Biological control of foodborne pathogens by lacticacid bacteria: A focus on juice processing industries

Abstract The use of lactic acid bacteria (LAB) in foods as biocontrol agents against foodborne pathogens has become increasingly known. Under the premise that controlling the adhesion of microorganisms to food contact surfaces is an essential step for meeting the goals of food processing, the aim of this work was to investigate the inhibitory and anti-biofilm effectiveness of Lactobacillus rhamnosus GG (ATCC 53103) and Lactobacillus casei (ATCC 393) against Escherichia coli O157:H7, Salmonella enterica and Listeria monocytogenes. Lactobacillus strains (108UFCCFU/ml) and pathogens (104UFCCFU/ml) were evaluated to monitor LAB anti-adhesive and antibiofilm effect, in two main scenarios: (i) co-adhesion and (ii) pathogen incorporation to stainless steel surfaces with a protective biofilm of Lactobacillus cells. In (i) the predominant effect was observed in L. rhamnosus against S. enterica and L. monocytogenes, whereas in (ii) both LAB significantly reduced the number of pathogenic adherent cells. The effect of pre-established LAB biofilms was more successful in displacing the three pathogens than when they were evaluated under co-adhesion. These findings show that both LAB can be considered good candidates to prevent or inhibit the adhesion and colonization of L. monocytogenes, S. enterica and E. coli O157:H7 on surfaces and conditions of relevance for juice processing industries, offering alternatives for improving the safety and quality of fruit-based products.

Resumen Existe un creciente interés en el uso de bacterias ácido lácticas (BAL) como agentes de biocontrol frente a patógenos de transmisión alimentaria. Bajo la premisa de que el control de la adhesión de microorganismos a superficies de contacto con alimentos es el paso esencial para evitar su contaminación, el objetivo de este trabajo fue investigar la efectividad inhibitoria y antibiofilm de Lactobacillus rhamnosus GG (ATCC 53103) y Lactobacillus casei (ATCC 393) frente a Escherichia coli O157:H7, Salmonella enterica y Listeria monocytogenes. A fin de cumplir con el objetivo propuesto, las cepas de Lactobacillus (108UFCUFC/ml) y los patógenos (104UFCUFC/ml) se ensayaron en 2 escenarios: (1) coadhesión, y (2) incorporación de los patógenos a las superficies de acero inoxidable con un biofilm preformado de Lactobacillus. En (1), el efecto predominante se observó con L. rhamnosus frente a S. enterica y L. monocytogenes, mientras que en (2), ambas BAL redujeron significativamente el número de células patógenas adheridas. En función de estos resultados, concluimos que el efecto de un biofilm preformado de ambas BAL fue más exitoso en el desplazamiento de los 3 patógenos que en coadhesión. Ambas BAL pueden considerarse buenas candidatas para mitigar la adhesión y colonización de L. monocytogenes, S. enterica y E. coli O157:H7 en superficies en condiciones de relevancia para la industria procesadora de jugos, y, de esta manera, ofrecer alternativas para mejorar la seguridad y calidad de los alimentos a base de frutas.

EFFECT ON FINANCIAL PERFORMANCE ANALYSIS WITH SPECIAL REFERENCE TO SALEM STEEL PLANT AT SALEM

The present study aims to identify the ?nancial strengths and weaknesses of the salem steel plant by properly establishing relationships between the items of the balance sheet and pro?t and loss account. The study covers Salem Steel Plant, a special steels unit of Steel Authority of India Ltd, pioneered the supply of wider width stainless steel sheets / coils in India. The study has been undertaken for the period of twelve years from 2011-12 to 2020-21and the necessary data have been obtained from SAIL database. The liquidity position was strong in case of both the selected companies thereby re?ecting the ability of the companies to pay short-term obligations on due dates and they relied more on external funds in terms of long-term borrowings thereby providing a lower degree of protection to the creditors. The study will help investors to identify the nature of SAIL industry and will also help to take decision regarding investment.

Treatment with a proximal femoral locking plate versus a proximal femoral anti-rotation intramedullary nail for femoral intertrochanteric fractures in older adult patients / 中国基层医药

