Abstract  1,4-Dioxane, used widely as a solvent in the manufacture of chemicals and as a laboratory reagent, induced liver adenomas and carcinomas in mice and rats, and nasal tumors in rats in several long-term studies. 1,4-Dioxane has been reported to be non-genotoxic in vitro, and there is no clear conclusion concerning its in vivo genotoxicity in rodents. In the present study, we investigated the ability of 1,4-dioxane to induce micronuclei in the liver and bone marrow of rats. For the liver micronucleus test, we performed the juvenile animal method and two methods using partial hepatectomy (PH), dosing before PH or dosing after PH. We also evaluated the in vivo mutagenicity of 1,4-dioxane by Pig-a gene mutation assay using rat peripheral blood. As a result, all methods of liver micronucleus test showed an increase in the frequency of micronucleated hepatocytes by 1,4-dioxane. The dosing before PH, a suitable method for detecting structural chromosome aberration inducers, showed the clearest response for micronucleated hepatocytes induction among the three methods. This finding is consistent with a previous report that 1,4-dioxane induces mainly chromosome breakage in the liver. Negative results were obtained in the bone marrow micronucleus test and Pig-a gene mutation assay in our study. These results suggested that 1,4-dioxane is clastogenic in the liver but not genotoxic in the bone marrow of rats.

Abstract  A series of magnesium complexes have been prepared and characterized, in which [(EDBP-Me)Mg(mu-OBn)](2) (4) has shown high activity toward the ring-opening polymerization (ROP) of epsilon-caprolactone and L-lactide. 2,2'-Ethylidene-bis(4,6-di-tert-butylphenol)-monomethyl ether ([EDBP-(Me)H]) is prepared by the reaction of 2,2'-ethylidene-bis(4,6-di-tert-butylphenol) (EDBP-H(2)) with dimethyl sulfate. The reaction of [EDBP-(Me)H] with (n)Bu(2)Mg yields [(EDBP-Me)Mg(n)Bu](2), which further reacts with benzyl alcohol and N,N-dimethylethylenediamine giving complexes [(EDBP-Me)Mg(mu-OBn)](2) (4) and {[EDBP(Me)]Mg(mu-Me(2)NCH(2)CH(2)NH)}(2) (5), respectively. Experimental results indicate that the activity of complex 4 toward cyclic esters is higher than that of [(mu-EDBP)Mg](2)/(BnOH).

Abstract  The ion-induced micellar transition is online-investigated by the time dependence of the viscosity of the solution under shear flow for the first time. During the morphological transition, the change in the micellar structure can be tracked by the change in viscosity. Adding HCl or CaCl2 into pre-prepared spherical micelle solution from the self-assembly of polystyrene-block-poly(acrylic acid) (PS144-b-PAA22) in the N,N-dimethylformamide (DMF)/water mixture, the micellar structures change into short cylinders, long, entangled cylinders, and then lamellae or vesicles, corresponding to the viscosity increasing first and then declining. When HCl or CaCl2 is added to the pre-prepared spherical micelle solution formed by PS144-b-PAA50 in the dioxane/water mixture, the micellar structures are quickly transformed into cylinders or lamellae before carrying out the rheological measurement and then are turned to vesicles or spheres under the shearing, corresponding to a gradual decline in viscosity. This study shows that the rheology can be a very simple and effective online method on the investigation of the micellization, which plays an important role in understanding the micellization mechanism and micellar transition pathway of block copolymers in dilute solution.

Abstract  A series of novel 4-amino-6-(1,3,4-oxadiazolo/1,3,4-thiadiazolo)-pyrimidine derivatives of biological interest were prepared by sequential amination, hydrazide formation, and hydrazine carbothioamidination followed by cyclization. All the synthesized compounds (6a-6h and 7a-7f) were screened for antibacterial and antifungal activity. From this group, compound 7f (MIC (μg/mL μg/mL )/Inhibition (mm): 6.25/23-30) showed good antibacterial and antifungal activity. Reagents and conditions: (a) Ethyl acetoacetate, 60% NaH, 1,4-dioxane, 60°C, 6 h; (b) DIPEA, 1,4-dioxane, 100°C, 14 h; (c) NH2NH2 ⋅ H2O, EtOH, reflux, 14 h; (d) Tolyl isothiocyanatobenzene, DMF, RT, 2 h; (e) (if X = O) EDC⋅ HCl, TEA, DMF, RT, 14 h; (f) (if X = S) Conc. H2O4, RT, 14h.

