Direct observation of geometric-phase interference in dynamics around a conical intersection.

Conical intersections are ubiquitous in chemistry and physics, often governing processes such as light harvesting, vision, photocatalysis and chemical reactivity. They act as funnels between electronic states of molecules, allowing rapid and efficient relaxation during chemical dynamics. In addition, when a reaction path encircles a conical intersection, the molecular wavefunction experiences a geometric phase, which can affect the outcome of the reaction through quantum-mechanical interference. Past experiments have measured indirect signatures of geometric phases in scattering patterns and spectroscopic observables, but there has been no direct observation of the underlying wavepacket interference. Here we experimentally observe geometric-phase interference in the dynamics of a wavepacket travelling around an engineered conical intersection in a programmable trapped-ion quantum simulator. To achieve this, we develop a technique to reconstruct the two-dimensional wavepacket densities of a trapped ion. Experiments agree with the theoretical model, demonstrating the ability of analogue quantum simulators-such as those realized using trapped ions-to accurately describe nuclear quantum effects.

Interannual variability of internal tides in the Andaman Sea: an effect of Indian Ocean Dipole.

A marginal sea in the north eastern Indian Ocean, the Andaman Sea, has been known for the presence of high-amplitude internal waves since the nineteenth century. In this study, we explored the interannual variations of the internal wave activity in this complex region. We found that the Dipole Mode Index, which represents the Indian Ocean Dipole (IOD), influences the circulation in the Andaman Sea, which in turn impacts its density stratification on interannual scales. Ocean Reanalysis System 5 data (1993-2018) is used to see an increasing trend in the sub-surface stratification, whereas it showed a decreasing trend in the near-surface waters. Numerical model simulations carried out from 2009 to 2018 have shown that the interannual variability in the generation of semidiurnal internal tides is governed by distinct parameters (tidal forcing and stratification) at different sites in different months. Enhanced upwelling (downwelling) is observed during positive (negative) IOD events. Sensitivity experiments conducted between extreme IOD events (2006 and 2016) revealed an increase in internal tide generation from positive IOD to negative IOD. Furthermore, a sharp decrease in local baroclinic dissipation is seen during negative IOD, increasing baroclinic flux into the Andaman Sea. An increase in the strength of positive IOD could lead to enhanced diapycnal mixing due to strong local dissipation, whereas an increase in the intensity of negative IOD could result in amplified propagation of internal waves.

Simulation of diurnal variability in vertical density structure using a coupled model.

The changes in the physical properties of the ocean on a diurnal scale primarily occur in the surface mixed layer and the pycnocline. Price-Weller-Pinkel model, which modifies the surface mixed layer, and the internal wave model based on Garrett-Munk spectra that calculates the vertical displacements due to internal waves are coupled to simulate the diurnal variability in temperature and salinity, and thereby density profiles. The coupled model is used to simulate the hourly variations in density at RAMA buoy (15° N, 90° E), in the central Bay of Bengal, and at BD12 (10.5° N, 94° E), in the Andaman Sea. The simulations are validated with the in-situ observations from December 2013 to November 2014. The primary advantage of this model is that it could simulate spatial variability as well. An integrated model is also tested and validated by using the output of the 3D model to initialize the coupled model during January, April, July, and October. The 3D model can be used to initialize the coupled model at any given location within the model domain to simulate the diurnal variability of density. The simulations showed promising results which could be further used in simulating the acoustic fields and propagation losses which are crucial for Navy operations.

Simulating the unimolecular decomposition pathways of cyclotrimethylnitramine (RDX) : Decomposition pathways of RDX.

Based on the three known proposed pathways for the uni-molecular decomposition of RDX, we have formulated the rate equations. A kinetic Monte Carlo code has been developed and used to simulate the uni-molecular decomposition of RDX based on these equations. The KMC simulations allow one to explore each of the decomposition pathways individually and also the three competing pathways at a specified temperature and pressure. The pressure dependence is incorporated using Lindemann's formalism. The code is validated by reproducing the species evolution along each pathway. Amongst the three proposed pathways, the most likely path of RDX decomposition and the time evolution of various molecular species at different ambient temperatures and pressures are obtained. An analytical model has been developed to reproduce the decomposition pathways, which matches the simulation results.