Objective:To investigate the efficacy of a proximal femoral locking plate (LPFP) versus a proximal femoral anti-rotation intramedullary nail (PFNA) in the treatment of femoral intertrochanteric fractures in older adult patients. Methods:A total of 130 older adult patients with femoral intertrochanteric fractures who received treatment in Linghu People's Hospital of Huzhou from May 2017 to June 2020 were included in this study. They were randomly assigned to undergo treatment with either a PFNA (observation group, n = 65) or an LPFP (control group, n = 65). Intraoperative blood loss, incision length, operative time, and time to fracture healing were determined in each group. At 1, 3, and 6 months after surgery, the Harris hip score was used to evaluate hip joint recovery. Coxa vara, incision infection, and internal fixation loosening were compared between the two groups. Results:Intraoperative blood loss in the observation group was less than that in the control group [(189.26 ± 48.15) mL vs. (96.47 ± 40.21) mL, t = -11.93, P < 0.001]. Incision length, operative time, and time to fracture healing in the observation group were significantly shorter than those in the control group [(4.03 ± 1.48) cm vs. (12.16 ± 1.55) cm, (72.13 ± 28.75) minutes vs. (120.34 ± 29.01) minutes, (9.89 ± 1.52) weeks vs. (13.63 ± 1.74) weeks, t = -30.59, -9.52, -13.05, all P < 0.001]. At 1 month after surgery, there was no significant difference in Harris hip score between the two groups ( t = 1.28, P > 0.05). At 3 and 6 months after surgery, the Harris hip score gradually increased in the control and observation groups ( F = 13.44, 8.26, both P < 0.001). At 3 and 6 months after surgery, Harris hip scores in the observation group were significantly higher than those in the control group [(85.17 ± 4.29) points vs. (79.50 ± 4.12) points, (95.30 ± 1.04) points vs. (87.69 ± 1.25) points, t = 7.69, 37.73, both P < 0.001]. The incidence of complications in the observation group was significantly lower than that in the control group [1.54% (1/65) vs. 10.77% (7/65), χ2 = 4.80, P = 0.029). Conclusion:Compared with LPFP, PFNA can effectively reduce intraoperative blood loss in older adult patients with femoral intertrochanteric fractures, accelerate the progress of fracture healing, promote the recovery of the hip joint, and has fewer complications. Therefore, PFNA is worthy of popularization.

Influencing factors of sleep disorders of employees of a steel enterprise / 环境与职业医学

Background Steel workers are exposed to occupational hazardous factors such as dust, noise, and heat, and often work in shifts, making them prone to sleep disorders. Objective To explore potential influencing factors of sleep disorders among workers in a steel enterprise in Gansu Province, and provide a basis for reducing the risk of sleep disorders among them. Methods From January to March 2022, a self-made questionnaire combined with the Pittsburgh Sleep Quality Index (PSQI) were used to investigate the employees of a steel enterprise in Gansu Province. According to their PSQI scores, they were divided into a normal sleep group and a sleep disorder group. The general demographic variables of the two groups were balanced by 1∶1 propensity score matching (PSM). Multiple logistic regression was used to analyze the contributing factors of sleep disorders. Restricted cubic spline (RCS) model was used to analyze potential dose-response relationship between weekly working hours and sleep disorders. Results The prevalence of sleep disorders in the steel workers was 48.06% (6029/12544). After PSM, 5847 pairs were successfully matched, and the distributions of matched variables were well balanced between the two groups. The results of multiple logistic regression showed that hypertension (OR=1.39, 95%CI: 1.24, 1.56), diabetes mellitus (OR=1.34, 95%CI: 1.07, 1.66), three-shift system (OR=1.26, 95%CI: 1.12, 1.41), dust exposure (OR=1.14, 95%CI: 1.01, 1.29), noise exposure (OR=1.23, 95%CI: 1.09, 1.39), heat exposure (OR=1.16, 95%CI: 1.04, 1.29), and work injury (OR=1.22, 95%CI: 1.02, 1.46) increased the risk of sleep disorders. Compared with workers with < 10 years of service, those with 10-20 years (OR=1.31, 95%CI: 1.19, 1.44), 20-30 years (OR=1.34, 95%CI: 1.19, 1.52), and ≥30 years of service (OR=1.35, 95%CI: 1.19, 1.53) had a higher risk of sleep disorders. Compared with non-exercise workers, the risk of developing sleep disorders was lower in workers with occasional exercise (OR=0.61, 95%CI: 0.56, 0.66) and regular exercise (OR=0.55, 95%CI: 0.49, 0.62). The RCS model showed that the weekly working hours and sleep disorders in the steel workers showed a nonlinear dose-response relationship (P<0.05 for overall trend, P<0.05 for nonlinear test). The relationship between weekly working hours and sleep disorders showed a "U" shaped distribution, with a significant increase in the risk of sleep disorders when the weekly working hours exceeded 49 h. Conclusion The non-occupational influencing factors of sleep disorders of employees in the steel enterprise include hypertension, diabetes, physical exercise, and occupational influencing factors include length of service, weekly working hours, shifts, dust exposure, noise exposure, heat exposure, and work injuries. It is recommended to consider both occupational and non-occupational factors to formulate appropriate sleep disorder prevention and control measures for steel employees to reduce the risk of sleep disorders.

