Isolation and identification of a polyester-polyurethane degrading bacterium Bacillus altitudinis YX8-1 / 生物工程学报

Although polyurethane (PUR) plastics play important roles in daily life, its wastes bring serious environmental pollutions. Biological (enzymatic) degradation is considered as an environmentally friendly and low-cost method for PUR waste recycling, in which the efficient PUR-degrading strains or enzymes are crucial. In this work, a polyester PUR-degrading strain YX8-1 was isolated from the surface of PUR waste collected from a landfill. Based on colony morphology and micromorphology observation, phylogenetic analysis of 16S rDNA and gyrA gene, as well as genome sequence comparison, strain YX8-1 was identified as Bacillus altitudinis. The results of high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) showed that strain YX8-1 was able to depolymerize self-synthesized polyester PUR oligomer (PBA-PU) to produce a monomeric compound 4, 4'-methylene diphenylamine. Furthermore, strain YX8-1 was able to degrade 32% of the commercialized polyester PUR sponges within 30 days. This study thus provides a strain capable of biodegradation of PUR waste, which may facilitate the mining of related degrading enzymes.

Screening and identification of a polyurethane-degrading bacterium G-11 and its plastic degradation characteristics / 生物工程学报

Polyurethane (PUR) plastics is widely used because of its unique physical and chemical properties. However, unreasonable disposal of the vast amount of used PUR plastics has caused serious environmental pollution. The efficient degradation and utilization of used PUR plastics by means of microorganisms has become one of the current research hotspots, and efficient PUR degrading microbes are the key to the biological treatment of PUR plastics. In this study, an Impranil DLN-degrading bacteria G-11 was isolated from used PUR plastic samples collected from landfill, and its PUR-degrading characteristics were studied. Strain G-11 was identified as Amycolatopsis sp. through 16S rRNA gene sequence alignment. PUR degradation experiment showed that the weight loss rate of the commercial PUR plastics upon treatment of strain G-11 was 4.67%. Scanning electron microscope (SEM) showed that the surface structure of G-11-treated PUR plastics was destroyed with an eroded morphology. Contact angle and thermogravimetry analysis (TGA) showed that the hydrophilicity of PUR plastics increased along with decreased thermal stability upon treatment by strain G-11, which were consistent with the weight loss and morphological observation. These results indicated that strain G-11 isolated from landfill has potential application in biodegradation of waste PUR plastics.

Pectus excavatum ­ Correção cirúrgica utilizando tala externa de poliuretano fabricada com tecnologia de impressão 3D / Pectus excavatum ­ Surgical correction, using polyurethane external splint made with 3D printing technology

Objetivou-se relatar o emprego de uma tala externa confeccionada com material de poliuretano e cobertura interna de neopreme na reparação cirúrgica do pectus excavatum em um felino jovem. O felino apresentava deformidade anatômica congênita na região do externo e sinais clínicos respiratórios. Imagens avançadas de tomografia foram utilizadas para moldar a tala impressa com tecnologia tridimensional. Esta alternativa possibilitou melhor planejamento cirúrgico e, com isso, conforto para o paciente, além da qualidade própria do material de poliuretano que é levemente maleável, o que permitiu melhor moldagem e expansão torácica durante a respiração. A tala se provou resistente o suficiente para suportar a tração ocasionada pelos fios de sutura e possibilitou o reposicionamento adequado do osso esterno ao mesmo tempo que se mostrou confortável e acarretou mínimas lesões ao paciente.

The aim of this paper was to report the use of an external splint made of polyurethane material and internal neopreme covering in the surgical repair of a pectus excavatum in a young feline. The feline exhibited a congenital anatomical deformity in the external region and clinical respiratory signs. Advanced CT images were used to shape the 3D-printed splint. This alternative allowed better surgical planning and, therefore, comfort for the patient, this because to the quality of the polyurethane material, which is slightly malleable, and allowed for better molding and chest expansion during breathing. The splint proved to be strong enough to withstand the traction caused by the suture threads and allowed the proper repositioning of the sternum, at the same time it was comfortable and caused minimal injuries to the patient.

