Retention of Ciprofloxacin and Carbamazepine from Aqueous Solutions Using Chitosan-Based Cryostructured Composites

Water pollution is becoming a great concern at the global level due to highly polluted effluents, which are charged year by year with increasing amounts of organic residues, dyes, pharmaceuticals and heavy metals. For some of these pollutants, the industrial treatment of wastewater is still relevant. Yet, in some cases, such as pharmaceuticals, specific treatment schemes are urgently required. Therefore, the present study describes the synthesis and evaluation of promising cryostructured composite adsorbents based on chitosan containing native minerals and two types of reinforcement materials (functionalized kaolin and synthetic silicate microparticles). The targeted pharmaceuticals refer to the ciprofloxacin (CIP) antibiotic and the carbamazepine (CBZ) drug, for which the current water treatment process seem to be less efficient, making them appear in exceedingly high concentrations, even in tap water. The study reveals first the progress made for improving the mechanical stability and resilience to water disintegration, as a function of pH, of chitosan-based cryostructures. Further on, a retention study shows that both pharmaceuticals are retained with high efficiency (up to 85.94% CIP and 86.38% CBZ) from diluted aqueous solutions.

Chitosan-Based Beads Incorporating Inorganic-Organic Composites for Copper Ion Retention in Aqueous Solutions

In recent years, there has been a challenging interest in developing low-cost biopolymeric materials for wastewater treatment. In the present work, new adsorbents, based on different types of chitosan (commercial, commercial chitin-derived chitosan and chitosan synthesized from shrimp shell waste) and inorganic-organic composites have been evaluated for copper ions removal. The efficacy of the synthesis of chitosan-based composite beads has been determined by studying various characteristics using several techniques, including FTIR spectroscopy, X-ray diffraction, porosimetry (N2 adsorption), and scanning electron microscopy (SEM). Adsorption kinetics was performed using different adsorption models to determine the adsorption behavior of the materials in the aqueous media. For all composite beads, regardless of the type of chitosan used, good capacity to remove copper ions from simulated waters was observed (up to 17 mg/g), which proves that the new materials hold potential for heavy metal retention. However, the adsorption efficiency was influenced by the type of chitosan used. Thus, for the series where commercial chitosan (CC) was used, the removal efficiency was approximately 29%; for the series with chitosan obtained from commercial chitin (SC), the removal efficiency was approximately 34%; for the series with chitosan enriched with CaCO3 (SH), the removal efficiency was approximately 52%.

Electrospun/3D-Printed Bicomponent Scaffold Co-Loaded with a Prodrug and a Drug with Antibacterial and Immunomodulatory Properties

This work reports the construction of a bicomponent scaffold co-loaded with both a prodrug and a drug (BiFp@Ht) as an efficient platform for wound dressing, by combining the electrospinning and 3D-printing technologies. The outer component consisted of a chitosan/polyethylene oxide-electrospun membrane loaded with the indomethacin-polyethylene glycol-indomethacin prodrug (Fp) and served as a support for printing the inner component, a gelatin methacryloyl/sodium alginate hydrogel loaded with tetracycline hydrochloride (Ht). The different architectural characteristics of the electrospun and 3D-printed layers were very well highlighted in a morphological analysis performed by Scanning Electron Microscopy (SEM). In vitro release profile studies demonstrated that both Fp and Ht layers were capable to release the loaded therapeutics in a controlled and sustained manner. According to a quantitative in vitro biological assessment, the bicomponent BiFp@Ht scaffold showed a good biocompatibility and no cytotoxic effect on HeLa cell cultures, while the highest proliferation level was noted in the case of HeLa cells seeded onto an Fp nanofibrous membrane. Furthermore, the BiFp@Ht scaffold presented an excellent antimicrobial activity against the E. coli and S. aureus bacterial strains, along with promising anti-inflammatory and proangiogenic activities, proving its potential to be used for wound dressing.

Introducing Semi-Interpenetrating Networks of Chitosan and Ammonium-Quaternary Polymers for the Effective Removal of Waterborne Pathogens from Wastewaters

The present work aims to study the influence of ammonium-quaternary monomers and chitosan, obtained from different sources, upon the effect of semi-interpenetrating polymer network (semi-IPN) hydrogels upon the removal of waterborne pathogens and bacteria from wastewater. To this end, the study was focused on using vinyl benzyl trimethylammonium chloride (VBTAC), a water-soluble monomer with known antibacterial properties, and mineral-enriched chitosan extracted from shrimp shells, to prepare the semi-IPNs. By using chitosan, which still contains the native minerals (mainly calcium carbonate), the study intends to justify that the stability and efficiency of the semi-IPN bactericidal devices can be modified and better improved. The new semi-IPNs were characterized for composition, thermal stability and morphology using well-known methods. Swelling degree (SD%) and the bactericidal effect assessed using molecular methods revealed that hydrogels made of chitosan derived from shrimp shell demonstrated the most competitive and promising potential for wastewater (WW) treatment.

