TDDFT versus GW/BSE Methods for Prediction of Light Absorption and Emission in a TADF Emitter

Design concepts for organic light emitting diode (OLED) emitters, which exhibit thermally activated delayed fluorescence (TADF) and thereby achieve quantum yields exceeding 25%, depend on singlet-triplet splitting energies of order kT to allow reverse intersystem crossing at ambient temperatures. Simulation methods for these systems must be able to treat relatively large organic molecules, as well as predict their excited state energies, transition energies, singlet-triplet splittings, and absorption and emission cross sections with reasonable accuracy, in order to prove useful in the design process. Here we compare predictions of TDDFT with M06-2X and ωB97X-D exchange-correlation functionals and a G_oW_o@HF/BSE method for these quantities in the well-studied DPTZ-DBTO2 TADF emitter molecule. Geometry optimization is performed for ground state (GS) and lowest donor-acceptor charge transfer (CT) state for each functional. Optical absorption and emission cross sections and energies are calculated at these geometries. Relaxation energies are on the order of 0.5 eV, and the importance of obtaining excited state equilibrium geometries in predicting delayed fluorescence is demonstrated. There are clear trends in predictions of G_oW_o@HF/BSE, and TDDFT/ωB97X-D and M06-2X methods in which the former method favors local exciton (LE) states while the latter favors DA CT states and ωB97X-D makes intermediate predictions. G_oW_o@HF/BSE suffers from triplet instability for LE states but not CT states relevant for TADF. Shifts in HOMO and LUMO levels on adding a conductor-like polarizable continuum model dielectric background are used to estimate changes in excitation energies on going from the gas phase to a solvated molecule.

High-flow nasal cannula versus non-invasive ventilation for acute hypercapnic respiratory failure in adults: a systematic review and meta-analysis of randomized trials

Background

Non-invasive ventilation (NIV) with bi-level positive pressure ventilation is a first-line intervention for selected patients with acute hypercapnic respiratory failure. Compared to conventional oxygen therapy, NIV may reduce endotracheal intubation, death, and intensive care unit length of stay (LOS), but its use is often limited by patient tolerance and treatment failure. High-flow nasal cannula (HFNC) is a potential alternative treatment in this patient population and may be better tolerated.

Research question

For patients presenting with acute hypercapnic respiratory failure, is HFNC an effective alternative to NIV in reducing the need for intubation?

Methods

We searched EMBASE, MEDLINE, and the Cochrane library from database inception through to October 2021 for randomized clinical trials (RCT) of adults with acute hypercapnic respiratory failure assigned to receive HFNC or NIV. The Cochrane risk-of-bias tool for randomized trials was used to assess risk of bias. We calculated pooled relative risks (RR) for dichotomous outcomes and mean differences (MD) for continuous outcomes, with corresponding 95% confidence intervals (CI) using a random-effects model.

Results

We included eight RCTs (n = 528) in the final analysis. The use of HFNC compared to NIV did not reduce the risk of our primary outcome of mortality (RR 0.86, 95% CI 0.48–1.56, low certainty), or our secondary outcomes including endotracheal intubation (RR 0.80, 95% CI 0.46–1.39, low certainty), or hospital LOS (MD − 0.82 days, 95% CI − 1.83–0.20, high certainty). There was no difference in change in partial pressure of carbon dioxide between groups (MD − 1.87 mmHg, 95% CI − 5.34–1.60, moderate certainty).

Interpretation

The current body of evidence is limited in determining whether HFNC may be either superior, inferior, or equivalent to NIV for patients with acute hypercapnic respiratory failure given imprecision and study heterogeneity. Further studies are needed to better understand the effect of HFNC on this population.

Assessing the clinical significance of echocardiograms in determining treatment of patent ductus arteriosus in neonates

BACKGROUND

To evaluate the utility of echocardiogram (ECHO) in detection and treatment of patent ductus arteriosus (PDA) and hemodynamically significant PDA (hsPDA) in preterm neonates.

METHODS

This was a retrospective case-control study of all preterm infants born or admitted to the level III Neonatal Intensive Care Unit in McMaster Children's Hospital from January 2009 to January 2013. These cases were further classified into the following sub-groups: group A) hsPDA confirmed on ECHO; and the control, group B) PDA (but not hemodynamically significant) confirmed on ECHO. Patients without an ECHO were excluded from all analyses. The primary outcome was incidence of treatment for PDA.

RESULTS

PDA treatment was administered in 83.3% and 11.2% of patients in groups A and B respectively (P < 0.05). Among patients with a hsPDA within group A, 17% did not receive treatment, while 11% of patients with non-hemodynamically significant PDA received treatment for the PDA. Within the cohort of patients who received treatment for a hsPDA, gestational age below 35 weeks as well as murmurs heard on auscultation were both found to be predictors of treatment.

