Eco-friendly synthesis of mesoporous bioactive glass ceramics and functionalization for drug delivery and hard tissue engineering applications.

Hard tissue regenerative mesoporous bioactive glass (MBG) has traditionally been synthesized using costly and toxic alkoxysilane agents and harsh conditions. In this study, MBG was synthesized using the cheaper reagent SiO2by using a co-precipitation approach. The surface properties of MBG ceramic were tailored by functionalizing with amino and carboxylic groups, aiming to develop an efficient drug delivery system for treating bone infections occurring during or after reconstruction surgeries. The amino groups were introduced through a salinization reaction, while the carboxylate groups were added via a chain elongation reaction. The MBG, MBG-NH2, and MBG-NH-COOH were analyzed by using various techniques: x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), scanning electron microscopy and energy-dispersive x-ray spectroscopy. The XRD results confirmed the successful preparation of MBG, and the FTIR results indicated successful functionalization. BET analysis revealed that the prepared samples were mesoporous, and functionalization tuned their surface area and surface properties. Cefixime, an antibiotic, was loaded onto MBG, MBG-NH2, and MBG-NH-COOH to test their drug-carrying capacity. Comparatively, MBG-NH-COOH showed good drug loading and sustained release behavior. The release of the drug followed the Fickian diffusion mechanism. All prepared samples displayed favorable biocompatibility at higher concentration in the Alamar blue assay with MC3T3 cells and exhibited the good potential for hard tissue regeneration, as carbonated hydroxyapatite formed on their surfaces in simulated body fluid.

Exploring the Mechanism of Anionic Chemosensing by Imidazoles: A Review.

Chemosensing of ions has gained considerable attention by chemists. Insight into the mechanism involved between sensors and ions always fascinates researchers to develop economical, sensitive, selective, and robust sensors. This review comprehensively explores the mechanism of interaction between Imidazole sensors and anions. With most of the research concentrating only on fluoride and cyanide, this review has highlighted a large gap in various anions detection including SCN-, Cr2O72-, CrO42-, H2PO4-, NO2-, and HSO4-.This study also includes a critical analysis of different mechanisms and their respective limits of detection, with a discussion of the reported results.

Investigation and Discrimination of Ballpoint Pen Inks by Analytical Techniques and Chemometrics.

A population study has been performed for Pakistani ballpoint pen inks of blue, black, red, and green colors (a total of four colors) commercially used in Pakistan. Ballpoint pen inks have been investigated and discriminated by using UV/Vis spectroscopy and FTIR spectroscopy. We have calculated and compared the results in terms of discriminating power (DP). The statistical techniques of principal component analysis and cluster analysis have been applied on obtained data. By visual comparison, the best DP is obtained for green ballpoint pen inks, i.e., 0.866 by using UV/Vis spectroscopy and FTIR techniques. Black and red ballpoint pen inks showed the highest DPs by using UV/Vis spectroscopy; however, blue ballpoint pen inks got the highest DP by using FTIR spectroscopy. DP has been improved by using chemometric techniques and higher DPs are obtained as compared to visual examination.

Sulfonamides as Optical Chemosensors.

Sulfonamides are auspicious chemosensors which are capable to bind with ionic species through various ways like complexation, charge transfer, proton transfer etc. and produce a detection signal in the form of an optical change either in visible or UV-light and for electronic as well as fluorimetric spectra. Sulfonamides have gained much attention of analytical chemists these days as these are inexpensive, robust, green in nature and some what sensitive and selective to many anionic and cationic species. Due to their promising versatility in sensing properties, these are under great consideration in forensic, environmental, analytical and biochemistry laboratories. This review narrates how sulfonamides are being used to optically sense ionic species.

HIGHLIGHTSOptical sensors are of great importance these days because of their optical detection properties rather using Hi-tech techniques.Optical sensors are economical, robust, selective, sensitive and green in nature.The color change, shifts in electronic spectra or alterations in fluorescence pattern may be attributed by interaction between species to be sensed and Sulfonamides by different mechanism i.e. electron transfer, fluorescence energy transfer, charge transfer, hydrogen bonding, etc.LOD data is a proof of their prodigious efficiency of Sulfonamides as optical sensors.

