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1.
Am J Otolaryngol ; 45(2): 104123, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38043298

RESUMEN

PURPOSE: Anxiety towards pain is correlated with increased post-surgical pain and assessed with the "Pain Catastrophizing Scale" (PCS). We assess patient reported pain and opioid usage following septorhinoplasty and their association with the PCS. METHODS: This prospective cohort study enrolled patients over 18 years of age undergoing open septorhinoplasty on an outpatient basis at a single academic institution. Participants completed the PCS preoperatively and recorded post-operative pain and analgesic use with a daily online based survey through post-operative day 5. Total opioid use and highest pain rating are assessed. RESULTS: Postoperative pain was assessed in 34 patients with a median age of 37 years (Range: 22-62y). The average highest pain rating was 6.2/10 (σ = 2.03) and occurred on post-operative day 2. A median of 20 5-mg narcotic tablets (Range: 10-25) was prescribed to study participants though only an average of 7.25 (Range: 0-15) were reported as used. Medical comorbidities and surgical characteristics, including history of anxiety, cosmetic indication, surgical revision, use of osteotomies, Doyle splints, costal or conchal cartilage grafts, or inferior turbinate reduction, were not associated with increased pain or narcotic use. Those using >10 tablets scored higher on the PCS ([10.6] v. [4.8], p = 0.025). CONCLUSION: Most patients require <10, 5 mg opioid tablets following septorhinoplasty. Surgeons should attempt to decrease opioid prescriptions while considering that patients with significant anxiety towards pain may report higher narcotic needs.


Asunto(s)
Analgésicos Opioides , Trastornos Relacionados con Opioides , Humanos , Adolescente , Adulto , Adulto Joven , Persona de Mediana Edad , Analgésicos Opioides/uso terapéutico , Estudios Prospectivos , Dolor Postoperatorio/tratamiento farmacológico , Dolor Postoperatorio/etiología , Narcóticos , Catastrofización
2.
Facial Plast Surg ; 39(6): 609-615, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37536369

RESUMEN

Early reductive rhinoplasty techniques focused on hump reduction and tip plasty with minimal focus on treating or preserving the integrity and width of the middle vault. With time, rhinoplasty surgeons noted the aesthetic and functional complications of the deformities that may occur in the middle vault with reduction techniques and developed methods to treat and also avoid these complications. Thus, the importance of protecting the integrity of the middle third of the nose has been increasingly emphasized over the years. Primary deformities of the middle vault that result in nasal obstruction require attention of the rhinoplasty surgeon, as well as preservation of support structures of the middle vault and internal nasal valve to minimize secondary deformities and functional compromise after rhinoplasty surgery.


Asunto(s)
Obstrucción Nasal , Deformidades Adquiridas Nasales , Rinoplastia , Humanos , Estética Dental , Nariz/cirugía , Rinoplastia/efectos adversos , Rinoplastia/métodos , Obstrucción Nasal/etiología , Obstrucción Nasal/cirugía , Deformidades Adquiridas Nasales/etiología , Deformidades Adquiridas Nasales/cirugía , Tabique Nasal/cirugía
3.
Cleft Palate Craniofac J ; 59(9): 1176-1184, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-34405717

RESUMEN

OBJECTIVE: This study aims to assess early adverse events and patient factors associated with complications following mandible distraction osteogenesis (MDO). MATERIALS AND METHODS: The American College of Surgeons National Surgical Quality Improvement Program-Pediatric (NSQIP-Pediatric) database, years 2012 to 2019, was queried for patients undergoing mandible advancement via relevant Current Procedural Terminology and postoperative diagnosis codes. Thirty-day adverse events and co-morbidities are assessed. RESULTS: A total of 208 patients were identified with 17.3% (n = 36) experiencing an adverse event, reoperation (n = 14), and readmission (n = 11) being most common. Patients < 365 days old at the time of operation were more likely to experience an adverse event (26.1% vs 10.8%; P = .005). However, among patients less than 1 year of age, differences in the complication rates between patients ≤ 28 days and >28 days (30.2% vs 22.2%; P = .47) and those weighing ≤ 4 kg and >4 kg (31.7% vs 11.5%; P = .063) did not reach statistical significance. CONCLUSIONS: Adverse events following mandible advancement are relatively common, though often minor. In our analysis of the NSQIP-Pediatric database, neonatal age ( ≤ 28 days) or weight ≤ 4 kg did not result in a statistically significant increase in complications among patients less than 1 year of age. Providers should consider early intervention in patients who may benefit from MDO.


