Hard news Essay Example | Topics and Well Written Essays - 1500 words

Hard news - Essay Example â€Å"I use acrylic paints because they are versatile, available in many shades, blend well and can be mixed with glazes or pastes for different effects. As I work fairly quickly, they are more suited to my style,† he says. â€Å"Angony is very quick when he works and he doesn’t like to be interrupted. I think that is why he doesn’t usually like to have people around while he’s ‘in the zone’† says neighbor Sheila Creeley. â€Å"But sometimes you’ll notice the green hat you were wearing or that thing that you were doing in one of his next paintings.† Primitive art recognizes that the underlying elements of human emotions can be deeply expressed through the colors and lines of the work more than the symbols and forms found in the image. By de-emphasizing focus on the image and channeling the emotional experience of the moment, primitive artists attempt to bridge any emotional distance introduced through cultural or social differences of symbol interpretation. This concept is perhaps best expressed by the words of Jean Francois Lyotard in his 1984 book The Postmodern Condition when he describes the process as an attempt â€Å"to make visible that there is something which can be conceived and which can neither be seen nor made visible.† This element is most often referred to as the sublime. For many artists, such as Angony, this sublime element is recaptured to the highest degree through the sense of wonder and imagination typically found through the focus on ‘primitive’ geometric forms. The movement toward primitive art was started by Pablo Picasso. As artists concentrated on the essence of the experience of the art and its creation instead of the symbolic form, they discovered that emotions were generally felt the same universally even when technical elements such as symbols, shapes or colors were understood differently by different cultures. This meant that the

Involvement of the Intracellular Signal Integrating Proteins Calcyon Essay

Involvement of the Intracellular Signal Integrating Proteins Calcyon and Spinophilin - Essay Example Results showed that calcyon and spinophilin transcripts were significantly higher in the thalamus of patients with schizophrenia. They concluded that, as discovered in other research, the dopamine system shows as abnormal in schizophrenia cases, but these abnormalities were due to intracellular integration where dopamine signaling with other neurotransmitter systems was dysfunctional, So it is not only the action of dopamine agonists or antagonists which impact, but the cellular activity which contributes to the illness. This scientific piece of writing encompasses so many areas of medical knowledge that it demands several readings to make sense of each point. However, it is fully detailed and demonstrates how the researchers used a stringent methodology, adhered to ethical and confidential practice and met their objective, as evidenced by the findings. It just seemed to take a long time and a great deal of narrative to produce the relevant information. They were honest as to limitations identified, such as age and antipsychotic drug use, the latter of which might have affected results, though this was considered unlikely.

Intermediate Horsemanship Syllabus Essay Example for Free

Intermediate Horsemanship Syllabus Essay Course Objectives: This course is designed to be a laboratory class giving students maximal opportunity to gain hands-on experience working with horses. This is a continuation of ADSC 2500L (Beginning Horsemanship) and will go into greater detail of advanced concepts regarding riding, training, and handling horses. This class assumes that students have a basic understanding of rider position. This class will focus on going into more detail on rider influence of the horse and training techniques for different disciplines. Prerequisites: ADSC 2500L or a good basic mastery of correct riding position and basic riding skills. Riders should be able to catch, groom, and saddle their horses independently, as well as mount from the ground unassisted. Riders should also be able to ride comfortably at a walk, trot (jog), or canter (lope) in order to be comfortable performing exercises involved in the class. Physical requirements: This class involves physical activity and inherent risk associated with working with horses. While we do everything possible to ensure safety of students, there is always a risk of being injured while riding. In order to participate in this class, you will be required to sign a waiver releasing UGA of all liability associated with any injury you may sustain while participating in the class. I am not a doctor and cannot tell you what you are medically or physically capable of doing based on pre-existing conditions, physical fitness, etc. If you have concerns as