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1.
Sci Rep ; 14(1): 10189, 2024 05 03.
Article in English | MEDLINE | ID: mdl-38702352

ABSTRACT

The study aimed to determine the accuracy of diagnosing periodontal conditions using the developed web-based PocketPerio application and evaluate the user's perspective on the use of PocketPerio. First, 22 third-year dental students (DS3) diagnosed ten cases without PocketPerio (control) and with PocketPerio (test) during a mock examination. Then, 105 DS3, 13 fourth-year dental students (DS4), and 32 senior second-year International Standing Program students (ISP2) used PocketPerio chairside. Statistical analysis was performed using a non-parametric paired two-tailed test of significance with the Wilcoxon matched-pairs signed rank test. The null hypothesis that PocketPerio did not increase the accuracy of periodontal diagnoses was rejected at α < 0.01. Periodontal diagnoses made using PocketPerio correlated with those made by periodontics faculty ("gold standard") in all cases. During the mock examination, PocketPerio significantly increased the accuracy of periodontal diagnoses compared to the control (52.73 vs. 13.18%, respectively). Chairside, PocketPerio significantly increased the accuracy of primary (100 vs. 40.0%) and secondary (100 vs. 14.25%) periodontal diagnoses compared to the respective controls. Students regardless of their training year felt more confident in diagnosing periodontal conditions using PocketPerio than their current tools, provided positive feedback on its features, and suggested avenues for its further development.


Subject(s)
Periodontal Diseases , Students, Dental , Humans , Periodontal Diseases/diagnosis , Periodontics/education , Education, Dental/methods , Female , Male , Software
2.
J Periodontol ; 2024 Apr 11.
Article in English | MEDLINE | ID: mdl-38605536

ABSTRACT

BACKGROUND: Periodontal diseases (PD) have been increasingly associated with several systemic conditions such as cardiovascular disease (CVD), diabetes mellitus (DM), rheumatoid arthritis (RA), and Alzheimer's disease (AD). This study aimed to gain insight into patients' awareness of the association between PD and systemic diseases. METHODS: A survey was developed to analyze patient awareness of the association between PD and systemic diseases. Descriptive and categorical variables were summarized with counts and percentages. Chi-squared tests were used to evaluate differences between variables. A linear logistical regression model was used to assess the simultaneous, independent association between each variable. RESULTS: Data from 161 completed surveys were analyzed. The majority of the participants (61.49%) reported awareness of symptoms of PD, but only 36.36% identified all its major symptoms. Individuals reporting awareness of the association between PD and systemic diseases was 48.4%, 31.7%, 14.9%, and 9.9% for CVD, DM, RA, and AD, respectively. Patients aged ≥51 years and males were more aware of the association between PD and CVD. Increased awareness of an association between PD and DM was observed among patients who had a higher frequency of dental visits and those with a self-reported history of DM. CONCLUSIONS: This study provides insight that, even with the vast amount of scientific knowledge on the inter-relationships that exist between PD and systemic diseases, most patients are still unaware of these associations. This research identified that improvement of health literacy surrounding PD, their symptoms, and their association with systemic diseases may be warranted.

3.
J Diabetes Complications ; 37(7): 108494, 2023 07.
Article in English | MEDLINE | ID: mdl-37209505

ABSTRACT

AIMS: This cross-sectional analysis explored the relationships between periodontal disease (PD) and subclinical CVD in a cohort of patients with type 1 diabetes and non-diabetic controls. METHODS: Data were collected from adults enrolled in the Coronary Artery Calcification in Type 1 Diabetes (CACTI) study or enrolled through the Barbara Davis Center for Diabetes Adult Clinic. A clinical periodontal exam measured attachment loss and probing depth. Brachial artery distensibility (brachD), carotid intima-media thickness (cIMT), and pulse wave velocity (PWV) were assessed as measures of subclinical cardiovascular structure and function. RESULTS: 144 participants with T1D and 148 non-diabetics were enrolled. Compared to non-diabetic controls, T1D participants had a higher probing depth (2.6 mm vs. 2.5 mm; p = 0.04), higher attachment loss (2.7 mm vs. 2.4 mm; p < 0.01), lower brachD (mean 5.8 vs. 6.4 mmHg; p < 0.01), a higher cIMT (mean 0.68 vs. 0.64 mm; p < 0.01), and a higher PWV (mean 8.3 vs. 7.8 m/s; p < 0.01). There were no significant associations between PD and CVD metrics. CONCLUSIONS: Periodontal and cardiovascular health was worse in participants with T1D compared to non-diabetics. No significant associations between PD measures and CVD were identified.


