Criteria Of Purity Research Articles

Separation of guaifenesin enantiomers by simulated moving bed process with four operation modes

It has been validated experimentally and theoretically that guaifenesin enantiomers could be separated effectively by six-column simulated moving bed (SMB) process with Chiralcel OD stationary phase and n-hexane/ethanol mobile phase in our previous work. Based on the existed experimental conditions, we make further investigation for the effect of operation modes on the separation performance of SMB unit, including the asynchronous shifting of inlet/outlet ports (VariCol mode), varying feed flow rate (PowerFeed mode), and varying feed concentration (ModiCon mode) within the switching interval. The mathematical models of multicolumn SMB process are established, and the separation performances of SMB unit with four operation modes are compared at similar operation conditions. It is found that the effect of operation mode on the separation performance is more significant for the SMB system with a small number of columns. Compared with the conventional six-column SMB process at the purity criterion of single enantiomer in products up to 99%, ModiCon 1 with feed concentration adjusting “First low last high” within the switching interval is the best one with the productivity increasing 27.5% and the solvent consumption decreasing 21.7%; PowerFeed mode also has some improvement with the productivity increasing 10.6% and solvent consumption decreasing 8.7%; five-column VariCol mode has the improvement on the productivity increasing 26% due to the benefit to save one packed column with the expensive chiral stationary phase.

MICROBIOLOGICAL PURITY TESTING IN FOOD PRODUCTION AND MARKETING

The Rulebook on microbiological purity criteria prescribes the criteria of microbiologicalpurity and the frequency of control of equipment, devices, utensils, work surfaces, work clothes andworkers' hands in food production and marketing as well as in facilities and means of transport thatcome in contact with food in which there is a risk of occurrence and the spread of infectious diseases.Food facilities, means of transport, items, accessories and equipment that come in contact with foodmust be regularly cleaned and disinfected to avoid any risk of contamination, and food and staffmust be under regular supervision. Food handling staff must maintain a high level of personalhygiene and be trained in terms of food hygiene requirements. The aim of the study was to determinethe state of microbiological purity in food production and marketing in facilities and means oftransport that come into contact with food. As the test material we used swab samples from thesurfaces of equipment, devices, utensils, work surfaces, work clothes and workers' hands originatingfrom facilities for the production and marketing of food, restaurants and other catering facilitiesserving food, facilities in the field of education and social protection (facilities for accommodatingpersons) and means of transport that come into contact with food. A total of 3393 samples wereexamined in the course of self-control and official control during 2017. For microbiologicalexamination of swab samples, standard BAS ISO methods were used. The percent of swab samplesthat did not satisfy the Rulebook on the criteria of microbiological purity in 2017 was 5.20%. Inrelation to the total number of samples tested, 4.70% of the samples were unsatisfactory due to anincreased number of microorganisms, and 1.40% due to an increased number of enterobacteriaceae.Pathogenic microorganisms Salmonella spp. and Listeria monocytogenes are not detected in anyswab sample. The largest percent of unsatisfactory samples was in the category "hands of foodhandlers" and amounted to 7.30%

Effect of Re-entry Policy Implementation on Readmitted Girls’ Academic Performance in Mathematics in Selected Secondary Schools of Mufulira District in Zambia

Zambia is one of the countries in the Sub-Sahara Africa that has an established Re-Entry Policy. The policy was declared in 1997 and allows pregnant school girls to go to school. The aim is to create academically healthy learning institutions in which both girls and boys are free. As per findings of this research, the Re-Entry Policy has helped reduce gender discrepancies in terms of equity in education. Sad though, the paper has reviewed that most reentered girls fail mathematics, a thing that disadvantages them because mathematics is used as criteria of purity for admission into university and well-paid jobs. As such, the purpose of this study was to investigate the effect of Re-Entry Policy implementation on readmitted girl’s performance in mathematics. In order to achieve this aim, a qualitative research approach guided by some research questions and objectives was undertaken. Data relating to the research was collected through interview guides and questionnaires, and analyzed using narrative techniques. Furthermore, purposive sampling technique was used because the study targeted a specific group of people and characteristics. The conclusion made through the findings of this paper were that the perceived poor performance in mathematics by reentered girls is a ‘socio construct’ and not solely due to the Re-Entry Policy. This implies that the implementation of the policy is what is key; hence, the variations in performance for reentered girls in individual schools.

