Scaling of domain cascades in stripe and skyrmion phases.

The origin of deterministic macroscopic properties often lies in microscopic stochastic motion. Magnetic fluctuations that manifest as domain avalanches and chaotic magnetization jumps exemplify such stochastic motion and have been studied in great detail. Here we report Fourier space studies of avalanches in a system exhibiting competing magnetic stripe and skyrmion phase using a soft X-ray speckle metrology technique. We demonstrate the existence of phase boundaries and underlying critical points in the stripe and skyrmion phases. We found that distinct scaling and universality classes are associated with these domain topologies. The magnitude and frequency of abrupt magnetic domain jumps observed in the stripe phase are dramatically reduced in the skyrmion phase. Our results provide an incisive way to probe and understand phase stability in systems exhibiting complex spin topologies.

Publisher Correction: Scaling of domain cascades in stripe and skyrmion phases.

The original version of this Article contained an error in Fig. 4d, in which the label of the region to the left of the white dashed lines incorrectly read 'Order stripes'. The correct version states 'Disorder stripes'. This has been corrected in both the PDF and HTML versions of the Article.

Breast Cancer with Paraneoplastic Syndrome in a 72 Year Old Male Patient.

Breast cancer in male is rare which accounts about 1% of all malignant breast neoplasm cases. Since paraneoplastic syndrome is unusual with male breast cancer, very few reported cases are found. A72- year-old gentleman presented with proximal myopathy in all four limbs was referred to Dr. Sirajul Islam Medical College and Hospital in April 2017. He had generalized wasting with reduced tone and reflexes. Planter responses were normal with intact sensory. There were typical Heliotrope rash bilaterally. In background, he had history of radical mastectomy due to stage IIA ductal carcinoma of left breast 7 years back. Three years later, he was found to have multiple metastases in lung and liver, however, deliberately discontinued chemotherapy after first dose. Currently he is on Tamoxifen. Two months back, he was diagnosed to have brain metastasis. Also his serum sodium level was low with low urine osmolality. Considering his background, we diagnosed him dermatomyositis with peripheal neuropathy & SIADH as paraneoplastic presentation of breast malignancy. Despite of normal CPK and NCV, we treated him with steroid as dermatomyositis can present with normal CPK. His myopathy improved after 2 weeks of steroid treatment. Fluid restriction increased his serum sodium level. The aim of reporting this case is to aware physicians about the aggressive nature of male breast cancer, its orthodox paraneoplastic presentation and to differentiate neuropathy from myopathy so that early treatment can improve the outcome.

Continuous Uptake or Saturation-Investigation of Concentration and Surface-Packing-Specific Hemin Interaction with Lipid Membranes.

Drug design and targeted delivery in cells serve as a flourishing area not only for scientific inquiry, owing to numerous clinical applications, but also for understanding cell interaction with exogenous materials. The membrane localization of heme and its analog hemin, one of the most biologically relevant planar organic molecule, is very important to understand the molecular mechanism of intercalation and adsorption of this cytotoxic molecule after its dissociation from proteins such as hemoglobin. Herein, we investigate the differential behavior of hemin on the soft membrane surfaces of phospholipids by synchrotron-based X-ray scattering techniques, Langmuir monolayer measurements, and molecular dynamics simulation. A continuous hemin uptake from the subphase and intercalation into and/or adsorption on to the membrane surface have been witnessed in a strong membrane surface packing-specific manner. Competitive interactions between hemin-membrane and hemin-hemin are proposed to be responsible for the critical hemin concentration. Up to the limit, a continuous hemin uptake is possible and beyond that the hemin-hemin interaction dominates, effectively reducing the hemin intercalation into the membrane. This structural model of the hemin-uptake process can be generalized to understand the localization and transport across membranes and also for the development and design of new drugs.

Reversible monolayer-to-crystalline phase transition in amphiphilic silsesquioxane at the air-water interface.

