4-VF, the number of up-regulated and down-regulated DEGs in strain TJ-NH-51S-4 was 286 and 327, respectively. Notably, the expression level of one DEG-encoding cytochrome P450 sterol 14α-demethylase and four DEGs encoding siderophore iron transporters were significantly up-regulated. To our knowledge, this is the first documentation of hypervirulence and reduced sensitivity to difenoconazole induced by AaBRV1-AT1 infection in A. tenuissima.
Underwater rock-plug blasting is a special blasting technique for excavating underwater inlets. In the process of rock-plug blasting excavation, the blasting-block movement from the difference in ...water pressure inside and outside the tunnel is one of the key factors for successful construction. Laboratory underwater rock-plug blasting experiments were conducted using small explosive charges, and a high-speed camera was adopted to observe and study block motion. Then, numerical simulations were conducted for the model experiment based on the Fluent and Engineering Discrete Element Method (EDEM) coupling program developed using the user-defined function (UDF) interface to reveal the mechanism underpinning the penetration of underwater rock-plug blasting. The results showed that the process of block motion in underwater rock-plug blasting can be divided into two stages. In the first stage, broken blocks move to two sides along the axis of the rock plug under the blast load. A blasting crater is formed on the downstream end face of the rock plug under the effects of the free face, while the upstream end face is loosened, or blocks are ejected under the influence of the water pressure. In the second stage, blocks flow to the broken-rock pit under the effects of water scouring and gravity, and, finally, the rock plug is penetrated. The larger the head of water and the opening angle of the rock plug are, the better the penetration effect for the rock plug is. The Fluent–EDEM coupling algorithm was in good agreement with the experimental results in terms of the rock-plug blasting effect and the velocity curve of the blocks, indicating that the coupling method had a favorable effect in simulating the interaction of blocks and water during underwater rock-plug blasting. The findings are expected to promote the application and popularization of the rock-plug blasting technique and can provide a reference for rock-plug blasting in water-intake and water-diversion projects.
In this study, a new double-stranded RNA (dsRNA) virus, Alternaria tenuissima partitivirus 1 (AttPV1), was isolated from
Alternaria tenuissima
strain XJ-BZ-2-6, a phytopathogenic fungus infecting ...cotton in China. The genome of AttPV1 comprised three dsRNAs of 1,785 nt (dsRNA1), 1,545 nt (dsRNA2), and 1,537 nt (dsRNA3) in length, the nucleotide sequence of which was determined using reverse transcription polymerase chain reaction, random-primed clones, and RNA-ligase-mediated rapid amplification of cDNA ends. dsRNA1 had a single open reading frame encoding a putative 61.54-kDa RNA-dependent RNA polymerase (RdRp). dsRNA2 and dsRNA3 were predicted to encode putative coat proteins (CPs) of 47.90 kDa and 46.25 kDa, respectively. The RdRp domain shared 63.54-73.17% amino acid sequence identity with members of the genus
Gammapartitivirus
. Phylogenetic trees based on RdRp or CP sequences showed that AttPV1 clustered with members of the genus
Gammapartitivirus
. Hence, these results indicate that AttPV1 is a new gammapartitivirus from
A. tenuissima
.
A new double-stranded RNA (dsRNA) virus named Alternaria alternata botybirnavirus 1 (AaBRV1) was isolated from
Alternaria alternata
strain SD-BZF-19, a phytopathogenic fungus infecting watermelon in ...China. The genome of AaBRV1 consists of two dsRNA segments (dsRNAs 1 and 2), 6,130 and 5,862 bp in size, respectively. The sequence contains two putative open reading frames (ORFs) which encode two polyproteins of 1,874 and 1,784 amino acids, respectively. Nucleotide sequence comparisons revealed that the two ORFs of AaBRV1 have the highest similarity 60.3% and 56.7%, respectively, with dsRNAs 1 and 2 of
Botrytis porri RNA virus 1
(BpRV1). The two polyproteins encoded by dsRNA1 and dsRNA2 shared the highest amino acid identities with the cap-pol fusion protein (60.2%) and hypothetical protein (53.7%) of BpRV1, respectively. AaBRV1 is composed of isometric particles, approximately 35 nm in diameter. Phylogenetic analysis of the RNA dependent RNA polymerase (RdRp) domain of the polyprotein revealed that AaBRV1 clusters together with members of the genus
Botybirnavirus
. These findings support the discovery of a new botybirnavirus in
A. alternata
.
Relatively independent evaluation parameters are selected from many parameters through pedigree clustering.Learning the analytic hierarchy process (ahp) and entropy weight method can determine the ...weight, and at the same time to understand the error of the analytic hierarchy process (ahp) and entropy weight method is large, so the combination of the subjective and objective weight obtained by the two methods, using the improved entropy weight-ahp method to determine the weight. The improved weight calculation method has a clear hierarchical structure, which not only considers the influence of subjective and objective factors, but also makes full use of the weight information in the hierarchical structure. Considering the uncertainty of information, gray relation is adopted to deal with the data, so as to make maintenance rules.
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