Accurate quantification of fourteen normal bone marrow cell subsets in infants to the elderly by flow cytometry.

Studies of normal bone marrow (BM) cell composition by flow cytometry are scarce. Presently, we aimed to quantify 14 cell subsets from infants to elderly patients. Cell subsets in BM samples from 180 individuals without morphologically abnormal leukocytes were analyzed using a single combination of eight antibodies: CD3/CD10/CD38/CD19/CD36/CD16/CD34/CD45. By comparison with the Holdrinet score, we first validated the immature granulocyte/neutrophil (IGRA/N) ratio as a readily obtainable criterion of BM sample purity in 145 cases. Then, the 115 highly pure samples were selected (IGRA/N ≥ 1.2) and analyzed according to age group. CD34+ myeloblasts became progressively more infrequent with age: median 1.4% in infancy to 0.5% in the elderly. Neutrophils increased: 10.7% to 22.8%; all other myeloid subsets, IGRA, eosinophils, basophils and monocytes remained stable: respectively 40.3% to 46.7%, 2.0% to 2.8%, 0.2% to 0.3%, and 4.4% to 5.0% throughout life. Erythroblasts were lower in children (8.4% to 10.3%) than in adults (12.5% to 15.1%). For lymphoid cells, hematogones and transitional B-cells decreased: 15.5% to 0.6% and 3.6% to 0.1%, respectively; mature lymphocytes remained stable: B-cells: 1.4% to 2.8%, T-cells: 5.8% to 8.7%, and NK-cells: 0.7% to 1.4%. Plasma cells varied slightly: 0.1% to 0.5%. Differences of about 40% were seen in moderately pure (IGRA/N: 0.5 to 1.2) BM samples. We thus provide the first values for 14 myeloid and lymphoid subsets characterizing BM cell composition in 5 age ranges. They should provide important information when screening patients for hematological disorders or abnormal bone marrow development. © 2018 International Clinical Cytometry Society.

A new two-strip TLC method for the quality control of technetium-99m mercaptoacetyl-triglycine (99mTc-MAG3)

Background99mTc-mercaptoacetyl-triglycine (99mTc-MAG3) has been used for dynamic renal imaging since about 30 years. Free pertechnetate (99mTcO4), colloidal 99mTc ((99mTcO2)n), 99mTc-tartrate (precursor), precomplexes (99mTc-(MAG3)x) and lipophilic 99mTc-MAG2 are the main radiochemical impurities that may occur in the preparation. The total amount of these impurities has to be identified before release of the product for patient administration to guarantee patient safety and good image quality. The European Pharmacopoeia suggests a method based on high-pressure liquid chromatography analysis in combination with a paper chromatography. This analytical method is time consuming, expensive and requires specially trained technicians. As a consequence, it is not widely applied in nuclear medicine radiopharmacies.ResultsWe developed a simple method for radiochemical purity testing of 99mTc-MAG3. The method is based on thin layer chromatography with two strips to be developed in parallel. Method validation was carried out in comparison to the official methods of the companies and to the European Pharmacopoeia method. It was tested on specificity, accuracy, robustness and precision.ConclusionThe proposed method is able to identify and quantify the sum of all impurities occurring in the preparation, respecting the acceptance criteria for the radiochemical purity defined by the official methods. Hydrophilic and lipophilic compounds are identified separately and results are obtained within less than 20 minutes. Our method is simple, cost effective, fast and is suitable for employing dose calibrators or radiometric scanners.

