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Introduction and aim: Osteoarthritis (OA) is the commonest degenerative and painful articular disease. It is a significant cause of disability. Early diagnosis is crucial and searching for biomarkers is continuing. The current work aimed to assessment the plasma leptin and adiponectin concentrations in patients with primary knee osteoarthritis (OA), and to explore the relationship of leptin and adiponectin with OA severity Methodology: Forty patients with primary knee osteoarthritis from both sexes who fulfilled ACR criteria for diagnosis of knee OA were enrolled. Other healthy subjects were included as a control group. Patients were sassed by history taking, clinical examination, radiological and laboratory investigations. WOMAC questionnaire was used to evaluate a patient’s functions. Results: Both study and control groups were comparable as regards to patient demographics, except their weight, height and body mass index (BMI). Obesity, hypertension, tenderness, pain grade, limitation of joint movements and WOMAC score, Kellgren Lawrence radiological criteria, leptin and adiponectin were increased in study when compared to control group. There was significant, positive, moderate correlation between leptin and BMI (r=0.557, p < 0.001). Higher leptin was associated with obesity and diabetes mellitus. Leptin serum levels revealed proportional, moderate, significant correlation with each of pain, stiffness and K-L criteria, while this correlation was powerful with physical function and total WOMAC score. Conclusion: Leptin and adiponectin were increased in patients with osteoarthritis. Leptin alone is significantly associated with disease severity indices.

A photo-active gellan gum (Gel) derivative was developed by amide bond combination with trans-4-[p-(amino)styryl]pyridine (SP). The SP-Gel was cross-linked by UV curing via the intermolecular 2π + 2π cycloaddition of the inserted SP–CH=CH- moieties. The chemical structure of the obtained photo-crosslinkable biopolymer was investigated before and after the UV curing and the progress of the performed 2π + 2π cycloaddition-based cross-linking was detected via UV–visible light spectra. SP-Gel was evaluated as a polymeric matrix for the immobilization of catalase via entrapment technique. The synthesized biopolymer was mixed with the catalase and molded in the form of membranes that were UV cured to encapsulate the enzyme. The membranes were able to entrap 0.75 mg/cm2 with retained activity reached above 95%. The immobilized catalase displayed higher thermal stability and higher resistance toward the environmental pH disturbances compared to the free enzyme. Also, despite the observed lower catalase-H2O2 affinity upon the entrapment that was indicated from the performed kinetic studies, the reusability and storage stability experiments revealed the economic value of the entire process by preserving around 95% and 83% of the initial catalase activity after the fifth and tenth operation cycles, respectively.

The present review has highlighted the chemistry of pyrimido[1,2-a]pyrimidine compounds as one of the most important classes of heterocyclic systems. The main sections include: (1) The synthesis of pyrimido[1,2-a]pyrimidines, (2) reactivity of the substituents attached to the carbon and nitrogen atoms of the ring and (3) biological applications. A discussion demonstrated that the proposed mechanisms of unexpected synthetic routes were intended. The purpose of this review is to provide an overview of the chemistry of pyrimido[1,2-a]pyrimidines to date, in which the compounds should be widely applied in medicinal and pharmaceutical chemistry based on the significant, variable and potent biological results of pyrimidopyrimidine and pyridopyrimidine analogs. This survey will assist scientists in the organic and medicinal chemistry fields to design and develop procedures for the construction of new standard biological compounds.

Heterocycles incorporating a pyrimidopyrimidine scaffold have aroused great interest from researchers in the field of medical chemistry because of their privileged biological activities; they are used as anti-bacterial, antiviral, anti-tumor, anti-allergic, antihypertensive, anticancer, and hepatoprotective agents. Therefore, the present study aims to investigate the chemistry of heterocycles incorporating pyrimido[1,6-a]pyrimidine and pyrimido[1,6-c]pyrimidine skeletons and their biological characteristics. The main sections discuss (1) the synthetic routes to obtain substituted pyrimidopyrimidines, pyrimido[1,6-a]pyrimidin-diones, pyrimidoquinazolines, tricyclic, tetracyclic, and binary systems; (2) the reactivity of the substituents attached to the pyrimidopyrimidine skeleton, including thione and amide groups, nucleophilic substitutions, condensations, ring transformations, and coordination chemistry; (3) compounds of this class of heterocycles containing a significant characteristic scaffold and possessing a wide range of biological characteristics.

