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Polyolefins, composed of carbon and hydrogen atoms, dominate global polymer production. This stems from the wide range of physical and mechanical properties that various polyolefins can cover. Their versatile properties are largely tuned by chain microstructure, including molar mass distribution, comonomer content, and long‐chain branching (LCB). Specifically, LCB imparts unique characteristics, notably enhances processability crucial for downstream applications. Tailoring LCB structural features has encouraged academic and industrial efforts, chronicle in this review from a chemistry standpoint. While encompassing post‐reaction modification based traditional methods like peroxide grafting, ionizing beam irradiation, and coupling reactions, the main focus is given to catalyst‐centric strategies and innovative polymerization schemes. The advent of single‐site catalysts—metallocenes and late transition metals catalysts—amplifies interest in tailored chemical methods, but the progress in LCB formation flourishes via tandem catalytic systems and bimetallic catalysts under controlled reaction conditions. Specifically, the breakthrough in coordinative chain transfer polymerization unveils a novel avenue for controlled LCB synthesis by sequential chain propagation, transfer, liberation, and enchainment. This short review highlights recent approaches for the production of LCB polyolefins that can provide a roadmap crucial for researchers in academia and industry, steering their efforts toward further advancements in the production of tailored polyolefin. [ABSTRACT FROM AUTHOR]

Background: Enzyme combinations, particularly phytase (PHY) with various carbohydrases and proteases, are utilized in commercial broiler production to enhance nutrient and energy bioavailability. Objective: A feeding study was undertaken to determine whether the efficiency of an Escherichia coli–derived PHY and a feed enzyme complex (FEC) derived from Bacillus spp. containing carbohydrase and protease as main activities in broiler chickens is dependent on diet quality. A total of 900 male one‐day‐old broiler chickens (Ross 308) were assigned to a 2 × 3 factorial arrangement of the treatments with 2 different nutrient density diets, standard nutrient diet (SN diet) and a low‐nutrient diet (LN diet; −100 kcal/kg for AMEn and −5% for crude protein [CP] and limiting amino acids), and 3 enzyme treatments (control [no enzymes], PHY and PHY + FEC). Each treatment group was composed of 6 replicates of 25 birds each. Results: The LN diet caused a decrease in performance index, tibia length and diameter, tibia calcium content and jejunal villus surface area (VSA). The interaction effects between diet and enzyme supplementation were observed (p < 0.05) on overall average daily gain (ADG), performance index, tibia ash content and jejunal villus height (VH) and VSA, with the favourable benefits of PHY + FEC treatment being more pronounced in the LN diets. Regardless of dietary nutrient density, supplementation with PHY alone or combined with FEC enhanced (p < 0.05) final body weight, overall ADG and jejunal villus height (VH)/crypt depth, with the highest values observed in the PHY + FEC group. The PHY + FEC treatment also improved (p < 0.05) overall feed conversion ratio, apparent ileal digestibility of dry matter, organic matter, CP, and energy, and tibia phosphorus content compared to the control treatment. Conclusions: The results indicate that the simultaneous addition of PHY and FEC to the LN diets improved the growth rate, bone mineralization and gut morphology. [ABSTRACT FROM AUTHOR]

The concept of mizaj corresponds to the idea of personalized medicine and is the main diagnostic principle of Persian medicine (PM). This study aims to investigate diagnostic tools for the detection of mizaj in PM. In this systematic review of articles published before September 2022, articles were searched for in the Web of Science, PubMed, Scopus, Google Scholar, SID databases, and gray literature. The titles of the articles were screened by researchers and relevant articles were selected. Abstracts were reviewed by two reviewers to select final articles. Subsequently, the articles found were critically evaluated by two reviewers according to the CEBM method. Finally, article data were extracted. Of the 1812 articles found, 54 were included in the final evaluation. Of these, 47 articles were related to the diagnosis of whole body mizaj (WBM). WBM was diagnosed in 37 studies using questionnaires and 10 using expert panels. In addition, six articles examined the mizaj of organs. Only four of these questionnaires were found with reported reliability and validity. There were two questionnaires for assessing WBM, but neither had sufficient reliability and validity. Questionnaires that assess organs had weak designs and lacked sufficient reliability and validity. [ABSTRACT FROM AUTHOR]

Transient structures based on associative polymers can deliver complex functions; as such, they hold promise for advanced applications as in drug delivery, tissue engineering, and electronics. The network structure and timescale of its rearrangement are key factors that define their range of utility. However, the inevitable phase separation of polar pairwise associations from nonpolar polymer chains frequently causes junction aggregation, whose stability and functionality significantly affect the network structure and dynamics, and as such, redefine its utility. Engineering the extent of association is a necessity for controlling properties of supramolecular materials, yet the current knowledge of the effect of design parameters on specificities of aggregates and their consequent effects on material properties is limited. To address this gap, the importance of aggregation is highlighted, the available theories and models of the dynamics of associative polymers in the presence of aggregates are reviewed, and the existing experimental records to draw a general guideline for interpreting the effect of aggregates on polymer dynamics are classified. Moreover, pitfalls and considerations like the applicability of time–temperature superposition, and the interplay of kinetics and thermodynamics of aggregation that may undermine the authenticity of the reported data are reviewed. [ABSTRACT FROM AUTHOR]

A mechanical bond serves as a distinctive approach for harnessing the most beneficial features of both covalent and supramolecular chemistries, offering stability and structural adaptability owing to its unique dynamic nature. Molecules formed by mechanical bonding, known as mechanically interlocked molecules (MIMs) including catenanes, rotaxanes, and knots have opened new possibilities. Notably, the introduction of mechanically interlocked structures into polymers has led to the emergence of novel polymeric materials referred to as mechanically interlocked polymers (MIPs), such as polyrotaxanes and polycatenanes. The interlocked nature of these architectures can lead to particular conformational freedom and high mobility of their components, resulting in exceptional properties, such as ultra-stretchability, toughness, and immediate recoverability. These properties have found potential applications in diverse fields, including the development of tough hydrogels, scratch-resistant coatings, smart actuators, and batteries. Recent years have witnessed a surge in the synthesis and investigation of a diverse array of rotaxane-based MIPs, an essential class that has enabled researchers to begin grasping the impact of incorporating mechanical bonds within polymer structures, and of their mobility, on material properties. In this review, an overview of the dynamics of ring-containing polymers is presented. The review encompasses macromolecular rotaxanes, polyrotaxanes, and slide-ring networks, including the role of ring mobility in shaping the dynamics and properties of rotaxane polymers. [Display omitted] [ABSTRACT FROM AUTHOR]

The dynamic mechanical properties of supramolecular associative polymer networks depend on the average number of entanglements along the network‐forming chains, Ne, and on their content of associative groups, f. In addition, there may be further influence by aggregation of the associative groups into clusters, which, in turn, is influenced by the chemical structure of these groups, and again by Ne and f of the polymer. Therefore, the effects of these parameters are interdependent. To conceptually understand this interdependency, we study model networks in which (a) Ne, (b) f, and (c) the chemical structure of the associative groups are varied systematically. Each network is probed by rheology. The clustering of the associative groups is assessed by analyzing the rheological data at the end range of frequency covered and by comparison of the number of supramolecular network junctions with the maximum possible number of binary transient bonds. We find that if the total number of the network junctions, which can be formed either by interchain entanglement or by interchain transient associations, is greater than a threshold of 13, then the likelihood of cluster formation is high and the dynamics of supramolecular associative polymer networks is mainly controlled by this phenomenon. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1209–1223 [ABSTRACT FROM AUTHOR]

One of the current challenges of the Comprehensive Nuclear-Test-Ban Treaty Organization, is reducing the minimum detectable activity and increasing the precision of the detection of radioactive noble gases; namely 135Xe, 133Xe, 133mXe, and 131mXe. These gases are typically detected by systems that use beta-gamma coincidence spectroscopy and gamma spectroscopy for activity measurement. In all of them, a lead shield (passive guard) is used to reduce the environmental isotopes. In this work, the concept of the active guard used in LSC systems has been improved upon for gaseous radioactive samples in a phoswich detector through Geant4 simulations. The simulation results showed that the use of an active guard results in a reduction in the minimum detectable activity, compared to those without an active guard. [ABSTRACT FROM AUTHOR]

