Pub Date : 2015-04-20DOI: 10.1109/ENBENG.2015.7088810
Ana C. D. Pfluck, Dragana P. C. de Barros, Clara Lopes, L. Fonseca
Miniemulsions are heterophase systems consisting of small, stable and narrowly distributed droplets in a continuous phase [1]. Recently this system shows a high potential for different biocatalytic reactions, as environmentally friendly reaction media consisting 80% of water [2]. The other important factor is enormous interfacial area, readily available for interfacial catalysis. The systems are obtained using high shear force, in particular, ultrasound. For a typical oil-in-water miniemulsion, an oil phase (e.g. substrates), a hydrophobic agent (e.g. hexadecane), an emulsifier (usually nonionic surfactant), and water are homogenised to obtain monodisperse droplets in the size range up to 500 nm[1,2]. The objective of present work was to obtain a stable miniemulsion system through optimization of conditions of ultrasonication using different solvents (oil phase). The effect of six solvents (hexane, cyclohexane, isooctane, decane, hexadecane and acetonitrile) on miniemulsion stability was explored. In order to establish a reproducible dispersion procedure, power and amplitude of ultrasonication was varied and it's relation with the droplet size was observed. The influence of the ultrasonication time was also evaluated on miniemulsion stability. Droplet size and distribution factor were characterized by dynamic light scattering. The results show that the particle size varied between 320 and 630 nm, except for the systems with the cyclohexane in which a higher size was obtained. The best result was achieved with 50% of amplitude and 30W of power using hexane as a solvent. The phase separation was observed for the cyclohexane and acetonitrile miniemulsion systems. It could be due to the droplet size (cyclohexane) or acetonitrile hydrophilic character.
{"title":"Optimization of miniemulsion process using different solvents","authors":"Ana C. D. Pfluck, Dragana P. C. de Barros, Clara Lopes, L. Fonseca","doi":"10.1109/ENBENG.2015.7088810","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088810","url":null,"abstract":"Miniemulsions are heterophase systems consisting of small, stable and narrowly distributed droplets in a continuous phase [1]. Recently this system shows a high potential for different biocatalytic reactions, as environmentally friendly reaction media consisting 80% of water [2]. The other important factor is enormous interfacial area, readily available for interfacial catalysis. The systems are obtained using high shear force, in particular, ultrasound. For a typical oil-in-water miniemulsion, an oil phase (e.g. substrates), a hydrophobic agent (e.g. hexadecane), an emulsifier (usually nonionic surfactant), and water are homogenised to obtain monodisperse droplets in the size range up to 500 nm[1,2]. The objective of present work was to obtain a stable miniemulsion system through optimization of conditions of ultrasonication using different solvents (oil phase). The effect of six solvents (hexane, cyclohexane, isooctane, decane, hexadecane and acetonitrile) on miniemulsion stability was explored. In order to establish a reproducible dispersion procedure, power and amplitude of ultrasonication was varied and it's relation with the droplet size was observed. The influence of the ultrasonication time was also evaluated on miniemulsion stability. Droplet size and distribution factor were characterized by dynamic light scattering. The results show that the particle size varied between 320 and 630 nm, except for the systems with the cyclohexane in which a higher size was obtained. The best result was achieved with 50% of amplitude and 30W of power using hexane as a solvent. The phase separation was observed for the cyclohexane and acetonitrile miniemulsion systems. It could be due to the droplet size (cyclohexane) or acetonitrile hydrophilic character.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123123558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-20DOI: 10.1109/ENBENG.2015.7088824
Nuno Saraiva Santos, Sonia C. P. Sousa, P. Crespo, Pedro Cavaleiro Miranda, R. Salvador, J. Silvestre
Repetitive transcranial magnetic stimulation (rTMS) is an up-and-coming, noninvasive technique that holds therapeutic promise in a range of neuropsychiatric and neurological diseases. In rTMS, a time-varying magnetic field induces an electric current in the brain. Since its introduction close to 30 years ago, numerous studies have widely recognised it in the research or treatment of several diseases (e.g. epilepsy, Parkinson's disease, stroke or neuropathic pain). rTMS treatments already occurring in the USA include psychiatric conditions like major depression (approved in 2008), and migraine (approved in 2013). Nevertheless, throughout several years it has been found that the stimulation of subcortical brain structures is inaccessible with standard rTMS equipment. Accessing such deep-brain regions may potentially result in the improvement of a variety of neuropsychiatric and neurological disorders. The design of TMS coils to stimulate deep brain targets is limited by the rapid attenuation of the electric field in depth. This is mainly due to the physical limiting effect arising from the presence of surface discontinuities. To the best of our knowledge the Hesed coil represents the state of the art of clinical deep-brain TMS. Nonetheless, there is no configuration able of producing an effective field at the very center of the brain. We have proposed a TMS system termed orthogonal configuration that is capable of reaching the very center of a spherical brain phantom (at 10-cm depth) with 58% strength in respect to the surface maximum. The high, external magnetic field of this configuration was designed so that it is incapable of inducing heart fibrillation in the patient by four orders of magnitude in respect to its threshold. Nevertheless, Comsol® AC/DC simulations show that a system operator positioned sideways, 10 cm apart from the orthogonal configuration will experience an induced current density in his heart of 0.7 A/m2 (heart fibrillation threshold is 1 A/m2). Only 3.4 m away from the orthogonal configuration will a heart current density of 0.001 A/m2 be achieved. In this work we focus on the shielding aspects necessary to install an orthogonal TMS system providing full safety to patient and any of its operators. For that, we have measured the TMS signal attenuation induced by an iron or aluminium slab of material positioned between a TMS coil and a current density sensor located inside a cylinder container filled with a saline solution (7 S/m, i.e. 5% w/v of NaCl in water). Simulations combined with experimental results show that a simple 25-mm-thick slab of aluminium surrounding five walls of the orthogonal TMS system (positioned 40 cm apart from its edges) is enough to achieve a current density in the heart of any operator inferior to 0.001 A/m2, i.e. at least three orders of magnitude below fibrillation threshold. This allows us to conclude on the viability of implementing an R&D orthogonal TMS system in the near future.
