Correlating the Dipolar Interactions Induced Magneto-Viscoelasticity and Thermal Conductivity Enhancements in Nanomagnetic Fluids.

The effective thermal management of electronic system holds the key to maximize their performance. The recent miniaturization trends require a cooling system with high heat flux capacity, localized cooling, and active control. Nanomagnetic fluids (NMFs) based cooling systems have the ability to meet the current demand of the cooling system for the miniaturized electronic system. However, the thermal characteristics of NMFs have a long way to go before the internal mechanisms are well understood. This review mainly focuses on the three aspects to establish a correlation between the thermal and rheological properties of the NMFs. First, the background, stability, and factors affecting the properties of the NMFs are discussed. Second, the ferrohydrodynamic equations are introduced for the NMFs to explain the rheological behavior and relaxation mechanism. Finally, different theoretical and experimental models are summarized that explain the thermal characteristics of the NMFs. Thermal characteristics of the NMFs are significantly affected by the morphology and composition of the magnetic nanoparticles (MNPs) in NMFs as well as the type of carrier liquids and surface functionalization that also influences the rheological properties. Thus, understanding the correlation between the thermal characteristics of the NMFs and rheological properties helps develop cooling systems with improved performance.

Idiopathic Membranous Glomerulonephritis Leading to Secondary Polycythemia: A Rare Association.

Primary polycythemia is caused due to mutations in erythropoietin (EPO) receptor or Janus Kinase 2 (JAK2). Secondary polycythemia is seldom associated with renal diseases, such as adult polycystic kidney disease, kidney tumors (like renal cell carcinoma and reninoma), renal artery stenosis, and kidney transplant due to increased EPO production. Polycythemia associated with nephrotic syndrome (NS) is very rare. Here, we report a case with membranous nephropathy, the patient had polycythemia at presentation. Nephrotic range proteinuria causes nephrosarca leading to renal hypoxia which causes increased EPO and IL-8 production, this is proposed to cause secondary polycythemia in NS. The reduction of polycythemia following remission in proteinuria further suggests the correlation. The exact mechanism remains to be found out.

Facile synthesized zinc oxide nanorod film humidity sensor based on variation in optical transmissivity.

Variation in the transmitted light intensity from metal oxide thin films with moisture content provides a great opportunity to use them for humidity sensing. Herein, we have developed a novel and simple humidity sensor based on ZnO nanorod (ZNR) thin films which work as transmission-based sensing elements in an in-house fabricated sensing setup. The ZNR sensing element shows excellent linear sensing performance in the relative humidity (RH) range 10-90% and does not show any hysteresis. A maximum change in optical power of ∼95 µW is observed with the change in RH in the range 10-90%, for the sample with the smallest crystallite size (ZNR1) and highest pore diameter of the ZNR film. Also, a maximum sensitivity of 1.104 µW/% RH is observed for the ZNR1 sample which drops to 0.604 µW/% RH for the highest crystallite size sample (ZNR4). The presence of oxygen vacancies and the micro-porous nature of the film allow the absorption of water vapour on the film which deflects light at different angles that vary with the moisture content. The experimental results suggest that the ZNR film with a smaller crystallite size and larger pore diameter is more sensitive for humidity measurements. Further, an improved sensing performance is perceived in ZNRs because of the larger surface area of the nanorods. The ZNR based sensing elements do not suffer from ageing effects and exhibit high repeatability (88.74%). Further, the humidity sensor has a response time of 62 seconds and recovery time of 100 seconds which can be considered as a fairly quick response.

A case of "very" very late stent thrombosis: More than 12 years after DES.

A rare but possibly catastrophic consequence of drug-eluting stents (DES) is very late stent thrombosis. We report a case of 74-year-old male who sustained a ST elevation myocardial infarction (STEMI) 12 years after initial Paclitaxel eluting stent implantation (PES). This is the longest time between stent placement and the development of an acute coronary event due to very late stent thrombosis that we are aware of (VLST). The implications for prognosis and therapy are significant because they highlight the uncertainty around the recommended duration of antiplatelet medication in patients with DES. Clinicians face challenges in treating those patients particularly when competing medical conditions demand the discontinuation of antiplatelet therapy. VLST is concerning since the underlying pathophysiology is unknown, and the best preventive treatments and duration of antiplatelet medication after stent implantation are unknown.