Asunto(s)
Avance Mandibular , Mejoramiento de la Calidad , Niño , Bases de Datos Factuales , Humanos , Recién Nacido , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/epidemiología , Reoperación , Estudios Retrospectivos , Resultado del Tratamiento
4.
Inorg Chem ; 54(10): 4827-39, 2015 May 18.
Artículo en Inglés | MEDLINE | ID: mdl-25933172

RESUMEN

The reduction of fac-[CrCl3(P(Ph)3N(Bn)3)], (1(Cl3)), (P(Ph)3N(Bn)3 = 1,5,9-tribenzyl-3,7,11-triphenyl-1,5,9-triaza-3,7,11-triphosphacyclododecane) with Mg in the presence of dmpe (dmpe = 1,2-bis(dimethylphosphino)ethane) affords the first example of a monodinitrogen Cr(0) complex, Cr(N2)(dmpe)(P(Ph)3N(Bn)3), (2(N2)), containing a pentaphosphine coordination environment. 2(N2) is supported by a unique facially coordinating 12-membered phosphorus macrocycle containing pendant amine groups in the second coordination sphere. Treatment of 2(N2) at -78 °C with 1 equiv of [H(OEt2)2][B(C6F5)4] results in protonation of the metal center, generating the seven-coordinate Cr(II)-N2 hydride complex, [Cr(H)(N2)(dmpe)(P(Ph)3N(Bn)3)][B(C6F5)4], [2(H)(N2)](+). Treatment of 2((15)N2) with excess triflic acid at -50 °C afforded a trace amount of (15)NH4(+) from the reduction of the coordinated (15)N2 ligand (electrons originate from Cr). Electronic structure calculations were employed to evaluate the pKa values of three protonated sites of 2(N2) (metal center, pendant amine, and N2 ligand) and were used to predict the thermodynamically preferred Cr-NxHy intermediates in the N2 reduction pathway for 2(N2) and the recently published complex trans-[Cr(N2)2(P(Ph)4N(Bn)4)] upon the addition of protons and electrons.


Asunto(s)
Cromo/química , Complejos de Coordinación/química , Cicloparafinas/química , Nitrógeno/química , Protones , Aminas/química , Derivados del Benceno/química , Magnesio/química , Fosfinas/química , Termodinámica
5.
J Community Health ; 40(4): 802-7, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25700790

RESUMEN

Vestibular rehabilitation therapy (VRT) can benefit patients with a variety of balance and vestibular disorders. This expanding field requires knowledgeable and experienced therapists; however, the practice and experience of those providing this care may vary greatly. The purpose of this study was to analyze variations in training and practice patterns among practicing vestibular rehabilitation therapists. Case-controlled cohort study. Investigation of outpatient physical therapy and audiology practices that offer vestibular rehabilitation conducted by a tertiary academic referral center. Questionnaire-based investigation of level of training in vestibular disorders and therapy, practice patterns of vestibular rehabilitation, and referral sources for VRT patients. We identified 27 subjects within the state of Kentucky who practice vestibular rehabilitation and the questionnaire response rate was 63%. Responses indicated that 53% of respondents had no training in VRT during their professional degree program. Attendance of a course requiring demonstration of competence and techniques was 24% of participants. The development of VRT certification was significantly more favored by those who attended such courses compared with those who did not (p = 0.01). 50% of therapists have direct access to patients without physician referrals. There is a wide range of educational background and training among those practicing VRT. This variability in experience may affect care provided within some communities. Certification is not necessary for the practice of VRT but the development of certification is favored among some therapists to improve standardization of practice of this important specialty.


