Circular dichroism studies of α-aminoisobutyric acid-containing peptides: Chain length and solvent effects in alternating Aib-L-Ala and Aib-L-Val sequences

The CD spectra of the peptides Boc-X-(Aib-X)n-OMe (n = 1, 2, 3) and Boc-(Aib-X)5-OMe, where X = L-Ala or L-Val have been examined in several solvents. The X = Ala and Val peptides behave similarly in all solvents, suggesting that the Aib residues dominate the folding preferences of these peptides. The decapeptides adopt helical conformations in methanol and trifluoroethanol, with characteristic negative CD bands at 222 and 205 nm. In the heptapeptides, similar spectra with reduced intensities are observed. Comparison with nmr studies suggest that estimates of helical content in oligopeptides by CD methods may lead to erroneous conclusions. The pentapeptides yield solvent-dependent spectra indicative of conformational perturbations. Peptide association in dioxane results in an unusual spectrum with a single negative band at 210 nm for the decapeptides. Disaggregation is induced by the addition of methanol or water to dioxane solutions. Aggregation of the heptapeptides is less pronounced in dioxane, suggesting that a critical helix length may be necessary to promote association stabilized by helix dipole-dipole interactions

Comparative Study on the Adsorption Kinetics and Thermodynamics of Metal Ions onto Acid Activated Low Cost Pandanus Carbon

Batch experiments were carried out for the sorption of Copper and Ferrous ions onto acid activated carbon prepared. The operating variables studied were initial metal ion concentration, pH, and temperature and contact time. The equilibrium data were fitted to the Langmuir and Freundlich isotherm equations. From this adsorption efficiency, adsorption energy, adsorption capacity, intensity of adsorption and dimensionless separation factor were calculated. From the kinetic studies the rate constant values for the adsorption process was calculated. From the effect of temperature thermodynamic parameters like ΔG°, ΔH°, and ΔS° were calculated. The mechanism of adsorption for metal ions onto carbon was investigated by using the experimental results and confirmed by FT- IR, XRD and SEM images

A comparative study of feto-maternal outcome in expectant management versus active management in pre-labor rupture of membranes at term

Background: Premature rupture of the membranes at term is spontaneous rupture of the membranes after 37 weeks of gestation and before the onset of the regular painful uterine contractions, complicates 5-10% of pregnancies, 80% of cases of PROM occur at term. It complicates the pregnancy leading to maternal and fetal complications, immediate risks such as cord prolapse, cord compression and placental abruptions, and later risks such as maternal or neonatal infection and the interventions such as caesarean section and instrumental vaginal delivery. These cases are either managed conservatively or by immediate induction of labour. Objective of present study is to compare the efficacy and safety of induction of labor versus expectant management at term PROM, in terms of maternal and fetal outcome.Methods: A randomized control trial of 100 women coming to KIMSH from 01 /04 /2015 to 01 /05 /2016 with PROM at term with duration of leak ≤6 hours and a Bishop score ≤5 were assigned to group A immediate induction group and group B expectant management group with 50 cases in each group.Results: The mean interval from PROM to delivery was significantly shorter in the induction Group 15.62±4.97 as compared with expectant group 17.58±4.78. Incidence of maternal morbidity and neonatal morbidity was comparable in both the groups. Intrapartum complications and mode of delivery were similar in both groups.Conclusions: Immediate induction of labour in cases of PROM at term using oral misoprostol resulted in shorter induction delivery interval and hospital stay. Maternal morbidity and neonatal morbidity was comparable in both groups. It is concluded that immediate induction is better than expectant management. With active management many patients delivered vaginally within 24 hours without increase in the Caesarean section rate and decreased the need for oxytocin augmentation

Effect of land configuration and fertilizer dosage on growth and yield of African marigold under vertic ustochrept soil regimes

Adopting proper land management systems and nutrient levels could improve growth, yield and quality by rendering better soil physical structure and mineral nutrition under heavy rainfall areas. An experiment was conducted to identify appropriate land configuration and fertilizer dose for African marigold var. Punjab Gainda-1, in split plot design with three land configuration methods viz., flat bed, raised bed and ridge & furrow system as main plots, and three fertilizer doses (RDF/ha) viz., 100%, 80% and 60% as subplots with recommended dose of fertilizer (RDF) being 10 t FYM + 150:100:100 kg/ha NPK. Results showed that adopting raised bed method of land configuration with the application of 8 t FYM + 120:80:80 kg/ha NPK exhibited enhanced vegetative growth and flower yield (16.26 t/ha) with greater benefit cost ratio (2.88) and, hence, found economically best for commercial production of African marigold

