Assessment of liquid-liquid partition for the assignment of descriptors for the solvation parameter model.

The solvation parameter model uses five system independent descriptors to characterize compound properties defined as excess molar refraction, E, dipolarity/polarizability, S, hydrogen-bond acidity, A, hydrogen-bond basicity, B, and McGowan's characteristic volume, V, to model transfer properties between condensed phases. The V descriptor is assigned from structure. For compounds liquid at 20 °C the E descriptor can be assigned from the characteristic volume and its refractive index. The E descriptor for compounds solid at 20 °C and the S, A, and B descriptors are experimental properties traditionally assigned from chromatographic, liquid-liquid partition, and solubility measurements. In this report liquid-liquid partition constants in totally organic and aqueous biphasic systems are evaluated as a standalone technique for descriptor assignments. Using six totally organic biphasic systems the S, A, and B descriptors were assigned with an average absolute deviation (AAD) of about 0.04, 0.03, and 0.04, respectively, compared with the best estimate of the true descriptor values for 65 compounds. The E descriptor for compounds solid at 20 °C can only be estimated with an AAD of approximately 0.1. For six aqueous biphasic systems the B descriptor is assigned with a lower AAD of 0.028 and higher AAD of 0.08 and 0.05 for the S and A descriptors, respectively, than for the totally organic biphasic systems for compounds with a reliable value for the E descriptor. The preferred system for descriptor assignments utilizes both totally organic biphasic systems (heptane-1,1,1-trifluoroethanol, isopentyl ether-propylene carbonate, isopentyl ether-ethanolamine, heptane-ethylene glycol, heptane-formamide, and 1,2-dichloroethane-ethylene glycol) and aqueous biphasic systems (octanol-water, cyclohexane-water) with the possible substitution of some systems with alternative systems of similar selectivity. For 55 varied compounds this combination of eight organic and aqueous biphasic systems resulted in an AAD of approximately 0.03, 0.02, and 0.02 for the S, A, and B descriptors compared to the best estimate of the true descriptor value. For 30 compounds solid at 20 °C the AAD for the E descriptor of 0.11 is poorly assigned. The relative average absolute deviation in percent (RAAD) corresponds to 9.7 %, 3.1 %. 4.0 % and 8.3 % for E, S, A, and B, respectively, for the eight biphasic systems. Liquid-liquid partition is compared to reversed-phase liquid and gas chromatography as a standalone technique for descriptor assignments.

Comprehensive Assessment of Exposure Pathways for Perfluoroalkyl Ether Carboxylic Acids (PFECAs) in Residents Near a Fluorochemical Industrial Park: The Unanticipated Role of Cereal Consumption.

With the replacement of perfluorooctanoic acid (PFOA) with perfluorinated ether carboxylic acids (PFECAs), residents living near fluorochemical industrial parks (FIPs) are exposed to various novel PFECAs. Despite expectations of low accumulation, short-chain PFECAs, such as perfluoro-2-methoxyacetic acid (PFMOAA), previously displayed a considerably high body burden, although the main exposure routes and health risks remain uncertain. Here, we explored the distribution of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in diverse environmental media surrounding a FIP in Shandong Province, China. PFECAs were found at elevated concentrations in all tested matrices, including vegetables, cereals, air, and dust. Among residents, 99.3% of the ∑36PFAS exposure, with a 43.9% contribution from PFECAs, was due to gastrointestinal uptake. Dermal and respiratory exposures were negligible at 0.1 and 0.6%, respectively. The estimated daily intake (EDI) of PFMOAA reached 114.0 ng/kg body weight (bw)/day, ranking first among all detected PFECAs. Cereals emerged as the dominant contributor to PFMOAA body burden, representing over 80% of the overall EDI. The median EDI of hexafluoropropylene oxide dimer acid (HFPO-DA) was 17.9 ng/kg bw/day, markedly higher than the USEPA reference doses (3.0 ng/kg bw/day). The absence of established threshold values for other PFECAs constrains a comprehensive risk assessment.

Solvent-like bis (2-chloro-1-methylethyl) ether occurrence in drinking water: Multidimensional risk assessment integrated health and aesthetic aspects.

