913 research outputs found
Алгоритм определения оптимального числа волокон используемых при внутритканевой фотодинамической терапии рака молочной железы на основании диффузионного уравнения
It is essential in interstitial Photodynamic therapy (iPDT) treatment planning to ensure a homogeneous distribution within a tumor volume using cylindrical diffusing fibers while keeping the surrounding tissue intact. Light distribution is simulated through two algorithms based on the diffusion equation assuming diffusers as light sources. The first algorithm analyzes the diffusion equation and studies the effects of different variables (optical properties, delivered power, diffuser length, and position). Next, optical properties of breast were applied to estimate the volume that receives accepted light dose from one diffuser. In the second algorithm, multiple diffusers were simulated in order to find the relation between the volume and the number of required diffusers which are needed to cover cubical or cylindrical volume with sufficient light dose. Throughout this study, real values of optical properties, clinical laser power, and treatment time were considered to evaluate sufficient light doses. This study is in agreement with previous works in that optical properties are the major factors influencing light distribution in iPDT. It is shown that for a homogeneous phantom mimicking breast cancer and cubical or cylindrical shape, the number of required fibers N equal W×L or D2 respectively.При планировании внутритканевой фотодинамической терапии (iPDT ) с использованием цилиндрических диффузных волокон важно обеспечить однородное распределение света по всему объему опухоли, сохранив при этом целостность окружающей ткани. Авторы данной статьи смоделировали распределение света с помощью двух алгоритмов, основанных на уравнении диффузии, в которых в качестве источников света используются цилиндрические диффузоры. Первый алгоритм анализирует уравнение диффузии и изучает влияние различных переменных (оптических свойств источника, применяемой мощности, длины диффузора и его положения). Затем были использованы параметры оптических свойств молочной железы для оценки объема, который рассчитывает световую дозу от одного диффузора. Во втором алгоритме было смоделировано несколько рассеивателей для нахожде ния соотношения между объемом и количеством рассеивателей, необходимых для покрытия кубического или цилиндрического объема достаточной световой дозой. На протяжении всего этого исследования рассматривались реальные значения оптических свойств, клинической мощности лазера и времени лечения для оценки достаточных световых доз. Это исследование согласуется с предыдущими работами в том, что оптические свойства являются основными факторами, влияющими на распределение света при iPDT. Показано, что, для однородного фантома, имитирующего рак молочной железы, кубической или цилиндрической формы, количество требуемых волокон N равно W×L или D2 , соответственно
The Mediating Role of Operations Management Practices on the Relationship Between the Dimensions of Manufacturing Flexibility and Competitiveness
Purpose: The aim of this study is to examine knowing the real role and impact of manufacturing flexibility on competitiveness through operations management practices, which is to determine the role and impact of manufacturing flexibility on competitiveness directly in the General Company for the Battery Industry. On the other hand, identifying the indirect role of flexible manufacturing systems in enhancing competitiveness.
Theoretical framework: The main purpose of the theoretical framework is to identify all the dimensions and variables included in the current study, and thus form a deep scientific view of the study and its variables.
Design/methodology/approach: field coexistence, personal interviews, and classification of data and information obtained in the questionnaire were adopted as the main tool used in the research and for a sample of 74 observations. Structural equations modelling was used to analyze the data using the programs (SPSS24, AMOS23).
Findings: the research reached important results that represent The most prominent of these is the significant impact of manufacturing flexibility in enhancing the competitiveness of the battery manufacturing company, and this effect is reinforced by improving operations management practices by the company.
Research, Practical & Social implications: The research was conducted in this company because it requires scientific research capable of solving many of its problems as a result of increased competition in the market, as well as the continuation of this company in production despite the cessation of many other companies as a result of.
Value: It stems from a vital issue related to aimed at a better future in terms of Operations Management Practices, Flexibility of Manufacturing, Operations Management Practices, and Competitiveness, especially after the crisis that led to a significant decline in the level of performance of organizations
Mismatch Repair Proteins (MLH1, MSH2, MSH6, and PMS2) Immunohistochemical Expression and Microsatellite Instability in Endometrial Carcinoma
BACKGROUND: Endometrial cancer (EC) is the fourth most common female cancer worldwide constituting 7% of cancer in women. It is a disease of older, postmenopausal women. The most of these patients have an identifiable source of excess estrogen, while in a small subset the pathogenesis is related to mismatch repair abnormality and lynch syndrome (LC). Mismatch repair behave as tumor suppressors and the most clinically relevant include MLH1, MSH2, MSH6, and PMS2. mutations in mismatch repair (MMR) results in a strong mutator phenotype known as microsatellite instability, which is a hallmark of LC-associated cancers.
