Publications by authors named "Jeevan H"

Root-knot nematodes (Meloidogyne spp.) are significant pests that cause considerable damage to crops, prompting a need for sustainable control methods. This study evaluated the nematicidal potential of fungal culture filtrates and botanicals as eco-friendly alternatives.

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Article Synopsis
  • This research investigates the chemical treatment of novel ligno-cellulose fibers extracted from the bark of the Careya arborea plant, which is native to the Indian subcontinent and Afghanistan.
  • The fibers contain a significant amount of cellulose (71.17 wt%) and hemicellulose (27.86 wt%) and exhibit low density (1140 kg/m), making them ideal for lightweight applications across various industries.
  • Chemical treatments using NaOH at different concentrations successfully altered the fibers' structure, enhancing their thermal stability and mechanical properties, thereby offering promising solutions for high-temperature and sustainable applications.
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The utilization of CRISPR/Cas9 in Spodoptera frugiperda, commonly known as fall armyworm, presents a groundbreaking avenue for pest management. With its ability to precisely modify the insect's genome, CRISPR/Cas9 offers innovative strategies to combat this destructive pest. The application of CRISPR/Cas9 in S.

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Nuclear magnetic resonance measurements were performed on CeCu_{2}Si_{2} in the presence of a magnetic field close to the upper critical field μ_{0}H_{c2} in order to investigate its superconducting (SC) properties near pair-breaking fields. In lower fields, the Knight shift and nuclear spin-lattice relaxation rate divided by temperature 1/T_{1}T abruptly decreased below the SC transition temperature T_{c}(H), a phenomenon understood within the framework of conventional spin-singlet superconductivity. In contrast, 1/T_{1}T was enhanced just below T_{c}(H) and exhibited a broad maximum when magnetic fields close to μ_{0}H_{c2}(0) were applied parallel or perpendicular to the c axis; although the Knight shift decreased just below T_{c}(H).

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The nature of the pairing symmetry of the first heavy fermion superconductor CeCuSi has recently become the subject of controversy. While CeCuSi was generally believed to be a d-wave superconductor, recent low-temperature specific heat measurements showed evidence for fully gapped superconductivity, contrary to the nodal behavior inferred from earlier results. Here, we report London penetration depth measurements, which also reveal fully gapped behavior at very low temperatures.

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In exotic superconductors, including high- copper oxides, the interactions mediating electron Cooper pairing are widely considered to have a magnetic rather than a conventional electron-phonon origin. Interest in this exotic pairing was initiated by the 1979 discovery of heavy-fermion superconductivity in CeCuSi, which exhibits strong antiferromagnetic fluctuations. A hallmark of unconventional pairing by anisotropic repulsive interactions is that the superconducting energy gap changes sign as a function of the electron momentum, often leading to nodes where the gap goes to zero.

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Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, because the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity, and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with (3)He gas are widely used for cooling below 1 K. However, usage of the gas has been increasingly difficult because of the current worldwide shortage.

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Our comprehensive study on EuFe_{2}As_{2} reveals a dramatic reduction of magnetic detwinning fields compared to other AFe_{2}As_{2} (A=Ba, Sr, Ca) iron pnictides by indirect magnetoelastic coupling of the Eu^{2+} ions. We find that only ∼0.1  T are sufficient for persistent detwinning below the local Eu^{2+} ordering; above T_{Eu}=19  K, higher fields are necessary.

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By systematic investigations of the magnetic, transport, and thermodynamic properties of single crystals of EuFe(2)(As(1-x)P(x))(2) (0≤x≤1), we explore the complex interplay of superconductivity and Eu(2+) magnetism. Below 30 K, two magnetic transitions are observed for all P substituted crystals, suggesting a revision of the phase diagram. In addition to the canted A-type antiferromagnetic order of Eu(2+) at ∼20  K, a spin glass transition is discovered at lower temperatures.

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We study the in-plane anisotropy of the thermoelectric power and electrical resistivity on detwinned single crystals of isovalent substituted EuFe(2)(As(1-x)P(x))(2). Compared to the resistivity anisotropy, the thermopower anisotropy is more pronounced and clearly visible already at temperatures much above the structural and magnetic phase transitions. Most remarkably, the thermopower anisotropy changes sign below the structural transition.

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We employed femtosecond time- and angle-resolved photoelectron spectroscopy to analyze the response of the electronic structure of the 122 Fe-pnictide parent compounds Ba/EuFe(2)As(2) and optimally doped BaFe(1.85)Co(0.15)As(2) near the Γ point to optical excitation by an infrared femtosecond laser pulse.

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We investigated the optical reflectivity of the heavy-fermion metal CeCu(2)Si(2) in the energy range 3 meV-30 eV for temperatures between 4 and 300 K. The results for the charge dynamics indicate a behavior that is expected for the formation of a coherent heavy quasiparticle state: upon cooling the spectra of the optical conductivity indicate a narrowing of the coherent response. Below temperatures of 30 K a considerable suppression of conductivity evolves below a peak structure at 13 meV.

