Detection of Ricin in Water Samples using DisposableScreen-printed Electrodes

Ricin is a highly toxic plant toxin, which is extracted from the beans of the castor plant,Ricinus communis. Ricin is thousand times more poisonous than cyanide and thirty times morepotent than nerve gases. The toxin (ricin) could be used to contaminate food or water, causingpanic. Attempts were made for the detection of ricin in water samples by utilising amperometricimmunosensors. Single-use screen-printed electrodes were made using polystyrene and graphite.These electrodes were tested  for  their ability  to detect 1-naphthol which is the product of thereaction between 1-naphthyl phosphate and the enzyme alkaline phosphatase conjugate. Anindirect enzyme-linked immunosorbent assay (ELISA) system was used to detect ricin. First,ricin antigen was incubated on the screen-printed electrode. This was followed by blocking withBSA and incubation with antibody raised against ricin in rabbit. The last step wass the incubationwith anti-antibody of rabbit conjugated to enzyme alkaline phosphatase. This electrode is insertedin an electrochemical cell containing diethanolamine buffer and a potential of 0.4 V wrt referenceelectrode (Ag/AgCl) was applied  using a potentiostat.  Various experiments were carried out  foroptimising the conditions like substrate concentration, amount of antibody raised against ricin,anti-antibody alkaline phosphatase conjugate, and blocking agents. It was found that the responseof amperometric sensor is proportional to the logarithmic of ricin concentration from 100 ng/mlto 3200 ng/ml.  Using traditional methods, it is possible to detect ricin concentration up to 300ng/ml in 18 h, while with amperometric immunosensor, one can detect ricin as low as 40 ng/mlwithin 90 min. The details of making the screen-printed electrodes, characterisation, optimisationof various conditions for the highest sensitivity have been discussed

A prospective study of efficacy of ultrasound guided transversus abdominis plane block for postcesarean analgesia

Background: The ultrasound guided transversus abdominis plane (TAP) block which provides effective analgesia after lower abdominal surgeries including caesarean section. It is a simple and reliable technique. In this prospective, randomized double-blind study, we determined the efficacy of TAP block using 0.25% Bupivacaine and 0.9N Saline with respect to VAS for pain, postoperative Tramadol consumption and post-operative ondansetron usage.Methods: This study was conducted on 100 adult patients of ASA physical status I and II in the   age group of 18 to 40 years undergoing elective lower segment cesarean section under spinal anaesthesia. Study group received TAP block with 0.25% Bupivacaine and control group received 10 ml of 0.9N saline on each side. Patients were analyzed for postoperative pain by pain score (at rest, on movement, on cough) using VAS was recorded at 0, ½, 1, 2, 4, 6, 12 and 24 hours postoperatively. Need for rescue analgesia was assessed by time to first dose of Tramadol requirement and total dose of Tramadol over 24 hours of postoperative period. Ondansetron (4 mg i.v.) was administered whenever nausea score was more than 2 or the patient vomited. All the data was noted using uniform performs.Results: Patients received TAP block with 0.25% Bupivacaine had better pain scores at first hour of postoperative period during rest, cough and movement which was statistically significant (p0.001).Conclusions: TAP block using ultrasound provides substantial reduction in Tramadol consumption, time to first dose of rescue tramadol when compared with control group. This study reinforces the recommendation for TAP as a part of multimodal post-operative analgesic regimen

Ice accumulation rate in Changme-Khangpu glacier, Sikkim

Vertical profiles of 137Cs and 210Pb have been determined in a 9 m column of ice from accumulation zone of Changme-Khangpu glacier in north Sikkim valley. 137Cs activity varies from 4 to 22 dpm/ L. In many samples 210Pb occurs at a level of 20 to 65 dpm/ L which is much higher than the expected fallout value. 137Cs and 210Pb activities correlate well with each other but not with the dust content. Possibility of 210Pb production in the nuclear explosions is discussed. Several peaks appear in the depth profile of 137Cs and 210Pb which can be matched with Chinese atmospheric nuclear explosions with some phase difference if a uniform ice accumulation rate of 0.7 m per year is assumed since 1969

