Charge-ordering breakdown dynamics and ferromagnetic resonance studies ofB-site Cu diluted Pr1‒xSrxMnO3.

Here, we report the influence of Jahn-Teller active Cu substitution on the charge-ordering (CO) characteristics of one of the well-known manganite Pr0.45Sr0.55MnO3(S55) with a distorted tetragonal structure. Magnetization studies unveil a complex magnetic phase diagram for S55, showing distinct temperature ranges corresponding to various magnetic phases: a ferromagnetic phase dominated by the Double Exchange interaction withTC∼ 220.5 K, an antiferromagnetic phase belowTN∼ 207.6 K induced by CO with a transition temperature ofTCO∼ 210 K consistent with the specific heatCP(T) data, and a mixed phase in the rangeTNTN(T

Magnetic exchange interactions and non-Debye relaxation in spin-3/2 frustrated Kagomé magnet Co3V2O8.

We report the experimental determination of the magnetic exchange parameter (J/kB= 2.88 ± 0.02 K) for the Spin-3/2 ferromagnetic (FM) Kagomé lattice system: Co3V2O8using the temperature dependence of dc-magnetic susceptibilityχ(T) data by employing the fundamental Heisenberg linear chain model. Our results are quite consistent with the theoretically reported nearest neighbor dominant FM exchange coupling strengthJex-NN∼2.45 K. Five different magnetic phase transitions (6.2-11.2 K) and spin-flip transitions (9.6-7.7 kOe) have been probed using the∂(χT)/∂Tvs.T, heat capacity (CP-T) and differential isothermal magnetization curves. Among such sequence of transitions, the prominent ones being incommensurate antiferromagnetic (AFM) state at 11.2 K, commensurate AFM state at 8.8 K, and commensurate FM state across 6.2 K. All the successive magnetic phase transitions have been mapped onto a single H-T plane through which one can easily distinguish the above-mentioned different phases. The magnetic contribution of theCP-TnearTN(11.2 K) has been analyzed using the power-law expressionCM=A|T-TN|-αresulting in the critical exponentα= 0.18 ± 0.01 (0.15 ± 0.003) forTTN), respectively for the Co3V2O8. It is interesting to note that non-Debye type dipole relaxation is quite prominent in Co3V2O8and was evident from the Kohlrausch-Williams-Watts analysis of complex modulus and impedance spectra (0⩽ß⩽1). Mott's variable-range hopping of charge carriers process is evident through the resistivity analysis (ρac-T-1/4) in the temperature range 275 ∘C-350 ∘C. Moreover, the frequency-dependent analysis ofσac(ω) follows Jonscher's power law yielding two distinct activation energies (Ea∼0.37 and 2.29 eV) between the temperature range 39 ∘C-99 ∘C and 240 ∘C-321 ∘C.

Reentrant canonical spin-glass dynamics and tunable field-induced transitions in (GeMn)Co2O4Kagomé lattice.

We report on the reentrant canonical semi spin-glass characteristics and controllable field-induced transitions in distorted Kagomé symmetry of (GeMn)Co2O4. ThisB-site spinel exhibits complicated, yet interesting magnetic behaviour in which the longitudinal ferrimagnetic (FiM) order sets in below the Néel temperatureTFN∼ 77 K due to uneven moments of divalent Co (↑ 5.33µB) and tetravalent Mn (↓ 3.87µB) which coexists with transverse spin-glass state below 72.85 K. Such complicated magnetic behaviour is suggested to result from the competing anisotropic superexchange interactions (JAB/kB∼ 4.3 K,JAA/kB∼ -6.2 K andJBB/kB∼ -3.3 K) between the cations, which is extracted following the Néel's expression for the two-sublattice model of FiM. Dynamical susceptibility (χac(f, T)) and relaxation of thermoremanent magnetization,MTRM(t) data have been analysed by means of the empirical scaling-laws such as Vogel-Fulcher law and Power law of critical slowing down. Both of which reveal the reentrant spin-glass like character which evolves through a number of intermediate metastable states. The magnitude of Mydosh parameter (Ω âˆ¼ 0.002), critical exponentzυ= (6.7 ± 0.07), spin relaxation timeτ0= (2.33 ± 0.1) × 10-18s, activation energyEa/kB= (69.8 ± 0.95) K and interparticle interaction strength (T0= 71.6 K) provide the experimental evidences for canonical spin-glass state below the spin freezing temperatureTF= 72.85 K. The field dependence ofTFobtained fromχac(T) follows the irreversibility in terms of de Almeida-Thouless mean-field instability in which the magnitude of crossover scaling exponent Φ turns out to be ∼2.9 for the (Ge0.8Mn0.2)Co2O4. Isothermal magnetization plots reveal two field-induced transitions across 9.52 kOe (HSF1) and 45.6 kOe (HSF2) associated with the FiM domains and spin-flip transition, respectively. Analysis of the inverse paramagnetic susceptibilityχp-1χp=χ-χ0after subtracting the temperature independent diamagnetic termχ0(=-3 × 10-3emu mol-1Oe-1) results in the effective magnetic momentµeff= 7.654µB/f.u. This agrees well with the theoretically obtainedµeff= 7.58µB/f.u. resulting the cation distributionMn0.24+↓A[Co22+↑]BO4in support of the Hund's ground state spin configurationS=3/2andS= 1/2of Mn4+and Co2+, respectively. TheH-Tphase diagram has been established by analysing all the parameters (TF(H),TFN(H),HSF1(T) andHSF2(T)) extracted from various magnetization measurements. This diagram enables clear differentiation among the different phases of the (GeMn)Co2O4and also illustrates the demarcation between short-range and long-range ordered regions.