A Top-Down Procedure for Synthesizing Calcium Carbonate-Enriched Chitosan from Shrimp Shell Wastes

Chitosan is used in medicine, pharmaceuticals, cosmetics, agriculture, water treatment, and food due to its superior biocompatibility and biodegradability. Nevertheless, the complex and relatively expensive extraction costs hamper its exploitation and, implicitly, the recycling of marine waste, the most abundant source of chitosan. In the spirit of developing environmental-friendly and cost-effective procedures, the present study describes one method worth consideration to deliver calcium-carbonate-enriched chitosan from shrimp shell waste, which proposes to maintain the native minerals in the structure of chitin in order to improve the thermal stability and processability of chitosan. Therefore, a synthesis protocol was developed starting from an optimized deacetylation procedure using commercial chitin. The ultimate chitosan product from shrimp shells, containing native calcium carbonate, was further compared to commercial chitosan and chitosan synthesized from commercial chitin. Finally, the collected data during the study pointed out that the prospected method succeeded in delivering calcium-carbonate-enriched chitosan with high deacetylation degree (approximately 75%), low molecular weight (Mn ≈ 10.000 g/ mol), a crystallinity above 59 calculated in the (020) plane, high thermal stability (maximum decomposition temperature over 300 °C), and constant viscosity on a wide range of share rates (quasi-Newtonian behavior), becoming a viable candidate for future chitosan-based materials that can expand the application horizon.

Mitigating Antibiotic Resistance Genes in Wastewater by Sequential Treatment with Novel Nanomaterials

Wastewater (WW) has been widely recognized as the major sink of a variety of emerging pathogens (EPs), antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs), which may disseminate and impact wider environments. Improving and maximizing WW treatment efficiency to remove these microbial hazards is fundamentally imperative. Despite a variety of physical, biological and chemical treatment technologies, the efficiency of ARG removal is still far from satisfactory. Within our recently accomplished M-ERA.NET project, novel functionalized nanomaterials, i.e., molecularly imprinted polymer (MIP) films and quaternary ammonium salt (QAS) modified kaolin microparticles, were developed and demonstrated to have significant EP removal effectiveness on both Gram-positive bacteria (GPB) and Gram-negative bacteria (GNB) from WW. As a continuation of this project, we took the further step of exploring their ARG mitigation potential. Strikingly, by applying MIP and QAS functionalized kaolin microparticles in tandem, the ARGs prevalent in wastewater treatment plants (WWTPs), e.g., blaCTXM, ermB and qnrS, can be drastically reduced by 2.7, 3.9 and 4.9 log (copies/100 mL), respectively, whereas sul1, tetO and mecA can be eliminated below their detection limits. In terms of class I integron-integrase I (intI1), a mobile genetic element (MGE) for horizontal gene transfer (HGT), 4.3 log (copies/100 mL) reduction was achieved. Overall, the novel nanomaterials exhibit outstanding performance on attenuating ARGs in WW, being superior to their control references. This finding provides additional merit to the application of developed nanomaterials for WW purification towards ARG elimination, in addition to the proven bactericidal effect.

Poly(β-cyclodextrin)-Activated Carbon Gel Composites for Removal of Pesticides from Water

Pesticides are widely used in agriculture to increase and protect crop production. A substantial percentage of the active substances applied is retained in the soil or flows into water courses, constituting a very relevant environmental problem. There are several methods for the removal of pesticides from soils and water; however, their efficiency is still a challenge. An alternative to current methods relies on the use of effective adsorbents in removing pesticides which are, simultaneously, capable of releasing pesticides into the soil when needed. This reduces costs related to their application and waste treatments and, thus, overall environmental costs. In this paper, we describe the synthesis and preparation of activated carbon-containing poly(β-cyclodextrin) composites. The composites were characterized by different techniques and their ability to absorb pesticides was assessed by using two active substances: cymoxanil and imidacloprid. Composites with 5 and 10 wt% of activated carbon showed very good stability, high removal efficiencies (>75%) and pesticide sorption capacity up to ca. 50 mg g-1. The effect of additives (NaCl and urea) was also evaluated. The composites were able to release around 30% of the initial sorbed amount of pesticide without losing the capacity to keep the maximum removal efficiency in sorption/desorption cycles.

