Effects of Different Preservation Methods on Activity of Recombinant E. coli

[ Objective] To explore different preservation methods of recombinant E. coli and find out the optimal conditions for preservation. [ Method] The recombinant E. coli DH5cx transformed pcDNA.3 were respectively preserved at 4℃ and -70 ℃, and the activity was determined after dif- ferent time. [ Result] The number of living E. coll with high dilutions preserved at 4 ℃ was gradually increased within the first 7 d, peaked on Day 7, and then gradually decreased. The number of living E. coli, which were preserved in 8% glycerol at -70℃ when OD800 at 0.8, were significantly higher than that of other groups after different preservation time. [ Conclusion] The optimal storage time was 7 d for recombinant E. coli at 4 ℃. For preservation at -70 ℃, the bacteria should be in logarithmic growth phase and preserved in 8% glycerol.

A multi-criteria decision-making approach for comparing sample preservation and DNA extraction methods from swine feces

Molecular microbiological methods, such as competetive PCR, real-time PCR, denaturing gradient gel electrophoresis (DGGE) and large-scale parallel-pyrosequencing, require the extraction of sufficient quantity of high quality DNA from microbiologically and chemically complex matrices. Due to difficulties in the field to standardize/select the optimum DNA preservation-extraction methods in view of laboratories differences, this article attempts to present a straight-forward mathematical framework for comparing some of the most commonly used methods. To this end, as a case study, the problem of selecting an optimum sample preservation-DNA extraction strategy for obtaining total bacterial DNA from swine feces was considered. Two sample preservation methods (liquid nitrogen and RNAlater?) and seven extraction techniques were paired and compared under six quantitative DNA analysis criteria: yield of extraction, purity of extracted DNA (A260/280 and A 260/230 ratios), duration of extraction, degradation degree of DNA, and cost. From a practical point of view, it is unlikely that a single sample preservation-DNA extraction strategy can be optimum for all selected criteria. Hence, a systematic multi-criteria decision-making (MCDM) approach was used to compare the methods. As a result, the ZR Fecal DNA MiniPrepTM DNA extraction kit for samples preserved either with liquid nitrogen or RNAlater? were identified as potential optimum solutions for obtaining total bacterial DNA from swine feces. Considering the need for practicality for in situ applications, we would recommend liquid nitrogen as sample preservation method, along with the ZR Fecal DNA MiniPrepTM kit. Total bacterial DNA obtained by this strategy can be suitable for downstream PCR-based DNA analyses of swine feces.

Effects of Different Preservation Methods on Vitamin C and Nitrate Content in Vegetables

This paper studied and compared the effects of three preservation methods( normal temperature 20℃,fresh-keeping box cold storage 4℃,and fresh-keeping box + fresh-keeping film cold storage 4℃) on six kinds of vegetables. The results showed that the content of vitamin C in the six vegetables was higher in cold storage than in normal temperature storage; the nitrate content was lower in cold storage than in normal temperature storage. In both the normal temperature storage and cold storage,the vitamin C in vegetables declined with the increase of the storage time,while the nitrate content increased with the increase of the storage time. Thus,cold storage has better fresh-keeping effect for vegetables. In cold storage conditions,the vitamin C content was higher in vegetables packaged by fresh-keeping box,and the nitrate content was lower,followed by the fresh-keeping film + fresh-keeping box cold storage. In conclusion,the best preservation method for vegetable is fresh-keeping box cold storage.

Different Preservation Methods for Long Term Maintenance of <i>Haemophilus influenzae</i>

Haemophilus species are Gram-negative coccobacilli that require factor X and factor V for growth. Beyond this, it is a finicky bacterium to culture, and any modification of culture procedures greatly reduces isolation rates. Poor quality of laboratories in developing countries results in its poor isolation rates. This study was done with the objective of finding out the optimal cultural environment and media so that it could be maintained for a longer period in economical settings like ours which was done using H. influenzae ATCC 49,766. In this study, several culture media were tested as a means to preserve H. influenzae ATCC like TSB + glycerol + sheep blood, BHI broth, BHI broth + glycerol, BHI broth+ glycerol + sheep blood, Chocolate agar slant and satellitism plate. Three sets of respective media were inoculated with 18 - 24 hours growth of H. influenzae. They were incubated at 37?oC 48 hours in a candle extinction jar. The media were checked for growth by subculturing them on chocolate agar plates and identified by biochemical reactions. Each set was maintained at 2 oC - 8?oC, -20?oC and at room temperature and checked for the viability 24 hourly by subculturing them on chocolate agar. Results showed best growth of H. influenza on chocolate agar slants for 15 - 20 days, followed by BHI + glycerol + sheep blood broth and satellitism plate for 4 - 6 days followed by BHI broth for 2 - 4 days. There was no growth in TSB + glycerol + sheep blood broth and BHI + glycerol broth media. Present study showed similar results as done by NS Srikanth et al. 2003 with growth on chocolate agar & satellitism plate for 3 - 5 days but no growth in TSB + Glycerol + Sheep blood broth media. Chocolate agar slant is by far the most long term preserving media for H. influenzae. However, growth on BHI broth with various modifications is also showed a good preservation for 3 - 5 days, so with further experiments we can hope to maintain the organism in these media also.

