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1.
Bioresour Technol ; 402: 130819, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38723728

RESUMO

This work investigated the effectiveness of free nitrous acid (FNA) in enhancing organic waste solubilization to improve biogas production in anaerobic digestion (AD). The results indicated that FNA pretreatment can enhance soluble organic content and control H2S odor in tested organic wastes, including food waste, sewage sludge, and their combination. However, a significant decrease (>50 %) in FNA concentration was found in the reactors, possibly due to denitrifier-driven NO2- consumption. Biochemical methane potential (BMP) tests showed a 25 ± 8 % enhancement in CH4 production in the reactors fed with mixed substrate pretreated with 2.9 mg FNA-N/L. However, the presence of NO2- (325.6-2368.0 mg N/L) in some BMP reactors, due to carryover from FNA pretreatment, adversely affected CH4 production (>55 %) and prolonged lag time (>4.2 times). These findings are valuable for researchers and practitioners in waste management, offering insights for implementing FNA pretreatment to enhance the biodegradability of organic wastes in AD.

2.
Int J Clin Pharm ; 2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-38407692

RESUMO

BACKGROUND: Several economic studies have assessed the cost-effectiveness of programmed cell death protein-1 (PD-1) inhibitors compared to second-line chemotherapy in treating esophageal squamous cell carcinoma (ESCC). However, there is a lack of economic comparisons among the different PD-1 inhibitors. AIM: This study aimed to assess the cost-effectiveness of PD-1 inhibitors (nivolumab, pembrolizumab, camrelizumab, and tislelizumab) in second-line treatment for advanced or metastatic ESCC within the Chinese healthcare system. METHOD: The clinical trials were systematically retrieved from PubMed, Embase, Web of Science, and the Cochrane Library. We established a fractional polynomials model to conduct a network meta-analysis, enabling the calculation of hazard ratios and expected survival rates. Economic outcomes were estimated using a partitioned survival model. The costs and utilities were gathered from published sources. The threshold for willingness-to-pay (WTP) for a quality-adjusted life year (QALY) was set at three times China's per capita gross domestic product in 2022. Sensitivity analyses (SA) were performed to address uncertainties in the model. RESULTS: Four phase III randomized controlled trials were included, evaluating the cost-effectiveness of four PD-1 inhibitors, camrelizumab, nivolumab, tislelizumab, and pembrolizumab, compared to chemotherapy for the second-line treatment of advanced or metastatic ESCC. For camrelizumab, nivolumab, tislelizumab, and pembrolizumab, the corresponding incremental cost-effectiveness ratios were $27,375.43/QALY, $205,312.19/QALY, $9,266.73/QALY, and $220,368.10/QALY, respectively. The SA results indicated the robustness of the base analysis findings. CONCLUSION: From the Chinese healthcare system, under the WTP of $38,253.48/QALY, tislelizumab is a cost-effective treatment option for the second-line treatment of advanced or metastatic ESCC.

3.
Proc Natl Acad Sci U S A ; 121(9): e2318181121, 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38346210

RESUMO

While it is commonly assumed that farmers have higher, and foragers lower, fertility compared to populations practicing other forms of subsistence, robust supportive evidence is lacking. We tested whether subsistence activities-incorporating market integration-are associated with fertility in 10,250 women from 27 small-scale societies and found considerable variation in fertility. This variation did not align with group-level subsistence typologies. Societies labeled as "farmers" did not have higher fertility than others, while "foragers" did not have lower fertility. However, at the individual level, we found strong evidence that fertility was positively associated with farming and moderate evidence of a negative relationship between foraging and fertility. Markers of market integration were strongly negatively correlated with fertility. Despite strong cross-cultural evidence, these relationships were not consistent in all populations, highlighting the importance of the socioecological context, which likely influences the diverse mechanisms driving the relationship between fertility and subsistence.