The lateral "backdoor" approach to open thyroid surgery: A comparative study.

INTRODUCTION: The traditionally taught technique for conventional open thyroidectomy is via a midline splitting of the strap muscles following a skin crease neck incision - midline approach (MA). The lateral "backdoor" approach (LA) uses the same central neck incision but approaches the thyroid gland between the anterior border of sternocleidomastoid (SCM) and strap muscles. This technique is usually reserved for re-do thyroid surgery. We compared the results of the two approaches in patients undergoing conventional thyroidectomy for the first time. METHODS: A case-control study was performed on 90 patients undergoing conventional open thyroidectomy from 2012 to 2014. The first 45 patients underwent MA and subsequent 45 patients underwent LA. All patients were given 10 ml of 1% Marcaine infiltration into the neck incision before closure. Basic demographic data, operative time, incision length, weight of gland, need for transection of strap muscles and complications were recorded. Revision thyroid surgery and minimally invasive thyroid operations were excluded. RESULTS: The demographics, operative timing, gland weight and incisional length showed no significant difference. Post-operative pain was significantly lower in the LA group. 5 patients (11%) in MA group needed horizontal transection of strap muscles to extract large goitres compared to 1 patient (2.2%) in the LA group. No major complications occurred in either group. CONCLUSION: The LA method is as safe as the midline technique with comparable operative time and significantly lower pain scores. It avoids midline separation and suturing of strap muscles and reduces the need for strap muscle transection to removal large goitres.

Impact of urbanization coupled with drought situations on groundwater quality in shallow (basalt) and deeper (granite) aquifers with special reference to fluoride in Nanded-Waghala Municipal Corporation, Nanded District, Maharashtra (India).

Rapid expansion in urbanization and industrialization coupled with recent drought conditions has triggered unplanned groundwater development leading to severe stress on groundwater resources in many urban cities of India, particularly cities like Nanded, Maharashtra. In the quest of tapping drinking water requirement, due to recent drought conditions, people from the city are piercing through entire thickness of shallow basalt aquifers to reach productive deeper granite aquifers. Earlier reports from Nanded and surrounding districts suggest that deeper granite aquifer is contaminated with fluoride (geogenic). The study aimed to find out variations in fluoride concentration in shallow basalt (10-167 m) and deeper granite aquifers (below 167 m) and to find out the relationship between fluoride and other ions. Study suggests that concentration of fluoride in shallow basalt aquifer is within maximum permissible limits of Bureau of Indian Standards and deeper granite aquifer contains as high as 4.9 mg/l of fluoride and all samples from granite aquifers are unfit for human consumption. The groundwater from basalt aquifer is mainly Ca-HCO3-Cl type, and from granite aquifer, it is Ca-Na-Cl type. The correlation plot between F- vs. pH, Na+ and HCO3- shows a positive correlation and an inverse relationship with Ca2+ in both aquifers. As recommendations, it is suggested that granite aquifers should not be tapped for drinking purposes; however, in drought situations, water from this aquifer should be blended with treated surface water before supplying for drinking purposes. Efforts may be made to utilize 1.35 MCM of rainwater from available rooftop, which is sufficient to cater for the needs of ~40,800 people annually. Most effective defluoridation techniques like electrolytic de-fluoridation (EDF), ion exchange and reverse osmosis may be adopted along with integrated fluorosis mitigation measures.

Aquifer wise seasonal variations and spatial distribution of major ions with focus on fluoride contamination-Pandharkawada block, Yavatmal district, Maharashtra, India.