Abstract  Here a new, mild and versatile method for efficient synthesis of a diverse range of 2-acetate substituted indoles via Rh(III)-catalyzed and alcohol-mediated C2-selective carbenoid insertion functionalization of indoles by α-diazotized Meldrum's acid has been developed. Furthermore, for the first time, a Rh(III)/Cu(II)-catalyzed direct C7-alkenylation of such functionalized products has also been demonstrated.

Abstract  The optimal conditions for the isolation of beta-cypermethrin from biological materials by means of dioxane extraction have been developed. The possibility to purify beta-cypermethrin from endogenous impurities is demonstrated by combination of liquid-liquid extraction and chromatography through a silica gel column (L 40/100 mcm). It is shown that identification and quantitative determination of beta-cypermethrin extracted from the cadaveric liver tissues are possible using such techniques as thin-layer chromatography, electron spectrometry, and chromato-mass spectrometry. A method for forensic chemical expertise of the presence of beta-cypermethrin in biological materials is described.

Abstract  BACKGROUND: Immobilization of enzymes onto different carriers increases enzyme's stability and reusability within biotechnological and pharmaceutical applications. However, some immobilization techniques are associated with loss of enzymatic specificity and/or activity. Possible reasons for this loss are mass transport limitations or structural changes. For this reason an immobilization method must be selected depending on immobilisate's demands. In this work different immobilization media were compared towards the synthetic and hydrolytic activities of immobilized trypsin as model enzyme on magnetic micro-particles.

RESULTS: Porcine trypsin immobilization was carried out in organic and aqueous media with magnetic microparticles. The immobilization conditions in organic solvent were optimized for a peptide synthesis reaction. The highest carrier activity was achieved at 1 % of water (v/v) in dioxane. The resulting immobilizate could be used over ten cycles with activity retention of 90 % in peptide synthesis reaction in 80 % (v/v) ethanol and in hydrolysis reaction with activity retention of 87 % in buffered aqueous solution. Further, the optimized method was applied in peptide synthesis and hydrolysis reactions in comparison to an aqueous immobilization method varying the protein input. The dioxane immobilization method showed a higher activity coupling yield by factor 2 in peptide synthesis with a maximum activity coupling yield of 19.2 % compared to aqueous immobilization. The hydrolysis activity coupling yield displayed a maximum value of 20.4 % in dioxane immobilization method while the aqueous method achieved a maximum value of 38.5 %. Comparing the specific activity yields of the tested immobilization methods revealed maximum values of 5.2 % and 100 % in peptide synthesis and 33.3 % and 87.5 % in hydrolysis reaction for the dioxane and aqueous method, respectively.

CONCLUSIONS: By immobilizing trypsin in dioxane, a beneficial effect on the synthetic trypsin activity resilience compared to aqueous immobilization medium was shown. The results indicate a substantial potential of the micro-aqueous organic protease immobilization method for preservation of enzymatic activity during enzyme coupling step. These results may be of substantial interest for enzymatic peptide synthesis reactions at mild conditions with high selectivity in industrial drug production.

