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Wildfires at the wildland-urban interface (WUI) are increasingly common. The impacts of such events are likely distinct from those that occur strictly in wildland areas, as we would expect an elevated likelihood of soil contamination due to the combustion of anthropogenic materials. We evaluated the impacts of a wildfire at the WUI on soil contamination, sampling soils from residential and nonresidential areas located inside and outside the perimeter of the 2021 Marshall Fire in Colorado, USA. We found that fire-affected residential properties had elevated concentrations of some heavy metals (including Zn, Cu, Cr, and Pb), but the concentrations were still below levels of likely concern, and we observed no corresponding increases in concentrations of polycyclic aromatic hydrocarbons (PAHs). The postfire increases in metal concentrations were not generally observed in the nonresidential soils, highlighting the importance of combustion of anthropogenic materials for potential soil contamination from wildfires at the WUI. While soil contamination from the 2021 Marshall Fire was lower than expected, and likely below the threshold of concern for human health, our study highlights some of the challenges that need to be considered when assessing soil contamination after such fires.
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Incêndios , Metais Pesados , Incêndios Florestais , Humanos , Solo , ColoradoRESUMO
Three new tridentate copper(II) N-heterocyclic carbene (NHC) complexes have been obtained and characterized with symmetrical C-4 substitutions on their pendent pyridine rings. Substitutions including methyl (Me), methoxy (OMe), and chloro (Cl) groups, which extend the library pincer Cu-NHC complexes under investigation, modify the impact of pyridinyl basicity on NCN pincer complexes. Both ligand precursors and copper(II) complexes are characterized using a range of techniques, including nuclear magnetic resonance (NMR) spectroscopy for 1H, 13C, 31P, and 19F nuclei, electrospray ionization mass spectrometry (ESI-MS), X-ray crystallography, cyclic voltammetry, and UV-Vis spectroscopy. The pyridine substitutions lead to minimal changes to bond lengths and angles in the X-ray crystal structures of these related complexes; there is a pronounced impact on the electrochemical behavior of both the ligand precursors and copper complexes in the solution. The substitution in the pyridinyl units of these complexes show an impact on the catalytic reactivity of these complexes as applied to a model C-N bond-forming reaction (CEL cross-coupling) under well-established conditions; however, this observation does not correlate to the expected change in basicity in these ligands.
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A new tridentate Cu2+ complex based on (E)-1-(pyridin-2-yl)-N-(quinolin-8-yl)methanimine (PQM) was generated and characterized to support the activation of diazo compounds for the formation of new C-N bonds. This neutral Schiff base ligand was structurally characterized to coordinate with copper(II) in an equatorial fashion, yielding a distorted octahedral complex. Upon characterization, this copper(II) complex was used to catalyze an efficient and cost-effective protocol for C-N bond formation between N-nucleophiles and copper carbene complexes arising from the activation of diazo carbonyl compounds. A substrate scope of approximately 15 different amine-based substrates was screened, yielding 2° or 3° amine products with acceptable to good yields under mild reaction conditions. Reactivity towards phenol and thiophenol were also screened, showing relatively weak C-O or C-S bond formation under optimized conditions.
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We present a sodium trifluoroacetate (CF3CO2Na) mediated copper-catalyzed aza-Michael addition of aromatic amines with activated olefins under mild, aqueous reaction conditions. This simplistic protocol employs a copper catalyst (10 mol%) and water as solvent. This transformation occurs precisely with aromatic substituted amines containing both electron-donating (EDG) and electron-withdrawing (EWG) groups. A broad range of substrates were tested under the optimized conditions, which are producing good to moderate yields.
