A case of acute myocardial infarction in paced rhythm. Utility of the Barcelona algorithm.

We describe the case of a 70-year-old man with a pacemaker implant who presented to us with atypical chest pain. His admission ECG did not satisfy the criteria for myocardial infarction according to standard Sgarbossa criteria, and Smith modified Sgarbossa criteria. However, we applied the recently developed Barcelona algorithm, which is used to diagnose acute myocardial infarction in the presence of intrinsic left bundle branch block.Electrocardiographic criteria for an acute myocardial infarction were met. Lead V6 displayed a low voltage QRS complex (3 mm) with 1 mm ST depression, satisfying the Barcelona criteria for acute myocardial infarction. He underwent primary angioplasty for critical in-stent restenosis of the left anterior descending coronary artery. This is the first case report, to the best of our knowledge, where Barcelona algorithm has been used to diagnose acute coronary syndrome in right-ventricular paced rhythm.

Complex magnetic properties associated with competing local and itinerant magnetism in [Formula: see text].

Ternary intermetallic compound [Formula: see text] has been synthesized in single phase and characterized by x-ray diffraction, scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM-EDX) analysis, magnetization, heat capacity, neutron diffraction and muon spin rotation/relaxation ([Formula: see text]SR) measurements. The polycrystalline compound was synthesized in single phase by introducing necessary vacancies in Co/Si sites. Magnetic, heat capacity, and zero-field neutron diffraction studies reveal that the system undergoes magnetic transition below [Formula: see text]4 K. Neutron diffraction measurement further reveals that the magnetic ordering is antiferromagnetic in nature with an weak ordered moment. The high temperature magnetic phase has been attributed to glassy in nature consisting of ferromagnetic clusters of itinerant (3d) Co moments as evident by the development of internal field in zero-field [Formula: see text]SR below 50 K. The density-functional theory (DFT) calculations suggest that the low temperature magnetic transition is associated with antiferromagnetic coupling between Pr 4f and Co 3d spins. Pr moments show spin fluctuation along with unconventional orbital moment quenching due to crystal field. The evolution of the symmetry and the crystalline electric field environment of Pr-ions are also studied and compared theoretically between the elemental Pr and when it is coupled with other elements such as Co. The localized moment of Pr 4f and itinerant moment of Co 3d compete with each other below [Formula: see text]20 K resulting in an unusual temperature dependence of magnetic coercivity in the system.

Studies on magnetocaloric effect of Tb2Ni0.90Si2.94 compound.

A comparative study has been carried out on the magnetocaloric properties of as-cast and annealed Tb2Ni0.90Si2.94 intermetallic compound. While the as-cast material exhibits ferromagnetic cluster-glass behaviour below 9.9 K coexisting with antiferromagnetic (AFM) interaction, the annealed system shows AFM ordering below 13.5 K and spin freezing occurs below 4 K. The compound exhibits moderate magnetocaloric performance with maximum isothermal entropy changes (-ΔS M) 8.8 and 10.9 J kg-1 K-1, relative cooling power (RCP) 306 and 365 J kg-1, along with adiabatic temperature change (ΔT ad) 5.5 and 8.15 K for 70 kOe magnetic field change in as-cast and annealed forms, respectively. The estimated magnetic entropy change is found to be larger for annealed sample in comparison to that of as-cast analogue. However, the full width at half maxima (FWHM) of -ΔS M(T) behaviour is larger in as-cast compound due to the presence of inherent structural disorder which reduces with thermal annealing. A positive isothermal entropy change (-ΔS M) and adiabatic temperature change (ΔT ad) is observed for the as-cast compound in the measured field and temperature region. In contrast, the annealed system exhibits inverse magnetocaloric effect in the low field and temperature region where AFM interactions dominate. Magnetocaloric effect (MCE) is used as a tool to establish a subtle correlation between the observed magnetocaloric effect and the reported magnetic properties of the system.

Physical properties of RIr3 (R = Gd, Tb, Ho) compounds with coexisting polymorphic phases.

