320 research outputs found
Gold catalysis for selective oxidation for application to bio-derived substrates
The depletion of fossil resources, the volatility of the oil price market and the urgency to mitigate the effects of climate change have pushed the development in chemical industry for sustainable, energy efficient and economic processes for fine chemical production. Selective oxidation of alcohols using noble metal catalysts is a key catalytic conversion for the production of carbonylic and carboxylic compounds for the chemical, pharmaceutical, automobile or consumer goods industry. Gold based catalysts, in particular, have demonstrated superior performance over commonly employed catalysts or stoichiometric oxidants. Challenges, however, remain to develop not only active and selective catalysts but with a long lifetime for industrial application.
This thesis is based on the study and development of gold based catalyst systems for the selective oxidation of alcohols under mild conditions. The main model compound studied is the selective oxidation of salicyl alcohol to salicyl aldehyde and salicylic acid. Salicyl aldehyde is a very important chemical compound for the production of a range of fine chemicals and chelating compounds with an estimated market capacity of 4000-6000 tonnes/year.
Reactions were carried out in a semi-batch stirred glass reactor under atmospheric pressure using air as oxidant and water as solvent. The setup successfully enabled the direct study of the kinetics and mechanism without influences of mass transport. Studies demonstrated the reaction followed sequential mechanism of first order with the consecutive oxidation of salicyl aldehyde to salicylic acid. The main catalyst system used was gold on powdered activated carbon, prepared by sol-immobilisation using Tetrakis(hydroxymethyl)phosphonium chloride (THPC) as stabiliser. 1wt% Au/C achieved maximum turnover frequency numbers (TOF) of 342 h-1 and selectivities of 79% towards salicyl aldehyde at 100% conversion. The increase in gold loading to 3wt% resulted in a decrease in activity caused by an increased gold particle size. The addition of Pd as second active metal showed the formation of an alloy and a decrease in activity with the increase in Pd amount. The application of the Au/C catalyst system for continuous processing was investigated using gold on granular carbon in a trickle bed reactor.
Base-free selective oxidation of salicyl alcohol was studied via synthesis of MgO dispersed on oxides, in particular hydrotalcites. The basicity, measured by CO2 adsorption capacity, increased with increased loading of MgO. The catalysts showed potential activity, achieving 59% conversion with 90% selectivity towards salicyl aldehyde
Psychological Capital: Gender Differences and its Relationship with Job Involvement
This preliminary study explored the relationship between positive psychological capital and job involvement among 100 male and 32 female officers of armed forces. It was hypothesised that officers with higher levels of PsyCap would also exhibit higher job involvement. The study also aimed to investigate whether gender differences in psycap had any influence on job involvement. Psychological capital questionnaire and job involvement scale were administered on the sample. Data was analysed using descriptive and inferential (Pearson correlation and regression analysis) statistics. It is found there is no evidence in support of gender difference in psycap. Psycap has a role in maintaining the job involvement among male officers. Implications of the findings and suggestions for developing positive behaviours which will be of great value to meet future leadership challenges in light of complex and volatile military situations
Radiation versus paclitaxel chemo radiation in the treatment of locally advanced carcinoma of cervix
Background: Cervical cancer is the most common malignancy among women. Incomplete local control and the appearance of distant disease herald poor survival. Concurrent chemo radiation is recently developing as the preferred modality of treatment. The objective of this study was to compare the effectiveness of concurrent Paclitaxel chemo radiation to that of only radiation in treatment of patients with locally advanced squamous cell cervical cancer.Methods: The study was carried out at JIPMER, Puducherry from October 2005 to October 2010. There were two groups with 25 patients each. Group 1 received only radiation - 4860 cGy EBRT daily in five fractions per week for a total of 27 fractions followed by HDR brachytherapy. Group 2 received 50 mg/m2 of Paclitaxel on all Mondays followed by concurrent radiotherapy. Patients were assessed at 6 months and 1 year after completion of treatment. In October 2010 they were all examined to calculate four year survival and disease free survival rate.Results: A total of 48 patients were analyzed. Complete response rate was 56% in group 1 and 72% in group 2. At the end of four years survival and disease free survival rate in group 1 was 57.9% and 31.6% and in group 2 was 57.1% and 33.3% respectively.Conclusions: Concurrent chemo radiation with Paclitaxel gives promising results and is more effective method than treatment with only radiation