重复经颅磁刺激(rTMS)是一种新兴的无创技术，在一系列神经精神和神经系统疾病中具有治疗前景。在rTMS中，时变磁场在大脑中诱导电流。自近30年前引入以来，许多研究已在几种疾病(如癫痫、帕金森病、中风或神经性疼痛)的研究或治疗中广泛认可它。在美国已经出现的rTMS治疗包括精神疾病，如重度抑郁症(2008年批准)和偏头痛(2013年批准)。然而，在过去的几年里，人们发现标准的rTMS设备无法刺激皮质下的大脑结构。进入这样的深部脑区域可能会潜在地改善各种神经精神和神经系统疾病。刺激深部脑目标的TMS线圈的设计受到深部电场快速衰减的限制。这主要是由于表面不连续引起的物理限制效应。据我们所知，Hesed线圈代表了临床深部脑经颅磁刺激的最新技术。然而，目前还没有一种结构能够在大脑的最中心产生有效的磁场。我们提出了一种称为正交结构的经颅磁刺激系统，该系统能够到达球形脑幻影的中心(在10厘米深度)，相对于表面的最大强度为58%。这种结构的高外部磁场被设计成不能在病人的阈值上诱发四个数量级的心脏颤动。尽管如此，Comsol®AC/DC模拟表明，系统操作员侧着放置，距离正交配置10厘米，他的心脏将感受到0.7 a /m2的感应电流密度(心脏颤动阈值为1 a /m2)。距离正交配置仅3.4 m，心脏电流密度将达到0.001 a /m2。在这项工作中，我们重点关注安装正交TMS系统所需的屏蔽方面，为患者及其任何操作人员提供充分的安全。为此，我们测量了由放置在TMS线圈和电流密度传感器之间的铁板或铝板材料引起的TMS信号衰减，该传感器位于充满盐水溶液(7 S/m，即水中5% w/v的NaCl)的圆柱形容器内。模拟结合实验结果表明，一个简单的25毫米厚的铝板围绕着正交TMS系统的五面墙(距离边缘40厘米)，足以在任何操作员的心脏中实现低于0.001 a /m2的电流密度，即至少比纤颤阈值低三个数量级。这使我们能够在不久的将来得出实施研发正交TMS系统的可行性。
{"title":"Shielding the magnetic field from a transcranial stimulator using aluminium and iron: Simulation and experimental results","authors":"Nuno Saraiva Santos, Sonia C. P. Sousa, P. Crespo, Pedro Cavaleiro Miranda, R. Salvador, J. Silvestre","doi":"10.1109/ENBENG.2015.7088824","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088824","url":null,"abstract":"Repetitive transcranial magnetic stimulation (rTMS) is an up-and-coming, noninvasive technique that holds therapeutic promise in a range of neuropsychiatric and neurological diseases. In rTMS, a time-varying magnetic field induces an electric current in the brain. Since its introduction close to 30 years ago, numerous studies have widely recognised it in the research or treatment of several diseases (e.g. epilepsy, Parkinson's disease, stroke or neuropathic pain). rTMS treatments already occurring in the USA include psychiatric conditions like major depression (approved in 2008), and migraine (approved in 2013). Nevertheless, throughout several years it has been found that the stimulation of subcortical brain structures is inaccessible with standard rTMS equipment. Accessing such deep-brain regions may potentially result in the improvement of a variety of neuropsychiatric and neurological disorders. The design of TMS coils to stimulate deep brain targets is limited by the rapid attenuation of the electric field in depth. This is mainly due to the physical limiting effect arising from the presence of surface discontinuities. To the best of our knowledge the Hesed coil represents the state of the art of clinical deep-brain TMS. Nonetheless, there is no configuration able of producing an effective field at the very center of the brain. We have proposed a TMS system termed orthogonal configuration that is capable of reaching the very center of a spherical brain phantom (at 10-cm depth) with 58% strength in respect to the surface maximum. The high, external magnetic field of this configuration was designed so that it is incapable of inducing heart fibrillation in the patient by four orders of magnitude in respect to its threshold. Nevertheless, Comsol® AC/DC simulations show that a system operator positioned sideways, 10 cm apart from the orthogonal configuration will experience an induced current density in his heart of 0.7 A/m2 (heart fibrillation threshold is 1 A/m2). Only 3.4 m away from the orthogonal configuration will a heart current density of 0.001 