scholarly journals Uji Stabilitas pH dari Daun Mangga Hasil Ekstraksi Dengan Menggunakan Metode Spektrofotometer

METANA ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 13
Author(s):  
Kartika Dian Elliana ◽  
R.T.D. Wisnu Broto
Keyword(s):  
Isopropyl Alcohol ◽  
Stability Result ◽  
Extraction Process ◽  
Ph Stability ◽  
Decisive Factor ◽  
Leaf Chlorophyll ◽  
Mango Leaves ◽  
The Stability ◽  
Mixed Component ◽  
Selection Of

Ekstraksi merupakan proses pemisahan dan isolasi zat dari suatu zat dengan penambahan pelarut tertentu untuk mengeluarkan komponen campuran dari zat padat atau zat cair. Pada penelitian ini dilakukan ekstraksi klorofilid dari daun mangga untuk mengetahui stabilitas reduksi klorofil hasil ekstraksi berupa ekstrak dan rafinat. Ekstraksi klorofilid dilakukan dengan alat ekstraktor berpengaduk yaitu dengan memotong daun mangga 1 cm kemudian di ekstraksi dengan pelarut Aquadest 25%:75% Isopropil Alkohol.  Pemilihan pelarut merupakan faktor yang menentukan dalam proses ekstraksi. Hal-hal yang perlu diperhatikan dalam pemilihan pelarut adalah selektivitas, sifat pelarut, kemampuan untuk mengekstraksi, tidak bersifat racun, mudah diuapkan dan harganya relatif murah. Karakteristik ekstrak klorofilid menggunakan spektrofotometer untuk mengetahui absorbansi klorofil optimum dalam suatu variabel ekstrak dan rafinat serta uji pH untuk mengetahui stabilitas pH yang baik untuk mereduksi klorofil daun mangga. Hasil absorbansi klorofil optimum pada suhu 60OC dan waktu 70 menit pada ekstrak dan hasil stabilitas pH untuk mereduksi klorofil didapatkan pada pH 9 asam serta pH 2 basa.Extraction is the process of separating and isolating substances from a substance by adding a particular solvent to remove a mixed component of a solid or a liquid. In this study, extraction of chlorophyllid from mango leaves to determine the stability of chlorophyll reduction in the extract and raffinate. Extraction of chlorophyllid was done by stirring extractor that is by cutting mango leaves 1 cm then in extraction with Aquadest solvent 25%: 75% Isopropyl Alcohol. Selection of solvents is a decisive factor in the extraction process. Things to note in the selection of solvents are the selectivity, the properties of the solvent, the ability to extract, not toxic, easily evaporated and the price is relatively cheap. Characteristics of chlorophyll extract using spectrophotometer to determine the absorbance of optimum chlorophyll in an extract and raffinate variables and pH test to find out good pH stability to reduce mango leaf chlorophyll. The optimum chlorophyll absorbance results at 60OC and 70 minutes on the extract and the pH stability result to reduce chlorophyll was found at pH 9 acid and pH 2 base.

Global stability result for parabolic Cauchy problems

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Mourad Choulli ◽  
Masahiro Yamamoto
Keyword(s):  
New York ◽  
Partial Differential Equations ◽  
Global Stability ◽  
Classical Problem ◽  
Stability Result ◽  
Cauchy Problems ◽  
Smooth Solutions ◽  
Linear Partial Differential Equations ◽  
Ill Posed ◽  
The Stability

AbstractUniqueness of parabolic Cauchy problems is nowadays a classical problem and since Hadamard [Lectures on Cauchy’s Problem in Linear Partial Differential Equations, Dover, New York, 1953], these kind of problems are known to be ill-posed and even severely ill-posed. Until now, there are only few partial results concerning the quantification of the stability of parabolic Cauchy problems. We bring in the present work an answer to this issue for smooth solutions under the minimal condition that the domain is Lipschitz.

scholarly journals Spatio-temporal selection of reference genes in the two congeneric species of Glycyrrhiza