In this work, a photo-responsive hydrogel membrane based on cinnamate-modified hyaluronic acid (HA-CM) was developed and safely cross-linked under UV light curing. The obtained material was effectively utilized for immobilization of horseradish peroxidase (HRP) enzyme via encapsulation and entrapment strategy with efficiency above 95%. The prepared HA-CM biopolymer was investigated before the UV curing using instrumental and spectral techniques including Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR). During the UV irradiation, the progress of the cross-linking reaction was monitored by the UV–vis light spectroscopy. In addition, when the photo-induced cross-linking had accomplished, the morphological appearance of the hydrogel membrane was recorded using a scanning electron microscope (SEM). The HRP immobilized in HA-CM membranes displayed remarkable stability against the environmental pH changes especially under alkaline media and shift the optimum pH to 8 compared to the free HRP, which exhibited the highest activity at pH 7. Also, the entrapped enzyme was able to preserve above 85% of its catalytic activity at higher temperature values where the free enzyme had deactivated by approximately 50%. Moreover, HA-CM-HRP maintained 87% of its activity after 10 sequential reuse cycles, which indicate the economic value of the employed immobilization strategy.

The aim of this work is to discuss the chemistry of pyrido[3,4-d]pyrimidines as one of the most important heterocyclic compounds with remarkable synthetic, biological and medical applications. In this overview, the chemistry of heterocyclic compounds incorporated the pyrido[3,4-d]pyrimidine scaffold as demonstrated by chemical reactions and different preparation processes. The anticipated compounds were synthesized from pyridine or pyrimidine compounds and a description of the reactivity of substituents attached to ring carbon and nitrogen atoms is discussed. On the other hand, the synthesis and reactions of fused heterocycles incorporated pyrido[3,4-d]pyrimidine scaffold is described. The diamine analogs included pyrido[3,4-d]pyrimidine core were reported as tyrosine kinase inhibitors. The chemical reactions of certain unexpected and chemically substantial compounds have been discussed.

The present study describes recent advances in the chemistry of heterocycles incorporated oxazolo[4,5-b]pyridine and oxazolo[5,4-b]pyridine skeletons. The main sections included the synthesis of th...

The present review highlights the synthetic procedures reported for the preparation of oxazolo[3,2-a]pyridines as a class of 5-6 bicyclic heterocycles with a nitrogen atom at the ring junction. The...

A photo-crosslinkable hydrogel derived from cinnamoyl modified alginate (Alg-CN) was prepared via hydrazide intermediate and employed as an efficient drug carrier using the painkiller drug paracetamol. Methyl ester of the alginic acid was first prepared and converted into the corresponding hydrazide intermediate (Alg-Hyd) and then the cinnamoyl units were incorporated using cinnamoyl chloride. The synthesized derivatives were characterized by spectral and instrumental methods to confirm their suggested chemical structures. The obtained Alg-CN derivatives displayed initiator-free crosslinking capabilities upon the UV exposure for adequate periods of time, which was demonstrated due to the formation of cyclobutane bridges connecting the alginate polysaccharide chains through the [2π+2π] cycloaddition reaction carried out by the CHCH units of the inserted cinnamoyl moieties. The cross-linking of the Alg-CN was monitored by observing the lowering of the UV spectral band related to the cinnamoyl units and then the gelation efficiency along with the swelling degree was investigated over the UV light exposure time. Moreover, the developed hydrogel derivatives present considerable potentials as drug carriers that enable the control of the drug release by varying the degree of hydrogel cross-linking either by cinnamoyl functionalization or UV light exposure time.

The present study provides an overview of the chemistry and biological significance of pyrimido[4,5-d]pyrimidine and pyrimido[5,4-d]pyrimidine analogs as types of bicyclic [6 + 6] systems. The main sections include: (1) synthesis methods; (2) the reactivities of the substituents linked to the ring carbon and nitrogen atoms; and (3) biological applications. A discussion demonstrating the proposed mechanisms of unexpected synthetic routes is intended. The aim of this study is to discuss the synthetic significance of the titled compounds and to establish the biological characteristics of this class of compounds as studied to date, where the compounds have been applied on a large scale in the medical and pharmaceutical fields. This survey will help researchers in the fields of synthetic organic and medicinal chemistry to undertake and improve new approaches for the construction of new standard biological components.

An isatin functionalized chitosan derived ion-imprinted adsorbent (Cu-CIS) was designed by tailoring Cu(II) ions imprinted cavities within the modified polysaccharide network matrix that are able to capture Cu(II) ions selectively in aqueous solution. The chelating power of chitosan toward the Cu(II) ions was first enhanced via isatin functionalization, which was cross-linked using epichlorohydrin (ECH) after loading the Cu(II) ions. The selective metal ions binding sites are then formed by eluting the coordinated Cu(II) ions using EDTA to finally produce the Cu-CIS selective sorbent. The equilibrium isotherms have been utilized to anticipate the maximum capacity of the Cu-CIS sorbent and compare it with that of the blank non-imprinted sorbent NI-CIS. In addition, the significance of inserting the Cu(II) ions recognition cavities within the adsorbent matrix was pointed out by performing the adsorption in a multi-ionic solution mixture containing Co(II), Ni(II), Pb(II), Cd(II) and Cu(II) ions and the obtained selectivity coefficients in case of Cu-CIS revealed remarkable selectivity potentials toward the Cu(II) ions compared to NI-CIS. Moreover, at the consecutive performance of a Cu-CIS absorbent for five cycles, it was found that it still held 97% of its initial capacity enabling promising applications in both water treatment and Cu (II) ions recycling.

