Premium Essay

Ligand Phamaceuticals

In:

Submitted By bscott23
Words 1007
Pages 5
Describe what you believe is implied by the term “engagement risk.” What are the key factors likely considered by Deloitte and other audit firms when assessing engagement risk? How, if at all, are auditors’ professional responsibilities affected when a client proposes a higher than normal degree of engagement risk?
I believe that the term “engagement risk” implies that inherent client-specific risks face an auditor throughout the course of an audit, thus creating a risk that the auditor will be unable to successfully assess and manage these risks in the performance of the engagement and properly issue an appropriate opinion. The auditor must understand these client-specific risks, which include, but are not limited to, significant events that affect the operations of the client, business risks facing the client, high-risk areas that require complex or subjective accounting treatments, and timely completion of the audit. (Louwers 112) When a client proposes a higher than normal degree of engagement risk, the focus on the auditors’ professional responsibilities becomes even more imperative, as it is critical that the auditor perform at the highest level to provide the greatest possible assurance that the financial statements are presented fairly, in all material respects. What quality control mechanisms should major accounting firms have in place to ensure that audit partners have the proper training and experience to supervise audit engagements? In any major accounting firm, ensuring that audit partners are qualified to supervise and audit engagement begins at the “top” of the organization and should be expressed through the actions of the firm. Partners should always be promoted and assigned to engagements based on their experience, training, and overall qualifications; never should promotions or assignment be based on anything other than absolute

Similar Documents

Free Essay

Preparation of Bis (Acetylacetonato)Copper (Ii)

...coordination complexes. In this experiment, the metal use is copper (II) ion which is crystal blue in colour when it is copper(II)nitrate. All metal ions in solution can react well with water. The water molecules can also be weakly bonded or more strongly as a ligand to form a complex ion, and these can also present in solid ‘hydrated’ salts of crystallization. For example, copper (II) nitrate (Cu(NO3)2∙3H2O) A complex ion has a metal ion at its center with a number of other molecules or ions surrounding it. These can be considered to be attached to the central ion by co-ordinate (dative covalent) bonds. The molecules or ions surrounding the central metal ion are called ligands. Simple ligands include water, ammonia and chloride ions. All ligands are lone pair donors. In other words, all ligands function as Lewis Bases. A base is an electron pair donor and an acid is an electron pair acceptor. Ligands like water, can donate a pair of non-bonding electrons(lone pair) intro a vacant orbital of a central metal ion and so dative covalent(co-ordinate) bonds hold a complex together. The central metal ion with vacant bonding orbitals can act as a Lewis acid. Ligands act as Lewis bases by electron pair donation to form the metal-ligand bond. Apparatus : filter paper , Buchner funnel, adapter, suction filtration flask, spatula, graduated cylinder, watch glass, glass rod, pipette Chemicals : water, copper (II) nitrate (Cu(NO3)2∙3H2O), 1:1ammonia solution, acetyl acetone Procedure :...

Words: 1374 - Pages: 6

Free Essay

Something

...Hardness Determination for Water Samples* Purpose To introduce the concept of complex formation and stability and to illustrate the analytical application of this concept to the measurement of hardness in water. To determine the total hardness for water and test for Ca and Mg solutions and unknown samples. Introduction Hardness of water is a property caused by the presence of polyvalent metal cations, primarily Ca2+ and Mg2+ in natural waters. Hardness is undesirable in a water supply because it results in scale formation and in soap wastage (Sample Lab, Fiu). If one ever has gone to a place where ground water is abundant and is used for drinking and cooking, one can see that the pots have a white mark done to the long exposure to the metals that these water contains, or the shampoo doesn’t produce bubbles. Chelation process is usually the one used most frequently to measure water hardness. The metal ions in this water may have electrons that can be shared in pairs with a donor to form a coordination bond. If a molecule or ion has more than one "free" electron pair which can be shared with a metal ion or similar species, it is called a chelating agent. The complex is termed a chelate. The chelating reagent that we will be using in this lab is EDTA (ethylene-diamine-tetra-acetic acid ). This reagent is the most commonly used for this purpose. As the name inplies, EDTA is a an acid, a tetraprotic one. In the completely deprotonated form, EDTA can form coordination...