A method for sensitivity analysis of deviation factor for geometric correction of cone-beam CT system / 南方医科大学学报

OBJECTIVE@#To propose a sensitivity test method for geometric correction position deviation of cone-beam CT systems.@*METHODS@#We proposed the definition of center deviation and its derivation. We analyzed the influence of the variation of the three-dimensional spatial center of the steel ball point, the projection center and the size of the steel ball point on the deviation of geometric parameters and the reconstructed image results by calculating the geometric correction parameters based on the Noo analytical method using the FDK reconstruction algorithm for image reconstruction.@*RESULTS@#The radius of the steel ball point was within 3 mm. The deviation of the center of the calibration parameter was within the order of magnitude and negligible. A 10% Gaussian perturbation of a single pixel in the 3D spatial coordinates of the steel ball point produced a deviation of about 3 pixel sizes, while the same Gaussian perturbation of the 2D projection coordinates of the steel ball point produced a deviation of about 2 pixel sizes.@*CONCLUSION@#The geometric correction is more sensitive to the deviation generated by the three-dimensional spatial coordinates of the steel ball point with limited sensitivity to the deviation generated by the two-dimensional projection coordinates of the steel ball point. The deviation sensitivity of a small diameter steel ball point can be ignored.

Efficacy of micro steel plate and Kirschner needle oblique and transverse internal fixation of adjacent metacarpal bone in the treatment of metacarpal diaphyseal oblique fracture / 中国骨伤

OBJECTIVE@#To compare the clinical efficacy of micro steel plate and Kirschner needle oblique and transverse internal fixation of adjacent metacarpal bone in the treatment of metacarpal diaphyseal oblique fracture.@*METHODS@#Fifty-nine patients with metacarpal diaphyseal oblique fractures admitted between January 2018 and September 2021 were selected as the study subjects and divided into the observation group (29 cases) and the control group (30 cases) based on different internal fixation methods. The observation group was treated with Kirschner wire oblique and transverse internal fixation of adjacent metacarpal bones, while the control group was treated with micro steel plate internal fixation. Postoperative complications, operation time, incision length, fracture healing time, treatment cost, and metacarpophalangeal function were compared between the two groups.@*RESULTS@#No incision or Kirschner wire infections occurred in the 59 patients, except for one in the observation group. No fixation loosening, rupture, or loss of fracture reduction occurred in any of the patients. The operation time and incision length in the observation group were (20.5±4.2) min and (1.6±0.2) cm, respectively, which were significantly shorter than those in the control group (30.8±5.6) min and (4.3±0.8) cm (P<0.05). The treatment cost and fracture healing time in the observation group were (3 804.5±300.8) yuan and (7.2±1.1) weeks, respectively, which were significantly lower than those in the control group (9 906.9±860.6) yuan and (9.3±1.7) weeks (P<0.05). The excellent and good rate of metacarpophalangeal joint function in the observation group was significantly higher than that in the control group at 1, 2, and 3 months after operation (P<0.05), but there was no significant difference between the two groups at 6 months after operation (P>0.05).@*CONCLUSION@#Micro steel plate internal fixation and Kirschner wire oblique and transverse internal fixation of adjacent metacarpal bones are both viable surgical methods for treating metacarpal diaphyseal oblique fractures. However, the latter has the advantages of causing less surgical trauma, shorter operation time, better fracture healing, lower cost of fixation materials, and no need for secondary incision and removal of internal fixation.

Three-dimensional printed 316L stainless steel cardiovascular stent's electrolytic polishing and its mechanical properties / 生物医学工程学杂志

The interventional therapy of vascular stent implantation is a popular treatment method for cardiovascular stenosis and blockage. However, traditional stent manufacturing methods such as laser cutting are complex and cannot easily manufacture complex structures such as bifurcated stents, while three-dimensional (3D) printing technology provides a new method for manufacturing stents with complex structure and personalized designs. In this paper, a cardiovascular stent was designed, and printed using selective laser melting technology and 316L stainless steel powder of 0-10 µm size. Electrolytic polishing was performed to improve the surface quality of the printed vascular stent, and the expansion behavior of the polished stent was assessed by balloon inflation. The results showed that the newly designed cardiovascular stent could be manufactured by 3D printing technology. Electrolytic polishing removed the attached powder and reduced the surface roughness Ra from 1.36 µm to 0.82 µm. The axial shortening rate of the polished bracket was 4.23% when the outside diameter was expanded from 2.42 mm to 3.63 mm under the pressure of the balloon, and the radial rebound rate was 2.48% after unloading. The radial force of polished stent was 8.32 N. The 3D printed vascular stent can remove the surface powder through electrolytic polishing to improve the surface quality, and show good dilatation performance and radial support performance, which provides a reference for the practical application of 3D printed vascular stent.

