The addressing of passive matrix LCDs is well known, with predefined voltages being applied to both rows and columns during an update. In this paper we present a novel method of driving a Zenithal ...Bistable LCD, applying a high impedance state to inactive rows and/or columns. Significant improvements in power consumption are demonstrated.
In bacteria, σ28 is the flagella‐specific sigma factor that targets RNA polymerase (RNAP) to control the expression of flagella‐related genes involving bacterial motility and chemotaxis. However, the ...structural mechanism of σ28‐dependent promoter recognition remains uncharacterized. Here, we report cryo‐EM structures of E. coli σ28‐dependent transcribing complexes on a complete flagella‐specific promoter. These structures reveal how σ28‐RNAP recognizes promoter DNA through strong interactions with the −10 element, but weak contacts with the −35 element, to initiate transcription. In addition, we observed a distinct architecture in which the β′ zinc‐binding domain (ZBD) of RNAP stretches out from its canonical position to interact with the upstream non‐template strand. Further in vitro and in vivo assays demonstrate that this interaction has the overall effect of facilitating closed‐to‐open isomerization of the RNAP–promoter complex by compensating for the weak interaction between σ4 and −35 element. This suggests that ZBD relocation may be a general mechanism employed by σ70 family factors to enhance transcription from promoters with weak σ4/−35 element interactions.
Synopsis
Cryo‐EM structures of a σ28‐transcription initiation complex (TIC) reveal a novel role of β′ bacterial RNA polymerase (RNAP) zinc‐binding domain (ZBD) in transcription initiation. Relocation of the ZBD may compensate for weak σ4/−35 element interactions and hereby enhance transcription from this type of promoters.
Cryo‐EM reconstructions of σ28‐TIC at 3.86 Å (state 1) and 3.91 Å (state 2) define the specific promoter recognition by σ28.
Cryo‐EM structure of state‐2 σ28‐TIC reveals a distinct architecture of β′ zinc binding domain of RNAP.
ZBD relocation has an overall effect of facilitating the isomerization of
RNAP‐promoter closed to open complex to enhance transcription.
ZBD relocation could be exploited by the σ70‐family factors to enhance
Transcription by compensating for the weak interaction between σ4 and promoter −35 element.
Cryo‐EM studies of the E. coli σ28‐RNA polymerase complex recognizing a flagellar promoter sequence identifies conformational transitions that promote transcription from a weak promoter.
The arthropod‐transmitted chikungunya virus has emerged as an epidemic menace that causes debilitating polyarthritis. With this life‐threatening impact on humans, the possible treatment requires to ...cure the viral infectivity. But, devoid of any vaccine against the chikungunya virus (CHIKV), there is a need to develop a novel chemotherapeutic strategy to treat this noxious infection. CHIKV carries highly compact P23pro‐zbd structure that possesses potential RNA‐binding surface domains which extremely influences the use of RNA template during genome replication at the time of infection and pathogenesis. Therefore, computational approaches were used to explore the novel small molecule inhibitors targeting P23pro‐zbd domain. The tertiary structure was modeled and optimized using in silico approaches. The results obtained from PROCHECK (93.1% residues in favored regions), ERRAT (87.480 overall model quality) and ProSA (Z‐score: −11.72) revealed the reliability of the proposed model. Interestingly, a previously reported inhibitor, chloroquine possesses good binding affinities with the target domain. In‐depth analysis revealed that chloroquine derivatives such as didesethyl chloroquine hydroxyacetamide, cletoquine, hydroxychloroquine exhibited a better binding affinity. Notably, MD simulation analysis exhibited that Thr1312, Ala1355, Ala1356, Asn1357, Asp1364, Val1366, Cys1367, Ala1401, Gly1403, Ser1443, Tyr1444, Gly1445, Asn1459, and Thr1463 residues are the key amino acid responsible for stable ligand‐protein interaction. The results obtained from this study provide new insights and advances the understanding to develop a new approach to consider effective and novel drug against chikungunya. However, a detailed in vivo study is required to explore its drug likeliness against this life‐threatening disease.
The amino acid residues Ala1356, Gly1403, and Ser1443 at the active site of the homology model of P23pro‐zbd domain of Chikungunya virus crucially interact with chloroquine derivative compound didesethyl chloroquine hydroxyacetamide.
Deliberate manipulation of topological defects is of particular interest for liquid crystal applications. For example, surface bistability occurs in the grating aligned Zenithal Bistable Device due ...to the stabilisation of ±½ defects at the points of high surface curvature. Conventional latching between continuous and defect states has previously been simulated satisfactorily using Q-tensor models that include the effect of weak-anchoring and flexoelectricity. However, experimental studies show that some arrangements lead to anomalous latching regimes. The Q-tensor model is used to show that such effects occur when the defects become detached from the surface and have more complex paths in the bulk of the sample.