Bis (2-chloro-1-methylethyl) ether (DCIP), one U.S. Environmental Protection Agency priority pollutant, could pose health and/or odor risk in water environment. In this study, odor characteristics, occurrence and source of DCIP in drinking waters of China were investigated based on sensory analysis and a nation-wide investigation covering 140 drinking water treatment plants. Then multi-risk integrated health and aesthetic aspects through oral and inhalation (showering) exposure by drinking water were first estimated. Sensory evaluation showed DCIP exhibited "solvent-like" odor with thresholds of 34.8 ng/L in air and 142.0 ng/L in water. DCIP was detected at comparable concentrations in raw and finished waters (<1280 ng/L) and was by-product from industrial production of epichlorohydrin/propylene oxide. Lifetime Average Daily Dose through oral exposure was 0-36.65 ng/day/kg, corresponding to odor activity values of 0-8.4 and hazard quotients of far < 1, indicating drinking tap water might cause odor issues rather than significant health hazard. The proportion of sensitive population to DCIP's odor was 6.1%. In contrast, residents rarely detect DCIP's odor by inhalation. The presence in drinking water as industrial by-product, poor removal using conventional water treatment and potential to be T&O issues, indicates urgent demand for pollutant source control to protect DCIP from entering source waters.

Photodegradation of enestroburin in water by simulated sunlight irradiation: Kinetics, isomerization, transformation products identification and toxicity assessment.

Enestroburin is the first strobilurin fungicide developed by China and has been widely used to control fungal disease for 15 years. Investigation of its photolytic behaviour is essential for the comprehensive evaluation of its ecological risk. The effects of solution pH, humic acid (HA) and Fe(III) ions on photolysis were studied. The direct photolysis rates of enestroburin in the acidic solution (pH = 4) was faster than that in the basic (pH = 7) or neutral condition (pH = 9). HA and Fe3+ ions inhibited photolysis by the light screening effect. The photolysis of enestroburin was very fast due to the generation of photo-isomers. Seven isomeric products of enestroburin were observed using SFC-MS/MS, and the reaction mechanism for photo-induced isomers was proposed. The reaction occurred on three double bonds, including tautomerism of enol ether and oxonium and the triplet energy transfer of the CC and CN double bond. 12 transformation products (TPs) were identified by screening suspect compounds and non-target compounds, and one product (M-381) was synthesized for confirmation and quantification. A probable transformation mechanism was suggested based on the identified TPs and DFT calculations. The main transformation reactions included hydration, hydrolysis, oxidation, reduction and decarboxylation. Finally, the toxicities of the identified TPs and parent compound to aquatic organisms were predicted using ECOSAR software, and the toxicities of enestroburin and M-381 to daphnia magna were tested in the laboratory. The toxicity classification proposed by ECOSAR is reliable to a certain extent. Enestroburin and 2 TPs (M-313 and M-327) were classified as "very toxic", which may pose a potential threat to aquatic ecosystems.

Environmental impact assessment of nanofluids containing mixtures of surfactants and silica nanoparticles.

Due to widespread use of nanoparticles in surfactant-based formulations, their release into the environment and wastewater is unavoidable and toxic for biota and/or wastewater treatment processes. Because of concerns over the environmental impacts of nanofluids, studies of the fate and environmental impacts, hazards, and toxicities of nanoparticles are beginning. However, interactions between nanoparticles and surfactants and the biodegradability of these mixtures have been little studied until now. In this work, the environmental impacts of nanofluids containing mixtures of surfactants and silica nanoparticles were valuated. The systems studied were hydrophilic silica nanoparticles (sizes 7 and 12 nm), a nonionic surfactant (alkyl polyglucoside), an anionic surfactant (ether carboxylic acid), and mixtures of them. The ultimate aerobic biodegradation and the interfacial and adsorption properties of surfactants, nanoparticles, and mixtures during biodegradation were also evaluated. Ultimate biodegradation was studied below and above the CMCs of the individual surfactants. The interfacial and adsorption properties of surfactant solutions containing nanoparticles were influenced by the addition of silica particles. It was determined that silica nanoparticles reduced the capability of the nonionic surfactant alkyl polyglucoside to decrease the surface tension. Thus, silica NPs promoted a considerable increase in the surfactant CMC, whereas the effect was opposite in the case of the anionic surfactant ether carboxylic acid. Increasing concentrations of surfactant and nanoparticles in the test medium caused decreases in the maximum levels of mineralization reached for both types of surfactants. The presence of silica nanoparticles in the medium reduced the biodegradability of binary mixtures containing nonionic and anionic surfactants, and this effect was more pronounced for larger nanoparticles. These results could be useful in modelling the behaviour of nanofluids in aquatic environments and in selecting appropriate nanofluids containing nanoparticles and surfactants with low environmental impact.