Seasonal variations in groundwater reveal lesser concentrations of major ions except NO3(-) during post-monsoon seasons in shallow aquifers as compared to deeper aquifers. The F(-) concentration from deeper aquifers is high in both seasons and shows a moderate positive relationship with weathering depth and is >5 mg/L in compound lava flow. Groundwater is mainly a Ca-HCO3 type in shallow aquifers and mixed type in deeper aquifers. Fluoride shows a positive correlation with pH, Na(+), HCO3(-) in shallow aquifers and an inverse correlation with Ca(2+) and HCO3(-) from deeper aquifers in both seasons. Approximately 45% of the samples are not suitable for drinking from both aquifers but suitable for irrigation purposes. Rock-water interaction, moderate alkalinity, sluggish movement, and higher residence time are the main causes for high F(-) in deeper aquifers as compared to shallow aquifers. As recommendations, drinking water requirement may be met from shallow aquifers/surface water and fluoride rich groundwater for other purposes. Most effective defluoridation techniques like ion exchange and reverse osmosis may be adopted along with integrated fluorosis mitigation measures and rooftop rainwater harvesting. Supplementary calcium and phosphorous rich food should be provided to children and creating awareness about safe drinking water habits, side effects of high F(-), and NO3(-) rich groundwater, improving oral hygiene conditions are other measures.

Polymorphisms in the serum- and glucocorticoid-inducible kinase 1 gene are associated with blood pressure and renin response to dietary salt intake.

Serum- and glucocorticoid-inducible kinase 1 (SGK1) has a central role in epithelial sodium channel (ENaC)-dependent Na(+) transport in the distal nephron. We hypothesized that SGK1 gene variants may contribute to the effect of dietary salt intake on blood pressure (BP) in humans with hypertension, and consequentially influence renin-angiotensin-aldosterone (RAA) system activity. Our study population included 421 hypertensive Caucasian participants of the HyperPath group who had completed a dietary salt protocol with measurement of BP and RAA system activity. Three SGK1 tagging single nucleotide polymorphisms (SNPs) from the HapMap CEU population captured the genetic variation in the SGK1 region. Assuming an additive genetic model, two SNPs (rs2758151 and rs9402571) were associated with BP and plasma renin activity (PRA) effects of dietary salt intake. Major alleles were associated with higher systolic BP on high salt and decreased PRA on low salt. In contrast, low salt neutralized genotype differences. Similar, non-significant trends were observed in a normotensive population (N=152). Genotype was also associated with two salt-sensitive subtypes of hypertension. SGK1 genetic variants are associated with salt sensitivity of BP and PRA in human hypertension. Genotype status at these SGK1 variants may identify individuals prone to salt-sensitive hypertension.

The Bioenteric Intragastric Balloon (BIB) as a treatment for obesity: poor results in Asian patients.

INTRODUCTION: The Bioenteric Intragastric Balloon (BIB, Inamed Health, Santa Barbara, CA, USA) is an endoscopic method for achieving restriction of gastric intake in obese patients. It is less invasive and cheaper than bariatric surgery, but can only be left in the stomach for six months. We report our experience with the BIB in Singapore. METHODS: Since its introduction to our hospital in 2004, a prospective database has been kept of all patients undergoing BIB insertion. This database was used to retrieve the information for this study. RESULTS: 20 patients have undergone BIB insertion. Mean patient age was 40 (range, 28-52) years and 85 percent were female. Mean body weight was 79.6 (range, 67.6- 103.7) kg. Mean body mass index (BMI) was 31.5 (range, 27.8-38.8) kilogramme per square metre. Mean excess weight was 21.2 (range, 11.9-37.6) kg. The BIBs were inserted under conscious sedation. BIB intolerance was a major problem and four patients (20 percent) required early BIB removal due to refractive nausea and epigastric discomfort. All remaining BIBs were removed after six months under conscious sedation. The mean maximum weight loss during the six months was 5.9 (range, 1.4-13.4) kg. The mean maximum percentage of excess weight lost was 32.4 (range, 6.7-87). Weight loss was reasonably preserved at the end of the sixmonth period, but by one year, when all the patients had been without BIBs for at least six months, the mean weight loss for the group compared to pre-BIB weight was only 1.5 kg (range, weight gain 5.3 kg to weight loss 9 kg). The mean percentage excess weight loss at one year was 10.9 (range, 15.1 percent weight gain to 31.3 percent weight loss). Only four patients (20 percent) regarded their experience with the BIB as a success. CONCLUSION: The BIB is poorly tolerated by Asian patients, even when lower volumes are inserted into the balloon to compensate for the smaller Asian stature. Although temporary weight loss can be achieved, mandatory removal of the BIB at six months results in regain of the lost weight in the majority of patients. Eligible patients (BMI 32.5 and above) should be encouraged to undergo bariatric surgery rather than BIB to achieve long-term reliable weight loss. Patients who are ineligible for bariatric surgery may benefit from BIB, especially if they have severe comorbidities and have failed to lose weight by any other means in a validated weight management programme, but the chance of long-term success is poor.