An algebraic study of extension algebras

We present simple conditions which guarantee a geometric convolution algebra to behave like a variant of the quasi-hereditary algebra. In particular, standard modules of the affine Hecke algebras of type $\mathsf{BC}$, and the quiver Schur algebras are shown to satisfy the Brauer-Humphreys type reciprocity and the semi-orthogonality property. In addition, we present a new criterion of purity of weights in the geometric side. This yields a proof of Shoji's conjecture on limit symbols of type $\mathsf{B}$ [Shoji, Adv. Stud. Pure Math. 40 (2004)], and the purity of the exotic Springer fibers [K, Duke Math. 148 (2009)]. Using this, we describe the leading terms of the $C^{\infty}$-realization of a solution of the Lieb-McGuire system in the appendix. In [K, arXiv:1203.5254], we apply the results of this paper to the KLR algebras of type $\mathsf{ADE}$ to establish Kashwara's problem and Lusztig's conjecture.

Expansion of Human Tregs from Cryopreserved Umbilical Cord Blood for GMP-Compliant Autologous Adoptive Cell Transfer Therapy

Umbilical cord blood is a traditional and convenient source of cells for hematopoietic stem cell transplantation. Thymic regulatory T cells (Tregs) are also present in cord blood, and there is growing interest in the use of autologous Tregs to provide a low-risk, fully human leukocyte antigen (HLA)-matched cell product for treating autoimmune diseases, such as type 1 diabetes. Here, we describe a good manufacturing practice (GMP)-compatible Treg expansion protocol using fluorescence-activated cell sorting, resulting in a mean 2,092-fold expansion of Tregs over a 16-day culture for a median yield of 1.26 × 109 Tregs from single-donor cryopreserved units. The resulting Tregs passed prior clinical trial release criteria for Treg purity and sterility, including additional rigorous assessments of FOXP3 and Helios expression and epigenetic analysis of the FOXP3 Treg-specific demethylated region (TSDR). Compared with expanded adult peripheral blood Tregs, expanded cord blood Tregs remained more naive, as assessed by continued expression of CD45RA, produced reduced IFN-γ following activation, and effectively inhibited responder T cell proliferation. Immunosequencing of the T cell receptor revealed a remarkably diverse receptor repertoire within cord blood Tregs that was maintained following in vitro expansion. These data support the feasibility of generating GMP-compliant Tregs from cord blood for adoptive cell transfer therapies and highlight potential advantages in terms of safety, phenotypic stability, autoantigen specificity, and tissue distribution.

English

Africa is experiencing reoccurrence of avian influenza outbreaks with huge negative impact on the economy of the continent as a result of high mortality rate and extreme contagiousness of the disease. The epidemiology of highly pathogenic avian influenza (HPAI) in Africa during the 2006-2008 outbreaks was complex and linked to movements of poultry commodities and wild birds. The peculiar risk factors, negative economic impact and the potential of being used as a biological weapon necessitates the development of a comprehensive control programme for the prevention or eradication of the disease. It is the opinion of this paper that development of new influenza vaccine technologies will provide affordable comprehensive control programmes for avian influenza prevention in Africa. To keep pace with the variability of the viruses, there is need for frequent redesign of avian influenza (AI) vaccines to match the circulating subtypes and on this is predicated the necessity of the development of influenza vaccine technology for a country, zone or region. The new vaccine technologies have been shown to have the potentials of giving vaccines with required criteria of purity, safety, efficacy, potency, low cost and short response time. The concept of most new vaccine technologies is biased towards removal of influenza virus from the system of vaccine development and at the same time obtaining more effective, potent and safe influenza vaccines. The new influenza vaccine technologies include gene-based, genomics-based, subunit, plant-based, VLPs and universal vaccine technologies. These technologies have the potential to provide vaccines that will not just be used as intervention strategies to lessen severity of the disease but as preventative vaccination. Also routine vaccination will not just be as a tool of last option in disease endemic areas, but one to prevent the disease. Key words: Technologies, avian influenza, vaccine, eradication, prevention, comprehensive, control, programme.

