Racism and discrimination Research Paper Example | Topics and Well Written Essays - 250 words - 1

Racism and discrimination - Research Paper Example Whiteness and identity issues have stood at the center of racism in Canada (Lund & Carr, 2010). Lobby groups’ advocacy against racism in Canada continues to mobilize the Canadian population against racism and discrimination. The interactions and relations among Canadians, people of color, and aboriginals cannot be described in the best words. However, the continued social, economic, and political efforts to curb racism in the country serves as a vital step towards societal unity in Canada. â€Å"Visible minority† is a common term in Canada. Colored people in Canada are referred to using the term. In fact, Canada’s legal framework also recognizes this term and further integrates it into the legal provisions relative to racism and discrimination. This comes amid persistent efforts to fight racism and discrimination in the country. Ghosh, R. (2012). Multicultural Teacher Education in Canada. In Craft, M. Teacher Education in Plural Societies: An International Review. New York: Routledge. http://books.google.co.ke/books?hl=en&lr=&id=GVMkNEH2Um8C&oi=fnd&pg=PA45 &dq=racism+in+Canada+2012&ots=SSTZjKFOzj&sig=frXz89Wk8InmiT29swSptxDxY bk&redir_esc=y#v=onepage&q&f=false Lund, D. & Carr, P. (2010). Exposing Privilege and Racism in the Great White North: Tackling Whiteness and Identity Issues in Canadian Education. Multicultural Perspectives, Volume 12, Issue 4, 229-234. http://www.tandfonline.com/doi/abs/10.1080/15210960.2010.527594 Walker, B. (2008). The History of Immigration and Racism in Canada: Essential Readings. Toronto: Canadian Scholars’ Press.

Nursing informatics Essay Example | Topics and Well Written Essays - 2250 words

Nursing informatics - Essay Example The key aspect of integrated clinical systems is that they help health service providers gather and store health care related data as a part of the general workflow. In this scenario, an electronic health record system facilitates the health care service providers to get data for billing, the doctor to perceive developments in the efficiency of treatments, a medical researcher to examine the effectiveness of medicine in patients with co-morbidities and a nurse to report an unfavorable reaction. Additionally, an EHR system puts together data to deal with different requirements. The basic goal is to gather data once, then utilize it numerous times. The majority of commercial electronic health records join together data from the large subsidiary services or departments, such as laboratory, pharmacy and radiology, through a wide variety of health care actions (i.e. medication administration records [MAR], nursing plans and medical physician orders). In other words, the use of an EHR system is the next step in the continuous development of healthcare sector that can reinforce the link between healthcare service providers and patients, because the data, and the appropriate and timely accessibility of it, allow health service providers to provide better care and make better decisions ... personal information that is stored in EHRs can be: (TechTarget, 2011; Centers for Medicare & Medicaid Services, 2012; National Institutes of Health, 2006) Family history Contact information Allergies Insurance information Information regarding visits to health care specialists Immunization position Information regarding some conditions or diseases A list of medications Records of hospitalization Information regarding some surgeries or procedures performed What are Advantages of EMRs? Healthcare firms can save space by reducing paper work desired for hospitals, medical offices or insurance businesses. One more benefit of electronic health records is that they enable health care groups to organize health care services. In addition, the use of electronic health record systems can save a lot of time. Although faxing and email helps one doctor to obtain data and information from another laboratory or doctor, but for this they had to wait for a long time. But with EHRs, healthcare profess ionals can have immediate access to a patient’s details and data, such as lab tests, x-rays and details of recommendations or allergies, in this way they will be authorized to act right away, as a result saving a lot of precious time (Ellis-Christensen, 2012; Ausmed Education Pty Ltd. , 2012; Outlook Associates, 2010). Given below are some of major advantages of EHRs: (Ausmed Education Pty Ltd. , 2012) Improve communication among healthcare professionals Reduce repetition of information Information is accessible to healthcare professionals remotely All healthcare professionals can access same latest information Improve loyalty and reliability of healthcare Information less likely to be lost or destroyed (as it can happen in case of paperwork) Can more correctly store financial data

Theories Regarding How the Pyramids at Giza Were Constructed Essay Example for Free

Theories Regarding How the Pyramids at Giza Were Constructed Essay The Great Pyramid of Giza is one of the key structures listed in the seven wonders of the ancient world. It is important to notice that what makes this structure supreme and memorable? This wonder was the tallest man made composition in 3800 years which is not only a will to its robustness but to mark it as the most remarkable structures. This monument exemplifies the accomplishments and advancements of architecture in Egypt (www. personal. psu. edu))t. There are many mysteries that are raised for its construction and also introduce different theories. It is important to notice that it is not the pyramid that is eye capturing but the method and process of creating it is certainly fascinating. There are two particular theories such as transport theory which is presented by engineer and inventor, Andrzej Bochnacki and Limestone concrete theory by Materials scientist, Joseph Davidovits that hold the focus of many historians and scientists Discussion One of the most refined pyramid construction theories has been proposed by Polish engineer, Andrzej Bochnacki. In the book of â€Å"Different Story about Pyramids†, Andrzej suggests very inventive technology for moving the pyramid blocks from the pits to the construction place. He presents the method from which the stones moved to making the entire pyramid. He said that they must have made the paper boats which were placed on the top of the blocks and knotted up with ropes (Bochnacki, 1994). These movable boats were in wait to raise the water of Nile and so they can be easily dragged to a preferred destination. The easiest way was to drag them to the west region of Nile where water flooded the fields. There is a sketch that portrays the moving of stones for making pyramid. Moreover, there is another great theory presented by Materials scientist, Joseph Davidovits. He claimed that Pyramid’s block are not the carved stone, but was mostly made from limestone concrete and they were forcefully thrown like modern concrete. As per this theory, soft limestone with high kaolinite capacity was tapped in the gully on the southern side of the Giza Plateau. He suggested that the limestone was then dissolved in Nile pools till it became slurry. It is important to notice that lime and natron are greatly in use in mummification by Egyptians. It might be possible that the pool were then allowed to evaporate, leaving a clay-like mixture. The scientist mentioned that this wetly concrete material will be carried to the site of construction where it would be filled into recyclable wooden molders and after few days it would undergo in a chemical reaction. , he suggested that new blocks can be casted in the place on the top of other blocks. This composition was tested by using the similar compounds which were brought out at the institute of geopolymer in northern France. It was discovered that these limes could pile a structure of 1. 