Cord Blood Cortisol Level - A Possible Predictor for Respiratory Distress Syndrome in Preterm Neonates.

BACKGROUND: Respiratory Distress Syndrome (RDS) is a leading cause of death in premature infants. There are different clinical/ biochemical markers associated with the RDS. One of the potential biochemical markers is cortisol in cord blood. PURPOSE: This study aims to correlate cortisol levels in preterm neonates with RDS and to establish whether cord blood cortisol is a reliable predictor for RDS. MATERIALS AND METHODS: This prospective analytical study was conducted in a tertiary care hospital over nine months among fifty preterm neonates. Data were collected using proforma, and cord blood was collected at the time of delivery. Cortisol levels were compared and correlated to the development of RDS. RESULTS AND DISCUSSION: The mean ± SD cord blood cortisol level among preterm neonates was 5.97 ± 2.74 (SD) µg/dl. The levels were higher in neonates whose mothers received antenatal steroids and were significantly lower (2.86 ± 1.66 µg/dl) in those who developed RDS. Association between cord blood cortisol level and RDS was found with an odds ratio of 57.4, which was statistically significant. The percentage of babies developing RDS in mothers not covered with antenatal steroids was significantly higher than those covered (p-value is 0.000). The mean cord blood cortisol levels were exceptionally low (1.89 µg/dl) in neonates who expired compared to those who survived (7.02 µg/dl). CONCLUSION: There is an association between cord blood cortisol levels and RDS. Hence, Cord blood cortisol levels may be used to predict RDS and help initiate early treatment, thus preventing mortality and morbidity.

Computational Study on the Effect of Thienyl π-Donor on the Optical Response of Nonclassical Oligo-Pyrazinothienothiadiazole Biradicaloids.

Computational analyses were performed on nitrogen-rich oligothiadizolothiophenes TTn (n = 0-3) and their four π-donor-substituted derivatives Th-TTn (n = 0-3) to examine the optical response due to geometrical and electronic structural attributes in the longitudinal and transverse axes, respectively. Our results are understood in the context of greater conjugation in the longitudinal axis (via additional fused rings) and substitution of a thienyl π-donor in the transverse axis of the geometry of each derivative. On inspection of the frontier molecular orbitals, we found that the better electron-accepting ability with minimal sacrifice in the ionization potentials results from geometrical aspects in both longitudinal and transverse axes. Due to the narrowed highest occupied molecular orbital-lowest unoccupied molecular orbital gaps, all of the derivatives exhibit a biradicaloid character (BRC) and one-photon panchromatic absorption; however, the open-shell nature weakened the charge transfer characteristics of excitation. In both the series, the odd electron density distributions and electron localization plots amply demonstrate the weakening of ylide character in fused thiophene rings and clearly indicate to the emergence of a long-bond/single BRC in the sulfurdimithide moiety in both series. In addition, the estimated tensor components of the second hyperpolarizability as well as overall responses confirm the shift from the longitudinal to transverse axis following the substitution with the π-donor. Interestingly, the TPA cross sections show comparable behavior, but contrary to γ, π-donor thienyl substitution appears to be discouraging in getting higher TPA responses for higher homologous series. Therefore, this study opens a new conjecture on tuning better nonlinear optical properties of organic functional materials.

Revealing the biradicaloid nature inherited in the derivatives of thieno[3,4-c][1,2,5]thiadiazole: a computational study.

Computational studies were performed on non-classical thieno[3,4-c][1,2,5] thiadiazole and its pi donor derivatives (TT dyes) so as to delineate the factors responsible for their near-infrared (NIR) absorption. For all dyes except the unsubstituted bare dye, adiabatic singlet-triplet energy gaps (estimated through the ΔSCF procedure using the B3LYP and M062X DFT methods and SFTDDFT with the 5050 functional) were less than 1eV. Percentage calculations of the biradicaloid character suggested a moderate biradicaloid nature in all derivatives. There was a resemblance between the frontier molecular orbital (MO) picture of the TT bicyclic ring and the degenerate non-bonding molecular orbitals of Trimethyleneethane (TME, a known biradical). Inter-fragment charge transfer analysis revealed not only a considerable donation of charge to the central ring (Acceptor, TT part) but also substantial charge redistribution within the ring itself. From these results, it was inferred that NIR absorption, in these dyes, was due to: (1) a reduced HOMO-LUMO gap (HLG) as a TME biradical substructure forms its chromophoric part; and (2) charge transfer from the donor substituents. The non-bonding nature of the S atom, in the bare dye, with its neighbouring N/C atom (of the highest occupied π-MOs), led to an examination of its electronic structure using the ab initio valence bond method. The relatively large weight and energetic stability of the biradicaloid VB structures compared to those of the ylidic structures clearly disclosed the importance of biradicaloid structures in the overall resonance of the bare dye. Their utility as singlet fission materials was screened using singlet and triplet energy-based molecular structure activity criteria. The results were encouraging, demanding experiments to reaffirm the materials' usefulness.