Assuntos
Economia , Fertilidade , Feminino , Humanos , Dinâmica Populacional , Fatores Socioeconômicos , Países em Desenvolvimento
4.
Environ Sci Technol ; 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38332486

RESUMO

Plastic debris, including nanoplastic particles (NPPs), has emerged as an important global environmental issue due to its detrimental effects on human health, ecosystems, and climate. Atmospheric processes play an important role in the transportation and fate of plastic particles in the environment. In this study, a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was employed to establish the first online approach for identification and quantification of airborne submicrometer polystyrene (PS) NPPs from laboratory-generated and ambient aerosols. The fragmentation ion C8H8+ is identified as the major tracer ion for PS nanoplastic particles, achieving an 1-h detection limit of 4.96 ng/m3. Ambient PS NPPs measured at an urban location in Texas are quantified to be 30 ± 20 ng/m3 by applying the AMS data with a constrained positive matrix factorization (PMF) method using the multilinear engine (ME-2). Careful analysis of ambient data reveals that atmospheric PS NPPs were enhanced as air mass passed through a waste incinerator plant, suggesting that incineration of waste may serve as a source of ambient NPPs. The online quantification of NPPs achieved through this study can significantly improve our understanding of the source, transport, fate, and climate effects of atmospheric NPPs to mitigate this emerging global environmental issue.

5.
Fish Shellfish Immunol ; 142: 109170, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37852511

RESUMO

Pseudomonas plecoglossicida infection is a highly contagious epidemic in aquaculture, causing significant mortality among teleost. Our previous research has demonstrated that Lactobacillus plantarum E2 is beneficial for large yellow croaker in resisting infections caused by P. plecoglossicida. However, the relevant mechanisms remain largely unclear. In the present study, we used zebrafish (Danio rerio) to further explore the function of L. plantarum E2 and its mechanisms for resisting P. plecoglossicida infection. E2 supplementation diet significantly improved the growth rates and α-amylase and trypsin activities of the liver in zebrafish. After challenge with P. plecoglossicida strain PQLYC4, the survival rates of zebrafish were improved, and immune-related genes expression (IL-1ß, TNF-α, IL-8, Ig-Z, TLR-22 and IL-12α) were down-regulated. Histological analysis showed that E2 group had a longer intestinal villus and thicker intestinal walls after 30 days of feeding and healthier intestinal structure after challenge with P. plecoglossicida strain PQLYC4. Furthermore, co-incubation of zebrafish embryo fibroblast (ZF-4 cells) with L. plantarum E2 reduced apoptosis of ZF-4 cells after exposed to P. plecoglossicida. Intestinal microbiota analysis showed that E2 strain significantly increased the relative abundance of Lactobacillus and Pseudomonas, and PCoA analysis revealed a noticeable divergence in the intestinal microbial communities after E2 supplement. Together, our results suggested that E2 strain may promote zebrafish survival against P. plecoglossicida infection by regulating the intestinal microbiota and alleviating inflammatory response and apoptosis, thus exhibiting the potential as a probiotic.


Assuntos
Microbioma Gastrointestinal , Lactobacillus plantarum , Infecções por Pseudomonas , Animais , Peixe-Zebra , Lactobacillus plantarum/química , Pseudomonas , Inflamação/veterinária , Infecções por Pseudomonas/prevenção & controle , Infecções por Pseudomonas/veterinária , Apoptose
6.
Evol Hum Sci ; 5: e4, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37587931

RESUMO

Increased access to defensible material wealth is hypothesised to escalate inequality. Market integration, which creates novel opportunities in cash economies, provides a means of testing this hypothesis. Using demographic data collected from 505 households among the matrilineal and patrilineal Mosuo in 2017, we test whether market integration is associated with increased material wealth, whether increased material wealth is associated with wealth inequality, and whether being in a matrilineal vs. patrilineal kinship system alters the relationship between wealth and inequality. We find evidence that market integration, measured as distance to the nearest source of tourism and primary source of household income, is associated with increased household income and 'modern' asset value. Both village-level market integration and mean asset value were associated negatively, rather than positively, with inequality, contrary to predictions. Finally, income, modern wealth and inequality were higher in matrilineal communities that were located closer to the centre of tourism and where tourism has long provided a relatively stable source of income. However, we also observed exacerbated inequality with increasing farm animal value in patriliny. We conclude that the forces affecting wealth and inequality depend on local context and that the importance of local institutions is obscured by aggregate statistics drawn from modern nation states.