3- to 4. 5-ton blocks in few weeks (Barsoum, Ganguly Hug, 2006). But it is essential to notice that this theory was not accepted by the mainstream of academics. Davidovits’ method does not cover the entire reasoning as the stones weighted more than 10 tons and his theory defines only 4. 5 tons growth. Moreover, different Geologists have cautiously inspected the suggested technique of Davidovits and concluded that his reasoning came from innate limestone tapped in the Formation of Mokattam. This theory is currently supported by Michel Barsoum, who is a researcher of material science. Barsoum and his fellows printed their findings at Drexel University which supports the theory of Davidovits in 2006 in the Journal of the American Ceramic Society. They further discussed that air bubbles and mineral compounds are the samples of limestone and the blocks of pyramid are not made up of natural limestone. I think that this theory holds certain reasons as a petrographer, Dipayan Jana also made a presentation in 2007 to the ICMA, in which he talks about the work of Barsoum and Davidovit and concluded that we are more far to accept the remote possibility of manmade structure of pyramid stones. Conclusion Certainly, the construction of Pyramid is mystery and many scientists and researchers have tried different methods to resolve this puzzling mystery. In my opinion, the theory of limestone concrete is more appropriate in its reasoning as it is based on the mere research of the stone material and certainly portrays the accuracy. The mystery holds great significance as it is about one of the world’s wonder that could not be easily left my scientist. The resolution to this mystery seems no ending as there are many discussions and debates have taken place regarding this construction enigma. The entire study of the Construct Pyramids at Giza was very interesting to know about the interest of people in ancient monuments and their origins. It certainly enhances the understanding about the cultural and historical usage of things and how people’s hard work and traditional ways brought outstanding creations.

High Performance Liquid Chromatography (HPLC) 214

High Performance Liquid Chromatography (HPLC) 214 Introduction High performance liquid chromatography 214 is the most widely used of all of the analytical separation techniques. The reasons for the popularity of the method is its sensitivity, ready adaptability to accurate quantitative determinations, suitability for separating non-volatile species or thermally fragile ones, wide spread applicability to substance that are of prime interest to industry, many fields of science and the public. The applications of chromatography have grown explosively in the last fifty years owing not only to the development of several new types of chromatographic techniques but also to the growing need by scientist for better methods for characterizing complex mixtures. General methodology for the development of new HPLC methods 215-228 HPLC method development follows the series of steps summarized below. Information on sample, objective of separation. Need for special HPLC procedure, sample pretreatment etc. Choice of detector and detector settings. Choosing LC method, preliminary run, estimation of best separation conditions. Optimization of separation conditions. Check for problems or requirement for special procedure. a) Recovery of purified material   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   b) Quantitative calibration  Ã‚  Ã‚  Ã‚  Ã‚   c) Qualitative method Validate method for routine laboratory use. A good method development strategy should require only as many experimental runs as are necessary to achieve the desired final result. Finally, method development should be simple as possible, yet it should allow the use of sophisticated tools such as computer modeling if these are available. Before the beginning of method development, it is necessary to review what is known about the sample in order to define the goals of separation. The kinds of sample related information that can be important are summarized in Table-7.1. Table-8.1 Important information concerning sample composition and properties Number   of compounds present in the sample Chemical structures of components Molecular weights of compounds PKa values of compounds UV spectra of compounds Concentration range of various compounds in samples of interest Sample solubility   Ã‚   The chemical composition of the sample can provide valuable clues for the best choice of initial conditions for an HPLC separation. Objectives of separation The objectives of HPLC separation need to be specified clearly include. The use of HPLC to isolate purified sample components for spectral identification or quantitative analysis. It may be necessary to separate all degradants or impurities from a product for reliable content assay. In quantitative analysis, the required levels of accuracy and precision should be known (a precision of  ± 1 to 2% is usually achievable). Whether a single HPLC procedure is sufficient for raw material or one or more formulations and / or different procedures are desired for the analysis of formulations? When the number of samples for analysis at one time is greater than 10, a run time of less than 20 min. will be oftenly important. Knowledge on the desired HPLC equipment, experience and academic training the operators have. Sample pretreatment and detection Samples for analysis come in various forms such as: Solutions ready for injections. Solutions that require dilution, buffering, addition of an internal standard or other volumetric manipulation. Solids that must first be dissolved or extracted. Samples that require pretreatment to remove interference and/or protect the column or equipment from damage. Most samples for HPLC analysis require weighing and / or volumetric dilution before injection. Best results are often obtained when the composition of the sample solvent is close to that of the mobile phase since this minimizes baseline upset and other problems. Some samples require a partial separation ( pretreatment) prior to HPLC, because of need to remove interference, concentrate sample analytes or eliminate â€Å"column killer†. In many cases the development of an adequate sample pretreatment can be challenging than achieving a good HPLC separation. The detector selected should sense all sample components of interest. Variable-wavelength ultraviolet (UV) detectors normally are the first choice, because of their convenience and applicability for most samples. For this reason information on the UV spectra can be an important aid for method development. When the UV response of the sample is inadequate, other detectors are available (flourescence, electrochemical, PDA etc.) or the sample can be derivatized for enhanced detection. Developing the method for the separation Selecting an HPLC method and initial conditions If HPLC is chosen for the separation, the next step is to classify the sample as regular or special. Regular samples means typical mixtures of small molecules (    Table-8.2 Handling of special sample Sample Requirements Inorganic ions Detection is primary problems; use ion chromatography Isomers Some isomers can be separated by reversed-phase HPLC and are then classified