In this work, wormholes, tunnel like structures introduced by Morris and Thorne (Am J Phys 56:395,
1988
), are explored within the framework of
f
(
R
) gravity. Using the shape function
b
(
r
)
=
r
0
...(
r
r
0
)
γ
, where
0
<
γ
<
1
, and the equation of state
p
r
=
ω
ρ
, the
f
(
R
) function is derived and the field equations are solved. Then null, weak, strong and dominated energy conditions are analyzed and spherical regions satisfying these energy conditions are determined. Furthermore, we calculated the range of the radius of the throat of the wormhole, where the energy conditions are satisfied.
Summary
Macrophages are extremely heterogeneous and plastic cells with an important role not only in physiological conditions, but also during inflammation (both for initiation and resolution). In ...the early 1990s, two different phenotypes of macrophages were described: one of them called classically activated (or inflammatory) macrophages (M1) and the other alternatively activated (or wound‐healing) macrophages (M2). Currently, it is known that functional polarization of macrophages into only two groups is an over‐simplified description of macrophage heterogeneity and plasticity; indeed, it is necessary to consider a continuum of functional states. Overall, the current available data indicate that macrophage polarization is a multifactorial process in which a huge number of factors can be involved producing different activation scenarios. Once a macrophage adopts a phenotype, it still retains the ability to continue changing in response to new environmental influences. The reversibility of polarization has a critical therapeutic value, especially in diseases in which an M1/M2 imbalance plays a pathogenic role. In this review, we assess the high plasticity of macrophages and their potential to be exploited to reduce chronic/detrimental inflammation. On the whole, the evidence detailed in this review underscores macrophage polarization as a target of interest for immunotherapy.
“Classification in pro‐inflammatory (M1) and anti‐inflammatory (M2) macrophages is a simplified view of the heterogeneity and plasticity of these cells; it is necessary to consider a continuum of functional states. The reversibility of polarization has a critical therapeutic value, especially in diseases where M1/M2 imbalance has a pathogenic role. In this review, we assess the high plasticity of macrophages and highlight macrophage polarization as an interesting target for immunotherapy.”
Modified gravity theories have received increased attention lately to understand the late time acceleration of the universe. This viewpoint essentially modifies the geometric components of the ...universe. Among numerous extension to Einstein’s theory of gravity, theories which include higher order curvature invariant, and specifically the class of
f
(
R
) theories, have received several acknowledgments. In our current work we try to understand the late time acceleration of the universe by modifying the geometry of the space and using dynamical system analysis. The use of this technique allows to understand the behavior of the universe under several circumstances. Apart from that we study the stability properties of the critical point and acceleration phase of the universe which could then be analyzed with observational data. We consider a particular model
f
(
R
)
=
R
-
μ
R
c
(
R
/
R
c
)
p
with
0
<
p
<
1
,
μ
,
R
c
>
0
for the study. As a first case we consider the matter and radiation component of the universe with an assumption of no interaction between them. Later, as a second case we take matter, radiation and dark energy (cosmological constant) where study on effects of linear, non-linear and no interaction between matter and dark energy is considered and results have been discussed in detail.
Direct alkylations of carboxylic acid derivatives are challenging and particularly nickel catalysis commonly requires high reaction temperatures and strong bases, translating into limited substrate ...scope. Herein, nickel‐catalyzed C−H alkylations of unactivated 8‐aminoquinoline amides have been realized under exceedingly mild conditions, namely at room temperature, with a mild base and a user‐friendly electrochemical setup. This electrocatalyzed C−H alkylation displays high functional group tolerance and is applicable to both the primary and secondary alkylation. Based on detailed mechanistic studies, a nickel(II/III/I) catalytic manifold has been proposed.
Electrochemically enabled nickel‐catalyzed C−H alkylations with primary and secondary alkyl halides have been accomplished under exceedingly mild reaction conditions with Et3N at room temperature. Detailed mechanistic studies provided support for a nickel(II/III/I) manifold.