Mechanical Properties of Mini-Implants Used in Extra-Radicular Anchorage

ABSTRACT Objective: To evaluate the mechanical properties of mini-implants (MIs) manufactured from stainless steel and compare them with conventional titanium-aluminum-vanadium alloy MIs. Material and Methods: The following groups were formed: G1 (n=24), 8×1.5 mm steel MIs; G2 (n=24), 12×2.0 mm steel MIs; and G3 (n=24), 10×1.5 mm titanium MIs. The 72 MIs were inserted in the infra zygomatic crest region of the maxilla and retromolar trigone in the jaw of 10 pigs. Pull-out, insertion torque, fracture and percussion tests were performed in order to measure the tensile strength, primary stability and fracture strength of MIs. A digital torque gauge was used to measure insertion and fracture torque, a universal mechanical testing machine was used for pull-out testing and a periotest device was used to measure the micromovement of MIs. For morphological and MI component evaluation, scanning electron microscopy (SEM) was performed. D'Agostino & Pearson, Kruskal-Wallis, and Dunn post-hoc and normality tests were used. Results: G2 insertion and fracture torques were significantly higher than G1 and G3 insertion and fracture torques (p<0.05). The pull-out and percussion tests presented similar values among the groups. SEM revealed that the fracture point was predominantly on the fourth thread for steel MIs (G1 and G2) and on the seventh thread for titanium-aluminum-vanadium MIs (G3). Conclusion: The mechanical properties of stainless steel MIs are superior to those of titanium-aluminum-vanadium alloy MIs.

Comparison of Three Tonsillectomy Techniques: Cold Dissection, Monopolar Electrocautery, and Coblation

Abstract Introduction Tonsillectomy is among the most common otolaryngological surgeries. Objective To evaluate and compare three tonsillectomy techniques: cold steel dissection (CSD), monopolar electrocautery (MEC), and coblation. Methods The present study retrospectively reviewed the medical records of patients who underwent tonsillectomy between January 2014 and January 2016. Postoperative visual analog scale (VAS) pain scores, analgesic use, surgical duration, time to return to normal activity, and postoperative bleeding status were noted. Results The CSD group had less analgesic use and shorter return to normal activity than the MEC group (p =0.037 and p < 0.001, respectively). The coblation group had lower VAS pain scores than the MEC group only at 1 hour to 4 hours postsurgery (p <0.016). The postoperative bleeding rate was similar in all groups (p = 0.096). Conclusion Cold steel dissection tonsillectomy is associated with less postoperative pain and shorter recovery than MEC. Coblation is better than MEC in terms of postoperative pain at 1 hour to 4 hours only, whereas CSD is associated with less postoperative pain than coblation at 2 days to 7 days.

A clinical and radiographic comparative evaluation of custom-made zirconia crowns using CAD-CAM and stainless steel crowns in primary molars

Background and Aim of Study: Early childhood caries is a multifactorial disease process affecting children below 71 months of age and continues to be a global health problem. Stainless steel crowns (SSCs) are widely used and are very popular in pediatric dentistry due to its superiority and durability when compared with multisurface amalgam restorations. However, one of the major disadvantages with these crowns is the poor esthetics. Parents often request for a more esthetic alternative to the SSC. Zirconia crowns are one of the tooth-colored full crown restorations currently available for use in primary teeth. These are available as both preformed and custom-made crowns and show excellent esthetics. However, these require extensive tooth preparation with a subgingival finish lines, which would cause gingival trauma and bleeding during the preparation. The present study uses intraoral scanners for making the custom-made zirconia crowns, which will avoid the conventional impressions. Currently, there are no studies available in pediatric dentistry regarding CAD-CAM crowns. Hence, there is a need for the study. Aim: The aim of this study is to clinically evaluate the performance of preformed SSCs and custom-made zirconia crowns in primary molars. To elicit parental and patient satisfaction with respect to preformed SSCs and custom made zirconia crowns and to radiographically compare the interproximal bone height for 1 year. Methods: The patients were selected with purposive sampling. The tooth of interest was prepared according to the crown it would receive. The upper and the lower arch of the tooth receiving custom-made zirconia crown was scanned using an intraoral scanner. The crowns were cemented using Type 1 glass ionomer cement (GIC) (SSC) and resin modified GIC (custom-made zirconia crown). After the crown placement, the patient and the parent's satisfaction was scaled regarding the time taken, comfort, cost of crown, appearance of crown, etc., using a 5-point Likert scale. A baseline radiograph was taken after crown placement. The patient was recalled every 3 months till 1 year for evaluation (loss of retention, loss of proximal contact, gingival inflammation, opposing tooth wear, and marginal integrity). At the end of 1 year, radiographs were taken to check the interproximal bone. Results: After 1 year evaluation of custom-made zirconia crowns and preformed SSCs in primary molars, it was shown that both SSC and zirconia crowns showed good gingival scores but zirconia crown was better than SSC in improving the gingival health. SSCs showed better results with respect to the opposing tooth wear and marginal adaptability. Parents as well as patients preferred a tooth-colored crown as a treatment option. Conclusion: Custom-made zirconia crowns are comparable to the preformed SSCs and they show better gingival scores and excellent color match.

Recent Advance of Stainless Steel Used In Non-active Surgical Implantable Medical Device and Regulatory Perspective / 中国医疗器械杂志

Stainless steel has been widely used in non-active surgical implantable medical device of cardiovascular, orthopedics, dental and ophthalmology. In this paper, we mainly focused on development of stainless steel, as well as the material-related standard evolution. We further summarized the recent advancement of stainless steel use in surgical implantable medical device. Insight and regulatory perspective has been further demonstrated.