Health Preservation Methods Of Tibetan Medicine

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Optimal Sample Preservation and Analysis of Cr(VI) in Drinking Water Samples by High Resolution Ion Chromatography Followed by Post Column Reaction and UV/Vis Detection

A recent study by the Environmental Working Group reported the detection of hexavalent chromium (Cr(VI)) in tap water at 31 out of 35 states investigated in the United States. Even though Cr(III) is an essential element for human diet, Cr(VI) is a potential carcinogen. Previous work has clearly identified a linear trend of increasing risk of lung cancer mortality with increasing cumulative exposure to water soluble Cr(VI). Regardless, Cr(VI) is still not regulated or monitored in drinking water in the U.S. There is an existing method (EPA 218.6) for the analysis of Cr(VI), however, this analytical method does not addresses detailed sample preservation techniques and optimization process to achieve lowest detection limit possible. In this study, five buffer solutions with pH of 9 and above were compared to determine the most suitable buffer to preserve Cr(VI) in drinking water samples for an extended period of time. Results showed that the five buffers responded very differently to Cr(VI)-fortified drinking water. The best preserving reagent was found to be Ammonium Hydroxide + Ammonium Sulfate (pH 9.2) and Sodium Carbonate + Sodium Bicarbonate+ Ammonium Sulfate (pH 9.7), whereas a buffer solution with Sodium Hydroxide + Sodium Carbonate (pH 11.5+) resulted in a poor chromatographic resolution. A controlled study with a fortified Cr(III) at 1 ppb was also conducted to ensure no false positive detection of Cr(VI) due to the potential oxidation of Cr(III) during sample storage. The optimal preserving reagent identified from this study was compatible with the existing EPA method 218.6 using ion chroma-tography followed by post column reaction, with a method quantitation limit of 0.020 ppb and matrix spike recovery of ± 10%.

Preservation Property and Decay Kinetic of Polyurethane Immobilized Nitrifying Bacteria Pellets

The preservation methods of polyurethane immobilized nitrifying bacteria pellets which had been enriched in laboratory were provided. Factors such as temperature, pH and light, which affect the nitrification activity of polyurethane immobilized pellets, were investigated. The result showed that dark, deionized water and low temperature is suitable for polyurethane immobilized nitrifying bacteria pellets’ long term preservation.

Integrated Use of Alternative Methods for Evaluating the Skin Sensitization Potencies of Five Frequently Used Preservatives in Cosmetics

In vitro skin sensitization testing methods based on the adverse outcome pathway(AOP)were used to evaluate the skin sensitization potencies of 5 commonly used preservatives.According to the“2 out of 3”principle of the integrated approaches to testing and assessment(IATA)the direct peptide reactivity assay(DPRA)and the human cell line activation test(h-CLAT)were used to detect the preservatives commonly used in cosmetics,including phenoxyethanol.methyl paraben,propyl paraben,imidazolidinyl urea and DMDM hydantoin.The DPRA and the h-CLA were carried out according to the OEC442C and 442E guidelines,respectively.The results show that.phenoxyethanol and methyl paraben are both negative in DPRA and h-CLAT while imidazolidinyl urea and DMDM hydantoin are both positive in these two tests.Propyl paraben has negative result in DPRA but positive result in h-CLAT.Therefore,imidazolidiny urea and DMDM hydantoin are sensitizers,while phenoxyethanol and methylparaben are non-sensitizers.Taken animal and human data into consideration,it is predicted that propyl paraben should be a non-sensitizer.The combination of DPRA and h-CLAT can make up for the limitations of using a single method,and it is suitable for the preliminary screening of cosmetic raw materials according to skin sensitization.

An Arbitrarily High Order and Asymptotic Preserving Kinetic Scheme in Compressible Fluid Dynamic

We present a class of arbitrarily high order fully explicit kinetic numerical methods in compressible fluid dynamics,both in time and space,which include the relaxation schemes by Jin and Xin.These methods can use the CFL number larger or equal to unity on regular Cartesian meshes for the multi-dimensional case.These kinetic models depend on a small parameter that can be seen as a"Knudsen"number.The method is asymptotic preserving in this Knudsen number.Also,the computational costs of the method are of the same order of a fully explicit scheme.This work is the extension of Abgrall et al.(2022)[3]to multidimensional systems.We have assessed our method on several problems for two-dimensional scalar problems and Euler equations and the scheme has proven to be robust and to achieve the theoretically predicted high order of accuracy on smooth solutions.

