A Soft-Tissue Driven Bone Remodeling Algorithm for Mandibular Residual Ridge Resorption Based on Patient CT Image Data.

The role of the biomechanical stimulation generated from soft tissue has not been well quantified or separated from the self-regulated hard tissue remodeling governed by Wolff's Law. Prosthodontic overdentures, commonly used to restore masticatory functions, can cause localized ischemia and inflammation as they often compress patients' oral mucosa and impede local circulation. This biomechanical stimulus in mucosa is found to accelerate the self-regulated residual ridge resorption (RRR), posing ongoing clinical challenges. Based on the dedicated long-term clinical datasets, we developed an in-silico framework with a combination of techniques, including advanced image post-processing, patient-specific finite element models and unsupervised machine learning Self-Organizing map algorithm, to identify the soft tissue induced residual ridge resorption and quantitatively elucidate the governing relationship between the RRR and hydrostatic pressure in mucosa. The proposed governing equation has not only enabled a predictive simulation for RRR as showcased in this study, providing a biomechanical basis for optimizing prosthodontic treatments, but also extended our understanding of the mechanobiological responses in the soft-hard tissue interfaces and the role in bone remodeling. This article is protected by copyright. All rights reserved.

On-road evaluation and regulatory recommendations for NOx and particle number emissions of China VI heavy-duty diesel trucks: A case study in Shenzhen.

This research analyzed the real-world NOx and particle number (PN) emissions of 21 China VI heavy-duty diesel trucks (HDDTs). On-road emission conformity was first evaluated with portable emission measurement system (PEMS). Only 76.19 %, 71.43 % and 61.90 % of the vehicles passed the NOx test, PN test and both tests, respectively. The impacts of vehicle features including exhaust gas recirculation (EGR) equipment, mileage and tractive tonnage were then assessed. Results demonstrated that EGR helped reducing NOx emission factors (EFs) while increased PN EFs. Larger mileages and tractive tonnages corresponded to higher NOx and PN EFs, respectively. In-depth analyses regarding the influences of operating conditions on emissions were conducted with both numerical comparisons and statistical tests. Results proved that HDDTs generated higher NOx EFs under low speeds or large vehicle specific powers (VSPs), and higher PN EFs under high speeds or small VSPs in general. In addition, unqualified vehicles generated significantly higher NOx EFs than qualified vehicles on freeways or under speed≥40 km/h, while significant higher PN EFs were generated on suburban roads, freeways or under operating modes with positive VSPs by unqualified vehicles. The reliability and accuracy of on-board diagnostic (OBD) NOx data were finally investigated. Results revealed that 43 % of the test vehicles did not report reliable OBD data. Correlation analyses between OBD NOx and PEMS measurements further demonstrated that the consistency of instantaneous concentrations were generally low. However, sliding window averaged concentrations show better correlations, e.g., the Pearson correlation coefficients on 20s-window averaged concentrations exceeded 0.85 for most vehicles. The research results provide valuable insights into emission regulation, e.g., focusing more on medium- to high-speed operations to identify unqualified vehicles, setting higher standards to improve the quality of OBD data, and adopting window averaged OBD NOx concentrations in evaluating vehicle emission performance.

Stereodivergent Synthesis of Alkaloid (±)-223A and (±)-6-epi-223A via Rh-Catalyzed Hydroformylation Double Cyclization.

A stereodivergent approach toward total syntheses of Dendrobatid alkaloids 223A and 6-epi-223A is described. The approach features a concise construction of an indolizidine skeleton by Rh-catalyzed domino hydroformylation double cyclization and sequential stereocontrolled transformations such as reductive alkylation or anti-selective α-alkylation of the 5-oxoindolizidine. These stereoselective reactions afford the desired stereochemistry in the targets.

Consideration of vendor-related differences in hepatic metabolic stability data to optimize early ADME screening in drug discovery.

