Pd-based nanocatalysts (NCs) are the potential substitutes for the Pt-based NCs used in the direct methanol fuel cells (DMFCs) because of their lower cost and comparable catalytic performance. The ...catalytic performance of Pd-based NCs is highly connected with the morphology, composition and surface structure of the catalysts. Here, solid bimetallic PdAu and hollow PdAu NCs were synthesized by a successive reduction and co-reduction method, respectively, using P123 both as reducing reagent and protectant. Compared with the solid PdAu NCs and commercial Pd black catalyst, the hollow PdAu NCs exhibited enlarged electrochemical surface areas (ECSA), and showed an enhanced electrocatalytic activity and stability for methanol oxidation reaction (MOR) in alkaline solution. The excellent electrocatalytic performance is contributed to the unique hollow structure and alloy effects of the PdAu NCs.
•Hollow PdAu NCs were synthesized successfully by a successive reduction method.•The morphology, alloy degree and composition of the PdAu NCs can be well controlled.•Hollow PdAu NCs showed an enlarged ECSA and improved performance for CH3OH oxidation.
The structure-activity relationship between the morphology and composition of Pd-based nanocatalysts is an important fundamental issue in direct methanol fuel cells (DMFC). Three dimensional (3D) ...netlike Pd–Rh bimetallic catalysts with different atomic ratios (Pd1Rh3, PdRh, Pd3Rh1) are synthesized through a simple wet chemical way using P123 as a reducing agent and KBr as morphological regulator. The morphology, structure and composition of the catalysts are proved by a series of physicochemical test technology. It is shown that the 3D-netlike structure is composed of short self-assembly nanochains. Electrochemical results display that their application towards methanol oxidation reaction (MOR) in alkaline solution. The MOR activity of the optimized Pd3Rh1 nanocatalyst is improved to about 4.0 mA cm−2, which is much higher than that of the commercial Pd/C catalyst.
•Three dimensional (3D) netlike PdRh NCs were synthesized by a simple way.•The 3D netlike structure may be due to the combined action of P123 and Br ion.•The 3D netlike PdRhNCs showed an enhanced performance for CH3OH oxidation.
The coronavirus disease 2019 (COVID-19) pandemic continues to pose a global threat to the human population. Identifying animal species susceptible to infection with the SARS-CoV-2/ HCoV-19 pathogen ...is essential for controlling the outbreak and for testing valid prophylactics or therapeutics based on animal model studies. Here, different aged Chinese tree shrews (adult group, 1 year old; old group, 5-6 years old), which are close relatives to primates, were infected with SARS-CoV-2. X-ray, viral shedding, laboratory, and histological analyses were performed on different days post-inoculation (dpi). Results showed that Chinese tree shrews could be infected by SARS-CoV-2. Lung infiltrates were visible in X-ray radiographs in most infected animals. Viral RNA was consistently detected in lung tissues from infected animals at 3, 5, and 7 dpi, along with alterations in related parameters from routine blood tests and serum biochemistry, including increased levels of aspartate aminotransferase (AST) and blood urea nitrogen (BUN). Histological analysis of lung tissues from animals at 3 dpi (adult group) and 7 dpi (old group) showed thickened alveolar septa and interstitial hemorrhage. Several differences were found between the two different aged groups in regard to viral shedding peak. Our results indicate that Chinese tree shrews have the potential to be used as animal models for SARS-CoV-2 infection.
Purpose
Early recurrence (ER) after surgery is related to early death in patients with hepatocellular carcinoma (HCC) after radical resection. To explore the role of preoperative contrast-enhanced ...ultrasound (CEUS) in predicting ER of HCC after curative resection and to stratify the risk of ER.
Materials and methods
This study evaluated consecutive 556 patients with HCC who were examined by CEUS during the 2 weeks before curative resection between January 2011 and December 2018. ER was defined as intrahepatic and/or extrahepatic recurrence within 2 year after resection of HCC. Univariate and logistic regression analyses were performed to identify independent risk factors for ER after surgical resection of HCC. Recurrence-free time (RFS) rates were analyzed and compared by log-rank test.
Results
ER occurred in 307 (55.2%) of the 556 patients. Univariate and multivariate analyses revealed that a tumor size ≥ 30 mm and satellite nodules seen on CEUS, DL(deep learning) radiomics reoccurrence score based on the frame of image with the maximum intensity of CEUS and an elevated alpha-fetoprotein level were significantly associated with ER (
P
< .05). Based on the number of predictors present, patients with CEUS LR-5 HCC were stratified into three risk subgroups: risk group 3 (high-risk patients, 4 predictors), risk group 2 (medium-risk patients, 2–3 predictors), and risk group 1 (low-risk patients, 0–1 predictor). The 2-year RFS rate was 19.4% in risk group 3, 40.9% in risk group 2, and 48.1% in risk group 1; the corresponding mean RFS times were 14.0 ± 2.9 months, 43.7 ± 6.6 months, and 55.5 ± 2.8 months, respectively (
P
< .001).
Conclusions
Tumor size ≥ 30 mm and satellite nodules seen on CEUS, DL radiomics reoccurrence score based on the frame of image with the maximum intensity of CEUS and an elevated alpha-fetoprotein level can predict ER of HCC.
CC-chemokine receptor 5 (CCR5) is an attractive target for preventing the entry of human immunodeficiency virus 1 (HIV-1) into human host cells. Maraviroc is the only CCR5 antagonist, and it was ...marketed in 2007. To overcome the shortcomings of maraviroc, structure-based drug design was performed to minimize CYP450 inhibition and to enhance anti-HIV potency and bioavailability. Thirty-four novel 1-heteroaryl-1,3-propanediamine derivatives (1–34) were synthesized, displaying CCR5-antagonist activities in the 2.3–296.4 nM range. Among these, compounds 21 and 34 were the most potent CCR5 antagonists, with excellent in vitro anti-HIV-1 activity, low cytotoxicity, and an acceptable pharmacokinetic profile. Furthermore, the X-ray crystal structures of compounds 21 and 34 bound to CCR5 were determined at 2.8 Å resolution. Compound 34 exhibited no CYP450-inhibition activity at 25 μM, which overcomes the potential drug–drug interaction of maraviroc. Compound 34 represents a promising drug candidate for HIV-infection treatment.