Spin-ladders with spin gaps: A description of a class of cuprates

We investigate the magnetic properties of the Cu-O planes in stoichiometric Sr$_{n-1}$Cu$_{n+1}$O$_{2n}$ (n=3,5,7,...) which consist of CuO double chains periodically intergrown within the CuO$_2$ planes. The double chains break up the two-dimensional antiferromagnetic planes into Heisenberg spin ladders with $n_r=\frac{1}{2}(n-1)$ rungs and $n_l=\frac{1}{2}(n+1)$ legs and described by the usual antiferromagnetic coupling J inside each ladder and a weak and frustrated interladder coupling J$^\prime$. The resulting lattice is a new two-dimensional trellis lattice. We first examine the spin excitation spectra of isolated quasi one dimensional Heisenberg ladders which exhibit a gapless spectra when $n_r$ is even and $n_l$ is odd ( corresponding to n=5,9,...) and a gapped spectra when $n_r$ is odd and $n_l$ is even (corresponding to n=3,7,...). We use the bond operator representation of quantum $S=\frac{1}{2}$ spins in a mean field treatment with self-energy corrections and obtain a spin gap of $\approx \frac{1}{2} J$ for the simplest single rung ladder (n=3), in agreement with numerical estimates.Comment: 21 pages, 5 figures upon request, REVTEX, ETH-TH/93-3

Effect of land configuration and fertilizer dosage on growth and yield of African marigold under vertic ustochrept soil regimes

Adopting proper land management systems and nutrient levels could improve growth, yield and quality by rendering better soil physical structure and mineral nutrition under heavy rainfall areas. An experiment was conducted to identify appropriate land configuration and fertilizer dose for African marigold var. Punjab Gainda-1, in split plot design with three land configuration methods viz., flat bed, raised bed and ridge & furrow system as main plots, and three fertilizer doses (RDF/ha) viz., 100%, 80% and 60% as subplots with recommended dose of fertilizer (RDF) being 10 t FYM + 150:100:100 kg/ha NPK. Results showed that adopting raised bed method of land configuration with the application of 8 t FYM + 120:80:80 kg/ha NPK exhibited enhanced vegetative growth and flower yield (16.26 t/ha) with greater benefit cost ratio (2.88) and, hence, found economically best for commercial production of African marigold

Density Matrix Renormalization Group Study of the Spin 1/2 Heisenberg Ladder with Antiferromagnetic Legs and Ferromagnetic Rungs

The ground state and low lying excitation of the spin 1/2 Heisenberg ladder with antiferromagnetic leg ($J$) and ferromagnetic rung ($-\lambda J, \lambda >0$) interaction is studied by means of the density matrix renormalization group method. It is found that the state remains in the Haldane phase even for small $\lambda \sim 0.02$ suggesting the continuous transition to the gapless phase at $\lambda = 0$. The critical behavior for small $\lambda$ is studied by the finite size scaling analysis. The result is consistent with the recent field theoretical prediction.Comment: 11 pages, revtex, figures upon reques

Synthesis of magnetic activated carbon from Citrus hystrix (Kaffir lime or Kolumichai) leaves with excellent Pb(II) adsorption performance towards electroplating wastewater

The adsorption behaviour of Pb(II) ions from aqueous solution has been successfully tested by magnetic activated carbon prepared from novel adsorbent such as Citrus hystrix leaves (MCHLAC) by co-precipitation method and followed by thermal activation. The optimum contact time for the removal Pb(II) ions onto MCHLAC is found to be 90 min, and the optimum pH ranged from 5.0–7.0 respectively. The functionality, surface morphology and elemental composition of MCHLAC have been explored by FTIR, SEM and EDX analysis. The equilibrium data agree well with Langmuir model, which confirm the monolayer coverage of Pb(II) ions onto MCHLAC and the maximum monolayer adsorption capacity is 345.65 mg g-1. The kinetic data follow by pseudo-second order model with film diffusion process. Thermodynamic studies indicate that the process of uptake of lead(II) ions is spontaneous and exothermic. A single –stage batch adsorber is designed using the Langmuir adsorption isotherm equation. The regeneration study show that MCHLAC could be effectively utilized for the removal of Pb(II) ions for seven cycles of operation

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