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Regardless of the improvements in the design of prosthetic heart valves and the use of anticoagulation, systemic embolism and valve thrombosis remains the most dreaded complications of mechanical heart valve replacement. A course of thrombolytic therapy may be considered as a first-line therapy for prosthetic heart valve thrombosis. The safety of thrombolysis in early pregnancy is not known.

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Employing the momentum sensitivity of time- and angle-resolved photoemission spectroscopy we demonstrate the analysis of ultrafast single- and many-particle dynamics in antiferromagnetic EuFe(2)As(2). Their separation is based on a temperature-dependent difference of photoexcited hole and electron relaxation times probing the single-particle band and the spin density wave gap, respectively. Reformation of the magnetic order occurs at 800 fs, which is 4 times slower compared to electron-phonon equilibration due to a smaller spin-dependent relaxation phase space.

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We carried out specific-heat and ac-susceptibility experiments under hydrostatic pressure to investigate the interplay of spin-density-wave antiferromagnetism (A) and superconductivity (S) in single-crystalline AS-type CeCu(2)Si(2). We find evidence for a line of magnetic-field- and pressure-tuned quantum critical points in the normal state in the zero-temperature magnetic field-pressure plane. Our analysis suggests an extension of this line into the superconducting state and corroborates the close connection of the underlying mechanisms leading to the formation of the antiferromagnetic and the superconducting states in AS-type CeCu(2)Si(2).

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We report on the magnetic excitation spectrum in the normal state of the heavy-fermion superconductor CeCu92)Si(2) on approaching the quantum critical point (QCP). The magnetic response in the superconducting state is characterized by a transfer of spectral weight to energies above a spin excitation gap. In the normal state, a slowing-down of the quasielastic magnetic response is observed, which conforms to the scaling expected for a QCP of spin-density-wave type.

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The tetragonal heavy-fermion compound CeCu₂Si₂ exhibits a superconducting ground state (S type, T(c) = 0.67 K) close to a magnetic instability. Here, we present angle-resolved resistivity measurements of the upper critical field H(c2).

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We have investigated the magnetic properties of polycrystalline Y bRu(2)(Ge(1 - x)Si(x))(2) samples using magnetic susceptibility, electrical resistivity, and specific heat measurements. All the results indicate that the Yb ions in Y bRu(2)(Ge(1 - x)Si(x))(2) are in a stable trivalent state. The antiferromagnetic ordering shifts to lower temperature with increasing Si concentration (x).

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Paced rhythms can mask ECG changes of several conditions. ECG changes due to hyperkalemia during paced rhythm have not been well described. We report a patient with isolated noncompaction of left ventricle with left ventricular dysfunction and complete heart block on a permanent pacemaker who developed hyperkalemia.

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Superconductivity is found in 50% K-doped EuFe(2)As(2) samples below 33 K. Our results from electrical resistivity, magnetic susceptibility and (57)Fe and (151)Eu Mössbauer spectroscopy provide clear evidence that the ordering of the Fe moments observed at 190 K in undoped EuFe(2)As(2) is completely suppressed in our 50% K-doped sample; thus there is no coexistence of the Fe magnetic order and the superconducting state. However, short range ordering of the Eu moments coexists with the superconducting state below 15 K.

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We have grown single crystals of YbNiB(4) using a Ni(60)B(40) flux and determined the magnetic properties of this compound by means of magnetic susceptibility, specific heat and electrical resistivity measurement. Yb ions in YbNiB(4) are in a trivalent state and present a transition from a paramagnetic state to an antiferromagnetic (AF) state at T(N1) = 5.4 K and a further transition towards a second AF state at T(N2) = 4.

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Mesenteric artery embolism is a rare and an acute abdominal emergency with a very high mortality rate which requires a high index of suspicion for its diagnosis. We hereby report a 55 years old male with rheumatic heart disease in atrial fibrillation with thromboembolic superior mesenteric artery occlusion with a fatal outcome.

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Bilateral coronary artery to pulmonary artery fistulas is an uncommon congenital anomaly. These fistulas have a clinical and embryological significance. We report a rare case of combination of right coronary and left circumflex coronary fistula draining into main pulmonary artery, who presented in the emergency room with acute pain chest.

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Electron spin resonance (ESR) measurements of the ferromagnetic (FM) Kondo lattice system CeRuPO show a well defined ESR signal which is related to the Ce3+ magnetism. In contrast, no ESR could be observed in the antiferromagnetic (AFM) homologue CeOsPO. Additionally, we detect an ESR signal in ferromagnetic YbRh while it was absent in a number of Ce or Yb intermetallic compounds with dominant AFM exchange.

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