Inexpensive cobalt‐catalyzed oxidative C−H functionalization has emerged as a powerful tool for the construction of C−C and C−Het bonds, which offers unique potential for transformative applications ...to modern organic synthesis. In the early stage, these transformations typically required stoichiometric and toxic transition metals as sacrificial oxidants; thus, the formation of metal‐containing waste was inevitable. In contrast, naturally abundant molecular O2 has more recently been successfully employed as a green oxidant in cobalt catalysis, thus considerably improving the sustainability of such transformations. Recently, a significant momentum was gained by the use of electricity as a sustainable and environmentally benign redox reagent in cobalt‐catalyzed C−H functionalization, thereby preventing the consumption of cost‐intensive chemicals while at the same time addressing the considerable safety hazards related to the use of molecular oxygen in combination with flammable organic solvents. Considering the unparalleled potential of the aforementioned approaches for sustainable green synthesis, this Review summarizes the recent progress in cobalt‐catalyzed oxidative C−H activation until early 2020.
Metal‐catalyzed C−H activation has emerged as an increasingly powerful tool for molecular synthesis, with major advances achieved by using Earth‐abundant cobalt catalysts. Recent momentum was gained by oxidative C−H transformations, prominently featuring aerobic and electrochemical approaches. Herein, the findings in this topical area of sustainable synthesis are summarized and critically discussed.
Electrophilic halogenation is used to produce a wide variety of halogenated compounds. Previously reported methods have been developed mainly using a reagent‐based approach. Unfortunately, a suitable ...“catalytic” process for halogen transfer reactions has yet to be achieved. In this study, arylamines have been found to generate an N‐halo arylamine intermediate, which acts as a highly reactive but selective catalytic electrophilic halogen source. A wide variety of heteroaromatic and aromatic compounds are halogenated using commercially available N‐halosuccinimides, for example, NCS, NBS, and NIS, with good to excellent yields and with very high selectivity. In the case of unactivated double bonds, allylic chlorides are obtained under chlorination conditions, whereas bromocyclization occurs for polyolefin. The reactivity of the catalyst can be tuned by varying the electronic properties of the arene moiety of catalyst.
Truly catalytic halogenation: Aniline was found to be a versatile catalyst for selective halogenation reactions. The catalytic method was used for selective halogenations of aromatic and heteroaromatic compounds as well as unactivated double bonds using commercially available N‐halosuccinimides (NXS: X=Cl, Br, I).
Nickel‐catalyzed electrochemical C−H aminations were accomplished by chemo‐ and position‐selective C−H activation with ample scope. Detailed mechanistic studies highlighted a facile C−H cleavage with ...unique chemo‐selectivity, while cyclovoltammetric analysis provided support for a nickel(II/III/IV) manifold.
II…III…IV: Nickel‐catalyzed C−H aminations proved viable with electricity as the sole oxidant by fast C−H cleavage involving nickel(IV) species.
•PCV10 reduced IPD caused by vaccine serotypes of Streptococcus pneumoniae.•PCV10 reduced IPD by vaccine serotypes in the non-targeted population.•IPD by serotypes 3, 6C, and 19A increased after the ...introduction of PCV10.
In March 2010, the 10-valent pneumococcal conjugate vaccine (PCV10) was introduced into the routine immunization program in Brazil. We describe the pneumococcal serotypes that caused invasive pneumococcal diseases (IPD) before and after the introduction of PCV10 using data from a national laboratory-based surveillance system.
We compared the prevalence of vaccine types (VT) and non-vaccine types (NVT) of Streptococcus pneumoniae in three periods, pre-PCV10 (January/2005-December/2009), early post-PCV10 (January/2010-December/2013), and late post-PCV10 (January/2014-December/2015), by episode in meningitis and non-meningitis cases and by age group. Changes in serotype prevalence in the early and late post-PCV10 periods were determined using pre-PCV10 period as a reference.