Axillary-Axillary Bypass Grafting for Subclavian Steal Syndrome with Progressive Aphasia / 日本心臓血管外科学会雑誌

A 79-years-old female underwent total arch replacement for an aortic arch aneurysm. A postoperative CT scan showed no abnormalities on the anastomotic sites, including the supra-aortic neck vessels. However, 10 months after the operation, she visited our outpatient clinic to complain of left shoulder pain. A CT scan demonstrated complete occlusion of the left subclavian artery, and doppler echography detected a subclavian steal phenomenon. Eleven months after the operation, the patient was transferred to our hospital because of the transient loss of consciousness and progressive aphasia. MRI revealed hyperintensive lesions in the boundary area between the left temporal and occipital lobes, enlarged in a DWI (diffusion-weighted image) with time. Axillary-axillary bypass grafting was performed to suppress the progression of cerebral ischemia caused by a subclavian steal phenomenon. Aphasia seemed to be improved soon after the bypass and diminished on postoperative day 2. The hyperintensive area on DWI regressed, and no other lesion was found on a postoperative MRI. She was discharged without apparent sequelae, including aphasia. We report a successful case of revascularization for subclavian steal syndrome with aphasia.

Modified Hall technique for severely hypomineralized molars. Report of cases / Técnica de Hall modificada para molares severamente hipomineralizados. Reporte de casos / Técnica de Hall modificada para molares severamente hipomineralizados. Relato de caso

Abstract This article reviews the indications, objectives and step by step process of the Modified Hall Technique in the management of primary and permanent molars affected by severe enamel hypomineralization. Scientific based biological principles are discussed in order to provide relevant clinical information for Pediatric and General dentists in order to provide support for the safe use the technique in clinical practice.

Resumen En este artículo se revisan las indicaciones, objetivos y proceso paso a paso de la Técnica de Hall Modificada en el manejo de molares primarios y permanentes afectados por hipomineralización severa del esmalte. Los principios biológicos basados en la evidencia se discuten con el fin de proporcionar información clínica relevante para los odontólogos pediátricos y generales con el fin de proporcionar apoyo para el uso seguro de la técnica en la práctica clínica.

Resumo Neste artigo foram revisadas as indicações, objetivos e o passo a passo da Técnica de Hall Modificada para o manejo de molares decíduos e permanentes afetados pela hipomineralização severa do esmalte. Os princípios biológicos baseados na evidência são discutidos com o objetivo de proporcionar informações clínicas relevantes para odontopediatras e clínicos gerais, a fim de lhes fornecer apoio para o uso seguro da técnica na prática clínica.

Resistance to fracture due to cyclic fatigue of stainless steel manual files and its association to surface roughness / Resistencia a la fractura por fatiga cíclica de las limas manuales de acero inoxidable y su relación con la rugosidad superficial

ABSTRACT The aim of this study was to evaluate the possible association between the roughness of 5 brands of stainless steel endodontic files and their resistance to fracture due to cyclic fatigue. The study includedfive different brands of stainless steel endodontic files: SybroEndo Triple-Flex Files (Kerr, Glendora, USA), Ready Steel K-Flexofile (Dentsply Sirona, Ballaigues, Switzerland), Mani Flexile Files (Mani, Tochigi- Ken, Japan), FKG K-Files (FKG, La Chaux-de-Fonds, Switzerland) and Zipperer Flexicut Files (VDW, Munich, Germany). Twelve files per brand (total 60 files) were evaluated. File surface roughness over an area (Sa) was quantified using a focus variation microscope. Then the files were subject to a cyclical fatigue test to determine the number cycles to fracture due to fatigue and length of fractured fragment. Finally, fractographic analysis was performed using a scanning electron microscope. The electropolished Ready Steel K-Flexofile® files had the highest roughness according to Sa parameters, though they also had the highest resistance to fracture due to cyclic fatigue and the longest fractured fragment. Moderate positive correlation was found between fractured fragment length and roughness. The fractured surface showed characteristics of ductile fracture with cracks and plastic deformation. The electropolished stainless steel Ready Steel K-Flexofile® files werethe most resistant to fracture due to cyclic fatigue even though they had highest surface roughness.

