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In recent years, an increasing number of emerging and remerging virus outbreaks have occurred and the rapid development of vaccines against these viruses has been crucial. Controlling the replication of premature termination codon (PTC)-containing viruses is a promising approach to generate live but replication-defective viruses that can be used for potent vaccines. Here, we used anticodon-engineered transfer RNAs (ACE-tRNAs) as powerful precision switches to control the replication of PTC-containing viruses. We showed that ACE-tRNAs display higher potency of reading through PTCs than genetic code expansion (GCE) technology. Interestingly, ACE-tRNA has a site preference that may influence its read-through efficacy. We further attempted to use ACE-tRNAs as a novel viral vaccine platform. Using a human immunodeficiency virus type 1 (HIV-1) pseudotyped virus as an RNA virus model, we found that ACE-tRNAs display high potency for read-through viral PTCs and precisely control their production. Pseudorabies virus (PRV), a herpesvirus, was used as a DNA virus model. We found that ACE-tRNAs display high potency for reading through viral PTCs and precisely controlling PTC-containing virus replication. In addition, PTC-engineered PRV completely attenuated and lost virulence in mice in vivo, and immunization with PRV containing a PTC elicited a robust immune response and provided complete protection against wild-type PRV challenge. Overall, replication-controllable PTC-containing viruses based on ACE-tRNAs provide a new strategy to rapidly attenuate virus infection and prime robust immune responses. This technology can be used as a platform for rapidly developing viral vaccines in the future.

Modifying the crystal structure and corresponding functional properties of complex oxides by regulating their oxygen content has promising applications in energy conversion and chemical looping, where controlling oxygen migration plays an important role. Therefore, finding an efficacious and feasible method to facilitate oxygen migration has become a critical requirement for practical applications. Here, we report a compressive-strain-facilitated oxygen migration with reversible topotactic phase transformation (RTPT) in La

Alzheimer's disease (AD) is the most common type of dementia characterized by abnormal accumulation of amyloid-β (Aβ) plaques, neuroinflammation, and neuronal loss. Dimethyl itaconate (DI), a membrane-permeable derivative of itaconate, has been recently reported to limit inflammation. However, the effect of DI in the APPswe/PS1ΔE9 (APP/PS1) transgenic mouse model of AD remains unclear. We treated APP/PS1 mice with DI or saline. Our results showed that DI ameliorated the cognitive deficits of APP/PS1 mice. Further, DI significantly decreased brain Aβ deposition and Aβ levels, inhibited cell apoptosis, decreased hippocampal and cortical neuronal damage. We also found that DI promoted the expression of the Nrf2/HO-1 signaling pathway, while inhibited cognitive impairment, cell apoptosis, and the proinflammatory cytokine levels in the brains of APP/PS1 mice. Our results indicated that DI attenuated memory impairment and neuroinflammation via the Nrf2 signaling pathway in APP/PS1 mice, suggesting that DI might be recognized as a promising candidate for the treatment of AD.

Revealing the mechanisms of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry and cell-to-cell spread might provide insights for understanding the underlying mechanisms of viral pathogenesis, tropism, and virulence. The signaling pathways involved in SARS-CoV-2 entry and viral spike-mediated cell-to-cell fusion remain elusive. In the current study, we found that macropinocytosis inhibitors significantly suppressed SARS-CoV-2 infection at both the entry and viral spike-mediated cell-to-cell fusion steps. We demonstrated that SARS-CoV-2 entry required the small GTPase Rac1 and its effector kinase p21-activated kinase 1 by dominant-negative and RNAi assays in human embryonic kidney 293T-angiotensin-converting enzyme 2 cells and that the serine protease transmembrane serine protease 2 reversed the decrease in SARS-CoV-2 entry caused by the macropinocytosis inhibitors. Moreover, in the cell-to-cell fusion assay, we confirmed that macropinocytosis inhibitors significantly decreased viral spike-mediated cell-to-cell fusion. Overall, we provided evidence that SARS-CoV-2 utilizes a macropinocytosis pathway to enter target cells and to efficiently promote viral spike-mediated cell-to-cell fusion.

Porcine deltacoronavirus (PDCoV) is a recently discovered coronavirus that poses a potential threat to the global swine industry. Although we know that aminopeptidase N (APN) is important for PDCoV replication, it is unclear whether it is the primary functional receptor, and the mechanism by which it promotes viral replication is not fully understood. Here, we systematically investigated the role of porcine APN (pAPN) during PDCoV infection of non-susceptible cells, including in viral attachment and internalization. Using a viral entry assay, we found that PDCoV can enter non-susceptible cells but then fails to initiate efficient replication. pAPN and PDCoV virions clearly co-localized with the endocytotic markers RAB5, RAB7, and LAMP1, suggesting that pAPN mediates PDCoV entry by an endocytotic pathway. Most importantly, our study shows that regardless of which receptor PDCoV engages, only entry by an endocytotic route ultimately leads to efficient viral replication. This knowledge should contribute to the development of efficient antiviral treatments, which are especially useful in preventing cross-species transmission. IMPORTANCE PDCoV is a pathogen with potential for transmission across diverse species, although the mechanism of such host-switching events (from swine to other species) is poorly understood. Here, we show that PDCoV enters non-susceptible cells, but without efficient replication. We also investigated the key role played by aminopeptidase N in mediating PDCoV entry via an endocytotic pathway. Our results demonstrate that viral entry via endocytosis is a major determinant of efficient PDCoV replication. This knowledge provides a basis for future studies of the cross-species transmissibility of PDCoV and the development of appropriate anti-viral drugs.

