Synthesis and Characterization of Ln(III) Complexes and its Luminescence Properties.

Hexadentate ligand L and its Ln(3+) complexes EuLCl3 (1), TbLCl3 (2), SmLCl3 (3) are synthesised. All these complexes are well characterized for their photophysical properties such as luminescence lifetime decay(τ) and overall quantum yield(Φ). These complexes being water soluble, depicts their intense metal centred luminescence. Effect of pH on these complexes suggest that their emission intensities are stable in the pH range 4-9 and show their compatibility to function in the physiological pH. Graphical Abstract Normalized emisson spectra of complex 1, 2 and 3 (1x10(-5)M) in HEPES Buffer at pH 7.4 (λexc=276nm).

Identifying urban emission sources and their contribution to the oxidative potential of fine particulate matter (PM2.5) in Kuwait.

In this study, we investigated the seasonal variations, chemical composition, sources, and oxidative potential of ambient PM2.5 (particles with a diameter of less than 2.5 µm) in Kuwait City. The sampling campaign was conducted within the premises of Kuwait Institute for Scientific Research from June 2022 to May 2023, covering different seasons throughout the year. The personal cascade impactor sampler (PCIS) operated at flow rate of 9 L/min was employed to collect weekly PM2.5 samples on PTFE and quarts filters. These collected samples were analyzed for carbonaceous species (i.e., elemental and organic carbon), metals and transition elements, inorganic ions, and DTT (dithiothreitol) redox activity. Furthermore, principal component analysis (PCA) and multi-linear regression (MLR) were used to identify the predominant emission sources and their percentage contribution to the redox activity of PM2.5 in Kuwait. The results of this study highlighted that the annual-averaged ambient PM2.5 mass concentrations in Kuwait (59.9 µg/m3) substantially exceeded the World Health Organization (WHO) guideline of 10 µg/m3. Additionally, the summer season displayed the highest PM2.5 mass concentration (75.2 µg/m3) compared to other seasons, primarily due to frequent dust events exacerbated by high-speed winds. The PCA identified four primary PM2.5 sources: mineral dust, fossil fuel combustion, road traffic, and secondary aerosols. The mineral dust was found to be the predominant source, contributing 36.1% to the PM2.5 mass, followed by fossil fuel combustion and traffic emissions with contributions of 23.7% and 20.3%, respectively. The findings of MLR revealed that road traffic was the most significant contributor to PM2.5 oxidative potential, accounting for 47% of the total DTT activity. In conclusion, this comprehensive investigation provides essential insights into the sources and health implications of PM2.5 in Kuwait, underscoring the critical need for effective air quality management strategies to mitigate the impacts of particulate pollution in the region.

Inter-continental variability in the relationship of oxidative potential and cytotoxicity with PM2.5 mass.

Most fine ambient particulate matter (PM2.5)-based epidemiological models use globalized concentration-response (CR) functions assuming that the toxicity of PM2.5 is solely mass-dependent without considering its chemical composition. Although oxidative potential (OP) has emerged as an alternate metric of PM2.5 toxicity, the association between PM2.5 mass and OP on a large spatial extent has not been investigated. In this study, we evaluate this relationship using 385 PM2.5 samples collected from 14 different sites across 4 different continents and using 5 different OP (and cytotoxicity) endpoints. Our results show that the relationship between PM2.5 mass vs. OP (and cytotoxicity) is largely non-linear due to significant differences in the intrinsic toxicity, resulting from a spatially heterogeneous chemical composition of PM2.5. These results emphasize the need to develop localized CR functions incorporating other measures of PM2.5 properties (e.g., OP) to better predict the PM2.5-attributed health burdens.

The Impact of Russia-Ukraine geopolitical conflict on the air quality and toxicological properties of ambient PM2.5 in Milan, Italy.

