Reversible Step Research Articles

The effect of positive and reverse current cycles on the wettability, morphology, and corrosion behaviour of electrodeposited nickel matrix layer

ABSTRACT In this study, Ni-TiO2 coatings were formed using a multi-step pulse method with positive and, in some cases, reverse current steps. All coatings were produced at a current density of 4 A dm−2 and a frequency and duty cycle of 10 Hz and 10%, respectively with a thickness of 30 µm. The results showed that by applying the reverse current cycle, the codeposition of TiO2 particles in the coating decreased and the morphology of the coating became irregular. It was found that the effect of the wetting angle of the coating is greater than the incorporation of TiO2 particles on the corrosion behaviour of the coating. Thus, a coating was created with a positive 4-step pulse current with the lowest amount of TiO2 particles (7.7 vol.%) having the highest resistance against corrosion. The sample had compact morphology and high wetting angle (82.61o֯).

α,β‐C—C—C Agostic Bonding Interactions in Ruthenacyclobutane and π‐Complex Assisted Olefin Metathesis Catalyzed by Ruthenium‐Alkylidene Complexes

ABSTRACTComputational aspects of concerted [2+2] oxidative‐retrocycloaddition‐cycloreversion reaction through ruthenium alkylidene π‐complexes and ruthenacyclobutane with α,β‐(C—C—C) agostic bonding interactions in olefin metathesis are presented. d6‐Ruthenium carbene complexes, with ruthenium in the oxidation state +2, undergo successive [2+2] cycloaddition and cycloreversion steps, through associative, dissociative, or interchange mechanisms. This process involves coordination of the olefin to 16‐electron Ru complex followed by phosphine dissociation, or first phosphine dissociation then coordination of the olefin to the 14‐electron Ru complex with rearrangement to a ruthenacyclobutane intermediate, followed by symmetrical reverse steps. Donation of σ‐electron density from the two C—C σ‐bonds to the metal center leads to α,β‐(C—C—C) agostic bonds, which stabilized metallacyclobutane as a formally 16‐electron complex, with lower energy than the corresponding π‐complex. In the transformation from π‐complex to ruthenacyclobutane the ruthenium atom is formally oxidized to Ru(IV). The most efficient ligands are those that stabilize the high‐oxidation state metallacyclobutane (IV) intermediate relative to the ruthenium carbene.

Lubrication flow law and cooling mechanism considering cavitation in mechanical seals with Rayleigh step pattern

The purpose of this research is to obtain the cavitation cooling characteristics and flow law in mechanical seals with Rayleigh step pattern. A new cooling approach has been proposed, which is of great significance to preventing liquid film vaporization and limiting thermal deformation of sealing face. Based on the previous literatures focused only on cavitation or viscous heat, the thermohydrodynamic lubrication (THD) and hydrodynamic lubrication (HD) numerical models with cavitation in mechanical seals are developed to obtain the cavitation cooling characteristics and flow mechanism by FLUENT software. The results show that the liquid film cavitation occurs severely in the reverse Rayleigh step and generates a remarkable local cooling effect to the fluid film and sealing faces, which leads to a temperature rise reduction of up to 39.2% and a leakage rate reduction of up to 72.7%. Meanwhile, the high-temperature zone at downstream side migrates upstream, especially, forming temperature valley and peak zones at liquid film rupture and reformation boundaries. The cooling level is controlled by the intensity and area of cavitation. Moreover, the vapor phase block of cavitation, the pressure flow and the shear flow collectively generate a vortex flow behind the cavitation zone in the reverse Rayleigh step. The center and intensity of vortices are closely related to the cavitation area, viscous heat, shear flow and pressure flow. Under THD conditions, the vortex is enhanced due to the viscosity loss and the small cavitation area. The cavitation, viscous heat and vortex flow have important effects on the sealing performance.