This review describes the chemistry of 2,3-dihydroxynaphthalene and the related analogues. The synthetic routes reported to obtain the investigated structures are discussed. In addition, the reacti...

Jack bean urease (EC.3.5.1.5) was effectively immobilized onto amino functionalized epichlorohydrin cross-linked carboxymethyl cellulose (ECH-CMC) beads that were fabricated by graft co-polymerization of polyacrylamide (PAm) onto ECH-CMC beads in presence of potassium persulfate (KPS)/thiourea (TU) combined redox initiator followed by Hoffmann degradation. The progress of the synthesis along with immobilization processes was investigated by FTIR spectra. Also, the morphological structures of the beads before and after urease immobilizations were examined using SEM. Immobilization efficiency and immobilized urease amounts were estimated as a function of the amino functionalization degrees. The effects of pH and temperature on urease activity were studied. The results showed that after immobilization the optimum pH and temperature displayed higher shifts to 8 and 45°C, respectively, which reveal a higher structural stability upon immobilization performance. Moreover, the kinetic studies indicated that the urea hydrolysis reaction, which catalyzed by urease enzyme displayed a good fit with Michaelis-Menten equation, and the kinetic parameters Km and vm were estimated to be 14±0.7mM and 2±0.2μmolNH3/min·mg immobilized urease, respectively. Furthermore, the immobilized urease maintained approximately 88% of its initial activity after the 10th reuse cycle.

An enantio-selective l -histidine imprinted polymeric resin was fabricated and evaluated for enantiomeric resolution of histidine racemate. The polymerizable chiral salicyloyl- l -histidine amide was first synthesized and anchored onto a polymeric resin network via condensation polymerization with resorcinol and formaldehyde. l -histidine template molecules were then extracted out of the resin texture via alkaline hydrolysis of the amide bond using sodium hydroxide. The synthetic steps were monitored by means of instrumental techniques including elemental analysis; mass spectra along with both Fourier transform infrared and nuclear magnetic resonance spectroscopy. In addition, the surface morphologies of both imprinted and non-imprinted resins were visualized using scanning electron microscope and the images indicated a relatively rougher surface in case of the imprinted resin. Also, the complete extraction of the template l -histidine molecules was assured using energy-dispersive X-ray spectroscopy, which indicated the absence of nitrogen upon alkaline treatment of the synthesized l -histidine containing resin. Selective adsorption experiments indicated that the maximum adsorption was achieved at pH 8 and followed the pseudo-second-order kinetic model with extracted amounts of 165 ± 1 and 90 ± 1 mg/g with respect to l - and D-histidine, respectively. Moreover, Langmuir model displayed the best fit with the experimentally obtained isotherm data and the maximum adsorption capacities were 195 ± 1 and 102 ± 1 mg/g with respect to l - and d - histidine, respectively. The enantiomeric resolution of d / l -histidine racemate was also carried out utilizing a column backed with the imprinted resin and the outlet collected solution displayed an optical activity related to 36% d -histidine enantiomeric excess.

This review described the synthetic methods, chemical reactivity and biological applications of furan carboxamide compounds. Furan-carboxamides are reported to have important and variable biologica...

Cd(II)-imprinted Cd(II) resin obtained from a thiosemicarbazide derivative of salicylic acid was prepared and evaluated for selective uptake of Cd(II) ions. In the beginning, the thiosemicarbazide derivative of salicylic acid (H2TCS) was developed as a functional ligand that was then coordinated with Cd(II) ions to obtain the Cd-complex [CdTCS(H2O)3]. After the full investigation of the ligand and its complex, they copolymerized with resorcinol in presence of formalin, and the obtained resinous material was eluted with 0.1 M HNO3 solution to extract the polymer incorporated Cd(II) ions and finally produce the Cd(II) ions selective Cd-RTCS sorbent. The maximum cadmium ions capacity by the Cd-RTCS reached 164 ± 1 mg/g, which could be a relatively high and promising value. Also, the adsorption isotherms were interpreted better with the Langmuir model. In addition, the Cd(II) sorption using Cd-RTCS was tested in a competitive medium of Pb(II), Ni(II), Zn(II), and, Cu(II) ions and the results indicated a considerable selectivity toward the Cd(II) ions over the coexisted metals.