Subject(s)
Cardiovascular Diseases , Diabetes Mellitus, Type 1 , Periodontal Diseases , Periodontitis , Adult , Humans , Diabetes Mellitus, Type 1/complications , Diabetes Mellitus, Type 1/epidemiology , Cross-Sectional Studies , Risk Factors , Carotid Intima-Media Thickness , Cardiovascular Diseases/complications , Cardiovascular Diseases/epidemiology , Pulse Wave Analysis , Heart Disease Risk Factors , Periodontal Diseases/complications , Periodontal Diseases/epidemiology
4.
Sci Transl Med ; 15(684): eabq8476, 2023 02 22.
Article in English | MEDLINE | ID: mdl-36812347

ABSTRACT

Periodontal disease is more common in individuals with rheumatoid arthritis (RA) who have detectable anti-citrullinated protein antibodies (ACPAs), implicating oral mucosal inflammation in RA pathogenesis. Here, we performed paired analysis of human and bacterial transcriptomics in longitudinal blood samples from RA patients. We found that patients with RA and periodontal disease experienced repeated oral bacteremias associated with transcriptional signatures of ISG15+HLADRhi and CD48highS100A2pos monocytes, recently identified in inflamed RA synovia and blood of those with RA flares. The oral bacteria observed transiently in blood were broadly citrullinated in the mouth, and their in situ citrullinated epitopes were targeted by extensively somatically hypermutated ACPAs encoded by RA blood plasmablasts. Together, these results suggest that (i) periodontal disease results in repeated breaches of the oral mucosa that release citrullinated oral bacteria into circulation, which (ii) activate inflammatory monocyte subsets that are observed in inflamed RA synovia and blood of RA patients with flares and (iii) activate ACPA B cells, thereby promoting affinity maturation and epitope spreading to citrullinated human antigens.


Subject(s)
Arthritis, Rheumatoid , Periodontal Diseases , Humans , Autoantibodies , Mouth Mucosa , Antibody Formation , Epitopes , Bacteria
5.
Article in English | MEDLINE | ID: mdl-35353093

ABSTRACT

Identifying the accurate location of the greater palatine artery (GPA) can be challenging. The purpose of the present cadaver study was to determine the location of the GPA from the cementoenamel junction (CEJ) of the maxillary canine to second molar teeth and to define its relationship with the palatal vault height (PVH) in Caucasian cadavers. Sixty-six sections from fully or partially dentate cadavers were examined. The location of the GPA from the CEJ ranged from a minimum of 8.7 ± 2.1 mm at the canine to 14.5 ± 1.3 mm at the second molar. The minimum distance of the GPA to the CEJ in different PVH ranged from 6 to 12 mm. There was a significant difference between male and female cadavers regarding shallow PVH. Only the PVH as an independent variable had a significant correlation with the GPA location. The present study is the first to identify the different PVHs with customized stents and to correlate them with the distance of the GPA to the CEJ of maxillary teeth.


Subject(s)
Arteries , Palate , Arteries/anatomy & histology , Cadaver , Female , Humans , Male , Molar , Palate/blood supply , Tooth Cervix
6.
Early Interv Psychiatry ; 15(3): 739-741, 2021 06.
Article in English | MEDLINE | ID: mdl-32436347

ABSTRACT

AIM: This paper aims to examine how existing mental health within the city of Chennai, India manages first-episode psychosis, to determine lacunae and barriers in providing effective early intervention and to make appropriate recommendations to improve the care of first-episode psychosis patients. METHODS: Interviews were held with 15 health professionals to capture information on current practices and facilities available for the management of first-episode psychosis. RESULTS: No specialized clinic or services were available for individuals with first-episode psychosis in Chennai, except one. Pharmacotherapy was the main treatment modality with psychological support to patients and families. Most common drugs used were Risperidone, Olanzapine, and Haloperidol in their recommended doses. General practitioners and paediatricians, due to inadequate training in mental health, referred patients with psychosis to mental health professionals. CONCLUSIONS: Equipping the existing mental health services to manage FEP and training all health professionals on psychosis will improve FEP management in Chennai.


