Cross-linking Research Articles

Ferrihydrite − Graphene oxide foams as an efficient adsorbent for Arsenic(III) removal from an aqueous solution

We report the synthesis of a new range of ferrihydrite-graphene oxide (FH-GO) foams using chitosan as cross linker, with varying iron content (5 wt%, 10 wt%, and 20 wt% of FH) as highly efficient adsorbents for the removal of arsenic (III) (As(III)) in an aqueous solution. The sonochemical methods were adopted to synthesize various FH-GO foams and were further characterized by XRD, SEM, TEM, FTIR, Raman, and XPS techniques. The synthesized materials were used for the removal of As(III) in both batch and fixed bed absorbent column methods. The adsorption isotherm results showed that the 10 wt% of FH-GO foams demonstrated a superior adsorbent for the As(III) with high adsorption capacities than that of the other two FH-GO foams (5 wt% and 20 wt% of FH). Moreover, 10 wt% of FH-GO foams was also demonstrated to be nearly a complete (>98.4%) removal of As(III) ions at neutral pH 7. The adsorption isotherm fitted very well with the Langmuir model with the highest accuracy data for all the synthesized adsorbent materials. In addition, the fixed bed absorbent column method was also adopted for the removal of As(III) ions in the water sample, which showed >99.2% of removal efficiency. The outstanding adsorption capabilities, along with their easy and low-cost synthesis, make these kinds of adsorbents extremely capable for commercial applications in wastewater treatment and drinking water purification.

A Novel Procedure for Keratoconus/Corneal Ectasia Treating Epithelial Compensation of Higher-Order Aberrations, Topographic Guided Ablation, and Corneal Cross Linking - The CREATE+CXL Protocol.

To present the outcomes of a retrospective study in keratoconus/corneal ectasia patients of treating the higher order aberrations compensated for the corneal epithelium in addition to topographic guided ablation followed by corneal cross linking. Twenty-seven eyes of 14 patients were treated for keratoconus/corneal ectasia utilizing trans-epithelial topographic guided ablation photorefractive keratectomy (PRK) for treatment of corneal higher order aberrations and lower order astigmatism followed immediately by 15-minute cross linking were examined retrospectively. Six-month results were analyzed via measurement of vision, refraction, residual higher-order aberrations (HOAs), residual lower-order and higher-order aberrations, as well as for loss or gains of lines of best corrected visual acuity. All eyes save one had reduction in K1, K2, K Max, and K Mean. All eyes had reduction in manifest astigmatism, Contoura measured astigmatism, 57% reduction of higher-order aberrations (HOA), and 53% reduction of higher-order aberrations grouped with lower-order aberrations (Grouped). Nearly all (96.3%) eyes achieved 20/40 vision or better, 20 eyes had 1-7 lines gained of vision, and no eyes had any loss of lines of vision. Use of the CREATE+CXL protocol combined with 15-minute corneal cross linking results in a significant increase in HOA reduction, as well as a significant improvement in corrected distance visual acuity over past procedures.

Electrospun Nanofibers including Organic/Inorganic Nanohybrids: Polystyrene- and Clay-Based Architectures in Immunosensor Preparation for Serum Amyloid A.

Diagnostic techniques based on biomolecules have application potential that can be realized in many fields, such as disease diagnosis, bioprocess imaging, food/beverage industries, and environmental pollutant imaging. Successful surface immobilization of biomolecules is critical to increasing the stabilization, sensitivity, and selectivity of biomolecules used in bioassay systems. Nanofibers are good candidates for the immobilization of biomolecules owing to many advantages such as morphology and pore size. In this study, montmorillonite (MMT) clay is modified with poly(amidoamine) (PAMAM) generation 3 (PAMAMG3) and added to polystyrene (PS) solutions, following which PS/MMT-PAMAMG3 nanofibers are obtained using the electrospinning method. The nanofibers are obtained by testing PS% (wt%) and MMT-PAMAMG3% (wt%) ratios and characterized with scanning electron microscopy. Antiserum amyloid A antibody (Anti-SAA) is then conjugated to the nanofibers on the electrode surface via covalent bonds using a zero-length cross linker. Finally, the obtained selective surface is used for electrochemical determination of serum amyloid A (SAA) levels. The linear range of PS/MMT-PAMAM/Anti-SAA is between 1 and 200 ng/mL SAA, and the detection limit is 0.57 ng/mL SAA. The applicability of PS/MMT-PAMAMG3/Anti-SAA is investigated by taking measurements in synthetic saliva and serum both containing SAA.

