Optimization of Switching Time from Growth to Product Formation for Maximum Productivity of Recombinant Escherichia coli Fermentation

Patkar, Anant Y.,Shin, Pyong K.,Seo, Jin Ho 한국산업미생물학회 1990 한국미생물·생명공학회지 Vol.18 No.4

유전자 조작된 세포 발효공정의 생산수율을 최대화하기 위하여 세포의 성장속도와 제품 생성속도간의 상반관계를 고려하여야 한다. 유전자 조작된 E. coli 발효에 있어, 최적화 이론을 적용하여 두 속도의 가중치를 결정함으로써 생산수율의 최대화를 꾀하였다. 성장저해제의 농도는 비성장속도를 조절하고 결국 융합된 유전자의 발현속도를 조절하는 변수로 사용된다. 이런 system의 특성을 위하여 간단한 unstructured model을 사용하였다. 이론적 해석에 의하면, 최적조절곡선은 초기의 높은 세포성장속도에 이어서 낮은 성장속도와 더불어 높은 물질생성속도를 보이는 두 단계로 구성된다. 물질생성속도가 세포성장속도에 대해 서로 다른 의존도를 보이는 대표적인 두 가지 경우에 대해, 수식계산을 통해 세포성장에서 물질생성으로 전환시키는 시기를 결정하였다. 물질생성속도가 세포생장속도에 민감한 경우 최적화 조작을 시행했을 때 단순 회분식 발효에 비해 최종생산물 농도가 약 60% 증가함을 알 수 있었다. Maximization of productivity of recombinant cell fermentations requires consideration of the inverse relationship between the host cell growth rate and product formation rate. The problem of maximizing a weighted performance index was solved by using optimal control theory for recombinant E. coli fermentation. Concentration of a growth inhibitor was used as a control variable to manipulate the specific growth rate, and consequently the cloned-gene expression rate. Using a simple unstructured model to describe the main characteristics of this system, theoretical analysis showed that the optimal control profile results in an initial high growth rate phase followed bya low growth rate and high product formation rate phase. Numerical calculations were done to determine optimal switching times from the growth to the production stage for two representative cases corresponding to different dependency of the product formation rate on the growth rate. For the case when product formation rate is sensitive to the specific growth rate, the optimized operation yields about 60% increase in the final product concentration compared with a simple batch fermentation.

Optimization of Hydropower Plants Regarding Hydro-abrasive Erosion

Anant Kumar Rai,Arun Kumar,Thomas Staubli 한국유체기계학회 2019 International journal of fluid machinery and syste Vol.12 No.2

The hydro-abrasive erosion poses challenges for smooth and efficient operation of existing hydropower plants (HPPs) as well as planning for new HPPs. The loss in revenue is caused due to reduced generation on account of reduced efficiency, down time for repair and maintenance for restoring the machinery and other components. In this study, various optimization considerations required with respect to hydro-abrasive erosion at both the planning and the operation stage of a HPP are presented. The factors involved in each steps like unit sizing, selection and design of turbines, capacity of desanders, cut-off limits of sediment concentration for turbine switch-offs, preventive measures such as coatings etc. were discussed. Further, a case study of an operational HPP located in Indian Himalayas is presented where suspended sediments, hydro-abrasive erosion and reduction in efficiency were measured simultaneously. Available models were used with measured values to obtain various losses due to hydro-abrasive erosion. The cost of coating, a preventive measure, is compared with the losses in operating the uncoated turbine. A decision making criterion is also introduced.

A High Quality Steganographic Method Using Morphing

( Anant M Bagade ),( Sanjay N Talbar ) 한국정보처리학회 2014 Journal of information processing systems Vol.10 No.2

A new morphed steganographic algorithm is proposed in this paper. Image security is a challenging problem these days. Steganography is a method of hiding secret data in cover media. The Least Significant Bit is a standard Steganographic method that has some limitations. The limitations are less capacity to hide data, poor stego image quality, and imperceptibility. The proposed algorithm focuses on these limitations. The morphing concept is being used for image steganography to overcome these limitations. The PSNR and standard deviation are considered as a measure to improve stego image quality and morphed image selection, respectively. The stego keys are generated during the morphed steganographic embedding and extracting process. Stego keys are used to embed and extract the secret image. The experimental results, which are based on hiding capacity and PSNR, are presented in this paper. Our research contributes towards creating an improved steganographic method using image morphing. The experimental result indicates that the proposed algorithm achieves an increase in hiding capacity, stego image quality, and imperceptibility. The experimental results were compared with state of the art steganographic methods.