Selective Separation and Preconcentration of Caffeine from Natural and Pharmaceutical Products using New Polyurethane Foams

Abstract Two polyurethane foam-based sorbents (PUF) were synthesized by imprinting and grafting techniques and examined for selective separation and preconcentration of caffeine (CAF) in some pharmaceutical products and in black tea. Molecularly imprinted PUF was synthesized based on hydrogen-bonding interactions between CAF and alizarin yellow G (AYG) and subsequent polymerization into PUF. The static experiments indicated optimum sorption conditions at pH=6.5 and 5.5 for imprinted PUF (AY-IPUF) and grafted PUF (AY-GPUF), respectively. In the online experiments, the suitable preconcentration time was found to be 40 and 20s for (AY-IPUF) and (AY-GPUF), respectively, at a flow rate of 1.75 mL.min-1. Desorption of CAF has been affected by passing 500 µL of 0.05, 0.01 mol.L−1 HCl eluent onto (AY-IPUF) and (AY-GPUF), respectively. The online methods have provided satisfactory enrichment factors of 8.4 and 10.5 for (AY-IPUF) and (AY-GPUF), respectively. The time consumed for preconcentartion, elution and determination steps was 1.48 and 1.05 min, thus, the throughput was 42 and 57 h-1, for (AY-IPUF) and (AY-GPUF), respectively. The developed sorbents were studied for the determination of CAF in pharmaceutical samples which will be helpful to minimize caffeinism. Finally, in silico bioactivity, ADMET and drug-likeness predictive computational studies of caffeine were also carried out

Feasibility study on the preparation of novel negative pressure materials for constructing new matrix of full-thickness skin defect wounds in rats / 中华烧伤杂志