Fabrication of sensor based on polyvinyl alcohol functionalized tungsten oxide/reduced graphene oxide nanocomposite for electrochemical monitoring of 4-aminophenol.

4-aminophenol (4-AP) is one of the major environmental pollutants which is broadly exploited as drug intermediate in the pharmaceutical formulations. The extensive release of 4-AP in the environment without treatment has become a serious issue that has led several health effects on humans. This work describe the determination of 4-AP through a new chemically modified sensor based on polyvinyl alcohol functionalized tungsten oxide/reduced graphene oxide (PVA/WO3/rGO) nanocomposite. The fabricated nanocomposite was characterized through XRD and HR-TEM to confirm the crystalline structure with average size of 35.9 nm and 2D texture with ultra-fine sheets. The electrochemical characterization of fabricated sensor was carried out by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) to ensure the charge transfer kinetics of modified sensor that revealed high conductivity of PVA/WO3/rGO/GCE. Under optimized conditions e.g. scan rate 80 mV/s, phosphate buffer (pH 6) as supporting electrolyte and potential window from -0.2 to 0.8 V, the prepared sensor showed excellent response for 4-AP. The linear dynamic range of developed method was optimized as 0.003-70 µM. The LOD of fabricated sensor based on PVA/WO3/rGO/GCE for 4-AP was calculated as 0.51 nM. The practical application of PVA/WO3/rGO/GCE was tested in real water and pharmaceutical samples. The fabricated sensor presented here, exhibited exceptional stability and sensitivity than the reported sensors and could be effectively used for the monitoring 4-AP without interferences.

Natural and anthropogenic origin of metallic contamination and health risk assessment: A hydro-geochemical study of Sehwan Sharif, Pakistan.

Heavy metal contamination in groundwater is a serious threat to the environment and therefore its proper monitoring is a matter of great concern these days. In the present research, groundwater samples from Sehwan Sharif district Jamshoro, Pakistan were collected to estimate the concentration of various elements including potentially hazardous metals. Statistical analysis of the collected data based on Pearson co-relation metal clustering and Principal Component Analysis (PCA) divides the elements into three groups; Group I contains As, Cu, Ni, and Cd, Group II contains Mn, Fe, B, and Cr and Group III contains Pb and Zn. The elements Cu, Ni, As, Pb, Cd, and Zn found with higher RSD values demonstrate their anthropogenic origin whereas the lower concentration of Mn, Fe, B, and Cr indicate their natural origin (Tepanosyan et al., 2016). The histograms and box-plots of Mn, Fe, B and Cr were found normally distributed while abnormal for Cu, Ni, Pb, As, Cd and Zn. The HQs of these elements indicate their non-carcinogenic risks. However, results of individual metallic behavior indicate the highest HQ measured for B followed by HQs for Cu, and As. The toxic effects of investigated metal (loid)s calculated using HI were found to be 1.58 for adults and 1.35 for the child which is considered the medium chromic risk and cancer risk. About the toxicity of these heavy metals, their cancer risk was assessed on the levels of Cd, As, and Cr in groundwater. The carcinogenic risk of As was found to be 2.78 × 10-4 and 1.62 × 10-3 for child and adult, respectively. Furthermore, the values of this carcinogenic risk are 2.64 × 10-6 and 1.54 × 10-5 for Cd while 4.24 × 10-3 and 2.48 × 10-2 for Cr in child and adult, respectively. Since cancer risk exceeded the target risk of 1 × 10-4 for As and Cr in adults and children, it can thus be considered 'non-acceptable'. The Geographic Information System (GIS) based maps were prepared using Inverse Distance Weighted (IDW) interpolation which showed the Spatial distribution of all elements throughout Sehwan Sharif from different sources of environment. Spatial maps of elements produced by ArcGIS show the hotspots of potentially hazardous elements such as the highest concentration of Pb, As, Zn, Cu, Ni, and Cd were found in urban areas of Sehwan Sharif district Jamshoro, Pakistan.

