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Considering that the crystallographic characteristics of the Sb-rich secondary phase particles (SPPs) greatly affect the thermoelectric properties of Bi2Te3 based materials, it is of great significance to explore the mechanism behind the Sb-rich SPPs in the p-type (Bi, Sb)2Te3 material. Here a conventional TEM technique was used to characterize the composition, size and distribution of Sb-rich SPPs in a spark plasma sintered p-type (Bi, Sb)2Te3 alloy. The results indicated that two different morphologies of Sb-rich SPPs including elongated and circular Sb-rich SPPs were frequently observed. Combined with high-resolution transmission electron microscopy, this work provides atomic-scale evidence for the formation mechanism behind the Sb-rich SPPs in the (Bi, Sb)2Te3 material.
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BACKGROUND: Co-infection with other pathogens in coronavirus disease 2019 (COVID-19) patients exacerbates disease severity and impacts patient prognosis. Clarifying the exact pathogens co-infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is premise of the precise treatment for COVID-19 patients. METHODS: Sputum samples were collected from 17 patients in the COVID-19 positive group and 18 patients in the COVID-19 negative group. DNA extraction was performed to obtain the total DNA. Sequencing analysis using 16S and ITS rRNA gene was carried out to analyze the composition of bacterial and fungal communities. Meanwhile, all the samples were inoculated for culture. RESULTS: We did not observe significant differences in bacterial composition between the COVID-19 positive and negative groups. However, a significantly higher abundance of Candida albicans was observed in the upper respiratory tract samples from the COVID-19 positive group compared to the COVID-19 negative group. Moreover, the Candida albicans strains isolated from COVID-19 positive group exhibited impaired secretion of aspartyl proteinases. CONCLUSION: COVID-19 positive patients demonstrate a notable increase in the abundance of Candida albicans, along with a decrease in the levels of aspartyl proteinases, indicating the alteration of microbiota composition of upper respiratory tract.
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Bactérias , COVID-19 , Candida albicans , Microbiota , Sistema Respiratório , SARS-CoV-2 , Escarro , Humanos , COVID-19/microbiologia , COVID-19/virologia , Microbiota/genética , Masculino , Candida albicans/isolamento & purificação , Candida albicans/genética , Feminino , Escarro/microbiologia , Escarro/virologia , Pessoa de Meia-Idade , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Bactérias/classificação , Bactérias/isolamento & purificação , Bactérias/genética , Sistema Respiratório/microbiologia , Sistema Respiratório/virologia , Idoso , RNA Ribossômico 16S/genética , Adulto , Coinfecção/microbiologia , Coinfecção/virologiaRESUMO
The objective of this review was to provide quantitative insights into algal growth and nutrient removal in anaerobic digestate. To synthesize the relevant literature, a meta-analysis was conducted using data from 58 articles to elucidate key factors that impact algal biomass productivity and nutrient removal from anaerobic digestate. On average, algal biomass productivity in anaerobic digestate was significantly lower than that in synthetic control media (p < 0.05) but large variation in productivity was observed. A mixed-effects multiple regression model across study revealed that biological or chemical pretreatment of digestate significantly increase productivity (p < 0.001). In contrast, the commonly used practice of digestate dilution was not a significant factor in the model. High initial total ammonia nitrogen suppressed algal growth (p = 0.036) whereas initial total phosphorus concentration, digestate sterilization, CO2 supplementation, and temperature were not statistically significant factors. Higher growth corresponded with significantly higher NH4-N and phosphorus removal with a linear relationship of 6.4 mg NH4-N and 0.73 mg P removed per 100 mg of algal biomass growth (p < 0.001). The literature suggests that suboptimal algal growth in anaerobic digestate could be due to factors such as turbidity, high free ammonia, and residual organic compounds. This analysis shows that non-dilution approaches, such as biological or chemical pretreatment, for alleviating algal inhibition are recommended for algal digestate treatment systems.
