Plasma disappearance curves using multiple blood samples are a recognized reference method for measuring glomerular filtration rate (GFR). However, there is no consensus on the protocol for this type ...of measurement. A two-compartment model is generally considered acceptable for the mathematical description of the concentration-time decay curve. The impact of the fitting procedure on the reported GFR has not been questioned.We defined 8 different fitting procedures to calculate the area under the curve, and from this area under the curve, the GFR. We applied the 8 fitting methods (all considering a full concentration-time curve) on the multiple sample data (8 samples) of 20 children diagnosed with Duchenne muscular dystrophy. We evaluated the effect (variability) on the reported GFR from the different fitting methods and compared these results with GFR-values calculated from late samples only (samples after 120 minutes) and from one-sample methods.In 6 out of 20 cases, the fitting methods on the full concentration-time curve resulted in very different reported GFR-values, mainly because some methods were not able to fit the data, or methods resulted in GFR-values ranging from 0 to 120 mL/min. The reported GFR-result therefore strongly depends on the fitting method, making the full concentration-time method less robust than expected. Compared with a consensus reference GFR, the late sample models did not show fitting issues and may therefore be considered as more robust. Also the one-sample methods showed acceptable accuracy.The late sample methods (using 3 time-points) provide robust and reliable methods to determine GFR.
The use of tetra-alkylcarbamides as novel ligands: N,N-butyl-N’,N’-hexylurea (L1: ABHU), and N,N-butyl-N’,N’-pentylurea (L2: ABPU), for the solvent extraction and complexation behaviors of ...uranium(VI) was synthesized and investigated in this study. The effects of HNO3 and NO3− concentrations in the aqueous phase on the distribution ratio of U(VI) were examined. Under 5 mol/L HNO3 concentration, DU reached 5.02 and 4.94 respectively without third-phase formation. During the extraction, slope measurements and IR spectral analysis revealed that the U(VI) complexes are a form of UO2(NO3)2·2L for both ligands. In addition, thermodynamic studies showed that the uranium extraction reaction was a spontaneous exothermic reaction. The deep structural analysis of the complexes was realized with DFT calculation. The bond length, bond properties, and topology of the complexes were discussed in detail to analyze the extraction behavior. This study enriches the coordination chemistry of U(VI) by tetra-alkylcarbamides, which may offer new clues for the design and synthesis of novel ligands for the separation, enrichment, and recovery of uranium in the nuclear fuel cycle.
A small library of highly functionalized phenylaminopyrazoles, bearing different substituents at position 1, 3, and 4 of the pyrazole ring, was prepared by the one-pot condensation of active ...methylene reagents, phenylisothiocyanate, and substituted hydrazine (namely, methyl- and benzyl-hydrazine). The identified reaction conditions proved to be versatile and efficient. Furthermore, the evaluation of alternative stepwise protocols affected the chemo- and regio-selectivity outcome of the one-pot procedure. The chemical identities of two N-methyl pyrazole isomers, selected as prototypes of the whole series, were unambiguously identified by means of NMR and mass spectrometry studies. Additionally, semiempirical calculations provided a structural rationale for the different chromatographic behavior of the two isomers. The prepared tetra-substituted phenylaminopyrazoles were tested in cell-based assays on a panel of cancer and normal cell lines. The tested compounds did not show any cytotoxic effect on the selected cell lines, thus supporting their pharmaceutical potentials.
Triarylantimony Ar
3
Sb (Ar = 4-FC
6
H
4
, 3-MeC
6
H
4
) is oxidized by hydrogen peroxide to form tetranuclear complexes (4-FC
6
H
4
)
2
SbO
4
(O
2
)
2
and (3-MeC
6
H
4
)
2
SbO
4
(O
2
)
2
(as a DMSO ...solvate). The structure of the resulting compounds was examined by single crystal X-ray diffraction analysis.
•Phase equilibria of semiclathrate hydrate of methane in TBAB are investigated.•This study clarifies the discrepancy of published data in the literature and their reliability.•Two distinct ...equilibrium points for semiclathrate hydrates within pure hydrate stability zone are emphasized.•One closely corresponds to the pure methane hydrate phase stability curve.•Phase equilibria of semiclathrate hydrate of methane in TBAB+NaCl are investigated.