BACKGROUND: Despite recent advances in diagnostic techniques in cardiology, electrocardiography (ECG) has yet remained the first and corner stone of detecting emergency cardiac events including myocardial infarction (MI). There are some ECG findings which are considered as equivalents to MI. De Winter ST-T wave pattern is one of the important ECG findings which is thought to be related to left anterior descending artery occlusion. However, the coexistence of this ECG pattern with other ECG abnormalities are not reported widely. In this report, we discussed a unique case of de Winter ST-T wave pattern in a patient with Wolff- Parkinson-White (WPW) syndrome for the first time. CASE REPORT: A 43-year-old man was referred because of an intermittent typical chest pain. The patient had no cardiovascular risk factor, and was not on any medication; laboratory tests showed elevated and raising troponin I. The first ECG showed pre-excitation (WPW) as well as de winter pattern. According to patient's symptoms and suggestive ECG for probable left anterior descending (LAD) occlusion, emergent angiography was scheduled. The coronary angiography revealed sever LAD artery occlusion. The patient was symptom free after successful percutaneous coronary intervention, and was discharged on medication. The patient remained asymptomatic in 1-year follow-up period. CONCLUSION: Presence of de Winter ST-T changes with other ECG abnormalities is a rare issue, and here we addressed the first case of WPW and de Winter. The physicians should be aware that ECG changes in patients with WPW should not be interpreted as de Winter ST-T changes and vice versa. [ABSTRACT FROM AUTHOR]

[Display omitted] • Coordinative chain transfer copolymerization of ethylene and propylene is reported. • Significant change of composition is observed upon introducing the chain transfer agent. • Ethylene sequence length increases by the establishment of regenerative chain transfer. • DFT calculation is used to explain and compare different probable reaction pathways. • DFT results suggest the competition between the propylene insertion and chain transfer. The wide applications of ethylene–propylene copolymers, which range from elastomers to oligomeric lubricants and additives can be expanded upon controlling the microstructure specifically its chemical composition. To account for that we use rac -Et(Ind) 2 ZrCl 2 metallocene catalyst in combination with modified methylaluminoxane (MMAO) as the cocatalyst and ZnEt 2 as the chain transfer agent (CTA) in a coordinative chain transfer copolymerization. The monotonic decline of molar mass and narrowing of its distribution in the presence of CTA suggest the establishment of the regenerative chain transfer reaction. The end-group analysis by 1H NMR spectroscopy demonstrates the depletion of β-H transfer and replacement of chain transfer to CTA. Microstructure analysis of copolymers by 13C NMR reveals a significant increase in ethylene content, which raises smoothly by CTA content, along with modification of the microstructure at the triad level, suggesting the prevalence of ethylenic sequences. This is in line with the decrease of the glass transition temperature and appearance of a broad melting peak between 30 and 90 °C. We explain these experimental observations by a computational study at the DFT level that compares three reaction pathways of ethylene and propylene insertion into an ethylene-ended propagating chain or chain transfer to the CTA. The outcome shows that propylene insertion is kinetically less feasible compared to ethylene insertion or chain transfer, while thermodynamically the chain transfer reaction is less favored. These results establish a new kinetics control over the chain microstructure in ethylene–propylene copolymers. [ABSTRACT FROM AUTHOR]

Background: Dobutamine stress echocardiography (DSE) is a non-invasive technique to detect coronary artery diseases (CAD). There are limited studies on evaluation of the right ventricular function by stress echocardiography. The appropriate evaluation of RV function and early diagnosis of its failure can help to improve outcomes for the patients undergoing cardiac surgery. Objective: To determine right ventricular dysfunction in patients with three-vessel CAD by using DSE. Methods: This cross-sectional study was among 13 patients who were candidates for coronary artery bypass grafting (CABG) referred to Ghaem Hospital, Mashhad, Iran; from September 2015 to May 2016. After a physical examination and initial measures, DSE was performed and echocardiographic parameters were recorded by a cardiologist. Paired-samples t-test was performed using SPSS Software v.16.0 for data analysis. Results: The study included 13 patients (9 males) with a mean age of 65.4±7.6 years. The mean of TAPS was 16.9±4.5 mm and 15.7±2.9 mm before and after stress echocardiography, respectively (p=0.69). Systolic right ventricular (SRV) peak increased from before DSE compared with after DSE (8.0±2.2 vs. 13.7±4.2 mm/s, p<0.001). In addition, after dobutamine injection, right ventricular (RV) cardiac output decreased in 7 patients and one patient was affected by post-ejection shortening. Conclusion: It seems that TAPS and RV cardiac output after injection of dobutamine, can be used as markers for the recognition of ischemic RV dysfunction. [ABSTRACT FROM AUTHOR]

Development of olefin block copolymers (OBCs) based on new catalytic systems is challenging. We evaluate the performance of rac-ethylenebis(1-η5-indenyl)zirconium dichloride (Zr) and bis(imino)pyridine iron (Fe) catalysts, with different comonomer affinities, in copolymerization of ethylene/1-hexene. In-depth investigation of thermal properties reveals that chain shuttling agent (CSA) has diverse effects on the microstructure formed by the individual catalysts. Specifically, as confirmed by CNMR measurements, the comonomer affinity of the Zr catalyst is noticeably reduced while it remains unchanged for the Fe catalyst. Copolymers produced by the binary catalytic system in the presence of CSA do not show indications for formation of blocky structure at higher Zr fractions, while at lower fractions, a significantly different behavior is exposed, e.g., high melting temperature peak is replaced by broad low-temperature endotherm and lower molar mass with narrow distribution is obtained. It could be concluded that this catalyst composition can be a good candidate for operative production of OBCs. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the efficacy and safety of superior peripheral iridotomy versus inferior peripheral iridotomy in the treatment of primary angle-closure glaucoma (PACG) in phakic patients.Methods: In this randomized, prospective, paired-eye comparative study, patients with primary angle closure or primary angle-closure suspects were recruited and randomized to receive neodymium-doped yttrium aluminum garnet (Nd:YAG) laser peripheral iridotomy (LPI) superiorly in one eye and inferiorly in the other eye. Patients were masked to the location of treatment in each eye. The main outcome measures were patency of iridotomy, intraocular pressure (IOP), complications and visual symptoms at each postoperative visit during a 1 year follow-up.Results: A total of 164 patients were recruited, of whom 150 (91.46%) completed the study. The mean age was 58.85 ± 6.4 years. Average IOP measurements before LPI was 22.85 ± 7.53 and 23.62 ± 8.32 in superior LPI and inferior LPI eyes respectively. After LPI, average IOP was 25.14 ± 2.73 and 20.97 ± 2.72 in superior LPI and inferior LPI eyes respectively. Inferior LPIs required less use of mean total laser energy to perforate the tissue (p = .05) and resulted in a significantly lower incidence of iris bleeding at the time of treatment (p = .004), lower IOP elevation following treatment (p = .002), lower incidence of focal corneal damage (p = .002) and a lower post-laser iritis (p = .04). All the 300 iridotomies were patent at 12 month follow up.Conclusion: The inferior LPI appeared to be an efficient method of preventing pupil block with fewer complications. Visual symptoms following inferior LPI are similar to superior LPI. [ABSTRACT FROM AUTHOR]