The binary compounds GdIr3, TbIr3 and HoIr3 are synthesized successfully and found to form with macroscopic co-existence of two polymorphic phases: AuBe5 (C15b) and AuCu3-type. The dc magnetization and heat capacity studies confirm that the C15b phase orders ferromagnetically, whereas the AuCu3 phase remains paramagnetic down to 2 K. The frequency dependent ac-susceptibility data, time dependent magnetic relaxation behavior and magnetic memory effect studies suggest that TbIr3 and HoIr3 are cannonical spin-glass systems, but no glassy feature could be found in GdIr3. The critical behavior of all three compounds has been investigated using the magnetization and heat capacity measurements around the transition temperature (TC). The critical exponents α, ß, γ and δ have been estimated using different techniques such as the Arrott-Noakes plot, Kouvel-Fisher plot and critical isotherm as well as analysis of specific heat data and study of magnetocaloric effect. The critical analysis study identifies the type of universal magnetic class in which the three compounds belong.

Effect of Si substitution in ferromagnetic Pr2Fe17: a magnetocaloric material with zero thermal expansion operative at high temperature.

This article deals with the magnetic and thermal expansion properties of Pr2Fe16Si. This compound has been well characterized from the structural point of view by analysing X-ray diffraction (XRD) patterns. The temperature dependent behaviour of magnetization (M) and the structural parameters (lattice parameters, unit cell volume) suggest that the compound undergoes a second order phase transition from a paramagnetic to a ferromagnetic state at TC = 390 K, driven by an increase in bond length between iron atoms at 6c sites. The field-dependent behaviour of M below TC, and comparatively lower value of coercivity (Hc) have been explained by the role of Si atoms as pinning centres. In the ferromagnetic phase, the system is found to behave like an inhomogenous mean field system. The study of thermal expansion properties establishes that the compound is a zero thermal expansion material (αv = 5.3 × 10-6 K-1) operative in the temperature range T = 200-340 K. As a magnetocaloric material, Pr2Fe16Si possesses high RCP (87 J kg-1 at µ0H = 1.5 T), high operating temperature (390 K) and moderate |ΔSM|max.

Unusual bidirectional frequency dependence of dynamical susceptibility in hexagonal intermetallic Pr2Ni0.95Si2.95.

In this study, the synthesis of a novel ternary intermetallic compound Pr2Ni0.95Si2.95 forming in single phase only by deliberately introducing vacancies in Ni/Si site is reported. The detailed studies on dc magnetization, heat capacity, ac magnetization & associated dynamical scaling, different types of non-equilibrium dynamical behaviour, viz., magnetic relaxation behaviour as a function of wait time and temperature, aging phenomena, and magnetic memory effect firmly establish that the compound exhibits spin freezing behaviour below 3.3 K (Tf). However, below Tf, temperature dependence of ac susceptibility data exhibit an additional peak that shows reverse frequency dependence to that generally observed in a glassy system. The unusual bidirectional frequency dependence in a single magnetic system is of significant interest and rarely reported in literature. Competing exchange interaction arising from c/a ~ 1 and crystallographic randomness driven magnetic phase separation has been argued to be responsible for such observation. The reverse frequency shift of the low temperature peak has been described on the basis of a simple phenomenological model proposed in this work.

Transverse vibration driven large uniaxial negative and zero thermal expansion in boron bridged REPt3B framework materials.

In this work anomalous uniaxial thermal expansion behaviour at low temperatures along the c-direction of the tetragonal phase of different members of the antiperovskite REPt3B (RE = Sm, Gd-Tm) compounds is reported. Negative or zero thermal expansion (NTE/ZTE) behaviour in these compounds arises due to the transverse vibration of boron atoms in the linear Pt-B-Pt linkage. The coefficient of thermal expansion along the c-axis tends to become more negative in annealed compounds in comparison to those estimated for as-cast samples. While the as-cast TmPt3B and HoPt3B exhibit essentially ZTE behaviour, the NTE coefficient of annealed GdPt3B (∼-28 ppm K-1) is found to be even larger than that of the well known framework material ZrW2O8 (∼-9 ppm K-1) reported in the literature.

Observation of short range order driven large refrigerant capacity in chemically disordered single phase compound Dy2Ni0.87Si2.95.

In this work, we report the successful synthesis of a new intermetallic compound Dy2Ni0.87Si2.95 forming in single phase only with a chemically disordered structure. The random distribution of Ni/Si and crystal defects create a variation in the local electronic environment between the magnetic Dy ions. In the presence of both disorder and competing exchange interactions driven magnetic frustration, originating due to c/a ∼ 1, the compound undergoes spin freezing behaviour below 5.6 K. In the non-equilibrium state below the spin freezing behaviour, the compound exhibits aging phenomena and magnetic memory effects. In the magnetically short-range ordered region, much above the freezing temperature, an unusual occurrence of considerable magnetic entropy change, -ΔSmaxM ∼ 21 J kg-1 K-1 with large cooling power RCP ∼ 531 J kg-1 and adiabatic temperature change, ΔTad ∼ 10 K for a field change of 70 kOe, is observed for this short range ordered cluster-glass compound without any magnetic hysteresis loss.

