Impact of regulatory capital on bank interest margins: Moderating role of default risk.

The recent pandemic and aftermath debate regarding bank interest margins deserve special attention and have become policy dialogue in emerging economies. However, the previous literature's findings were largely inconclusive and ignored influential variables such as the impact of default risk on bank interest margins. Using a two-step system GMM estimation considering 32 Bangladeshi commercial banks from 2000 to 2022, we produce robust evidence that higher regulatory capital restrictions reduce the bank interest margin, while increased default risk induces the bank interest margin. The impact intensity during the COVID pandemic is higher than in the pre-COVID period. Moreover, we find the synergy effect of regulatory capital and default risk assists in reducing the bank interest margin. Bank margin persistently fell during the capital market crash period, whereas it rose in the financial crisis period. We cast several robustness tests to confirm our main findings. These findings could generate important implications for bank stakeholders and policymakers.

Sustainable leather tanning: Enhanced properties and pollution reduction through crude protease enzyme treatment.

In this study, proteolytic bacteria, particularly Pseudomonas aeruginosa strain SM4 (OQ349573), were isolated from tannery solid waste dumping yard soil and employed to produce extracellular protease enzymes. The bacteria exhibited optimal growth after 30 h of incubation at 37 °C and pH 7. Under conditions of 55 °C, pH 8, and a substrate concentration of 2 %, the crude enzyme displayed its highest activity at 105 UmL-1. Notably, the produced crude enzyme showed no discernible inhibitory effects on detergents, metal salts, or organic solvents. Application of the crude protease at concentrations of 3 % and 2 % in chrome tanning of goatskins (GS) and cowhides (CH), respectively, yielded significant reductions of 35 % and 30 % in chromium and other post-tanning chemicals compared to conventional processes. Despite the 30 to 35 % reduction in tanning and post-tanning chemicals, the uptake of chrome and associated chemicals by crust leather was higher than observed in conventional processes. Chromium content analysis of the effluent revealed an 81 % reduction during piloting in real industrial operations, accompanied by reductions of about 46 % in BOD and COD pollution loads. The finished leather obtained from the enzymatic process exhibited superior mechanical properties, including higher tensile strengths (210 and 195 kg cm-2), stitch tear (92 and 165 kg cm-1), grain crack load (28 and 32 kg), and distension (73 and 62 mm) for GS and CH, respectively, surpassing or closely aligning with standard values and those obtained in conventional processes.

Chitosan-Stabilized CuO Nanostructure-Functionalized UV-Crosslinked PVA/Chitosan Electrospun Membrane as Enhanced Wound Dressing.

Electrospun nanofibrous membranes are of great interest for tissue engineering, active material delivery, and wound dressing. These nanofibers possess unique three-dimensional (3D) interconnected porous structures that result in a higher surface-area-to-volume ratio and porosity. This study was carried out to prepare nanofibrous membranes by electrospinning a blend of PVA/chitosan polymeric solution functionalized with different ratios of copper oxide. Chitosan-stabilized CuO nanoparticles (CH-CuO NPs) were biosynthesized successfully utilizing chitosan as the capping and reducing agent. XRD analysis confirmed the monoclinic structure of CH-CuO NPs. In addition, the electrospun nanofibrous membranes were UV-crosslinked for a definite time. The membranes containing CH-CuO NPs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-vis) spectrophotometry, and dynamic light scattering (DLS). SEM results showed the nanosize of the fiber diameter in the range of 147-207 nm. The FTIR spectroscopy results indicated the successful incorporation of CH-CuO NPs into the PVA/chitosan nanofibrous membranes. DSC analysis proved the enhanced thermal stability of the nanofibrous membranes due to UV-crosslinking. Swelling and degradation tests were carried out to ensure membrane stability. Greater antimicrobial activity was observed in the nanoparticle-loaded membrane. An in vitro release study of Cu2+ ions from the membrane was carried out for 24 h. The cytotoxicity of CH-CuO NP-incorporated membranes was investigated to estimate the safe dose of nanoparticles. An in vivo test using the CH-CuO NP-loaded PVA/chitosan membrane was conducted on a mice model, in which wound healing occurred in approximately 12 days. These results confirmed that the biocompatible, nontoxic nanofibrous membranes are ideal for wound-dressing applications.