7.
Nat Commun ; 14(1): 3843, 2023 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-37386013

RESUMO

Number sense, the ability to decipher quantity, forms the foundation for mathematical cognition. How number sense emerges with learning is, however, not known. Here we use a biologically-inspired neural architecture comprising cortical layers V1, V2, V3, and intraparietal sulcus (IPS) to investigate how neural representations change with numerosity training. Learning dramatically reorganized neuronal tuning properties at both the single unit and population levels, resulting in the emergence of sharply-tuned representations of numerosity in the IPS layer. Ablation analysis revealed that spontaneous number neurons observed prior to learning were not critical to formation of number representations post-learning. Crucially, multidimensional scaling of population responses revealed the emergence of absolute and relative magnitude representations of quantity, including mid-point anchoring. These learnt representations may underlie changes from logarithmic to cyclic and linear mental number lines that are characteristic of number sense development in humans. Our findings elucidate mechanisms by which learning builds novel representations supporting number sense.


Assuntos
Aprendizagem , Neurônios , Humanos , Cognição , Redes Neurais de Computação
8.
Philos Trans R Soc Lond B Biol Sci ; 378(1883): 20220299, 2023 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-37381853

RESUMO

Contemporary inequality exists at an unprecedented scale. Social scientists have emphasized the role played by material wealth in driving its escalation. Evolutionary anthropologists understand the drive to accumulate material wealth as one that is coupled ultimately to increasing reproductive success. Owing to biological caps on reproduction for women, the efficiency of this conversion can differ by gender, with implications for understanding the evolution of gender disparities in resource accumulation. Efficiency also differs according to the type of resources used to support reproductive success. In this paper, we review evolutionary explanations of gender disparities in resources and investigate empirical evidence to support or refute those explanations among matrilineal and patrilineal subpopulations of ethnic Chinese Mosuo, who share an ethnolinguistic identity, but differ strikingly in terms of institutions and norms surrounding kinship and gender. We find that gender differentially predicts income and educational attainment. Men were more likely to report income than women; amounts earned were higher for men overall, but the difference between men and women was minimal under matriliny. Men reported higher levels of educational attainment than women, unexpectedly more so in matrilineal contexts. The results reveal nuances in how biology and cultural institutions affect gender disparities in wealth. This article is part of the theme issue 'Evolutionary ecology of inequality'.


Assuntos
Povo Asiático , Sexismo , Feminino , Humanos , Masculino
10.
Clin Drug Investig ; 43(4): 251-263, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36943659

RESUMO

BACKGROUND AND OBJECTIVE: The efficacy and safety of iGlarLixi, a fixed-ratio combination (FRC) of basal insulin glargine plus lixisenatide, have been demonstrated in type 2 diabetes mellitus (T2DM) patients. However, no relevant economic analysis of iGlarLixi has been done in China. Thus, the primary objective of this study is to evaluate the cost effectiveness of iGlarLixi versus IDegAsp in Chinese T2DM patients, and then back-calculate the appropriate drug price of iGlarLixi to support its pricing after listing in China. METHODS: The United Kingdom Prospective Diabetes Study Outcome Model 2 (UKPDS OM2) was applied to estimate lifetime health and economic outcomes from the Chinese health-care system perspective. As no head-to-head comparison data are currently available, the baseline cohort characteristics and the initial clinical data for iGlarLixi were derived from the randomized LixiLan-L-China trial. The relative treatment effects for IDegAsp were based on an indirect treatment comparison. Due to the unavailability of iGlarLixi pricing data, the annual medication cost of iGlarLixi was assumed to be equal to that of IDegAsp at the beginning of the study. Afterwards, a break-even analysis using comparator drug price and the willingness-to-pay (WTP) threshold was performed to back-calculate the appropriate drug price of iGlarLixi. One-way sensitivity analysis, scenario analysis and probabilistic sensitivity analysis (PSA) were conducted to assess the robustness of the model. RESULTS: Based on the initial assumption of equal annual medication cost of iGlarLixi and IDegAsp, iGlarLixi was cost effective compared to IDegAsp with an incremental cost-effectiveness ratio (ICER) far below the WTP threshold in Chinese T2DM patients. From the back calculation for the price of iGlarLixi, the annual medication cost of iGlarLixi was $656.96 and $1075.96 to obtain an ICER of iGlarLixi versus IDegAsp close to 1 × GDP and 3 × GDP, respectively. When the discount rate was changed from the base value to 8% (the most sensitive parameter to the model results in one-way sensitivity analysis), the ICER was nearly equal to 1 × GDP and 3 × GDP with the annual medication cost of iGlarLixi decreasing to $590.41 and $865.03, respectively. Thus, iGlarLixi was dominant over IDegAsp with an annual medication cost of $590.41 to $865.03. The findings were robust to one-way sensitivity analysis, PSA and scenario analysis. CONCLUSION: This long-term cost-effectiveness analysis in Chinese T2DM patients indicates that iGlarLixi, assuming equal price to IDegAsp, is cost-effective versus IDegAsp with an ICER far below the WTP threshold. With 1 × GDP and 3 × GDP threshold set we back-calculate the appropriate annual medication cost of iGlarLixi to be $590.41 to $865.03, respectively.


