Crystallization behavior and crystal properties of lactose as affected by lactic, citric, or phosphoric acid.

The presence of acids in a lactose-containing system can affect its crystallization. The crystallization kinetics of lactose solutions were investigated as affected by lactic, citric, or phosphoric acid at a concentration of 0.05, 1, or 4% (wt/wt) as compared with that of pure lactose. The crystallization behavior of lactose was affected differently by the presence of all 3 acids and was mostly concentration dependent. The presence of 1 and 4% citric or phosphoric acid reduced the crystal yield significantly (≥18%) as compared with that of pure lactose (∼82%). Thermographic analysis of lactose crystals showed that the presence of 1% lactic, 0.05 and 1% citric, and 4% phosphoric acids in the lactose solutions induced the formation of amorphous lactose. X-Ray diffraction analysis revealed that the lactose crystallized mainly into α-lactose monohydrate, stable anhydrous α-lactose, and anhydrous crystals containing α-lactose and ß-lactose in a molar ratio of 5:3 and 4:1. Average size of the lactose particles, comprising of several crystallites, declined depending on the type of the acids and their concentration, but size of a single crystallite was not altered. The findings suggested that the lactose crystallization and crystal properties are governed by the lactose-water interactions, which can be influenced by the presence of acids in a concentration-dependent manner.

Dental Fluorosis Treatment Can Improve the Individuals' OHRQoL? Results from a Randomized Clinical Trial.

This study aimed to evaluate the effect on oral health-related quality of life (OHRQoL) of two treatment protocols for dental fluorosis in individuals enrolled in a randomized clinical trial. Seventy volunteers, who lived in a fluorosis endemic area in Brazil, and had at least four maxillary anterior teeth showing fluorosis with a Thylstrup and Fejerskov index from 1 to 7, were randomized into two treatment groups (n= 35): GI- enamel microabrasion; or GII- microabrasion associated with at-home bleaching. Microabrasion was performed using 37% phosphoric acid and pumice, and at-home tooth bleaching with 10% carbamide peroxide in a tray. Volunteers completed a questionnaire at baseline and 1-month post treatment to assess changes in OHRQoL, using the Oral Impact on Daily Performance (OIDP). Differences in overall impact scores between and within treatment groups were analyzed with Wilcoxon (within) and Mann-Whitney (between) tests. Changes in performance scores were analyzed using Wilcoxon tests (a< 0.05). One month after treatment, subjects reported improvement in OHRQoL. Both groups showed lower OIDP scores (p< 0.001), but there was no difference between them. Eating, cleaning teeth, smiling and emotional state performance scores were lower after treatment for the whole sample. In conclusion, the treatment with microabrasion improved the OHRQoL in this sample of individuals living in a fluorosis endemic area regardless of the addition of at-home bleaching.

Dental fluorosis treatment can improve the individuals' ohrqol? results from a randomized clinical trial

Abstract This study aimed to evaluate the effect on oral health-related quality of life (OHRQoL) of two treatment protocols for dental fluorosis in individuals enrolled in a randomized clinical trial. Seventy volunteers, who lived in a fluorosis endemic area in Brazil, and had at least four maxillary anterior teeth showing fluorosis with a Thylstrup and Fejerskov index from 1 to 7, were randomized into two treatment groups (n= 35): GI- enamel microabrasion; or GII- microabrasion associated with at-home bleaching. Microabrasion was performed using 37% phosphoric acid and pumice, and at-home tooth bleaching with 10% carbamide peroxide in a tray. Volunteers completed a questionnaire at baseline and 1-month post treatment to assess changes in OHRQoL, using the Oral Impact on Daily Performance (OIDP). Differences in overall impact scores between and within treatment groups were analyzed with Wilcoxon (within) and Mann-Whitney (between) tests. Changes in performance scores were analyzed using Wilcoxon tests (a< 0.05). One month after treatment, subjects reported improvement in OHRQoL. Both groups showed lower OIDP scores (p< 0.001), but there was no difference between them. Eating, cleaning teeth, smiling and emotional state performance scores were lower after treatment for the whole sample. In conclusion, the treatment with microabrasion improved the OHRQoL in this sample of individuals living in a fluorosis endemic area regardless of the addition of at-home bleaching.