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OBJECTIVE: Surgical complications have substantial impact on healthcare costs. We propose an analysis of the financial impact of postoperative complications. SUMMARY OF BACKGROUND DATA: Both complications and preoperative patient risk have been shown to increase costs following surgery. The extent of cost increase due to specific complications has not been well described. METHODS: A single institution's American College of Surgeons National Surgical Quality Improvement Program data was queried from 2012 to 2018 and merged with institutional cost data for each encounter. A mixed effects multivariable generalized linear model was used to estimate the mean relative increase in hospital cost due to each complication, adjusting for patient and procedure-level fixed effects clustered by procedure. Potential savings were calculated based on projected decreases in complication rates and theoretical hospital volume. RESULTS: There were 11,897 patients linked between the 2 databases. The rate of any American College of Surgeons National Surgical Quality Improvement Program complication was 11.7%. The occurrence of any complication resulted in a 1.5-fold mean increase in direct hospital cost [95% confidence interval (CI) 1.49-1.58]. The top 6 most costly complications were postoperative septic shock (4.0-fold, 95% CI 3.58-4.43) renal insufficiency/failure (3.3-fold, 95% CI 2.91-3.65), any respiratory complication (3.1-fold, 95% CI 2.94-3.36), cardiac arrest (3.0-fold, 95% CI 2.64-3.46), myocardial infarction (2.9-fold, 95% CI 2.43-3.42) and mortality within 30 days (2.2-fold, 95% CI 2.01-2.48). Length of stay (6.5 versus 3.2 days, P < 0.01), readmission rate (29.1% vs 3.1%, P < 0.01), and discharge destination outside of home (20.5% vs 2.7%, P < 0.01) were significantly higher in the population who experienced complications. CONCLUSIONS: Decreasing complication rates through preoperative optimization will improve patient outcomes and lead to substantial cost savings.
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Redução de Custos , Custos Hospitalares , Complicações Pós-Operatórias/economia , Complicações Pós-Operatórias/prevenção & controle , Idoso , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos RetrospectivosRESUMO
OBJECTIVE: We compare consensus recommendations for 5 surgical procedures to prospectively collected patient consumption data. To address local variation, we combined data from multiple hospitals across the country. SUMMARY OF BACKGROUND DATA: One approach to address the opioid epidemic has been to create prescribing consensus reports for common surgical procedures. However, it is unclear how these guidelines compare to patient-reported data from multiple hospital systems. METHODS: Prospective observational studies of surgery patients were completed between 3/2017 and 12/2018. Data were collected utilizing post-discharge surveys and chart reviews from 5 hospitals (representing 3 hospital systems) in 5 states across the USA. Prescribing recommendations for 5 common surgical procedures identified in 2 recent consensus reports were compared to the prospectively collected aggregated data. Surgeries included: laparoscopic cholecystectomy, open inguinal hernia repair, laparoscopic inguinal hernia repair, partial mastectomy without sentinel lymph node biopsy, and partial mastectomy with sentinel lymph node biopsy. RESULTS: Eight hundred forty-seven opioid-naïve patients who underwent 1 of the 5 studied procedures reported counts of unused opioid pills after discharge. Forty-one percent did not take any opioid medications, and across all surgeries, the median consumption was 3 5âmg oxycodone pills or less. Generally, consensus reports recommended opioid quantities that were greater than the 75th percentile of consumption, and for 2 procedures, recommendations exceeded the 90th percentile of consumption. CONCLUSIONS: Although consensus recommendations were an important first step to address opioid prescribing, our data suggests that following these recommendations would result in 47%-56% of pills prescribed remaining unused. Future multi-institutional efforts should be directed toward refining and personalizing prescribing recommendations.
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Analgésicos Opioides/uso terapêutico , Consenso , Prescrições de Medicamentos/estatística & dados numéricos , Uso de Medicamentos/estatística & dados numéricos , Dor Pós-Operatória/tratamento farmacológico , Guias de Prática Clínica como Assunto , Procedimentos Cirúrgicos Operatórios , Hospitais , Humanos , Estados UnidosRESUMO
The coupling of phenylboronic acids with poorly-activated imidazoles is studied as a model system to explore the use of copper-catalyzed Chan-Evans-Lam (CEL) coupling for targeted C-N bond forming reactions. Optimized CEL reaction conditions are reported for four phenanthroline-based ligand systems, where the ligand 4,5-diazafluoren-9-one (dafo, L2) with 1 molar equivalent of potassium carbonate yielded the highest reactivity. The substrate 2-nitroimidazole (also known as azomycin) has documented antimicrobial activity against a range of microbes. Here N-arylation of 2-nitroimidazole with a range of aryl boronic acids has been successfully developed by copper(II)-catalyzed CEL reactions. Azomycin and a range of newly arylated azomycin derivatives were screened against S.â pneumoniae, where 1-(4-(benzyloxy)phenyl)-2-nitro-1H-imidazole (3d) was demonstrated to have a minimal inhibition concentration value of 3.3â µg/mL.