The geopolitical conflict between Russia and Ukraine has disrupted Europe's natural gas supplies, driving up gas prices and leading to a shift towards biomass for residential heating during colder months. This study assessed the consequent air quality and toxicological impacts in Milan, Italy, focusing on fine particulate matter (PM2.5, dp < 2.5 µm) emissions. PM2.5 samples were analyzed for their chemical composition and assessed for their oxidative potential using the dithiothreitol (DTT) assay across three periods reflecting residential heating deployment (RHD): pre-RHD, intra-RHD, and post-RHD periods. During the intra-RHD period, PM2.5 levels were significantly higher than those in other periods, with concentrations reaching 57.94 ± 7.57 µg/m3, indicating a deterioration in air quality. Moreover, levoglucosan was 9.2 times higher during the intra-RHD period compared to the pre-RHD period, correlating with elevated levels of elemental carbon (EC) and polycyclic aromatic hydrocarbons (PAHs). These findings were compared with previous local studies before the conflict, underscoring a significant rise in biomass-related emissions. DTT assay levels during the intra-RHD were 2.1 times higher than those observed during the same period in 2022, strongly correlating with biomass burning emissions. Our findings highlight the necessity for policies to mitigate the indirect health effects of increased biomass burning emissions due to the energy crisis triggered by the geopolitical conflict.

Synthesis, structure and spectral investigation of hydrogen bonded helical chain in mixed ligand Cu(II) pyrimidone complex.

A simple mono-aqua-dichloro copper(II) pyrimidone complex has been synthesized and characterized using various spectral techniques such as Infrared and Raman in addition to the single crystal X-ray diffraction. The single crystal X-ray analysis carried out for the complex under study brings out the fact that there are two molecules in the unit cell with parameters a = 9.657(2); b = 3.857(2); c = 10.781(2); alpha = 90 degrees; beta = 107.781 degrees; gamma = 90 degrees; V = 382.891 and are crystallized in monoclinic crystal system with Pn space group. In solid state the molecules are interconnected through strong hydrogen bonding [O4...H21-O2W = 2.644 angstroms; O4...H21 = 1.853 angstroms; angleO4...H21-O2W = 172.87 degrees;] formed between the coordinated water molecule (O2W) and the exocyclic ketonic oxygen of the pyrimidone ring (O4). This H-bonding interaction causing a twist in the C1=O1...H21 segment [angleC1=O1...H21 = 122.29 degrees] in combination with weak pi-pi stacking interaction (3.857 angstroms) of the adjacent pyrimidone rings brings the single stranded helical chain which possesses both P and M sense of supramolecular helical assembly. The internal and external modes of vibrations of the crystal under study have been estimated and discussed by applying group theoretical methods.

Ophthalmic presentation of giant cell arteritis in African-Americans.

PurposeTo determine the differences in the presentation of ophthalmic giant cell arteritis between African-Americans and Caucasians.MethodsThis was a multicenter retrospective case series comparing African-American patients with ophthalmic GCA to a previously published Caucasian cohort. Neuro-ophthalmic centers across the United States were contacted to provide data on African-American patients with biopsy-proven ophthalmic giant cell arteritis. The differences between African-American and Caucasian patients with respect to multiple variables, including age, sex, systemic and ophthalmic signs and symptoms, ocular ischemic lesions, and laboratory results were studied.ResultsThe Caucasian cohort was slightly older (mean=76.1 years) than the African-American cohort (mean=72.6 years, P=0.03), and there was no difference in sex distribution between the two cohorts. Headache, neck pain, and anemia were more frequent, while jaw claudication was less frequent in African-Americans (P<0.01, <0.001, 0.02, and 0.03 respectively). Acute vision loss was the most common presentation of giant cell arteritis in both groups, though it was less common in African-Americans (78 vs 98% of Caucasians, P<0.001). Eye pain was more common in African-Americans (28 vs 8% of Caucasians, P<0.01).ConclusionsThe presenting features of ophthalmic giant cell arteritis in African-Americans and Caucasians are not markedly different, although a few significant differences exist, including higher rates of headache, neck pain, anemia, and eye pain, and lower rates of jaw claudication and acute vision loss in African-Americans. Persons presenting with suspicious signs and symptoms should undergo evaluation for giant cell arteritis regardless of race.