A/m2 be achieved. In this work we focus on the shielding aspects necessary to install an orthogonal TMS system providing full safety to patient and any of its operators. For that, we have measured the TMS signal attenuation induced by an iron or aluminium slab of material positioned between a TMS coil and a current density sensor located inside a cylinder container filled with a saline solution (7 S/m, i.e. 5% w/v of NaCl in water). Simulations combined with experimental results show that a simple 25-mm-thick slab of aluminium surrounding five walls of the orthogonal TMS system (positioned 40 cm apart from its edges) is enough to achieve a current density in the heart of any operator inferior to 0.001 A/m2, i.e. at least three orders of magnitude below fibrillation threshold. This allows us to conclude on the viability of implementing an R&D orthogonal TMS system in the near future.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124726224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-20DOI: 10.1109/ENBENG.2015.7088827
B. Cunha, P. Sampaio, C. Calado
Summary form only given. Bacterial infections and the fight against them have been one of the major concerns of mankind since the dawn of time. During the `golden years' of antibiotic discovery, during the 1940-90s, it was thought that the war against infectious diseases had been won. However currently, due to the drug resistance increase, associated with the inefficiency of discovering new antibiotic classes, infectious diseases are again a major public health concern. A potential alternative to antibiotic treatments may be the antimicrobial photodynamic inactivation (PDI) therapy. To date no indication of antimicrobial PDI resistance development has been reported. However the PDI protocol depends on the bacteria species [1], and in some cases on the bacteria strains, for instance Staphylococcus aureus [2]. Therefore the development of PDI monitoring techniques for diverse bacteria strains is critical in pursuing further understanding of such promising alternative therapy. The present works aims to evaluate Fourier-Transformed-Infra-Red (FT-IR) spectroscopy to monitor the PDI of two model bacteria, a gram-negative (Escherichia coli) and a gram-positive (S. aureus) bacteria. For that a high-throughput FTIR spectroscopic method was implemented as generally described in Scholz et al. [3], using short incubation periods and microliter quantities of the incubation mixture containing the bacteria and the PDI-drug model the known bactericidal tetracationic porphyrin 5,10,15,20-tetrakis (4-N, N, Ntrimethylammoniumphenyl)-porphyrin p-tosylate (TTAP4+). In both bacteria models it was possible to detect, by FTIR-spectroscopy, the drugs effect on the cellular composition either directly on the spectra or on score plots of principal component analysis. Furthermore the technique enabled to infer the effect of PDI on the major cellular biomolecules and metabolic status, for example the turn-over metabolism. In summary bacteria PDI was monitored in an economic, rapid (in minutes), high-throughput (using microplates with 96 wells) and highly sensitive mode resourcing to FTIR spectroscopy, which could serve has a technological basis for the evaluation of antimicrobial PDI therapies efficiency.