An assessment of various potentially toxic elements and associated health risks in agricultural soil along the middle Gangetic basin, India.

The present study analysed the levels of potentially toxic elements along with physico-chemical properties of agricultural soil samples (n = 59) collected from fields situated along the path of river Ganga in the middle Gangetic floodplain in two districts, Ballia and Ghazipur. Arsenic (As), chromium (Cr), copper (Cu), nickel (Ni), zinc (Zn), lead (Pb), iron (Fe) and manganese (Mn) levels were analysed by Wavelength Dispersive-X-Ray Fluorescence Spectroscopy (WD-XRF) and the associated health risks along with diverse indices were calculated. The mean concentrations of As, Cu, Cr, Pb, Zn and Ni were found to be 15, 42, 85, 18, 87 and 47 mg kg-1, respectively in Ballia and 13, 31, 73, 22, 77 and 34 mg kg-1, respectively in Ghazipur. Physico-chemical properties like pH, ORP and organic matter were found to be 7.91, 209 and 1.20, respectively in Ballia and 8.51, 155 and 1.25, respectively in Ghazipur. The calculated health quotient (HQ) for all the elements was observed to be within the threshold value of one, however with few exemptions. Therefore, the present study showcases the contamination of potentially toxic elements in agricultural fields and possible health hazards for people.

Thrombotic Thrombocytopenic Purpura: A Tale of Two Cases.

Microangiopathic hemolytic anaemia, thrombocytopenia, renal failure, neurologic abnormalities, and fever form the pentad of thrombotic thrombocytopenic purpura (TTP). Early diagnosis is crucial because TTP responds well to plasmapheresis therapy but is associated with substantial mortality if left untreated. A substantial percentage of patients with TTP used to die from systemic microvascular thrombosis in the brain and the heart. However, since plasma exchange therapy became a mainstay in the treatment of TTP, mortality has reduced considerably. Diagnosing TTP can be difficult due to the vast range of symptoms and the absence of clearly defined diagnostic criteria. Hemolytic uremic syndrome and disseminated intravascular coagulation are a close differential of TTP. Here we report two patients with TTP who achieved remission when treated with steroids, plasmapheresis and were free of disease relapse till about two months during follow-up in the outpatient department.

Facile Synthesis, Static, and Dynamic Magnetic Characteristics of Varying Size Double-Surfactant-Coated Mesoscopic Magnetic Nanoparticles Dispersed Stable Aqueous Magnetic Fluids.

The present work reports the synthesis of a stable aqueous magnetic fluid (AMF) by dispersing double-surfactant-coated Fe3O4 magnetic nanoparticles (MNPs) in water using a facile ambient scalable wet chemical route. MNPs do not disperse well in water, resulting in low stability. This was improved by dispersing double-surfactant (oleic acid and sodium oleate)-coated MNPs in water, where cross-linking between the surfactants improves the stability of the AMFs. The stability was probed by rheological measurements and all the AMF samples showed a good long-term stability and stability against a gradient magnetic field. Further, the microwave spin resonance behavior of AMFs was studied in detail by corroborating the experimental results obtained from the ferromagnetic resonance (FMR) technique to theoretical predictions by appropriate fittings. A broad spectrum was perceived for AMFs which indicates strong ferromagnetic characteristics. The resonance field shifted to higher magnetic field values with the decrease in particle size as larger-size MNPs magnetize and demagnetize more easily since their magnetic spins can align in the field direction more definitely. The FMR spectra was fitted to obtain various spin resonance parameters. The asymmetric shapes of the FMR spectra were observed with a decrease in particle sizes, which indicates an increase in relaxation time. The relaxation time increased with a decrease in particle sizes (sample A to D) from 37.2779 ps to 42.8301 ps. Further, a detailed investigation of the structural, morphological, and dc magnetic properties of the AMF samples was performed. Room temperature dc magnetic measurements confirmed the superparamagnetic (SPM) characteristics of the AMF and the M-H plot for each sample was fitted with a Langevin function to obtain the domain magnetization, permeability, and hydrodynamic diameter of the MNPs. The saturation magnetization and coercivity of the AMF samples increased with the increase in dispersed MNPs' size of the samples. The improvement in the stability and magnetic characteristics makes AMFs suitable candidates for various biomedical applications such as drug delivery, magnetic fluid hyperthermia, and biomedicines.