Asunto(s)
Modalidades de Fisioterapia/educación , Modalidades de Fisioterapia/normas , Enfermedades Vestibulares/rehabilitación , Adulto , Estudios de Casos y Controles , Certificación , Femenino , Humanos , Kentucky , Masculino , Persona de Mediana Edad
6.
Inorg Chem ; 53(7): 3899-906, 2014 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-24660986

RESUMEN

The aluminum complexes (LMes(2-))AlCl(THF) (3) and (LDipp(-))AlCl2 (4) (LMes = N,N'-bis[2,4,6-trimethylphenyl]-2,3-dimethyl-1,4-diazabutadiene, LDipp = N,N'-bis[2,6-diisopropylphenyl]-2,3-dimethyl-1,4-diazabutadiene) were prepared by direct reduction of the ligands with sodium metal followed by salt metathesis with AlCl3. The (LMes(-))AlCl2 (5) complex was prepared through one-electron oxidative functionalization of 3 with either AgCl or CuCl. Complex 3 was characterized using (1)H and (13)C NMR spectoscopies. Single-crystal X-ray diffraction analysis of the complexes revealed that 3-5 are all four-coordinate, with 3 exhibiting a trigonal pyramidal geometry, while 4 and 5 exist between trigonal pyramidal and tetrahedral. Notable in the LMes complexes 3 and 5 is a systematic lengthening of the C-Nimido bonds and shortening of the C-C bond in the N-C-C-N backbone with increased electron density on the ligand. The geometries of the complexes 3 and 5 were optimized using DFT, which showed primarily ligand-based frontier orbitals, supporting the analysis of the solid-state structural data. The complexes 3-5 were also characterized by electrochemistry. The cyclic voltamogram of complex 3 showed an oxidation processes at -0.94 and -0.03 V versus ferrocene, while complexes 4 and 5 exhibit both reduction (-1.37 and -1.34 V, respectively) and oxidation (-0.62 and -0.73 V, respectively) features.

7.
J Am Chem Soc ; 135(31): 11493-6, 2013 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-23865433

RESUMEN

We report a rare example of a Cr-N2 complex supported by a 16-membered phosphorus macrocycle containing pendant amine bases. Reactivity with acid afforded hydrazinium and ammonium, representing the first example of N2 reduction by a Cr-N2 complex. Computational analysis examined the thermodynamically favored protonation steps of N2 reduction with Cr leading to the formation of hydrazine.

8.
J Am Chem Soc ; 135(26): 9700-12, 2013 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-23631473

RESUMEN

A nickel bis(diphosphine) complex containing pendant amines in the second coordination sphere, [Ni(P(Cy)2N(t-Bu)2)2](BF4)2 (P(Cy)2N(t-Bu)2 = 1,5-di(tert-butyl)-3,7-dicyclohexyl-1,5-diaza-3,7-diphosphacyclooctane), is an electrocatalyst for hydrogen oxidation. The addition of hydrogen to the Ni(II) complex gives three isomers of the doubly protonated Ni(0) complex [Ni(P(Cy)2N(t-Bu)2H)2](BF4)2. Using the pKa values and Ni(II/I) and Ni(I/0) redox potentials in a thermochemical cycle, the free energy of hydrogen addition to [Ni(P(Cy)2N(t-Bu)2)2](2+) was determined to be -7.9 kcal mol(-1). The catalytic rate observed in dry acetonitrile for the oxidation of H2 depends on base size, with larger bases (NEt3, t-BuNH2) resulting in much slower catalysis than n-BuNH2. The addition of water accelerates the rate of catalysis by facilitating deprotonation of the hydrogen addition product before oxidation, especially for the larger bases NEt3 and t-BuNH2. This catalytic pathway, where deprotonation occurs prior to oxidation, leads to an overpotential that is 0.38 V lower compared to the pathway where oxidation precedes proton movement. Under the optimal conditions of 1.0 atm H2 using n-BuNH2 as a base and with added water, a turnover frequency of 58 s(-1) is observed at 23 °C.