S-Mandelic acid (MA) enantio-selective resinous material functionalized with –NH2 groups has been developed and effectively utilized in chiral separation of (±)-MA racemate solution. S-MA has first combined with the polymerizable p-aminophenol and form the corresponding amide derivative, which was then polymerized with phenol/formalin using HCl as a catalyst. The stereo-selective –NH2 functionalized binding sites were then generated within the resin upon the alkaline degradation of the amide linkages followed by acidic treatments that will expel the resin incorporated S-MA out of the polymeric material to get the S-MA imprinted polymer (S-MAPR). The synthesized S-MA chiral amide derivative along with the developed polymeric resin was investigated by various techniques including FTIR and NMR spectra that confirmed the executed chemical modifications. In addition, the morphological appearance of the obtained resins were observed using SEM images. Moreover, the S-MAPR resin was examined to optimize the enantio-selective separation conditions and the studies indicated that the adsorption reached the highest value at pH 7 and the maximum capacity was 243 ± 1 mg/g. In addition, the chiral separation of (±)-MA racemic solution was successfully executed by the S-MAPR separation column with 55% and 82% enantiomeric excess of R- and S-MA within both the initial loading and recovery eluant solutions, respectively.

Ion-imprinting strategy was utilized in the development of UO2(II) imprinted amidoxime modified chitosan sorbent (U-AOCS) that can selectively remove UO2(II) from water. First, cyanoactic acid was linked to the chitosan -NH2 groups and then the inserted -CN groups were converted into amidoxime moieties, which chelate the UO2(II) ions and then the polymer chains were cross-linked by glyoxal. The UO2(II) ions have been then eluted leaving their matching recognition sites. The prepared U-AOCS along with the control NIP displayed maximum capacities toward the UO2(II) ions around 332 and 186 mg/g, respectively, and the isotherms were interpreted better by the Langmuir model in both adsorbents. Moreover, the selective uptake of the uranyl ions in multi-ionic aqueous solutions containing the tetravalent Th(IV) ions, trivalent Al(III), Eu(III), and Fe(III) ions, beside the divalent Pb(II), Co(II), Ni(II), Cu(II) ions confirmed the successful creation of a considerable UO2(II) ions selectivity in the U-AOCS construction. In addition, the U-AOCS adsorbent displayed economic feasibility by maintaining around 95 % of its initial efficiency after the regeneration and reuse for 5 adsorption/desorption cycles.

In this work, a selective Pd(II) ions chelating resin based on 2-aminobenzaldehyde modified chitosan Schiff's base (Pd-CAZ) was synthesized through ion-imprinting technique. All the performed chemical and morphological changes during the modification and Pd(II) ion-imprinting process were investigated using instrumental techniques including FTIR, (1)H NMR, XRD and SEM. In addition, the mechanism of Pd(II) binding to the synthesized polymeric active sites was elucidated using both XPS and FTIR spectra, and the results indicated that Pd(II) ions coordinated in square planar geometry. Also, the selective extraction experiments with respect to Pd-CAZ and control non-imprinted NI-CAZ resins were performed to obtain the fundamental thermodynamic, kinetic and isotherm parameters. In all cases the adsorption was endothermic, spontaneous, fit well with pseudo-second order kinetic model and Langmuir adsorption isotherm model with maximum adsorption capacities of 275±0.4 and 114±0.2 mg/g for Pd-CAZ and NI-CAZ, respectively. Moreover, the regeneration and recovery experiments indicated that the resin maintain about 96% of its original activity after the fifth adsorption-desorption cycle, revealing the high economic value.

An ion-imprinted sorbent (Ni-CDMO) derived from diacetylmonoxime (DMO)-chitosan Schiff base has been prepared by incorporating Ni(II) ion matching sites, which can selectively coordinate and recover Ni(II) ions from aquatic media. The chitosan was first modified by DMO to improve the targeted Ni(II) ion coordination and then the polymeric Ni-complex was treated with glyoxal to cross-link the polysaccharide chains and maintain the coordination sites rigid and inflexible after eluting the Ni(II) ions from the sorbent matrix. The maximum Ni(II) ion capacities of the Ni-CDMO and the control adsorbent C-CDMO were determined by performing the isotherm studies under different Ni(II) initial concentrations and treating the obtained experimental results using Langmuir and Freundlich models. The maximum capacity was around 135 mg/g, which is considered a high competing value. Furthermore, the competitive extraction of Ni(II) ions among various similar ions including Pb(II), Cu(II), Co(II), and Cd(II) was carried out using Ni-CDMO and C-CDMO and the results confirmed the distinct role of the utilized imprinting procedure in creating a considerable Ni(II) ion selectivity within the structure of the Ni-CDMO. Also, the regeneration and reusability experiments indicated the preservation of approximately 98% of the initial efficiency after the performance of five consecutive cycles.