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Amônia , Microalgas , Anaerobiose , Nutrientes , Biomassa , Fósforo , NitrogênioRESUMO
FeâNâC is the most promising alternative to platinum-based catalysts to lower the cost of proton-exchange-membrane fuel cell (PEMFC). However, the deficient durability of FeâNâC has hindered their application. Herein, a TiN-doped FeâNâC (FeâNâC/TiN) is elaborately synthesized via the sol-gel method for the oxygen-reduction reaction (ORR) in PEMFC. The interpenetrating network composed by FeâNâC and TiN can simultaneously eliminate the free radical intermediates while maintaining the high ORR activity. As a result, the H2O2 yields of FeâNâC/TiN are suppressed below 4%, ≈4 times lower than the FeâNâC, and the half-wave potential only lost 15 mV after 30 kilo-cycle accelerated durability test (ADT). In a H2âO2 fuel cell assembled with FeâNâC/TiN, it presents 980 mA cm-2 current density at 0.6 V, 880 mW cm-2 peak power density, and only 17 mV voltage loss at 0.80 A cm-2 after 10 kilo-cycle ADT. The experiment and calculation results prove that the TiN has a strong adsorption interaction for the free radical intermediates (such as *OH, *OOH, etc.), and the radicals are scavenged subsequently. The rational integration of Fe single-atom, TiN radical scavenger, and highly porous network adequately utilize the intrinsic advantages of composite structure, enabling a durable and active Pt-metal-free catalyst for PEMFC.
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BACKGROUND: Gastric cancer (GC) accounts for the greatest disparity in cancer mortality between Black and White Americans. Although clinical trials have shown that Helicobacter pylori (Hp) treatment reduces risk of GC, Hp testing and treatment is not consistently performed in the US, and may offer an opportunity to improve survival. METHODS: In a diverse retrospective cohort of 99 GC cases diagnosed at Duke University from 2002-2020 (57% Black; 43% white), we examined the association of Hp testing and treatment prior to or at cancer diagnosis with overall survival using Cox regression analyses to calculate adjusted hazards ratios (HRs) and 95% confidence intervals (CIs). RESULTS: Overall, 62% of patients were tested for Hp prior to or at GC diagnosis. Of those, 25% tested positive and were treated < 1 year prior to or at diagnosis, 15% tested positive and were treated ≥ 1 year prior to diagnosis, 6% tested positive without evidence of treatment, and 54% tested negative. Compared to never tested, Hp testing and treatment < 1 year prior to or at diagnosis was associated with a significantly reduced likelihood of death (HR 0.21, 95% CI 0.08-0.58). The benefit of any Hp test and treat prior to or at GC diagnosis was significant even among stage IV patients only (HR, 0.22; 95% CI 0.05-0.96). CONCLUSIONS: These findings support Hp testing and treatment for patients at risk of or diagnosed with GC, and suggest Hp treatment may provide an opportunity to reduce GC mortality disparities in the US.
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Infecções por Helicobacter , Helicobacter pylori , Neoplasias Gástricas , Humanos , Neoplasias Gástricas/epidemiologia , Estudos Retrospectivos , Infecções por Helicobacter/diagnóstico , Infecções por Helicobacter/tratamento farmacológico , Infecções por Helicobacter/complicações , Modelos de Riscos ProporcionaisRESUMO
Twin boundaries provide a strong phonon scattering center to hinder the lattice thermal conductivity in thermoelectric materials, but the underlying evolution process of deformation twinning remains to be figured out. By applying atomic resolution transmission electron microscope (TEM) observations, a novel type of transitional structure of {0001} twin was observed, for the first time, in the p-type (Bi,Sb)2Te3 alloy subjected to three-point bending deformation. The transformation from matrix to (0001) twin can be realized by the following path: matrix â transitional twin â (0001) twin, and this process was completed by the gliding of a total of four partial dislocations (b1 = 1/3[011Ì0]) extended in the different (0001) planes. This new finding here will shed light on the nucleation and growth of deformation twins in the p-type (Bi, Sb)2Te3 alloy.