Asunto(s)
Aminas/química , Complejos de Coordinación/química , Hidrógeno/química , Níquel/química , Catálisis , Técnicas Electroquímicas , Modelos Moleculares , Conformación Molecular , Oxidación-Reducción
9.
Inorg Chem ; 52(7): 4026-39, 2013 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-23506204

RESUMEN

The addition of acids to ferrous dinitrogen complexes [FeX(N2)(P(Et)N(Me)P(Et))(dmpm)](+) (X = H, Cl, or Br; P(Et)N(Me)P(Et) = Et2PCH2N(Me)CH2PEt2; and dmpm = Me2PCH2PMe2) gives protonation at the pendent amine of the diphosphine ligand rather than at the dinitrogen ligand. This protonation increased the νN2 band of the complex by 25 cm(-1) and shifted the Fe(II/I) couple by 0.33 V to a more positive potential. A similar IR shift and a slightly smaller shift of the Fe(II/I) couple (0.23 V) was observed for the related carbonyl complex [FeH(CO)(P(Et)N(Me)P(Et))(dmpm)](+). [FeH(P(Et)N(Me)P(Et))(dmpm)](+) was found to bind N2 about three times more strongly than NH3. Computational analysis showed that coordination of N2 to Fe(II) centers increases the basicity of N2 (vs free N2) by 13 and 20 pKa units for the trans halides and hydrides, respectively. Although the iron center increases the basicity of the bound N2 ligand, the coordinated N2 is not sufficiently basic to be protonated. In the case of ferrous dinitrogen complexes containing a pendent methylamine, the amine site was determined to be the most basic site by 30 pKa units compared to the N2 ligand. The chemical reduction of these ferrous dinitrogen complexes was performed in an attempt to increase the basicity of the N2 ligand enough to promote proton transfer from the pendent amine to the N2 ligand. Instead of isolating a reduced Fe(0)-N2 complex, the reduction resulted in isolation and characterization of HFe(Et2PC(H)N(Me)CH2PEt2)(P(Et)N(Me)P(Et)), the product of oxidative addition of the methylene C-H bond of the P(Et)N(Me)P(Et) ligand to Fe.

10.
Inorg Chem ; 52(17): 9975-88, 2013 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-23945020

RESUMEN

Two new tetraphosphine ligands, P(nC-PPh2)2N(Ph)2 (1,5-diphenyl-3,7-bis((diphenylphosphino)alkyl)-1,5-diaza-3,7-diphosphacyclooctane; alkyl = (CH2)2, n = 2 (L2); (CH2)3, n = 3 (L3)), have been synthesized. Coordination of these ligands to cobalt affords the complexes [Co(II)(L2)(CH3CN)](2+) and [Co(II)(L3)(CH3CN)](2+), which are reduced by KC8 to afford [Co(I)(L2)(CH3CN)](+) and [Co(I)(L3)(CH3CN)](+). Protonation of the Co(I) complexes affords [HCo(III)(L2)(CH3CN)](2+) and [HCo(III)(L3)(CH3CN)](2+). The cyclic voltammetry of [HCo(III)(L2)(CH3CN)](2+), analyzed using digital simulation, is consistent with an ErCrEr reduction mechanism involving reversible acetonitrile dissociation from [HCo(II)(L2)(CH3CN)](+) and resulting in formation of HCo(I)(L2). Reduction of HCo(III) also results in cleavage of the H-Co bond from HCo(II) or HCo(I), leading to formation of the Co(I) complex [Co(I)(L2)(CH3CN)](+). Under voltammetric conditions, the reduced cobalt hydride reacts with a protic solvent impurity to generate H2 in a monometallic process involving two electrons per cobalt. In contrast, under bulk electrolysis conditions, H2 formation requires only one reducing equivalent per [HCo(III)(L2)(CH3CN)](2+), indicating a bimetallic route wherein two cobalt hydride complexes react to form 2 equiv of [Co(I)(L2)(CH3CN)](+) and 1 equiv of H2. These results indicate that both HCo(II) and HCo(I) can be formed under electrocatalytic conditions and should be considered as potential catalytic intermediates.

11.
Artículo en Inglés | MEDLINE | ID: mdl-37780676

RESUMEN

Objective: The objective of this study is to provide a state-of-the-art review on the use of anesthetics for in-office facial plastic procedures. Methods: A search was performed on PubMed, Embase, Web of Science, and Cochrane Review using the keywords "anesthesia," "office-based procedures," "local anesthesia," "facial plastics," "oral sedation," "moderate sedation," and "deep sedation." Results and Conclusions: Over the past few decades, the shift toward in-office invasive procedures has increased patient convenience and decreased hospital resource utilization. Many tools exist to reduce patient anxiety and discomfort in an office-based setting. With proper patient selection and technique, facial plastic surgeons can adequately anesthetize patients to perform Mohs reconstruction, cutaneous excisions, blepharoplasty, face-lifts, and other in-office procedures.