A chromatographic objective function to characterise chromatograms with unknown compounds or without standards available

Getting useful chemical information from samples containing many compounds is still a challenge to analysts in liquid chromatography. The highest complexity corresponds to samples for which there is no prior knowledge about their chemical composition. Computer-based methodologies are currently considered as the most efficient tools to optimise the chromatographic resolution, and further finding the optimal separation conditions. However, most chromatographic objective functions (COFs) described in the literature to measure the resolution are based on mathematical models fitted with the information obtained from standards, and cannot be applied to samples with unknown compounds. In this work, a new COF based on the automatic measurement of the protruding part of the chromatographic peaks (or peak prominences) that indicates the number of perceptible peaks and global resolution, without the need of standards, is developed. The proposed COF was found satisfactory with regard to the peak purity criterion when applied to artificial peaks and simulated chromatograms of mixtures built using the information of standards. The approach was applied to mixtures of drugs containing unknown impurities and degradation products and to extracts of medicinal herbs, eluted with acetonitrile–water mixtures using isocratic and gradient elution.

Control of Polymorphism in Continuous Crystallization via Mixed Suspension Mixed Product Removal Systems Cascade Design

Control of polymorphism of the enantiotropic p-aminobenzoic acid at either the α or β polymorph while maintaining high yield was achieved by mixed suspension mixed product removal (MSMPR) cascade design. A systematic approach was developed to identify the operational window of the process variables, stage temperature and residence time, in which the stringent polymorph purity criterion (>95 wt %) and high yield were met. The comprehensive understanding of the polymorphism of the model compound, p-aminobenzoic acid, was the key for the identification of the operational window. On the basis of single-stage MSMPR experiments, three temperature regimes—thermodynamic control, energy barrier control, and kinetic competition—were identified, and the interplay between the crystallization kinetics and the thermodynamics in each regime was elucidated. Experimental studies also demonstrated the first polymorph specific MSMPR for enantiotropic systems. Single-stage MSMPRs at low temperature, e.g., 5 °C, were found to...

A brief history of water filtration/sedimentation

For millennia the search for ‘pure’ water has been pursued by humans. Criteria for purity have become more complex, more rigid, and more quantitative over time; however, the principles, methods, and material for purifying water have remained remarkably similar from the earliest recorded information of 2000 BC. The scope of this paper is to present a brief history of water filtration and sedimentation practices for potable water management extending from the ancient times to the 19th century. It is not an exhaustive presentation, but instead presents some of the most important advances in water supply since the beginning of human's quest for pure water. M. N. Baker and M. J. Taras in 1981 presented an excellent overview of this quest, especially during the 17th to the 20th century.

Synthesis of pure iron(II) mesotetraphenylchlorin complexes via a versatile general method of iron insertion into chlorins

An original synthesis of pure (tetraphenylchlorinato)iron(III) chloride (1) is reported. Insertion of iron is achieved using 1.2 equivalents of cadmium acetate in DMF at 110°C, followed by a transmetallation reaction (in situ) using 8 equivalents of iron(II) chloride tetrahydrate in acetone at 60°C. The 1H NMR shifts at 25°C of the pyrrole protons varied from 60 to 100ppm. The absence of the signal at 80ppm related to undesired (tetraphenylporphirinato)iron(III) chloride is a purity criterion and shows the importance of the method used.Reaction of (tetraphenylchlorinato)iron(III) chloride (1) with four equivalents of tert-butyl isocyanide, 2,6-xylyl isocyanide and dimethylphenylphosphine in the presence of zinc amalgam in dichloromethane (DCM) afforded pure FeII(TPC)(t-BuNC)2 (2), FeII(TPC)(2,6-xylylNC)2 (3) and FeII(TPC)[P(Me)2Ph]2 (4) respectively.

Observations on the Preparation of β-Lactose Octaacetate

Attempts to substantially increase the relative proportion of β-lactose octaacetate in products of acetylation of α-lactose monohydrate using various acetylation protocols failed. Nevertheless, the revised protocol for isolation and crystallization, based on the classical work by Hudson and Johnson, rendered preparation of β-lactose octaacetate less labor intensive. It is proposed that the melting point and [α]D value are not reliable criteria of purity of β-lactose octaacetate, which can be confidently determined by 1H NMR spectroscopy.