Hepatic metabolic stability is a crucial determinant of oral bioavailability and plasma concentrations of a compound, and its measurement is important in early drug discovery. Preliminary metabolic stability estimations are commonly performed in liver microsomal fractions. At the National Center for Advancing Translational Sciences, a single-point assay in rat liver microsomes (RLM) is employed for initial stability assessment (Tier I) and a multi-point detailed stability assay is employed as a Tier II assay for promising compounds. Although the in vitro and in vivo metabolic stability of compounds typically exhibit good correlation, conflicting results may arise in certain cases. While investigating one such instance, we serendipitously found vendor-related RLM differences in metabolic stability and metabolite formation, which had implications for in vitro and in vivo correlations. In this study, we highlight the importance of considering vendor differences in hepatic metabolic stability data and discuss strategies to avoid these pitfalls.

Hierarchical neural architecture search with adaptive global-local feature learning for Magnetic Resonance Image reconstruction.

Neural architecture search (NAS) has been introduced into the design of deep neural network architectures for Magnetic Resonance Imaging (MRI) reconstruction since NAS-based methods can acquire the complex network architecture automatically without professional designing experience and improve the model's generalization ability. However, current NAS-based MRI reconstruction methods suffer from a lack of efficient operators in the search space, which leads to challenges in effectively recovering high-frequency details. This limitation is primarily due to the prevalent use of convolution operators in the current search space, which struggle to capture both global and local features of MR images simultaneously, resulting in insufficient information utilization. To address this issue, a generative adversarial network (GAN) based model is proposed to reconstruct the MR image from under-sampled K-space data. Firstly, parameterized global and local feature learning modules at multiple scales are added into the search space to improve the capability of recovering high-frequency details. Secondly, to mitigate the increased search time caused by the augmented search space, a hierarchical NAS is designed to learn the global-local feature learning modules that enable the reconstruction network to learn global and local information of MR images at different scales adaptively. Thirdly, to reduce the number of network parameters and computational complexity, the standard operations in global-local feature learning modules are replaced with lightweight operations. Finally, experiments on several publicly available brain MRI image datasets evaluate the performance of the proposed method. Compared to the state-of-the-art MRI reconstruction methods, the proposed method yields better reconstruction results in terms of peak signal-to-noise ratio and structural similarity at a lower computational cost. Additionally, our reconstruction results are validated through a brain tumor classification task, affirming the practicability of the proposed method. Our code is available at https://github.com/wwHwo/HNASMRI.

Molecular characterization and expression analysis of nine toll like receptor (TLR) genes in Scortum barcoo under Streptococcus agalactiae infection.

Toll like receptors (TLRs) are important pattern recognition receptors participating in innate immune system. Up to now, no TLR has been identified in Jade perch (Scortum barcoo). In this study, we successfully identified 9 members of TLRs from the Jade perch. Amino acid sequence alignment analysis showed that the whole sequences of these TLRs were highly conserved among different fish species, especially in LRR, TM and TIR domains. Phylogenetic analysis revealed that each SbTLR was successfully grouped into corresponding gene family of teleosts. Expression analysis showed that most SbTLRs mainly expressed in liver, spleen, muscle and skin, while expressed less in brain and stomach. After Streptococcus agalactiae infection, expression of SbTLR2, SbTLR5S and SbTLR22 were significantly upregulated, while SbTLR3, SbTLR5M, SbTLR9, SbTLR13, and SbTLR14 were significantly downregulated. In all, this research first reported molecular characterization and expression profiles of 9 TLRs in Jade perch. These data will make a contribution for better understanding the antibacterial mechanism of TLRs in teleosts.

Host heparan sulfate promotes ACE2 super-cluster assembly and enhances SARS-CoV-2-associated syncytium formation.

SARS-CoV-2 infection causes spike-dependent fusion of infected cells with ACE2 positive neighboring cells, generating multi-nuclear syncytia that are often associated with severe COVID. To better elucidate the mechanism of spike-induced syncytium formation, we combine chemical genetics with 4D confocal imaging to establish the cell surface heparan sulfate (HS) as a critical stimulator for spike-induced cell-cell fusion. We show that HS binds spike and promotes spike-induced ACE2 clustering, forming synapse-like cell-cell contacts that facilitate fusion pore formation between ACE2-expresing and spike-transfected human cells. Chemical or genetic inhibition of HS mitigates ACE2 clustering, and thus, syncytium formation, whereas in a cell-free system comprising purified HS and lipid-anchored ACE2, HS stimulates ACE2 clustering directly in the presence of spike. Furthermore, HS-stimulated syncytium formation and receptor clustering require a conserved ACE2 linker distal from the spike-binding site. Importantly, the cell fusion-boosting function of HS can be targeted by an investigational HS-binding drug, which reduces syncytium formation in vitro and viral infection in mice. Thus, HS, as a host factor exploited by SARS-CoV-2 to facilitate receptor clustering and a stimulator of infection-associated syncytium formation, may be a promising therapeutic target for severe COVID.

