The Correlation Between Staffing Hours and Nursing Home Resident Fall Rate

AbstractHealthcare administrators and researchers have had the burden of determining best practice protocols that minimize falls among older adults living in nursing homes for several years. Several studies have investigated, and identified intrinsic and extrinsic factors that lead to falls among other adults and made recommendations along the lines of their findings. However, researchers are yet to establish the impact of staffing hours on nursing home resident fall rate. The purpose of this study was to determine the correlation if any, between nursing home residents fall rate and the staffing hours they receive daily from certified nursing assistants (CNAs), licensed practical nurses (LPNs), and registered nurses (RNs). This correlational study was based on the systems theory framework. Using multiple regression analysis, data points containing the U.S. averages of nursing homes including rehabilitation services obtained from the CMS database were analyzed. The results of these analyses led to three key findings: (a) insufficient evidence to support the claim of linear correlation between nursing home residents fall rate and CNA staffing hours received per day, (b) there was a linear correlation between nursing home resident fall rate and LPN staffing hours received per day, and (c) there was a linear correlation between nursing home resident fall rate and RN staffing hours received per day. The results of this study may be used by nursing home administrators for positive social change by increasing their staffing of LPNs and RNs to provide the knowledge base required to properly guide the CNAs in providing quality care

A Study of Ligand Coordination at Lanthanide and Group 4 Metal Centers by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry

Reactions of lanthanide amide reagents Ln{N(SiMe3)2}3 (where Ln = Sm, Gd, Ho, or Yb) with amine-bis(phenol) ligands were probed using inert atmosphere matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) (anthracene matrix); the technique rapidly confirms ligand coordination, giving excellent agreement with theoretical isotope patterns for lanthanide(amine-phenolate) fragments. Spectra on isolated lanthanide amine-bis(phenolate) amido complexes are similar to those seen from small scale parallel reactions of metal amides and protonated ligands. Although in all cases molecular ion peaks are not observed, peaks for lanthanide arene complexes, [M + arene]+•, formed in situ, are seen. The lack of molecular ion peak is due to difficulties in ionizing Ln3+ complexes by charge transfer. However, if Nujol is used to disperse the analyte and matrix prior to analysis rather than toluene, arene adducts are not observed. Similar phenol-derived ligands can be reacted with diamagnetic M(NMe2)4 (where M = Ti or Zr), and amine-phenolate complex formation is again confirmed easily by MALDI-TOF MS or LDI-TOF MS (no matrix). These complexes were also characterized by NMR spectroscopy and elemental analysis on isolated samples

Ring-opening polymerization of rac-lactide mediated by tetrametallic lithium and sodium diamino-bis(phenolate) complexes

Lithium and sodium compounds supported by tetradentate amino-bis(phenolato) ligands, [Li2(N2O2BuBuPip)] (1), [Na2(N2O2BuBuPip)] (2) (where [N2O2BuBuPip] = 2,2′-N,N’-homopiperazinyl-bis(2-methylene-4,6-tert-butylphenol), and [Li2(N2O2BuMePip)] (3), [Na2(N2O2BuMePip)] (4) (where [N2O2BuMePip] = 2,2′-N,N’-homopiperazinyl-bis(2-methylene-4-methyl-6-tert-butylphenol) were synthesized and characterized by NMR spectroscopy and MALDI-TOF mass spectrometry. Variable temperature NMR experiments were performed to understand solution-phase dynamics. The solid-state structures of 1 and 4 were determined by X-ray diffraction and reveal tetrametallic species. PGSE NMR spectroscopic data suggests that 1 maintains its aggregated structure in CD2Cl2. The complexes exhibit good activity for controlled ring-opening polymerization of rac-lactide (LA) both solvent free and in solution to yield PLA with low dispersities. Stoichiometric reactions suggest that the formation of PLA may proceed by the typical coordination–insertion mechanism. For example, 7Li NMR experiments show growth of a new resonance when 1 is mixed with 1 equiv. LA and 1H NMR data suggests formation of a Li-alkoxide species upon reaction of 1 with BnOH

