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One of the great challenges in the use of nanomaterials is their production at low costs and high yields. In this work aluminum nanoparticles, from aluminum powder, were produced by wet mechanical milling through a combination of different attrition milling conditions such as ball-powder ratio (BPR) and the amount of solvent used. It was observed that at 600 rpm with a BPR of 500/30 g for 12 h, it was possible to produce nanoparticles with a size close to 20 nm, while at 750 rpm with a BPR of 380/12.6 g for 12 h, nanoparticles of approximately 10 nm were obtained. Scanning and transmission electron microscopy confirmed that the milling product is an agglomeration of nanoparticles with different sizes. These results show the feasibility of obtaining aluminum nanoparticles by mechanical milling using only ethanol as solvent, avoiding hazardous by-products obtained from chemical routes, and the use of complicated methods such as laser ablation and arc discharge.
To investigate if depression risk modifies the association between frailty and mortality in older adults.
Ongoing cohort study.
Albacete city, Spain
Eight hundred subjects, 58.8% women, over 70 years of age from the Frailty and Dependence in Albacete (FRADEA) study.
Frailty phenotype, Geriatric Depression Scale (GDS), comorbidity, disability, and drug use were collected at baseline. Six groups were categorized: (G1: non-frail/no depression risk; G2: non-frail/depression risk; G3: prefrail/no depression risk; G4: prefrail/depression risk; G5: frail/no depression risk; and G6: frail/depression risk). Mean follow-up was 2542 days (SD 1006). GDS was also analyzed as a continuous variable. The association between frailty and depression risk with 10-year mortality was analyzed.
Mean age was 78.5 years. Non-frail was 24.5%, prefrail 56.3%, frail 19.3%, and 33.5% at depression risk. Mean GDS score was 3.7 (SD 3.2), increasing with the number of frailty criteria (p < 0.001). Ten-year mortality rate was 44.9%. Mortality was 21.4% for the non-frail, 45.6% for the prefrail, and 72.7% for the frail participants, 56% for those with depression risk, and 39.3% for those without depression risk. Mean survival times for groups G1 to G6 were, respectively, 3390, 3437, 2897, 2554, 1887, and 1931 days. Adjusted mortality risk was higher for groups G3 (HR 2.1; 95% confidence interval (CI) 1.4–3.1), G4 (HR 2.5; 95% CI 1.7–3.8), G5 (HR 3.8; 95% CI 2.4–6.1), and G6 (HR 4.0; 95% CI 2.6–6.2), compared with G1 (p < 0.001). Interaction was found between frailty and depression risk, although they were independently associated with mortality.
Depression risk increases mortality risk in prefrail older adults but not in non-frail and frail ones. Depression should be monitored in these older adults to optimize health outcomes. Factors modulating the relationship between frailty and depression should be explored in future studies.
The COVID-19 pandemic has created an unprecedented global crisis, necessitating drastic changes to living conditions, social life, personal freedom and economic activity. No study has yet examined the presence of psychiatric symptoms in the UK population under similar conditions.
We investigated the prevalence of COVID-19-related anxiety, generalised anxiety, depression and trauma symptoms in the UK population during an early phase of the pandemic, and estimated associations with variables likely to influence these symptoms.
Between 23 and 28 March 2020, a quota sample of 2025 UK adults aged 18 years and older, stratified by age, gender and household income, was recruited by online survey company Qualtrics. Participants completed standardised measures of depression, generalised anxiety and trauma symptoms relating to the pandemic. Bivariate and multivariate associations were calculated for demographic and health-related variables.
Higher levels of anxiety, depression and trauma symptoms were reported compared with previous population studies, but not dramatically so. Anxiety or depression and trauma symptoms were predicted by young age, presence of children in the home, and high estimates of personal risk. Anxiety and depression were also predicted by low income, loss of income and pre-existing health conditions in self and others. Specific anxiety about COVID-19 was greater in older participants.
This study showed a modest increase in the prevalence of mental health problems in the early stages of the pandemic, and these problems were predicted by several specific COVID-related variables. Further similar surveys, particularly of those with children at home, are required as the pandemic progresses.