Current Internet is evolving with the gradual shift from the traditional host-to-host communication model to the new host-to-content paradigm, which will eventually lead to a network of caches. The novel Named Data Networking (NDN) has been proposed as a future Internet architecture to embrace this paradigmatic shift, where caching becomes an ubiquitous functionality available at each router.A router with the functionality of content caching, running on NDN mechanisms, is termed as an NDN-based content router. Previous researchers focused on software content routers (SCR), which leverage a commercial off-the-shelf computer to execute content caching/accessing and named-based packet forwarding. SCR can only achieve limited throughput, which is far below the speed requirements of modern routers. Facing this situation, in this paper, we propose a hardware-based content router (HCR), aiming at purchasing wire-speed processing. We design a physically concise architecture for decoupling the packet buffers in line cards from the content caches attached to storage cards, enabling separate management and optimization while facilitating a modular structure for smooth capacity upgrade in response to increasing storage utilization. For lowering the operating complexity and reducing the storage management cost, we choose to employ distributed caches working in a cooperated manner by using consistent hashing. We model several candidate storage organizing schemes and carry out theoretical analyses for comparison. Analytical and synthetic workload-driven results show that the consistent hashing scheme achieves high cache performance and low cost simultaneously.

As one of many nonstructural proteins of porcine reproductive and respiratory syndrome virus (PRRSV), nonstructural protein 12 (Nsp12) has received relatively little attention, and its role in virus replication, if any, is essentially unknown. By the application of reverse genetic manipulation of an infectious PRRSV clone, the current study is the first to demonstrate that Nsp12 is a key component of PRRSV replication. In addition, the biochemical properties of Nsp12 were evaluated, revealing that Nsp12 forms dimers when exposed to oxidative conditions. Furthermore, we systemically analyzed the function of Nsp12 in PRRSV RNA synthesis using a strand-specific PCR method. To our surprise, Nsp12 was not found to be involved in minus-strand genomic RNA (-gRNA) synthesis; importantly, our results indicate that Nsp12 is involved in the synthesis of both plus- and minus-strand subgenomic mRNAs (+sgmRNA and -sgmRNA). Finally, we found that the combination of cysteine 35 and cysteine 79 in Nsp12 is required for sgmRNA synthesis. To our knowledge, we are the first to report the biological role of Nsp12 in the PRRSV lifecycle, and we conclude that Nsp12 is involved in the synthesis of both + sgRNA and -sgRNA.

HoBi single crystal and polycrystalline compounds with NaCl-type structure are successfully obtained, and their magnetic and magnetocaloric properties are studied in detail. With temperature increasing, HoBi compound undergoes two magnetic transitions at 3.7 K and 6 K, respectively. The transition temperature at 6 K is recognized as an antiferromagnetic-to-paramagnetic (AFM–PM) transition, which belongs to the first-order magnetic phase transition (FOMT). It is interesting that the HoBi compound with FOMT exhibits good thermal and magnetic reversibility. Furthermore, a large inverse and normal magnetocaloric effect (MCE) is found in HoBi single crystal in the H||[100] direction, and the positive ΔS M peak reaches 13.1 J/kg⋅K under a low field change of 2 T and the negative ΔS M peak arrives at –18 J/kg⋅K under a field change of 5 T. These excellent properties are expected to be applied to some magnetic refrigerators with special designs and functions.

Despite many efforts and diverse approaches, developing an effective herpesvirus vaccine remains a great challenge. Traditional inactivated and live-attenuated vaccines always raise efficacy or safety concerns. This study used Pseudorabies virus (PRV), a swine herpes virus, as a model. We attempted to develop a live but replication-incompetent PRV by genetic code expansion (GCE) technology. Premature termination codon (PTC) harboring PRV was successfully rescued in the presence of orthogonal system MbpylRS/tRNAPyl pair and unnatural amino acids (UAA). However, UAA incorporating efficacy seemed extremely low in our engineered PRV PTC virus. Furthermore, we failed to establish a stable transgenic cell line containing orthogonal translation machinery for PTC virus replication, and we demonstrated that orthogonal tRNAPyl is a key limiting factor. This study is the first to demonstrate that orthogonal translation system-mediated amber codon suppression strategy could precisely control PRV-PTC engineered virus replication. To our knowledge, this is the first reported PTC herpesvirus generated by GCE technology. Our work provides a proof-of-concept for generating UAAs-controlled PRV-PTC virus, which can be used as a safe and effective vaccine.