Petrogenesis of the Deccan high-Mg basalts and picrites

Tholeiitic basalts and picrites from the Deccan Traps were used to constrain the pressure and temperature conditions of mantle melting for their origin. Clinopyroxene thermobarometry indicates that all Deccan tholeiites crystallized at low pressures in the upper crust (< 6 kbar/1047–1221 °C). In comparison, the Deccan alkalic rocks crystallized at pressures up to ~ 12.7 kbar. Rare samples of the tholeiites plot on their low-pressure olivine-plagioclase-clinopyroxene (Ol-Pl-Cpx) cotectic boundaries or olivine control lines in phase diagrams. These samples represent unmodified magmatic liquids. Primary magmas of the basalts that plot on their cotectic boundaries were modeled through reverse fractionation by incrementally adding equilibrium Ol + Pl + Cpx, Ol + Pl and Ol ± spinel, until the liquid was multiply saturated with lherzolite at a high pressure. The high-Mg basalts are contaminated with continental crust. Hence, a crustal partial melt was simultaneously subtracted according to energy constraints at each reverse fractionation step for these samples. The results show that the high-Mg basalts are 41–53% fractionated and 1–6% contaminated, and the low-Mg basalts are 63–67% fractionated. Their primary magmas were last equilibrated with spinel lherzolite at 10–13 kbar/1289–1333 °C. A picrite and two very high-Mg basalts plot on their olivine control lines. So, their primary magmas were calculated by adding only equilibrium olivine. These samples are 9–25% fractionated, and their primary magmas were last equilibrated with garnet lherzolite at 25–36 kbar/1452–1531 °C. The estimated mantle potential temperatures are 1400–1500 °C for the Deccan tholeiites, consistent with their origin from a mantle plume.

CRISPR/Cas13a analysis based on NASBA amplification for norovirus detection

Human norovirus (HuNoV) is a leading cause of foodborne diseases worldwide, making rapid and accurate detection crucial for prevention and control. In recent years, the CRISPR/Cas13a system, known for its single-base resolution in RNA recognition and unique collateral cleavage activity, is particularly suitable for sensitive and rapid RNA detection. However, isothermal amplification-based CRISPR/Cas13 assays often require an external transcription step, complicating the detection process. In our study, an efficient diagnostic technique based on the NASBA/Cas13a system was established to identify conserved regions at the ORF1-ORF2 junction of norovirus. The RNA amplification techniques [Nucleic Acid Sequence-Based Amplification (NASBA)] integrates reverse transcription and transcription steps, enabling sensitive, accurate, and rapid enrichment of low-abundance RNA. Furthermore, the CRISPR/Cas13a system provides secondary precise recognition of the amplified products, generating a fluorescence signal through its activated accessory collateral cleavage activity. We optimized the reaction kinetics parameters of Cas13a and achieved a detection limit as low as 51pM. The conditions for the cascade reaction involving CRISPR analysis and RNA amplification were optimized. Finally, we validated the reliability and accuracy of the NASBA/Cas13a method by detecting norovirus in shellfish, achieving results comparable to qRT-PCR in a shorter time and detecting viral loads as low as 10 copies/μL.

Adsorption-controlled electrochemical reaction with reversible dimerization, coupled to a preceding chemical reaction on porous graphenic surface: Modelling and application in label-free capacitive biosensing

Electrokinetic modelling and experimental studies are conducted on an adsorption system, with a model redox-active adsorbate 3,3′,5,5′-tetramethylbenzidine (TMB), strongly adsorbed to a platinum nanoparticle (PtNP)-modified porous laser induced graphene (LIG) surface. The adsorption-assisted system defined here involves an electrochemical reaction coupled to a preceding, surface-bound, chemical oxidation of the adsorbate. TMB is also known to undergo intermediate reversible dimerization during oxidation. A shift in the general expressions governing the voltammetric trends due to this reversible dimerization step, and the associated impact on the electrokinetic parameters is presented here for the first time. Impedance analysis reveals a modified Randles circuit, with the faradaic contribution of the adsorbate represented by a CPE circuit component. The adsorption-associated phasance, Qads, is expressed as a function of the surface concentrations, ΓO and ΓR, of the oxidised and reduced forms. Changes in the total surface concentration of the adsorbate, Γm, as a result of the presence of localised non-conductive entities, such as proteins, can be correlated to Qads, and subsequently, this capacitive change can be utilised for affinity sensing of an antigen on a specific immunosurface. Proof of concept is carried out with the immunosensing of a model protein, rheumatoid factor, on a PtNP-modified LIG surface biofunctionalised with the specific capture probe, the Fc fragment of IgG. The relationship between the antigenic concentration CRF, Qads and Γm is established. This label-free, adsorption-assisted, capacitive biosensing mechanism has not be reported previously, to the best of our knowledge, with a linear range of 0–300 U mL−1 and an LOD of 0.515 U mL−1 in spiked serum samples, comparable to the gold standard, ELISA.