to whether you can safely participate, please see a licensed health care physician prior to participating in this class. At the very minimum, students will be required to saddle horses unassisted (requiring you to lift approximately 30 lbs over head) and be able to mount unassisted from the ground. Attire: Long pants and boots with heels are required each day in order to participate. Approved helmets are mandatory but will be provided. All other equipment will be provided. If you choose to bring your own saddle, please do not leave it at the Arena—we cannot be responsible for lost or damaged equipment. Please recognize that you are responsible for ensuring the safety and functionality of any equipment you choose to bring to use. Text: There is no required text for this class. I will often copy chapters from Centered Riding by Sally Swift (copyright 1985) as well as excerpts from related books, magazines, and journals. A list of tentative handouts for each week is provided on the syllabus. Schedule: (This is a tentative list of topics. Topics may be added or deleted as necessary to benefit the course) Week 1 Jan 7-11: Introduction Week 2 Jan 14-18: Basic position, correct use of hands; practice bending, transitions, canter departures; drill team exercises at the walk, trot, and canter â€Å"Basic Horsemanship Required for Training Horses†, â€Å"Half Halt How To†, â€Å"Half Halt† in Centered Riding Week 3 Jan 21-25: Learning collection and developing self carriage in horses, discussion of training aids such as martingales, draw reins, side reins, and types of bits; exercise: barrel patterns to improve turns â€Å"Bitting and Driving†, â€Å"Circles and Turns†, â€Å"Borrow A Trainer-Correct Bends on Curves and Squares†, â€Å"The Perfect Turn, Parts 23† Week 4 Jan 28-Feb 1: Simple lead changes, work on correct bending, movement of hind end and front end of horse; exercises: barrel patterns and serpentines through cones â€Å"Suppling the Horse† Week 5 Feb 4-8: Riding for accuracy developing response time; exercises: continuation of barrel patterns and serpentines as well as pattern work with transitions, straight lines, circles, etc. Week 6 Feb 11-15: Extending and shortening the stride, learning stride control using poles, emphasis on self carriage and pace control â€Å"Walk and the Following Seat†, â€Å"Lengthening Stride†, â€Å"Borrow a Trainer-Extending the lope and slowing back down†, â€Å"†Jarring Jog† Week 7 Feb 18-22: Collection and extension, use of poles, pole courses â€Å"Building Stronger BasicsBAR—Simple Changes on Course† MIDTERM—FEB 20/21—covers handouts thru week 6 Week 8 Feb 25-Mar 1: Controlling the bend and stride of the horse using poles; pole exercises on circle Week 9 Mar 4-8: Flying lead changes â€Å"Flying Change of Lead—Presentation† Week 10 Spring Break—March 11-15 Week 11 Mar 18-22: Counter canter and balance â€Å"Chapter 10—Counter Canter†, â€Å"Confirm that Counter Canter† Week 12 Mar 25-29: Counter canter; patterns incorporating canter, bending, counter canter Week 13 Apr 1-5: Learning lateral movements, moving parts independently â€Å"Lateral Work†, â€Å"Always a Pleasure† Week 14 Apr 8-12: Teaching horses lateral movements and pivots Week 15 Apr 15-19: Trail courses to improve control Week 16 Apr 22-26: Practice day April 29—Last day of class Final Exam: M/W section: Wednesday, May 1, 8:00-11:00 am T/H section: Thursday, May 2, 12:00-3:00 pm Grading: Participation and progress25%* Midterm25% Final25% Final Project25% * will be determined by a % of days in class (i.e. no absences = 100%); lateness or non-participation will count as an absence for the day; participation may at times include riding tests. Absences may be excused for medical or school related activities. In the event of an excused absence, these days will count neither for nor against your attendance grade. ***More than 5 absences (excused or unexcused) will result in a failing grade for the course. Final Project: Video will be taken during different portions of the course. You will write a paper to evaluate your riding. Paper should be a minimum of 2-3 pgs single spaced in length. Papers should include the following: analysis of your riding strengths and weaknesses, analysis of what skills you have improved upon, analysis of your position and effectiveness as a rider including areas which you are strong and areas that you need to improve, specific examples (i.e., people in the class) who exemplify particularly desirable riding skills that should be emulated (e.g., â€Å"Mary is particularly effective at controlling her horse’s pace using little hand movement†Ã¢â‚¬â€perhaps this is due to correct position, stability of seat, etc. These are areas you can expand upon), analysis of the exercises done in class as to their effectiveness in improving your riding skills, other exercises you feel you should be doing to improve your riding techniques.