Words: 760 - Pages: 4

Free Essay

Miss

...shift of HINT1 if the ligands interact with the protein. HINT1 gene is associated with schizophrenia and bipolar disorders, and therefore the binding ligand might be a potential drug target for mental disorders. Through the understanding of interaction increases the identification for drug design. Two ligands, GMP and 5-aminoimidazole-4-carboxamide-ribonucleoside (AICAR) are used in the practical. GMP is a well-known binding ligand to HINT1, and it will be a validation for determination of AICAR phosphate and AICAR. AICAR is known as a nucleoside mimetic and a potential candidate. The NMR samples for ligand titration contain 0.2 mM 15N labelled, HINT1, 50 mM sodium phosphate, 50 mM NaCl, pH 7.3, in 90% H2O and 10% D2O. The HINT1-ligand reaction occurs by titrating 50 mMsolution for GMP or 20 mMfor AICAR to a 0.2 mM HINT1, respectively. 1H–15N two dimensional (2D) heteronuclear single quantum coherence (HSQC) spectra can be obtained to assess the structural change of HINT1. NMR spectra were recorded at 25℃, and 1H–15N HSQC spectra were recorded on a Bruker 600 using 1024 points and 128 increments. The software programmes named NMRPipe and NMRDraw are responsible for analysis. The results of saturation-transfer difference (STD) NMR are shown in figure 1. Section A represents the STD data for GMP as well as two other ligands AICAR phosphate (B) and AICAR (C). The presence of the residual NMR signal is observed in the STD experiment, namely the ligands might interact with HINT1...

Words: 783 - Pages: 4

Free Essay

Preparation of Bis(Acetylacetonato)Copper(Ii) Complex

...bis(acetyacetonato) copper(II) complexTheory/Background:All metal ions in solution are 'associated' with water. The water molecules can also beweakly bonded or more strongly as a ligand to form a complex ion, and these can also present in solid 'hydrated' salts of crystallization. E.g Copper(II) nitrate (Cu(NO 3 ) 2 .3H 2 O).A complex ion has a metal ion at its centre with a number of other molecules or ionssurrounding it. These can be considered to be attached to the central ion by co-ordinate(dative covalent) bonds. The molecules or ions surrounding the central metal ion arecalled ligands. Simple ligands include water, ammonia, acetyl acetone and chloride ions.Ligand has active lone pairs of electrons in the outer energy level. These are used to formco-ordinate bonds with the metal ion. All ligands are lone pair donors. In other words, allligands function as Lewis bases.Lewis acid-base theory reminders:A base is an electron pair donor and an acid is an electron pair acceptor.Ligands like water, can donate a pair of non-bonding electrons (lone pair) into a vacantorbital of a central metal ion and so dative covalent (co-ordinate) bonds hold a complextogether.The central metal ion with vacant bonding orbitals can act as a Lewis acid.Ligands act as Lewis bases by electron pair donation to form the metal-ligand bond.Bronsted-Lowry acid-base theory reminders (essentially a sub-set of Lewis Theory)A base is a proton acceptor.This is via an electron lone pair on the base (a Lewis base...

Words: 396 - Pages: 2

Free Essay

Electron Transfer Reactions

...outer-sphere processes. Electron transfer reactions play an essential role in many physical, chemical and biological processes. The investigation of the mechanisms of these reactions rests essentially on the systematic investigation of structure-reactivity relationships that results from the geometric rearrangements which accompany the change in oxidation states of the coordination compounds. Although many theories have been proposed, it is no surprise that the more simpler ones such as Marcus theory are the most popular.1 In spite of the great success of the theory of Marcus in interpreting several of these structure-reactivity relations namely in terms of the reaction energy (AG), changes in equilibrium bond lengths (lred-lox) and metal-ligand force constants (fox and fred), several problems remain. ANOMALOUS FEATURES OF ELECTRON TRANSFERS Marcus theory and related approaches emphasize the importance of the reaction energy barrier of the solvent...

Words: 1092 - Pages: 5

Premium Essay

Edta And Edda To Reduce Dylan's Tissues

...Initially, Dylan was treated with EDTA and then DMSA. 1. What are EDTA and DMSA and how might they reduce the high levels of lead in Dylan’s tissues? EDTA ~ Ethylenediaminetetraacetic acid, EDTA is an aminopolycarboxylic acid; a colourless, water-soluble solid, its usefulness comes from its ability to sequester metal ions and act a chelating agent, a hexadenate ligand. Once metal ions are surrounded to the EDTA (1), they remain in solution but become less reactive, “chelation therapy” EDTA was first approved for use in 1953 by the U.S ~ FDA. DMSA ~ Dimercaptosuccinic acid, An organosulphur compound, a meso isomer also used as a chelating agent, its primary use is for the treatment of lead poisoning, again a colourless solid containing two carboxylic acid and two thiol groups, which give a distinct foul odour (5). Established by Chinese scientists in 1957 to be effective in...

Words: 1565 - Pages: 7

Free Essay

Who Cares

...some extent rinse water contain silver thiosulfate complex ions. They are far less toxic than free silver ion, and they become silver sulfide sludge in the sewer pipes or treatment plant. However, the maximum silver concentration in discharge is very often tightly regulated. Silver is also a somewhat precious resource. Therefore, in most large scale processing establishments, exhausted fixer is collected for silver recovery and disposal. Many photographic chemicals use non-biodegradable compounds, such as EDTA, DTPA, NTA and borate. EDTA, DTPA, and NTA are very often used as chelating agents in all processing solutions, particularly in developers and washing aid solutions. EDTA and other polyamine polycarboxylic acids are used as iron ligands in colour bleach solutions. These are relatively nontoxic, and in particular EDTA is approved as a food additive. However, due to poor biodegradability, these chelating agents are found in alarmingly high concentrations in some water sources from which municipal tap water is taken.[7][8] Water containing these chelating agents can leach metal from water treatment equipment as well as pipes. This is becoming an issue in Europe and some parts of the world.[citation needed] Another non-biodegradable compound in common use is surfactant. A common wetting agent for even drying of processed film uses Union Carbide/Dow Triton X-100 or octylphenol ethoxylate. This surfactant is also found to have estrogenic effect and possibly other harms to...