Stereoelectrochemistry of Tetranitrocalix[4]arenes

The present article reveals the differences in voltammetric reduction curves of isomeric nitrocalix[4]arenes (a kind of their “fingerprints”). This observation represents a contribution to a newly introduced utilization of electrochemical approach called “stereoelectro­chemistry” and extends the knowledge on these polycyclic molecules. In stereoelectrochemistry, the electrochemical data (potentials and their shifts, number of individual redox steps, proportions of their currents, reversibility etc.) in correlation with a series of derivatives can offer important information concerning the shape, geometry, conformation and static/dynamic behaviour of studied molecules in solution. Four possible atropoisomers of para-tetranitrocalix[4]arene were investigated by DC polarography and cyclic voltammetry in aprotic media (anhydrous N,N-dimethylformamide). Under such conditions, a typical reduction mechanism of a nitro compound involves a reversible single electron reduction step yielding an anion radical, followed by three-electron irreversible process assisted by protons (from moisture traces). While the already published most symmetric cone-conformer accepts first four electrons in two separated steps (which is in accordance with the “pinched” C2v shape of the molecule), the same behaviour was observed also in the case of 1,3-alt-derivative, the equilibrium geometry of which was predicted to be highly symmetric (S4), with no distinction among the nitro substituents. Hence, the 1,3-alt-molecule must oscillate around the equilibrium geometry (slower than the time scale of electron transfer) to produce a pinched limiting geometry with two different pairs of nitro groups (distal and proximal). The paco-derivative (and also its dinitro analogue) is reduced in three steps, during which the “tilted” aromatic unit is reduced first, followed by the opposite one (distal), and eventually another pair of proximal nitro groups (equivalent) is reduced simultaneously. The least symmetric 1,2-alt-compound (C1) is reduced in four single-electron, difficultly resolved steps due to small differences in the individual nitro groups energy.

GSH-responsive and folate receptor-targeted pyridine bisfolate-encapsulated chitosan nanoparticles for enhanced intracellular drug delivery in MCF−7 cells

Folic acid receptor-targeted drug delivery system is a promising candidate for tumor-targeted delivery because its elevated expression specifically on tumor cells enables the selective delivery of cytotoxic cargo to cancerous tissue, thereby minimizing toxic side effects and increasing the therapeutic index. Pyridine bisfolate-chitosan (PyBFA@CS NPs) and folate-chitosan nanocomposite (FA@CS NPs) were synthesized with suitable particle size (256.0 ± 15.0 and 161.0 ± 5.0 nm), high stability (ζ = −27.0 ± 0.1 and −30.0 ± 0.2 mV), respectively, and satisfactory biocompatibility to target cells expressing folate receptors and try to answer the question: Is the metal center always important for activity? Since almost all pharmaceuticals work by binding to specific proteins or DNA, the in vitro binding of human serum albumin (HSA) to PyBFA@CS NPs and FA@CS NPs has been investigated and compared with PyBFA. Strong affinity to HSA is shown by quenching and binding constants in the range of 105 and 104 M−1, respectively with PyBFA@CS NPs showing the strongest. The compounds-HSA kinetic stability, affinity, and association constants were investigated using a stopped-flow method. The findings showed that all formulations bind by a static quenching mechanism that consists of two reversible steps: rapid second-order binding and a more slowly first-order isomerization reaction. The overall coordination affinity of HSA to PyBFA@CS NPs (6.6 × 106 M−1), PyBFA (4.4 × 106 M−1), and FA@CS NPs (1.3 × 106 M−1) was measured and The relative reactivity is roughly (PyBFA@CS NPs)/(PyBFA)/(FA@CS NPs) = 5/3/1. Additionally, in vitro cytotoxicity revealed that, consistent with the binding constants and coordination affinity, active-targeting formulations greatly inhibited FR-positive MCF-7 cells in compared to FRs-negative A549 cells in the following trend: PyBFA@CS NPs > PyBFA > FA@CS NPs. Furthermore, in vitro drug release of PyBFA@CS NPs was found to be stable in PBS at pH 7.4, however, the in pH 5.4 and in pH 5.4 containing 10 mM glutathione (GSH) (mimicking the tumor microenvironment) reached 43 % and 73 %, respectively indicating that the PyBFA@CS NPs system is sensitive to GSH. Folate-modified nanoparticles, PyBFA@CS NPs, are a promising therapeutic for MCF-7 therapy because they not only showed a greater affinity for HSA, but also showed higher cleavage efficiency toward the minor groove of pBR322 DNA via the hydrolytic way, as well as effective antibacterial activity that avoids the usage of extra antibiotics.‬‬‬‬‬‬‬‬‬‬‬‬ ‬‬‬‬‬‬‬‬‬‬‬‬‬‬