Abstract  Two series of aluminum alkyl complexes supported by pyrrolylaldiminate ligands, LAlMe2 (1a-7a) and L2AlMe (1b-7b), were successfully synthesized and characterized by NMR spectroscopy and elemental analysis. Reactions of trimethylaluminum with the corresponding pyrrolylaldiminate ligands in the molar ratios of 1 : 1 and 1 : 2 yielded dimethylaluminum pyrrolylaldiminates (1a-7a) and monomethylaluminum pyrrolylaldiminates (1b-7b), respectively, in good yields. The structure of 3b, determined by single-crystal X-ray diffraction, displayed a distorted trigonal bipyramidal geometry with the τ value of 0.65. Upon addition of 1 equivalent of benzyl alcohol, all complexes promoted the living ring-opening polymerization of rac-lactide with a good control over molecular weights and polydispersities. Complexes 6a and 7a were found to efficiently mediate the immortal polymerization in the presence of excess equivalents of benzyl alcohol (up to 5 equivalents), as evidenced by the narrow PDI values and the good agreement between the experimental M(n) values and monomer/benzyl alcohol ratios. The steric and electronic effects of the imine nitrogen substituents had a strong influence on the polymerization activities both in catalytic activity and polymer microstructure. The catalytic activity decreased as follows: 4-Me-C6H4 (3) > C6H5 (1) ≈ 4-F-C6H4 (2) ≈ 2-Me-C6H4 (5) > 4-OMe-C6H4 (4) ≫ 2-(t)Bu-C6H4 (6) > adamantyl (7). In comparison, the catalytic activity of the monomethylaluminum complex is slightly higher than that of the dimethylaluminum counterpart. The polymerization of rac-lactide by 6b yielded heterotactically enriched polylactide (P(r) = 0.60) whereas the isotactic-enriched polymer (P(m) = 0.74) was obtained from 7b.

Abstract  BACKGROUND: Systemic inflammatory response syndrome (SIRS) may develop after aneurysmal subarachnoid hemorrhage (SAH). We investigated factors associated with SIRS after SAH, whether SIRS was associated with complications of SAH such as vasospasm, cerebral infarction, and clinical outcome, and whether SIRS could contribute to a difference in outcome between patients treated by endovascular coiling or neurosurgical clipping of the ruptured aneurysm.

METHODS: This was exploratory analysis of 413 patients in the CONSCIOUS-1 study. SIRS was diagnosed if the patient had at least 2 of 4 variables (hypothermia/fever, tachycardia, tachypnea, and leukocytosis/leukopenia) within 4 days of admission. Clinical outcome was measured on the Glasgow outcome scale 3 months after SAH. The relationship between clinical and radiologic variables and SIRS, angiographic vasospasm, delayed ischemic neurologic deficit (DIND), cerebral infarction, vasospasm-related infarction, and clinical outcome were modeled with uni- and multivariable analyses.

RESULTS: 63% of patients developed SIRS. Many factors were associated with SIRS in univariate analysis, but only poor WFNS grade and pneumonia were independently associated with SIRS in multivariable analysis. SIRS burden (number of SIRS variables per day over the first 4 days) was associated with poor outcome, but not with angiographic vasospasm, DIND, or cerebral infarction. The method of aneurysm treatment was not associated with SIRS.

CONCLUSION: SIRS was associated with poor outcome but not angiographic vasospasm, DIND, or cerebral infarction after SAH in the CONSCIOUS-1 data. There was no support for the notion that neurosurgical clipping is associated with a greater risk of SIRS than endovascular coiling.

Abstract  OBJECT: Atrophy in specific brain areas correlates with poor neuropsychological outcome after subarachnoid hemorrhage (SAH). Few studies have compared global atrophy in SAH with outcome. The authors examined the relationship between global brain atrophy, clinical factors, and outcome after SAH.

METHODS: This study was a post hoc exploratory analysis of the Clazosentan to Overcome Neurological Ischemia and Infarction Occurring After Subarachnoid Hemorrhage (CONSCIOUS-1) trial, a randomized, double-blind, placebo-controlled trial of 413 patients with aneurysmal SAH. Patients with infarctions or areas of encephalomalacia on CT, and those with large clip/coil artifacts, were excluded. The 97 remaining patients underwent CT at baseline and 6 weeks, which was analyzed using voxel-based volumetric measurements. The percentage difference in volume between time points was compared against clinical variables. The relationship with clinical outcome was modeled using univariate and multivariate analysis.

RESULTS: Older age, male sex, and systemic inflammatory response syndrome (SIRS) during intensive care stay were significantly associated with brain atrophy. Greater brain atrophy was significantly associated with poor outcome on the modified Rankin scale (mRS), severity of deficits on the National Institutes of Health Stroke Scale (NIHSS), worse executive functioning, and lower EuroQol Group-5D (EQ-5D) score. Adjusted for confounders, brain atrophy was not significantly associated with Mini-Mental State Examination and Functional Status Examination scores. Brain atrophy was not associated with angiographic vasospasm or delayed ischemic neurological deficit.