Sodium Alginate and Polymer Drug Delivery Systems

Sodium Alginate and Polymer Drug Delivery Systems Sodium alginate is a hygroscopic material, although, stable at low humidities and at cool temperatures. Aqueous solutions of sodium alginate are most stable at ph 4-10. Below ph3, alginic acid is precipitated. Sodium alginate solutions are susceptible to microbial spoilage during storage, which may effect on solution viscosity. Subsequent loss of viscosity due to depolarization was observed when sodium alginate was heated above 70Â °c. Preparations containing sodium alginate for external use may be preserved by the addition of 0. 1% chlorocresol, chloroxylenol, or parabens and if the medium is acidic, benzoic acid may be used. Bulk material should be stored in an airtight container in a cool and dry place. Sodium alginate is incompatible with acridine derivatives, crystal violet, phenyl mercuric acetate and nitrate, heavy metals and ethanol in concentrations greater than 5%w/v. Low concentrations of electrolytes cause an increase in viscosity but high electrolyte concentrations causing salting out of sodium alginate; salting out occurs if more than 4% of sodium chloride is present. Sodium alginate is used in variety of oral and pharmaceutical formulations. In tablet formulations, sodium alginate may be used as both a binder and disintegrant. It has also been used as a diluents in capsule formulations and also been used in the preparation of sustained release oral formulations, since it can delay the dissolution of a drug from tablets, capsules and aqueous suspensions. Recently, sodium alginate has been used for the aqueous microencapsulation of drugs in contrast with the more conventional microencapsulation techniques which use organic solvent systems. It has also been used in the formation of nanoparticles. The adhesive nature of hydrogels prepared from sodium alginate has been investigated and the drug release from oral mucosal adhesive tablets based in sodium alginate has been reported. Hydrogel systems containing alginates have also been investigated for delivery of proteins and peptides. Therapeutically sodium alginate has been used in the combination with an h2 receptor antagonist in the management of gastroesophageal reflux and as a haemostatic agent in surgical dressings. Alginate dressings, used to treat exuding wounds often contain significant amounts of sodium alginate as this improves the gelling properties. Sodium alginate is also used in cosmetics and food products at concentrations given in table 4 Safety Sodium alginate is widely used in cosmetics, food products, and pharmaceutical formulations, such as topical products, including wound dressings. It is generally regarded as a nontoxic and non-irritant material, although excessive oral consumption may be harmful. The WHO has not specified an acceptable daily intake for alginic acid and alginate salts as the levels used in foods do not represent a hazard to health. Handling precautions. Sodium alginate may be irritant to eye or respiratory system if inhaled as dust;eye protection, gloves, dust respirator are needed while handling. Sodium alginate should be handled in a well ventilated environment. Related substances The various substances related to sodium alginate include alginic acid, potassium alginate, calcium alginate, propylene glycol alginate. CHITOSAN Chitosan is a derivative of chitin and it is a unique polysaccharide and hydrophilic polymer. Non Proprietary Names BP: Chitosan hydrochloride Ph Eur : Chitosan hydrochloridum Chemistry Preparation The principle derivative of chitin, namely Chitosan (C6H11O4N)n is a unique polysaccharide and hydrophilic polymer which is taken from the chitin, a polysaccharide found in exoskeletons of crustaceans. it is processed by removing the shells from shellfish such as shrimp, lobusters and crabs. The shells are then ground into a pulverous powder. This powder is then deacetylated. This involves boiling chitin in concentrated alkali (50%) for several hours. This will yield chitosan with a degree of acetylation between 20-30%, the most popular commercial form of Chitosan. In such a chitosan, the acetyl groups are uniformly distributed along the polymer chain. This is in contrast with the Chitosan of similar degree of acetylation, but isolated from fungal cell walls in which the acetylresidues are grouped into clusters. Special chemical treatments are required to obtain completely de-acetylated forms of chitosan. CHITIN Functional category It is used as a coating agent; disintegrant; film forming agent; mucoadhesive, tablet binder; viscosity increasing agent etc. Chemical character Chitosan is a cationic polyamine with a high charge density at ph The amino group in chitosan has a pka value of approximately 6. 5, thus chitosan is positively charged and soluble in acidic to neutral solution with a charge density depend on ph and the %da. Numerous studies have demonstrated that the salt form, molecular weight, and degree of deacetylation as well as ph at which chitosan is used all influence how this polymer is utilized in pharmaceutical application. Chitosan is incompatible with strong oxidising agent. Typical properties Chitosan is a cationic polyamine with a high charge density at ph Acidity / alkalinity pH=4-6(1%w/v aqueous solution) Density 1. 35-1. 