Penggunaan Metode Quantitative Polymerase Chain Reaction (qPCR) untuk Deteksi Fragmen DNA Babi pada Produk Olahan Daging

Using food ingredients and/or processed food products contaminated with pork, whether unintentionally or intentionally, has become a growing concern and issue. This condition encourages the development of an accurate method for specifically detecting the presence or absence of pork contamination. The research was carried out on two different samples: (1) fresh pork to provide an in-house positive control and (2) samples of pork-based processed meat products (floss, meatballs, corned beef, and sausages), tested using DNA markers. The use of samples originating from processed pork food is to determine the effect of the processing process on DNA fragments and the robustness of the extraction method for the detection process used. The research aimed to detect pork DNA fragments using the quantitative polymerase chain reaction (qPCR) method. The study stages were extracting fresh pork and processed products using an RNA extraction kit, DNA extraction kit, and salt extraction, as well as measuring the purity and concentration of DNA/RNA using a spectrophotometer. The RNA extract was converted into complementary DNA (cDNA), and the DNA extract was analyzed using qPCR with specific primers for pork DNA (Sus scrofa). The results showed that the concentration of RNA and DNA extracts was 71.1–296.025 ng/uL and of various purity. All processed meat product samples and in-house positive controls were amplified in the Ct range of 23–28 ng/uL. In this case, the meat processing had no effect on the DNA of the processed meat products analyzed, so DNA fragments could be detected. DNA qPCR was more time efficient than cDNA qPCR because it did not require an RNA reverse transcription step. Keywords: beta actin, cycle threshold, fresh pork, pork DNA, qPCR

Multi-Modal Modality-Masked Diffusion Network for Brain MRI Synthesis With Random Modality Missing.

Synthesis of unavailable imaging modalities from available ones can generate modality-specific complementary information and enable multi-modality based medical images diagnosis or treatment. Existing generative methods for medical image synthesis are usually based on cross-modal translation between acquired and missing modalities. These methods are usually dedicated to specific missing modality and perform synthesis in one shot, which cannot deal with varying number of missing modalities flexibly and construct the mapping across modalities effectively. To address the above issues, in this paper, we propose a unified Multi-modal Modality-masked Diffusion Network (M2DN), tackling multi-modal synthesis from the perspective of "progressive whole-modality inpainting", instead of "cross-modal translation". Specifically, our M2DN considers the missing modalities as random noise and takes all the modalities as a unity in each reverse diffusion step. The proposed joint synthesis scheme performs synthesis for the missing modalities and self-reconstruction for the available ones, which not only enables synthesis for arbitrary missing scenarios, but also facilitates the construction of common latent space and enhances the model representation ability. Besides, we introduce a modality-mask scheme to encode availability status of each incoming modality explicitly in a binary mask, which is adopted as condition for the diffusion model to further enhance the synthesis performance of our M2DN for arbitrary missing scenarios. We carry out experiments on two public brain MRI datasets for synthesis and downstream segmentation tasks. Experimental results demonstrate that our M2DN outperforms the state-of-the-art models significantly and shows great generalizability for arbitrary missing modalities.

Investigation of remeshing parameters for deviation analysis in reverse engineering

The use of additive manufacturing technologies in industry is increasingly common, particularly with the emergence of Industry 4.0. These technologies can produce parts quickly and efficiently, but they also place higher demands on the quality of the manufactured products. The layer-by-layer processes create an anisotropic material model, which complicates component sizing. While the topic has been extensively researched, surface anisotropy has received less attention. The surface quality of a product may be affected by various factors, including the file conversion process or the staircase effect generated by the technology. Manufacturing parameters, such as layer thickness and orientation, can also have an impact. This paper focuses on the impact of reverse engineering step adjustment on surface quality.

