Synthesis of star-shaped poly(lactide)s, poly(valerolactone)s and poly(caprolactone)s ROP catalyzed by N-donor tin(ii) cations and comparison of their wetting properties with linear analogues.

In this study, we report the use of N-coordinated tin(ii) cations [L→Sn(HO)][OTf]·THF (1) and [L→SnCl][SnCl] (2) (L = 1,2-(CHN-2-CH = N)CHCH) as efficient ROP catalysts, which, in combination with benzyl alcohol, afford well-defined linear poly(ε-caprolactone) (PCL) and poly(δ-valerolactones) (PVL) an activated monomer mechanism (AMM). Thanks to the versatility of complexes 1 and 2 as catalysts, star-shaped PCL, PVL and PLA were also prepared using three-, four-, five- and six-functional alcohols. The number of arms was determined by SEC-MALS-Visco analysis.

Ultra-high-frequency ECG volumetric and negative derivative epicardial ventricular electrical activation pattern.

From precordial ECG leads, the conventional determination of the negative derivative of the QRS complex (ND-ECG) assesses epicardial activation. Recently we showed that ultra-high-frequency electrocardiography (UHF-ECG) determines the activation of a larger volume of the ventricular wall. We aimed to combine these two methods to investigate the potential of volumetric and epicardial ventricular activation assessment and thereby determine the transmural activation sequence.

Nrf2 depletion in the context of loss-of-function Keap1 leads to mitolysosome accumulation.

Transcription factor nuclear factor erythroid 2 p45-related factor 2 (Nrf2) is the principal determinant of the cellular redox homeostasis, contributing to mitochondrial function, integrity and bioenergetics. The main negative regulator of Nrf2 is Kelch-like ECH associated protein 1 (Keap1), a substrate adaptor for Cul3/Rbx1 ubiquitin ligase, which continuously targets Nrf2 for ubiquitination and proteasomal degradation. Loss-of-function mutations in Keap1 occur frequently in lung cancer, leading to constitutive Nrf2 activation.

Tin(II) cations stabilized by non-symmetric N,N',O-chelating ligands: synthesis and stability.

A series of novel non-symmetric neutral N,N',O-chelating ligands derived from the α-iminopyridine 2-(C(R)N(CH-2,6-iPr))-6-(RRPO)CHN (L1: R = H, R = R = Ph; L2: R = Me, R = R = Ph; L3: R = H; R = Ph, R = EtO; L4: R = Me, R = Ph, R = EtO; L5: R = H, R = R = iPrO; L6: R1 = Me, R = R = iPrO) were synthesized. Ligands L1-6 were reacted with SnCl and Sn(OTf) with the aim of studying the influence of different RRPO functional groups on the Lewis base mediated ionization of SnCl and Sn(OTf). While all ligands L1-6 provided the corresponding ionic tin(II) complexes [L1-6 → SnCl][SnCl] (1-6), only ligands L1, L4 and L6 were able to stabilize tin(II) dications [L1,4,6 → Sn(HO)][OTf] (7-9).

Comparison of mononuclear and dinuclear copper(II) biomimetic complexes: spectroelectrochemical mechanistic study of their catalytic pathways.

Two catecholase-like biomimetic catalysts, namely, two dinuclear copper complexes [Cu(L1)(OH)(HO)(EtOH)][ClO] (C1) and [CuAcO(L1)ClO] (C2) with the 2,6-bis(4-methyl piperazin-1-yl-methyl)-4-formyl-phenoxy ligand (L1) together with the mononuclear complex Cu(ClO)(L2) (C3) containing ligand 1,2-(CHN-6-OCH-2-CHN)CHCH (L2), were synthesized. Their catalytic pathways were investigated and compared. The evaluation of the catalytic activity of compound C1 (and C2, C3) using the Michaelis-Menten model was represented by values of = 272.

Correction: Sýs et al. Bis(2,2'-bipyridil)Copper(II) Chloride Complex: Tyrosinase Biomimetic Catalyst or Redox Mediator? 2021, , 113.

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Reduced Radiation Exposure Protocol during Computer Tomography of the Left Atrium Prior to Catheter Ablation in Patients with Atrial Fibrillation.

(1) Background: Computer tomography (CT) is an imaging modality used in the pre-planning of radiofrequency catheter ablation (RFA) procedure in patients with cardiac arrhythmias. However, it is associated with a considerable ionizing radiation dose for patients. This study aims to develop and validate low-dose CT scanning protocols of the left atrium (LA) for RFA guidance.

N-Donor stabilized tin(II) cations as efficient ROP catalysts for the synthesis of linear and star-shaped PLAs the activated monomer mechanism.