CDN1163, a SERCA activator, causes intracellular Ca2+ leak, mitochondrial hyperpolarization and cell cycle arrest in mouse neuronal N2A cells.

OBJECTIVE: Activity or expression of sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA) is diminished in some disease states such as cardiac failure and diabetes mellitus. A newly developed activator of SERCA, CDN1163, reportedly rescued or alleviated pathological conditions attributed to dysfunctional SERCA. We examined whether CDN1163 could relieve mouse neuronal N2A cell growth inhibition caused by cyclopiazonic acid (CPA, SERCA inhibitor). We also examined how CDN1163 affected cytosolic Ca2+, mitochondrial Ca2+ and mitochondrial membrane potential. METHODS: Cell viability was measured by MTT assay and trypan blue exclusion test. Cytosolic Ca2+, mitochondrial Ca2+ and mitochondrial membrane potential were measured using fura 2, Rhod-2 and JC-1, respectively, as fluorescent probes. RESULTS: CDN1163 (10 µM) itself suppressed cell proliferation, and did not alleviate CPA's inhibitory effect (and vice versa). Cell cycle was arrested at the G1 phase after CDN1163 treatment. CDN1163 treatment caused a slow yet persistent cytosolic [Ca2+] elevation partly due to Ca2+ release from an internal store other than the CPA-sensitive endoplasmic reticulum (ER). Treatment with CDN1163 for 3 h raised mitochondrial Ca2+ level and such increase was suppressed by MCU-i4 (an inhibitor of mitochondria Ca2+ uniporter, MCU), suggesting Ca2+ entered the mitochondrial matrix through MCU. Treatment of cells with CDN1163 up to 2 days resulted in mitochondrial hyperpolarization. CONCLUSION: CDN1163 caused internal Ca2+ leak, cytosolic Ca2+ overload, mitochondrial Ca2+ elevation and hyperpolarization, cell cycle arrest and cell growth inhibition.

Identification of Potent and Selective Acetylcholinesterase/Butyrylcholinesterase Inhibitors by Virtual Screening.

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) play important roles in human neurodegenerative disorders such as Alzheimer's disease. In this study, machine learning methods were applied to develop quantitative structure-activity relationship models for the prediction of novel AChE and BChE inhibitors based on data from quantitative high-throughput screening assays. The models were used to virtually screen an in-house collection of ∼360K compounds. The optimal models achieved good performance with area under the receiver operating characteristic curve values ranging from 0.83 ± 0.03 to 0.87 ± 0.01 for the prediction of AChE/BChE inhibition activity and selectivity. Experimental validation showed that the best-performing models increased the assay hit rate by several folds. We identified 88 novel AChE and 126 novel BChE inhibitors, 25% (AChE) and 53% (BChE) of which showed potent inhibitory effects (IC50 < 5 µM). In addition, structure-activity relationship analysis of the BChE inhibitors revealed scaffolds for chemistry design and optimization. In conclusion, machine learning models were shown to efficiently identify potent and selective inhibitors against AChE and BChE and novel structural series for further design and development of potential therapeutics against neurodegenerative disorders.

Heparan sulfate promotes ACE2 super-cluster assembly to enhance SARS-CoV-2-associated syncytium formation.