Discrimination of Pakistani Fountain Pen Inks by Gas Chromatography-Mass Spectrometry (GC-MS).

In developing countries, the chances of fraud in written documents are comparatively high. Therefore, comparison of fountain pen inks is especially imperative in examination of forensic questioned documents. We have investigated the use of the gas chromatography-mass spectrometry technique in profiling and discrimination of fountain pen ink used in Pakistan for forensic purpose. The main purpose of this study was to discriminate different Pakistani fountain pen inks. The datum for Pakistani inks of fountain pen is not obtainable. In this research study, blue, black, and green colors fountain pen inks commercially used in Pakistan have been extracted from paper using micropunch and then investigated using the gas chromatography-mass spectrometry technique. Gas chromatography-mass spectrometry (GC-MS) was used to differentiate various brands of different colors of fountain pen inks based on their chemical composition. Molecular ion peaks for different components were obtained, and components were identified on the basis of detected ions. Results have been calculated and compared in terms of discriminating power (D.P.). The D.P. for blue, black, and green inks of fountain pen was 1.0 by using the gas chromatography-mass spectrometry technique.

Fe-POM/attapulgite composite materials: Efficient catalysts for plastic pyrolysis.

This article describes the catalytic cracking of low-density polyethylene over attapulgite clay and iron substituted tungstophosphate/attapulgite clay (Fe-POM/attapulgite) composite materials to evaluate their suitability and performance for recycling of plastic waste into liquid fuel. The prepared catalysts enhanced the yield of liquid fuel (hydrocarbons) produced in cracking process. A maximum yield of 82% liquid oil fraction with a negligible amount of coke was obtained for 50% Fe-POM/attapulgite composite. Whereas, only 68% liquid oil fractions with a large amount of solid black residue was produced in case of non-catalytic pyrolysis. Moreover, Fe-POM/attapulgite clay composites showed higher selectivity towards lower hydrocarbons (C5-C12) with aliphatic hydrocarbons as major fractions. These synthesised composite catalysts significantly lowered the pyrolysis temperature from 375°C to 310°C. Hence, recovery of valuable fuel oil from polyethylene using these synthesised catalysts suggested their applicability for energy production from plastic waste at industrial level as well as for effective environment pollution control.

Naked Eye Chemosensing of Anions by Schiff Bases.

Spectacular color change during a chemical reaction is always fascinating. A variety of chemosensors including Schiff bases have been reported for selective as well as sensitive recognition of ions. This review explains the use of Schiff bases as color changing agents in the detection of anions. This magic of colors is attributed to change in the electronic structure of the system during reaction. Schiff base chemosensors are easy to synthesize, inexpensive and can be used for visual sensing of different ions. Development of Schiff base chemosensors is commonly based on the interactions between polar groups of Schiff bases and ionic species and the process of charge transfer, electron transfer and hydrogen bonding between Schiff bases and ionic species cause the color of the resultant to be changed. Therefore, designing of simple Schiff base chemosensors which are capable of selective sensing of different anions has attracted considerable interest. In particular, naked eye sensing through color change is important and useful since it allows sensing of ions through color changes without using any instrumental technique.HighlightsNaked eye sensors are of much interest these days due to their visual detection properties rather employing complex instrumentation.Optical sensors are sensitive, selective, cost effective and robust.The magic of color change is fascinating factor in detection by these sensors.The color change may be attributed by interaction between anion and Schiff base by different mechanism i.e. electron transfer, charge transfer, hydrogen bonding, ICT etc.LOD data is an evidence of their great efficiency.

Metal Ion Detection by Carbon Dots-A Review.