12.
J Phys Chem A ; 116(48): 11946-56, 2012 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-23098094

RESUMEN

We investigate the relationship between intramolecular rotational dynamics and molecular and crystal structure in 4,4'-dimethoxyoctafluorobiphenyl. The techniques are electronic structure calculations, X-ray diffractometry, and (1)H and (19)F solid state nuclear magnetic resonance relaxation. We compute and measure barriers for coupled methyl group rotation and methoxy group libration. We compare the structure and the structure-motion relationship in 4,4'-dimethoxyoctafluorobiphenyl with the structure and the structure-motion relationship in related compounds in order to observe trends concerning the competition between intramolecular and intermolecular interactions. The (1)H spin-lattice relaxation is nonexponential in both the high-temperature short-correlation time limit and in the low-temperature long-correlation time limit, albeit for different reasons. The (19)F spin-lattice relaxation is nonexponential at low temperatures and it is exponential at high temperatures.


Asunto(s)
Compuestos de Bifenilo/química , Simulación de Dinámica Molecular , Cristalografía por Rayos X , Electrones , Flúor/química , Espectroscopía de Resonancia Magnética , Modelos Moleculares , Estructura Molecular , Protones , Rotación
13.
Int J Pediatr Otorhinolaryngol ; 155: 111075, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35189448

RESUMEN

OBJECTIVE: To determine whether children with unilateral sensorineural hearing loss (USNHL) and unilateral conductive hearing loss (UCHL) have higher levels of fatigue than literature reported normal hearing (LRNH) children. METHODS: This was a cross-sectional survey utilizing the PedsQL™ Multidimensional Fatigue Scale administered to children with unilateral hearing loss (UHL) and their parents at two tertiary care academic medical centers and a nationwide microtia/atresia conference. The PedsQL™ Multidimensional Fatigue Scale was used to compare child and parental proxy reports of fatigue among USNHL, UCHL, and LRNH children. ANOVA and post-hoc Tukey Honest Significant Difference testing were used for statistical analysis. RESULTS: Of 69 children included in the study, 42 had UCHL (61%) and 27 (39%) had USNHL. Children with USNHL reported more total fatigue (mean 69.1, SD 19.3) than LRNH children (mean 80.5, SD 13.3; difference -11.4; 95% CI: -19.98 to -2.84) and children with UCHL (mean 78.0, SD 14.5; difference -8.95; 95% CI: -17.86 to 0.04). Children with UCHL reported similar levels of fatigue compared to LRNH children (difference -2.5; 95% CI: -9.95 to 5.03). Parents of children with USNHL reported greater levels of fatigue (mean 67.6, SD 22.6) in their children than parents of LRNH children (mean 89.6, SD 11.4; difference -22.0; 95% CI: -29.8 to -14.3) and parents of children with UCHL (mean 76.2, SD 17.3; difference -8.6; 95% CI: -17.5 to 0.21). Parents of children with UCHL also report higher levels of fatigue than parents of LRNH children (difference -13.4; 95% CI: -19.98 to -6.84). CONCLUSIONS: Children with USNHL reported greater levels of fatigue than LRNH children and children with UCHL. Results implicate cognitive load as an important consideration in children with hearing loss. The measurement of fatigue may be a useful indicator to determine the benefit of intervention (e.g., amplification) for these children.