SELF-DEPENDENT LOCALITY PRESERVING PROJECTION WITH TRANSFORMED SPACE-ORIENTED NEIGHBORHOOD GRAPH

Locality preserving projection （LPP） is a typical and popular dimensionality reduction （DR） method,and it can potentially find discriminative projection directions by preserving the local geometric structure in data. However,LPP is based on the neighborhood graph artificially constructed from the original data,and the performance of LPP relies on how well the nearest neighbor criterion work in the original space. To address this issue,a novel DR algorithm,called the self-dependent LPP （sdLPP） is proposed. And it is based on the fact that the nearest neighbor criterion usually achieves better performance in LPP transformed space than that in the original space. Firstly,LPP is performed based on the typical neighborhood graph; then,a new neighborhood graph is constructed in LPP transformed space and repeats LPP. Furthermore,a new criterion,called the improved Laplacian score,is developed as an empirical reference for the discriminative power and the iterative termination. Finally,the feasibility and the effectiveness of the method are verified by several publicly available UCI and face data sets with promising results.

Projected Runge-Kutta methods for constrained Hamiltonian systems

Projected Runge-Kutta （R-K） methods for constrained Hamiltonian systems are proposed. Dynamic equations of the systems, which are index-3 differential-algebraic equations （DAEs） in the Heisenberg form, are established under the framework of Lagrangian multipliers. R-K methods combined with the technique of projections are then used to solve the DAEs. The basic idea of projections is to eliminate the constraint violations at the position, velocity, and acceleration levels, and to preserve the total energy of constrained Hamiltonian systems by correcting variables of the position, velocity, acceleration, and energy. Numerical results confirm the validity and show the high precision of the proposed method in preserving three levels of constraints and total energy compared with results reported in the literature.

A Discontinuous Galerkin Method with Penalty for One-Dimensional Nonlocal Diffusion Problems

There have been many theoretical studies and numerical investigations of nonlocal diffusion(ND)problems in recent years.In this paper,we propose and analyze a new discontinuous Galerkin method for solving one-dimensional steady-state and time-dependent ND problems,based on a formulation that directly penalizes the jumps across the element interfaces in the nonlocal sense.We show that the proposed discontinuous Galerkin scheme is stable and convergent.Moreover,the local limit of such DG scheme recovers classical DG scheme for the corresponding local diff usion problem,which is a distinct feature of the new formulation and assures the asymptotic compatibility of the discretization.Numerical tests are also presented to demonstrate the eff ectiveness and the robustness of the proposed method.

Clinical application of serial operations with preserving spleen

AIM: To evaluate the clinical application of serial operations with preservation of spleen. METHODS: Serial operations with preserving spleen were performed on 211 cases in our hospital from 1980 to 2000. The patient's age ranged from 13 to 56 years, averaging 38 years. Diseases included splenic injury in 171 cases, portal hypertension in 9 cases, splenic cyst in 10 cases, and the lesion of pancreatic body and tail in 21 cases. RESULTS: All the cases were cured, and 129 patients were followed up from 3 months to 3 years with the leukocyte phagocytosis test, detection of immunoglubin, CT,(99m)Tc scanning and ultrasonography. The results were satisfactory. CONCLUSION: The operations with preserving spleen were safe, feasible, and worth of clinical application.

Second order conformal multi-symplectic method for the damped Korteweg–de Vries equation

A conformal multi-symplectic method has been proposed for the damped Korteweg–de Vries(DKdV) equation, which is based on the conformal multi-symplectic structure. By using the Strang-splitting method and the Preissmann box scheme,we obtain a conformal multi-symplectic scheme for multi-symplectic partial differential equations(PDEs) with added dissipation. Applying it to the DKdV equation, we construct a conformal multi-symplectic algorithm for it, which is of second order accuracy in time. Numerical experiments demonstrate that the proposed method not only preserves the dissipation rate of mass exactly with periodic boundary conditions, but also has excellent long-time numerical behavior.

Two-layer cold storage method for pancreas and islet cell transplantation

The two-layer cold storage method (TLM) was f irst reported in 1988, consisting of a perfluorochemical (PFC) and initially Euro-Collins' solution, which was later replaced by University of Wisconsin solution (UW). PFC is a biologically inert liquid and acts as an oxygen-supplying agent. A pancreas preserved using the TLM is oxygenated through the PFC and substrates are supplied by the UW solution. This allows the pancreas preserved using the TLM to generate adenosine triphosphate during storage, prolonging the preservation time. In a canine model, the TLM was shown to repair and resuscitate warm ischemically damaged pancreata during preservation, improve pancreas graft survival after transplantation, and also improve the islet yield after isolation. Clinical trials using the TLM in pancreas preservation before whole-pancreas transplantation and islet isolation have shown promising outcomes. We describe the role of the TLM in pancreas and islet transplantation.