as regular samples; better separations of isomers are obtainable using either (1) normal-phase HPLC or (2) reversed-phase separations with cyclodextrin-silica columns. Enantiomers These compounds require â€Å"chiral† conditions for their separations. Biological Several factors make samples or this kind â€Å"special†; molecular conformation, polar functionality and a wide range of hydrophobicity. Macromolecules â€Å"Big† molecules require column packing with large pores  Ã‚  (>> 10-nm diameters); in addition, biological molecules require special conditions as noted above. Table-8.3 Preferred experimental conditions for the initial HPLC separation Separation variable Preferred initial choice Column Dimensions (length, ID) 15 x 0.46 cm Particle size 5 mma Stationary phase C8 or C18 Mobile phase Solvent A and B Buffer-acetonitrile % B 80-100%b Buffer (compound, pH, concentration) 25mM potassium phosphate 2.0 Additives (e.g., amine modifiers, ion pair reagents) Do not use initially Flow rate 1.5–2.0 ml/min Temperature 35-45 ºC Sample Size Volumed >25 mL Weightd B : Polar solvent  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   a 3.5 mm particles are an alternative using a 7.5 cm column b For an initial isocratic run; an initial gradient run is preferred. c No buffer required for neutral samples; for pH d Smaller values required for smaller-volume columns (e.g., 7.50.46-cm, 3.5-mm column). Table-8.4 Physical properties of silica supports for some C 18 columns Column (mL/mL) Pore diameter (nm) Surface area (m2/g) Percent Porosity Hypersil ODS 12 170 57 LiChrosorb C18 10 355 71 Novapak C18 6 N/Aa N/Aa Nucleosil C18 10 350 69` Symmetry C18 10 335 66 Zorbax ODS 6 300 55 Zorbax Rx, SB, XDB 8 180 50 a N/A : Not available On the basis of the initial exploratory run isocratic or gradient elution can be selected as most suitable. If typical reversed-phase conditions provide insufficient sample retention, suggesting the use of either ion pair on normal phase HPLC. Alternatively, the sample may be strongly retained with 100% acetonitrile as mobile phase, suggesting the use of non-aqueous reversed-phase (NARP) chromatography or normal phase HPLC. Some characteristics of reversed-phase and other HPLC methods are summarized below. Table-8.5 Characteristics of primary HPLC methods Method / description/ columns Preferred method Reversed-phase HPLC Uses water – organic mobile phase Columns: C18 (ODS), C8, phenyl, trimethylsilyl (TMS), Cyano First choice for most samples, especially neutral or non-ionisable compounds that dissolve in water-organic mixtures Ion-pair HPLC Uses water-organic mobile phase a buffer to control pH and an ion pair reagent. Column : C18, C8, cyano. Acceptable choice for ionic or ionizable compounds, especially bases or cations. Normal phase HPLC Uses mixtures of organic solvents as mobile phase Columns: Cyano, diol, amino and silica. Good second choice when reversed-phase or ion-pair HPLC is ineffective, first choice for lipophilic samples that do not dissolve well in water-organic mixtures, first choice for mixtures of isomers and for preparative-scale HPLC (silica best) Getting started on method development One approach is to use an isocratic mobile phase of some average solvent strength (e.g., 50%) organic solvent. A better alternative is to use a very strong mobile phase with (80-100% B), then reduce %B as necessary. The initial separation with 100%B results in rapid elution of the entire sample, but few groups will separate. Decreasing solvent strength shows the rapid separation of all components with a much longer run time, with a broadening of later bands and reduced detection sensitivity. Improving the separation and repeatable separation Generally the chromatographers will consider several aspects of the separation, as summarized in Table-8.6. Table-8.6 Objectives of separation in HPLC method development Objectivesa Comment Resolution Precise and rugged quantitative analysis requires that Rs be greater than 1.5. Separation time Quantitation   Ã‚ £ 2% (1 SD) for assays;  £ 5% for less-demanding analysis;  £15% for trace analysis. Pressure Peak height Narrow peaks are desirable for large signal / noise ratios Solvent consumption   Minimum mobile-phase use per run is desirable. a Roughly in order of decreasing importance but may vary with analysis requirements. Separation or resolution is a primary requirement in quantitative HPLC. The resolution (Rs) value should be maximum (Rs>1.5) favours maximum precision. Resolution usually degrades during the life of the column and can vary from day to day with minor fluctuations in separation conditions. Therefore, values of Rs = 2 or greater should be the goal during method development for simple mixtures. Such resolution will favour both improved assay precision and greater method ruggedness. Some HPLC assays do not require base line separation of the compounds of interest (qualitative analysis). In such cases only enough separation of individual components is required to provide characteristic retention times for peak identification. The time required for a separation (run time = retention time for base band) should be as short as possible and the total time spent on method development is reasonable (runtimes 5 to 10 minutes are desirable). Conditions for the final HPLC method should be selected so that the operating pressure with a new column does not exceed 170 bar (2500 psi) and upper pressure limit below 2000 psi is desirable. There are two reasons for that pressure limit, despite the fact that most HPLC equipment can be operated at much higher pressures. First, during the life of a column, the back pressure may rise by a factor of as much as 2 due to the gradual plugging of the column by particular matter. Second, at lower pressures When dealing with more challenging samples or if the goals of separation are particularly stringent, a large number of method development runs may be required to achieve acceptable separation. Repeatable separation As the experimental runs described above are being carried out, it is important to confirm that each chromatogram can be repeated. When changing conditions (mobile phase, column, and temperature) between method development experiments, enough time must elapse for the column to come into equilibrium with a new mobile phase and temperature. Usually column equilibration is achieved after passage of 10 to 20 column volumes of the new mobile phase through the column. However, this should be confirmed by carrying out a repeat experiment under the same conditions. When constant retention times are observed in two such back-to-back repeat experiments ( ± 0.5% or better), it can be assumed that the column is equilibrated and the experiments are repeatable. Completing the HPLC method development The final procedure should meet all the objectives that were defined at the beginning of method development. The method should also be robust in routine operation and usable by all laboratories and personnel for which it is intended. Quantitation and method validation One of the strengths of HPLC is that is an excellent quantitative analytical technique. HPLC can be used for the quantitation of the primary or major component of a sample (including pure samples) for mixture of many compounds at intermediate concentrations and for the assessment of trace impurity concentrations in matrix. Method validation, according to the United States Pharmacopoeia (USP), is performed to ensure that an analytical methodology is accurate, specific, reproducible and rugged over the specified range that an analyte will be analysed. Method validation