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"Abreu, M"
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Thermal features of Barrow corrected-entropy black hole formulation
Through the last years, it was demonstrated that quantum corrections of entropy, represented by logarithmic and power law corrections terms, constituted an association between semi-classical entropic areas and the curvature correction in Einstein–Hilbert’s Lagrangian and vice-versa. Loop quantum gravity approach provided the logarithmic corrections, which arises from quantum and thermal equilibrium fluctuations. On the other hand, Barrow’s entropy was introduced from the fact that the black hole surface can be modified due to quantum gravitational effects. The new exponent
Δ
that appears in Barrow’s entropy is a measure of this perturbation. In this letter we have analyzed the thermodynamical effects of the quantum fluctuations upon the geometry of a Barrow’s black hole. We demonstrated that new formulations of the equipartition law, which corresponds to the horizon energy, can be constructed from both entropic formalisms. Besides, we have calculated the heat capacity for both formulations and we discussed their thermal viability. We have also establish a condition on one of the constant pre-factors of the logarithmic correction.
Journal Article
Bilingualism Enriches the Poor: Enhanced Cognitive Control in Low-Income Minority Children
This study explores whether the cognitive advantage associated with bilingualism in executive functioning extends to young immigrant children challenged by poverty and, if it does, which specific processes are most affected. In the study reported here, 40 Portuguese-Luxembourgish bilingual children from low-income immigrant families in Luxembourg and 40 matched monolingual children from Portugal completed visuospatial tests of working memory, abstract reasoning, selective attention, and interference suppression. Two broad cognitive factors of executive functioning—representation (abstract reasoning and working memory) and control (selective attention and interference suppression)—emerged from principal component analysis. Whereas there were no group differences in representation, the bilinguals performed significantly better than did the monolinguals in control. These results demonstrate, first, that the bilingual advantage is neither confounded with nor limited by socioeconomic and cultural factors and, second, that separable aspects of executive functioning are differentially affected by bilingualism. The bilingual advantage lies in control but not in visuospatial representational processes.
Journal Article
Delayed childhood neurodevelopment and neurosensory alterations in the second year of life in a prospective cohort of ZIKV-exposed children
We report neurodevelopmental outcomes in 216 infants followed since the time of PCR-confirmed maternal Zika virus (ZIKV) infection in pregnancy during the Rio de Janeiro epidemic of 2015–2016 (refs.
1
,
2
). Neurodevelopment was assessed by Bayley Scales of Infant and Toddler Development, third edition (Bayley-III; cognitive, language and motor domains) in 146 children and through neurodevelopment questionnaires/neurological examinations in 70 remaining children. Complete eye exams (
n
= 137) and hearing assessments (
n
= 114) were also performed. Below-average neurodevelopment and/or abnormal eye or hearing assessments were noted in 31.5% of children between 7 and 32 months of age. Among children assessed by Bayley-III, 12% scored below –2 s.d. (score <70; a score of 100 ± 2 s.d. is the range) in at least one domain; and 28% scored between −1 and −2 s.d. in any domain (scores <85–70). Language function was most affected, with 35% of 146 children below average. Improved neurodevelopmental outcomes were noted in female children, term babies, children with normal eye exams and maternal infection later in pregnancy (
P
= 0.01). We noted resolution of microcephaly with normal neurodevelopment in two of eight children, development of secondary microcephaly in two other children and autism spectrum disorder in three previously healthy children in the second year of life.
Nearly one-third of infants born to mothers with confirmed Zika virus (ZIKV) infection during pregnancy have developmental impairments that can be delayed in their presentation, warranting long-term monitoring of ZIKV-exposed children.