Unbridged oscillatory metallocenes are prone to produce heterogeneous chain microstructure, for instance, giving rise to elastomeric polypropylene. Here, we use the bis(2-phenylindenyl)ZrCl 2 /MAO catalyst system, featuring oscillating ligands, to copolymerize ethylene with several α-olefins. Through investigation of chain microstructure, thermal and rheological properties, we show that the complex behavior of these materials can be justified by considering a catalyst with dual active center having different comonomer affinities. This behavior is consistent with the proposed mechanism of fast oscillating ligands, becoming locked upon proximity of cocatalyst counteranion, leading to diverse stereo- and comonomer selectivity. The unlocked, oscillating active center with lower comonomer response gives rise to mostly linear chains and is not affected by the presence of comonomer, while the locked one creates long chain branched chains, whose frequency decreases by introduction of comonomer. Copolymer samples exhibited bimodal MWD, dual crystallization mechanisms, and low frequency plateau modulus, specifically at higher comonomer levels. It was concluded that the overall behavior is determined by complex interplay of SCB and LCB, which leads to thermorheological complexity as well as phase separation. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new tandem dual catalytic system for the formation of long branches is introduced. • Regenerative chain transfer polymerization is combined with chain displacement reaction. • Macromers are released upon displacement of dormant chains with ethylene. • Macromer reincorporation results in formation of long chain branches (LCBs) • LCB formation has a profound effect on microstructure and rheology of polymers. • The displacement reaction pathways are analyzed by DFT simulation. The controlled introduction of long chain branches (LCBs) in the commonly linear structure of polyolefins has been frequently pursued by researchers to improve their melt processability. To account for that, we introduce a new tandem dual catalytic system for the formation of LCB in ethylene polymerization. Coordinative chain transfer polymerization in the first step produces Al-alkyls via frequent transfer of growing polymer chains from the single-site α-diimine nickel polymerization catalyst to AlEt 2 Cl chain transfer agent (CTA). Next, the displacement catalyst, Ni(acac) 2 , converts the dormant alkyl chains into macromers through a β-hydride elimination and retrieves the Al-based CTA. Due to the high comonomer affinity of the polymerization catalyst, the released macromers are incorporated in growing polymer chains. By repeating this reaction cycles, a branch-on-branch structure is formed. Interestingly, a separate cocatalyst is not required, as AlEt 2 Cl serves as both the cocatalyst and the CTA for the CCTP system. This reaction scheme employs the "nickel-effect" mechanism for the formation of LCB in coordinative polymerization for the first time. The efficiency of the proposed mechanism in the formation of LCBs is confirmed by comprehensive rheological studies and NMR spectroscopy. Moreover, density functional theory (DFT) simulations rationalize the formation of LCBs through the proposed Ni-based displacement reaction. [ABSTRACT FROM AUTHOR]

BACKGROUND: Trans-radial coronary intervention is a popular technique due to patient comfort and lower complication rate. The main complications of this method are artery spasm, vessel perforation, and formation of pseudo-aneurysm. CASE REPORT: In this report, an unusual complication of radial access angiography was encountered. Shortly after the procedure, the patient's right arm began to swell and a pulsating mass grew over the medial aspect of the arm. Right brachial artery angiography was performed immediately for rolling out brachial artery perforation. There was no evidence of extravasation in brachial angiography. Surprisingly, the mass began to disappear after some active flexion and extension at elbow joint. The same problem occurred again after percutaneous coronary intervention (PCI) on left anterior descending artery (LAD) in this case 2 days later and was resolved by the same maneuver. CONCLUSION: It can be conculded that the brachial artery path was shifted and became entrapped after the procedure due to low soft tissue support. [ABSTRACT FROM AUTHOR]

Background: Reducing patients’ pain is one of the main goals of providing clinical services, which requires nursing skill. As a simple technique, increasing the duration of subcutaneous heparin injection may affect the intensity of pain and bruising. Objective: The aim of this study was to assess the effect of increasing the heparin injection time on pain intensity and bruising associated with subcutaneous injection. Methods: The present quasi-experimental study consisted of 86 patients, admitted to our hospital, who were treated with subcutaneous heparin injection. A McGill pain intensity questionnaire was used to measure pain severity in a purposive sampling. All of the subjects received subcutaneous heparin twice for 10 seconds. They also were injected twice with heparin infusion, although it was for 30 seconds this time. The interval between the two injections was 24 h, and the intensity of the pain was measured after each injection. The Pearson correlation coefficient was measured, and analysis of variance (ANOVA) and the t-test were used to analyze the data. Results: Eighty patients received heparin. The body mass indexes were reported as 52 (60%) and 34 (40%) for subjects within the age range of 18.5-24.9 and 25-29.9, respectively. Regarding the mean of pain intensity, there was a significant difference between the 10 and 30 s injections (p ˂ 0.05). Additionally, there was a significant difference in bruising rates between the two methods 48 and 72 h after injection (p ˂ 0.05). The ANOVA test showed a significant association between gender and bruising (p = 0.001). Conclusion: According to the results, by elevating the duration of heparin injection, the severity of pain was reduced, and, therefore, the patients felt more comfortable. Trial Registration: The trial was registered at the Thai Clinical Trials Registry (TCTR) with the TCTR identification of TCTR20160221001. Funding: This research was supported by the research cluster grant (88186-25/01/89) from Mashhad University of Medical Sciences, Mashhad, Iran. The authors received no financial support for the authorship and/or publication of this article. [ABSTRACT FROM AUTHOR]

• Coordination geometry is highlighted as an effective design parameter in MSPNs. • Ligands employed in MSPNs are differentiated based on their protic and aprotic nature. • Inconsistent deductions of the roles of coordination geometry are highlighted. • Self-sorting mechanisms of the supramolecular coordination complexes are reviewed. • Relevance of self-sorting mechanisms in designing novel MSPNs is laid out. Nature employs a wide library of transient interaction to operate adaptively on various time and length scales. Inspired by such elegant designs, combinations of different supramolecular assemblies have been extensively introduced in synthetic material platforms to obtain biomimetic functions. Among the most widely used transient bond, metal–ligand coordination performs a distinct role in designing robust and stimuli-responsive metallo-supramolecular polymer networks (MSPNs). The functionality of the metal–ligand complex, in addition to the technological benefits of the polymer backbone, provides novel materials with outstanding potentials to be used in a wide range of applications. Although the correlation between bulk macroscopic properties of such systems to the microscopic characteristics of the polymer precursor and transient bonds is frequently studied, the importance of coordination geometry of the metal complex is often overlooked. Despite that, the knowledge of controlling the spatial configuration of supramolecular coordination complexes (SCCs) has been extremely advanced in recent years. Notable outcomes include but are not limited to the development of highly ordered SCCs arcing from 1D nanofibers to 3D metal–organic frameworks or the advent of reversible molecular rearrangement as employed in molecular machines. This wealth of knowledge has been rarely employed in the field of polymer science, while it could provide a new approach to build highly ordered model-type networks or even induce novel structural rearrangements upon the application of external stimuli. Accordingly, we classify existing reports on the coordination geometry of MSPNs and review relevant self-sorting mechanisms of SCCs to lay out general directions for employing coordination geometry as a new design parameter in polymeric systems. [ABSTRACT FROM AUTHOR]

• Effect of CTA type on the coordinative chain transfer oligomerization of 1-decene was surveyed. • Among used CTAs, ZnEt 2 and nBuEtMg demonstrated the best performances. • A single step procedure was developed to synthesize saturated PAO-based lubricants. • The produced PAOs had KV100∼2-6 cSt and VI>140 that constitute the highest share of PAO market. • Represented catalytic systems can be outstanding alternatives to commercially employed BF 3 catalyst. Our recently developed new procedure was recalled to synthesize saturated polyalphaolefin (PAO)-based lubricants, in situ in a single step manner, using different chain transfer agents (CTA)s. To this aim, coordinative chain transfer oligomerization (CCTO) of dec-1-ene monomer was conducted to achieve saturated PAOs employing [Ti{2,2ʹ-(OC 6 H 2 -4,6-tBu 2) 2 NHMePhMeNH}Cl 2 ] complex and MAO as pre-catalyst and cocatalyst, respectively. Along with catalyst, various mole fractions of diethylzinc (ZnEt 2), triethylaluminium (TEAL), and n-butylethylmagnesium (nBuEtMg) were utilized as CTAs during oligomerization procedure. Results disclosed that ZnEt 2 lead to a reversible chain transfer reaction but TEAL, and nBuEtMg caused an irreversible chain transfer manner. Molecular weight of the synthesized PAO samples decreased by utilizing CTAs. Kinetic and 13C-NMR results exhibited that the catalyst consumption diminished and PAO tacticity degraded in CCTO procedure in comparison to the traditional oligomerization process. Furthermore, 1HNMR results confirmed the preparation of fully saturated PAO chains in the presence of proper amounts of ZnEt 2 and nBuEtMg, which reveals their high efficiency in performing the CCTO mechanism. Kinematic viscosity (KV) and viscosity index (VI) values of the fabricated samples were comparable with commercial PAOs which are traditionally produced by the dangerous BF 3 catalyst in industry. [ABSTRACT FROM AUTHOR]