Approximate counters play an important role in many computer domains like network measurement, parallel computing and machine learning because they can reduce the required memory cost. With the emergence of new application needs in these domains like flow counting and parallel measuring, simple Morris counters fail to solve them. Therefore, a more general Morris counter is required. However, there has been a lack of complete theoretical research on the statistical properties of this new approximate counter so far.This paper conducts a deep analysis on general Morris counters and derives the minimum upper bound of the variance. To our best knowledge, this is the first work to thoroughly analyze the statistical properties of general Morris counters in theory. Besides, application scenarios are analyzed, showing that conclusions obtained by our research are effective in testing the performance of approximate counters and guiding system architecture design according to accuracy needs.

The outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a huge threat to many countries around the world. However, where is it origin and which animals are sensitive to cross-species transmission is unclear. The interaction of virus and cell receptor is a key determinant of host range for the novel coronavirus. Angiotensin-converting enzyme 2 (ACE2) is demonstrated as the primary entry receptor for SARS-CoV-2. In this study, we evaluated the SARS-CoV-2 entry mediated by ACE2 of 11 different species of animals, and discovered that ACE2 of Rhinolophus sinicus (Chinese horseshoe bat), Felis catus (domestic cat), Canis lupus familiaris (dog), Sus scrofa (pig), Capra hircus (goat) and especially Manis javanica (Malayan pangolin) were able to render SARS-CoV-2 entry in non-susceptible cells. This is the first report that ACE2 of Pangolin could mediate SARS-CoV-2 entry which increases the presume that SARS-CoV-2 may have a pangolin origin. However, none of the ACE2 proteins from Rhinolophus ferrumequinum (greater horseshoe bat), Gallus gallus (chicken), Notechis scutatus (mainland tiger snake), Mus musculus (house mouse) rendered SARS-CoV-2 entry. Specifically, a natural isoform of Macaca mulatta (Rhesus monkey) ACE2 with a mutation of Y217N was resistance to infection, which rises the possible impact of this type of ACE2 during monkey studies of SARS-CoV-2. Overall, these results clarify that SARS-CoV-2 could engage receptors of multiple species of animals and it is a perplexed work to track SARS-CoV-2 origin and its intermediate hosts.IMPORTANCEIn this study, we illustrated that SARS-CoV-2 is able to engage receptors of multiple species of animals. This indicated that it may be a perplexed work to track SARS-CoV-2 origin and discover its intermediate hosts. This feature of virus is considered to potentiate its diverse cross-species transmissibility. Of note, here is the first report that ACE2 of Pangolin could mediate SARS-CoV-2 entry which increases the possibility that SARS-CoV-2 may have a pangolin origin. And we also demonstrated that not all species of bat were sensitive to SARS-CoV-2 infection. At last, it is also important to detect the expression ratio of the Y217N ACE2 to the prototype in Rhesus monkeys to be recruited for studies on SARS-CoV-2 infection.

Several groups have used CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) for DNA virus editing. In most cases, one single-guide RNA (sgRNA) is used, which produces inconsistencies in gene editing. In this study, we used a swine herpesvirus, pseudorabies virus, as a model to systematically explore the application of CRISPR/Cas9 in DNA virus editing. In our current report, we demonstrated that cotransfection of 2 sgRNAs and a viral genome resulted in significantly better knockout efficiency than the transfection-infection-based approach. This method could result in 100% knockout of ≤3500 bp of viral nonessential large fragments. Furthermore, knockin efficiency was significantly improved by using 2 sgRNAs and was also correlated with the number of background viruses. We also demonstrated that the background viruses were all 2-sgRNA-mediated knockout mutants. Finally, this study demonstrated that the efficacy of gene knockin is determined by the replicative kinetics of background viruses. We propose that CRISPR/Cas9 coupled with 2 sgRNAs creates a powerful tool for DNA virus editing and offers great potential for future applications.-Tang, Y.-D., Guo, J.-C., Wang, T.-Y., Zhao, K., Liu, J.-T., Gao, J.-C., Tian, Z.-J., An, T.-Q., Cai, X.-H. CRISPR/Cas9-mediated 2-sgRNA cleavage facilitates pseudorabies virus editing.

A fluorescent assay for Hg 2+ was developed based on magnetic separation and the formation of T-Hg 2+ -T base pairs. The aptamers were immobilized on the surfaces of magnetic beads to form aptamers-functionalized magnetic beads (AMB). In the absence of Hg 2+ , the signal transduction probe (STP) can combine with AMB through complementary base pairing. There is almost no STP in the detection solution after magnetic separation, which results in the fluorescence signal quite weak. The presence of Hg 2+ leads to the formation of T-Hg 2+ -T base pairs between aptamers and help DNA. After magnetic separation, Hg 2+ is separated from the system and STP is left in the solution, so the fluorescence signal was significantly enhanced. The fluorescence intensity linearly increased with the increasing of Hg 2+ concentration from 2 to 160 nM with the detection limit of 0.2 nM. This method has been successfully applied to test and quantify Hg 2+ in river water and ribbon fish with satisfactory recoveries, and the results were in full agreement with those from the atomic fluorescence spectroscopy (AFS). As-built method could avoid the direct binding of Hg 2+ with the fluorescent signal probe. Therefore, combining with magnetic separation, the heavy metal-fluorescence quenching effects could be effectively eliminated.