Journal Article
From cold to hot: mechanisms of hyperthermia in modulating tumor immunology for enhanced immunotherapy
The emergence of immunotherapies has revolutionized cancer treatment by leveraging the immune system to target malignancies, offering new hope where traditional therapies often fall short. Within this context, hyperthermia (HT) has re-emerged as a promising adjunctive treatment, capable of enhancing the effectiveness of radiotherapy, chemotherapy, and immunotherapy. HT influences both the innate and adaptive immune systems, enhancing the activity of immune cells such as neutrophils, NK cells, and dendritic cells, while also modulating the tumor microenvironment (TME) to promote immunogenic cell death (ICD) and reduce immunosuppressive conditions. These effects contribute to the transformation of immunologically “cold” tumors into “hot” tumors, making them more susceptible to immune-mediated destruction. Furthermore, HT can amplify the efficacy of immune checkpoint inhibitors (ICIs) by improving immune cell infiltration, inducing damage-associated molecular pattern (DAMP) release, and enhancing antigen presentation. Preclinical and clinical studies support the combination of HT with ICIs, demonstrating improved outcomes in otherwise resistant tumors. However, the full therapeutic potential of the different technologies allowing to apply HT remains to be fully understood, and further research is needed to optimize treatment protocols, explore the differential impacts of local versus whole-body hyperthermia, and identify biomarkers for patient stratification. This review underscores the multifaceted role of HT in immunity and its potential to significantly enhance the efficacy of immunotherapy.
Journal Article
Unexpectedly high leprosy seroprevalence detected using a random surveillance strategy in midwestern Brazil: A comparison of ELISA and a rapid diagnostic test
Leprosy diagnosis is mainly based on clinical evaluation, although this approach is difficult, especially for untrained physicians. We conducted a temporary campaign to detect previously unknown leprosy cases in midwestern Brazil and to compare the performance of different serological tests.
A mobile clinic was stationed at the main bus terminal in Brasília, Brazil. Volunteers were quizzed and given a clinical exam to allow categorization as either patients, known contacts of patients or non-contacts, and blood was collected to determine anti-PGL-I and anti-LID-1 antibody titers by ELISA and by the NDO-LID rapid test. New cases of leprosy and the impact of performing this broad random surveillance strategy were evaluated. Accuracy values and concordance between the test results were evaluated among all groups.
Four hundred thirty-four individuals were evaluated, and 44 (10.1%) were diagnosed with leprosy. Borderline forms were the most frequent presentation. Both tests presented higher positivity in those individuals with multibacillary disease. Serological tests demonstrated specificities arround 70% for anti-PGL-1 and anti-LID ELISA; and arround 40% for NDO-LID. Sensitivities ranged from 48 to 62%. A substantial agreement between NDO-LID and ELISA with concomitant positive results was found within leprosy patients (Kappa index = 0.79 CI95% 0.36-1.22).
The unexpectedly high leprosy prevalence in this population indicates ongoing community-based exposure to Mycobacterium leprae antigens and high rates of subclinical infection. All tests showed low specificity and sensitivity values and therefore cannot be considered for use as stand-alone diagnostics. Rather, considering their positivity among MB patients and non-patients, these tests can be considered effective tools for screening and identifying individuals at high risk who might benefit from regular monitoring.
Journal Article
Fluid dynamics in the warp drive spacetime geometry
The Alcubierre warp drive metric is a spacetime geometry featuring a spacetime distortion, called a warp bubble, where a massive particle inside it acquires global superluminal velocities, or warp speeds. This work presents solutions of the Einstein equations for the Alcubierre metric having fluid matter as gravity source. The energy–momentum tensor considered has two fluid contents, the perfect fluid and the parametrized perfect fluid (PPF), a tentative more flexible model whose aim is to explore the possibilities of warp drive solutions with positive matter density content. Santos-Pereira et al. (Eur Phys J C 80:786, 2020) already showed that the Alcubierre metric having dust as source connects this geometry to the Burgers equation, which describes shock waves moving through an inviscid fluid, but led the solutions back to vacuum. The same happened for two out of four solutions subcases for the perfect fluid. Other solutions for the perfect fluid indicate the possibility of warp drive with positive matter density, but at the cost of a complex solution for the warp drive regulating function. Regarding the PPF, solutions were also obtained indicating that warp speeds could be created with positive matter density. Weak, dominant, strong and null energy conditions were calculated for all studied subcases, being satisfied for the perfect fluid and creating constraints in the PPF quantities such that a positive matter density is also possible for creating a warp bubble. Summing up all results, energy–momentum tensors describing more complex forms of matter or field distributions generate solutions for the Einstein equations with the warp drive metric where a negative matter density might not be a strict precondition for attaining warp speeds.