49g/cm3 Particle size distribution Stability and storage conditions Chitosan is a stable material at room temperature although it is hygroscopic after drying. Chitosan should be stored in a tigjtly closed container in a cool and dry place. Incompatibilities Chitosan is incompatible with strong oxidizing agents. Safety Chitosan is being investigated widely for use as an excipient in oral and other pharmaceutical formulations. It is also used in cosmetics. chitosan is generally regarded as biodegradable, nontoxic and non irritant material. it is biocompatible with both healthy and infected skin. Applications Chitosan is found useful in many fields like sustained drug delivery, components of mucoadhesive dosage forms, rapid release dosage forms, improved peptide delivery, colonic drug delivery systems and use for gene delivery. Chitosan is processed into several pharmaceutical forms including gels, beads, films, microspheres tablets and coatings for liposomes. PROPRANOLOL HYDROCHLORIDE (ÃŽÂ ²-adrenergic blocking agents) Adrenergic nonselective ÃŽÂ ²-receptor antagonist. (antihypertensive, antianginal and antiarrhythmic. ) STRUCTURE Chemical name (ÂÂ ±)-1-isopropylamino-3-(1-naphthyloxy) propan-2-ol hydrochloride Molecular formula C16H21NO2. HCl Molecular weight 295. 8 Description: A white powder, odourless and bitter in taste Solubility: Soluble Soluble 1 in 2 of water and ethanol Slightly soluble in chloroform I . PHARMACOLOGICAL ACTIONS a. Cardiovascular-Propranolol diminishes cardiac output, heart rate, and force of contraction. These effects are useful in the treatment of angina. b. Peripheral vasoconstriction-Blockade of ÃŽÂ ²-receptors prevents ÃŽÂ ²2-mediated vasodilation. The reduction in cardiac output leads to decreased blood pressure. c. Bronchoconstriction-Blocking ÃŽÂ ²2 receptors in the lungs of susceptible patients causes contraction of the bronchiolar smooth muscle. Î’-blockers are thus contradicted in patients with asthma. d. increased Na+ retention-reduced blood pressure causes a decrease in renal perfusion, resulting in an increase in Na+ and plasma volume. in some cases this compensatory response tends to elevate the BP. For these patients, ÃŽÂ ²-blockers are often combined with a diuretic to prevent Na+ retention. II. THERAPEUTIC EFFECTS a. Hypertension-propranolol lowers BP in hypertension by decreasing cardiac output. b. glaucoma-propranolo is effective in diminishing intraocular pressure in glaucoma. c. migraine-propranolol is also effective in reducing migraine episodes by blocking the catecholamine induced vasodilation in the brain vasculature. d. angina pectoris-propranolol decreases the oxygen requirement of heart muscle and therefore effective in reducing the chest pain in angina. e. myocardial infarction-propranolol and other ÃŽÂ ²-blockers have a protective effect on the myocardium. thus, patient who have had one myocardial infarction appear to be protected against a second heart attack by prophylactic use of ÃŽÂ ²-blockers. III. ADVERSE EFFECTS a. broncho constriction-when propranolol is administered to an asthmatic patient, an immediate contraction of the bronchiolar smooth muscle prevents air from entering the lungs. Therefore, propranolol must never be used in treating any individual with obstructive pulmonary disease. b. arrhythmias-treatment with the ÃŽÂ ²-blockers must never be stopped quickly because of the risk of precipitating cardiac arrhythmias. c. disturbances in metabolism- ÃŽÂ ² bloackade leads to decreased glycogenolysis and decreased glucagon secretion. d. drug interaction-drugs that interfere with the metabolism of propranolol, such as cimetidine, furosemide and chlorpromazine may potentiate its antihypertensive effects. conversely those that stimulate is metabolism, such as barbiturates, phenytoin and rifampicin can mitigate its effects. PHARMACOKINETICS Propranolol is well absorbed after oral administration but has low bioavailability due to high first pass metabolism in liver. it is highly bound to plasma proteins. Metabolism of propranolol is dependent on hepatic blood flow. DOSE Oral 10mg BD to 10mg QID (average 40-60mg/day) I. V 2-8mg injected over 10min with with constant monitoring. it is not injected S. C or I. M because of irritant property. MATERIALS NAME OF THE MATERIALS NAME OF THE COMPANY Propranolol hydrochloride Sodium alginate AR Hi-Media biosciences Ltd, Mumbai. Calcium chloride AR S. D Fine chemicals Ltd, Mumbai Barium chloride AR Qualigens Fine Chemicals Ltd, Mumbai Chitosan AR Fluca Biochemicals Ltd, Switzerland. (Viscosity 200-400 mPa. s) Acetic acid EQUIPMENTS USED Name of equipment Name of company UV/Vis Spectrophotometer JASCO V-530 IR Spectrophotometer Jasco-FT-IR 8201 PC Differential scanning calorimeter DSC-60 (Shimadzu, Tokyo, Japan) Optical Microscope and Stage Micrometer Erma. Japan Scanning Electron Microscope JSM 6400 x-ray diffractrometer Bruker AXS D8 Dissolution apparatus Electrolab TDT-08L, USP XXIV Type I Apparatus. Chennai Remi Hi-speed motor Universal motors. Mumbai Digital balance Denver Instruments 18002098899 simi INTRODUCTION MICROENCAPSULATION A process in which very thin coatings of polymeric materials are deposited around particles of solids or droplets of liquid. Different terms for solid particle systems are employed in drug delivery among them pellets, beads, microcapsules, microspheres, millispheres are few. The terminologies of most relevant multiparticulate systems are provided here. Pellets can be defined as Small, free flowing spherical particles manufactured by agglomeration of fine powders or granules of drug substances and excipients using appropriate processing equipment. The size of these particles rae usually between 0. 5 and 1. 