Asunto(s)
Audífonos , Pérdida Auditiva Sensorineural , Pérdida Auditiva Unilateral , Niño , Estudios Transversales , Fatiga/diagnóstico , Fatiga/etiología , Pérdida Auditiva Conductiva/psicología , Pérdida Auditiva Sensorineural/diagnóstico , Pérdida Auditiva Unilateral/diagnóstico , Pérdida Auditiva Unilateral/psicología , Humanos
14.
J Am Chem Soc ; 133(15): 5861-72, 2011 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-21438562

RESUMEN

A series of mononuclear nickel(II) bis(diphosphine) complexes [Ni(P(Ph)(2)N(C6H4X)(2))(2)](BF(4))(2) (P(Ph)(2)N(C6H4X)(2) = 1,5-di(para-X-phenyl)-3,7-diphenyl-1,5-diaza-3,7-diphosphacyclooctane; X = OMe, Me, CH(2)P(O)(OEt)(2), Br, and CF(3)) have been synthesized and characterized. X-ray diffraction studies reveal that [Ni(P(Ph)(2)N(C6H4Me)(2))(2)](BF(4))(2) and [Ni(P(Ph)(2)N(C6H4OMe)(2))(2)](BF(4))(2) are tetracoordinate with distorted square planar geometries. The Ni(II/I) and Ni(I/0) redox couples of each complex are electrochemically reversible in acetonitrile with potentials that are increasingly cathodic as the electron-donating character of X is increased. Each of these complexes is an efficient electrocatalyst for hydrogen production at the potential of the Ni(II/I) couple. The catalytic rates generally increase as the electron-donating character of X is decreased, and this electronic effect results in the favorable but unusual situation of obtaining higher catalytic rates as overpotentials are decreased. Catalytic studies using acids with a range of pK(a) values reveal that turnover frequencies do not correlate with substrate acid pK(a) values but are highly dependent on the acid structure, with this effect being related to substrate size. Addition of water is shown to dramatically increase catalytic rates for all catalysts. With [Ni(P(Ph)(2)N(C6H4CH2P(O)(OEt)2)(2))(2)](BF(4))(2) using [(DMF)H](+)OTf(-) as the acid and with added water, a turnover frequency of 1850 s(-1) was obtained.

15.
Inorg Chem ; 50(7): 2754-63, 2011 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-21355612

RESUMEN

We have synthesized the complex [Ru(bpy)(2)(bpy(OH)(2))](2+) (bpy =2,2'-bipyridine, bpy(OH)(2) = 4,4'-dihydroxy-2,2'-bipyridine). Experimental results coupled with computational studies were utilized to investigate the structural and electronic properties of the complex, with particular attention paid toward the effects of deprotonation on these properties. The most distinguishing feature observed in the X-ray structural data is a shortening of the CO bond lengths in the modified ligand upon deprotonation. Similar results are also observed in the computational studies as the CO bond becomes double bond in character after deprotonating the complex. Electrochemically, the hydroxy-modified bipyridyl ligand plays a significant role in the redox properties of the complex. When protonated, the bpy(OH)(2) ligand undergoes irreversible reduction processes; however, when deprotonated, reduction of the substituted ligand is no longer observed, and several new irreversible oxidation processes associated with the modified ligand arise. pH studies indicate [Ru(bpy)(2)(bpy(OH)(2))](2+) has two distinct deprotonations at pK(a1) = 2.7 and pK(a2) = 5.8. The protonated [Ru(bpy)(2)(bpy(OH)(2))](2+) complex has a characteristic UV/Visible absorption spectrum similar to the well-studied complex [Ru(bpy)(3)](2+) with bands arising from Metal-to-Ligand Charge Transfer (MLCT) transitions. When the complex is deprotonated, the absorption spectrum is altered significantly and becomes heavily solvent dependent. Computational methods indicate that the deprotonated bpy(O(-))(2) ligand mixes heavily with the metal d orbitals leading to a new absorption manifold. The transitions in the complex have been assigned as mixed Metal-Ligand to Ligand Charge Transfer (MLLCT).