Perception of Job Stress among Fighter Controllers in Indian Air Force
The fighter controllers (FC) are an occupational group who deal with a hectic, difficult and highly demanding job. Their occupation entails high levels of responsibility in terms of shouldering the Air Defence operations. These kinds of duties require them to perform optimally at all times and thus impose high grade of an unambiguous occupational stress. In the present study 38 Fighter Controllers of 4 IAF Stations were administered Organisational Role Stress (ORS) scale, Stress Buster Tool Kit and Holmes & Rahe Stress Scale. It was found that 66 per cent of the participants felt Inter Role Distance as a reason for high graded stress, similarly Role Stagnancy (55 %), Role overload (61 %) and Role Isolation (40 %) have severely affected the sample studied. Stress buster tool kit showed that 34 per cent participants perceived severe service related and workplace related stress. Holmes & Rahe questionnaire reported that a total of 31.6 per cent participants were at 90 per cent risk of developing systemic co-morbidities due to stress. This study reports that Fighter Controllers perceive their role to be less important with little opportunities for growth. A significant finding that emerged and that needs attention is the possibility that 1/3rd of the participants are prone to stress induced illnesses. The role of Aerospace Medicine Specialists in this context is paramount in alleviating stress and enhancing self-esteem in Fighter Controllers
Cell Based Therapy for Chronic Liver Disease: Role of Fetal Liver Cells in Restoration of the Liver Cell Functions
Comparison of oral, vaginal and sublingual misoprostol for induction of labour in premature rupture of membranes after 34 weeks of gestation: a randomized controlled trial
Background: Purpose of this study was to evaluate the efficacy and safety of different routes of administration of misoprostol - 50µg oral, 25µg vaginal and 50µg sublingual for induction of labour in women with premature rupture of membranes after 34 weeks of gestation.Methods: Women admitted to labour ward with premature rupture of membranes (PROM) after 34 weeks of gestation and requiring induction of labour were randomized into three groups. A total of 246 women participated in the study and were assigned to three groups to receive either 50µg oral misoprostol (n=80) or 25µg vaginal misoprostol(n=83) or 50µg sublingual misoprostol (n=83). The doses were repeated 4 hourly till active labour was established or up to a maximum of 4 doses. Patient factors, induction to delivery intervals, maternal side effects and fetal outcomes were noted.Results: The mean induction to active labour interval was not significantly different in the three groups (oral vs vaginal vs sublingual-7.52±4.8 vs 7.75±4.1 h vs 7.68±5.3 h; p=0.93). There was no significant difference in the induction to delivery time interval among the three misoprostol groups (oral vs vaginal vs sublingual - 10.9± 5.9 h vs 11.2±5.0 h vs 11.4±6.6 h; p= 0.88). Spontaneous vaginal delivery rate, instrumental delivery rate and lower segment ceasarean section rates were comparable among the three groups. The number of neonates with APGAR score <7 (low APGAR) at 1 minute of birth was highest in sublingual group and lowest in vaginal group which was statistically significant (oral vs vaginal vs sublingual, 16% vs 7.2% vs 20.5%; p= 0. 04). APGAR score <7 at 5 minutes was not significantly different among the three groups (oral vs vaginal vs sublingual, 4.8% vs 2.4% vs 7.2%; p=0.2). This implies that the need for immediate resuscitation was more in the sublingual group. Neonatal intensive care admission was least in the vaginal group although the difference was not statistically significant. Sublingual group had a higher rate of hyperstimulation and fetal heart rate abnormalities compared to oral and vaginal groups although these parameters did not reach statistical significance.Conclusions: Oral, vaginal and sublingual routes of administration of misoprostol are equally effective for labour induction in women with premature rupture of membranes after 34 weeks with sublingual route having slightly higher incidence of low APGAR scores at one minute for the neonate
Efficacy and safety of intracervical Foley’s in women receiving sublingual misoprostol for induction of labour: a randomized controlled trial