只提供摘要形式。自古以来，细菌感染及其防治一直是人类关注的主要问题之一。在抗生素发现的“黄金年代”，即20世纪40年代至90年代，人们认为对抗传染病的战争已经取得了胜利。然而，目前，由于耐药性的增加，与发现新抗生素类别的效率低下有关，传染病再次成为一个主要的公共卫生问题。抗菌光动力失活(PDI)治疗可能是抗生素治疗的潜在替代方案。到目前为止，没有抗菌剂PDI耐药性发展的迹象报告。然而，PDI方案取决于细菌种类[1]，在某些情况下取决于细菌菌株，例如金黄色葡萄球菌[2]。因此，开发多种细菌菌株的PDI监测技术对于进一步了解这种有前途的替代疗法至关重要。目前的工作旨在评估傅里叶变换红外(FT-IR)光谱来监测两种模式细菌的PDI，一种革兰氏阴性(大肠杆菌)和一种革兰氏阳性(金黄色葡萄球菌)细菌。为此，采用Scholz等人[3]中所描述的高通量FTIR光谱方法，使用短孵育时间和微升量的含细菌孵育混合物和pdi -药物模型，即已知的杀菌四价卟啉5,10,15,20-四价(4-N, N, ntrimethylammonumphenyl)-卟啉对tosylate (TTAP4+)。在这两种细菌模型中，通过ftir光谱可以直接在光谱上或在主成分分析的得分图上检测药物对细胞组成的影响。此外，该技术能够推断PDI对主要细胞生物分子和代谢状态的影响，例如翻转代谢。综上所述，采用经济、快速(分钟)、高通量(96孔微孔板)、高灵敏度的FTIR光谱模式监测细菌PDI，可为评价抗菌PDI治疗效果提供技术基础。
{"title":"Development of a high-throughput monitoring technique of bacteria photodynamic inactivation","authors":"B. Cunha, P. Sampaio, C. Calado","doi":"10.1109/ENBENG.2015.7088827","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088827","url":null,"abstract":"Summary form only given. Bacterial infections and the fight against them have been one of the major concerns of mankind since the dawn of time. During the `golden years' of antibiotic discovery, during the 1940-90s, it was thought that the war against infectious diseases had been won. However currently, due to the drug resistance increase, associated with the inefficiency of discovering new antibiotic classes, infectious diseases are again a major public health concern. A potential alternative to antibiotic treatments may be the antimicrobial photodynamic inactivation (PDI) therapy. To date no indication of antimicrobial PDI resistance development has been reported. However the PDI protocol depends on the bacteria species [1], and in some cases on the bacteria strains, for instance Staphylococcus aureus [2]. Therefore the development of PDI monitoring techniques for diverse bacteria strains is critical in pursuing further understanding of such promising alternative therapy. The present works aims to evaluate Fourier-Transformed-Infra-Red (FT-IR) spectroscopy to monitor the PDI of two model bacteria, a gram-negative (Escherichia coli) and a gram-positive (S. aureus) bacteria. For that a high-throughput FTIR spectroscopic method was implemented as generally described in Scholz et al. [3], using short incubation periods and microliter quantities of the incubation mixture containing the bacteria and the PDI-drug model the known bactericidal tetracationic porphyrin 5,10,15,20-tetrakis (4-N, N, Ntrimethylammoniumphenyl)-porphyrin p-tosylate (TTAP4+). In both bacteria models it was possible to detect, by FTIR-spectroscopy, the drugs effect on the cellular composition either directly on the spectra or on score plots of principal component analysis. Furthermore the technique enabled to infer the effect of PDI on the major cellular biomolecules and metabolic status, for example the turn-over metabolism. In summary bacteria PDI was monitored in an economic, rapid (in minutes), high-throughput (using microplates with 96 wells) and highly sensitive mode resourcing to FTIR spectroscopy, which could serve has a technological basis for the evaluation of antimicrobial PDI therapies efficiency.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129692059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-20DOI: 10.1109/ENBENG.2015.7088821
A. Nunes, M. Patrício, F. Alves
Summary form only given. Internal organ dose estimates have always depended on standard reference models that mimic the interior and exterior anatomical features of the human body. These models are based on 20-30 year-old and healthy average European and North American populations, their organ masses and body weights and heights corresponding to the 50th percentile data [1]. However, if an individual patient deviates greatly from the reference anatomy, the use of a standard phantom can hinder the precision of the dose assessment being performed. Published anthropometric studies [2] suggest that the Portuguese population deviates from the parameters defined for the reference dosimetric models [3]. The general aim of the present research is to develop and validate two new anthropomorphic models of the human body (one male and one female), that specifically represent Portuguese adult patients who undergo PET/CT examinations. A secondary goal of this project is to profile the Portuguese patients undergoing PET/CT examinations, in respect to their age and internal and external anatomical features. In order to achieve this goal, anthropometric patient data regarding 18F-FDG PET/CT examinations performed at the Institute of Nuclear Sciences Applied to Health (ICNAS) were collected and analyzed. Statistical hypothesis tests (sign-tests) confirmed that the Portuguese adult patient population anatomy deviates greatly from that of the reference anthropometric phantoms most commonly used in internal dosimetry, at least where age, weight and height are concerned. This supports recent approaches in Internal Radiation Dosimetry, which challenge the “Reference Man paradigm”, that is, the application of reference computational phantoms to the overall population [1]. New anthropomorphic models of the human body, representing Portuguese adult patients who undergo PET/CT examinations, will be created by combining Monte Carlo simulation of the radiation transport and image quantification techniques. These models will facilitate an accurate estimation of internal radiation doses.
