Phylogenetic analysis of porcine reproductive and respiratory syndrome virus in Vietnam, 2021.

The porcine reproductive and respiratory syndrome virus (PRRSV) causes more economic losses in the swine industry than any other virus. This study aimed to investigate the genetic diversity of PRRSV to assist in evaluating the effectiveness of PRRS vaccines. Twenty-eight samples from clinical cases were collected from 19 farms in seven provinces of Vietnam in 2021. Full-length PRRSV ORF5 genes from the 19 samples were amplified, sequenced, and compared to the corresponding sequences of referenced PRRSV strains from Genbank. The genetic analysis showed that 12 isolates were the highly pathogenic PRRSV subtype (HP-PRRSV) lineage 8, sublineage 8.7; six isolates were the classical North American PRRSV subtype (US-PRRSV), NADC-like group, lineage 1, sublineage 1.4, which were reported in Vietnam for the first time; and the final isolate was a vaccine-like strain. The field isolates of HP-PRRSV had relatively higher genetic diversity with US-PRRSV vaccine strains (84.0-94.5%) than HP-PRRSV vaccine strains (95.3-98.6%). Meanwhile, the six NADC-like isolates had low nucleotide similarity with US-PRRSV and HP-PRRSV vaccine strains (83.4-85.4% and 83.2-84.0%, respectively). Many amino acid substitutions were found in antigenic regions of GP5 involved in response to early antibody production, neutralizing antibodies, and viral immune evasion between these field strains and PRRSV vaccine strains. These findings provide insights into the molecular characteristics, genetic diversity, antigenicity, and evolution of PRRSV strains in Vietnam and postulate a compelling explanation for the limitations of current vaccination efforts.

Recent Advances in TiO2-Based Photocatalysts for Reduction of CO2 to Fuels.

Titanium dioxide (TiO2) has attracted increasing attention as a candidate for the photocatalytic reduction of carbon dioxide (CO2) to convert anthropogenic CO2 gas into fuels combined with storage of intermittent and renewable solar energy in forms of chemical bonds for closing the carbon cycle. However, pristine TiO2 possesses a large band gap (3.2 eV), fast recombination of electrons and holes, and low selectivity for the photoreduction of CO2. Recently, considerable progress has been made in the improvement of the performance of TiO2 photocatalysts for CO2 reduction. In this review, we first discuss the fundamentals of and challenges in CO2 photoreduction on TiO2-based catalysts. Next, the recently emerging progress and advances in TiO2 nanostructured and hybrid materials for overcoming the mentioned obstacles to achieve high light-harvesting capability, improved adsorption and activation of CO2, excellent photocatalytic activity, the ability to impede the recombination of electrons-holes pairs, and efficient suppression of hydrogen evolution are discussed. In addition, approaches and strategies for improvements in TiO2-based photocatalysts and their working mechanisms are thoroughly summarized and analyzed. Lastly, the current challenges and prospects of CO2 photocatalytic reactions on TiO2-based catalysts are also presented.

Recent Progress in Carbon-Based Buffer Layers for Polymer Solar Cells.

Carbon-based materials are promising candidates as charge transport layers in various optoelectronic devices and have been applied to enhance the performance and stability of such devices. In this paper, we provide an overview of the most contemporary strategies that use carbon-based materials including graphene, graphene oxide, carbon nanotubes, carbon quantum dots, and graphitic carbon nitride as buffer layers in polymer solar cells (PSCs). The crucial parameters that regulate the performance of carbon-based buffer layers are highlighted and discussed in detail. Furthermore, the performances of recently developed carbon-based materials as hole and electron transport layers in PSCs compared with those of commercially available hole/electron transport layers are evaluated. Finally, we elaborate on the remaining challenges and future directions for the development of carbon-based buffer layers to achieve high-efficiency and high-stability PSCs.

Silk Fibroin-Based Biomaterials for Biomedical Applications: A Review.

