Tuning of the magneto-caloric effects in Ni43Mn46In11magnetic shape memory alloys by substitution of boron.

In this study, we report the structural, magnetic, and magnetocaloric properties of B substitution on the Mn site in Ni43Mn46-xBxIn11(x= 0.5, 1.0) Heusler alloys. Crystal structure analysis using room-temperature x-ray diffraction data reveals both samples have mixed phases composed of cubic and tetragonal phases. The structural and magnetic phase transition characteristic temperatures are determined using differential scanning calorimetry, isothermal magnetization (MT), and isofield magnetization (MH) measurements. Both alloys exhibit inverse and direct magnetocaloric effects in the vicinity of their magnetostructural transition and Curie temperature (TC), respectively. For Ni43Mn45.0B1.0In11a maximum magnetic entropy change of 25.06 J kg-1K-1is observed at 250 K for a magnetic field change of 5 T.

Increased triglyceride-glucose index predicts contrast-induced nephropathy in non-diabetic NSTEMI patients: A prospective study.

The triglyceride-glucose (TyG) index is a new reliable marker of insulin resistance (IR) and has recently been reported to be associated with renal dysfunction and contrast-induced nephropathy (CIN). Our aim in this study is to investigate the relationship between the TyG index and CIN in non-diabetic non-ST elevation acute myocardial infarction (NSTEMI) patients. The study included 272 non-diabetic patients who applied with NSTEMI and underwent coronary angiography (CAG). Patient data were divided into quartiles according to the TyG index: Q1: TyG < 8.55; Q2: 8.55 ≤ TyG ≤ 8.87; Q3: 8.88 ≤ TyG ≤ 9.29; and Q4: TyG > 9.29. Baseline characteristics, laboratory measurements, angiography data, and the incidence of CIN were compared between the groups. CIN was observed in 18 (6.6%) patients in the study. The incidence of CIN was lowest in the Q1 group and highest in the Q4 group (1 (1.5%) in Q1; 3 (4.4%) in Q2; 5 (7.4%) in Q3; 9 (13.2%) in Q4; p = 0.040). TyG index was found to be an independent risk factor for the development of CIN in multivariate logistic regression analysis (odds ratio = 6.58; confidence interval (CI) = 2.12-20.40; p = 0.001). TyG index value of 9.17 was identified as an effective cut-off point for the prediction of CIN (Area under the curve: 0.712, CI: 0.590-0.834, p = 0.003), and it had a sensitivity of 61% and a specificity of 72%. The results of this study showed that a high TyG index increases the incidence of CIN after CAG in non-diabetic NSTEMI patients and is an independent risk factor for the development of CIN.

The effect of insulin resistance on the heart rate recovery in healthy individuals with a low-to-moderate cardiovascular disease risk profile.

The association between insulin resistance (IR) and heart rate recovery index (HRRI) has been reported previously, but the cardiovascular disease (CVD) risk profile of the subjects was unclear in these studies. Therefore, we evaluated the association between IR and HRRI in apparently healthy individuals without metabolic syndrome who had a low-to-moderate CVD risk profile. A total of 182 eligible subjects were retrospectively included in the study. The subjects were divided into two groups according to the homeostasis model assessment of IR (HOMA-IR) value. HOMA-IR ≥2.5 was defined as IR (+) group (92 subjects), and <2.5 as IR (-) group (88 subjects). HRRI-2 was found by subtracting the heart rate at the second minute in the post-exercise recovery period from the maximum heart rate. Abnormal HRRI was defined as HRRI-2 that is ≤42 beats. The mean age of the patients was 41.91 ± 8.64 and 49.4% of them were female. Abnormal HRRI rates were significantly higher in the IR (+) group (37.2% vs 18.2%; p = 0.004). A negative correlation was detected between HRRI-2 and HOMA-IR (r = -0.416; p < 0.001). HOMA-IR (Odds Ratio (OR) = 1.57; confidence interval (CI) = 1.10-2.23; p = 0.013) and maximum heart rate during exercise (OR = 0.95; CI = 0.91-0.99; p = 0.013) as independent variables of abnormal HRRI. The HOMA-IR value of 2.82 was identified as an effective cutoff point for the prediction of abnormal HRRI (area under the curve: 0.658; CI: 0.570-0.746; p = 0.001). In this study, it was shown that IR without metabolic syndrome reduces HRRI in healthy individuals with a low-to-moderate CVD risk profile.

Tuning the Coexistence Regime of Incomplete and Tubular Skyrmions in Ferromagnetic/Ferrimagnetic/Ferromagnetic Trilayers.