AIM: The aim of the study was to study microsatellite instability in endometrial cancer using the immunohistochemical expression of mismatch repair proteins (MLH1, MSH2, MSH6 and PMS2).
MATERIAL AND METHODS: Sixty EC cases were studied using MLH-1, MSH-2, MSH-6, and PMS-2 immunohistochemistry and their expression was correlated with different clinicopathologic parameters.
RESULTS: A statistically significant relationship exists between MMR immunohistochemistry (IHC) proteins and tumor grade. Intact MMR proteins profile was associated with the lower tumor grade (31.3% were Grade 1 and 46.9% were Grade 2). Combined loss of MLH1/PMS2, combined loss of MSH2/MSH6, and isolated loss of PMS2 were also associated with the lower tumor grade while isolated loss of MSH6 was associated with the high tumor grade. However, no statistically significant correlation was found between MMR IHC proteins expression and the age of patients; tumor histopathological types, or FIGO stage.
CONCLUSION: A statistically significant correlation between the tumor grade of EC cases and the MMR IHC proteins was found. Further studies are recommended to assess correlation between MMR proteins defect and different clinicopathological parameters of endometrial carcinoma
Screening of yeasts for production of xylitol fromd-xylose and some factors which affect xylitol yield inCandida guilliermondii
The ability to convertd-xylose to xylitol was screened in 44 yeasts from five genera. All but two of the strains produced some xylitol with varying rates and yields. The best xylitol producers were localized largely in the speciesCandida guilliermondii andC. tropicalis. Factors affecting xylitol production by a selectedC. guilliermondii strain, FTI-20037, were investigated. The results showed that xylitol yield by this strain was affected by the nitrogen source. Yield was highest at 30–35°C, and could be increased with decreasing aeration rate. Using high cell density and a defined medium under aerobic conditions, xylitol yield byC. guilliermondii FTI-20037 from 104 g/ld-xylose was found to be 77.2 g/l. This represented a yield of 81% of the theoretical value, which was computed to be 0.9 mol xylitol per mold-xylose
Combined tools for surgical case packages contents and cost optimization: a preliminary study
This paper presents a solution proposal based on mathematical and statistical tools to optimize Surgical Case Packages of an Operating Room (OR) in a Portuguese public hospital that it is the most complex environment in a hospital. In this particular hospital, more than 27000 surgeries/year are performed, employing, sometimes, misadjusted composition of standard surgical packages and non-optimized grouping of surgical instruments. Problem consequences are, among others, high transport of various surgical cases packages; high number of open cases and delays in surgical times following surgery. These type of problems are waste that do not add value to the service in the context of Lean Healthcare and must be eliminated using the most suitable tools. After the analysis, different tools were used: combinatorial analysis to optimize surgical cases composition and statistical analysis to identify the instruments usage and surgical basic case patterns. An optimization model was developed which produced a sterilizing initial solution of 135.24€. By identifying the most commonly employed instruments, it was concluded that some instruments have never been used and others rarely and some patterns were identified. The results achieved were based on minor sample and in a form of data collection that needs some adjustments.The authors want to acknowledge the Portuguese public hospital involved and to the ESGI initiative. The authors also would like to express their acknowledgments to national funds by COMPETE: POCI-01-0145-FEDER-007043 and FCT - Fundacao para a Ciencia e Tecnologia within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio
Efeitos do treinamento aeróbio e resistido combinados na variabilidade da frequência cardíaca em mulheres na menopausa