Subjects with bipolar disorder (BD) show heterogeneous cognitive profile and that not necessarily the disease will lead to unfavorable clinical outcomes. We aimed to identify clinical markers of severity among cognitive clusters in individuals with BD through data-driven methods.
We recruited 167 outpatients with BD and 100 unaffected volunteers from Brazil and Spain that underwent a neuropsychological assessment. Cognitive functions assessed were inhibitory control, processing speed, cognitive flexibility, verbal fluency, working memory, short- and long-term verbal memory. We performed hierarchical cluster analysis and discriminant function analysis to determine and confirm cognitive clusters, respectively. Then, we used classification and regression tree (CART) algorithm to determine clinical and sociodemographic variables of the previously defined cognitive clusters.
We identified three neuropsychological subgroups in individuals with BD: intact (35.3%), selectively impaired (34.7%), and severely impaired individuals (29.9%). The most important predictors of cognitive subgroups were years of education, the number of hospitalizations, and age, respectively. The model with CART algorithm showed sensitivity 45.8%, specificity 78.4%, balanced accuracy 62.1%, and the area under the ROC curve was 0.61. Of 10 attributes included in the model, only three variables were able to separate cognitive clusters in BD individuals: years of education, number of hospitalizations, and age.
These results corroborate with recent findings of neuropsychological heterogeneity in BD, and suggest an overlapping between premorbid and morbid aspects that influence distinct cognitive courses of the disease.
Patients with schizophrenia spectrum disorders (SSD) tend to lack insight, which is linked to poor outcomes. The effect size of previous treatments on insight changes in SSD has been small. Metacognitive interventions may improve insight in SSD, although this remains unproved.
We carried out a systematic review and meta-analysis of randomized controlled trials (RCTs) to examine the effects of metacognitive interventions designed for SSD, namely Metacognitive Training (MCT) and Metacognitive Reflection and Insight Therapy (MERIT), on changes in cognitive and clinical insight at post-treatment and at follow-up.
Twelve RCTs, including 10 MCT RCTs (n = 717 participants) and two MERIT trials (n = 90), were selected, totalling N = 807 participants. Regarding cognitive insight six RCTs (n = 443) highlighted a medium effect of MCT on self-reflectiveness at post-treatment, d = 0.46, p < 0.01, and at follow-up, d = 0.30, p < 0.01. There was a small effect of MCT on self-certainty at post-treatment, d = −0.23, p = 0.03, but not at follow-up. MCT was superior to controls on an overall Composite Index of cognitive insight at post-treatment, d = 1.11, p < 0.01, and at follow-up, d = 0.86, p = 0.03, although we found evidence of heterogeneity. Of five MCT trials on clinical insight (n = 244 participants), which could not be meta-analysed, four of them favoured MCT compared v. control. The two MERIT trials reported conflicting results.
Metacognitive interventions, particularly Metacognitive Training, appear to improve insight in patients with SSD, especially cognitive insight shortly after treatment. Further long-term RCTs are needed to establish whether these metacognitive interventions-related insight changes are sustained over a longer time period and result in better outcomes.
In 2014, Baumslag and Wiegold proved that a finite group G is nilpotent if and only if o(xy) = o(x)o(y) for every x, y ∈ G with (o(x), o(y)) = 1. This has led to a number of results that characterize the nilpotence of a group (or the existence of nilpotent Hall subgroups, or the existence of normal Hall subgroups) in terms of prime divisors of element orders. Here, we look at these results with a new twist. The first of our main results asserts that G is nilpotent if and only if o(xy) ⩽ o(x)o(y) for every x, y ∈ G of prime power order with (o(x), o(y)) = 1. As an immediate consequence, we recover the Baumslag–Wiegold theorem. The proof of this result is elementary. We prove some variations of this result that depend on the classification of finite simple groups.
