Anomalous magnetoresistance and magneto-thermal properties of the half-Heuslers,RPdSi (R=Y, Gd-Er).

Here, we present a detailed study on the magnetic, magneto-transport, and magneto-thermal properties of the equiatomic half-Heusler compounds with the general formula,RPdSi (R= Y and rare-earth, Gd-Er). These materials crystallize in two different superstructures of the TiNiSi-type orthorhombic unit cell with the space groupsPnmaandPmmn. Our magnetic and heat capacity measurements reveal the onset of an antiferromagnetic (AFM) ordering in the temperature range 3-16 K for all the local moments bearingRPdSi compounds, while the non-magnetic analog, YPdSi exhibits a Pauli-paramagnetic behaviour. The AFM state of these compounds can be tuned by magnetic field and temperature as demonstrated by the magnetic measurements below the Neel temperature (TN). Most importantly, this tuning of the magnetic structure is well documented in the complex temperature and field dependence of magnetoresistance (MR) and magnetocaloric effect (MCE). Our study establishes a striking correlation of the commensurate/incommensurate AFM structure with that of positive/negative MR and MCE in this series of compounds. We emphasize that such a framework applies to a large number of AFM intermetallic systems.

A Rare Case of Giant Cell Tumour of Bilateral Achilles Tendon Sheath - Reconstruction with Dual Tendon Transfer: A Case Report.

Giant cell tumour of tendon sheath is a benign soft tissue lesion most commonly found in the flexor aspect of hand and wrist. However, it is uncommon in foot and ankle and rare in bilateral achilles tendon. We report a case of 17-year-old female who presented with progressive enlargement of bilateral achilles tendon for six months. MRI findings showed that most of the tumour had intermediate to low signal intensity. Histopathology confirmed the diagnosis of giant cell tumour of tendon sheath. To help the patient regain the strength of the achilles tendon and walking abilities, a large area of tendon tumour was excised, followed by reconstruction with transfer of the peroneus brevis (PB) and posterior tibial (PT) tendon autograft. At two years follow-up, functional result was satisfactory.

Light Emitting Spin Active Electronic States in Ultra-Thin Mn Doped CdSe Layered Nanosheets.

The layered nanosheets exhibit a variety of physical and optical properties originating from amalgamation of intra- and inter- layer electronic interactions, which makes them promising materials for advanced devices with varsatile controlling channels. In particular, the dilute magnetic semiconductor multilayered nanosheets have promising optical, electrical and magnetic properties that have been less explored so far. Here, the spin permissible optical properties from solvothermally grown Mn doped CdSe (thickness ~2.26 nm) multilayered nanosheets are reported on. The presence of multi-phase magnetic orderings with a sharp ferromagnetic transition at temperature ~48 K pertinent to the stabilization and co-existence of Mn2+ and Mn3+ based local phases have been observed from the (Cd,Mn)Se layered nanosheets corroborating to the x-ray absorption near edge structure, electron paramagnetic resonance, Raman scattering and magnetic measurements. The optical absorption and photoluminescence (PL) studies at room temperature affirm wide array of optical properties in the visible regime corresponding to the band edge and intriguing dopant-phase mediated spin approved transitions. The circularly polarized magneto-PL and life time analysis exhibits the spin-polarized fast radiative transitions confirming the presence of spin-active electronic states.

Modulatory effect of 900 MHz radiation on biochemical and reproductive parameters in rats.

In the present study, the effect of 900 MHz radiation exposure on blood biochemical and reproductive parameters was evaluated in adolescent rats. Male albino Wistar rats (8-10 weeks of age) were exposed to 900 MHz radiation (1hr/day, power density - 146.60 µW/cm2) from a mobile phone for 28 days. On 29th day the animals were euthanized and malondialdehyde (MDA), total antioxidants (TA) levels and Glutathione-S transferase (GST) activity were studied in the blood. Reproductive parameters such as total sperm count, percentage of non-motile sperms, and sperm morphology were determined. Testes sections were stained with H(et)E staining and their cellular integrity was evaluated. Caspase-3 activity in the testes was also determined. MDA concentration was increased but TA levels and GST activity were not found to be different in 900 MHz group compared to controls. Sperm motility was found to be slightly reduced in 900 MHz group. Percentage of abnormal sperm was significantly elevated in 900 MHz group. Additionally, loss of germ cells particularly spermatocytes and spermatids was found in the testes of 900 MHz group. Testes caspase-3 activity was slightly elevated in 900 MHz exposed rats. Chronic 900 MHz exposure induced oxidative damage in the blood and lead to alterations in reproductive parameters in rats (Fig. 4, Ref. 33).