The development of skyrmionic devices requires a suitable tuning of material parameters to stabilize skyrmions and control their density. It has been demonstrated recently that different skyrmion types can be simultaneously stabilized at room temperature in heterostructures involving ferromagnets, ferrimagnets, and heavy metals, offering a new platform of coding binary information in the type of skyrmion instead of the presence/absence of skyrmions. Here, we tune the energy landscape of the two skyrmion types in such heterostructures by engineering the geometrical and material parameters of the individual layers. We find that a fine adjustment of the ferromagnetic layer thickness, and thus its magnetic anisotropy, allows the trilayer system to support either one of the skyrmion types or the coexistence of both and with varying densities.

Identification of subclinical myocardial dysfunction by Speckle Tracking Imaging in patients with myocardial infarction with non-occlusive coronary arteries (MINOCA).

PURPOSE: The objective of this study was to investigate subclinical left ventricular dysfunction in patients diagnosed with myocardial infarction with non-occlusive coronary arteries (MINOCA). METHODS: Thirty-five patients with MINOCA (average age 54.26 ± 12.24 years) and thirty-five patients with ischemia with non-obstructed coronary artery disease (INOCA) (average age 55.20 ± 8.36 years) were enrolled in the study. All clinical conditions that could affect left ventricular functions were considered exclusion criteria. Echocardiographic studies were conducted in the patient and control groups in the left lateral decubitus position using a medical ultrasound device (EPIQ 7, Philips Medical System, USA). The left ventricle was examined longitudinally with apical images of chamber 4-3-2 using the available software (QLAB 6.0). RESULTS: There were no differences in age, blood pressure level, baseline echocardiogram measurements, and tissue Doppler parameters between the two groups. In two-dimensional speckle tracking echocardiography (2D-STE) measurements, left ventricular longitudinal strain and strain rate in systole, early and late diastole from apical 4-3-2 chamber and global measurements of each parameter were significantly decreased in the MINOCA group compared to the INOCA group (p < 0.05). A significant negative correlation was observed between the global longitudinal strain rate and the troponin I in the MINOCA patients group (r=-0.43 p = 0.009). CONCLUSIONS: Our study showed that while standard echocardiographic parameters for patients diagnosed with MINOCA were normal, their left ventricular systolic and diastolic functions were reduced by the 2D-STE method.

Hidden danger of COVID-19 outbreak: evaluation of subclinical myocardial dysfunction in patients with mild symptoms.

The COVID-19 infection, which is caused by the novel coronavirus SARS-CoV-2, has rapidly emerged as a global public health issue. Cardiac complications secondary to this infection are common and associated with mortality. This study aimed to evaluate whether subclinical myocardial dysfunction exists in non-hospitalized mildly symptomatic COVID-19 patients using left ventricular global longitudinal strain (LVGLS). In this cross-sectional, single-center study, data were collected from non-hospitalized mildly symptomatic COVID-19 patients between January 01 and February 01, 2021. Fifty (26 male, 24 female) COVID-19 patients and 50 age- and sex-matched healthy volunteers were included in the study. Apical four-, three-, and two-chamber images were analyzed longitudinally by conventional methods and speckle tracking echocardiography (STE) for left ventricle functions. The mean age of the COVID-19 patients was 39.5 ± 8.96, and 52% of them were male. The most prevalent presenting symptoms were fever [in 34 (68%)], asthenia [in 30 (60%)], loss of appetite [in 21 (42%)], myalgia [in 20 (40%)], and cough [in 13 (26%)]. Plasma levels of C-reactive protein (CRP) were significantly higher in the COVID-19 patients than in the controls (10.84 ± 12.44 vs. 4.50 ± 2.81, p < 0.001). There was no significant difference between the groups in terms of standard echocardiography and Doppler parameters (p > 0.05). Left ventricular longitudinal strain and strain velocity parameters were significantly decreased in COVID-19 patients compared to healthy individuals. LV-GLS values (- 21.72 ± 3.85% vs. - 23.11 ± 4.16%; p = 0.003) were significantly lower in COVID-19 patients compared with the healthy controls. Mildly symptomatic COVID-19 patients also have subclinical myocardial dysfunction similar to hospitalized patients. STE has the potential for detecting subclinical LV systolic dysfunction, and can provide useful information regarding cardiac status in mildly symptomatic COVID-19 population.

Dynamic changes in aortic stiffness after substantial weight loss by laparoscopic sleeve gastrectomy in patients with obesity: a 1-year follow-up study.