Neurotoxicity assessment of QoI strobilurin fungicides azoxystrobin and trifloxystrobin in human SH-SY5Y neuroblastoma cells: Insights from lipidomics and mitochondrial bioenergetics.

Strobilurin fungicides are quinone outside inhibitors (QoI) used to treat fungal pathogens for agricultural and residential use. Here, we compared the potential for neurotoxicity of the widely used strobilurins, azoxystrobin (AZS) and trifloxystrobin (TFS), in differentiated human SH-SY5Y cells. Fungicides did not include cytotoxicity up to 200 µM but both induced loss of cell viability at 48 h, with TFS showing slightly higher toxicity that AZS. Caspase 3/7 activity was induced in SH-SY5Y cells by both fungicides at 48 h (50 µM for AZS and 25 µM for TFS). ATP levels were reduced following a 24-hour exposure to > 25 µM AZS and > 6.25 µM TFS and both fungicides rapidly impaired oxidative respiration (~12.5 µM for AZS and ~3.125 µM TFS) and decreased oligomycin-induced ATP production, maximal respiration, and mitochondrial spare capacity. AZS at 100 µM showed a continual impairment of mitochondrial membrane potential (MMP) between 4 and 48 h while TFS at > 50 µM decreased MMP at 24 h. Taken together, TFS exerted higher mitochondrial toxicity at lower concentrations compared to AZS in SH-SY5Y cells. To discern toxicity mechanisms of strobilurin fungicides, lipidomics was conducted in SH-SY5Y cells following exposure to 6.25 µM and 25 µM AZS, and a total of 1595 lipids were detected, representing 49 different lipid classes. Lipid classes with the largest proportion of lipids detected in SH-SY5Y cells included triglycerides (17%), phosphatidylethanolamines (8%), ether-linked triglycerides (8%), phosphatidylcholines (7%), ether-linked phosphatidylethanolamines (6%), and diacylglycerols (5%). Together, these 5 lipid classes accounted for over 50% of the total lipids measured in SH-SY5Y cells. Lipids that were increased by AZS included acyl carnitine, which plays a role in long chain fatty acid utilization for mitochondrial ß-oxidation, as well as non-modified, ether linked, and oxidized triacylglycerols, suggesting compensatory upregulation of triglyceride biosynthesis. The ceramide HexCer-NS, linked to neurodegenerative diseases, was decreased in abundance following AZS exposure. In summary, strobilurin fungicides rapidly inhibit mitochondrial oxidative respiration and alter the abundance of several lipids in neuronal cells, relevant for understanding environmental exposure risks related to their neurotoxicity.

Preclinical Toxicological Assessment of A Novel siRNA, SLN360, Targeting Elevated Lipoprotein (a) in Cardiovascular Disease.

SLN360 is a liver-targeted N-acetyl galactosamine (GalNAc)-conjugated small interfering RNA (siRNA) with a promising profile for addressing lipoprotein (a)-related cardiovascular risk. Here, we describe the findings from key preclinical safety studies. In vitro, SLN360 specifically reduced LPA expression in primary human hepatocytes with no relevant off-target effects. In rats, 10 mg/kg subcutaneous SLN360 was distributed specifically to the liver and kidney (peak 126 or 246 mg/g tissue at 6 h, respectively), with <1% of peak liver levels observed in all other tested organs. In vitro, no genotoxicity and no effect on human Ether-a-go-go Related Gene currents or proinflammatory cytokine production was observed, whereas in vivo, no SLN360-specific antibodies were detected in rabbit serum. In rat and nonhuman primate 29-day toxicology studies, SLN360 was well tolerated at all doses. In both species, known GalNAc-conjugated siRNA-induced microscopic changes were observed in the kidney and liver, with small increases in alanine aminotransferase and alkaline phosphatase observed in the high dose rats. Findings were in line with previously described siRNA-GalNAc platform-related effects and all observations were reversible and considered nonadverse. In cynomolgus monkeys, liver LPA messenger RNA and serum lipoprotein (a) were significantly reduced at day 30 and after an 8-week recovery period. No dose-related changes in safety assessment endpoints were noted. No SLN360-induced cytokine production, complement activation, or micronucleus formation was observed in vivo. The toxicological profile of SLN360 presented here is restricted to known GalNAc siRNA effects and no other toxicity associated with SLN360 has been noted. The preclinical profile of SLN360 confirmed suitability for entry into clinical studies.