Assuntos
Diabetes Mellitus Tipo 2 , Humanos , Glicemia , China , Análise de Custo-Efetividade , Diabetes Mellitus Tipo 2/tratamento farmacológico , Combinação de Medicamentos , Hemoglobinas Glicadas , Hipoglicemiantes/uso terapêutico , Insulina Glargina/uso terapêutico , Peptídeos , Estudos Prospectivos , Projetos Piloto
11.
JCI Insight ; 7(23)2022 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-36227697

RESUMO

Preeclampsia is a serious pregnancy disorder that lacks effective treatments other than delivery. Improper sensing of oxygen changes during placentation by prolyl hydroxylases (PHDs), specifically PHD2, causes placental hypoxia-inducible factor-1 (HIF1) buildup and abnormal downstream signaling in early-onset preeclampsia, yet therapeutic targeting of HIF1 has never been attempted. Here we generated a conditional (placenta-specific) knockout of Phd2 in mice (Phd2-/- cKO) to reproduce HIF1 excess and to assess anti-HIF therapy. Conditional deletion of Phd2 in the junctional zone during pregnancy increased placental HIF1 content, resulting in abnormal placentation, impaired remodeling of the uterine spiral arteries, and fetal growth restriction. Pregnant dams developed new-onset hypertension at midgestation (E9.5) in addition to proteinuria and renal and cardiac pathology, hallmarks of severe preeclampsia in humans. Daily injection of acriflavine, a small molecule inhibitor of HIF1, to pregnant Phd2-/- cKO mice from E7.5 (prior to hypertension) or E10.5 (after hypertension had been established) to E14.5 corrected placental dysmorphologies and improved fetal growth. Moreover, it reduced maternal blood pressure and reverted renal and myocardial pathology. Thus, therapeutic targeting of the HIF pathway may improve placental development and function, as well as maternal and fetal health, in preeclampsia.


Assuntos
Hipertensão , Prolil Hidroxilases , Gravidez , Humanos , Feminino , Camundongos , Animais , Acriflavina , Fator 1 Induzível por Hipóxia , Placenta , Hipertensão/tratamento farmacológico
12.
Front Microbiol ; 13: 922454, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35774453