Role of random magnetic anisotropy on the valence, magnetocaloric and resistivity properties in a hexagonal Sm2Ni0.87Si2.87 compound.

In this work, we report the effect of random magnetic anisotropy (RMA) on the valence, magnetocaloric and resistivity properties in a glassy intermetallic material Sm2Ni0.87Si2.87. On the basis of detailed studies on the valence band and core level electronic structure, we have established that both the Sm3+ and Sm2+ ions are present in the system, suggesting the compound to be of mixed valence in nature. The significant observation of positive magnetic entropy change in zero-field cooled measurement has been argued due to the presence of RMA that develops due to local electronic environmental variations between the rare-earth ions in the system. The quantum interference effect caused by the elastic electron-electron interaction is responsible for the resistivity upturn at low-temperature for this disordered metallic conductor.

Chemical disorder driven reentrant spin cluster glass state formation and associated magnetocaloric properties of Nd2Ni0.94Si2.94.

In this work, we report the synthesis of a new ternary intermetallic compound, Nd2Ni0.94Si2.94, that forms in single phase only in a defect crystal structure. The compound exhibits an antiferromagnetic transition below 7.2 K (TN) followed by a spin cluster freezing behaviour below 2.85 K (Tf), which makes the compound a reentrant spin cluster glass system. The detailed studies of dc and ac magnetization, heat capacity, non-equilibrium dynamical behaviour, viz., aging effect, temperature and field dependent magnetic relaxation and magnetic memory effect establish the compound to be a cluster-glass material below freezing temperature. The interplay between competing exchange coupling (c/a ≃ 1.04 ⇒ JNN ≃ JNNN) and chemical disorder driven variation in the electronic environment among the Nd ions has been argued to be responsible for such a metastable state formation. A considerable value of MCE parameters (-ΔS ∼ 11.4 J kg-1 K-1, RCP ∼ 160 J kg-1 and ΔTad ∼ 5.2 K for a field change of 70 kOe) is obtained for this magnetically frustrated glassy compound.

Low-field induced large magnetocaloric effect in Tm2Ni0.93Si2.93: influence of short-range magnetic correlation.

In this work, we report the successful synthesis of a new intermetallic compound Tm2 [Formula: see text] [Formula: see text] that forms in single phase only in defect crystal structure. The compound does not show any long range magnetic ordering down to 2 K. The material exhibits a large magnetic entropy change ([Formula: see text] J [Formula: see text] K-1) and adiabatic temperature change ([Formula: see text] K) at 2.2 K for a field change of 20 kOe which can be realized by permanent magnets, thus being very beneficial for application purpose. In the absence of long-range magnetic ordering down to 2 K, the metastable nature of low-temperature spin dynamics and short-range magnetic correlations are considered to be responsible for such a large magnetocaloric effect over a wide temperature region.

Magnetic frustration induced large magnetocaloric effect in the absence of long range magnetic order.

We have synthesized a new intermetallic compound Ho2Ni0.95Si2.95 in a single phase with a defect crystal structure. The magnetic ground state of this material found to be highly frustrated without any long range order or glassy feature as investigated through magnetic, heat capacity and neutron diffraction measurements. The interest in this material stems from the fact that despite the absence of true long range order, large magnetocaloric effect (isothermal magnetic entropy change, -ΔSM ~ 28.65 J/Kg K (~205.78 mJ/cm3 K), relative cooling power, RCP ~ 696 J/Kg (~5 J/cm3) and adiabatic temperature change, ΔT ad ~ 9.32 K for a field change of 70 kOe) has been observed which is rather hard to find in nature.

Multiple crossovers between positive and negative magnetoresistance versus field due to fragile spin structure in metallic GdPd3.