Olefin block copolymers (OBCs) are new class of thermoplastic elastomers having low glass transition temperature soft blocks and highly crystalline hard blocks synthesized by reversible chain shuttling between two catalysts with considerably different comonomer responses through a chain transfer agent. Theoretical representation of kinetics and microstructure evolution in chain shuttling polymerization (CSP) is of vital importance especially since the existing characterization tools have severe limitations in retrieving the blocky nature of OBCs. In this work, we correspondingly develop an effective model to represent CSP in practical conditions and compare our predictions to the existing experimental data. We illuminate kinetics and microstructure development in both OBC chains and individual blocks. We specifically clarify the effect of varying the reversibility of transfer reactions through tuning chain shuttling agent and hydrogen concentrations on OBC chains and blocks in terms of their corresponding molecular weight and chemical composition distribution and draw guidelines for achieving OBCs with desired properties. [ABSTRACT FROM AUTHOR]

A nonlinear targeted energy transfer mechanism calledVibro-Impact Nonlinear Energy Sink (VI NES)is studied in the present work for seismic mitigation of building frames. In order to best tune VI NES parameters including clearance and stiffness ratio, the problem is formulated via an optimization framework. To form the objective function and trace the structural behavior, several seismic performance indices developed in previous works are employed. Carrying out nonlinear dynamic time history analyses on a number of low and medium-rise steel moment frames with an attached VI NES and performing Fourier analyses on the obtained structural responses, reveal a short reaction time and broadband energy dissipation in the passively controlled structure through the attached VI NES. VI NES parameters are also determined via the optimization process under the scaled earthquake time history record that has the closest spectrum to the target spectrum. The seismic performance indices are evaluated to test the trained (optimized) case under other earthquake records in the set and yield appropriate results. [ABSTRACT FROM PUBLISHER]

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease, which is caused by a multitude of mutations in genes encoding proteins of the cardiac sarcomere (1). Apical hypertrophic cardiomyopathy (AHCM) is an uncommon type of HCM. The sudden cardiac death is less likely to occur in the patients inflicted with AHCM (2). Herein, we presented the case of a 29-year-old man with AHCM, who had typical exertional chest pain without any cardiovascular risk factors, except for a sudden cardiac death in his older brother at the age of 28 years. After performing complete clinical and paraclinical evaluations, the patient underwent optimal medical treatment with beta-blocker agents without any symptoms. [ABSTRACT FROM AUTHOR]

We introduce a theoretical modelbased upon the kinetic Monte Carlo(KMC) simulation approach capable of quantifying chain shuttling copolymerization(CSP) of ethylene and 1-octene in a semibatch operation. To make adeeper understanding of kinetics and evolution of microstructure,the reversible transfer reaction is first investigated by applyingeach of the individual catalysts to the reaction media, and the competencesand shortcomings of a qualified set of CSP catalysts are discussedbased on coordinative chain transfer copolymerization (CCTP) requirements.A detailed simulation study is also provided, which reflects and comparesthe contributions of chain transfer reversibility and other chainbreaking reactions in controlling distribution fashion of molecularweight and chemical composition. The developed computer code is executedto capture developments in dead chain concentration and time-drivencomposition drift during CCTP. Also, the effect of chain shuttlingagent (CSA) on the copolymerization kinetics is theoretically studiedby simultaneous activation of both catalysts. In this way, it is attemptedto make control over comonomer incorporation in the course of copolymerization.The molecular-level criteria reflecting copolymer properties, i.e.,ethylene sequence length distribution and longest ethylene sequencelength, as the signature of CSA performance, are virtually simulatedin the presence and absence of hydrogen to capture an image on gradientcopolymers in CCTP and blocks with gradually changing compositionin CSP. [ABSTRACT FROM AUTHOR]

Introduction. Cardiovascular disease and heart failure are common in dialysis patients. Recurrent subclinical myocardial ischemia is an important event which may lead to the heart failure. We examined whether this phenomenon occurs secondary to the intradialytic hypotension in hemodialysis patients. Materials and Methods. Twelve patients prone to intradialytic hypotension who had been on maintenance hemodialysis for more than 12 months and 15 hemodialysis patients without any history of intradialytic hypotension were included in this study. Echocardiography was performed before hemodialysis (baseline), and at 60 minutes and 120 minutes during hemodialysis (climax), and 30 minutes postdialysis (recovery). Left ventricular end-diastolic diameter, left ventricular systolic diameter, left ventricular ejection fraction, fractional shortening of left ventricular, and regional wall motion abnormality score and index were measured during the four stages in all patients. Results. Regional wall motion abnormality preceded reduction in the left ventricular ejection fraction and fractional shortening in patients with intradialytic hypotension. However, decreased systolic blood pressure and increased regional wall motion abnormality were accompanied. Conclusions. This study showed that reversible myocardial dysfunction occurs during the hemodialysis. It may be contributed to the intradialytic hypotension. In addition, we showed that regional wall motion abnormality less frequently occurred in patients without intradialytic hypotension. This suggests that confronting with intradialytic hypotension may prevent cardiovascular dysfunction. [ABSTRACT FROM AUTHOR]

The association between uric acid (UA) and cardio‐metabolic conditions has been recognized for a long time. However, recently, a body of evidence has highlighted the independent role of UA in a series of conditions, including renal and cardiovascular diseases. In this light, data regarding the prognostic role of UA in acute coronary syndrome (ACS) is scarce. A total number of 100 patients, 59 males and 41 females, diagnosed with ACS were recruited in this study. At the time of admission to the hospital, the serum level of UA was measured. In addition, the HEART score was calculated based on each patients' profile. Participants were on average 61.37 ± 12.08 years old. The most prevalent risk factors were hypertension (48%), a history of coronary artery disease (40%), and diabetes mellitus (33%). The average serum level of UA was 5.81 ± 1.81 mg/dl, and the calculated HEART score had a median of six (minimum of two and maximum of ten). A positive yet statistically insignificant correlation was found between the measured UA level and the calculated HEART score (R = 0.375, p = 0.090). However, further studies with larger sample size are required to assess the direct association of UA level with major adverse cardiac events in patients with cardiovascular disease. [ABSTRACT FROM AUTHOR]

Self-healing is a nature-inspired characteristic that is imparted in synthetic polymeric materials through the integration of reversible supramolecular bonds following different design concepts. Generally, the dynamics of supramolecular bonds regulates timescale of the self-healing process, specifically in polymeric systems with a homogeneous morphology. Herein, we explore the utility of guanine as a hydrogen bonding group to construct supramolecular polymeric systems based on poly (n -butyl methacrylate). For this purpose, we follow a three-step reaction approach, including a living radical copolymerization, deprotection of the functional comonomer, and grafting of the guanine group. The microstructure of obtained samples is assessed at each step by a combination of 1H NMR, FTIR, and GPC, and the homogeneity of morphologies is realized from the lack of secondary thermal transitions in DSC thermograms. To discover scaling concepts that govern such supramolecular materials, we systematically vary the structural parameters, including the chain length and the fraction of associative groups, and investigate their responses to the oscillatory shear deformation. The relaxation dynamics becomes significantly slower upon the introduction of transient bonds, which gets even more hindered when the chain length or the fraction of supramolecular groups are increased, following the scaling laws derived from the sticky reptation mechanism. Moreover, despite rheological measurements reveal that the network recovery after large deformations is not immediate, samples could completely heal a macroscopic scratch at 40 °C within 24 h, which is promising for the development of self-healing adhesives and coatings. Image 1 • A new supramolecular polymer based on guanine hydrogen bonding group is synthesized. • Rheological properties are described based on the sticky reptation model. • Self-healing is evaluated by rheological recovery tests after large deformations. • A macroscopic surface scratch is healed at 40 °C within 24 h. [ABSTRACT FROM AUTHOR]