Long-range antiferromagnetic order and possible field induced spin-flop transition in BiMnVO5.

We report the bulk magnetic characterization of a dimeric chain material, BiMnVO5, by means of magnetic susceptibility, magnetization and heat capacity measurements. Our results provide compelling evidence of an antiferromagnetic (AFM) transition at (T N) ~ 11.5 K. Moreover, the magnetic entropy change in zero field saturates to 14.6 J mol-1 K-1 which is close to the total spin entropy of Mn2+. The development of long-range magnetic order in this chain material demonstrates the interplay of strong intra-chain and inter-chain interactions between the dimers, in addition to the intra-dimer interaction. Low-temperature (T < T N) heat capacity data indicate the presence of a gap (Δ/k B ≈ 5 K) in the spin excitations. Furthermore, the isothermal magnetization below T N shows an anomaly in the slope between 30 and 40 kOe which is suggestive of a spin-flop transition. Such a low-field spin-flop transition and gapped spin wave excitations may be attributed to the presence of (weak) magnetic anisotropy in this material. We attempt to construct a phase diagram in the magnetic field-temperature plane by extracting data from in-field heat capacity and isothermal magnetization measurements.

Displacive-type ferroelectricity from magnetic correlations within spin-chain.

Observation of ferroelectricity among non-d(0) systems, which was believed for a long time an unrealistic concept, led to various proposals for the mechanisms to explain the same (i.e. magnetically induced ferroelectricity) during last decade. Here, we provide support for ferroelectricity of a displacive-type possibly involving magnetic ions due to short-range magnetic correlations within a spin-chain, through the demonstration of magnetoelectric coupling in a Haldane spin-chain compound Er2BaNiO5 well above its Néel temperature of (TN = ) 32 K. There is a distinct evidence for electric polarization setting in near 60 K around which there is an evidence for short-range magnetic correlations from other experimental methods. Raman studies also establish a softening of phonon modes in the same temperature (T) range and T-dependent x-ray diffraction (XRD) patterns also reveal lattice parameters anomalies. Density-functional theory based calculations establish a displacive component (similar to d(0)-ness) as the root-cause of ferroelectricity from (magnetic) NiO6 chain, thereby offering a new route to search for similar materials near room temperature to enable applications.

A reentrant phenomenon in magnetic and dielectric properties of Dy2BaNiO5 and an intriguing influence of external magnetic field.

We report that the spin-chain compound Dy2BaNiO5, recently proven by us to exhibit magnetoelectric coupling below its Néel temperature (TN) of 58 K, exhibits strong frequency-dependent behavior in ac magnetic susceptibility and complex dielectric properties at low temperatures (<10 K), mimicking the 'reentrant' multiglass phenomenon. Such a behavior is not known among undoped compounds. A new finding in the field of multiferroics is that the characteristic magnetic feature at low temperatures moves towards higher temperatures in the presence of a magnetic field (H), whereas the corresponding dielectric feature shifts towards lower temperatures with H, unlike the situation near TN. This observation indicates that the alignment of spins by external magnetic fields tends to inhibit glassy-like slow electric-dipole dynamics, at least in this system, possibly arising from peculiarities in the magnetic structure.

Modifying cyclosporine associated renal allograft dysfunction.