The mechanism of syncytium formation, caused by spike-induced cell-cell fusion in severe COVID-19, is largely unclear. Here we combine chemical genetics with 4D confocal imaging to establish the cell surface heparan sulfate (HS) as a critical host factor exploited by SARS-CoV-2 to enhance spike’s fusogenic activity. HS binds spike to facilitate ACE2 clustering, generating synapse-like cell-cell contacts to promote fusion pore formation. ACE2 clustering, and thus, syncytium formation is significantly mitigated by chemical or genetic elimination of cell surface HS, while in a cell-free system consisting of purified HS, spike, and lipid-anchored ACE2, HS directly induces ACE2 clustering. Importantly, the interaction of HS with spike allosterically enables a conserved ACE2 linker in receptor clustering, which concentrates spike at the fusion site to overcome fusion-associated activity loss. This fusion-boosting mechanism can be effectively targeted by an investigational HS-binding drug, which reduces syncytium formation in vitro and viral infection in mice.

Use of physiological based pharmacokinetic modeling for cross-species prediction of pharmacokinetic and tissue distribution profiles of a novel niclosamide prodrug.

Introduction: Niclosamide (Nc) is an FDA-approved anthelmintic drug that was recently identified in a drug repurposing screening to possess antiviral activity against SARS-CoV-2. However, due to the low solubility and permeability of Nc, its in vivo efficacy was limited by its poor oral absorption. Method: The current study evaluated a novel prodrug of Nc (PDN; NCATS-SM4705) in improving in vivo exposure of Nc and predicted pharmacokinetic profiles of PDN and Nc across different species. ADME properties of the prodrug were determined in humans, hamsters, and mice, while the pharmacokinetics (PK) of PDN were obtained in mice and hamsters. Concentrations of PDN and Nc in plasma and tissue homogenates were measured by UPLC-MS/MS. A physiologically based pharmacokinetic (PBPK) model was developed based on physicochemical properties, pharmacokinetic and tissue distribution data in mice, validated by the PK profiles in hamsters and applied to predict pharmacokinetic profiles in humans. Results: Following intravenous and oral administration of PDN in mice, the total plasma clearance (CLp) and volume of distribution at steady-state (Vdss) were 0.061-0.063 L/h and 0.28-0.31 L, respectively. PDN was converted to Nc in both liver and blood, improving the systemic exposure of Nc in mice and hamsters after oral administration. The PBPK model developed for PDN and in vivo formed Nc could adequately simulate plasma and tissue concentration-time profiles in mice and plasma profiles in hamsters. The predicted human CLp/F and Vdss/F after an oral dose were 2.1 L/h/kg and 15 L/kg for the prodrug respectively. The predicted Nc concentrations in human plasma and lung suggest that a TID dose of 300 mg PDN would provide Nc lung concentrations at 8- to 60-fold higher than in vitro IC50 against SARS-CoV-2 reported in cell assays. Conclusion: In conclusion, the novel prodrug PDN can be efficiently converted to Nc in vivo and improves the systemic exposure of Nc in mice after oral administration. The developed PBPK model adequately depicts the mouse and hamster pharmacokinetic and tissue distribution profiles and highlights its potential application in the prediction of human pharmacokinetic profiles.

Characterization and expression analysis of the interferon regulatory factor (IRF) gene family in zig-zag eel (Mastacembelus armatus) against Aeromonas veronii infection.

Interferon regulatory factors (IRFs) play an important role in innate and adaptive immune system. However, in teleosts, the data on IRFs is still scarce. Here, for the first time, we identified 11 members of IRFs from the zig-zag eel Mastacembelus armatus (MarIRF1-10). The deduced protein sequences are highly conserved among different fish species especially in DBD and IAD domain. Phylogenetic analysis indicated that MarIRFs preferentially grouped with fish species in Synbranchiformes or Perciformes. Expression analysis showed that MarIRFs were expressed in all nine tissues including spleen, gill, muscle and intestine. After infected by Aeromonas veronii, expression of MarIRF2, MaIRF4b and MaIRF5 were significantly upregulated in spleen, MarIRF1, MarIRF2 were significantly upregulated in kidney, but in liver, nearly all MarIRFs were downregulated. Taken together, this study first reported molecular characterization and expression patterns of 11 IRFs in the zig-zag eel. All these results will contribute a lot to better understanding the antibacterial mechanism of IRFs in teleosts.

Preclinical Pharmacokinetics and In Vitro Properties of GS-441524, a Potential Oral Drug Candidate for COVID-19 Treatment.

