Theoretical model of membrane acoustic absorber with compact magnet.

The membrane sound absorber (MSA) with a compact magnet has exhibited excellent tunable properties for low-frequency sound absorption. To further clarify its acoustic properties, this paper presents a theoretical model based on a multi-mechanism coupling impedance method. The model predicts the absorption coefficients and resonant frequencies of the MSA at different tuning magnetic states for three cavity configurations. These parameters are then experimentally measured using an impedance tube for model validation, demonstrating good agreement between the measured and predicted values. Subsequent analysis reveals the iron-platelet-magnet resonance mechanism introduced by the tuned magnetic field is the main factor behind the appearance and shift of absorption peaks in the low-frequency region, which are mostly independent of the back cavity. In other words, the MSA with a back cavity of any size can achieve sound absorption in the low-frequency region. This demonstrates the potential of the structure in achieving an ultra-thin, low-frequency, tunable sound-absorber design that can be adapted to different noise sources.

Comparative transcriptome analysis reveals the mechanism involving ethylene and cell wall modification related genes in Diospyros kaki fruit firmness during ripening.

Rapid loss of firmness is a major handicap for persimmon (Diospyros kaki Thunb.) transportation and retail. The present study employed a comparative transcriptomic approach to elucidate the mechanism involving ethylene and cell wall modification related genes in fruit firmness control of two cultivars during post harvest ripening. In contrast to the short shelf life cultivar (Mopan), the long shelf life cultivar (Yoho) kept high firmness during ripening. Extensive loss of firmness in Mopan drove an intense transcriptional activity. Globally, Mopan and Yoho shared very few common differentially expressed structural genes and regulators. Yoho strongly repressed the expression of ACC synthase and several classes of cell wall degradation genes at the onset of ripening and only induced them during late ripening period. Various ERF, WRKY, MYB, bHLH transcription factors were found highly active during fruit ripening. Overall, this study generates novel gene resources as important tools for extending persimmon shelf life.

Self-propelled plate in wakes behind tandem cylinders.

Fish may take advantage of environmental vortices to save the cost of locomotion. The complex hydrodynamics shed from multiple physical objects may significantly affect fish refuging (holding stationary). Taking a model of a self-propelled flapping plate, we numerically studied the locomotion of the plate in wakes of two tandem cylinders. In most simulations, the plate heaves at its initial position G_{0} before the flow comes (releasing Style I). In the typical wake patterns, the plate may hold stationary, drift upstream, or drift downstream. The phase diagrams of these modes in the G_{0}-A plane for the vortex shedding patterns were obtained, where A is the flapping amplitude. It is observed that the plate is able to hold stationary at multiple equilibrium locations after it is released. Meanwhile, the minimum amplitude and the input power required for the plate seem inversely proportional to the shedding vortex strength. The effect of releasing style was also investigated. If the plate keeps stationary and does not flap until the vortex shedding is fully developed (releasing Style II), then the plate is able to hold stationary at some equilibrium locations but the flapping plate has a very minor effect on the shedding vortices. However, in Style I, the released plate is able to achieve more equilibrium locations through adjusting the phase of vortex shedding. The effort of the preflapping in Style I is not in vain, because although it consumes more energy, it becomes easier to hold stationary later. The relevant mechanism is explored.

Membrane-type acoustic metamaterials with tunable frequency by a compact magnet.

In this letter, a membrane-type acoustic metamaterial with a compact magnet (MAMM) is presented. To investigate its frequency-tunable properties, a theoretical model considering both static and dynamic effects of magnetic force is established. Analytical investigations indicate that tuning of the magnetic force exerted on the centralized rigid iron platelet leads to the shift in the MAMM's transmission loss peaks. The experimental anti-resonance frequencies of the MAMM derived from the impedance tube measurements exhibited good consistency with those predicted theoretically. Continuously tuned in a wide frequency range, this structure can well adapt to the noise source variation in insulation design.

