Meta-silencer with designable timbre

Timbre,as one of the essential elements of sound,plays an important role in determining sound properties,whereas its manipulation has been remaining challenging for passive mechanical systems due to the intrinsic dispersion nature of resonances.Here,we present a meta-silencer supporting intensive mode density as well as highly tunable intrinsic loss and offering a fresh pathway for designable timbre in broadband.Strong global coupling is induced by intensive mode density and delicately modulated with the guidance of the theoretical model,which efficiently suppresses the resonance dispersion and provides desirable frequency-selective wave-manipulation capacity for timbre tuning.As proof-of-concept demonstrations for our design concepts,we propose three meta-silencers with the designing targets of high-efficiency broadband sound attenuation,efficiency-controlled sound attenuation and designable timbre,respectively.The proposed meta-silencers all operate in a broadband frequency range from 500 to 3200 Hz and feature deep-subwavelength sizes around 50 mm.Our work opens up a fundamental avenue to manipulate the timbre with passive resonances-controlled acoustic metamaterials and may inspire the development of novel multifunctional devices in noise-control engineering,impedance engineering,and architectural acoustics.

An Exact Solution for Acoustic Simulation Based Transmission Loss Optimization of Double-Chamber Silencer

The optimization of the acoustic silencer volume is very important to develop it and to get high-performance,the importance of the silencer was appeared in industrial field to eliminate the noise of the duct by efficient and economical method.The main goal of this research is to optimize the transmission loss(TL)by analytical method of the Double-Chamber Silencer(DCS),the TL has been selected as the main parameter in silencer because it does not based on the source or the termination impedances.First we calculated the power transmission coefficient(PTC)and the TL of an acoustic silencer,then used the Lagrange method to optimize the silencer length.All calculation of silencer data is obtained by solving the governing equations in commercial software Matlab®.A several calculations for different silencer length at many frequency ranges were performed simultaneously.Finally,this research supports the efficient and rapid techniques for DCS optimal design under narrow space.The results show that the acoustic TL is maximized at the desired frequency.

CFD analysis of sound pressure in tank gun muzzle silencer

The high pressure waves generated due to muzzle blast flow of tank gun during firing is a critical issue to examine. The impulsive noise from the gun has various negative effects such as damage of human bodies, damage of structures, creating an environmental, social problem and also military problems such as exposure of location of troops. This high pressure impulsive sound, generated during the blast flow, was studied and attenuated. An axisymmetric computational domain was constructed by employing Spalart Allmaras turbulence model. Approximately 90% of pressure and 20 dB of sound level are reduced due to the use of the three baffle silencer at the muzzle end of the gun barrel, in comparison with the tank gun without silencer. Also, the sound pressure level at different points in the ambient region shows the same attenuation in results. This study will be helpful to understand the blast wave characteristics and also to get a good idea to design silencer for large caliber weapon system.

Time-domain CFD computation and analysis of acoustic attenuation performance of water-filled silencers

The multi-dimensional time-domain computational fluid dynamics(CFD) approach is extended to calculate the acoustic attenuation performance of water-filled piping silencers. Transmission loss predictions from the time-domain CFD approach and the frequency-domain finite element method(FEM) agree well with each other for the dual expansion chamber silencer, straight-through and cross-flow perforated tube silencers without flow. Then, the time-domain CFD approach is used to investigate the effect of flow on the acoustic attenuation characteristics of perforated tube silencers. The numerical predictions demonstrate that the mean flow increases the transmission loss, especially at higher frequencies, and shifts the transmission loss curve to lower frequencies.

Trans-acting factors from the human fetal liver bindingto the human ε-globin gene silencer

The developmental stage-specific silencing of the human ε-globin gene during embryonic life is controlled, inpart, by the silencer (-392bp～-177bp) upstream of thisgene. In order to elucidate its role, the nuclear extractfrom the human fetal liver has been prepared and the interactions between trans-acting factors and this silencerelement have been examined. By using DNasel footprinting assay, a major protected region from -278bp to -235bpwithin this silencer element was identified. Furthermore,we found in gel mobility shift assay and Southwestern blotting assay that there were at least four trans-acting factors (MW ≈ 32, 28, 26 and 22kD) in the nuclear extractisolated from the human fetal liver, which could specifically bind to this region. Our results suggested that thesetrans-acting factors might play an important role in silencing the human embryonic ε-globin gene expression at thefetal stage through the interactions with this silencer.