Arterial stiffness has been identified as a powerful and independent risk factor for cardiovascular disease. Obesity is associated with an increased risk of aortic stiffness (AS) and adverse cardiovascular events. Herein, we aimed to evaluate the effects of weight loss after laparoscopic sleeve gastrectomy (LSG) on AS in individuals with morbid obesity by using the transthoracic echocardiography (TTE).A total of 53 patients with obesity (17 males, 36 females) who underwent LSG and did not have any known heart disease were included in the study. The AS parameters were measured with TTE. The demographic and echocardiographic data of the patients were studied before, at 1 month and 12 months after surgery.The mean age of the study group was 34.41±11.62, 68% of whom were female. There were no significant differences in terms of the standard echocardiography and Doppler measurements as compared with preoperative values (all p>0.05). When the elastic parameters of the aorta were compared, no significant differences were detected regarding aortic strain (%) ((16.28±4.11) vs (16.68±4.56), p=(0.998)), distensibility (cm2/dyn) ((6.74±1.78) vs (7.03±2.31), p=(0.997)) and Aortic Stiffness Index values ((10.73±3.84) vs (10.63±3.34), p=0.998) between baseline and first month after surgery. In the 12-month follow-up, it was determined that the aortic strain ((16.28±4.11) vs (22.74±5.79), p≤0.001) and distensibility ((6.74±1.78) vs (10.34±3.059), p<0.001)) values increased at significant levels.Weight loss by LSG improves arterial stiffness parameters in patients with obesity over a 1-year follow-up.

Mapping the Structure of Oxygen-Doped Wurtzite Aluminum Nitride Coatings from Ab Initio Random Structure Search and Experiments.

Machine learning is changing how we design and interpret experiments in materials science. In this work, we show how unsupervised learning, combined with ab initio random structure searching, improves our understanding of structural metastability in multicomponent alloys. We focus on the case of Al-O-N alloys where the formation of aluminum vacancies in wurtzite AlN upon the incorporation of substitutional oxygen can be seen as a general mechanism of solids where crystal symmetry is reduced to stabilize defects. The ideal AlN wurtzite crystal structure occupation cannot be matched due to the presence of an aliovalent hetero-element into the structure. The traditional interpretation of the c-lattice shrinkage in sputter-deposited Al-O-N films from X-ray diffraction (XRD) experiments suggests the existence of a solubility limit at 8 at % oxygen content. Here, we show that such naive interpretation is misleading. We support XRD data with accurate ab initio modeling and dimensionality reduction on advanced structural descriptors to map structure-property relationships. No signs of a possible solubility limit are found. Instead, the presence of a wide range of non-equilibrium oxygen-rich defective structures emerging at increasing oxygen contents suggests that the formation of grain boundaries is the most plausible mechanism responsible for the lattice shrinkage measured in Al-O-N sputtered films. We further confirm our hypothesis using positron annihilation lifetime spectroscopy.

Coexistence of distinct skyrmion phases observed in hybrid ferromagnetic/ferrimagnetic multilayers.

Materials hosting magnetic skyrmions at room temperature could enable compact and energetically-efficient storage such as racetrack memories, where information is coded by the presence/absence of skyrmions forming a moving chain through the device. The skyrmion Hall effect leading to their annihilation at the racetrack edges can be suppressed, for example, by antiferromagnetically-coupled skyrmions. However, avoiding modifications of the inter-skyrmion distances remains challenging. As a solution, a chain of bits could also be encoded by two different solitons, such as a skyrmion and a chiral bobber, with the limitation that it has solely been realized in B20-type materials at low temperatures. Here, we demonstrate that a hybrid ferro/ferri/ferromagnetic multilayer system can host two distinct skyrmion phases at room temperature, namely tubular and partial skyrmions. Furthermore, the tubular skyrmion can be converted into a partial skyrmion. Such systems may serve as a platform for designing memory applications using distinct skyrmion types.

Use of Embolectomy With Local Anesthesia for Anticoagulation Failure in Radial Artery Thrombosis.