Spin-liquid state with precursor ferromagnetic clusters interacting antiferromagnetically in frustrated glassy tetragonal spinel Zn0.8Cu0.2FeMnO4.

Spinels (AB2O4) with magnetic ions occupying only the octahedralBsites have inherent magnetic frustration which inhibits magnetic long-range order (LRO) but may lead to exotic states. Here we report on the magnetic properties of the tetragonal spinel Zn0.8Cu0.2FeMnO4, the tetragonality resulting from the Jahn-Teller active Mn3+ions. X-ray diffraction and x-ray photoelectron spectroscopy of the sample yielded the composition (Zn0.82+Cu0.22+)A[Fe0.42+Fe0.63+Mn3+]BO4‒δ. Analysis of the temperature dependence of magnetization (M), ac magnetic susceptibilities (χ'andχ''), dc susceptibility (χ), heat capacityCp, and neutron diffraction (ND) measurements show complex temperature-dependent short-range order (SRO) but without LRO. The data ofχ vs. Tfits the Curie-Weiss law:χ = C/(T ‒ θ) fromT= 250 K to 400 K withθ≃ 185 K signifying dominant ferromagnetic (FM) coupling with the FM exchange constantJ/kB= 17 K, andC= 3.29 emu K mol‒1Oe‒1yielding an effective magnetic momentµeff= 5.13µBresulting from the high-spin states of Cu2+(Asite) and Fe2+(Bsite), while theBsite trivalent ions Mn3+and Fe3+are in their low-spin states. The extrapolated saturation magnetization obtained from theM vs. Hdata atT= 2 K is explained using the spin arrangement (Cu2+↓)A[Fe2+↑, Fe3+↓, Mn3+↑]Bleading to FM clusters interact antiferromagnetically at low temperatures. Temperature dependence of d(χT)/dTshows the onset of ferrimagnetism below ∼100 K and peaks near 47 K and 24 K. The relaxation timeτobtained from temperature and frequency dependence ofχ″when fit to the power law and Vogel-Fulcher laws confirm the cluster spin-glass (SG) state. The magnetic field dependence of the SG temperatureTSGHfollows the equation:TSGH=TSG01-AH2/ϕwithTSG(0) = 46.6 K,A= 8.6 × 10‒3Oe‒0.593andϕ= 3.37. The temperature dependence of hysteresis loops yields coercivityHC∼ 3.8 kOe at 2 K without exchange-bias, butHCdecreases with increase inTbecoming zero above 24 K, theTSG(H) forH= 800 Oe. Variations ofCpvs. Tfrom 2 K to 200 K inH=0 andH=90 kOe do not show any peak characteristic of LRO. However, after correcting for the lattice contribution, a broad weak peak typically of SRO becomes evident centered around 40 K. ForT< 9 K,Cpvaries asT2; a typical signature of spin-liquids (SLs). Comparison of the ND measurements at 1.7 K and 79.4 K shows absence of LRO. Time dependence of thermo-remanent magnetizationMTRM(t) studies below 9 K reveal weakening of the inter-cluster interaction with increase in temperature. A summary of these results is that in Zn0.8Cu0.2FeMnO4, ferromagnetic clusters interact antiferromagnetically without LRO but producing a cluster SG state atTSG(0) = 46.6 K, followed by SL behavior below 9 K.

