Rocks in underground projects at great depth, which are under high static stresses, may be subjected to dynamic disturbance at the same time. In our previous work (Li et al. Int J Rock Mech Min Sci ...45(5):739–748,
2008
), the dynamic compressive behaviour of pre-stressed rocks was investigated using coupled-load equipment. The current work is devoted to the investigation of the dynamic tensile behaviour of granite rocks under coupled loads using the Brazilian disc (BD) method with the aid of a high-speed camera. Through wave analyses, stress measurements and crack photography, the fundamental problems of BD tests, such as stress equilibrium and crack initiation, were investigated by the consideration of different loading stresses with abruptly or slowly rising stress waves. The specially shaped striker method was used for the coupled-load test; this generates a slowly rising stress wave, which allows gradual stress accumulation in the specimen, whilst maintaining the load at both ends of the specimen in an equilibrium state. The test results showed that the tensile strength of the granite under coupled loads decreases with increases in the static pre-stresses, which might lead to modifications of the blasting design or support design in deep underground projects. Furthermore, the failure patterns of specimens under coupled loads have been investigated.
The low-frequency line spectrum of the radiated noise signals of hydroacoustic targets contains features describing the intrinsic properties of the target that make the target susceptible to ...exposure. In order to extract the line spectral features of underwater acoustic targets, a method combining image processing and a deep autoencoder network (DAE) is proposed in this paper to enhance the low-frequency weak line spectrum of underwater targets in an extremely low signal-to-noise ratio environment based on the measured data of large underwater vehicles. A Gauss–Bernoulli restricted Boltzmann machine (G–BRBM) for real-value signal processing was designed and programmed by introducing a greedy algorithm. On this basis, the encoding and decoding mechanism of the DAE network was used to eliminate interference from environmental noise. The weak line spectrum features were effectively enhanced and extracted under an extremely low signal-to-noise ratio of 10–300 Hz, after which the reconstruction results of the line spectrum features were obtained. Data from large underwater vehicles detected by far-field sonar arrays were processed and the results show that the method proposed in this paper was able to adaptively enhance the line spectrum in a data-driven manner. The DAE method was able to achieve more than double the extractable line spectral density in the frequency band of 10–300 Hz. Compared with the traditional feature enhancement extraction method, the DAE method has certain advantages for the extraction of weak line spectra.
Underwater acoustic target recognition methods based on time-frequency analysis have shortcomings, such as missing information on target characteristics and having a large computation volume, which ...leads to difficulties in improving the accuracy and immediacy of the target recognition system. In this paper, an underwater acoustic target recognition model based on a deep residual attention convolutional neural network called DRACNN is proposed, whose input is the time-domain signal of the underwater acoustic targets radiated noise. In this model, convolutional blocks with attention to the mechanisms are used to focus on and extract deep features of the target, and residual networks are used to improve the stability of the network training. On the full ShipsEar dataset, the recognition accuracy of the DRACNN model is 97.1%, which is 2.2% higher than the resnet-18 model with an approximately equal number of parameters as this model. With similar recognition accuracies, the DRACNN model parameters are 1/36th and 1/10th of the AResNet model and UTAR-Transformer model, respectively, and the floating-point operations are 1/292nd and 1/46th of the two models, respectively. Finally, the DRACNN model pre-trained on the ShipsEar dataset was migrated to the DeepShip dataset and achieved recognition accuracy of 89.2%. The experimental results illustrate that the DRACNN model has excellent generalization ability and is suitable for a micro-UATR system.
Background:
This study assessed the effects of esmolol injection in patients with in-hospital cardiac arrest (IHCA) with refractory ventricular fibrillation (VF)/pulseless ventricular tachycardia ...(pVT).
Methods:
From January 2018 to December 2021, 29 patients with IHCA with refractory shockable rhythm were retrospectively reviewed. Esmolol was administered after advanced cardiovascular life support (ACLS)-directed procedures, and outcomes were assessed.
Results:
Among the 29 cases, the rates of sustained return of spontaneous circulation (ROSC), 24-h ROSC, and 72-h ROSC were 79%, 62%, and 59%, respectively. Of those patients, 59% ultimately survived to discharge. Four patients with cardiac insufficiency died. The duration from CA to esmolol infusion was significantly shorter for patients in the survival group (SG) than for patients in the dead group (DG) (12 min, IQR: 8.5–19.5 vs. 23.5 min, IQR: 14.4–27 min;
p
= 0.013). Of those patients, 76% (22 of 29) started esmolol administration after the second dose of amiodarone. No significant difference was observed in the survival rate between this group and groups administered an esmolol bolus simultaneously or before the second dose of amiodarone (43% vs. 64%,
p
= 0.403). Of those patients, 31% (9 of 29) were administered an esmolol bolus for defibrillation attempts ≤ 5, while the remaining 69% of patients received an esmolol injection after the fifth defibrillation attempt. No significant differences were observed in the rates of ≥ 24-h ROSC (67% vs. 60%,
p
= 0.73), ≥ 72-h ROSC (67% vs. 55%,
p
= 0.56), and survival to hospital discharge (67% vs. 55%,
p
= 0.56) between the groups administered an esmolol bolus for defibrillation attempts ≤ 5 and defibrillation attempts > 5.
Conclusion:
IHCA patients with refractory shockable rhythms receiving esmolol bolus exhibited a high chance of sustained ROSC and survival to hospital discharge. Patients with end-stage heart failure tended to have attenuated benefits from beta-blockers. Further large-scale, prospective studies are necessary to determine the effects of esmolol in patients with IHCA with refractory shockable rhythms.
