EVALUATION OF LITHIUM BASED DEICING CHEMICALS FOR MITIGATING ASR IN CONCRETE PAVEMENT

Deicing and anti-icing chemicals such as alkali-acetate and alkali-formate based formulations are increasingly being used on airfield pavements. Among these new deicers, potassium acetate-based formulations are widely used due to their environmentally friendly nature and effectiveness in melting and undercutting ice at low temperatures. Recent research on premature deterioration of airfield pavements due to alkali-silica reaction (ASR) has indicated that alkali-acetate and alkali-formate deicers such as potassium acetate and sodium formate may have been responsible for the observed distress. In an effort to develop a deicing chemical that is benign to concrete from an ASR standpoint, a new deicing formulation based on lithium compounds is being explored. This research study presents the findings from a laboratory-based investigation on developing a lithium-acetate based deicing chemical to specifically address ASR concern in concrete. In these studies, mortar bars and concrete prism specimens were prepared with aggregates of known reactivity and exposed to solutions of pure lithium acetate and pure potassium acetate at different concentrations. In addition, parallel tests were conducted on mortar bars and concrete prisms in which test specimens were exposed to solution blends of lithium acetate and potassium acetate at different Li/K molar ratios (Li/K molar ratios=0.2, 0.4, 0.6, 0.8). Also, in order to evaluate the effect of these deicing chemicals on scaling resistance of concrete, modified ASTM C 672 tests were conducted. In order to understand the extent of externally applied damage in concrete, the K+ ion and Li+ ion profiles were established using Inductively Coupled Plasma (ICP) and X-Ray Fluorescence spectrometer (XRF) techniques. Also, tests were conducted to determine the effectiveness of lithium nitrate, when applied as a pre-treatment before exposing to potassium acetate to find its effect in mitigating ASR. Results from this study showed that specimens containing reactive aggregates and soaked in blends of lithium acetate and potassium acetate showed little or no expansion due to alkali-silica reactivity. It is also observed that potassium acetate deicer at concentration levels of 3 and 6.4 plays a significant role in the expansion of mortar bars and concrete prisms. No scaling was observed in concrete slabs made with both reactive and non-reactive aggregate exposed to 3 and 6.4 molar KAc solutions. From the penetration test, the gradient from top to bottom showed the influence of K in concrete samples. Mortar bars which were pre-treated with LiNO3 showed significantly lesser expansion compared to bars which were not treated, upon exposure to potassium acetate deicers. In general, specimens made with high-alkali cement expanded more, compared to specimen made with low-alkali cement. It is recommended that lithium blended deicers with at least Li/K ratio of 0.2 be used for mitigating ASR. Also, low-alkali cements should be preferred when exposure to deicers is anticipated

Influence of affective response at the end of exercise on future exercise choice in low-active, overweight participants

PURPOSE: Approximately 35-50% of individuals who start an exercise program have been reported to drop-out within the first few months (e.g., Dishman & Buckworth, 1997). Suggestions have been made that affective experience of exercise is linked to adherence, but only a limited amount of research has been conducted in this area. Also, none of these studies measured the influence of affective experiences during exercise on future choice. Identifying exercise that results in a positive affective experience may increase adherence. A theory that has found support in other fields is the Peak-End hypothesis (Kahneman et al., 1993). It suggests that individuals\u27 positive affective experience and subsequent decisions about a behavior are derived from the peak affective moment and the final moments while engaged in the behavior. An episode with a pleasurable peak at the end will be remembered as positive even if it is longer than another episode with no pleasurable peak at the end (a concept known as Duration Neglect) Therefore, the purpose of this study was to determine whether adding a positive end to an unpleasant exercise bout will influence the choice to repeat an exercise bout and to test whether exercise duration plays a role in this choice. METHODS: 27 overweight and low-active young adults (14 males, mean age 26 yrs) completed an incremental treadmill exercise test to determine ventilatory threshold (VT). They then completed two counterbalanced exercise sessions: one at 10% above VT for 20 minutes and one at 10% above VT for 20 minutes followed by 2.5 mph, 0% grade for 5 minutes. Given that exercising above VT has been shown to elicit predominantly negative responses and exercising below VT elicits a positive affective response, these workloads were designed to result in a peak negative end affect and a peak positive end affect, respectively. Feeling Scale scores were measured before, during, and after exercise in both the sessions. In a final session, participants were asked to choose to repeat one of the two exercise bouts. RESULTS: Participants were twice as likely to choose to repeat the exercise bout that ended positively over the one that ended negatively, even though it was longer and involved more work overall. CONCLUSION: The results support the Peak-End and Duration neglect hypotheses in an exercise setting. To promote adherence, exercise prescriptions should put emphasis on a pleasurable (i.e. reduced intensity) end to each exercise bout

