The major tradition in Bengal boat-building carpentry is that of edge to edge (carvel) joinery in planks to shape the hull. The patia, a sea-going fishing craft of the south Medinipur area of West ...Bengal, is rooted in a north Orissa tradition and represents a departure from this typology. Three types of plank joinery can be identified in specific sections of the hull - reverse clinker, carvel and clinker. Unlike the other West Bengal fishing boars, which are maneuvered essentially in riverine waters, the patia is used in coastal fishing. This article follows the course of the boat building procedure from initiation of construction to completion. The angle of vision is basically ethno-historical. Apart from technical processes and procedures, corresponding rituals and belief systems are also described. The text is essentially based on field generated data as the subject has been little explored from this perspective in archival and published sources.
The effect of stannic oxide (SnO2) nanoparticles on the electrical conductivity relaxation and distribution of relaxation times within the 4-Dodecylbenzenesulfonic acid (DBSA) doped polyaniline ...(Pani) was investigated using electrical impedance spectroscopy. A temperature dependent Kohlrausch–Williams–Watts (KWW) type temporal relaxation function in the time domain was generated from the analysis of the frequency dependence of the dielectric modulus (imaginary component). The thermal evolution of the characteristics parameters of the KWW function was evaluated and using these parameters the temperature dependent average conductivity relaxation time and associated macroscopic conductivity of different samples were estimated. The study revealed that SnO2 nanoparticles within the polyaniline matrix induced faster relaxation of charge carriers that essentially enhanced the conductivity of the nanocomposite. The observed phenomena were well supported by the observed improvement of the localization length of the charge carriers within the nanocomposite.
•Dodecylbenzenesulfonic acid doped polyaniline and its SnO2 incorporated nanocomposite were synthesized.•Temperature dependent imaginary part of the electrical modulus spectra were analyzed in frequency domain.•Relaxation time distribution function was created.•KWW type temporal relaxation function was generated to analyze the thermal evolution of the conductivity relaxation time and DC conductivity.
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•Uniformly dispersed Ag nanoparticles are grown within the PVDF and PVDF-HFP matrix to form nanocomposites.•Non-Isothermal crystallization kinetics of the nanocomposites has been ...studied.•Different models are employed to analyze the crystallization kinetics.•Different nucleation and growth parameters are evaluated.•The formation of polymorphism has been described in support of FT-IR spectra.
Silver nano-particle embedded polyvinylidene fluoride (PVDF) and poly (vinylidene fluoride– hexafluoropropylene) (PVDF-HFP) was prepared by in-situ chemical reaction. The formation of silver nanoparticles was confirmed by UV–vis spectroscopy and HR-TEM image analysis. The weight percentage of silver nano-particle was estimated by thermogravimetric analysis (TGA). Nonisothermal melt-crystallization kinetics and nucleation of molten polymers were analyzed by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Different parameters coming from the DSC data recommended that silver nano-particle enhanced the molecular chain mobility of molten PVDF during its crystallization but for PVDF-HFP it hindered the chain mobility. The values of effective activation energies, calculated by the differential isoconventional method supported the results. Fourier transform infrared spectroscopy (FT-IR) and melting thermograms of different samples concluded that silver nano-particles helped to form polar β- phase of molten PVDF during crystallization but it was ineffective for PVDF-HFP.
Neuropsychiatric disorders classically lack defining brain pathologies, but recent work has demonstrated dysregulation at the molecular level, characterized by transcriptomic and epigenetic ...alterations
. In autism spectrum disorder (ASD), this molecular pathology involves the upregulation of microglial, astrocyte and neural-immune genes, the downregulation of synaptic genes, and attenuation of gene-expression gradients in cortex
. However, whether these changes are limited to cortical association regions or are more widespread remains unknown. To address this issue, we performed RNA-sequencing analysis of 725 brain samples spanning 11 cortical areas from 112 post-mortem samples from individuals with ASD and neurotypical controls. We find widespread transcriptomic changes across the cortex in ASD, exhibiting an anterior-to-posterior gradient, with the greatest differences in primary visual cortex, coincident with an attenuation of the typical transcriptomic differences between cortical regions. Single-nucleus RNA-sequencing and methylation profiling demonstrate that this robust molecular signature reflects changes in cell-type-specific gene expression, particularly affecting excitatory neurons and glia. Both rare and common ASD-associated genetic variation converge within a downregulated co-expression module involving synaptic signalling, and common variation alone is enriched within a module of upregulated protein chaperone genes. These results highlight widespread molecular changes across the cerebral cortex in ASD, extending beyond association cortex to broadly involve primary sensory regions.