provides an assurance of reliability during normal use and is sometimes described as the process of providing documented evidence that the method does what it is intended to do. According to USP, the method validation involves eight steps as given below. Precision Accuracy Limit of detection Limit of quantitation Specificity Linearity and range Ruggedness Robustness Precision and accuracy: Already discussed in chapter-1. Linearity The linearity of the method is a measure of how well a calibration plot of response v/s concentration approximates a straight line, or how well the data fit to the linear equation. Y = aX + b Where ‘Y’ is the response, ‘X’ is the concentration, ‘a’ is the slope and ‘b’ is the intercept of a line fit to the data. Ideally, a linear relationship is preferred (b = 0) because it is more precise, easier for calculations and can be defined with fewer standards. Also, UV detector response for a dilute sample is expected to follow Beer’s law and be linear. Therefore, a linear calibration gives evidence that the system is performing properly throughout the concentration range of interest. Generally in HPLC, if we are using internal standard, then the linearity plot is to be drawn by taking concentration of the analyte on x-axis and the ratio of area under the curve (AUC) of analyte to AUC of internal standard (IS) on y-axis. The resulting plot slope, intercept and correlation coefficient provide the desired information on linearity. A linearity correlation coefficient above 0.999 is acceptable for most methods. Limit of detection (LOD) The limit of detection (LOD) is the smallest concentration that can be detected reliably. The LOD represents the concentration of analyte that would yield a signal-to-noise (S/N) ratio of 3. Limit of quantitation (LOQ) The LOQ is the concentration that can be quantitated reliably with a specified level of accuracy and precision. The LOQ represents the concentration of analyte that would yield a signal-to-noise ratio of 10. LOD and LOQ can be determined by using the following expressions. LOD  Ã‚  Ã‚   =  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   3 X N / B LOQ  Ã‚  Ã‚   =  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   10 X N / B Where N is the noise estimate, is the standard deviation of the peak area ratio of analyte to IS (5 injections) of the drugs. B is the slope of the corresponding calibration curve. The LOD and LOQ values determined during method validation are affected by the separation conditions, columns, reagents and especially instrumentation and data systems. Ruggedness Method ruggedness is defined as the reproducibility of results when the method is performed under actual use conditions. This includes different analysts, laboratories, columns, instruments, sources, chemicals, solvents etc. method ruggedness may not be known when a method is first developed, but insight is obtained during subsequent use of that method. Robustness The concept of robustness of an analytical procedure has been defined by the ICH as â€Å" a measure of its capacity to remain unaffected by small, but deliberate variations in method parameters†. The robustness of a method is the ability to remain unaffected by small changes in parameters such as pH of the mobile phase, temperature, percentage of organic solvent and buffer concentration etc. to determine robustness of the method experimental conditions were purposely altered and chromatographic characteristics were evaluated. To study the pH effect on the retention (K1) of the drug, buffer pH is to be changed by 0.2 units. At certain point, retention will increase at any pH above and below of the pH unit. The effect of temperature on the retention characteristics (K1) of the drug is to be studied by changing the temperature in steps 2 ºC from room temperature to 80 ºC and see the effect of temperature on the resolution and peak shape. Effect of percentage organic strength on retention is to be studied by varying the percentage of organic solvents like acetonitrile, methanol etc. from 0 to 2% while the other mobile phase contents are held constant and observe the K1. At certain point decreases in K1 observed with increase in the level of organic solvent. Effect of buffer concentration should be checked at three concentration levels i.e. 0.025 M, 0.05 M and 0.1 M and observe retention time and resolution. Stability To generate reproducible and reliable results, the samples, standards and reagents used for the HPLC method must be stable for a reasonable time (e.g., One day, one week, one month, depending on the need). For example, the analysis of even a single sample may require 10 or more chromatographic runs to determine system suitability, including standard concentrations to create a working analytical curve and duplicate or triplicate injections of the sample to be assayed. Therefore, a few hours of standard and sample solution stability can be required even for a short (10 min.) separation. When more than one sample is analyzed, automated, over night runs often are performed for better laboratory efficiency. Typically, 24 hours stability is desired for all solutions and reagents that need to be prepared for each analysis. Mobile phases should be chosen to avoid stability problems, especially the use of amine additives or specific solvents. For example, mobile phase containing THF (tetra hydrofuran) are known to be susceptible to oxidation, therefore, the mobile phase should be prepared daily with fresh THF. Some buffered mobile phases cause problems for example, phosphate and acetate provide good media for microbial growth. Sodium oxide (0.1%) is often added to the mobile phase buffer to inhibit such growth, adding more than 5% of organic solvent is also effective. Long term column stability is critical for method ruggedness. Even the best HPLC column will eventually degrade and lose its initial performance, often as a function of the number of samples injected. System suitability System suitability experiments can be defined as tests to ensure that the method can generate results of acceptable accuracy and precision. The requirements for system suitability are usually developed after method development and validation have been completed. The criteria selected will be based on the actual performance of the method as determined during its validation. For example, if sample retention times forms part of the system suitability criteria, their variation (SD) during validation can be determined, system suitability might then require that retention times fall within a  ±3 SD range during routine performance of the method. The USP (2000) defines parameters that can be used to determine system suitability prior to analysis. These parameters include plate number (N), tailing factor, k and / or a, resolution (Rs) and relative standard deviation (RSD) of peak height or peak area for respective injections. The RSD of peak height or area of five injections of standard solution is normally accepted as one of the standard criteria. For an assay method of a major component, the RSD should typically be less than 1% for these five respective injections. The plate number and / or tailing factor are used if the run contains only one peak. For chromatographic separations with more than one peak, such as an internal standard assay or an impurity method, expected to contain many peaks, some measure of separations such as Rs is recommended. Reproducibility of tR or k value for a specific compound also defines system performance. The column performance can be defined in terms of column plate number ‘N’ is defined by N = 