A theoretical study of the aqueous hydration of canonical B d(CGCGAATTCGCG): Monte Carlo simulation and comparison with crystallographic ordered water sites.

Monte Carlo computer simulation is described for the dodecamer d(CGCGAATTCGCG) together with 1777 water molecules at an environmental density of 1 gm/cc in a cubic cell under periodic boundary conditions. Water-water interactions were treated using the TIP4P potential and the solute water interactions by TIP4P spliced with the non-bonded interactions from the AMBER 3.0 force field. The stimulation was subjected to proximity analysis to obtain solute coordination numbers and pair interaction energies for each solute atom. Hydration density distributions partitioned into contributions from the major groove side, the minor groove side and the sugar-phosphate backbone were examined, and the probabilities of occurence for one- and two-water bridges in the simulation were enumerated. The results were compared with observations of crystallographic ordered water sites from x-ray diffraction studies on the native dodecamer by Dickerson and coworkers.

Theoretical account of the 'spine of hydration' in the minor groove of duplex d(CGCGAATTCGCG).

The hydration of B-form DNA involves a novel sequence of ordered water molecules in the minor groove known as the spine of hydration. The positions of the ordered waters in the AATT region have been determined and indicate water bridges between the A-N3 and T-O2 acceptor sites. Theoretical calculation on hydration based on Monte Carlo simulation show that the water bridges are more sensitive to the prescription for intermolecular potentials than the choice of canonical vs. crystallographic geometry. The GROMOS force field and the SPC model for water are shown to give an accurate theoretical account of the experimental data.

Synthesis and characterization of new chiral Cu(ii)-N4 complexes and their application in the asymmetric aza-Henry reaction.

Cu(ii) Schiff base complexes Cu(ii)- and Cu(ii)- based on 2-acetyl pyridine with both (1R,2R)-1,2-diaminocyclohexane and (1S,2S)-1,2-diaminocyclohexane were synthesized in a single step. Subsequent reduction of ligands and with NaBH4 followed by complexation with Cu(OTf)2 resulted in generation of two more additional chiral centers in complexes Cu(ii)- and Cu(ii)-. The ligands and their corresponding complexes were well characterized by several spectral techniques like (1)H-NMR, (13)C-NMR, LC-MS, CD, UV-Vis spectroscopy and microanalysis. The respective Cu(ii) complexes derived from ligands and were investigated using both the solution and solid state EPR spectra. The particular orientation of the reduced complex with Cu(OTf)2 was confirmed by the X-ray crystal structure of the corresponding complex. All the catalytic protocols were applied in the asymmetric aza-Henry reaction to evaluate the catalytic properties of the Cu(ii) complexes in the present study.

Cook detachable coil embolization of a symptomatic, isolated orbital arteriovenous fistula via a superior ophthalmic vein approach.

Isolated arteriovenous fistulas of the posterior orbit occur with exceptional rarity, and their evaluation and management are not well characterized. We describe the clinical presentation and treatment of a spontaneous arteriovenous fistula of the right posterior orbit via a superior ophthalmic vein approach for embolization using platinum detachable coils.

Replication timing properties of the human HPRT locus on active, inactive and reactivated X chromosomes.

X chromosome inactivation is associated with a highly asynchronous pattern of DNA replication at most X-linked loci in females. We studied the human HPRT locus, which is subject to X inactivation and expressed from only the active homolog, with the goal of comparing replication properties between the active and inactive homologs in this region using a fluorescence in situ hybridization approach. We found that in normal female lymphoblasts this locus is replicated in a highly asynchronous manner across a broad, discrete 500-600 kb zone with earliest replication appearing at the gene coding sequence. This general timing profile is maintained in normal male lymphoblasts, as well as in hamster x human hybrid cells containing the active human X chromosome. However, the inactive human X chromosome in the hamster cell background does not appear to function in a fully equivalent manner to the normal inactive X chromosome in female cells. Furthermore, reactivation of the inactive human X chromosome in a hamster x human hybrid system by 5-azacytidine treatment and HAT selection restores early replication at the HPRT gene itself, but does not change the overall domain behavior.