We report on the counter intuitive reversible crystallisation of two-dimensional monolayer of Trisilanolisobutyl Polyhedral Oligomeric SilSesquioxane (TBPOSS) on water surface using synchrotron x-ray scattering measurements. Amphiphilic TBPOSS form rugged monolayers and Grazing Incidence X-ray Scattering (GIXS) measurements reveal that the in-plane inter-particle correlation peaks, characteristic of two-dimensional system, observed before transition is replaced by intense localized spots after transition. The measured x-ray scattering data of the non-equilibrium crystalline phase on the air-water interface could be explained with a model that assumes periodic stacking of the TBPOSS dimers. These crystalline stacking relaxes upon decompression and the TBPOSS layer retains its initial monolayer state. The existence of these crystals in compressed phase is confirmed by atomic force microscopy measurements by lifting the materials on a solid substrate.

Structural reordering in monolayers of gold nanoparticles during transfer from water surface to solid substrate.

Structural reordering in monolayers of gold nanoparticles during transfer from water surface to solid substrate has been studied by synchrotron x-ray scattering techniques. Grazing incidence diffraction (GID) and grazing incidence x-ray off-specular scattering (GIXOS) measurements were performed as a function of time to track the in-plane and out-of-plane structural reordering in the transferred monolayers. GID measurements show shift in the in-plane particle-particle correlation peak toward the lower in-plane momentum transfer value, signifying possible expansion of triangular lattice formed on the water surface. However, GIXOS data and supportive microscopy measurements clearly show compactification in the in-plane structure and associated out-of-plane movements. A model that assumes the possibility of a two-dimensional short-range structural reordering from triangular to square-like lattice as a function of time could explain all the data. The observed change in the electron densities of the nanoparticles before and after the structural reordering matches well with the expected change in the calculated electron densities of the nanoparticles arranged in triangular (pretransition) and square-like (post-transition) symmetry.

Influence of stabilizers on quality of sandesh from buffalo milk.

Buffalo milk standardized to solids-not-fat (SNF) to fat ratio of 1.4 was added separately with 0.1% (w/w) each of carrageenan, sodium alginate and carboxymethyl cellulose and then heated, cooled and coagulated to obtain chhana which was converted into sandesh by adding 1.5% (w/w) wheat flour and 25% (w/w) cane sugar followed by heating (40 min/kg chhana). The treated samples of sandesh were compared with control prepared similarly manner but without stabilizer. Addition of stabilizer decreased hardness, fracturability, adhesiveness, cohesiveness, gumminess and chewiness of sandesh and improved sensory body and texture, colour and appearance as well as overall acceptability of the product when compared with control. Textural and sensory properties of different samples of sandesh indicated that the product made by adding carrageenan proved best. Carrageenan at 0.1% produced better results in terms of textural and sensory profile of sandesh as compared to 0, 0.075 and 0.125% (w/w) of carrageenan.

Nanopattern formation in self-assembled monolayers of thiol-capped Au nanocrystals.

The structure and the stability of the transferred monolayers of gold-thiol nanoparticles, formed at air-water interface at different surface pressure, on to silicon surface have been studied using two complementary techniques, x-ray reflectivity and atomic force microscopy (AFM). Networklike nanopatterns, observed through AFM, of the in-plane aggregated nanoparticles can be attributed to the late stage drying of the liquid trapped in the islands formed by nanoparticles. During drying process the trapped liquid leaves pinholes in the islands which by the process of nucleation and growth carry the mobile nanoparticles on their advancing fronts such that the nanoparticles are trapped at the boundaries of similar adjacent holes. This process continues bringing about in-plane as well as out-of-plane restructuring in the monolayer until the liquid evaporates completely rendering a patterned structure to the islands and instability in the monolayer is then stabilized.

Growth of bimolecular films of three-tailed amphiphiles.