The United Kingdom has a proud history of liquid crystal research. Its contributions span from the formulation of the theory of nematic elasticity as it is used today, uncovered via the ...Leslie–Erickson theory describing the viscosity of mesophases, to the discovery of the first room-temperature nematic and the related developments in the display industry, to name just several pioneering contributions. Today, liquid crystal science in the UK is more diverse and multidisciplinary than ever, ranging from the synthesis of increasingly complex mesogenic molecules, via the physical properties of self-organised systems and composites of both the thermotropic and the lyotropic type, to a wide variety of applications outside of the traditional display sector. The field covers aspects of chemistry, physics, material sciences, chemical engineering, mathematics, biology and device engineering in an overarching effort to advance the fundamental understanding of these soft-matter materials and to promote their technological exploitation in the UK and worldwide. To this end, a large group of individuals and research groups from universities and industry in the UK are working together on a Special Issue to advance the development of this field. The achievements of these scholars can be found in publications in top-class journals and presentations at all large international conferences, in the development of new products, and in events for public engagement.
Summary
Traumatic spinal cord injury (SCI) happens accidently and often leads to motor dysfunction due to a series of biochemical and pathological events and damage, either temporarily or ...permanently. Translocator protein 18 (TSPO) has been found to be involved in the synthesis of endogenous neurosteroids which have multiple effects on neurons, but the internal mechanisms are not clear. N‐benzyl‐N‐ethyl‐2‐(7,8‐oxo‐2‐phenyl‐9H‐purin‐9‐yl) acetamide (ZBD‐2), a newly reported ligand of TSPO, shows some neuroprotective effect against focal cerebral ischemia in vivo and NMDA‐induced neurotoxicity in vitro. The present study aims to examine the role of ZBD‐2 in SCI mice and elucidate the underlying molecular mechanisms. The SCI model was established by crushing spinal cord. ZBD‐2 (10 mg/kg) significantly enhanced the hindlimb locomotor functions after SCI and decreased the tissue damage and conserved the white matter of the spinal cord. High‐dose ZBD‐2 alleviated the oxidative stress induced by SCI and regulated the imbalance between NR2B‐containing NMDA and GABA receptors by increasing the levels of GAD67 in the spinal cord of SCI mice. Additionally, ZBD‐2 (10 mg/kg) increased phosphorylated Akt (p‐Akt) and decreased the ratio of Bax/Bcl‐2. These results demonstrate that ZBD‐2 performs neuroprotection against SCI through regulating the synaptic transmission and the PI3K/AKT signaling pathway.
The Terahertz frequency range (0.1 – 10)THz has demonstrated to provide many opportunities in prominent research fields such as high-speed communications, biomedicine, sensing, and imaging. This ...spectral range, lying between electronics and photonics, has been historically known as “terahertz gap” because of the lack of experimental as well as fabrication technologies. However, many efforts are now being carried out worldwide in order improve technology working at this frequency range. This book represents a mechanism to highlight some of the work being done within this range of the electromagnetic spectrum. The topics covered include non-destructive testing, teraherz imaging and sensing, among others.
This paper presents and discusses the careful modeling of a Zero Biased Diode, including low-frequency noise sources, providing a global model compatible with both wire bonding and flip-chip ...attachment techniques. The model is intended to cover from DC up to W-band behavior, and is based on DC, capacitance versus voltage, as well as scattering and power sweep harmonics measurements. Intensive use of 3D EM (ElectroMagnetic) simulation tools, such as HFSSTM, was done to support Zero Biased Diode parasitics modeling and microstrip board modeling. Measurements are compared with simulations and discussed. The models will provide useful support for detector designs in the W-band.
A reported is presented on the first communication system using vectorial modulation schemes above 500 GHz. Using Schottky‐based electronic technologies at 588 GHz, potentialities of high‐level ...multi‐carrier modulation schemes for wireless links are analysed. The wireless link is composed of an emitter with a sub‐harmonic mixer for up‐conversion from 294 to 588 GHz and carrier modulation. A pumped zero‐bias detector is used at reception. Mono‐carrier signalling is realised using an up to 32‐symbol modulation scheme and multi‐carrier terahertz transmission is also achieved using several modulation schemes in parallel.
— The first commercial use of the Zenithal Bistable Display (ZBD™) is for electronic point‐of‐purchase (epop™) signage in the retail sector. As a reflective bistable display, this novel LCD ...technology only consumes power if new information is required and the image is updated. This allows complex images to be shown constantly for several years from the energy of a single low‐cost battery, when the display is updated up to ten times each day — ideal for signage applications. Excellent performance characteristics are achieved in a TN‐like STN‐LCD in which one of the alignment surfaces is a relief grating. Correct design of the grating shape and surface properties not only imparts the bistability, but allows control of the optical performance, the latching voltages, and the temperature range. Being addressed using a simple passive‐matrix approach, without the need for a thin‐film‐transistor backplane, large amounts of information may be displayed by STN drivers. Alow‐cost fabrication method has been devised that is compatible with conventional TN and STN manufacture, and with negligible equipment outlay. The device operating principles, manufacturing method, and performance of ZBDs are reviewed.
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