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1.
Heliyon ; 10(10): e31547, 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38818155

RESUMO

This study investigates the degradation of TCB in methanol, ethanol, hexane, and benzene solutions using gamma radiolysis. Kinetic properties of TCB dechlorination and its pathway are examined, with TCB selected as a representative chlorinated organic compound. Chromatograms of irradiated samples and mass spectra of liquid-phase products are presented. The change in concentration of TCB, dichlorobenzenes (DCB), chlorobenzene (MCB), and benzene with absorbed doses are observed. The radiation-chemical yield (G values) of TCB in the solvents are calculated as 1.83, 2.56, 1.93, and 1.84 100eV-1 in methanol, ethanol, hexane, and benzene solutions, respectively. 100 % degradation of TCB by gamma irradiation is found to be efficient in polar solvents but leads to a wide variety of byproducts in low polar solvents, particularly the formation of polychlorinated biphenyls in TCB + benzene solutions, making benzene an incompatible medium. The main dechlorination pathway of TCB involves the formation of 1,4-DCB, MCB, and benzene. Environmental Implication. The gamma irradiation of chlorinated organic compounds, focusing on TCB as a model compound, was investigated due to its status as a hazardous material for the environment and living organisms. TCB is a byproduct of the dechlorination of certain chlorinated pesticides listed under the Stockholm Convention's Persistent Organic Pollutants (POPs) list, which prohibits their production and use. Gamma irradiation was found to be an effective method for the degradation of chlorinated compounds, achieving 100 % degradation during irradiation. The study underscores the potential of gamma irradiation as a viable approach for the treatment of chlorinated compounds, particularly in addressing environmental and health concerns associated with TCB and related compounds.

2.
Langmuir ; 29(24): 7439-48, 2013 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-23214412

RESUMO

Long-lasting anticorrosive coatings for steel have been developed on the basis of halloysite nanotubes loaded with three corrosion inhibitors: benzotriazole, mercaptobenzothiazole, and mercaptobenzimidazole. The inhibitors' loaded tubes were admixed at 5-10 wt % to oil-based alkyd paint providing sustained agent release and corrosion healing in the coating defects. The slow 20-30 h release of the inhibitors at defect points caused a remarkable improvement in the anticorrosion efficiency of the coatings. Further time expansion of anticorrosion agent release has been achieved by the formation of release stoppers at nanotube ends with urea-formaldehyde copolymer and copper-inhibitor complexation. The corrosion protection efficiency was tested on ASTM A366 steel plates in a 0.5 M NaCl solution with the microscanning of corrosion current development by microscopy inspection and studying paint adhesion. The best protection was found using halloysite/mercaptobenzimidazole and benzotriazole inhibitors. Stopper formation with urea-formaldehyde copolymer provided an additional increase in corrosion efficiency as a result of the longer release of inhibitors.

3.
J Nanosci Nanotechnol ; 11(11): 10007-26, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22413340

RESUMO

Halloysite is a naturally occurring clay mineral with submicron sized hollow cylindrical morphology. Halloysite morphology, structure and properties were characterized by using SEM, TEM, XRD, FT-IR spectroscopy, surface electrokinetic (zeta) potential and nitrogen adsorption isotherms. Comparison of the halloysite structure with imogolite was also provided. Halloysite toxicological studies revealed that it is environmentally friendly and biocompatible material. Due to its unique tubular shape and availability in thousands of tons halloysite has potential to be applied as nanocontainers for encapsulation of chemically and biologically active agents such as medicines, pharmaceuticals, antiseptics, corrosion inhibitors, antifouling agents, and doped with them plastics producing smart polymeric nanocomposites with improved mechanical strength. Finally possibility to synthesize metal nanorods within the halloysite lumen was demonstrated.


Assuntos
Silicatos de Alumínio/química , Nanocápsulas/química , Nanotubos/química , Substâncias Protetoras/química , Animais , Materiais Biocompatíveis/química , Argila , Preparações de Ação Retardada , Humanos , Camundongos , Nanocápsulas/ultraestrutura , Nanotubos/ultraestrutura , Substâncias Protetoras/administração & dosagem
4.
Biomacromolecules ; 11(3): 820-6, 2010 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-20170093

RESUMO

Halloysite is aluminosilicate clay with hollow tubular structure of 50 nm external diameter and 15 nm diameter lumen. Halloysite biocompatibility study is important for its potential applications in polymer composites, bone implants, controlled drug delivery, and for protective coating (e.g., anticorrosion or antimolding). Halloysite nanotubes were added to different cell cultures for toxicity tests. Its fluorescence functionalization by aminopropyltriethosilane (APTES) and with fluorescently labeled polyelectrolyte layers allowed following halloysite uptake by the cells with confocal laser scanning microscopy (CLSM). Quantitative Trypan blue and MTT measurements performed with two neoplastic cell lines model systems as a function of the nanotubes concentration and incubation time indicate that halloysite exhibits a high level of biocompatibility and very low cytotoxicity, rendering it a good candidate for household materials and medicine. A combination of transmission electron microscopy (TEM), scanning electron microscopy (SEM), and scanning force microscopy (SFM) imaging techniques have been employed to elucidate the structure of halloysite nanotubes.


