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At Schizosaccharomyces pombe centromeres, heterochromatin formation is required for de novo incorporation of the histone H3 variant CENP-ACnp1, which in turn directs kinetochore assembly and ultimately chromosome segregation during mitosis. Noncoding RNAs (ncRNAs) transcribed by RNA polymerase II (Pol II ) directs heterochromatin formation through not only the RNA interference (RNAi) machinery but also RNAi-independent RNA processing factors. Control of centromeric ncRNA transcription is therefore a key factor for proper centromere function. We here demonstrate that Mediator directs ncRNA transcription and regulates centromeric heterochromatin formation in fission yeast. Mediator colocalizes with Pol II at centromeres, and loss of the Mediator subunit Med20 causes a dramatic increase in pericentromeric transcription and desilencing of the core centromere. As a consequence, heterochromatin formation is impaired via both the RNAi-dependent and -independent pathways, resulting in loss of CENP-ACnp1 from the core centromere, a defect in kinetochore function, and a severe chromosome segregation defect. Interestingly, the increased centromeric transcription observed in med20 Δ cells appears to directly block CENP-ACnp1 incorporation since inhibition of Pol II transcription can suppress the observed phenotypes. Our data thus identify Mediator as a crucial regulator of ncRNA transcription at fission yeast centromeres and add another crucial layer of regulation to centromere function. [ABSTRACT FROM AUTHOR]

The article offers information on a study which synthesized and investigated the role of Sr1+xCo0.8Fe0.2O3 oxides as potential oxygen absorbents for high temperature oxygen separation processes. Observations on the A-site ion deficient Sr0.95Co0.8Fe0.2O3 and Sr0.9Co0.8Fe0.2O3 oxides are described. Preparation of materials and oxygen absorption and desorption of materials are detailed.

Chemical vapor deposition (CVD) with methyldiethoxysilane (MDES) for MFI zeolitic pore size reduction is an effective way to improve the H2/CO2separation factor of zeolite membranes. However, only good membranes with few intercrystalline defects are able to show considerable improvement in H2/CO2separation factor through CVD modification. It is unreliable to evaluate the membrane quality on the basis of the H2/SF6or N2/SF6ideal separation factor because the SF6adsorption-induced crystal swelling causes shrinkage of the intercrystalline defects in the MFI zeolite membranes. In this study, the quality of MFI zeolite membranes was evaluated on the basis of their performance in separating equimolar H2/CO2mixture gas at room temperature. High-quality membranes are more selective to CO2molecules rather than H2at room temperature due to the adsorption of CO2into the zeolitic pores and blocking of the pore channels for H2diffusion. The effectiveness of the quality evaluation method was confirmed by on-stream CVD modification of MFI zeolite membranes with different initial H2/CO2separation factors/ideal separation factors at room temperature. Experimental results showed that only those membranes with low H2/CO2separation factor at room temperature (good membranes) showed improvement in H2/CO2separation factor through CVD modification. For the CVD modified zeolite membrane with good initial quality, the permeance of H2is lower than that of He with an activated diffusion behavior for small gas molecules in the modified zeolitic pores. [ABSTRACT FROM AUTHOR]

In this paper, we designed two gemini-type amphiphiles containing diacetylene units which were covalently linked through l-lysine or l-lysine ethyl ester moiety (abbreviated as TCDA-LysAc or TCDA-LysEs) as the spacer. These amphiphiles can be easily fabricated into organized molecular films though the Langmuir−Blodgett technique and the films showed an excellent photopolymerization ability. Upon photopolymerization, TCDA-LysEs formed a purple LB film with an excellent stability, while TCDA-LysAc formed the film with mixed blue, purple, and red phases. Aligned nanofibers were observed for the TCDA-LysEs film, while a mixed domain with short fiber and rotted wood structure was obtained for TCDA-LysAc. Different supramolecular chirality was obtained for the transferred LB films although both the compounds have spacers with similar chirality. It was suggested that the subtle change in the spacer structure led to different noncovalent interactions, which subsequently affected the polymerization. Through such a molecular design, we have successfully obtained the stable purple poly(diacetylene) film. [ABSTRACT FROM AUTHOR]

Soil organic carbon (SOC) is the largest carbon pool in terrestrial ecosystems and plays a crucial role in mitigating climate change and enhancing soil productivity. Microbial-derived carbon (MDC) is the main component of the persistent SOC pool. However, current formulas used to estimate the proportional contribution of MDC are plagued by uncertainties due to limited sample sizes and the neglect of bacterial group composition effects. Here, we compiled the comprehensive global dataset and employed machine learning approaches to refine our quantitative understanding of MDC contributions to total carbon storage. Our efforts resulted in a reduction in the relative standard errors in prevailing estimations by an average of 71% and minimized the effect of global variations in bacterial group compositions on estimating MDC. Our estimation indicates that MDC contributes approximately 758 Pg, representing approximately 40% of the global soil carbon stock. Our study updated the formulas of MDC estimation with improving the accuracy and preserving simplicity and practicality. Given the unique biochemistry and functioning of the MDC pool, our study has direct implications for modeling efforts and predicting the land-atmosphere carbon balance under current and future climate scenarios. [ABSTRACT FROM AUTHOR]

