The standard (
p
∘
=
0.1
MPa) molar enthalpies of formation of 2-, 3-, and 4-chloronitrobenzene isomers, in the crystalline state, at
T
=
298.15
K, were derived from the standard (
p
∘
=
0.1
MPa) ...massic energies of combustion, in oxygen, at
T
=
298.15
K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies of sublimation of the isomers, at
T
=
298.15
K, were obtained by high temperature Calvet microcalorimetry.
-
Δ
c
U
m
∘
(
cr
)
/(kJ
·
mol
−1)
-
Δ
c
H
m
∘
(
cr
)
/(kJ
·
mol
−1)
-
Δ
cr
g
H
m
∘
/(kJ
·
mol
−1)
2-Chloronitrobenzene
2939.5
±
0.7
18.7
±
1.0
80.9
±
1.5
3-Chloronitrobenzene
2915.8
±
0.8
42.4
±
1.2
82.5
±
1.5
4-Chloronitrobenzene
2921.7
±
1.4
36.5
±
1.6
76.2
±
2.1
From the determined experimental data, the values of the gaseous standard (
p
∘
=
0.1
MPa) molar enthalpies of formation for the three monochloronitrobenzene isomers were derived. The gas-phase enthalpies of formation were also estimated by the empirical scheme developed by Cox showing that for
meta- and
para-chloronitrobenzene the estimated values are in close agreement with the experimental ones whereas, in the case of
ortho-chloronitrobenzene it is shown that a different enthalpic interaction increment is needed, when the substituents in the adjacent carbon ring atoms are a chlorine atom and a nitro group.
The standard (
p
∘
=
0.1
MPa
) molar enthalpies of formation of 2,4,6-trichloronitrobenzene, 2,3,5,6-tetrachloronitrobenzene, and pentachloronitrobenzene, in the crystalline state, at
T
=
298.15
K, ...were derived from the standard massic energies of combustion, in oxygen, at
T
=
298.15
K, measured by rotating-bomb combustion calorimetry.
The standard molar enthalpies of sublimation, at
T
=
298.15
K, of 2,4,6-trichloronitrobenzene and pentachloronitrobenzene, were determined from the dependence with the temperature of the vapour pressures, measured by the Knudsen mass-loss effusion method, whereas for 2,3,5,6-tetrachloronitrobenzene, the Calvet drop microcalorimetric technique was used.
-
Δ
c
U
m
∘
(
cr
)
/(kJ
·
mol
−1)
-
Δ
f
H
m
∘
(
cr
)
/(kJ
·
mol
−1)
Δ
cr
g
H
m
∘
/(kJ
·
mol
−1)
2,4,6-Trichloronitrobenzene
2663.5
±
1.1
58.6
±
1.3
86.7
±
1.1
2,3,5,6-Tetrachloronitrobenzene
2537.1
±
1.7
67.0
±
1.9
91.3
±
2.5
Pentachloronitrobenzene
2387.4
±
2.4
98.6
±
2.5
94.5
±
0.4
The experimental values are also compared with estimates based on G3(MP2)//B3LYP computations, which have also been extended to all the isomers of the trichloro- and tetrachloronitrobenzene that were not studied experimentally.
The standard (
p°
=
0.1
MPa) molar enthalpies of formation of 2,4-, 2,5-, 3,4- and 3,5-dichloronitrobenzene isomers, in the crystalline state, at
T
=
298.15
K, were derived from the standard (
p°
=
...0.1
MPa) massic energies of combustion, in oxygen, at
T
=
298.15
K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies of sublimation of the four isomers, at
T
=
298.15
K, were obtained by high-temperature Calvet microcalorimetry.
