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Porcine circoviruses (PCVs) are a significant cause of concern for swine health, with four genotypes currently recognized. Two of these, PCV3 and PCV4, have been detected in pigs across all age groups, in both healthy and diseased animals. These viruses have been associated with various clinical manifestations, including porcine dermatitis and nephropathy syndrome (PDNS) and respiratory and enteric signs. In this study, we detected PCV3 and PCV4 in central China between January 2022 and February 2023. We tested fecal swabs and tissue samples from growing-finishing and suckling pigs with or without respiratory and systemic manifestations and found the prevalence of PCV3 to be 15.15% (15/99) and that of PCV3/PCV4 coinfection to be 4.04% (4/99). This relatively low prevalence might be attributed to the fact that most of the clinical samples were collected from pigs exhibiting respiratory signs, with only a few samples having been obtained from pigs with diarrhea. In some cases, PCV2 was also detected, and the coinfection rates of PCV2/3, PCV2/4, and PCV2/3/4 were 6.06% (6/99), 5.05% (5/99), and 3.03% (3/99), respectively. The complete genomic sequences of four PCV3 and two PCV4 isolates were determined. All four of the PCV3 isolates were of subtype PCV3b, and the two PCV4 isolates were of subtype PCV4b. Two mutations (A24V and R27K) were found in antibody recognition domains of PCV3, suggesting that they might be associated with immune escape. This study provides valuable insights into the molecular epidemiology and evolution of PCV3 and PCV4 that will be useful in future investigations of genotyping, immunogenicity, and immune evasion strategies. [ABSTRACT FROM AUTHOR]

Polyhedral boranes are a class of well-known boron molecular clusters with unique physical and chemical properties, and great efforts have been made in the past decades to find more effective synthetic methods. However, the established synthetic methods suffer from low efficiency and low selectivity because the mechanism of the B–H bond condensation reaction, critical for the synthesis of the polyhedral boranes, is not well understood. Here we report highly selective and efficient synthetic methods of the salts of the tetradecahydridoundecaborate (1–) (B11H14−) and dodecahydrido-dodecaborates (2–) (B12H122−) anions by employing commercially available and inexpensive starting materials. Both theoretical and experimental investigations are carried out to elucidate the reaction mechanisms. We have found that the nature of the B–H bond condensation is the dihydrogen bonding interaction in which the positively charged hydrogens (bridged hydrogens) play a crucial role. The current study has not only led to more effective and selective synthetic methods for B11H14− and B12H122− but also unveiled the nature of the B–H bond condensation and the general formation mechanisms of polyhedral boranes. This finding will facilitate the development of more effective synthetic methods for polyhedral boranes and spur their wide application. [ABSTRACT FROM AUTHOR]

Porcine circovirus 4 (PCV4) is a recently discovered circovirus that was first reported in 2019 in several pigs in Hunan province of China and has also been identified in pigs infected with porcine epidemic diarrhea virus (PEDV). To further investigate the coinfection and genetic diversity of these two viruses, 65 clinical samples (including feces and intestinal tissues) were collected from diseased piglets on 19 large-scale pig farms in Henan province of China, and a duplex SYBR Green I–based quantitative real-time polymerase chain reaction (qPCR) assay was developed for detecting PEDV and PCV4 simultaneously. The results showed that the limit of detection was 55.2 copies/μL and 44.1 copies/μL for PEDV and PCV4, respectively. The detection rate for PEDV and PCV4 was 40% (26/65) and 38% (25/65), respectively, and the coinfection rate for the two viruses was 34% (22/65). Subsequently, the full-length spike (S) gene of eight PEDV strains and a portion of the genome containing the capsid (Cap) gene of three PCV4 strains were sequenced and analyzed. Phylogenetic analysis showed that all of the PEDV strains from the present study clustered in the G2a subgroup and were closely related to most of the PEDV reference strains from China from 2011 to 2021, but they differed genetically from a vaccine strain (CV777), a Korean strain (virulent DR1), and two Chinese strains (SD-M and LZC). It is noteworthy that two PEDV strains (HEXX-24 and HNXX-24XIA) were identified in one sample, and the HNXX-24XIA strain had a large deletion at amino acids 31-229 of the S protein. Moreover, a recombination event was observed in strain HEXX-24. Phylogenetic analysis based on the amino acid sequence of the PCV4 Cap protein revealed that PCV4 strains were divided into three genotypes: PCV4a1, PCV4a2, and PCV4b. Three strains in the present study belonged to PCV4a1, and they had a high degree of sequence similarity (>98% identity) to other PCV4 reference strains. This study not only provides technical support for field investigation of PEDV and PCV4 coinfection but also provides data for their prevention and control. [ABSTRACT FROM AUTHOR]

Porcine circovirus-like virus (PCLV) is a recently discovered virus that may be associated with diarrhea in pigs. To investigate the epidemic profile and genetic characteristics of this virus, 175 clinical samples (141 intestinal samples, 17 blood samples, and 17 fecal samples) were collected from diseased piglets during outbreaks of diarrhea from 33 pig farms in 19 cities of Henan and Shanxi provinces of China between 2016 and 2021 and were screened by PCR for the presence of PCLV. The results showed that the positive rate for PCLV was 32% (56/175) at the sample level, 60.6% (20/33) at the farm level, and 57.9% (11/19) at the city level, which varied from 5.88% to 44.12% between 2016 and 2021. It was also found that PCLV occurred in coinfections with porcine circovirus type 2 (PCV2), PCV3, PCV4, porcine epidemic diarrhea virus, and porcine reproductive and respiratory syndrome virus, but no nucleic acids were detected for transmissible gastroenteritis virus, porcine deltacoronavirus, or porcine rotavirus in piglets with diarrhea. Notably, PCLV was detected in 13 diarrheal piglets from four different farms that were negative for the other porcine viruses. These findings suggest that PCLV may be associated with porcine diarrhea and that it has been circulating in piglets in Henan and Shanxi provinces of China. In addition, the complete genomes of 13 PCLV strains were sequenced and found to share 35.4%–91.0% nucleotide sequence identity with sequences available in the GenBank database. Phylogenetic analysis based on Rep amino acid sequences revealed that the 13 PCLV strains from this study clustered in group 1 and were closely related to eight Chinese PCLV strains, Bo-Circo-like virus CH, American strains 21 and 22, and Hungarian strains 288_4 and 302_4, but they differed genetically from seven other foreign PCLV strains. The whole genome and rep gene of 13 PCLV strains in this study were 72.2%-82% and 83.8%-89.7% identical, respectively, to those of Bo-Circo-like virus strain CH, indicating that PCLV is a novel virus in pigs that may be involved in cross-species transmission. Evidence of a recombination event was found in the rep region of the 13 PCLV strains sequenced. This study enriches the epidemiological data on PCLV infection in pigs in China and lays a foundation for further study on the pathogenesis of PCLV. [ABSTRACT FROM AUTHOR]

The dynamical transmission of intermediate-energy protons through a polycarbonate (PC) conical capillary with taper angle from 0.48° to 2° are simulated. The results show that for small taper angle of 0.48°, the transmission of 100 keV protons is dominated by the deposited-charge-assisted specular reflection. This reflection effect decreases with the increase of the taper angle. When the taper angle is increased to 2°, the transmission of the protons is mainly influenced by small angle scattering, which is consistent with the experimental data. The asymptotic transmission rate decreases with the increase of the capillary taper angle. These results suggest that the deposited-charge-assisted specular reflection is significant in focusing several-hundred-keV protons. [ABSTRACT FROM AUTHOR]