Soluble Urokinase Plasminogen Activator Receptor is Associated with Coronary Artery Calcification and Cardiovascular Disease in Patients Undergoing Hemodialysis.

BACKGROUND/AIMS: Cardiovascular disease (CVD) is an important cause of morbidity and mortality in hemodialysis patients. Vascular calcification is thought to play an important role in causing CVD. Soluble urokinase plasminogen activator receptor (suPAR) is a biomarker strongly predictive of cardiovascular outcomes in the pathogenesis of diabetic patients with renal disease treated with hemodialysis. We investigated the relationship between suPAR and coronary artery calcification (CAC) in patients undergoing maintenance hemodialysis. METHODS: A total of 99 adult hemodialysis patients were enrolled in this study. Plasma samples were analyzed for suPAR with an enzyme-linked immunosorbent assay and the CAC score was determined with multidetector computed tomography. The occurrence of cardiovascular events and all-cause mortality during follow-up were recorded from January 1, 2010 to June 1, 2016. RESULTS: In 99 patients treated with maintenance hemodialysis, 91 (91.9%) had varying degrees of CAC, and suPAR correlated positively with the CAC score in a Spearman analysis. In a mean follow-up period of 33 months, 36 patients (36.4%) experienced at least one cardiovascular event. When the quartiles of suPAR concentrations were used as the cutoff points for a subgroup analysis, the incidence of CVD and all-cause mortality was much higher in the higher quartiles of suPAR. In a univariate Cox regression analysis, high suPAR was a risk factor for CVD and all-cause mortality. CONCLUSION: suPAR is associated with the CAC score and is a risk factor for new-onset CVD in patients undergoing hemodialysis.

Membrane acoustic metamaterial absorbers with magnetic negative stiffness.

A membrane absorber usually requires a large back cavity to achieve low-frequency sound absorption. This paper describes the design of a membrane acoustic metamaterial absorber in which magnetic negative stiffness is employed to reduce the size of the back cavity. As a baseline for the present research, analysis of a typical membrane sound absorber based on an equivalent circuit model is presented first. Then, a theoretical model is established by introducing negative stiffness into a standard absorber. It is demonstrated that a small cavity with negative stiffness can achieve the acoustic impedance of a large cavity and that the absorption peak is shifted to lower frequencies. Experimental results from an impedance tube test are also presented to validate this idea and show that negative stiffness can be employed to design compact low-frequency membrane absorbers.

The complex jujube genome provides insights into fruit tree biology.

The jujube (Ziziphus jujuba Mill.), a member of family Rhamnaceae, is a major dry fruit and a traditional herbal medicine for more than one billion people. Here we present a high-quality sequence for the complex jujube genome, the first genome sequence of Rhamnaceae, using an integrated strategy. The final assembly spans 437.65 Mb (98.6% of the estimated) with 321.45 Mb anchored to the 12 pseudo-chromosomes and contains 32,808 genes. The jujube genome has undergone frequent inter-chromosome fusions and segmental duplications, but no recent whole-genome duplication. Further analyses of the jujube-specific genes and transcriptome data from 15 tissues reveal the molecular mechanisms underlying some specific properties of the jujube. Its high vitamin C content can be attributed to a unique high level expression of genes involved in both biosynthesis and regeneration. Our study provides insights into jujube-specific biology and valuable genomic resources for the improvement of Rhamnaceae plants and other fruit trees.

[Effect of "Xuebijing injection" on expression of high mobility group box-1 protein and acute liver injury in rats with scald injury].