In an interesting paper, Fong (2020) raises objections to my approach to English modals (and modality in general) which he views as too general and not fully compliant with the postulates of Construction Grammar. In this response paper, I intend to explain in some depth the benefits of my approach, as well as the reasons why Construction Grammar, in particular Cognitive Construction Grammar (Goldberg, 1995, 2006, 2019), needs to be interrogated and adapted as a conceptual framework to explain language learning and processing.
Herein, we report a methodology that leads to the formation of Ru metallic sites, followed by the development and anchorage of Pt-Ru alloyed nanoparticles on the surface of Ordered Mesoporous Hollow Carbon Spheres (OMHCS). Along with the Ru sites, it is demonstrated that the functionalization promotes the formation of functional groups on the surface of the OMHCS. In a first stage, OMHCS are functionalized with the [(η6-C6H5OCH2CH2OH)RuCl2]2 (Ru-dim) and [(η6-C6H4CH(CH3)2CH3)RuCl2]2 (Ru-cym) organometallic compounds. Afterwards, Pt nanoparticles are dispersed by the microwave-assisted polyol method over the functionalized supports obtaining the low-metal content 5 wt. % Pt/OMHCSRu-dim and Pt/OMHCSRu-cym nanocatalysts. The degree of Ru alloyed is found to be around 35%. The low-Pt content Pt/OMHCSRu-cym and Pt/OMHCSRu-dim exhibit a higher catalytic activity for the Oxygen (OER) and the Hydrogen (HER) Evolution Reactions than the Pt/C benchmark and the Pt/OMHCS nanocatalysts. The overpotential for the OER at 10 mA cm-2 (ηOER) is 300 mV and 210 mV smaller at Pt/OMHCSRu-cym and Pt/OMHCSRu-dim compared to Pt/C, respectively. The corresponding values of the HER at -10 mA cm-2 (ηHER) are 14 and 18 mV smaller, respectively. The high catalytic activity of Pt/OMHCSRu-cym and Pt/OMHCSRu-dim has been attributed in part to the presence of Ru0 and RuO2 species from organometallic functionalization, and the modification of the d-valence band of Pt. Their high performance for the OER and the HER opens new lines of research for the design of nanocatalysts for alkaline electrochemical water splitting.
In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).
The global growing rates of cognitive decline and dementia, together with the absence of curative therapies for these conditions, support the interest in researching potential primary prevention interventions, with particular focus on dietary habits. The aim was to assess the association between the intake of polyphenols and 6-year change in cognitive function in the “Seguimiento Universidad de Navarra” (SUN) Project, a Spanish prospective cohort study. Changes (final – initial) in cognitive function were evaluated in a subsample of 806 participants (mean age 66 years (SD 5), 69.7% male) of the SUN Project using the validated Spanish Telephone Interview for Cognitive Status-modified (STICS-m) score. Polyphenol intake was derived from a validated semi-quantitative food-frequency questionnaire and matching food composition data from the Phenol Explorer database. Multivariable linear regression models were used to evaluate the association between total polyphenol intake, polyphenol subclasses and cognitive changes. No significant association between total polyphenol intake and changes in cognitive function was found. However, a higher intake of lignans (βQuintile (Q) 5 vs. Q1 0.81; 95% CI 0.12, 1.51; p trend = 0.020) and stilbenes (βQ5 vs. Q1 0.82; 95% CI 0.15, 1.49; p trend 0.028) was associated with more favorable changes in cognitive function over time, particularly with respect to immediate memory and language domains. Olive oil and nuts were the major sources of variability in lignan intake; and wine in stilbene intake. The results suggest that lignan and stilbene intake was associated with improvements in cognitive function.