Subject(s)
Psychotic Disorders , Haloperidol , Humans , India , Olanzapine , Psychotic Disorders/diagnosis , Psychotic Disorders/drug therapy , Risperidone
7.
Early Interv Psychiatry ; 15(3): 716-722, 2021 06.
Article in English | MEDLINE | ID: mdl-32436369

ABSTRACT

BACKGROUND: India has a large youth population whose mental health needs must be addressed. This includes promotion of positive mental health, with early detection and effective intervention for mental health disorders. Understanding the perspectives of community stakeholders working with youth is pivotal to this effort. Current study aimed to bring together a group of community stakeholders (eg, parents, teachers, policy makers) to understand their perspectives on youth mental health problems, challenges in provision of care, and to provide recommendations to address these concerns at national level. MATERIALS AND METHODS: The study was conducted across two sites in India: Chennai and New Delhi. Three group meetings were conducted involving 52 participants, including governmental, non-governmental and community representatives working with youth. The proceedings were manually recorded, transcribed, and analyzed using thematic analysis method. RESULTS: Many youth mental health problems were similar across the two sites. The commonest drivers of mental health problems were reported to be academic pressure, substance use and problematic internet/social media use. Stigma and lack of awareness were identified as the most important challenges acting as barriers to seeking mental health help by youth. Prioritizing youth mental health as a national programmes along with strong political will were the major recommendations suggested by the stakeholders. CONCLUSION: Initial findings suggest that prioritizing youth mental health programmes in India would be advantageous. Inclusive and collaborative approach, involving community stakeholders working with youth in providing services that promote mental health and early access to care will help in developing healthy young citizens.


Subject(s)
Mental Health Services , Substance-Related Disorders , Adolescent , Humans , India , Mental Health , Social Stigma
10.
Gen Dent ; 67(2): 34-37, 2019.
Article in English | MEDLINE | ID: mdl-30875305

ABSTRACT

Injury to the contents of the mental foramen (MF) can be minimized by using cone beam computed tomography (CBCT) to determine the exact location of the MF prior to surgical procedures. In this retrospective study, variations in the vertical position of the MF between adult men and women older than 18 years were investigated using CBCT. The distance between the superior border of the MF and the most apical aspect of the cementoenamel junction (CEJ) of the mandibular second premolar was measured. Among the randomly accessed CBCT records of 200 patients, 176 MF-CEJ measurements met the inclusion criteria. There was a statistically significant difference (P < 0.001) between the sexes in the location of the MF. The distance in women was shorter by an average of 2.00 mm, irrespective of the side of the mandible. Additionally, a within-sex asymmetry between right and left sides was observed; the asymmetry was significantly greater in men than in women (P < 0.05). Clinicians should be cognizant of the influence of the patient's sex on the vertical position of the MF and the presence of asymmetry in the position of the MF between the right and left sides of the mandible within the sex groups.


Subject(s)
Cone-Beam Computed Tomography , Tooth Cervix , Adult , Bicuspid , Cone-Beam Computed Tomography/methods , Female , Humans , Male , Mandible , Retrospective Studies , Tooth Cervix/diagnostic imaging
11.
J Oral Maxillofac Surg ; 76(12): 2525-2531, 2018 12.
Article in English | MEDLINE | ID: mdl-30509393

ABSTRACT

PURPOSE: In the United States, 2.1 million people develop substance abuse disorders that are associated with prescribed opioids. The objective of the present study was to identify the factors associated with opioid abuse and dependence (OAD) in those hospitalized for head and neck cancer (HNC). Although measures are being implementing to reduce opioid prescribing, the use of these drugs in individuals with HNC can be valuable. However, little is known about OAD among this cohort of individuals. MATERIALS AND METHODS: The present study was a retrospective analysis of the Nationwide Inpatient Sample for 2012 to 2014. All patients hospitalized because of any HNC were selected. The OAD prevalence was identified. The patient demographic, hospital, and geographic factors were considered independent variables and OAD was the outcome. Multivariable logistic regression model was used to identify the factors associated with OAD. RESULTS: A total of 92,055 patients were hospitalized because of HNCs. OAD was prevalent in 0.8% of the patients. The OAD rates were greatest in patients with a malignant neoplasm of ill-defined sites within the lip, oral cavity, and pharynx (1.6%). Age 30 to 44 years (odds ratio [OR] 5.19, 95% confidence interval [CI] 2.23 to 12.06; P < .01) and age 45 to 64 years (OR 4.05, 95% CI 2.15 to 7.61; P < .01) were associated with greater odds for OAD compared with age older than 64 years. Black (OR 1.76, 95% CI 1.12 to 2.78; P = .01) and Hispanic (OR 2.20, 95% CI 1.27 to 3.79; P < .01) race/ethnicity were associated with greater odds for OAD compared with white race/ethnicity. Individuals covered by Medicaid (OR 2.08, 95% CI 1.26 to 3.43; P < .01), and those who were uninsured (OR 2.27, 95% CI 1.05 to 4.89; P = .04) were associated with greater odds for OAD compared with those covered by private insurance. An increase in the comorbid burden was associated with increased odds of OAD (OR 1.57, 95% CI 1.47 to 1.68; P < .001). CONCLUSIONS: The present study identified specific anatomic sites where malignant neoplasm was associated with greater odds of OAD. Additionally, the study found that coverage by Medicaid, black and/or Hispanic race/ethnicity, lowest income households, and a greater comorbid burden were associated with greater odds of OAD.