A total of 8971 IPD isolates from patients aged 2 months to 99 years were analyzed. In the late post-PCV10 period, the VT-IPD reduction in the 2-month to 4-year age group was 83.4% for meningitis and 87.4% for non-meningitis cases; in the age groups 5–17 years, 18–64 years, and ≥65 years, VT declined by 56.1%, 54.1%, and 47.4%, respectively, in meningitis cases, and by 60.9%, 47.7%, and 53.4%, respectively, in non-meningitis cases. NVT-IPD increased throughout the study period, driven mainly by serotypes 3, 6C, and 19A, which remained the predominant types causing IPD in the late post-PCV10 period.
We observed direct and indirect PCV10 protection against IPD caused by VT and a shift in the distribution of serotypes 5 years after the introduction of PCV10. Continued IPD surveillance is needed to evaluate the sustainability of the high prevalence of serotypes 3, 6C, and 19A, which were not included in PCV10.
Trypanosoma cruzi, the protozoan agent of Chagas disease in the Americas, is comprised of six genetic lineages (TcI-TcVI) and a possible seventh (TcBat, related to TcI). Identification of T. cruzi ...lineages infecting reservoir mammalian species is fundamental to resolving transmission cycles. However, this is hindered by the limited sensitivity and technical complexity of parasite isolation and genotyping. An alternative approach is serology using T. cruzi lineage-specific epitopes, such as those of the trypomastigote small surface antigen (TSSA). For surveillance of T. cruzi lineage infections in mammal species from diverse Brazilian regions, we apply a novel rapid diagnostic test (RDT, Chagas Sero K-SeT), which incorporates the TSSA peptide epitope specific to TcII/V/VI (TSSApep-II/V/VI) and Protein G detection of antibodies. Chagas Sero K-SeT RDT results with sera from experimentally infected mice, from tamarin primates (Leontopithecus spp.) and from canines (Canis familiaris) were concordant with corresponding TSSApep-II/V/VI ELISAs. The Chagas Sero K-Set detected TcII/V/VI infections in Leontopithecus spp. from the Atlantic forest (n = 46), in C. familiaris (n = 16) and Thrichomys laurentius (n = 2) from Caatinga biome and Chiroptera (n = 1) from Acre, Amazonia. The Chagas Sero K-SeT RDT is directly applicable to TcII/V/VI-specific serological surveillance of T. cruzi infection in several different mammalian Orders. It can replace ELISAs and provides efficient, point-of-sampling, low-cost detection of TcII/V/VI infections, with at least equivalent sensitivity, although some mammals may be difficult to trap, and, not unexpectedly, Chagas Sero K-SeT could not recognise feline IgG. Knowledge of sylvatic hosts of T. cruzi can be expanded, new reservoir species discovered, and the ecology of transmission cycles clarified, particularly with adaptation to further mammalian Orders.
Heme oxygenase (HO) is the primary antioxidant enzyme involved in heme group degradation. A variety of stimuli triggers the expression of the inducible HO-1 isoform, which is modulated by its ...substrate and cellular stressors. A major anti-inflammatory role has been assigned to the HO-1 activity. Therefore, in recent years HO-1 induction has been employed as an approach to treating several disorders displaying some immune alterations components, such as exacerbated inflammation or self-reactivity. Many natural compounds have shown to be effective inductors of HO-1 without cytotoxic effects; among them, most are chemicals present in plants used as food, flavoring, and medicine. Here we discuss some naturally derived compounds involved in HO-1 induction, their impact in the immune response modulation, and the beneficial effect in diverse autoimmune disorders. We conclude that the use of some compounds from natural sources able to induce HO-1 is an attractive lifestyle toward promoting human health. This review opens a new outlook on the investigation of naturally derived HO-1 inducers, mainly concerning autoimmunity.
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