Transplantation is accepted therapy for chronic kidney disease. However the essential immunosuppressive agents for graft survival have their own side-effects. Renal biopsy is a reliable tool for diagnosing cyclosporine (CsA) nephrotoxicity. To present our observations on CsA toxicity in renal allograft biopsies, we studied prospectively 207 renal allograft biopsies performed for graft dysfunction as per Ahmedabad Tolerance Induction Protocol (ATIP) and compared them to 50 controls from January to October 2007. The ATIP comprised donor specific leucocyte infusions, low dose target specific irradiation; non-myeloablative condi-tioning with Anti-T +/- B cell antibodies followed by intraportal administration of cultured donor bone marrow (BM) +/- adipose tissue derived mesenchymal stem cells. Renal transplantation was performed following negative lymphocytotoxicity cross-matching. The post-transplant immunosuppressive agents included CsA 2.5 +/- 0.5 mg/kg BW/day and prednisone 0.2 mg/kg BW/day. The controls were transplanted using standard triple immunosuppressive agents including CsA 5 +/- 1 mg/Kg BW/day, prednisone 0.6 mg/kg BW/day, and MMF/ Azathioprine. The Institutional Review Board approved the ATIP. The biopsies were categorized into 2 groups; group A (N=97): performed < 6 months, group B (N= 160), > 6 months posttransplant. Acute CsA toxicity was observed in group A: 2.5% ATIP and 11.1% controls; group B: 16.2% ATIP and 8.8% controls. Chronic CsA toxicity was observed in group B: 10.8 % ATIP and 17.6 % controls. Acute toxicity was more in the ATIP, while chronic toxicity was more in the controls. CsA doses were reduced post-biopsy and resulted in improved graft function evaluated by serum creatinine. We conclude that CsA nephrotoxicity evaluated by allograft biopsy resulted in allograft function recovery by decreasing the cyclosporine dose, and the ATIP decreased the incidence of CsA nephrotoxicity.

Changing trends of Candida species in neonatal septicaemia in a tertiary North Indian hospital.

Four hundred and fifty four blood samples of clinically diagnosed septicemic neonates were collected over a period of six months from the neonatal ICU of Kalawati Saran Children Hospital, New Delhi. 144 samples were culture positive; out of which 50 (34.7%) were Candida isolates. 92% isolates were Candida tropicalis, 4% were C. albicans and C. kefyr each. The study emphasises the changing pattern of Candida species and their importance in blood stream infections in neonates.

Insulin-like growth factor I and insulin-like growth factor binding protein 5 in Crohn's disease.

Insulin-like growth factor (IGF)-I and its binding protein IGF binding protein 5 (IGFBP-5) were highly expressed in inflamed and fibrotic intestine in experimental Crohn's disease. IGF-I induced proliferation and increased collagen synthesis by smooth muscle cells and fibroblasts/myofibroblasts in vitro. Here we studied IGF-I and IGFBP-5 in Crohn's disease tissue. Tissue was collected from patients undergoing intestinal resection for Crohn's disease. IGF-I and IGFBP-5 mRNAs were quantitated by RNase protection assay and Northern blot analysis, respectively. In situ hybridization was performed to localize mRNA expression, and Western immunoblot was performed to quantitate protein expression. IGF-I and IGFBP-5 mRNAs were increased in inflamed/fibrotic intestine compared with normal-appearing intestine. IGF-I mRNA was expressed in multiple cell types in the lamina propria and fibroblast-like cells of the submucosa and muscularis externa. IGFBP-5 mRNA was highly expressed in smooth muscle of the muscularis mucosae and muscularis externa as well as fibroblast-like cells throughout the bowel wall. Tissue IGFBP-5 protein correlated with collagen type I (r = 0.82). These findings are consistent with a mechanism whereby IGF-I acts on smooth muscle and fibroblasts/myofibroblasts to increase collagen synthesis and cellular proliferation; its effects may be modulated by locally expressed IGFBP-5.

IGF-I and procollagen alpha1(I) are coexpressed in a subset of mesenchymal cells in active Crohn's disease.