Application of dual reciprocity boundary element method to predict acoustic attenuation characteristics of marine engine exhaust silencers

In marine engine exhaust silencing systems, the presence of exhaust gas flow influences the sound propagation inside the systems and the acoustic attenuation performance of silencers. In order to investigate the effects of three-dimensional gas flow and acoustic damping on the acoustic attenuation characteristics of marine engine exhaust silencers, a dual reciprocity boundary element method (DRBEM) was developed. The acoustic governing equation in three-dimensional potential flow was derived first, and then the DRBEM numerical procedure is given. Compared to the conventional boundary element method (CBEM), the DRBEM considers the second order terms of flow Mach number in the acoustic governing equation, so it is suitable for the cases with higher Mach number subsonic flow. For complex exhaust silencers, it is difficult to apply the single-domain boundary element method, so a substructure approach based on the dual reciprocity boundary element method is presented. The experiments for measuring transmission loss of silencers are conducted, and the experimental setup and measurements are explained. The transmission loss of a single expansion chamber silencer with extended inlet and outlet were predicted by DRBEM and compared with the measurements. The good agreements between predictions and measurements are observed, which demonstrated that the derived acoustic governing equation and the DRBEM numerical procedure in the present study are correct.

Reducing Occupational Noise Propagated from Centrifugal Fan through Dissipative Silencers:A Field Study

Acoustic performance of dissipative silencer was evaluated to determine the effectiveness of perforated duct porosity and absorbent material density in reducing occupational noise exposure propagated from centrifugal fan.Design charts were applied to predict noise reduction and length of a dissipative silencer.Dissipative silencers with various punched duct porosity(14%,30%and 40%)and sound absorbent density(80 Kg/m^(3),120 Kg/m^(3),and 140 Kg/m^(3))were designed and fabricated.According to ISO9612 and ISO11820,noise level was measured before and after installing all nine test silencers at fixed workstations around the discharge side of a centrifugal fan in a manufacturing plant.On average,the noise level at the discharge side of a fan without silencer was measured to be 93.6 dBA,whereas it was significantly mitigated by 67.4 dBA to 70.1 dBA after installing all silencers.Dynamic insertion loss for a dissipative silencer with 100 cm length was predicted to be 27.9 dB,which was in agreement with experimental ones.Although,there was no significant differences between insertion loss of silencers,the one with 30%porosity and 120 Kg/m^(3)rock wool density had the highest insertion loss of 26.2 dBA.Dissipative silencers noticeably reduced centrifugal fan noise exposures.Increasing sound absorbent density and duct porosity up to a certain limit could probably be effective in noise reduction of dissipative silencers.

ASUS EN6600GT Silencer

这款采用nVidia GeForce 6600GT的产品最大的特点在于其100%的静音设计，由于采用了独特的热管散热系统，这款显卡上并未安装任何主动散热装置，它的主散热片被设置在显卡上方，并且可以向右侧旋转90°,

宁静高端——华硕EAX800 Silencer显卡

出色的游戏引擎总是对显卡提出更高要求，但随高端显卡而来的便是较大的系统功耗和呼啸的风声。在性能与噪声之间如何取舍，总是玩家们心中的痛。华硕最近推出的EAX800 Silencer显卡装备了独创的SilentCool技术，在拥有较高游戏性能的同时，也给玩家带来了一些宁静。

Cotton ethylene response factor Gh ERF91 is involved in the defense against Verticillium dahliae

Verticillium dahliae causes significant losses in cotton production.To reveal the mechanism of the defense response to V.dahliae in cotton,transcriptomic analyses were performed using cotton cultivars M138(V.dahliae-resistant)and P2(V.dahliae-susceptible).The results revealed 11,076 and 6,640 differentially expressed genes(DEGs)in response to V.dahliae,respectively.The weighted gene co-expression network analysis of 4,633 transcription factors(TFs)indicated a“MEblue”module containing 654 TFs that strongly correlate with resistance to V.dahliae.Among these TFs,the ethylene response factor Ghi_A05G10166(GhERF91)was identified as a putative hub gene with a defense response against V.dahliae.A virus-induced gene silencing assay and exogenous application of ethephon showed that GhERF91 is activated by ethylene and positively regulates the response to V.dahliae exposure in cotton.This study provides fundamental transcriptome data and a putative causal gene(GhERF91)associated with resistance to V.dahliae,as well as genetic resources for breeding V.dahliae-resistant cotton.