Objective: To explore the feasibility on the preparation of novel negative pressure materials for constructing new matrix of full-thickness skin defect wounds in rats. Methods: The experimental research method was applied. The microstructure of polyurethane foam dressing which was commonly used in negative pressure treatment was observed under scanning electron microscope, and its pore diameter was detected (n=5). Polycaprolactone (PCL) and polybutylene succinate (PBS) were used respectively as raw materials for the preparation of PCL and PBS negative pressure materials by melt spinning technology, with the measured pore diameter of polyurethane foam dressing as the spinning spacing at the spinning rates of 15, 25, and 35 mm/s, respectively. The microstructures of the prepared negative pressure materials were observed under scanning electron microscope, and their fiber diameters were measured. The tensile strength and tensile modulus of the prepared negative pressure materials and polyurethane foam dressing were measured by tensile testing machine and composite testing machine, respectively (n=5), to screen the spinning rate for subsequent preparation of negative pressure materials. Human skin fibroblasts (Fbs) in logarithmic growth phase were co-cultured with PCL negative pressure material and PBS negative pressure material prepared at the selected spinning rate, respectively. After 1, 4, and 7 day (s) of co-culture, the cell activity and adhesion in the materials was detected by living/dead cells detection kit, and the cell proliferation level in the materials was detected by cell counting kit 8 method (n=5). A full-thickness skin defect wound was prepared on the back of 18 5-6 weeks old Sprague-Dawley rats (gender unlimited). Immediately after injury, the injured rats were divided into PCL+polyurethane group, PBS+polyurethane group, and polyurethane alone group according to the random number table (with 6 rats in each group). The wounds were covered with materials containing corresponding component and performed with continuous negative pressure suction at the negative pressure of -16.7 kPa. The wound tissue along with materials directly contacted to the wound (hereinafter referred to as wound specimens) were collected from 3 rats in each group after 7 and 14 days of negative pressure treatment (NPT), respectively. The growth of granulation tissue and the attachment of material to wound surface were observed after hematoxylin-eosin staining, the collagen fiber deposition was observed after Masson staining, and CD34 and interleukin-6 (IL-6) positive cells were detected and counted by immunohistochemical staining. Data were statistically analyzed with one-way analysis of variance, analysis of variance for factorial design, least significant difference-t test, Kruskal-Wallis H test, Mann-Whitney U test, and Bonferroni correction. Results: The microstructure of polyurethane foam dressing was loose and porous, with the pore diameter of (815±182) μm. The spinning spacing for the subsequent negative pressure material was set as 800 μm. The microstructures of PBS negative pressure material and PCL negative pressure material were regular, with vertically interconnected layers and continuous fibers in even thickness, but the fibers of PBS negative pressure material were straighter than those of PCL negative pressure material. There was no obvious difference in the microstructure of negative pressure materials prepared from the same raw material at different spinning rates. The fiber diameters of PCL negative pressure materials prepared at three spinning rates were similar (P>0.05). The fiber diameters of PBS negative pressure materials prepared at spinning rates of 25 mm/s and 35 mm/s were significantly smaller than the fiber diameter of PBS negative pressure material prepared at the spinning rate of 15 mm/s (with t values of 4.99 and 6.40, respectively, P<0.01). Both the tensile strength and tensile modulus of PCL negative pressure materials prepared at three spinning rates were similar (P>0.05). The tensile strength of PBS negative pressure materials prepared at spinning rates of 15 mm/s and 25 mm/s was significantly lower than that of PBS negative pressure materials prepared at the spinning rate of 35 mm/s (with t values of 9.20 and 8.92, respectively, P<0.01), and the tensile modulus was significantly lower than that of PBS negative pressure materials prepared at the spinning rate of 35 mm/s (with t values of 2.58 and 2.47, respectively, P<0.05). Subsequently, PCL negative pressure material was prepared at the spinning rate of 35 mm/s, and PBS negative pressure material was prepared at the spinning rate of 15 mm/s. After 1, 4, and 7 day (s) of co-culture, the number of human skin Fbs that adhered to PCL negative pressure material and PBS negative pressure material increased with time, and there was no significant difference between the two materials. After 1 and 7 day (s) of co-culture, the proliferation levels of human skin Fbs between the two negative pressure materials were similar (P>0.05). After being co-cultured for 4 days, the proliferation level of human skin Fbs in PBS negative pressure material was significantly higher than that in PCL negative pressure material (t=6.37, P<0.01). After 7 days of NPT, the materials were clearly identifiable and a small amount of collagen fibers were also observed in the wound specimens of rats in the three groups; a small amount of granulation tissue was observed in the wound specimens of rats in polyurethane alone group. After 14 days of NPT, a large number of granulation tissue and collagen fibers were observed in the wound specimens of rats in the three groups; the materials and wound tissue in the wound specimens of rats in PCL+polyurethane group could not be clearly distinguished. After 7 and 14 days of NPT, the collagen fibers in the wound specimens of rats in polyurethane alone group were denser than those in the other two groups. After 7 days of NPT, the number of CD34 positive cells in the wound specimens of rats in PBS+polyurethane group was 14.8±3.6 per 400 times visual field, which was significantly less than 27.8±9.1 in polyurethane alone group (t=3.06, P<0.05); the number of IL-6 positive cells was 60 (49, 72), which was significantly more than 44 (38, 50) in polyurethane alone group (Z=2.41, P<0.05). After 14 days of NPT, the number of IL-6 positive cells in the wound specimens of rats in PBS+polyurethane group was 19 (12, 28) per 400 times visual field, which was significantly more than 3 (1, 10) in PCL+polyurethane group and 9 (2, 13) in polyurethane alone group (with Z values of 2.61 and 2.40, respectively, P<0.05). Conclusions: The prepared PCL negative pressure material and PBS negative pressure material have good biocompatibility, and can successfully construct the new matrix of full-thickness skin defect wounds in rats. PCL negative pressure material is better than PBS negative pressure material in general.

Characterization of Humicola insolens cutinase-tachystatin A2 fusion protein and its application in treatment of recycled paper stickies / 生物工程学报

With the decrease of forest timber resources, the recycling of waste paper has received increasing attention. However, the stickies produced in the process of waste paper recycling may negatively affect the production of recycled paper. The biological decomposition of stickies, which has the advantages of high efficiency, high specificity and pollution-free, is achieved mainly through the enzymatic cleavage of the ester bond in the stickies components to prevent flocculation. Cutinase is a serine esterase that can degrade some components of the stickies. Previous research indicated that the anchor peptide tachystatin A2 (TA2) is able to bind polyurethane. In this study, the cutinase HiC derived from Humicola insolens was used to construct a fusion protein HiC-TA2 by megaprimer PCR of the whole plasmid (MEGAWHOP). The enzymatic properties and the degradation efficiency of the fusion protein on poly(ethyl acrylate) (PEA), a model substrate of stickies component, were determined. The results showed that the degradation efficiency, the size decrease of PEA particle, and the amount of ethanol produced by HiC-TA2 were 1.5 times, 6.8 times, and 1.4 times of that by HiC, respectively. These results demonstrated that TA2 improved the degradation efficiency of HiC on PEA. This study provides a useful reference for biological decomposition of stickies produced in the process of recycled paper production.

