Charge Transport and Optical Absorption Properties of Dibenzocoronene Tetracarboxdiimide Based Liquid Crystalline Molecules: A Theoretical Study

Structure, optical absorption, and charge transport properties of dibenzocoronene tetracarboxdiimide (DCDI) based molecules were studied using electronic structure calculations. Based on the optimized neutral, cationic, and anionic geometries the ionized state properties, such as ionization potential, electron affinity, hole extraction potential, electron extraction potentials, and reorganization energy, were calculated. On the basis of the ground state geometry of the studied molecules, the absorption spectra were calculated using the time-dependent density functional theory (TDDFT) method at the PBE0/def-TZVP level of theory. It has been observed that the substitution of different functional groups significantly alters the absorption spectra of DCDI. The methoxy- (OCH₃-) substituted DCDI molecule has a maximum absorption wavelength of 529 nm. The charge transport parameters, such as the charge transfer integral, spatial overlap integral, and the site energy, are calculated directly from the Kohn-Sham matrix elements. The reorganization energy for the presence of excess positive and negative charges and the charge transfer rate calculated from Marcus' theory were used to find the mobility of charge carriers. The computed results show that the mobility of charge carriers is strongly influenced by the functional groups present on the DCDI molecule. The effect of intermolecular structural fluctuations on charge transport properties was studied through molecular dynamics and Monte Carlo simulations based on the polaron hopping mechanism. The calculated charge carrier mobility shows that the cyano- (CN-) substituted DCDI molecules are having n-type semiconducting property while, methoxy- (OCH₃-) and thiol- (SH-) substituted DCDI molecules exhibit ambipolar semiconducting properties.

A hyperacute immune map of ischaemic stroke patients reveals alterations to circulating innate and adaptive cells

Systemic immune changes following ischaemic stroke are associated with increased susceptibility to infection and poor patient outcome due to their role in exacerbating the ischaemic injury and long-term disability. Alterations to the abundance or function of almost all components of the immune system post-stroke have been identified, including lymphocytes, monocytes and granulocytes. However, subsequent infections have often confounded the identification of stroke-specific effects. Global understanding of very early changes to systemic immunity is critical to identify immune targets to improve clinical outcome. To this end, we performed a small, prospective, observational study in stroke patients with immunophenotyping at a hyperacute time point (< 3 h) to explore early changes to circulating immune cells. We report, for the first time, decreased frequencies of type 1 conventional dendritic cells (cDC1), haematopoietic stem and progenitor cells (HSPCs), unswitched memory B cells and terminally differentiated effector memory T cells re-expressing CD45RA (TEMRA). We also observed concomitant alterations to human leucocyte antigen D-related (HLA-DR), CD64 and CD14 expression in distinct myeloid subsets and a rapid activation of CD4+ T cells based on CD69 expression. The CD69+ CD4+ T cell phenotype inversely correlated with stroke severity and was associated with naive and central memory T (TCM) cells. Our findings highlight early changes in both the innate and adaptive immune compartments for further investigation as they could have implications the development of post-stroke infection and poorer patient outcomes.

Regulation of Thiamine (Vitamin B1)-Dependent Metabolism in Mammals by p53

Transcriptional factor p53 is a master regulator of energy metabolism. Energy metabolism strongly depends on thiamine (vitamin B1) and/or its natural derivatives. Thiamine diphosphate (ThDP), which is a major thiamine derivative, affects p53 binding to DNA. In order to elucidate the mechanism of regulation of thiamine-dependent metabolism by p53, we assessed putative p53-binding sites near transcription starting points in genes coding for transporters and enzymes, whose function is associated with thiamine and/or its derivatives. The predictions were validated by studying cell metabolic response to the p53 inducer cisplatin. Expression of p53 and its known target, p21, has been evaluated in cisplatin-treated and control human lung adenocarcinoma A549 cells that possess functional p53 pathway. We also investigated the activity of enzymes involved in the thiamine-dependent energy metabolism. Along with upregulating the expression of p53 and p21, cisplatin affected the activities of metabolic enzymes, whose genes were predicted as carrying the p53-binding sites. The activity of glutamate dehydrogenase GDH2 isoenzyme strongly decreased, while the activities of NADP+-dependent isocitrate dehydrogenase (IDH) and malic enzymes, as well as the activity of 2-oxoglutarate dehydrogenase complex at its endogenous ThDP level, were elevated. Simultaneously, the activities of NAD+-dependent IDH, mitochondrial aspartate aminotransferase, and two malate dehydrogenase isoenzymes, whose genes were not predicted to have the p53-binding sequences near the transcription starting points, were upregulated by cisplatin. The p53-dependent regulation of the assayed metabolic enzymes correlated with induction of p21 by p53 rather than induction of p53 itself.