OBJECTIVE: To investigate the effect of "Xuebijing injection" (Xuebijing in brief) on expression of hepatic high mobility group box-1 protein (HMGB1) and acute liver injury in rats with scald injury. METHODS: Seventy-eight rats were divided into sham scald group (n = 18), scald group (n = 30), and Xuebijing treatment group (n = 30). Rats in the latter 2 groups were subjected to 30% full-thickness scald injury followed with delayed resuscitation. These rats were sacrificed at 8th, 24th, and 72nd post-injury hour (PIH) to collect specimens. The hepatic pathological changes were observed. Serum levels of ALT and AST were detected. HMGB1 mRNA level in hepatic tissue was detected by the reverse transcription polymerase chain reaction. Protein relative expression quantity of HMGB1 in hepatic tissue was determined with Western blot and immunohistochemistry. Outcomes were denoted in integral absorbance ratio and absorbance value respectively. RESULTS: Massive infiltration of inflammatory cells in hepatic tissues was observed in scald group under light microscope, especially at 24th PIH, and it was decreased in quantity in Xuebijing treatment group. Compared with those of sham scald group, both mRNA and protein expressions of HMGB1 in hepatic tissue of scald group were significantly enhanced during 8-72 PIH (P < 0.05 or P < 0.01), along with markedly increased serum levels of ALT and AST (P < 0.05 or P < 0.01). Compared with those in scald group at 24h and 72nd PIH, hepatic HMGB1 mRNA expressions (0.75 +/- 0.12 vs. 0.60 +/- 0.15 and 0.78 +/- 0.11 vs. 0.55 +/- 0.07, respectively) and protein values (200 +/- 13 vs. 163 +/- 13 and 175 +/- 14 vs. 160 +/- 16, respectively) in Xuebijing treatment group were markedly down-regulated (P < 0.05 or P < 0.01), and serum levels of ALT and AST decreased in different degrees (P < 0.05 or P < 0.01). CONCLUSIONS: HMGB1, the delay-appearing inflammatory mediator, is involved in the pathogenesis of inflammatory response in hepatic tissue in severely scalded rats. Treatment with Xuebijing can markedly down-regulate hepatic HMGB1 expression and protect liver against acute injury induced by delayed resuscitation.

[Effect of ethyl pyruvate on renal high mobility group box-1 protein expression and acute kidney injury in rats with delayed resuscitation after thermal injury].

OBJECTIVE: To investigate the effect of ethyl pyruvate (EP) on high mobility group box-1 protein (HMGB1) expression in renal tissue and acute kidney injury in rats with delayed resuscitation after thermal injury. METHODS: Seventy-eight Wistar rats subjected to 30% total body surface area full-thickness thermal injury followed with delayed resuscitation were divided into 3 groups: sham group (n = 18), injury group (n = 30) and EP group (n = 30). Renal tissue and blood samples were harvested to determine HMGB1 mRNA as well as its protein expression and renal function parameter at the 8, 24, 72 h post the "injury". HMGB1 mRNA was semi-quantitatively measured by reverse transcription polymerase chain reaction taking GAPDH as an internal standard, and HMGB1 protein expression was determined by Western blot and immunohistochemistry. Blood urea nitrogen (BUN) levels were measured with automatic biochemistry analyzer. The pathological changes of renal tissues were examined using HE staining. RESULTS: Compared with sham controls, both mRNA and protein expressions of HMGB1 in injury group were significantly enhanced in kidneys at 8 - 72 h after thermal injury (P < 0.05), meanwhile serum BUN levels were markedly increased (P < 0.05). Compared with injury group, the renal HMGB1 mRNA and protein expressions were markedly down-regulated in EP group at 8 h, 24 h and 72 h post injury (P < 0.05), respectively, and meanwhile serum BUN levels were reduced significantly (P < 0.05). Inflammatory cell infiltration was found in renal tissues following injury, and kidney injury was markedly alleviated after treatment with EP. CONCLUSIONS: It indicated that HMGB1 appears to be involved in the pathogenesis of post-burn acute kidney injury. Treatment with EP reduces renal HMGB1 expression, and protects against acute kidney injury secondary to delayed resuscitation after major burns.

[Effect of Xuebijing injection on renal high mobility group box-1 protein expression and acute kidney injury in rats after scald injury].

