RESUMO
The surface structures of self-assembled monolayers (SAMs) formed by the adsorption of pentachlorobenzenethiol (PCBT) molecules on Au(111) as a function of solution concentration were examined by means of scanning tunneling microscopy (STM) to understand the effect of concentration on the formation of ordered domains. STM imaging revealed that PCBT SAMs formed in a 0.01 or 1 mM ethanol solution at room temperature for 20 min contained small ordered domains in the range of several to 20 nm2 and disordered phases, while PCBT SAMs formed in a 0.1 mM ethanol solution were composed of long-range ordered domains in the range of 20 to 50 nm2, which can be assigned as a (4 x â3)R45 degrees packing structure. Interestingly, the bright aggregated domains stacked by π-π interactions between PCBT rings were usually observed around boundary regions of ordered domains. In addition, X-ray photoelectron spectroscopy measurements revealed that ordered PCBT SAMs on Au(111) were formed via the chemical interactions between the sulfur atom of PCBT and gold surface. Our results obtained here will be very useful in understanding the formation and structure of PCBT SAMs on gold surfaces.
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Clorobenzenos/química , Ouro/química , Compostos de Sulfidrila/química , Adsorção , SoluçõesRESUMO
Self-assembled monolayers (SAMs) were formed by the spontaneous adsorption of 4-fluorobenzenethiol (4-FBT) on Au(111) using both solution and ambient-pressure vapor deposition methods at room temperature. The surface structure and thermal desorption properties of 4-FBT SAMs were examined by scanning tunneling microscopy (STM) and thermal desorption spectroscopy (TDS). STM imaging showed that 4-FBT SAMs formed in solution at room temperature mainly contained disordered phase with gold adatom islands, while those formed by ambient-pressure vapor deposition had well-ordered phase, which can be described as a (2 x 2â13)R45 degrees structure. In addition, thermal desorption spectroscopy (TDS) measurements showed that strong desorption peak for parent mass fragment (m/z = 128, FC6H5SH+) for 4-FBT SAMs on Au(111) was observed at 460 K, as a result of hydrogen abstract reaction of chemisorbed thiolates during desorption.
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Ouro/química , Compostos de Sulfidrila/química , Microscopia de TunelamentoRESUMO
BACKGROUND: In children, the most significant cause of rhabdomyolysis or muscle breakdown is viral infection. However, there are no reports that norovirus, a gastroenteric virus that commonly infects children, specifically causes rhabdomyolysis. Here, we report the first pediatric case of norovirus-associated rhabdomyolysis. CASE PRESENTATION: The patient, a 2-year-old boy with fever, diarrhea, and vomiting, was referred to our hospital with dysstasia and transaminitis. He was diagnosed with rhabdomyolysis. Additionally, norovirus genogroup GII was detected from stool samples by real-time quantitative reverse transcription Polymerase Chain Reaction, and thereafter, the norovirus GII.4 variant was identified. CONCLUSION: However, the association between rhabdomyolysis and the isolated norovirus variant was not clarified. After treatment the patient recovered without renal failure or disseminated intravascular coagulation. Rhabdomyolysis is a disease for which there is a need for early detection and treatment. If abnormal posture or muscle weakness is observed during the course of gastroenteritis, blood and urinary tests should be performed to rule out rhabdomyolysis.
