In the past decade, research on nanofluids has been increased rapidly and reports reveal that nanofluids are beneficial heat transfer fluids for engineering applications. The heat transfer ...enhancement of nanofluids is primarily dependent on thermal conductivity of nanoparticles, particle volume concentrations and mass flow rates. Under constant particle volume concentrations and flow rates, the heat transfer enhancement only depends on the thermal conductivity of the nanoparticles. The thermal conductivity of nanoparticles may be altered or changed by preparing hybrid (composite) nanoparticles. Hybrid nanoparticles are defined as nanoparticles composed by two or more different materials of nanometer size. The fluids prepared with hybrid nanoparticles are known as hybrid nanofluids. The motivation for the preparation of hybrid nanofluids is to obtain further heat transfer enhancement with augmented thermal conductivity of these nanofluids. This review covers the synthesis of hybrid nanoparticles, preparation of hybrid nanofluids, thermal properties, heat transfer, friction factor and the available Nusselt number and friction factor correlations. The review also demonstrates that hybrid nanofluids are more effective heat transfer fluids than single nanoparticles based nanofluids or conventional fluids. Notwithstanding, full understanding of the mechanisms associated with heat transfer enhancement of hybrid nanofluids is still lacking and, consequently it is required a considerable research effort in this area.
Hand grip strength (HGS) is used for the diagnosis of sarcopenia and frailty. Several factors have been shown to influence HGS values during measurement. Therefore, variations in the protocols used ...to assess HGS, as part of the diagnosis of sarcopenia and frailty, may lead to the identification of different individuals with low HGS, introducing bias. The aim of this systematic review is to gather all the relevant studies that measured HGS to diagnose sarcopenia and frailty and to identify the differences between the protocols used.
A systematic review was carried out following the recommendations of The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. PubMed and Web of Science were systematically searched, until August 16, 2016. The evidence regarding HGS measurement protocols used to diagnose sarcopenia and frailty was summarised and the most recent protocols regarding the procedure were compared.
From the described search 4393 articles were identified. Seventy-two studies were included in this systematic review, in which 37 referred to sarcopenia articles, 33 to frailty and two evaluated both conditions. Most studies presented limited information regarding the protocols used.
The majority of the studies included did not describe a complete procedure of HGS measurement. The high heterogeneity between the protocols used, in sarcopenia and frailty studies, create an enormous difficulty in drawing comparative conclusions among them.
Temperate phages are bacterial viruses that as part of their life cycle reside in the bacterial genome as prophages. They are found in many species including most clinical strains of the human ...pathogens, Staphylococcus aureus and Salmonella enterica serovar Typhimurium. Previously, temperate phages were considered as only bacterial predators, but mounting evidence point to both antagonistic and mutualistic interactions with for example some temperate phages contributing to virulence by encoding virulence factors. Here we show that generalized transduction, one type of bacterial DNA transfer by phages, can create conditions where not only the recipient host but also the transducing phage benefit. With antibiotic resistance as a model trait we used individual-based models and experimental approaches to show that antibiotic susceptible cells become resistant to both antibiotics and phage by i) integrating the generalized transducing temperate phages and ii) acquiring transducing phage particles carrying antibiotic resistance genes obtained from resistant cells in the environment. This is not observed for non-generalized transducing temperate phages, which are unable to package bacterial DNA, nor for generalized transducing virulent phages that do not form lysogens. Once established, the lysogenic host and the prophage benefit from the existence of transducing particles that can shuffle bacterial genes between lysogens and for example disseminate resistance to antibiotics, a trait not encoded by the phage. This facilitates bacterial survival and leads to phage population growth. We propose that generalized transduction can function as a mutualistic trait where temperate phages cooperate with their hosts to survive in rapidly-changing environments. This implies that generalized transduction is not just an error in DNA packaging but is selected for by phages to ensure their survival.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The RNA-guided CRISPR-Cas9 nuclease from Streptococcus pyogenes (SpCas9) has been widely repurposed for genome editing. High-fidelity (SpCas9-HF1) and enhanced specificity (eSpCas9(1.1)) variants ...exhibit substantially reduced off-target cleavage in human cells, but the mechanism of target discrimination and the potential to further improve fidelity are unknown. Here, using single-molecule Förster resonance energy transfer experiments, we show that both SpCas9-HF1 and eSpCas9(1.1) are trapped in an inactive state when bound to mismatched targets. We find that a non-catalytic domain within Cas9, REC3, recognizes target complementarity and governs the HNH nuclease to regulate overall catalytic competence. Exploiting this observation, we design a new hyper-accurate Cas9 variant (HypaCas9) that demonstrates high genome-wide specificity without compromising on-target activity in human cells. These results offer a more comprehensive model to rationalize and modify the balance between target recognition and nuclease activation for precision genome editing.