Interface chemistry of two-dimensional heterostructures - fundamentals to applications.

Two-dimensional heterostructures (2D HSs) have emerged as a new class of materials where dissimilar 2D materials are combined to synergise their advantages and alleviate shortcomings. Such a combination of dissimilar components into 2D HSs offers fascinating properties and intriguing functionalities attributed to the newly formed heterointerface of constituent components. Understanding the nature of the surface and the complex heterointerface of HSs at the atomic level is crucial for realising the desired properties, designing innovative 2D HSs, and ultimately unlocking their full potential for practical applications. Therefore, this review provides the recent progress in the field of 2D HSs with a focus on the discussion of the fundamentals and the chemistry of heterointerfaces based on van der Waals (vdW) and covalent interactions. It also explains the challenges associated with the scalable synthesis and introduces possible methodologies to produce large quantities with good control over the heterointerface. Subsequently, it highlights the specialised characterisation techniques to reveal the heterointerface formation, chemistry and nature. Afterwards, we give an overview of the role of 2D HSs in various emerging applications, particularly in high-power batteries, bifunctional catalysts, electronics, and sensors. In the end, we present conclusions with the possible solutions to the associated challenges with the heterointerfaces and potential opportunities that can be adopted for innovative applications.

Spin dynamics investigations of multifunctional ambient scalable Fe3O4 surface decorated ZnO magnetic nanocomposite using FMR.

Microwave spin resonance behavior of the Fe3O4 surface decorated ZnO nanocomposites (FZNC) has been investigated by ferromagnetic resonance (FMR). Modified hydrothermal method has been adopted to fabricate FZNC samples with Fe3O4 nanoparticles chains were used as seeds in the uniform magnetic field to decorate them on the surface of the ZnO nanoparticles in a unique configuration. Spin dynamics investigation confirms the transition of ZnO from diamagnetic to ferromagnetic as the sharp FMR spectra converts to the broad spectra with Fe3O4 nanoparticles incorporation. A single broad FMR spectra confirms that no isolated Fe3+ or Zn2+ ions exist which is also in agreement with XRD confirming suitable composite formation. Further, the increase in Fe3O4 concentration leads to decrease in g-value which is resulting from the internal field enhancement due to magnetic ordering. Also, various spin resonance parameters were calculated for the FZNC which provides a detail information about the magnetic ordering, exchange coupling and anisotropy. Elemental analysis confirms the presence of Fe and Zn simultaneously and transmission electron microscopy (TEM) image show the presence of Fe3O4 on the grain boundaries of ZnO which has been confirmed by taking high-resolution TEM and electron diffraction patterns on both sides of the interface. These unique structural configuration of the FZNC has tremendous potential in various magneto-optoelectronic, spintronics and electro-chemical applications.

Temperature selectivity for single phase hydrothermal synthesis of PEG-400 coated magnetite nanoparticles.

Herein, we have presented a detailed investigation of the temperature effect on hydrothermal synthesis of Fe3O4 magnetic nanoparticles (MNPs). The appearance of single-phase cubic spinel Fe3O4 at and above critical temperature provides a clear indication that temperature plays a crucial role in the single-phase synthesis of the Fe3O4 MNPs. A detailed investigation of the structural, magnetic and spin dynamic properties of PEG-400 coated Fe3O4 MNPs synthesized by a facile hydrothermal method at different temperatures (120 °C, 140 °C, 160 °C and 180 °C for 16 hours) has been presented. The single-phase cubic magnetite structure with high crystallinity was found in the samples synthesized at 160 and 180 °C and confirmed from XRD results, whereas samples prepared at 120 and 140 °C are of mixed phase (α-Fe2O3 and Fe3O4). The magnetic hysteresis curves reveal that saturation magnetization and coercivity of MNPs enhanced systematically with the increase in the reaction temperature from 120 °C to 180 °C. Maximum saturation magnetization (88.98 emu g-1) and coercivity (134.16 Oe) were found for the sample synthesized at 180 °C. Furthermore, ferromagnetic resonance (FMR) spectra obtained for samples synthesised at higher temperatures indicate a lower value of the line width due to the high magnetic ordering in the samples. Also, the resonance field decreased, and the g-value increased due to enhancement in magnetization for the single-phase samples synthesized at higher reaction temperatures. The spin resonance properties obtained from fitting the FMR data clearly indicate that a large spin-orbit coupling was observed for the single phase Fe3O4 MNPs and excellent magnetic properties were obtained from the static magnetic measurements.

