Influence of Polyfluorinated Side Chains and Soft-Template Method on the Surface Morphologies and Hydrophobic Properties of Electrodeposited Films from Fluorene Bridged Dicarbazole Monomers

A clear case of relationship between the monomer molecular structure and the capability of tuning the morphology of electrodeposited gas bubbles template polymer thin films is shown. To this end, a series of fluorene-bridged dicarbazole derivatives containing either linear or terminally branched polyfluorinated side chains connected to the fluorene subunit were synthesized and their electrochemical properties were investigated. The new compounds underwent electrochemical polymerization over indium tin oxide electrodes to give hydrophobic films with nanostructural and morphological properties strongly dependent on the nature of the side chains. Gas bubbles templated electropolymerization was next achieved by the addition of tiny amounts of water to the monomer solutions, without using surfactants. Within the investigated set of molecules, the nanostructural properties of the soft-templated films obtained from monomers bearing linear side chains could be fine-tuned by adjusting electrochemical parameters, leading to superhydrophobic surfaces.

Untangling the influence of depression on clinical risks: role of leukocytes and somatic symptoms

Background

Depression has been associated with increased hospitalization and mortality risk, especially for cardiovascular causes. We previously found a composite circulating inflammation score (INFLA-score) to explain part of this link, although the role of its component and of depressive symptoms domains in this relationship is unexplored.

Methods

In an Italian population cohort (N = 13,191; age≥35 years; 51.7 % women; 4,856 hospitalizations and 471 deaths, median follow-up 7.28/8.24 years), we estimated the proportion of association explained by C-reactive protein levels (CRP), platelet count, granulocyte-to-lymphocyte ratio (GLR) and white blood cell counts (WBC), in multivariable Cox regressions modelling first hospitalization/mortality for all and cardiovascular (CVD), ischemic heart (IHD) and cerebrovascular disease (CeVD) causes vs depression severity based on an alternative validated version of PHQ-9. We also estimated the proportion of association explained by INFLA-score in the associations of polychoric factors tagging somatic and cognitive depressive symptoms with clinical risks.

Results

In models adjusted for age, sex and education, significant proportions of the positive influence of depression on clinical risks were explained by CRP (4.8% on IHD hospitalizations), GLR (11% on all-cause mortality) and WBC (24% on IHD/CeVD hospitalizations). Stable associations of somatic but not of cognitive depressive symptoms were observed with increased hospitalization risk (+16% for all causes, +14% for CVD causes), with INFLA-score again explaining small but significant proportions of these associations (2.5% for all causes, 8.6% for IHD causes).

Conclusions

These findings suggest a prominent explanatory role of leukocytes in the link between depression and clinical (especially CVD) risks, and highlight the importance of inflammation in the influence of somatic depressive symptoms. Therefore, acting on these factors may reduce clinical risks associated with depression.

Key messages

Design and synthesis of new luminescent coordination networks of topology showing the highest degrees of interpenetration

The highest degree of interpenetration reported so far of 7- and 8-fold is realized in two luminescent sql 2D networks by self-assembly of a new nanometric-sized ligand with Ag(i) salts.

Spatial Charge Separation as the Origin of Anomalous Stark Effect in Fluorous 2D Hybrid Perovskites

2D hybrid perovskites (2DP) are versatile materials, whose electronic and optical properties can be tuned through the nature of the organic cations (even when those are seemingly electronically inert). Here, it is demonstrated that fluorination of the organic ligands yields glassy 2DP materials featuring long-lived correlated electron-hole pairs. Such states have a marked charge-transfer character, as revealed by the persistent Stark effect in the form of a second derivative in electroabsorption. Modeling shows that electrostatic effects associated with fluorination, combined with the steric hindrance due to the bulky side groups, drive the formation of spatially dislocated charge pairs with reduced recombination rates. This work enriches and broadens the current knowledge of the photophysics of 2DP, which will hopefully guide synthesis efforts toward novel materials with improved functionalities.

