Synthesis, characterization, and cytotoxicity studies of nanocellulose extracted from okra (Abelmoschus Esculentus) fiber.

Nanocellulose, especially originating from a natural source, has already shown immense potential to be considered in various fields, namely packaging, papermaking, composites, biomedical engineering, flame retardant, and thermal insulating materials, etc. due to its environmental friendliness and novel functionalities. Thus, a thorough characterization of nanocellulose is a hot research topic of research communities in a view to judge its suitability to be used in a specific area. In this work, a kind of green and environment-friendly nanocellulose was successfully prepared from okra fiber through a series of multi-step chemical treatments, specifically, scouring, alkali treatment, sodium chlorite bleaching, and sulfuric acid hydrolysis. Several characterization techniques were adopted to understand the morphology, structure, thermal behavior, crystallinity, and toxicological effects of prepared nanocellulose. Obtained data revealed the formation of rod-shaped nanocellulose and compared to raw okra fiber, their size distributions were significantly smaller. X-ray diffraction (XRD) patterns displayed that compared to the crystalline region, the amorphous region in raw fiber is notably larger, and in obtained nanocellulose, the crystallinity index increased significantly. Moreover, variations in the Fourier transform infrared spectroscopy (FTIR) peaks depicted the successful removal of amorphous regions, namely, lignin and hemicelluloses from the surface of fiber. Thermostability of synthesized nanocellulose was confirmed by both Differential Scanning Calorimetry (DSC) analysis, and thermogravimetric analysis (TGA). Cytotoxicity assessment showed that the okra fiber-derived nanocellulose exhibited lower to moderate cellular toxicity in a dose-dependent manner where the LD50 value was 60.60 µg/ml.

Micro crystalline cellulose aided surface modification and deposition of green polyelectrolytes for the improved hydrophilicity and flame retardancy of polyamide 66 fabric.

In this work, microcrystalline cellulose (MCC) treated polyamide 66 (PA66) textiles were coated with green and naturally abundant polysaccharides specifically, chitosan (CS) and sodium alginate (SA) together with phytic acid (PA) via layer by layer (LbL) deposition. The prime focus of such treatment was to intensify both the hydrophilic and flame retardant properties of PA66 fabric substrates. Subsequently, the prepared coatings were further subjected to cross-linking modification by dipping them into the barium (Ba) salt solution. Obtained results indicated that the MCC-modified PA66 exhibited a water contact angle (WCA) value of 00 and revealed a drop in peak heat release rate (pHRR) up to 31 % with complete suppression of melt-dripping. Meanwhile, the Ba-ion-induced cross-linking treatment further escalated this reduction up to 36 % by adding enhanced thermal stability, improved char quality along better wash durability of as prepared coatings. In addition, the combined modification of PA66 textiles with MCC and Ba-ion handed a superb enhancement of physical properties like tensile strength by ca. 50 % compared to the pure PA66. Thus, this MCC-assisted surface modification paves the way for a new kind of greener treatment of PA66 textiles in attaining superior hydrophilic and flame retardant properties of the same.

Flame Retardant Coatings from Bio-Derived Chitosan, Sodium Alginate, and Metal Salts for Polyamide 66 Textiles.

Bio-derived polysaccharides, namely, chitosan (CS) and sodium alginate (SA) were considered in a layer-by-layer (LbL) deposition to construct flame retardant coatings onto the polyamide 66 (PA66) fabric surfaces. The as-prepared coatings were further modified in the impregnation process with a number of inorganic salts containing boron, nickel, and iron elements. Obtained results revealed that the simultaneously LbL-assembled and metal salt-treated fabric samples exhibited superior flame retardant performance compared to the only LbL-deposited fabric samples. The limiting oxygen index (LOI) value reached up to 25.5% of the CS-SA-iron salt treated fabric sample and the dripping tendency was completely diminished only for the LbL-metal salt modified fabric samples. Among the treated fabric samples, the CS-SA-iron-salt-modified fabric sample exhibited a maximum reduction in the peak heat release rate by 34% and handed improved and higher quality char residues, indicating a possible condensed phase flame retardant mechanism of this applied finishing. Moreover, metal salt-induced cross-linking could enhance the coating stability and durable finishes against regular home laundering where an iron-salt-treated fabric sample could retain anti-dripping properties even up to 10 laundering cycles. Thus, this pairing of bio-macromolecules (i.e., charring agent) with the metal salts in a hybrid system showed efficacy in improving the fire performance of polyamide textiles via the synergistic involvement between them.

Graphene oxide functionalized biomolecules for improved flame retardancy of Polyamide 66 fabrics with intact physical properties.