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Cobre , Nitroimidazóis , Ácidos Borônicos/química , Catálise , Cobre/química , Ligantes , Nitroimidazóis/farmacologiaRESUMO
In this study, kartogenin was incorporated into an electrospun blend of polycaprolactone and poly(lactic-co-glycolic acid) (1:1) to determine the feasibility of this system for sustained drug delivery. Kartogenin is a small-molecule drug that could enhance the outcome of microfracture, a cartilage restoration procedure, by selectively stimulating chondrogenic differentiation of endogenous bone marrow mesenchymal stem cells. Experimental results showed that kartogenin did not affect the electrospinnability of the polymer blend, and it had negligible effects on fiber morphology and scaffold mechanical properties. The loading efficiency of kartogenin into electrospun membranes was nearly 100%, and no evidence of chemical reaction between kartogenin and the polymers was detected by Fourier transform infrared spectroscopy. Analysis of the released drug using high-performance liquid chromatography-photodiode array detection indicated an abundance of kartogenin and only a small amount of its major hydrolysis product. Kartogenin displayed a typical biphasic release profile, with approximately 30% being released within 24 h followed by a much slower, constant rate of release up to 28 days. Although additional development is needed to tune the release kinetics and address issues common to electrospun scaffolds (e.g., high fiber density), the results of this study demonstrated that a scaffold electrospun from biodegradable synthetic polymers is a suitable kartogenin delivery vehicle.
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Poliésteres , Alicerces Teciduais , Anilidas , Condrogênese , Ácidos Ftálicos , Poliésteres/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Polímeros/química , Alicerces Teciduais/químicaRESUMO
BACKGROUND: Procedure-based opioid-prescribing guidelines have reduced the amount of opioids prescribed after surgery; however, many patients are still overprescribed opioids. The 24-h predischarge opioid consumption (PDOC) metric has been proposed to guide patient-centered prescribing. MATERIALS AND METHODS: This is a single-institution, retrospective study of patients who underwent major abdominal surgery. We assessed the correlation between inpatient opioid use and discharge prescriptions using morphine milligram equivalents (MMEs). The adequacy of discharge prescriptions for individual patients was assessed using 2 models, one assuming constant opioid use (based on 24-h PDOC) and the other assuming a linear taper. RESULTS: Of 596 included patients, gastric bypass and colectomy were the most common operations. Median length of stay was 3.5 d. Inpatient opioid use and discharge prescriptions were weakly correlated (r = 0.35). Patients with no opioid use 24 h before discharge (n = 133, 22.3%) were frequently discharged with opioid prescriptions. Patients with high opioid use (24-h PDOC >60 MME) were often discharged with prescriptions that would have lasted <48 h (164/200, 82%). Assuming constant opioid use, discharge prescriptions would have lasted patients a median of 5.1 d. With linear opioid tapering, 440 (72.9%) patients would have had leftover pills. A theoretical discharge prescription of 4 times 24-h PDOC would reduce the median prescription by 130 MMEs and allow a linear taper for 97.6% of patients. CONCLUSIONS: At our institution, opioid prescribing was rarely patient-centered, with little correlation between patient's inpatient opioid use and discharge prescriptions. This leads to overprescribing for most patients and underprescribing for others.