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Diabetic foot infections are a common complication of diabetes. Staphylococcus aureus is frequently isolated from diabetic foot infections and commonly colonizes human nares. According to the study, the nasal microbiome analysis revealed that diabetic patients had a significantly altered nasal microbial composition and diversity. Typically, the fasting blood glucose (FBG) level had an impact on the abundance and sequence type (ST) of S. aureus in diabetic patients. We observed that highly virulent S. aureus ST7 strains were more frequently colonized in diabetic patients, especially those with poorly controlled FBG, while ST59 was dominant in healthy individuals. S. aureus ST7 strains were more resistant to human antimicrobial peptides and formed stronger biofilms than ST59 strains. Critically, S. aureus ST7 strains displayed higher virulence compared to ST59 strains in vivo. The dominance of S. aureus ST7 strains in hyperglycemic environment is due to the higher activity of the SaeRS two-component system (TCS). S. aureus ST7 strains outcompeted ST59 both in vitro, and in nasal colonization model in diabetic mice, which was abolished by the deletion of the SaeRS TCS. Our data indicated that highly virulent S. aureus strains preferentially colonize diabetic patients with poorly controlled FBG through SaeRS TCS. Detection of S. aureus colonization and elimination of colonizing S. aureus are critical in the care of diabetic patients with high FBG.
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Diabetes Mellitus Experimental , Pé Diabético , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Humanos , Animais , Camundongos , Staphylococcus aureus , Diabetes Mellitus Experimental/complicações , Nariz , Cavidade NasalRESUMO
OBJECTIVES: To determine the genomic features of IMP-4-producing Klebsiella pneumoniae isolates recovered from paediatric patients and the transmission dynamics of blaIMP-4. METHODS: IMP-producing K. pneumoniae isolates were collected from paediatric patients in Shanghai Children's Medical Center from 2013 to 2020. WGS was performed for all isolates, and the complete genomes of three IMP-4-producing isolates were generated. The distribution of blaIMP-4-harbouring plasmids was determined, and a conjugation assay was employed to investigate the horizontal transfer of blaIMP-4-harbouring plasmids. RESULTS: We collected 21 blaIMP-carrying K. pneumoniae isolates, with IMP-4 (16/21, 76.2%) as the predominant subtype, followed by IMP-8 (nâ=â3) and IMP-26 (nâ=â2). IMP-4-producing isolates displayed a diverse population structure and all blaIMP-4 genes were located on plasmids, including IncN (nâ=â9), IncHI5 (nâ=â5), IncFII(K) (nâ=â1) and IncFII(pKP91) (nâ=â1), although only IncN plasmids were conjugative. Clonal transmission of ST101 strains carrying IncHI5 blaIMP-4-harbouring plasmids was observed, and the acquisition of blaIMP-4 by the international high-risk ST101 clone constituted a novel combination of ST101 clone and carbapenemase genes. Plasmid analysis demonstrated that the conjugal transfer of the IncHI5 blaIMP-4-harbouring plasmid might be blocked by the ST101 bacterial host. CONCLUSIONS: The horizontal transfer of IncN plasmids and clonal spread of the international high-risk ST101 clone facilitated the nosocomial dissemination of blaIMP-4 among K. pneumoniae. The emerging IMP-4-producing ST101 clone displays diverse combinations of carbapenemase genes, and this clone could be a continually evolving threat and warrants prospective monitoring.
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Infecção Hospitalar , Infecções por Enterobacteriaceae , Infecções por Klebsiella , Humanos , Criança , Klebsiella pneumoniae/genética , Infecções por Enterobacteriaceae/microbiologia , Transferência Genética Horizontal , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Estudos Prospectivos , China/epidemiologia , beta-Lactamases/genética , Plasmídeos/genética , Proteínas de Bactérias/genética , Infecções por Klebsiella/epidemiologia , Testes de Sensibilidade Microbiana , AntibacterianosRESUMO
We identified a novel ceftazidime/avibactam resistance mechanism in sequence type 11 Klebsiella pneumoniae carbapenemase 2-producing K. pneumoniae. Plasmid recombination and chromosomal integration formed a novel virulence plasmid and provided an additional promoter for blaSHV-12, leading to blaSHV-12 overexpression and ceftazidime/avibactam resistance. Genetic rearrangement contributed to convergence of hypervirulence and ceftazidime/avibactam resistance.