연구발표초록 ( 생물화공 ) : 유전자 재조작된 효모로부터 Invertase 생산을 위한 포도당 농도의 최적화

Anant Patkar,서진호 ( Jin Ho Seo ) 한국화학공학회 1990 춘계학술발표회 Vol.- No.-

Sediment monitoring for hydro-abrasive erosion

Anant Kr. Rai,Arun Kumar 한국유체기계학회 2017 International journal of fluid machinery and syste Vol.10 No.2

Sediment flow through hydropower components causes hydro-abrasive erosion resulting in loss of efficiency, interruptions in power production and downtime for repair/maintenance. Online instruments are required to measure/capture the variations in sediment parameters along with collecting samples manually to analyse in laboratory for verification. In this paper, various sediment parameters viz. size, concentration (TSS), shape and mineral composition relevant to hydro-abrasive erosion were measured and discussed with respect to a hydropower plant in Himalayan region, India. A multi-frequency acoustic instrument was installed at a desilting chamber to continuously monitor particle size distribution (PSD) and TSS entering the turbine during 27 May to 6 August 2015. The sediment parameters viz. TSS, size distribution, mineral composition and shape entering the turbine were also measured and analysed, using manual samples collected twice daily from hydropower plant, in laboratory with instruments based on laser diffraction, dynamic digital image processing, gravimetric method, conductivity, scanning electron microscope, X-ray diffraction and turbidity. The acoustic instrument was able to capture the variation in TSS; however, significant deviations were found between measured mean sediment sizes compared to values found in the laboratory. A good relation was found for turbidity (R<SUP>2</SUP> = 0.86) and laser diffraction (R<SUP>2</SUP> = 0.93) with TSS, which indicated that turbidimeter and laser diffraction instrument can be used for continuous monitoring of TSS at the plant. Total sediment load passed through penstock during study period was estimated to be 15,500 ton. This study shall be useful for researchers and hydropower managers in measuring/monitoring sediment for hydro-abrasive erosion study in hydropower plants.

Mechanical Properties of Alkali Activated Fly Ash Geopolymer Stabilized Expansive Clay

Anant Lal Murmu,Anamika Jain,Anjan Patel 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.9

It has always been a challenge for civil engineers to lay roads in the areas covered by expansive soil. The expansive soil undergoes extreme phase changes from being hard in hot summer to being slushy and without strength in monsoon season. Thus, the engineering properties of the expansive soil must be improved before laying the roads. This paper presents the results of experimental work carried out to improve the engineering properties of an expansive clay i.e. black cotton soil (BCS) by using fly ash geopolymer. Sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) solutions were mixed in different ratios (0.5, 1, 1.5, and 2) and used for synthesizing the geopolymer. The stabilized BCS samples were characterized in the laboratory for various properties viz., Atterberg’s limits, free swell ratio, and unconfined compressive strength. The untreated and treated BCS samples were also analyzed for their microstructural and morphological properties by using the SEM (scanning electron microscope) images and the XRD (X-ray diffractometer) and FTIR (Fourier-transform infrared spectroscopy) spectra. An increase in the unconfined compressive strength and reduction in free swell ratio as well as shrinkage limit was observed after stabilization with geopolymer. Results also indicate binding of soil particles and formation of dense microstructure resulting in higher strength and less swelling and shrinkage characteristics. Furthermore, the bender element test was used to indicate the improvement in stiffness of the geopolymer stabilized expansive soil in terms of shear wave velocity.

Early pharmacokinetic evaluation of anti-tubercular treatment as a good indicator of treatment success in pulmonary tuberculosis patients on a retreatment regimen

Mohan Anant,Bhatnagar Anuj,Gupta Tarang,Ujjalkumar Das,Kanswal Sunita,Velpandian Thirumurthy,Guleria Randeep,Singh Urvashi B. 한국약제학회 2022 Journal of Pharmaceutical Investigation Vol.52 No.4

Purpose Patients with pulmonary tuberculosis (PTB) who fail therapy or develop a relapse are initiated on a retreatment regimen. These patients are at high risk for adverse outcomes. This study aimed to assess the relationship between plasma levels of anti-tubercular drugs and therapy outcome in patients on retreatment. Methods Pharmacokinetics of retreatment regimen drugs [isoniazid (INH), rifampicin (RIF), pyrazinamide (PZA), ethambutol (EMB), and streptomycin (STM)] were compared between cured and not-cured patients using liquid chromatographytandem mass spectrometry (LC-MS/MS) in 134 patients with PTB on a retreatment regimen. Results Of 134 patients, 108 were cured, 17 developed multi-drug resistant TB (MDR-TB), and 9 remained smear-positive after completion of the retreatment (8 months). Two-hour plasma levels ( C2hr) at Day 0 were lower in ‘not cured’ subjects than ‘cured’ subjects and reflected the drug levels achieved later in the duration of retreatment. Notably, in the 26 ‘not cured’ subjects, C2hr plasma levels after the first dose at Day 0 were significantly low (INH: 0.86 vs. 2.94 mg/L, p ≤ 0.002, RIF: 0.56 vs. 2.55 mg/L, p ≤ 0.003, PZA: 1.85 vs. 26.58 mg/L, p ≤ 0.001 and EMB: 0.72 vs. 1.53 mg/L, p ≤ 0.010). Conclusion Therapeutic failure in patients with PTB on a retreatment regimen is associated with lower plasma drug levels. Therapeutic drug monitoring would prove useful for obtaining a favorable clinical outcome. C2hr levels on Day 0 reflected drug levels achieved later and could be a good predictor of patient outcome.