Steroids are components of cell membranes, signaling molecules and are a type of secondary metabolites as a result of their high impact of biological significance. The present review described the literature reports of pentacyclic steroidal pyrimidines as a type of heterocyclic steroids. The main sections included the synthesis of the investigated steroids fused at rings-A or B or D of steroid skeleton, synthesis of binary or linked-type pyrimidines, pyrimidine oxides, macromolecules and mono- or di- or tri-peptides linked-steroidal pyrimidines. Besides, the present research highlighted the biological significance of steroidal pyrimidines, in which the compounds revealed potent anticancer, antioxidant, antibacterial, and anti-Alzheimer agents. In addition, some hetero-steroids were screened for binding DNA assay and gene expression analysis. It was settled that the incorporation of pyrimidine scaffold into steroid basic skeleton is crucial for better biological results.

In the present study, a sulfonic acid functionalized enantio-selective resinous material was developed for effective chiral separation of (±)-methamphetamine racemate. R-methamphetamine-sulfonamide phenolic derivative was first prepared and fully characterized utilizing instrumental and spectroscopic techniques, then the sulfonamide was implemented in an acid catalyzed condensation copolymerization with phenol and formaldehyde. The resulted resinous material was then exposed to successive alkaline and acidic treatments in order to remove the R-methamphetamine enantiomer out of the resin matrix and obtaining the molecularly imprinted enantio-selective material, which was also investigated by scanning electron microscope, FTIR and XPS spectroscopy. The maximum selective extraction of the R-methamphetamine enantiomer was achieved at pH 7. The adsorption isotherms indicated an adsorption capacity of 233 ± 1 mg/g and followed the well-known Langmuir model. Also, the enantio-separation experiment of the racemic mixture was performed by column technique and both the supernatant loading and the eluant recovery solutions indicated an enantiomeric excess of 80% and 67% related to S- and R-methamphetamine, respectively.

In the present study, Hg(2+) ion-imprinted chelating fibers based on thiourea modified natural cellulosic cotton fibers (Hg-C-TU) were synthesized and characterized using some instrumental techniques such as elemental analysis, scanning electron microscopy (SEM), FTIR, wide angle X-ray and XPS spectroscopy. The modified Hg-C-TU fibers were employed for selective removal of Hg(2+) from aqueous solution. Effect of some essential parameters such as pH, temperature, adsorption times and adsorbate concentration were examined to evaluate the optimum adsorption condition. The adsorption kinetics followed the second-order kinetic model indicating that the chemical adsorption is the rate limiting step. Also, the adsorption isotherm experiments showed the best fit with Langmuir model with maximum adsorption capacities 110.3 and 61.8 mg/g for both Hg-C-TU and NI-C-TU, respectively.

In this work, native cellulose cotton fibers were first modified through graft copolymerization of polyacrylonitrile (PAN) and then by insertion of phenyl thiosemicarbazide moieties to finally produce C-PTS chelating fibers, which were fully characterized using various instrumental techniques such as SEM, FTIR, EDX and XRD spectra. The obtained C-PTS were employed in removal and extraction of Au(3+), Pd(2+) and Ag(+) precious metal ions from their aqueous solutions using batch experiments. The kinetic studies showed that the pseudo-second-order model exhibited the best fit for the experimental data. In addition, the adsorption isotherm studies indicated that the adsorption follows the Langmuir model and the maximum adsorption capacities for Au(3+), Pd(2+) and Ag(+) were 198.31, 87.43 and 71.14 mg/g respectively.

In the current work, we prepared an enantio-selective imprinted resin adsorbent ((+)-EMIP) with remarkable affinity for (+)-ephedrine ((+)-Eph) enantiomer. The phenolic amide derived from 4-hydroxybenzoic acid (HBA) and (+)-Eph ((+)-Eph-HBA) was first synthesized via N,N′-diisopropylcarbodiimide (DIC) activation and then copolymerized with resorcinol and formalin. The template (+)-Eph was then expelled from the resin by alkaline degradation of the amide linkage and the finally obtained (+)-EMIP resin particles exhibited a considerable selectivity toward the (+)-Eph with a capacity reached 220 ± 1 mg/g. Also, the selectivity studies indicated a higher affinity toward the imprinted (+)-Eph enantiomer as a result of the formation of configuration-matching receptor sites that were able to fit the targeted enantiomer better than its mirror-image. Moreover, the prepared resin was successfully employed in the chiral resolution of (±)-Eph racemate using batch technique with (+)-Eph 87.1% enantiomeric excess in the loading supernatant solution and (−)-Eph 44.6% excess in the recovery eluant solution.