Asunto(s)
Complejos de Coordinación/química , Electrones , Rutenio/química , Cristalografía por Rayos X , Modelos Moleculares , Estructura Molecular
16.
Inorg Chem ; 50(23): 11914-28, 2011 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-22040085

RESUMEN

Hydrides of numerous transition metal complexes can be generated by the heterolytic cleavage of H(2) gas such that they offer alternatives to using main group hydrides in the regeneration of ammonia borane, a compound that has been intensely studied for hydrogen storage applications. Previously, we reported that HRh(dmpe)(2) (dmpe = 1,2-bis(dimethylphosphinoethane)) was capable of reducing a variety of BX(3) compounds having a hydride affinity (HA) greater than or equal to the HA of BEt(3). This study examines the reactivity of less expensive cobalt and nickel hydride complexes, HCo(dmpe)(2) and [HNi(dmpe)(2)](+), to form B-H bonds. The hydride donor abilities (ΔG(H(-))°) of HCo(dmpe)(2) and [HNi(dmpe)(2)](+) were positioned on a previously established scale in acetonitrile that is cross-referenced with calculated HAs of BX(3) compounds. The collective data guided our selection of BX(3) compounds to investigate and aided our analysis of factors that determine favorability of hydride transfer. HCo(dmpe)(2) was observed to transfer H(-) to BX(3) compounds with X = H, OC(6)F(5), and SPh. The reaction with B(SPh)(3) is accompanied by the formation of dmpe-(BH(3))(2) and dmpe-(BH(2)(SPh))(2) products that follow from a reduction of multiple B-SPh bonds and a loss of dmpe ligands from cobalt. Reactions between HCo(dmpe)(2) and B(SPh)(3) in the presence of triethylamine result in the formation of Et(3)N-BH(2)SPh and Et(3)N-BH(3) with no loss of a dmpe ligand. Reactions of the cationic complex [HNi(dmpe)(2)](+) with B(SPh)(3) under analogous conditions give Et(3)N-BH(2)SPh as the final product along with the nickel-thiolate complex [Ni(dmpe)(2)(SPh)](+). The synthesis and characterization of HCo(dedpe)(2) (dedpe = Et(2)PCH(2)CH(2)PPh(2)) from H(2) and a base is also discussed, including the formation of an uncommon trans dihydride species, trans-[(H)(2)Co(dedpe)(2)][BF(4)].

17.
Inorg Chem ; 50(21): 10908-18, 2011 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-21999814

RESUMEN

A series of [Ni(P(R)(2)N(Ph)(2))(2)(CH(3)CN)](BF(4))(2) complexes containing the cyclic diphosphine ligands [P(R)(2)N(Ph)(2) = 1,5-diaza-3,7-diphosphacyclooctane; R = benzyl (Bn), n-butyl (n-Bu), 2-phenylethyl (PE), 2,4,4-trimethylpentyl (TP), and cyclohexyl (Cy)] have been synthesized and characterized. X-ray diffraction studies reveal that the cations of [Ni(P(Bn)(2)N(Ph)(2))(2)(CH(3)CN)](BF(4))(2) and [Ni(P(n-Bu)(2)N(Ph)(2))(2)(CH(3)CN)](BF(4))(2) have distorted trigonal bipyramidal geometries. The Ni(0) complex [Ni(P(Bn)(2)N(Ph)(2))(2)] was also synthesized and characterized by X-ray diffraction studies and shown to have a distorted tetrahedral structure. These complexes, with the exception of [Ni(P(Cy)(2)N(Ph)(2))(2)(CH(3)CN)](BF(4))(2), all exhibit reversible electron transfer processes for both the Ni(II/I) and Ni(I/0) couples and are electrocatalysts for the production of H(2) in acidic acetonitrile solutions. The heterolytic cleavage of H(2) by [Ni(P(R)(2)N(Ph)(2))(2)(CH(3)CN)](BF(4))(2) complexes in the presence of p-anisidine or p-bromoaniline was used to determine the hydride donor abilities of the corresponding [HNi(P(R)(2)N(Ph)(2))(2)](BF(4)) complexes. However, for the catalysts with the most bulky R groups, the turnover frequencies do not parallel the driving force for elimination of H(2), suggesting that steric interactions between the alkyl substituents on phosphorus and the nitrogen atom of the pendant amines play an important role in determining the overall catalytic rate.

