To explore the propagation characteristics of acoustic waves in heterogeneous acoustic materials, we studied the propagation of acoustic waves in resonant phononic crystals. We identified the ...vibration mechanism of two-dimensional three-component localized resonant phononic crystals. Using the finite element software COMSOL, an acoustic propagation model based on acoustic metamaterials was constructed and the local resonance characteristics of acoustic waves and the original cells were used to simulate multiple acoustic models based on triangular arrays. We found that the planar point-like and linear excitation sources incident from the bottom edge of the triangular array model converge to the focal point at the top corner after being controlled by the model. The low-loss movement effect of the point source could be achieved in a rectangular model with a triangular array. A reversal of the transmission of plane acoustic waves resulted when two or three identical triangular arrays were combined into a parallelogram or a trapezoid. This series of abnormal acoustic phenomena provides new directions for the detection of point sources, low-loss directional transmission of acoustic waves, and acoustic stealth.
In the present study, mechanical alloying (MA) was employed for synthesising non-equilibrium Zn60Zr40 amorphous powders, and then consolidated into amorphous/crystalline Zn60Zr40 alloys using ...selective laser melting (SLM). The results showed that the MA process destabilised the atomic periodicity of Zn and Zr powders and induced crystalline-to-amorphous transformation due to atomic size mismatch and negative heat of mixing. Moreover, the amorphisation trend of as-milled powders was intensified with increasing milling time and attained almost fully amorphous structure after 30 h of milling. During SLM, the ultra-high cooling rate restricted the long-range atomic diffusion of the amorphous powders and enabled successful survival of amorphous phase, leading to amorphous/crystalline Zn60Zr40 alloys. The alloys exhibited a maximum compressive yield strength and microhardness of 160.9 ± 9.1 MPa and 3.73 ± 0.8 GPa, respectively. These findings demonstrated that the developed MA-SLM process might be a promising strategy for the preparation of amorphous/crystalline alloys with superior properties.
To control the HIV/AIDS epidemics in Guangxi Zhuang Autonomous Region in China, Guangxi government launched the 5-year Guangxi AIDS Conquering Project (GACP, Phase I: 2010-2014, Phase II: 2015-2020). ...In the project, three measures are implemented, such as great improvements of the coverage of HIV/AIDS education, promotion of HIV voluntary counseling and testing, and enhancement of antiretroviral treatment. In this paper, we explore the effects of the three measures of GACP by construction of a Susceptible-Infected-Diagnosed-Treated population compartments model and via evaluation of the basic reproduction number derived from the model. A computational framework is developed for estimating the model parameters based on the HIV surveillance data, with application of the Markov-Chain Monte-Carlo method and Nonlinear Least Squares method. By estimating the new infections and evaluating the basic reproduction number, we find that the implementation of the three measures of GACP has a significant effect on controlling the rise of HIV/AIDS cases and the epidemic trend. Compared with HIV voluntary counseling and testing, strengthening HIV/AIDS education and expanding the coverage of antiretroviral treatment show a greater impact on HIV/AIDS epidemic control, which provides a reference project for other provinces with a similar epidemic situation in Guangxi Zhuang Autonomous Region. At the same time, our research fills the current research gap for the evaluation of large-scale AIDS prevention and control projects in developing areas.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A Helmholtz resonator (HR) with an embedded aperture is an effective acoustic metamaterial for noise reduction in the low-frequency range. Its sound absorption property is significantly affected by ...the aperture shape. Sound absorption properties of HRs with the embedded aperture for various tangent sectional shapes were studied by a two-dimensional acoustic finite element simulation. The sequence of resonance frequency from low to high was olive, common trapeziform, reverse trapeziform, dumbbell and rectangle. Meanwhile, those HRs for various cross-sectional shapes were investigated by a three-dimensional acoustic finite element simulation. The sequence of resonance frequency from low to high were round, regular hexagon, square, regular triangle and regular pentagon. Moreover, the reason for these phenomena was analyzed by the distributions of sound pressure, acoustic velocity and temperature. Furthermore, on the basement of the optimum tangent and cross-sectional shape, the sound absorption property of parallel-connection Helmholtz resonators was optimized. The experimental sample with optimal parameters was fabricated, and its average sound absorption coefficient reached 0.7821 in 500-820 Hz with a limited thickness of 30 mm. The research achievements proved the significance of aperture shape, which provided guidance for the development of sound absorbers in the low-frequency range.
•Fault-slip analysis was performed in the Jurassic to Cretaceous Huangshan Basin.•Eight stages of paleostress fields were established in Late Mesozoic to Cenozoic.•Strike-slip and extensional regimes ...alternated to dominate evolution of SE China.•Paleostress fields were related to Paleo-Pacific subduction and India-Asia collision.