Pseudorabies virus (PRV) is a swine herpesvirus that causes significant morbidity and mortality in swine populations and has caused huge economic losses in the worldwide swine industry. Currently, there is no effective antiviral drug in clinical use for PRV infection; it is also difficult to eliminate PRV from infected swine. In our study, we set out to combat these swine herpesvirus infections by exploiting the CRISPR/Cas9 system. We designed 75 single guide RNAs (sgRNA) by targeting both essential and non-essential genes across the genome of PRV. We applied a firefly luciferase-tagged reporter PRV virus for high-throughput sgRNA screening and found that most of the sgRNAs significantly inhibited PRV replication. More importantly, using a transfection assay, we demonstrated that simultaneous targeting of PRV with multiple sgRNAs completely abolished the production of infectious viruses in cells. These data suggest that CRISPR/Cas9 could be a novel therapeutic agent against PRV in the future.

A series of misch-metal (MM = 28.27 wt % La, 50.46 wt % Ce, 5.22 wt % Pr, 15.66 wt % Nd)-iron-boron isotropic ribbons with atomic formula (MM)12+xFe82-x-yB6+y (x = 0, 1, 2, 3, 4, y = 0, 0.5, 1, 1.5, 2) are prepared by melt spinning technique. A large energy product (BH)max of 12 MGOe is obtained with the composition of MM13Fe81B6 at optimized processing. The ribbons with both coercivity larger than 10 kOe and (BH)max larger than 10 MGOe are achieved in a wide composition range. All the samples exhibit the tetragonal crystal structure. The magnetization and Henkel plot (δM) measurements indicate that the ribbons have a relatively homogeneous microstructure and strong exchange-coupling interactions. The average grain size of the ribbons is around 30 nm determined via Scherrer's formula. Meanwhile, the transmission electron microscope (TEM) image also verifies that the ribbons have a homogeneous nanoscale microstructure. In addition, the spin reorientation temperature Tsr is investigated by ac susceptibility χac measurement.

In Vehicular Ad Hoc NETworks (VANET), dynamic topology changes of network and inconstant bandwidth make it hard to maintain an end-to-end path to complete long-time stable data transmission. Facing this challenge, researchers have proposed the hybrid routing approach, which tries to combine both the advantages of recalculating route when topology changes and looking up routing table as long as the network topology is relatively stable. However, the existing hybrid routing algorithms can easily cause the blind path problem, meaning a route entry is kept in the routing table without expiration according to the timeout mechanism but it is actually invalid, because the next hop is already unavailable. To address this issue, we propose a Reinforcement learning based Hybrid Routing algorithm (RHR) that can online track the available paths with their status and use packet-carry-on information as real-time feedback to guide routing. RHR keeps the forwarding path always the freshest and thus improves the system performance. Simulation results show that RHR achieves better performance in packet delivery ratio (PDR), roundtrip time (RTT) and overhead than other peers under different scenarios of network scale, request frequency and vehicle velocity.

Dermal fibroblasts (dFBs) resist infection by locally differentiating into adipocytes and producing cathelicidin antimicrobial peptide in response to Staphylococcus aureus (S.aureus). Here, we show that neonatal skin was enriched with adipogenic dFBs and immature dermal fat that highly expressed cathelicidin. The pool of adipogenic and antimicrobial dFBs declined after birth, leading to an age-dependent loss of dermal fat and a decrease in adipogenesis and cathelidicin production in response to infection. Transforming growth factor beta (TGF-β), which acted on uncommitted embryonic and adult dFBs and inhibited their adipogenic and antimicrobial function, was identified as a key upstream regulator of this process. Furthermore, inhibition of the TGF-β receptor restored the adipogenic and antimicrobial function of dFBs in culture and increased resistance of adult mice to S.aureus infection. These results provide insight into changes that occur in the skin innate immune system between the perinatal and adult periods of life.

Despite a ban on the production and use of organochlorine pesticides (OCPs) after 1983, serious OCP pollution still exists in the soil in certain areas of China because OCPs degrade very slowly. Based on a systematic review, we identified 136 relevant papers focusing on soil contamination from hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT) in China (published from 2001 to 2019). We compiled scientific data, extracted and analyzed relevant information, and summarized the pollution characteristics of HCH and DDT in Chinese soils found in two land use types: agricultural land and land for construction. Related studies on HCH and DDT in Chinese soils focus on the Beijing–Tianjin–Hebei region and the Yangtze and Pearl River Deltas, where agricultural soils are predominant. The average concentrations of both HCH and DDT in agricultural soils were generally lower than the risk screening value (100 μg/kg) in most provinces in China, except for DDT concentrations in the Inner Mongolia autonomous region. However, in certain central and eastern regions, mean or maximum recorded DDT concentrations approaching or exceeding 100 μg/kg were recorded. Regarding land for construction, soils with excessive concentrations of HCH and DDT were primarily observed at sites of operational or defunct pesticide factories. According to isomer and metabolite compositions, HCH and DDT at most sites originated from historical residues, but others may have been new inputs after 1983. Since 2015, the concentrations of HCH and DDT in agricultural soils in China have been decreasing, and those in the soils of land for construction (except for sites of operational or defunct pesticide factories) have not exceeded the standard after 2005. This indicates that the measures to prohibit the production and use of OCPs in China have been effective. However, the management of operational or defunct pesticide factories polluted by OCPs requires further improvement.