5mm. sphericity and intra granular porosity are the two important quality attributes of pellets. The terms spherical granules and beads have been applied interchangeably to pellet system. Microspheres are solids approximately spherical particles ranging in size from 1 to 1000ÂÂ µm. They are made of polymeric, waxy, or other protective materials, that are biodegradable synthetic polymers and modified natural products such as gums, proteins, waxes etc. Microsphere: the enbtrapped substance is dispersed throughout the microsphere matrix. Microcapsule: the entrapped substance is completely surrounded by distinct capsule wall. The similiarities between microsphers and microcapsules are clear and illustrations of these particles are shown in Fig: Encapsulation methods Two major classes of encapsulation methods have evolved, viz chemical and physical. The first class of encapsulation involves polymerisation during the process of preparing the microcapsules. examples of this class are usually known by the name of interfacial polymerisation or in situ polymerisation. The second type involves controlled precipitation of a polymeric solution where in physical changes usually occur. The precipitation and or gelation listed in table cover many techniques. one example isthe precipitation of water soluble polymers such as gelatin with water miscible solvents such as isopropranol. other examples include the precipitation of ethyl cellulose from cyclohexane agin by cooling, and gelation of sodium alginate with aqueous calcium salt solutions. in all cases the objective is to precipitate a performed polymer around the core (sometimes a multi-particulate) to cause encapsulation. Process Coating material Suspended medium Interfacial polymerization Water soluble and insoluble monomers Aqueous/organic solvents Complex coacervation Water soluble polyelectrolyte Water Simple coacervation Hydrophobic polymers Organic solvents Thermal denaturation Proteins Organic solvents Salting out Water-soluble polymer Water Solvent evaporation Hydrophilic or hydrophobic polymer Organic or Water Hot melt Hydrophilic or hydrophobic polymer Aqueous/organic solvents Solvent removal Hydrophilic or hydrophobic polymer Organic solvents Spray drying Hydrophilic or hydrophobic polymer Air, nitrogen Phase separation Hydrophilic or hydrophobic polymer Aqueous/organic solvents POLYMER BASED DRUG DELIVERY SYSTEM There has been growing interest in polymer based bioadhesive drug delivery systems. one of the goals of such systems is to prolong the residence time of a drug carrier in the Gastro Intestinal tract(GIT). The bioadhesive bond can be of a covalent, electrostatic, hydrophobicor hydrogen bond nature. ionic polymers are reported to be more adhesive than neutral polymers, and an increased charge density will also give better adhesion suggesting that the electrostatic interactions are of great importance. except for the oesophagus, the entire GI tract including the stomach is covered with a continous layer of insoluble mucus gel. The mucus gel mainly consists of glycolproteins and due to their content of ester sulphate and sialic acid groups, the mucus layer has an overall strong net negative charge. The mucus layer has been considered as a possible site for bioadhesion and drug delivery by several groups. Natural polymers Recently, the use of natural polymers in the design of drug delivery formulation has received much attention due to their excellent biocompatibility, biodegradability, non toxicity and easy in availability. Polymers as carriers used in drug delivery system The different types of polymers for extended release preparations are given below. Biodegradable polymers The biodegradable polymers comprised of monomers linked to one another through functional groups and have unstable linkages in the backbone. They are biologically degraded or eroded by enzymes or generated by living cells. Natural Albumin, alginate, collagen, starch, chitosan, dextran, casein, gelatine, fibrinogen etc. Synthetic Polyalklyl-cyanoacrylate, poly ethyl cyano acrylate, poly amino acids, poly amides, poly acryl amides etc. Aliphatic polyesters Poly(maleicacid), poly (glycolic acid), poly(hydroxyl butyrate), poly (lactic acid), poly vinyl alcohol(PVA) etc. Non-biodegradable polymers Poly ethylene vinyl acetate(EVA), poly ether urethane(PEU), cellulose acetate, poly vinyl chloride(PVC), ethyl cellulose etc. In recent years a lrge number of biodegradable polymers have been investigated for their potential use as drug delivery systems. among them, sodium alginate and chitosan are very promising and have been widely exploited in pharmaceutical industry for sustained drug release. polysaccharides such as alginic acid, agar, chitin and chitosan have been used to agglomerate drugs for controlled drug delivery systems. Chitosan is a anaturally occurring polysaccharide comprosing of glucosamine and N-Acetyl glucosamine with unique poly cation characteristics. The polycationic nature of chitosan leads to a strong interaction with negatively charged alginate. when alginate is dropped into chitosan solution, the electrostatic interaction of carboxylic groups of alginate with the amino groups of chitosan results in the formation of a membarane on the surface of sodium alginate and improves the stability and drug content. This process has been widely used in the preparation of alginate chitosan membaranes with a solid calcium-alginate gel core. There are many advantages of the chitosan coating, such as the improvement of drug loading and bioadhesive property, as well as the prolonged drug release properties etc. Alginate(ionic, hydrophilic polymer) is a negatively charged polysachharide with high charge density and has been reported to be bioadhesive. among polyanionic polymers, alginate has been widely studied and applied for its possibility to modulate the release according to the properties of its carboxyl groups as well as its biodegradability and absence of its toxicity. alginate is a naturally derived anionic