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Analgésicos Opioides/efeitos adversos , Prescrições de Medicamentos/normas , Dor Pós-Operatória/tratamento farmacológico , Assistência Centrada no Paciente/normas , Guias de Prática Clínica como Assunto , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Prescrições de Medicamentos/estatística & dados numéricos , Feminino , Humanos , Tempo de Internação/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Transtornos Relacionados ao Uso de Opioides/etiologia , Transtornos Relacionados ao Uso de Opioides/prevenção & controle , Manejo da Dor/normas , Manejo da Dor/estatística & dados numéricos , Medição da Dor/estatística & dados numéricos , Dor Pós-Operatória/diagnóstico , Alta do Paciente/normas , Padrões de Prática Médica/normas , Padrões de Prática Médica/estatística & dados numéricos , Estudos Retrospectivos , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: A majority of surgical patients are prescribed opioids for pain management. Many patients have pre-existing chronic pain managed with opioids and/or opioid use disorders (OUDs), which can complicate perioperative management. Patients who use opioids prior to surgery are at increased risk of developing OUD after surgery. To date, no studies have examined the prevalence of opioid screening and electronic medical record (EMR) documentation prior to surgery. MATERIALS AND METHODS: A 40-item survey was administered to 268 patients at their first postoperative care visit at a single tertiary academic center from October 2017 to July 2018. A chart review of a random sample of 100 patients was performed to determine provider opioid screening prevalence in the presurgical setting. Log-binomial models were used to calculate prevalence ratios (PRs) to determine the provider role (surgeon, advanced practice clinicians [APC], surgical trainee) association with opioid screening documentation. Exploratory qualitative interviews were conducted with surgical providers to identify barriers to screening and screening documentation. RESULTS: Only 7% of patients were screened preoperatively for opioid use. A total of 38% of patients self-reported that they had used opioids in the past year. Of that group, only 3% had screening by a surgical provider prior to surgery documented in their EMR. Provider role was not associated with likelihood of opioid screening (surgeon versus trainee, PR = 1.2, 95% CI 0.2-8.5) (surgeons versus APCs, PR = 1.05, 95% CI 0.17-8.53). EMRs were discordant with patient survey results for patients with no ICD-10 codes for opioid use. The most common perceived barriers to preoperative screening were insufficient clinic time; logistics of who should screen/not required as part of their clinical workflow; not perceiving screening as a priority; and lack of expertise in the area of chronic opioid use and OUD. CONCLUSIONS: Preoperative screening for opioid use is uncommon, and EMRs are often discordant with patient self-reported use. Efforts to increase preoperative screening will need to address barriers screening practices and increasing health system support by incorporating screening into the clinical workflow and adding it to documentation templates.
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Analgésicos Opioides/efeitos adversos , Programas de Rastreamento/estatística & dados numéricos , Transtornos Relacionados ao Uso de Opioides/diagnóstico , Dor Pós-Operatória/tratamento farmacológico , Procedimentos Cirúrgicos Operatórios/efeitos adversos , Adulto , Idoso , Dor Crônica/tratamento farmacológico , Registros Eletrônicos de Saúde/estatística & dados numéricos , Feminino , Humanos , Masculino , Programas de Rastreamento/organização & administração , Programas de Rastreamento/normas , Pessoa de Meia-Idade , Epidemia de Opioides/prevenção & controle , Transtornos Relacionados ao Uso de Opioides/epidemiologia , Transtornos Relacionados ao Uso de Opioides/prevenção & controle , Manejo da Dor/efeitos adversos , Manejo da Dor/métodos , Dor Pós-Operatória/etiologia , Guias de Prática Clínica como Assunto , Padrões de Prática Médica/organização & administração , Padrões de Prática Médica/normas , Padrões de Prática Médica/estatística & dados numéricos , Cuidados Pré-Operatórios/métodos , Cuidados Pré-Operatórios/normas , Cuidados Pré-Operatórios/estatística & dados numéricos , Estudos Prospectivos , Medição de Risco/métodos , Medição de Risco/estatística & dados numéricos , Autorrelato/estatística & dados numéricos , Cirurgiões/normas , Cirurgiões/estatística & dados numéricos , Fluxo de TrabalhoRESUMO
BACKGROUND: Postoperative overprescribing is common, and many patients will have excess medications. An effective method to encourage disposal is lacking. We hypothesized that a convenient home disposal kit will result in more appropriate disposal of excess opioids. MATERIALS AND METHODS: We conducted a single-center prospective observational pilot study to evaluate the effectiveness of a postoperative opioid disposal kit. Patients in the intervention group received an opioid disposal kit and educational handout before discharge from the hospital. At the first follow-up visit, patients completed a survey in which they reported the remaining amount of pain medications from their original prescription and their plan for the excess medication. Patients were asked about risk factors for chronic opioid use. We used multivariable Poisson regression to identify independent factors associated with an increased likelihood of appropriate opioid disposal. RESULTS: The survey was offered to 904 patients with a response rate of 91.7%. After excluding those with missing data, 571 patients were included in the study. Overall, 83 (14.5%) patients never filled an opioid prescription, and 286 (60.0%) patients had tablets remaining at the time of the follow-up visit. Among those with tablets remaining, 52 received a home disposal kit, whereas 234 patients with tablets remaining did not. Patients who received the kit were more likely to dispose of opioid medications (54.9% versus 34.8%, relative risk = 1.8, 95% CI 1.3-2.5). No confounders were identified during multivariable analysis that increased a patient's likelihood of disposing excess medications. CONCLUSIONS: The provision of a convenient home disposal kit postoperatively increased patient-reported opioid disposal.