Development of economical, sensitive, selective and robust sensors for metal ion sensing is always fascinating for a chemist because traditional routs for their detection involve complicated instrumentation and critical sample preparation procedures. A large number of metal ion detectors including carbon dots (CDs) have been reported for sensitive and selective detection of metal ions. This review comprehensively explores the use of CDs as metallic cation sensors. CDs are being fabricated from variety of carbon sources by employing various synthetic channels. CDs are proved to be efficient colorimetric and fluorimetric detectors due to surface oxygen moieties which are responsible to co-ordinate with metal ions. Doping of CDs with hetero atom such as N, S, B etc. may further enhance their activity toward metal detection. Therefore, designing of CDs having selective sensing properties with low detection limits has gained significant interest.HighlightsCDs have gained much attention as chemical sensors due to their dynamic features i.e. less toxicity, stability, solubility in various solvents, absorption in UV/Vis. region, fluorescence and tunable physico-chemical properties.These are coast effective, sensitive and selective colorimetric and fluorimetric metal ion sensors.Detection of metal ions by CDs involves different mechanisms such as complexation, aggregation, electron transfer, inner filter effect etc.LOD data is an evidence of their greater efficiency.

Formulation and Characterization of Calcium-Fortified Jelly and Its Proximate Composition and Sensory Analysis.

Calcium is a dynamic mineral. Recent discoveries designate that low intake of calcium generates deficiencies and path to other diseases. Food fortification could play a key role to overcome this problem. To cope with this deficiency problem, jellies were formulated with food-grade calcium salts and chicken eggshell powder. In the present study, three different concentrations of calcium salts, as well as eggshell powder were used to formulate jellies. The results of the sensory evaluation indicated that the two jelly products (A&D) in the current study were suitable for consumers. Results of Atomic Absorption Spectrophotometer revealed Jelly A and jelly D had 151±0.05 ppm and 133±0.06 ppm calcium concentration, respectively. Proximate analysis of Jelly A showed that it has 6.0±0.01% ash, 9.2±0.1% moisture, 0.4±0.01 g crude protein, 82.79±0.001 g crude fiber, and 0.61±0.001 g crude fat, while the jelly D that was made with chicken eggshell powder exhibited 6.0±0.01% ash, 10.1±0.1% moisture, 0.5±0.01 g protein, 84.54±0.01 g crude fiber and 1.61±0.01 g crude fat. Therefore, these two jelly A & D were greatly appreciated among other attributes. In spite of naturally available calcium-rich sources, calcium-fortified jellies can be consumed by individuals who are incapable to take sufficient calcium from their diet.

Carbon dots as naked eye sensors.

Optical sensors are always fascinating for chemists due to their selectivity, sensitivity, robustness and cost-effective nature. Moreover, these sensors provide the facility of onsite detection without employing any instrumental technique. A number of such visual sensors including carbon dots (CDs) have been reported for selective detection of many ionic and molecular species. This review elaborates the utilization of CDs as colorimetric sensors. Carbon dots (CDs) are being synthesized from a large number of natural and synthetic carbon source materials using a variety of methods. CDs can also be tuned chemically by doping, to impart the desired sensing properties. Therefore, the development of CDs with selective sensing properties enables extremely low detection limits and has thus gained substantial attention.

Highly efficient catalytic pyrolysis of polyethylene waste to derive fuel products by novel polyoxometalate/kaolin composites.

We report here alumina-substituted Keggin tungstoborate/kaolin clay composite materials (KAB/kaolin) as polyethylene cracking catalysts. KAB/kaolin composites with varying concentrations of KAB (10-50 wt.%) were synthesized by the wet impregnation method and successfully characterized by Fourier-transform infrared spectroscopy, powder X-ray diffraction, thermo-gravimetric analysis and scanning electron microscopy with energy dispersive X-ray spectroscopy analytical techniques. Use of KAB loaded kaolin composites as the catalyst for low-density polyethylene (LDPE) cracking exhibited a higher percentage of polymer conversion (99%), producing 84 wt.% of fuel oil and negligible amount (˂ 1 wt.%) of solid residue while thermal cracking produced ~22 wt.% residue. Furthermore, gas chromatography-mass spectrometry analysis of oil obtained by non-catalytic cracking exhibited a high selectivity to high molecular weight hydrocarbons (C13-C23) compared to the catalytic cracking where 70 mol.% of gasoline range hydrocarbons (C5-C12) were produced. We propose that higher cracking ability of our prepared catalysts might ensue from both Brønsted and Lewis acid sites (from KAB and kaolin respectively), which enhanced the yield of liquid fuel products and reduced the cracking temperature of LDPE. These findings suggest that the prepared composites were cost-effective and excellent cracking catalysts that could be recommended for highly efficient conversion of waste plastic materials to petrochemicals at an industrial scale.