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Enterobacteriáceas Resistentes a Carbapenêmicos , Infecções por Klebsiella , Humanos , Ceftazidima/farmacologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Klebsiella pneumoniae/genética , Infecções por Klebsiella/epidemiologia , Infecções por Klebsiella/tratamento farmacológico , Proteínas de Bactérias/genética , beta-Lactamases/genética , Testes de Sensibilidade MicrobianaRESUMO
Sustainable zinc-air batteries (ZABs) are considered promising energy storage devices owing to their inherent safety, high energy density, wide operating temperature window, environmental friendliness, etc., showing great prospect for future large-scale applications. Thus, tremendous efforts have been devoted to addressing the critical challenges associated with sustainable ZABs, aiming to significantly improve their energy efficiency and prolong their operation lifespan. The growing interest in sustainable ZABs requires in-depth research on oxygen electrocatalysts, electrolytes, and Zn anodes, which have not been systematically reviewed to date. In this review, the fundamentals of ZABs, oxygen electrocatalysts for air cathodes, physicochemical properties of ZAB electrolytes, and issues and strategies for the stabilization of Zn anodes are systematically summarized from the perspective of fundamental characteristics and design principles. Meanwhile, significant advances in the in situ/operando characterization of ZABs are highlighted to provide insights into the reaction mechanism and dynamic evolution of the electrolyte|electrode interface. Finally, several critical thoughts and perspectives are provided regarding the challenges and opportunities for sustainable ZABs. Therefore, this review provides a thorough understanding of the advanced sustainable ZAB chemistry, hoping that this timely and comprehensive review can shed light on the upcoming research horizons of this prosperous area.
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PURPOSE: Gastric cancer remains a racial health disparity in the US, but few studies have examined supplements as a potential protective factor. We examined associations between regular supplement use and gastric cancer risk among the predominantly Black participants in the Southern Community Cohort Study (SCCS). METHODS: Of the 84,508 individuals recruited in the SCCS from 2002 to 2009, 81,884 responded to the baseline question: any vitamin or supplement taken at least once per month in the past year. Secondary analyses assessed specific supplement use. Associations with incident gastric cancer were examined using adjusted Cox proportional hazards models, stratified by histologic subtype and secondarily by healthy eating index (HEI). RESULTS: Approximately half of the participants (47%, n = 38,318) reported any regular supplement use. Among the 203 incident gastric cancers over the follow-up period (median, 7 years), 142 were non-cardia (NCGC), 31 cardia (CGC), and 30 unknown. Regular supplement use was associated with a 30% decreased risk of NCGC (hazards ratio (HR) 0.70; 95% confidence interval (CI) 0.49-0.99). Among participants below the HEI median, any regular supplement and multivitamin use were associated with a 52% and 70% decrease in risk of NCGC (HR 0.48; 95%CI 0.25-0.92 and HR 0.30; 95%CI 0.13-0.71), respectively. No associations were found for CGC. CONCLUSION: Regular supplement use, including multivitamins, was associated with a decreased risk of NCGC in the SCCS, particularly among participants with a lower quality diet. Inverse associations of supplement use and NCGC incidence provide support for clinical trials among high-risk populations in the US.