TRACKING THE ORGANOLEPTIC AND BIOCHEMICAL CHANGES IN THE AYURVEDIC POLYHERBAL AND NATIVE FERMENTED TRADITIONAL MEDICINES: BALARISHTA AND CHANDANASAVA

Objective: Ayurvedic formulary contains fermented polyherbal medicines which includes Balarishta and Chandanasava. The changes occurring in the successive stages of fermentation of these medicines are least understood such as organoleptic and biochemical parameters.Methods: The samples were collected from a manufacturing unit. The sensory evalution of color, smell, touch and taste was carried out. Biochemical estimations, GC-MS analysis, estimation of aflatoxins and heavy metals were performed.Results: The native fermentation led to browning with herbal odouration and sour taste in both Balarishta and Chandanasava preparations. pH was drastically reduced to acidic in Balarishta when compared to Chandanasava. Total solids drastically reduced in Chandanasava than in Balarishta. In both medicament fermentations, total sugar gradually decreased with concomitant increase in ethanol. Formation of acetic acid, gradual decrease in aminoacid and starch contents signify the fermentation process. Both Balarishta and Chandanasava were devoid of methanol, aflatoxins and heavy metals like mercury, lead and cadmium.Conclusion: Preparation of Ayurvedic fermented medicines exemplified by Balarishta and Chandanasava are earmarked with major changes in organoleptic and biochemical parameters and are found safe by the absence of toxic components assessed. Â

Optimising perinatal outcome in fetal growth restriction using doppler velocimetry

INTRODUCTION: Ante partum fetal surveillance is the corner stone of preventive obstetric management aimed at reducing maternal and perinatal mortality and morbidity. Ante partum detection of fetus at risk of death or compromise in utero remains the major challenge in modern obstetrics. Specific and accurate methods for detection of fetus at risk can result in early appropriate intervention and hence reduce fetal loss. Diagnostic ultrasound is the main stay in the evaluation and management of obstetric patients. Antenatal test of fetal well being depends indirectly on changes in fetal physiology, an aspect of fetus, which until recently, has been relatively inaccessible to study. There has been a paucity of techniques to measure the placental function - the critical organ through which the transfer of nutrients occur. Fetal growth and development rely on normal uteroplacental and fetoplacental circulation to supply oxygen and nutrients from the maternal circulation. New technologies have now become available in the clinical assessment of placental function. Doppler ultrasound offers a non - invasive evaluation of the feto-placental circulation and can identify placental circulatory failure. There are specific abnormalities in Doppler parameters in asymmetric intrauterine growth retardation, which occurs as a result of utero - placental insufficiency . Hence doppler ultrasound plays a key role in antenatal fetal surveillance of high risk pregnancies like evaluation of growth restricted fetuses. AIMS AND OBJECTIVES: 1. To detect any abnormalities in fetoplacental unit and fetal circulation in IUGR. 2. To identify the hypoxemic fetus & time the delivery before the occurrence of acidemia. 3. To correlate the occurrence of adverse perinatal outcome with degree of abnormality in doppler indices. MATERIALS AND METHODS This study was conducted jointly at the Institute of Obstetrics and Gynecology and Barnard Institute of Radiology, Chennai both coming under the Madras Medical College, Chennai. Two hundred documented IUGR cases confirmed by clinical evaluation and serial ultrasound biometry were selected for the study and it was done on singleton pregnant women with welldocumented period of gestation beyond 34 weeks. Known congenital anomalies were excluded from the study. The machine used for Doppler was an Aloka 3500 color Doppler machine with a 3.5 to 5 MHz curvilinear probe. Name, Age, Unit, Registration number and Address of the patients were noted. Detailed obstetric history including the history of pregnancy induced hypertension; gestational diabetes and chronic hypertension were obtained. History of previous pregnancies including birth weight of previous babies, perinatal deaths, and mode of delivery were elicited. Details of present pregnancy were asked, including the date of last menstrual period, details of scan in the first trimester and clinical examination noting, if available, were scrutinized. SUMMARY: Diagnosis of IUGR was done by clinical assessment and serial sonography. • The routine use of SFH measurement together with the use of serial ultrasound examinations in the 3rd trimester of high risk pregnancies detected majority of IUGR cases. • With the use of Doppler of umbilical and middle cerebral arteries, it is possible to predict that an IUGR fetus is not hypoxic. • With ductus venosus alteration, detection of fetal acidemia is possible. • Negative predictive value of normal Doppler is 100%. It means that if the Doppler is normal in an IUGR fetus the possibility of an abnormal perinatal outcome is very rare. So, unnecessary intervention can be reduced in those pregnancies with normal Doppler and normal amniotic fluid volume. • There is a strict co-relation between abnormal umbilical Doppler velocimetry and an increased incidence of perinatal complications in an IUGR fetus. • Incidence of perinatal mortality and morbidity are increased with the worsening of Doppler velocimetry. • In cases with absent and reversed diastolic flow in umbilical artery the perinatal morbidity is nearly100%. • The perinatal mortality in cases of ductus venosus alteration is 100%. • In cases with differential shunting of blood flow to the fetal brain, frequent monitoring and early delivery should be done. • The Doppler ultrasound finding of increased resistance of umbilical artery and decreased resistance of middle cerebral artery, detects the fetus at risk of complications 2 weeks earlier than the conventional methods like NST. • After identifying those fetuses at risk of complications, close monitoring is done by non stress test and bio-physical scoring for planning the delivery so as to improve the perinatal outcome. • Since ductus venosus has been shown to cause irreversible fetal compromise and inevitably leads to fetal demise, close monitoring should be done so as to deliver before the fetus becomes acidotic which is shown by the increase in ductus PI values. CONCLUSIONS: The diagnosis of utero-placental insufficiency causing fetal growth restriction identifies a group of fetuses who are prone for perinatal complications. • Many fetuses with FGR are hypoxemic and some are acidemic even prior to the onset of labor. • The role of antenatal surveillance is identification of the hyproxemic fetus, since the sequelae of hypoxemia can only be altered by iatrogenic intervention. Delivery is timed to precede acidemia. • Doppler ultrasound velocimetry is a noninvasive, repeatable and simple method for antepartum fetal surveillance which holds great promise in this area. • There is a strong correlation between fetal hypoxemia and Doppler measured flow indices of the fetal arterial and venous circulations. • Grading of the Doppler abnormalities can accurately predict the perinatal outcome of the potentially compromised FGR baby much earlier than NST and thus it can be used as a prognostic tool as proved in our study. • So, Doppler ultrasound should be used in all patients with fetal growth restriction, to identify impending hypoxia, to optimise the time of delivery, and hence to optimise the perinatal outcome in these patients