This study tested the hypothesis that insulin-like growth factor I (IGF-I) expression is increased at sites of fibrosis in diseased intestine of patients with Crohn's disease (CD). IGF-I mRNA was quantified by RNase protection assay in uninvolved and involved intestine of 13 CD patients (10 ileum, 3 colon) and 7 ulcerative colitis (UC) patients (colon). In situ hybridization histochemistry compared the localization of IGF-I and procollagen alpha1(I) mRNAs. Masson's trichrome staining and immunohistochemistry for IGF-I precursor, alpha-smooth muscle actin (A), vimentin (V), desmin (D), and c-kit were used to examine the mesenchymal cell subtypes that express IGF-I and collagen in uninvolved and involved ileum and colon of CD patients and "normal" ileum and colon from noninflammatory controls. IGF-I mRNA was elevated in involved ileum and colon of patients with CD but not in involved colon of patients with UC. IGF-I and procollagen alpha1(I) mRNA showed overlapping distribution within fibrotic submucosa and muscularis propria of involved CD ileum and colon. In involved CD intestine, increased IGF-I precursor expression localized to mesenchymal cells in regions of tissue disorganization and fibrosis in muscularis mucosa, submucosa, and muscularis propria. In these regions, there were increased numbers of V(+) cells relative to normal or uninvolved intestine. Increased IGF-I expression was localized to cells with a phenotype typical of fibroblasts (V(+)/A(-)/D(-)), myofibroblasts (V(+)/A(+)/D(+)), and, to a lesser extent, cells with normal enteric smooth muscle phenotype (V(-)/A(+)/D(+)). We conclude that increased IGF-I expression in multiple mesenchymal cell subtypes and increased numbers of cells with fibroblast/myofibroblast phenotype are involved in fibrosis associated with CD.

Insulin-like growth factor-I is expressed by avian flexor tendon cells.

Cells in normal tendon are in a resting G0 state, performing maintenance functions. However, traumatic injury introduces growth factors such as platelet-derived growth factor and insulin-like growth factor from blood as well as activates endogenous growth factors. These factors stimulate migration and proliferation of tendon cells at the wound area. Tendon cells require growth-promoting factors to transit the cell cycle. To evaluate the contribution of endogenous growth factors in tendon, extracts of the epitenon and internal compartment of avian flexor tendon as well as medium of cultured cells from the epitenon (tendon surface cells) and internal tendon (tendon internal fibroblasts) were collected to assess their ability to stimulate DNA synthesis. Acid-ethanol extracts of tissues and medium were chromatographed on a P-30 molecular sieve column and assayed for mitogenic activity by quantitating [3H]thymidine incorporation into tendon cell DNA. The extract from the internal tendon compartment was more stimulatory for DNA synthesis than that from the epitenon, particularly when tested on tendon internal fibroblasts. However, conditioned medium fractions from surface epitenon cells stimulated DNA synthesis to a high degree on both tendon surface cells and tendon internal fibroblasts. Conditioned medium from tendon internal fibroblasts was also stimulatory. An anti-insulin-like growth factor-I antibody ablated most of the mitogenic activity present in both tissues and conditioned medium. The levels of acid-extractable insulin-like growth factor-I in tendon were determined by competitive radioimmunoassay as 1.48+/-0.05 ng/g tissue for the epitenon and 3.83+/-0.03 ng/g tissue for the internal compartment. Results of Western immunoblots of conditioned medium revealed insulin-like growth factor-I at the 7.5 kDa position. Cultured tendon surface cells and tendon internal fibroblasts as well as cells in intact flexor tendon expressed insulin-like growth factor-I mRNA detected by reverse transcriptase-polymerase chain reaction. In situ hybridization histochemistry positively identified insulin-like growth factor-I mRNA in tendons from 52-day-old chickens. Platelet-derived growth factor was not detected at the protein or message levels. Furthermore, tendon surface cells and tendon internal fibroblasts both expressed receptors for insulin-like growth factor-I detected by flow cytometry. These data suggest that tendon cells express insulin-like growth factor-I mRNA and synthesize insulin-like growth factor-I in both the epitenon and the internal compartment of tendon, which is present in an inactive form, most likely bound to insulin-like growth factor-binding proteins.

Enterotrophic effect of insulin-like growth factor-I but not growth hormone and localized expression of insulin-like growth factor-I, insulin-like growth factor binding protein-3 and -5 mRNAs in jejunum of parenterally fed rats.