Subject(s)
Analgesics, Opioid/adverse effects , Head and Neck Neoplasms/drug therapy , Opioid-Related Disorders/etiology , Adolescent , Adult , Aged , Aged, 80 and over , Analgesics, Opioid/therapeutic use , Child , Comorbidity , Databases, Factual , Female , Head and Neck Neoplasms/epidemiology , Head and Neck Neoplasms/psychology , Hospitalization , Humans , Logistic Models , Male , Middle Aged , Opioid-Related Disorders/diagnosis , Opioid-Related Disorders/epidemiology , Prevalence , Retrospective Studies , Risk Factors , Socioeconomic Factors , United States/epidemiology , Young Adult
12.
J Investig Clin Dent ; 9(4): e12354, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30066389

ABSTRACT

AIM: Opioid abuse/dependence (OAD) is an emerging public health crisis in the USA. The aim of the present study was to estimate the nationwide prevalence of OAD in those hospitalized due to periapical abscess in the USA. METHODS: The Nationwide Inpatient Sample for 2012-2014 was used. All patients who were hospitalized due to periapical abscess were selected for analysis. In this cohort, OAD was identified and used as the outcome variable. A mix of patient and geographic factors were used as independent variables. The simultaneous association between outcome and independent variables was examined by a multivariable logistic regression model. Clustering of outcomes within hospitals was adjusted. Odds of OAD were computed for all independent variables. RESULTS: During the study period, 30 040 patients were hospitalized due to periapical abscess; 1.5% of these had OAD. Those aged 18-29 years (odds ratio [OR] = 3.69, 95% confidence interval [CI] = 1.76-7.72, P < 0.01) and 30-44 years (OR = 3.19, 95% CI = 1.77-5.76, P < 0.01) were associated with higher odds for OAD compared to those aged 45-64 years. Blacks were associated with lower odds for OAD compared to whites (OR = 0.52, 95% CI = 0.28-0.95, P = 0.03). Those covered by Medicare (OR = 4.08, 95% CI = 1.458-11.44, P = 0.01), Medicaid (OR = 5.86, 95% CI = 2.22-15.47, P < 0.01), and those who were uninsured (OR = 3.68, 95% CI = 1.30-10.45, P = 0.01) were associated with higher odds for OAD compared to those covered by private insurance. The odds of OAD increased with comorbid burden (OR = 1.66, 95% CI = 1.50-1.84, P < 0.01). CONCLUSIONS: High-risk groups that are likely to have OAD were identified among those hospitalized due to periapical abscess.


Subject(s)
Opioid-Related Disorders/complications , Periapical Abscess/etiology , Adolescent , Adult , Age Factors , Aged , Female , Hospitalization/statistics & numerical data , Humans , Insurance Coverage/statistics & numerical data , Insurance, Health/statistics & numerical data , Male , Middle Aged , Opioid-Related Disorders/epidemiology , Risk Factors , United States/epidemiology , Young Adult
13.
J Dent Educ ; 81(1): 14-21, 2017 Jan.
Article in English | MEDLINE | ID: mdl-28049673