Molecularly imprinted films and quaternary ammonium-functionalized microparticles working in tandem against pathogenic bacteria in wastewaters

Despite major efforts to combat pollution, the presence of pathogenic bacteria is still detected in surface water, soil and even crops due to poor purification of domestic and industrial wastewaters. Therefore, we have designed molecularly imprinted polymer films and quaternary ammonium-functionalized- kaolin microparticles to target specifically Gram-negative bacteria (GNB) and Gram-positive bacteria (GPB) in wastewaters and ensure a higher purification rate by working in tandem. According to the bacteriological indicators, a reduction by 90 % was registered for GNB (total coliforms and Escherichia coli O157) and by 77 % for GPB (Clostridium perfringens) in wastewaters. The reduction rates were confirmed when using pathogen genetic markers to quantify particular types of GNB and GPB, like Salmonella typhimurium (reduction up to 100 %),Campylobacter jejuni (reduction up to 70 %), Enterococcus faecalis (reduction up to 81 %), Clostridium perfringens (reduction up to 97 %) and Shiga toxin-producing Escherichia coli (reduction up to 64 %). In order to understand the bactericidal activity of prepared films and microparticles, we have performed several key analyses such as Cryo-TEM, to highlight the auto-assembly mechanism of components during the films formation, and ²⁹ Si/¹³ C CP/MAS NMR, to reveal the way quaternary ammonium groups are grafted on the surface of kaolin microparticles.

Composite Nanogels Based on Zeolite-Poly(ethylene glycol) Diacrylate for Controlled Drug Delivery

This study presents the design of novel composites nanogels, based on poly(ethylene glycol) diacrylate and natural zeolite particles, that are able to act as materials with controlled drug delivery properties. Natural zeolite‒nanogels composite, with varying zeolite contents, were obtained by an inverse mini-emulsion technique and loaded with 5-fluorouracil, a widely used chemotherapeutic drug. Herein, the possibility of adjusting final properties by means of modifying the preparation conditions was investigated. The prepared composite nanogels are characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). In light of this tunable drug-loading capability, swelling behaviour, and cytotoxicity, these composite nanogels could be highly attractive as drug reservoirs.

Attempts to Upcycle PET Wastes into Bio-based Long-lasting Insulating Materials

Following the green chemistry principles, three series of polyols with tailored chemical structures were obtained from PET wastes degradation via glycolysis and/or aminolysis and subsequent esterification-transesterification and/or amidation reactions, using an organic catalyst. As cleaving agents there were used various mixtures of renewable or potentially renewable reagents, selected from those that can be obtained from biomass by already applied or investigated and eventually patented biochemical and/or chemical processes. The polyols were characterized by physical-chemical methods, 1H-NMR, 13C-NMR and FT-IR Spectroscopy, and tested in the synthesis of rigid polyurethane foams, showing appropriate properties for spray foams formation and leading to materials with properties similar to conventional spray foams.

Functionalized 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD) as Novel Organocatalyst for Efficient Depolymerization of Polyethylene Terephthalate (PET) Wastes

Poly(ethyleneterephthalate) waste was efficiently depolymerized through glycolysis and aminolysis reactions in the presence of functionalized 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD) catalyst. The new catalyst of monoamide-ester type, was synthesized through reaction of dimethylterephthalate (DMT) with TBD in refluxing benzene. It was developed as a consequence of the mechanistic investigations of the transesterification reaction of isosorbide with DMT. To test the stability of functionalized TBD compound towards possible amide bond breakage, reactions with primary and secondary glycols as well as primary amines were performed when only the carboxymethyl group reacted. Moreover, it was found that the depolymerization of poly(ethyleneterephthalate) wastes proceeds faster in the presence of this novel organocatalyst by comparison with the hygroscopic TBD precursor.

Development of Single-step Protocols for the Separation of Naphtodianthrones from St. John�s Wort Extracts

St. John s Wort (SJW) or Hypericum perforatum L. is a therapeutic plant highly used in pharmacology. Recent in vivo anti-cancer action of naphtodianthrones (NTs) has extended the research related to enrichment methodologies of SJW phyto-extracts. Therefore, the presented study pursuits the optimization of single-step extraction methodologies to obtain NTs-rich extracts from SJW.