Vacuum-Induced Degradation of 2D Perovskites

Two-dimensional (2D) hybrid organic-inorganic perovskites have recently attracted the attention of the scientific community due to their exciting optical and electronic properties as well as enhanced stability upon exposure to environmental factors. In this work, we investigate 2D perovskite layers with a range of organic cations and report on the Achilles heel of these materials—their significant degradation upon exposure to vacuum. We demonstrate that vacuum exposure induces the formation of a metallic lead species, accompanied by a loss of the organic cation from the perovskite. We investigate the dynamics of this reaction, as well as the influence of other factors, such as X-ray irradiation. Furthermore, we characterize the effect of degradation on the microstructure of the 2D layers. Our study highlights that despite earlier reports, 2D perovskites may exhibit instabilities, the chemistry of which should be identified and investigated in order to develop suitable mitigation strategies.

Fluorination of Organic Spacer Impacts on the Structural and Optical Response of 2D Perovskites

Low-dimensional hybrid perovskites have triggered significant research interest due to their intrinsically tunable optoelectronic properties and technologically relevant material stability. In particular, the role of the organic spacer on the inherent structural and optical features in two-dimensional (2D) perovskites is paramount for material optimization. To obtain a deeper understanding of the relationship between spacers and the corresponding 2D perovskite film properties, we explore the influence of the partial substitution of hydrogen atoms by fluorine in an alkylammonium organic cation, resulting in (Lc)₂PbI₄ and (Lf)₂PbI₄ 2D perovskites, respectively. Consequently, optical analysis reveals a clear 0.2 eV blue-shift in the excitonic position at room temperature. This result can be mainly attributed to a band gap opening, with negligible effects on the exciton binding energy. According to Density Functional Theory (DFT) calculations, the band gap increases due to a larger distortion of the structure that decreases the atomic overlap of the wavefunctions and correspondingly bandwidth of the valence and conduction bands. In addition, fluorination impacts the structural rigidity of the 2D perovskite, resulting in a stable structure at room temperature and the absence of phase transitions at a low temperature, in contrast to the widely reported polymorphism in some non-fluorinated materials that exhibit such a phase transition. This indicates that a small perturbation in the material structure can strongly influence the overall structural stability and related phase transition of 2D perovskites, making them more robust to any phase change. This work provides key information on how the fluorine content in organic spacer influence the structural distortion of 2D perovskites and their optical properties which possess remarkable importance for future optoelectronic applications, for instance in the field of light-emitting devices or sensors.

Improving the Electropolymerization Properties of Fluorene-Bridged Dicarbazole Monomers through Polyfluoroalkyl Side Chains

The facile functionalization of the fluorene scaffold at the 2,7-positions was utilized to provide access to two soluble carbazole-π-carbazole derivatives CFC-H1 and CFC-F1 featuring fully hydrogenated and polyfluorinated alkyl chains at the 9-position of the fluorene π-bridging unit, respectively. The optical and electrochemical properties of the new dicarbazoles were investigated. Their electrochemical polymerization over Pt and indium tin oxide electrodes allowed the generation of electroactive polymeric films, whose physicochemical characteristics were strongly dependent on the kind of alkyl chain present on the fluorene bridge. In particular, the electropolymerization of the polyfluorinated monomer allowed the fabrication of thin films with good electrical conductivity, reversible electrochemical processes, good electrochromic properties, and enhanced water repellency with respect to its nonfluorinated analogue.

BODIPY Dyes Bearing Multibranched Fluorinated Chains: Synthesis, Structural, and Spectroscopic Studies

A small series of boron-dipyrromethene (BODIPY) dyes, characterized by the presence of multibranched fluorinated residues, were designed and synthesized. The dyes differ in both the position (para-perfluoroalkoxy-substituted phenyl ring or boron functionalization) and number of magnetically equivalent fluorine atoms (27 or 54 fluorine atoms per molecule). Photophysical and crystallographic characterization of the synthesized BODIPYs was carried out to evaluate the effect of the presence of highly fluorinated moieties on the optical and morphological properties of such compounds.