A green strategy for collagen extraction from tannery raw trimmings using papain enzyme: Process optimization by MW-TOPSIS for enhanced yield.

The leather industry poses a significant environmental problem through the extensive discharge of trimming waste, primarily composed of skin matrix rich in proteins. Developing a green approach for utilizing this waste can contribute to the sustainable recovery of proteins, transforming them into valuable bioresources. This study introduces an environmentally friendly and economically viable approach to extract collagen from tannery raw trimming waste using papain enzyme-derived from papaya leaves. The research involved extensive assessments and trials to optimize the enzymatic hydrolysis process. The highest collagen recovery was achieved by hydrolyzing 5 % (w/v) delimed powder with 4 % (w/v) crude papain enzyme from papaya leaf powder, maintaining it at 60 °C for 6 h and at pH 5. Collagen extraction from raw trimming waste using acetic acid was also performed, with the optimized papain enzyme-based hydrolysis process resulting in approximately 91 % yield, while conventional acetic acid method yielded approximately 84 %. To evaluate the performance of the enzymatic hydrolysis process in comparison to acid hydrolysis and hydrothermal hydrolysis, an integrated MW-TOPSIS framework was proposed. This framework determined that enzymatic hydrolysis achieved the highest closeness coefficient value (Ri = 0.40), indicating its superiority as the preferred alternative among the tested methods.

The pectinolytic activity of Burkholderia cepacia and its application in the bioscouring of cotton knit fabric.

BACKGROUND: Enzymatic catalysis in different industrial applications is often preferred over chemical methods due to various advantages, such as higher specificity, greater efficiency, and less environmental footprint. Pectinases are a group of enzymes that catalyze the degradation of pectic compounds, the key components of plant middle lamella and the primary cell wall. Pectinases have found applications in multiple industrial processes, including cotton bioscouring, fruit juice extraction and its clarification, plant fiber degumming, paper making, plant biomass liquefaction, and saccharification, among others. The purpose of this study was to taxonomically characterize a bacterial species exhibiting pectinolytic activities and assess its pectinolytic activity qualitatively and quantitatively, as well as test its bioscouring potential. RESULTS: Here, we report that Burkholderia cepacia, a previously unknown species with pectinolytic activity, exerts such activity comparable to commercially used pectinase enzymes in the textile industry, but requires less temperature for activity. CONCLUSION: Quantitative evaluation of enzyme activity indicates the potential of the bacterial species for use in the bioscouring of cotton knit fabric.

Preparation of novel clay/chitosan/ZnO bio-composite as an efficient adsorbent for tannery wastewater treatment.

This study focuses on the preparation of an activated clay/chitosan/ZnO bio-composite using solvent casting method. Clay was activated through microwave radiation using 1 M H2SO4 at a minimum liquid to solid ratio (L/S). Chitosan was extracted from waste prawn shell and ZnO nanoparticles (ZnO-NPs) were synthesized from zinc acetate di-hydrate (Zn (CH3CO2)2·2H2O) using the sol-gel method. The produced bio-composite were characterized using FT-IR, TGA, XRD and SEM. Response surface methodology (RSM) was used for experimental design to find out the optimum conditions, e.g., pH of the solution, dosage of adsorbent and contact time for the removal of methylene blue (MB) and Cr (VI) using MINITAB 18.1 software. The optimum conditions obtained for the highest removal of MB were pH 9.57, dosage 55.44 mg and contact time 114.09 min. Similarly, for the highest removal of Cr (VI) the optimum conditions were pH 3.75, dosage 67.42 mg and contact time 111.27 min. Applying these optimum conditions, the highest removal efficiency for MB and Cr (VI) was obtained at 84.21 % and 82.67 % with 9.57 mg g-1 and 10.45 mg g-1 of adsorption capacity respectively. The adsorption data were studied for both Langmuir and Freundlich isotherm. The value of maximum Langmuir sorption was (qm) 17.346 mg g-1 and 17.621 mg g-1 for MB and Cr (VI) respectively.