Background: Induction of labour can be carried out by medical or mechanical methods, used alone or in combination. This study is to evaluate the efficacy and safety of intracervical Foley’s in women receiving sublingual misoprostol for induction of labour.Methods: We randomized 230 primi gravidae at ≥37 weeks of gestation, with singleton pregnancy, cephalic presentation requiring induction, with Bishop score ≤4 using block randomization into study and control groups. Both groups received 50 µg sublingual misoprostol every fourth hourly till active labour was achieved or upto a maximum of 6 doses. The study group was induced simultaneously with intracervical Foley catheter.Results: Mean induction to labour interval in study and control groups was 11.191±7.14 hours and 11.758±6.26 hours while mean induction to delivery interval was 17.502±7.93 hours and 18.275±7.66 hours respectively with no significant difference between the groups (p=0.522 and 0.453). More women in study group than in the control (51.3% versus 33.9%) were in active labour within ten hours of induction (p=0.001). Caesarean section rate was 23.5% and 19.1% in study and control groups (p=0.497), the most common indication being foetal distress. Secondary outcomes like foetal heart rate abnormalities, oxytocin requirement were comparable between the two groups. APGAR scores and NICU admission rate were similar in both groups. There was no significant maternal or neonatal morbidity.Conclusions: Though there was no significant reduction in induction to labour or delivery interval with synchronous use of sublingual misoprostol and Foley’s, there was no increase in the complications encountered
Pregnancy outcome in preterm premature rupture of membranes between 24 to 34 weeks of gestation
Background: Preterm premature rupture of membranes (PPROM) is spontaneous rupture of the fetal membranes before 37 completed weeks and before onset of labour which complicates 3-5% of all pregnancies. Studies regarding PPROM in very early gestation are lacking. The primary objective was to assess the maternal and perinatal outcome in preterm premature rupture of membranes and secondary objective was to assess the colonization of group B Streptococci (GBS) and Listeria monocytogenes in patients with PPROM.Methods: This prospective study was performed on 175 antenatal women with PPROM between 24 to 34 weeks of gestation.Results: Majority of women (54.2%) were between 32 to 34 weeks of gestation, 37% were between 28 to 32 weeks of gestation and 7.8% were between 24 to 28 weeks of gestation. About 22 % of women had cervicovaginal infections. The prevalence of group B Streptococci in the study group was 1.2% and no isolates of Listeria. The most common maternal morbidity was puerperal fever (11.4 %). Among newborn babies 87 (55 %) required neonatal intensive care unit (NICU) admission mainly for respiratory distress and prematurity. With each week of increase in gestational age, there is decrease in latency period by 22 hours and duration of NICU stay nearly by one day.Conclusions: From the present study it may be concluded that PPROM is associated with genitourinary infection, puerperal pyrexia and respiratory distress syndrome among neonates. The prevalence of group B Streptococci in antenatal women with PPROM is very low and no Listeria were isolated
Impact of obesity on semen quality in men of infertile couples: a cross-sectional study in a tertiary care centre
Background: Obesity is an emerging problem worldwide. The aim of the study was to determine the association of Body mass index and central obesity with semen parameters in men of infertile couples.Methods: This was a descriptive study conducted in a population that included 219 men of infertile couples who attended the infertility clinic. A detailed history was taken from the participants and measurements of height, weight, waist circumference and hip circumference were done by standard methods. General, systemic and urogenital tract examinations were done. The participants were advised to collect semen specimens and semen was analyzed and various semen parameters were noted based on WHO criteria 2010.Results: Among the overweight and obese men, 12.7% and 20.5% were oligozoospermic respectively. Asthenozoospermia was seen in 21.2% and 25% of overweight and obese men. Among men with waist circumference ≥102 cm, 14.3% had oligozoospermia and 35.7% of men had asthenozoospermia. Around 12.2% of men with a Waist-hip ratio >0.9 had oligozoospermia and 19.8% of them had asthenozoospermia.Conclusions: A significant negative association was seen between WHR and sperm concentration, total sperm count, total progressive motility and total motility were seen to be removed. There was no significant association between WC, BMI and sperm concentration, total sperm count, total progressive motility, and total motility
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