Resumo Este estudo teve como objetivo avaliar o efeito na qualidade de vida relacionada à saúde bucal (QVRSB) de dois protocolos de tratamento para fluorose dentária, em indivíduos incluídos em um ensaio clínico randomizado. Setenta voluntários, os quais viviam em uma área de fluorose endêmica no Brasil, e que possuíam pelo menos quatro dentes ântero-superiores com índice de Thylstrup e Fejerskov de 1 a 7, foram randomizados em dois grupos de tratamento (n= 35): GI- microabrasão de esmalte; ou GII- microabrasão associada com clareamento caseiro. A microabrasão foi realizada com ácido fosfórico 37% e pedra pomes e, o clareamento caseiro com peróxido de carbamida 10% e uso de moldeira. Os voluntários responderam um questionário antes e 1 mês após o tratamento, visando avaliar mudanças na QVRSB através do instrumento Oral Impact on Daily Performance (OIDP). Diferenças nos escores de impacto geral entre e nos mesmos grupos de tratamento foram analisadas através dos testes Wilcoxon (mesmo grupo) e Mann-Whitney (entre grupos), respectivamente. Alterações no escores dos domínios foram analisadas usando o teste Wilcoxon (a<0.05). Um mês após o tratamento, os indivíduos relataram melhora na QVRSB. Ambos os grupos apresentaram menores escores do OIDP (p<0,001), sem diferença entre eles. Os escores dos domínios comer, limpar os dentes, sorrir e estado emocioal diminuíram após o tratamento para toda a amostra. Concluiu-se que o tratamento com microabrasão melhorou a QVRSB de indivíduos vivendo em uma área de fluorose endêmica independentemente da associação com o clareamento caseiro.

177Lu-Labeled Phosphoramidate-Based PSMA Inhibitors: The Effect of an Albumin Binder on Biodistribution and Therapeutic Efficacy in Prostate Tumor-Bearing Mice.

Prostate-specific membrane antigen (PSMA) continues to be an active biomarker for small-molecule PSMA-targeted imaging and therapeutic agents for prostate cancer and various non-prostatic tumors that are characterized by PSMA expression on their neovasculature. One of the challenges for small-molecule PSMA inhibitors with respect to delivering therapeutic payloads is their rapid renal clearance. In order to overcome this pharmacokinetic challenge, we outfitted a 177Lu-labeled phosphoramidate-based PSMA inhibitor (CTT1298) with an albumin-binding motif (CTT1403) and compared its in vivo performance with that of an analogous compound lacking the albumin-binding motif (CTT1401). The radiolabeling of CTT1401 and CTT1403 was achieved using click chemistry to connect 177Lu-DOTA-N3 to the dibenzocyclooctyne (DBCO)-bearing CTT1298 inhibitor cores. A direct comparison in vitro and in vivo performance was made for CTT1401 and CTT1403; the specificity and efficacy by means of cellular uptake and internalization, biodistribution, and therapeutic efficacy were determined for both compounds. While both compounds displayed excellent uptake and rapid internalization in PSMA+ PC3-PIP cells, the albumin binding moiety in CTT1403 conferred clear advantages to the PSMA-inhibitor scaffold including increased circulating half-life and prostate tumor uptake that continued to increase up to 168 h post-injection. This increased tumor uptake translated into superior therapeutic efficacy of CTT1403 in PSMA+ PC3-PIP human xenograft tumors.

Bond strengths of brackets bonded to enamel surfaces conditioned with femtosecond and Er:YAG laser systems.

The aim of this study was to compare femtosecond and Er:YAG laser systems with regard to enamel demineralization and bracket bond strength. Human-extracted premolars were randomized to three groups (n = 17) depending on the conditioning treatment used for the buccal surfaces: 37 % orthophosphoric acid, Er:YAG laser etching (MSP mode 120 mJ, 10 Hz, 1.2 W), and femtosecond laser etching (0.4 W, 800 nm, 90 fs/pulse, 1 kHz). Metal brackets were bonded with Transbond XT to the conditioned surfaces and light cured for 20 s. The samples were thermocycled (5000 cycles, 5-55 °C) and subjected to shear bond strength (SBS) testing using a universal testing machine. Failure types were analyzed under an optical stereomicroscope and SEM. The adhesive remnant index (ARI) was evaluated to assess residual adhesive on the enamel surface. The results revealed no significant differences in SBS between the Er:YAG laser (7.2 ± 3.3 MPa) and acid etching groups (7.3 ± 2.7 MPa; p < 0.05), whereas a significant difference was observed between the femtosecond laser etching group (3.3 ± 1.2 MPa) and the other two groups (p < 0.01). ARI scores were significantly different among the three groups. The results of our study suggest that laser conditioning with an Er:YAG system results in successful etching, similar to that obtained with acid. The sole use of a femtosecond laser system may not provide an adequate bond strength at the bracket-enamel interface.