CONCLUSIONS: Worse mRS score, NIHSS score, executive functioning, and EQ-5D scores were associated with greater brain atrophy and older age, male sex, and SIRS burden. These data suggest outcome is associated with factors that cause global brain injury independent of focal brain injury.

Abstract  Increasing attention has recently been paid to the fabrication of drug delivery systems with excellent cell internalization and intracellular drug release properties. In this study, an amphiphilic block copolymer of chitosan was synthesized for the first time, which can self-assemble into micelles in a neutral aqueous solution but partially disassemble in an acidic endosomal/lysosomal environment. The antitumor drug, camptothecin (CPT), was encapsulated in the cores of the micelles for tumor cell therapy. In vitro drug release studies demonstrated that the micelles presented a much faster release of CPT at pH 5.0 than at pH 7.4. Blank micelles were found to be nontoxic in preliminary in vitro cytotoxicity assays. Cell experiments showed that the CPT-loaded micelles could be effectively internalized by Hela cells and accomplished a potent antitumor cell efficacy, indicating that the chitosan-based micelles might be an attractive new platform for efficient intracellular drug delivery.

Abstract  BACKGROUND: This prospective cohort study evaluated whether partially absorbable monofilament mesh could influence postoperative pain and time of the return to normal activity while not increasing recurrence in modified Lichtenstein inguinal hernioplasty.

METHODS: Two hundred and forty-two patients were operated on using poliglecaprone/polypropylene mesh. A modified Lichtenstein technique was used (more stitches and larger margin of mesh on the inguinal ligament, additional suture near the pubic bone). Follow-up data were collected at 3 years. The objective was to assess the incidence of late persistent postoperative pain and the recurrence rate.

RESULTS: The follow-up rate reached 88.37%. The recurrence rate was 2.2% (four patients). All recurrences appeared within the first 12 months. Slight discomfort, feelings of stiffness, and the occasional appearance of foreign bodies that did not influence daily activity were noted in 20 patients (10.8%). Chronic pain was found in 22 patients (11.1%), but only affected the daily activities of seven (3.24%). Only one patient suffering from pain described it as stronger than before the operation.

CONCLUSIONS: The use of partially absorbable light mesh reduces postoperative pain at long-term follow-up. The recurrence rate was not increased at 36 months follow-up.

Abstract  Porous tubular poly(trimethylene carbonate) (PTMC) scaffolds for vascular tissue engineering, with an inner diameter of 3 mm and a wall thickness of 1 mm, were prepared by means of dip-coating and subsequent leaching of NaCl particles. The scaffolds, with an average pore size of 110 μm and a porosity of 85%, showed a smooth muscle cell (SMC) seeding efficiency of only 10%. To increase the efficiency of cell seeding, these scaffolds were coated with a microporous PTMC outer layer with a thickness of 0.1-0.4 mm, an average pore size of 28 μm, and a porosity of 65%. Coating of the scaffolds with the microporous outer layer did not influence the inner pore structure or the mechanical properties of the scaffolds to a significant extent. The intrinsic permeability of the scaffolds decreased from 60 × 10(-10) m(2) to approximately 5 × 10(-10) m(2) after coating with the microporous outer layer. The latter value is still relatively high indicating that these scaffolds may facilitate sufficient diffusion of nutrients and waste products during cell culturing. The efficiency of SMC seeding determined after 24 h cell adhesion in the scaffolds increased from less than 10% to 43% after coating with the microporous outer layer. The cells were homogeneously distributed in the scaffolds and cell numbers increased 60% during culturing for 7 days under stationary conditions. It is concluded that coating of porous tubular PTMC scaffolds with a microporous PTMC outer layer facilitates effective cell seeding in these scaffolds.