Harvesting represents the crucial stage in the cultivation process of Agaricus bisporus mushrooms. An important way for the production process of Agaricus bisporus to reduce costs and increase income is to ensure timely harvest of Agaricus bisporus, reduce harvesting costs, and improve harvesting efficiency. There are many disadvantages in manual picking, such as high labor intensity, time-consuming work and high cost. In this study, a set of mushroom picking platform including climbing mechanism, picking robot, and control system was designed and developed. The picking robot consisted of a truss mechanism, an image acquisition device, a mushroom collection device, and a picking actuator. The profile picking actuator could realize the function of constant force clamping. An online size detection algorithm for Agaricus bisporus based on deep image processing was proposed. The algorithm included removal of abnormal noise points, background segmentation, coordinate conversion, and diameter detection. The precision picking system for Agaricus bisporus with coordinate compensation function controlled by Industrial Personal Computer was designed, and the visual control interface was developed based on Labview. Through the performance test, the reliability of machine vision recognition and the overall operating stability of the picking platform were verified. The test results showed that in the process of machine vision recognition, the recognition accuracy rate was higher than 92.50%, the missed detection rate was lower than 4.95%, the false detection rate was lower than 2.15%, and the diameter measurement error was less than 4.50%. The image processing algorithm had high recognition rate and small diameter measurement error, which could meet the requirements of picking operation. The picking platform’s picking success rate was higher than 95.45%, the picking damage rate was lower than 3.57%, and the picking output rate was higher than 87.09%. Compared with manual picking, the recognition accuracy rate of the picking platform was increased by 6.70%, the picking output rate was increased by 1.51%. The overall performance of the picking platform was stable and practical. [ABSTRACT FROM AUTHOR]

In this study, a Dirac cone is yielded at the corner of the Brillouin zone of a two-dimensional solid phononic crystal, which consists of a triangular array of hexagonal steel with a trilobal hole drilled in the center. With the rotation of the trilobal hole, the Dirac degeneracy switches between the deterministic form and accidental form. Every Dirac point is the critical state of a topological phase transition process, which occurs six times within an angular period of This structure offers a flexible way to achieve topological transitions and provides multiple routes to construct an interface that supports valley-dependent edge states between two topologically distinct PCs. The associated backscattering suppressed wave propagation along the multiple curved interface channels is also demonstrated. In addition, our design shows the robust propagation of topological interface states against the perturbation of the structure. This study could potentially be significant in the design of acoustic devices for practical applications, such as acoustic signal lossless transport and tunable multi-channel sound transmission. [ABSTRACT FROM AUTHOR]

We report a role for the mitochondrial single-stranded DNA binding protein (mtSSB) in regulating mitochondrial DNA (mtDNA) replication initiation in mammalian mitochondria. Transcription from the light-strand promoter (LSP) is required both for gene expression and for generating the RNA primers needed for initiation of mtDNA synthesis. In the absence of mtSSB, transcription from LSP is strongly up-regulated, but no replication primers are formed. Using deep sequencing in a mouse knockout model and biochemical reconstitution experiments with pure proteins, we find that mtSSB is necessary to restrict transcription initiation to optimize RNA primer formation at both origins of mtDNA replication. Last, we show that human pathological versions of mtSSB causing severe mitochondrial disease cannot efficiently support primer formation and initiation of mtDNA replication. [ABSTRACT FROM AUTHOR]

Exploring the concept of non-Hermitian Hamiltonians respecting parity-time symmetry with classical wave systems is of great interest as it enables the experimental investigation of parity-time-symmetric systems through the quantum-classical analogue. Here, we demonstrate unidirectional wave vector manipulation in two-dimensional space, with an all passive acoustic parity-time-symmetric metamaterials crystal. The metamaterials crystal is constructed through interleaving groove- and holey-structured acoustic metamaterials to provide an intrinsic parity-time-symmetric potential that is two-dimensionally extended and curved, which allows the flexible manipulation of unpaired wave vectors. At the transition point from the unbroken to broken parity-time symmetry phase, the unidirectional sound focusing effect (along with reflectionless acoustic transparency in the opposite direction) is experimentally realized over the spectrum. This demonstration confirms the capability of passive acoustic systems to carry the experimental studies on general parity-time symmetry physics and further reveals the unique functionalities enabled by the judiciously tailored unidirectional wave vectors in space. [ABSTRACT FROM AUTHOR]

Since the first observation of parity-time (PT) symmetry in optics, varied interesting phenomena have been discovered in both theories and experiments, such as PT phase transition and unidirectional invisibility, which turns PT-symmetric optics into a hotspot in research. Here, we report on the one-way localized Fabry–Pérot (FP) resonance, where a well-designed PT optical resonator may operate at exceptional points with bidirectional transparency but unidirectional field localization. Overtones of such one-way localized FP resonance can be classified into a blue shifted branch and a red shifted branch. Therefore, the fundamental resonant frequency is not the lowest one. We find that the spatial field distributions of the overtones at the same absolute order are almost the same, even though their frequencies are quite different. [ABSTRACT FROM AUTHOR]

