Structural characterization of Saudi Arabian heavy crude oil by n.m.r. spectroscopy

Saudi Arabian heavy crude oil was separated into six fractions, including five distillate fractions (<93, 93–204, 204–260, 260–343 and 343–454 °C) and a >454 °C distillation residue. Each fraction was analysed by ¹H and ¹³C n.m.r. spectroscopy, and combined gained information from these analyses provided reliable average structural parameters. These included estimation of aliphatic and aromatic content, average paraffinic chain length, and estimation of hydrogen, methyl and alkyl bearing aromatic carbons for each of the six fractions. The extent of branching in paraffinic chains and amount of aromatic bridgehead carbons were also calculated.     

Light Fastness and Shade Variability of Tannin Colorant Dyed Wool with the Effect of Mordanting Methods

Mordanting methods effect on color characteristics and fastness properties, particularly light fastness were evaluated in this study. Effect of metal mordants and their combinations on wool dyeing with Terminalia chebula natural dye were investigated and correlation between dye structures, effect of metal mordant and mordanting methods were established. Results reveal that T. chebula can be used as yellow dye with or without metal mordants to get a variable range of shades on wool with good color strength and fastness properties, and appreciable shade variations with mordanting methods observed. Color performances of dyed substrate indicated substantial improvement in depth of shades and color fastness in case of mordanted samples. Pre-mordanting with tin and post-mordanting with alum proved to be most effective for increasing K/S values of the dyed substrate under the optimum dyeing conditions.     

Enhanced photoelectrochemical water splitting using zinc selenide/graphitic carbon nitride type-II heterojunction interface

The objective of this research is to construct a type-II heterojunction interface for effective photoelectrochemical (PEC) water splitting for hydrogen generation. A series of ZnSe/g-C₃N₄ heterojunctions is prepared by ultrasonication procedure and tested for PEC water splitting for the first time. The successful formation of ZnSe/g-C₃N₄ is confirmed by phase, morphological and optical analysis. Linear sweep voltammetry of 0.05 ZG (0.05% ZnSe/g-C₃N₄) showed a six-fold higher photocurrent density of 500 μA than g-C₃N₄. These results are supported by the Tafel slopes and PL (photoluminescence spectroscopy) studies by showing the smallest slope and lesser electron-hole recombination for 0.05 ZG. Increased lifetime of 107 ms and a higher donor density of 3.6 × 10¹⁹ cm^?3 for 0.05 ZG is observed. The smallest semicircle for 0.05 ZG in EIS implies the least charge transfer resistance among the prepared heterojunctions. All the results comply with each other showing the successful formation of type-II heterojunction for enhanced PEC water splitting.     

Surface molecular imprinting of nylon fibers for chiral recognition of d‐phenyllactic acid

In the current work, synthetic polyamide nylon fibers were modified via the strategy of surface molecular imprinting to develop enantio‐selective adsorbent fabrics for chiral recognition of d ‐phenyllactic acid (d‐ PhLA). The nylon fibers were first modified by grafting of polyacrylamide and then the incorporated amide groups were converted into functional amino groups via treatment with NaOCl (Hofmann degradation). The amino‐functionalized nylon fibers (Ny‐NH₂) were interacted with the targeted d‐ PhLA enantiomer before crosslinking the amino‐containing grafted chains with glutaraldehyde crosslinker followed by leashing the template d‐ PhLA out of the formed surface polymeric matrix by lowering the pH to 1 to finally produce the desired enantio‐selective adsorbent fibers DP‐Ny. Different instrumental methods such as elemental analysis, Fourier transform infrared spectroscopy, XRD and TGA were employed to examine all the synthetic procedures. SEM was also utilized to observe the morphological appearances of both native and modified nylon fibers. Moreover, the optimum extraction of d‐ PhLA was found to occur at pH 7. Isotherm studies of the prepared DP‐Ny fibers obeyed the common Langmuir linear equation with q_m values 130 ± 2 and 75 ± 1 mg g^?1 in the case of d‐ PhLA and l‐ PhLA, respectively. Furthermore, the enantiomeric resolution of (±)‐PhLA racemate was successfully carried out by a column technique with enantiomeric excess reaching approximately 78%. © 2019 Society of Chemical Industry     

Molecular Pathogenesis of Neuromyelitis Optica

Neuromyelitis optica (NMO) is a rare autoimmune disorder, distinct from multiple sclerosis, causing inflammatory lesions in the optic nerves and spinal cord. An autoantibody (NMO IgG) against aquaporin-4 (AQP4), a water channel expressed on astrocytes is thought to be causative. Peripheral production of the antibody is triggered by an unknown process in genetically susceptible individuals. Anti-AQP4 antibody enters the central nervous system (CNS) when the blood brain barrier is made permeable and has high affinity for orthogonal array particles of AQP4. Like other autoimmune diseases, Th17 cells and their effector cytokines (such as interleukin 6) have been implicated in pathogenesis. AQP4 expressing peripheral organs are not affected by NMO IgG, but the antibody causes extensive astrocytic loss in specific regions of the CNS through complement mediated cytotoxicity. Demyelination occurs during the inflammatory process and is probably secondary to oligodendrocyte apoptosis subsequent to loss of trophic support from astrocytes. Ultimately, extensive axonal injury leads to severe disability. Despite rapid advances in the understanding of NMO pathogenesis, unanswered questions remain, particularly with regards to disease mechanisms in NMO IgG seronegative cases. Increasing knowledge of the molecular pathology is leading to improved treatment strategies.     