A plant derived bio-macromolecule namely lignin (L) and a green phosphorus compound like phytic acid (PA) were functionalized with graphene oxide (GO) and subsequently, used to enhance the flame retardant properties of polyamide 66 (PA66) fabrics in a one pot deposition method. Meanwhile, we also considered pure phytic acid and one more bio-derived charring agent like chitosan (CS) to formulate a series of GO-based flame retardant finishing by altering the applied compounds in the formulation. The applied finishing with a minimum loading % (i.e., less than 10%) rarely altered the physical properties (i.e., color, handle and tensile strength, etc.) of treated textiles while provided enhanced thermal stability and added flame retardancy. Thus, a significant increase in limiting oxygen index (LOI) by 27% was received for the GO-lignin and GO-phytic acid modified fabric sample (i.e., PA66-A), indicating the supremacy of graphene-based compound. Furthermore, a substantial reduction in the peak heat release rate (pHRR) by 25% was also noticed for the fabric sample treated with GO-lignin, chitosan and phytic acid (i.e., PA66-D). Additionally, the as prepared finishing exhibited a considerable level of wash durability as a maximum reduction of pHRR by 17% was retained even after 5 washing cycles.

Chitosan-based flame retardant coatings for polyamide 66 textiles: One-pot deposition versus layer-by-layer assembly.

Chitosan (CS) and phosphorylated chitosan (PCS) were deposited onto the polyamide 66 (PA66) fabric surfaces along with poly-acrylate sodium (PAS) via 'one pot' and layer by layer (LbL) assembly methods in preparing flame retardant coatings. Subsequently, to stabilize the deposited coatings, some of the fabric samples were treated under the UV-irradiation and additionally, a thermal treatment was also carried out for the remaining fabric samples. The LbL assembled fabrics showed a better homogeneity in the coating structure over the one pot deposited fabrics as appeared in scanning electron microscopy (SEM). Nonetheless, the LbL treated fabric sample (i.e., PA66-10BL-UV) with a higher weight gain% exhibited a greater improvement in limiting oxygen index (LOI) (i.e., 23%), and a reduced peak heat release rate (pHRR) (i.e., 25%). Yet more, only the LbL assembled and thermally cross-linked fabric sample could able to retain the flame retardant behavior in the vertical burning test even after 5 washing cycles.

Construction of Bimetallic ZIF-Derived Co-Ni LDHs on the Surfaces of GO or CNTs with a Recyclable Method: Toward Reduced Toxicity of Gaseous Thermal Decomposition Products of Unsaturated Polyester Resin.

This work proposed an idea of recycling in preparing Co-Ni layered double hydroxide (LDH)-derived flame retardants. A novel and feasible method was developed to synthesize CO-Ni LDH-decorated graphene oxide (GO) and carbon nanotubes (CNTs), by sacrificing bimetal zeolitic imidazolate frameworks (ZIFs). Organic ligands that departed from ZIFs were recyclable and can be reused to synthesize ZIFs. ZIFs, as transitional objects, in situ synthesized on the surfaces of GO or CNTs directly suppressed the re-stacking of the carbides and facilitated the preparation of GO@LDHs and CNTs@LDHs. As-prepared hybrids catalytically reduced toxic CO yield during the thermal decomposition of unsaturated polyester resin (UPR). What is more, the release behaviors of aromatic compounds were also suppressed during the pyrolysis process of UPR composites. The addition of GO@LDHs and CNTs@LDHs obviously inhibited the heat release and smoke emission behaviors of the UPR matrix during combustion. Mechanical properties of the UPR matrix also improved by inclusion of the carbides derivatives. This work paved a feasible method to prepare well-dispersed carbides@Co-Ni LDH nanocomposites with a more environmentally friendly method.

Construction of flame retardant coating on polyamide 6.6 via UV grafting of phosphorylated chitosan and sol-gel process of organo-silane.

Phosphorylated chitosan (PCS) was synthesized and grafted onto the surface of polyamide 6.6 (PA 6.6) fabrics via UV-induced grafting polymerization in order to improve the flame retardant properties. Subsequently, PCS grafted PA 6.6 fabrics were modified by (3-aminopropyl) triethoxysilane (APTES) through sol-gel process in order to form a cross-linking coating. The results obtained from the vertical burning test indicated that only the PCS grafted and simultaneously sol-gel treated fabrics could stop the melt dripping. A maximum reduction (30%) in the peak heat release rate was achieved for the PA6.6-PCS-4W-SG fabric sample. The optimal flame retardant effect was achieved for the PA6.6 fabrics treated by PCS and APTES simultaneously, which was attributed to the joint effect of thermal shielding exerted by the silica and char-forming effect derived from PCS.

Childhood lupus nephritis: 12 years of experience from a developing country's perspective.

OBJECTIVE: To assess the long-term outcome of lupus nephritis in children with systemic lupus erythematosus followed up over 12 years at a tertiary care teaching hospital in Eastern India. MATERIAL AND METHODS: This is a retrospective observational study of the clinicopathological presentation, management, and outcome in 46 children with lupus nephritis over a period of 12 years at a tertiary teaching hospital in Eastern India. Mortality was compared between different lupus classes and therapy groups with Kaplan-Meier analysis and log-rank test. RESULTS: The incidence of lupus nephritis was 58.97% [95% confidence interval (CI) 48.06%-59.89%] with the mean age at presentation being 10.2±2.43 years (range 5.5-14.5) years. Majority belonged to class IV (30.43%), followed by class II (26.91%), class III (23.91), and class V (8.70%). Outcome analysis of children with lupus nephritis over 12 years revealed that 24 (52.17%) achieved complete remission of disease activity, 5 attained partial remission, 4 continued to have active disease, 5 developed end-stage renal disease (ESRD), and 8 died. Overall mortality thus observed was 17.39% with septicemia in the background of ESRD being the commonest cause. No significant difference in mortality was observed between different lupus nephritis classes or therapy arm groups. CONCLUSION: The study throws light on various aspects of lupus nephritis and their long-term outcome patterns in children from developing countries such as India.