A polymeric support based on the natural silk fibers was prepared and characterized for covalent immobilization of b-galactosidase from Escherichia coli. The silk fibers were grafted using polyacrylonitrile in presence of benzophenone as a photo-initiator. The grafted fibers were then activated by treatment with hydrazine hydrate followed by glyoxal cross-linker. FTIR spectra, scanning electron microscope (SEM) in addition to the staining test derived from the Coomassie protein assay were utilized for investigation of the modification and immobilization steps. Also, the activity of both free and immobilized b-galactosidase was evaluated as a function of the various important parameters like grafting percentage, pH, and temperature. In addition, the kinetic parameters Km and vmax for both free and immobilized enzyme were anticipated using Michaelis-Menten equation. The results in this study indicated that the prepared modified woven silk fibers could be used effectively as a polymeric support for immobilization of b-galactosidase. V C 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2923-2931, 2013

The surface ion-imprinted poly(ethylene terephthalate)-thiosemicarbazide modified chelating fibers (Hg-PET-TSC) was prepared using Hg(II) as a template and formaldehyde as a cross-linker and showed higher adsorption capacity and selectivity for the Hg(II) ions compared with the non-imprinted fibers (NI-PET-TSC) without a template. The results showed that the adsorption of Hg(II) on the fibers was affected by the initial pH value, the initial Hg(II) concentration, as well as the temperature. Both kinetics and thermodynamic parameters of the removal process were evaluated and the obtained results indicated a spontaneous exothermic adsorption process that fit with the second-order kinetic model. Equilibrium experiments were fitted in both Langmuir and Freundlich adsorption isotherms and fits well with the Langmuir isotherm equation for the monolayer adsorption process. The maximum adsorption capacity values for Hg-PET-TSC and NI-PET-TSC were 137.13 mg/g and 77.51 mg/g, respectively. The selectivity coefficient of Hg(II) ions and other metal ions on Hg-PET-TSC indicated an overall preference for Hg(II) ions. Desorption studies revealed that HCl or EDTA solutions were the best eluents for the regeneration of the Hg-PET-TSC ion-imprinted chelating fibers.

An enantioselective S-mandelic acid (S-MA) imprinted chitosan (SMIC) was prepared by cross-linking of chitosan using formaldehyde cross-linker, in the presence of S-MA as an imprint template molecule and 0.5% acetic acid solution as a solvent. Non-imprinted cross-linked chitosan (NIC) as control was also prepared by the same procedure in absence of template molecules. The surface morphology of both SMIC and NIC were examined by scanning electron microscope (SEM). SMIC particles were applied to determine the optimum operational condition for S-MA separation from dilute aqueous solution. In adsorption step, optimum pH and retention time were 3.5 and 60 min, while corresponding values in extraction step were 1 and 40 min, respectively. Also, the adsorption isotherms indicated that the maximum adsorption capacities of S- and R-MA on SMIC were 100 ± 0.5 and 64 ± 0.8 mg/g, respectively, while in the case of NIC, both R- and S-MA present the same maximum adsorption.

Photo-active trans-3-(4-pyridyl)acrylic acid (PYA) modified chitosan (CSPA) was synthesized with different functionalization degrees and extensively examined using Fourier transform infrared spectra (FTIR), 1H and 13C nuclear magnetic resonance (NMR) in order to elucidate the chemical structure of the modified biopolymer. The modified CSPA with various substitution degrees were casted in form of thin membranes and cross-linked under photo-chemical condition by exposure to ultra-violet light via [2π+2π] cycloaddition reaction of the incorporated PYA units. The photo-induced reaction was examined using UV-vis light spectra and the cross-linked hydrogel were investigated using both XRD and scanning electron microscope (SEM). Also, the mechanical properties of the hydrogel membranes were studied by measuring the variations of both tensile strength and elongation against corss-linking densities.

An enantioselective l -aspartic acid imprinted chitosan (LAIC) was prepared by cross-linking of chitosan by glyoxal cross-linker, in the presence of l -aspartic acid as an imprinted template molecule and 1% acetic acid solution as a solvent. Non-imprinted cross-linked chitosan (NIC) as control was also prepared by the same procedure in the absence of template molecules. The surface morphology of both LAIC and NIC was examined by scanning electron microscope (SEM). LAIC particles were applied to determine the optimum operational condition for l -aspartic acid separation from dilute aqueous solution. In adsorption step, optimum pH and retention time were 5 and 90 min, while corresponding values in extraction step were 2 and 50 min, respectively. Also, the adsorption isotherms indicated that the maximum adsorption capacities of l- and d -aspartic acid on LAIC were 48 ± 0.7 and 27 ± 1 mg g−1, respectively, while in the case of NIC, both l - and d -aspartic acid present the same maximum adsorption capacity 9 ± 0.8 mg g−1, which confirms that the molecular imprinting technique creates an enantioselectivity of LAIC toward l -aspartic acid. In addition, chiral resolution of l , d -aspartic acid racemic mixture was carried out using column of LAIC.