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Analgésicos Opioides , Prescrições de Medicamentos/estatística & dados numéricos , Eliminação de Resíduos/estatística & dados numéricos , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Inquéritos e QuestionáriosRESUMO
Complexes of copper and 1,10-phenanthroline have been utilized for organic transformations over the last 50 years. In many cases these systems are impacted by reaction conditions and perform best under an inert atmosphere. Here we explore the role the 1,10-phenanthroline ligand plays on the electronic structure and redox properties of copper coordination complexes, and what benefit related ligands may provide to enhance copper-based coupling reactions. Copper(II) triflate complexes bearing 1,10-phenanthroline (phen), ([Cu(phen)2(OTf)]OTf, 1) and oxidized derivatives of phen including [Cu(edhp)2](OTf)2 (2), [Cu(pdo)2](OTf)2 (3), [Cu(dafo)2](OTf)2 (4) were prepared and characterized. X-ray crystallographic data show these related ligands subtly impacted the coordination geometry of the copper(II) ion. Complexes 1-3 had only incremental changes to the redox properties of the copper ions, complex 4 showed a drastically different redox potential affording a remarkably air stable copper(I) complex. These complexes 1-4 were then used to catalyze the C-N bond forming cross coupling between imidazole and various boronic acid substrates, where the increased stability of the copper(I) species in complex 4 appears to better support these CEL cross couplings.
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INTRODUCTION: The incidence of venous thromboembolism in children has increased significantly over the past 20 years. Over the same period of time, there was an increase in the prevalence of obesity in the pediatric population. Obesity is a known risk factor for VTE in adults, but little information is available in children. METHODS: This study evaluates the relation between obesity and VTE using a retrospective, case-control design, comparing the body mass index (BMI) of patients admitted with a diagnosis of VTE versus patients admitted with other diagnoses, at a single institution, between 2007 and 2011. RESULTS: We studied 48 inpatients diagnosed with deep venous thrombosis or pulmonary embolism and a control group of 274 age and gender matched patients admitted with other diagnoses. We found obese patients (BMI > 95th percentile) to have significantly higher risk of VTE (odds ratio 2.1, with 95% CI 1.1-4.2) than patients of normal weight (BMI < 85th percentile). Overweight patients (BMI 85th-95th percentile) did not demonstrate a significant change in risk. Most of the VTE patients were adolescents and the majority of them had other identifiable risk factors for thrombosis. CONCLUSION: This study establishes a correlation between obesity and VTE in a group of hospitalized children, showing a risk for VTE in obese children similar to the one described in much larger adult cohorts.
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Pacientes Internados , Obesidade , Tromboembolia Venosa , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Obesidade/complicações , Obesidade/epidemiologia , Fatores de Risco , Fatores Sexuais , Tromboembolia Venosa/epidemiologia , Tromboembolia Venosa/etiologiaRESUMO
In the title mol-ecular salt, C22H22O2P(+)·PF6 (-), the side chain of the cation adopts an anti-gauche conformation [P-C-C-C and C-C-C-C torsion angles = -179.11â (10) and -77.18â (16)°, respectively]. In the crystal, the cations are linked into carb-oxy-lic acid inversion dimers by pairs of O-Hâ¯O hydrogen bonds. Weak C-Hâ¯F and C-Hâ¯(F,F) hydrogen bonds connect the components into a three-dimensional network, but there are no aromatic π-π stacking inter-actions.