(1) Background: The early screening strategy for type A acute aortic syndrome (A-AAS) patients has always been challenging. (2) Methods: From September 2020-31 March 2022, 179 consecutive patients ...with suspected A-AAS were retrospectively reviewed. We assessed the diagnostic value of the use of handheld echocardiographic devices (PHHEs) by emergency medicine (EM) residents either alone or in combination with serum acidic calponin in this patient group. (3) Results: The direct sign of PHHE had a specificity (SP) of 97.7%. The sign of ascending aortic dilatation showed SE = 77.6%, SP = 68.5%, PPV = 48.1% and NPV = 89%. SE, SP, PPV and NPV of a positive PHHE direct sign were 55.6%, 100%, 100% and 71.4% in 19 hypotension/shock patients with suspected A-AAS, respectively. The area under curve (AUC) of acidic calponin combined with an ascending aorta diameter >40 mm was 0.927, with an SE and SP of 83.7% and 89.2%, respectively. These two combined indicators significantly improved the diagnostic efficiency of A-AAS compared with either of them alone (
0.017; standard error 0.016, Z value 2.39;
0.001, standard error 0.028, Z value 3.29). (4) Conclusion: EM resident-performed PHHE was highly indicative of A-AAS in patients presenting with shock or hypotension. An ascending aorta diameter > 40 mm combined with acidic calponin demonstrated acceptable diagnostic accuracy as a rapid first-line triage tool to identify patients with suspected A-AAS.
As an important parameter in application of the Statistical Energy Analysis (SEA), loss factor can measure damping characteristics of a system and determine the ability of vibration energy ...dissipation. First, the experimental models of steel plate structures are established. And then, the loss factor test is carried out based on transient state decay method. Finally, the variation characteristics of loss factor with medium, thickness and size of structures are explored. The results show that: (1) The loss factor of steel plates has the characteristics that larger at low frequency and small at high frequency, it decreases gradually with the increase of frequency. (2) For the same structure, the loss factor tested in water is greater than the loss factor tested in air. (3) The loss factor increases with the raise of thickness of plates when its cross-sectional dimension is constant.
Onomatopoeic terms in English & Chinese, though both imitative of natural sounds, differ markedly in parts of speech & syntactic functions due to the great morphological & structural differences ...between the two languages. In English, they function as subjects, objects, or predicates, & belong to noun or verb classes, while in Chinese, they function mostly as adverbials, attributes, or complements, & display features of adjectives, notwithstanding uncertainty as to their part of speech. Based on the comparisons, the paper searches for the proper transference of their syntactic functions in the course of translation between English & Chinese. 6 References. Adapted from the source document
National & cultural differences in synesthetic words are examined based on universal physiological characteristics. First, there are differences regarding the associative network: although the ...physiology of synesthesia involves an unconditioned reflex, the same external stimulus may have different cultural associations for different nations. Second, Eastern & Western languages differ in their word formation patterns for synesthetic terms, with the former (eg, Chinese) using compounding & the latter mostly utilizing semantic transfer. 25 References. Adapted from the source document
Offers a comparative study of euphemisms in English & Chinese from the perspective of religion. It is noted that a language taboo is characteristic of religion as well as class differences; however, ...English displays more of the former & Chinese the latter. Different influences on the growth & change of euphemisms are also shown to derive from the religious system, which is monistic for English-speaking peoples but pluralistic for the Chinese. 5 References. Adapted from the source document
The current research was aimed at probing into the role of long noncoding RNA (lncRNA) PVT1 in the pathogenesis of glioma and the regulatory mechanism of PVT1/miR-128-3p/
GREM1
network in glioma via ...regulation of the bone morphogenetic protein (BMP) signaling pathway. Microarray analysis was used for preliminary screening for candidate lncRNAs and mRNAs in glioma tissues. Real-time quantitative polymerase chain reaction, Western blot, MTT assay, flow cytometry, migration and invasion assays, and xenograft tumor model were utilized to examine the influence of the lncRNA PVT1/miR-128-3p/
GREM1
network on the biological functions of glioma cells. Luciferase assay and RNA-binding protein immunoprecipitation assay were used to validate the miR-128-3p-target relationships with lncRNA PVT1 or
GREM1.
In addition, the impact of
GREM1
on BMP signaling pathway downstream proteins BMP2 and BMP4 was detected via Western blot. LncRNA PVT1 was highly expressed in human glioma tissues and significantly associated with WHO grade (I–II
vs
III–IV;
p
< 0.05). There existed a regulatory relationship between lncRNA PVT1 and miR-128-3p as well as that between miR-128-3p and
GREM1
. MiR-128-3p was downregulated, whereas
GREM1
was upregulated in glioma tissues in comparison with para-carcinoma tissues. Overexpression of
GREM1
promoted the proliferation and metastatic potential of glioma cells, whereas miR-128-3p mimics inhibited the glioma cell activity through targeting
GREM1.
Furthermore, lncRNA PVT1 acted as a sponge of miR-128-3p and, thus, influenced the BMP signaling pathway downstream proteins BMP2 and BMP4 through regulating
GREM1
. LncRNA PVT1 modulated
GREM1
and BMP downstream signaling proteins through sponging miR-128-3p, thereby promoting tumorigenesis and progression of glioma.
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