{"title":"Population-based dosimetry in nuclear medicine and pet: Development of Portuguese female and male anthropomorphic models","authors":"A. Nunes, M. Patrício, F. Alves","doi":"10.1109/ENBENG.2015.7088821","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088821","url":null,"abstract":"Summary form only given. Internal organ dose estimates have always depended on standard reference models that mimic the interior and exterior anatomical features of the human body. These models are based on 20-30 year-old and healthy average European and North American populations, their organ masses and body weights and heights corresponding to the 50th percentile data [1]. However, if an individual patient deviates greatly from the reference anatomy, the use of a standard phantom can hinder the precision of the dose assessment being performed. Published anthropometric studies [2] suggest that the Portuguese population deviates from the parameters defined for the reference dosimetric models [3]. The general aim of the present research is to develop and validate two new anthropomorphic models of the human body (one male and one female), that specifically represent Portuguese adult patients who undergo PET/CT examinations. A secondary goal of this project is to profile the Portuguese patients undergoing PET/CT examinations, in respect to their age and internal and external anatomical features. In order to achieve this goal, anthropometric patient data regarding 18F-FDG PET/CT examinations performed at the Institute of Nuclear Sciences Applied to Health (ICNAS) were collected and analyzed. Statistical hypothesis tests (sign-tests) confirmed that the Portuguese adult patient population anatomy deviates greatly from that of the reference anthropometric phantoms most commonly used in internal dosimetry, at least where age, weight and height are concerned. This supports recent approaches in Internal Radiation Dosimetry, which challenge the “Reference Man paradigm”, that is, the application of reference computational phantoms to the overall population [1]. New anthropomorphic models of the human body, representing Portuguese adult patients who undergo PET/CT examinations, will be created by combining Monte Carlo simulation of the radiation transport and image quantification techniques. These models will facilitate an accurate estimation of internal radiation doses.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123961660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-20DOI: 10.1109/ENBENG.2015.7088876
P. Sampaio, C. Calado
Infrared spectroscopy, either in the near and mid (NIR/MIR) region of the spectra, has gained great acceptance in the industry for bioprocess monitoring according to Process Analytical Technology, due to its rapid, economic, high sensitivity mode of application and versatility. Due to the relevance of cyprosin (mostly for dairy industry), and as NIR and MIR spectroscopy presents specific characteristics that ultimately may complement each other, in the present work these techniques were compared to monitor and characterize by in situ and by at-line high-throughput analysis, respectively, recombinant cyprosin production by Saccharomyces cerevisiae. Partial least-square regression models, relating NIR and MIR-spectral features with biomass, cyprosin activity, specific activity, glucose, galactose, ethanol and acetate concentration were developed, all presenting, in general, high regression coefficients and low prediction errors. In the case of biomass and glucose slight better models were achieved by in situ NIR spectroscopic analysis, while for cyprosin activity and specific activity slight better models were achieved by at-line MIR spectroscopic analysis. Therefore both techniques enabled to monitor the highly dynamic cyprosin production bioprocess, promoting by this way more efficient platforms for the bioprocess optimization and control.
{"title":"Comparative analysis of near and mid-infrared spectroscopy to monitor recombinant cyprosin production","authors":"P. Sampaio, C. Calado","doi":"10.1109/ENBENG.2015.7088876","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088876","url":null,"abstract":"Infrared spectroscopy, either in the near and mid (NIR/MIR) region of the spectra, has gained great acceptance in the industry for bioprocess monitoring according to Process Analytical Technology, due to its rapid, economic, high sensitivity mode of application and versatility. Due to the relevance of cyprosin (mostly for dairy industry), and as NIR and MIR spectroscopy presents specific characteristics that ultimately may complement each other, in the present work these techniques were compared to monitor and characterize by in situ and by at-line high-throughput analysis, respectively, recombinant cyprosin production by Saccharomyces cerevisiae. Partial least-square regression models, relating NIR and MIR-spectral features with biomass, cyprosin activity, specific activity, glucose, galactose, ethanol and acetate concentration were developed, all presenting, in general, high regression coefficients and low prediction errors. In the case of biomass and glucose slight better models were achieved by in situ NIR spectroscopic analysis, while for cyprosin activity and specific activity slight better models were achieved by at-line MIR spectroscopic analysis. Therefore both techniques enabled to monitor the highly dynamic cyprosin production bioprocess, promoting by this way more efficient platforms for the bioprocess optimization and control.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123402090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-20DOI: 10.1109/ENBENG.2015.7088816
Tiago Branco, M. Patrício, F. Caramelo, M. Botelho
Summary form only given. Chromosomes are long molecules that naturally vibrate in different modes and are subject to random perturbations of the medium. Inducing vibration at the resonance frequency may be sufficient to cause the inactivation of the molecule by breaking chemical bonds. In this study we create a computational model of chromosomes and analyse the corresponding resonance frequencies. A simplified geometry is proposed to mimic chromosome arms. Each is represented by considering an eccentric cone. Running the simulations on a numerical package, the natural frequency was found for various chromosomes, in two modes of vibrations. Results show that each chromosome type presents different resonance frequencies in a range from 1.2 kHz up to 105 kHz. Changing mass and length of chromosome arm in a significant manner will produce a change in resonant frequency, as illustrated in the following graphics. This behavior may be use to derive new therapy forms targeting the destruction of mutated chromosomes.