Unroofed coronary sinus (UCS) is an uncommon congenital heart anomaly and the most unusual type of atrial septal defect. This report presents a 71‐year‐old female with palpitation and dyspnea following an emotional stress, who was referred for ablation of typical atrial flutter. Finally diagnosed with a partially unroofed CS causing a bidirectional shunt. [ABSTRACT FROM AUTHOR]

Double network hydrogels are composed of chemical and physical bonds, whose influences on the macroscopic material properties are convoluted. To decouple these, a model dually crosslinked network with independently tunable permanent and reversible crosslinks is introduced. This is realized by interlinking linear and tetra‐arm poly(ethylenegycol) (PEG) precursors with complementary reactive terminal groups. The former also carries a terpyridine ligand at each end, which forms reversible metallo‐supramolecular bonds upon addition of metal ions. These dual networks display different types and amounts of network defects, as studied by light scattering and proton double‐quantum (DQ) NMR. Dynamic light scattering suggests that the network mesh size decreases upon introduction of metal ions, as supported by a decrease of the residual dipolar coupling constant in NMR. Static light scattering indicates larger static inhomogeneities in those networks composed of stronger ions. This is complemented by a fast solid‐like component in the DQ buildup in NMR, attributed to the formation of nanoscopic clusters of charged complexes. The DQ buildup curves also suggest that the presence of strong physical bonds increases the fraction of mobile segments, like loops and dangling ends. This combined study unveils the interplay of chemical and physical bonds toward the formation of a hierarchical structure. [ABSTRACT FROM AUTHOR]

Hydrogels are polymer networks swollen in water that are characterized by soft mechanics and high permeability. This makes them good candidates for separation and membrane technologies. The diffusion is controlled by the mesh size of the network, and this can be made tunable through the introduction of thermoresponsive polymers. However, this is still a developing field. To contribute to this development, a dual dynamic network is formed composed of four‐arm polyethylene glycol precursors in which each arm is functionalized with both a terpyridine moiety capable of forming reversible metal–ligand complexes along with branches of poly(N‐isopropylacrylamide) (pNIPAAm), which can be switched between expanded and collapsed states and therewith offers a path for switching the microscopic gel‐network mesh size, along with the macroscopic gel elasticity. The dually sensitive hydrogel has the capability of doubling its elastic modulus when going above the lower critical solution temperature (LCST) of pNIPAAm. In addition, the diffusive permeability of the hydrogel is switched upon change of temperature, whereby diffusants are trapped above the LCST of pNIPAAm. Moreover, it is possible to disassemble and reform the gel upon change of pH. With that, the hydrogel has potential application as a switchable and reversible membrane. [ABSTRACT FROM AUTHOR]

As being a hazardous and corrosive co-initiator in α-olefin oligomerization, replacement of AlCl3 with other Al-based compounds or with an environmentally friendly deep eutectic solvent (DES) was assessed. To synthetize DES, first, a 1:1.5 molar ratio mixture of glucose and urea was reacted with an equimolar mixture of ZnCl2 and distilled water. The as-synthesized DES was employed along with Al-containing precursors, AlEt3, AlEt2Cl, AlCl3, et al./DES = 2 molar ratio, in 1-decene oligomerizations to poly(α-olefin) (PAO) oils. The as-prepared PAOs were fully characterized to shed light on their microstructure and flow properties. It was found that AlEt2Cl and AlEt3, in neat from and along with DES, render low molecular weight oligomers with low KV100 (3.6–4.1 cSt). NMR results indicated that PAOs from AlEt3-DES, AlEt2Cl-DES exhibited similar amount of short chain branching (58.9 and 62.3%) compared to that obtained from the neat AlCl3 co-initiator (58.5%). The overall results affirmed that employing DES as the main ingredient of the initiating system based on AlEt2Cl and AlEt3 compounds not only provides more environmentally benign protocol by decreasing the need for hazardous and corrosive Al compound, but also it favors production of low viscosity PAOs, with KV100 ~ 4 cSt, that constitute the highest share of PAO market. These systems can be outstanding alternatives to commercially employed BF3 co-initiator. [ABSTRACT FROM AUTHOR]

Objective To revalidate the craniometric dimensions of classic posterior burr holes for ventricular catheter insertion in hydrocephalic patients, based on ideal catheter position on a 3-dimensional simulated computed tomography (CT) reconstruction model of the ventricles. Methods Fifteen patients with hydrocephaly underwent multislice, thin-cut CT to geometrically determine the Cartesian coordinates of a new point for optimal posterior ventricular catheterization. The success rate for ventricular puncture and the thickness of brain traversed by the catheter with 3 approaches (Frazier, Keen, and the suggested point) were compared. Results The suggested burr hole point for posterior ventricular catheterization is 51 and 57 mm posterior and 58 and 60 mm above the external auditory meatus parallel to the orbitomeatal plane on the right and left sides, respectively, significantly different from the classical Frazier and Keen points. The success rate was 100% for approaches using the suggested point and the Frazier point, compared with 83% using the Keen point. This 17% difference was marginally significant ( P = 0.052). The parenchymal mantle for the Frazier point was thicker than that of the suggested point on both sides, although the difference was statistically significant only on the right side ( P = 0.006). The parenchymal mantle was thinner in the Keen approach compared with the suggested approach, but the difference was not statistically significant. Conclusions The use of a suggested burr hole point for posterior ventricular catheterization may decrease the amount of parenchymal mantle of the brain transgressed by the catheter, and may marginally improve the chance of successful posterior ventricular catheterization. [ABSTRACT FROM AUTHOR]

BACKGROUND: The interventricular septal hematoma (IVSH) is a rare and potentially lethal finding. There are variously reported etiologies including instrumental damages during cardiac interventions. Although there are not enough studies available, conservative management is considered as a preferable approach in stable patients. CASE REPORT: A 45-year man smoker with the previous history of percutaneous coronary intervention (PCI), admitted with unstable angina in present visit. Coronary angiography showed significant in-stent restenosis (ISR) of the left anterior descending (LAD) artery stent. During our intervention for treatment of the ISR, the wire movement caused a diffuse dissection without any runoff, in the distal portion of the LAD. Therefore two stents were deployed in the dissected segment with a short overlapping segment. Unfortunately, the overlapping segment of these stents was located in the myocardial bridge segment. Therefore the contraction of the interventricular septum (IVS) caused a scissor-like movement of the stents, and they ruptured the LAD into the septum. Therefore, the contrast agent was accumulated in the IVS. Immediately, a graft stent was deployed in the overlapping segment of stents and perforation became sealed. In echocardiography, the IVS diameter increased to 30 mm. Since the patient was hemodynamically and electrically stable, he underwent conservative approach and after two months the septum returned to the normal size. CONCLUSION: During PCI on the LAD artery, the implantation of stents in the septal course with a short overlapping segment can result in coronary perforation and therefore IVS hematoma by the scissor effect. Septal hematoma may cause life-threatening arrhythmias or ventricular septal rupture, but if it is asymptomatic or uncomplicated. Conservative management is the best strategy. [ABSTRACT FROM AUTHOR]

Dynamic and transient shear and elongation flow experiments along with gel permeation chromatography (GPC) and differential scanning calorimetry (DSC) analysis are performed on linear low -density polyethylenes (LLDPEs) irradiated at doses below 25 kGy. GPC data indicate no changes in the molar mass distribution, and there are almost no changes in melt and crystallization temperatures, likewise. Contrary, dynamic shear rheological behavior including thermorheological complexity, type of reduced van Gurp-Palmen curves, and zero shear-rate viscosities all disclose growing levels of long-chain branching with irradiation dose. An inverse tube model is developed for binary blend of linear and star chains and used to extract the fraction of the branched components. Modeling results reveal progressive increase in the length and fraction of star chains, as evidenced by appearance of an anomalous double overshoot in the transient shear viscosities. Detection of strain hardening in extensional stress growth coefficient data, well-quantified by molecular stress function model, is also in agreement with the predictions of tube model. [ABSTRACT FROM AUTHOR]