Studies on the phenomenon of magnetoresistance (MR) have produced intriguing and application-oriented outcomes for decades-colossal MR, giant MR and recently discovered extremely large MR of millions of percents in semimetals can be taken as examples. We report here the discovery of novel multiple sign changes versus applied magnetic field of the MR in the cubic intermetallic compound GdPd3. Our study shows that a very strong correlation between magnetic, electrical and magnetotransport properties is present in this compound. The magnetic structure in GdPd3 is highly fragile since applied magnetic fields of moderate strength significantly alter the spin arrangement within the system-a behavior that manifests itself in the oscillating MR. Intriguing magnetotransport characteristics of GdPd3 are appealing for field-sensitive device applications, especially if the MR oscillation could materialize at higher temperature by manipulating the magnetic interaction through perturbations caused by chemical substitutions.

Comparison of Carotid Intima Media Thickness in Children of Patients with and without Premature Coronary Artery Disease.

INTRODUCTION: Increased Carotid Intima Medial Thickness (CIMT) is associated with cardiovascular risk factors and vascular events like Coronary Artery Disease (CAD) and stroke. AIM: This study was designed to identify whether CIMT is increased in the children of parents with premature coronary artery disease and compare it with age and sex matched controls who are children of normal individuals. We also tried to compare and correlate the changes in CIMT if any, among the study group with relation to family history of diabetes and hypertension. MATERIALS AND METHODS: It was an observational prospective case control study. Twenty five cases (children of parents with premature coronary artery disease) were recruited as per the inclusion and exclusion criteria. Age and sex matched controls were recruited from the paediatric Outpatient Department (OPD). The CIMT was measured using ultrasound Doppler as per the protocol by the Mannheim intima media thickness consensus statement. RESULTS: Ten children out of 25 controls had CIMT of 0.05 cm and 5 out of 25 cases had CIMT of 0.07 cm. The association between cases and controls was not statistically significant. Even though the CIMT increases after 10 years, there is no statistically significant association between cases and controls in the different age groups. Out of the total 48% of the children among the case group had family history of hypertension whereas 28% in the control group. A 33% of children in the case group with family history of hypertension had CIMT of 0.07 cm; 46% of children in case group without family history of hypertension had CIMT of 0.05 cm. This difference was statistically significant (p=0.005). There was no significant association between family history of diabetes mellitus and CIMT in both groups. CONCLUSION: There was significant association between CIMT in children with family history of premature CAD and family history of hypertension when compared with no family history of hypertension with premature CAD. There was no significant association between CIMT of children with and without family history of premature CAD.

Griffiths phase behaviour in a frustrated antiferromagnetic intermetallic compound.

The rare coexistence of a Griffiths phase (GP) and a geometrically frustrated antiferromagnetism in the non-stoichiometric intermetallic compound GdFe0.17Sn2 (the paramagnetic Weiss temperature θp ~ -59 K) is reported in this work. The compound forms in the Cmcm space group with large structural anisotropy (b/c ~ 4). Interestingly, all the atoms in the unit cell possess the same point group symmetry (Wycoff position 4c), which is rather rare. The frustration parameter, f = |θp|/TN has been established as 3.6, with the Néel temperature TN and Griffiths temperature TG being 16.5 and 32 K, respectively. The TG has been determined from the heat capacity measurement and also from the magnetocaloric effect (MCE). It is also shown that substantial difference in GP region may exist between zero field and field cooled measurements - a fact hitherto not emphasized so far.

Atrial fibrillation and stroke prevention: is warfarin still an option?--No.

Atrial fibrillation is a common arrhythmia that increases the risk of stroke by 4.5 times. Anticoagulant/antithrombotic therapy in atrial fibrillation has been inconsistent and inappropriate. Warfarin enjoyed the monopoly of being the primary medication used to reduce the risk of thromboembolic events. Warfarin has many limitations in its use as an ideal anticoagulant. To overcome this difficulty, now there are two main alternative groups to warfarin namely, direct thrombin inhibitors (ximelagatran and dabigatran) and factor Xa inhibitors (apixaban, rivaroxaban, edoxaban, etc.). The advantages of the newer anticoagulants over the conventional warfarin are numerous. There are three landmark trials which have shown some light to the path of newer anticoagulant era, which include the following: RE-LY, ROCKET AF and ARISTOTLE. Head to head comparison of warfarin with newer anticoagulants showed the superiority of newer anticoagulants over warfarin in terms of efficacy and favorable side effect profile. After few decades of using warfarin, it's high time to enter into the era of newer anticoagulants and bid adieu to warfarin.

The relevance of "Nonsmoking-associated lung cancer" in India: a single-centre experience.