Laparoscopic adjustable gastric banding for severe obesity.

INTRODUCTION: Severe obesity is an increasing problem in Singapore. Laparoscopic adjustable gastric banding (LAGB) was introduced at our hospital in 2001 as part of a comprehensive weight management programme. To assess the effectiveness of this procedure, our results to date have been reviewed. METHODS: A prospective database was kept of all patients undergoing LAGB and this was used to retrieve the information. RESULTS: 256 consecutive patients underwent LAGB from January 2001 up to December 2005. There were 163 females and 93 males, with a median age of 36 years (range 18-63 years). Median preoperative weight was 112.7 kg (range 71.5-204 kg) and median body mass index (BMI) was 41.9 (range 32-73). Three patients were converted from laparoscopic to open laparotomy (1.2 percent). 91 percent of patients were discharged home on the first postoperative day. There were seven hospital morbidities (2.7 percent) with one mortality (0.4 percent). During follow-up, 20 patients (7.8 percent) developed late complications requiring revision surgery. Ten were band complications, requiring revision or removal of the band. The other ten were minor access port or tubing complications. Median weight loss at one year was 27.6 kg (range 5.6-71.2 kg) and median excess weight loss, using a BMI of 23 as a baseline, was 51.7 percent (range 9-117.5 percent). Easily measurable comorbidities such as diabetes mellitus and hypertension improved or resolved in 85.4 percent of patients. CONCLUSION: There is a clear demand for LAGB in Singapore. This has increased since the BMI thresholds for severe obesity were reduced in Asian patients. The surgery provides effective, lasting weight loss with improvement or resolution of comorbidity for most patients. LAGB has the advantages of allowing controlled weight loss and life-long treatment while being easily reversible. When compared to other bariatric surgical procedures, low hospital morbidity has to be offset against the closer follow-up required and the need for secondary surgical procedures in some patients.

Comparative study on glutathione transferases of rat brain and testis under the stress of phenobarbitol and beta-methylcholanthrene.

A comparative study was made on the tissue specific expression of glutathione transferases (GST) in brain and testis after exposure of rat to phenobarbitol (PB) and b-methylcholanthrene (MC). Glutathione transferases, a family of multifunctional proteins are involved in intracellular transport processes and in detoxication of electrophilic xenobiotics by catalyzing reactions such as conjugation, isomerization, reduction and thiolysis. On purification, the yield of GST proteins by affinity chromatography was 39% in testis and 32% in brain. The affinity purified testis GSTs were resolved by chromatofocusing into six anionic and four cationic isozymes, and in brain glutathione transferases were resolved into four anionic and three cationic isozymes, suggesting the presence of multiple isozymes with Yc, Yb, Ybeta and Ydelta in both of them. In testis and brain, these isozymes at identical pI values showed variable functions with a battery of substrates and the cationic isozymes of brain and testis showed identical properties in CHP (cumene hydroperoxide) at pH values of above 7.0. Substrate specificity studies and immunoblot analysis of testis and brain proteins revealed that they play a predominant role in the detoxication of phenobarbitol or beta-methylcholanthrene. Expression of the isozymes in testis and brain on exposure to PB and MC indicated elevated subunit variation. In both testis and brain, Ydelta of pi class was expressed on PB treatment and Yc of alpha class and Ybeta of mu class was expressed in MC treated testis and only Yc was predominantly expressed in MC treated brain. Thus these subunits expression is considered as markers for carcinogenesis and specific to chemical toxicity under phenobarbitol and beta-methylcholanthrene stress.