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Objective: Hepatobiliary tumors have evolving management guidelines. Patient educational needs and interest in community engagement are unknown. This study serves as a needs assessment. Methods: A prospective, needs assessment, survey study of hepatobiliary patients was performed (2016-2019). Surveys (n = 169) were distributed covering three domains of interest: informational needs, interest in outreach, and engagement preferences. Results: Seventy patients completed the survey (response rate = 41.4%). Most patients had completed surgical treatment (84.3%). Cancer treatment was ranked as their primary topic of interest (n = 39, 55.7bold%), followed by symptom management, nutrition, and survivorship. Most patients did not participate in screening (n = 57, 81.4%), though were interested in learning more about these programs. Thirty-nine patients (55.7%) stated they would want to receive more education. Only 17 (24.3%) were interested in attending in-person events. Patients preferred online methods for education (n = 49, 70%). While patients were aware of their case presentation at tumor board, only 38 (54.3%) felt well-informed about recommendations. Conclusion: Multidisciplinary care is complex and difficult for patients to navigate. Most patients have interest in educational resources and prefer online modalities. Patients understand multidisciplinary tumor boards, but communication could be improved. Innovation: These data inform a new, innovative, approach to outreach efforts in this population.
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A series of tridentate copper(II) N-heterocyclic carbene (NHC) complexes with imidazole, benzimidazole, and 5,6-dimethylbenzimidazole azole rings were synthesized and comprehensively characterized via X-ray crystallography, ESI-MS, cyclic voltammetry, and UV-Vis and EPR spectroscopic studies. These complexes were then utilized for the optimization of ketone reduction under sustainable conditions using 2-acetylpyridine and phenylsilane. The relationships between product formation, temperature, reaction time, and catalyst loading for the hydrogenation reactions are covered in detail. Reduction of eighteen different aliphatic, cyclic, and aromatic ketones were demonstrated, which were compatible to produce the corresponding products in moderate to good yields. These systems were used to develop related DNA-hybrid catalytic systems, but only supported weak enantioselectivity. Further thermodynamic experiments showed Cu-NHC complexes did not demonstrate specific binding to DNA, which is consistent with their limited selectivity.
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Copper(II) complexes with tridentate NNN-ligands were utilized for Chan-Evans-Lam (CEL) cross-coupling reactions to enable the N-arylation of multifarious N-nucleophiles through the activation of aryl boronic acids. A condition-specific methodology was developed to chemoselectively target the amine versus sulfonamide N-arylation of 4-aminobenzenesulfonamide using new catalysts. Two different pyridine-based ligands and corresponding copper(II) complexes were characterized using 1H and 13C-NMR, FTIR, and UV-vis spectroscopy, HRMS, single-crystal X-ray diffraction, and cyclic voltammetry. Solvent and base-controlled cross-coupling reactions were observed, which led to the optimization of selective conditions for targeted C-N bond formation of sulfanilamides. Beyond the chemoselective processes reported here, a breadth of N-nucleophiles including sulfanilamides and arylamines were screened for arylation by this CEL catalyst.