Host-induced gene silencing of the Verticillium dahliae thiamine transporter protein gene(VdThit)confers resistance to Verticillium wilt in cotton

Verticillium wilt(VW),induced by the soil-borne fungus Verticillium dahliae(Vd),poses a substantial threat to a diverse array of plant species.Employing molecular breeding technology for the development of cotton varieties with heightened resistance to VW stands out as one of the most efficacious protective measures.In this study,we successfully generated two stable transgenic lines of cotton(Gossypium hirsutum L.),VdThitRNAi-1 and VdThit-RNAi-2,using host-induced gene silencing(HIGS)technology to introduce double-stranded RNA(dsRNA)targeting the thiamine transporter protein gene(VdThit).Southern blot analysis confirmed the presence of a single-copy insertion in each line.Microscopic examination showed marked reductions in the colonization and spread of Vd-mCherry in the roots of VdThit-RNAi cotton compared to wild type(WT).The corresponding disease index and fungal biomass of VdThit-RNAi-1/2 also exhibited significant reductions.Real-time quantitative PCR(qRT-PCR)analysis demonstrated a substantial inhibition of VdThit expression following prolonged inoculation of VdThit-RNAi cotton.Small RNA sequencing(sRNA-Seq)analysis revealed the generation of a substantial number of VdThit-specific siRNAs in the VdThit-RNAi transgenic lines.Additionally,the silencing of VdThit by the siVdThit produced by VdThit-RNAi-1/2 resulted in the elevated expression of multiple genes involved in the thiamine biosynthesis pathway in Vd.Under field conditions,VdThit-RNAi transgenic cotton exhibited significantly enhanced disease resistance and yield compared with WT.In summary,our findings underscore the efficacy of HIGS targeting VdThit in restraining the infection and spread of Vd in cotton,thereby potentially enabling the development of cotton breeding as a promising strategy for managing VW.

Knockdown of the atypical protein kinase genes GhABC1K2-A05 and GhABC1K12-A07 make cotton more sensitive to salt and PEG stress

Activity of bc1 complex kinase(ABC1K)is an atypical protein kinase(aPK)that plays a crucial role in plant mitochondrial and plastid stress responses,but little is known about the responses of ABC1Ks to stress in cotton(Gossypium spp.).Here,we identified 40 ABC1Ks in upland cotton(Gossypium hirsutum L.)and found that the Gh ABC1Ks were unevenly distributed across 17 chromosomes.The GhABC1K family members included 35 paralogous gene pairs and were expanded by segmental duplication.The GhABC1K promoter sequences contained diverse cis-acting regulatory elements relevant to hormone or stress responses.The qRT-PCR results revealed that most Gh ABC1Ks were upregulated by exposure to different stresses.Gh ABC1K2-A05 and Gh ABC1K12-A07 expression levels were upregulated by at least three stress treatments.These genes were further functionally characterized by virus-induced gene silencing(VIGS).Compared with the controls,the Gh ABC1K2-A05-and Gh ABC1K12-A07-silenced cotton lines exhibited higher malondialdehyde(MDA)contents,lower catalase(CAT),peroxidase(POD)and superoxide dismutase(SOD)activities and reduced chlorophyll and soluble sugar contents under NaCl and PEG stress.In addition,the expression levels of six stress marker genes(Gh DREB2A,Gh SOS1,Gh CIPK6,Gh SOS2,Gh WRKY33,and Gh RD29A)were significantly downregulated after stress in the Gh ABC1K2-A05-and Gh ABC1K12-A07-silenced lines.The results indicate that knockdown of Gh ABC1K2-A05 and Gh ABC1K12-A07 make cotton more sensitive to salt and PEG stress.These findings can provide valuable information for intensive studies of Gh ABC1Ks in the responses and resistance of cotton to abiotic stresses.