The Lie-group Shooting Method for Radial Symmetric Solutions of the Yamabe Equation

We transform the Yamabe equation on a ball of arbitrary dimension greater than two into a nonlinear singularly boundary value problem on the unit interval[0;1].Then we apply Lie-group shooting method(LGSM)to search a missing initial condition of slope through a weighting factor r 2(0;1).The best r is determined by matching the right-end boundary condition.When the initial slope is available we can apply the group preserving scheme(GPS)to calculate the solution,which is highly accurate.By LGSM we obtain precise radial symmetric solutions of the Yamabe equation.These results are useful in demonstrating the utility of Lie-group based numerical approaches to solving nonlinear differential equations.

The Outpatient Burch-Sling Procedure: A Nerve-Sparing Method for Correcting Female Urinary Incontinence

Conventional methods to treat urinary stress incontinence, including the Sling, Burch, and Pereyra modification methods, are limited by several shortcomings due to disrupted nerve and vaginal wall integrity. The nerve-sparing Burch-Sling method represents a surgical advancement through the use of a nerve-sparing sling to treat genuine stress urinary incontinence. The procedure involves retropubic urethropexy using the FDA-approved Burch-Sling device. In this technique, the vagina is elevated bilaterally at the urethrovesical junction to the mid-urethra toward Cooper’s ligament above the base of the bladder. Then, the anterior vaginal wall and fascia are used as an endogenous suburethral sling without dissection. Two hundred twenty cases were included in this study;two hundred patients underwent the outpatient nerve-sparing sling method, and the other twenty underwent the novel abdominal Burch method. There were no major complications. The follow-up duration ranged from 6 months to eight years. All procedures were performed at the U.S. Women’s Institute at a 400-bed hospital in Fountain Valley, CA.

High Order Semi-implicit Multistep Methods for Time-Dependent Partial Differential Equations

We consider the construction of semi-implicit linear multistep methods that can be applied to time-dependent PDEs where the separation of scales in additive form,typically used in implicit-explicit(IMEX)methods,is not possible.As shown in Boscarino et al.(J.Sci.Comput.68:975-1001,2016)for Runge-Kutta methods,these semi-implicit techniques give a great flexibility,and allow,in many cases,the construction of simple linearly implicit schemes with no need of iterative solvers.In this work,we develop a general setting for the construction of high order semi-implicit linear multistep methods and analyze their stability properties for a prototype lineal'advection-diffusion equation and in the setting of strong stability preserving(SSP)methods.Our findings are demonstrated on several examples,including nonlinear reaction-diffusion and convection-diffusion problems.

Strong-Stability-Preserving, K-Step, 5- to 10-Stage, Hermite-Birkhoff Time-Discretizations of Order 12

We construct optimal k-step, 5- to 10-stage, explicit, strong-stability-preserving Hermite-Birkhoff (SSP HB) methods of order 12 with nonnegative coefficients by combining linear k-step methods of order 9 with 5- to 10-stage Runge-Kutta (RK) methods of order 4. Since these methods maintain the monotonicity property, they are well suited for solving hyperbolic PDEs by the method of lines after a spatial discretization. It is seen that the 8-step 7-stage HB methods have largest effective SSP coefficient among the HB methods of order 12 on hand. On Burgers’ equations, some of the new HB methods have larger maximum effective CFL numbers than Huang’s 7-step hybrid method of order 7, thus allowing larger step size.

Structure-preserving properties of three differential schemes for oscillator system

A numerical method for the Hamiltonian system is required to preserve some structure-preserving properties. The current structure-preserving method satisfies the requirements that a symplectic method can preserve the symplectic structure of a finite dimension Hamiltonian system, and a multi-symplectic method can preserve the multi-symplectic structure of an infinite dimension Hamiltonian system. In this paper, the structure-preserving properties of three differential schemes for an oscillator system are investigated in detail. Both the theoretical results and the numerical results show that the results obtained by the standard forward Euler scheme lost all the three geometric properties of the oscillator system, i.e., periodicity, boundedness, and total energy, the symplectic scheme can preserve the first two geometric properties of the oscillator system, and the St？rmer-Verlet scheme can preserve the three geometric properties of the oscillator system well. In addition, the relative errors for the Hamiltonian function of the symplectic scheme increase with the increase in the step length, suggesting that the symplectic scheme possesses good structure-preserving properties only if the step length is small enough.