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Zinc(II) ions play critical roles in all known life as structurally important stabilizing ions in proteins, catalytically active metals in enzymes, and signaling agents impacting physiological changes. To maintain homeostasis, the intracellular concentration of zinc(II) is strictly controlled by a family of metal-regulatory proteins in both prokaryotic and eukaryotic organisms. In S. pneumoniae, there are two proteins that share responsibility for Zn2+ homeostasis, one of them is the Adhesin Competence Repressor (AdcR) and it binds to a specific double-stranded DNA binding domain (dsDNA). AdcR has been structurally characterized containing two zinc(II) metal centers per monomeric unit. Here we report data collected from differential scanning calorimetry (DSC) experiments aimed to measure the structural stability of AdcR, the fully complimented Zn2AdcR complex, and the protein/DNA complex Zn2AdcR/dsDNA. Thermograms collected from DSC experiments yielded endothermic unfolding events for AdcR, Zn2AdcR, and Zn2AdcR/dsDNA complex at 55.6, 70.2, and 56.6 °C, respectively. A non-two state unfolding model best fits the data, giving ΔH terms associated with these thermal unfolding events of 5.1, 7.1, and 4.9 kcal/mol. These data allow for the development of a thermodynamic cycle connecting both zinc(II) and DNA binding to AdcR. Furthermore, pairing this newly reported data with known association constants for zinc(II) and DNA binding allowed for the generation of thermodynamic profiles for both zinc(II) binding to AdcR and Zn2AdcR binding to DNA, which show both are decisively entropy-driven processes.
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DNA , Zinco , Zinco/química , DNA/metabolismo , Adesinas Bacterianas , Ligação Proteica , Streptococcus pneumoniae/química , Streptococcus pneumoniae/genética , Streptococcus pneumoniae/metabolismo , Termodinâmica , Varredura Diferencial de CalorimetriaRESUMO
Molybdenum (Mo) is a naturally-occurring trace element in drinking water. Most commonly, molybdate anions (MoO42-) are in well water and breast milk. In addition, it is used in medical image testing. Recently, the EPA classified Mo as a potential contaminant, as exposure can lead to health effects such as gout, hyperuricemia, and even lung cancer. We have assessed the sorptive removal of aqueous molybdate using Douglas fir biochar (DFBC) and a hybrid DFBC/Fe3O4 composite containing chemically-coprecipitated iron oxide (Fe3O4). Adsorption was studied at various: pH values, equilibrium times (5 min-24 h), initial Mo concentrations (2.5-1000 mg/L), and temperatures (5, 25, and 40 °C) using batch sorption and fixed-bed column equilibrium methods. Langmuir capacities for DFBC and DFBC/Fe3O4 (at pH 3, 2 hrs equilibrium) were within 459.3-487.9 mg/g and 288-572 mg/g, respectively. These adsorbents and their Mo-laden counterparts were characterized by elemental analysis, BET, PZC, SEM, TEM, EDS, XRD, and XPS. MoO42- adsorption on DFBC is thought to be governed primarily via electrostatic attraction. Adsorption by DFBC/Fe3O4 is primarily governed by chemisorption onto magnetite surface hydroxyl groups, while electrostatics prevail in the DFBC-exposed phase. Stoichiometric precipitation of iron molybdates triggered by iron dissolution was also considered. The data suggest that DFBC and DFBC/Fe3O4 are promising candidates for molybdate sorption.
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Pseudotsuga , Poluentes Químicos da Água , Humanos , Molibdênio , Poluentes Químicos da Água/análise , Carvão Vegetal/química , Adsorção , Água/química , Ferro/química , CinéticaRESUMO
Arylboronic acids are commonly used in modern organic chemistry to form new C-C and C-heteroatom bonds. These activated organic synthons show reactivity with heteroatoms in a range of substrates under ambient oxidative conditions. This broad reactivity has limited their use in protic, renewable solvents like water, ethanol, and methanol. Here, we report our efforts to study and optimize the activation of arylboronic acids by a copper(II) N-heterocyclic carbene (NHC) complex in aqueous solution and in a range of alcohols to generate phenol and aryl ethers, respectively. The optimized reactivity showcases the ability to make targeted C-O bonds, but also identifies conditions where water and alcohol activation could be limiting for C-C and C-heteroatom bond-forming reactions. This copper(II) complex shows strong reactivity toward arylboronic acid activation in aqueous medium at ambient temperature. The relationship between product formation and temperature and catalyst loading are described. Additionally, the effects of buffer, pH, base, and co-solvent are explored with respect to phenol and ether generation reactions. Characterization of the new copper(II) NCN-pincer complex by X-ray crystallography, HR-MS, cyclic voltammetry, FT-IR and UV-Vis spectral studies is reported.