Water-Repellent Low-Dimensional Fluorous Perovskite as Interfacial Coating for 20% Efficient Solar Cells

Hybrid perovskite solar cells have been capturing an enormous research interest in the energy sector due to their extraordinary performances and ease of fabrication. However, low device lifetime, mainly due to material and device degradation upon water exposure, challenges their near-future commercialization. Here, we synthesized a new fluorous organic cation used as organic spacer to form a low-dimensional perovskite (LDP) with an enhanced water-resistant character. The LDP is integrated with three-dimensional (3D) perovskite absorbers in the form of MA_0.9FA_0.1PbI₃ (FA = NH₂CH = NH₂⁺, MA = CH₃NH₃⁺) and Cs_0.1FA_0.74MA_0.13PbI_2.48Br_0.39. In both cases, a LDP layer self-assembles as a thin capping layer on the top of the 3D bulk, making the perovskite surface hydrophobic. Our easy and robust approach, validated for different perovskite compositions, limits the interface deterioration in perovskite solar cells yielding to >20% power conversion efficient solar cells with improved stability, especially pronounced in the first hours of functioning under environmental conditions. As a consequence, single and multijunction perovskite devices, such as tandem solar cells, can benefit from the use of the waterproof stabilization here demonstrated, a concept which can be further expanded in the perovskite optoelectronic industry beyond photovoltaics.

Dye-sensitized solar cells based on a push-pull zinc phthalocyanine bearing diphenylamine donor groups: computational predictions face experimental reality

Computational studies have suggested that the integration of secondary amine as donor groups in the structure of unsymmetrical zinc phthalocyanine (ZnPc) should have positive effects on photovoltaic performance, once the molecule is integrated as light harvester in dye sensitized solar cells (DSSCs). Aiming at obtaining experimental confirmation, we synthesized a peripherally substituted push-pull ZnPc bearing three electron donating diphenylamine substituents and a carboxylic acid anchoring group and integrated it as sensitizer in TiO₂-based DSSCs. Detailed functional characterization of solar energy converting devices resulted in ruling out the original hypothesis. The causes of this discrepancy have been highlighted, leading to a better understanding of the conditions for an effective design of push-pull diarylamino substituted ZnPcs for DSSCs.

Femtosecond Charge-Injection Dynamics at Hybrid Perovskite Interfaces

With a power conversion efficiency (PCE) exceeding 22 %, perovskite solar cells (PSCs) have thrilled photovoltaic research. However, the interface behavior is still not understood and is a hot topic of research: different processes occur over a hierarchy of timescales, from femtoseconds to seconds, which makes perovskite interface physics intriguing. Herein, through femtosecond transient absorption spectroscopy with spectral coverage extending into the crucial IR region, the ultrafast interface-specific processes at standard and newly molecularly engineered perovskite interfaces in state-of-the-art PSCs are interrogated. Ultrafast interfacial charge injection occurs with a time constant of 100 fs, resulting in hot transfer from energetic charges and setting the timescale for the first step involved in the complex charge-transfer process. This is also true for 20 % efficient devices measured under real operation, for which the femtosecond injection is followed by a slower picosecond component. These findings provide compelling evidence for the femtosecond interfacial charge-injection step and demonstrate a robust method for the straightforward identification of interfacial non-equilibrium processes on the ultrafast timescale.

Phonetic analysis during treatment with rapid maxillary expander

OBJECTIVES

To investigate possible changes and/or device-related impairments in phonetic habits produced by rapid maxillary expansion (RME).

MATERIALS AND METHODS

Thirty-five patients scheduled for RME were divided into two groups: Group A (banded two-arm Hyrax) and Group B (banded four-arm Hyrax). Speech samples were collected at six time points, before, during and after RME removal. Acoustical analysis was performed using PRAAT and BioVoice analysis tools. Ten volunteers completed a questionnaire on the acceptability of patient's speech. Maxillary dimensions and palatal volume were measured on dental casts before and after expansion using a digital gauge.

RESULTS

Voice analysis showed an increase in the peak frequency of fricative consonants (/s/,/ʃ/) after expansion, whereas there was no change of formant frequencies of palatal consonants (/ɲ/,/ʎ/). Vowel /i/ displayed a lowering of the first formant frequency, and an increase in the second and third formant frequencies. After bonding, Group B showed both a greater reduction in the peak frequency of fricatives and a greater increase in the formant frequencies of palatal consonants than Group A.

CONCLUSION

Rapid maxillary expansion causes a slight phonetic change in the acoustical parameters of both consonants and vowels. The two-arm Hyrax caused less speech impairment than the four-arm Hyrax during the treatment.