Synthesis, X-ray structure, single-crystal EPR and 1H NMR studies of a distorted square planar Cu(salEen)2(ClO4)2 complex in a novel bilayered architecture: salEen = N,N-diethylethylenesalicylidenamine.

Single-crystal X-ray structure and spectroscopic characterizations of Cu(salEen)2(ClO4)2, are reported; salEen is a Schiff base condensation product of equimolar amounts of salicylaldehyde and N,N-diethylethylenediamine. The complex crystallizes in a triclinic space group P1 with a = 12.055(4) A, b = 10.652(3) A, c = 12.701(3) A, alpha = 90.54(2) degrees, beta = 94.39(2) degrees, gamma = 91.35(3) degrees, and Z = 2. The coordination geometry around Cu(II) ion is tetrahedrally distorted square planar with salEen coordinating as a neutral bidentate ligand through N and O donor atoms (average Cu-N and Cu-O distances are 2.004 and 1.880 A, respectively). The counterion ClO4- makes H-bonding contacts with the neighboring cation moieties and forms a one-dimensional layered arrangement of the molecules. The pendent, N,N-diethylethylenediamine groups of salEen (from the centrosymmetrically related molecules) in adjacent layers interpenetrate, forming novel bilayered architectures, which are further held together by pi-pi stacking interactions. EPR studies on single crystals, in three mutually orthogonal planes, yield a rhombic g tensor (gx = 2.041(1), gy = 2.073(1), and gz = 2.220(1)) consistent with the distorted square planar geometry of the CuN2O2 moiety. The peak-to-peak line width of the EPR signal exhibits a |3 cos2 theta - 1|4/3 variation, attributable to one-dimensional magnetic exchange behavior of the complex. The analysis suggests that both the dipole-dipole and exchange interactions contribute to the line width. Interestingly, the complex is amenable for both EPR and NMR studies at ambient temperatures. The proton NMR signals are narrow in CD3CN solutions and the HOMO correlation spectroscopy (COSY) studies reveal the 1H connectivities. Nuclear spin lattice relaxation time (T1) measurements, using inversion recovery method, indicate that T1 values for all the protons are remarkably long compared to those of other mononuclear Cu(II) complexes.

Theoretical considerations on the "spine of hydration" in the minor groove of d(CGCGAATTCGCG).d(GCGCTTAAGCGC): Monte Carlo computer simulation.

A theoretical description of aqueous hydration in the minor groove of a B-form DNA is presented on the basis of a liquid-state Monte Carlo computer simulation on a system consisting of the oligonucleotide duplex d(CGCGAATTCGCG).d(GCGCTTAAGCGC) in a canonical B-form together with 1777 water molecules contained in a hexagonal prism cell and treated under periodic boundary conditions. The results are analyzed in terms of solvent density distributions. The calculated minor-groove solvent density shows considerable localization, indicative of discrete solvation sites and providing theoretical evidence for a well-defined ordered water structure. In the AATT sequence, this corresponds to the "spine of hydration" described by H. R. Drew and R. E. Dickerson [(1981) J. Mol. Biol. 151, 535-556] based on the x-ray crystal structure of the dodecamer hydrate. We find, however, that the calculated ordered water structure also extends into the CGCG flanking sequences, supported by the N2 hydrogen bond donors of the guanine residues and indicating that the spine of hydration could thus extend throughout the minor groove of a B-form DNA. This provides a possible explanation of the positive binding entropies observed by L. A. Marky and K. J. Breslauer [(1984) Proc. Natl. Acad. Sci. USA 84, 4359-4363] for both A.T and C.G sequences on the complexation of netropsin to the minor groove of DNAs. Implications of these results with regard to the thermodynamic stability of DNA in water and the sequence specificity of the minor groove hydration are discussed.