Evaluation of New Fluorescent Lipophosphoramidates for Gene Transfer and Biodistribution Studies after Systemic Administration.

The objective of lung gene therapy is to reach the respiratory epithelial cells in order to deliver a functional nucleic acid sequence. To improve the synthetic carrier's efficacy, knowledge of their biodistribution and elimination pathways, as well as cellular barriers faced, depending on the administration route, is necessary. Indeed, the in vivo fate guides the adaptation of their chemical structure and formulation to increase their transfection capacity while maintaining their tolerance. With this goal, lipidic fluorescent probes were synthesized and formulated with cationic lipophosphoramidate KLN47 (KLN: Karine Le Ny). We found that such formulations present constant compaction properties and similar transfection results without inducing additional cytotoxicity. Next, biodistribution profiles of pegylated and unpegylated lipoplexes were compared after systemic injection in mice. Pegylation of complexes led to a prolonged circulation in the bloodstream, whereas their in vivo bioluminescent expression profiles were similar. Moreover, systemic administration of pegylated lipoplexes resulted in a transient liver toxicity. These results indicate that these new fluorescent compounds could be added into lipoplexes in small amounts without perturbing the transfection capacities of the formulations. Such additional properties allow exploration of the in vivo biodistribution profiles of synthetic carriers as well as the expression intensity of the reporter gene.

Effect of Selective Etch on the Bond Strength of Composite to Enamel Using a Silorane Adhesive.

An improvement in bond strength to enamel has been demonstrated with the use of phosphoric acid prior to bonding with self-etch methacrylate-based adhesive agents. No research has evaluated the effect of phosphoric-acid etching of enamel with a newer self-etch silorane adhesive. The purpose of this study was to evaluate the shear-bond strength of composite to enamel using the self-etch silorane adhesive compared to other self-etching methacrylate-based adhesives, with or without a separate application of phosphoric acid. Bovine incisors were sectioned using a diamond saw and mounted in plastic pipe. The bonding agents were applied to flattened enamel surfaces with or without the application of 35% phosphoric acid. The bonded tooth specimens were inserted beneath a mold, and composite was placed incrementally and light cured. The specimens were stored for 24 hours and six months in water and tested in shear. Data were analyzed with a three-way analysis of variance (ANOVA) to evaluate the effects of surface treatment, adhesive agent, or time on the bond strength of composite to bovine enamel (α=0.05). Significant differences were found between the groups based on surface treatment (p<0.01) or adhesive agent (p<0.01), but not on time (p=0.19), with no significant interactions (p>0.14). Phosphoric-acid etching of bovine enamel significantly increased the bond strength of the self-etch methacrylate and the silorane adhesives. The methacrylate-based adhesives had significantly greater bond strength to enamel than the silorane adhesive.

Does active application of universal adhesives to enamel in self-etch mode improve their performance?

OBJECTIVES: To evaluate the effect of adhesion strategy on the enamel microshear bond strengths (µSBS), etching pattern, and in situ degree of conversion (DC) of seven universal adhesives. METHODS: 84 extracted third molars were sectioned in four parts (buccal, lingual, proximal) and divided into 21 groups, according to the combination of the main factors adhesive (AdheSE Universal [ADU], All-Bond Universal [ABU], Clearfil Universal [CFU], Futurabond U [FBU], G-Bond Plus [GBP], Prime&Bond Elect (PBE), and Scotchbond Universal Adhesive [SBU]), and adhesion strategy (etch-and-rinse, active self-etch, and passive self-etch). Specimens were stored in water (37°C/24h) and tested at 1.0mm/min (µSBS). Enamel-resin interfaces were evaluated for DC using micro-Raman spectroscopy. The enamel-etching pattern was evaluated under a field-emission scanning electron microscope (direct and replica techniques). Data were analyzed with two-way ANOVA and Tukey's test (α=0.05). RESULTS: Active self-etch application increased µSBS and DC for five out of the seven universal adhesives when compared to passive application (p<0.001). A deeper enamel-etching pattern was observed for all universal adhesives in the etch-and-rinse strategy. A slight improvement in etching ability was observed in active self-etch application compared to that of passive self-etch application. Replicas of GBP and PBE applied in active self-etch mode displayed morphological features compatible with water droplets. The DC of GBP and PBE were not affected by the application/strategy mode. CONCLUSIONS: In light of the improved performance of universal adhesives when applied actively in SE mode, selective enamel etching with phosphoric acid may not be crucial for their adhesion to enamel. CLINICAL SIGNIFICANCE: The active application of universal adhesives in self-etch mode may be a practical alternative to enamel etching in specific clinical situations.