Emerging and Legacy Per- and Polyfluoroalkyl Substances in an Elderly Population in Jinan, China: The Exposure Level, Short-Term Variation, and Intake Assessment.

Human exposure to per- and polyfluoroalkyl substances (PFASs) has gained worldwide attention due to their widespread presence in the environment and adverse health effects, but the exposure assessment in the elderly is still lacking. This study aimed to assess exposures to 3 emerging PFASs (chlorinated polyfluoroalkyl ether sulfonic acids, Cl-PFESAs) and 15 legacy PFASs. The temporal variability of internal exposures and intake amounts of these PFASs were evaluated among a population of 76 healthy elderly adults (age: 60-69) in Jinan, China over 5 consecutive months. Fifteen PFASs were detected in whole blood with the mean total concentration (ΣPFAS) at 20.1 ng/mL (range: 5.0-135.9 ng/mL) dominated by perfluorooctanoic acid (PFOA) (9.0 ng/mL), perfluorooctanesulfonic acid (PFOS) (5.3 ng/mL), and 6:2 Cl-PFESA (1.6 ng/mL). Across the 5 month assessment period, significant variation was only observed for short-chain (C4-C7) perfluoroalkyl carboxylic acids, and their variations ranged from 53 to 334%. The median intake of PFOA and PFOS was estimated to be 1.46 and 0.92 ng/kg bw/day, respectively. Regression analysis showed that dietary ingestion, especially fish, was likely an important exposure pathway for PFASs among the elderly adults. Various pathways (e.g., dietary, water, air, and dust) should thus be considered to fully understand human exposure to PFASs.

Safety Assessment of Ethers and Esters of Ascorbic Acid as Used in Cosmetics.

The Expert Panel for Cosmetic Ingredient Safety (Panel) reviewed the safety of 7 ethers and esters of ascorbic acid, which collectively function as antioxidants, skin-conditioning agents, skin protectants, fragrance ingredients, and skin bleaching agents in cosmetic products. The Panel reviewed relevant data relating to the safety of these ingredients, and concluded that the ethers and esters of ascorbic acid are safe in the present practices of use and concentration, as described in this safety assessment.

Amended Safety Assessment of Butyl Polyoxyalkylene Ethers as Used in Cosmetics.

The Expert Panel for Cosmetic Ingredient Safety (Panel) assessed the safety of 46 butyl polyoxyalkylene ethers that share a common structural motif, namely a butyl chain (4 carbon alkyl chain) bound to a polyoxyalkylene (PPG, PEG, or both); 23 of these ethers were previously reviewed by the Panel, and 23 are reviewed herein for the first time. Most of the butyl polyoxyalkylene ethers have several functions in cosmetics, but the most common reported functions include hair conditioning agent and skin conditioning agent, and many reportedly function as solvents. Upon review of new data, including frequency and concentration of use, and data from previous Panel reports and on read-across analogs, the Panel concluded that these ingredients are safe in the present practices of use and concentration in cosmetics when formulated to be non-irritating.

Single-Molecule Study of Thermomyces lanuginosus Lipase in a Detergency Application System Reveals Diffusion Pattern Remodeling by Surfactants and Calcium.