Transcription factor CabHLH035 promotes cold resistance and homeostasis of reactive oxygen species in pepper

Plant basic helix-loop-helix(bHLH)transcription factors(TFs)play central roles in various abiotic stresses.However,its role in plant cold resistance is largely unknown.Previously,we characterised CaNAC035 in pepper,which positively regulates tolerance to cold,salt and drought stresses tolerance.Here,we identified CabHLH035,a CaNAC035-interacting protein in pepper.To explore its functions in cold stress tolerance,we silenced the gene in pepper via virus-induced gene silencing(VIGS)and overexpressed the gene in Arabidopsis.The results showed that CabHLH035 expression was induced by cold treatment,and silencing of CabHLH035 decreased cold stress tolerance.Conversely,overexpression of CabHLH035 in Arabidopsis increased cold stress tolerance.To investigate homologs genes of C-repeat binding factor(CBF)pathway proteins and reactive oxygen species(ROS)marker gene expression blocking by CabHLH035,we performed yeast one-hybrid(Y1H),dual luciferase and electrophoretic mobility shift assay experiments.The results showed that CabHLH035 bound to the region upstream of the CaCBF1A and CaAPX promoters.Additionally,CaCBF1A bound to the CaDHN4 promoter.Taken together,our results showed that CabHLH035 plays a crucial role in cold stress tolerance and its potential as a target for breeding cold-resistant crops.The findings provide a basis for studying the functions and regulatory network of cold stress tolerance in pepper.

Nanocarrier-mediated siRNA delivery:a new approach for the treatment of traumatic brain injury-related Alzheimer's disease

Traumatic brain injury and Alzheimer's disease share pathological similarities,including neuronal loss,amyloid-βdeposition,tau hyperphosphorylation,blood-brain barrier dysfunction,neuroinflammation,and cognitive deficits.Furthermore,traumatic brain injury can exacerbate Alzheimer's disease-like pathologies,potentially leading to the development of Alzheimer's disease.Nanocarriers offer a potential solution by facilitating the delive ry of small interfering RNAs across the blood-brain barrier for the targeted silencing of key pathological genes implicated in traumatic brain injury and Alzheimer's disease.U nlike traditional approaches to neuro regeneration,this is a molecula r-targeted strategy,thus avoiding non-specific drug actions.This review focuses on the use of nanocarrier systems for the efficient and precise delive ry of siRNAs,discussing the advantages,challenges,and future directions.In principle,siRNAs have the potential to target all genes and non-targetable protein s,holding significant promise for treating various diseases.Among the various therapeutic approaches currently available for neurological diseases,siRNA gene silencing can precisely"turn off"the expression of any gene at the genetic level,thus radically inhibiting disease progression;however,a significant challenge lies in delivering siRNAs across the blood-brain barrier.Nanoparticles have received increasing attention as an innovative drug delive ry tool fo r the treatment of brain diseases.They are considered a potential therapeutic strategy with the advantages of being able to cross the blood-brain barrier,targeted drug delivery,enhanced drug stability,and multifunctional therapy.The use of nanoparticles to deliver specific modified siRNAs to the injured brain is gradually being recognized as a feasible and effective approach.Although this strategy is still in the preclinical exploration stage,it is expected to achieve clinical translation in the future,creating a new field of molecular targeted therapy and precision medicine for the treatment of Alzheimer's disease associated with traumatic brain injury.

Host-Induced Gene Silencing of Effector AGLIP1 Enhanced Resistance of Rice to Rhizoctonia solani AG1-IA

Rice sheath blight, caused by Rhizoctonia solani AG1-IA, is a major disease in rice-growing areas worldwide. Effectors of phytopathogenic fungi play important roles during the infection process of fungal pathogens onto their host plants. However, the molecular mechanisms by which R. solani effectors regulate rice immunity are not well understood. Through prediction, 78 candidate effector molecules were identified. Using the tobacco rattle virus-host induced gene silencing(TRV-HIGS) system, 45 RNAi constructs of effector genes were infiltrated into Nicotiana benthamiana leaves. The results revealed that eight of these constructs resulted in a significant reduction in necrosis caused by infection with the AG1-IA strain GD-118. Additionally, stable rice transformants carrying the double-stranded RNA construct for one of the effector genes, AGLIP1, were generated to further verify the function of this gene. The suppression of the AGLIP1 gene increased the resistance of both N. benthamiana and rice against GD-118, and also affected the growth rate of GD-118, indicating that AGLIP1 is a key pathogenic factor. Small RNA sequencing showed that the HIGS vectors were processed into si RNAs within the plants and then translocated to the fungi, leading to the silencing of the target genes. As a result, AGLIP1 might be an excellent candidate for HIGS, thereby enhancing crop resistance against the pathogen and contributing to the control of R. solani infection.