Suicide case due to phosphoric acid ingestion: case report and review of literature.

Ingesting caustic substances represents a common event which may result in serious injuries of the gastrointestinal system. Severity of injury depends on the type of ingested substance: Caustic burns are more frequently associated with acid ingestion and their severity depends on type, concentration, time of exposure, and amount of the ingested substance. We report a case of phosphoric acid ingestion leading to death in a patient with depressive disorder. While reports ingestion of other acids and organophosphates can be found in the literature, there are no reports detailing a death due to phosphoric acid ingestion. We hope that presenting the findings in this case can aid death investigators in future cases that may involve ingestion of such a substance. After autopsy pH, phosphate and calcium ions concentration in the blood were analyzed. The cause of death was due to systemic effects: metabolic acidosis, hypophosphatemia, hypocalcemia, and hyperkalemia.

Dinâmica da população de coliformes durante a compostagem automatizada de dejetos líquidos de suínos / Population dynamics during composting of fecal automated pig slurry

Microrganismos presentes em dejetos de suínos podem contaminar o meio ambiente. Embora a compostagem seja preconizada como um método eficiente para reduzir este potencial poluidor dos dejetos, existem poucas informações de pesquisa sobre tal processo. O presente trabalho teve o objetivo de avaliar a eficiência da compostagem automatizada dos dejetos líquidos de suínos (DLS) na redução da população de coliformes, usados como indicadores de poluição fecal. Os DLS foram adicionados periodicamente, durante 106 dias, em substrato constituído pela mistura, em partes iguais, de maravalha e serragem. Foram efetuadas 14 adições de DLS, e em cada adição as leiras de compostagem eram revolvidas por meio de uma máquina especialmente desenvolvida para este fim. Foram avaliados dois tratamentos com três repetições, sendo um com e outro sem adição de ácido fosfórico aos dejetos, até pH 6,0. A adição de ácido visou reduzir as perdas de N por volatilização de amônia (NH3) durante a compostagem. A avaliação da população de coliformes foi feita pela técnica do número mais provável (NMP), com uso do caldo Fluorocult, incubado a 37ºC por 24h e posterior leitura em luz ultravioleta. A população de coliformes fecais não foi afetada pela adição de ácido fosfórico. O processo de compostagem automatizada foi eficiente na redução de coliformes fecais, cuja população original passou de 4,2x1010 para 1,2 x 105 ao final da compostagem (156 dias) sem adição de ácido e de 3,8x1010 para 2,3x104 na compostagem com adição de ácido. Essa remoção de coliformes fecais, promovida pela compostagem automatizada dos dejetos líquidos de suínos, corresponde a 99,99 por cento...

Microorganisms present in pig manure can contaminate the environment. Although composting is recommended as an efficient method to reduce the pollution potential of waste, there is little research information on this process. This study aimed to evaluate the efficiency of automated composting of pig slurry (PS) in reducing the population of coliforms, used as fecal pollution indicators. The PS was added periodically during 106 days in substrate, with a mixture, in equal parts, of wood shavings and sawdust. There were 14 additions of PS and at each addition the compost windrows were revolved through a machine especially developed for this purpose. Two treatments with three replications were evaluated, one with and one without the addition of phosphoric acid to the slurry up to pH 6.0. The acid addition aimed to reduce N losses through the volatilization of ammonia (NH3) during composting. Coliforms were evaluated by the technique of most probable number (MPN) using the Fluorocult broth, incubated at 37 ° C for 24 h and subsequent reading in ultra violet light. The population of fecal coliforms was not affected by the addition of phosphoric acid. The automated composting process was effective in reducing faecal coliforms, whose original population decreased from 4.2 x 1010 to 1.2 x 105 at the end of composting (156 days) without addition of acid and from 3.8 x1010 to 2,3 x104 in compost with added acid. This removal of faecal coliforms, promoted by automated composting of pig slurry, corresponds to 99.99 percent...