Hybridization of Solar PV Configurations for Maximum Power Extraction Under Partial Shading Conditions

ABSTRACT In the current era, the solar-based energy demand is exponentially progressing, because of its streamlinedness towards the environment. However, an optimized version of the photo voltaic (PV) configuration is required even though there are conventional PV configurations. In the purview of an optimized PV system, vital factors that affect the performance of the PV system are the type of configuration, partial shaded conditions, the efficiency of the PV array and power conditioning units. In this paper, an optimized configuration of a PV array under different partial shaded conditions is taken as a focal point. Therefore, a hybrid configuration of the PV system has been designed for extracting maximum power, such as Bridge Link with Triple Tied Cross Link (BL-TTCL), Honey Comb with Triple Tied Cross-Link (HC-TTCL), etc. The proposed hybrid configurations are simulated in MATLAB/SIMULINK software. The performance analysis of proposed hybrid PV configurations was analysed with the conventional configurations in terms of global maximum power point, local maximum power point, open circuit voltage, short circuit current, mismatch losses, voltage and current at maximum power point and efficiency. The outcome of both conventional and hybrid PV configurations reveals that, more cross ties result in optimized PV configurations under various partial shaded conditions due to more bypass paths, but there should be trade-off/balance between capex and technical behaviour. Therefore, the hybrid configurations balance cross ties and behaviour under various partial shaded conditions.

Using a Smartphone-Based Colorimetric Device with Molecularly Imprinted Polymer for the Quantification of Tartrazine in Soda Drinks.

The present study reports the development and application of a rapid, low-cost in-situ method for the quantification of tartrazine in carbonated beverages using a smartphone-based colorimetric device with molecularly imprinted polymer (MIP). The MIP was synthesized using the free radical precipitation method with acrylamide (AC) as the functional monomer, N,N'-methylenebisacrylamide (NMBA) as the cross linker, and potassium persulfate (KPS) as radical initiator. The smartphone (RadesPhone)-operated rapid analysis device proposed in this study has dimensions of 10 × 10 × 15 cm and is illuminated internally by light emitting diode (LED) lights with intensity of 170 lux. The analytical methodology involved the use of a smartphone camera to capture images of MIP at various tartrazine concentrations, and the subsequent application of the Image-J software to calculate the red, green, blue (RGB) color values and hue, saturation, value (HSV) values from these images. A multivariate calibration analysis of tartrazine in the range of 0 to 30 mg/L was performed, and the optimum working range was determined to be 0 to 20 mg/L using five principal components and a limit of detection (LOD) of 1.2 mg/L was obtained. Repeatability analysis of tartrazine solutions with concentrations of 4, 8, and 15 mg/L (n = 10) showed a coefficient of variation (% RSD) of less than 6%. The proposed technique was applied to the analysis of five Peruvian soda drinks and the results were compared with the UHPLC reference method. The proposed technique showed a relative error between 6% and 16% and % RSD lower than 6.3%. The results of this study demonstrate that the smartphone-based device is a suitable analytical tool that offers an on-site, cost-effective, and rapid alternative for the quantification of tartrazine in soda drinks. This color analysis device can be used in other molecularly imprinted polymer systems and offers a wide range of possibilities for the detection and quantification of compounds in various industrial and environmental matrices that generate a color change in the MIP matrix.

Evaluating the Effect of Sumac Extract on Dentine Micro-Hardness during pH Cycling.

Although sumac extract (SE) is reported as a collagen cross linker, the available data regarding its effect on the dentine micro-hardness is quite sparse. Therefore, the aim of this study includes evaluating the effect of different concentrations of SE on dentine micro-hardness comparing to grape seed extract (GSE). In this experimental study, the GSE was purchased from available market and convert to 5% solution. Meanwhile the 5, 10, and 20% of SE solutions were prepared experimentally. The base line micro-hardness of 60 samples (30 premolars divided to buccal and lingual segments) was recorded triplicate for each specimen and they were randomly divided into 5 groups (four abovementioned experimental solutions and de-ionized water as negative control). For 35 consecutive days, each sample was twice pH cycled and treated by solutions. Ultimately, the final micro-hardness was recorded triplicate again for each sample and the numerical data was compared with each other using one-way ANOVA and Tukey HSD Post Hoc tests (α=0.05). The meanSD values of micro-hardness for the groups was recorded as 54.45 13.4, 65.6518.5, 39.572.26, 41.131.66 and 43.794.96 at base line and 10.40.99, 11.85 0.75, 10.161.84, 8.481.16 and 6.311.01 at final stage for control, GSE 5%, SE 5%, SE 10% and SE 20% respectively. There was no significant difference among the micro-hardness of the groups before treatment (p= 0.369). However, after experimental treatment, there was significant difference between the groups (p= 0.024) while in pairwise comparison just two groups (GSE 5% and SE 20%) had significant difference with each other (p= 0.017). The efficacy of SE was reversely related to its concentration. Moreover, neither GSE nor SE had significant effect on dentine micro-hardness after 35 day pH cycling.