TM9SF1 is implicated in promoting the proliferation and invasion of bladder cancer cells

Zhuo et al looked into the part of transmembrane 9 superfamily member 1(TM9SF1)in bladder cancer(BC),and evaluated if it can be used as a therapeutic target.They created a permanent BC cell line and tested the effects of TM9SF1 overexpression and suppression on BC cell growth,movement,invasion,and cell cycle advancement.Their results show that TM9SF1 can boost the growth,movement,and invasion of BC cells and their access into the G2/M stage of the cell cycle.This research gives a novel direction and concept for targeted therapy of BC.

“Do You Want This Life of Yours?”-Quest for Identity in Chenmo Zhi Dao

The novel Islands of Silence by Wei-chen Su,a female writer from Taiwan,explores the identity and roles of women by portraying two characters with the same name,Chenmian,who struggles with her unbearable reality from her family,desperately trying to build a“solid”identity for herself.The character is so eager to have ways out that she imagines another totally different self,with a happy marriage in a lovely family.In the novel,the single Chenmian travels around the world while the alter ego lives a stable life in Taiwan.Through the intertwined story lines of both Chenmians,Su challenged our traditional understanding of female identity;attempted to destabilize the traditional concepts of womanhood.This concept starts with Chenmian’s quest for an essential womanhood,but ends with her realization of its indefiniteness.

Writing the Silenced Female Body, Scrutinizing the Grand Narrative of Colonization and Decolonization: The Body in Zoë Wicomb’s David’s Story

David’s Story by Zoë Wicomb addresses the complexities of representing female suffering and the limitations of traditional historical narratives in capturing the experiences of marginalized bodies.It challenges the grand narratives of national history by emphasizing the indispensable role of women’s experiences.Through characters like Dulcie and Rachael,Wicomb portrays the female body as a site of resistance and resilience,highlighting the need for more nuanced and inclusive ways of documenting history.Underscoring the inexpressibility of trauma and the limitations of language and representation,the novel self-reflexively acknowledges its own aporia of completing the narrative,embodying the ongoing struggle to capture the full breadth of human experience.

Stress response silencing by an E3 ligase mutated in neurodegeneration

Stress response pathways detect and alleviate adverse conditions to safeguard cell and tissue homeostasis,yet their prolonged activation induces apoptosis and disrupts organismal health1-3.How stress responses are turned off at the right time and place remains poorly understood.Here we report a ubiquitin-dependent mechanism that silences the cellular response to mitochondrial protein import stress.

IBM1-dependent H3K9 demethylation enables self-silencing of an exogenous silencer for the non-cell autonomous silencing of an endogenous target gene

RNA silencing(RNAi)is a nucleotide sequence-specific process that results in blockage of gene expression(Baulcombe,2004,2005;Gunter Meister,2004;Vaucheret,2006;Chinnusamy and Zhu,2009;Heo and Kim,2009;Matzke et al.,2009;Simon and Meyers,2011).In plants,post-transcriptional gene silencing(PTGS)occurs in the cytoplasm that is induced by small RNAs(sRNAs),which are the products of double-stranded RNAs(dsRNAs)processed by Dicer-like ribonucleases and achieve specificity through base pairing with targeted RNA sequences(Carmell and Hannon,2004;Gunter Meister,2004;Gasciolli et al.,2005).In an alternative pathway occurring in the nucleus,sRNAs corresponding to promoter sequences direct the silencing machinery to block the transcription of homologous promoters(transcriptional gene silencing,TGS).This process requires 24-nt sRNAs for de novo DNA methylation,a process known as RNA-directed DNA methylation(RdDM)(James P.Jackson and Jacobsen,2002;Matzke and Birchler,2005;Matzke et al.,2007;Zilberman et al.,2007;Wierzbicki et al.,200&Zilberman,2008).Histone modifications also play an important role in the establishment and maintenance of DNA methylation(Zuzana Jasencakova,2003;Ooi et al.,2007;Cedar and Bergman,2009;Law and Jacobsen,2010).In plants,it has been shown that the transcription of exogenous transgene transcribing inverted-repeat(exo-/R)sequences produces dsRNAs,triggering exo-//?PTGS that is negatively autoregulated through methylation spreading/transitive silencing.This transitive silencing「einforces the self-silencing of exo-//?and leads to reduced exo-//?PTGS and exo-/R-derived sRNA production.exo-/R-derived sRNAs function as mobile signals to trigger sRNA-mediated non-cell autonomous silencing of an endogenous homologous target gene(endo-gene)(Dong et al.,2011).It remains unknown whether histone modifications play a role in the exo-IR-triggered endo-gene silencing.