MHODE inversion of potential fields

In this thesis, I describe a nonlinear method to invert potential fields data, based on inverting the scaling function of the potential fields - a quantity that is independent on the source property, that is mass density in gravity case or the magnetic susceptibility in the magnetic case. In this approach no a priori prescription of the density contrast is needed and the source model geometry is determined independently of it. We assume Talwani’s formula and generalize the Multi-HOmogeneity Depth Estimation (MHODE) method to the case of the inhomogeneous field generated by a general 2D source. The scaling function is calculated at different altitudes along the lines defined by the extreme points of the potential fields and the inversion of the scaling function yields the coordinates of the vertices of a multiple source body with complex geometrical shape. Once the geometry is estimated, the source density is automatically computed from a simple regression of the scaling function of the gravity data vs. that generated from the estimated source body with unit density. We solve the above nonlinear problem by the Very Fast Simulated Annealing algorithm. The best performance is obtained when some vertices are constrained by either reasonable bounds or exact knowledge. In the salt-dome case we assumed that the top of the body is known from seismic and we solved for the lateral and bottom parts of the body. We applied the technique on data from three synthetic cases of complex sources and on the gravity anomalies over the Mors salt-dome (Denmark) and the Godavari Basin (India). In all these cases, the method performed very well in terms of both geometrical and source-property definition

Study of fetomaternal outcome in pre-eclampsia at tertiary care centres, South Gujarat

Background: Hypertensive disorders are among the most common medical disorder during pregnancy and continue to be a serious challenge in obstetric practice. It affects about 7-15% of all gestations. In India it accounts for the third most important cause of maternal mortality. Aim if this study was to study the prevalence of pre-eclampsia and feto-maternal outcome in cases of pre-eclampsia. Methods: This was a descriptive observational study conducted over a period from February 2019 to July 2021. This study enrolled 106 cases of pre-eclampsia, cases were selected by inclusion and exclusion criteria, data were entered and analysed by using SPSS version 20. Results: A total of 106 patients were analysed. It was observed that it was more common in age group of 26 to 30 years 51%, 56% were unbooked patients. Maximum number of patients were primigravida 60%, 96% patients were from lower socioeconomic class, 37% patients had normal vaginal delivery, 63% had caesarean delivery. The most common maternal complication was eclampsia (12%), HELLP Syndrome 12%, abruptio occurred in 8% of patients. Maternal mortality occurred in 4 cases. Out of 106 babies 37 (34.93%) babies had normal outcome while 29% (27.35%) had low birth weight, 16 (15.09%) babies were IUGR, 15 (14.5%) babies were IUFD, 7 (6.6%) babies had RDS and 2 (1.8%) babies were stillbirth 40 (44.94%) babies were admitted in NICU. Conclusions: This study concludes that foetal and maternal outcome were markedly affected by pre-eclampsia and also the grave complications were more common in pre-eclampsia. So proper antenatal care, early diagnosis of pre-eclampsia and timely intervention will decrease maternal perinatal morbidity and mortality

Combined effects of hyponatremia and hepatic encephalopathy on inpatient mortality

Introduction and Objectives: Although hyponatremia and hepatic encephalopathy (HE) are known independent predictors of mortality, their combined effect is unknown. We investigated whether the inpatient mortality differed among patients with both hyponatremia and HE compared to those with either hyponatremia or HE alone. Materials and Methods: In this retrospective study, data were extracted from the National Inpatient Sample (NIS) to identify US adults (aged ≥18 years) with cirrhosis between January 1st, 2016, and December 31st, 2017. We analyzed the effects of hyponatremia, HE, or a combination of hyponatremia and HE on inpatient mortality using logistic regression. Results: Among 309,841 cirrhosis-related admissions, 22,870 (7%) patients died during hospitalization. Those with a combination of hyponatremia and HE had higher mortality (14%) than those with HE only (11%), hyponatremia only (9%), and neither hyponatremia nor HE (6%) (p<0.001). When compared to patients without hyponatremia or HE, patients with both hyponatremia and HE had the highest odds (adjusted odds ratio or aOR) of inpatient mortality (aOR 1.90, 95% CI: 1.79 – 2.01) followed by patients with HE only (aOR 1.75, 95% CI: 1.69 – 1.82) and patients with hyponatremia only (aOR 1.17, 95% CI: 1.12 – 1.22). Patients with HE only had 50% higher odds of inpatient mortality when compared to those with hyponatremia only (aOR: 1.50, 95% CI: 1.43 – 1.57). Conclusions: In this nationwide study, the presence of both hyponatremia and HE was associated with higher inpatient mortality than either hyponatremia or HE alone

Synthesis of cairomycin A

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Conformationally restricted peptides: solution conformation of tetra and hepta peptides containing α,β-dehydrophenylalanine residues in alternate positions

Two model peptides containing dehydrophenylalanine, a tetrapeptide 1 (Ac- &#916;<SUP>z</SUP>Phe-Pro-&#916;<SUP>z</SUP>Phe-Ala-OMe) and a heptapeptide 2 (Boc-Gly-&#916;<SUP>z</SUP>Phe-Val-&#916;<SUP>z</SUP>Phe-Ala-&#916;<SUP>z</SUP>Phe-Leu-OMe) have been synthesised and their solution conformations investigated by NMR and circular dichroism techniques. Assignment of amide protons and their involvement in intramolecular hydrogen bonding have been made by solvent and temperature dependence studies. These conformation studies indicate the presence of an incipient 3<SUB>10</SUB>-helix in tetrapeptide 1, with two consecutive &#946;-turns and a right handed 3<SUB>10</SUB>-helix in heptapeptide 2. The results establish the potential of &#916;<SUP>z</SUP>Phe residues to favour 3<SUB>10</SUB>-helical conformations with &#948;<SUP>z</SUP>Phe occupying alternate positions in the peptide. A comparison of solution conformation of analogous peptides containing Aib residue in place of &#916;<SUP>z</SUP>Phe is also presented. These residues appear to induce similar conformation constraints in small peptides

Molecular and crystal structure of a dehydroalanine dipeptide

The molecular and crystal structure of the synthetic, terminally blocked, model dipeptide t-Boc-L-Val-ΔAla-OMe (1) was determined by single-crystal X-ray diffraction. Crystal data for 1 are: C14H24N2O5, hexagonal, space group P65 (no.170), a = 10.8000(2) Å, c = 27.077(2) Å, and Z = 6. The crystal structure was solved by direct methods. The least-squares refinement led to R and Rw values of 0.077 and 0.075, respectively, for 1298 reflections F ≥ 5 σ(F). The conformation of the Val residue is partially extended, while that of ΔAla residue is trans, cis. The N-terminal protecting groups is in the trans, trans disposition