Forensic Discrimination Potential of Blue, Black, Green, and Red Colored Fountain Pen Inks Commercially Used in Pakistan, by UV/Visible Spectroscopy, Thin Layer Chromatography, and Fourier Transform Infrared Spectroscopy.

Examination and comparison of fountain pen inks are very important in forensic questioned documents examination in developing countries where the chances of fraud are greater in cases of cheques, marriage papers, entry of birth and death, etc. In this study, fountain pen inks of blue, black, green, and red colours that are commercially used in Pakistan have been discriminated by UV-Vis spectroscopy, TLC, and FTIR spectroscopy. We have calculated and compared the results in terms of discriminating power. UV/Visible Spectroscopy of fountain pen inks of different brands showed different composition despite their similar colours. TLC was effectively used to differentiate between the colored components of inks. FTIR results showed that each brand could be distinguished by studying the pattern of their absorption spectra that appeared due to the presence of different functional groups. On the basis of combined results of UV-VIS, TLC, and FTIR, the DP was found from 0.73-0.8 for blue, 0.80-1.0 for black, 0.5-1.0 for green, and 1.0 for red colored fountain pen inks. Overall, this study demonstrated the elevated worth of analysis of fountain pen inks commercially used in Pakistan as the study for fountain pen inks, while not very common, remains an interesting target study.

Synthesis of antibacterial poly(o-chloroaniline)/chromium hybrid composites with enhanced electrical conductivity.

Electrically conductive polyorthochloroaniline/chromium nanocomposites (POC/Cr NCs) were prepared by in situ chemical oxidative polymerization of orthochloroaniline in the presence of Cr nanoparticles (Cr NPs). The load percentage of Cr nanofiller was varied in POC matrix to investigate the effect of Cr nanoparticles on the properties of the nanocomposites. The composition, structure, and morphology of POC and its composites were examined by Scanning electron microscopy, Fourier transform infrared spectroscopy, and UV-visible spectroscopic analysis. The antibacterial potential of POC and its composites was evaluated by the disc diffusion method against Escherichia coli and Bacillus subtilis. The results showed the improved antibacterial potential with the increase in the load percentage of nanofiller. The electrical conductivity of polymer and its composites was measured and correlated with the load percentage. The results showed that electrical conductivity of the composites was enhanced with the increase in load percentage of Cr nanoparticles.

Applications of UV/Vis Spectroscopy in Characterization and Catalytic Activity of Noble Metal Nanoparticles Fabricated in Responsive Polymer Microgels: A Review.

Noble metal nanoparticles loaded smart polymer microgels have gained much attention due to fascinating combination of their properties in a single system. These hybrid systems have been extensively used in biomedicines, photonics, and catalysis. Hybrid microgels are characterized by using various techniques but UV/Vis spectroscopy is an easily available technique for characterization of noble metal nanoparticles loaded microgels. This technique is widely used for determination of size and shape of metal nanoparticles. The tuning of optical properties of noble metal nanoparticles under various stimuli can be studied using UV/Vis spectroscopic method. Time course UV/Vis spectroscopy can also be used to monitor the kinetics of swelling and deswelling of microgels and hybrid microgels. Growth of metal nanoparticles in polymeric network or growth of polymeric network around metal nanoparticle core can be studied by using UV/Vis spectroscopy. This technique can also be used for investigation of various applications of hybrid materials in catalysis, photonics, and sensing. This tutorial review describes the uses of UV/Vis spectroscopy in characterization and catalytic applications of responsive hybrid microgels with respect to recent research progress in this area.

Effect of calcium hydroxide on mechanical strength and biological properties of bioactive glass.