The influence of the shape and configuration of sensitizer molecules on the efficiency of DSSCs: a theoretical insight

The sensitizer is an active component of dye sensitized solar cell (DSSC) technology, which is highly influential for the performance of DSSCs. The present study attempts to investigate the relationship between the shape of the sensitizer molecule and efficiency of DSSCs. Specifically, 17 different structures were investigated, and classified into four categories based on the shape of the dye molecule, namely L-shaped (linear), V-shaped, X-shaped and Y-shaped, and into two different categories based on the donor moiety. The five of studied structures contained a triphenylamine (TPA) donor moiety, and twelve structures contained carbazole (CAR) donor moiety. Parameters related to the performance of DSSCs such as absorption spectra, intramolecular charge transfer indices, frontier molecular orbitals, light harvesting efficiency, excited-state lifetime, exciton binding energy, electrostatic potential, charge transfer and electron injection ability were studied using results obtained from electronic structure calculations. The analysis of these various parameters showed that the linear-shaped and V-shaped sensitizers possess better photon absorption ability, and the V-shaped structure is best suited shape for applications in high performance DSSCs.

Numerous studies have reported that the shape of a sensitizer matters for DSSC performance, while the present study investigates why and how it matters.

Students Perception of their Educational Environment in a Medical College in India- A Survey using DREEM Questionnaire

Introduction: Educational plays an important role in the achievement of student’s academic success. Understanding the perception of students towards their educational environment helps to identify the lacunae in the curriculum and make the changes accordingly. Aim: To assess the perceptions of the students towards medical education using Dundee Ready Educational Environment Measure (DREEM) questionnaire as a tool. Materials and Methods: This was a cross-sectional study done at NRI Medical College, Guntur, Andhra Pradesh, India, from September 2020 to December 2020. A total of 414 students participated in the study. The DREEM questionnaire was used to collect the data. The questionnaire consists of five components with 50 statements assessed on five-point Likert scale (0-4). Data were expressed as mean and standard deviation, frequency, and percentages. Independent t-test and one-way Analysis of Variance (ANOVA) were used for comparing the groups. Results: Out of 600 students, 414 filled in the forms and submitted them (response rate was 69%). 266 (64.2%) were female and 148 (35.8%) were males. Age of the students ranged from 17 to 25 years with mean age 22.64±2.62 years. The mean DREEM score of study population was 130±6.7/200 which indicated a more positive than negative perception of learning. Subscale scores for student’s perception of learning, perceptions of teachers, academic self-perceptions, perceptions of atmosphere and social self-perceptions were 30.9±2.4, 28.9±1.5, 22.4±3.1, 30.8±2.3 and 16.9±1.7 respectively. Conclusion: There was a positive perception of students towards their educational environment. Strong areas were student’s confidence, teacher’s knowledge, and curricular relevance. Weak areas were identified as the inability to provide constructive criticism by teachers, the teachers were authoritarian and necessary steps can be taken for the improvement.

Airway closing index in school-age children during exercise bronchoprovocation

OBJECTIVE

Airway Closing Index (ACI), the ratio of % change in FVC to % change in FEV₁ with bronchoprovocation, may represent changes in airflow due to airway closure, as opposed to airway narrowing. The objective of this study was to evaluate ACI during exercise bronchoprovocation (EB) in children.