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuping Li ◽  
Xiaoju Liang ◽  
Xuguo Zhou ◽  
Yu An ◽  
Ming Li ◽  
...  
Keyword(s):  
Gene Expression ◽  
Developmental Stage ◽  
Reference Genes ◽  
Developmental Stages ◽  
Individual Factors ◽  
Congeneric Species ◽  
Spatio Temporal ◽  
The Stability ◽  
Different Tissues ◽  
Selection Of

AbstractGlycyrrhiza, a genus of perennial medicinal herbs, has been traditionally used to treat human diseases, including respiratory disorders. Functional analysis of genes involved in the synthesis, accumulation, and degradation of bioactive compounds in these medicinal plants requires accurate measurement of their expression profiles. Reverse transcription quantitative real-time PCR (RT-qPCR) is a primary tool, which requires stably expressed reference genes to serve as the internal references to normalize the target gene expression. In this study, the stability of 14 candidate reference genes from the two congeneric species G. uralensis and G. inflata, including ACT, CAC, CYP, DNAJ, DREB, EF1, RAN, TIF1, TUB, UBC2, ABCC2, COPS3, CS, R3HDM2, were evaluated across different tissues and throughout various developmental stages. More importantly, we investigated the impact of interactions between tissue and developmental stage on the performance of candidate reference genes. Four algorithms, including geNorm, NormFinder, BestKeeper, and Delta Ct, were used to analyze the expression stability and RefFinder, a comprehensive software, provided the final recommendation. Based on previous research and our preliminary data, we hypothesized that internal references for spatio-temporal gene expression are different from the reference genes suited for individual factors. In G. uralensis, the top three most stable reference genes across different tissues were R3HDM2, CAC and TUB, while CAC, CYP and ABCC2 were most suited for different developmental stages. CAC is the only candidate recommended for both biotic factors, which is reflected in the stability ranking for the spatio (tissue)-temporal (developmental stage) interactions (CAC, R3HDM2 and DNAJ). Similarly, in G. inflata, COPS3, R3HDM2 and DREB were selected for tissues, while RAN, COPS3 and CS were recommended for developmental stages. For the tissue-developmental stage interactions, COPS3, DREB and ABCC2 were the most suited reference genes. In both species, only one of the top three candidates was shared between the individual factors and their interactions, specifically, CAC in G. uralensis and COPS3 in G. inflata, which supports our overarching hypothesis. In summary, spatio-temporal selection of reference genes not only lays the foundation for functional genomics research in Glycyrrhiza, but also facilitates these traditional medicinal herbs to reach/maximize their pharmaceutical potential.

scholarly journals Longevity of Raw and Lyophilized Crude Urease Extracts

2021 ◽  
Vol 2 (2) ◽  
pp. 325-334
Author(s):  
Neda Javadi ◽  
Hamed Khodadadi Tirkolaei ◽  
Nasser Hamdan ◽  
Edward Kavazanjian
Keyword(s):  
Crude Extract ◽  
Room Temperature ◽  
Low Cost ◽  
Extraction Process ◽  
Crude Extracts ◽  
Simple Extraction ◽  
Commercial Applications ◽  
Stable Source ◽  
The Stability ◽  
The Cost

The stability (longevity of activity) of three crude urease extracts was evaluated in a laboratory study as part of an effort to reduce the cost of urease for applications that do not require high purity enzyme. A low-cost, stable source of urease will greatly facilitate engineering applications of urease such as biocementation of soil. Inexpensive crude extracts of urease have been shown to be effective at hydrolyzing urea for carbonate precipitation. However, some studies have suggested that the activity of a crude extract may decrease with time, limiting the potential for its mass production for commercial applications. The stability of crude urease extracts shown to be effective for biocementation was studied. The crude extracts were obtained from jack beans via a simple extraction process, stored at room temperature and at 4 ℃, and periodically tested to evaluate their stability. To facilitate storage and transportation of the extracted enzyme, the longevity of the enzyme following freeze drying (lyophilization) to reduce the crude extract to a powder and subsequent re-hydration into an aqueous solution was evaluated. In an attempt to improve the shelf life of the lyophilized extract, dextran and sucrose were added during lyophilization. The stability of purified commercial urease following rehydration was also investigated. Results of the laboratory tests showed that the lyophilized crude extract maintained its activity during storage more effectively than either the crude extract solution or the rehydrated commercial urease. While incorporating 2% dextran (w/v) prior to lyophilization of the crude extract increased the overall enzymatic activity, it did not enhance the stability of the urease during storage.