Rapid screening of reactions of rare-earth metal complexes through MALDI-TOF mass spectrometry

This thesis describes investigations into the applicability of inert atmosphere: matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) technique for rapid screening of reactions. Complexation reactions of lanthanide amide reagents Ln{N(SiMe₃ )2}₃ (where Ln = Sm, Gd, Ho, Yb, Y or La) with amine-bis(phenol) ligands ([O₂N₂t -Bu,Me H2, [O₂ N₂t -Bu H₂ and [O₂ NN't-Am ]H₂ ) were probed using anthracene as the matrix. This technique rapidly confirmed ligand coordination by showing excellent agreement between the experimental and theoretical isotope patterns. Spectra of isolated lanthanide amine-bis(phenolate) amido complexes are similar to those seen from small scale parallel reactions of metal amides and protonated ligands. Although in all cases molecular ion peaks were not observed, peaks for lanthanide arene complexes, [M + arene] + , formed in situ , were seen. The absence of these molecular ion peaks was due to difficulties in ionizing Ln³⁺ complexes by charge-transfer, and the low coordination number of the lanthanide ions led to laser-assisted arene complex formation. The mechanism of ionization in this study is proposed to involve adduct formation. -- The screening of the hydroamination-cyclization reaction of 5-phenyl-4-pentyne-1-amine potentially catalyzed by various lanthanide amine bis(phenolate) complexes was also studied. Characterization of the reaction mixtures from in situ hydroamination reactions showed changes in mass spectral patterns from the starting materials. Also, significant differences in the spectra of the mixtures containing lanthanide [O₂N₂] and [O₂N₂] complexes were observed. The aminoalkyne substrate is proposed to coordinate to the metal center of the lanthanide bearing [O₂N₂] complexes indicating potential precatalysts for hydroamination of aminoalkynes. These results demonstrate the utility of MALDI-TOF MS as a potential technique for rapid screening of reactions of paramagnetic and extremely moisture-sensitive metal complexes. Aspects of this work have been accepted for publication: Nduka Ikpo, Samantha M. Butt, Kayla L. Collins and Francesca M. Kerton*, Organometallics , om 2008-00453b, accepted for publication August 2008

Synthesis, characterization and reactivity of amine-phenolate complexes towards the preparation of aliphatic polyesters

Biodegradable polymers such as poly(ε-caprolactone) (PCL), polylactide (PLA) and polycarbonate (PC) are important materials m commodity, biomedical and pharmaceutical applications. This is due to their biodegradable, biocompatible and permeable properties, and the fact that the monomers can be sourced from annually renewable feedstocks. One of the most important methods in producing these polymers is ring-opening polymerization (ROP) initiated by metal complexes. -- Many metal complexes are effective initiators for the ROP of small ring monomers; however, some undergo side reactions during polymerization that lead to low molecular weight polymers and decrease the level of control in polymer formation. Ligand design and catalyst design using main group and early transition metals have played a vital role in the development of this area. In view of this, Li, Zn, AI, Ti, and Zr complexes bearing various N-, and O-mixed donor monoanionic piperazinyl- and morpholinyl-based phenolate ligands were synthesized in this project. The complexes were fully characterized by elemental analysis, NMR spectroscopy, and X-ray crystallography. In addition, using Brookhart's acid, cationic zinc complex was synthesized and characterized using ¹H, ¹³C, 1 ¹⁹F and ¹¹B NMR spectroscopy. -- The ROP reactions of rac-LA and ε-CL using Zn alkyl and alkoxide complexes were performed. Data showed that polymerization occured immediately using the alkoxide complexes; however, for the alkyl complexes, polymerization was possible only in the presence of alcohol. In addition, microwave irradiation (MW) was found to reduce reaction time significantly while maintaining control of the polymerization reaction. -- Furthermore, the AI and Li complexes are active for the ROP of ε-CL in the presence of benzyl alcohol (BnOH), while the Li complexes are also active in the absence of BnOH. Polymerization kinetics were monitored by observing the degree of conversion of ε-CL to PCL by ¹H NMR spectroscopy. The observed rates and activation energies are related to the steric effects and the outersphere substituents of the complexes. The polymers were analyzed by GPC, MALDI-TOF MS, DSC and TGA. Preliminary investigations into the copolymerization of epoxides with CO₂ using Zn and Al complexes were promising; however, further experiments are required to optimize the reaction method