Abstract  A series of oxadiazole derivatives containing 1,4-benzodioxan (4a-4s) have been first synthesized for their potential immunosuppressive activity. Among the compounds, compound 4i showed the most potent biological activity against RAW264.7 cells (inhibition=37.66±2.34% for NO overproduction and IC(50)=0.05μM for iNOS). Docking simulation was performed to position compound 4i into the iNOS structure active site to determine the probable binding model. RT-PCR experiment results demonstrated that some of these compounds possessed good immunosuppressive activity against iNOS, especially for compound 4i. Therefore, compound 4i with potent inhibitory activity may be a potential agent.

Abstract  INTRODUCTION: Extraction and characterisation of hemicelluloses are very important for converting them into functional materials and chemicals.

OBJECTIVE: To develop a method for isolation of hemicelluloses from all cell walls.

METHODOLOGY: Sequential steps using 90% dioxane, 80% acidic dioxane, 100% dimethyl sulphoxide and 8% NaOH were used for extraction of the hemicellulosic preparations (H(1), H(2), H(3) and H(4)) from maize stem. Advanced NMR techniques were used for the analysis of native hemicelluloses.

RESULTS: Hemicelluloses with high yieldd were isolated from all cell walls, and contained arabinoxylan as the major polysaccharide. H(3) was substituted by α-L-arabinofuranose, α-D-xylopyranose, and acetyl groups (degree of saturation = 0.12/0.09) at O-3/O-2 of xylan. H(4) had a long continuous side chain of arabinose residues, and associated closely with non-cellulosic glucose. The hemicelluloses formed more linkages with guaiacyl lignins, and some p-coumaric acids built a bridge between hemicelluloses and lignin in maize stem.

CONCLUSION: This modified method is successful for the isolation of hemicelluloses with high yields from all cell walls of maize stem.

Abstract  Ethylene glycol (EG) is a group of dihydroxy alcohol that has been utilised in a variety of industrial and residential settings. EG contaminated wastewater has a high chemical oxygen demand (COD), which causes environmental problems. The aim of this research was to investigate the efficiency of the burhead plant (Echinodorus cordifolius (L.)) in the removal of mono-, di- and triethylene glycol (MEG, DEG and TEG), the first three members of the dihydroxy alcohol group, from synthetic wastewaters, to examine the toxic effect of EG on the plant and to identify differences among MEG, DEG, and TEG removal. It was found that the COD of synthetic wastewaters decreased to levels below the standard effluent (COD=120 mg L⁻¹) on day 18, 21 and 33 for MEG, DEG and TEG, respectively. On day 18 of the experiment, the burhead plant removed approximately 2000, 1950 and 730 mg L⁻¹ of MEG, DEG and TEG, respectively. The removal rate of MEG was faster than that of DEG and TEG, suggesting that the molecular size of the EG had affected its rate of removal. The concentrations of MEG, DEG, and TEG in plant tissue were measured to show that burhead can take up EG, and the major site of EG accumulation is the leaf. The molar of MEG that was taken up into the plant leaf was higher than that of DEG and TEG. This suggested that EG of smaller molecular sizes can be taken up more rapidly by the plant than EG of larger molecular sizes. EG concentrations in the leaf increased to a peak concentration and then slowly decreased. GC-MS analysis of DEG-treated plant tissue found MEG, 1,4-dioxan-2-one, neophytadiene, and 2-propenamide, that may be DEG-degradation products and/or compounds that are induced when plants are exposed to DEG. The result indicates that burhead can potentially be used for EG removal.

Abstract  Green chemistry is the design of chemical processes that reduce or eliminate negative environmental impacts. The use and production of chemicals involve the reduction of waste products, non-toxic components, and improved efficiency. Green chemistry applies innovative scientific solutions in the use of new reagents, catalysts and non-classical modes of activation such as ultrasounds or microwaves. Kinetic behavior and non-thermal effect of poly(amic acid) synthesized from (6FDA) dianhydride and (BAPHF) diamine in a low microwave absorbing p-dioxane solvent at low temperature of 30, 50, 70 °C were studied, under conventional heating (CH), microwave (MW) and ultrasound irradiation (US). Results show that the polycondensation rate decreases (MW > US > CH) and that the increased rates observed with US and MW are due to decreased activation energies of the Arrhenius equation. Rate constant for a chemical process activated by conventional heating declines proportionally as the induction time increases, however, this behavior is not observed under microwave and ultrasound activation. We can say that in addition to the thermal microwave effect, a non-thermal microwave effect is present in the system.

