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We demonstrate a functionalization strategy to improve the basic fluorescence properties and to systematically customize the bandgap properties of Graphene quantum dots (GQD) by functionalization with a well-known fluorophore called Dithienopyrrole derivative (DTPAN) whereby making them adequately acceptable for the suitable promising applications. We observed that the functionalization with DTPAN not only shifts the photoluminescence spectrum but also enhances the other inherent fluorescence properties. The functionalized material (DTPAN-fn-GQD) is used for the sensitive detection of Pb2+ ions in aqueous media. The detection of Pb2+ within the linear range of 0.5–40 nM was obtained with a limit of detection of 0.25 nM. Stern–Volmer analysis suggests that both static and dynamic mechanisms are active for the quenching process and further the Cyclic Voltammetry measurements along with DFT calculations of DTPAN-fn-GQD recommend the possibility of electron transfer from the HOMO of DTPAN to the LUMO of GQD upon photoexcitation. However, the presence of Pb2+ metal ions will perturbate this charge transfer process and lead to quenching of fluorescence. The sensor was applied efficiently to the determination of Pb2+ ions in real water samples. Paper strips based on the developed fluorescent probe were shown to be useful for rapid visual sensing, which can expand its potential ability for developing simple analytical devices.

Recently graphene quantum dot (GQD) based nanohybrid materials have received much attention. Herein, a highly fluorescent biocompatible GQD and N-functionalized dithienopyrrole (DTP-PPD) modified nanohybrid system was fabricated (DTP-PPD-fn-GQD) for the first time. Modification resulted in stable fluorescence with a quantum yield of approximately 22% and 36 nm redshift compared to unmodified GQD. The apparent bandgap tuning along with fluorescence property changes was investigated by cyclic voltammetry measurements and density functional theory studies. This water-soluble system was then applied for the sensitive and selective detection of Pb2+ ions. As a result of a specific interaction towards Pb2+ ions, the fluorescence intensity was quenched. The detection limit is found to be 1.02 nM within the linear range of 3 to 30 nM. Finally, the feasibility of the developed probe was tested with real samples of water. Chemically modified GQDs are already widely exploited for Pb2+ sensing, whereas GQD/thiophene-based nanohybrid systems are less utilized. This newly developed nanohybrid of GQD (DTP-PPD-fn-GQD) has excellent fluorescence properties and bandgap tunability. Moreover, effective fluorometric sensing of Pb2+ ions in an aqueous medium is well investigated. This gives more insight into developing GQD-based highly promising nanohybrid colorimetric as well as fluorescent sensors.

A heterocyclic Schiff base (MPDPI)was synthesized by the condensation reaction of 1-phenylisatin with 4,5-dimethylphenylene diamine. It was characterized by using spectroscopic methods including UV visible, Infrared, 1H-NMR, 13C-NMR and mass spectrometry. It acts as the fluorescent probe for the detection of Vitamin B12 (Vit.B12) which shows high selectivity over other species via dynamic quenching mechanism. It is also highly sensitive towards Vit.B12 with a detection limit of $$1.18 \times {10}^{-9}$$ M and showed a linear concentration ranging from $$1\times {10}^{-7 }M$$ to $$5\times {10}^{-7 }M$$ . Effect of other coexisting species was also studied. The satisfactory results were also obtained in real samples.Since, there are only few reports on Vit.B12, development of selective fluorescent probes for Vit.B12 would be worthwhile.

A novel Schiff base ligand, 3-(2-amino-4,5-dimethyl-phenylimino)-5-phenyl-1,3-dihydro-indol-2-one (MPD 5MI), was developed and characterized using spectroscopic methods, including UV-visible, infrared, 1H-NMR, 13C-NMR, and mass spectrometry. The essential fluorescence properties, such as the quantum yield, Stokes shift, and average lifetime value, of the newly synthesized Schiff base-derived fluorophore were investigated. Inspired by the excellent fluorescence properties achieved, a turn-off fluorescence sensor was conceived for the detection of cysteine, in which the fluorescence intensity of the probe was quenched upon the addition of cysteine via a combined static and dynamic quenching mechanism. It also gives a low detection limit of 3.97 × 10−11 Mand a linear range of 2 × 10−7 M to 5 × 10−7 M under the optimized conditions. It also demonstrates the selective detection of cysteine even with the existence of biologically relevant amino acids. To gain more information about the structure–property relationship of the system, HOMO–LUMO energy levels were calculated using experimental and theoretical studies (DFT calculations), which correlated with good agreement. Furthermore, the practical sensing abilities of the probe were investigated in real samples, showing satisfactory results.

Recently graphene quantum dot (GQD) based nanohybrid materials have received much attention. Herein, a highly fluorescent biocompatible GQD and N-functionalized dithienopyrrole (DTP-PPD) modified nanohybrid system was fabricated (DTP-PPD-fn-GQD) for the first time. Modification resulted in stable fluorescence with a quantum yield of approximately 22% and 36 nm redshift compared to unmodified GQD. The apparent bandgap tuning along with fluorescence property changes was investigated by cyclic voltammetry measurements and density functional theory studies. This water-soluble system was then applied for the sensitive and selective detection of Pb