Rheumatic fever (RF) is a prevalent healthcare problem in the developing countries. Recurrence of this disorder is often observed in childhood and adolescence. RF can mimic the presentations of infective endocarditis, and clinicians are not really familiar with this issue. Herein, we present a case of recurrent acute rheumatic fever in a patient suspicious of acute bacterial endocarditis due to her previous RF. Finally, she was definitively diagnosed and underwent valvular replacement surgery and received prophylaxis antibiotics besides regular follow-up. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus-2 raised in 2019 (COVID-19) affects the lung tissue and other organs, specifically the heart. The current study evaluated 120 hospitalised patients with severe COVID-19 between March 2021 and February 2022. Patients' demographics, vital signs, electrocardiogram abnormalities, clinical laboratory tests, including troponin I (TPI), mortality, and discharge type, were recorded. Among the 120 hospitalised patients with severe COVID-19, 54 (45.0%) patients were male, with an average age of 63.2 ± 1.4. Many patients have chronic comorbidities, including hypertension (51.6%), diabetes mellitus (34.1%), and ischemic heart disease (17.5%). The in-hospital and six months after the discharge mortality were 45.8% and 21.5%, respectively. Cardiac injury was observed in 14 (11.7%) patients with a mean TPI level of 8.386 ± 17.89 μg/L, and patients with cardiac injury had higher mortality than those without cardiac injury (P < 0.001). Furthermore, the cardiac injury was meaningfully correlated with age (ρ = 0.182, P = 0.019), history of ischemic heart disease (ρ = 0.176, P = 0.05), hospitalisation result and mortality (ρ = 0.261, P = 0.004), inpatient in ICU (ρ = 0.219, P = 0.016), and serum levels of urea (ρ = 0.244, P = 0.008) and creatinine (ρ = 0.197, P = 0.033). Additionally, the discharge results were significantly correlated with oxygen saturation with (ρ = −0.23, P = 0.02) and without (ρ = −0.3, P = 0.001) oxygen therapy, D-dimer (ρ = 0.328, P = 0.019), LDH (ρ = 0.308, P = 0.003), urea (ρ = 0.2, P = 0.03), and creatinine (ρ = 0.17, P = 0.06) levels. Elevated TPI levels are associated with increased mortality in severe COVID-19 patients. Therefore, TPI may be a beneficial biofactor for early diagnosis of cardiac injury and preventing a high mortality rate. [ABSTRACT FROM AUTHOR]

A set of MgCl2.EtOH adducts was synthesized by employing two different weight fractions of span 80 (0.5, and 1.0 wt.%) as an emulsifier during adduct preparation step by melt quenching method. Spherical morphology of the prepared adducts was explored using scanning electron microscopy. Further characterization results revealed that emulsifier containing adducts had similar crystalline structure, higher ethanol content and smaller particle sizes. Prepared adduct samples were employed in TiCl4/MgCl2 (Ziegler–Natta) catalysts synthesis which subsequently tested in slurry-phase ethylene polymerization in the presence of triethylaluminium as a cocatalyst. The ethylene polymerization results disclosed that, using emulsifier caused to high active catalyst samples in comparison with emulsifier-free one, where catalyst activity increased up to 40% by using 1.0 wt.% of emulsifier. And as a significant achievement, molecular weight results showed that, synthesized catalysts in the presence of emulsifier led to the production of ultra-high molecular weight poly ethylene with Mv > 1.5 × 106 g/mol at low ethylene pressure of only 2 bar. The production of ultra-high molecular weight poly ethylene together with small particle size feature make the catalyst containing 1 wt.% emulsifier as a good candidate for industrialization step through slurry-phase plants. [ABSTRACT FROM AUTHOR]

Nickel diimine late transition metal (LTM) and CpTiCl metallocene catalysts were supported on the TIBA-modified MgCl·nEtOH adduct, separately and concurrently, at different ratios, to yield hybrid catalysts, where the catalytic precursors were activated in the ethylene polymerization with TEA as the cocatalyst. Polymerization activities revealed that supported LTM catalysts show very high levels of activity, in an adverse trend with polymerization temperature ranging from 30 to 70 °C, in opposition to the activity of metallocene component. Consequently, the proportion of corresponding polymer fractions were tuned by changing reaction temperature as well as catalyst composition. Study of thermal properties confirmed that LTM component is responsible for production of less crystallizable branched chains, while metallocene fraction makes highly crystallizable linear chains. All samples showed noticeable thermorheological complexity due to coexistence of linear and branched microstructures. Interestingly, it was found that increase in metallocene fraction of the hybrid catalyst stalls the terminal relaxation of the produced polymers and increases the entanglement density by decreasing the extent of branching. Study of dynamic mechanical properties revealed that the intensity of β transition could be correlated with the branching level and catalyst composition accordingly. [ABSTRACT FROM AUTHOR]

It is the dual nature of chain shuttling polymerization (CSP) that makes control of olefin block copolymer (OBC) composition difficult and difficult, but at the same time, stimulating. Although recent investigations on OBCs brought some insights to the kinetics and microstructure of block copolymers differentiating from ethylene and α-olefins, some crucial features of these systems are not uncovered because of experimental difficulties. Thus, attention is still placed upon theoretical concepts that enable deeper understanding of behavior of end-of-batch OBCs. Extending the predictability of a well-developed Monte Carlo algorithm, we present for the first time an explicit image of hard-soft segmental growth at the course of CSP process. The stochastically tailored ethylene/1-octene copolymers with diverse architectural characteristics were simulated and characterized in terms of mole fraction of soft and hard segments, block length distribution, sequence length distribution, longest ethylene sequence distribution, and the distribution of the number of blocks per growing copolymer chain to be used as unique signatures of this reaction mechanism. [ABSTRACT FROM AUTHOR]

A standard Monte Carlo-based program with innovative data storage structure was developed and put into practice to tailor ethylene/1-hexene copolymers through semibatch single site metallocene catalyzed copolymerization. The distribution of copolymer composition, ethylene sequence length, longest ethylene sequence length, as well as the number-average degree of polymerization, and sequential placement of 1-hexene comonomer segments along copolymer chains were monitored and evaluated applying a computerized feeding to metallocene catalyzed ethylene/1-hexene copolymerization. In particular, bivariate copolymer composition–chain length (CC–CL) distribution was compared for two feeding recipes with uncontrolled and well-controlled comonomer insertion. The advantages of controlled feeding in comparison to uncontrolled feeding were discussed in view of aforementioned architectural features. To obtain macromolecules with tailored comonomer distributions, special feeding strategies were developed by training and examining the developed model to capture crystallization analysis fractionation (CRYSTAF) of ethylene/1-hexene chains, as a unique signature of tailored copolymers with rather narrow bivariate CC–CL distribution. The simulation results appropriately highlight the critical importance of computerized feeding with respect to uncontrolled feeding. [ABSTRACT FROM AUTHOR]

Poly(vinyl alcohol) (PVA) is a widely used synthetic polymer that is made by hydrolysis of poly(vinyl acetate) (PVAc). A significant challenge in the production of well-defined PVA arises due to the high frequency of chain transfer reactions that occur in the radical polymerization of PVAc, which limits the molecular weight and leads to branching. Upon hydrolysis of PVAc, both acetate groups and branch points can be hydrolyzed, resulting in a PVA with a significantly lower molecular weight than the parent PVAc, making control over the molecular weight distribution of PVA difficult. In this work we demonstrate the production of PVAc with a well-defined and linear structure by reversible addition-fragmentation chain transfer (RAFT) polymerization under conditions in which chain transfer is reduced. PVAc samples were prepared by suspension polymerization using both conventional free-radical polymerization and RAFT polymerization at 50 °C. When using RAFT polymerization, upon hydrolysis there was a minimal decrease of the degree of polymerization and high molecular weight PVA of low dispersity was obtained. These results demonstrate the synthesis of well-defined PVA and offers a potential route to the production of PVAc and PVA products with uniform properties. [Display omitted] • Synthesis of PVAc by conventional free-radical polymerization and RAFT suspension polymerization. • Hydrolysis of PVAc (prepared by RAFT) to PVA with a well-defined structure. • Use of RAFT suspension polymerization at 50 °C resulted to decrease of branching. • Synthesis of well-defined PVA offers a potential route to the production of PVAc and PVA products with uniform properties. [ABSTRACT FROM AUTHOR]