The graft copolymerization of ethyl acrylate (EA) onto natural wool fibers initiated by potassium persulphate and Mohr's salt redox initiator system in limited aqueous medium was carried out in heterogeneous media. Ester groups of the grafted copolymers were partially converted into hydrazide function groups followed by hydrazone formation through reaction with isatin. Also the application of the modified fibers for metal ion uptake was studied using Cu(II), Hg(II) and Ni(II). The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction.

A method has been developed to immobilize horseradish peroxidase (HRP) on modified chitosan beads by means of graft copolymerization of polyethylacrylate in presence of potassium persulphate and Mohr's salt redox initiator. The activity of free and immobilized HRP was studied. FTIR spectroscopy and scanning electron microscopy were used to characterize HRP immobilization. The efficiency of the immobilization was investigated by examining the relative enzymatic activity of free enzyme before and after the HRP immobilization. The obtained values were found to reach 98.4%. The results show that the optimum temperature of immobilized HRP was 45 degrees C, which was identical to that of free enzyme, and the immobilized HRP exhibited a higher relative activity than that of free HRP over 45 degrees C. The optimal pH for immobilized HRP was 10, which was higher than that of the free HRP (pH 9.0), and the immobilization resulted in stabilization of enzyme over a broader pH range. The apparent kinetic constant value (K(m)) of immobilized HRP was 3.784 mmol ml(-1), which was higher than that of free HRP. On the other hand, the activity of immobilized HRP decreased slowly against time when compared to that of the free HRP, and could retain 65.8% residual activity after 6 consecutive cycles.

In order to develop a non toxic and biocompatible hydrogel system with potential ability in biotechnology, modified photo-crosslinkable hydrogel membranes based on chitosan were prepared. Using an EDC/NHS conjugation method, chitosan was chemically modified to incorporate a photosensitive α-cyano-4-hydroxycinnamic acid moiety with various degrees of substitutions. Fourier transform infrared spectra (FTIR), proton nuclear magnetic resonance (1H NMR) and ultraviolet–visible light spectra (UV–vis) were used for structural characterization of modified chitosan, The obtained membranes were crosslinked by irradiation in the ultraviolet region, where the photosensitive monomers showed maximum sensitivity. The prepared photo-crosslinked hydrogel membranes were investigated by thermal gravimetric analysis (TGA) and wide angle X-ray diffraction (WAXD). The swelling behaviors were investigated in terms of pH, time of swelling, and degree of substitution. Also, mechanical properties of the different photo-crosslinked hydrogel membranes were studied in both dry and wet conditions.

A method has been developed to immobilize lipase from Candida rugosa on modified natural wool fibers by means of graft copolymerization of poly ethylacrylate in presence of potassium persulphate and Mohr’s salt redox initiator. The activities of free and immobilized lipase have been studied. FTIR spectroscopy, scanning electron microscopy, and the Bradford method were used to characterize lipase immobilization. The efficiency of the immobilization was evaluated by examining the relative enzymatic activity of free enzyme before and after the immobilization of lipase. The results showed that the optimum temperature of immobilized lipase was 40 °C, which was identical to that of the free enzyme, and the immobilized lipase exhibited a higher relative activity than that of free lipase over 40 °C. The optimal pH for immobilized lipase was 8.0, which was higher than that of the free lipase (pH 7.5), and the immobilization resulted in stabilization of enzyme over a broader pH range. The kinetic constant value (km) of immobilized lipase was higher than that of the free lipase. However, the thermal and operational stabilities of immobilized lipase have been improved greatly.

Chitin was extracted from shrimp shell waste and its heterogeneous alkaline deacetylation under phase transfer catalysis (PTC) condition was performed. The reaction followed the first-order kinetics during an initial period. The influences of type and concentration of phase transfer catalyst, type of organic solvent, alkaline concentration, temperature, time and volume of organic phase to the volume of aqueous phase ratio on the N -deacetylation were investigated. The degree of deacetylation (DD) increased mainly with increasing temperature, catalyst concentration and time. In the temperature range of 30–100 °C, the apparent rate constant and the activation energy of the reaction were evaluated in presence and in absence of PTC condition.

In this article photo-crosslinkablestyryl-pyridine modified alginate (ASP-Alg) was prepared and entirely investigated utilizing different instrumental techniques such as Elemental analysis, Fourier transform infrared (FTIR),(13)C and (1)H nuclear magnetic resonance (NMR), ultraviolet-visible light (UV-vis), X-ray diffraction (XRD) spectra and scanning electron microscope (SEM). Upon irradiation in the UV region, the casted ASP-Alg membranes were cross-linked through the [2π+2π] cycloaddition reaction of the inserted photo-active styryl pyridine moieties. Both cross-linking density and kinetics were monitored by examining the UV-vis light spectra of the irradiated membrane at predetermined time intervals and the obtained results were found to fit with the second order mathematical kinetic model, revealing the performance of the cross-linking via bimolecular [2π+2π] cycloaddition reaction. Also, the swelling behaviors along with biodegradability were also studied, and the results indicated the decrease of the swelling ratio and degradation rate by increasing the cross-linking density. Moreover, the mechanical properties were also examined under both wet and dry conditions.