RESUMO

A bacterium, Bacillus amyloliquefaciens W0101, isolated from the Arctic Ocean, showed potent antifungal activity against several plant pathogenic fungi. An antifungal peptide W1, with a molecular weight of approximately 2.4 kDa, was purified from the culture supernatant of the strain W0101 using ion-exchange chromatography and high-performance liquid chromatography. By analysis of Liquid Chromatograph-Mass Spectrometer, the peptide W1 was identified as a new antifungal peptide derived from the fragment of preprotein translocase subunit YajC. Further analysis revealed that W1 could disrupt the hyphae and spores of Sclerotinia sclerotiorum and inhibit its growth. W1 suppressed S. sclerotiorum and Fusarium oxysporum at a minimum inhibitory concentration of 140 and 58 µg/ml, respectively. The antifungal activity of W1 remained stable at 20-80°C or pH 6-11, with reduced activity at 100-110°C and pH 4-5, and under three protease treatments. Additionally, W1 also had a certain extent of metal ion resistance. These results therefore suggest that the peptide W1 from marine B. amyloliquefaciens W0101 may represent a new antifungal peptide with potential application in the biocontrol of plant diseases.

13.
Immunotherapy ; 14(11): 859-869, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35754404

RESUMO

Aim: To evaluate the cost-effectiveness of first-line treatment for advanced renal cell carcinoma with nivolumab plus cabozantinib versus sunitinib from a US payer perspective. Methods: Economic outcomes were estimated with Markov and partitioned survival models. Efficacy, safety and other data were taken from the CheckMate 9ER trial. Costs and utilities were gathered from published sources. Sensitivity analyses addressed model uncertainties. Results: The incremental cost-effectiveness ratio of nivolumab plus cabozantinib versus sunitinib was US$555,663 and $531,748 per quality-adjusted life year in the Markov and partitioned survival models, respectively, exceeding the willingness-to-pay threshold (US$150,000 per quality-adjusted life-year). Sensitivity analyses showed robust outcomes. Conclusion: From a US payer perspective, first-line nivolumab plus cabozantinib for advanced renal cell carcinoma is not cost effective.


Renal cell carcinoma (RCC) is a common cancer in the USA. Up to 30% of patients with RCC are in an advanced stage of disease at diagnosis. RCC is difficult to cure, with an 11% chance of survival after 5 years for patients with advanced RCC. A recent clinical study showed that nivolumab plus cabozantinib (NC) had a greater benefit in patients with advanced RCC than sunitinib. The US FDA approved NC for advanced RCC, but NC is relatively expensive. This study explored the cost­effectiveness of NC for advanced RCC versus sunitinib for a US payer using two cost­effectiveness models developed based on the results of the aforementioned clinical study. The results showed that to gain an additional year in perfect health, NC costs an average of US$555,663 or $531,748 more versus sunitinib, which is more than a US payer is willing to pay for an additional year in perfect health ($150,000). Therefore, NC for advanced RCC is not cost-effective versus sunitinib for a US payer at current prices.


Assuntos
Carcinoma de Células Renais , Neoplasias Renais , Anilidas , Análise Custo-Benefício , Humanos , Nivolumabe/uso terapêutico , Piridinas , Sunitinibe/uso terapêutico
14.
Cognition ; 224: 105067, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35219951

RESUMO

Most adults have access to two different number systems to represent numerical information: an exact number system, which relies on different forms of number symbols to represent exact numerical information, and an approximate number system, which allows for approximate estimates of numerical quantities. Here we investigate the integration between the symbolic and non-symbolic numerical information (i.e., "numerical integration"), and how numerical integration relates to adults' formal math abilities. We administered two tasks to measure numerical integration. For a number comparison task with non-symbolic dot arrays and Arabic numerals, participants indicated the larger of two sequentially presented stimuli that were same-format (dot-dot or numeral-numeral), or mixed-format (dot-numeral or numeral-dot). For a number-letter discrimination task, participants identified Arabic numerals or letter pairs that co-occurred with dot arrays (matching or mismatching the quantity represented by the numeral). In the number comparison task, participants were significantly slower when comparing mixed-format stimuli, especially when Arabic numerals were presented first and dot arrays second, suggesting estrangement between symbolic and non-symbolic numerical information and an asymmetry depending on the order in which the numerical information is presented. In contrast, in the number-letter discrimination task, participants were significantly faster in number-letter discrimination for matching dot arrays and numerals, suggesting integration between symbolic and non-symbolic numerical information. Surprisingly, some measures of numerical estrangement derived from the number comparison task significantly correlated with adults' performance on a standardized math assessment. Thus, we conclude that numerical integration or estrangement is task-dependent, and adults with greater levels of symbolic estrangement tend to have higher math skills.