Linfoma anaplásico de células grandes asociado a implante mamario. Reporte de un caso y revisión de la literatura. / Breast Implant Associated-Anaplastic Large Cell Lymphoma (BIA-ALCL) - Argentinian case

El linfoma anaplásico de células grandes asociado a implantes mamarios LACG-AI o BIA-ALCL, abreviatura en inglés de "Breast Implant Associated-Anaplastic Large Cell Lymphoma", es una nueva entidad reconocida por la OMS desde el 2016, de rara incidencia y que aún plantea muchos interrogantes. Desde su primera mención en 1997 (J. Keech - B. Creech) su incidencia ha ido en aumento. En julio de 2020, 953 casos en el mundo según el Registro de la Sociedad Americana de Cirujanos Plásticos (PROFILE), y las publicaciones se multiplican exponensialmente año a año demostrando el interés que suscita. Se ha descripto una fuerte asociación con las superficies texturizadas de los implantes mamarios y con el tipo de material (mayor textura "grado 4" y cubierta de poliuretano mayor riesgo) llegando a describirse tasas tan altas omo 1/2830 en Australia/Nueva Zelanda. Su presentación clínica en casi el 75% es bajo la forma de un seroma tardío y el tiempo de exposición promedio ronda entre los 7 a 11 años. El diagnóstico histo-patológico integra el examen morfológico con la caracterización molecular, visualizándose grandes célular anaplásicas CD30 (+), ALK (-). El tratamiento quirúrgico, capsulectomía bilateral en estadios tempranos es el gold standard. Su pronóstico es excelente con exérsis completas. Objetivo: actualizar la información sobre esta novel enfermedad y comentar un caso propio que presenta todas las características descriptas en la literatura, siendo el 14° registrado en Argentina

The anaplastic large cell lymphoma associated with breast implants, LACCG-AI o BIA-ALCL abbreviation in English, is an entity recognized by the WHO since 2016 of rare incidence and that still raises many questions. Since its firts mention in 1997 (J. Keech - B. Creech) its incidence has been increasing, In july 2020, 953 cases in the world according to the Registry of the America Society of Plastic Surgeons (PROFILE), and the publications multiply exponentially year after year, demonstrating the interest it arouses, A strong association has been described with the textured surfaces of breast implants and with the type of material (greater texture "grade 4" and higher risk polyurethane cover), reaching rates as high as 1/2830 in Australia / New Zealand. Its clinical presentation in almost 75% is in the form of a late seroma and the average exposure time is between 7 to 11 years. The pathological anatomical diagnosis integrates the morphological examination with the molecular characterization, visualizing large anaplastic CD30 (+), ALK (-) cells. Surgical treatment, bilateral capsulectomy in early stages, is the gold standard. Her prognosis is excellent with complete exeresis. Objetive: to update the information on this novel disease and comment on an own case that presents all the characteristics described in the literature, the 14th being registered in Argentina

Craft Brewery Wastewater Treatment: a Fixed-Bed Single-Batch Reactor with Intermittent Aeration to Remove COD and TN

Abstract This study evaluated an intermittently aerated, fixed-bed, single-batch reactor, with mini BioBob© as biofilm media support, as an alternative treatment of craft brewery wastewater. In order to remove chemical oxygen demand (COD) and total nitrogen (TN), seven conditions were performed in a central composite experimental design (CCD) with different aeration times (1, 2 and 3 h in a 4 h cycle) and hydraulic retention times (HRT) (12, 16 and 20 h). The results showed that the removal of COD and TN were positively affected by increased aeration time and HRT. The condition that presented the best quality effluent was Condition No. 1 (20 h HRT and 3 h aeration), with 209 ± 28 mg COD L-1; 3.00 ± 0.15 mg TKN L-1 ; and 0.67 ± 0.11 mg NO3-N L-1. Kinetic assays showed that the highest values for the substrate removal rate constant, kCOD = 0.1774 h-1 were obtained with the longest aeration time (3 h). The most probable number (MPN) test showed a higher concentration of denitrifying bacteria (heterotrophic), 3.3 x 106, than for AOB and NOB bacteria (autotrophic), which were 4.9 x 103 and 2.7 x 103, respectively. Moreover, it was possible to verify that correcting the influent alkalinity with 7.14 mg CaCO3 for each 1 mg of TKN resulted in better process efficiency. It was concluded that COD and TN can be removed from craft brewery wastewater using an intermittently aerated, fixed-bed, single-batch reactor with mini Biobob© as biofilm media support.