Journal Article
Inhibition of GPX4 enhances CDK4/6 inhibitor and endocrine therapy activity in breast cancer
CDK4/6 inhibition in combination with endocrine therapy is the standard of care for estrogen receptor (ER+) breast cancer, and although cytostasis is frequently observed, new treatment strategies that enhance efficacy are required. Here, we perform two independent genome-wide CRISPR screens to identify genetic determinants of CDK4/6 and endocrine therapy sensitivity. Genes involved in oxidative stress and ferroptosis modulate sensitivity, with GPX4 as the top sensitiser in both screens. Depletion or inhibition of GPX4 increases sensitivity to palbociclib and giredestrant, and their combination, in ER+ breast cancer models, with GPX4 null xenografts being highly sensitive to palbociclib. GPX4 perturbation additionally sensitises triple negative breast cancer (TNBC) models to palbociclib. Palbociclib and giredestrant induced oxidative stress and disordered lipid metabolism, leading to a ferroptosis-sensitive state. Lipid peroxidation is promoted by a peroxisome AGPAT3-dependent pathway in ER+ breast cancer models, rather than the classical ACSL4 pathway. Our data demonstrate that CDK4/6 and ER inhibition creates vulnerability to ferroptosis induction, that could be exploited through combination with GPX4 inhibitors, to enhance sensitivity to the current therapies in breast cancer.
While CDK4/6 inhibitors (CDK4/6i) have improved outcomes for breast cancer patients, estrogen receptor (ER + ) breast cancers often develop resistance, and triple negative breast cancer (TNBC) show poor sensitivity. Here, the authors identify a vulnerability of CDK4/6i treated ER+ and TNBC on ferroptosis and identify the combination of CDK4/6i and GPX4 inhibition as synergistic.
Journal Article
New species and records of Trichoderma isolated as mycoparasites and endophytes from cultivated and wild coffee in Africa
A survey for species of the genus
Trichoderma
occurring as endophytes of
Coffea,
and as mycoparasites of coffee rusts (
Hemileia
), was undertaken in Africa; concentrating on Cameroon and Ethiopia. Ninety-four isolates of
Trichoderma
were obtained during this study: 76 as endophytes of healthy leaves, stems and berries and, 18 directly from colonized rust pustules. A phylogenetic analysis of all isolates used a combination of three genes: translation elongation factor-1α (
tef1
),
rpb2
and
cal
for selected isolates. GCPSR criteria were used for the recognition of species; supported by morphological and cultural characters. The results reveal a previously unrecorded diversity of
Trichoderma
species endophytic in both wild and cultivated
Coffea
, and mycoparasitic on
Hemileia
rusts. Sixteen species were delimited, including four novel taxa which are described herein:
T. botryosum
,
T. caeruloviride
,
T. lentissimum
and
T. pseudopyramidale
. Two of these new species,
T
.
botryosum
and
T
.
pseudopyramidale
, constituted over 60% of the total isolations, predominantly from wild
C
.
arabica
in Ethiopian cloud forest. In sharp contrast, not a single isolate of
Trichoderma
was obtained using the same isolation protocol during a survey of coffee in four Brazilian states, suggesting the existence of a ‘
Trichoderma
void’ in the endophyte mycobiota of coffee outside of Africa. The potential use of these African
Trichoderma
isolates in classical biological control, either as endophytic bodyguards—to protect coffee plants from
Hemileia vastatrix
, the fungus causing coffee leaf rust (CLR)—or to reduce its impact through mycoparasitism, is discussed, with reference to the on-going CLR crisis in Central America.
Journal Article
Dust content solutions for the Alcubierre warp drive spacetime
The Alcubierre metric is a spacetime geometry where a massive particle inside a spacetime distortion, called warp bubble, is able to travel at velocities arbitrarily higher than the velocity of light, a feature known as the warp drive. This is a consequence of general relativity, which allows for global superluminal velocities but restricts local speeds to subluminal ones as required by special relativity. In this work we solved the Einstein equations for the Alcubierre warp drive spacetime geometry considering the dust matter distribution as source, since the Alcubierre metric was not originally advanced as a solution of the Einstein equations, but as a spacetime geometry proposed without a source gravity field. We found that all Einstein equations solutions of this geometry containing pressureless dust lead to vacuum solutions. We also concluded that these solutions connect the Alcubierre metric to the Burgers equation, which describes shock waves moving through an inviscid fluid. Our results also indicated that these shock waves behave as plane waves.
Journal Article