We investigate the late-time Richtmyer–Meshkov instability (RMI) growth of sinuous perturbations on an air/sulphur hexafluoride interface (Atwood number,
$A \sim 0.67$
) subjected to a Mach 1.2 planar shock wave at Los Alamos National Laboratory's vertical shock tube facility. Interface perturbations are established using a novel membraneless technique where cross-flowing air and SF
separated by an oscillating splitter plate create a perturbed density interface. The interface formed has multi-modal features and residual small perturbations, however, a dominant mode is still noticeable. The late-time perturbation growths scale with
initial conditions (where
is the wavenumber and
is the initial amplitude of the dominant mode) as measured at the pre-shock interface. Past nonlinear models based on potential-flow theory, heuristic/interpolation approaches, Padé approximants and numerical simulations are evaluated against present experimental results. Accounting for an explicit
dependence in Sadot et al.'s (Phys. Rev. Lett., vol. 80, issue 8, 1998, pp. 1654–1657) model, we propose an empirical rational function that captures the asymptotic behaviour of perturbation growth for a broad range of initial conditions (
$0.30 \leq ka_0 \leq 0.86$
). The onset of mixing transition and its initial condition dependence are investigated with respect to the minimum state criterion (
$Re = 1.6 \times 10^5$
) for unsteady flows by Zhou (Phys. Plasmas, vol. 14, 2007, 082701). Earlier mixing transitions for higher
initial conditions are noted from local and global Reynolds number estimates which are corroborated by the existence of an inertial sub-range and formation of mixing regions indicating the physical significance of the minimum state criterion in RMI flows. The transition is accompanied by the increasing teapot-like appearance of joint probability density functions of
(invariants of the reduced velocity gradient tensor), establishing the technique as a useful tool for turbulence detection in two-dimensional diagnostics.
Acute respiratory infection is one of the main causes of morbidity in children. Some studies have suggested that pulmonary hypertension and congenital heart disease with haemodynamic repercussion increase the severity of respiratory infections, but there are few publications in developing countries.
This was a prospective cohort study evaluating the impact of pulmonary hypertension and congenital heart disease (CHD) with haemodynamic repercussion as predictors of severity in children under 5 years of age hospitalised for acute respiratory infection.
Altogether, 217 children hospitalised for a respiratory infection who underwent an echocardiogram were evaluated; 62 children were diagnosed with CHD with haemodynamic repercussion or pulmonary hypertension. Independent predictors of admission to intensive care included: pulmonary hypertension (RR 2.14; 95% CI 1.06–4.35, p = 0.034), respiratory syncytial virus (RR 2.52; 95% CI 1.29–4.92, p = 0.006), and bacterial pneumonia (RR 3.09; 95% CI 1.65–5.81, p = 0.000). A significant difference was found in average length of hospital stay in children with the cardiovascular conditions studied (p = 0.000).
Pulmonary hypertension and CHD with haemodynamic repercussion as well as respiratory syncytial virus and bacterial pneumonia were predictors of severity in children with respiratory infections in this study. Early recognition of cardiovascular risks in paediatric populations is necessary to lessen the impact on respiratory infections.
Prior theory and research has implicated disgust as relevant to some, but not all phobias.
The current study examined whether anxiety sensitivity is more relevant to certain specific phobias and whether disgust sensitivity is more relevant to other specific phobias.
Participants (n = 201) completed measures of anxiety sensitivity, disgust sensitivity and measures of aversive reactions in the presence of two fear-relevant stimuli (i.e. heights and small, enclosed spaces) and two disgust-relevant stimuli (i.e. spiders and blood/injury).
Results of multiple linear regression analyses revealed that disgust sensitivity showed significant associations with aversive reactions in all four stimulus domains after controlling for anxiety sensitivity. After controlling for disgust sensitivity, anxiety sensitivity showed associations with the two fear-relevant phobias but not with the two disgust-relevant phobias included in this study. Anxiety sensitivity also showed an association with variance specific to one of the two fear-relevant specific phobias included in the study. Disgust sensitivity also showed associations with variance specific to both of the disgust-relevant phobias included in the study but not with variance specific to either of the fear-relevant specific phobias.
These results provide evidence that the distinction between fear-relevant and disgust-relevant specific phobias is meaningful and also implicate disgust sensitivity as relevant to aversive reactions to all stimuli included in this study.
The coronavirus disease 2019 (COVID-19) pandemic has induced a reinforcement of infection control measures in the hospital setting. Here, we assess the impact of the COVID-19 pandemic on the incidence of nosocomial Clostridioides difficile infection (CDI).