5.54 (tR / W ½)2 Where ‘tR’ is the retention time of the peak and ‘W ½Ã¢â‚¬â„¢ is the width of the peak at half peak height. The resolution of two adjacent peaks can be calculated by using the formula Rs = 1.18 (t2-t1) / W0.5.1 +W0.5.2 Where ‘t1’ and ‘t2’ are retention times of the adjacent peaks and W0.5.1 and W0.5.2 are the width of the peaks at half height. Rs = 2.0 or greater is a desirable target for method development. The retention factor k is given by the equation. k = (tR – t0) / t0 where ‘tR’ is the band retention time and t0 is the column dead time. The peak symmetry can be represented in terms of peak asymmetry factor and peak tailing factor, which can be calculated by using the following formula. Peak asymmetry factor = B /A Where ‘B’ is the distance at 50% peak height between leading edge to the perpendicular drawn from the peak maxima and ‘A’ is the width of the peak at half height. According to USP (2000) peak tailing factor can be calculated by using the formula T = W0.05 / 2f Where â€Å"W0.05† is the width of the peak at 5% height and â€Å"f† is the distance from the peak maximum to the leading edge of the peak, the distance being measured at a point 50% of the peak height from the base line. High Performance Liquid Chromatography (HPLC) 214 High Performance Liquid Chromatography (HPLC) 214 Introduction High performance liquid chromatography 214 is the most widely used of all of the analytical separation techniques. The reasons for the popularity of the method is its sensitivity, ready adaptability to accurate quantitative determinations, suitability for separating non-volatile species or thermally fragile ones, wide spread applicability to substance that are of prime interest to industry, many fields of science and the public. The applications of chromatography have grown explosively in the last fifty years owing not only to the development of several new types of chromatographic techniques but also to the growing need by scientist for better methods for characterizing complex mixtures. General methodology for the development of new HPLC methods 215-228 HPLC method development follows the series of steps summarized below. Information on sample, objective of separation. Need for special HPLC procedure, sample pretreatment etc. Choice of detector and detector settings. Choosing LC method, preliminary run, estimation of best separation conditions. Optimization of separation conditions. Check for problems or requirement for special procedure. a) Recovery of purified material   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   b) Quantitative calibration  Ã‚  Ã‚  Ã‚  Ã‚   c) Qualitative method Validate method for routine laboratory use. A good method development strategy should require only as many experimental runs as are necessary to achieve the desired final result. Finally, method development should be simple as possible, yet it should allow the use of sophisticated tools such as computer modeling if these are available. Before the beginning of method development, it is necessary to review what is known about the sample in order to define the goals of separation. The kinds of sample related information that can be important are summarized in Table-7.1. Table-8.1 Important information concerning sample composition and properties Number   of compounds present in the sample Chemical structures of components Molecular weights of compounds PKa values of compounds UV spectra of compounds Concentration range of various compounds in samples of interest Sample solubility   Ã‚   The chemical composition of the sample can provide valuable clues for the best choice of initial conditions for an HPLC separation. Objectives of separation The objectives of HPLC separation need to be specified clearly include. The use of HPLC to isolate purified sample components for spectral identification or quantitative analysis. It may be necessary to separate all degradants or impurities from a product for reliable content assay. In quantitative analysis, the required levels of accuracy and precision should be known (a precision of  ± 1 to 2% is usually achievable). Whether a single HPLC procedure is sufficient for raw material or one or more formulations and / or different procedures are desired for the analysis of formulations? When the number of samples for analysis at one time is greater than 10, a run time of less than 20 min. will be oftenly important. Knowledge on the desired HPLC equipment, experience and academic training the operators have. Sample pretreatment and detection Samples for analysis come in various forms such as: Solutions ready for injections. Solutions that require dilution, buffering, addition of an internal standard or other volumetric manipulation. Solids that must first be dissolved or extracted. Samples that require pretreatment to remove interference and/or protect the column or equipment from damage. Most samples for HPLC analysis require weighing and / or volumetric dilution before injection. Best results are often obtained when the composition of the sample solvent is close to that of the mobile phase since this minimizes baseline upset and other problems. Some samples require a partial separation ( pretreatment) prior to HPLC, because of need to remove interference, concentrate sample analytes or eliminate â€Å"column killer†. In many cases the development of an adequate sample pretreatment can be challenging than achieving a good HPLC separation. The detector selected should sense all sample components of interest. Variable-wavelength ultraviolet (UV) detectors normally are the first choice, because of their convenience and applicability for most samples. For this reason information on the UV spectra can be an important aid for method development. When the UV response of the sample is inadequate, other detectors are available (flourescence, electrochemical, PDA etc.) or the sample can be derivatized for enhanced detection. Developing the method for the separation Selecting an HPLC method and initial conditions If HPLC is chosen for the separation, the next step is to classify the sample as regular or special. Regular samples means typical mixtures of small molecules (    Table-8.2 Handling of special sample Sample Requirements Inorganic ions Detection is primary problems; use ion chromatography Isomers Some isomers can be separated by reversed-phase HPLC and are then classified as regular samples; better separations of isomers are obtainable using either (1) normal-phase HPLC or (2) reversed-phase separations with cyclodextrin-silica columns. Enantiomers These compounds require â€Å"chiral† conditions for their separations. Biological Several factors make samples or this kind â€Å"special†; molecular conformation, polar functionality and a wide range of hydrophobicity. Macromolecules â€Å"Big† molecules require column packing with large pores  Ã‚  (>> 10-nm diameters); in addition, biological molecules require special conditions as noted above. Table-8.3 Preferred experimental conditions for the initial HPLC separation Separation variable Preferred initial choice Column Dimensions (length, ID) 15 x 0.46 cm Particle size 5 mma Stationary phase C8 or C18 Mobile phase Solvent A and B Buffer-acetonitrile % B 80-100%b Buffer (compound, pH, concentration) 25mM potassium phosphate 2.0 Additives (e.g., amine modifiers, ion pair reagents) Do not use initially Flow rate 1.5–2.0 ml/min Temperature 35-45 ºC Sample Size Volumed >25 mL Weightd B : Polar solvent  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   a 3.5 mm particles are an alternative using a 7.5 cm column b For an initial isocratic