RESUMEN El objetivo del presente estudio fue evaluar la posible asociación entre la rugosidad de 5 marcas de limas endodónticas de acero inoxidable y su resistencia a la fractura por fatiga cíclica. Se incluyeron cinco grupos diferentes de limas endo-dónticas de acero inoxidable: SybroEndo Triple-Flex Files (Kerr, Glendora, EE. UU.), Ready Steel K-Flexofile (Dentsply Sirona, Ballaigues, Suiza), Mani Flexile Files (Mani, Tochigi-Ken, Japón), FKG K-Files (FKG, La Chaux-de-Fonds, Suiza) y Zipperer Flexicut Files (VDW, Munich, Alemania); se evaluaron doce instrumentos por grupo para un total de 60 limas. Mediante un microscopio de variación focal se cuantificó la rugosidad superficial por área (Sa) de los instrumentos, posteriormente fueron sometidos a una prueba de fatiga cíclica donde se determinó el número de ciclos de fractura por fatiga y la longitud del fragmento fracturado. Finalmente, se realizó un análisis fractográfico mediante microscopía electrónica de barrido. Las limas Ready Steel K-Flexofile® con electropulido mostraron el mayor valor de rugosidad en los parámetros Sa; sin embargo, también tenían la mayor resistencia a la fractura por fatiga cíclica y la mayor longitud del fragmento fracturado del instrumento. Además, se encontró una correlación moderada positiva entre la longitud del fragmento fracturado y la rugosidad. La superficie fracturada mostró características de fractura dúctil con grietas y deformación plástica. Las limas Ready Steel K-Flexofile® fabricadas en acero inoxidable con electropulido, fueron más resistentes a la fractura por fatiga cíclica a pesar de tener la mayor rugosidad superficial.

Aplicação de carepa de aço para degradação de 2,4-dinitrofenol por meio de sistema de oxidação avançada do tipo Fenton / Application of steel waste for 2.4-dinitrophenol degradation through Fenton type advanced oxidation system

RESUMO Considerado um poluente prioritário de reconhecida toxicidade e recalcitrância, o 2,4-dinitrofenol (2,4-DNF) presente em águas residuárias dificulta tratamentos convencionais, especialmente os de princípio biológico, como lagoas aeradas e sistema de lodos ativados. Em função de sua potencialidade de transformar a estrutura de poluentes em elementos de capacidade poluidora reduzida, os processos oxidativos avançados (POAs) representam atualmente uma alternativa para o tratamento de efluentes contaminados com compostos dessa natureza. A presente pesquisa teve como objetivo realizar estudos de degradação de 2,4-DNF em solução aquosa por meio de processos de oxidação avançada do tipo Fenton utilizando uma fonte não convencional de ferro na forma de um resíduo siderúrgico (carepa de aço). A condução de um delineamento experimental fundamentado em planejamento fatorial de experimentos revelou que as variáveis quantidade de peróxido de hidrogênio e de carepa influenciaram significativamente a degradação de 2,4-DNF, proporcionando, em condições otimizadas (20 g de carepa, 0,5 mL de H2O2 em pH 3), elevada eficiência na degradação tanto do composto modelo quanto de seus intermediários reacionais, tendo reduzido também a toxicidade aguda medida na forma de inibição de crescimento de E. coli. Ensaios adicionais sugeriram que os mecanismos reacionais pelos quais ocorre a degradação do 2,4-DNF são mediados tanto pela superfície das partículas de carepa quanto pelo ferro lixiviado, caracterizando o processo como uma combinação de oxidação homogênea e heterogênea. Finalmente, ensaios de reusabilidade e operação em reator de fluxo contínuo sugeriram significativa potencialidade do sistema carepa/H2O2.

ABSTRACT Considered a priority pollutant of recognized toxicity and recalcitrance, 2.4-dinitrophenol (2.4-DNP) present in wastewater hinders conventional treatments such as filtration, chemical coagulation, activated sludge system and activated carbon adsorption. Due to the potential of advanced oxidation processes (AOP) to transform the structure of pollutants into elements of reduced pollutant capacity, they presently represent an alternative for the treatment of effluents contaminated with these compounds. The present research aimed to study the degradation of 2.4-DNP in aqueous solution through advanced Fenton-type oxidation processes, using an unconventional source of iron in the form of a steel residue (steel waste). The conduction of an experimental design based on the factorial planning of experiments revealed that the variables hydrogen peroxide quantity and scale significantly influenced 2.4-DNF degradation, providing, under optimized conditions (20 g of steel waste, 0.5 mL of H2O2 at pH 3) high degradation efficiency of both the model compound and its reaction intermediates, as well as reducing acute toxicity, measured as E. coli growth inhibition. Further trials have suggested that the reaction mechanisms by which 2.4-DNF degradation occurs are mediated by both the surface of steel waste particles and the leached iron, characterizing the process as a combination of homogeneous and heterogeneous oxidation. Finally, reusability and continuous flow reactor operation tests suggested the significant potential of the steel waste/ H2O2 system.