Abstract  The activation energy for intramolecular electron transfer in radical anions of 2,7-dinitrodibenzodioxin and 2,8-dinitrodibenzodioxin, obtained by simulation of their temperature-dependent EPR spectra, are well predicted by the values calculated by the two-state Marcus-Hush model from the optical charge-transfer bands using quartic-adjusted energy surfaces. The electronic coupling is higher in the 2,8-dinitrodibenzodioxin (H(ab) = 485 cm(-1)) than in the 2,7-dinitrodibenzodioxin radical anion (H(ab) = 250 cm(-1)), but for each solvent the reorganization energy, taken as the maximum of the optical band, is only slightly higher in the latter. These values are consistent with the fact that the reaction is faster in the 2,8-dinitrodibenzodioxin radical anion isomer, as determined by EPR spectroscopy. The pre-exponential factors obtained combining the EPR-derived rate constants and the activation energies calculated from the optical bands fit well the theoretical (modified) nonadiabatic values in the less viscous solvents. However, for the more viscous solvents, the trend of the pre-exponential values with solvent can only be explained if dynamical solvent effects increasingly influence their value. The influence of solvent dynamics in the 2,8-dinitrodibenzodioxin radical anion starts in the less viscous solvents DMF and DMSO, but in the 2,7-dinitrodibenzodioxin isomer this is only fully evident for the more viscous PhCN and HMPA. The influence of solvent dynamics is higher in the radical with the lowest activation barrier.

Abstract  The employment of biodegradable polymer scaffolds is one of the main approaches for achieving a tissue engineered construct to reproduce bone tissues, which provide a three dimensional template to regenerate desirable tissues for different applications. The main goal of this study is to design a novel triblock scaffold reinforced with nano-hydroxyapatite (nHA) for hard tissue engineering using gas foaming/salt leaching method with minimum solvent usage. With this end in view, the biodegradable triblock copolymers of l-lactide and ε-caprolactone with different mol% were synthesized by ring-opening polymerization method in the presence of Sn(Oct)2 catalyst as initiator and ethylene glycol as co-initiator. The chemical compositions of biodegradable copolymers were characterized by means of FTIR and NMR. The thermal and crystallization behaviors of copolymers were characterized using TGA and DSC thermograms. Moreover, nano-hydroxyapatite was synthesized by the chemical precipitation process and was thoroughly characterized by FTIR, XRD and TEM. Additionally, the nanocomposites with different contents of nHA were prepared by mixing triblock copolymer with nHA. Mechanical properties of the prepared nanocomposites were evaluated by stress-strain measurements. It was found that the nanocomposite with 30% of nHA showed the optimum result. Therefore, nanocomposite scaffolds with 30% nHA were fabricated by gas foaming/salt leaching method and SEM images were used to observe the microstructure and morphology of nanocomposites and nanocomposite scaffolds before and after cell culture. The in-vitro and cell culture tests were also carried out to further evaluate the biological properties. The results revealed that the porous scaffolds were biocompatible to the osteoblast cells because the cells spread and grew well. The resultant nanocomposites could be considered as good candidates for use in bone tissue engineering.

Abstract  Phase separation of a polymer solution exhibits a peculiar behavior when induced in a nanoconfinement. The energetic constraints introduce additional interactions between the polymer segments that reduce the number of available configurations. In our work, this effect is exploited in a one-step strategy called nanoconfined-Thermally Induced Phase Separation (nc-TIPS) to promote the crystallization of polymer chains into nanocapsular structures of controlled size and shell thickness. This is accomplished by performing a quench step of a low-concentrated PLLA-dioxane-water solution included in emulsions of mean droplet size <500 nm acting as nanodomains. The control of nanoconfinement conditions enables not only the production of nanocapsules with a minimum mean particle diameter of 70 nm but also the tunability of shell thickness and its crystallinity degree. The specific properties of the developed nanocapsular architectures have important implications on release mechanism and loading capability of hydrophilic and lipophilic payload compounds.