A castor oil plant (Ricinus communis)-derived implant improves the biomechanical properties of noncritical bone defects

ABSTRACT Purpose The biomechanical properties of the polyurethanes implant material derived from castor oil plant (Ricinus communis) were evaluated in a noncritical bone defect model in rat tibia. Methods After three weeks of the implant application, the tibias were tested by means of the biomechanical three-point flexion test and resistance, rigidity, energy at maximum load and maximum energy were evaluated. Nonparametric statistical analysis was performed. Results It was found that the group that received the implant behaved the same as the intact control group and also showed a significant increase in maximum load compared to the spontaneous repair group. Conclusions Our results indicate that the tibias with the implant material in a noncritical bone defect recover normal biomechanical parameters in less time than spontaneously.

Advances in microbial degradation of plastics / 生物工程学报

Plastics are widely used in daily life. Due to poor management and disposal, about 80% of plastic wastes were buried in landfills and eventually became land and ocean waste, causing serious environmental pollution. Recycling plastics is a desirable approach, but not applicable for most of the plastic waste. Microbial degradation offers an environmentally friendly way to degrade the plastic wastes, and this review summarizes the potential microbes, enzymes, and the underpinning mechanisms for degrading six most commonly used plastics including polyethylene terephthalate, polyethylene, polyvinyl chloride, polypropylene, polystyrene and polyurethane. The challenges and future perspectives on microbial degradation of plastics were proposed.

Isolation and characterization of a polyurethane-degrading bacterium / 生物工程学报

Biodegradation of polyurethane (PUR) pollutants by microorganisms has received widespread attention currently. Identification of microorganisms capable of efficiently degrading PUR plastics is a key point. In this study, a strain P10 capable of degrading PUR was isolated from the plastic wastes, and identified as a bacterium belonging to the genus of Brevibacillus based on colony morphology and 16S rDNA phylogenetic analysis. Brevibacillus sp. P10 was capable of degrading 71.4% of waterborne polyurethane (Impranil DLN) after 6 days growth in MSM medium with DLN as a sole carbon source. In addition, strain P10 can use commercial PUR foam as the sole carbon source for growth. Brevibacillus sp. P10 can degrade 50 mg PUR foam after 6 days growth in MSM medium supplemented with 5% (V/V) LB after optimization of degradation conditions. This indicates that Brevibacillus sp. P10 has potential to be used in biodegradation of PUR waste.

Degradation of petroleum-based plastics by microbes and microbial consortia / 生物工程学报

Along with the increasingly serious environmental pollution, dealing with the "white pollution" issue, which is caused by the worldwide use of not readily-degradable or non-degradable synthetic plastics, has become a great challenge. It is an environmentally friendly strategy to degrade synthetic plastics using microorganisms that exist in nature or evolved under selection pressure. Based on the NSFC-EU International Cooperation and Exchanges Project "Bio Innovation of a Circular Economy for Plastics", this review summarized the screening of bacteria, fungi and microbial consortia capable of degrading synthetic plastics such as polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyurethane (PUR), and polyethylene terephthalate (PET). We also analyzed the role of various microorganisms played in the degradation of petroleum-based plastics. Moreover, we discussed the pros and cons of using microorganisms and enzymes for degradation of synthetic plastics.

Avaliação da deformação do preparo de superfície de implantes dentários submetidos a diferentes intensidades de torque / Deformation analysis of the surface preparation in dental implants submitted to different torque intensities