METHODS

Children, 6 to 18 years of age, who underwent EB using a stationary bicycle ergometer over a 6-year period were reviewed. Pulmonary function, including ACI, in patients with a positive exercise challenge, defined as ≥10% decrease in FEV₁ following exercise, were compared to patients with a negative challenge.

RESULTS

A total of 1030 children with a median age of 13 (IQR 11-15) underwent EB, of which 376 (37%) had a positive exercise challenge. There was wide variability in ACI, with a median of 0.75 (0.28-1.21). Median ACI in those with a positive test was 0.68 (IQR 0.41-0.93) compared to 0.84 (IQR 0.09-1.06) for those with a negative test, p = 0.017. Median ACI was higher in older children (p < 0.001) and females (p < 0.0001). Median percent change in FEV₁ following bronchodilator for children in the highest quintile for ACI was 4.5 (IQR 1.3-8.1) compared to 5.5 (IQR 2-9.2) for children in the lowest quintile, p = 0.04.

CONCLUSIONS

There is wide variability in the ACI in children undergoing EB. ACI was lower in children with a positive challenge, the significance is unknown. Children with higher ACI may have increased airway closure with bronchoprovocation, and less response to bronchodilators.

Transmitted Home Oximetry and Duration of Home Oxygen in Premature Infants

OBJECTIVES

To determine if a home oxygen therapy (HOT) management strategy that includes analysis of recorded home oximetry (RHO) data, compared with standard monthly clinic visit assessments, reduces duration of HOT without harm in premature infants.

METHODS

The RHO trial was an unmasked randomized clinical trial conducted in 9 US medical centers from November 2013 to December 2017, with follow-up to February 2019. Preterm infants with birth gestation ≤37 + 0/7 weeks, discharged on HOT, and attending their first pulmonary visit were enrolled. The intervention was an analysis of transmitted RHO between clinic visits (n = 97); the standard-care group received monthly clinic visits with in-clinic weaning attempts (n = 99). The primary outcomes were the duration of HOT and parent-reported quality of life. There were 2 prespecified secondary safety outcomes: change in weight and adverse events within 6 months of HOT discontinuation.

RESULTS

Among 196 randomly assigned infants (mean birth gestational age: 26.9 weeks; SD: 2.6 weeks; 37.8% female), 166 (84.7%) completed the trial. In the RHO group, the mean time to discontinue HOT was 78.1 days (SE: 6.4), compared with 100.1 days (SE: 8.0) in the standard-care group (P = .03). The quality-of-life scores improved from baseline to 3 months after discontinuation of HOT in both groups (P = .002), but the degree of improvement did not differ significantly between groups (P = .75).

CONCLUSIONS

RHO was effective in reducing the duration of HOT in premature infants. Parent quality of life improved after discontinuation. RHO allows physicians to determine which infants can be weaned and which need prolonged oxygen therapy between monthly visits.

Cross validated serum small extracellular vesicle microRNAs for the detection of oropharyngeal squamous cell carcinoma

BACKGROUND

Oropharyngeal squamous cell carcinoma (OPSCC) is often diagnosed at an advanced stage because the disease often causes minimal symptoms other than metastasis to neck lymph nodes. Better tools are required to assist with the early detection of OPSCC. MicroRNAs (miRNAs, miRs) are potential biomarkers for early head and neck squamous cell cancer diagnosis, prognosis, recurrence, and presence of metastatic disease. However, there is no widespread agreement on a panel of miRNAs with clinically meaningful utility for head and neck squamous cell cancers. This could be due to variations in the collection, storage, pre-processing, and isolation of RNA, but several reports have indicated that the selection and reproducibility of biomarkers has been widely affected by the methods used for data analysis. The primary analysis issues appear to be model overfitting and the incorrect application of statistical techniques. The purpose of this study was to develop a robust statistical approach to identify a miRNA signature that can distinguish controls and patients with inflammatory disease from patients with human papilloma virus positive (HPV +) OPSCC.

METHODS

Small extracellular vesicles were harvested from the serum of 20 control patients, 20 patients with gastroesophageal reflux disease (GORD), and 40 patients with locally advanced HPV + OPSCC. MicroRNAs were purified, and expression profiled on OpenArray™. A novel cross validation method, using lasso regression, was developed to stabilise selection of miRNAs for inclusion in a prediction model. The method, named StaVarSel (for Stable Variable Selection), was used to derive a diagnostic biomarker signature.