α-Iminopyridine ligands L (2-(CHN(CH-2,4,6-Ph))CHN), L (2-(CHN(CH-2,4,6-Bu))CHN) and L (1,2-(CHN-2-CHN)CHCH) differing by the steric demand of the substituent on the imine CHN group and by the number of donating nitrogen atoms were utilized to initiate a Lewis base mediated ionization of SnCl in an effort to prepare ionic tin(II) species [L → SnCl][SnCl]. The reaction of L and L with SnCl led to the formation of neutral adducts [L → SnCl] (2) and [L → SnCl] (3). The preparation of the desired ionic compounds was achieved by subsequent reactions of 2 and 3 with an equivalent of SnCl or GaCl.

CDKL5 kinase controls transcription-coupled responses to DNA damage.

Mutations in the gene encoding the CDKL5 kinase are among the most common genetic causes of childhood epilepsy and can also give rise to the severe neurodevelopmental condition CDD (CDKL5 deficiency disorder). Despite its importance for human health, the phosphorylation targets and cellular roles of CDKL5 are poorly understood, especially in the cell nucleus. Here, we report that CDKL5 is recruited to sites of DNA damage in actively transcribed regions of the nucleus.

Single-Chamber Cardiac Pacemaker Implantation in a Donkey with Complete AV Block: A Long-Term Follow-Up.

A five-month-old African jenny was presented with a history of exercise intolerance and syncopal episodes. Severe bradycardic arrhythmia due to a high-grade second-degree atrioventricular (AV) block with progression to complete AV block was diagnosed. The jenny underwent a transvenous single-chamber pacemaker implantation.

Bis(2,2'-bipyridil)Copper(II) Chloride Complex: Tyrosinase Biomimetic Catalyst or Redox Mediator?

In this article, construction of amperometric sensor(s) based on screen-printed carbon electrodes covered by thin layers of two types of carbon nanomaterials serving as amplifiers, and containing [Cu(bipy)Cl]Cl∙5HO complex is reported. Their performance and biomimetic activity towards two selected neurotransmitters (dopamine and serotonin) was studied mainly using flow injection analysis (FIA). The important parameters of FIA such as working potential, flow rate, and pH were optimized.

Preparation and Characterisation of Waste Poultry Feathers Composite Fibreboards.

The growth of poultry meat production is increasing industrial waste quantities every year. Feathers represent a huge part of the waste, and international directives and restrictions prevent landfilling of such biodegradable materials with high burning values. Furthermore, with their unique properties, poultry waste feathers are already a reliable resource for many byproducts, such as keratin extraction, fibres, hydrogel production, etc.

Novel ultra-high-frequency electrocardiogram tool for the description of the ventricular depolarization pattern before and during cardiac resynchronization.

Introduction: The present study introduces a new ultra-high-frequency 14-lead electrocardiogram technique (UHF-ECG) for mapping ventricular depolarization patterns and calculation of novel dyssynchrony parameters that may improve the selection of patients and application of cardiac resynchronization therapy (CRT).

Methods: Components of the ECG in sixteen frequency bands within the 150 to 1000 Hz range were used to create ventricular depolarization maps. The maximum time difference between the UHF QRS complex centers of mass of leads V1 to V8 was defined as ventricular electrical dyssynchrony (e-DYS), and the duration at 50% of peak voltage amplitude in each lead was defined as the duration of local depolarization (Vd).

Feasibility of directional percutaneous epicardial ablation with a partially insulated catheter.

Purpose: To demonstrate the feasibility of directional percutaneous epicardial ablation using a partially insulated catheter.

Methods: Partially insulated catheter prototypes were tested in 12 (6 canine, 6 porcine) animal studies in two centers. Prototypes had interspersed windows to enable visualization of epicardial structures with ultrasound.

Electrochemical and Reactivity Studies of N→Sn Coordinated Distannynes.

Studies are focused on the redox potentials of N→Sn coordinated distannnynes {L Sn} (L =1, L =2 and L =3, in which L is [C H -2,6-(Me NCH ) ] , L is [C H -2,4-tBu -6-(Et NCH )] and L is [C H -2,4-tBu -6-(DippN=CH)] ; Dipp=2,6-diisopropylphenyl), containing the tin atom in oxidation state +I. Distannynes 1-3 were used as ligands for transition metals, and complexes [{L Sn} ⋅Fe(CO) ] (4) and [{L Sn} ⋅Fe(CO) ] (5) were prepared. The set of N→Sn coordinated distannynes 1-5 was studied by cyclic voltammetry measurements and the oxidation potentials of tin atoms in 1-5 were determined.

A Novel Defibrillation Tool: Percutaneously Delivered, Partially Insulated Epicardial Defibrillation.

Introduction: Epicardial defibrillation systems currently require surgical access. We aimed to develop a percutaneous defibrillation system with partially-insulated epicardial coils to focus electrical energy on the myocardium and prevent or minimize extra-cardiac stimulation.

Methods: We tested 2 prototypes created for percutaneous introduction into the pericardial space via a steerable sheath.

Ventricular dyssynchrony assessment using ultra-high frequency ECG technique.

