The crystallographic analysis of the structures of danburite CaSi
2
B
2
O
8
, which is orthorhombic (
Pnma
) at normal pressure, triclinic (
P
1
¯
) at a pressure of 25.4 GPa, and monoclinic (
P
2
1
.../
c
) at a pressure of 32.3 GPa, shows that they are based on a joint packing of Ca cations and O anions whose regularity increases with pressure. A common structural fragment is the configuration of atoms related by the glide reflection plane retaining for Ca and a part of O, B positions with a possible Si migration according to the seesaw mechanism (N. V. Belov).
Marine alkaloids belonging to the lamellarins family, which incorporate a 5,6-dihydro-1-phenylpyrrolo2,1-
isoquinoline (DHPPIQ) moiety, possess various biological activities, spanning from antiviral ...and antibiotic activities to cytotoxicity against tumor cells and the reversal of multidrug resistance. Expanding a series of previously reported imino adducts of DHPPIQ 2-carbaldehyde, novel aliphatic and aromatic Schiff bases were synthesized and evaluated herein for their cytotoxicity in five diverse tumor cell lines. Most of the newly synthesized compounds were found noncytotoxic in the low micromolar range (<30 μM). Based on a Multi-fingerprint Similarity Search aLgorithm (MuSSeL), mainly conceived for making protein drug target prediction, some DHPPIQ derivatives, especially bis-DHPPIQ Schiff bases linked by a phenylene bridge, were prioritized as potential hits addressing Alzheimer's disease-related target proteins, such as cholinesterases (ChEs) and monoamine oxidases (MAOs). In agreement with MuSSeL predictions, homobivalent
-phenylene DHPPIQ Schiff base
exhibited a noncompetitive/mixed inhibition of human acetylcholinesterase (AChE) with
in the low micromolar range (4.69 μM). Interestingly, besides a certain inhibition of MAO A (50% inhibition of the cell population growth (IC
) = 12 μM), the bis-DHPPIQ
showed a good inhibitory activity on self-induced β-amyloid (Aβ)
aggregation (IC
= 13 μM), which resulted 3.5-fold stronger than the respective mono-DHPPIQ Schiff base
.
The aim of these clinical standards is to provide guidance on 'best practice´ for diagnosis, treatment and management of drug-susceptible pulmonary TB (PTB).
A panel of 54 global experts in the field ...of TB care, public health, microbiology, and pharmacology were identified; 46 participated in a Delphi process. A 5-point Likert scale was used to score draft standards. The final document represents the broad consensus and was approved by all 46 participants.
Seven clinical standards were defined: Standard 1, all patients (adult or child) who have symptoms and signs compatible with PTB should undergo investigations to reach a diagnosis; Standard 2, adequate bacteriological tests should be conducted to exclude drug-resistant TB; Standard 3, an appropriate regimen recommended by WHO and national guidelines for the treatment of PTB should be identified; Standard 4, health education and counselling should be provided for each patient starting treatment; Standard 5, treatment monitoring should be conducted to assess adherence, follow patient progress, identify and manage adverse events, and detect development of resistance; Standard 6, a recommended series of patient examinations should be performed at the end of treatment; Standard 7, necessary public health actions should be conducted for each patient. We also identified priorities for future research into PTB.
These consensus-based clinical standards will help to improve patient care by guiding clinicians and programme managers in planning and implementation of locally appropriate measures for optimal person-centred treatment for PTB.
New transparent optodes for life-time based microscopic imaging of O₂ were developed by spin-coating a μm-thin layer of a highly luminescent cyclometalated iridium(III) coumarin complex in ...polystyrene onto glass cover slips. Compared to similar thin-film O₂ optodes based on a ruthenium(II) polypyridyl complex or a platinum(II) porphyrin, the new planar sensors have i) higher brightness allowing for much shorter exposure times and thus higher time resolution, ii) more homogeneous and smaller pixel to pixel variation over the sensor area resulting in less noisy O₂ images, and iii) a lower temperature dependency simplifying calibration procedures. We used the new optodes for microscopic imaging of the spatio-temporal O₂ dynamics at the base of heterotrophic biofilms in combination with confocal imaging of bacterial biomass and biofilm structure. This allowed us to directly link biomass distribution to O₂ distribution under both steady state and non-steady state conditions. We demonstrate that the O₂ dynamics in biofilms is governed by a complex interaction between biomass distribution, mass transfer and flow that cannot be directly inferred from structural information on biomass distribution alone.
•We fully characterized the new thermographic phosphor Cr3+:YAB in a wide temperature range.•The measurements are used to determine the optimal parameters for an optical temperature sensor.•We ...demonstrate how this material enables sensitive, low-cost, and robust temperature sensing.•This phosphor can be used for biological imaging, medicine, and environmental monitoring.
The luminescence emission of a new thermographic phosphor based on Chromium(III)-doped yttrium aluminum borate (Cr3+:YAB) has a strong temperature dependence, which makes this material well suited for temperature sensing. In this work the luminescence emission decay was investigated in great detail in a broad temperature range, both in time and frequency domain. The results obtained with these two measuring techniques, which are consistent, are used to determine the optimal design parameters for sensor development. The high sensitivity which is thus achievable, together with the high stability of the material, demonstrate that this phosphor is very suitable for the design of a sensitive, low-cost, and robust contactless temperature sensor. Due to the insensitivity of the sensing properties to the immobilization matrix, this material can be easily incorporated in the most appropriate matrix depending on the application.