ABSTRACT

The aim of this study was to analyze dental students' descriptions of and reflections on the periodontal care they provided for their patients in dental school clinics. All students enrolled in the final year of the DDS program in 2011-14 at the University of Colorado School of Dental Medicine were required to complete a self-assessment of the periodontal care they provided for patients. Assessments from 263 students were compiled and qualitatively analyzed. The key reasons given for not providing good care were identified and then stratified as student/school-dependent or patient-dependent factors. Among these students, 63.1% reported that the periodontal care they provided for their patients was inadequate. Some of the student/school-dependent factors were multiple providers involved in patient care (22.8%), student oversight (21.3%), licensure and academic requirements (20.9%), limited clinic operator sessions (19.4%), clinical rotations to other sites (18.3%), and students' interest in/emphasis on other areas of dentistry (17.9%). Some of the patient-dependent factors were patient scheduling compliance (61.6%), patient finances (46.4%), medical status (20.5%), urgent dental needs (18.3%), emphasis only on restorative care (17.5%), periodontal care awareness (16.4%), and patients' oral hygiene compliance (11.5%). This analysis of students' attitudes, challenges they faced, and patient-related factors that influenced the delivery of periodontal care helped to facilitate changes in the curriculum and school policies to optimize clinical instruction and patient care in periodontics.


Subject(s)
Periodontal Diseases/therapy , Quality of Health Care , Schools, Dental/standards , Students, Dental , Attitude of Health Personnel , Colorado , Female , Humans , Male , Patient Compliance/statistics & numerical data , Self-Assessment
14.
J Periodontol ; 84(3): 389-95, 2013 Mar.
Article in English | MEDLINE | ID: mdl-22612367

ABSTRACT

BACKGROUND: Periodontitis can ultimately result in tooth loss. Many natural and synthetic materials have been tried to achieve periodontal regeneration, but the results remain variable and unpredictable. We hypothesized that exogenous treatment with dentin matrix protein 1 (DMP1) activates specific genes and results in phenotypic and functional changes in human periodontal ligament stem cells (hPDLSCs). METHODS: hPDLSCs were isolated from extracted teeth and cultured in the presence or absence of DMP1. Quantitative polymerase chain reactions were performed to analyze the expression of several genes involved in periodontal regeneration. hPDLSCs were also processed for immunocytochemical and Western blot analysis using phosphorylated extracellular signal-regulated kinase (pERK) and ERK antibodies. Alkaline phosphatase and von Kossa staining were performed to characterize the differentiation of hPDLSCs into osteoblasts. Field emission scanning electron microscopic analysis of the treated and control cell cultures were also performed. RESULTS: Treatment with DMP1 resulted in the upregulation of genes, such as matrix metalloproteinase-2, alkaline phosphatase, and transforming growth factor ß1. Activation of ERK mitogen-activated protein kinase signaling pathway and translocation of pERK from the cytoplasm to the nucleus was observed. Overall, DMP1-treated cells showed increased expression of alkaline phosphatase, increased matrix, and mineralized nodule formation when compared with untreated controls. CONCLUSION: DMP1 can orchestrate a coordinated expression of genes and phenotypic changes in hPDLSCs by activation of the ERK signaling pathway, which may provide a valuable strategy for tissue engineering approaches in periodontal regeneration.


Subject(s)
Extracellular Matrix Proteins/physiology , MAP Kinase Signaling System/drug effects , MAP Kinase Signaling System/genetics , Mitogen-Activated Protein Kinases/metabolism , Osteoblasts/drug effects , Periodontal Ligament/drug effects , Phosphoproteins/physiology , Cell Differentiation/drug effects , Cells, Cultured , Enzyme Activation/drug effects , Extracellular Matrix Proteins/pharmacology , Gene Expression Regulation, Developmental , Humans , Periodontal Ligament/cytology , Periodontal Ligament/enzymology , Phosphoproteins/pharmacology , Phosphorylation , Protein Transport , Recombinant Proteins , Regeneration/genetics , Stem Cells/drug effects
15.
FASEB J ; 23(11): 3851-64, 2009 Nov.
Article in English | MEDLINE | ID: mdl-19638401

ABSTRACT

It is becoming increasingly evident that histone deacetylases (HDACs) have a prominent role in the alteration of gene expression during the growth remodeling process of cardiac hypertrophy. HDACs are generally viewed as corepressors of gene expression. However, we demonstrate that class I and class II HDACs play an important role in the basal expression and up-regulation of the sodium calcium exchanger (Ncx1) gene in adult cardiomyocytes. Treatment with the HDAC inhibitor trichostatin A (TSA) prevented the pressure-overload-stimulated up-regulation of Ncx1 expression. Overexpression of HDAC5 resulted in the dose-dependent up-regulation of basal and alpha-adrenergic stimulated Ncx1 expression. We show that Nkx2.5 recruits HDAC5 to the Ncx1 promoter, where HDAC5 complexes with HDAC1. Nkx2.5 also interacts with transcriptional activator p300, which is recruited to the Ncx1 promoter. We demonstrate that when Nkx2.5 is acetylated, it is found associated with HDAC5, whereas deacetylated Nkx2.5 is in complex with p300. Notably, TSA treatment prevents p300 from being recruited to the endogenous Ncx1 promoter, resulting in the repression of Ncx1 expression. We propose a novel model for Ncx1 regulation in which deacetylation of Nkx2.5 is required for the recruitment of p300 and results in up-regulation of exchanger expression.