Historicizing Edai Siabo: a Contemporary Argument about the Pre‐colonial Past among the Motu‐Koita of Papua New Guinea

ABSTRACT In the 1970s the Motu‐Koita, traditional inhabitants of what is now the National Capital District of Papua New Guinea, inaugurated a yearly cultural festival thematically based on traditional coastal trading voyages known as hiri. Contestation over the location and commercialization of the festival in the capital city developed in the new century as one distant village claimed to ‘own’ the hiri. The Motu‐Koita view of their past and their identity has been affected by their encounter with Christianity, colonialism and its aftermath, and the rhetoric of the villagers’ claims drew on criteria of authenticity, cultural purity, and exclusiveness which are arguably contemporary rather than ‘traditional’. This article reviews Motu‐Koita history, the story of the origin of the hiri, and the local politics of the cultural festival. It attempts to understand the way the past, which was formerly mythopoeically invoked, is being historicized and thereby fixed in new local discourses of cultural and heritage rights and ownership, as Melanesians come to terms with the effects of global processes on their traditions and other resources.

Crystal Structure, Spectroscopy and Crystal Field Analysis of Substituted 1,10‐Phenanthroline–Europium Complexes

AbstractCrystal structures and vibrational and electronic spectroscopic data are reported for europium(III) complexes with 5(or 4)‐R‐1,10‐phenanthroline (phen) ligands (R = chloro, methyl, nitro, amino). All complexes comprise a 10‐coordinate Eu3+ ion with three chelating nitrato anions and two bidentate phen ligands. The crystal structures are of three distinct types with space groups C2/c, P21/n and P. The room‐temperature emission spectra are dominated by the forced electric dipole 5D0 → 7F2 emission of Eu3+. The excitation spectra show that the triplet donor state of the nitro‐substituted complex has a lower energy than the other complexes and the lower luminescence quantum efficiency of this complex is rationalized. The emission spectra recorded at 10 K have been compared with those of the corresponding Eu3+‐doped yttrium complexes using different excitation lines as a criterion of sample purity. The spectrum of the unsubstituted phen complex is more clearly resolved than those of the other complexes and this has been attributed to disorder resulting in inhomogeneous broadening. A detailed crystal field analysis is given for the phen complex from the fitting of 24 crystal field energy levels. A comparison with other complexes has been made through derived second‐rank crystal field strengths. No simple relationships have been derived from comparisons of energy levels, spectral line positions, or second‐rank crystal field strengths with crystallographic data or Taft constants.

A Mereological Interpretation of the Phase Rule

Gibbs's phase rule treats mixtures by relating the number of independent variables governing their state to the numbers of phases and independent substances. For the case of a single substance, it provides a criterion of purity. But where more substances are involved, the notion of independent substance is less readily understood. Textbook writers sometimes use algebraic terminology in ways that are suggestive but cannot be taken as literally accurate. I suggest that a mereological interpretation applies to these cases, as it captures more concisely the insights underlying the use of algebraic terminology and illuminates the general notion of substance.

Production of pharmaceutical‐grade recombinant aprotinin and a monoclonal antibody product using plant‐based transient expression systems

Plants have been proposed as an attractive alternative for pharmaceutical protein production to current mammalian or microbial cell-based systems. Eukaryotic protein processing coupled with reduced production costs and low risk for mammalian pathogen contamination and other impurities have led many to predict that agricultural systems may offer the next wave for pharmaceutical product production. However, for this to become a reality, the quality of products produced at a relevant scale must equal or exceed the predetermined release criteria of identity, purity, potency and safety as required by pharmaceutical regulatory agencies. In this article, the ability of transient plant virus expression systems to produce a wide range of products at high purity and activity is reviewed. The production of different recombinant proteins is described along with comparisons with established standards, including high purity, specific activity and promising preclinical outcomes. Adaptation of transient plant virus systems to large-scale manufacturing formats required development of virus particle and Agrobacterium inoculation methods. One transient plant system case study illustrates the properties of greenhouse and field-produced recombinant aprotinin compared with an US Food and Drug Administration-approved pharmaceutical product and found them to be highly comparable in all properties evaluated. A second transient plant system case study demonstrates a fully functional monoclonal antibody conforming to release specifications. In conclusion, the production capacity of large quantities of recombinant protein offered by transient plant expression systems, coupled with robust downstream purification approaches, offers a promising solution to recombinant protein production that compares favourably to cell-based systems in scale, cost and quality.