Acid etching concentration as a strategy to improve the adhesive performance on Er:YAG laser and bur-prepared demineralized enamel.

OBJECTIVE: This study investigated the effect of phosphoric acid concentration on microshear bond strength (µSBS) of an etch-and-rinse adhesive system to demineralized irradiated enamel. BACKGROUND DATA: Er:YAG laser irradiation may increase acid resistance of enamel; however, its use is associated with reduced bonding effectiveness. MATERIALS AND METHODS: Three experimental etching agents and one bonding agent were fabricated. Enamel pretreatment was tested in two levels (bur and laser) and phosphoric acid was tested in four levels (control and at 35, 45, or 55%). Commercially available phosphoric acid and a bonding agent were used as control. Enamel samples were submitted to a pH-cycling model to induce demineralization. Half of the exposed demineralized enamel area was prepared with diamond bur and half was prepared with an Er:YAG laser (λ=2.94 µm, 300 mJ, 2 Hz). Specimens were randomly allocated to receive different acid etching concentrations and either the experimental or the commercial adhesive system. Microshear bond strength and the adhesive remnant index (ARI) scores were determined. µSBS's data were evaluated by two way analysis of variance (ANOVA) and Tukey's test. Kruskal-Wallis followed by Dunn's method and Mann-Whitney test were used for ARI comparisons (α=5%). RESULTS: For µSBS, no significant difference among the groups was found, either for phosphoric acid concentration or surface preparation. For ARI scores, statistically higher resin retention was found for lased groups (p<0.001). CONCLUSIONS: The increase of phosphoric acid concentration did not impair bond strength regardless of surface preparation; however, increased retention was found when demineralized enamel was prepared with laser.

The effect of different enamel surface treatments on microleakage of fissure sealants.

OBJECTIVE: The aim of this study was to evaluate the effects of different techniques of surface treatment on the microleakage of fissure sealants in permanent molar teeth in vitro. MATERIALS AND METHODS: 96 extracted impacted human third molars were randomly divided into 8 surface treatment groups (n=12/group) as 1. Er: YAG laser ; (Fidelis II, Fotona, Ljubljana, Slovenia) (125 mj, 20Hz) ; 2. Er: YAG laser + 37% H3PO4 (15s) ; 3. ER: AG laser + 37% H3PO4+Prime&Bond NT ; 4. Er: YAG laser + G Bond ; 5. Er: YAG laser + Prime&Bond NT ; 6. 37% H3PO4 ; 7. 37% H3PO4 + Prime&Bond NT ; 8. G Bond. Sealant material (Clinpro, 3M ESPE, Seefeld, Germany), was applied into the fissures and light-cured for 20s with LED (Bluephase C5, Ivoclar-Vivadent, Schaan, Liechtenstein). Specimens were subjected to thermocycling (1000×, 5-55°C, dwell time: 15s) and immersed in 0.5% basic fuchsin solution for 24h at 37°C. The samples were sectioned and scored on a 3 point rating scale using a light microscope with a magnification of ×20. One-way analysis of variance was used to analyze data. Multiple comparisons were analyzed using Bonferroni test (p=0.05). RESULTS: Er:YAG laser showed the highest microleakage scores whereas Er YAG laser + 37% H3PO4 showed the lowest. Although 37% H3PO4 group showed higher scores than Er:YAG laser + 37% H3PO4, the difference was not statistically significant. CONCLUSION: Etching fissures with phosphoric acid is sufficient prior to fissure sealant application.

Effects of phosphoric acid concentration and etching duration on enamel and dentin tissues of uremic patients receiving hemodialysis: an AFM study.