Stabilization of networked switched affine systems with event-triggered strategy

2021 ◽  
pp. 014233122110213
Author(s):  
Dandan Li ◽  
Zhiqiang Zuo ◽  
Yijing Wang
Keyword(s):  
Affine Systems ◽  
Switching Law ◽  
Event Time ◽  
Sliding Motion ◽  
State Dependent ◽  
Event Triggering ◽  
Stability Issue ◽  
The Stability ◽  
Event Based ◽  
Selection Of

Using an event-based switching law, we address the stability issue for continuous-time switched affine systems in the network environment. The state-dependent switching law in terms of the region function is firstly developed. We combine the region function with the event-triggering mechanism to construct the switching law. This can provide more candidates for the selection of the next activated subsystem at each switching instant. As a result, it is possible for us to activate the appropriate subsystem to avoid the sliding motion. The Zeno behavior for the switched affine system can be naturally ruled out by guaranteeing a positive minimum inter-event time between two consecutive executions of the event-triggering threshold. Finally, two numerical examples are given to demonstrate the effectiveness of the proposed method.

L 1 and L ∞ stability of transition densities of perturbed diffusions

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ilya Bitter ◽  
Valentin Konakov
Keyword(s):  
Linear Growth ◽  
Stability Result ◽  
Regularity Conditions ◽  
Initial Condition ◽  
Weak Regularity ◽  
Transition Densities ◽  
The Stability ◽  
Drift Terms

Abstract In this paper, we derive a stability result for L 1 {L_{1}} and L ∞ {L_{\infty}} perturbations of diffusions under weak regularity conditions on the coefficients. In particular, the drift terms we consider can be unbounded with at most linear growth, and the estimates reflect the transport of the initial condition by the unbounded drift through the corresponding flow. Our approach is based on the study of the distance in L 1 {L_{1}} - L 1 {L_{1}} metric between the transition densities of a given diffusion and the perturbed one using the McKean–Singer parametrix expansion. In the second part, we generalize the well-known result on the stability of diffusions with bounded coefficients to the case of at most linearly growing drift.

The Weight of Fear of Violence in Household Budgets

2021 ◽  
pp. 073401682110383
Author(s):  
Bruno Truzzi ◽  
Marcelo Justus ◽  
Henrique C. Kawamura ◽  
Thomas V. Conti
Keyword(s):  
Instrumental Variables ◽  
Regularization Method ◽  
Household Level ◽  
Household Spending ◽  
Goods And Services ◽  
Level Ii ◽  
The Stability ◽  
The Relationship ◽  
Selection Of

This article investigates the relationship between the perception of violence and the spending on security goods and services in households. Individual microdata from a random national survey on family budget carried out in Brazil in 2008-2009 were used for modeling the household spending using two instrumental variables. The stability of results was checked by applying the Lasso-Gaussian regularization method in the selection of the statistically significant variables. Positive relationships were found between household spending on security goods and services and (i) the fear of insecurity at the household level, (ii) the neighbors’ spending on security, and (iii) the registered criminality, but no evidence was found on the relationship between the role of police on household spending on security goods and services.

scholarly journals SURVEYING IN THE STUDIES OF THE STABILITY OF EARTHY CONSTRUCTIONS, FOCUS ON SELECTED HISTORICAL MOUNDS IN KRAKOW (POLAND)

2016 ◽  
Vol 22 (2) ◽  
pp. 324-341
Author(s):  
Rafał Gawałkiewicz ◽  
Anna Szafarczyk
Keyword(s):  
Landslide Monitoring ◽  
Measurement Technology ◽  
Degree Of Deformation ◽  
Soil Creep ◽  
Measurement Series ◽  
Efficient Protection ◽  
The Stability ◽  
The Impact ◽  
Measurement Base ◽  
Selection Of