Lipases comprise one of the major enzyme classes in biotechnology with applications within, e.g., baking, brewing, biocatalysis, and the detergent industry. Understanding the mechanisms of lipase function and regulation is therefore important to facilitate the optimization of their function by protein engineering. Advances in single-molecule studies in model systems have provided deep mechanistic insights on lipase function, such as the existence of functional states, their dependence on regulatory cues, and their correlation to activity. However, it is unclear how these observations translate to enzyme behavior in applied settings. Here, single-molecule tracking of individual Thermomyces lanuginosus lipase (TLL) enzymes in a detergency application system allowed real-time direct observation of spatiotemporal localization, and thus diffusional behavior, of TLL enzymes on a lard substrate. Parallelized imaging of thousands of individual enzymes allowed us to observe directly the existence and quantify the abundance and interconversion kinetics between three diffusional states that we recently provided evidence to correlate with function. We observe redistribution of the enzyme's diffusional pattern at the lipid-water interface as well as variations in binding efficiency in response to surfactants and calcium, demonstrating that detergency effectors can drive the sampling of lipase functional states. Our single-molecule results combined with ensemble activity assays and enzyme surface binding efficiency readouts allowed us to deconvolute how application conditions can significantly alter protein functional dynamics and/or surface binding, both of which underpin enzyme performance. We anticipate that our results will inspire further efforts to decipher and integrate the dynamic nature of lipases, and other enzymes, in the design of new biotechnological solutions.

One-step preparation of photoclick method for embolic microsphere synthesis and assessment for transcatheter arterial embolization.

Vascular embolization is a well-known therapeutic treatment against hepatocellular carcinoma. However, existing embolic agents require complex synthesis, toxic organic solvents and sometimes produce only low yields. In this study, a novel photopolymerization technique, which addresses these issues, was used to prepare embolic microspheres successfully from the sucrose multi-allyl ether monomer in one step. Compared to the preparation of such microspheres always involved in multiple steps or complicated conditions, we obtained the microspheres used photoclick method in a soft template with simple, economic and feasible procedure. This work focuses on the synthesis of new materials by conducting a photopolymerzation in the presence of the sucrose monomer and the photoinitiator. Then, the embolic microspheres obtained were characterized by morphology assay, degradation, and swelling test. Cell experiments showed that the microspheres had good biocompatibility. Rabbit embolizations showed that the microspheres had long-term embolic effects. It is manifested that one-step preparation of photoclick method hold great potential and competitiveness of being used in preparation embolic microspheres in clinic.

The impact of sevoflurane anesthesia on postoperative renal function: a systematic review and meta-analysis of randomized-controlled trials.

PURPOSE: Renal damage secondary to fluoride ions and compound A (CpdA) after sevoflurane anesthesia remains unclear. For safety reasons, some countries still recommend minimum fresh-gas flows (FGFs) with sevoflurane. We review the evidence regarding the intraoperative use of sevoflurane for anesthesia maintenance and postoperative renal function compared with other anesthetic agents used for anesthetic maintenance. Secondarily, we examine the effects of peak plasma fluoride and CpdA levels and the effect of FGF and duration of anesthesia on these parameters. SOURCE: The databases of MEDLINE (OVID and Pubmed), EMBASE, the Cochrane Library, Health Technology Assessment Database, CINAHL, and Web of Science were searched from inception until 23 April 2020 to identify randomized-controlled trials (RCTs) in humans utilizing sevoflurane or an alternative anesthetic for anesthesia maintenance with subsequent measurements of renal function. Two different paired reviewers independently selected the studies and extracted data. The quality of the evidence was appraised using GRADE recommendations. PRINCIPAL FINDINGS: Of 3,766 publications screened, 41 RCTs in human patients were identified. There was no difference between creatinine at 24 hr (21 studies; n = 1,529), or creatinine clearance (CCR) at 24 hr (12 studies; n = 728) in the sevoflurane vs alternative anesthetic groups. Peak fluoride and fluoride measured at 24 hr were higher with sevoflurane compared with other inhaled anesthetics. Subgroup analyses for sevoflurane usage in various contexts showed no significant difference between sevoflurane and alternative anesthetics for creatinine or CCR at 24 hr at varying FGF, duration of exposure, baseline renal function, or absorbent use. CONCLUSIONS: We did not find any association between the use of sevoflurane and postoperative renal impairment compared with other agents used for anesthesia maintenance. The scientific basis for recommending higher FGF with the use of sevoflurane needs to be revisited.

