Histopathological Correlation in Different Types of Leprosy in a Tertiary Health Care Centre

Hansen’s disease or Leprosy, is a chronic infectious disease that is contagious and has a slow evolution. It affects mainly skin and schwann cells in the peripheral nerves and causes peripheral neuropathy which contributes to the permanent functional impairments [1]. It is caused by a rod shaped,acid fast staining bacteria known as Mycobacterium Leprae which has parallel sides, round ends and a characteristic bundle of cigar appearance due to the presence of a glial substance which is a surface lipid that makes the bacilli to be arranged side by side in parallel arrays [2]. It has a distinctive empathy towards the peripheral nerves where it establishes originally therefore it is the site where the pathological processes start mainly with the principal target being Schwann cell [3,4]. Amidst the communicable diseases, Leprosy is the most common cause of physical disabilities which is permanent. When the bacterium enters a person with good cell-mediated immunity against it, it gets destroyed. If there is a slight impairment in the cell-mediated immunity against it, some bacilli will multiply and a lesion develops. Depending upon the immune status of a host, it expresses itself in different clinico-histopathological forms [5]. Ridley and Jopling suggested a five-group classification of leprosy known as immunological classification based upon the immunological status of the patient as (a) tuberculoid (TT), (b) borderline tuberculoid (BT), (c) mid-borderline (BB), (d) borderline lepromatous (BL) and (e) lepromatous (LL) [6]. Bacteriological, immunological, clinical and histopathological features exhibit continuous but slow changes from one pole to another pole. The main disadvantage of this classification is that there is no specific position for pure neuritic as well as indeterminate leprosy in the spectrum [7].

A two-dimensional calcium (II) coordination polymer constructed from 2,2′-[terephthaloylbis(azanediyl)]diacetate: synthesis, structure and properties

A new two-dimensional (2D) coordination polymer, namely, poly[[diaqua-[μ4-2,2′-[terephthaloylbis(azanediyl)]diacetato]calcium(II)] monohydrate], {[Ca(C12H10N2O6)(H2O)2]·H2O} n , (I), has been synthesized by the reaction of CaCl2 with 2,2′-[terephthaloylbis(azanediyl)]diacetic acid (H2 L). The title compound was structurally characterized by single-crystal X-ray diffraction analysis, elemental analysis and IR spectroscopy. In the crystal structure of (I), each CaII cation binds to six carboxylate groups from four symmetry-related L 2− dianions. The hexadentate L 2− ligand links four symmetry-related calcium cations into a 2D layer-like structure, which can be simplified as a uninodal SP 2-periodic (3,6)III net with the point symbol (43·63). In the lattice, all layers pack in parallel arrays through weak interlayer hydrogen bonding and π–π interactions. The thermal stability and photoluminescence properties of (I) have been investigated. Thermogravimetric analysis reveals the different thermal stabilities of the two coordinated water molecules due to their different hydrogen-bonding interactions. The title coordination polymer exhibits an excitation-wavelength-dependent fluorescence in the solid state.

Dynamics and Bifurcations in Networks Designed for Frequency Conversion

This article reviews recent progress in signal frequency up-conversion and down-conversion, both theory and experiments with network implementations. The fundamental idea is to exploit the inherent symmetry of networks to produce collective behavior in which certain oscillators tend to oscillate at different frequencies. This concept is significantly different from other techniques, e.g. master-slave systems, in the sense that the collective behavior arises naturally from the mutual interactions of the individual units, and without any external forcing. In this manuscript, we present a comprehensive review of the basic ideas, methods, and experiments of the symmetry-based phenomenon of frequency conversion. In addition, we present a review of a device implementation of a broad spectrum analyzer, which motivated the development of systematic methods to up- and down-convert frequencies of oscillations. This device is made up of large parallel arrays of analog nonlinear oscillators with the ability to receive complex signals containing multiple frequencies and instantaneously lock-on or respond to a received signal in a few oscillation cycles.

Metal Sources in the Proterozoic Vazante-Paracatu Sediment-Hosted Zn District, Brazil: Constraints from Pb Isotope Compositions of Meta-Siliciclastic Units

ABSTRACT Different types of sediment-hosted whole-rock Pb isotope (206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb) compositions were determined from phyllites, carbonaceous phyllites (>1% TOC), and meta-litharenites belonging to the Serra do Garrote Formation, which is part of the Proterozoic Vazante Group, Brazil. Results were integrated with lithogeochemistry in order to identify the Pb isotopic signature of Zn enrichment (up to 0.24 wt.% Zn) associated with meta-siliciclastic-hosted sulfide mineralization that formed prior to the Brasiliano Orogeny (850 to 550 Ma) in order to (1) understand the nature of siliciclastic sediment sources, (2) identify possible metal sources in pre-orogenic meta-siliciclastic-hosted Zn mineralization, and (3) evaluate the genetic links between the Zn enrichment in the relatively reduced phyllite package, and different styles of syn-orogenic Zn ± Pb mineralization (hypogene Zn-silicate and Zn-Pb sulfide) in overlying dolomitic carbonates throughout the Vazante-Paracatu Zn District, Brazil. The whole-rock 206Pb/204Pb and 207Pb/204Pb isotope ratios of meta-siliciclastic rocks plot as positively sloping, sub-parallel arrays with radiogenic, upper continental crust compositions, which could represent a detrital contribution from at least two upper continental crust sources. However, the 206Pb/204Pb versus 207Pb/204Pb isotope system does not distinguish between Zn-enriched samples and un-mineralized samples. In the whole-rock 206Pb/204Pb–208Pb/204Pb plot, Zn-enriched samples form a flat trend of lower 208Pb/204Pb values (38.3 to 39.5) compared to the Zn-poor ones that follow common upper crustal trends. Zinc-enriched samples have low whole-rock Th/U values (<4) and higher whole-rock U concentrations compared to unmineralized samples. These support the hypothesis that U (± Pb) was added by pre-orogenic metalliferous fluids, which were in turn derived from underlying Paleoproterozoic and Archean basement rocks. Due to U addition, the original whole-rock thorogenic and uranogenic Pb isotope systems were decoupled in mineralized samples. Pre-orogenic metalliferous fluids have similar present-day first-order characteristics, including: (1) relatively high U/Pb and (2) low Th/U values, when compared to galena in the major carbonate-hosted Zn ± Pb deposits (Vazante, Morro Agudo, Ambrosia, Fagundes) in the Vazante Group. These results support the hypothesis that Zn-rich layers and veins in mineralized carbonaceous phyllites could be linked to the same origins as carbonate-hosted mineral deposits throughout the Vazante Basin, but further data are warranted. We suggest that the tectonic evolution of the Vazante Basin saw multiple phases of Zn-rich mineralization over protracted time periods from around 1200 to 550 Ma.