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Infecções por Caliciviridae/diagnóstico , Gastroenterite/diagnóstico , Norovirus/isolamento & purificação , Rabdomiólise/etiologia , Infecções por Caliciviridae/complicações , Pré-Escolar , Gastroenterite/complicações , Gastroenterite/virologia , Humanos , Masculino , Rabdomiólise/diagnósticoRESUMO
Molecular-scale surface structures of self-assembled monolayers (SAMs) prepared by the adsorption of pentafluorobenzenethiols (PFBT) and pentachlorobenzenethiols (PCBT) on Au(111) were investigated by scanning tunneling microscopy (STM). High-resolution STM imaging revealed that PFBT SAMs on Au(111) have long-range ordered domains with a row structure at room temperature, whereas PCBT SAMs have small ordered domains, with disordered domains as the main phase. This may reflect the larger diffusion barriers of PCBT molecules on Au(111) surfaces compared to PFBT molecules during SAM formation. The structural transitions of PCBT SAMs from the mixed phase containing disordered and ordered domains to the uniform ordered domains were observed at 50 degrees C depending on immersion time. The ordered packing structure of PCBT SAMs is an incommensurate (square root of 3 x square root of 10)R45 degrees structure, which differs from that of PFBT SAMs with a (2 x 5 square root of 13)R30 degrees structure. We found that a small modification in the chemical structures of aromatic rings using a halo-substituent strongly affects the self-assembly mechanism and packing structure of aromatic thiol SAMs on Au(111). Moreover, we demonstrated that highly ordered PCBT SAMs can be obtained at a solution temperature of 50 degrees C after immersion for 60 min.
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Holey gold: Highly selective aerobic oxidation of methanol over alkylamines was achieved with a reusable nanoporous gold (AuNPore) catalyst that was fabricated from a Au-Ag alloy. This excellent chemoselectivity enabled direct N-formylation of alkylamines from a mixture of methanol and amines. The remarkable catalytic activity was attributed to the synergistic effect between gold and the residual silver remaining in the AuNPore.
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The growth processes of self-assembled monolayers (SAMs) of two azobenzene disulfides formed on flat gold surfaces were studied to confirm the effect of the intermolecular interactions between azobenzene molecules on the light-triggered surface morphologies of the SAMs. Scanning tunneling microscopy (STM), atomic force microscopy (AFM), thermal desorption spectroscopy (TDS), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible (UV-vis) absorption spectroscopy were employed to study the SAMs and their growth processes. The SAMs studied were of bulky-substituted azobenzene disulfide (Et-2S), and nonsubstituted azobenzene disulfide (Me-2S), formed on a gold-covered substrate, and had a twisted and a planar structure, respectively. STM-based imaging of the initial stage of the self-assembly of the Et-2S molecules revealed that cleavage of the disulfide bond occurred on the gold surface, and phase-separated domains composed of azobenzenethiolate and dodecanethiolate were formed. Time-dependent AFM-based imaging illustrated the mechanism through which the Et-2S SAM grew-it was through the formation of dendritic aggregates and islands-eventually resulting in phase-separated domains with a wormlike structure. This wormlike structure showed noticeable changes in its surface morphology upon irradiation with UV and visible light. On the other hand, while the growth process for the Me-2S SAM was similar to that of the Et-2S SAM, the final Me-2S SAM had smooth domains whose morphology did not exhibit photoswitchability. The TD and XP spectra of the SAMs showed that the number of adsorbed Et-2S molecules reached a point of saturation after a 24 h long immersion while the number of Me-2S molecules increased even after a 336 h long immersion. Furthermore, the area occupied by the azobenzene moiety in the Et-2S SAM was constant regardless of the immersion time, whereas that in the Me-2S SAM decreased with the immersion time. These results indicated that the strength of the interactions between the azobenzene molecules significantly influenced the aggregate-forming ability in SAMs.