Fluorous molecules for dye-sensitized solar cells: synthesis and properties of di-branched, di-anchoring organic sensitizers containing fluorene subunits

Four organic sensitizers having a di-branched molecular structure D–(π–A)₂ were applied in the development of dye-sensitized solar cells (DSSCs).

Automatic newborn cry analysis: a non-invasive tool to help autism early diagnosis

Autism Spectrum Disorders (ASD) are complex developmental disabilities that cause problems with social interaction and communication. ASD are associated with motor development problems, more or less blurred, and with perceptual and sensory brain areas. Crying is the infant's earliest form of communication and recent studies connect this original "language" form with autism disturbs. Being completely non-invasive, cry analysis is an appealing approach for early ASD diagnosis to improve rehabilitation. To this aim, we have developed an automatic system to record newborn cry and movements, during the first six months of life with a specific recording protocol. In this work we present first results of acoustic cry analysis in newborns classified as high-risk subjects being siblings of children already diagnosed as autistics. The work aims at finding possible early ASD signs in high-risk subjects as compared to a group of control subjects based on the fundamental frequency and the vocal tract resonance frequencies. Also, voiced and unvoiced parts of signal and cry-episodes duration are analyzed.

High-resolution cry analysis in preterm newborn infants

Infant monitoring is a common procedure in clinical practice in neonatal critical care units. A number of vital functions are monitored, such as heart beat, breathing, blood flow, etc. Specifically, preterm and/or low-birth-weight infants often present respiratory problems that require monitoring. These may range from insufficient ventilation to apnoea. One of the most common events that may affect the respiratory flow is crying, a physiological action made by the infant to communicate and draw attention, but, for a preterm infant, this action requires great effort, which may cause distress and even may have an adverse impact on blood oxygenation. Acoustic analysis of newborn infant cry is thus of importance, since it is related to other basic neuro-physiological parameters. Being easy to perform, cheap and completely non-invasive, it can be successfully applied in many circumstances. The newborn infant cry is characterised by very high fundamental frequency (F(0)) and resonance frequency (RFs) values, with abrupt changes and voiced/unvoiced features of very short duration in a single utterance. To deal with such signals, a new user-friendly software tool has been developed, that allows robust tracking of main acoustic parameters on very short and time-varying signal frames. The software developed provides the user with a high-resolution picture of the cry signal characteristics.

Non-invasive distress evaluation in preterm newborn infants

With the increased survival of very preterm infants, there is a growing concern for their developmental outcomes. Infant cry characteristics reflect the development and possibly the integrity of the central nervous system. In this paper, relationships between fundamental frequency (F(0)) and vocal tract resonance frequencies (F(1)-F(3)) are investigated for a set of preterm newborns, by means of a multi-purpose voice analysis tool (BioVoice), characterised by high-resolution and tracking capabilities. Also, first results about possible distress occurring during cry in preterm newborn infants, as related to the decrease of central blood oxygenation, are presented. To this aim, a recording system (Newborn Recorder) has been developed, that allows synchronised, non-invasive monitoring of blood oxygenation and audio recordings of newborn infant's cry. The method has been applied to preterm newborns at the Intensive Care Unit, A.Meyer Children Hospital, Firenze, Italy.

Enhanced activity of a hydrogen sulphide-releasing derivative of mesalamine (ATB-429) in a mouse model of colitis

BACKGROUND AND PURPOSE

Mesalamine is the first-line therapy for colitis, but it lacks potency and is only effective for mild-to-moderate forms of this disease. Hydrogen sulphide has been shown to be a potent, endogenous anti-inflammatory substance, modulating leukocyte-endothelial adhesion and leukocyte migration. The purpose of this study was to determine if an H(2)S-releasing derivative of mesalamine (ATB-429) would exhibit increased potency and effectiveness in a mouse model of colitis.

EXPERIMENTAL APPROACH

Colitis was induced in mice with trinitrobenzene sulphonic acid and the effects of ATB-429 and mesalamine were compared in several treatment regimens. The severity of colitis was determined using several indices, including a disease activity score (comprised of scores for diarrhea, weight loss and fecal blood), colonic myeloperoxidase activity and macroscopic/microscopic scoring of tissue injury.