The porcine reproductive and respiratory syndrome virus (PRRSV) causes a persistent threat to the swine industry, especially when highly pathogenic PRRSV (HP-PRRSV) emerges. Previous studies have indicated that PRRSV RNA synthesis was correlated with HP-PRRSV virulence. PRRSV RNA synthesis includes genomic RNA and sub-genomic mRNA, and these processes require minus-strand RNA as a template. However, the mechanisms involved in PRRSV minus-strand RNA synthesis are not fully understood. A mini-genome system can be used to assess viral replication mechanisms and to evaluate the effects of potential antiviral drugs on viral replicase activities. In this study, we developed a mini-genome system that uses firefly luciferase as a reporter. Based on this system, we found that PRRSV RNA-dependent RNA polymerase nsp9 alone failed to activate virus minus-strand RNA synthesis. We also demonstrated that combinations of open reading frames 1a (ORF1a) and ORF1b are necessary for viral minus-strand RNA synthesis.

Pseudorabies virus (PRV), the causative agent of Aujeszky׳s disease, has gained increased attention in China in recent years as a result of the outbreak of emergent pseudorabies. Several genomic and partial sequences are available for Chinese emergent and European–American strains of PRV, but limited sequence data exist for the earlier Chinese strains. In this study, we determined the complete genomic sequence of one earlier Chinese strain SC and one emergent strain HLJ8. Compared with other known sequences, we demonstrated that PRV strains from distinct geographical regions displayed divergent evolution. Additionally, we report for the first time, a recombination event between PRV strains, and show that strain SC is a recombinant of an endemic Chinese strain and a Bartha-vaccine-like strain. These results contribute to our understanding of PRV evolution.

The transcription factor NF-&kappa, B plays a critical role in diverse biological processes. The NF-&kappa, B pathway can be activated by incoming pathogens and then stimulates both innate and adaptive immunity. However, many viruses have evolved corresponding strategies to balance NF-&kappa, B activation to benefit their replication. Pseudorabies virus (PRV) is an economically important pathogen that belongs to the alphaherpesvirus group. There is little information about PRV infection and NF-&kappa, B regulation. This study demonstrates for the first time that the UL24 protein could abrogate tumor necrosis factor alpha (TNF-&alpha, )-mediated NF-&kappa, B activation. An overexpression assay indicated that UL24 inhibits this pathway at or downstream of P65. Furthermore, co-immunoprecipitation analysis demonstrated that UL24 selectively interacts with P65. We demonstrated that UL24 could significantly degrade P65 by the proteasome pathway. For the first time, PRV UL24 was shown to play an important role in NF-&kappa, B evasion during PRV infection. This study expands our understanding that PRV can utilize its encoded protein UL24 to evade NF-&kappa, B signaling.

The effect of procyanidin A2 (PCA2) and its major colonic metabolite 3-(4-hydroxyphenyl)propionic acid (HPPA) on the suppression of macrophage foam cell formation, and underlying mechanism, were investigated for the first time. The results showed that 12.5 μg mL−1 PCA2 and HPPA significantly reduced cellular lipid accumulation and inhibited foam cell formation. HPPA promoted macrophage cholesterol efflux by up-regulating mRNA expressions of ABCA1 and SR-B1, while PCA2 significantly increased SR-B1 and LXR-α mRNA expression levels. Moreover, PCA2 and HPPA significantly lowered the elevated levels of CD36 mRNA expression in ox-LDL-treated macrophage cells. Besides these, the ox-LDL-induced cellular oxidative stress and inflammation was also restricted by PCA2 and HPPA treatment via nuclear factor kappa-B pathways. In conclusion, PCA2 and its major microbial metabolite, HPPA, inhibited the conversion of macrophage into foam cells via regulating cellular lipid metabolism and suppressing cellular oxidative stress and inflammation.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a major economically significant pathogen that has adversely affected China's swine industry. Currently, a novel type 2 PRRSV, called the NADC30-like strain, is epidemic in numerous provinces of China, and commercial vaccines provide limited protection for infected animals. The extensive recombination phenomenon among NADC30-like PRRSVs is identified as a unique molecular characteristic of the virus. However, our understanding of how recombination influences NADC30-like PRRSVs is largely inadequate. In this study, we analysed the genetic characteristics of a recombinant NADC30-like PRRSV (SC-d) and examined its pathogenicity compared with a non-recombinant NADC30-like PRRSV (SD-A19) and a highly pathogenic PRRSV (HuN4). SC-d has three discontinuous deletions in nsp2, consistent with NADC30 isolated from the United States in 2008. Furthermore, we identified four recombination breakpoints in the SC-d genome, which separated the SC-d genome into four regions (regions A, B, C and D). Regions A and C are closely related to the JXA1-like strain, one of the earliest Chinese HP-PRRSV strains, and regions B and D are closely related to the NADC30 strain. Moreover, SC-d inoculated piglets exhibited a persistent fever, moderate weight loss, mild thymus atrophy and obvious microscopic lung lesions. In summary, the recombinant NADC30-like PRRSV SC-d strain displayed a higher pathogenicity than the non-recombinant NADC30-like PRRSV SD-A19 strain; however, the pathogenicity of the NADC30-like PRRSV SC-d was lower compared with the HP-PRRSV HuN4 strain in piglets. Our findings demonstrate that recombination is responsible for the enormous genetic diversity and pathogenicity variance of the NADC30-like PRRSV in China. This study provides a theoretical basis for developing a more reasonable PRRSV control and prevention strategy.