Assuntos
Compostos Azo/química , Luz , Adsorção , Dissulfetos/química , Ouro/química , Modelos Moleculares , Conformação Molecular , Compostos de Sulfidrila/química , Propriedades de SuperfícieRESUMO
The growth process, solvent effects, and thermal desorption behavior of octylthiocyanate [OTC, CH(3)(CH(2))(7)S-CN] self-assembled monolayers (SAMs) on Au(111) were characterized by scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and thermal desorption spectroscopy (TDS). To investigate their growth processes, octanethiol [OT, CH(3)(CH(2))(7)S-H] and OTC SAMs were prepared in 0.5 µM ethanol solution at room temperature as a function of immersion time: 10 min, 1 h, 2 h, and 24 h. STM imaging revealed that OT SAMs underwent a phase transition from the liquid phase containing striped-phase domains to the closely packed c(4 × 2) phase. OTC SAMs underwent a different phase transition from the liquid phase containing aggregated molecules to the disordered phase containing striped-phase domains. The adsorption amounts of OTC SAMs formed after immersion for 10 min and 24 h were measured to be 16% and 30% smaller than those of OT SAMs under the same conditions. STM and XPS results show that the growth kinetics of OTC SAMs on Au(111) are much slower than those of OT SAMs. Hexane resulted in OTC SAMs of higher structural quality than ethanol, DMF, or toluene. TDS measurements revealed that the relative desorption intensities of octanethiolate (C8S(+), monomer) and dioctyl disulfide (C8SSC8(+), dimer) to octanethiol (C8SH(+)) fragments for OTC SAMs were much weaker than those of OT SAMs. This is because desorption of monomers and dimers is strongly suppressed by low surface coverage of OTC SAMs, as revealed by STM observations.
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BACKGROUND: In 2009, the rate of thoracoscopic esophagectomy for esophageal cancer was about 20% in Japan. This low rate may be due to the difficulty in maintaining a good surgical field and the meticulous procedures that are required. The purpose of this study was to establish and evaluate a new procedure for performing a thoracoscopic esophagectomy while the patient is in a prone position using a preceding anterior approach to make the esophagectomy easier to perform. METHODS: We have performed thoracoscopic esophagectomy using our new procedure in 60 patients with esophageal cancer. Each patient was placed in a prone position and five trocars were inserted; only the left lung was ventilated and a pneumothorax was maintained. The esophagus was mobilized from the anterior structure during the first step and from the posterior structure during the second step. The lymph nodes around the esophagus were also dissected anteriorly and posteriorly. The patients were sequentially divided into two groups and their clinical outcomes were evaluated. RESULTS: The mean operative time for the thoracoscopic procedure for the latter 30 cases (203 min) was shorter than that for the former 30 cases (260 min) (P = 0.001). Among the 52 cases without pleural adhesion, the mean blood loss in the latter 26 cases (18 mL) was also less than that in the former 26 cases (40 mL) (P = 0.027). There were no conversions to a thoracotomy and no operative deaths in this series. Postoperative complications related to the thoracoscopic procedure occurred in 8 cases (27%) in the former group and in 4 cases (13%) in the latter group. CONCLUSIONS: Thoracoscopic esophagectomy with the patient in the prone position using a preceding anterior approach is a safe and feasible procedure. As experience performing the procedure increases, the performance of the procedure stabilizes. This method seems to make the esophagectomy easier to perform.
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Neoplasias Esofágicas/cirurgia , Esofagectomia/métodos , Toracoscopia/métodos , Perda Sanguínea Cirúrgica/mortalidade , Conversão para Cirurgia Aberta/mortalidade , Neoplasias Esofágicas/mortalidade , Esofagectomia/mortalidade , Feminino , Humanos , Excisão de Linfonodo/mortalidade , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/mortalidade , Decúbito Ventral , Toracoscopia/mortalidade , Resultado do TratamentoRESUMO
The Model Project for Child Death Review (CDR) was initiated in Japan, but parental consent is required for detailed investigations. We proposed an alternative method to review child deaths using death certificates and forensic autopsy results when parental consent is not provided. We extracted and reviewed death certificates for the deceased younger than 18 years from among all certificates submitted in Shiga Prefecture between 2015 and 2017. In addition, we analyzed autopsy records in cases that underwent forensic autopsy. The prevalence of each cause of death was compared among age groups. The situation and circumstances of unnatural deaths were analyzed in detail. Of 131 certificates, unnatural deaths accounted for 29.7 %. The prevalence of each cause of death significantly differed among age groups. Malignant disease and suicide were most common in school-aged children and congenital disease was most common in infants. Suicide was the leading cause of unnatural death, followed by suffocation, which was most common in infants. Situations where suffocation was reported included co-sleeping with the mother and breastfeeding. Despite parental consent not being obtained, the trends of regional child deaths and the circumstances of accidental deaths were clarified by the present method. However, the results of detailed investigation were lacking. This study provided basic information for implementing detailed methods and procedures for CDR at the governmental level. To perform optimal CDR, legislation for collecting detailed information without parental consent is required.