polysaccharide mainly from algae belonging to the family of phaeophyceae. Alginic acid is an algal polysaccharide and a species of poly carboxylic acid. alginate consists of two sugar moieties ÃŽÂ ²-D mannuronic acid and ÃŽÂ ±-L guluronic acid which exist either in blocks or random sequences and their relative proportions determines the biofunctional properties of alginc acid. alginate is known to form complexes with divalent cations, such as Ca2+, Ba2+, and Sr2+ in aqueous solution. depending upon the composition of two sugar residues and sequential distribution within the molecules, the complexes form either precipitates or hydrogels. guluronic acid blocks are known to form a rigid buckled structure, the so called egg box array, in which chelating calcium ions are nestled in the aqueous environment of the ordered gel structure due to the spatial arrangements of guluronic block oxygen atoms of carboxyl and hydroxyl groups. Alginate has been widely used as food additive, a tablet disintegrator or gelation agent, and the mechanism of its gelation have been extensively investigated. when an aqueous solution of sodium alginate(SA) is added dropwise to an aqueous solution of calcium chloride, spherical alginate beads with regular shape and size are produced, since an insoluble calcium alginate matrix is formed by the cation exchange between sodium and calcium ions. alginates are known to form reticulated structure when in contact with calcium chloride ions and this characteristic has been used to produce SR particulate systems for a variety of drugs. GEL FORMATION (GENERAL MECHANISM) A gel in classical colloidal terminology, is defined as a system which owes its characteristic properties to a cross linked network of polymeric chains which form at the gel point. a considerable amount of research has been carried out in recent years to elucidate the nature of the crosslinks and determine the structure of alginate gels. alginate beads can be prepared by extruding a solution of sodium alginate containing the desired drug or protein, as droplets, into a divalent crosslinking solution such as Ca2+, Ba2+, and Sr2+ . monovalent cations do not induce gelation while Ba2+, and Sr2+ ions produce stronger alginate gels than Ca2+. other divalent cations such as Pb2+, Cu2+, Cd2+, CO2+, Ni2+, Zn2+, Mn2+ will also cross link alginate gels but their use is limited due to their toxicity. The gelation and cross linking of the polymers are mainly achieved by the exchange of divalent cations and stacking of these guluronic acids with the divalent cations, and the stacking of these gul uronic groups to form the characteristic egg-box structure shown in fig LARGE BEAD PREPARATION In general, beads greater than 1. 0mm in diameter which can be produced by using a syringe, with a needle or a pipette. sodium alginate solution that contains the solubilised drug or protein is transferred dropwise into a gently agitated divalent cross linking solution. The diameter of the beads formed is dependant on the size of the needle used and the viscosity of the alginate solution . a larger diameter needle and higher viscosity solutions will produce larger diameter beads. The viscosity of SA can also influence the shape of the microbeads produced. The beads become more spherical as the concentration of SA increased. however, in general SA solutions of greater than 5% are difficult to prepare. Since, gelation occurs in an aqueous environment, alginate is a promising material as a food additive, drug formulation and useful even for encapsulation of living cells to protect them from immune responses. utilizing this stable complex formation with divalent cations, alginate gels have been utilized for investigation of cells are considered to be the ultimate system for the pulsatile release of biologically active compounds. Formulation of delivery devices for protein and peptide drugs under aqueous conditions are desirable to avoid the undesirable decrease of bioactivities which may occur when using organic solvents or heat during formulations. since relatively stable alginate gels can be formed in aqueous environments through chelation or complexation, which are promising delivery of matrices for bioactive compounds. It has been suggested that the crosslinks were caused either by ionic bridging of 2 carboxyl groups on adjacent polymer chains via calcium ions or by chelation of single calcium ions by hydroxyl and carboxyl groups on each of a pair of polymer chains. although these bonds may play a role in the gelation mechanism which are not sufficiently energetically favourable to account for the gelation of alginate. it has been shown on thebasis of fibre diffraction data and model-building calculations that the shape of both poly-mannuronic acid segments and the polygulutended, and that these extended ribbons can stack together in sheets. on the basis of these data and the properties of gels it has been suggested that the cooperative association of either polymannuronic acid segments or polyguluronic acid segments are involved in the formation of the crosslinked network of polymer chain. This technique has shown attractive applications in different fields, including cell immobilisation, owing to its mild operating conditions. as the encapsulation method is mild, and done at room temperature in aqueous medium, several sensitive drugs, proteins, living cells, enzymes, spermatozoa etc have been successfully encapsulated through alginate beads. The primary structure of alginate depends on the producing species and for the marine species, seasonal and geographical changes might result in variations in alginates extracted from the same species. The polymer is nown to form a physical gel by hydrogen bonding at low pH(acid gel)and by ionic interactions with polyvalent cations such as calcium, the cation acting as a cross linker between the polymer chains. The viscosity and primary structure of polymer are important features determining it swelling and gelling properties. At neutral pH, sodium alginate is soluble and hydrates to form viscous solutions, but below pH3, alginic acid, water swellable but insoluble, which is rapidly formed. since the hydration characteristics of the polymer and the subsequent physical properties of the hydrated gel layer may critically influence drug release. When CA beads are treated with 0. 