Words: 541 - Pages: 3

Free Essay

Preparation of Silver Carbene Complexes from Imidazolium Salts

...excellent two electron donor ligands towards almost any element in the periodic table. They coordinate strongly to late transition metals and heavy main group elements, but are also known to bind to early transition metals and the lanthanoids. However, there are alternative methods to prepare air- and moisture-stable species that can be used to transfer carbenes to other metals. In particular this involves the preparation of imidazolium salts and reacting it with Ag2O to form robust silver complexes.(1) Discussion: (1) Formation of imidazolinium chlorides from corresponding aniline C2H4Cl2 (l)+ 2C6H7N (l) + C7H16O3 (l) 2C21H25ClN2 Synthesis of (SIPr)AgCl 2SIPr.HCl (l)+ AgO(s) → 2 (SIPr)AgCl(l) + H2O(l) (2) The NHC ligand is significantly more tightly bonded than the phosphine ligand as a consequence of the larger energetic contributions of the σ-donation, π-back-donation. Back-bonding in carbonyl and phosphine metal complexes influence the bond strength. Donation of electrons from the filled π-orbital or lone electron pair orbital of the ligand into an empty orbital of the metal (donor–acceptor bond), together with release (back donation) of electrons from an nd orbital of the metal (which is of π-symmetry with respect to the metal–ligand axis) into the empty π*-antibonding orbital of the ligand. (2) Singlet carbenes are also highly basic and are powerful electron donors. These properties make carbenes exceptionally good ligands for a wide variety of metals...

Words: 382 - Pages: 2

Free Essay

5-Ht Receptor Family

...coupled receptors (GPCRs), whereas 5-HT3 is uniquely ionotropic, (Engleman et al., 2008) (see Fig. 1.) Walstab, J., Rappold, G. and Niesler, B. (2010). 5-HT3 receptors: Role in disease and target of drugs. Pharmacology & Therapeutics, 128(1), pp.146-169. Fig. 1. Schematic of a typical 5-HT3 receptor, showing the cation lumen after the removal of a subunit. Arrows point to reveal the agonistic, competitive, non-competitive antagonists and positive modulators. The orthosteric ligand binding site is magnified to show the binding loops of neighbouring subunits. An arrow also shows the transmembrane (TM) domains of an individual subunit, with TM2 lining the channel pore. A pentemeric receptor consisting of four TM segments to form an intrinsic cation selective, water-filled channel (Barnes et al., 2009). A typical subunit exhibits a large extracellular N-terminus (Iversen, 2009) and a short extracellular C-terminus (Mukerji, Haghighi and Séguéla, 1996). As a member of the cys-loop family of ligand-gated ion channel receptors, 5-HT3 channel opening is a result of the extracellular connection of an agonist to a distinctive binding site on the channel protein. A conformational change occurs resulting in the opening of the central ion pore, where ion...

Words: 1289 - Pages: 6

Free Essay

Crystal Structure of Lymnaeastagnalis Achbp Complexed with the Potent Nachr Antagonist Dhbe Suggests a Unique Mode of Antagonism

...Crystal Structure of Lymnaea stagnalis AChBP Complexed with the Potent nAChR Antagonist DHb E Suggests a Unique Mode of Antagonism Azadeh Shahsavar1, Jette S. Kastrup1, Elsebet Ø. Nielsen2, Jesper L. Kristensen1, Michael Gajhede1, Thomas Balle1*¤ 1 Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark, 2 NeuroSearch A/S, Ballerup, Denmark Abstract Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated ion channels that belong to the Cys-loop receptor superfamily. These receptors are allosteric proteins that exist in different conformational states, including resting (closed), activated (open), and desensitized (closed) states. The acetylcholine binding protein (AChBP) is a structural homologue of the extracellular ligand-binding domain of nAChRs. In previous studies, the degree of the C-loop radial extension of AChBP has been assigned to different conformational states of nAChRs. It has been suggested that a closed C-loop is preferred for the active conformation of nAChRs in complex with agonists whereas an open C-loop reflects an antagonist-bound (closed) state. In this work, we have determined the crystal structure of AChBP from the water snail Lymnaea stagnalis (Ls) in complex with dihydro-b-erythroidine (DHbE), which is a potent competitive antagonist of nAChRs. The structure reveals that binding of DHbE to AChBP imposes closure of the C-loop as agonists, but also a shift perpendicular...

Words: 4870 - Pages: 20