RESULTS

A standard cross validation approach was unable to produce a biomarker signature with good cross validated predictive capacity. In contrast, StaVarSel produced a regression model containing 11 miRNA ratios with potential clinical utility. Sample permutations indicated that the estimated cross validated prediction accuracy of the 11-miR-ratio model was not due to chance alone.

CONCLUSIONS

We developed a novel method, StaVarSel, that was able to identify a panel of miRNAs, present in small extracellular vesicles derived from blood serum, that robustly cross validated as a biomarker for the detection of HPV + OPSCC. This approach could be used to derive diagnostic biomarkers of other head and neck cancers.

Impact of Synthesis Technique on Lanthanum Doped Copper Oxide Nanocrystals, an Alternative Counter Electrode for Pt-Free Dye-Sensitized Solar Cells

The ascendancy of a counter electrode (C.E) in a dye-sensitized solar cell (DSSC) has an unrivaled impact on the performance of the dye-sensitized solar cell, where the Pt-based C.E has set up a phenomenal benchmark against its counterparts. Due to the high cost of such noble metals, an operative and a much cost effective replacement were greatly in demand to gratify this need. To address this issue, monoclinic lanthanum doped copper oxide (CuO) nanoparticles were prepared by solution combustion and co-precipitation techniques respectively as they possess highly superior optoelectronic, catalytic and charge transfer properties. The effect of incorporating lanthanum (La) ions and the variation of synthesis technique on their structural, optical, photo-thermal and morphological properties are empirically investigated by XRD, FTIR, TEM, UV-Vis, Raman and Photoacoustic Spectroscopy (PAS). The X-ray diffraction pattern revealed the formation of La-doped CuO nanoparticles. The finger-print vibrational modes of the as-synthesized samples are confirmed by the FTIR spectra. The required optical properties of the as-synthesized nanocrystals were confirmed using UV-Vis absorption spectra, from which the bandgap was determined by Kubelka-Munk plot. The Raman modes were determined using Raman spectra, further a multi-phonon band was revealed, which was formed due to the plasmon-phonon coupling. The photothermal phenomenon was revealed using the photoacoustic spectra. The morphological investigation by TEM found the change in the morphology of the material as the synthesis route is varied. The power conversion efficiency results unveiled that the combustion-derived C.E posted a promising efficiency (η) of 0.20% and the co-precipitation derived C.E posted an efficiency of 0.02%. Overall results suggest that the combustion derived La doped CuO nanostructures exhibited substantive properties with deeper implication and also stood out to be a viable, cost-effective and self-exemplifying replacement for Pt as C.E in DSSC's.

A systematic review and meta-analysis of cancer patients affected by a novel coronavirus

BACKGROUND

Cancer patients with COVID-19 disease have been reported to have double the case fatality rate of the general population.

MATERIALS AND METHODS

A systematic search of PubMed/MEDLINE, Embase, Cochrane Central, Google Scholar, and MedRxiv was done for studies on cancer patients with COVID-19. Pooled proportions were calculated for categorical variables. Odds ratio and forest plots were constructed for both primary and secondary outcomes. The random-effects model was used to account for heterogeneity between studies.

RESULTS

This systematic review of 31 studies and meta-analysis of 181,323 patients from 26 studies involving 23,736 cancer patients is the largest meta-analysis to the best of our knowledge assessing outcomes in cancer patients affected by COVID-19. Our meta-analysis shows that cancer patients with COVID-19 have a higher likelihood of death (odds ratio, OR 2.54), which was largely driven by mortality among patients in China. Cancer patients were more likely to be intubated, although ICU admission rates were not statistically significant. Among cancer subtypes, the mortality was highest in hematological malignancies (OR 2.43) followed by lung cancer (OR 1.8). There was no association between receipt of a particular type of oncologic therapy and mortality. Our study showed that cancer patients affected by COVID-19 are a decade older than the normal population and have a higher proportion of co-morbidities. There was insufficient data to assess the association of COVID-directed therapy and survival outcomes in cancer patients. Despite the heterogeneity of studies and inconsistencies in reported variables and outcomes, these data could guide clinical practice and oncologic care during this unprecedented global health pandemic.