run; an initial gradient run is preferred. c No buffer required for neutral samples; for pH d Smaller values required for smaller-volume columns (e.g., 7.50.46-cm, 3.5-mm column). Table-8.4 Physical properties of silica supports for some C 18 columns Column (mL/mL) Pore diameter (nm) Surface area (m2/g) Percent Porosity Hypersil ODS 12 170 57 LiChrosorb C18 10 355 71 Novapak C18 6 N/Aa N/Aa Nucleosil C18 10 350 69` Symmetry C18 10 335 66 Zorbax ODS 6 300 55 Zorbax Rx, SB, XDB 8 180 50 a N/A : Not available On the basis of the initial exploratory run isocratic or gradient elution can be selected as most suitable. If typical reversed-phase conditions provide insufficient sample retention, suggesting the use of either ion pair on normal phase HPLC. Alternatively, the sample may be strongly retained with 100% acetonitrile as mobile phase, suggesting the use of non-aqueous reversed-phase (NARP) chromatography or normal phase HPLC. Some characteristics of reversed-phase and other HPLC methods are summarized below. Table-8.5 Characteristics of primary HPLC methods Method / description/ columns Preferred method Reversed-phase HPLC Uses water – organic mobile phase Columns: C18 (ODS), C8, phenyl, trimethylsilyl (TMS), Cyano First choice for most samples, especially neutral or non-ionisable compounds that dissolve in water-organic mixtures Ion-pair HPLC Uses water-organic mobile phase a buffer to control pH and an ion pair reagent. Column : C18, C8, cyano. Acceptable choice for ionic or ionizable compounds, especially bases or cations. Normal phase HPLC Uses mixtures of organic solvents as mobile phase Columns: Cyano, diol, amino and silica. Good second choice when reversed-phase or ion-pair HPLC is ineffective, first choice for lipophilic samples that do not dissolve well in water-organic mixtures, first choice for mixtures of isomers and for preparative-scale HPLC (silica best) Getting started on method development One approach is to use an isocratic mobile phase of some average solvent strength (e.g., 50%) organic solvent. A better alternative is to use a very strong mobile phase with (80-100% B), then reduce %B as necessary. The initial separation with 100%B results in rapid elution of the entire sample, but few groups will separate. Decreasing solvent strength shows the rapid separation of all components with a much longer run time, with a broadening of later bands and reduced detection sensitivity. Improving the separation and repeatable separation Generally the chromatographers will consider several aspects of the separation, as summarized in Table-8.6. Table-8.6 Objectives of separation in HPLC method development Objectivesa Comment Resolution Precise and rugged quantitative analysis requires that Rs be greater than 1.5. Separation time Quantitation   Ã‚ £ 2% (1 SD) for assays;  £ 5% for less-demanding analysis;  £15% for trace analysis. Pressure Peak height Narrow peaks are desirable for large signal / noise ratios Solvent consumption   Minimum mobile-phase use per run is desirable. a Roughly in order of decreasing importance but may vary with analysis requirements. Separation or resolution is a primary requirement in quantitative HPLC. The resolution (Rs) value should be maximum (Rs>1.5) favours maximum precision. Resolution usually degrades during the life of the column and can vary from day to day with minor fluctuations in separation conditions. Therefore, values of Rs = 2 or greater should be the goal during method development for simple mixtures. Such resolution will favour both improved assay precision and greater method ruggedness. Some HPLC assays do not require base line separation of the compounds of interest (qualitative analysis). In such cases only enough separation of individual components is required to provide characteristic retention times for peak identification. The time required for a separation (run time = retention time for base band) should be as short as possible and the total time spent on method development is reasonable (runtimes 5 to 10 minutes are desirable). Conditions for the final HPLC method should be selected so that the operating pressure with a new column does not exceed 170 bar (2500 psi) and upper pressure limit below 2000 psi is desirable. There are two reasons for that pressure limit, despite the fact that most HPLC equipment can be operated at much higher pressures. First, during the life of a column, the back pressure may rise by a factor of as much as 2 due to the gradual plugging of the column by particular matter. Second, at lower pressures When dealing with more challenging samples or if the goals of separation are particularly stringent, a large number of method development runs may be required to achieve acceptable separation. Repeatable separation As the experimental runs described above are being carried out, it is important to confirm that each chromatogram can be repeated. When changing conditions (mobile phase, column, and temperature) between method development experiments, enough time must elapse for the column to come into equilibrium with a new mobile phase and temperature. Usually column equilibration is achieved after passage of 10 to 20 column volumes of the new mobile phase through the column. However, this should be confirmed by carrying out a repeat experiment under the same conditions. When constant retention times are observed in two such back-to-back repeat experiments ( ± 0.5% or better), it can be assumed that the column is equilibrated and the experiments are repeatable. Completing the HPLC method development The final procedure should meet all the objectives that were defined at the beginning of method development. The method should also be robust in routine operation and usable by all laboratories and personnel for which it is intended. Quantitation and method validation One of the strengths of HPLC is that is an excellent quantitative analytical technique. HPLC can be used for the quantitation of the primary or major component of a sample (including pure samples) for mixture of many compounds at intermediate concentrations and for the assessment of trace impurity concentrations in matrix. Method validation, according to the United States Pharmacopoeia (USP), is performed to ensure that an analytical methodology is accurate, specific, reproducible and rugged over the specified range that an analyte will be analysed. Method validation provides an assurance of reliability during normal use and is sometimes described as the process of providing documented evidence that the method does what it is intended to do. According to USP, the method validation involves eight steps as given below. Precision Accuracy Limit of detection Limit of quantitation Specificity Linearity and range Ruggedness Robustness Precision and accuracy: Already discussed in chapter-1. Linearity The linearity of the method is a measure of how well a calibration plot of response v/s concentration approximates a straight line, or how well the data fit to the linear equation. Y = aX + b Where ‘Y’ is the response, ‘X’ is the concentration, ‘a’ is the slope and ‘b’ is the intercept of a line fit to the data. Ideally, a linear relationship is preferred (b = 0) because it is more precise, easier for calculations and can be defined with fewer standards. Also, UV detector response for a dilute sample is expected to follow Beer’s law and be linear. Therefore, a linear calibration gives evidence that the system is performing properly throughout the concentration range of interest. Generally in HPLC, if we are using internal standard, then the linearity plot is to be drawn by taking