Protic acid immobilized on solid support as an extremely eEfficient recyclable catalyst system for a direct and atom economical esterification of carboxylic acids with alcohols

A convenient and clean procedure of esterification is reported by direct condensation of equimolar amounts of carboxylic acids with alcohols catalyzed by an easy to prepare catalyst system of perchloric acid immobilized on silica gel (HClO<SUB>4</SUB>−SiO<SUB>2</SUB>). The direct condensation of aryl, heteroaryl, styryl, aryl alkyl, alkyl, cycloalkyl, and long-chain aliphatic carboxylic acids with primary/secondary alkyl/cycloalkyl, allyl, propargyl, and long-chain aliphatic alcohols has been achieved to afford the corresponding esters in excellent yields. Chiral alcohol and N-t-Boc protected chiral amino acid also resulted in ester formation with the representative carboxylic acid or alcohol without competitive N-t-Boc deprotection and detrimental effect on the optical purity of the product demonstrating the mildness and chemoselectivity of the procedure. The esters of long-chain (>C<SUB>10</SUB>) acids and alcohols are obtained in high yields. The catalyst is recovered and recycled without significant loss of activity. The industrial application of the esterification process is demonstrated by the synthesis of prodrugs of ibuprofen and a few commercial flavoring agents. Other protic acids such as H<SUB>2</SUB>SO<SUB>4</SUB>, HBr, TfOH, HBF<SUB>4</SUB>, and TFA that were adsorbed on silica gel were less effective compared to HClO<SUB>4</SUB>−SiO<SUB>2</SUB> following the order HClO<SUB>4</SUB>−SiO<SUB>2</SUB> ≫ H<SUB>2</SUB>SO<SUB>4</SUB>−SiO<SUB>4</SUB> > HBr−SiO<SUB>2</SUB> > TfOH−SiO<SUB>2</SUB> ≫ HBF<SUB>4</SUB>−SiO<SUB>2</SUB> ≈ TFA−SiO<SUB>2</SUB>. When HClO<SUB>4</SUB> was immobilized on other solid supports the catalytic efficiency followed the order HClO<SUB>4</SUB>−SiO<SUB>2</SUB> > HClO<SUB>4</SUB>−K10 > HClO<SUB>4</SUB>−Al<SUB>2</SUB>O<SUB>3</SUB> (neutral) > HClO<SUB>4</SUB>−Al<SUB>2</SUB>O<SUB>3</SUB> (acidic) > HClO<SUB>4</SUB>−Al<SUB>2</SUB>O<SUB>3</SUB> (basic)

Sputum smear and culture conversion in multidrug resistance tuberculosis patients in seven districts of central Gujarat, India: A longitudinal study

Objectives: To know the sputum smear and culture conversion among multidrug resistance tuberculosis (MDR-TB) patients. Materials and Methods: The longitudinal cohort study was conducted for 142 MDR-TB patients registered in 2010 under Revised National Tuberculosis Control Programme of Vadodara region. Three follow-ups were taken for sputum and culture examination, at completion of 6, 12, and 24 months of treatment. Individuals were interviewed to know the reasons for missed dose and default. Results: The sputum smear and culture conversion rate was 43.4%, 47.7%, and 57% at 6 months, 12 months, and 24 months of follow-up, respectively. Treatment default rate was highest (15.2%) within initial 6 months of therapy. The mean time to sputum smear and culture conversion was 120.27 days and 125.02 days, respectively. Conclusions: Most of patients who were culture positive at 6 months remained so even after 12 months. There was not much difference in the time taken for culture and sputum conversion

The prevalence of malocclusion and orthodontic treatment need in 13-15 years old school going children of Mehsana District, Gujarat: An epidemiological study

Aim: The current study's objective was to find out the prevalence of malocclusion and the need for orthodontic treatment in 13- to 15-year-old school students in the Mehsana District of Gujarat using the IOTN. Materials and Methods: A descriptive cross-sectional epidemiological survey was planned among 13- to 15-year-old school-going children of Mehsana district. The sample comprised of 1290 school children. DHC-IOTN was applied to evaluate normative need for orthodontic treatment. Perceived orthodontic treatment was described by the Aesthetic component of the IOTN index. Results: Results showed that 33.7 percent of participants required little/no treatment need, 43.9 percent of participants required moderate orthodontic treatment need, and 22.4 percent of participants required severe orthodontic treatment need in the district. Conclusion: To prepare for public orthodontic and dental services, the current study provides baseline data on the need for orthodontic treatment among school-aged children

Histopathological study of nasal masses in patients coming to a tertiary care hospital: A study of 70 cases

Introduction: Nasal polyps are defined as prolapsed lining of the nasal sinuses. They may be present as simple inflammatory polyps or neoplastic tumors and neoplastic tumors further divided in benign or malignant types. Objectives: This study was undertaken to note the various histopathological patterns of nasal masses, their classification and relative distribution of various lesions with regard to age and sex in our setting. Materials and Methods: in this study, 70 patients are selected who presented in our hospital with nasal masses and having multiple types of clinical presentations. Time period of study is 2 years. Results: Nonneoplastic nasal masses formed the largest group of lesions; 50 cases (71.43%), followed by 20 cases (28.57%) of neoplastic nasal masses, in neoplastic masses we found 14 benign and 6 malignant cases. Conclusion: Nasal obstruction and rhinorrhea are the most common symptoms of presentation, simple inflammatory nasal polyps are the most common histological pattern seen in our environment, and surgery is the best modality of treatment