To determine whether there are identifiable, reproducible findings in the trabecular meshwork (TM) of patients with primary open-angle glaucoma (POAG) who underwent Kahook Dual Blade (KDB) goniotomy.
...Noncomparative retrospective case series.
Tertiary academic referral center, Veterans Affairs Medical Center. Thirteen patients (14 eyes) with POAG (100%) were treated with KDB goniotomy from May to December 2017. Isolated TM tissue was collected from 9 patients (10 eyes) and submitted for histologic analysis. Hematoxylin-eosin, periodic acid–Schiff, and elastin Van Gieson stains were completed, in addition to immunohistochemistry for collagen IV.
Mean age of patients was 74.2 ± 6.7 years. Trabecular beams were identified in all 10 specimens, although distorted in 4 samples, of which 3 had a history of laser trabeculoplasty. Collagen IV staining was present in 10 of 10 samples, coating the trabecular beams. Elastin was present in 8 of 10 samples along the trabecular beams. Intraocular pressure and number of glaucoma medications decreased significantly in all cases postoperatively (P < .0001, P = .035, respectively).
This pilot study demonstrates that tissue obtained during KDB goniotomy has a high yield of containing TM compared to reported yield of TM in specimens collected from traditional ab externo trabeculectomy (71% vs 20%, respectively). These goniotomy specimens possess sufficient anatomic preservation to be studied histologically. Trabecular meshwork obtained with this procedure may provide a novel modality to study TM dysfunction in open-angle glaucomas.
•A model for binary alloy dendrite growth with thermal anisotropy is developed.•Anisotropy departure source term is used to specify deviation from isotropic model.•Significant effect of thermal ...anisotropy on grain growth and morphology is seen.
A numerical model to study the effect of thermal anisotropy on binary alloy dendrite growth is presented. The model is based on the volume averaged enthalpy method with explicit surface tension anisotropy for crystal orientation. Thermal anisotropy is incorporated using anisotropic thermal conductivity in the energy equation. This is done by splitting the anisotropic conductivity into two parts, equivalent isotropic conductivity and anisotropic departure source term, enabling the use of a conventional isotropic solver to model anisotropic heat transfer. The proposed model is applied to study the effect of thermal anisotropy ratio on tip velocity, aspect ratio and equivalent radius of an equiaxed grain growing in an undercooled binary alloy melt. It is found that the thermal energy stored in the grain during solidification plays an important role in interface evolution, and thus anisotropic conductivity in the solid affects the grain morphology. There is a consistent increase in the aspect ratio of grains with increase in thermal anisotropy ratio, although the grain volume remains almost invariant. Due to unequal growth rates of the perpendicular arms, severe distortion of the solid crystal is seen at higher thermal anisotropy ratios. The model is further extended to study the growth of multiple dendrites in order to simulate microstructure evolution with thermal anisotropy. It is observed that thermal anisotropy significantly affects the grain morphology at low grain density but has a smaller influence at high grain density as compared to other governing factors such as solute transport.
In this study, polyaniline (PAni)/poly(vinylidene fluoride) (PVDF) blends of different compositions were prepared by in situ chemical polymerization of aniline in a mixture of PVDF and ...dimethylformamide (DMF). Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetry (TG) and differential scanning calorimetry (DSC) were utilized to understand the effect of different amounts of in situ PAni loading on the crystalline structure, phase transition and dynamic melt-crystallization kinetics of PVDF. The images for morphology obtained using scanning electron microscopy and polarizing optical microscopy also provided the confirming evidences. FT-IR studies revealed that the transition of the crystalline structure (from β- to α-phase) of pure PVDF during recrystallization is hindered by the incorporation of PAni within the matrix. The dynamic crystallization kinetics data were analysed with different macroscopic models to describe the polymer crystallization, and the parameters obtained from the analyses were correlated with the structural evidence to verify their applicability for the systems under investigation. Values for the effective activation energy ( E X ) of the crystallization process of PVDF and its blends were calculated by the differential isoconversional methods of Friedman. It was observed that, although PAni acted as an effective nucleating agent to induce a great number of heterogeneous nuclei within the blends, it actually delayed the overall crystallization process. The increased values of the crystal growth parameters obtained from the analysis of the temperature-dependent E X by the modified Hoffman–Lauritzen theory also support the above mentioned interpretations.
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