Influence of chemical modification approaches on physicochemical and structural properties of dietary fiber from oat

The effects of carboxymethylation (CM), hydroxypropylation (HP), and cross-linking (CL) on the physicochemical, thermal, and microstructural properties of oat dietary fiber (ODF) were investigated. ODF extracted from defatted oat flour had 66.14% total dietary fiber, 3.42% protein, 5.15% ash, and 1.86% starch. Chemical modifications (CM, HP, CL) significantly improved the SDF but decreased the IDF content of ODF. Results displayed that all the chemical treatments significantly (p < 0.05) improved the swelling capacity, oil absorption capacity, and water absorption capacity of ODF with carboxymethylation being the highly influential. The CM significantly increased the solubility (7.15%), while CL (4.78%) and HP (4.17%) significantly (p < 0.05) decreased the solubility of ODF. The color evaluation showed a decrease in the L* value of ODF after all three modifications, resulting in an increase in the brown color of ODF. XRD results demonstrated an increase in the crystallinity value of ODF after these modifications (19.23–28.94%). DSC results reflected an increase in decomposition/peak temperature of cross-linked ODF showing enhanced thermal stability of such type of modified DF. The changes in physicochemical, microstructural, and thermal properties of ODF after chemical modifications could be attributed to the variations in chemical composition and structure as demonstrated by XRD, FTIR, and SEM analysis.

Alkylated chitosan nanomaterials for enhanced antimicrobial activity and delivery of fusidic acid: Preparation and preliminary in vitro investigation

AbstractNanomaterials manufactured of amphiphilically‐altered polysaccharides have sparked a great deal of interest due to their capability to elevate drug transport across the skin. The study presents the fabrication of alkylated chitosan through 2‐tert‐butoxymethyloxirane alteration (alkylation degree 29.7%), that was typified by spectroscopic, chromatographic, and thermal analysis approaches before being constructed into nanomaterials for the analysis of their capability in governing fusidic acid diffusion percutaneously. The nanomaterials were constructed via the ionic interaction of positively charged chitosan and negatively charged cross linker sodium tripolyphosphate, with a loading degree of fusidic acid of ca. 20% reported. Fusidic acid release was slower in nanomaterials constructed of alkylated chitosan than in neat chitosan. Under application‐relevant conditions, in vitro incubation with HaCaT cells exhibited insignificant toxicity. Using Franz diffusion cells, the alkylated chitosan nanomaterials induced fusidic acid to infiltrate the Strat‐M® membrane at a 2‐fold greater rate than the neat chitosan nanomaterials. Based on the agar diffusion test, fusidic acid was shown to have better antimicrobial activity when loaded into alkylated chitosan nanomaterials than when loaded into neat chitosan nanomaterials. Ultimately, the in vitro results revealed that alkylated chitosan nanomaterials offer a great deal of potential for percutaneous delivery, which merits greater analysis.

Type 2 diabetes alters the viscoelastic behavior and macromolecular composition of vertebra