Elesclomol is a novel anticancer agent that has been evaluated in a number of late stage clinical trials. A new and convenient synthesis of elesclomol and its copper complex is described. X-ray crystallographic characterization and the electrochemical properties of the elesclomol copper(II) complex are discussed. The copper(II) cation is coordinated in a highly distorted square-planar geometry to each of the sulphur and amide nitrogen atoms of elesclomol. Electrochemical measurements demonstrate that the complex undergoes a reversible one-electron reduction at biologically accessible potentials. In contrast the free elesclomol is found electrochemically inactive. This evidence is in strong support of the mechanism of action we proposed for the anticancer activity of elesclomol.

Bacterial artificial chromosomes (BACs) are powerful tools for the manipulation of the large genomes of DNA viruses, such as herpesviruses. However, the methods currently used to construct the recombinant viruses, an important intermediate link in the generation of BACs, involve the laborious process of multiple plaque purifications. Moreover, some fastidious viruses may be lost or damaged during these processes, making it impossible to generate BACs from these large-genome DNA viruses. Here, we introduce the CRISPR/Cas9 as a site-specific gene knock-in instrument that promotes the homologous recombination of a linearized transfer vector and the Pseudorabies virus genome through double incisions. The efficiency of recombination is as high as 86%. To our knowledge, this is the highest efficiency ever reported for Pseudorabies virus recombination. We also demonstrate that the positions and distances of the CRISPR/Cas9 single guide RNAs from the homology arms correlate with the efficiency of homologous recombination. Our work show a simple and fast cloning method of BACs with large genome inserted by greatly enhancing the HR efficiencies through CRISPR/Cas9-mediated homology-directed repair mechanism, and this method could be of helpful for manipulating large DNA viruses, and will provide a successful model for insertion of large DNA fragments into other viruses.

The aim of the present study was to investigate the gene expression of biomarkers associated with the sensitivity to fluoropyrimidine and taxanes in recurrent/advanced breast cancer patients treated with first-line capecitabine chemotherapy. We evaluated the clinicopathological/prognostic significance of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP), class III β-tubulin (βIII-tubulin), and stathmin-1 or oncoprotein-18 (STMN1). Formalin-fixed, paraffin-embedded tumor specimens from 42 patients were used for analysis of TS, DPD, TP, βIII-tubulin, and STMN1 expression with a real-time reverse transcription-PCR technique. Patients were classified into the high-expression and low-expression groups according to the median value of the expression level of each biomarker. There was a significantly longer time to progression (TTP) in the high-TP group (P=0.018). The multivariate analysis revealed that the TP expression (hazard ratio for the low-TP group vs. the high-TP group, 2.873; 95% confidence interval, 1.143-7.223; P=0.025) is independent of prognostic factors for TTP. In the subgroup of patients treated with capecitabine plus taxanes as first-line chemotherapy, TTP was significantly longer in the low-βIII-tubulin group (P=0.047). The gene expression of TS, DPD, and STMN1 failed to have any significant impact on the outcome. These results provide further evidence that the TP expression may be a prognostic factor in breast cancer patients treated with capecitabine-based first-line chemotherapy, and βIII-tubulin can be used to predict the outcome of capecitabine in combination with taxanes as first-line chemotherapy. Therefore, these potential biomarkers should be further evaluated.

Nonviral vectors present considerable advantages over viral counterparts in gene transfer. However, the poor expression efficiency of the transfected genes poses a challenge for their use in gene therapy, primarily due to the inability of these vectors to overcome various barriers, including the biological barriers. Here, we report that ZNF511-PRAP1 may be involved in the recognition and inactivation of transfected plasmids. ZNF511-PRAP1 is induced by transfection of plasmid DNA and suppresses the transcription of transfected plasmids. It binds directly to the p21 promoter in transfected plasmids but not the endogenous counterpart. Similarly, ZNF511-PRAP1 suppresses the expression of the green fluorescent protein reporter gene on transiently transfected plasmids but not an integrated red fluorescence reporter gene with the same cytomegalovirus (CMV) promoter. Therefore, ZNF511-PRAP1 is able to differentiate between exogenous/nonintegrated and endogenous/integrated DNA. The suppression by ZNF511-PRAP1 is independent of DNA methylation and can be abolished by trichostatin A (TSA) treatment and knockdown of HDAC2 and/or ZNF511-PRAP1. Furthermore, ZNF511-PRAP1 interacts directly with HDAC2. Our results revealed that transfected plasmids are recognized by ZNF511-PRAP1 and suppressed by a repressor complex comprising ZNF511-PRAP1 and HDAC2 and suggest that ZNF511-PRAP1 could play a role as a potential molecular barrier in nonviral transgene expression.