There is growing evidence that vitamin D is related to chronic hepatitis C (CHC) pathogenicity. We analyzed the relationship of vitamin D status with advanced liver fibrosis (ALF) in CHC ...treatment‐naïve patients and sustained virologic response (SVR) in CHC patients on pegylated interferon alpha plus ribavirin (pegIFNα/ribavirin) therapy. We performed a meta‐analysis of all eligible studies published to date (April, 2014) in PubMed, SCOPUS, LILACS, and the Cochrane Library, assessing plasma/serum vitamin D levels related to ALF and/or SVR. Pooled odds ratios (ORs) were estimated by either fixed or random effects models. Fourteen studies were selected from the literature search, seven for ALF (1,083 patients) and 11 for SVR (2,672 patients). For liver fibrosis, low vitamin D status was related to a diagnosis of ALF, with the cutoffs of 10 ng/mL (OR = 2.37, 95% confidence interval CI = 1.20, 4.72) and 30 ng/mL (OR = 2.22, 95% CI = 1.24, 3.97) being significant, and a near‐significance for 20 ng/mL (OR = 1.44, 95% CI = 0.99, 2.12). Regarding SVR, a significant heterogeneity among studies was found (P < 0.001), and we only found a significant association with SVR for a vitamin D cutoff of 20 ng/mL (OR = 0.53, 95% CI = 0.31, 0.91). When meta‐analysis was performed excluding the outliers, significant pooled ORs were found for all patients (10 ng/mL OR = 0.48, 95% CI = 0.34, 0.67 and 20 ng/mL OR = 0.58, 95% CI = 0.45, 0.76) and GT1/4 patients (10 ng/mL OR = 0.53, 95% CI = 0.34, 0.81 and 20 ng/mL OR = 0.54, 95% CI = 0.39, 0.74). Conclusion: Low vitamin D status in CHC patients is associated with a higher likelihood of having ALF and lower odds of achieving SVR following pegIFNα/ribavirin therapy. (Hepatology 2014;60:1541–1550)
The presence of contaminants of emerging concern (CECs) in the environment has been recognized as a worldwide concern. In particular, water pollution by CECs is becoming a major global problem, which ...requires ongoing evaluation of water resources policies at all levels and the use of effective and innovative wastewaters treatment processes for their removal. Microalgae have been increasingly recognized as relevant for wastewater polishing, including CECs removal. These microorganisms are commonly cultivated in suspension. However, the use of planktonic microalgae for wastewater treatment has limitations in terms of microbiological contamination, process effectiveness and sustainability. The use of consortia of microalgae and bacteria represents a significant advance for sustainable wastewater polishing, particularly when the microorganisms are associated as biofilms. These immobilized mixed cultures can overcome the limitations of suspended-microalgae systems and improve the performance of the involved species for CECs removal. In addition, microalgae-bacteria based systems can offer a relevant combined effect for CECs removal and biomass production enhancement. This study reviews the advantages and advances on the use of microalgae for wastewater treatment, highlighting the potential on the use of microalgae-bacteria biofilms for CECs removal and the further biomass valorisation for third-generation biofuel production.
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•Contaminants of emerging concern (CECs) require effective treatment strategies.•The current water treatment methods are unsuccessful for CECs removal.•Microalgae-based bioremediation systems are promising for CECs removal.•Planktonic microalgae cultures are unsustainable.•Microalgae-bacteria biofilms can solve the limitations of planktonic cultures.
Vehicular acoustic noise evaluations are a concern of researchers due to health and comfort effects on humans and are fundamental for anyone interested in mitigating audio noise. This paper focuses ...on the evaluation of the noise level inside a vehicle by using statistical tools. First, an experimental setup was developed with microphones and a microcomputer located strategically on the car's panel, and measurements were carried out with different conditions such as car window position, rain, traffic, and car speed. Regression analysis was performed to evaluate the similarity of the noise level from those conditions. Thus, we were able to discuss the relevance of the variables that contribute to the noise level inside a car. Finally, our results revealed that the car speed is strongly correlated to interior noise levels, suggesting the most relevant noise sources are in the vehicle itself.
Olive agroecosystems have for several decades undergone management changes aimed to meet the demands of new agricultural policy trends and of consumers and society. While the main role of olive ...groves is the production of olives and oil, its multifunctional performance is supported through the European and regional legislative framework, promoting the recognition of non-productive ecosystem services provided by agriculture to society. The objective of this work is to compare two types of olive grove management (integrated and ecological) under the multifunctionality of agriculture (MFA) approach, in Estepa (Andalusia, Spain). To this end, environmental, economic and social indicators were considered. Subsequently, the multifunctional behaviour of olive groves under different management schemes was evaluated using the multicriteria Analytic Hierarchy Process (AHP) methodology. Ecological farming presented greater valuation in the satisfaction of social demands, with better weightings in all the indicators evaluated, except for farm income and Lepidoptera richness. Thus, the implementation of practices related to ecological management leads to a greater multifunctionality of olive groves. It is thus fundamental that multi-scale policies consider the value of the environmental externalities of this type of management, favouring its implementation to contribute positively to the multifunctionality and sustainability of olive groves in Andalusia.
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•A multifunctional analysis of olive groves with AHP was carried in south Spain.•Integrated olive groves showed a higher farm income than ecological olive groves.•Ecological management showed better results in social and environmental indicators.•Ecological farming contributes more in satisfying social demands to agriculture.•Political support is essential to guarantee the benefits of the ecological farming.
Abstract
Plasmids and temperate phages are key contributors to bacterial evolution. They are usually regarded as very distinct. However, some elements, termed phage–plasmids, are known to be both ...plasmids and phages, e.g. P1, N15 or SSU5. The number, distribution, relatedness and characteristics of these phage–plasmids are poorly known. Here, we screened for these elements among ca. 2500 phages and 12000 plasmids and identified 780 phage–plasmids across very diverse bacterial phyla. We grouped 92% of them by similarity of gene repertoires to eight defined groups and 18 other broader communities of elements. The existence of these large groups suggests that phage–plasmids are ancient. Their gene repertoires are large, the average element is larger than an average phage or plasmid, and they include slightly more homologs to phages than to plasmids. We analyzed the pangenomes and the genetic organization of each group of phage–plasmids and found the key phage genes to be conserved and co-localized within distinct groups, whereas genes with homologs in plasmids are much more variable and include most accessory genes. Phage–plasmids are a sizeable fraction of the sequenced plasmids (∼7%) and phages (∼5%), and could have key roles in bridging the genetic divide between phages and other mobile genetic elements.
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