{"title":"Mechanical resonance in human chromosomes","authors":"Tiago Branco, M. Patrício, F. Caramelo, M. Botelho","doi":"10.1109/ENBENG.2015.7088816","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088816","url":null,"abstract":"Summary form only given. Chromosomes are long molecules that naturally vibrate in different modes and are subject to random perturbations of the medium. Inducing vibration at the resonance frequency may be sufficient to cause the inactivation of the molecule by breaking chemical bonds. In this study we create a computational model of chromosomes and analyse the corresponding resonance frequencies. A simplified geometry is proposed to mimic chromosome arms. Each is represented by considering an eccentric cone. Running the simulations on a numerical package, the natural frequency was found for various chromosomes, in two modes of vibrations. Results show that each chromosome type presents different resonance frequencies in a range from 1.2 kHz up to 105 kHz. Changing mass and length of chromosome arm in a significant manner will produce a change in resonant frequency, as illustrated in the following graphics. This behavior may be use to derive new therapy forms targeting the destruction of mutated chromosomes.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116177254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-20DOI: 10.1109/ENBENG.2015.7088835
M. J. Jacinto, A. Azevedo, M. Aires-Barros, Marco Archinti, P. Marzábal
The N-terminal proline-rich domain (Zera®) of the maize storage protein γ-zein is a self-assembling domain produced and patented by EraBiotech, which can be fused with proteins of interest. Aqueous two-phase system (ATPS) is a biocompatible method for protein purification, without denaturation or loss of biological activity due to the high water content, low interfacial tension and stabilizing effect of the polymers. This work aims at developing and optimizing a scalable process for the extraction of Zera® fusion model proteins, Zera®, Zera®-alpha amylase and Zera®-lipase produced in Bacillus brevis to predict the partition of high-value recombinant proteins, as Zera®-Prostatic Acid Phosphatase (PAP), in PEG-phosphate ATPS. The influence of Polyethylene Glycol (PEG) molecular weight (MW), tie line Length (TLL), pH, sample load and neutral salt addition were evaluated and optimized for each recombinant proteins. Based on the partition results and the specific proteins characteristics (hydrophobicity and MW), a system with low TLL, PEG MW between 6 000 and 8 000, pH between 8-9 and loading percentage between 20 and 30% should probably be a good system for Zera®-PAP selective extraction.
{"title":"Extraction of Zera® fusion proteins in aqueous two-phase systems","authors":"M. J. Jacinto, A. Azevedo, M. Aires-Barros, Marco Archinti, P. Marzábal","doi":"10.1109/ENBENG.2015.7088835","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088835","url":null,"abstract":"The N-terminal proline-rich domain (Zera®) of the maize storage protein γ-zein is a self-assembling domain produced and patented by EraBiotech, which can be fused with proteins of interest. Aqueous two-phase system (ATPS) is a biocompatible method for protein purification, without denaturation or loss of biological activity due to the high water content, low interfacial tension and stabilizing effect of the polymers. This work aims at developing and optimizing a scalable process for the extraction of Zera® fusion model proteins, Zera®, Zera®-alpha amylase and Zera®-lipase produced in Bacillus brevis to predict the partition of high-value recombinant proteins, as Zera®-Prostatic Acid Phosphatase (PAP), in PEG-phosphate ATPS. The influence of Polyethylene Glycol (PEG) molecular weight (MW), tie line Length (TLL), pH, sample load and neutral salt addition were evaluated and optimized for each recombinant proteins. Based on the partition results and the specific proteins characteristics (hydrophobicity and MW), a system with low TLL, PEG MW between 6 000 and 8 000, pH between 8-9 and loading percentage between 20 and 30% should probably be a good system for Zera®-PAP selective extraction.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"2017 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114801426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-20DOI: 10.1109/ENBENG.2015.7088890
Ivo M. da Silva, J. Claro, A. Castro
Degenerative disc disease is the most common cause of low back pain, affecting 70-85% of the general population at some time in life. Considering this fact, it is essential to characterize the behavior of the intervertebral disc and its degeneration mechanisms. To study this problem, numerical modeling presents itself as an advantageous approach, being extensively used by researchers to understand the human spine complex. A lumbar partial motion segment model and respective finite element formulation are briefly described. The model's geometric sensitivity is analyzed by varying its wedge angle and average height, and simulating its biomechanical behavior under different incremental loads, using a homemade finite element solver. The results prove that both wedge angle and average height variations have significant influence in the intervertebral discs' behavior under loading.