Type 2 diabetes (T2D) affects the functional behavior of vertebra bone by altering its structural and mechanical properties. The vertebral bones are responsible to carry the body weight and it remains under prolonged constant load which results to viscoelastic deformation. The effect of T2D on the viscoelastic behavior of vertebral bone is not well explored yet. In this study, the effects of T2D on the creep and stress relaxation behavior of vertebral bone are investigated. Also, this study established a correlation between T2D associated alteration in macromolecular structure and viscoelastic behavior of vertebra. In this study T2D female rat SD model was used. The obtained results demonstrated a significant reduction in the amount of creep strain (p ≤ 0.05) and stress relaxation (p ≤ 0.01) in T2D specimens than the control. Also, the creep rate was found significantly lower in T2D specimens. On the other hand, molecular structural parameters such as mineral-to-matrix ratio (control vs T2D: 2.93 ± 0.78 vs 3.72 ± 0.53; p = 0.02), and non-enzymatic cross link ratio (NE-xL) (control vs T2D: 1.53 ± 0.07 vs 3.84 ± 0.20; p = 0.01) were found significantly altered in T2D specimens. Pearson linear correlation tests show a significant correlation; between creep rate and NE-xL (r = −0.94, p < 0.01), and between stress relaxation and NE-xL (r = −0.946, p < 0.01). Overall this study explored the understanding about the disease associated alteration in viscoelastic response of vertebra and its correlation with macromolecular composition which can help to understand the disease related impaired functioning of the vertebrae body.

Development and validation of a liquid chromatography-triple quadrupole mass spectrometry method for the determination of isopeptide ε-(γ-glutamyl) lysine in human urine as biomarker for transglutaminase 2 cross-linked proteins

Determination of the levels of protein cross-linking catalysed by the activity of transglutaminase 2 in various disease states has remained a significant challenge. The ability to quantify the isopeptide ε-(γ-glutamyl) lysine, which can form as a heterogeneous bond within or between proteins has significant analytical and clinical potential as a biomarker in biofluids such as human urine. Increased transglutaminase 2 activity is associated with a number of diseases, such as fibrosis. Previously published methods have been based on classical amino acid analysis, however they require a complex multi-enzyme digestion in order to achieve complete protein digestion, whilst leaving the isopeptide cross link intact. These methods require high levels of enzymes, which contaminate the analysis and alter the dynamics of digestion. The amino acid analysis detection also lacked selectivity, especially where the levels of crosslink are expected to be low relative to the background protein levels. We have systematically addressed these challenges, by optimising the precipitation of the protein in urine, the use of innovative immobilised enzyme technology, which allows for efficient digestion without enzyme contamination and LC-MS/MS detection based on multiple reaction monitoring. This method was validated for its analytical performance characteristics, showing the method has a sensitivity of 0.1 ng/mL of ε-(γ-glutamyl) lysine in human urine with precision of less than 20% CV, and is selective as no interferences were observed that may adversely affect the analysis. As such this approach represents a significant advance in the ability to detect and quantify ε-(γ-glutamyl) lysine.

The relationship between elastin cross linking and alveolar wall rupture in human pulmonary emphysema.

To better define the role of mechanical forces in pulmonary emphysema, we employed methods recently developed in our laboratory to identify microscopic level relationships between airspace size and elastin-specific desmosine and isodesmosine (DID) cross links in normal and emphysematous human lungs. Free DID in wet tissue (a biomarker for elastin degradation) and total DID in formalin-fixed, paraffin-embedded (FFPE) tissue sections were measured using liquid chromatography-tandem mass spectrometry and correlated with alveolar diameter, as determined by the mean linear intercept (MLI) method. There was a positive correlation between free lung DID and MLI (P < 0.0001) in formalin-fixed lungs, and elastin breakdown was greatly accelerated when airspace diameter exceeded 400 µm. In FFPE tissue, DID density was markedly increased beyond 300 µm (P < 0.0001) and leveled off around 400 µm. Elastic fiber surface area similarly peaked at around 400 µm, but to a much lesser extent than DID density, indicating that elastin cross linking is markedly increased in response to early changes in airspace size. These findings support the hypothesis that airspace enlargement is an emergent phenomenon in which initial proliferation of DID cross links to counteract alveolar wall distention is followed by a phase transition involving rapid acceleration of elastin breakdown, alveolar wall rupture, and progression to an active disease state that is less amenable to therapeutic intervention.NEW & NOTEWORTHY The current findings support the hypothesis that airspace enlargement is an emergent phenomenon in which initial proliferation of DID cross links to counteract alveolar wall distention is followed by a phase transition involving rapid acceleration of elastin breakdown, alveolar wall rupture, and progression to an active disease state that is less amenable to therapeutic intervention.

Novel Technique to Improve the Efficacy of Corneal Cross Linking in Cases of Post LASIK Ectasia.