Assuntos
Silicatos de Alumínio , Nanotubos , Linhagem Celular Tumoral , Argila , Humanos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão
5.
Urol Case Rep ; 10: 19-22, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27896133

RESUMO

Self-mutilation is the deliberate direct injuring of body tissue, often done without suicidal intention. Genital self-mutilation is a very rare event and self-harm of the penis, especially in the genital system is exceedingly rare. Generally, this kind of behavior is related to psychotic disorders but can sometimes be seen in non-psychotic people due to bizarre autoerotic acts, a desire for to change sex or religious beliefs that view sexual intercourse as a sin. Our case was the reported genital self-mutilation as a result of the bizarre sexual arousal of a young man who is employed as an architect.

6.
Urol J ; 11(2): 1423-8, 2014 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-24807754

RESUMO

PURPOSE: To compare the efficacy of laparoscopic and open ureterolithotomy in patients with ureteral stones. MATERIALS AND METHODS: Patients who had undergone open or laparoscopic ureterolithotomy between 2001 and 2013 in our clinic were enrolled in the study.Ureterolithotomy was performed due to the following reasons: failure to position the patient for ureteroscopy, unreachable stone with ureteroscopy also use of balloon dilatation, high stone volume, and the need for removal of kidney stones at the same session.. The patients' demographic data, the volume of the stones, the duration of the operation and the hospital stay, the amount of analgesics administered after the operation, and the need for another procedure were compared. RESULTS: Of study subjects 32 patients had undergone open and 20 patients had undergone laparoscopic ureterolithotomy. When the two groups were compared, there was no statistically significant difference with regard to the mean age (44.5-44 years), the body mass index (26-24.7 kg/m²), the stone volume (420-580 mm³), the duration of operation (122-123 min), the need for another procedure and complications. The mean amount of analgesics administered after the operation (3.6 and 1.81 doses, P = .02) and the mean hospital stay (6.1 and 2.9 days, P = .01) were significantly lower in the laparoscopic ureterolithotomy group. CONCLUSION: Laparoscopic ureterolithotomy is a good alternative with less need for analgesia and a shorter hospital stay when compared with open ureterolithotomy.


Assuntos
Laparoscopia , Cálculos Ureterais/cirurgia , Adulto , Feminino , Humanos , Masculino , Estudos Retrospectivos , Cálculos Ureterais/complicações , Cálculos Ureterais/patologia , Procedimentos Cirúrgicos Urológicos/métodos
7.
J Mater Chem B ; 1(23): 2894-2903, 2013 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32260855

RESUMO

Halloysite, naturally occurring clay nanotubes, is described as an additive for functional polymer composites. Due to the empty tubular lumen capable of being loaded with chemically active agents, halloysite provides additional functions (drug delivery, antibiotic, flame-retardant, anticorrosion, and crack self-healing) to polymeric composites synergistically combined with enhanced tensile, impact and adhesive strength. Doping loaded clay nanotubes into a polymeric matrix provides a kind of ceramic "skeleton", and these "skeleton bones" are loaded with functional chemicals like real bones loaded with marrow. Tunable controlled release of active agents through synthesis of artificial nano-caps at the tube endings and halloysite lumen enlargement by selective etching allowed for tubular nanocontainers with chemicals release time from 10 to 200 h and a loading capacity of ca. 30 wt%. Halloysite is well mixable with polymers of high and medium polarities without any surface modification.

8.
J Colloid Interface Sci ; 406: 121-9, 2013 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-23806416

RESUMO

Halloysite clay has chemical structure similar to kaolinite but it is rolled in tubes with diameter of 50 nm and length of ca. 1000 nm. Halloysite exhibits higher adsorption capacity for both cationic and anionic dyes because it has negative SiO2 outermost and positive Al2O3 inner lumen surface; therefore, these clay nanotubes have efficient bivalent adsorbancy. An adsorption study using cationic Rhodamine 6G and anionic Chrome azurol S has shown approximately two times better dye removal for halloysite as compared to kaolin. Halloysite filters have been effectively regenerated up to 50 times by burning the adsorbed dyes. Overall removal efficiency of anionic Chrome azurol S exceeded 99.9% for 5th regeneration cycle of halloysite. Chrome azurol S adsorption capacity decreases with the increase of ionic strength, temperature and pH. For cationic Rhodamine 6G, higher ionic strength, temperature and initial solution concentration were favorable to enhanced adsorption with optimal pH 8. The equilibrium adsorption data were described by Langmuir and Freundlich isotherms.