Microwave spin resonance investigation on the effect of the post-processing annealing of CoFe2O4 nanoparticles.

A novel investigation on the finite-size effects on the spin resonance properties of cobalt ferrite (CoFe2O4) nanoparticles has been performed using a room temperature ferromagnetic resonance (FMR) technique. A single broad spectrum was obtained for the CoFe2O4 nanoparticle samples, which indicated that all the samples were showing ferromagnetic characteristics. An asymmetric FMR line shape with a hefty trailing section was obtained due to the high magneto-crystalline anisotropy in CoFe2O4 nanoparticles, which changed with the size distribution. The resonance field for the samples shifted to a higher value due to the increase in the magneto-crystalline anisotropy in the CoFe2O4 nanoparticles with an increase in size. A systematic change in the resonance field and line width was observed with the change in the size distribution of the particles. Initially, it decreased with an increase in the size of the particles and increased after the critical size range. The critical size range is the imprint of the shift of the magnetic domain from a single domain to multi domain. The line width increased at higher annealing temperatures due to the enhancement in the dipole-dipole interaction, which led to a higher spin concentration as well as magneto-crystalline anisotropy. Furthermore, the saturation magnetization (M s) as well as 'M r/M s' increased from 37.7 to 71.4 emu g-1 and 0.06 to 0.31, respectively. The highest coercivity (750.9 Oe) and anisotropy constant (4.62 × 104 erg cm-3) were found for the sample annealed at 700 °C, which can be corroborated by the literature as the critical annealing temperature at which CoFe2O4 nanoparticles shift from single domain nanoparticles to multi-domain nanoparticles. Post-processing annealing is critical in advanced processing techniques and spin dynamics plays a vital role in various interdisciplinary areas of applications.

Warfarin: A double-edged sword.

Warfarin is the commonest anticoagulant used in today's practice; it has a very narrow therapeutics window. Under and overdosing results in various life-threatening complications. Warfarin-related nephropathy (WRN) is a rare cause of acute kidney injury (AKI) in patients on long-term anticoagulation, as a result of supratherapeutic anticoagulation. Warfarin causes AKI by inducing glomerular hemorrhage with subsequent tubular obstruction by red blood cell (RBC) casts. WRN has been associated with irreversible kidney injury and increased risk of mortality. Despite a better understanding of pathophysiology and histopathology of WRN, its preventive measures and clinical outcome are not well known. We report here the case of a 62-year-old male, who was on a long-term warfarin therapy due to chronic atrial fibrillation with a history of old ischemic stroke and dilated cardiomyopathy. He was presented with AKI and his renal biopsy was suggestive of WRN. He was managed by withholding warfarin for a few days until the therapeutic range of international normalized ratio was achieved and steroids and N-acetylcysteine (NAC) recovered. WRN is a diagnosis of exclusion; other causes of AKI must be ruled out. Renal biopsy is the gold standard for diagnosis. Patients on chronic anticoagulant therapy should be monitored periodically for the therapeutic range of anticoagulants, deterioration of renal function, and hematuria.

Clinicolaboratory profile of expanded dengue syndrome - Our experience in a teaching hospital.