Charge-transfer processes from photoexcited CdSe quantum dots (QDs) to phenol derivatives with electron- donating (4-methoxy) and -withdrawing (4-nitro) moieties have been demonstrated by using steady-state and time- resolved emission and femtosecond transient absorption spectroscopy. Steady-state and time-resolved emission studies suggest that in the presence of both 4-nitrophenol (4NP) and 4-methoxyphenol (4MP) CdSe QDs luminescence is quenched. Stern-Volmer analysis suggests both static and dynamic mechanisms are active for both the QD/phenol composites. Cyclic voltammetric analysis recommends that photoexcited CdSe QDs can donate electrons to 4NP and holes to 4MP. To reconfirm both electron- and hole-transfer mechanisms, CdSe/CdS quasi-type II and CdSe/CdTe type II core-shell nanocrystals were synthesized and photoluminescence quenching was monitored in the absence and presence of both 4NP and 4MP, for which hole and electron transfer were systematically restricted. Results suggest that indeed electron and hole transfer take place from photoexcited CdSe to 4NP and 4MP, respectively. To monitor the charge-transfer dynamics in both systems on an early timescale, femtosecond transient absorption spectroscopic techniques have been employed. Electron and hole transfer and charge-recombination dynamics are discussed and the effect of electron-donating and -withdrawing groups has been demonstrated.

BACKGROUND: Remote ischaemic conditioning with transient ischaemia and reperfusion applied to the arm has been shown to reduce myocardial infarct size in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). We investigated whether remote ischaemic conditioning could reduce the incidence of cardiac death and hospitalisation for heart failure at 12 months. METHODS: We did an international investigator-initiated, prospective, single-blind, randomised controlled trial (CONDI-2/ERIC-PPCI) at 33 centres across the UK, Denmark, Spain, and Serbia. Patients (age >18 years) with suspected STEMI and who were eligible for PPCI were randomly allocated (1:1, stratified by centre with a permuted block method) to receive standard treatment (including a sham simulated remote ischaemic conditioning intervention at UK sites only) or remote ischaemic conditioning treatment (intermittent ischaemia and reperfusion applied to the arm through four cycles of 5-min inflation and 5-min deflation of an automated cuff device) before PPCI. Investigators responsible for data collection and outcome assessment were masked to treatment allocation. The primary combined endpoint was cardiac death or hospitalisation for heart failure at 12 months in the intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT02342522) and is completed. FINDINGS: Between Nov 6, 2013, and March 31, 2018, 5401 patients were randomly allocated to either the control group (n=2701) or the remote ischaemic conditioning group (n=2700). After exclusion of patients upon hospital arrival or loss to follow-up, 2569 patients in the control group and 2546 in the intervention group were included in the intention-to-treat analysis. At 12 months post-PPCI, the Kaplan-Meier-estimated frequencies of cardiac death or hospitalisation for heart failure (the primary endpoint) were 220 (8·6%) patients in the control group and 239 (9·4%) in the remote ischaemic conditioning group (hazard ratio 1·10 [95% CI 0·91-1·32], p=0·32 for intervention versus control). No important unexpected adverse events or side effects of remote ischaemic conditioning were observed. INTERPRETATION: Remote ischaemic conditioning does not improve clinical outcomes (cardiac death or hospitalisation for heart failure) at 12 months in patients with STEMI undergoing PPCI. FUNDING: British Heart Foundation, University College London Hospitals/University College London Biomedical Research Centre, Danish Innovation Foundation, Novo Nordisk Foundation, TrygFonden. The ERIC-PPCI trial was funded by a British Heart Foundation clinical study grant (grant number CS/14/3/31002) and a University College London Hospitals/University College London Biomedical Research Centre clinical research grant. The CONDI-2 trial was funded by Danish Innovation Foundation grants (grant numbers 11-108354 and 11-115818), Novo Nordisk Foundation (grant number NNF13OC0007447), and TrygFonden (grant number 109624). DJH was supported by the British Heart Foundation (grant number FS/10/039/28270), the National Institute for Health Research (NIHR) Biomedical Research Centre at University College London Hospitals, the Duke-National University Singapore Medical School, the Singapore Ministry of Health’s National Medical Research Council under its Clinician Scientist-Senior Investigator scheme (grant number NMRC/CSA-SI/0011/2017) and its Collaborative Centre Grant scheme (grant number NMRC/CGAug16C006), and the Singapore Ministry of Education Academic Research Fund Tier 2 (grant number MOE2016-T2-2-021). HEB was supported by the Novo Nordisk Foundation (grant numbers NNF14OC0013337, NNF15OC0016674). RKK is supported by the Oxford NIHR Biomedical Centre. The research was also supported by the NIHR infrastructure at Leeds. The views expressed are those of the author(s) and not necessarily those of the National Health Service, the NIHR, or the Department of Health. This article is based on the work of COST Action EU-CARDIOPROTECTION (CA16225) and supported by COST (European Cooperation in Science and Technology). We thank all study personnel for their invaluable assistance. Sí

Owing to the importance of pyranopyrazole scaffolds, several methods for their synthesis were developed. The previous reports on the synthesis of pyranopyrazole derivatives suffered many drawbacks which included difficulty in the workup, longer reaction time, high cost of catalyst and use of organic solvents. The present article reports the use of low melting mixture as a catalyst and solvent for the synthesis of pyranopyrazole derivatives. A study on the physical properties of the new Lactic Acid: Urea: NH4Cl low melting mixture such as density, viscosity, acidity, refractive index, surface tension is reported. IR spectra, 1H NMR spectra, emission spectra, polarity and cytotoxicity were also studied. The application in the synthesis of pyranopyrazole derivatives was established. The present method of synthesis of pyranopyrazole derivatives followed a simple procedure and easy workup protocol. The reaction was performed without the use of organic solvents. The components used in the mixture were easily available. The reaction required only less time and reactions were done at 28 ​°C.