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Asfixia , Suicídio , Lactente , Criança , Humanos , Autopsia , Atestado de Óbito , Causas de MorteRESUMO
The electronic structures of buried interfaces between an organic semiconductor, N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD) and metal surfaces of Au, Ag, Al and Ca were examined by the new experimental method that we have developed recently. In this method the energy levels at the organic/metal interface can be examined without changing the film thickness and related physical parameters e.g., the vacuum levels of the sample in contrast to the widely-used thickness-dependent photoemission experiments. The results were discussed in view of large interfacial dipole moment of the TPD and metal (Au and Ag) contacts.
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Metais/química , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Compostos Orgânicos/química , Semicondutores , Compostos de Sulfidrila/química , Teste de Materiais , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
Self-assembled monolayers (SAMs) formed by the adsorption of 4-fluorobenzenethiol (4-FBT) and 4-fluorobenzenemethanethiol (4-FBMT) on Au(111) were examined by scanning tunneling microscopy (STM) to understand the effect of a flexible methylene spacer between the sulfur head-group and phenyl group and the effect of solution temperature on the formation and structure of the SAMs. Although the adsorption of 4-FBT on Au(111) at room temperature for 24 h generated only disordered phase SAMs containing gold adatom islands, 4-FBT at 75 degrees C for 2 h formed mixed SAMs: disordered phases and ordered (2 x 12â(2))R10 degrees superlattice with a rectangular unit cell containing six adsorbed molecules. On the other hand, SAMs formed from 4-FBMT, with a methylene spacer, at room temperature for 24 h on Au(111) had irregularly ordered phases containing uniformly distributed VIs with lateral dimensions of 2-5 nm; SAMs formed from 4-FBMT at 75 degrees C for 2 h were composed of slightly improved ordered phases and larger VIs with lateral dimensions of 5-12 nm as a result of Ostwald ripening. From this study, we found that the methylene spacer plays an important role in controlling the structure of SAMs formed from p-substituted fluorinated aromatic thiols.
RESUMO
The surface structure and adsorption conditions of biphenylthiol (BPT) self-assembled monolayers (SAMs) on Au(111) were examined using scanning tunneling microscopy (STM) and X-ray photoelectron microscopy (XPS). STM imaging revealed that the structural order of BPT SAMs formed in a 0.01 mM ethanol solution at 60 degrees C decreases with increasing immersion time. Interestingly, BPT SAMs formed after 30 min have unique ordered domains containing well-ordered (square root of 3 x square root of 3)R30 degrees structures and bright rows that are connected by small aggregated domains with a periodicity of approximately 10 angstroms, results that have never been observed for other thiol SAM systems. Distances between the bright rows were 20-35 angstroms. The bright small domains contained five or six BPT molecules each, which may have originated from differences in the adsorption orientations of biphenyl groups that were induced by localized interactions between them. XPS measurements for BPT SAMs on Au(111) showed the two sulfur peaks at 161.2 and 162.2 eV, implying the formation of chemisorbed monolayers. Our results are anticipated to be useful for understanding the formation and structure of BPT SAMs on gold surfaces.
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Compostos de Bifenilo/química , Cristalização/métodos , Ouro/química , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Compostos de Sulfidrila/química , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
The formation and surface structure of pentafluorobenzenethiol (PFBT) self-assembled monolayers (SAMs) on Au(111) formed under various experimental conditions were examined by means of scanning tunneling microscopy (STM). Although it is well known that PFBT molecules on metal surfaces do not form ordered SAMs, we clearly revealed for the first time that the adsorption of PFBT on Au(111) at 75 degrees C for 2 h yields long-range, well-ordered self-assembled monolayers having a (2 x 5 square root(13))R30 degrees superlattice. Our results will provide new insight into controlling the structural order of PFBT SAMs, which will be very useful in precisely tailoring the interface properties of metal surfaces in electronic devices.