Preclinical pharmacokinetics (PK) and In Vitro ADME properties of GS-441524, a potential oral agent for the treatment of Covid-19, were studied. GS-441524 was stable in vitro in liver microsomes, cytosols, and hepatocytes of mice, rats, monkeys, dogs, and humans. The plasma free fractions of GS-441524 were 62-78% across all studied species. The in vitro transporter study results showed that GS-441524 was a substrate of MDR1, BCRP, CNT3, ENT1, and ENT2; but not a substrate of CNT1, CNT2, and ENT4. GS-441524 had a low to moderate plasma clearance (CLp), ranging from 4.1 mL/min/kg in dogs to 26 mL/min/kg in mice; the steady state volume distribution (Vdss) ranged from 0.9 L/kg in dogs to 2.4 L/kg in mice after IV administration. Urinary excretion appeared to be the major elimination process for GS-441524. Following oral administration, the oral bioavailability was 8.3% in monkeys, 33% in rats, 39% in mice, and 85% in dogs. The PK and ADME properties of GS-441524 support its further development as an oral drug candidate.

Anti-biofouling Ti3C2TX MXene-holey graphene modified electrode for dopamine sensing in complex biological fluids.

With the development of new methods for the medical diagnosis, electrochemical sensors have attracted increasing attention. However, biofouling on the surface of the sensor significantly decreases sensor performance, thereby limiting the application of electrochemical sensors in complex biological fluids. Given the urgent need for anti-biofouling electrodes, a sensor based on a glass carbon electrode (GCE) modified with Ti3C2TX MXene and electrochemically reduced holey graphene (ERHG) was fabricated and demonstrated to have excellent electrochemical performance and anti-biofouling properties. ERHG provides abundant surface-active sites and imparts stability by hindering the agglomeration and oxidation of MXene. Furthermore, the excellent conductivity and hydrophilicity of MXene result in a high electron transfer rate and strong hydrophilicity. The MXene-ERHG/GCE sensor can detect dopamine with a wide linear range (0.2-125 µM) and a low detection limit of 0.044 µM in phosphate-buffer saline solution. Importantly, the hydrophilicity of MXene-ERHG reduces non-specific protein adsorption on the electrode surface, providing resistance to biofouling. After immersion in bovine serum albumin for 30 min, MXene-ERHG/GCE retained 85.90% of its initial peak current value, much higher than that of ERHG/GCE (17.75%). The MXene-ERHG/GCE sensor also showed good sensitivity for dopamine detection in serum and artificial cerebrospinal fluid (aCSF) containing bovine serum albumin. Moreover, MXene-ERHG/GCE exhibited excellent reproducibility and long-term stability in aCSF. The results demonstrate that MXene-ERHG/GCE has excellent anti-biofouling performance, and shows potential as an electrode material for application in biosensing.

High-Throughput Platform for Novel Reaction Discovery.

Detecting the formation of new chemical bonds in high-throughput synthesis is limited by the efficiency and scalability of reaction product detection, as conventional methods for isolating product from reaction mixtures are time consuming and labor intensive. Here, we report a miniaturizable purification method that enables the rapid, high-throughput isolation of quaternary ammonium-tagged products from reaction mixtures with excellent purity using inexpensive equipment that easily can be set up in a typical organic chemistry laboratory. This novel purification technique enabled us to establish a high-throughput reaction discovery platform. We validated this platform in a screen of 1536 reactions, and one previously unreported transformation was identified.

Comparison of the Efficacies of Direct-Acting Antiviral Treatment for HCV Infection in People Who Inject Drugs and Non-Drug Users.