Assuntos
Matemática , Adulto , Humanos
15.
Macromol Rapid Commun ; 43(4): e2100666, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34850490

RESUMO

Sequence plays a critical role in enabling unique properties and functions of natural biomolecules, which has promoted the rapid advancement of synthetic sequence-defined polymers in recent decades. Particularly, investigation of short chain sequence-defined oligomers (also called discrete oligomers) on their properties has become a hot topic. However, most studies have focused on discrete oligomers with conjugated structures. In contrast, unconjugated oligomers remain relatively underexplored. In this study, three pairs of discrete oligomers with the same composition but different sequence for each pair are employed for investigating their glass transition temperatures (Tg s). The resultant Tg s of sequenced oligomers in each pair are found to be significantly different (up to 11.6 °C), attributable to variations in molecular packing as demonstrated by molecular dynamics and density function theory simulations. Intermolecular interaction is demonstrated to have less impact on Tg s than intramolecular interaction. The mechanistic investigation into two model dimers suggests that monomer sequence caused the difference in intramolecular rotational flexibility of the sequenced oligomers. In addition, despite having different monomer sequence and Tg s, the oligomers have very similar solubility parameters, which supports their potential use as effective oligomeric plasticizers to tune the Tg s of bulk polymer materials.


Assuntos
Vidro , Simulação de Dinâmica Molecular , Polímeros/química , Temperatura , Temperatura de Transição
16.
Chem Commun (Camb) ; 57(82): 10759-10762, 2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34585689

RESUMO

Reversible addition-fragmentation chain transfer (RAFT) single unit monomer insertion (SUMI) of ß-methylstyrene derivatives into diverse RAFT agents presented fast reaction kinetics, but significant degradation of the SUMI products occurred due to a hydrogen abstraction reaction. Fortunately, such degradation can be suppressed through appropriate design of initial RAFT agents attributed to effective chain transfer and selective photoactivation.

17.
Nano Lett ; 21(5): 2191-2198, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33646790

RESUMO

Materials with interfaces often exhibit extraordinary phenomena exemplified by rich physics, such as high-temperature superconductivity and enhanced electronic correlations. However, demonstrations of confined interfaces to date have involved intensive effort and fortuity, and no simple path is consistently available. Here, we report the achievement of interfacial superconductivity in the nonsuperconducting parent compounds AEFe2As2, where AE = Ca, Sr, or Ba, by simple subsequent annealing of the as-grown samples in an atmosphere of As, P, or Sb. Our results indicate that the superconductivity originates from electron transfer at the interface of the hybrid van der Waals heterostructures, consistent with the two-dimensional superconducting transition observed. The observations suggest a common origin of interfaces for the nonbulk superconductivity previously reported in the AEFe2As2 compound family and provide insight for the further exploration of interfacial superconductivity.

18.
Artigo em Inglês | MEDLINE | ID: mdl-32224457

RESUMO

Existing enhancement methods are empirically expected to help the high-level end computer vision task: however, that is observed to not always be the case in practice. We focus on object or face detection in poor visibility enhancements caused by bad weathers (haze, rain) and low light conditions. To provide a more thorough examination and fair comparison, we introduce three benchmark sets collected in real-world hazy, rainy, and low-light conditions, respectively, with annotated objects/faces. We launched the UG2+ challenge Track 2 competition in IEEE CVPR 2019, aiming to evoke a comprehensive discussion and exploration about whether and how low-level vision techniques can benefit the high-level automatic visual recognition in various scenarios. To our best knowledge, this is the first and currently largest effort of its kind. Baseline results by cascading existing enhancement and detection models are reported, indicating the highly challenging nature of our new data as well as the large room for further technical innovations. Thanks to a large participation from the research community, we are able to analyze representative team solutions, striving to better identify the strengths and limitations of existing mindsets as well as the future directions.