1M HCl, alginate gels hydrolysed to lower molecular weight fractions of alginic acid. due to conversion of COO- groups into unionised carboxylic groups, the electrostatic attraction between Ca2+ ions and COO- ions in the egg-box junction almost disappears. moreover, there may occur in ion-exchange between H+ ion(presence in the external HCl solution) and free Ca2+ ions inside the beads. thus a reduced Ca2+ ions concentration within the beads results in a weaker Ca2+ cross linked beads when put in phosphate buffer at pH 6. 8. Therefore, the acid-treated beads are loosely crosslinked structure more soluble alginate as constituent. when such beads are put in the phosphate buffer pH6. 8, the beads swell at a faster rate but do not attain a higher water uptake value due to loosely bound structure of the beads which is unable to retain large amount of water within the beads. moreover, there is possibility of ion-exchange between H+ ions produced due to ion isation of carboxylic groups in the buffer at pH. A group of scientists developed a method of enclosing viable cells, tissues, and other labile biological substances within a semipermeable membrane. preliminary in-vitro studies of several types of microencapsulated cells and tissues(redblood cells, sperm cells, hepatica cells, hepatocytes, pancreatic endocrine tissues, and islets) were described by them. essentially, the process involves suspending the living cells or tissues in sodium alginate solution. The cell or tissue suspension is extruded through a device producing micro-droplets which fall into a calcium chloride solution and form gelled microbeads with the cells or tissues entrapped. These cell containing gel microbeads are next treated with polysine which displaces the surface layer of calcium ions and forms a permanent polysalt shell or membrane. finally, the interior calcium alginate is liquefied, either to stay in or to cum out(depending on molecular weight and size of the starting alginate) of the capsule with a calciu m sequestrant such as buffered citrate solution. Gohel et al ., prepared diclofenac sodium microspeheres by using sodium alginate as a polymer and CaCl2 as a cross linking agent. in this investigation stirring speed, concentration of crosslinking agent and heavy liquid paraffin were studied, on the time required for 80% of drug dissolution. a statistical model with significant interaction terms was derived to predict t80 and drug was released by diffusion of anomalous type. The results of multiple regression analysis and F value statistics revealed that, obtaining of controlled drug release and microspheres were to be prepared using relatively lower stirring speed. Literature reports indicate wide spread use of sodium alginate for achieving sustained release of drugs, targeting gastric mucosa and increasing the bioavailability of drugs because of sodium alginates ability to form a stable and bioadhesive gel with calcium ions. Alginate also has several unique properties that have enabled it to be used as a matrix for the entrapment or delivery of a variety of proteins, macromolecules and cells. USES Of Alginate Beads A relatively inert aqueous environment within the matrix. A mild room temperature encapsulation process free of organic solvent A high gel porosity which allows for high diffusion rate of macromolecules The ability to control this porosity with simple coating procedures. Dissolution and biodegradation of the system under normal physiological conditions. Standard graph for propranolol hydrochloride A stock solution of propranolol hydrochloride was prepared by dissolving 100mg of the drug in 100ml of the phosphate buffer of pH6. 8 to give 1mg/ml solution. ten millilitres of stock solution was diluted to 100ml using phosphate buffer f pH6. 8 to produce 100ÂÂ µg/ml working stock solution. from this working solution, dilutions were made with phosphate buffer of pH6. 8 to produce 10, 20, 30, 40 and 50 ÂÂ µg/ml. The ÃŽÂ » max of the drug was determined by scanning the dilutions between 400 and 200nm using a Shimadzu 1400 UV visible spectrophotometer. At this wavelength, the absorbances of all the other solutions were measured against a blank. Standard curve between concentration and absorbance was plotted. COMPATIBILITY STUDIES One of the requirements for the selection of suitable polymers or carriers for pharmaceutical formulation is its compatibility. Therefore in the present work a compatibility study was done by using Infra Red spectroscopy (IR) and Differential Scanning Calorimetry (DSC) to find out if there is any possible chemical interaction between propranolol hydrochloride and the polymers. DIFFERENTIAL SCANNING CALORIMETRY (DSC) Differential Scanning calorimetric analysis was used to characterize the thermal behaviour of the drug substances. It was performed by using DSC-60(Shimadzu, Tokyo, Japan) calorimeter to study the thermal behaviour of selected formulations. The instrument comprised of calorimeter (DSC60), flow controller (FCL60), thermal analyzer (TA60) and operating software(TA 60). The samples were heated in hermetically sealed aluminium pans under nitrogen flow (30ml/min)at a scanning rate of 5Â °C/min from 24 + 1Â °C to 300Â °C. An empty aluminium pan, sealed in the same way as the sample was used as a reference. SCANNING ELECTRON MICROSCOPY Scanning electron microscopy is used to obtain the surface topographical characterization of beads. SEM photographs of prepared formulations were taken with (Instrument JSM-6390)at different magnification ranging from 30 to 5000x at room temperature. The samples were mounted on double sided adhesive tape that has previously been secured on copper stubs. The acceleratio