Introdução: o aprimoramento do processo de osseointegração faz com que os investimentos em pesquisa e o desenvolvimento de novos materiais e tratamentos de superfície sejam despendidos para promover a relação entre osso e implante. Uma das condições para o sucesso é a ausência de micromovimentos ou estabilidade primária da peça implantada, fato esse que leva alguns cirurgiões a aplicar torques excessivos sobre o implante, podendo resultar em danos ao tratamento aplicado à superfície externa do mesmo. Objetivo: o presente trabalho investigou possíveis níveis de deformação do preparo de superfície conforme diferentes valores de torque foram aplicados à dois sistemas de implantes para avaliar os possíveis danos causados. Metodologia: foram instalados 5 implantes do sistema Dérig e 5 implantes do sistema Straumann em um bloco de poliuretano, para posterior remoção com contra-torque e avaliação da superfície sob o Microscópio Eletrônico de Varredura (MEV). Resultados: nos resultados obtidos, no grupo de implantes Dérig não foi possível constatar evidências que comprovem que a elevação dos valores de torque aplicados aos implantes até 95 Ncm danifiquem ou alterem a estrutura do preparo de superfície externa dos implantes, contudo, no grupo Straumann, verificamos danos e alterações no preparo de superfície com torque progressivo a partir de 50 Ncm. Conclusão: possíveis alterações e danos ao preparo de superfície de implantes que apresentem rugosidade de superfície aumentada por jateamento podem ocorrer em torques acima de 50 Ncm empregados com o objetivo de aumentar sua estabilidade primária.

Introduction: improving the osseointegration process means that investments in research and development of new materials and surface treatments are expended to promote the relationship between bone and implant. One of the conditions for success is the absence of micromovements or primary stability of the implanted part. This fact causes some surgeons to apply excessive torque to the implant, which may result in damage to the treatment applied to the external surface of the implant. Objective: The present work investigated possible surface preparation deformation levels as different torque values were applied to two implant systems to evaluate the possible damage caused. Methodology: ive Dérig system implants and five Straumann system implants were installed in a polyurethane block for subsequent counter-torque removal and surface evaluation under the Scanning Electron Microscope (SEM). Results: Iin the obtained results, in the Dérig implant group it was not possible to verify evidences that the increase of the torque values applied to the implants up to 95 Ncm could damage or alter the structure of the external surface preparation of the implants, however, in the Straumann group we verified damage and changes in surface preparation with progressive torque from 50 Ncm. Conclusion: possible alterations and damages to the surface preparation of implants that present increased surface roughness by blasting can occur in torques above 50 Ncm employed in order to increase their primary stability.

The Role of Pedicle Screw Surface on Insertion Torque and Pullout Strength / Influência da superfície dos parafusos pediculares no torque de inserção e resistência ao arrancamento

Abstract Objective Compare by mechanical tests the pullout resistance and the insertion torque of rough and smooth pedicle screws. Methods Pedicle screws with rough surface and smooth surface, with diameters of 4.8; 5.5 and 6.5 mm, were inserted in polyurethane blocks with density of 10 PCF (0.16 g/cm3). Insertion torque and pullout strength were assessed. Results The pullout strength of the rough surface and smooth surface screws did not differ, except in the group of 4.8 mm diameter screws. In this group, the rough surface screws showed greater resistance to pullout. Conclusion Pedicle screws with a rough surface did not show increased pullout resistance in the acute phase of their insertion in polyurethane blocks compared to smooth surface screws. The rough surface screws had a higher insertion torque than the smooth surface screws, depending on the diameter of the screw and the preparation of the pilot hole.

Resumo Objetivo Comparar por testes mecânicos a resistência ao arrancamento e o torque de inserção do parafuso pedicularjateado e liso. Métodos Parafusos pediculares de superfície áspera e de superfície lisa com diâmetros de 4,8; 5,5 e 6,5 mm foram inseridos em blocos de poliuretano com densidade de 10 PCF (0,16 g/cm3). O torque de inserção e a força de arrancamento foram avaliados. Resultados A força de arrancamento dos parafusos de superfície áspera e de superfície lisa não diferiu, exceto no grupo de parafusos com 4,8 mm de diâmetro. Nesse grupo, os parafusos de superfície áspera apresentaram maior resistência ao arrancamento. Conclusão Os parafusos pediculares de superfície áspera não apresentaram aumento da resistência ao arrancamento na fase aguda de sua inserção em blocos de poliuretano em relação aos parafusos de superfície lisa. Os parafusos de superfície áspera apresentaram maior torque de inserção que os parafusos de superfície lisa, dependendo do diâmetro do parafuso e da preparação do furo piloto.