{"title":"Geometric sensitivity analysis of a lumbar motion segment FE model","authors":"Ivo M. da Silva, J. Claro, A. Castro","doi":"10.1109/ENBENG.2015.7088890","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088890","url":null,"abstract":"Degenerative disc disease is the most common cause of low back pain, affecting 70-85% of the general population at some time in life. Considering this fact, it is essential to characterize the behavior of the intervertebral disc and its degeneration mechanisms. To study this problem, numerical modeling presents itself as an advantageous approach, being extensively used by researchers to understand the human spine complex. A lumbar partial motion segment model and respective finite element formulation are briefly described. The model's geometric sensitivity is analyzed by varying its wedge angle and average height, and simulating its biomechanical behavior under different incremental loads, using a homemade finite element solver. The results prove that both wedge angle and average height variations have significant influence in the intervertebral discs' behavior under loading.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121434988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-20DOI: 10.1109/ENBENG.2015.7088823
M. Cesário, Rodrigo S. Raposo, M. de Almeida, B. Ferreira, F. van Keulen, M. D. da Fonseca
Polyhydroxyalkanoates (PHAs) are biodegradable and thus environmentally friendly thermoplastics that are synthesized by various microbial strains as intracellular storage materials. These polyesters present a broad range of properties varying from very crystalline to more elastomeric polymers and find applications from agriculture to medicine. Despite their versatility, they are still not competitive due to the high production costs, of which the C-source accounts for circa 30%. To decrease raw materials costs, lignocellulosic agro-industrial residues rich in cellulose and hemicelluloses can be used as the C-source after being processed to yield simple sugars. Wheat straw lignocellulosic hydrolysates (LCH) were prepared (biorefinery.de GmbH) by pre-treating this residual biomass using the AFEX process followed by enzymatic hydrolysis. A hydrolysate rich in glucose and xylose and with low titres of inhibitory compounds is produced that can be used as carbon source for PHA production. Burkholderia sacchari DSM 17165 was selected for its ability to use both hexoses and pentoses. Polymer production was optimized in fed-batch cultivations in stirred-tank reactors (STR). Polymer concentration, volumetric productivity and polymer cell content of respectively 84 g/L, 1.6 g L-1h-1 and 68 % (w/w) were attained [1]. Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB-co-4HB) copolymers exhibit attractive thermal and mechanical properties due to the 4HB monomer. Synthesis of this monomer was achieved upon the addition of gamma-butyrolactone (GBL) as co-substrate to fed-batch cultures. Using a DOstat feeding strategy for LCH and a continuous addition of GBL, the maximum attained P(3HB-co-4HB) productivity and 4HB molar % were 0.5 g/(L.h) and 5.0 molar %, respectively [2]. Extraction of P(3HB) from the cells usually involves the use of halogenated solvents to attain high recovery yields and purities. However, the use of these solvents causes health and environmental hazards. To lessen this drawback green solvents were tested and high recovery yields and purities were achieved. Lignocellulosic agricultural residues can thus be ugraded with high yields and productivities to value-added products using the biorefinery concept.
聚羟基烷酸酯(PHAs)是一种可生物降解的环境友好型热塑性塑料，由各种微生物菌株合成，作为细胞内储存材料。这些聚酯具有广泛的性质，从非常结晶到更有弹性的聚合物，从农业到医学都有应用。尽管它们用途广泛，但由于生产成本高，它们仍然没有竞争力，其中c源约占30%。为了降低原材料成本，富含纤维素和半纤维素的木质纤维素农业工业残留物在加工成单糖后可以用作c源。采用AFEX工艺预处理剩余生物质，然后进行酶解，制备麦秸木质纤维素水解物(LCH) (biorefinery.de GmbH)。产生一种富含葡萄糖和木糖的水解产物，并具有低滴度的抑制化合物，可作为PHA生产的碳源。选择糖化伯克霍尔德菌DSM 17165是因为它能同时利用己糖和戊糖。在搅拌槽反应器(STR)加料间歇培养中优化了聚合物的生产。聚合物浓度为84 g/L，体积产率为1.6 g L-1h-1，聚合物细胞含量为68% (w/w)[1]。聚(3-羟基丁酸酯-co-4-羟基丁酸酯)(P3HB-co-4HB)共聚物由于含有4HB单体而表现出诱人的热性能和机械性能。该单体的合成是通过添加-丁内酯(GBL)作为共底物进行补料分批培养而实现的。采用DOstat加料策略和连续添加GBL，获得的最大P(3HB-co-4HB)产率和4HB摩尔%分别为0.5 g/(L.h)和5.0摩尔%[2]。从细胞中提取P(3HB)通常需要使用卤化溶剂，以获得较高的回收率和纯度。然而，使用这些溶剂会对健康和环境造成危害。为了减少这一缺点，对绿色溶剂进行了测试，获得了较高的回收率和纯度。因此，使用生物炼制概念，木质纤维素农业残留物可以以高产量和高生产率升级为增值产品。
{"title":"Upgrading wheat straw to HOMO and co-polyhydroxyalkanoates","authors":"M. Cesário, Rodrigo S. Raposo, M. de Almeida, B. Ferreira, F. van Keulen, M. D. da Fonseca","doi":"10.1109/ENBENG.2015.7088823","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088823","url":null,"abstract":"Polyhydroxyalkanoates (PHAs) are biodegradable and thus environmentally friendly thermoplastics that are synthesized by various microbial strains as intracellular storage materials. These polyesters present a broad range of properties varying from very crystalline to more elastomeric polymers and find applications from agriculture to medicine. Despite their versatility, they are still not competitive due to the high production costs, of which the C-source accounts for circa 30%. To decrease raw materials costs, lignocellulosic agro-industrial residues rich in cellulose and hemicelluloses can be used as the C-source after being processed to yield simple sugars. Wheat straw lignocellulosic hydrolysates (LCH) were prepared (biorefinery.de GmbH) by pre-treating this residual biomass using the AFEX process followed by enzymatic hydrolysis. A hydrolysate rich in glucose and xylose and with low titres of inhibitory compounds is produced that can be used as carbon source for PHA production. Burkholderia sacchari DSM 17165 was selected for its ability to use both hexoses and pentoses. Polymer production was optimized in fed-batch cultivations in stirred-tank reactors (STR). Polymer concentration, volumetric productivity and polymer cell content of respectively 84 g/L, 1.6 g L-1h-1 and 68 % (w/w) were attained [1]. Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB-co-4HB) copolymers exhibit attractive thermal and mechanical properties due to the 4HB monomer. Synthesis of this monomer was achieved upon the addition of gamma-butyrolactone (GBL) as co-substrate to fed-batch cultures. Using a DOstat feeding strategy for LCH and a continuous addition of GBL, the maximum attained P(3HB-co-4HB) productivity and 4HB molar % were 0.5 g/(L.h) and 5.0 molar %, respectively [2]. Extraction of P(3HB) from the cells usually involves the use of halogenated solvents to attain high recovery yields and purities. However, the use of these solvents causes health and environmental hazards. To lessen this drawback green solvents were tested and high recovery yields and purities were achieved. Lignocellulosic agricultural residues can thus be ugraded with high yields and productivities to value-added products using the biorefinery concept.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125536573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-04-20DOI: 10.1109/ENBENG.2015.7088803
D. Bicho, C. Caramlo-Nunes, B. F. Santos, A. Sousa, F. Sousa, J. Queiroz, C. Tomaz
In recent years, researchers have made several efforts to fight highly contagious respiratory disease caused by influenza virus. One of the best options for reducing the impact of this virus infection is DNA vaccination, therefore it is necessary a large quantity of highly pure plasmid DNA (pDNA) [1, 2]. Thus, in this work it is proposed the production and purification of pDNA expressing influenza virus hemaglutinin protein. For the purification strategy, monoliths are chosen because of their high binding capacity and the excellent mass transfer properties. Agmatine was the ligand of choice, once this amino acid derivative showed to be successful not only in the purification of sc pDNA isoforms but also from complex lysates. The results showed that agmatine is a multifaceted ligand to purify the sc pDNA influenza vaccine under the requirements of the regulatory agencies. In vitro experiments revealed that sc pDNA was able to transfect fibroblast cells and to produce hemaglutinin protein, as proved by immunochemistry analysis with mouse monoclonal anti HA H5N1 IgG primary antibody. The effect of plasmid transfection on cell viability was over 90% as demonstrated with activity of lactate dehydrogenase resazurin assays. In conclusion, our collective approach provides a valuable choice for the efficient isolation of sc pDNA hemaglutinin vaccine which can in near future prevent influenza infection.
{"title":"Amino acid derivatized monoliths for purification of a DNA vaccine against influenza","authors":"D. Bicho, C. Caramlo-Nunes, B. F. Santos, A. Sousa, F. Sousa, J. Queiroz, C. Tomaz","doi":"10.1109/ENBENG.2015.7088803","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088803","url":null,"abstract":"In recent years, researchers have made several efforts to fight highly contagious respiratory disease caused by influenza virus. One of the best options for reducing the impact of this virus infection is DNA vaccination, therefore it is necessary a large quantity of highly pure plasmid DNA (pDNA) [1, 2]. Thus, in this work it is proposed the production and purification of pDNA expressing influenza virus hemaglutinin protein. For the purification strategy, monoliths are chosen because of their high binding capacity and the excellent mass transfer properties. Agmatine was the ligand of choice, once this amino acid derivative showed to be successful not only in the purification of sc pDNA isoforms but also from complex lysates. The results showed that agmatine is a multifaceted ligand to purify the sc pDNA influenza vaccine under the requirements of the regulatory agencies. In vitro experiments revealed that sc pDNA was able to transfect fibroblast cells and to produce hemaglutinin protein, as proved by immunochemistry analysis with mouse monoclonal anti HA H5N1 IgG primary antibody. The effect of plasmid transfection on cell viability was over 90% as demonstrated with activity of lactate dehydrogenase resazurin assays. In conclusion, our collective approach provides a valuable choice for the efficient isolation of sc pDNA hemaglutinin vaccine which can in near future prevent influenza infection.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120988481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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