CONCLUSION

Cancer patients with COVID-19 disease are at increased risk of mortality and morbidity. A more nuanced understanding of the interaction between cancer-directed therapies and COVID-19-directed therapies is needed. This will require uniform prospective recording of data, possibly in multi-institutional registry databases.

Investigation on Elastic, Magnetic, Optical and Electrical Impedance Properties of Dysprosium Doped Nickel Ferrite Nanocrystals

Rare earth dysprosium (Dy) doped nickel ferrite nanoparticles were synthesized via economically viable co-precipitation technique and studied for its elastic, structural, magnetic and electrical properties. X-ray diffraction analysis shows the formation of cubic spinel phase with a slight inclination in the cell parameters with respect to the concentration of dopant convivial. The crystallite size and strain of the nanoparticles were determined using Scherrer formula and the Williamson-Hall (W-H) technique. In addition, the theoretical parameters viz., cation distribution, bond length, oxygen positional parameters, etc., have been embrasured. The strength and types of interionic bonds in the nano ferrites were determined utilizing Fourier Transform Infrared spectral analysis. The magnetic properties were analysed using vibrating sample magnetometer at room temperature, it was found that as the dopant concentration increases, the coercivity and magnetic saturation decreases. This result is partially explained by the bridge networking of Dy³⁺-Fe³⁺ ions which is equated by Fe²⁺- Fe³⁺ ion interaction. This paper deals with the itinerant electron model to determine the distribution of cations by magnetization analysis. The optical properties of the samples were studied utilizing UV-Vis spectral analysis and the optical band gap was evaluated from Kubelka-Munk plot. Electrical impedance was analysed as a function of frequencies at room temperature. This analysis depicts the dielectric constant and loss factor tends to decline with applied frequency and AC conductivity elicits its semiconducting characteristic by obeying Jonscher's law.

Malignant Transformation of Hypertrophic Lichen Planus in a Young Pregnant Woman: A Case Report

In this article, we report a case of hypertrophic lichen planus transforming into cutaneous squamous cell carcinoma in a 24-year-old Indian woman at 34 weeks of gestational age. We hypothesize that immunologic alterations during pregnancy could transform a long-standing hypertrophic lichen planus into cutaneous neoplasm.

OS12.4 In vivo dynamics and targeting of vessel co-option in glioma

BACKGROUND

Gliomas comprise heterogeneous malignant glial and stromal cells. While blood vessel co-option is a potential mechanism to escape anti-angiogenic therapy, the relevance of glial phenotype in this process is unclear.

MATERIAL AND METHODS

Here, we intravitally study preclinical syngenetic models of glioma as well as patient-derived cells transplanted orthotopically. Moreover, we profoundly confirm our preclinical results with histological studies on patient specimens.

RESULTS

We show that Olig2+ oligodendrocyte precursor-like glioma cells invade by single-cell vessel co-option and preserve the blood-brain barrier (BBB). Conversely, Olig2-negative glioma cells form dense perivascular collections and promote angiogenesis and BBB breakdown, leading to innate immune cell activation. Experimentally, Olig2 promotes Wnt7b expression, a finding that correlates in human glioma profiling. Targeted Wnt7a/7b deletion or pharmacologic Wnt inhibition blocks Olig2+ glioma single-cell vessel co-option and enhances responses to temozolomide. Finally, Olig2 and Wnt7 become upregulated after anti-VEGF treatment in preclinical models and patients.

CONCLUSION

Here, we show that glioma is able to employ vessel co-option, i.e. the movement of tumor cells towards and along the pre-existing vasculature.

Glioma oligodendrocyte-like (OPCL) cells express Wnt7 that is necessary for vessel co-option and Wnt inhibitors significantly improve survival with temozolomide. Moreover, we demonstrated that anti-VEGF-treatment of glioma selects for Olig2/Wnt7+ cells