CONCLUSION

While the ECHO remains the gold standard for detecting pathological PDA, there is evidence that other traditional clinical measures continue to guide clinical practice and treatment decisions. Further research is required to gain an understanding of how clinical measures and ECHO may be used in conjunction to optimize resource utilization.

A natural flavonoid, apigenin isolated from Clerodendrum viscosum leaves, induces G2/M phase cell cycle arrest and apoptosis in MCF-7 cells through the regulation of p53 and caspase-cascade pathway

BACKGROUND

With 9.6 million deaths in 2018, cancer remains the second leading cause of death worldwide. Breast cancer is the most deadly type of cancer among females, with 55.2% of crude incidence rate and 16.6% of crude mortality rate.

PURPOSE

The present study was aimed to investigate the anti-breast cancer potential of natural dietary flavonoid, apigenin isolated from Clerodendrum viscosum leaves.

METHODS

Apigenin was evaluated for in-depth anticancer activity in MCF-7 cells using cell viability assay, cell cycle analysis, Annexin-V-FLUOS staining, ROS induction, morphological analysis, and western blot analysis.

RESULTS

Apigenin showed selective cytotoxicity on MCF-7 cells with an IC₅₀-56.72 ± 2.35 µM, while negligible cytotoxicity was observed on WI-38 cells. Further, the flow cytometer-based analysis showed that apigenin halted MCF-7 cells in the G2/M phase arrest followed by dose-dependent apoptosis. Moreover, the FACS and confocal microscopy results confirmed the elevation of intracellular ROS and nuclear fragmentation in apigenin-treated MCF-7 cells. Western blots showed up-regulation of cell cycle regulatory proteins, increased p53 expression, Bax/Bcl-2 ratio, activation of caspases, and cleavage of PARP. Finally, apigenin treatment in the presence of Pifithrin-µ showed decreased apoptotic population and it was further confirmed through western blotting study. The results revealed the vital role of p53 in apigenin-induced apoptosis in MCF-7 cells.

CONCLUSIONS

In the present findings, treatment of apigenin-induced intracellular ROS in MCF-7 cells followed by induction of G2/M phase cell cycle arrest and further apoptosis through the regulation of p53 and caspase-cascade signaling pathway.

Reduction of plasma aldosterone and arterial stiffness in obese pre- and stage1 hypertensive subjects after aerobic exercise

Obesity-related hypertension is associated with increased activity of the renin-angiotensin-aldosterone system (RAAS), increasing arterial stiffness. Aerobic exercise decreases pulse wave velocity (PWV), therefore a treatment option for hypertension and obesity. Assess RAAS activity and PWV before and after 4 weeks of aerobic training in unmedicated, pre-to-stage-1 hypertensives. Ten obese subjects (52±3.2 years, body mass index=33.5±1.4) performed 30 min of aerobic exercise on a treadmill 3 days per week at 65% of peak oxygen consumption (VO2peak). Descriptive characteristics, systolic and diastolic blood pressure (SBP and DBP), PWV, and a blood draw was performed at baseline, following the 4-week control and training interventions. No differences in descriptive characteristics during the control period were observed, however, a significant decrease in plasma aldosterone (ALDO) (255.4±75 to 215.8±66 pg ml(-1), P=0.001), SBP (140±12 to 136±10.4 mm Hg; P=0.02), DBP (89±4.2 to 85±6.3 mm Hg; P=0.03) and central PWV (11.2±0.6 to 9.8±0.8 m s(-1); P=0.04) was shown pre-to-post exercise training. Four weeks of moderate-intensity aerobic training in obese, hypertensives decreases plasma ALDO independently of body weight and is significantly correlated to decreases in PWV reductions.

Inheritance of plumage colour variations in a large flock of Japanese quail

1. The inheritance of various plumage colour variants and their underlying interactions were investigated in a large flock of Japanese quail maintained at CARI (India) by conducting reciprocal crosses between four breeding stocks inheriting Pharaoh, White Breasted, White and Brown plumages, followed by test crosses. 2. Based on the proportion of plumage-colour types in the progeny, putative genotypes were determined for parents and offspring for each of the crosses. 3. The White and Brown phenotypes were attributed to the Panda (S) and Roux (Br) loci respectively in agreement with contemporary quail stocks. 4. The White Breasted plumage type present in our stock was caused by a novel mutation with dominant gene action at an autosomal locus that was not allelic to either Panda or the White feather locus. 5. A recessive epistatic action of the Panda locus (S) on White Breasted (Wb) resulted in a White colour phenotype. 6. A novel phenotype, White Breasted-Brown was co-expressed with the Br and Wb loci. 7. It was concluded that breeding for customized feather colour phenotypes in Japanese quail using colour mutations was feasible and would be advantageous in order to overcome the limitations of legislation to protect wildlife in India.