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Neoplasias Gástricas , Humanos , Estudos de Coortes , Neoplasias Gástricas/epidemiologia , Suplementos Nutricionais , Fatores de Risco , VitaminasRESUMO
Robust operation of Zn-air batteries (ZABs) with high capacity and excellent energy efficiency is desirable for practical harsh applications, whose bottlenecks are mainly originated from the sluggish oxygen catalytic kinetics and unstable Zn|electrolyte interface. In this work, we synthesized the edge-hosted Mn-N4-C12 coordination supported on N-doped defective carbon (Mn1/NDC) catalyst, exhibiting a good bifunctional performance of the oxygen reduction/evolution reaction (ORR/OER) with a low potential gap of 0.684 V. Theoretical calculation reveals that the edge-hosted Mn-N4-C12 coordination displayed the lowest overpotential of the ORR/OER owing to the decreased adsorption free energy of OH*. The Mn1/NDC-based aqueous ZABs deliver impressive rate performance, ultralong discharging lifespan, and excellent stability. Notably, the assembled solid-state ZABs demonstrate a high capacity of 1.29 Ah, a large critical current density of 8 mA cm-2, and robust cycling stability with excellent energy efficiency at -40 °C, which should be attributed to the good bifunctional performance of Mn1/NDC and anti-freezing solid-state electrolyte (SSE). Meanwhile, the zincophilic nanocomposite SSE with high polarity accounts for the stable Zn|SSE interface compatibility. This work not only highlights the importance of the atomic structure design of oxygen electrocatalysts for ultralow-temperature and high-capacity ZABs but also spurs the development of sustainable Zn-based batteries at harsh conditions.
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Staphylococcus aureus is a high-virulent Gram-positive pathogen that is responsible for a serious of diseases. The emergence of antibiotic-resistant S. aureus poses a significant challenge in terms of treatment. The recent research on the human microbiome suggested that the application of commensal bacteria is a new strategy for combating pathogenic infections. Staphylococcus epidermidis, one of the most abundant species in the nasal microbiome, is able to inhibit the colonization of S. aureus. However, during bacterial competition, S. aureus undergoes evolutionary changes to adapt to the diverse environment. Our study has demonstrated that the nasal colonized S. epidermidis possesses the ability to inhibit the hemolytic activity of S. aureus. Moreover, we deciphered another layer of mechanism to inhibit S. aureus colonization by S. epidermidis. The active component present in the cell-free culture of S. epidermidis was found to significantly reduce the hemolytic activity of S. aureus in SaeRS- and Agr-dependent manner. Specifically, the hemolytic inhibition on the S. aureus Agr-I type by S. epidermidis is primarily dependent on the SaeRS two-component system. The active component is characterized as a small molecule that is heat sensitive and protease resistant. Critically, S. epidermidis significantly inhibit the virulence of S. aureus in a mouse skin abscess model, suggesting that the active compound could potentially be used as a therapeutic agent for managing S. aureus infections.
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BACKGROUND: Atopic dermatitis (AD) is an inflammatory skin condition distinguished by an activated Th2 immune response. The local skin microbial dysbiosis is a contributing factor to the development of AD. The pathogenic coagulase-positive Staphylococcus aureus is the primary species responsible for the progression of AD. Even though Staphylococcus pseudintermedius is an animal-origin pathogen, it is increasingly becoming a source of concern in human diseases. As another coagulase-positive Staphylococci, it is crucial to pay more attention to S. pseudintermedius isolated from the lesion site. RESULTS: In our investigation, we presented a case of cheilitis in a patient with atopic dermatitis (AD). We utilized culture and next-generation genomic sequencing (NGS) to identify the bacteria present on the skin swabs taken from the lip sites both prior to and following treatment. Our findings indicated that the predominant bacteria colonizing the lesion site of AD were S. pseudintermedius and S. aureus, both of which were eradicated after treatment. The Multi-locus sequence typing (MLST) of S. pseudintermedius and S. aureus demonstrated coordinated antibiotic susceptibility, with ST2384 and ST22 being the respective types. Although the skin abscess area resulting from S. pseudintermedius infection was significantly smaller than that caused by S. aureus in mice, the expression of cytokines interleukin-4 (IL-4) and interleukin-5 (IL-5) were significantly higher in the S. pseudintermedius-infected mice. CONCLUSIONS: The S. pseudintermedius strain isolated from the lesion site of the AD patient exhibited a higher expression of IL-4 and IL-5 when colonized on mouse skin, as compared to S. aureus. This observation confirms that S. pseudintermedius can effectively induce the Th2 response in vivo. Our findings suggest that animal-origin S. pseudintermedius may play a role in the development of AD when colonized on the skin, emphasizing the importance of taking preventive measures when in contact with animals.