Blood pressure variation with gestational age and birth weight in Indian newborn.

Prospective observational study was conducted in a tertiary care hospital of India over 8 months to measure blood pressure (BP) in healthy term and preterm neonates using oscillometric method and explore the associations with gestational age and birth weight. Consecutive BP measurements were taken by standard oscillometric method on 1617 neonates on day 4, 7 and 14 of life. Mean birth weight was 2.7 ± 0.46 kg, and mean gestational age was 38.2 ± 2.12 weeks. The mean arterial pressure (MAP) on day 4, 7 and 14 were 59.3 ± 7.33, 63.2 ± 6.55 and 66.4 ± 6.13 mmHg, respectively. Larger and mature newborns had significantly higher BP than those who were smaller and premature. Birth weight more strongly correlated with MAP than gestational age. Predictive equations linking MAP with gestational age and birth weight were deduced, which can be used for judicious fluid inotrope management.

Non-invasive estimation of pulmonary vascular resistance in patients of pulmonary hypertension in congenital heart disease with unobstructed pulmonary flow.

CONTEXT: Pulmonary vascular resistance (PVR) is a critical and essential parameter during the assessment and selection of modality of treatment in patients with congenital heart disease accompanied by pulmonary arterial hypertension. AIM: The present study was planned to evaluate non-invasive echocardiographic parameters to assess pulmonary vascular resistance. SETTINGS AND DESIGN: This prospective observational study included 44 patients admitted in the cardiology and pediatric cardiology ward of our institution for diagnostic or pre-operative catheter based evaluation of pulmonary arterial pressure and PVR. MATERIALS AND METHODS: Detailed echocardiographic evaluation was carried out including tricuspid regurgitation velocity (TRV) and velocity time integral of the right-ventricular outflow tract (VTIRVOT). These parameters were correlated with catheter-based measurements of PVR. RESULTS: The TRV/VTIRVOT ratio correlated well with PVR measured at catheterization (PVRcath) (r = 0.896, 95% confidence interval [CI] 0.816 to 0.9423, P < 0.001). Using the Bland-Altman analysis, PVR measurements derived from Doppler data showed satisfactory limits of agreement with catheterization estimated PVR. For a PVR of 6 Wood units (WU), a TRV/VTIRVOT value of 0.14 provided a sensitivity of 96.67% and a specificity of 92.86% (area under the curve 0.963, 95% confidence interval 0.858 to 0.997) and for PVR of 8 WU a TRV/VTIRVOT value of 0.17 provided a sensitivity of 79.17% and a specificity of 95% (area under the curve 0. 0.923, 95% confidence interval 0.801 to 0.982). CONCLUSIONS: Doppler-derived ratio of TRV/VTIRVOT is a simple, non-invasive index, which can be used to estimate PVR.

Unique neurological manifestations of dengue virus in pediatric population: a case series.

Dengue infection is endemic in developing countries posing a major public health problem. Clinical manifestations form a broad spectrum and include uncomplicated dengue fever, dengue hemorrhagic fever and dengue shock syndrome. We report three confirmed cases of dengue infection in pediatric population with central nervous system involvement with certain unreported manifestations resulting in diagnostic dilemma. Increasing evidence of neurotropism by dengue virus emphasizes that clinician be aware of such association and consider dengue infection in cases of febrile encephalitis and myelitis in endemic areas. Early diagnosis and appropriate supportive cars can reverse this potentially fatal disease.

Food supplementation as an incentive to improve pre-antiretroviral therapy clinic adherence in HIV-positive children--experience from eastern India.

OBJECTIVE: To evaluate the importance of food supplementation as incentive in improving preantiretroviral therapy (pre-ART) adherence, and second its impact on health of HIV-infected children by a clinic-based observational study. METHODS: HIV-seropositive children aged between 2 and 12 years were followed-up sequentially for 2 years without and with food supplementation, respectively, with monitoring of disease parameters. The outcome morbidity parameters were compared and correlated. RESULT: Study showed significant improvement in clinic adherence (r = 0.165, p = 0.027) along with increased mean clinic visit (6.65 ± 1.43 vs. 8.01 ± 1.52, p = 0.000) and mean CD4 count (p = 0.028) with incentive. Provision of incentive correlated well (Pearson's r = 0.345) with number of visits which in turn had strong correlation with weight gain (r = 0.548), episodes of AIDS-defining illnesses (r = -0.412), hospitalization (r = -0.279). CONCLUSION: Food incentive could enhance pre-ART phase clinic adherence that decreases disease-related morbidities, setting the stage for improved treatment and care of seropositive children in future.