Genotypic diversity in species of Scilla

Two cytotypes of Scilla indica and three other species, namely S. nervosa, S. siberica and S. vindobonensis were investigated. The estimation of nuclear DNA content was utilized as a measure of genetic diversity at inter- and intraspecific levels and as an index of the trends of evolution. S. siberica with a very high DNA value was regarded as indicative of a primitive state. The heavy intraspecific difference in DNA content in S. indica has been attributed to amplification of the DNA.

Application of an MTT reduction assay for assessing sperm quality and predicting fertilising ability of domestic fowl semen

1. The ability of domestic fowl spermatozoa to reduce MTT tetrazolium to its coloured formazan was compared with other tests of sperm quality and fertilising ability. 2. MTT reduction was highly correlated with sperm ATP content (r2 = 0.85); sperm mobility (r2 = 0.62.); sperm:perivitelline layer interaction (r2 = 0.80) and fertilizing ability (r2 = 0.83). 3. The simple, robust, MTT-reduction assay may therefore be used to select male chickens on the basis of their sperm quality and thus potential fertilising ability.

Primary osteogenic sarcoma of the tongue

A 56-year-old man presented with the difficulty of swallowing and respiratory distress due to a large tumour arising from the tongue and occupying the entire oral cavity. Histological examination revealed it to be an extraskeletal osteogenic sarcoma. The tumour was excised. After six weeks, he came back with massive local recurrence and bleeding from the tumour, but died despite chemotherapy. Review of the literature revealed only four other such cases of this rare tumour. A brief review of these four cases is also made.

Ortner's syndrome revisited

Hoarseness of voice due to paralysis of the left recurrent laryngeal nerve caused by a dilated left atrium in mitral stenosis as discussed by Ortner, is a subject of controversy. Different authors have cited different mechanisms as explanation. A variety of cardiac problems such as primary pulmonary hypertension, ischaemic heart disease, various congenital heart disorders can all lead to paralysis of the left recurrent laryngeal nerve. Most authors believe that pressure in the pulmonary artery causes the nerve compression. In Papua New Guinea cor pulmonale and rheumatic heart disease are the commonest cardiac disorders seen. Ortner's syndrome is a rarity and has never been reported from here before. Here three different case reports are presented with mitral stenosis, primary pulmonary hypertension and combined mitral stenosis and regurgitation and the pathogenesis of hoarseness is discussed.

Recurrence of kala-azar after PKDL: role of co-factors

Recurrence of kala-azar after post kala-azar dermal leishmaniasis (PKDL) has remained uncommon. We report here two patients with recurrence of kala-azar (KA) after development of PKDL. In one case the second attack of KA was preceded by repeated attacks of malaria and tuberculosis, and in the other the recurrence of KA followed an attack of measles. While measles has earlier been suggested as co-factor in inducing transformation from sub-clinical to clinical kala-azar, malaria was demonstrated to enhance the virulence and invasiveness of Leishmania in an experimental model as well as under natural condition. We propose that in our cases, measles and repeated attacks of malaria or tuberculosis led to immunosuppression and recurrence of visceral leishmaniasis (VL).

Interactions of alpha-lactalbumin with fatty acids and spin label analogs

Bovine alpha-lactalbumin (alpha-LA) has been shown by intrinsic protein fluorescence and electron spin resonance methods to interact with the spin-labeled fatty acid analog, 5-doxylstearic acid, as well as stearic acid. An intrinsic fluorescence titration of various alpha-LA forms with 5-doxylstearic acid causes first an increase and then a decrease in emission intensity with concomitant shifts in tryptophan emission wavelength. In some cases, up to three steps in the fluorescence titration curves were visible, which were fit to apparent binding steps from 10(-6) to 10(-4) M. The binding parameters of 5-doxylstearic acid for apo- and Ca2+-alpha-LA were an order of magnitude different from one another; the stronger one, apo-alpha-lactalbumin, exhibited a Kd of 35 microM. Electron spin resonance titrations of 5-doxylstearic acid-loaded apo-alpha-LA with stearate (micelles) seem to suggest separate binding loci if alpha-LA indeed binds stearate at these concentrations. The titration of alpha-LA by stearic acid results in a fluorescence emission red shift and an apparent stepped increase in fluorescence intensity. Lipid-protein association occurred at concentrations at which stearic acid micelles and aggregates begin to form in the absence of protein. Nonetheless, the relatively strong association between stearic acid and apo-alpha-LA was also confirmed by means of the fluorescent indicator acrylodated fatty acid binding protein, in which addition of alpha-LA to the stearate-loaded indicator protein reverses the decrease in fluorescence of the acrylodan chromophore conjugated to the protein.