19.
Brain Behav ; 8(4): e00938, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29670820

RESUMO

Introduction: Adults can represent numerical information in nonsymbolic and symbolic formats and flexibly switch between the two. While some studies suggest a strong link between the two number representation systems (e.g., Piazza, Izard, Pinel, Le Bihan, & Dehaene, 2004 Neuron, 44(3), 547), other studies show evidence against the strong-link hypothesis (e.g., Lyons, Ansari, & Beilock, 2012 Journal of Experimental Psychology: General, 141(4), 635). This inconsistency could arise from the relation between task demands and the closeness of the link between the two number systems. Methods: We used a passive viewing task and event-related potentials (ERP) to examine the temporal dynamics of the implicit integration between the nonsymbolic and symbolic systems. We focused on two ERP components over posterior scalp sites that were found to be sensitive to numerical distances and ratio differences in both numerical formats: a negative component that peaks around 170 ms poststimulus (N1) and a positive component that peaks around 200 ms poststimulus (P2p). We examined adults' (n = 55) ERPs when they were passively viewing simultaneously presented dot quantities and Arabic numerals (i.e., nonsymbolic and symbolic numerical information) in the double-digit range. For each stimulus, the nonsymbolic and symbolic content either matched or mismatched in number. We also asked each participant to estimate dot quantities in a separate behavioral task and observed that they tended to underestimate the actual dot quantities, suggesting a need to adjust the match between nonsymbolic and symbolic information to reflect the perceived quantity of the nonsymbolic information. Results: Using this adjustment, participants showed greater N1 and P2p amplitudes when perceived dot quantities matched Arabic numerals than when there was a mismatch. However, no differences were found between the unadjusted match and mismatch conditions. Conclusion: Our findings suggest that adults rapidly integrate nonsymbolic and symbolic formats of double-digit numbers, but evidence of such integration is best observed when the perceived (rather than veridical) dot quantity is considered.


Assuntos
Encéfalo/fisiologia , Eletroencefalografia/métodos , Matemática , Adulto , Potenciais Evocados , Feminino , Humanos , Masculino , Análise e Desempenho de Tarefas , Adulto Jovem
20.
J Colloid Interface Sci ; 521: 242-251, 2018 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-29574343

RESUMO

Conjugating nanoparticles with polyethylene glycol (PEG) is a useful strategy to improve the colloidal and biological stability of nanoparticles. However, studies on PEGylation of two-dimensional layered double hydroxide (LDH) nanoparticles are very limited. The present work reported two functionalization approaches to synthesize PEG-conjugated LDH nanoparticles by introducing phosphonic acid terminated PEG before and after LDH aging. The successful PEGylation was confirmed and suggested to be via electrostatic interaction and a ligand exchange process. Different functionalization approaches resulted in different binding types of PEG on/in LDH nanoparticles. The PEG coating maintained the dispersity of LDH nanoparticles in water and saline with the feeding mass ratio of 1:1. Further colloidal stability tests of PEGylated LDHs revealed that the PEGylated LDH dispersity was affected by the feeding mass ratio of PEG/LDH, the molar weight of PEG and anions intercalated in the LDHs. In a test to determine the extent of non-specific protein adsorption, the PEGylation was effective at resisting non-specific bovine serum albumin adsorption on LDH nanoparticles with both functionalization methods investigated. Moreover, PEGylated LDH nanoparticles had no effect on cell viability up to 500 µg/mL, and demonstrated enhanced cellular uptake in a SK-MEL-28 cell culture. The results in this work indicate that conjugating phosphonic acid-terminated PEG on LDH nanoparticles is a promising strategy to improve the colloidal and biological stability of LDHs for biomedical applications.


Assuntos
Portadores de Fármacos/química , Hidróxidos/química , Nanopartículas/química , Ácidos Fosforosos/química , Polietilenoglicóis/química , Adsorção , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Coloides , Portadores de Fármacos/toxicidade , Excipientes/química , Fluoresceína-5-Isotiocianato/química , Corantes Fluorescentes/química , Humanos , Nanopartículas/toxicidade , Tamanho da Partícula , Soroalbumina Bovina/química , Solubilidade , Propriedades de Superfície , Água
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