Sulfated zirconia-lanthana (SO42−/ZrO2-La2O3) precursors were prepared by ultrasonic coprecipitation method and followed by aging at different temperature. The precursors were treated by 0.5 mol/L H2SO4. Samples of SO42−/ZrO2-La2O3 nano-crystalline catalysts were obtained by baking the treated precursors at different temperatures. The acidic properties of SO42−/ZrO2-La2O3 were tested by the Hammett indicator method. The phase composition, specific area, particle structure, and surface state were characterized by X-ray diffraction, BET, transmission electron microscopy, infrared spectrum, and X-ray photoelectron spectroscopy. The catalytic activities were estimated by esterification of acetic acid with glycerin. It was shown that the catalyst prepared by ultrasonic stirring and low temperature (−15°C) exhibited highly active sites and high catalytic property.

The influence of Cu and Mn substitution on the structure and magnetic properties of melt-spun Pr8Fe87-xB5Mx ribbons with 0

The use of near-infrared (NIR) spectroscopy to discriminate between uninfested seeds of Picea abies (L.) Karst and seeds infested with Plemeliella abietina Seitn (Hymenoptera, Torymidae) larva is sensitive to seed origin and year of collection. Five seed lots collected during different years from Sweden, Finland, and Belarus were used in this study. Initially, seeds were classified as infested or uninfested with X-radiography, and then, NIR spectra from single seeds were collected with a NIR spectrometer from 1100 to 2498 nm with a resolution of 2 nm. Discriminant models were derived by partial least squares regression using raw and orthogonal signal corrected spectra (OSC). The resulting OSC model developed on a pooled data set was more robust than the raw model and resulted in 100% classification accuracy. Once irrelevant spectral variations were removed by using OSC pretreatment, single-lot calibration models resulted in similar classification rates for the new samples irrespective of origin and year of collection. Dis criminant analyses performed with selected NIR absorption bands also gave nearly 100% classification rate for new samples. The origin of spectral differences between infested and uninfested seeds was attributed to storage lipids and proteins that were completely depleted in the former by the feeding larva.

Although it is impossible to manufacture identical columns for use in a simulated moving bed (SMB) process, theoretical studies assume that all the columns in an SMB unit have identical characteristics. In practice, calculations in modeling and optimization studies are made with the average values of each column parameter set. In this report, the effects on SMB process performance caused by column-to-column fluctuations of the parameters are discussed. As a first step, we show how the differences in porosity of the columns may be taken into account with a revised set of separation conditions. Reductions in the purity of the extract and the raffinate streams are quantitatively related to the column-to-column fluctuations of the retention times of the two components arising from these porosity differences. For the sake of simplicity, the discussion first addresses the case of a four-column SMB operating under linear conditions. Then, the scope is extended to the cases of SMB units incorporating several columns in each section and to SMB units operating under nonlinear conditions.

A new implementation of the equilibrium–dispersive model permits the study of problems requiring two-space dimensions for their modeling, such as a nonhomogeneous column with a cylindrical symmetry, a nonplanar injection with a cylindrical symmetry, or a cylindrical central injection. The migration and broadening of a cylindrical band coaxial with the column but narrower, moving along a homogeneous column is studied. The axial and radial profiles of the band inside the column and the elution profiles are calculated. These profiles depend on both the radial and the axial dispersion coefficients. The radial dispersion coefficient decreases with increasing mobile phase velocity and is usually low, much lower than the axial dispersion coefficient. Thus, the material in a relatively wide central injection made on a wide bore column may never have a chance to get close to the column wall. The clearance required at injection is estimated.

A Sorbex-type SMB separation instrument was operated for the separation of mixtures of 2-phenyl ethanol and 3-phenyl-1-propanol on a series of eight columns packed with Zorbax C18 bonded silica, using a 60:40 (v/v) solution of methanol and water as the mobile phase. The experiments were carried out with low-concentration mixtures under linear conditions. The elution profiles of both compounds between any two successive columns of the set under steady-state conditions were recorded while compositions of the raffinate and extract were measured. The four safety margin factors, β j , were divided into two groups: β 1 and β 4 ; β 2 and β 3 with different influence. Within the framework of the linear, ideal model of chromatography, a range of flow rates enables an SMB to operate successfully by completely separating the feed into its two components. The influence of different flow rates on the performance of the separator was studied by calculations and experiments with excellent agreement between both sets. With a simple optimization strategy, the four flow rates are selected to maximize the production rate or the concentration of extract and raffinate products, or to minimize the desorbent consumption. These optimum conditions are obtained by controlling the locations of concentration profiles inside the SMB. A reliable model for SMB operation allows a rapid and easy selection of the optimum experimental conditions.