PURPOSE: Using atomic force microscopy (AFM), the purpose was to investigate the effect of phosphoric acid (H3PO4) concentration and etching duration on surface roughness (Ra) and micromorphology of enamel and dentin substrates of uremic patients receiving hemodialysis. MATERIALS AND METHODS: Sixty-three enamel and dentin slabs were prepared from 42 sound natural molars collected from uremic patients under hemodialysis and mechanically polished up to 4000-grit roughness. Nine slabs of each substrate were not etched (control group). The remaining slabs were divided into two experimental groups (n = 27) according to etchant concentration (37% or 42%). In each group, 9 specimens were etched for 15, 30, and 60 s. The surface morphology of the control and test specimens was examined by AFM operated in "contact" mode. The obtained Ra was subjected to statistical analysis. RESULTS: Statistical analysis showed that increasing the duration of acid application (irrespective of acid concentration and type of substrate) significantly increased the amount of Ra. H3PO4 at a concentration of 42% was more effective at producing Ra than was H3PO4 at 37% for all 3 application times. The Ra quantity produced by H3PO4 at 42% was time specific, with 15 s being significantly less effective than 30 or 60 s. However, 60 s was significantly better than 30. CONCLUSION: The findings of this study support the use of 42% H3PO4 for etching uremic hard tooth tissues for 60 s.

Effect of organic acids and mannanoligosaccharide on excretion of Salmonella typhimurium in experimentally infected growing pigs.

The effect of organic acids and mannanoligosaccharide addition to the diet was assessed in pigs orally inoculated with Salmonella typhimurium. Forty-six growers were distributed among four treatments: Basal Diet (BD); BD+encapsulated organic acids; BD+free organic acids; BD+mannanoligosaccharide. Seroconversion was monitored, and feces and tissue samples were tested for Salmonella isolation. No treatment prevented the carrier state, but a tendency of lower fecal excretion was observed in the group treated with mannanoligosaccharide.

Evaluation of the efficacy of glyphosate plus urea phosphate in the greenhouse and the field.

BACKGROUND: Glyphosate is a non-selective, foliar-applied, systemic herbicide that kills weeds by inhibiting the synthesis of 5-enolpyruvylshikimate-3-phosphate synthase. Urea phosphate (UPP), made by the reaction of urea with phosphoric acid, was applied as an adjuvant for glyphosate in this study. Experiments in the greenhouse and the field were conducted to determine the effects of UPP by comparing the efficacies of glyphosate plus UPP, glyphosate plus 1-aminomethanamide dihydrogen tetraoxosulfate (AMADS) and Roundup. RESULTS: The optimum concentration of UPP in glyphosate solution was 2.0% when UPP was used as an adjuvant. The ED50 values for glyphosate-UPP were 291.7 and 462.4 g AI ha(-1) in the greenhouse and the field respectively, while the values for Roundup were 448.2 and 519.6 g AI ha(-1). The ED50 values at 2 weeks after treatment (WAT) and 3 WAT were lowered when UPP was used as an adjuvant in the greenhouse and field study, and the glyphosate+UPP was absorbed over a 2 week period. UPP may increase the efficacy by causing severe cuticle disruption or accelerating the initial herbicide absorption. The result also showed that UPP could reduce the binding behaviour of Ca2+ to glyphosate. CONCLUSION: The application of UPP as an adjuvant could increase the efficacy of glyphosate and make it possible to achieve effective control of weeds with glyphosate at lower dose. Moreover, UPP showed less causticity to spraying tools and presented less of a health hazard. Therefore, UPP is accepted as being a new, effective and environmentally benign adjuvant for glyphosate.

Effect of various concentrations of sodium hypochlorite on primary dentin: an in vitro scanning electron microscopic study.

BACKGROUND: Sodium hypochlorite solutions have been evaluated for their effects in bonding procedures as they are found to deplete or remove the organic portion of the dentin, particularly the collagen fibrils. The aim of this in vitro study was to assess and compare the efficacies of 1%, 2.5%, 5% and 10% NaOCl at 30, 60 and 120s on etched primary dentin. METHODS: 84 primary anterior teeth were ground to expose a flat dentin area on the buccal surface. The specimens were divided into fourteen groups of six each based on the dentin surface treatment (35% phosphoric acid etching for 7 seconds-AE and/or NaOCl application), NaOCl solution concentrations (1%, 2.5%, 5% and 10%) and time of application (0, 30, 60 and 120s). Specimens were prepared for SEM and photomicrographs were taken of the surface and were scored against a five point scale, based on the smear layer and amount of collagen removed. The scores were submitted to Kruskal-Wallis and Mann Whitney tests. RESULTS: This study showed the presence of smear layer in the control group. The group treated with Acid Etchant showed a demineralized pattern of dentin with exposure of dentin tubules and collagen fibrils network on the intertubular and peritubular dentin which was not significantly different from the groups treated with 1% and 2.5% NaOCl. Groups treated with 5% NaOCI were not statistically different from each other the surface was corroded but collagen fibrils were not completely depleted. Groups treated with 10% NaOCl were not statistically different from each other and showed complete removal of collagen fibrils with wider tubular apertures and several secondary tubules on peritubular and intertubular dentin. CONCLUSION: Higher concentrations of NaOCl solutions (5% and 10%) produced significant changes in the etched primary dentin. The higher the concentration of the NaOCI solution, the lower can be the time for the application of the solution for the complete removal of collagen fibrils.