Background: Identifying the sources of variation in QTc measurements is important for preventing arrhythmias during and after hemodialysis. The present study was designed to determine the correlation between the type of hemodialysis buffer and the changes in QTc interval in patients on chronic hemodialysis. Methods: Fifty-nine patients on chronic hemodialysis who referred in winter 2007 to hemodialysis centers of Ghaem and Hashemi Nejad hospitals, in Mashhad, Iran, were divided into two groups according to their last dialysate buffer: acetate or bicarbonate. Electrocardiography, arterial blood gas parameters, serum K+, Na+, ionized calcium, and albumin levels were measured prior to and after hemodialysis in all patients. Results: All arterial blood gas parameters and serum electrolytes concentrations were increased except K+ levels that were significantly decreased with hemodialysis. PCO2 and QTc intervals were slightly increased in all patients, however this increase was not statistically significant. We found that the type of dialysate affected the QTc interval, HCO3, base excess, base excess of extra cellular fluid, and base buffer changes with no effect on ionized calcium, pH, PCO2, and serum albumin concentration. QTc interval was prolonged by using bicarbonate and shortened by using acetate dialysate buffer. We found no correlation between the variations of QTc interval and serum electrolytes or arterial blood gas parameters in either group. Conclusion: Bicarbonate buffer use in hemodialysis prolonged QTc interval and acetate buffer shortened it. This effect is independent of serum electrolytes and pH changes during hemodialysis. The effect of bicarbonate buffer is probably due to more tolerability of ultra filtration, more effective edema reduction and augmented body electro-conductivity. [ABSTRACT FROM AUTHOR]

Characterization of long-chain branches (LCBs) in semi-crystalline polyolefins has been a great challenge in both academia and industry. We have recently utilized a tandem catalytic system in a coordinative chain transfer polymerization, by which, upon repetitive release of growing chains as macromers and re-incorporating them, a branch-on-branch microstructure can be formed. Herein, we employ a tandem catalytic system based on a metallocene catalyst, which is capable of forming polyethylene chains with linear crystallizable sequences. Reactions conditions are varied systematically and their influence on the formation of LCB is studied through the lens of thermal analysis. Evidently, the polymerization temperature is the most influential parameter, which upon decreasing from 80 to 40 °C significantly reduces the average lamellae thickness and alters the crystal growth geometry from 3D spherulite- to 2D disk-like crystals. These results suggest thermal analysis as a sensitive method for quantifying LCBs. [ABSTRACT FROM AUTHOR]

Myocardial infarction without ST-segment elevation (NSTEMI) is considered an inflammatory disorder associated with a high mortality rate worldwide. High-sensitivity C-reactive protein (hs-CRP) is an important inflammatory marker for NSTEMI and related to cardiovascular events. Colchicine, as a potent anti-inflammatory drug, is frequently prescribed for the treatment of gout and pericarditis. The present study aimed to evaluate the effects of colchicine, as an anti-inflammatory drug, on hs-CRP levels in NSTEMI patients. We performed a randomised, double-blind, placebo-controlled trial involving 150 NSTEMI patients referred to Imam Reza and Ghaem Hospitals affiliated to Mashhad University of Medical Sciences. The patients were randomised to receive colchicine or placebo along with optimal medications for 30 days. The hs-CRP was measured at the admission and end of the study. Our results revealed that, in both colchicine and placebo groups, hs-CRP levels were significantly mitigated in NSTEMI patients compared to baseline (P < 0.001). However, the decreasing properties of colchicine on hs-CRP levels were remarkably stronger than placebo following the 30 days of treatment (P < 0.001). Nevertheless, neither colchicine nor placebo treatment could achieve hs-CRP levels lower than 2 mg/L. There were no significant differences between the effects of colchicine on the hs-CRP decrease in diabetic and non-diabetic, male and female, and normal and preserved LVEF NSTEMI patients. It can be concluded that colchicine may prevent the disease progression and succedent cardiovascular events in NSTEMI patients by attenuating the inflammation. [ABSTRACT FROM AUTHOR]

Background: Patients with Contrast-Induced-Nephropathy (CIN) are at a greater risk of in-hospital complications, longer hospitalization, and long-term mortality in comparison with those without CIN. Despite many studies on the helpful effects of statins in preventing contrast-nephropathy, there is not enough evidence comparing different statins in inhibiting CIN. So, we planned this study to compare the efficacy of rosuvastatin and atorvastatin in prevention of contrast-induced nephropathy. Methods: This was a randomized clinical trial. The efficacy of two known statins, atorvastatin and rosuvastatin were compared in prevention of CIN in patients with ST-Elevation Myocardial Infarction (STEMI) who underwent Primary Percutaneous Intervention (PPCI) between May 2015 and April 2016 in Qaem and Imam Reza hospital, Mashhad, Iran. Subjects were divided randomly to 80-mg atorvastatin or 40-mg rosuvastatin group before PPCI. Participants’ characteristics including echocardiographic, laboratory and demographic data were recorded and incidence of CIN was assessed. Results: Two hundred cases with STEMI undergoing PPCI were recruited in the study and randomized to 80-mg atorvastatin (n = 98) or 40-mg rosuvastatin (n = 102) group before PPCI. The incidence of CIN was 5.67% (n = 13) in all participants; 6.3% (n = 7) in the rosuvastatin group and 5.1% (n = 6) in the atorvastatin group. There was a significant difference between creatinine and Glomerular Filtration Rate (GFR) after 48 hours of PPCI. Creatinine was lower and GFR was higher in the rosuvastatin group (P = 0.029, P = 0.005). Conclusion: There was a little trend for prevention of CIN in patients after PPCI in rosuvastatin group compared to atorvastatin group, in full dose. However, this preference was not clinically relevant. [ABSTRACT FROM AUTHOR]

Platelet activation and aggregation play a major role in thrombosis formation of coronary arteries in patients with Acute Coronary Syndrome (ACS) and is responsible for most ischemic complications during PCI. There is little information on the benefits and side effects of intracoronary and intravenous injection of Eptifibatide, a potent antiplatelet agent; therefore, this study was performed with the aim to compare coronary blood flow velocity by measurement of TIMI frame count. In intravenous versus intracoronary bolus administration of Eptifibatide during PCI in ACS patients. This non-randomized clinical trial study was performed on 103 patients with acute coronary syndromes who referred to the cardiac emergency ward of Ghaem hospital, Mashhad University of Medical Sciences, and were candidates for urgent coronary angiography and PCI. Forty-eight cases received intracoronary bolus Eptifibatide and 55 intravenous Eptifibatide. TIMI Frame Count and Corrected TIMI Frame Count were used to comparing the effect of these two methods on coronary blood flow velocity. Data were analyzed by SPSS software (version 22). To compare the quantitative variables in the two groups, according to the distribution of variables, the t-test was used if it was normal or the Mann-Whitney test was used if it was not normal. A Chi-square test was also used to compare qualitative variables into two groups. P<0.05 was considered statistically significant. Mean of age, gender, and cardiovascular risk factors were similar in the two groups. There was no significant difference in terms of serum Creatine Kinase MB (CKMB) level, Left Ventricular Ejection Fraction (LVEF), coronary artery lesion length, coronary artery diameter, coronary thrombosis, and coronary artery thrombectomy in two groups. Based on Student's t-test, there was no significant difference between mean TIMI Frame Count in different coronary arteries in the intracoronary and intravenous injection groups (In LAD, P=0.518; For LCX, P=0.576; and in RCA, P=0.964). The complications were observed in 11 patients (22.9%) of the intracoronary injection group and 9 (16.4%) of the intravenous injection group; the difference was not significant (P=0.402). The effects and complications of Eptifibatide were not significantly different in Intracoronary and intravenous administration in ACS patients during PCI and at the time of patients' hospitalization. [ABSTRACT FROM AUTHOR]