BACKGROUND: Administration of insulin-like growth factor (IGF)-I, but not growth hormone (GH), stimulates mucosal hyperplasia in surgically stressed rats with intestinal atrophy induced by hypocaloric total parenteral nutrition (TPN). Our aim was to characterize the basis for this disparity in enterotrophic action by assessing the relationships between stimulation of intestinal growth, nutritional adequacy, and localization of expression of IGF-I, insulin-like growth factor binding protein (IGFBP)-3 and IGFBP-5 mRNAs in jejunum. METHODS: Rats were maintained with TPN for 8 days and treated with IGF-I or GH and adequate nutrition for 5 days after recovery from surgery. Jejunal mass, morphology, and sucrase activity were assessed. Localization of expression of IGF-I, IGFBP-3, and IGFBP-5 mRNAs in jejunum was accomplished by in situ hybridization. RESULTS: Serum IGF-I and body weight gain were significantly increased by IGF-I or GH. Jejunal mucosal dry mass, morphology, and sucrase activity were improved with IGF-I but not GH. There were no differences in IGF-I mRNA. IGFBP-3 mRNA was localized in the lamina propria of the villi. IGF-I or GH stimulated IGFBP-3 expression. IGF-I strongly stimulated IGFBP-5 expression in the lamina propria and the muscularis and induced a twofold increase in IGFBP-5 mRNA based on RNase protection assay of intact jejunum total RNA. GH induced a modest increase in IGFBP-5 expression in the muscularis with no effect on intact jejunum total RNA. CONCLUSIONS: The GH resistance observed in the jejunal mucosa of TPN rats cannot be fully explained by inadequate nutrition. The expression of IGFBP-5 in the lamina propria suggests it may modulate the enterotrophic action of exogeneous IGF-I.

Differential expression and localization of IGF-I and IGF binding proteins in inflamed rat colon.

Recent studies indicate increased insulin-like growth factor I (IGF-I) expression and altered expression of IGF binding proteins (IGFBP) in the bowel during experimental colitis. This study analyzes the cellular sites of altered IGF-I and IGFBP-expression in large bowel of rats with experimental colitis. Colitis was induced by colonic instillation of 2, 4, 6-trinitrobenzenesulfonic (TNB) acid in ethanol. Animals were sacrificed at 7 days after induction of colitis. Cryostat sections of colon from TNB-treated and control rats were hybridized with 35S-labeled antisense probes for IGF-I, IGFBP-3, IGFBP-4 and IGFBP-5. IGF-I mRNA was up-regulated in lamina propria cells, submucosa and smooth muscle of inflamed colon. IGFBP-3 mRNA was localized to lamina propria and was down-regulated in inflamed colon. IGFBP-4 and IGFBP-5 mRNAs were both up-regulated in inflamed colon. IGFBP-4 mRNA was increased in lamina propria, submucosa and smooth muscle, whereas IGFBP-5 mRNA was increased in smooth muscle. Increased IGF-I expression in mesenchymal layers of colon during experimental colitis supports the hypothesis that IGF-I contributes to hyperplasia and fibrosis in response to inflammation. Altered expression of IGFBP-3, IGFBP-4 and IGFBP-5 in specific bowel layers during colitis suggests that they play a role in modulating IGF-I action.

Alteration of sulfation of glycoconjugates, but not sulfate transport and intracellular inorganic sulfate content in cystic fibrosis airway epithelial cells.

The secreted and cell surface high molecular weight glyco-conjugates (HMG) generated by primary cultures of airway epithelial cells from cystic fibrosis (CF) patients are oversulfated. To determine whether this abnormality is maintained in transformed CF airway epithelial cells and whether differences in transport or intracellular accumulation of sulfate can explain this alteration, we assessed sulfate metabolism in paired CF and normal cell lines as well as primary cultures of CF and normal cells. Both 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid-inhibitable and -resistant [35S]sulfate efflux and influx were identical for each pair of CF and normal cell lines. Furthermore, cell content of inorganic sulfate was not significantly different in CF and normal cells. However, compared with primary CF cells that oversulfate HMG transformed CF cells oversulfated cell surface HMG but not HMG released into culture medium. Our results suggest that plasma membrane sulfate transport is not altered in CF airway epithelial cells and the abnormal sulfation of HMG may be due to perturbation in intracellular sulfate activation or transfer of activated sulfate to HMG. The relationship of this abnormality to CF transmembrane conductance regulator mutations remains to be determined.