Is there a difference between right and left femoral bone density?

Because of the known differences in bone mineral density (BMD) of the dominant and nondominant forearms, it has been customary to measure BMD of the nondominant forearm to reduce variance. However, it is less clear whether such systematic differences exist between BMD of the two hips. Accordingly, we measured BMD of both hips and the spine in 131 consecutive white women who presented to a community based private practitioner for evaluation and advice on osteoporosis. There was a highly significant correlation between BMD of the two hips at the femoral neck, trochanter, and Ward's triangle (r = 0.91, 0.93, and 0.89; p < 0.0001 for all three sites), and also between BMD at various measurement sites in the hip and the spine BMD (p < 0.0001). Although, there was no significant difference between the right and left femoral neck BMD, there were small (approximately 1-2.5%) but significant differences between BMD of the two hips at the trochanter and Ward's triangle (p = 0.008 and 0. 005, respectively). The left hip BMD was consistently higher than the right hip BMD at all measurement sites. Because of the small sample size of the left-handed persons, we were unable to determine the influence of dominant handedness on hip BMD. We concluded the following: (1) BMDs of the two hips are highly correlated at relevant measurement sites; (2) there does not appear to be a dominant hip as there is dominant forearm; (3) because of strong agreement between BMD of the two hips there is little justification to measure both hips in routine clinical practice.

Isolation of antioxidant principle from Azadirachta seed kernels: determination of its role on plant lipoxygenases.

An antioxidant principle was isolated from Azadirachta indica seed using high pressure liquid chromatography with a hydrophobic reverse-phase chromatography column. The eluted molecule had lambdamax at 224 and 272 nm and was a potent inhibitor of plant lipoxygenases. In in vivo studies of horsegram during germination, low levels of lipoxygenase activity and lipid peroxides were found upon treatment with the Azadirachta extract. The antioxidant property of Azadirachta indica has not been previously reported.

Anterior communicating artery aneurysms : the direction of aneurysm and its bearing on surgical outcome.

A series of 44 consecutive patients with aneurysms of anterior communicating (A. Com.) artery during an 8 year period, during which 80 patients with 91 aneurysms were operated, is being reported. It comprised 55.0 percent of all aneurysms operated during this period. Eight patients (18.2 percent) had multiple aneurysms. Twenty seven A.Com. aneurysms (61.4 percent) were directed anteroinferiorly, 8 aneurysms (18.2 percent) posterosuperiorly, 6 aneurysms (13.6 percent) superiorly and 3 aneurysms to the side. Twenty nine. A.Com. Aneurysms (65.9 percent) arose at dominant A1-A.Com. junction. All cases were treated by direct surgery. The results are encouraging, though mortality overall was 15.9 percent. Good grade cases made satisfactory recovery. Direction of aneurysm at AC-A.com. and its bearing on surgical outcome is stressed. Most of the posterosuperior pointing aneurysms presented in poorer grades and outcome was unsatisfactory. In comparison most of anteroinferiorly pointing aneurysms presented better grades and results were satisfactory.

Otogenic brain abscess in childhood.

Brain abscesses are quite rare complications of middle ear infections. Although temporal lobe abscesses are more common than cerebellar abscesses, the converse was found to be true in our series of 10 cases. Eight cases of cerebellar abscess and 2 cases of temporal lobe abscess in the paediatric age group were reported including 4 cases of latent brain abscesses which manifested themselves after mastoidectomy for middle ear infection. Brain abscess is by far the most serious of otogenic complications.