RéSUMé: OBJECTIF: Les lésions rénales secondaires aux ions fluorure et au composé A (CpdA) après une anesthésie au sévoflurane demeurent incertaines. Pour des raisons de sécurité, certains pays recommandent encore des débits de gaz frais (DGF) minimaux lors de l'utilisation du sévoflurane. Nous avons passé en revue les données probantes concernant l'utilisation peropératoire de sévoflurane pour le maintien de l'anesthésie sur la fonction rénale postopératoire comparativement à d'autres agents anesthésiques utilisés pour le maintien de l'anesthésie. En analyse secondaire, nous avons examiné les effets des taux plasmatiques maximaux de fluorure et de CpdA et l'effet du DGF et de la durée de l'anesthésie sur ces paramètres. SOURCE: Des recherches ont été menées dans les bases de données de MEDLINE (OVID et Pubmed), EMBASE, the Cochrane Library, Health Technology Assessment Database, CINAHL et Web of Science, de leur création jusqu'au 23 avril 2020. Nous y avons identifié les études randomisées contrôlées (ERC) réalisées sur des sujets humains utilisant du sévoflurane ou un agent anesthésique alternatif pour le maintien de l'anesthésie et présentant des mesures subséquentes de la fonction rénale. Deux différents réviseurs appariés ont sélectionné de manière indépendante les études et extrait les données. La qualité des données probantes a été évaluée à l'aide des recommandations GRADE. CONSTATATIONS PRINCIPALES: Parmi les 3766 publications passées en revue, 41 ERC réalisées chez des patients humains ont été identifiées. Aucune différence n'a été observée en ce qui touchait à la valeur de créatinine à 24 h (21 études; n = 1529) ou de la clairance de la créatinine (CCR) à 24 h (12 études; n = 728) dans les groupes sévoflurane vs autres anesthésiques. Les taux maximaux de fluorure et le fluorure mesuré à 24 h étaient plus élevés lors de l'utilisation de sévoflurane que d'autres agents anesthésiques halogénés. Les analyses de sous-groupe portant sur l'utilisation du sévoflurane dans divers contextes n'ont démontré aucune différence significative entre le sévoflurane et les autres anesthésiques en matière de valeur de créatinine ou de CCR à 24 h selon différents DGF, durées d'exposition, fonctions rénales de base ou absorbants. CONCLUSION: Nous n'avons pas trouvé d'association entre l'utilisation du sévoflurane et des détériorations de la fonction rénale postopératoires par rapport aux autres agents utilisés pour le maintien de l'anesthésie. Les raisons scientifiques sur lesquelles repose la recommandation d'un DGF plus élevé lors de l'utilisation de sévoflurane doivent être réexaminées.

Synthesis and assessment of CTAB and NPE modified organo-montmorillonite for the fabrication of organo-montmorillonite/alginate based hydrophobic pharmaceutical controlled-release formulation.

The research goal of the present study was to develop a carrier for loading and controlled -release of the hydrophobic drug with the combined use of organo-montmorillonite (OMMT) and alginate. The OMMT was synthesized through the intercalation modification of sodium montmorillonite (Na-MMT) with cationic cetyltrimethylammonium bromide (CTAB), nonionic nonylphenol polyoxyethylene ether (NPE) and the mixture of them via simple and convenient wet ball-milling method. Furthermore, the organo-montmorillonite/alginate (OMMT/Alg) composite hydrogel beads with slow and controlled release properties were constructed by using alginate as a coating material under the exogenous cross-linking of calcium ions. The physical and chemical properties of OMMT were comparatively evaluated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analyzer (TGA), BET-specific surface area measurements, and drug adsorption experiments. Experimental results showed that the presence of CTAB was able to facilitate the intercalation of CTAB/NPE into Na-MMT through the cation exchange reaction. And the cationic CTAB and nonionic NPE were adsorbed or intercalated into the MMT lamellar structure through the wet ball-milling process, which could change the hydrophilic nature of Na-MMT and improve its affinity to the hydrophobic drug molecules. In addition, the OMMT/Alg composite hydrogel beads displayed superior sustained-release properties than Na-MMT/Alg, mainly ascribed to the good affinity of OMMT to hydrophobic drug that retarded the drug diffusion. In particular, CTA/NPE-MMT/Alg with the highest loading capacity (LC) and encapsulation efficiency (EE) revealed the optimal controlled performance for the release of hydrophobic ibuprofen. The release followed the Korsmeyer-Peppas model suggested non-Fickian diffusion release mechanism. Based on the high drug loading capacity and excellent controlled drug release properties, the CTA/NPE-MMT/Alg incorporating hydrophobic drugs into hydrophilic matrices could be a highly promising material for use in hydrophobic drug delivery.