Infected Mosquitoes Have Altered Behavior to Repellents: A Systematic Review and Meta-analysis.

Here we conducted a systematic review and meta-analysis to reach a consensus on whether infected and uninfected mosquitoes respond differently to repellents. After screening 2,316 published studies, theses, and conference abstracts, we identified 18 studies that tested whether infection status modulated the effectiveness of repellents. Thirteen of these studies had outcomes available for meta-analysis, and overall, seven repellents were tested (typically DEET with 62% of outcomes), six mosquito species had repellence behaviors measured (typically Aedes aegypti (L.) (Diptera: Culicidae) mosquitoes with 71% of outcomes), and a broad diversity of infections were tested including Sindbis virus (Togaviridae: Alphavirus) (33% of outcomes), Dengue (Flaviviridae: Flavivirus) (31%), malaria (Plasmodium berghei Vincke & Lips (Haemospororida: Plasmodiidae) or P. falciparum Welch (Haemospororida: Plasmodiidae); 25%), Zika (Flaviviridae: Flavivirus) (7%), and microsporidia (4%). Pooling all outcomes with meta-analysis, we found that repellents were less effective against infected mosquitoes-marking an average 62% reduction in protective efficacy relative to uninfected mosquitoes (pooled odds ratio = 0.38, 95% confidence interval = 0.22-0.66; k = 96). Older infected mosquitoes were also more likely to show altered responses and loss of sensitivity to repellents, emphasizing the challenge of distinguishing between age or incubation period effects. Plasmodium- or Dengue-infected mosquitoes also did not show altered responses to repellents; however, Dengue-mosquito systems used inoculation practices that can introduce variability in repellency responses. Given our findings that repellents offer less protection against infected mosquitoes and that these vectors are the most dangerous in terms of disease transmission, then trials on repellent effectiveness should incorporate infected mosquitoes to improve predictability in blocking vector-human contact.

Experimental and theoretical insights on the effect of solvent polarity on the photophysical properties of a benzanthrone dye.

Benzanthrone derivatives show interesting solvent dependent photophysical properties. Understanding of their photophysical properties is essential for developing the fluorescence probes based on benzanthrone derivatives. The photophysical properties of 3-(N'-chlorophenyl)piperazino-7H-benzo[de]anthracen-7-one [ClPh-PBA] molecule are reported in different solvents and solvent mixtures. The change in Stokes shift, quantum yield, fluorescence life time and radiative rate constants as a function of solvent polarity shows that the Intermolecular Charge Transfer (ICT) is affected by solvent polarity and hydrogen bonding. The quantum yield and fluorescence life time values decrease and the nonradiative decay rate constant (knr) values are observed to be higher in polar solvents. The weak emission of ClPh-PBA in polar solvents is primarily due to the non-radiative torsional motion of the chlorophenyl group around benzanthrone moiety. The torsional motion of chlorophenyl group at the remote nitrogen around benzanthrone moiety is also evident from TDDFT calculations performed using B3LYP/6-311+ G (d, p) basis set. The ground state and excited state dipole moments, absorption and emission maxima (nm) along with other quantum chemical parameters are obtained using B3LYP/6-311+ G (d, p) basis set. The experimental and theoretical results follow the similar trends.

Solvatochromic study of 3-N-(N'-methylacetamidino)benzanthrone and its interaction with dopamine by the fluorescence quenching mechanism.

The change in photophysical properties of the organic molecule due to solvatochromic effect caused by different solvent environments at room temperature gives information about the dipole moments of 3-N-(N'-methylacetamidino)benzanthrone (3-MAB). The quantum yield, fluorescence lifetime of 3-MAB was measured in different solvents to calculate radiative and non-radiative rate constants. The results revealed that the excited state dipole moment (µe ) is relatively larger compared to the ground state dipole moment (µg ), indicating the excited state of the dye under study is more polar than the ground state and the same trend is noticed with theoretical calculations performed using the CAM-B3LYP/6-311+G(d,p) method. Further, the study on preferential solvation was carried out for 3-MAB dye in ethyl acetate-methanol solvent mixture. The fluorescence quenching method has been employed for the detection of dopamine using 3-MAB as fluorescent probe, using steady-state and time resolved methods at room temperature. The method enables dopamine in the micro molar range to be detected. Also, an attempt to verify the quenching process by employing different models has been tried. Various rate parameters are measured using these models, our results indicates the quenching process is diffusion limited.

A combined spectroscopic and TDDFT investigation of the solute-solvent interactions of two coumarin derivatives.