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When hydrogen atoms slowly diffuse into a metastable structure, a coherence length of thin TiZrNi quasicrystal metallic ribbons is increased. Improved atomic order with addition of hydrogen is an uncommon phenomenon in metals, and may reflect the unordinary structural property of quasicrystals. Metastable TiZrNi quasicrystals prepared by rapid quenching of molten ingots were hydrogenated in a low pressure of hydrogen (lower than 1000 Torr) at high temperature. After completion of the pressure-composition-temperature measurements between 200 to 300 degrees C, X-ray diffraction data revealed that the full width at half maximum values of the diffraction peaks were decreased suggesting that the quasicrystal phase may stabilized by hydrogen inclusion. Annealing of the same sample at 200 degrees C without hydrogen yields no change of the relative intensity of diffraction peaks.
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A new computational method for the detection of virus particles in transmission electron microscopy (TEM) images is presented. Our approach is to use a convolutional neural network that transforms a TEM image to a probabilistic map that indicates where virus particles exist in the image. Our proposed approach automatically and simultaneously learns both discriminative features and classifier for virus particle detection by machine learning, in contrast to existing methods that are based on handcrafted features that yield many false positives and require several postprocessing steps. The detection performance of the proposed method was assessed against a dataset of TEM images containing feline calicivirus particles and compared with several existing detection methods, and the state-of-the-art performance of the developed method for detecting virus was demonstrated. Since our method is based on supervised learning that requires both the input images and their corresponding annotations, it is basically used for detection of already-known viruses. However, the method is highly flexible, and the convolutional networks can adapt themselves to any virus particles by learning automatically from an annotated dataset.
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Infecções por Caliciviridae/virologia , Calicivirus Felino/isolamento & purificação , Processamento de Imagem Assistida por Computador/métodos , Microscopia Eletrônica de Transmissão , Animais , Calicivirus Felino/ultraestrutura , Gatos , Aprendizado de Máquina , Redes Neurais de Computação , Vírion/isolamento & purificação , Vírion/ultraestruturaRESUMO
Surface structures of tolanethioacetate (TTA) self-assembled monolayers (SAMs) on Au(111), formed in a 0.5mM N,N'-dimethylformamide (DMF) solution, were investigated as a function of solution temperature by scanning tunneling microscopy (STM). The STM study revealed that thioacetyl-terminated TTA molecules on Au(111) did not form ordered SAMs at room temperature and 80 degrees C, whereas the adsorption of TTA molecules on Au(111) at a solution temperature of 50 degrees C led to the formation of two mixed phases: a disordered phase and a unique ordered phase, consisting rod-like domains, which can be described as a ( radical6x radical13)15 degrees superstructure. From this study, it was demonstrated that solution temperature is a key factor controlling the two-dimensional SAM structure of TTA molecules.
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Hybrid CPbX3 (C: Cs, CH3 NH3 ; X: Br, I) perovskites possess excellent photovoltaic properties but are highly toxic, which hinders their practical application. Unfortunately, all Pb-free alternatives based on Sn and Ge are extremely unstable. Although stable and non-toxic C2 ABX6 double perovskites based on alternating corner-shared AX6 and BX6 octahedra (A=Ag, Cu; B=Bi, Sb) are possible, they have indirect and wide band gaps of over 2â eV. However, is it necessary to keep the corner-shared perovskite structure to retain good photovoltaic properties? Here, we demonstrate another family of photovoltaic halides based on edge-shared AX6 and BX6 octahedra with the general formula Aa Bb Xx (x=a+3 b) such as Ag3 BiI6 , Ag2 BiI5 , AgBiI4 , AgBi2 I7 . As perovskites were named after their prototype oxide CaTiO3 discovered by Lev Perovski, we propose to name these new ABX halides as rudorffites after Walter Rüdorff, who discovered their prototype oxide NaVO2 . We studied structural and optoelectronic properties of several highly stable and promising Ag-Bi-I photovoltaic rudorffites that feature direct band gaps in the range of 1.79-1.83â eV and demonstrated a proof-of-concept FTO/c-m-TiO2 /Ag3 BiI6 /PTAA/Au (FTO: fluorine-doped tin oxide, PTAA: poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], c: compact, m: mesoporous) solar cell with photoconversion efficiency of 4.3 %.