Regulation and localization of the insulin-like growth factor system in small bowel during altered nutrient status.

Insulin-like growth factor-I (IGF-I) may regulate small bowel growth. Analyses here in ad libitum-fed, fasted, and refed rats demonstrate that during fasting and refeeding changes in jejunal mass correlate with changes in serum IGF-I and jejunal IGF-I mRNAs. These data indicate that circulating and locally expressed IGF-I contribute to nutrient regulation of jejunal mass. During refeeding, jejunal IGF binding protein 3 (IGFBP-3) mRNA abundance was reduced relative to that of IGF-I, possibly amplifying enterotrophic actions of IGF-I. Localization of IGFBP-3 to subepithelial cells in lamina propria of jejunum indicates that IGFBP-3 derived from lamina propria may modulate IGF-I action on adjacent epithelium. Ileum differed from jejunum in that refeeding did not increase bowel mass or IGF-I mRNA to ad libitum values. Differences in exposure to luminal nutrient may underlie distinct responses of the two segments. Rats fed elemental diet intravenously showed reduced jejunal mass but not reduced jejunal IGF-I mRNA compared with rats fed oral elemental diet. Elemental nutrient given intravenously or orally therefore does not differ in effects on jejunal IGF-I expression. Complex luminal nutrient may, however, regulate jejunal IGF-I expression.

Sulfate concentrations and transport in human bronchial epithelial cells.

Inorganic sulfate concentrations in the cytoplasm of human bronchial epithelial cells exceeded levels in the bathing medium under all circumstances tested. Cell sulfate concentrations were directly related to medium sulfate concentrations and inversely related to medium chloride concentrations. In physiological media there was a sulfate compartment of approximately 0.3 mM that exchanged very slowly with extracellular sulfate. In media lacking chloride, sulfate was accumulated by the cells to a level as high as 2 mM. Sulfate uptake was markedly inhibited by external chloride and by stilbene sulfonic acid derivatives but was not affected by sodium in the medium. Efflux of 35SO4(2-) was stimulated by both chloride and sulfate in the bathing medium but inhibited by stilbenes. The following compounds had no effect on sulfate movements: phorbol esters, adenosine 3',5'-cyclic monophosphate derivatives, and okadaic acid. Changes in medium tonicity were likewise without effect. Our results suggest that human bronchial epithelial cells maintain a steady-state disequilibrium for inorganic sulfate. Furthermore, sulfate appears to exist in at least two compartments in the cells: one that is slowly exchangeable with sulfate in the medium and another exchangeable compartment that is of negligible size in physiological media but that becomes very large in media lacking chloride. Sulfate is transported by an anion exchanger of broad specificity that is not influenced by substances known to modulate chloride channels.

Colchicine enhances mRNAs encoding the precursor of calcitonin gene-related peptide in brainstem motoneurons.

Hybridization signals indicating mRNAs encoding the precursor of calcitonin gene-related peptide (CGRP) and CGRP immunoreactivity were detected on parallel sections containing brainstem motor nuclei using in situ hybridization histochemistry and immunohistochemistry. In untreated and saline-injected rats the motoneurons in the hypoglossal, facial motor nuclei and in the ambiguus nucleus showed weak to moderate hybridization signals. In these motoneurons CGRP immunoreactivity was restricted to the Nissl bodies of the perikarya. Twenty-four and 42 hours after intracerebroventricular colchicine injection the intensity of both the hybridization signal and the immunoreaction product increased. The distribution of CGRP immunoreactivity changed from discrete perikaryal localization to diffuse reaction in the perikarya and along the proximal dendritic tree. Motoneurons in the rest of the brainstem motor nuclei (VIth, Vth, IVth and IIIrd) of untreated and saline-injected rats showed neither hybridization signal nor CGRP immunoreactivity. After intracerebroventricular injection of colchicine these motoneurons showed both hybridization signal and CGRP immunoreactivity. In all nuclei the size of motoneurons decreased and their Nissl structure changed to an amorphous basophilic mass following colchicine treatment.