Phase equilibria of semiclathrate hydrates are important for their successful engineering applications due to more favorable process conditions compared to classical gas hydrate systems. Though sufficient information on the phase equilibria of semiclathrate hydrates of methane (CH4) in tetra-n-butyl ammonium bromide (TBAB) seems to be available, there are pronounced disagreements on the phase equilibrium data, particularly for 0.05 and 0.20 mass fraction (w) of TBAB. In this work, experimental studies are carried out to generate the equilibrium pressure (P) and temperature (T) for hydrates and semiclathrate hydrates of CH4 in an aqueous solution containing wTBAB=0.05 and 0.20 at P and T range of 1.02–13.73MPa and 281.63–294.54K, respectively. This study tries to clarify the discrepancy of published data in the literature and their reliability. Additionally, we present interesting insights into the phase behavior of semiclathrate hydrate of methane in TBAB based on the formation and dissociation curves observed in the experiments. It is observed that there existed two equilibrium points during the dissociation of semiclathrate hydrates of methane in TBAB; one closely corresponds to the pure methane hydrate phase stability curve and the second one to the semiclathrate hydrate system of methane. In addition phase equilibrium data is generated for the quaternary system of CH4+TBAB+H2O+NaCl for wNaCl=0.03 and 0.10 and wTBAB=0.05 and 0.20 in an aqueous solution at a P and T range of 1.65–20.71MPa and 281.19–296.38K, respectively. This is not yet available in the open literature. It is observed that NaCl inhibits the semiclathrate hydrate formation of CH4 in TBAB for wNaCl=0.03 and 0.10 in wTBAB=0.20 in the system. However, a promotion effect is observed for wNaCl=0.03 in wTBAB=0.05. This study calls for more detailed investigations on the effect of salts on semiclathrate hydrate systems, which may find potential use in engineering applications.
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Eleven antimicrobial peptides (AMP) based on the incorporation of cyclic tetra substituted Cα amino acids, as well as other unnatural amino acids were designed, synthesized and ...screened for in vitro activity against 18 strains of bacteria as well as 12 cancer cell lines. The AMPs discussed herein are derived from the following peptide sequence: Ac-GF(X)G(X)B(X)G(X)F(X)G(X)GB(X)BBBB-amide, X=any one of the following residues, A5c, A6c, Tic or Oic and B=any one of the following residues, Arg, Lys, Orn, Dpr or Dab. A diversity of in vitro inhibitory activity was observed for these AMPs. Several analogs exhibited single digit μM activity against drug resistant bacteria including; multiple drug resistant Mycobacterium tuberculosis, extremely drug resistant Mycobacterium tuberculosis and MRSA. The physicochemical properties of the basic amino acid residues incorporated into these AMPs seem to play a major role in defining antibacterial activity. Overall hydrophobicity seems to play a limited role in defining antibacterial activity. The ESKAPE pathogens were used to compare the activity of these AMPs to another family of synthetic AMPs incorporating the unnatural amino acids Tic and Oic. In most cases similarly substituted members of both families exhibited similar inhibitory activity against the ESKAPE pathogens. In specific cases differences in activity as high as 15 fold were observed between analogs. In addition four of these AMPs exhibited promising IC50 (<7.5μM) values against 12 different and diverse cancer cell lines. Five other AMPs exhibited promising IC50 (<7.5μM) values against selected cancer cell lines.
In recent years, various types of installations such as floating photovoltaic (PV) and agri-voltaic systems, and BIPV (building integrated photovoltaic system) have been implemented in PV systems ...and, accordingly, there is a growing demand for new PV designs and materials. In particular, in order to install a PV module in a building, it is important to reduce the weight of the module. The PV module in which low-iron, tempered glass is applied to the front surface, which is generally used, has excellent electrical output and reliability characteristics; however, it is heavy. In order to reduce the weight of the PV module, it is necessary to use a film or plastic-based material, as opposed to low-iron, tempered glass, on the front surface. However, if a material other than glass is used on the front of the PV module, various problems such as reduced electrical output and reduced reliability may occur. Therefore, in this paper, a PV module using a film instead of glass as the front surface was fabricated, and a characteristic analysis and reliability test were conducted. First, the transmittance and UV characteristics of each material were tested, and one-cell and 24-cell PV modules were fabricated and tested for electrical output and reliability. From the results, it was found that the transmittance and UV characteristics of the front material were excellent. In addition, the electrical output and reliability test results confirmed that the front-surface film was appropriate for use in a PV module.
The nuclear transport pathways of the photosensitizers
meso-tetra(4-sulfonatophenyl)porphyrin (TPPS
4) and
meso-tetra(4-N-methylpyridyl)porphyrin (TMPyP) during photosensitization and oxidative ...stress were characterized in CT-26 murine colon carcinoma cells using fluorescence microscopy and multi-pixel spectral imaging. Prior to irradiation, TPPS
4 and TMPyP localized mainly in the lysosomes, while irradiation or H
2O
2 treatment induced a relocalization into the nucleus and nucleoli. Flow cytometry analysis of isolated nuclei from the treated cells showed an increase in nuclear fluorescence accompanying the relocalization. Isolation and separation of the nuclear proteins according to molecular weight was performed using a sephadex G-100 column. The protein fractions exhibiting high fluorescence were separated by high performance liquid chromatography. Five major classes of proteins with a retention time of 1, 7, 11, 12 and 15 min were obtained. Each photosensitizer was associated with a distinct class of proteins. While TPPS
4 fluorescence was detected in the protein fraction with a retention time of 11 min, TMPyP fluorescence was associated with a protein fraction having a retention time of 7 min. We conclude that although oxidative stress triggers entry into the nucleus of both TPPS
4 and TMPyP, each sensitizer uses a distinct transport mechanism based on its chemical properties.
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