In this manuscript for the first time calcium hydroxide (Ca(OH)2) has been used for preparation of bioactive glass (BG-2) by co-precipitation method and compared with glass prepared using calcium nitrate tetrahydrate Ca(NO3)2·4H2O (BG-1), which is a conventional source of calcium. The new source positively affected physical, biological and mechanical properties of BG-2. The glasses were characterized by Fourier transform infrared (FTIR), X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis/Differential Scanning Calorimetry (TGA-DSC), BET surface area analysis and Knoop hardness. The results showed that BG-2 possessed relatively larger surface properties (100m(2)g(-1) surface area) as compared to BG-1 (78m(2)g(-1)), spherical morphology and crystalline phases (wollastonite and apatite) after sintering at lower than conventional temperature. These properties contribute critical role in both mechanical and biological properties of glasses. The Knoop hardness measurements revealed that BG-2 possessed much better hardness (0.43±0.06GPa at 680°C and 2.16±0.46GPa at 980°C) than BG-1 (0.24±0.01 at 680°C and 0.57±0.07GPA at 980°C) under same conditions. Alamar blue Assay and confocal microscopy revealed that BG-2 exhibited better attachment and proliferation of MG63 cells. Based on the improved biological properties of BG-2 as a consequent of novel calcium source selection, BG-2 is proposed as a bioactive ceramic for hard tissue repair and regeneration applications.

Report: Central nervous system (CNS) toxicity caused by metal poisoning: Brain as a target organ.

People relate the neural disorders with either inheritance or psychological violence but there might be some other reasons responsible for the ailment of people that do not have such a background. The present study explains the chronic effect of heavy toxic metals on nervous system. During experimentation, rabbits used as laboratory animals, were given test metals in their diet. Concentration of metals given to them in the diet was less than their tolerable dietary intake. Behavioral changes were observed during experimentation. Periodic increase in the metal concentration was seen in the blood sample of rabbits. They were slaughtered after a period of eight months of slow poisoning. Histological examination of brain tissues was performed. The brain samples were analyzed by Atomic absorption spectroscopy and Inductively Coupled Plasma Mass Spectrometry to find the retention of heavy metals in mammalian brain. Concentration of lead, mercury and cadmium in the blood samples of occupationally exposed people and patients with neurological disorders at the time of neurosurgery was determined by using the same techniques. During circulation, toxic metals passes through the nerve capillaries to settle down in the brain. Heavy metals cross the blood brain barrier and 'may retain themselves in it. Brain tumors and biopsy samples of patients with neurological disorder were also analyzed to relate neurotoxicity and heavy metal poisoning. Results obtained shows that lead, mercury and cadmium retain themselves in the brain for longer period of time and are one of the causes of neurotoxicity.

Comparison of the photochemistry of organometallic N-heterocyclic carbene and phosphine complexes of manganese.

Time-resolved IR (TRIR) studies on (η(5)-C(5)H(4)Me)Mn(L)(CO) (L = 1,3-diethyl-4,5-dimethylimidazol-2-ylidene, PPh(3)) indicate that the rate of reaction with CO is ca. 10(2) slower for the N-heterocyclic carbene intermediate, which DFT calculations suggest is due to the presence of a strong MnH-C agostic bond. The reactivity of these intermediates in alkane solvents is governed by such interactions rather than solvent coordination to the unsaturated metal centre.

Displacement kinetics of eta(2)-bound furan and 2,3-dihydrofuran from Mn and Cr centers: evidence for the partial dearomatization of the furan ligand.

The displacement of eta(2)-coordinated ligands from the photolytically generated CpMn(CO)(2)L and BzCr(CO)(2)L [Cp = eta(5)-C(5)H(5), Bz = eta(6)-C(6)H(6), L = 2,3-dihydrofuran (DHF), furan] complexes by pyridine has been studied. The displacement reactions span a wide range of time scales from microseconds to hours and were studied using a range of time-resolved IR spectroscopic techniques. The substitution reactions follow a dissociative pathway and the measured activation enthalpies provide an estimate for the strength of the metal-(eta(2)-furan) and metal-(eta(2)-DHF) interactions. In these complexes, the Cr center binds both ligands weaker than the Mn center. There is a approximately 6-10 kcal/mol difference in the binding enthalpies of eta(2)-furan and eta(2)-DHF to both metals suggesting that this difference is the result of a partial loss of resonance energy in the case of the aromatic furan ligand upon interaction with the metal.