The UV/Vis absorption and fluorescence characteristics of 3-cyano-7-hydroxycoumarin [CHC] and 7-amino-4-methyl-3-coumarinylacetic acid [AMCA-H] were studied at room temperature in several neat solvents and binary solvent mixtures of 1,4-dioxane/acetonitrile. The effects of solvent on the spectral properties are analyzed using single and multi-parameter solvent polarity scales. Both general solute/solvent interactions and hydrogen bond interactions are operative in these systems. The solvation of CHC and AMCA-H dyes in 1,4-dioxane/acetonitrile solvent mixtures has been studied. The solutes CHC and AMCA-H are preferentially solvated by acetonitrile and a synergistic effect is observed for both molecules in dioxane/acetonitrile solvent mixtures. In addition, using the solvatochromic method the ground- and the excited-state dipole moments of both the dyes were calculated. The ground- and excited-state dipole moments, absorption and emission maxima and HOMO-LUMO gap were also estimated theoretically using B3LYP/6-311+ G (d,p) level of theory in the gaseous phase, dioxane and acetonitrile solvents. Furthermore, changes in dipole moment values were also calculated using the variation of Stokes shift with the molecular-microscopic empirical solvent polarity parameter ( ETN). The observed excited-state dipole moments are larger than their ground-state counterparts, indicating a substantial redistribution of the electron densities in a more dipolar excited state for both coumarins investigated.

First Degree Heart Block with Multi-focal Atrial Ectopics in an Adolescent Girl Due to Hypomagnesemia.

Nutritional deficiencies are common in adolescent children and include deficiencies of both micro- and macronutrients. Magnesium is an important mineral that is essential for maintenance of numerous electrophysiological and biochemical processes in the body. We report an adolescent girl who developed an episode of syncope with first degree heart block on electrocardiography and run of multifocal atrial ectopics on 24 h holter monitoring. Serum magnesium was found to be low with decreased urinary magnesium excretion. There were no other electrolyte abnormalities. Structural heart disease was ruled out by a normal echocardiogram. The rhythm changes were attributable to nutritional hypomagnesemia and were promptly reversed on correcting the hypomagnesemia.

Comparative study of the semiconducting properties of benzothiadiazole and benzobis(thiadiazole) derivatives using computational techniques.

Recent literature reports indicate that derivatives of benzothiadiazole (BT) and benzobis(thiadiazole) (BBT), which differs from BT by an extra thiadiazole ring, exhibit good semiconducting properties, such as high electron mobility and low-lying lowest unoccupied molecular-orbital (LUMO) levels. In this study herein, computational techniques like density functional theory (DFT), spin-flip DFT and valence-bond methods are used to analyze the semiconducting properties of these molecules. Calculations at the B3LYP/cc-pVTZ level reveal that all the BBT molecules, including the bare BBT ring, have lower lying LUMO energies (3.70-4.11 eV) compared to the BT derivatives (2.56-3.41 eV) with similar substitution. The reorganization energies (λ(+)/λ(-)) obtained at this level of theory of the BT derivatives are around (225-333)/(246-315) meV, while BBT derivatives have much smaller reorganization energies and these are in the range of (129-259)/(150-230) meV. We observe that the different behavior of BBT is due to the inherited biradicaloid character from the parent molecule tetramethylenebenzene (TMB), a disjoint non-Kekule biradical having non-bonding molecular orbitals (NBMOs) as the highest occupied molecular orbital (HOMO) and LUMO. Additionally, the perturbation of the orbitals of the biradical TMB to obtain BBT is the major cause for the BBT derivatives to have a larger electron affinity (EA) and a smaller HOMO-LUMO gap (HLG) compared to BT derivatives.

Substituents destabilize the molecule by increasing biradicaloid character and stabilize by intramolecular charge transfer in the derivatives of benzobis(thiadiazole) and thiadiazolothienopyrazine: a computational study.

Keeping in view the possible applications of singlet open-shell molecules as semiconductors, non-classical derivatives of the heterocyclic rings benzobis(thiadiazole) (BBT) and its positional isomer thiadiazolothienopyrazine (TTP) are characterized using DFT methodologies. M06-2X, B3LYP and BHandHLYP functionals were used to optimize the geometries and estimate the vertical transition energies. It is observed that unlike the BHandHLYP functional (50% exchange), which gives rise to spin-contaminated solutions for all molecules in the series, M06-2X (54% exchange) affords a wavefunction either with no instability or negligible instability for most of the molecules. The results are compared with the earlier reported experimental data and those obtained herein using the spin-flip (SF)-5050 method. It is found that B3LYP does not fare well while on the other hand the M06-2X and SF-50-50 are in good agreement with the experimental results. It is seen that M06-2X TD-DFT for the molecules can be carried out without major spin contamination and also that the more time-consuming CI can be avoided for the calculation of transition energies. The biradical nature of the molecules is estimated by the singlet-triplet gap. Intramolecular charge transfer is calculated. It is found that the ring substituents donate charge in the ground state, creating a zwitterionic structure. Thus the substituents play an interesting dual role, decreasing the stability of the molecule by increasing the biradical character (small HOMO-LUMO gap), and stabilization of this ground state by intramolecular charge transfer.