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Queilite , Coinfecção , Dermatite Atópica , Infecções Estafilocócicas , Humanos , Animais , Camundongos , Staphylococcus aureus/fisiologia , Dermatite Atópica/complicações , Dermatite Atópica/microbiologia , Interleucina-4 , Interleucina-5 , Tipagem de Sequências Multilocus , Queilite/complicações , Queilite/patologia , Coagulase , Infecções Estafilocócicas/complicações , Pele/microbiologiaRESUMO
Parental burnout refers to exhaustion caused by the parenting role. This devastating negative emotion can have repercussions for adolescent social development. Nevertheless, much remains unclear about the association between parental burnout and adolescent prosocial behavior and the potential mechanisms underlying this relationship. Based on theoretical and empirical evidence, the current study examined the relationship between parental burnout and adolescent prosocial behavior by using a sequential mediation model that included both parental empathy and adolescent empathy as potential mediators. A total of 488 parent-adolescent dyads (for adolescents: 45.7% men, 54.3% women, Mage = 15.28 ± 1.67 years; for parents: 36.5% fathers, 63.5% mothers, Mage = 41.30 ± 3.79 years) completed questionnaires regarding demographics, social desirability, parental burnout, parental empathy, adolescent empathy, and adolescent prosocial behavior. After controlling for demographic covariates and social desirability, the results showed that parental burnout had a negative effect on adolescent-reported prosocial behavior through parental cognitive empathy and adolescent other-oriented empathy (adolescent cognitive empathy and empathic concern) sequentially. These findings contribute to our understanding of the role of parental burnout as a family environmental factor detrimental to the positive functioning of adolescents through parental reactions to their children's emotions and children's own social competence.
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Because of their high energy density, low cost, and environmental friendliness, lithium-sulfur (Li-S) batteries are one of the potential candidates for the next-generation energy-storage devices. However, they have been troubled by sluggish reaction kinetics for the insoluble Li2S product and capacity degradation because of the severe shuttle effect of polysulfides. These problems have been overcome by introducing transition metal compounds (TMCs) as catalysts into the interlayer of modified separator or sulfur host. This review first introduces the mechanism of sulfur redox reactions. The methods for studying TMC catalysts in Li-S batteries are provided. Then, the recent advances of TMCs (such as metal oxides, metal sulfides, metal selenides, metal nitrides, metal phosphides, metal carbides, metal borides, and heterostructures) as catalysts and some helpful design and modulation strategies in Li-S batteries are highlighted and summarized. At last, future opportunities toward TMC catalysts in Li-S batteries are presented.
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Staphylococcus epidermidis (S. epidermidis), a human commensal, has been implicated in invasive infection in humans due to their ability to form biofilm. It is assumed that when a biofilm is dispersed it will subsequently cause a more severe infection. The clinical significance of S. epidermidis isolated from sterile body fluid (BF) remains unclear, and might be related to dispersal from catheter-associated biofilm infection. To evaluate this relationship, we evaluated S. epidermidis isolates from catheters (CA) or BF in hospitalized patients. Sequence type 2 (ST2) is the most prevalent type isolated from infection sites. Although the specific STs were also observed in isolates from different sites, we observed that the main sequence type was ST2, followed by ST59, among all the 114 isolates from different infection sites. Interestingly, ST2 strains isolated from BF exhibited significantly thicker biofilm than those from CA. The thicker biofilm was due to the higher expression of accumulation-associated protein (aap) but not intercellular adhesion (ica) operon. Moreover, the transcription of PSMδ and PSMε were significantly increased in ST2 strains isolated from BF. Although the bacterial loads on catheters were similar infected by CA- or BF-originated strains in mouse biofilm-associated infection model, we observed a higher CFU in peri-catheter tissues infected by ST2 clones isolated from BF, suggesting that S. epidermidis with thicker biofilm formation might be able to disperse. Taken together, our data suggested that S. epidermidis originated from diverse infection sites exhibited different biofilm forming capacity. The major ST2 clone isolated from BF exhibited thicker biofilm by increasing the expression of Aap. The higher expression of PSM of these strains may contribute to bacteria dispersal from biofilm and the following bacterial spread.