Evaluating the Content of Active Principles from Wild Hypericum perforatum L. in Various Harvesting Seasons

Hypericum perforatum L., traditionally called St. John�s Wort has been used for decades as a phyto-therapeutic herb due to antidepressant, antimicrobial and antiseptic properties. As a result, the presented study evaluates the influence of the harvesting season for the Hypericum perforatum L. plant material, which is crucial for obtaining significant amounts of active principles.

Mechanistic Investigations of the Organocatalytic Depolymerization of PET Waste with Isosorbide

Glycolysis of PET waste with isosorbide, a biomass derived diol, was catalyzed by commercially available 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD) at temperature up to 190�C when low molecular weight oligomer containing at least one equivalent of isosorbide was obtained. The structural assignment of the oligomer product was established by NMR spectroscopy showing predominantly end-chain bonded isosorbide with exo/endo ratio of 55/45. Mechanistic considerations of the transesterification reaction of isosorbide with dimethylterephthalate (DMT) as model reaction revealed that the hydrogen bonding interaction of TBD with this diol is the favored mechanism pathway. This was established by corroborating solution NMR spectroscopy studies with DFT calculations at B3LYP level where it was observed that isosorbide is hydrogen bonded to TBD through both endo and exo hydroxyl groups. On the other hand, the TBD catalyst reacts with dimethylterephthalate at low temperature forming a stable, easy to handle covalently bonded adduct.

Bacterial cellulose-poly(acrylic acid-co-N,N′-methylene-bis-acrylamide) interpenetrated networks for the controlled release of fertilizers

In this study, composite hydrogels with interpenetrated polymer networks (IPNs), based on bacterial cellulose (BC) and poly(acrylic acid-co-N,N′-methylene-bis-acrylamide) (PAA), were synthesized by radical polymerization and characterized herein for the first time. Liquid fertilizer (LF) formulations, containing potassium, phosphorus, ammonium oxides and micronutrients, were encapsulated directly into the IPNs of the composite hydrogels during synthesis. Thermal analyses and scanning electron microscopy of control and composite xerogels highlighted the formation of IPNs between BC and PAA. Swelling determinations confirmed the influence of the crosslinker and of the liquid fertilizer concentration upon the density of the IPNs. Further rheology studies and release profiles indicated how the presence of BC and the increase of the crosslinking density of IPNs improved the mechanical strength and the release profile of LF for the innovative composite BC-PAA hydrogels. Results regarding the fertilizer release indicated that the presence of the BC led to a more controlled liberation of the fertilizer proving that this new formulation is potentially viable for application in agricultural practices.

In this study, composite hydrogels with interpenetrated polymer networks (IPNs), based on bacterial cellulose (BC) and poly(acrylic acid-co-N,N′-methylene-bis-acrylamide) (PAA) were synthesized by radical polymerization.

Commercial Gooseberry Buds Extract Containing Membrane for Removal of Methylene Blue Dye from Synthetic Wastewaters

In this work, a synthetic effluent containing Methylene blue dye has been treated by novel membrane enriched with commercial gooseberry buds extract using a mini-laboratory electrodialysis cell. The electrodialysis system was operated at various time and constant voltage applied at electrodes. Methylene blue removal percentage (CR %) and energy consumption (E.C.) were calculated. The obtained results showed that pH increase in solution and lead to an increase of deprotonated methylene groups, which may favor methylene dichloride complex formation. The values of CR % and E.C. increased with time. The high value of CR % was obtained at 60 min(CR] 89 %). The membranes were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Environmental Scanning Electron Microscopy (ESEM).

Efficient removal of Indigo Carmine dye by a separation process

This study is aimed at developing an innovative approach for Indigo Carmine dye removal from synthetic solutions by electrodialysis, carried out using ion exchange membranes. The batch electrodialysis system was operated at various current intensities: 0.05, 0.1 and 0.15 A. The pH and conductivity of solutions were measured before and after using electrodialysis process. The colour removal efficiency (CR %) was determined by spectrographic analysis and the energy consumption (EC) was calculated. The obtained results show that the pH of treated solution increases due to the increase in solution conductivity. Moreover, the values of CR % and EC increase when increasing current intensity. The optimal value was obtained at 0.15 A (CR > 97%). The membranes were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy.