We retrospectively compared the incidence density (cases per 10,000 patient days) of healthcare-facility–associated (HCFA) CDI in a tertiary-care hospital in Madrid, Spain, during the maximum incidence of COVID-19 (March 11 to May 11, 2020) with the same period of the previous year (control period). We also assessed the aggregate in-hospital antibiotic use (ie, defined daily doses [DDD] per 100 occupied bed days [BD]) and incidence density (ie, movements per 1,000 patient days) of patient mobility during both periods.
In total, 2,337 patients with reverse transcription-polymerase chain reaction–confirmed COVID-19 were admitted to the hospital during the COVID-19 period. Also, 12 HCFA CDI cases were reported at this time (incidence density, 2.68 per 10,000 patient days), whereas 34 HCFA CDI cases were identified during the control period (incidence density, 8.54 per 10,000 patient days) (P = .000257). Antibiotic consumption was slightly higher during the COVID-19 period (89.73 DDD per 100 BD) than during the control period (79.16 DDD per 100 BD). The incidence density of patient movements was 587.61 per 1,000 patient days during the control period and was significantly lower during the COVID-19 period (300.86 per 1,000 patient days) (P < .0001).
The observed reduction of ~70% in the incidence density of HCFA CDI in a context of no reduction in antibiotic use supports the importance of reducing nosocomial transmission by healthcare workers and asymptomatic colonized patients, reinforcing cleaning procedures and reducing patient mobility in the epidemiological control of CDI.
This paper contributes to the literature on the determinants of environmental standards by studying the role of income inequality and freedom of the press. Given that evidence of the environmental Kuznets curve has only been found for some countries, it is thus crucial to investigate whether other factors besides income per capita levels may be affecting countries' decisions to pass environmentally-friendly legislation. We investigate the effects that inequality and freedom of the press have on environmental stringency for a sample of OECD and BRIICS countries and a global sample of 82 countries using data over the period 1994–2015. We hypothesize that the more unequal a society is, and the greater the oppression of the press is, the less stringent environmental policies are. The results partially confirm our hypothesis. In particular, lack of press freedom is negatively correlated with environmental stringency, whereas inequality shows a non-linear effect only for non-high-income countries.
Globally, rock art is one of the most widely distributed manifestations of past human activity. Previous research, however, has tended to focus on the art rather than artists. Understanding which members of society participated in creating such art is crucial to interpreting its social implications and that of the sites at which it is found. This article presents the first application of a method—palaeodermatoglyphics—for the estimation of the sex and age of two later prehistoric individuals who left their fingerprints at the Los Machos rockshelter in southern Iberia. The method has the potential to illuminate the complex socio-cultural dimensions of rock art sites worldwide.
The Mayan Codex of Mexico (MCM), the only Mayan codex found in the 20th century, was unveiled in 1971 during the Ancient Maya Calligraphy exhibition at Club Grolier. The codex comprises 10 pages of bark paper in accordion format, coated with a layer of plaster on both sides. It illustrates the synodic cycles of Venus, with its four phases. Since its discovery, the MCM has been subject to controversy and discussions about its authenticity. In 2016, a group of specialists led by Baltazar Brito chief of the National Library of Anthropology and History, carried out an exhaustive study of the codex with the purpose of determining its temporality and authenticity. In this work, the pre-Columbian authenticity of the codex is verified by the radiocarbon (14C) technique using AMS. Two cleaning procedures were contrasted: the standard acid-base-acid (ABA) protocol and a second one with Soxhlet plus ABA. Results obtained when samples were prepared following ABA protocol only, placed the age of the bark paper between 991 and 1147 cal AD. The second cleaning method with Soxhlet plus ABA, resulted in younger ages, between 1159 and 1261 cal AD. However, we consider that when Sohxlet is used as part of the cleaning protocol, organic contaminants are reduced to a minimum, and 14C dates are more reliable. These results indicate that the vegetal support of the MCM belongs to Postclassical Mayan period and place it as the oldest known manuscript of America found to date.