The effect of sterilization and disinfection on the physical-mechanical properties of preformed crowns

Introduction: Different sizes of crowns may be tried on children since there is no universal crown size because of distinctions in tooth morphology from one child to other. During the process of trial and error, the crown gets contaminated which needs to be sterilized for reuse of crown. This study was carried out to evaluate the physical–mechanical outcome after the sterilization and disinfection of pediatric preformed crowns. Materials and Methods: In total, sixty crowns consisted of 20 each, stainless steel crowns (SSCs) (3M ESPE), preveneered stainless steel (Kinder Krowns), and Zirconia crowns (Kinder Krowns) which were divided into four groups. G1 in which crowns did not undergo any sterilization, G2 consisted of fast sterilization, similarly G3 was slow sterilization, and G4 underwent chemical disinfection using Korsolex Plus for 15 min. Following sterilization, all the crown samples were observed under a stereomicroscope at ×200 magnification and assessed for color change, crazing, dimensional stability, and fracturing. Post hoc Tukey test and two-way ANOVA were performed for comparison between types of crowns and sterilization methods, with a significance level was set at P < 0.05. Results: There was no color change or fracturing following sterilization among crowns in any of the groups. Highest crazing was noted in stainless steel and the least in Zirconia crowns. Preveneered stainless steel was the most dimensionally stable and SSCs was the least. Conclusion: No color changes and fracture were noted in any type of crowns. Preveneered stainless steel was most dimensionally stable followed by Zirconia and SSCs. Maximum crazing was seen in SSCs and nil in Zirconia.

Comportamiento ante el desgaste por deslizamiento en seco del acero inoxidable súper dúplex en un tribómetro bola sobre anillo / Dry sliding wear behavior of super duplex stainless steel in a ball on ring tribometer

RESUMEN En el presente trabajo se realiza la caracterización del comportamiento ante el desgaste por deslizamiento en seco de un acero inoxidable súper dúplex. Los ensayos fueron desarrollados en un tribómetro tipo bola sobre anillo. Como material del anillo se empleó el acero inoxidable dúplex tipo SAF 2507 sin tratamiento térmico y como material para la bola se usó el acero AISI 52100. Los ensayos se realizaron sin lubricante en condiciones de ambiente (aire), temperatura y humedad estándar de laboratorio. Los parámetros seleccionados, a fin de estudiar sus efectos en el coeficiente desgaste por deslizamiento, fueron: velocidad de deslizamiento (0,9 m/s y 2 m/s), carga normal (9 N, 19 N y 29 N) y distancias de deslizamiento (500 m, 1000 m y 2000 m). Se empleó un diseño experimental de Taguchi con nueve tratamientos y dos réplicas. En la caracterización del acero SAF 2507 se obtuvo valores del coeficiente de desgaste en el intervalo desde 0,19588 x 1012 m2/N hasta 0,72381 x 1012 m2/N, para las condiciones evaluadas. El factor que más afecta el coeficiente de desgaste es la velocidad de deslizamiento. El mecanismo de desgaste identificado para el SAF 2507 es de adhesión y delaminación de alta velocidad.

ABSTRACT In this paper the characterization of the behavior during dry sliding wear of a super duplex stainless steel was performed. The tests were developed in a ball on ring tribometer type. As material of the ring is used the duplex stainless steel type SAF 2507 without heat treatment and as material for the ball is used the steel AISI 52100. Tests were conducted without lubrication in ambient conditions (air), temperature and humidity laboratory standard was used. The parameters selected in order to study its effects on sliding wear coefficient were: sliding speed (0.9 m/s and 2 m/s), normal load (9 N, 19 N and 29 N) and distances slip (500 m, 1000 m and 2000 m). Taguchi experimental design with nine treatments and two replicates was used. In the characterization of steel SAF 2507 wear coefficient values was obtained in the range from 0.19588 x 10-12 m2/N to 0.72381 x 10-12 m2/N, for the conditions tested. The factor that most affects the wear coefficient is the sliding velocity. The wear mechanism identified for the SAF 2507 was adhesion and high speed delamination.

Clinical application of Taylor spatial frame in adjustment of lower extremity force line of knee medial compartmental osteoarthritis / 中国修复重建外科杂志

Objective: To explore the safety and effectiveness of Taylor spatial frame (TSF) in the treatment of medial compartmental osteoarthritis (MCOA) of the knee and the adjustment of the lower extremity force line at the same time. Methods: The clinical data of 30 patients with MCOA who underwent high tibial osteotomy (HTO) between October 2016 and April 2017 were retrospectively analyzed. According to the different fixation methods, they were divided into external fixation group (TSF external fixation, 16 cases) and internal fixation group (locking steel plate internal fixation, 14 cases). There was no significant difference between the two groups in gender, age, side, disease duration, mechanical femur tibia angle (MFTA), and other general data ( P>0.05). The operation time and intraoperative blood loss of the two groups were recorded and compared; MFTA was used to evaluate the recovery of the lower extremity force line at last follow-up; Hospital for Special Surgery (HSS) score was used to evaluate the clinical effecacy before operation and at 2 weeks, 1 month, and 3 months after operation. Results: The operation time and intraoperative blood loss of external fixation group were significantly less than those of internal fixation group ( P0.05). Conclusion: TSF has unique advantages in HTO treatment of MCOA patients and correction of lower extremity force line, such as shorter operation time, less bleeding, firm fixation, and less complications. It can accurately adjust the lower extremity force line after operation and has good effectiveness. It is an effective and safe fixation method.