Association of inflammatory markers and ultrasonographic indicators of endothelial (dys)function in humans

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The Austrian Science Fund (FWF) Introduction It has been widely known that chronic inflammation is a crucial factor in the process of atherogenesis and atherosclerosis. Also, endothelial dysfunction presents the first and still reversible step of that process.(1) It is a challenge to find a laboratory marker whose levels would be informative about the extent of endothelial dysfunction and atherogenesis in humans. Purpose The aim of the present study was to determine associations between markers of chronic, low-grade inflammation and ultrasonographic indicators of endothelial (dys)function in healthy volunteers (H) and in patients with metabolic syndrome (MS). Methods Any kind of clinically manifest acute inflammatory or infectious disease, as well as chronic inflammatory, autoimmune or malignant disease was an exclusion criterion for participation. Serum levels of C-reactive protein (CRP) were measured using standard clinical chemistry analyser, and serum levels of interleukin-6 (IL-6) using electro-chemiluminescence immunoassay. Blood vessel wall function was quantified as flow-mediated dilation (FMD) and nitroglycerin-mediated dilation (NMD), which were measured automatically and continuously using the ultrasound device with linear probe (10 MHz) and the software for ultrasound blood vessel diameter analysis,(2) following currently valid guidelines.(3,4,5) Results A total of 130 individuals were enrolled in the study (65 H and 65 MS), with a median age of 56 (IQR 50.0, 60.0) years and 47.7% women in each group. CRP and IL-6 levels, although being very low and within the intervals that are considered normal in everyday clinical practice for both groups [CRP - H: 1.2 (0.6, 2.3), MS: 2.4 (1.2, 5.5) μg/mL; IL-6 - H: 2.3 (1.7, 3.0), MS: 4.1 (2.7, 6.8) pg/mL], were significantly higher in the MS compared to H (both p&amp;lt;0.001). The MS group also had significantly lower FMD (p=0.013) and NMD (p=0.033) compared to H. In H, IL-6 levels were significantly negatively correlated with FMD (r=-0.46, p&amp;lt;0.001), but not with NMD; whereas no significant associations of IL-6 levels with FMD or NMD were observed in the MS group. CRP levels were not significantly associated with FMD or NMD in neither the H nor MS group. Conclusion Higher IL-6 serum levels in the absence of acute inflammatory or infectious disease are significantly associated with lower FMD values among individuals with low risk for cardiovascular diseases, who are still considered healthy. Direct correlation is attenuated and lost among individuals with developed clinical signs of metabolic syndrome, probably due to its complex pathophysiology, as well as redundant and interdependent mechanisms contributing to the occurrence of endothelial dysfunction in such an environment. Further investigation on larger cohorts is needed to determine whether IL-6 serum levels could serve as a marker of endothelial dysfunction in individuals without clinically developed traditional risk factors and symptoms of cardiovascular disease.

Step Vulnerability Guided Mean Fluctuation Adversarial Attack against Conditional Diffusion Models

The high-quality generation results of conditional diffusion models have brought about concerns regarding privacy and copyright issues. As a possible technique for preventing the abuse of diffusion models, the adversarial attack against diffusion models has attracted academic attention recently. In this work, utilizing the phenomenon that diffusion models are highly sensitive to the mean value of the input noise, we propose the Mean Fluctuation Attack (MFA) to introduce mean fluctuations by shifting the mean values of the estimated noises during the reverse process. In addition, we reveal that the vulnerability of different reverse steps against adversarial attacks actually varies significantly. By modeling the step vulnerability and using it as guidance to sample the target steps for generating adversarial examples, the effectiveness of adversarial attacks can be substantially enhanced. Extensive experiments show that our algorithm can steadily cause the mean shift of the predicted noises so as to disrupt the entire reverse generation process and degrade the generation results significantly. We also demonstrate that the step vulnerability is intrinsic to the reverse process by verifying its effectiveness in an attack method other than MFA. Code and Supplementary is available at https://github.com/yuhongwei22/MFA

Abstract 3760: The importance of optimizing DNA extraction conditions for formalin fixed paraffin embedded tissues