Purpose: The aim of this proof-of-concept study is to introduce new high-dynamic ECG technique with potential to detect temporal-spatial distribution of ventricular electrical depolarization and to assess the level of ventricular dyssynchrony.

Methods: 5-kHz 12-lead ECG data was collected. The amplitude envelopes of the QRS were computed in an ultra-high frequency band of 500-1000 Hz and were averaged (UHFQRS).

Prevalence and Predictors of Early Heart Failure With Preserved Ejection Fraction in Patients With Paroxysmal Atrial Fibrillation.

Background: Patients with atrial fibrillation (AF) have an increased risk of diastolic dysfunction and heart failure. The purpose of this study was to identify independent predictors of early (ie, only exercise-induced) heart failure with preserved ejection fraction (HFpEF) and to describe the prevalence of early HFpEF among patients with paroxysmal AF.

Methods And Results: One hundred patients with paroxysmal AF and preserved left ventricular ejection fraction (LVEF) underwent catheterization for left atrial pressure (LAP) measurements at rest and at the peak of arm exercise (LAP-exe).

Hydrosilylation of RN=CH Imino-Substituted Pyridines without a Catalyst.

Treatment of the neutral pyridine-based ligands L -L , bearing either one or two RN=CH imine moieties {where L and L are N,N-chelating ligands 2-(RN=CH)C H N (R=Ph (L ) or R=2,4,6-Ph C H (L )) and L is the N,N,N-chelating ligand 2,6-(RN=CH) C H N (R=2,6-iPr C H )}, with HSiCl yielded N→Si-coordinated silicon(IV) amides 2-{Cl SiN(R)CH }C H N (1, R=Ph; 2, R=2,4,6-Ph C H ) and 2-{Cl SiN(R)CH }-6-(RN=CH)C H N (3, R=2,6-iPr C H ). The organosilicon amides 1-3 are the products of spontaneous hydrosilylation of the RN=CH imine moiety induced by N→Si coordination of the proposed N,N-chelated chlorosilanes L →SiHCl (1 a), L →SiHCl (2 a), and L →SiHCl (3 a). Furthermore, the reaction of L with an excess of HSiCl provided the intramolecularly coordinated chlorosilicon diamide cyclo-{(C H N)-1,3-(CH NR) }SiCl (4) (R=2,6-iPr C H ) as the product of spontaneous reduction of both RN=CH imine moieties.

Three-dimensional rotational angiography of the left atrium and the oesophagus: the short-term mobility of the oesophagus and the stability of the fused three-dimensional model of the left atrium and the oesophagus during catheter ablation for atrial fibrillation.

Aims: The objective of this study was to evaluate the mobility of the oesophagus and the stability of the three-dimensional (3D) model of the oesophagus using 3D rotational angiography (3DRA) of the left atrium (LA) and the oesophagus, fused with live fluoroscopy during catheter ablation for atrial fibrillation.

Methods And Results: From March 2015 to September 2015, 3DRA of the LA and the oesophagus was performed in 33 patients before catheter ablation for atrial fibrillation. Control contrast oesophagography was performed every 30 min.

Improvement in the prediction of exercise-induced elevation of left ventricular filling pressure in patients with normal left ventricular ejection fraction.

Background: Noninvasive diagnosis of exercise-induced elevation of left ventricular filling pressure is difficult and remains unsatisfactory. The aim of this study was to assess the accuracy of the ratio of early diastolic transmitral (E) to mitral annular (e') velocity and to determine new parameters or parameter combinations with the ability to predict exercise-induced left atrial pressure (LAP) elevation.

Methods And Results: Eighty patients with paroxysmal atrial fibrillation (AF) referred for catheter AF ablation underwent simultaneous exercise echocardiography and direct invasive LAP measurements, as well as a resting and postexercise biomarker analysis.

Percutaneous Epicardial Pacing using a Novel Insulated Multi-electrode Lead.

Introduction: Epicardial cardiac resynchronization therapy (CRT) permits unrestricted electrode positioning. However, this requires surgical placement of device leads and the risk of unwanted phrenic nerve stimulation. We hypothesized that shielded electrodes can capture myocardium without extracardiac stimulation.

Periprocedural 3D imaging of the left atrium and esophagus: comparison of different protocols of 3D rotational angiography of the left atrium and esophagus in group of 547 consecutive patients undergoing catheter ablation of the complex atrial arrhythmias.

A new method in creating 3D models of the left atrium (LA) and esophagus before catheter ablation of atrial arrhythmias is 3D rotational angiography (3DRA) of the LA. The purpose of this retrospective study was to test various acquisition protocols of the 3DRA and attempt to define the parameters influencing the success of the protocols. From August 2010 to November 2014, 3DRA of the LA using the Philips Allura FD 10 X-ray system was performed in 547 consecutive patients using right atrial and left atrial protocols.