The aim of the present study was to validate the use of a novel technique that can improve the efficacy of corneal cross-linking (CXL) in cases with post LASIK ectasia. This is a retrospective, comparative study that was conducted on patients who sought medical advice at Ain Shams University Hospitals and Maadi Eye Subspeciality Center, Cairo, Egypt. It included two groups of patients with post LASIK ectasia. Group 1 included patients who performed our proposed protocol (topo-guided PRK, followed by customized phototherapeutic keratectomy "PTK" to transmit the laser treatment to the corneal stroma, then CXL). For group 2, accelerated CXL was performed. Subjective refraction and relevant topographic/tomographic parameters (Sirius topographer) compared between the two groups. Recorded follow-ups included the 2 to 3-month follow-up visit and the last visit (mean ± SD of 17.2 months ± 10.2). Patients of group 1 (22 eyes of 22 patients) experienced significant improvements in most of the evaluated parameters at the 2- to 3-month follow-up visit and showed stability of the ectatic condition at the last follow-up visit, whereas patients of group 2 (10 eyes of 10 patients) showed stability of their ectatic condition at the 2- to 3-month follow-up visit, and one patient developed ectasia progression at the last follow-up visit. The present study validates the use of our novel protocol in cases having post LASIK ectasia with proven efficacy, safety, and stability, providing regularization for the corneal surface while simultaneously avoiding the unnecessary loss of cross-linking effect within the LASIK flap that no longer shares in the corneal biomechanical strength.

Synthesis of molecularly imprinted polymer as a nanosorbent for dispersive magnetic micro solid-phase extraction and determination of valsartan in biological samples by UV–Vis Spectrophotometry: Isotherm, kinetics, and thermodynamic studies

A magnetic molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization utilizing Fe3O4@SiO2-MPS as a magnetic core, itaconic acid as a functional monomer, azobisisobutyronitrile as an initiator, and ethylene glycol dimethacrylate as a cross linker. It was then applied as a nanosorbent for dispersive magnetic micro solid phase extraction (DM-µ-SPE) and determination of valsartan in biological fluids. The morphology and structure of magnetic MIP were characterized by Fourier-transform infrared spectroscopy, Field Emission Scanning electron microscopy, Vibrating sample magnetometer, Energy dispersive x-ray analysis, and Thermogravimetric analysis. The influence of operation conditions on sorption, such as pH (4–10), contact time (10–25 min), initial concentration (1–30 mg L−1), and temperature (25–40 °C) was investigated. After the extraction step, the valsartan concentration was determined by UV–Vis spectrophotometer at 253 nm. The isotherm and kinetic of valsartan sorption were best fitted by the Langmuir model (R2 = 0.987) and the Pseudo second-order kinetic model (R2 = 0.971), respectively. The maximum monolayer sorption capacity for magnetic MIP was obtained to be 4.56 mg g−1. The analytical approach demonstrated favorable figures of merit, with a linear dynamic range of 10–100 µg L−1, a low detection limit of 0.56 µg L−1, and an acceptable preconcentration factor of 5 acquired in optimum conditions. The recoveries of the suggested technique at three spiked levels of analysis were in the range of 101 %–102 %. Valsartan was extracted from various real samples (urine and human blood plasma samples) utilizing the proposed magnetic nanosorbent, and the results exhibited that magnetic MIP was favorable for extraction and measurement of trace amounts of valsartan in biological samples.

Moisture Content and Mechanical Properties of Bio-Waste Pellets for Fuel and/or Water Remediation Applications

The current research is focused on the mutual comparison (mechanical properties, response to humidity) of agro-waste composite materials. The purpose of this work is directed at the valorization of agro-waste biomass products and to investigate their mechanical stability for transport or other applications (in dry and wet states). Three different types of agro-waste (oat hull (Oh), torrefied wheat straw (S), and spent coffee grounds (SCG)) were blended with kaolinite (K) and chitosan (CHT) at variable weight ratios to yield ternary composites. Mechanical properties were represented by measuring hardness (in compression mode) and elastic modulus (under tension mode). Young’s (elastic) modulus was measured both for dried and hydrated samples. The pelletized materials were prepared in two forms: crosslinked (CL) with epichlorohydrin and non-crosslinked (NCL). The hardness of the Oh pellets was poor (75 N) and decreased by four times with greater agro-waste content, while crosslinking affected the hardness only slightly. S pellets had the highest level of hardness at 40% agro-waste content (160 N), with a concomitant decrease to 120 N upon crosslinking. SCG pellets had the least change in hardness for both CL and NCL specimens (105–120 N). The trends of Young’s modulus were similar to hardness. Hydration caused the elastic modulus to decrease ca. 100-fold. In general, S and SCG composites exhibit the greatest hardness and Young’s modulus compared to Oh composites (CL or NCL) in their dry state.