Abstract The pre-analytic extraction of Formalin Fixed Paraffin Embedded Tissues (FFPETs) appears to have a profound effect on the ability to obtain meaningful data from the DNA therein. FFPETs represent important materials in Pathology that are used to diagnose and analyze cancer. As part of preparing FFPETs, the formalin fixation step preserves the structure of tissues through covalent modifications but can also damage nucleic acids through that same process. Over the last decade, the emergence of Molecular Pathology, which benefits from gentler fixation compared to Histopathology and especially Immunohistopathology, has led to changes in how FFPETs are prepared. However, the remnant FFPETs from over a decade ago may be far from representative of what is now prepared for Molecular Pathology by many laboratories. Here we discuss our optimization of FFPET extraction for gently fixed samples. When we prepared our Seraseq FFPE Homologous Recombination Deficiency (HRD) reference standards using fixation conditions that are recommended for Molecular Pathology and extracted the resulting FFPETs using generic conditions, our initial coverage data from Whole Genome Shotgun (WGS) sequencing was difficult to analyze for changes in copy number across the genome. A major contributor to nonuniform coverage was identified as the formalin reversal step, where deparaffinized proteinase K-digested tissue is heated in water to near boiling to attempt to detach formaldehyde from nucleic acids through hydrolysis. Given the gentler fixation conditions, this step was found to be mostly unnecessary, and omitting it improved the resulting data substantially. A reason for this appears to be that the gentler fixation conditions that are now in use may not protect the DNA from the effects of near-boiling water, where the lack of salt lowers the melting temperature of double stranded DNA fragments and causes them to denature unless they have a higher GC content. Different kits used for the extraction of nucleic acids from FFPETs may benefit from different optimizations to obtain improved sequencing data from today’s Molecular pathology samples, and reference standards that represent such samples provide a useful tool for such optimizations. Citation Format: Matthew G. Butler, Benedicta Forson, Maria Cowen, Jayanthi Ramprakash, Dana Ruminski Lowe, Yves Konigshofer. The importance of optimizing DNA extraction conditions for formalin fixed paraffin embedded tissues [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3760.

Automatic berthing of unmanned surface vessels with predetermined performance

To solve the problem of ship automatic berthing control due to unknown time-varying disturbance and dynamic uncertainty of model parameters, an automatic berthing control law based on predefined performance time function is proposed. First, a predefined performance time function is designed and coupled with tracking error to achieve the predetermined performance of tracking error. Secondly, radial basis function neural network is used to approach the dynamic uncertainty of ship model parameters, and the complex uncertainty of model parameters and unknown time-varying disturbance is represented by linearized parameter form with single virtual parameter, which makes the calculation simple and easy to implement in engineering. On this basis, the reverse step control law is designed. Thirdly, the stability of the system is proved based on Lyapunov stability theory. Finally, the simulation results show that the control law can make the ship reach the desired position and heading angle, and realize the automatic berthing of the ship. The control law and berthing controller designed in this paper have good applicability and robustness, which provides a theoretical basis for the subsequent control research of surface intelligent ships.

Linear-Extended-State-Observer-Based Adaptive RISE Control for the Wrist Joints of Manipulators with Electro-Hydraulic Servo Systems

Manipulators are multi-rigid-body systems composed of multiple moving joints. During movement, the Coriolis force, centrifugal force, and gravity of the system undergo significant changes. The last three degrees of freedom (DOFs) of the wrist joint of a manipulator control the end attitude. Improving the command tracking accuracy of the wrist joint is a key challenge in controlling the end attitude of manipulators. In this study, a dynamics model of the mechanical arm–wrist joint is established based on the Lagrange method. An adaptive continuous robust integral of the sign of the error (ARISE) controller is designed using the reverse step method. Additionally, a linear extended state observer (LESO) is employed to estimate the time-varying interference existing in the system and compensate for it in the designed control rate. The stability of the Lyapunov function and the boundedness of the observer are proven. The proposed control method for the wrist joint is compared with other controllers on an experimental platform of multi-DOF hydraulic manipulators. The results demonstrate that the proposed method improves the control performance of hydraulic manipulators. The application of this method offers a new strategy and idea for achieving high-performance tracking control in hydraulic manipulators.

Classic human astrovirus 4, 8, MLB-3, and likely new genotype 5 sublineage in stool samples of children in Nigeria.