INTRODUCTION: Classic dengue fever presentation has expanded its horizon by involving various organ systems and is named as expanded dengue syndrome. This changing presentation and rising burden across the globe may lead to delayed diagnosis and under reporting of this syndrome. AIM OF STUDY: To analyze clinicolaboratory profile of patients with expanded dengue syndrome. MATERIALS AND METHODS: About 520 cases of expanded dengue syndrome as per World Health Organization definition criteria 2012 were studied with their informed consent. Detailed history, thorough clinical examination, and relevant investigations were done. Their clinical and laboratory parameters were analyzed. Standard treatment guidelines were followed in all cases. OBSERVATION: About 301 patients were male and 219 were female with male-to-female ratio of 3:2. Their age varied from 12 to 76 years with the average age of 47.5 years. About 92% of cases presented with various gastro hepatic manifestations. The commonest gastrohepatic manifestation was transaminitis (57.5%) that is asymptomatic elevation of liver enzymes followed by acalculous cholecystitis (21%) and acute pancreatitis (13.9%). Twenty-nine patients presented with various neurological manifestations. Three patients presented with acute kidney injury and eight patients had coinfection with malaria. Fever with nausea and vomiting was the most common presentation. About 15% of patients presented with bleeding manifestations. About 40.6% of patients presenting as abdominal manifestations had platelet count <20,000/mm3 and needed platelet transfusion versus 9.8% with other system involvement (central nervous system, cardiovascular system (CVS), renal). Hepatomegaly was the most common ultrasonography (USG) finding being present in 57.5% of patients followed by acalculous cholecystitis in 21.3%. Total mortality was 1.9% in our series. We lost eight patients presenting with neurological manifestations and two patients with coinfection with malaria. CONCLUSION: Atypical presentations should prompt us to investigate for dengue especially during ongoing epidemics so that expanded dengue syndrome can be diagnosed and treated early.

Dipolar Interaction and Magneto-Viscoelasticity in Nanomagnetic Fluid.

We investigate the effect of dilution on dipolar interaction with linear and non-linear rheological properties of kerosene based magnetic fluid. The steady-state behavior demonstrate a shear thinning behavior and corroborated with a power law, (η = c γ ˙ n + η∞) exponent, n ≤ 1. The shear-induced-breakup (separation) of nanoparticles and the yielding behavior has been explained by Bingham model. Moreover, the magnetoviscous effect showed an initial increase at low shear rate and decrease at higher shear rate. Further, specific viscosity (ηF)-versus-Mason number (Mn) shows a perfect scaling at lower Mn (≤10-4) confirming negligible thermal and colloidal forces. Whereas, at higher Mn (≥10-3) deviation from collapse indicates the dominance of Brownian forces acting on nanofluids. The magnetic field dependent elastic (G') and viscous (G″) modulus reveal a crossover from viscoelastic-to-viscous behavior of nanofluid at critical concentration. Finally, we compare viscoelastic results with De Gans diagonal scaling theory to correlate the functional dependence of storage and loss modules with different particle volume concentration.

Treatment of orange II azo-dye by electrocoagulation (EC) technique in a continuous flow cell using sacrificial iron electrodes.

This paper describes the EC treatment of orange II dye solution in a flow cell using sodium chloride as an internal electrolyte. In this technique dye solutions were passed through a flow-through EC apparatus consisting of a flow-through cell, the electrode assembly, the feed pump and the DC power supply unit. The cell contained five parallel iron electrodes, which form four parallel cells. Experiments were run at 25 degrees C under various electrolyte concentrations, dye concentrations, current density, flow rate of the solution, and pH at dc current range of 2-5A. Various number of recycles of the treated dye solution were also performed at the same dc current range. Optimum conditions to get high removal efficiency were experimentally determined. It was found that 98.5% of the dye was removed from the solution under the optimum conditions. The residue from a blank run (pH = 7.3) and a dye added run (pH = 8.5) were collected by vacuum filtration and analyzed by XRD after drying in a vacuum desiccator. The XRD data indicated the presence of mainly maghemite (gamma-Fe2O3) and magnetite (Fe3O4) in the residue. However, there is not much difference between the X-ray diffractograms of the blank sample and the dye-containing residue to warrant any conclusions therefrom with regard to the interactions between the oxides and the dye molecules.