Fabrication of Electrospun PLA-nHAp Nanocomposite for Sustained Drug Release in Dental and Orthopedic Applications.

This study describes the fabrication of nanocomposites using electrospinning technique from poly lactic acid (PLA) and nano-hydroxyapatite (n-HAp). The prepared electrospun PLA-nHAP nanocomposite is intended to be used for drug delivery application. A hydrogen bond in between nHAp and PLA was confirmed by Fourier transform infrared (FT-IR) spectroscopy. Degradation study of the prepared electrospun PLA-nHAp nanocomposite was conducted for 30 days both in phosphate buffer solution (PBS) of pH 7.4 and deionized water. The degradation of the nanocomposite occurred faster in PBS in comparison to water. Cytotoxicity analysis was conducted on both Vero cells and BHK-21 cells and the survival percentage of both cells was found to be more than 95%, which indicates that the prepared nanocomposite is non-toxic and biocompatible. Gentamicin was loaded in the nanocomposite via an encapsulation process and the in vitro drug delivery process was investigated in phosphate buffer solution at different pHs. An initial burst release of the drug was observed from the nanocomposite after 1 to 2 weeks for all pH media. After that, a sustained drug release behavior was observed for the nanocomposite for 8 weeks with a release of 80%, 70% and 50% at pHs 5.5, 6.0 and 7.4, respectively. It can be suggested that the electrospun PLA-nHAp nanocomposite can be used as a potential antibacterial drug carrier for sustained drug release in dental and orthopedic sector.

Ecofriendly pretreatment of cotton fabrics by ultrasonication and reusing bath chemicals.

The textile industries of Bangladesh contribute significantly to the country's economy, accounting for more than 40% of total annual export. The quest of new technologies for efficient water and energy use in cotton knit dyeing could result in significant water savings and improve environmental sustainability. Textile wet processing consumes a lot of utilities (water and energy), and the water generates a lot of waste, which enhances chemical consumption and effluent management costs. The cotton knit fabric used in this study was pretreated and dyed utilizing ultrasonication at a lower temperature than conventional pretreatment and dyeing techniques in an attempt to establish ecofriendly wet processing in the textile industry. The bath chemicals were reused up to two times before dyeing in conventional techniques, and fabric properties such as whiteness index, weight loss, bursting strength, color fastness to light, washing, perspiration, rubbing, color strength and durability, or dimensional stability were evaluated and compared with the values obtained by conventional techniques. The color matching of reactive dyed fabric for ultrasonic pretreated fabric with and without reusing bath chemicals was determined. The sonicated scoured and bleached fabric's whiteness index was found to be acceptable, with relatively low weight loss; however, the bursting strength was found to be increased. Color fastness to light, washing, perspiration, and rubbing were found to be comparable to the conventional technique for low temperature ultrasonicated pretreated and reuse-1 pretreated dyed knit fabric. The results also revealed that there was no color degradation during ultrasonication. FT-IR spectroscopy and scanning electron microscopy (SEM) revealed no significant changes in the chemical composition of cellulose or the fabric shape of pretreated and dyed cotton knit fabric after ultrasonication.

Advanced CNC/PEG/PDMAA Semi-IPN Hydrogel for Drug Delivery Management in Wound Healing.