Duke Basketball :: essays research papers

There are 12240 students at Duke University, and every year 12 out of those 12240 are put on a mission. The expectations are far above the ground, these 12 men and their coaching staff are called the Duke University Blue Devils basketball team. Year after year their mission is to bring home an NCAA basketball national championship trophy. Three of 84 teams at Duke University have reached their goal by winning a national championship. Duke is one of the nations best known basketball programs. Just eight miles away from Dukes campus, one of their toughest competitors and arch enemy, the University of North Carolina Tar Heels. The Duke ? UNC rivalry is one of the best in sports, they are usually one of the top teams in the nation. Duke is the forth- winningest program in the nation (1799-792). Under Coach Mike Krzyzweski they have become the winnigest program in the country (648-167). Coach K as they call him, has brought all 3 national championships to Durham, North Carolina (1991, 1992, 2001). Duke basketball dates back to when they were Trinity College, the name was later changed in 1923 to Duke University. Trinity never was as high-quality of a team as Duke has been in the last 20 years. Trinity won 48 games in the 65 years of their existence. In Dukes early years the basketball program did not triumph as in recent years. At the time the power sport at Duke was football. In 1949 a change came when a young man named Dick Groat came around, he became the star of the Blue Devil basketball and baseball team. Groat wasn?t recruited to play basketball he was on an athletic scholarship for baseball. None the less, he was elected as an All- American in 1951 and 1952 for his basketball talents. Unfortunately, he was never able to lead either of his teams to a championship. His basketball number (10) was retired, and now hangs on the ceiling of Cameron Indoor Stadium. The 1980?s rolled around and the ?Cameron Crazies? (Duke Basketball fans) felt as if there were no hope for their Blue Devils basketball program, but that?s where they were wrong. Along came what is arguably the greatest coach to step foot on a basketball court, Coach Mike Krzyzewski. Coach K has had unprecedented success at Duke, winning three national championships, and making Duke the powerhouse basketball school that they are today.

The Influence of Greek Thought on Modern Science and Mathematics Essay

The Influence of Greek Thought on Modern Science and Mathematics Parallels can be drawn from Greek thought and compared to today’s modern world views. This comparison also brings forth the influences of the Greek philosophies to the world’s contemporary aspects. More specifically, mathematics and science elicit the relationships of the ancient Greek beliefs and the existing theories and truths. Mathematics, as it relates to the Greek era and the present time, had created and still creates a very new approach to the thoughts of the mechanics of nature. For instance, Pythagoras, the Greek mathematician and philosopher, believed the physical world would be explained by numbers. He used his theory of numbers and applied them to the phenomena of â€Å"harmony.† Using the strings of a lyre, Pythagoras explained his theory through his application of mathematical ratios for the principles of musical intervals. He also believed that there was a â€Å"perfect† number, 3, defines Harmony and the â€Å"All,† while the â€Å"virtue of a number† is 10, for it â€Å"perfects and realizes all things . . . ...

Design Elements in Fashion

Club's new album Champ is pretty damn adorable. I put it on in the car during a rare burst of winter sunlight a few weeks ago and for a few seconds I actually believed it was summer. This is the Ontario band's second full length album, following Elephant Shell in 2008. Lead singer David Monks is only 23 but has produced an incredibly nostalgic album where he describes moments as if they were a lifetime ago, not a few years.For anyone who hasn't heard much of this four-piece Canadian band I would highly recommend them. The song ‘Tessellate' from their first album is one of the loveliest songs I have ever heard, with a youthful outlook on the world and lyrics far beyond their age. David Monks' voice never fails to make me a bit weak at the knees. As well as this they are highly capable of producing catchy, dance around like a frenzied monkey, tracks. The new album is about secrets, growing up, growing apart, double knots, Christmas Cards, favorite foods, favorite colors and endin g your way.The only criticism I can give is that sometimes the lyrics seem too â€Å"teenager†, especially for your Monish educated ears. However sometimes it's nice to reminisce on those moments before everyone cut loose on Schooling. I think Champ will cement their place as one of the most interesting bands to watch at the moment. The album is out September for Australia, and in the words of one highly astute Youth user, â€Å"the man has a voice tuned for a women's vagina†. Amen.