Aluminum Methyl and Chloro Complexes Bearing Monoanionic Aminephenolate Ligands: Synthesis, Characterization, and Use in Polymerizations

A series of aluminum methyl and chloride complexes bearing 2­(<i>N</i>-piperazinyl-<i>N</i>′-methyl)-2-methylene-4-R′-6-R-phenolate or 2­(<i>N</i>-morpholinyl)-2-methylene-4-R′-6-R-phenolate ([ONE^R1,R2]-) {[R¹ = ^<i>t</i>Bu, R² = Me, E = NMe (<b>L1</b>); R¹= R² = ^<i>t</i>Bu, E = NMe (<b>L2</b>); R¹ = R² = ^<i>t</i>Bu, E = O (<b>L3</b>)} ligands were synthesized and characterized through elemental analysis, ¹H, ¹³C­{¹H}, and ²⁷Al NMR spectroscopy, and X-ray crystallography. Reactions of AlMe₃ with two equivalents of <b>L1</b>H-<b>L3</b>H gave {[ONE^R1,R2]₂AlMe} (<b>1</b>–<b>3</b>), while reaction of Et₂AlCl with two equivalents of <b>L1</b>H and <b>L3</b>H afforded {[ONE^R1,R2]₂AlCl} (<b>4</b> and <b>5</b>) as monometallic complexes. The catalytic activity of complexes <b>1</b>–<b>3</b> toward ring-opening polymerization (ROP) of ε-caprolactone was assessed. These complexes are more active than analogous Zn complexes for this reaction but less active than the Zn analogues for ROP of <i>rac</i>-lactide. Characteristics of the polymer as well as polymerization kinetics and mechanism were studied. Polymer end-group analyses were achieved using ¹H NMR spectroscopy and MALDI-TOF MS. Eyring analyses were performed, and the activation energies for the reactions were determined, which were significantly lower for <b>1</b> and <b>2</b> compared with <b>3</b>. This could be for several reasons: (1) the methylamine (NMe) group of <b>1</b> and <b>2</b>, which is a stronger base than the ether (O) group of <b>3</b>, might activate the incoming monomer via noncovalent interactions, and/or (2) the ether group is able to temporarily coordinate to the metal center and blocks the vacant coordination site toward incoming monomer, while the amine cannot do this. Preliminary studies using <b>4</b> and <b>5</b> toward copolymerization of cyclohexene oxide with carbon dioxide have been performed. <b>4</b> was inactive and <b>5</b> afforded polyether carbonate (66.7% epoxide conversion, polymer contains 54.0% carbonate linkages)

Aluminum Methyl and Chloro Complexes Bearing Monoanionic Aminephenolate Ligands: Synthesis, Characterization, and Use in Polymerizations