Assuntos
Silicatos de Alumínio/química , Nanotubos , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Argila , Reutilização de Equipamento , Filtração/instrumentação , Concentração de Íons de Hidrogênio , Hidroxibenzoatos/isolamento & purificação , Caulim , Concentração Osmolar , Rodaminas/isolamento & purificação
9.
ACS Appl Mater Interfaces ; 5(10): 4464-71, 2013 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-23631341

RESUMO

Halloysite clay nanotubes loaded with corrosion inhibitors benzotriazole (BTA), 2-mercaptobenzimidazole (MBI), and 2-mercaptobenzothiazole (MBT) were used as additives in self-healing composite paint coating of copper. These inhibitors form protective films on the metal surface and mitigate corrosion. Mechanisms involved in the film formation have been studied with optical and electron microscopy, UV-vis spectrometry, and adhesivity tests. Efficiency of the halloysite lumen loading ascended in the order of BTA < MBT < MBI; consequently, MBI and MBT halloysite formulations have shown the best protection. Inhibitors were kept in the tubes buried in polymeric paint layer for a long time and release was enhanced in the coating defects exposed to humid media with 20-50 h, sufficient for formation of protective layer. Anticorrosive performance of the halloysite-based composite acrylic and polyurethane coatings have been demonstrated for 110-copper alloy strips exposed to 0.5 M aqueous NaCl for 6 months.

10.
ACS Nano ; 6(8): 7216-26, 2012 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-22838310

RESUMO

Halloysite clay tubes have 50 nm diameter and chemically different inner and outer walls (inner surface of aluminum oxide and outer surface of silica). Due to this different chemistry, the selective etching of alumina from inside the tube was realized, while preserving their external diameter (lumen diameter changed from 15 to 25 nm). This increases 2-3 times the tube lumen capacity for loading and further sustained release of active chemical agents such as metals, corrosion inhibitors, and drugs. In particular, halloysite loading efficiency for the benzotriazole increased 4 times by selective etching of 60% alumina within the tubes' lumens. Specific surface area of the tubes increased over 6 times, from 40 to 250 m(2)/g, upon acid treatment.


Assuntos
Óxido de Alumínio/química , Silicatos de Alumínio/química , Cristalização/métodos , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Argila , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Porosidade , Propriedades de Superfície
11.
ACS Appl Mater Interfaces ; 3(10): 4040-6, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21905653

RESUMO

Halloysite is naturally available clay mineral with hollow cylindrical geometry and it is available in thousands of tons. Silver nanorods were synthesized inside the lumen of the halloysite by thermal decomposition of the silver acetate, which was loaded into halloysite from an aqueous solution by vacuum cycling. Images of individual ca. 15 nm diameter silver nanorods and nanoparticles were observed with TEM. The presence of silver inside the tubes was also verified with STEM-EDX elemental mapping. Nanorods had crystalline nature with [111] axis oriented ~68° from the halloysite tubule main axis. The composite of silver nanorods encased in clay tubes with the polymer paint was prepared, and the coating antimicrobial activity combined with tensile strength increase was demonstrated. Coating containing up 5% silver loaded halloysite did not change color after light exposure contrary to the sample prepared with loading with unshelled silver nanoparticles. Halloysite tube templates have a potential for scalable manufacturing of ceramic encapsulated metal nanorods for composite materials.


Assuntos
Acetatos/química , Silicatos de Alumínio/química , Antibacterianos/química , Nanotubos/química , Compostos de Prata/química , Acetatos/farmacologia , Antibacterianos/farmacologia , Argila , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Pintura/análise , Tamanho da Partícula , Compostos de Prata/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
12.
ACS Appl Mater Interfaces ; 1(7): 1437-43, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20355946

RESUMO

Halloysite clay nanotubes were investigated as a tubular container for the corrosion inhibitor benzotriazole. Halloysite is a naturally occurring cylindrical clay mineral with an internal diameter in the nanometer range and a length up to several micrometers, yielding a high-aspect-ratio hollow tube structure. Halloysite may be used as an additive in paints to produce a functional composite coating material. A maximum benzotriazole loading of 5% by weight was achieved for clay tubes of 50 nm external diameters and lumen of 15 nm. Variable release rates of the corrosion inhibitor were possible in a range between 5 and 100 h, as was demonstrated by formation of stoppers at tube openings. The anticorrosive performance of the sol-gel coating and paint loaded with 2-5% of halloysite-entrapped benzotriazole was tested on copper and on 2024-aluminum alloy by direct exposure of the metal plates to corrosive media. Kinetics of the corrosion spot formation at the coating defects was analyzed by the scanning vibrating electrode technique, and an essential damping of corrosion development was demonstrated for halloysite-loaded samples.


Assuntos
Silicatos de Alumínio/química , Triazóis/química , Argila , Cobre/química , Corrosão , Concentração de Íons de Hidrogênio , Cinética , Teste de Materiais , Microscopia Eletrônica de Varredura/métodos , Nanopartículas/química , Nanotecnologia/métodos , Nanotubos/química , Propriedades de Superfície , Fatores de Tempo
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