Influence of an alternative implant design and surgical protocol on primary stability

Abstract The purpose of thisin vitrostudy was to evaluate the influence of a new proposal of implant design and surgical protocol on primary stability in different bone densities. Four groups were tested (n=9): G1 - tapered, cone morse, Ø 4.3 mm x 10 mm in length (Alvim CM); G2 - experimental tapered; G3 - cylindrical, cone morse, Ø 4.0 mm x 11 mm in length (Titamax CM) and G4 - experimental cylindrical. The experimental implants were obtained from a design change in the respective commercial models. The insertion was performed in polyurethane (PU) blocks 0.24 g/cm3(20 pcf) and 0.64 g/cm3(40 pcf), according to different surgical protocols. The primary stability was measured by means of insertion torque (IT) and pullout test. Data were analyzed by ANOVA, Tukey's test (α=0.05) and Pearson's correlation. For IT and pullout, conventional and experimental implants showed no difference between them when inserted in the 20 pcf PU (p>0.05). In the 40 pcf PU, the modified implants exhibited greater IT (p<0.05) and lower pullout (p<0.05) compared to the respective conventional models. The implant design tested associated with the surgical protocol, positively influenced primary stability in higher density bones.

Resumo O objetivo deste estudo in vitro foi avaliar a influência de uma nova proposta de design de implante e protocolo cirúrgico na estabilidade primária em diferentes densidades ósseas. Foram testados quatro grupos (n=9): G1 - cônico, cone morse, Ø 4,3 mm x 10 mm de comprimento (Alvim CM); G2 - experimental cônico; G3 - cilíndrico, cone morse, Ø 4,0 mm x 11 mm de comprimento (Titamax CM) e G4 - experimental cilíndrico. Os implantes experimentais foram obtidos a partir de uma mudança no design dos respectivos modelos comerciais. A inserção foi realizada em blocos de poliuretano (PU) 0,24 g/cm3 (20 pcf) e 0,64 g/cm3 (40 pcf), de acordo com diferentes protocolos cirúrgicos. A estabilidade primária foi aferida por meio do torque de inserção (TI) e ensaio de arrancamento. Os dados foram analisados por ANOVA, teste de Tukey (α=0,05) e correlação de Pearson. Para TI e arrancamento, os implantes convencionais e experimentais não mostraram diferença entre si quando inseridos na PU de 20 pcf (p>0,05). Na PU de 40 pcf, os implantes modificados exibiram maior TI (p <0,05) e menor arrancamento (p <0,05) em relação aos respectivos modelos convencionais. O design do implante testado associado ao protocolo cirúrgico, influenciou positivamente a estabilidade primária em ossos de maior densidade.

Composite-derived monomers affect cell viability and cytokine expression in human leukocytes stimulated with Porphyromonas gingivalis

Abstract Objectives: Dental composites release unreacted resin monomers into the oral environment, even after polymerization. Periodontal cells are, therefore, exposed to substances that potentially elicit the immune inflammatory response. The underlying molecular mechanisms associated with the interaction between resin monomers and human immune cells found in the gingival crevicular fluid are not fully understood yet. This study investigated the ability of bisphenol A-glycidyl methacrylate (BISGMA), urethane dimethacrylate (UDMA) and triethylene glycol dimethacrylate (TEGDMA) to induce apoptosis and cytokine release by human leukocytes stimulated with a periodontal pathogen. Methodology: Peripheral blood mononuclear cells (PBMC) from 16 healthy individuals were included in this study. To determine the toxicity, the PBMC were incubated for 20 hours, with monomers, for the analysis of cell viability using MTT assay. To evaluate cell death in the populations of monocytes and lymphocytes, they were exposed to sub-lethal doses of each monomer and of heat-inactivated Porphyromonas gingivalis (P. gingivalis) for 5 hours. Secretions of IL-1β, IL-6, IL-10 and TNF-α were determined by ELISA after 20 hours. Results: UDMA and TEGDMA induced apoptosis after a short-time exposure. Bacterial challenge induced significant production of IL-1β and TNF-α (p<0.05). TEGDMA reduced the bacterial-induced release of IL-1β and TNF-α, whereas UDMA reduced IL-1β release (p<0.05). These monomers did not affect IL-10 and IL-6 secretion. BISGMA did not significantly interfere in cytokine release. Conclusions: These results show that resin monomers are toxic to PBMC in a dose-dependent manner, and may influence the local immune inflammatory response and tissue damage mechanisms via regulation of bacterial-induced IL-1β and TNF-α secretion by PBMC.