Wnt signaling establishes the microtubule polarity in neurons through regulation of Kinesin-13

Neuronal polarization is facilitated by the formation of axons with parallel arrays of plus-end-out and dendrites with the nonuniform orientation of microtubules. In C. elegans, the posterior lateral microtubule (PLM) neuron is bipolar with its two processes growing along the anterior–posterior axis under the guidance of Wnt signaling. Here we found that loss of the Kinesin-13 family microtubule-depolymerizing enzyme KLP-7 led to the ectopic extension of axon-like processes from the PLM cell body. Live imaging of the microtubules and axonal transport revealed mixed polarity of the microtubules in the short posterior process, which is dependent on both KLP-7 and the minus-end binding protein PTRN-1. KLP-7 is positively regulated in the posterior process by planar cell polarity components of Wnt involving rho-1/rock to induce mixed polarity of microtubules, whereas it is negatively regulated in the anterior process by the unc-73/ced-10 cascade to establish a uniform microtubule polarity. Our work elucidates how evolutionarily conserved Wnt signaling establishes the microtubule polarity in neurons through Kinesin-13.

Petrogenesis of Archaean granites in the Barberton region of South Africa as a guide to early crustal evolution

ABSTRACT The Barberton region of South Africa is characterized by a broad variety of granite types that range in age from ca. 3.5 Ga to 2.7 Ga and reflect the processes involved in the formation of Archaean continental crust on the Kaapvaal Craton. These granites are subdivided into three groups, as follows: A tonalite-trondhjemite-granodiorite (TTG) suite diapirically emplaced at 3 450 Ma and 3 250 Ma into pre-existing metamorphosed greenstone belt material. TTG melts were derived from melting amphibolite in the lower crust, with individual plutons being emplaced at various crustal levels. The dome-and-keel geometry that characterizes the TTG-greenstone dominated crust at this time is inconsistent with a plate tectonic domain and reworking was likely controlled by gravity inversion or ‘sagduction’; Regionally extensive potassic batholiths (the GMS suite) were emplaced at 3 110 Ma during a period of crustal thickening and melting of a TTG-dominated lower crust. Subsequent to emplacement of the voluminous GMS granites, the thickened continental crust had stabilized sufficiently for large sedimentary basins to form; Late granite plutons were emplaced along two distinct linear and sub-parallel arrays close to what might have been the edge of a Kaapvaal continent at 2 800 to 2 700 Ma. They are subdivided into high-Ca and low-Ca granites that resemble the I- and S-type granites of younger orogenic episodes. The high-Ca granites are consistent with derivation from older granitoids in the lower crust, whereas the low-Ca granites may have been derived by melting metasedimentary precursors in the lower-mid crust. Granites with similar characteristics are associated with a subduction zone in younger terranes, although the recognition of such a feature at Barberton remains unclear. The petrogenesis of granites in the Barberton region between 3.5 Ga and 2.7 Ga provides a record of the processes of Archaean crustal evolution and contributes to discussions related to the onset of plate tectonics.

Use of Stacked Layers of Electrospun L-Lactide/Glycolide Co-Polymer Fibers for Rapid Construction of Skin Sheets

This paper describes a novel method for the rapid construction of skin, using multiple layers of aligned electrospun fibers as starting scaffolds. Scaffolds were spun from biodegradable L-lactide/glycolide (molar ratio 10:90) with predominantly parallel arrays of fibers attached peripherally to thin 304 stainless steel layer frames. Each layer frame was held between two thicker support frames. Human skin cells were seeded onto multiple (three–nine) scaffolds. Dermal fibroblasts were seeded on both sides of each scaffold except for one on which keratinocytes were seeded on one side only. Following 48 h of culture, the scaffolds and layer frames were unmounted from their support frames, stacked, with keratinocytes uppermost, and securely held in place by upper and lower support frames to instantly form a multilayered “dermis” and a nascent epidermis. The stack was cultured for a further 5 days during which time the cells proliferated and then adhered to form, in association with the spun fibers, a mechanically coherent tissue. Fibroblasts preferentially elongated in the dominant fiber direction and a two-dimensional weave of alternating fiber and cell alignments could be constructed by selected placement of the layer frames during stacking. Histology of the 7-day tissue stacks showed the organized layers of fibroblasts and keratinocytes immuno-positive for keratin. Electron microscopy showed attachment of fibroblasts to the lactide/glycolide fibers and small-diameter collagen fibers in the extracellular space. This novel approach could be used to engineer a range of tissues for grafting where rapid construction of tissues with aligned or woven layers would be beneficial.