Glucometrics in the first week of critical illness and its association with mortality / Glucometría en la primera semana de enfermedad crítica y su asociación con la mortalidad

Objective Evaluation of glucometrics in the first week of ICU stay and its association with outcomes. Design Prospective observational study. Setting Mixed ICU of teaching hospital. Patients Adults initiated on insulin infusion for 2 consecutive blood glucose (BG) readings ≥180mg/dL. Main variables of interest Glucometrics calculated from the BG of first week of admission: hyperglycemia (BG>180mg/dL) and hypoglycemia (BG<70mg/dL) episodes; median, standard deviation (SD) and coefficient of variation (CV) of BG, glycemic lability index (GLI), time in target BG range (TIR). Factors influencing glucometrics and the association of glucometrics to patient outcomes analyzed. Results A total of 5762 BG measurements in 100 patients of median age 55 years included. Glucometrics: hyperglycemia: 2253 (39%), hypoglycemia: 28 (0.48%), median BG: 169mg/dL (162–178.75), SD 31mg/dL (26–38.75), CV 18.6% (17.1–22.5), GLI: 718.5 [(mg/dL)2/h]/week (540.5–1131.5) and TIR 57% (50–67). Diabetes and higher APACHE II score were associated with higher SD and CV, and lower TIR. On multivariate regression, diabetes (p=0.009) and APACHE II score (p=0.016) were independently associated with higher SD. Higher SD and CV were associated with less vasopressor-free days; lower TIR with more blood-stream infections (BSI). Patients with higher SD, CV and GLI had a higher 28-day mortality. On multivariate analysis, GLI alone was associated with a higher mortality (OR 2.99, p=0.04). Conclusions Glycemic lability in the first week in ICU patients receiving insulin infusion is associated with higher mortality. Lower TIR is associated with more blood stream infections (AU)

Objetivo Evaluación de la glucometría en la primera semana de estancia en la UCI y su asociación con los resultados. Diseño Estudio observacional prospectivo. Ámbito UCI mixta de hospital docente. Pacientes Adultos que iniciaron una infusión de insulina para dos lecturas consecutivas de glucosa en sangre (GS) ≥180mg/dl. Principales variables de interés Glucometría calculada a partir de la GS de la primera semana de ingreso: episodios de hiperglucemia (GS >180mg/dl) e hipoglucemia (GS <70mg/dl); mediana, desviación estándar (DE) y coeficiente de variación (CV) de GS, índice de labilidad glucémica (ILG), tiempo en el rango objetivo de GS (TIR). Resultados Se incluyeron un total de 5.762 GS en 100 pacientes con una mediana de edad de 55años. Glucometría: hiperglucemia: 2.253 (39%), hipoglucemia: 28 (0,48%), mediana GS: 169mg/dl, DE 31mg/dl, CV 18,6%, ILG: 718,5 [(mg/dl)2/h]/semana, TIR 57%. La diabetes y una puntuación APACHEII más alta se asociaron con una DE y un CV más altos y una TIR más baja. En la regresión multivariada, la diabetes (p=0,009) y la puntuación APACHEII (p=0,016) se asociaron de forma independiente con una DE más alta. La DE y el CV más altos se asociaron con menos días sin vasopresores; menor TIR, con más infecciones del torrente sanguíneo (ITS). En el análisis multivariado, el ILG solo se asoció con una mayor mortalidad (OR: 2,99, p=0,04). Conclusiones La labilidad glucémica en la primera semana en pacientes de UCI que reciben infusión de insulina se asocia con mayor mortalidad. Una TIR más baja se asocia con más ITS (AU)

Glucometrics in the first week of critical illness and its association with mortality.