The three-tailed amphiphile ferric stearate molecule, which forms a bimolecular layer on water surface with molecules in the lower and upper layers in different conformations, has been studied to understand transfer and growth of bimolecular films on the surface of hydrophilic silicon substrates. This bimolecular film forms a two-dimensional lattice on water with a slightly distorted hexagonal lattice where both the in-plane and out-of-plane domain sizes are small. The film also showed larger microscopic rigidity compared to its macroscopic mechanical response. This asymmetric bimolecular layer was found to be preserved when the film is transferred on the substrates at different values of surface pressures ranging from 1 mN/m to near-collapse (55 mN/m). Both the upper and lower layers become denser and interfaces between these layers become sharper with increase in deposition pressure but the growths have different natures. The lower layer of transferred film is dense from 1 mN/m and, except for a steplike increase between 20 and 30 mN/m, changes slowly in density. The density of the upper molecular layer grows continuously with surface pressure.

Dramatic enhancement of capillary wave fluctuations of a decorated water surface.

We have demonstrated by x-ray diffuse scattering that a bimolecular layer of a preformed three-tailed amphiphile, ferric stearate, drastically enhances capillary wave fluctuations on water surface due to a reduction in surface tension to 1 mN/m . The bimolecular layer is composed of molecules in symmetric configuration, on top of molecules in asymmetric configuration with ferric ions in contact with water. Unlike the usual Langmuir monolayers, this layer of molecules does not rupture under compression, but becomes thicker. This behavior mimics folding of a membrane on a liquid surface and is closely related to the cohesive interaction brought by the ferric ions. The low effective tension of this artificial membrane depends on the available area and reduces as the microscopic excess area increases.

Glass transition in ultrathin polymer films: a thermal expansion study.

The glass transition process gets affected in ultrathin films having thickness comparable to the size of the molecules. We observe systematic broadening of the glass transition temperature (T(g)) as the thickness of an ultrathin polymer film reduces below the radius of gyration but the change in the average T(g) was found to be very small. The existence of reversible negative and positive thermal expansion below and above T(g) increased the sensitivity of our thickness measurements performed using energy-dispersive x-ray reflectivity. A simple model of the T(g) variation as a function of depth expected from sliding motion could explain the results.

Reversible negative thermal expansion of polymer films.

A basic understanding of the properties of thin polymer films is of fundamental importance for developing applications in nanotechnology. Results of energy and angle dispersive x-ray reflectivity measurements on polymer thin films as a function of temperature exhibit reversible negative thermal expansion below the glass transition temperature T(g). Above T(g), the thickness expansion becomes almost equal to the expected bulk volume expansion. These results could be explained on the basis of evolution of disorder with temperature at the interfaces, chain entanglement and associated entropy changes.

Severe combined immunodeficiency mouse-human skin chimeras: a unique animal model for the study of psoriasis and cutaneous inflammation.

Elucidation of the molecular and cellular mechanisms responsible for the pathogenesis of psoriasis had been significantly handicapped due to lack of an ideal animal model. To overcome this hurdle several investigators have developed a number of animal models for psoriasis. Recent establishment of the SCID-human skin chimeras with transplanted psoriasis plaques has opened new vistas to study the molecular complexities involved in psoriasis. This model also offers a unique opportunity to investigate various key biological events such as cell proliferation, angiogenesis, homing in of T cells in target tissues, neurogenic inflammation and cytokine/chemokine cascades involved in an inflammatory reaction. The SCID mouse model will be of immense help to target the cellular and molecular events associated with these pathogenic processes and develop novel drugs for psoriasis and other inflammatory diseases. In this article we have reviewed the prospects and the limitations of the SCID mouse model of psoriasis.

Localization of nitric oxide synthase in human trophoblast cells: role of nitric oxide in trophoblast proliferation and differentiation.