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Quasi-solid-state Zn-air batteries are usually limited to relatively low-rate ability (<10 mA cm-2), which is caused in part by sluggish oxygen electrocatalysis and unstable electrochemical interfaces. Here we present a high-rate and robust quasi-solid-state Zn-air battery enabled by atomically dispersed cobalt sites anchored on wrinkled nitrogen doped graphene as the air cathode and a polyacrylamide organohydrogel electrolyte with its hydrogen-bond network modified by the addition of dimethyl sulfoxide. This design enables a cycling current density of 100 mA cm-2 over 50 h at 25 °C. A low-temperature cycling stability of over 300 h (at 0.5 mA cm-2) with over 90% capacity retention at -60 °C and a broad temperature adaptability (-60 to 60 °C) are also demonstrated.
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Geopolymers may be the best alternative to ordinary Portland cement because they are manufactured using waste materials enriched in aluminosilicate. Research on geopolymer composites is accelerating. However, considerable work, expense, and time are needed to cast, cure, and test specimens. The application of computational methods to the stated objective is critical for speedy and cost-effective research. In this study, supervised machine learning approaches were employed to predict the compressive strength of geopolymer composites. One individual machine learning approach, decision tree, and two ensembled machine learning approaches, AdaBoost and random forest, were used. The coefficient correlation (R2), statistical tests, and k-fold analysis were used to determine the validity and comparison of all models. It was discovered that ensembled machine learning techniques outperformed individual machine learning techniques in forecasting the compressive strength of geopolymer composites. However, the outcomes of the individual machine learning model were also within the acceptable limit. R2 values of 0.90, 0.90, and 0.83 were obtained for AdaBoost, random forest, and decision models, respectively. The models' decreased error values, such as mean absolute error, mean absolute percentage error, and root-mean-square errors, further confirmed the ensembled machine learning techniques' increased precision. Machine learning approaches will aid the building industry by providing quick and cost-effective methods for evaluating material properties.
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Poultry litter waste is typically land-applied as a soil amendment but repeated application in the vicinity of poultry houses has led to phosphorus accumulation in soil. Such application can also lead to runoff that causes eutrophication. Most farmers store litter under dry conditions or compost the litter prior to land application, but it is not clear if these approaches are best from a nutrient management-perspective. The objective of this study was to investigate the effects of moisture content and active aeration on soluble mineral forms of nitrogen and phosphorus in poultry litter incubated for roughly one month. Mineral forms of nutrients are immediately plant-available upon field application and also most conducive to low-cost stripping and recovery methods. Litters were incubated at 50% and 70% moisture content with and without active aeration. Litter aeration led to significant ammonia losses and a consequent decline in litter pH but it had no effect on phosphate solubility. Moisture content during litter incubation governed the levels of plant-available phosphate and nitrification. High (70%) moisture led to 41%-78% higher plant-available phosphate (4.2-4.8 mg/g litter) compared to litters with 50% moisture content (2.7-3.0 mg/g litter). In contrast, the 50% moisture litters experienced 5-6 fold higher levels of nitrification (0.11-0.12 mg NO3-N/g litter) than litters with 70% moisture content (0.02 mg NO3-N/g litter), regardless of aeration. The implication is that lower-moisture litter storage is likely best for field application because phosphate is less soluble under neutral-alkaline conditions and therefore less likely to end up in runoff. In contrast, higher-moisture litter storage may be amenable to low-cost processes to leach and recover phosphate from litter.