Human astrovirus (HAstV) is a nonenveloped RNA virus and has been implicated in acute gastroenteritis among children and elderly. However, there exists a substantial dearth of information on HAstV strains circulating in Nigeria. Viral-like particles were purified from archived 254 stool samples of children with acute flaccid paralysis between January and December 2020 from five states in Nigeria, using the NetoVIR protocol. Extracted viral RNA and DNA were subjected to a reverse transcription step and subsequent random polymerase chain reaction amplification. Library preparation and Illumina sequencing were performed. Using the virome paired-end reads pipeline, raw reads were processed into genomic contigs. Phylogenetic and pairwise identity analysis of the recovered HAstV genomes was performed. Six near-complete genome sequences of HAstV were identified and classified as HAstV4 (n = 1), HAstV5 (n = 1), HAstV8 (n = 1), and MLB-3 (n = 3). The HAstV5 belonged to a yet unclassified sublineage, which we tentatively named HAstV-5d. Phylogenetic analysis of open reading frames 1a, 1b, and 2 suggested recombination events inside the MAstV1 species. Furthermore, phylogenetic analysis implied a geographic linkage between the HAstV5 strain from this study with two strains from Cameroon across all the genomic regions. We report for the first time the circulation of HAstV genotypes 4, 8, and MLB-3 in Nigeria and present data suggestive for the existence of a new sublineage of HAstV5. To further understand the burden, diversity, and evolution of HAstV, increased research interest as well as robust HAstV surveillance in Nigeria is essential.

Analysis of Negative-Strand RNA Viruses by RT-qPCR: Rift Valley Fever Virus and Toscana Virus.

RT-qPCR allows the detection of viruses and the monitoring of viral replication. This technique was extensively employed during the SARS-CoV-2 pandemic, where it demonstrated its efficiency and robustness. Here we describe the analysis of Rift Valley fever and Toscana virus infections over time, achieved through the RT-qPCR quantification of the viral genome. We further elaborate on the method to discriminate between genomic and antigenomic viral RNAs by using primers specific for each strand during the reverse transcription step.

Direct RNA Sequencing of Foot-and-mouth Disease Virus Genome Using a Flongle on MinION.

Foot-and-mouth disease (FMD) is a severe and extremely contagious viral disease of cloven-hoofed domestic and wild animals, which leads to serious economic losses to the livestock industry globally. FMD is caused by the FMD virus (FMDV), a positive-strand RNA virus that belongs to the genus Aphthovirus, within the family Picornaviridae. Early detection and characterization of FMDV strains are key factors to control new outbreaks and prevent the spread of the disease. Here, we describe a direct RNA sequencing method using Oxford Nanopore Technology (ONT) Flongle flow cells on MinION Mk1C (or GridION) to characterize FMDV. This is a rapid, low cost, and easily deployed point of care (POC) method for a near real-time characterization of FMDV in endemic areas or outbreak investigation sites. Key features • Saves ~35 min of the original protocol time by omitting the reverse transcription step and lowers the costs of reagents and consumables. • Replaces the GridION flow cell from the original protocol with the Flongle, which saves ~90% on the flow cell cost. • Combines the NGS benchwork with a modified version of our African swine fever virus (ASFV) fast analysis pipeline to achieve FMDV characterization within minutes. Graphical overview Schematic of direct RNA sequencing of foot-and-mouth disease virus (FMDV) process, which takes ~50 min from extracted RNA to final loading, modified from the ONT SQK-RNA002 protocol (Version: DRS_9080_v2_revO_14Aug2019).

Tryptophan to Tryptophan Hole Hopping in an Azurin Construct.

Electron transfer (ET) between neutral and cationic tryptophan residues in the azurin construct [ReI(H126)(CO)3(dmp)](W124)(W122)CuI (dmp = 4,7-Me2-1,10-phenanthroline) was investigated by Born-Oppenheimer quantum-mechanics/molecular mechanics/molecular dynamics (QM/MM/MD) simulations. We focused on W124•+ ← W122 ET, which is the middle step of the photochemical hole-hopping process *ReII(CO)3(dmp•-) ← W124 ← W122 ← CuI, where sequential hopping amounts to nearly 10,000-fold acceleration over single-step tunneling (ACS Cent. Sci. 2019, 5, 192-200). In accordance with experiments, UKS-DFT QM/MM/MD simulations identified forward and reverse steps of W124•+ ↔ W122 ET equilibrium, as well as back ET ReI(CO)3(dmp•-) → W124•+ that restores *ReII(CO)3(dmp•-). Strong electronic coupling between the two indoles (≥40 meV in the crossing region) makes the productive W124•+ ← W122 ET adiabatic. Energies of the two redox states are driven to degeneracy by fluctuations of the electrostatic potential at the two indoles, mainly caused by water solvation, with contributions from the protein dynamics in the W122 vicinity. ET probability depends on the orientation of Re(CO)3(dmp) relative to W124 and its rotation diminishes the hopping yield. Comparison with hole hopping in natural systems reveals structural and dynamics factors that are important for designing efficient hole-hopping processes.