A Semi Interpenetrating Polymer Network (semi-IPN) hydrogel was prepared and loaded with an antibiotic drug, gentamicin, to investigate the wound healing activity of this system. The semi-IPN hydrogel was synthesized by combining natural polymer cellulose nanocrystal (CNC) and synthetic polymer polyethylene glycol (PEG) and poly (N,N'-dimethyl acrylamide) (PDMAA), which was initially added as a monomer dimethyl acrylamide (DMAA). CNC was prepared from locally obtained jute fibers, dispersed in a PEG-NaOH solvent system and then mixed with monomer DMAA, where polymerization was initiated by an initiator potassium persulphate (KPS) and cross-linked by N,N'-methylenebisacrylamide (NMBA). The size, morphology, biocompatibility, antimicrobial activity, thermal and swelling properties of the hydrogel were investigated by different characterization techniques. The biocompatibility of the hydrogel was confirmed by cytotoxicity analysis, which showed >95% survival of the BHK-21, Vero cell line. The drug loaded hydrogel showed antimicrobial property by forming 25 and 23 mm zone of inhibition against Staphylococcus aureus (gram-positive) and Escherichia coli (gram-negative) bacteria, respectively, in antimicrobial analysis. At pH 5.5, 76% of the drug was released from the hydrogel within 72 h, as observed in an in vitro drug release profile. In an in vivo test, the healing efficiency of the drug loaded hydrogel was examined on a mice model with dorsal wounds. Complete healing of the wound without any scar formation was achieved in 12 days, which revealed excellent wound healing properties of the prepared drug loaded semi-IPN hydrogel. These results showed the relevance of such a system in the rapid healing of acute wounds.

Progress in surface-modified silicas for Cr(VI) adsorption: A review.

Various toxic chemicals are discharging to the environment due to rapid industrialization and polluting soil, water, and air causing numerous diseases including life-threatening cancer. Among these pollutants, Cr(VI) or hexavalent chromium is one of the most carcinogenic and toxic contaminants hostile to human health and other living things. Therefore, along with other contaminants, the removal of Cr(VI) efficiently is very crucial to keep our environment neat and clean. On the other hand, silica has a lot of room to modify its surfaces as it is available with various sizes, shapes, pore sizes, surface areas etc. and the surface silanol groups are susceptible to design and prepare adsorbents for Cr(VI). This review emphases on the progress in the development of different types of silica-based adsorbents by modifying the surfaces of silica and their application for the removal of Cr(VI) from wastewater. Toxicity of Cr(VI), different silica surface modification processes, and removal techniques are also highlighted. The adsorption capacities of the surface-modified silica materials with other parameters are discussed extensively to understand how to select the best condition, silica and modifiers to achieve optimum removal performance. The adsorption mechanisms of various adsorbents are also discussed. Finally, future prospects are summarized and some suggestions are given to enhance the adsorption capacities of the surface-modified silica materials.

Gelatin-based instant gel-forming volatile spray for wound-dressing application.

This study was a successful endeavor to develop and investigate the suitability of a bioadhesive wound-healing gel based on gelatin for first-aid purposes. Polyethylene glycol (PEG) was used to prepare a denser phase of gelatin chains, and diethyl ether (DEE) was used to introduce high volatility to the solution. The prepared solution was stable in the storage container but rapidly formed (within 3 s) a protective and bioadhesive gel around the wound surface by being sprayed over the wound. Besides, it also suppressed pain and showed moderate antimicrobial activity against S. aureus. It was also found highly biocompatible and non-toxic. All the results revealed that the prepared solution could be an effective candidate for treating minor injuries or burn, especially for a first-aid purpose.

Remarkable enhancement of thermal stability of epoxy resin through the incorporation of mesoporous silica micro-filler.

For the first time, we incorporated mesoporous micro-silica (5 µm, pore size = 50 nm) as a filler in epoxy resin aiming to enter polymer into the pore of the silica. As expected, the thermal stability of the composite increased remarkably, followed by noteworthy thermal degradation kinetics when compared to the controlled cured epoxy resin. Composites were prepared by the direct dispersion of modified nano-silica, modified mesoporous micro-silica, unmodified mesoporous micro-silica, non-porous micro-silica, and irregular micro-silica of various pore sizes as fillers in diglycidyl ether of bisphenol-A epoxy resin via ultra-sonication and shear mixing, followed by oven-curing with 4,4-diaminodiphenyl sulfone. DSC and TGA analyses demonstrated a higher glass transition temperature (increased by 3.65-5.75 °C) and very high activation energy for thermal degradation (average increase = 46.2%) was obtained for the same unmodified silica composite compared to pure epoxy, respectively.

Preparation of bio-inspired trimethoxysilyl group terminated poly(1-vinylimidazole)-modified-chitosan composite for adsorption of chromium (VI) ions.