-
Δ
c
U
m
∘
(
cr
)
/
(
kJ
·
mol
-
1
)
-
Δ
f
H
m
∘
(cr)
/
(
kJ
·
mol
-
1
)
Δ
cr
g
H
m
∘
/
(
kJ
·
mol
-
1
)
2,4-Dichloronitrobenzene
2792.8
±
0.9
47.4
±
1.2
87.8
±
1.7
2,5-Dichloronitrobenzene
2793.0
±
1.8
47.2
±
2.0
87.4
±
2.5
3,4-Dichloronitrobenzene
2774.1
±
1.2
66.1
±
1.4
85.8
±
2.5
3,5-Dichloronitrobenzene
2769.6
±
0.9
70.6
±
1.2
83.2
±
1.5
From the determined experimental results, the values of the gaseous standard (
p°
=
0.1
MPa) molar enthalpies of formation were derived. The gas-phase enthalpies of formation of all the six chloronitrobenzene isomers were also estimated by the Cox scheme and by computational thermochemistry methods and compared with the available experimental values.
The standard (p∘=0.1MPa) molar enthalpies of formation, at T=298.15K, of 4-chloro-3-nitroaniline and 5-chloro-2-nitroaniline, in the condensed phase, were derived from their standard molar energies ...of combustion, in oxygen, to yield CO2(g), N2(g), and HCl·600H2O(l), measured by rotating bomb combustion calorimetry. From the temperature dependence of the vapour pressures of these compounds, measured by the Knudsen effusion technique, their standard molar enthalpies of sublimation, at T=298.15K, were derived by means of the Clausius–Clapeyron equation. The Calvet microcalorimetry was also used to measure the standard molar enthalpies of sublimation of these compounds, at T=298.15K. The combination of the standard molar enthalpies of formation in the condensed phases and the standard molar enthalpies of sublimation yielded the standard molar enthalpies of formation in the gaseous phase at T=298.15K for each isomer. Further, the standard (p∘=0.1MPa) molar enthalpies, entropies and Gibbs free energies of sublimation, at T=298.15K, were also derived.
The standard molar enthalpies of formation, in the gaseous phase of all the chloronitroaniline isomers were also estimated by the Cox scheme and by the use of computational thermochemistry and compared with the available experimental values.
Appropriate use and interpretation of serological tests for assessments of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure, infection and potential immunity require accurate ...data on assay performance. We conducted a head-to-head evaluation of ten point-of-care-style lateral flow assays (LFAs) and two laboratory-based enzyme-linked immunosorbent assays to detect anti-SARS-CoV-2 IgM and IgG antibodies in 5-d time intervals from symptom onset and studied the specificity of each assay in pre-coronavirus disease 2019 specimens. The percent of seropositive individuals increased with time, peaking in the latest time interval tested (>20 d after symptom onset). Test specificity ranged from 84.3% to 100.0% and was predominantly affected by variability in IgM results. LFA specificity could be increased by considering weak bands as negative, but this decreased detection of antibodies (sensitivity) in a subset of SARS-CoV-2 real-time PCR-positive cases. Our results underline the importance of seropositivity threshold determination and reader training for reliable LFA deployment. Although there was no standout serological assay, four tests achieved more than 80% positivity at later time points tested and more than 95% specificity.