Large domains of apparent delayed replication timing associated with triplet repeat expansion at FRAXA and FRAXE.

Trinucleotide repeat expansions have been implicated in the causation of a number of neurodegenerative disorders. In the case of fragile X syndrome, full expansion of the FMR1 repeat element (CGG)n has also been correlated with replication timing delay of the locus and proximal flanking sequences in male lymphoblasts. To define more extensively this altered region of DNA replication, as well as to extend these studies to female cells containing premutant and mutant alleles, study of the replication timing properties of a >2-Mb zone in the FRAXA region (Xq27.3-q28) was undertaken by using a FISH technique. In this assay, relative times of replication of specific loci are inferred from the ratios of singlet and doublet hybridization signals in interphase nuclei. In all individuals with a full expansion of the trinucleotide repeat, a large (1-1.2-Mb) region of delayed timing was observed; the apparent timing of the earlier-replicating allele in female cells in this region was intermediate between normal and affected alleles in males, which is in accordance with expectations of a mixed population of cells resulting from random X inactivation. In addition, expansion of the nearby FRAXE locus also was found to correlate with replication timing delay, although the extent of the altered region was somewhat less. Trinucleotide repeat expansion thus may be acting in the Xq27.3-q28 region to alter long-range chromatin structure that could influence transcription of gene sequences within the affected domain.

Rapid mapping of Escherichia coli::Tn5 insertion mutations by REP-Tn5 PCR.

We describe a novel method to map chromosomal Escherichia coli::Tn5 insertion mutations rapidly. This method utilizes the ends of Tn5 and the E. coli REP sequence as primer binding sites for the polymerase chain reaction (PCR). The unique E. coli chromosomal sequence located between these primer binding sites is amplified by PCR and used as a probe to identify the recombinant clones from the Kohara phage ordered E. coli miniset bank that contains the Tn5 mutated loci. We used this approach to map two Tn5 insertion mutations previously identified by their effect on glycerol metabolism. The insertion mutations mapped to glpD, the aerobic sn-glycerol-3-phosphate dehydrogenase gene. Phenotypic analysis of the mutant strains revealed one with partial GlpD activity, suggesting transposon-mediated alteration of promoter activity. This mapping method should be applicable to the rapid physical mapping of any insertion mutation in the E. coli chromosome.

A Monte Carlo simulation study of the aqueous hydration of r(GpC)2: comparison with crystallographic ordered water sites.

Monte Carlo computer simulation is described for the dinucleotide duplex rGpC together with 562 water molecules at an environmental density of 1 g/cc in a cubic cell under periodic boundary conditions. Water-water interactions were treated using the TIP4P potential and the solute water interactions by TIP4P spliced with the nonbonded interactions from the AMBER 3.0 force field. The simulation was subjected to proximity analysis to obtain solute coordinate numbers and pair interaction energies for each solute atom. Hydration density distributions partitioned into contributions from the major groove side, the minor groove side and the sugar-phosphate backbone were examined, and the probabilities of occurrence for one- and two-water bridges in the simulation were enumerated. The results were compared with observations of crystallographic ordered water sites from x-ray diffraction studies on G and C containing small molecules, and in crystal structure determinations of the sodium, calcium, and ammonium salts of rGpC. The calculated results are generally consistent with the observed sites, except for cytosine N4, where a hydration site is predicted yet none observed in rGpC salts, and for guanine N3, which appears in this calculation to compete unfavorably with the adjacent donor site at guanine N2. There is, however, a significant probability of finding a one-water G-N3-W-G-N2 bridge indicated in the simulation. An explanation for the guanine N3 discrepancy in terms of electrostatic potentials is also offered. The calculated one- and two-water bridges in the rGpC hydration complex coincide in a number of cases to those observed in the ordered water structure of the sodium rGpC crystal hydrate.