Surface ion-imprinted amino-functionalized cellulosic fibers (Cu-ABZ) were manufactured for efficient selective adsorption of Cu(2+) ions. The chemical modification steps had been characterized utilizing elemental analysis; Fourier transforms infrared (FTIR) along with wide angle X-ray diffraction (XRD) spectroscopy. Also, the morphological structure of the ion-imprinted and the non-imprinted (NI-ABZ) fibers were visualized and compared with that of the native cotton fibers using scanning electron microscope (SEM). In addition, the coordination mode by which the Cu(2+) ions bonded to the active sites were examined by both FTIR and X-ray photo electron spectra (XPS). Both Cu-ABZ and NI-ABZ were implemented in batch experiments for optimizing the conditions by which the Cu(2+) ions can be selectively removal from aqueous medium and pH 5 was the optimum for the metal ion extraction. Moreover, the kinetics and isotherm studies revealed that the adsorption data fitted with pseudo-second-order kinetic and Langmuir models with estimated maximum adsorption capacity 93.6mg/g. Also, the reusability studies indicated that the prepared ion-imprinted adsorbent maintains more than 95% of its original activity after fifth generation cycle.

In this work, uranyl complex with Schiff base derived from condensation of p-aminostyrene and salicyaldehyde (HASS) was synthesized. Both ligand and uranyl complex were characterized using elemental analysis, FTIR, (1)H and (13)C NMR spectra. The complex was then copolymerized with styrene and divinylbenzene cross-linker using potassium persulfate free radical initiator through emulsion polymerization technique. The uranyl ions were then leached out from the cross-linked network to finally produce uranyl ion-imprinted microspheres (U-PASS), which were investigated using SEM and FTIR. The effect of various significant parameters such as pH, temperature, contact times and initial uranyl concentration on the removal of uranyl from aqueous solution was examined and the results indicated that the adsorption was exothermic in nature and the kinetics of adsorption fit with the second-order kinetic model. Also, Langmuir adsorption isotherm exhibited the best fit with the experimental results with maximum adsorption capacity 147.8 mg/g. Moreover, the selectivity studies revealed that the ion-imprinted microspheres resin exhibited an obvious affinity toward the uranyl ions in presence of other interfering metal ions compared to the non-imprinted resin.

A new chelating fiber (PET-TSC) was prepared with PET for fast removal of Hg 2+ , Cu 2+ and Co 2+ from water. Elemental analysis, SEM, BET surface area, 13 C NMR, FTIR and X-ray diffraction spectra were used to characterize PET-TSC. The higher uptake capacity of the studied metal ions was observed at higher pH values. Kinetic study indicated that the adsorption of Hg 2+ , Cu 2+ and Co 2+ followed the pseudo-second-order equation, suggesting chemical sorption as the rate-limiting step of the adsorption process. The best interpretation for the equilibrium data was given by Langmuir isotherm, and the maximum adsorption capacities were 120.02, 96.81 and 78.08 mg/g for Hg 2+ , Cu 2+ and Co 2+ ions, respectively. 1 M HCl or 0.1 M EDTA could be used as effective eluant to desorb the Hg 2+ , Cu 2+ and Co 2+ adsorbed by PET-TSC, and the adsorption capacity of PET-TSC for the three heavy metal ions could still be maintained at about 90% level at the 5th cycle. Accordingly, it is expected that PET-TSC could be used as a promising adsorbent for fast removal of heavy metal ions from water, and the present work also might provide a simple and effective method to reuse the waste PET fibers.

Cotton fibers were first grafted by polyacrylonitril in the presence of KMnO(4) and oxalic acid as a combined redox initiator. Moreover, modification of the grafted cotton fibers was done by changing the nitrile group (-CN) into hydrazidine group through the reaction with hydrazine hydrate, then the fibers were activated by glutaraldehyde to introduce free aldehyde groups which were able to react with amino groups of urease to form Schiff's base, and result in cotton fibers immobilized urease. The efficiency of the immobilization was evaluated by examining the relative enzymatic activity of enzyme before and after the immobilization of urease. The results showed that the optimum temperature of immobilized urease was 35°C, which was higher than that of the free enzyme (30°C), and the immobilized urease exhibited a higher relative activity than that of free urease over 35°C. The optimal pH for immobilized urease was 6.5, which was lower than that of the free urease (pH 7.0), and the immobilization resulted in stabilization of enzyme over a wider pH range. The kinetic constant value (K(m)) of immobilized urease was higher than that of the free urease. However, the thermal and operational stabilities of immobilized urease have been improved greatly.