Assuntos
Bismuto/química , Compostos de Cálcio/química , Fontes de Energia Elétrica , Halogênios/química , Óxidos/química , Prata/química , Energia Solar , Titânio/química , Chumbo/química , Modelos Moleculares , Conformação MolecularRESUMO
BACKGROUND: Plication of an esophageal hiatus during surgery for esophageal hiatal hernia is a common practice; however, a mesh may be used if the hiatus is markedly enlarged. Recently, various late complications occurring as a result of mesh-induced esophageal and/or gastric wall injuries have been reported. CASE PRESENTATION: A 71-year-old woman presented at a neighborhood clinic in November 2010 with chief complaints of respiratory distress on exertion and heartburn. She was diagnosed as having a large esophageal hiatal hernia and was treated at our hospital using a laparoscopic Toupet fundoplication with mesh repair of the esophageal hiatus. Two years and 1 month after the operation, the patient complained of a bowel obstruction. An upper gastrointestinal endoscopy revealed that part of the mesh had extruded into the esophageal lumen, resulting in ulceration and stricture of the esophageal wall. Endoscopic balloon dilatation failed to improve the esophageal stricture. In July 2012, the patient underwent a lower esophagectomy with proximal gastrectomy and was discharged on the 25th hospital day. CONCLUSIONS: We experienced a rare case requiring surgical treatment for a mesh-induced esophageal wall injury after surgery for a giant esophageal hiatal hernia. The selection of a soft, durable mash and its firm securement at a position distant from the gastrointestinal wall may be important to avoid late esophageal wall injury.
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Increased oxidative stress under hyperglycemia may contribute to progressive deterioration of peripheral insulin sensitivity. In this study, we investigated whether gliclazide, a second-generation sulfonylurea, can protect 3T3L1 adipocytes from insulin resistance induced by oxidative stress, and whether gliclazide can restore insulin-stimulated glucose transporter 4 (GLUT4) translocation under oxidative stress. We incubated 3T3L1 adipocytes in hydrogen peroxide to produce oxidative stress, then administered various concentrations of gliclazide, N-acetylcystein (NAC), or glibenclamide. Cells treated with these drugs were next exposed to insulin, subsequent glucose uptake was measured, and the insulin-stimulated GLUT4 translocation was monitored in living cells. We found that hydrogen peroxide treatment alone suppressed glucose uptake by insulin stimulation to 65.9%+/-7.8% of the corresponding controls (P<.01). However, addition of 0.1 to 10 micromol/L gliclazide to hydrogen peroxide-treated cells dose-dependently restored glucose uptake, with 5 micromol/L gliclazide significantly restoring glucose uptake to 93.3+/-6.6% (P<.01) even under hydrogen peroxide. Treatment with the known anti-oxidant NAC also dose-dependently (0.1-10 mmol/L) restored insulin-induced glucose uptake in the presence of hydrogen peroxide. However, glibenclamide (0.1-10 micromol/L), another second-generation sulfonylurea, failed to improve glucose uptake. Similarly, treatment with 5 micromol/L gliclazide or 10 mmol/L NAC significantly overcome the reduction in insulin-stimulated GLUT4 translocation by hydrogen peroxide (P<.01), whereas 5 micromol/L glibenclamide did not. Therefore our data regarding gliclazide further characterize its mechanism of hypoglycemic effect: the observed improvements in insulin sensitivity and in GLUT4 translocation indicate that gliclazide counters the hydrogen peroxide-induced insulin resistance in 3T3L1 adipocytes and also would further augment the hypoglycemic effect of this drug as insulinotropic sulfonylurea.