PROBLEM: There are conflicting reports about the isoform of nitric oxide synthase (NOS) present in trophoblast cells. In this study, we have examined the presence of different NOS isoforms in trophoblast cells. In addition, the role of nitric oxide (NO) in trophoblast function has also been studied by investigating the possible role of nitric oxide in trophoblast proliferation and differentiation. METHOD OF STUDY: NOS isoforms in primary-term trophoblast and JEG-3 cells were identified by immunocytochemistry. The intracellular localization of this enzyme was determined by confocal laser scanning microscopy. Trophoblast proliferation was studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrasolium bromide (MTT) conversion assay and cellular differentiation was monitored by human chorionic gonodotropin (hCG) and progesterone secretion, measured by radioimmunoassay. RESULTS: The immunoreactive NOS was present in human trophoblast cells of normal term placenta and JEG-3 cells (a choriocarcinoma cell line) maintained in culture. Nicotinamide adenine dinucleotide phosphate (NADPH)-dependent diaphorase activity overlapped with the immunostaining of NOS. Specific antibodies against the different isoforms of NOS detected the presence of neuronal-type NOS (nNOS) only. The other two isoforms, i.e., eNOS (endothelial) and iNOS (macrophage specific) were completely absent. The nNOS was localized in cell cytoplasm. In culture, JEG-3 cells normally undergo proliferation and cytotrophoblast cells in primary culture differentiate to form hormone-secreting syncytial cells. Sodium nitroprusside (SNP), a nitric oxide donor, when added to the culture, significantly increased proliferation of JEG-3 cells and inhibited the differentiation of cytotrophoblast cells. The arrest by SNP in the formation of syncytial cells was further evidenced by the low secretion profile of hCG and progesterone. CONCLUSIONS: Our findings suggest for the first time the presence of nNOS in the human trophoblast cells and a previously unrecognized role of NO in trophoblast proliferation and differentiation.

Sequential liquid-liquid extraction graphite furnace atomic absorption spectrometric (GFAAS) and spectrophotometric determination of zirconium(IV) with calixarene hydroxamic acid.

A new calixarene hydroxamic acid, 25,26,27,28-tetrahydroxy-5,11,17,23-tetrakis (N-p-chlorophenyl) calix[4]arene hydroxamic acid (CPCHA) is synthesized and used for the extraction and graphite furnace atomic absorption determination of zirconium(IV). The extract is also determined spectrophotometrically as CPCHA-SCN complex having maximum absorbance at 447 nm with molar absorptivity 9.4x10(3) l mol(-1) cm(-1). The Beer's law obeys in the range of 1.0-9.5 ppm of zirconium. The graphite atomic absorption (GFAAS) increases the sensitivity by about 50 folds. The method is applied to the trace determination of zirconium(IV) in standard samples.

X-ray reflectivity study of semiconductor interfaces.

The results of an X-ray reflectivity study of thick AlAs-AlGaAs and thin Ge-Si-Ge multilayers grown using metal-organic vapour-phase epitaxy and ion-beam sputtering deposition techniques, respectively, are presented. Asymmetry in interfaces is observed in both of these semiconductor multilayers. It is also observed that although the Si-on-Ge interface is sharp, an Si(0.4)Ge(0.6) alloy is formed at the Ge-on-Si interface. In the case of the III-V semiconductor, the AlAs-on-AlGaAs interface shows much greater roughness than that observed in the AlGaAs-on-AlAs interface. For thin multilayers it is demonstrated that the compositional profile as a function of depth can be obtained directly from the X-ray reflectivity data.

Collagenase-IV in human trophoblast invasion and differentiation.