New organophilic kaolin clays based on single-point grafted 3-aminopropyl dimethylethoxysilane

In this study, the organophilization procedure of kaolin rocks with a monofunctional ethoxysilane- 3 aminopropyl dimethyl ethoxysilane (APMS) is depicted for the first time. The two-step organophilization procedure, including dimethyl sulfoxide intercalation and APMS grafting onto the inner hydroxyl surface of kaolinite (the mineral) layers was tested for three sources of kaolin rocks (KR, KC and KD) with various morphologies and kaolinite compositions. The load of APMS in the kaolinite interlayer space was higher than that of 3-aminopropyl triethoxysilane (APTS) due to the single-point grafting nature of the organophilization reaction. A higher long-distance order of kaolinite layers with low staking was obtained for the APMS, due to a more controllable organiphilization reaction. Last but not least, the solid state (29)Si-NMR tests confirmed the single-point grafting mechanism of APMS, corroborating monodentate fixation on the kaolinite hydroxyl facets, with no contribution to the bidentate or tridentate fixation as observed for APTS.

Early Improvement in Glycemic Metabolism after Laparoscopic Sleeve Gastrectomy in Obese Patients - A Prospective Study

BACKGROUND

according to W.H.O. in 2014 more than 600 million adults were obese, (more than doubled since 1980), and face a major risk for the onset of metabolic syndrome, including T2DM. Due to the poor control of glycemic imbalance for the conservative treatment of T2DM, the metabolic surgery was able to gain an important role in modern management of T2DM, with significant reported improvements or remissions for these patients.

OBJECTIVE

to study the effects of laparoscopic sleeve gastrectomy (LSG) on glycemic metabolism in obese patients, with or without T2DM.

METHODS

60 consecutive patients were included in a prospective study and were submitted to laparoscopic sleeve gastrectomy in Ponderas Hospital between February - March 2013. BMI, waist circumference and glycemic parameters were studied at the moment of entering the study, 10 days after surgery and at 6 months follow up.

RESULTS

the glycemic control was significantly improved starting with postoperative day 10. Statistically significant improvements were noticed after six months postoperatively in BMI values (p 0,0001), waist circumference (p 0,0001), glycemic levels (p 0,0001), insulin (p 0,0001), C-peptide (p 0,0001) and HOMA.

CONCLUSIONS

a rapid induced improvement of glucose metabolism in both diabetic and non-diabetic patients occurs before a significant weight loss (POD 10). At 6 months, when associated with an important weight loss, both diabetic and non-diabetic patients present a furthermore improvement in glycemic metabolism, that enables us to consider that sleeve gastrectomy is an efficient method for a sustained improvement in the metabolic status of patients with obesity. These beneficial changes that can explain the remission of T2DM can also explain the prevention of T2DM after metabolic surgery.

Noninvasive clinical model for the diagnosis of nonalcoholic steatohepatitis in overweight and morbidly obese patients undergoing bariatric surgery

BACKGROUND

Liver biopsy, an invasive method, is the gold standard for differentiate nonalcoholic steatohepatitis (NASH) from other stages of fatty liver disease. A noninvasive test to diagnose NASH and disease severity before surgery and also for monitoring disease status after bariatric surgery (BS) will be an important medical challenge.

AIM

To create a noninvasive biomarkers model for the diagnosis of NASH in overweight, obese and morbidly obese patients (MOP).

PATIENTS AND METHODS

Sixty patients (mean BMI= 47.81kg/m2) were admitted after exclusion of other causes of liver disease. Liver biopsies were obtained at the time of the bariatric surgery or by percutaneous liver biopsy and graded using Kleiner score. Continuous variables were compared using Wilcoxon rank sum test and for prediction of NASH we used logistic regression.

RESULTS

Logistic regression analysis showed that BMI, ALT, AST, alkaline phosphatase (ALP), HOMA-R, hs-CRP, M30, M65, leptine and adiponectine levels remained independent predictors for NASH (p less than 0.02). Using AUC analysis, we established the following cutoff levels being indicative of NASH: BMI ė 47 kg/m2, ALT ė 32 IU/mL, AST ė 25 IU/mL, ALP ė 85 IU/mL, HOMA-IR ė 4, M65 ė 389 U/L. Adiponectine less than 13.5 mg/L. A NASH-score, calculated as the sum of these 7 parameters, at a cutoff level of 4 points, can accurately predict NASH (sensitivity of 90%, specificity of 93.94% and AUC of 0.9576).

CONCLUSIONS

We propose a noninvasive model for NASH diagnosis in MOP that should be validated prospectively. Using this noninvasive score, NASH would be predicted without the risks of liver biopsy.

West Nile fever in a patient in Romania, August 2008: case report

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