Characterization of lanthanide ion binding to the EF-hand protein S100 beta by luminescence spectroscopy

S100 beta is a member of a group of low-molecular weight acidic calcium binding proteins widely distributed in the vertebrate nervous system containing two helix-loop-helix calcium binding motifs (sites I and II). In addition, S100 beta also has auxiliary Zn2+ binding sites that are distinct from the Ca2+ binding sites. Luminescence spectroscopy using Eu3+ and Tb3+ as spectroscopic probes for Ca2+ is used to characterize the Ca2+ binding sites of this protein. Eu3+-bound S100 beta shows two distinct Eu3+ binding environments from both the excitation spectrum and Eu3+ excited state lifetimes. Eu3+ bound to the classical EF hand site II has a Kd of 660 +/- 20 nM, whereas the dissociation constant for the pseudo-EF hand site I is significantly weaker. Lifetimes in H2O and D2O lead to the finding that there are four water molecules coordinated to the Eu3+ in the weakly binding site I and two water molecules to the tightly binding site II. Site II in S100 beta expectedly is very similar to high-affinity Ln3+ binding domains I and II in calmodulin. Eu3+ luminescence experiments with Zn2+-loaded S100 beta show that the lifetime for Eu3+ in site I in Zn2+-loaded S100 beta is significantly different than that in the absence of Zn2+. Tyrosine-17-sensitized Tb3+ luminescence experiments indicate that the Tb3+ occupying the proximal weaker binding site I is sensitized, whereas Tb3+ in site II is not. The distance between sites I and II (15.0 +/- 0.4 A) in S100 beta was determined from Forster-type energy transfer in D2O solutions containing bound Eu3+ donor and Nd3+ acceptor ions. For Zn2+-S100 beta, the intersite distance is reduced to 13 +/- 0.3 A. Location of histidine-15 close to pseudo-EF site I suggests that Zn2+ binding likely changes the conformation of this site, causing a reduction of the intersite distance by approximately 2 A.

Predicting the fertilising ability of avian semen: the development of an objective colourimetric method for assessing the metabolic activity of fowl spermatozoa

1. A simple, objective colourimetric technique for estimating the capacity of fowl spermatozoa to reduce a tetrazolium dye is described. 2. The test is shown to give a quantitative measurement of the metabolic activity of spermatozoa, as judged by their rate of oxygen utilisation, and thus of the 'quality' of semen in poultry.

Predicting the fertilising ability of avian semen: comparison of a simple colourimetric test with other methods for predicting the fertilising ability of fowl semen

1. The rate of tetrazolium dye-reduction by fowl spermatozoa measured by an objective colourimetric assay was shown to correlate strongly with sperm motility, morphology, ATP content and fertilising ability. 2. Although dye-reduction appeared less well correlated with fertilising ability than the other variables, the method for its determination has many practical advantages for the assessment of semen quality in poultry.

Action of polyamines on ribonucleic acid and protein synthesis during ontogeny of human fetal liver

A higher rate of RNA synthesis in human fetal liver cells was found during the early age of gestation, after a drop, it gradually increases to a maximum value between 18 and 22 weeks, followed by a sharp decrease at later period of gestation. Total polyamine content of fetal liver tissue shows a similar trend. However, when liver cell suspension was incubated with exogenous spermine, spermidine and putrescine there is a dose-dependent inhibition in RNA synthesis. Protein synthesis in human fetal liver cells was stimulated with lower doses of spermine, spermidine and putrescine and inhibited at higher doses. The optimum dose for stimulation and the degree of stimulation was, however, not the same for fetuses of different gestational ages.

Ontogeny of polyamines in relation to nucleic acids in brain and spinal cord of the developing human fetus

The polyamines, spermine and spermidine, and the diamine, putrescine, were estimated in relation to the distribution of RNA and DNA in cerebral cortex, cerebellum and spinal cord of the human CNS during prenatal development. Polyamines were found to be maximally located in the spinal cord, minimum being in cerebellum. Relation between polyamines and nucleic acids was region specific.

Occurrence of phosphodiesterase IV in the developing human brain, liver and placenta

The presence of phosphodiesterase IV has been demonstrated in the human fetal brain, liver and placenta as early as in the 6th week of intrauterine development. The enzyme activity in each tissue increases with gestation, being maximum at 18-21 wk and then decreases. The Km values of this enzyme for bis-(p-nitrophenyl)-phosphate hydrolysis in the brain, liver and placenta are 2.94 mM, 1.47 mM and 1.66 mM, respectively. Presence of sulfhydryl group in the active center of the placental enzyme has been demonstrated with the help of cationic study. EDTA inhibits the enzyme in all three tissues. Effect of concanavalin A reveals the absence or unexposition of glucose, mannose and N-acetylglucosamine moieties in the active site of the enzyme in each of the three tissues. Maximum enzyme activity has been found to be localized in the soluble supernatant fraction obtained on centrifuging the brain and liver homogenate at 105,000 x g and in 20,000 x g pellet of the placenta.