Deaths related to chemical burns.

The authors present a series of 6 deaths due to the uncommon cause of chemical burns. Of the 6 deaths due to chemical burns, 4 deaths were due to ingestion of a chemical, 1 death was caused by chemical burns of the skin, and 1 death resulted from rectal insufflation of a chemical. Seven additional cases where chemical burns may have been a contributing factor to the death or an incidental finding are also presented. Four cases are related to an incident involving chemical exposure during an industrial explosion. Three cases involve motor fuel burns of the skin. Two cases concern a plane crash incident, and 1 case involved a vehicular collision. Cases are derived from the records of the Dallas County Medical Examiner's Office and those of the authors' consultation practices. Each of the cases is presented, followed by a discussion of the various mechanisms of chemical injury.

String-like micellar nanoparticles formed by complexation of PEG-b-PPA and plasmid DNA and their transfection efficiency.

PURPOSE: To investigate the gene delivery efficiency of string-like PEG-b-PPA/DNA micellar nanoparticles in the liver after intravenous injection and intrabiliary infusion. METHODS: PEG-b-PPA/DNA micellar nanoparticles were prepared in aqueous solution through spontaneous self-assembly between plasmid DNA and PEG(10K)-b-PPA(4K) or PEG(10K)-b-PP(13K) polymer. The stability of these micellar nanoparticles in different physiological media was evaluated by monitoring the particle size change of micellar nanoparticles with dynamic light scattering (DLS). The transfection efficiency of string-like PEG-b-PPA/DNA micellar nanoparticles in the liver was examined and compared with that of PPA/DNA nanoparticles after intravenous and intrabiliary infusion. RESULTS: These PEG-b-PPA/DNA micellar nanoparticles exhibited unique string-like morphology under TEM. The stability of these string-like nanoparticles in salt-, serum- or bile- containing media was significantly improved compared with PPA/DNA nanoparticles. More importantly, these PEG-b-PPA/DNA nanoparticles mediated 10-fold higher transfection efficiency than PPA/DNA nanoparticles in rat liver when delivered via intrabiliary infusion. In addition, histopathological data revealed that the PEG-b-PPA/DNA nanoparticles induced minimal level of liver toxicity or damage. CONCLUSIONS: These string-like PEG-b-PPA/DNA micelles can mediate efficient transgene expression in the liver after bile duct infusion, and they have great potential to be used as effective gene carriers for liver-targeted gene delivery.

Shear bond strength of bonding to enamel with different laser irradiation distances.

The aim of this study was to investigate the shear bond strength of bonding to enamel following laser etching with the Er:YAG or Er,Cr:YSGG laser using different irradiation distances. Of 99 extracted human premolar teeth, 90 were divided equally into nine groups. In the control group (group A) the teeth were etched with 38% phosphoric acid. In the laser groups (groups B-I) the enamel surface of the teeth was laser-irradiated, groups B-E with the Er:YAG laser and groups F-I with the Er,Cr:YSGG laser at distances of 1, 2, 4 and 6 mm, respectively. The shear bond strengths were tested using a universal testing machine. The shear bond strengths associated with the Er:YAG laser at 4 and 6 mm and the Er,Cr:YSGG laser at 2, 4 and 6 mm were significantly less than the strengths obtained with the other irradiation distances (p<0.001). The Er:YAG laser at 1 mm and the Er,Cr:YSGG laser at 1 mm etched enamel in the same manner (p>0.05). This finding was confirmed by scanning electron microscopy examination. Irradiation distance did influence the strength of adhesion to enamel. The mean shear bond strengths and enamel surface etching obtained with the Er:YAG laser at 1 and 2 mm and the Er,Cr:YSGG laser at 1 mm were comparable to that obtained with acid etching.