Residual motion of cortical versus pedicle screw constructs after decompression, interbody fusion and cross-link augmentation

PurposeTo compare the residual range of motion (ROM) of cortical screw (CS) versus pedicle screw (PS) instrumented lumbar segments and the additional effect of transforaminal interbody fusion (TLIF) and cross-link (CL) augmentation.MethodsROM of thirty-five human cadaver lumbar segments in flexion/extension (FE), lateral bending (LB), lateral shear (LS), anterior shear (AS), axial rotation (AR), and axial compression (AC) was recorded. After instrumenting the segments with PS (n = 17) and CS (n = 18), ROM in relation to the uninstrumented segments was evaluated without and with CL augmentation before and after decompression and TLIF.ResultsCS and PS instrumentations both significantly reduced ROM in all loading directions, except AC. In undecompressed segments, a significantly lower relative (and absolute) reduction of motion in LB was found with CS 61% (absolute 3.3°) as compared to PS 71% (4.0°; p = 0.048). FE, AR, AS, LS, and AC values were similar between CS and PS instrumented segments without interbody fusion. After decompression and TLIF insertion, no difference between CS and PS was found in LB and neither in any other loading direction. CL augmentation did not diminish differences in LB between CS and PS in the undecompressed state but led to an additional small AR reduction of 11% (0.15°) in CS and 7% (0.05°) in PS instrumentation.ConclusionSimilar residual motion is found with CS and PS instrumentation, except of slightly, but significantly inferior reduction of ROM in LB with CS. Differences between CS and PS in diminish with TLIF but not with CL augmentation.

Selective fluorescent probe for sensitive determination of bisphenol A based on molecularly imprinted polymers decorated carbon dots derived from citric acid and ethylenediamine

Bisphenol A (BPA) is an endocrine disrupting chemical and poses a grave threat to the human health. Herein, a fluorescent probe constructed with molecularly imprinted polymers decorated carbon dots (CDs@MIPs) was proposed for determination of BPA with high selectivity. The CDs@MIPs were constructed using BPA, 4-vinylpyridine and ethylene glycol dimethacrylate as template, functional monomer and cross linker, respectively. The obtained fluorescent probe not only owned a highly selective recognition function derived from MIPs but also displayed an excellent sensitivity for sensing BPA stemmed from CDs. The fluorescence intensity of CDs@MIPs was varied before and after the removal of BPA templates. The fluorescent decrease fraction of the fluorescent probe demonstrates a nice linearity in BPA concentration range of 10–2000 nM (r2 = 0.9998) and the detection limit is as low as 1.5 nM. The fluorescent probe was triumphantly utilized to sense the level of BPA in real aqueous and plastic samples with good results. Moreover, the fluorescent probe offered a wonderful means for fast identification and sensitive detection of BPA from environmental aqueous samples.

Novel Double Tied Cross Link with Reduced Cross Cables for Maximum Power Extraction under Uniform and Non-Uniform Shading Conditions

Partially shaded panels lead to the creation of troughs in the power generation PV curve, from its optimal potential. Researchers have focally went through for findings in the optimal Photo Voltaic (PV) configuration namely Series (S), Parallel (P), Series–Parallel (SP), Bridge Link (BL), Honey Comb (HC), Total Cross Tie (TCT), Triple Tied Cross Link (TTCL), and Hybrid Configurations. In this paper, a Novel Double Tied Cross Link (DTCL)-based PV panel configuration is proposed. The superiority of the proposed DTCL configuration is that the number of local maximum power points (LMPP) is reduced in certain partial shaded conditions and optimized cost also possible, as the number of cross-links has been reduced, compared to conventional configurations. The maximum power generation superiority of TCT and TTCL has been realized with the proposed novel configuration of Double Tied Cross Link. Using MATLAB/Simulink, different patterns of possible shadings have been created as a replica of real-time partial shadings. Analysis of the proposed DTCL configuration has been implemented along with the conventional configurations in MATLAB simulation. The technical parameters, such as open circuit voltage, short circuit current, maximum voltage, maximum current, fill factor, mismatch losses, and efficiency, are considered for analyzing the proposed DTCL photo voltaic configuration. Besides, this article also presents a novel DTCL PV configuration which reveals cross-cable savings, maximum power attainment, and economically feasible, as usage of cross cables is less, without much compromising on power generation.