KEY RESULTS

Irrespective of the treatment regiment, ATB-429 was more effective than mesalamine in reducing the severity of colitis. ATB-429 was particularly effective in reducing granulocyte infiltration into the colonic tissue (by approximately 70%), as well as reducing the expression of mRNA for several key proinflammatory cytokines/chemokines (e.g., TNFalpha, IFNgamma). Treatment with ADT-OH, the H(2)S-releasing moiety of ATB-429, did not affect severity of colitis.

CONCLUSIONS AND IMPLICATIONS

ATB-429 exhibits a marked increase in anti-inflammatory activity and potency in a murine model of colitis, as compared to mesalamine. These results are consistent with recently described anti-inflammatory effects of H(2)S. ATB-429 may represent an attractive alternative to mesalamine for the treatment of inflammatory bowel disease.

Very Mild, Enantioselective Synthesis of Propargylamines Catalyzed by Copper(I)−Bisimine Complexes

The stereoselective addition of aryl- and alkylacetylene derivatives to imines was studied. The reaction is catalyzed by copper complexes of enantiomerically pure bisimines, readily prepared in very high yields from the commercially available binaphthyl diamine. A very simple experimental procedure allowed to obtain at room temperature optically active propargylamines in high yields and enantioselectivity. Interestingly, bisimine/copper(I) complexes were able to promote the direct, enantioselective, catalytic addition to imines of alkylacetylenes. The effects of catalyst loading and other reaction parameters on the stereochemical outcome of the transformation were investigated. The extremely convenient methodology, the mild reaction conditions, and the possibility of a modular approach for developing new and more efficient bisimine-based chiral ligands make the present methodology very attractive.

A reusable, insoluble polymer-bound bis(oxazoline) (IPB-box) for highly enantioselective heterogeneous cyclopropanation reactionsElectronic supplementary information (ESI) available: experimental. See http://www.rsc.org/suppdata/cc/b3/b306483b/

A reusable, insoluble polystyrene-supported bis(oxazoline) was developed, affording e.e.s > 90% in the heterogeneous enantioselective cyclopropanation of styrene and 1,1-disubstituted alkenes with ethyl diazoacetate.

Vasodilator stress echocardiography for risk stratification of medically stabilized unstable angina

AIMS

The aims of this study were to assess the safety, feasibility and prognostic value of dipyridamole-atropine stress echo in patients with medically stabilized unstable angina.

METHODS

The initial population consisted of 173 patients consecutively admitted at two different Coronary Care Units with class IIIB unstable angina. Of these, 56 were excluded: five had poor acoustic window, 24 did not stabilize with medical therapy and underwent urgent coronary angiography, 26 evolved in non-Q wave myocardial infarction and one patient died. The remaining 117 patients underwent dipyridamole-atropine stress echo after 48 h without symptoms or electrocardiographic evidence of myocardial ischaemia.

RESULTS

No complications or side effects occurred. An ischaemic response was found in 61 patients. During follow-up (10+/-9 months), three cardiac deaths, eight infarctions, 13 unstable anginas, and seven late (>3 months from stress testing) revascularizations occurred. There were 22 events (36%) in patients with, and nine events (16%) in patients without, inducible ischaemia (P=0.01). At Cox analysis peak-stress wall-motion score index (HR=5.5; 95% CI, 1.9 to 15.5; P=0.0015), and admission ST-segment depression (HR=4.2; 95% CI, 1.7 to 10.7; P=0.0022) were independent predictors of spontaneous events (cardiac death, infarction, unstable angina). The 12-month event-free survival was 69% for ischaemic and 83% for non-ischaemic group (P=0.03). In considering major events as end-points (spontaneous events, and late revascularization), again multivariate prognostic indicators were peak-stress wall-motion score index (HR=14.2; 95% CI, 2.6 to 76.6; P=0.0021), and admission ST-segment depression (HR=3.1; 95% CI, 1.4 to 6.9; P=0.0055). The 12-month event-free survival rate was 58% for ischaemic and 81% for non-ischaemic group (P=0.002). With an interactive stepwise procedure, stress echo findings were found to provide incremental prognostic contribution to that of clinical data alone.

CONCLUSIONS

With proper selection of patients, dipyridamole-atropine stress echo is extremely safe and feasible in patients with medically stabilized unstable angina, and can be useful in identification of subjects at risk for future cardiac events.