BACKGROUND: Lung cancer remains a major cause of morbidity and mortality worldwide, accounting for more deaths than any other cancer cause. AIM: The aim of this study was to analyze the clinical profile and the epidemiological trends in lung cancer patients from a single centre with an emphasis on the smoking practices. MATERIALS AND METHODS: This is a retrospective analysis of prospectively collected data of 258 consecutive hospital in-patients with a proven diagnosis of lung cancer at a tertiary care oncology centre between 2003 and 2007. RESULTS: The median age of patients in our study was 56 years; the male to female ratio was approximately 3.5:1. Non-small-cell lung cancer (NSCLC) was the predominant histology in 224 patients; the histology in the remaining 34 patients was small-cell carcinoma. Within NSCLC, the most common histology was adenocarcinoma followed by squamous cell carcinoma. One hundred and two patients were never-smokers as compared to 156 patients who were ever-smokers. Among the smokers, the majority of them were found to be cigarette smokers compared to 28.2% bidi smokers. There was a very significant correlation found with adenocarcinoma among nonsmokers, and with squamous cell carcinoma among the smokers compared to non-smokers. CONCLUSIONS: Our study suggests that the epidemiology of lung cancer in India is possibly changing, with close to 40% of our lung cancer patients being nonsmokers. More importantly, our study reflects the global trend of rise in adenocarcinoma histology. These observations need to be substantiated in similar studies of larger magnitude, preferably population-based.

Large variations in the magnetic ordering behavior of EuCu(2)As(2) with the application of external pressure and magnetic field.

The influence of external pressure on the electrical transport and magnetic properties of EuCu(2)As(2), crystallizing in a ThCr(2)Si(2)-type structure, is reported. The system is known to be an antiferromagnet below T(N) ≈ 15 K in the absence of external magnetic fields. We find that there is a gradual reduction of T(N) with the application of a magnetic field with an extrapolated value of the critical field of around 18 kOe which can drive T(N) to zero. Electrical resistivity under pressure (<11 GPa) reveals that the magnetic ordering temperature is pushed up dramatically to higher temperatures which is quite interesting if compared with the behavior in isostructural FeAs-based systems containing Eu. Above 7 GPa, the pressure-induced state appears to be ferromagnetic. The results thus reveal interesting changes in the magnetic ordering behavior of this compound with increasing pressure and magnetic fields.

Prolonged treatment with vitamin D in postmenopausal women with primary hyperparathyroidism.

INTRODUCTION/BACKGROUND: Vitamin D deficiency further increases circulating parathyroid hormone (PTH) levels in patients with primary hyperparathyroidism (pHPT), with potential detrimental effects on bone mass. METHODS: This was an observational clinical study in consecutive conservatively treated postmenopausal women (n=40) with pHPT and coexistent 25-hydroxyvitamin D deficiency (25OHD ≤50 nmol/l (≤20 ng/ml)). Patients who showed an increase in serum 25OHD above the threshold of vitamin D deficiency (>50 nmol/l; n=28) using treatment with various commonly prescribed vitamin D preparations were, for the purposes of statistical analyses, allocated to the treatment group. Patients who were retrospectively identified as having received no treatment with vitamin D and/or remained vitamin D deficient were considered as non-responders/controls (n=12). Adjusted calcium (adjCa), PTH and 25OHD concentrations were monitored in all subjects up to 54 months (mean observation period of 18±2 months). RESULTS: Prolonged increased vitamin D intake, regardless of the source (serum 25OHD, increase from 32.2±1.7 nmol/l at baseline to 136.4±11.6 nmol/l, P<0.0001), significantly reduced serum PTH (13.3±1.1 vs 10.5±1.0 pmol/l, P=0.0001), with no adverse effects on adjCa levels (2.60±0.03 vs 2.60±0.02 mmol/l, P=0.77) and renal function tests (P>0.73). In contrast, serum PTH remained unchanged (15.8±2.6 vs 16.3±1.9 pmol/l, P=0.64) in patients who remained vitamin D deficient, with a significant difference between groups in changes of PTH (P=0.0003). Intrapartial correlation analyses showed an independent negative correlation of changes in 25OHD with PTH levels (r ic=-0.41, P=0.014). CONCLUSIONS: Prolonged treatment with vitamin D in various commonly prescribed preparations appeared to be safe and significantly reduced PTH levels by 21%.