OBJECTIVE: Although prevention of radial artery thrombosis and cardiac complications after interventions using radial access is well investigated, there is yet no clinical study that completely evaluated access-related complications. However, there is still no consensus on what exact treatment should be used in these patients. In clinical practice, analgesic, anticoagulant, and antiplatelet treatments usually improve symptoms in patients with pain; however, in some patients, complaints may persist and may not respond to these treatments. In these patients, low-risk embolectomy with a small skin incision may be beneficial. METHODS: A total of 102 patients with radial artery thrombosis after cardiac catheterization were included in the study between 2016 March and 2018 December. After the patients' initial evaluation, anticoagulation with enoxaparin or tinzaparin and antiplatelet therapy with acetylsalicylic acid and oral/local analgesic/anti-inflammatory and local anesthetic therapy were administered for 1 month. Patients whose symptoms resolved after medical treatment were followed up as outpatients. Embolectomy was performed in consenting patients who did not respond to the medical treatment. RESULTS: Of 102 patients included in the study, 33 underwent embolectomy, whereas 69 received only medical treatment. None of the patients experienced any complications, morbidity, or mortality in the peroperative period and during the medical treatment. The pretreatment symptom scores of patients who actively use their hands in daily life and profession were significantly higher than the scores of patients who are relatively less active (P = .013). Pretreatment symptom scores were negatively correlated with age (r = -0.584); symptom scores increased significantly with the decrease of patient age. No benefit from medical treatment and need for surgery was significantly greater in patients who are younger and use their hands actively in daily life and profession (P = .028). The decrease in symptom scores after treatment was significantly greater in the surgical group than in the medical group (P = .003). CONCLUSION: Radial access should be exercised with care in patients who may develop significant thrombosis-related complaints and it is necessary to decide whether radial access is essential. If patients have ongoing symptoms despite medical treatment, embolectomy can be considered as a treatment option.

Tunable Magnetic Vortex Dynamics in Ion-Implanted Permalloy Disks.

Nanoscale, low-phase-noise, tunable transmitter-receiver links are key for enabling the progress of wireless communication. We demonstrate that vortex-based spin-torque nano-oscillators, which are intrinsically low-noise devices because of their topologically protected magnetic structure, can achieve frequency tunability when submitted to local ion implantation. In the experiments presented here, the gyrotropic mode is excited with spin-polarized alternating currents and anisotropic magnetoresistance measurements yield discrete frequencies from a single device. Indeed, chromium-implanted regions of permalloy disks exhibit different saturation magnetization than neighboring, non-irradiated areas, and thus different resonance frequency, corresponding to the specific area where the core is gyrating. Our study proves that such devices can be fabricated without the need for further lithographical steps, suggesting ion irradiation can be a viable and cost-effective fabrication method for densely packed networks of oscillators.

Ion-Irradiation-Induced Cobalt/Cobalt Oxide Heterostructures: Printing 3D Interfaces.

Interfaces separating ferromagnetic (FM) layers from non-ferromagnetic layers offer unique properties due to spin-orbit coupling and symmetry breaking, yielding effects such as exchange bias, perpendicular magnetic anisotropy, spin-pumping, spin-transfer torques, and conversion between charge and spin currents and vice versa. These interfacial phenomena play crucial roles in magnetic data storage and transfer applications, which require the formation of FM nanostructures embedded in non-ferromagnetic matrices. Here, we investigate the possibility of creating such nanostructures by ion irradiation. We study the effect of lateral confinement on the ion-irradiation-induced reduction of nonmagnetic metal oxides (e.g., antiferro- or paramagnetic) to form ferromagnetic metals. Our findings are later exploited to form three-dimensional magnetic interfaces between Co, CoO, and Pt by spatial-selective irradiation of CoO/Pt multilayers. We demonstrate that the mechanical displacement of O atoms plays a crucial role in the reduction from insulating, non-ferromagnetic cobalt oxides to metallic cobalt. Metallic cobalt yields both perpendicular magnetic anisotropy in the generated Co/Pt nanostructures and, at low temperatures, exchange bias at vertical interfaces between Co and CoO. If pushed to the limit of ion-irradiation technology, this approach could, in principle, enable the creation of densely packed, atomic-scale ferromagnetic point-contact spin-torque oscillator (STO) networks or conductive channels for current-confined-path-based current perpendicular-to-plane giant magnetoresistance read heads.

A catastrophic nightmare of the interventional cardiologist: Iatrogenic left main artery dissection and longitudinal stent deformation.

Iatrogenic left main coronary artery dissection is a rare but potentially life-threatening complication of invasive coronary procedures. The newer generation drug eluting stents have shown a greater safety and efficacy compared to first generation drug eluting stents. We report a 60-year-old woman with iatrogenic left main coronary artery dissection who failed bailout stenting and underwent coronary artery bypass grafting. The strategy for managing left main coronary artery dissection is variable and depends upon the mechanism, the comorbidities of the patient and degree of hemodynamic stability. Longitudinal stent deformation is a rarely encountered complication but can be seen in complex lesions such as ostial, bifurcation and left main coronary artery lesions. The interventionists must be aware of this complication.