concentration of the analyte on x-axis and the ratio of area under the curve (AUC) of analyte to AUC of internal standard (IS) on y-axis. The resulting plot slope, intercept and correlation coefficient provide the desired information on linearity. A linearity correlation coefficient above 0.999 is acceptable for most methods. Limit of detection (LOD) The limit of detection (LOD) is the smallest concentration that can be detected reliably. The LOD represents the concentration of analyte that would yield a signal-to-noise (S/N) ratio of 3. Limit of quantitation (LOQ) The LOQ is the concentration that can be quantitated reliably with a specified level of accuracy and precision. The LOQ represents the concentration of analyte that would yield a signal-to-noise ratio of 10. LOD and LOQ can be determined by using the following expressions. LOD  Ã‚  Ã‚   =  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   3 X N / B LOQ  Ã‚  Ã‚   =  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   10 X N / B Where N is the noise estimate, is the standard deviation of the peak area ratio of analyte to IS (5 injections) of the drugs. B is the slope of the corresponding calibration curve. The LOD and LOQ values determined during method validation are affected by the separation conditions, columns, reagents and especially instrumentation and data systems. Ruggedness Method ruggedness is defined as the reproducibility of results when the method is performed under actual use conditions. This includes different analysts, laboratories, columns, instruments, sources, chemicals, solvents etc. method ruggedness may not be known when a method is first developed, but insight is obtained during subsequent use of that method. Robustness The concept of robustness of an analytical procedure has been defined by the ICH as â€Å" a measure of its capacity to remain unaffected by small, but deliberate variations in method parameters†. The robustness of a method is the ability to remain unaffected by small changes in parameters such as pH of the mobile phase, temperature, percentage of organic solvent and buffer concentration etc. to determine robustness of the method experimental conditions were purposely altered and chromatographic characteristics were evaluated. To study the pH effect on the retention (K1) of the drug, buffer pH is to be changed by 0.2 units. At certain point, retention will increase at any pH above and below of the pH unit. The effect of temperature on the retention characteristics (K1) of the drug is to be studied by changing the temperature in steps 2 ºC from room temperature to 80 ºC and see the effect of temperature on the resolution and peak shape. Effect of percentage organic strength on retention is to be studied by varying the percentage of organic solvents like acetonitrile, methanol etc. from 0 to 2% while the other mobile phase contents are held constant and observe the K1. At certain point decreases in K1 observed with increase in the level of organic solvent. Effect of buffer concentration should be checked at three concentration levels i.e. 0.025 M, 0.05 M and 0.1 M and observe retention time and resolution. Stability To generate reproducible and reliable results, the samples, standards and reagents used for the HPLC method must be stable for a reasonable time (e.g., One day, one week, one month, depending on the need). For example, the analysis of even a single sample may require 10 or more chromatographic runs to determine system suitability, including standard concentrations to create a working analytical curve and duplicate or triplicate injections of the sample to be assayed. Therefore, a few hours of standard and sample solution stability can be required even for a short (10 min.) separation. When more than one sample is analyzed, automated, over night runs often are performed for better laboratory efficiency. Typically, 24 hours stability is desired for all solutions and reagents that need to be prepared for each analysis. Mobile phases should be chosen to avoid stability problems, especially the use of amine additives or specific solvents. For example, mobile phase containing THF (tetra hydrofuran) are known to be susceptible to oxidation, therefore, the mobile phase should be prepared daily with fresh THF. Some buffered mobile phases cause problems for example, phosphate and acetate provide good media for microbial growth. Sodium oxide (0.1%) is often added to the mobile phase buffer to inhibit such growth, adding more than 5% of organic solvent is also effective. Long term column stability is critical for method ruggedness. Even the best HPLC column will eventually degrade and lose its initial performance, often as a function of the number of samples injected. System suitability System suitability experiments can be defined as tests to ensure that the method can generate results of acceptable accuracy and precision. The requirements for system suitability are usually developed after method development and validation have been completed. The criteria selected will be based on the actual performance of the method as determined during its validation. For example, if sample retention times forms part of the system suitability criteria, their variation (SD) during validation can be determined, system suitability might then require that retention times fall within a  ±3 SD range during routine performance of the method. The USP (2000) defines parameters that can be used to determine system suitability prior to analysis. These parameters include plate number (N), tailing factor, k and / or a, resolution (Rs) and relative standard deviation (RSD) of peak height or peak area for respective injections. The RSD of peak height or area of five injections of standard solution is normally accepted as one of the standard criteria. For an assay method of a major component, the RSD should typically be less than 1% for these five respective injections. The plate number and / or tailing factor are used if the run contains only one peak. For chromatographic separations with more than one peak, such as an internal standard assay or an impurity method, expected to contain many peaks, some measure of separations such as Rs is recommended. Reproducibility of tR or k value for a specific compound also defines system performance. The column performance can be defined in terms of column plate number ‘N’ is defined by N = 5.54 (tR / W ½)2 Where ‘tR’ is the retention time of the peak and ‘W ½Ã¢â‚¬â„¢ is the width of the peak at half peak height. The resolution of two adjacent peaks can be calculated by using the formula Rs = 1.18 (t2-t1) / W0.5.1 +W0.5.2 Where ‘t1’ and ‘t2’ are retention times of the adjacent peaks and W0.5.1 and W0.5.2 are the width of the peaks at half height. Rs = 2.0 or greater is a desirable target for method development. The retention factor k is given by the equation. k = (tR – t0) / t0 where ‘tR’ is the band retention time and t0 is the column dead time. The peak symmetry can be represented in terms of peak asymmetry factor and peak tailing factor, which can be calculated by using the following formula. Peak asymmetry factor = B /A Where ‘B’ is the distance at 50% peak height between leading edge to the perpendicular drawn from the peak maxima and ‘A’ is the width of the peak at half height. According to USP (2000) peak tailing factor can be calculated by using the formula T = W0.05 / 2f Where â€Å"W0.05† is the width of the peak at 5% height and â€Å"f† is the distance from the peak maximum to the leading edge of the peak, the distance being measured at a point 50% of the peak height from the base line.