Since it was first discovered, thousands of years ago, silkworm silk has been known to be an abundant biopolymer with a vast range of attractive properties. The utilization of silk fibroin (SF), the main protein of silkworm silk, has not been limited to the textile industry but has been further extended to various high-tech application areas, including biomaterials for drug delivery systems and tissue engineering. The outstanding mechanical properties of SF, including its facile processability, superior biocompatibility, controllable biodegradation, and versatile functionalization have allowed its use for innovative applications. In this review, we describe the structure, composition, general properties, and structure-properties relationship of SF. In addition, the methods used for the fabrication and modification of various materials are briefly addressed. Lastly, recent applications of SF-based materials for small molecule drug delivery, biological drug delivery, gene therapy, wound healing, and bone regeneration are reviewed and our perspectives on future development of these favorable materials are also shared.

The preference-performance relationship as a means of classifying parasitoids according to their specialization degree.

Host range in parasitoids could be described by the preference-performance hypothesis (PPH) where preference is defined as host acceptance and performance is defined as the sum of all species on which parasitoid offspring can complete their life cycle. The PPH predicts that highly suitable hosts will be preferred by ovipositing females. However, generalist parasitoids may not conform to this hypothesis if they attack a large range of hosts of varying suitability. Under laboratory conditions, we tested the PPH relationship of three aphid parasitoids currently considered as generalist species (Aphelinus abdominalis, Aphidius ervi, Diaeretiella rapae). As expected, the three parasitoids species showed low selectivity, i.e., females stung all aphid species encountered (at least in some extent). However, depending on the parasitoid species, only 42%-58% of aphid species enabled producing parasitoid offspring. We did not find a correlation between the extent of preference and the performance of three generalist aphid parasitoids. For A. ervi, host phylogeny is also important as females showed higher attack and developmental rates on hosts closely related to the most suitable one. In addition, traits such as (a) the presence of protective secondary endosymbionts, for example, Hamiltonella defensa detected in Aphis fabae and Metopolophium dirhodum and (b) the sequestration of plant toxins as defense mechanism against parasitism, for example, in Aphis nerii and Brevicoryne brassicae, were likely at play to some extent in narrowing parasitoid host range. The lack of PPH relationship involved a low selectivity leading to a high adaptability, as well as selection pressure; the combination of which enabled the production of offspring in a new host species or a new environment. Testing for PPH relationships in parasitoids may provide useful cues to classify parasitoids in terms of specialization degree.

Light Absorption and Luminescence Quenching Properties of Hybrid Bulk Heterojunction Materials Based on the Blend Conducting Polymers.

We have investigated the enhancement absorption light and luminescence quenching properties of the hybrid bulk heterojunction systems which were fabricated using poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV); poly(3-hexylthiophene) (P3HT); fullerene derivative 1-(3-methoxycarbonyl) propyl-1-phenyl-[6,6] C61 (PCBM) and TiO2 nanocrystals. The optimized material showed a broad absorption in the region of 350 to 670 nm and the luminescence quenching higher 85%. The obtained results provide further insight into photophysics of the heterojunction system and device performance improvement by using this system as an active layer.

Culture and smoking among Vietnamese Americans in central Massachusetts.

The study was conducted (a) to assess use of any smoking cessation medications, (b) to identify factors associated with smoking, and (c) to assess knowledge of the health effects of smoking and attitudes toward smoking and seeking help for quitting among Vietnamese Americans. This is a descriptive study conducted with a nonrepresentative sample of 163 Vietnamese Americans. Current and former smokers constituted 24.4% and 25.6% of men and 1.2% and 3.5% of women, respectively. Of 20 current smokers, 17 (85%) reported use of cessation medications in their past quit attempts. Acculturation was the only significant correlate of ever smoking (vs. never smoking) in multivariate logistic regression analyses. Men who were less acculturated had more than 5 times the odds of being ever smokers (odds ratio = 5.33, 95% confidence interval = 1.37-20.78) compared with more acculturated men. Most participants had correct knowledge of the health effects of smoking regardless of age, education level, and smoking status. Attitudes toward smoking differed by age and education level but not by smoking status. Nurses working with Vietnamese Americans should be aware of the high rate of smoking among male immigrants and provide smoking cessation interventions.