The success of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the treatment of hematological malignancies remains hampered by life-threatening chronic graft vs. host disease ...(cGVHD). Although multifactorial in nature, cGVHD has been associated with imbalances between effector and regulatory T cells (Treg). To further elucidate this issue, we performed a prospective analysis of patients undergoing unrelated donor allo-HSCT after a reduced intensity conditioning (RIC) regimen containing anti-thymocyte globulin (ATG) and the same GVHD prophylaxis, at a single institution. We studied T cell subset homeostasis over a 24-month follow-up after HSCT in a comparative analysis of patients with and without cGVHD. We also quantified naive and memory T cell subsets, proliferation and expression of the apoptosis-related proteins Bcl-2 and CD95. Finally, we assessed thymic function by T cell receptor excision circle (TREC) quantification and T cell receptor (TCR) diversity by TCRVβ spectratyping. While the total number of conventional CD4 (Tcon) and CD8 T cells was similar between patient groups, Treg were decreased in cGVHD patients. Interestingly, we also observed divergent patterns of Naive and Stem Cell Memory (SCM) subset recovery in Treg and Tcon compared to CD8. Patients with cGVHD showed impaired recovery of Naive and SCM Tcon and Treg, but significantly increased frequencies and absolute numbers of Naive and SCM were observed in the CD8 pool. Markedly increased EMRA CD8 T cells were also noted in cGVHD. Taken together, these results suggest that Naive, SCM and EMRA CD8 play a role in the emergence of cGHVD. Reduced Naive and recent thymic emigrant Tcon and Treg in cGVHD was likely due to impaired thymic output, as it was accompanied by decreased CD4 TREC and TCR diversity. On the other hand, CD8 TCR diversity was similar between patient groups. Furthermore, no correlation was observed between CD8 TREC content and Naive CD8 numbers, suggesting limited thymic production of Naive CD8 T cells in patients after transplant, especially in those developing cGVHD. The mechanisms behind the opposing patterns of CD4 and CD8 subset cell recovery in cGVHD remain elusive, but may be linked to thymic damage associated with the conditioning regimen and/or acute GVHD.
We describe the epidemiological characteristics, pattern of circulation, and geographical distribution of influenza B viruses and its lineages using data from the Global Influenza B Study. We ...included over 1.8 million influenza cases occurred in thirty-one countries during 2000-2018. We calculated the proportion of cases caused by influenza B and its lineages; determined the timing of influenza A and B epidemics; compared the age distribution of B/Victoria and B/Yamagata cases; and evaluated the frequency of lineage-level mismatch for the trivalent vaccine. The median proportion of influenza cases caused by influenza B virus was 23.4%, with a tendency (borderline statistical significance, p = 0.060) to be higher in tropical vs. temperate countries. Influenza B was the dominant virus type in about one every seven seasons. In temperate countries, influenza B epidemics occurred on average three weeks later than influenza A epidemics; no consistent pattern emerged in the tropics. The two B lineages caused a comparable proportion of influenza B cases globally, however the B/Yamagata was more frequent in temperate countries, and the B/Victoria in the tropics (p = 0.048). B/Yamagata patients were significantly older than B/Victoria patients in almost all countries. A lineage-level vaccine mismatch was observed in over 40% of seasons in temperate countries and in 30% of seasons in the tropics. The type B virus caused a substantial proportion of influenza infections globally in the 21st century, and its two virus lineages differed in terms of age and geographical distribution of patients. These findings will help inform health policy decisions aiming to reduce disease burden associated with seasonal influenza.
Mast cells have recently gained new importance as immunoregulatory cells that are involved in numerous pathological processes. One result of these processes is an increase in mast cell numbers at ...peripheral sites. This study was undertaken to determine the mast cell response in the peritoneal cavity and bone marrow during repopulation of the peritoneal cavity in rats.
Two mast cell specific antibodies, mAb AA4 and mAb BGD6, were used to distinguish the committed mast cell precursor from more mature mast cells. The peritoneal cavity was depleted of mast cells using distilled water. Twelve hours after distilled water injection, very immature mast cells could be isolated from the blood and by 48 hours were present in the peritoneal cavity. At this same time the percentage of mast cells in mitosis increased fourfold. Mast cell depletion of the peritoneal cavity also reduced the total number of mast cells in the bone marrow, but increased the number of mast cell committed precursors.
In response to mast cell depletion of the peritoneal cavity, a mast cell progenitor is released into the circulation and participates in repopulation of the peritoneal cavity, while the committed mast cell precursor is retained in the bone marrow.
Notas breves María Temes-Casas; Ángela Noguerol Seoane; Ana Rifon Lastra ...
Anales del Jardín Botánico de Madrid (1979),
12/2001, Letnik:
59, Številka:
2
Journal Article
PDF