How does the writer create tension and suspense in The Red Room? :: Free Essay Writer

How does the writer create tension and suspense in The Red Room? The writer is able to create tension and suspense through various ways in the short story ‘The Red Room’. The opening sentence in the story immediately mentions the supernatural, which immediately tells us that this is a gothic story. The first sentence is dialogue, but we do not know who is speaking. This creates tension as it is withholding information. This is the main technique used to create both tension and suspense through out this story. Throughout the whole story we are not given any names of the character, but are distinguished by a certain phrase ‘the man with a withered arm’ shows us that each of the characters mentioned in this story has a negative description. The negative description and the withholding information build up tension as we want to know more about these characters and who they are. Using negative words make out that the characters are evil or decrepit. The words used to describe these characters are withered, old decayed and pale. We are also not given a name of the narrator or what business he has at the castle. All we know is that he is sceptical about the ghosts that these people are telling him about. ‘That it will take a very tangible ghost to frighten me’, shows a conflict between the superstitious and the sceptical. This builds up tension as we know that in most gothic stories, the sceptical are usually the ones to get punished. The narrator is mocking these other characters, which builds suspense as we know that in the end it will be he that will be hurt. Another way in which the writer builds up tension and suspense is by writing the story in first person. This makes us feel emotionally drawn to the character. We feel what the narrator feels, and we only know what the narrator knows. Using first person also allows us to trust the narrator or to empathise with the character. The use of imagery or personification increases the suspense in the story, ‘Shadows cower’ is a very descriptive way of showing how frightening the mansion is. It sounds as if the shadows which are linked to darkness themselves are afraid of a greater evil. We wonder what this great evil could be that makes evil itself tremble. Another personification used is ‘candles writhing’. Candles are usually associated to gothic stories, as it is only small source of light within a vast darkness of the room. These personifications and imagery brings the house to life as it makes you feel and see things much

Technology - Digital Video and Copyright Fair Use Essay -- Exploratory

Digital Video and Copyright Fair Use Abstract: Video is one of the most compelling forms of communication of this time. Over the course of the past few years, the gradual but sure drift from analog to digital in video technology has not only improved the abilities of visual communication media to distribute data, but has also improved their abilities to manipulate the data that they distribute. Digital video technology has advanced to the extent that still image manipulation has been usurped by more powerful technological developments that allow elements of a video image to be manipulated in real-time. That is, objects or persons in a video image can be edited out or edited in while the image is in broadcast without the slightest glitch to suggest that some change has occurred; everything would look â€Å"real.† The advantages that this technology opens for visual media are extensive. Similar to some technologies, however, it opens up an exploitive edge. Pixels are plastic (can be changed) and using them to distort or mani pulate reality is an opportunity open to all users of video manipulation tools. The ethics of such uses and the social considerations of how copyright laws would deal with a technology which manipulates digital works of authorship, works to which copyright automatically attaches, are issues worth considering. This paper explores the possible and actual, reputable and less reputable uses of this technology in an attempt to stimulate discussions about how â€Å"well-intended† technologies can be utilized by users in unethical and harmful ways. The paper also attempts to see where possible infringements of copyright’s fair use doctrine has occurred or could possibly occur through use of this technology. A n... ...pinions. Despite the many issues connected to this technology however, the advantages it offers surpass any disadvantages seen thus far. References 1. Amato, Ivan. Lying with Pixels, Technology Review, Cambridge, Jul/Aug 2000. p.61. 2. See reference 1 above. 3. See reference 1, p.62. 4. See reference 3 above. 5. Royal Philips Electronics, Imaging : its digital future, Briefing, Volume 3, Issue 2, article no. 19. 6. See reference 1, p.64. 7. See reference 1 p. 65. 8. Samuelson, Pamela. Copyright’s fair use doctrine and digital data, Association for Computing Machinery., Communications of the ACM; vol. 37, Issue 1; New York, 1994. p. 22. 9. See reference 8, p.23. Additional:- Samuelson, Pamela. Copyright and Digital Libraries. (class material)http://web5.computer-select.com/csweb/session/329/331/ (Article - Free Video Hosting)

Navy Chief Petty Officer Medal of Honor Recipients

The Chief Petty Officer is a rank in the U.S. Navy just above the rank of the Petty Officer First Class. They serve both as leaders and technical experts.   Promotion as a Chief Petty Officer requires superior evaluation and time in service. The Navy Medal of Honor is America’s oldest and still continuing award. The Medal of Honor is the supreme award in the United States of America for bravery in wars.   Any member of the Armed Services of the United States who performs exceptionally in his field of warfare during martial operations risking his life to protect the interests of the country is awarded the Medal of Honor. Since everyone in the Armed Services has values of bravery and selflessness, the recommendation for this award is made with the greatest care and consideration. When the Medal was initially awarded during the Civil Wars, it was the only medal for bravery in wars; but during the Spanish American War, it became the highest honor, with many other medals being given for valor in wars. Apart from the respect the Medal entails, the recipients have many other privileges like increased monetary benefits, wearing their uniforms wherever they choose to, and attending Presidential inaugurations. Even the children of the recipients of the Medal of Honor enjoy privileges. If they are qualified and desire to attend the U.S. military academies, they can do so without any restrictions of quotas. So far, more that 3400 Medal of Honor awards have been given. Getting the prestigious Medal would be the proudest moment of any serviceman, and John Finn had  the taste of it when it was placed around his neck in recognition for his valor in the Second World War. Born in Los Angeles, California, on July 23, 1909, he enlisted in the Navy in 1926 and served as a Chief Petty Officer. John Finn was awarded the prestigious Medal of Honor for his conspicuous heroism and gallantry while at the Naval Air Station Kahoehe Bay, Hawaii, during the air raid by Japan, which targeted the facility.   With a machine gun, Chief Finn effectively fired at the enemy planes. Though he received severe wounds, he put up a brave fight and created great havoc to the enemy planes. His action during the attack was indeed amazing. George Brady was yet another proud possessor of the Medal of Honor. He was born on September 7, 1867.   He was a Chief Gunner’s Mate in the U.S. Navy.   George Brady was awarded the Medal of Honor for his exceptional performance in the Spanish American War. George Brady proved a real asset to the U.S. forces. He was on board the torpedo boat Winslow when enemy forces targeted it. The boat was extensively exposed to bombs and suffered great damage. He repaired the steering gear and promptly maintained watertight integrity and thus saved the vessel.   His masterly skills and untiring loyalty to duty was greatly appreciated, and he was awarded the Medal of Honor. Though every serviceman fights for the country risking his life, such events, which depict individual courage and bravery, are the grounds on which a recommendation for the Medal of Honor is made.   The worth of the Medal of Honor is so  great that senior officers and even the President salutes the Medal, thereby the recipient wearing it. References September 30, 2005, Chief Petty Officer Medal of Honor Recipients [Electronic Version] Retrieved on September 11, 2007, from www.history.navy.mil