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•Characterization of Chitosan from novel marine source by Solid state NMR and MALDI-TOF analysis.•Dolutegravir loaded polymeric nanoparticle developed by Spray drying technique with ...small size and high drug loading.•Cytotoxicity and anti-HIV activity of Nanoparticle was evaluated using Human Lymphatic cell line (C8166).•Nanoparticle tested for milk admixture in-vitro.
The present study aims to develop Chitosan-based polymeric nanoparticles of anti-HIV drug Dolutegravir, to aid appropriate dose adjustment and ease of oral administration as milk and food admixture for children. The isolated Chitosan from the crab shell species Portunus Sanguinolentus has been characterized for their physicochemical properties. Nanoparticles were developed with varying ratio of drug: Chitosan and assessed for particle size (140−548 nm), zeta potential (+26.1 mV) with a maximum of 75 % drug content. Nanoparticles exhibited improved stability and drug release in the 0.1 N HCl medium compared to pure drug. The MTT assay and the Syncytia inhibition assay in C8166 (T-lymphatic cell line) infected with HIVIIIB viral strain, which showed better therapeutic efficiency and lesser cytotoxicity compared to the pure drug. In consonance with the data obtained, the use of chitosan from a novel source for drug delivery carrier has opened exceptional prospects for delivering drugs efficiently to paediatrics
The emerging SARS-CoV-2 variants, commonly with many mutations in S1 subunit of spike (S) protein are weakening the efficacy of the current vaccines and antibody therapeutics. This calls for the ...variant-proof SARS-CoV-2 vaccines targeting the more conserved regions in S protein. Here, we designed a recombinant subunit vaccine, HR121, targeting the conserved HR1 domain in S2 subunit of S protein. HR121 consisting of HR1-linker1-HR2-linker2-HR1, is conformationally and functionally analogous to the HR1 domain present in the fusion intermediate conformation of S2 subunit. Immunization with HR121 in rabbits and rhesus macaques elicited highly potent cross-neutralizing antibodies against SARS-CoV-2 and its variants, particularly Omicron sublineages. Vaccination with HR121 achieved near-full protections against prototype SARS-CoV-2 infection in hACE2 transgenic mice, Syrian golden hamsters and rhesus macaques, and effective protection against Omicron BA.2 infection in Syrian golden hamsters. This study demonstrates that HR121 is a promising candidate of variant-proof SARS-CoV-2 vaccine with a novel conserved target in the S2 subunit for application against current and future SARS-CoV-2 variants.
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The electrocatalytic activity and stability of CoAuPd nanocatalysts for MOR can be improved more effectively by heat treatment followed dealloying process.
•Dealloying and heat ...treatment methods are combined to regulate catalytic activity and stability.•Ordered and intermetallic CoAuPd compounds could be obtained by heat treatment.•Dealloying after heat treatment can enhance the stability of the catalyst more effectively.
Dealloying and heat treatment methods are combined to regulate the surface structure of CoAuPd nanocatalysts (NCs), and improve their activity and stability for methanol oxidation. The effect of the sequence of the two methods on the structure-activity-stability relationship is investigated and optimized. CoAuPd-1 and CoAuPd-3 NCs were prepared by simple co-reduction and successive reduction method, respectively. The CoAuPd NCs obtained by dealloying after heat treatment (CoAuPd-HD) have better dispersity, larger electrochemical active surface area (ECSA), higher activity, stability, and anti-CO poisoning durability. The mass and specific activity of CoAuPd-3-HD are 333.478 mA mgPd−1 and 1.109 mA cm−2, respectively, which are higher than the CoAuPd-3 obtained by heat treatment after dealloying (CoAuPd-3-DH). The current densities of CoAuPd-3-DH and CoAuPd-3-HD remain 44.6 and 80.7% after 500 cycles, respectively, indicating that dealloying after heat treatment can significantly enhance the stability. The combination of heat treatment and dealloying is expected to provide a new idea for the design of low Pd, Pt-based catalysts with high activity and stability.
Eight extant species of pangolins are currently recognized. Recent studies found that two mitochondrial haplotypes identified in confiscations in Hong Kong could not be assigned to any known pangolin ...species, implying the existence of a species. Here, we report that two additional mitochondrial haplotypes identified in independent confiscations from Yunnan align with the putative species haplotypes supporting the existence of this mysterious species/population. To verify the new species scenario we performed a comprehensive analysis of scale characteristics and 138 whole genomes representing all recognized pangolin species and the cryptic new species, 98 of which were generated here. Our morphometric results clearly attributed this cryptic species to Asian pangolins (
sp.) and the genomic data provide robust and compelling evidence that it is a pangolin species distinct from those recognized previously, which separated from the Philippine pangolin and Malayan pangolin over 5 Mya. Our study provides a solid genomic basis for its formal recognition as the ninth pangolin species or the fifth Asian one, supporting a new taxonomic classification of pangolins. The effects of glacial climate changes and recent anthropogenic activities driven by illegal trade are inferred to have caused its population decline with the genomic signatures showing low genetic diversity, a high level of inbreeding, and high genetic load. Our finding greatly expands current knowledge of pangolin diversity and evolution and has vital implications for conservation efforts to prevent the extinction of this enigmatic and endangered species from the wild.
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