OBJECTIVE: Evaluation of glucometrics in the first week of ICU stay and its association with outcomes. DESIGN: Prospective observational study. SETTING: Mixed ICU of teaching hospital. PATIENTS: Adults initiated on insulin infusion for 2 consecutive blood glucose (BG) readings ≥180mg/dL. MAIN VARIABLES OF INTEREST: Glucometrics calculated from the BG of first week of admission: hyperglycemia (BG>180mg/dL) and hypoglycemia (BG<70mg/dL) episodes; median, standard deviation (SD) and coefficient of variation (CV) of BG, glycemic lability index (GLI), time in target BG range (TIR). Factors influencing glucometrics and the association of glucometrics to patient outcomes analyzed. RESULTS: A total of 5762 BG measurements in 100 patients of median age 55 years included. Glucometrics: hyperglycemia: 2253 (39%), hypoglycemia: 28 (0.48%), median BG: 169mg/dL (162-178.75), SD 31mg/dL (26-38.75), CV 18.6% (17.1-22.5), GLI: 718.5 [(mg/dL)2/h]/week (540.5-1131.5) and TIR 57% (50-67). Diabetes and higher APACHE II score were associated with higher SD and CV, and lower TIR. On multivariate regression, diabetes (p=0.009) and APACHE II score (p=0.016) were independently associated with higher SD. Higher SD and CV were associated with less vasopressor-free days; lower TIR with more blood-stream infections (BSI). Patients with higher SD, CV and GLI had a higher 28-day mortality. On multivariate analysis, GLI alone was associated with a higher mortality (OR 2.99, p=0.04). CONCLUSIONS: Glycemic lability in the first week in ICU patients receiving insulin infusion is associated with higher mortality. Lower TIR is associated with more blood stream infections.

Revisiting extra hepatic portal vein obstruction in children from the north Indian gangetic plain.

OBJECTIVES: To study the demographic features, etiology, clinical, radiology and laboratory findings in children with Extra hepatic portal vein obstruction (EHPVO) from the North Indian Gangetic Plain. METHODS: A prospective analysis of 53 patients of EHPVO (<14 y of age) was done. Data for clinical presentation, laboratory workup, endoscopic procedures, growth and development, management and outcome were analyzed. RESULTS: A total of 53 patients (32 male, 21 female) with mean age of 8.66 ± 3.32 y at presentation were included. Growth retardation was present in 30 (56.60 %) patients at time of diagnosis. The most common presenting symptoms were upper gastrointestinal bleeding (86.80 %) and an incidental finding of splenomegaly (13.2 %). Hematological parameters of hypersplenism were present in 9 (17 %) patients. Protein C (PC), Protein S (PS), antithrombin III (AT) deficiency were found in 8 (20 %), 4 (10 %) and 6 (15 %) of the patients respectively in 40 patients tested. On first endoscopy, esophageal varices were present in all patients. Endoscopic sclerotherapy (EST)/band ligation (EBL) was performed in 46 bleeder patients and success rate was 83.3 % for sclerotherapy and 90 % for band ligation. CONCLUSIONS: The etiology of EHPVO in the majority of patients remains elusive. It results in impaired somatic growth. Sclerotherapy and endoscopic banding are effective means for treatment for bleeding varices. It is still not clear whether deficiency of anticoagulant proteins is a primary event or secondary to disease process.

A Training Aid for IV Access.

Starting intravenous drip is one of the first steps in the treatment of a patient. Training is the key to attain proficiency to get intravenous access.

Surgical treatment of plantar ulcers in leprosy.

Plantar ulcers present a serious problem in the management of leprosy. After studying the mechanism of ulceration and the causes of their indolence, it appears that the treatment of the disease by antileprotic drugs is not sufficient. The underlying causes, such as anaesthesia, bony deformities and paralysis, should usually be treated by surgical means. Anaesthesia can be reversed by decompression of the posterior tibial nerve if this is done early. Deformities should be corrected by procedures on the soft tissues or bones, and chronic infection eradicated to prevent recurrence of the ulceration. A combination of procedures may sometimes be needed.

Surgical treatment of plantar ulcers in leprosy.

Plantar ulcers present a serious problem in the management of leprosy. After studying the mechanism of ulceration and the causes of their indolence, it appears that the treatment of the disease by antileprotic drugs is not sufficient. The underlying causes, such as anaesthesia, bony deformities and paralysis, should usually be treated by surgical means. Anaesthesia can be reversed by decompression of the posterior tibial nerve if this is done early. Deformities should be corrected by procedures on the soft tissues or bones, and chronic infection eradicated to prevent recurrence of the ulceration. A combination of procedures may sometimes be needed.

Surgical treatment of plantar ulcers in leprosy

Plantar ulcers present a serious problem in the management of leprosy. After studying the mechanism of ulceration and the causes of their indolence, it appears that the treatment of the disease by antileprotic drugs is not sufficient. The underlying causes, such as anaesthesia, bony deformities and paralysis, should usually be treated by surgical means. Anaesthesia can be reversed by decompression of the posterior tibial nerve if this is done early. Deformities should be corrected by procedures on the soft tissues or bones, and chronic infection eradicated to prevent recurrence of the ulceration. A combination of procedures may sometimes be needed.