A simulated moving bed (SMB) was operated for the separation of mixtures of 2-phenyl ethanol and 3-phenyl-1-propanol on columns packed with Zorbax C18 bonded silica, using a 60:40 (v/v) solution of methanol and water as the mobile phase. Series of four or eight columns were used. The experiments were carried out with low concentration mixtures, that is, under linear conditions. Band profiles of both compounds eluted from one of the columns during successive periods after steady state had been reached were recorded, as were the concentration histories at the extract and raffinate ports. These experimental results are compared to those predicted by two models: the linear ideal and the linear equilibrium-dispersive models of chromatography, applied to the SMB separator. These two models give excellent agreement between the experimental profiles and those calculated with the model. As expected, the profiles predicted by the ideal and the equilibrium-dispersive models differ only by the lack of dispersion in the profiles given by the former. The latter model is demonstrated to be a solid, reliable tool for further studies of the SMB design and optimization.

Columns were packed with alternating layers of virgin Zorbax C18 and blue colored Zorbax, treated with the dye Cibacron Blue. After consolidation of the column packing, the beds were extruded off the column, examined and photographed as they were, then cut along an axial plane, and these sections were examined and photographed. Evidence of radial heterogeneity of the distribution of the layers of the two packing materials in the bed after consolidation was observed. Friction of the bed along the column wall during consolidation was demonstrated.

Fundamental investigations of band profiles in nonlinear liquid chromatography have always assumed isothermal conditions. This is correct in linear, analytical chromatography, in which case the solute concentrations are very small and the influence of the heat of adsorption on the band profiles can always be neglected. However, this is no longer exact in nonlinear chromatography because the concentrations of the feed components are usually high. If the heat of adsorption is large enough, the chromatographic system cannot be considered as isothermal. The differential heat and mass balance equations are then coupled. Experimental data acquired in a typical case illustrate the effect. These data fit well to a lumped kinetic model with slow heat transfer kinetics. Further calculations suggest that the influence of the heat of adsorption on actual separations is small and could be negligible in almost all cases.

Simulated moving-bed (SMB) separators have been used successfully to separate or purify continuously two components with different adsorption selectivities. A detailed understanding of their behavior is still lacking, however. A numerical solution of the equilibrium—dispersive model allows the calculation of the concentration profiles along the columns, of their progressive shifts during a cycle, of the progressive build-up of these concentration profiles in each column during the start-up period, of the concentration profiles under steady-state and of the concentration histories at the extract and raffinate ports. These profiles are illustrated and discussed. The results obtained are compared to those of the exact analytical solution of the linear, ideal model previously developed. This comparison illustrates the influence of column efficiency on the time needed to reach steady-state operation.

The profiles of large-size system peaks and vacancies have been studied andcompared. A reversed-phase system was used with analytical-size column packed with ZORBAX C18 spherical particles and methanol-water as the mobile phase. The analyte was 3-phenyl-1-propanol. The equilibrium-dispersive model of chromatography was used to calculate band profiles using the measured isotherm data and the column efficiency. The isotherm data were determined using frontal analysis and could be fitted to a simple Langmuir equation. Excellent agreement was found between experimental and calculated results.

The elution band profiles of two partially separated components were calculated for a radially heterogeneous cylindrical column, using a modified equilibrium-dispersive model, assuming no radial dispersion. Steady-state flow-rate is assumed with a given cylindrical radial distribution of the velocity. The results show a marked degradation of the column performance when the ratio of the mobile-phase velocities at the column center and at the wall differs from unity by more than a few percent.

Performance and stability were tested for radial compression columns packed with spherical particles of an octadecyl bonded silica. The performance of the radial columns remained unchanged after approximately 500 h of constant use, including a number of solvent gradient runs. The performance of analytical columns packed with the same material was comparable to that of the radial columns. The column permeability decreases and the inlet pressure required to maintain a constant flow-rate increases with increasing radial compression pressure. Maximum column efficiency was obtained for a value of radial compression pressure approximately equal to 25 bar.

The onset of the nonlinear behavior of band profiles in elution chromatography is investigated by studying the profile of the shock layer caused by a finite mass transfer resistance in the absence of axial dispersion for a single component. A closed-form analytical expression of the shock layer is obtained for a parabolic isotherm. This solution depends on a dimensionless number which may be used to characterize the degree of nonlinear behavior of the band profiles and to select the model most appropriate for their accurate description. The profiles resulting from this solution are compared with those obtained by numerical calculations under different conditions to assess the influence of the assumptions made. The differences observed illustrate the sensitivity of the elution profiles to small changes in the equilibrium isotherm.

We here report a study of the correlation between the evolution of resistive switching and the oxygen vacancy configuration in La₀.₅Ca₀.₅MnO₃ (LCMO) based memristive devices. By taking advantage of LCMO located at a phase boundary of the metal-to-insulator transition, we observe the development of the high resistive states, depending upon not only the electrical pulse magnitude but also the switching cycles. We discuss the experimental results by an oxygen migration model that involves both single isolated and clustered oxygen vacancies, which are later verified using aberration-corrected scanning transmission electron microscopy.

According to the three-tier hardware architecture, BP neural network and fuzzy expert system we design a hollow fiber membrane fouling warning and intelligent control system, which can be realized on membrane fouling prediction, intelligent diagnosis and control. The system can effectively control the membrane systems with real-time operation; it can adjust system parameters with the water quality changes. It effectively inhibits membrane fouling, and reduces the off-line chemical cleaning of the membrane. With this, it can avoid physical and chemical damage, and extend membrane service life.