Subject(s)
Histone Deacetylases/physiology , Myocytes, Cardiac/metabolism , Sodium-Calcium Exchanger/metabolism , Animals , Cats , E1A-Associated p300 Protein/metabolism , Histone Deacetylase 1/metabolism , Histone Deacetylases/metabolism , Homeobox Protein Nkx-2.5 , Homeodomain Proteins/metabolism , Hydroxamic Acids/pharmacology , Male , Mice , Myocytes, Cardiac/drug effects , Promoter Regions, Genetic/physiology , Rats , Sodium-Calcium Exchanger/drug effects , Transcription Factors/metabolism , Transcriptional Activation , Up-Regulation
16.
Biotechnol Bioeng ; 94(3): 554-64, 2006 Jun 20.
Article in English | MEDLINE | ID: mdl-16528758

ABSTRACT

Although lipases are known to catalyze alkoxycarbonylation reactions in organic solvents, the existing knowledge base on their substrate specificity in alkoxycarbonylation reaction is sparse. Moreover, models to predict substrate specificity have not been reported. Here, we report the experimentally measured rate constants for 180 acyl donor-alcohol pairs and demonstrate the two-step synthesis of over 70 disubstituted carbonate products from simple precursors such as diphenyl carbonate and alcohols. The efficiency of synthesis was found to be dependent on the order of alcohol addition. This motivated the need to develop a model to predict lipase specificity in alkoxycarbonylation reactions. A partial least square model has been developed to correlate the reaction rate with (i) descriptors of alcohol for a fixed acyl donor, (ii) descriptors of acyl donor for a fixed alcohol, (iii) descriptors of both the acyl donor and the alcohol. The number of descriptors being far greater than the number of observations was a potential limitation in the model development. This was addressed by selecting a subset of descriptors using a systematic procedure based on (a) correlation among the descriptors and step-wise regression methodology, and (b) variable influence on projection methodology. The model was able to accurately predict the reaction rate and the optimal order of addition of alcohols in the two-step synthesis of disubstituted carbonates using the enzyme mixture. The descriptor subset and the relevant model would benefit the users of lipases in synthetic applications while the modeling strategy presented here can have applications in predicting specificity of other enzymes.


Subject(s)
Bacterial Proteins/chemistry , Burkholderia cepacia/enzymology , Candida/enzymology , Fungal Proteins/chemistry , Lipase/chemistry , Models, Chemical , Alcohols/chemistry , Solvents/chemistry , Substrate Specificity , Vinyl Compounds/chemistry
17.
Biotechnol Prog ; 19(2): 332-7, 2003.
Article in English | MEDLINE | ID: mdl-12675568

ABSTRACT

Lipase-catalyzed alkoxycarbonylation methods offer potential advantages over the currently practiced industrial scale chemical synthesis of carbonates. We report a method for synthesis of organic carbonates via lipase-catalyzed alkoxycarbonylation between diphenyl carbonate and various alcohols in hexane. This method utilizes precursors that are readily available and does not involve extensive purification of the intermediate. In a two-step process, the two phenyl groups of diphenyl carbonate were substituted by two alcohol nucleophiles. The approach was demonstrated for two-step synthesis of 14 different disubstituted carbonate products. The rates of reaction for the two steps were much slower if the order of nucleophile addition was reversed. Under optimal conditions, complete conversion of diphenyl carbonate occurred within 8-15 h at 50 degrees C, which is a significant improvement from 50-90 h at 24 degrees C. A kinetic model for the alkoxycarbonylation reaction was derived based on the Michaelis-Menten equation, which simplified to first-order kinetics at low and equimolar concentration of substrates.


Subject(s)
Alcohols/chemistry , Carbonates/chemical synthesis , Hexanes/chemistry , Lipase/chemistry , Lipase/classification , Models, Chemical , Carbon Monoxide/chemistry , Carbonates/chemistry , Computer Simulation , Enzyme Activation , Enzyme Stability , Substrate Specificity , Temperature
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