18.
Ear Nose Throat J ; 100(10_suppl): 1101S-1106S, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32584613

RESUMEN

OBJECTIVES: Head and neck squamous cell carcinoma (HNSCC) is rare in patients younger than 40 years. Many practitioners suspect HNSCC is a more aggressive disease in this age group, and perhaps increasing in incidence; however, there are scant and conflicting data to support this assertion. We sought to compare outcomes for young patients with non-human papillomavirus (HPV)-related HNSCC to those of older patients. METHODS: A retrospective chart review of patients with HNSCC treated from 2004 to 2016 at 2 tertiary referral centers. Patients aged 18 to 40 with p16-negative HNSCC were included in the young patient cohort (n = 59). A randomly selected stage- and subsite-matched cohort aged 55 to 65 was analyzed for comparison (n = 114). RESULTS: When considering all patients with HNSCC, patients younger than 40 were more likely to have oral tongue cancer (62.7%) compared to patients age 55 to 65 (16.9%). When an older patient cohort was stage- and subsite-matched to the young patient cohort, there were more never smokers (49.2% vs 17.5% of older patients, P < .01) and females (40.7% vs 24.6% of older patients, P = .028) in the young patient group. The young patient cohort had better average overall survival than the older group (14.4 vs 8.1 years, respectively, P = .02), but similar average disease-free survival (6.2 years vs 6.6 years, respectively, P = .67); 50.9% of young patients had tumors with adverse histologic features versus 42.0% of older patients (P = .28). The young patients demonstrated a superior average conditional survival after recurrence (9.8 years vs 3.2 years for older patients, P < .01). CONCLUSIONS: Despite the limitations of study design, these data suggest that young patients who develop non-HPV-related HNSCC tend to have similarly aggressive disease, but longer overall survival and better survival after recurrence. These findings may be attributable to better overall health as evidenced by fewer comorbidities.


Asunto(s)
Factores de Edad , Neoplasias de Cabeza y Cuello/mortalidad , Carcinoma de Células Escamosas de Cabeza y Cuello/mortalidad , Neoplasias de la Lengua/mortalidad , Adolescente , Adulto , Anciano , Femenino , Neoplasias de Cabeza y Cuello/patología , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Carcinoma de Células Escamosas de Cabeza y Cuello/patología , Análisis de Supervivencia , Neoplasias de la Lengua/patología , Adulto Joven
19.
J Org Chem ; 75(10): 3529-32, 2010 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-20408591

RESUMEN

Concise total syntheses of Strychnos alkaloids strychnine (1) and akuammicine (2) have been realized in 13 and 6 operations, respectively. Key steps include (1) the vinylogous Mannich reaction; (2) a novel, sequential one-pot spirocyclization/intramolecular aza-Baylis-Hillman reaction; and (3) a Heck cyclization. The synthesis of 1 proceeds via the Wieland-Gumlich aldehyde (26).


Asunto(s)
Alcaloides/síntesis química , Indoles/síntesis química , Estricnina/síntesis química , Alcaloides/química , Cristalografía por Rayos X , Indoles/química , Modelos Moleculares , Estructura Molecular , Estereoisomerismo , Estricnina/química
20.
Inorg Chem ; 49(20): 9718-27, 2010 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-20866081

RESUMEN

The oxidative electrochemistries of a series of chiral bisphosphinoferrocene ligands, 1,1'-bis(2,4-dialkylphosphetanyl)ferrocene (FerroTANE) and 1,1'-bis(2,5-dialkylphospholanyl)ferrocene (FerroLANE), were examined. The reversibility of the oxidation is sensitive to the steric bulk of the alkyl groups. New transition metal compounds and phosphine chalcogenides of these ligands were prepared and characterized. X-ray crystal structures of 10 of these compounds are reported. The percent buried volume (%V(bur)) is a recently developed measurement based on crystallographic data that examines the steric bulk of N-heterocyclic carbene and phosphine ligands. The %V(bur) for the FerroTANE and FerroLANE structures with methyl or ethyl substituents suggests these ligands are similar in steric properties to 1,1'-bis(diphenylphosphino)ferrocene (dppf). In addition the %V(bur) has been found to correlate well with the Tolman cone angle for phosphine chalcogenides. The oxidative electrochemistries of the transition metal complexes occur at more positive potentials than the free ligands. While a similar positive shift is seen for the oxidative electrochemistries of the phosphine chalcogenides, the oxidation of the phosphine selenides does not occur at the iron center, but rather oxidation occurs at the selenium atoms.

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