OBJECTIVE: To investigate the change in renal high mobility group box-1 protein (HMGB1) levels, and the effect of Chinese traditional medicine-Xuebijing injection on HMGB1 expression as well as acute kidney injury in rats after scald injury. METHODS: Wistar rats were subjected to 30% full-thickness scald injury followed with delayed resuscitation. Totally 78 animals were divided into sham scald group (n=18), scald injury group (n=30), and Xuebijing injection treatment group (n=30). All animals were sacrificed at 8, 24, and 72 hours postburn. Renal tissue and blood samples were harvested to determine HMGB1 mRNA as well as protein expression and organ functional parameters. HMGB1 mRNA level was semi-quantitatively measured by the reverse transcription polymerase chain reaction taking GAPDH as an internal standard, and protein expressions of HMGB1 were detected by both Western blot and immunohistochemistry. Serum creatinine (Cr) contents were measured by automatic biochemistry analyzer. In addition, pathological lesions in kidney were observed under light microscope using HE staining. RESULTS: Compared with sham scald group, both mRNA and protein expressions of HMGB1 were significantly enhanced in the kidney at 8, 24, and 72 hours after scald injury (P<0.05, P<0.01), meanwhile serum Cr contents were markedly increased following acute insults (P<0.05, P<0.01). Treatment with Xuebijing injection could markedly down-regulated renal HMGB1 mRNA expression and protein release at 24 hours and 72 hours (P<0.05, P<0.01), and significantly reduced serum Cr content following scald injury (P<0.05). Many inflammatory cells in renal tissues were observed using light microscope following scald. The histological morphology of kidney lesions was a-HMGB1, a late mediator, appears to be inmeliorated after treatment with Xuebijing injection. CONCLUSIONS: volved in the pathogenesis of excessive inflammatory response and acute kidney damage. Treatment with Xuebijing injection can inhibit HMGB1 synthesis and release in renal tissues, and may prevent the development of acute kidney injury induced by serious scald injury.

[Effect of treatment with ethyl pyruvate on multiple organ dysfunction and mortality following delayed resuscitation after burn injury in rat].

OBJECTIVE: To observe the effects of ethyl pyruvate (EP) treatment on multiple organ dysfunction and mortality following delayed resuscitation after burn injury in rat, and investigate the mechanisms of its protective effect. METHODS: Male Wistar rats were subjected to 30% full-thickness scald injury followed with delayed resuscitation (6 hours postburn). (1) One hundred and thirty male Wistar rats were randomly divided into sham scald group (n=10), scald group (n=60) and EP-treatment group (n=60). In the scald group, 40 ml/kg normal saline was injected intraperitoneally 6 hours after scald injury for resuscitation, and it was repeated periodically. Following delayed resuscitation after burn injury, EP was injected at a dose of 40 mg/kg every 12 hours in EP-treatment group for 3 days. According to the interventional time points, rats of scald and EP-treatment groups were respectively divided in three subgroups: 2 hours prior to scald (n=20), 2 hours after scald (n=20), and 12 hours after scald (n=20). The mortality of animals was observed with 7 days as the cut point. (2) Seventy male rats were randomly divided into sham scald group (n=10), scald group (n=30), and EP-treatment group (n=30). In EP-treatment group, 40 mg/kg EP was injected intraperitoneally 2 hours after scald. Animals were sacrificed at 12, 24, and 72 hours postburn, and serum samples were collected to determine the organ functional parameters, and lung tissue was obtained for measurement of myeloperoxidase (MPO) activity. RESULT: The 7-day mortality in scald and EP-treatment groups (EP given 12 hours postburn) was 75.0% and 35.0% respectively (P<0.05). Compared with scald group, serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), creatinine (Cr) and creatine kinase (CK) levels were markedly decreased in EP-treatment group at 12 to 24 hours postburn (P<0.05 or P<0.01), and pulmonary MPO activities were also significantly declined at 12 to 72 hours following burns (P<0.05 or P<0.01). CONCLUSION: EP can obviously improve the outcome in rats with delayed resuscitation after burn injury, and prevent the development of multiple organ dysfunction secondary to major burns.