Development of a Novel Spawn (Block Spawn) of an Edible Mushroom, Pleurotus ostreatus, in Liquid Culture and its Cultivation Evaluation

Mushroom cultivation has gained increased attention in recent years. Currently, only four types of spawn, including sawdust spawn, grain spawn, liquid spawn, and stick spawn, are commonly available for mushroom cultivation. This limited spawn diversity has led to difficulty in selecting suitable inoculum materials in some cultivation. In this study, three small blocks of lignocellulosic agro-wastes and one block of a synthetic matrix were prepared as support for growing Pleurotus ostreatus in liquid medium. Mycelium-adsorbed blocks were then evaluated for their potential as block spawn for fructification. Our results indicated that the edible fungus was adsorbed and abundantly grew internally and externally on loofah sponge and synthetic polyurethane foam (PUF) supports and also has the ability to attach and grow on the surface of sugarcane bagasse and corncob supports. The mycelia of P. ostreatus adhered on corncob exhibited the highest metabolic activity, while those on the PUF showed the least activity. Mycelial extension rates of block spawns made of agro-waste materials were comparable to that of sawdust spawn, but the block spawn of PUF showed a significantly lower rate. No significant differences in cropping time and yield were observed among cultivations between experimental block spawns and sawdust spawns. Moreover, the corncob block spawn maintained its fruiting potential during an examined period of 6-month storage. The developed block spawn could be practically applied in mushroom cultivation.

Inhalation risk assessment of naphthalene emitted from deodorant balls in public toilets

The inhalation of naphthalene used as deodorant balls in public toilets could be an important cancer risk factor. The atmospheric concentration of naphthalene in public toilets (C(in)) was estimated both by a polyurethane foam passive air sampler (PUF-PAS) deployed in nine public toilets in Seoul, Korea and by a steady-state indoor air quality model, including emission estimation using Monte-Carlo simulation. Based on the estimated C(in), cancer risk was also assessed for cleaning workers and the general population. The steady-state C(in) estimated using the estimated emission rate, which assumed that air exchange was the only process by which naphthalene was removed, was much greater than the C(in) value measured using PUF-PAS in nine public toilets, implying the importance of other removal processes, such as sorption to walls and the garments of visitors, as well as decreased emission rate owing to wetting of the naphthalene ball surface. The 95 percentile values of cancer risk for workers based on the estimation by PUF-PAS was 1.6×10⁻⁶, whereas those for the general public were lower than 1×10⁻⁶. The results suggested that naphthalene deodorant balls in public toilets may be an important cancer risk factor especially for the cleaning workers.

Inhalation risk assessment of naphthalene emitted from deodorant balls in public toilets

The inhalation of naphthalene used as deodorant balls in public toilets could be an important cancer risk factor. The atmospheric concentration of naphthalene in public toilets (C(in)) was estimated both by a polyurethane foam passive air sampler (PUF-PAS) deployed in nine public toilets in Seoul, Korea and by a steady-state indoor air quality model, including emission estimation using Monte-Carlo simulation. Based on the estimated C(in), cancer risk was also assessed for cleaning workers and the general population. The steady-state C(in) estimated using the estimated emission rate, which assumed that air exchange was the only process by which naphthalene was removed, was much greater than the C(in) value measured using PUF-PAS in nine public toilets, implying the importance of other removal processes, such as sorption to walls and the garments of visitors, as well as decreased emission rate owing to wetting of the naphthalene ball surface. The 95 percentile values of cancer risk for workers based on the estimation by PUF-PAS was 1.6×10⁻⁶, whereas those for the general public were lower than 1×10⁻⁶. The results suggested that naphthalene deodorant balls in public toilets may be an important cancer risk factor especially for the cleaning workers.

An innovative method in venous coronary cast technique / 대한해부학회지

Polyurethane foam (PU foam) is a new material which is being used in producing both macro-anatomical and micro-anatomical specimens. PU foam is simple to use, without need for special equipment. The present study was carried out to evaluate morphology of coronary sinus and its tributaries. During the study, we encountered few problems in carrying out injections. Coronary sinus and its tributaries were difficult to cannulate since the coronary sinus lacks a vascular stem, around which ligature can be tied before injection so that the cannula can be held in place. In contrast, in majority of the organs it is easy to inject since they possess tubular vascular stem to hold the cannula in place. A new device was developed which could be used to cannulate coronary sinus orifice to inject the casting media. The second problem we faced was saponification of adipose tissue. This made corrosion of the soft tissue difficult. Hence in this study, we describe the device we have developed to place in the coronary sinus orifice, and how saponified adipose tissue was taken care during the actual maceration step.