This research introduced a pretreatment process -mechanical activation- for extracting rare earth elements (REE) from waste trichromatic phosphors separated from e-waste. The effects of mechanical activation on the physicochemical properties of waste trichromatic phosphors were investigated using multiple methods by scanning electron microscopy (SEM), Brunauer-Emmett-Teller measurement (BET), particle size analysis, and X-ray diffraction (XRD). The results show that mechanical activation has noticeable effects on the microstructure of waste trichromatic phosphors. Increasing the rotational speed could cause the changes of SA, structural defects, and breakage of the crystalline network, which could significantly improve in REE extraction rates. Specifically, changes in the crystalline degree of disorder caused by mechanical activation played a crucial role in enhancing the REE leachability from waste trichromatic phosphors. In addition, the sulfuric acid leaching behaviors of the activated waste trichromatic phosphors were studied by varying several parameters, including leaching time, liquid-to-solid ratio, acid concentration, heating temperature, and various activation conditions: Y, Eu, and Ce recovery rates reached approximately 96.3%, 91.1%, and 77.3%, respectively, from waste trichromatic phosphors activated for 60 min at the rotational speed of 550 rpm (by ball mill) compared with 46.7%, 42.3%, and 31.2%, respectively, from the raw sample. The method is promising to be put into practice to promote the recycling REE from various waste electric and electronic products. [ABSTRACT FROM AUTHOR]

An abstract of the article "Mediator Influences Telomeric Silencing and Cellular Life Span," by Xuefeng Zhu, Beidong Liu, Jonas O.P. Carlstein, Jenny Beve, Thomas Nystrõm, Lawrence C. Myers and Claes M. Gustafsson, is presented.

Catalytic membrane reactors have the advantages of allowing the selective removal of products, avoiding the separation procedure of powder catalysts from the reaction mixture, intensifying the diffusion of reactants in the catalytic region, and integrating different reactions in one unit. Catalytic membrane reactors have been widely applied in the fields related to carbon peaking and carbon neutrality, including the capture and utilization of carbon dioxide, hydrogen production, and hydrogenation reaction. This review summarizes the design and fabrication of catalytic membrane reactors, with the focus on the capture and efficient utilization of carbon dioxide, hydrogen production and efficient liquid-phase hydrogenation. The design of membrane materials, catalyst materials and catalytic membranes, and the operation of catalytic membrane reactors are discussed respectively. Finally, the perspectives and future challenges of catalytic membrane reactors for carbon peaking and carbon neutrality are forecasted. [ABSTRACT FROM AUTHOR]

The article offers information about the oxygen activation on Ba-containing perovskite materials . It mentions that Oxygen activation, including oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) as important energy conversion processes. It discusses the activation mechanism of Ba-containing perovskite materials.

The multiprotein Mediator complex is an important regulator of RNA polymerase II-dependent genes in eukaryotic cells. In contrast to the situation in many other eukaryotes, the conserved Med15 protein is not a stable component of Mediator isolated from fission yeast. We here demonstrate that Med15 exists in a protein complex together with Hrp1, a CHD1 ATP-dependent chromatin-remodeling protein. The Med15-Hrp1 subcomplex is not a component of the core Mediator complex but can interact with the L-Mediator conformation. Deletion of med15+ and hrp1+ causes very similar effects on global steady-state levels of mRNA, and genome-wide analyses demonstrate that Med15 associates with a distinct subset of Hrp1-bound gene promoters. Our findings therefore indicate that Mediator may directly influence histone density at regulated promoters. [ABSTRACT FROM AUTHOR]

We report the experimental realization of an acoustic Chern insulator (ACI), by using an angular-momentum-biased resonator array with the broken Lorentz reciprocity. High Q-factor resonance of the constituent rotors is leveraged to reduce the required rotation speed. ACI is a new topological acoustic system analogous to the electronic quantum Hall insulator, based on an effective magnetic field. Experimental results show that the ACI featured with a stable and uniform metafluid flow bias supports one-way nonreciprocal transport of sound at its edges, which is topologically immune to various types of defects. Our work opens up opportunities for exploring unique observable topological phases and developing topological-insulator-based nonreciprocal devices in acoustics. [ABSTRACT FROM AUTHOR]

By using optical phase modulators in a fiber-optical circuit, we theoretically and experimentally demonstrate large control over the spectrum of an impinging signal, which may evolve analogously to discrete diffraction in spatial waveguide arrays. The modulation phase acts as a photonic gauge potential in the frequency dimension, realizing efficient control of the central frequency and bandwidth of frequency combs. We experimentally achieve a 50 GHz frequency shift and threefold bandwidth expansion of an impinging comb, as well as the frequency analogue of various refraction phenomena, including negative refraction and perfect focusing in the frequency domain, both for discrete and continuous incident spectra. Our study paves a promising way towards versatile frequency management for optical communications and signal processing using time modulation schemes. [ABSTRACT FROM AUTHOR]