The reactive co‐polymer approach is one of the most promising techniques for the synthesis of functional polyolefins. Following this concept, 1‐hexene and p‐methylstyrene are co‐polymerized in the presence of a generic Brookhart‐type catalyst. The microstructures of the co‐polymers imply the tendency of p‐methylstyrene co‐monomers to place at the end of the structural branches formed by the chain walking reaction. The molar masses of the co‐polymers decrease, not only at higher levels of co‐monomer but surprisingly by decreasing reaction temperature. A mechanism consisting of a highly stable η3 metal–benzyl intermediate, which is quantitatively approved by density functional theory calculations, can delicately justify all the aforementioned observations. A series of the produced co‐polymers is selectively functionalized by maleic anhydride at the benzylic position of p‐methylstyrene, under very mild reaction conditions. Such a reactive intermediate opens the path for the introduction of different types of functionalities in polyolefins. Namely, the grafted co‐polymers were further functionalized by a triazole ring, which provides a transient supramolecular network through intermolecular hydrogen bonding. [ABSTRACT FROM AUTHOR]

The patient was a 19 year-old woman with the diagnosis of resistant hypertension, although she was under treatment of three classes of anti-hypertensive drugs (beta blocker, angiotensin receptor blocker, diuretic) for more than one year. In physical examination there was only a significant difference between the systolic blood pressure of upper and lower extremities (200 vs. 120 mmHg), without any other remarkable finding. Three different imaging modalities (echocardiography (Figure 1), CT angiography (Figure 2), conventional aortography (Figure 3) confirmed the aortic coarctation at 30 mm after left subclavian artery origin, with the 3.5-4 mm diameter of the narrowest segment. She underwent implantation of a self-expanding aortic stent and therefore the systolic pressure gradient decreased from 90 to 15 mmHg. After three months, her blood pressure was stable on 110/80 mmHg, while she received only metoprolol 25 mg twice daily and follow-up echocardiography showed 15-20 mmHg pressure gradient through the stent. [ABSTRACT FROM AUTHOR]

Background: In-stent restenosis (ISR) is one adverse outcome of coronary stent implantation. Although using drug-eluting stents has reduced the rate of ISR, it remains a major problem. Here, we have investigated the relationship between several patient characteristics including serum high sensitive C-reactive protein (hs-CRP) and ISR.Methods: This was a case-control study comprising 104 individuals with ISR and 202 patients without. Baseline characteristics were collected using a questionnaire. Fasting blood glucose (FBG), serum triglycerides (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and serum high sensitivity C-reactive protein (hs-CRP) were measured using commercial kits on an auto-analyzer. Data were analyzed using SPSS software and a p value ≤ 0.05 was considered significant.Results: Diabetes mellitus (p < 0.001), stent type (p = 0.005), serum hs-CRP (p = 0.006), FBG (p = 0.038) and serum TG (p = 0.039) were significantly associated with ISR. The association between hs-CRP and ISR remained significant after adjustment for stent type and DM. For patients with a serum hs-CRP <2.64 mg/dL, ISR was only associated with diabetes mellitus (p = 0.016); while for individuals with a serum hs-CRP ≥2.64 mg/dL, ISR was also associated with the presence of diabetes mellitus, serum triglycerides and stent type.Conclusion: Higher levels of serum hs-CRP were significantly associated with the occurrence of ISR. [ABSTRACT FROM AUTHOR]

Background: Remote ischemic preconditioning (RIPC) is a simple non-invasive method by using cycles of ischemia and reperfusion on a remote organ. Objective: To determine the effect of RIPC outcomes in patients with ST-segment-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). Methods: This double blind randomized clinical trial was conducted in two teaching and reference hospitals in Mashhad, Iran. Sixty patients with acute STEMI were enrolled from October 2018 to January 2019. The patients were allocated into two groups, by using sealed envelope randomization i.e., a study group of patients who had undergone RIPC intervention and a control group of patients who had not undergone RIPC. Half an hour before PPCI, a sphygmomanometer cuff was placed around the left upper arm and inflated up to 200mmHg for five minutes; then the cuff was deflated for another five minutes, and this cycle was repeated 3 times before or during PPCI. Corrected Thrombolysis in Myocardial Infarction (TIMI) frame count, ST-segment resolution, reperfusion arrhythmias and contrast induced nephropathy (CIN) were evaluated in both groups after PPCI. Study data was analyzed by SPSS version 16. Results: A total number of 26 males and 14 females were studied in study groups (n=20 for each). Both groups were homogenous according to their baseline characteristics. Both TIMI grade and Corrected Thrombolysis in Myocardial Infarction Frame Count CTFC significantly improved after RIPC (p=0.001 and p<0.0001 respectively). Moreover, CIN and reperfusion arrhythmias were reduced in the intervention group (p=0.028 and p=0.016 respectively). Also, ST-segment resolution was significantly different among groups (p=0.002). After adjusting for baseline factors only a significant relationship was observed between performing intervention and final TIMI grade (OR=26.416, 95% CI for OR=1.063, 656.184, p=0.046). Conclusion: RIPC can effectively reduce CIN and reperfusion arrhythmias in patients undergoing PPCI. Also, RIPC improved ST segment resolution and TIMI flow grade, and corrected TIMI frame count. Based on our results, RIPC may have a protective effect of on PPCI outcomes. [ABSTRACT FROM AUTHOR]

Abstract The rheological spectra of poly(n-butyl acrylate) in the presence of a series of P(nBA- b -HEMA) rheology modifiers show a two-step relaxation process originating from the PnBA matrix and the self-assemblies. The HEMA segments are further grafted with strong, hydrogen bonding UPy groups, which both magnifies and slows down the relaxation of the assemblies. The extents of associations are enlightened by studying thermal transitions in DSC, morphological developments by SAXS, and description of rheological properties using a tube-based model. It is revealed that a weak association tendency, due to long hydrophobic blocks, leads to the formation of double-linear or star assemblies, while increasing the association strength results in the formation of micelles. In an optimum block length and UPy content, loosely entangled diblock additives can form an interconnected micellar network with significantly long relaxation time. Graphical abstract Supramolecular block copolymers can form binary-linear, star-like, or even micellar assemblies in the matrix of a nonassociative polymer and can therefore significantly postpone the terminal relaxation depending on their microstructure and consequent aggregation tendencies. Unlabelled Image [ABSTRACT FROM AUTHOR]

[Display omitted] • A piezoresistive sensor is developed based on CNT-filled EVA/LDPE blend foams. • The countereffect of crosslinking and crystallinity on foam density is evaluated. • The correlation of mechanical and electrical properties with foam density is studied. • The dispersion and affinity of CNT in optimized formulations are studied. • The least mechanical and electrical hysteresis are obtained in foams with uniformly dispersed small cells. Conductive polymer composites (CPCs) with piezoresistive properties are smart detecting systems with high sensitivity, fast response, and low energy consumption. To enhance their sensitivity and cope with their high filler content requirements, solid CPCs are normally transformed into blends and foams, which reduces the elastic modulus, enabling larger deformations, wider detection range, and increased sensitivity. However, providing reversible and durable sensing properties remains challenging as it depends on the phase morphology, foam cell structure, and particle dispersion. To this end, we use multi-walled carbon nanotube (MWCNT) as a conductive filler with a high aspect ratio and develop CNT-filled ethylene vinyl acetate/low-density polyethylene (EVA/LDPE) blend foams. We fix the foam structure using chemical foaming and crosslinking agents in a compression molding process. To optimize the piezoresistive behavior, we follow a step-wise tuning approach, studying the blending morphology, the foaming attributes, the particle dispersion and affinity, thereby selecting the most promising formulations for further investigations. The least mechanical and electrical hysteresis is obtained at minimum foam density, which is obtained at a compromised crystallinity and crosslinking density. The higher affinity of MWCNT to EVA and the faster crosslinking of the EVA phase results in uniformly dispersed small cells at EVA-rich formulations and 4 phr MWCNT content. The final foam sensor demonstrates an impressive response and recovery times of less than 200 ms and remarkable durability thanks to the optimized cell morphology and mechanical properties. These findings expand the application of carbon-filled polyolefin foams in pressure monitoring, particularly in wearable sensors for strain and motion sensing. [ABSTRACT FROM AUTHOR]