Trophoblast cells are unique with respect to their functions and responsibilities. These cells demonstrate three sequential phenotypes, proliferation and invasion into the endometrium, differentiation to form syncytia and endocrine secretions. Equipped with these properties placental trophoblasts are endowed with a variety of functions, like implantation of the blastocyst to the endometrium, providing nutrition to the developing embryo and also transmitting extraordinary array of signals for the embryonic development. Experimental evidences and logical extrapolation suggest that these functions are precisely controlled by growth factors, cytokines and hormones produced either by the trophoblast themselves or by the utero-placental unit. Any error in this control mechanism has extremely adverse consequences. The cells also synthesize a large number of enzymes, amongst which collagenase type IV secretion is involved in digestion of underlying basement membrane necessary for the process of invasion. Our results implicate the enzyme in the functional differentiation of the trophoblast as well. Inhibitors to this enzyme inhibit trophoblast differentiation as monitored by secretion of hCG and progesterone, the two markers of trophoblastic differentiation. In contrast, BeWo cells, a choriocarcinoma cell line which does not differentiate spontaneously, undergo increased proliferation when challenged with EGF. The results indicate the possibility of invasive and differentiative phenotypes to be coupled. Exact molecular involvements in this coupling process are looked into.

Augmentation of DNA synthesis in placental and fetal tissues in utero by maternal growth hormone treatment.

The influence of maternal exogenous growth hormone treatment on in utero conceptus development was evaluated in the rat. The periods of response and stimulation of DNA synthesis on embryo/fetal and placental tissues were assessed by subcutaneous injections of ovine growth hormone (oGH) preparations during pregnancy days 11-15, autopsied on day 16; and during pregnancy days 11-20 and 16-20, autopsied on day 21. To determine DNA biosynthesis potential, thymidine (methyl-3H) was administered through the jugular vein 14-16 h prior to sacrifice. DNA content and uptake of radiolabeled thymidine into DNA were analyzed for whole embryos on day 16, and for fetal liver, brain and remaining body tissues on day 21 of pregnancy. Placental tissues from oGH-treated mother and controls were also quantified for DNA content and radiolabeled thymidine uptake. oGH treatment produced a significant increase (p < 0.05) in radiolabeled thymidine uptake into DNAs of different fetal organs compared to saline-treated controls matched for weight and litter number during the latter part of gestation (fetal histogenesis period; pregnancy days 16-20). The stimulatory influence of maternal growth hormone treatment on DNA contents and radiolabled thymidine uptake on placental tissues at this period of gestation was also significantly different from that of the controls. Rat conceptus tissues (embryos and placentas) during the organogenesis period of early gestation (days 11-15) appeared to be unresponsive to such treatment. Thus, these results suggest that maternal growth hormone influences conceptus growth during the latter part of gestation and activation of placental functions may be an important aspect of stimulation of cell proliferation in the rat fetus.

Pre-labour rupture of membrane: the histological study of membrane and bacteriological profile.

One hundred two (102) cases of pre-labour rupture of membrane (PROM) were studied and special attention was given to the histological study of the amniotic membrane as well as to the bacteriological study of high vaginal flora, cervical flora and flora of amniotic fluid, in search of probable causes or factors leading to PROM. The incidence was found to be 3.16% in the age group of 20-25 years without any relation to parity; and the duration of gestation was 38 to 40 weeks in most of the cases. The histological study revealed: (a) Focally denuded amniotic epithelium, focally separated amniotic epithelium from chorion layer, lesser density of focal squamoid change of the epithelium and thicker chorion layer probably indicating focal immaturity of the chorio-amnion, (b) lesser thickness of collagen layer, focal hydropic degeneration and mild cellular infiltrate, (c) presence of focal hyaline degeneration and focal calcification of chorio-amnion. Microbial culture revealed: (a) Higher rate of positive culture in high vaginal swab, cervical swab and amniotic fluid showing presence predominantly of Esch coli, Strept haemolyticus, klebseilla species, Staph aureus, Strept non-haemolyticus, proteus species and pseudomonas species against that of positive cultures in the control cases, (b) no anaerobic bacteria from high vaginal swab, cervical swab or from amniotic fluid. It was presumed that focal immaturity of chorio-amnion or focal irregularity in the chorio-amnion at the microscopical level, focal degeneration of collagen superadded with bacterial infection, however mild, could be the factors leading to weakness in the tensile strength of chorio-amnion, again leading to PROM, in the face of stress factors of foetal origin.