Mounds, as anthropogenic constructions of a very delicate structure, are subdued to constant changes, which, due to the impact of external factors (prolonged precipitation, tremors) are subdued to deformations in the form of mass movements. These phenomena usually have the character of mild soil creep in time and sometimes, as a result of rapid loss of stability, they are seriously damaged by landslide. This phenomenon causes temporary exclusion of the object from use. In the framework of the protection of these objects, the maintenance was carried out within the preventive measures referring to the construction and surveying monitoring of the geometry changes in time, as a result of phenomena taking place in the ground medium under the influence of environmental factors causing strains. The process of the deformation of mounds is similar to the characteristic, according to the Terzagie's theory. The application of surveying technologies of high precision allows the monitoring of changes in their geometry in time. The properly defined study area and the proper selection of measurement technology in the aspect of the accuracy of the prediction of changes, can efficiently help in defining the scale of deformations in the decisive process referring to the way of efficient protection of barrows. The article presents the results of point monitoring carried out with surveying technologies within 11 measurement series carried out on the selected measurement base of the Wanda Mound. The use of measurement technologies of integrated and specialist software, allows complex assessment of the degree of deformation and the trends of these changes in time, as well as identifying anomaly zones in the framework of the landslide monitoring.

Stability of a tokamak plasma with diffuse toroidal rotation

2020 ◽  
Vol 86 (5) ◽  
Author(s):  
O. E. López ◽  
L. Guazzotto
Keyword(s):  
Shooting Method ◽  
Tokamak Plasma ◽  
Solution Technique ◽  
Large Aspect Ratio ◽  
Internal Resonances ◽  
Flow Shear ◽  
Magnetic Shear ◽  
The Stability ◽  
External Kink ◽  
Selection Of

The present work considers the stability of a high- $\beta$ , large aspect ratio, circular plasma with diffuse profiles for the safety factor and the angular toroidal frequency (López & Guazzotto, Phys. Plasmas, vol. 24, 032501). An application of the Frieman–Rotenberg formalism results in a system of scalar eigenmode equations whose coupling is retained at the plasma–vacuum transition but is disregarded across the plasma column, which is a standard practice. The solution technique consists of a multidimensional shooting method for the poloidal harmonics; robust initial guesses are constructed by solving the dispersion relation in the static scenario with vanishing magnetic shear. Flow shear appears as a high- $\beta$ toroidal contribution, and we illustrate its destabilizing influence on $n=1$ external kink modes in the presence of ideal and resistive walls. Internal resonances are avoided by means of the selection of appropriate equilibrium parameters. The stabilizing influence of a finite positive average magnetic shear is also exemplified.

Extraction Process of Amaranthine Pigment Keeping the Water Wax Fuit Biological Active

2013 ◽  
Vol 295-298 ◽  
pp. 150-154
Author(s):  
Feng Jie Wang ◽  
Xin Qiao Dong ◽  
Xiao Liu
Keyword(s):  
Citric Acid ◽  
Extraction Method ◽  
Raw Materials ◽  
Extraction Process ◽  
Extraction Yield ◽  
Extraction Temperature ◽  
Natural Pigment ◽  
Pigment Extraction ◽  
Acid Aqueous Solution ◽  
The Stability

Development natural pigment retained a variety of nutrition composition is extremely research value.Water Wax Trees Fruit was as raw materials,citric acid aqueous solution was as extracting agent.Amaranthine pigment extraction method were studied on fully grasping the stability of the natural amaranthine pigment and no damage to the water wax fruit biological activity.The effect of extraction yield were studied on Water Wax Trees Fruit natural amaranthine pigment.The results show that the better extraction conditions are extraction temperature at 70 °C, extraction time for 3h,citric acid concentration1.0 % , the material/liquid ration(g/ml) 1:5.The extraction yield is 2.95%.Ultraviolet absorption maximum wavelength is 280 nm.

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