Modelo de Estudo: Ensaio clínico controlado. Objetivo: Verificar a resposta de 16 semanas do treinamento aeróbio e resistido combinado sobre a modulação autonômica em mulheres na menopausa.Métodos: 17 mulheres foram divididas em dois grupos: grupo treino (GT: n=11) e grupo controle (GC:n=6). As variáveis de composição corporal foram estimadas pela absorptiometria radiológica de dupla energia. A modulação autonômica foi avaliada pela variabilidade da frequência cardíaca usando índices lineares. O protocolo de treinamento consistiu em 16 semanas, por 50 minutos de treinamento resistido e 30 minutos de treinamento aeróbio. Resultados: Para o GT houve incremento do índice rMSSD(ms)(pre:17,4±3,7 e pos:24,8±13,1, p<0,045), aumento dos intervalos entre batimentos cardíacos consecutivos (pre:891,2±80,2 e pos:974,1±71,4, p<0,003) e dos valores de frequência cardíaca(bpm) (pre:68,1±6,4 e pos:62,0±4,7, p<0,003), para os índices espectrais em unidades normalizadas, houve redução de LF(pre:52,2±13,1 e pos:44,5±12,4, p<0,025) e incremento de HF (pre:47,8±13,3 e pos:55,5±12,4, p<0,025).Não houve diferenças significantes para o GC. Conclusão: o treinamento aeróbio e resistido combinado promoveu benefícios sobre a modulação autonômica em mulheres na menopausa.Model of the study: Controlled clinical trial. Objective: To verify the effects of 16 weeks of combined aerobic and resistance training on cardiac autonomic modulation in menopausal women. Methods: 17 menopausal women were divided into two groups: the training group (TG: n=11) and control group (CG:n=6). The body composition variables were estimated using dual-energy X-ray absorptiometry. The cardiac autonomic modulation was evaluated by heart rate variability using linear indexes. The training protocol consisted of 16 weeks of 50 minutes of resistance training and 30 minutes of aerobic training. Results: For the TG there was an increase in the rMSSD(ms) index (pre:17,4±3,7 and post:24,8±13,1,p<0,045), an increase in the duration of the intervals between the cardiac beats(ms) (pre:891,2±80,2 and post:974,1±71,4, p<0,003) and in the values of heart rate(bpm) (pre:68,1±6,4 and post:62,0±4,7, p<0,003), additionally for the spectral indexes in normalized units, changes for LF (pre:52,2±13,1 and post:44,5±12,4, p<0,025) and HF (pre:47,8±13,3 and post:55,5±12,4, p<0,025) were noticed, demonstrating increased parasympathetic and reduced sympathetic. There were no significant differences to CG. Conclusion: combined aerobic and resistance training promoted benefits to the autonomic modulation in menopausal women
Two-Dimensional Electronic Spectroscopy of Chlorophyll a: Solvent Dependent Spectral Evolution
The interaction of the monomeric chlorophyll Q-band electronic transition with solvents of differing physical-chemical properties is investigated through two-dimensional electronic spectroscopy (2DES). Chlorophyll constitutes the key chromophore molecule in light harvesting complexes. It is well-known that the surrounding protein in the light harvesting complex fine-tunes chlorophyll electronic transitions to optimize energy transfer. Therefore, an understanding of the influence of the environment on the monomeric chlorophyll electronic transitions is important. The Q-band 2DES is inhomogeneous at early times, particularly in hydrogen bonding polar solvents, but also in nonpolar solvents like cyclohexane. Interestingly this inhomogeneity persists for long times, even up to the nanosecond time scale in some solvents. The reshaping of the 2DES occurs over multiple time scales and was assigned mainly to spectral diffusion. At early times the reshaping is Gaussian-like, hinting at a strong solvent reorganization effect. The temporal evolution of the 2DES response was analyzed in terms of a Brownian oscillator model. The spectral densities underpinning the Brownian oscillator fitting were recovered for the different solvents. The absorption spectra and Stokes shift were also properly described by this model. The extent and nature of inhomogeneous broadening was a strong function of solvent, being larger in H-bonding and viscous media and smaller in nonpolar solvents. The fastest spectral reshaping components were assigned to solvent dynamics, modified by interactions with the solute
Sources and Mitigation of Harmonics in Industrial Electrical Power Systems: State of the Art
Abstract -Power systems are designed to operate at frequencies of 50 Hz or 60Hz. However, certain types of loads produce currents and voltages with frequencies that are integer multiples of the 50 or 60 Hz fundamental frequency. These higher frequencies represent a form of electrical network pollutions known as ''power system harmonics''. This paper presents an extensive literature review in the petrochemical sector for the power system harmonics such as harmonics fundamentals, harmonics harmful effects on various electrical equipment, harmonic distortion limits and harmonic mitigation techniques. This paper is intended as a guide for those interested in this problem or intending to perform further researches in this area
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