Eight paleostress stages are established in the Jurassic-Cretaceous Huangshan Basin based on fault-slip analysis and age estimation. The first six stages correspond to the subduction of the Paleo-Pacific Plate or the northward motion of the Philippine Block along the southeastern active margin of the South China Block: (1) the 169–162Ma strike-slip regime was caused by westward low-angle subduction of the Paleo-Pacific Plate, which resulted in NNE-striking folds and top-to-the west thrusting along the southeastern margin of the Huangshan Basin; (2) the 156–125Ma NW-SE extensional regime was triggered by slab break-off of the Paleo-Pacific Plate. This extension led to Early Cretaceous magmatism, deposition of Early Cretaceous sediments and development of normal faults along the northern boundary of the Huangshan Basin; (3) the 125–107Ma strike-slip regime was induced by the N-S collision between the Philippine and South China blocks. This tectonic event caused the angular unconformity between the Upper and Lower Cretaceous and the inversion of the Early Cretaceous extensional basin; (4) the 105–86Ma WNW-ESE extensional regime resulted from an off-shore arc jump of the subducted Paleo-Pacific Plate. This extension triggered the deposition of the Late Cretaceous Qiyunshan Formation; (5) the 86–80Ma strike-slip regime was induced by high-angle subduction of the Pacific Plate after the off-shore arc jump. This event led to regional uplift and an unconformity at the base of the Late Cretaceous Xiaoyan Formation; (6) the 80–36Ma N-S extensional regime was caused by the extension following the collision between the Philippine and South China blocks, corresponding to the deposition of the Late Cretaceous Xiaoyan Formation. The last two paleostress stages were the consequences of the far-field effect of the India-Asia continent-continent collision to the southwest of the South China Block: (7) the 36–30Ma strike-slip regime was caused by the India-Asia collision. It is recorded by conjugate strike-slip faults and NW-striking thrust faults in the Huangshan Basin; (8) the 28–16Ma ENE-WSW extensional regime resulted from subsequent post-collisional extension. This extension generated NW-striking normal faults in the Huangshan Basin and elsewhere in the eastern margin of Asia. The results of our paleostress inversion support that the Late Mesozoic to Cenozoic tectonic evolution of southeastern China is characterized by alternating strike-slip and extensional regimes.
Vitellogenin (
) is a precursor of yolk proteins in egg-laying vertebrates and invertebrates and plays an important role in vitellogenesis and embryonic development. However, the
family remains ...poorly characterized in
, a major commercial mariculture species found along the coasts of the Yellow and Bohai Seas. In this study, 10
genes from the genomes of
were identified and characterized. Phylogenetic analyses showed that the
genes in crustaceans could be classified into four groups: Astacidea, Brachyra, Penaeidae, and Palaemonidae.
genes were unevenly distributed on the chromosomes of
, and a molecular evolutionary analysis showed that the
genes were primarily constrained by purifying selection during evolution. All putative
proteins were characterized by the presence of three conserved functional domains: a lipoprotein N-terminal domain (LPD_N), a domain of unknown function (DUF1943), and a von Willebrand factor type D domain (vWD). All
genes exhibited higher expression in the female hepatopancreas than in other tissues, and
gene expression during ovarian development suggested that the hepatopancreas is the main synthesis site in
.
,
, and
play major roles in exogenous vitellogenesis, and
also plays a major role in endogenous vitellogenesis. Bilateral ablation of the eyestalk significantly upregulates
mRNA expression in the female hepatopancreas, indicating that the X-organ/sinus gland complex plays an important role in ovarian development, mostly by inducing
synthesis. These results could improve our understanding of the function of multiple
genes in crustaceans and aid future studies on the function of
genes during ovarian development in
.
Elastomers play an irreplaceable role in our society due to their unique properties. Natural rubber is directly obtained from plants and is widely used in tires, shoes, etc. Recently, modified ...natural rubbers are proposed to expand the application of natural rubber. However, these natural rubbers have a limited variety of molecular structures and may not be able to meet ever‐demanding applications. Traditional synthetic elastomers have a variety of molecular structures and their properties are used in various fields, but mainly originate from fossil resources. This review deals with bio‐based elastomers, and more specifically natural rubber and bio‐based synthetic elastomers. Based on reprocessability, bio‐based elastomers can also be divided into bio‐based chemically cross‐linked ones and thermoplastic ones. Compared to traditional fossil‐based elastomers, bio‐based ones may alleviate environmental pollution and promote the sustainable development of the elastomer industry.
In this review, we summarize a brief introduction to the development of bio‐based elastomer derived from biomass resource, which are divided into bio‐based chemical cross‐linked rubbers and thermoplastic elastomers according to their processability. The former mainly describes natural rubbers and bio‐based synthetic elastomers. Meanwhile, the latter mainly presents thermoplastic polyester elastomers (TPEEs), thermoplastic polyurethane elastomers (TPUs), and thermoplastic polyamide elastomers (TPAEs). More importantly, some of bio‐based elastomers have already been implemented for commercial application in society. The synthesis of bio‐based elastomers used sustainable energy could contribute to the low carbon emission and carbon neutrality.
Objective
To explore the relationship between the residual glomerular filtration rate (GFR) on the operated side and the GFR on the contralateral side following partial nephrectomy (PN) in patients ...with localized renal cell carcinoma (RCC).
Materials and methods
Following institutional review board approval, we conducted a retrospective analysis of clinical records from May 2018 to July 2023, involving 118 patients who underwent partial nephrectomy for unilateral localized kidney tumors (T1–T2). Glomerular filtration rate data were assessed using single photon emission computed tomography (
SPECT
)/computed tomography imaging using 9mTc-DTPA (diethylenetriaminepentaacetic acid) renal dynamic imaging. The independent determinants of postoperative renal function or renal function change were determined using linear regression analysis. In addition, the patient's demographic, clinical, and nephrometry characteristics were collected.
Results
A total of 58 patients were finally enrolled. The preoperative and postoperative GFR of bilateral kidneys showed a significant positive correlation. Postoperative GFR of the operated kidney was the independent predictor of GFR of contralateral kidney (
p
= 0.001). Tumor diameter (
p
= 0.036), age (
p
= 0.005), and postoperative GFR of the contralateral kidney (
p
= 0.001) were all independent predictors of postoperative GFR of the operated kidney. ΔGFR1 was the independent predictor of ΔGFR2. Results showed that a more pronounced postoperative decline in GFR on the operated side corresponded to a weaker compensatory capacity of the contralateral-side kidney.
Conclusions
During the course of the surgical procedure, the active endeavor to safeguard the renal function of the operated kidney side holds paramount importance, which yields positive outcomes for postoperative kidney function on the contralateral side, consequently contributing to the overall preservation of renal function.
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