Adsorption of bromo-phenol blue from an aqueous solution onto thermally modified granular charcoal

The adsorption phenomenon of bromo-phenol blue onto pristine and thermally evacuated granular charcoal (GC) was studied via a batch technique at 25 °C. The effect of evacuation temperature on the GC surface and pore structure (e.g. pore volume and diameter) was studied by Fourier transform infrared spectroscopy (FT-IR), point of zero charge (PZC), proximate analysis, Brunauer, Emmett and Teller (BET) method and field emission scanning electron microscopy (FE-SEM). The FT-IR spectra of the samples after evacuation showed considerable decrease in the acidic functional groups. PZC showed that the surface of the evacuated charcoal became basic as the evacuation temperature was increased from 300 to 800 °C. Volatile matter decreased while ash and fixed carbon contents increased during evacuation, which led to an increase in the micro-pore volume from 0.25 to 0.42 cm³ g⁻¹, meso-pore volume from 0.04 to 0.13 cm³ g⁻¹, pore diameter from 5.01 to 6.21 nm, and specific surface from 150.32 to 254.70 m² g⁻¹. Adsorption of the bromo-phenol blue onto charcoal, increased as the evacuation temperature was increased from 300 to 800 °C. The interaction of bromo-phenol blue with charcoal was proposed to have occurred via hydrogen bonding. The adsorption data fitted well with the Langmuir equation, which indicated that the monolayer adsorption has occurred at specific sites within the adsorbent.     

Will the Overseas Expansion of Facebook Succeed?

Social networking sites (SNSs) are becoming mainstream and are spreading worldwide. Here, the authors review Facebook and Orkut, two major SNSs, and analyze a recent survey conducted among Indian and Pakistani Orkut users. They aim to investigate Orkut users' experiences with Facebook, which has a stronghold in the US and is expanding globally to compete with Orkut. The survey indicates that the conservative and anticommercial Indian and Pakistani cultures might be a major challenge for Facebook in competing with Orkut in these societies.     

Effect of Binary and Ternary Combination of Metal Salt Mordants on Dyeing and Fastness Properties of Natural Protein Fibre with Juglans regia L. Dye

The present article focuses on the effect of different combinations of metal mordants on color characteristics and fastness properties of natural dye extracted from Juglan regia L bark powder. The influence of different types of mordant combinations such as alum + ferrous sulphate, alum + stannous chloride, ferrous sulphate + stannous chloride, and alum + ferrous sulphate + stannous chloride on color parameters has been investigated in terms of CIELab (L*, a*, b*, c*, and h°) and K/S values. The fastness properties with respect to light, washing, and crocking of developed shades were determined according to ISO and AATCC test methods. Based on the experimental results, it has been found that 96 shades with novel and fashionable hues were produced by the use of these metal salt combinations. It was also found that all mordanted samples had satisfactory light and wash fastness ratings. Dry rub fastness was found relatively better than wet rub fastness.     

Exploiting the potential of polyphenolic biomordants in environmentally friendly coloration of wool with natural dye from Butea monosperma flower extract

Coloration of textiles with natural dyes involves huge consumption of chemicals; mainly, metal salt mordants, which pose serious environmental challenges. To mitigate this pollution, more and more environmentally friendly, biodegradable, biocompatible and renewable products should be popularized in dyeing industry. This paper proposes a sustainable and metal salt-free dyeing of wool samples by employing natural mordants extracted from pomegranate peel (Punica granatum L), gallnut (Quercus infectoria L) and catechu (Acacia catechu). The color parameters of dyed wool samples were greatly found to be dependent on the chemical compounds present in respective biomordants and their interaction ability with the functional groups of wool and the dye molecules. The investigated biomordants exhibit different interactions with coloring compounds of Butea monosperma (palas) dye resulting in deep brown, olive green, dark brown, cinnamon, burgundy, and yellowish hues on wool. All the biomordants selected in this study improved dye performance and resulted in a broad beautiful spectrum of colors with acceptable fastness properties. The results encourage the search and exploitation of new plant species as a source of biomordants to replace metallic and toxic mordants currently used in textile industry.