Chitosan and poly(1-vinylimidazole) are both potential adsorbents to remove Cr(VI). Here, we designed the preparation of new adsorbents by combining chitosan and poly(1-vinylimidazole) to get the synergistic effect for the removal of hexavalent chromium. Trimethoxysilyl group terminated poly(1-vinylimidazole)-modified-chitosan composite was successfully synthesized by one-step free radical polymerization based on the grafting backbone of chitosan and vinylimidazole. The resulting adsorbents were used for the removal of Cr(VI) ions from the aqueous solution. The modified chitosan composite was characterized by ATR, FTIR, BET isotherm studies, elemental analysis, TGA, DSC, FE-SEM, and EDX. ATR. FTIR results confirmed the presence of the imidazole group in modified chitosan. The adsorption results were described by the Langmuir isotherm model with a maximum adsorption capacity of 196.1 mg/g for modified chitosan, however, the chitosan yielded 151.5 mg/g. It has been observed that the adsorption of chromium fitted better with the pseudo-second-order kinetics. The modified chitosan composite exhibited greater adsorption capacity than chitosan for hexavalent chromium and has potential application for Cr(VI) removal from aqueous solution containing other common ions with regeneration ability. This novel approach of modifying chitosan with telomerized poly(1-vinyl imidazole) offers potential application in wastewater treatment of different industries releasing Cr (VI).

Novel alginate-di-aldehyde cross-linked gelatin/nano-hydroxyapatite bioscaffolds for soft tissue regeneration.

The present study describes the fabrication of a novel alginate-di-aldehyde (ADA) cross-linked gelatin (GEL)/nano-hydroxyapatite (nHAp) bioscaffold by lyophilization process. The physico-chemical properties of the scaffolds were evaluated in order to assess its suitability for tissue engineering application. ADA was prepared from periodate oxidation of alginate which facilitate the crosslinking between free amino group of gelatin and available aldehyde group of ADA through Schiff's base formation. nHAp was synthesized from waste egg-shells by wet chemical method. The synthesized HAp was found crystalline and nanosize (~45 nm) by XRD and TEM analysis respectively. Ca to P ratio of nHAp is 1.51 as observed by EDX confirmed the suitability of the scaffold for biomedical application. The crosslinked ADA increases thermal stability of scaffolds. Water uptake and degradation ability significantly reduced with the increase of nHAp in the scaffold due to the higher stiffness contributed by nHAp. SEM analysis revealed that the pore size and porosity of the scaffolds declines with the proliferation of nHAp in the scaffolds. XRD analysis of the scaffolds shows the increase of crystallinity in the composites due to incorporation of nHAp and ADA. Cytotoxicity of the all scaffolds were examined by normal kidney epithelial cells (Vero cells) and the results confirmed the non-toxicity of the scaffolds, which proved it is extremely cytocompatible. These tunable physical properties and enhance biocompatibility of prepared scaffold offer advance application in soft tissue regeneration and could be a promising candidate for biomedical application.

Facile preparation of an alternating copolymer-based high molecular shape-selective organic phase for reversed-phase liquid chromatography.

The synthesis of a new alternating copolymer-grafted silica phase is described for the separation of shape-constrained isomers of polycyclic aromatic hydrocarbons (PAHs) and tocopherols in reversed-phase high-performance liquid chromatography (RP-HPLC). Telomerization of the monomers (octadecyl acrylate and N-methylmaleimide) was carried out with a silane coupling agent; 3-mercaptopropyltrimethoxysilane (MPS), and the telomer (T) was grafted onto porous silica surface to prepare the alternating copolymer-grafted silica phase (Sil-alt-T). The new hybrid material was characterized by elemental analyses, diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, and solid-state 13C and 29Si cross-polarization magic-angle spinning (CP/MAS) NMR spectroscopy. The results of 13C CP/MAS NMR demonstrated that the alkyl chains of the grafted polymers in Sil-alt-T remained disordered, amorphous, and mobile represented by gauche conformational form. Separation abilities and molecular-shape selectivities of the prepared organic phase were evaluated by the separation of PAHs isomers and Standard Reference Material 869b, Column Selectivity Test Mixture for Liquid Chromatography, respectively and compared with commercially available octadecylsilylated silica (ODS) and C30 columns as well as previously reported alternating copolymer-based column. The effectiveness of this phase is also demonstrated by the separation of tocopherol isomers. Oriented functional groups along the polymer main chains and cavity formations are investigated to be the driving force for better separation with multiple-interactions with the solutes. One of the advantages of the Sil-alt-T phase to that of the previously reported phase is the synthesis of the telomer first and then immobilized onto silica surface. In this case, the telomer was characterized easily with simple spectroscopic techniques and the molecular mass and polydispersity index of the telomer were determined by size exclusion chromatography (SEC) before grafting onto silica surface. Moreover, both of the monomers were commercially available. Therefore, the technique of preparation was very facile and better separation was achieved with the Sil-alt-T phase compared to the ODS, C30 and other previously reported alternating copolymer-based columns.