Meta-analysis of the effect of double endobutton and clavicular hook plate on the treatment of acromioclavicular dislocation / 中国组织工程研究

OBJECTIVE: Because the double Endobutton plate has more advantages than the clavicle hook plate in the treatment of acromioclavicular joint dislocation, and the trauma is small; it does not need to be removed through secondary surgery. Thus, it has been widely used in clinical practice in recent years. Meta-analysis was used to investigate whether there were differences in the treatment of acromioclavicular dislocation between double Endobutton plate and clavicle hook plate so as to provide effective guidance for clinical treatment. METHODS: The database Cochrane library, PubMed, EBSCO, CNKI, VIP and Wanfang were searched from the database inception to January 2020. All the literatures related to the treatment of acromioclavicular dislocation with double Endobutton plate and clavicle hook plate were collected. The literatures were selected according to the inclusion and exclusion criteria to extract the data and to carry out the relevant analysis. The literatures that meet the requirements were screened out. The quality of the selected relevant literatures was assessed. All outcome indicators were analyzed by RevMan 5.3 software. RESULTS: (1) A total of 38 articles were included, and the total number of cases was 2 199, of which 1 035 cases were in the double Endobutton plate group and 1 164 cases were in the clavicle hook plate group. (2) The results showed that the double Endobutton plate group was superior to the clavicle hook plate group in the excellent and good rate [RR=1.19, 95%CI(1.13, 1.26), P < 0.000 01], operation time [MD=10.54, 95% CI(6.09, 15.00), P < 0.000 01], intraoperative blood loss [MD=-14.83, 95%CI(-20.54,-9.13), P < 0.000 01], hospitalization time [MD=-1.44, 95%CI(-2.65,-0.23), P=0.02], incision length [MD=-2.87, 95%CI (-3.60, -2.14), P < 0.000 01], hospitalization cost [MD=-2 442.10, 95% CI(-4 466.34, -417.86), P=0.02], shoulder pain after operation [RR=0.34, 95%CI(0.22, 0.53), P < 0.000 01], visual analogue scale score [MD=-0.85, 95% CI(-1.28, -0.41), P=0.000 2], final Constant-Murley score at 6 months postoperatively [MD=8.82, 95%CI(1.91, 15.72), P=0.01; MD=6.66, 95%CI(4.46, 8.86), P < 0.000 01]CONCLUSION: The treatment of Rockwood III type and above acromioclavicular joint dislocation with double Endobutton plate is superior to that clavicular hook plate. It has the advantages of short operation time, less intraoperative blood loss, less trauma, short hospitalization time and less cost, and good functional recovery of shoulder joint after operation.

Intramedullary nail fixation versus plate fixation in the treatment of displaced midshaft clavicular fractures in adults: A meta-analysis / 中国组织工程研究

OBJECTIVE: At present, many studies have proved that intramedullary nail and steel plate internal fixation is a better way to treat displaced midshaft clavicular fracture. However, there are relatively few comparative studies on the advantages and disadvantages of the two methods, and there are still many controversies. Through the meta-analysis of related literature, the efficacy and safety of intramedullary nail and steel plate in the treatment of adult displaced midshaft clavicular fracture were systematically evaluated. METHODS: Through computer retrieval of PubMed, Embase, Cochrane Library, CNKI, Wanfang and VIP databases from the inception to January 2020, the literature of randomized controlled trials meeting the inclusion and exclusion criteria of intramedullary nail and steel plate in the treatment of adult displaced midshaft clavicular fracture was collected and screened, and the quality evaluation and data extraction were carried out. The operation time, incision length and upper limb function score, Constant-Murley score, and fracture healing time were used as the evaluation indexes of meta-analysis. Meta-analysis was performed using ReMan 5.3 software. RESULTS: (1) Eight valuable articles were retrieved, among which 283 patients were treated with intramedullary nail and 271 patients were treated with steel plate internal fixation. (2) The meta-analysis results showed that the intramedullary nail group was superior to the steel plate group in terms of operation time [MD=-19.63, 95%CI(-22.72,-16.54)], incision length [MD=-3.31, 95%CI(-5.78,-0.85)], and fracture healing time [MD=-1.53, 95%CI(-2.73,-0.33)]. (3) No significant difference was found in upper limb function score [MD=-1.91, 95%CI(-5.48, 1.66)] and Constant-Murley score [MD=-0.58, 95%CI(-4.63, 3.47) between the intramedullary nail group and the steel plate group after surgery. CONCLUSION: The results of meta-analysis showed that intramedullary nail was superior to steel plate in the operation time, incision length and fracture healing time in the treatment of displaced midshaft clavicular fracture. The above results can provide evidence for clinical use of intramedullary nail instead of steel plate internal fixation in the treatment of displaced midshaft clavicular fracture.