Assessment of 3-dimensional bone augmentation of severely atrophied maxillary alveolar ridges using patient-specific poly ether-ether ketone (PEEK) sheets.

BACKGROUND: This study aimed to analyze the effectiveness of virtually designed polyether-ether ketone (PEEK) sheets to delineate and maintains the three-dimensional patient's maxillary alveolar ridge. MATERIALS AND METHODS: Fourteen patients (34 implants) with severely atrophied anterior maxillary alveolar ridges underwent rehabilitation using custom-made CAD/CAM PEEK sheets acting as a containment system for interpositional mix of particulate autogenous and xenogeneic bone graft, fixed by mono-cortical screws. Radiographic Assessment included measurements of linear changes in the vertical and horizontal dimensions on cross-sectional cuts of computed tomography (CBCT) using special software. RESULTS: Wound healing was uneventful for all the patients except one patient that showed wound break down 2 weeks postoperatively, which did not affect the outcome of the procedure. CBCT scans were interpreted to compare the quantity of both vertical and horizontal bone preoperatively and 6 months postoperatively. Statistical analyses demonstrated a significant difference between the results of both time intervals, with a mean vertical and horizontal bone gain was 3.47 mm(±1.46) and 3.42 (±1.1) with a P-value of (.0001). The customized sheets were removed 6 months postoperative with the successful placement of dental implants. CONCLUSION: The virtual planning of three-dimensional maxillary alveolar ridge augmentation utilizing patient-specific PEEK sheets deemed successful to restore the deficient ridge and to accommodate suitable size dental implants.

Developed a novel sensor based on fluorescent graft conjugated polymer for the determination of aristolochic acid in traditional Chinese medicine.

A novel fluorescent graft conjugated polymer (poly (2, 5-bis (Polyethylene glycol oxybutyrate)-1, 4-phenylethynylene-alt-1, 4-phenyleneethynylene, PPE-OB-PEG) has been designed and synthesized for the determination of aristolochic acid (AA). The detection conditions and detection characters of PPE-OB-PEG were systematically explored in this work. The fluorescence intensity of PPE-OB-PEG changes with the different concentration of AA. PPE-OB-PEG has a good linear range towards AA from 1.00 × 10-7 to 8.00 × 10-5 mol L-1 and the limit of detection (LOD) is 3.00 × 10-8 mol L-1 (S/N = 3). PPE-OB-PEG have been applied to detect AA in traditional Chinese medicine samples and the results are satisfactory. The experimental results show that PPE-OB-PEG can be used as a fluorescence probe for rapid and sensitive detection of AA.

Assessment of three dimensional bone augmentation of severely atrophied maxillary alveolar ridges using prebent titanium mesh vs customized poly-ether-ether-ketone (PEEK) mesh: A randomized clinical trial.

BACKGROUND: Alveolar bone grafting techniques and dental rehabilitation of patients with maxillary alveolar defects is a very challenging and costly procedure. Various methods have been described to reconstruct these defects in order to facilitate the placement of dental implants. The aim of this study was to assess three dimensional (3D) maxillary ridge augmentation using two innovative, accurate, and time saving protocols. MATERIALS AND METHODS: Sixteen patients (32 implants) with vertically and horizontally deficient maxillary alveolar ridges, were equally allocated into 2 groups; a mix of particulate autogenous and xenogenic bone grafts loaded in a prebent titanium mesh (Control group) vs patient specific poly-ether-ether ketone meshes (Study group). Radiographic assessment was performed preoperatively, 1 week and 6 months postoperatively. Assessment included measurements of linear changes in the vertical and horizontal dimensions on cross sectional cuts of cone beam computed tomography using special software. Finally; the percentage of 3D bone gain in each group was compared to that of the other. RESULTS: Wound healing was uneventful for all cases except one patient in each group were the meshes were exposed 2 weeks' postsurgery. There was no statistical significance between both groups (P value = 0.2). CONCLUSION: Within the limitations of the sample size of this study, both techniques could be used as a successful method of ridge augmentation with no statistical significance between them.