Synthetic methods were developed for isopimaric acid derivatives, the terminal carboxylic acid of which was separated by two or three methylenes from the tricyclic skeleton. Their anti-inflammatory ...activity was studied. A Wittig reaction of isopimarinal (obtained from isopimaric acid) with the phosphorus ylide generated from methoxymethyl(triphenyl)phosphonium chloride using butyllithium formed a mixture of (Z)- and (E)-alkenes (54% yield) and 4-(Z)-pentenyl-18-nor-isopimara-7,15-diene (17% yield). Hydrolysis of the mixture of enol ethers by p-toluenesulfonic acid in Me
2
CO produced 4-(2-oxoethyl)-18-nor-isopimara-7,15-diene. Olefination of pimarinal and its homolog by a Horner–Wadsworth–Emmons reaction led to the corresponding ethers of (E)-alkenes (81–85% yield). Reduction of the double bond by Mg in MeOH and hydrolysis of the ethers proceeded smoothly to the corresponding 4-(carboxyalkyl)-18-nor-isopimara-7,15-dienes (74 and 88% yield). The structure of 4-(2-carboxyethyl)-18-nor-isopimara-7,15-diene was established by an X-ray crystal structure analysis. Significant anti-inflammatory activity of the new C4-modified isopimaric acid derivatives was found in in vivo tests.
Four detailed chemical mechanisms used to describe detonation combustion of hydrogen in oxygen are considered. Ignition delays for various temperatures and pressures are found, the Chapman–Jouguet ...velocity is determined, and the Zel’dovich–von Neumann–Döring solution for different models is obtained. The effect of dilution of the stoichiometric mixture of hydrogen and oxygen by an inert gas is estimated. Direct numerical simulation of detonation wave propagation in a channel is performed. The emergence of instability of the plane wave and formation of a cellular (multifront) structure are studied. The results predicted by different chemical models are analyzed and compared with each other and with available experimental data.
Organophosphazenes are of interest due to the combination of increased mechanical and thermal properties of polymer materials obtained with their use, however, they are characterized by a complex ...multi-stage synthesis. Moreover, the high viscosity of phosphazene-containing epoxy resins (PhER) makes their processing difficult. To simplify the synthesis of PhER, a one-step method was developed, and bisphenol F was chosen, which also provided a decrease in viscosity. In the current study, PhER were formed by a one-stage interaction of hexachlorocyclotriphosphazene (HCP) with bisphenol F isomers and epichlorohydrin in the presence of alkali, which was a mixture of epoxycyclophosphazenes (ECPh) with a functionality from 1 to 4 according to the results of MALDI-TOF analysis. Conventional epoxy resins based on bisphenol F, also formed during the process, showed high mechanical properties and glass transition temperature, and the reactivity of the obtained resins is similar to the base epoxy resins based on bisphenols A and F. Cured PhER had higher or the same mechanical properties compared to base epoxy resins based on bisphenol A and F, and a glass transition temperature comparable to base epoxy resins based on bisphenol F: glass transition temperature (Tg) up to 174.5 °C, tensile strength up to 74.5 MPa, tensile modulus up to 2050 MPa, tensile elongation at break up to 6.22%, flexural strength up to 146.6 MPa, flexural modulus up to 3630 MPa, flexural elongation at break up to 9.15%, and Izod impact strength up to 4.01 kJ/m2. Analysis of the composition of the obtained PhER was carried out by 1H and 31P NMR spectroscopy, MALDI-TOF mass spectrometry, X-ray fluorescence elemental analysis, and contained up to 3.9% phosphorus and from 1.3% to 4.2% chlorine. The temperature profile of the viscosity of the resulting epoxy resins was determined, and the viscosity at 25 °C ranged from 20,000 to 450,000 Pa·s, depending on the ratio of reagents. The resins studied in this work can be cured with conventional curing agents and, with a low content of the phosphazene fraction, can act as modifiers for traditional epoxy resins, being compatible with them, to increase impact strength and elasticity while maintaining the rest of the main mechanical and processing properties, and can be used as a resin component for composite materials, adhesives, and paints.
The crystallographic analysis of the structures of Hg
7
As
4
(AgI
3
)
2
(
I
), Hg
6
As
4
Br
3
(SnBr
3
) (
II
), and Hg
11
As
4
(GaBr
4
)
4
(
III
) treated as host-guest structures is performed. It is ...shown that the spatial basis (“skeleton”) of the structures is formed by crystallographic planes densely occupied by mercury and halogen atoms. The cubic symmetry of the first two structures is initiated by the local symmetry of the (As
2
Hg
6
) building block. The
C
2/
m
symmetry of the third structure is initiated by the 2/
m
local symmetry of the blocks with linear groups containing Hg
2
and Hg
3
fragments.
As a result of the crystallographic analysis of the structures of borates BaNaSc(BO
3
)
2
(I) and K
7
CaY
2
(B
5
O
10
)
3
(II), a model of the formation of stable atomic groups (templates) with high ...point symmetry is proposed and a coherent assembly of these groups by the planes of pseudo cubic cation sublattices with the point symmetry spread on the whole structure is shown.
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