Sediment monitoring for hydro-abrasive erosion: A field study from Himalayas, India

Rai, Anant Kr.,Kumar, Arun Korean Society for Fluid machinery 2017 International journal of fluid machinery and syste Vol.10 No.2

Sediment flow through hydropower components causes hydro-abrasive erosion resulting in loss of efficiency, interruptions in power production and downtime for repair/maintenance. Online instruments are required to measure/capture the variations in sediment parameters along with collecting samples manually to analyse in laboratory for verification. In this paper, various sediment parameters viz. size, concentration (TSS), shape and mineral composition relevant to hydro-abrasive erosion were measured and discussed with respect to a hydropower plant in Himalayan region, India. A multi-frequency acoustic instrument was installed at a desilting chamber to continuously monitor particle size distribution (PSD) and TSS entering the turbine during 27 May to 6 August 2015. The sediment parameters viz. TSS, size distribution, mineral composition and shape entering the turbine were also measured and analysed, using manual samples collected twice daily from hydropower plant, in laboratory with instruments based on laser diffraction, dynamic digital image processing, gravimetric method, conductivity, scanning electron microscope, X-ray diffraction and turbidity. The acoustic instrument was able to capture the variation in TSS; however, significant deviations were found between measured mean sediment sizes compared to values found in the laboratory. A good relation was found for turbidity ($R^2=0.86$) and laser diffraction ($R^2=0.93$) with TSS, which indicated that turbidimeter and laser diffraction instrument can be used for continuous monitoring of TSS at the plant. Total sediment load passed through penstock during study period was estimated to be 15,500 ton. This study shall be useful for researchers and hydropower managers in measuring/monitoring sediment for hydro-abrasive erosion study in hydropower plants.

DEVELOPMENT OF A COMPUTER ALGORITHM BASED ON A CONJUGATE GRADIENT APPROACH FOR OPTIMIZATION OF FED - BATCH FERMENTATIONS

Patkar, Anant,Lee, Dong Hoon,SEO, JIN HO 한국화학공학회 1993 Korean Journal of Chemical Engineering Vol.10 No.3

The problem of optimization of fed-batch fermentations using the substrate feed rate as the control variable is singular in nature. Previous approaches, including the boundary condition iteration method and transformation to a nonsingular problem using a different control variable, do not work well for solving optimization of systems governed by more than four differential equations. The applicability of a first-order conjugate gradient algorithm for optimizing fed-batch fermentations was tested for systems of varing complexity. This approach does not need any variable transformation or a priori knowledge of the control arc sequence. Constraints on the feed rate are handled in a simple and direct manner. The algorithm worked very well for three, four, and five-dimensional singular systems. The correctness of the optimal profile was judged by observing the variation in the sign of the gradient of the Hamiltonian. The gradient was found to be zero during the singular period and had the appropriate sign on the boundary arcs. The optimization method based on conjugated gradient approach can be complementary to the boundary condition iteration method for determination of the exact optimum profile.

A High Quality Steganographic Method Using Morphing

Bagade, Anant M.,Talbar, Sanjay N. Korea Information Processing Society 2014 Journal of information processing systems Vol.10 No.2

A new morphed steganographic algorithm is proposed in this paper. Image security is a challenging problem these days. Steganography is a method of hiding secret data in cover media. The Least Significant Bit is a standard Steganographic method that has some limitations. The limitations are less capacity to hide data, poor stego image quality, and imperceptibility. The proposed algorithm focuses on these limitations. The morphing concept is being used for image steganography to overcome these limitations. The PSNR and standard deviation are considered as a measure to improve stego image quality and morphed image selection, respectively. The stego keys are generated during the morphed steganographic embedding and extracting process. Stego keys are used to embed and extract the secret image. The experimental results, which are based on hiding capacity and PSNR, are presented in this paper. Our research contributes towards creating an improved steganographic method using image morphing. The experimental result indicates that the proposed algorithm achieves an increase in hiding capacity, stego image quality, and imperceptibility. The experimental results were compared with state of the art steganographic methods.