A series of aluminum methyl and chloride complexes bearing 2­(<i>N</i>-piperazinyl-<i>N</i>′-methyl)-2-methylene-4-R′-6-R-phenolate or 2­(<i>N</i>-morpholinyl)-2-methylene-4-R′-6-R-phenolate ([ONE^R1,R2]-) {[R¹ = ^<i>t</i>Bu, R² = Me, E = NMe (<b>L1</b>); R¹= R² = ^<i>t</i>Bu, E = NMe (<b>L2</b>); R¹ = R² = ^<i>t</i>Bu, E = O (<b>L3</b>)} ligands were synthesized and characterized through elemental analysis, ¹H, ¹³C­{¹H}, and ²⁷Al NMR spectroscopy, and X-ray crystallography. Reactions of AlMe₃ with two equivalents of <b>L1</b>H-<b>L3</b>H gave {[ONE^R1,R2]₂AlMe} (<b>1</b>–<b>3</b>), while reaction of Et₂AlCl with two equivalents of <b>L1</b>H and <b>L3</b>H afforded {[ONE^R1,R2]₂AlCl} (<b>4</b> and <b>5</b>) as monometallic complexes. The catalytic activity of complexes <b>1</b>–<b>3</b> toward ring-opening polymerization (ROP) of ε-caprolactone was assessed. These complexes are more active than analogous Zn complexes for this reaction but less active than the Zn analogues for ROP of <i>rac</i>-lactide. Characteristics of the polymer as well as polymerization kinetics and mechanism were studied. Polymer end-group analyses were achieved using ¹H NMR spectroscopy and MALDI-TOF MS. Eyring analyses were performed, and the activation energies for the reactions were determined, which were significantly lower for <b>1</b> and <b>2</b> compared with <b>3</b>. This could be for several reasons: (1) the methylamine (NMe) group of <b>1</b> and <b>2</b>, which is a stronger base than the ether (O) group of <b>3</b>, might activate the incoming monomer via noncovalent interactions, and/or (2) the ether group is able to temporarily coordinate to the metal center and blocks the vacant coordination site toward incoming monomer, while the amine cannot do this. Preliminary studies using <b>4</b> and <b>5</b> toward copolymerization of cyclohexene oxide with carbon dioxide have been performed. <b>4</b> was inactive and <b>5</b> afforded polyether carbonate (66.7% epoxide conversion, polymer contains 54.0% carbonate linkages)

Coupling of carbon dioxide with neat propylene oxide catalyzed by aminebisphenolato cobalt(II)/(III) complexes and ionic co-catalysts

Cobalt complexes of tetradentate amine-phenolate ligands were studied for their potential in coupling carbon dioxide with propylene oxide under neat reaction conditions. Cobalt(II) complexes afforded catalytic systems with higher TONs than analogous cobalt(III) compounds. Tetrabutylammonium bromide (TBAB) and PPN+N3- were effective co-catalysts whereas N,N-dimethylaminopyridine (DMAP) shut down reactivity. Ligands containing a pendant pyridyl donor afforded more active catalysts than those containing dimethylamine groups. Reactions proceeded well at room temperature under moderate pressures of carbon dioxide

Aluminium coordination complexes in copolymerization reactions of carbon dioxide and epoxides

Al complexes are widely used in a range of polymerization reactions (ROP of cyclic esters and cationic polymerization of alkenes). Since the discovery in 1978 that an Al porphyrin complex could copolymerize propylene oxide with carbon dioxide, Al coordination compounds have been studied extensively as catalysts for epoxide-carbon dioxide copolymerizations. The most widely studied catalysts are Al porphyrin and Al salen derivatives. This is partially due to their ability to act as mechanistic models for more reactive, paramagnetic Cr catalysts. However, this in depth mechanistic understanding could be employed to design more active Al catalysts themselves, which would be beneficial given the wide availability of this metal. Polymerization data (% CO3 linkages, Mn, Mw/Mn and TON) for these complexes are presented and mechanisms discussed. In most cases, especially those employing square-based pyramidal Al complexes, co-catalysts are required to obtain high levels of carbon dioxide incorporation. However, in some cases, the use of co-catalysts inhibits the copolymerization reaction. Lewis acidic Al phenolate complexes have been used as activators in CHO-carbon dioxide copolymerizations to increase TOF and this has recently led to the development of asymmetric copolymerization reactions. Given the ready availability of Al, the robustness of many complexes (e.g. use in immortal polymerizations) and opportunity to prepare block copolymers and other designer materials, Al complexes for copolymerization of carbon dioxide are surely worth a second look