Substance and Time

‘Water is H2O’ is naturally construed as an equivalence. What are the things to which the two predicates ‘is water’ and ‘is H2O’ apply? The equivalence presupposes that substance properties are distinguished from phase properties. A substance like water (H2O) exhibits various phases (solid, liquid, gas) under appropriate conditions, and a given (say liquid) phase may comprise several substances. What general features distinguish substance from phase properties? I tackle these questions on the basis of an interpretation of a theorem of thermodynamics known as Gibbs' phase rule which systematically relates these two kinds of feature of matter. The interpretation develops the idea that the things substance and phase predicates apply to are quantities of matter which sustain mereological relations and operations and exploits these mereological features in distinguishing the two kinds of property. Gibbs' phase rule is a macroscopic principle applicable for macroscopic intervals of time. Bringing intervals of time into the picture calls for a more detailed consideration of the relation between macroscopic equilibria and the corresponding dynamic equilibria at the microlevel and throws into question the simple idea that quantities can always be regarded as collections of molecules. The account provides some insight into how the continuous, macroscopic conception of matter (‘gunk’) is reconciled with the discrete microscopic conception and illuminates the interpretation of substances present in mixtures. 1. Introduction 2. Time Dependence 3. Microentities 4. Criteria of Purity and the Notion of Substance 5. Derivation and Further Illustrations of the Phase Rule 6. Microscopic Species in Water 7. Dynamic Equilibria and the Phase Rule 8. The Time of Predication 9. Independent Substances 10. The General Conception of a Mixture 11. Conclusion

Quantitative iterative target transformation factor analysis

AbstractTraditionally, improvement of the constrained alternating least squares (ALS) solution has been executed by the addition of a priori information in the initial estimates and or constraints. However, there are cases where this information simply does not exist or is impossible to acquire under the process conditions. Therefore, new strategies are required to produce starting estimates close to the actual solution without the need of a priori information. Quantitative iterative target transformation factor analysis (QITTFA) is developed as a solution to this problem. The QITTFA approach combines the strengths of both iterative target transformation factor analysis (ITTFA) and simple‐to‐use interactive self‐modelling mixture analysis (SIMPLISMA) to (1) produce a solution space spanned by the independent factors such that the variance contribution due to noise is reduced, (2) to iteratively refine the solutions space prior to ALS and (3) to select the most pure variables from the refined solution space using the purity criterion. It has been observed that the QITTFA approach markedly improves the conventional SIMPLISMA and second derivative SIMPLISMA performance in the presence and absence of selectivity. In addition, components of differing spectral characteristics (narrow or broad spectral features) can be resolved, without a priori knowledge of the shapes of the pure components. This has been demonstrated with a simulated high performance liquid chromatography‐diode array detection (HPLC‐DAD) dataset, a laboratory‐based UV–Vis calibration dataset and a gaseous near infrared (NIR) dataset from an industrial process. Copyright © 2007 John Wiley & Sons, Ltd.

Evaluation of endospore purification methods applied to Bacillus cereus

Research on spore inactivation techniques requires highly pure spore suspensions, but the efficacy of commonly used purification methods has not been systematically compared. By providing this comparison, the present study will help researchers improve the consistency and validity of their experiments. The current study evaluated alternative purification methodologies applied to Bacillus cereus endospores on the basis of criteria of purity, yield, time investment and effect on integrity of spores. The ASTM E2111-00, ethanol, heat shock, daily water washes and lysozyme treatment methods were applied to B. cereus cultures incubated for 3 and 10 days. Purities achieved ranged from 67 to 99% spores as a proportion of total colony forming units in the purified suspension, whereas yields ranged from less than 1 to 39% spores in proportion to total colony forming units of B. cereus culture. TEM images showed that only lysozyme treatment substantially altered spore morphology. Ethanol treatment is optimum for 3-day B. cereus cultures, whereas the ASTM method is most favorable for 10-day-old cultures. Lysozyme treatment is the least attractive purification method because of its large time investment and damage to spores.