Discrete modeling of shape memory alloys

Ph.DDOCTOR OF PHILOSOPH

Comparison of growth and conversion efficiency of the freshwater prawn Macrobrachium malcolmsonii (H. Milne Edwards) juveniles fed with formulated and commercial feeds

A nutritional study was carried out to know the feasibility of formulated and commercial feeds on the growth of juveniles of the freshwater prawn Macrobrachium malcolmsonii. Best relative growth rate was observed for feed 1 followed by feeds 2 and 3. Animals fed with feed 1 showed higher production than the other feeds. Higher assimilation efficiency was noticed in the animals provided with feeds 5 and 4. Higher gross and net growth efficiencies were observed in the animals offered feed 1. Among the commercial feeds, feed 3 may considered to be suitable alternative to feed 1

IN SILICO PROBING OF ANTI-ARTHRITIC POTENTIAL OF TRADITIONALLY FERMENTED AYURVEDIC POLYHERBAL PRODUCT BALARISHTA REVEALS LUPEOL AND DESULPHOSINIGRIN AS EFFICIENT INTERACTING COMPONENTS WITH UREC

Objective: To assess the anti-arthritic properties of Balarishta, an Ayurvedic fermented poly herbal product used to combat the immunological disorder, Rheumatoid Arthritis which is an autoimmune disease triggered by Proteus urinary tract infection through in silico analysis and assay of antimicrobial activity. Methods: Antibacterial activity of Balarishta against Proteus mirabilis was assessed. Phytochemical analysis was performed by Gas Chromatography-Mass Spectroscopy. Urease interaction proteins were homology modeled based on template constraints and physicochemical parameters and stereo chemical nature of the proteins were analyzed. Rigid and flexible docking was done to study the hydrogen bond interaction patterns between active ingredients of Balarishta and urease interaction proteins. Results: In Balarishta, 42 bioactive metabolites were identified by Gas Chromatography-Mass Spectroscopy analysis. These metabolites were checked for strong binding affinities against urease subunits and urease accessory proteins of Proteus mirabilis in silico. ureC subunit exhibited high binding to the compound desulphosinigrin (-10.5217 Kcal/mol) followed by lupeol (-10.0308 Kcal/mol) with conserved residue interaction ranging from amino acid residues 308 – 327. Further, lupeol when bound to ureC had 4 hydrogen bonds as compared to desulphosinigrin with 6 hydrogen bonds. Free energy calculations based on flexible docking showed that lupeol had significant binding affinity for ureC with -9.2 Kcal/mol rather than -6.0 Kcal/mol for desulphosinigrin. Both binding has residue conservation - Cys 319, His 320 and His 321. The results corroborated with in vitro antibacterial activity. Conclusion: It is proposed that Balarishta would be efficient in arresting Rheumatoid Arthritis complicated urinary tract infections