Background and Objectives: Hepatitis C virus (HCV) is a major cause of liver disease worldwide. People who inject drugs (PWIDs) constitute the majority of patients with HCV infection in the United States and Central Asia. There are several obstacles to treating HCV infection in PWIDs because PWIDs are often accompanied by concurrent infection, low compliance, substance abuse, and risky behavior. The aim of the study is to compare the efficacies of direct-acting antiviral (DAA) therapy for HCV infection in PWIDs and those without opioid injection. Materials and Methods: In this retrospective cohort study, we included 53 PWIDs with HCV infections treated on site in a methadone program and 106 age- and sex-matched patients with HCV infections who had no history of opioid injection (ratio of 1:2). All eligible subjects received anti-HCV treatment by DAA agents in our hospital from March 2018 to December 2020. The charts of these patients were carefully reviewed for demographic data, types of DAA agents, and treatment outcomes. The primary outcome measure was sustained virological response (SVR). Results: PWIDs and non-drug users had different HCV genotype profiles (p = 0.013). The former had higher proportions of genotype 3 (18.9% vs. 7.5%) and genotype 6 (24.5% vs. 14.2%) than the latter. The two patient groups had comparable rates of complete drug refilling (100.0% vs. 91.1%) and frequency of loss to follow-up (3.8% vs. 0.9%). However, PWIDs had a lower SVR rate of DAA treatment than non-drug users (92.2% vs. 99.0%; p = 0.04). Further analysis showed that both human immunodeficiency virus (HIV) coinfection and history of PWID were risk factors associated with treatment failure. The subjects with coinfection with HIV had lower SVR rates than those without HIV infection (50.0% vs. 96.5%; p = 0.021). Conclusions: PWIDs with HCV infections have higher proportions of HCV genotype 3 and genotype 6 than non-drug users with infections. DAA therapy can achieve a high cure rate (>90%) for HCV infection in PWID, but its efficacy in PWID is lower than that in non-drug users.

iPS-derived neural stem cells for disease modeling and evaluation of therapeutics for mucopolysaccharidosis type II.

Mucopolysaccharidosis type II (MPS II), also known as Hunter syndrome, is a rare, lysosomal disorder caused by mutations in a gene encoding iduronate-2-sulfatase (IDS). IDS deficiency results in an accumulation of glycosaminoglycans (GAGs) and secondary accumulations of other lipids in lysosomes. Symptoms of MPS II include a variety of soft and hard tissue problems, developmental delay, and deterioration of multiple organs. Enzyme replacement therapy is an approved treatment for MPS II, but fails to improve neuronal symptoms. Cell-based neuronal models of MPS II disease are needed for compound screening and drug development for the treatment of the neuronal symptoms in MPS II. In this study, three induced pluripotent stem cell (iPSC) lines were generated from three MPS II patient-derived dermal fibroblast cell lines that were differentiated into neural stem cells and neurons. The disease phenotypes were measured using immunofluorescence staining and Nile red dye staining. In addition, the therapeutic effects of recombinant human IDS enzyme, delta-tocopherol (DT), and hydroxypropyl-beta-cyclodextrin (HPBCD) were determined in the MPS II disease cells. Finally, the neural stem cells from two of the MPS II iPSC lines exhibited typical disease features including a deficiency of IDS activity, abnormal glycosaminoglycan storage, and secondary lipid accumulation. Enzyme replacement therapy partially rescued the disease phenotypes in these cells. DT showed a significant effect in reducing the secondary accumulation of lipids in the MPS II neural stem cells. In contrast, HPBCD displayed limited or no effect in these cells. Our data indicate that these MPS II cells can be used as a cell-based disease model to study disease pathogenesis, evaluate drug efficacy, and screen compounds for drug development.

De Novo Assembly, Characterization and Comparative Transcriptome Analysis of the Mature Gonads in Spinibarbus hollandi.

Spinibarbus hollandi is an important commercial aquaculture species in southeastern China, but with long maturity period and low egg laying amount. However, there has been little study of its gonad development and reproductive regulation, which limits aquaculture production. Here, for the first time, gonadal transcriptomes of male and female S. hollandi were analyzed. A total of 167,152 unigenes were assembled, with only 48,275 annotated successfully. After comparison, a total of 21,903 differentially expressed genes were identified between male and female gonads, of which 16,395 were upregulated and 5508 were downregulated in the testis. In addition, a large number of differentially expressed genes participating in reproduction, gonad formation and differentiation, and gametogenesis were screened out and the differential expression profiles of partial genes were further validated using quantitative real-time PCR. These results will provide basic information for further research on gonad differentiation and development in S. hollandi.