Core-shell drug carrier from folate conjugated chitosan obtained from prawn shell for targeted doxorubicin delivery.

A multifunctional drug carrier with dual targeting (magnetic and folate-receptor) and pH sensitive core-shell hybrid nanomaterial has been developed to carry an anticancer drug doxorubicin.Superparamagnetic iron oxide nanoparticles (IONPs) were used as core of the carrier and cross-linked folate conjugated chitosan (FA-CS) was acted as shell in which doxorubicin was physically entrapped. Transmission electron microscopy (TEM) analysis confirmed the average particle size of IONPs and FA-CS coated IONPs 8.2 and 15.4 nm respectively. Magnetic measurement indicated that both the IONPs and FA-CS coated IONPs were superparamagnetic at room temperature with a magnetization value 57.72 and 37.44 emu/g respectively. At pH 5.8 (malignant tissue) showed a burst release of 30.05% of the doxorubicin in the first 4 h followed by a sustained release of 88.26% of drug over 72 h. From these results it is expected that doxorubicin loaded nanoparticles can be a promising drug carrier for the treatment of solid tumors with the ability to reduce toxic side effects of drugs by selective targeting and sustained release.

Preparation of Chitin-PLA laminated composite for implantable application.

The present study explores the possibilities of using locally available inexpensive waste prawn shell derived chitin reinforced and bioabsorbable polylactic acid (PLA) laminated composites to develop new materials with excellent mechanical and thermal properties for implantable application such as in bone or dental implant. Chitin at different concentration (1-20% of PLA) reinforced PLA films (CTP) were fabricated by solvent casting process and laminated chitin-PLA composites (LCTP) were prepared by laminating PLA film (obtained by hot press method) with CTP also by hot press method at 160 °C. The effect of variation of chitin concentration on the resulting laminated composite's behavior was investigated. The detailed physico-mechanical, surface morphology and thermal were assessed with different characterization technique such as FT-IR, XRD, SEM and TGA. The FTIR spectra showed the characteristic peaks for chitin and PLA in the composites. SEM images showed an excellent dispersion of chitin in the films and composites. Thermogravimetric analysis (TGA) showed that the complete degradation of chitin, PLA film, 5% chitin reinforced PLA film (CTP2) and LCTP are 98%, 95%, 87% and 98% respectively at temperature of 500 °C. The tensile strength of the LCTP was found 25.09 MPa which is significantly higher than pure PLA film (18.55 MPa) and CTP2 film (8.83 MPa). After lamination of pure PLA and CTP2 film, the composite (LCTP) yielded 0.265-1.061% water absorption from 30 min to 24 h immerse in water that is much lower than PLA and CTP. The increased mechanical properties of the laminated films with the increase of chitin content indicated good dispersion of chitin into PLA and strong interfacial actions between the polymer and chitin. The improvement of mechanical properties and the results of antimicrobial and cytotoxicity of the composites also evaluated and revealed the composite would be a suitable candidate for implant application in biomedical sector.

Preparation of gelatin based porous biocomposite for bone tissue engineering and evaluation of gamma irradiation effect on its properties.