A biomimetic study of aliphatic and aromatic dicarboxylic acids engineered β-CD targeted for intestinal maladies

Presently, biomaterials are extensively used for biomedical applications such as drug delivery. In-vitro simulation studies provide preliminary insights about the molecular interaction of synthesized biomaterials in the body. In the present work, β-Cyclodextrin materials with succinic acid and phthalic acid as cross linkers exhibited sustained release of the drug, curcumin, during biomimetic screening studies. Fourier transform infrared spectroscopy(FTIR), 1H-NMR,particle size analysis, scanning electron microscopy (SEM) and X-ray diffraction (XRD) studies were used for the physiochemical characterization of the polymers. The effect of aliphatic and aromatic di-carboxylic acids crosslinking agents on binding of curcumin was studied experimentally and computationally. In-vitro release studies were carried out under simulated gastro-intestinal conditions (pH 1.2 HCl buffer for gastric environment, phosphate buffer of pH 6.8 for duodenum and phosphate buffer of pH 7.4 for intestinal conditions at 37 °C). Sustained drug release was also verified by time dependent anti-inflammatory and anti-cathepsin studies. The results indicated these synthesized biomaterials can be used for intestinal delivery of curcumin.

Preparation, characterization and release studies of naproxen-loaded microspheres from natural gums

Background: Use of biodegradable natural materials as pharmaceutical excipients is increasing. In this study, Naproxen loaded microbeads were produced, using natural gums obtained from Cedrela odorata and Irvingia gabonensisObjective: Aim is to evaluate physicochemical properties of the gums and determining release properties of the formulations.Materials and Methods: Cedrela gum (CG) and Irvingia gum (IG) were extracted from Cedrela odorata and Irvingia gabonensis respectively, and characterized by viscosity, density and pH measurements. Naproxen microbeads were formulated (Formulation A2 to A9) with the gums and sodium alginate using ionotropic gelation method. Cross linkers (CaCl2 or Al2[SO4]3) were used at different curing times. Scanning electron microscopy (SEM), photomicrographs, entrapment efficiency and release profiles of the formulations were determined.Results: Physicochemical property tests showed that the gums possess good flow, viscosity and they presented with acidic pH. There was no interaction between FT-IR spectra of the gums and naproxen. SEM revealed microbeads to be almost spherical, having slightly rough surfaces. Microbeads from Formulation A6 had the largest particle size (1500±163.2 μm) while Formulation A9 possessed the smallest particle size A9 (491.6±191.7 μm). All the formulations gave high entrapment efficiency (80 – 96%); microbeads containing IG (Batch A6 – A9) had higher values than those formulated with CG gum (Batch A2 – A5) (p &gt; 0.05). Batch A6 (containing IG with CaCl2 at curing time of 15 minutes) gave the highest drug release (p &lt; 0.05).Conclusion: Gums obtained from Cedrela odorata and Irvingia gabonensis possessed good physicochemical properties and produced microbeads suitable for the controlled release of Naproxen. Formulations containing Irvingia gum showed higher drug release and better entrapment.

Cross-linking, carboxymethylation and hydroxypropylation treatment to sorghum dietary fiber: Effect on physicochemical, micro structural and thermal properties

The effect of cross-linking (CL), carboxymethylation (CM), and hydroxypropylation (HP) on the physicochemical, micro-structural, and thermal properties of sorghum dietary fiber (SODF) was studied. Results reflected that all three modifications significantly (p < 0.05) increased the water absorption capacity, swelling capacity, oil absorption capacity, and soluble dietary fiber content of SODF with CM being the most effective treatment. The CM significantly (p < 0.05) improved the solubility (9.9 %), whereas CL (4.65 %) and HP (2.79 %) significantly reduced the solubility of native SODF. The color analysis reflected the decrease in L* value after all modifications, indicating an increase in brown color of SODF. XRD analysis reflected an increase in crystallinity value (14.47 to 17.94 %) of SODF after modifications, resulting in increased thermal stability of modified SODF. The DSC results revealed the increased decomposition temperature of cross-linked and hydroxypropylated dietary fiber showing improved thermal stability of these types of modified fibers. The changes in thermal, physicochemical, and microstructural properties of SODF after modification could be ascribed to the changes in structure and chemical composition as reflected from SEM, XRD, and FTIR analysis.