Biodegradable porous hybrid polymer composites were prepared by using gelatin as base polymer matrix, ß-tricalcium phosphate (TCP) and calcium sulfate (CS) as cementing materials, chitosan as an antimicrobial agent, and glutaraldehyde and polyethylene glycol (PEG) as crosslinkers at different mass ratios. Thereafter, the composites were subjected to γ-radiation sterilization. The structure and properties of these composite scaffolds were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), mechanical properties testing (compressive, bending, tensile and impact), thermogravimetry/differential thermal analysis (TG/DTA), and physical stability test in simulated body fluid (SBF). We found that TCP rich composites showed enhanced mechanical properties among all the crosslinked composites. γ-Radiation sterilization triggered further cross linking in polymer matrix resulting a decrease in pore size of the composites and an increase in pore wall thickness with improved mechanical and thermal properties. The chemically crosslinked composite with 40% TCP followed by γ-radiation sterilization showed the smallest pore size distribution with a mean pore diameter of 159.22µm, which falls in the range of 100-350µm - known to be suitable for osteoconduction. Considering its improved mechanical and thermal properties along with osteoconduction ability without cytotoxicity, we propose this biocomposite as a viable candidate for bone tissue engineering.

Characterization of crystalline cellulose of jute reinforced poly (vinyl alcohol) (PVA) biocomposite film for potential biomedical applications.

Cellulose crystals (CC) were chemically derived from jute by alkali treatment, bleaching and subsequent hydrolysis with 40 % sulfuric acid. Infrared spectroscopy (FT-IR) suggested sufficient removal of lignin and hemicellulose from the raw jute and scanning electron microscopy (SEM), and X-ray diffraction (XRD) studies demonstrated the preparation of microcrystalline cellulose. CC reinforced polyvinyl alcohol (PVA) composite was prepared by solution casting method under laminar flow. In order to maintain uniform dispersion of 3-15 % (w/w) of the CC in the composite N, N dimethylformamide (DMF) was used as a dispersant. FT-IR, XRD, SEM, thermogravimetric analysis (TG, DTG and DTA) and thermomechanical analyses (TMA) were used to characterize the CC and the composites. The study of tensile properties showed that tensile strength (TS) and modulus (TM) increase with increasing CC content up to 9 % and then decrease with the addition of a high content of CC (above 9 %) because of the aggregation of CCs in the composite. The highest TS (43.9 MPa) and TM (2,190 MPa) have been shown to be the composite prepared with 9 % CC and the lowest to be from pure PVA film 17.1 and 1470 MPa. In addition, the composites have showed no cytotoxicity that can also prohibit microbial growth and; hence, it can be a potential material for biomedical applications such as wound healing accelerators.

Physico-chemical characteristics of gamma-irradiated gelatin.

This article reports the effects of gamma irradiation (dose ranges 0.1-10 kGy from 60Co source) on the characteristics of solid gelatin and the physico-mechanical, microstructural and bioactive properties of the scaffold prepared from irradiated gelatin solution. FTIR, intrinsic viscosity, bloom strength, thermal properties, SEM, tensile properties, water uptake ability and antimicrobial activities of non-irradiated and irradiated solid gelatin and its scaffolds were investigated. The detailed experimental results for the solid gelatin demonstrated that 1 kGy γ-irradiated samples showed higher intrinsic viscosity, enhanced thermal stability and bloom strength than other irradiated samples. Furthermore, the scaffold thus prepared from irradiated and non-irradiated gelatin also revealed that 1 kGy samples showed the highest tensile strength and modulus with good water resistivity than other irradiated and non-irradiated samples. In addition to the physico-mechanical properties, 1 kGy scaffolds have also exhibited the highest resistivity towards microbial growth that can have potentiality as scaffold in biomedical sector. The enhanced functional and bioactive properties at low irradiation doses (1 kGy) may occurred due to an initial breaking of hydrogen bonds of polypeptide chains in gelatin molecules that indicated by the shift of amide A, I and II peaks to higher wave numbers in FTIR. This enhancement resulted probably due to the domination of crosslinking over degradation at 1 kGy. It was also observed that 1 kGy γ-radiation-induced crosslinking has lowered the hydrophilicity by decreasing water uptake and mean pore diameter of the interconnected porous structures of gelatin.