The evolutionary status of the semiregular variable QYSge

Repeated spectroscopic observations made with the 6m telescope of yielded new data on the radial-velocity variability of the anomalous yellow supergiant QYSge. The strongest and most peculiar feature in its spectrum is the complex profile of NaI D lines, which contains a narrow and a very wide emission components. The wide emission component can be seen to extend from -170 to +120 km/s, and at its central part it is cut by an absorption feature, which, in turn, is split into two subcomponents by a narrow (16km/s at r=2.5) emission peak. An analysis of all the Vr values leads us to adopt for the star a systemic velocity of Vr=-21.1 km/s, which corresponds to the position of the narrow emission component of NaI. The locations of emission-line features of NaI D lines are invariable, which point to their formation in regions that are external to the supergiant's photosphere. Differential line shifts of about 10km/s are revealed. The absorption lines in the spectrum of QYSge have a substantial width of FWHM~45 km/s. The method of model atmospheres is used to determine the following parameters: Teff=6250K, lg g=2.0, and microturbulence Vt=4.5km/s. The metallicity of the star is found to be somewhat higher than the solar one with an average overabundance of iron-peak elements of [Met/H]=+0.20. The star is found to be slightly overabundant in carbon and nitrogen, [C/Fe]=+0.25, [N/Fe]=+0.27. The alpha-process elements Mg, Si, and Ca are slightly overabundant [alpha/H]=+0.12. The strong sodium excess, [Na/Fe]=+0.75, is likely to be due to the dredge-up of the matter processed in the NeNa cycle. Heavy elements of the s-process are underabundant relative to the Sun. On the whole, the observed properties of QYSge do not give grounds for including this star into the group of RCrB or RVTau-type type objects.Comment: 29 pages, 8 figures, 4 tables; accepted by Astrophys. Bulleti

Peculiarities and variations in the optical spectrum of the post-AGB star V448Lac=IRAS22223+4327

Repeated observations with high spectral resolution acquired in 1998-2008 are used to study the temporal behavior of the spectral line profiles and velocity field in the atmosphere and circumstellar envelope of the post-AGB star V448Lac. Asymmetry of the profiles of the strongest absorption lines with low-level excitation potentials less 1eV and time variations of these profiles have been detected, most prominently the profiles of the resonance lines of BaII, YII, LaII, SiII. The peculiarity of these profiles can be explained using a superposition of stellar absorption line and shell emission lines. Emission in the (0;1) 5635A Swan band of the C2 molecule has been detected in the spectrum of V448Lac for the first time. The core of the Halpha line displays radial velocity variations with an amplitude ~8 km/s. Radial velocity variations displayed by weakest metallic lines with lower amplitudes, 1-2 km/s, may be due to atmospheric pulsations. Differential line shifts, 0 -- 8 km/s, have been detected on various dates. The position of the molecular spectrum is stationary in time, indicating a constant expansion velocity of the circumstellar shell, Vexp=15.2 km/s, as derived from the C2 and NaI lines.Comment: 19 pages, 8 figures, 1 tabl

In-orbit Performance of UVIT on ASTROSAT

We present the in-orbit performance and the first results from the ultra-violet Imaging telescope (UVIT) on ASTROSAT. UVIT consists of two identical 38cm coaligned telescopes, one for the FUV channel (130-180nm) and the other for the NUV (200-300nm) and VIS (320-550nm) channels, with a field of view of 28 $arcmin$. The FUV and the NUV detectors are operated in the high gain photon counting mode whereas the VIS detector is operated in the low gain integration mode. The FUV and NUV channels have filters and gratings, whereas the VIS channel has filters. The ASTROSAT was launched on 28th September 2015. The performance verification of UVIT was carried out after the opening of the UVIT doors on 30th November 2015, till the end of March 2016 within the allotted time of 50 days for calibration. All the on-board systems were found to be working satisfactorily. During the PV phase, the UVIT observed several calibration sources to characterise the instrument and a few objects to demonstrate the capability of the UVIT. The resolution of the UVIT was found to be about 1.4 - 1.7 $arcsec$ in the FUV and NUV. The sensitivity in various filters were calibrated using standard stars (white dwarfs), to estimate the zero-point magnitudes as well as the flux conversion factor. The gratings were also calibrated to estimate their resolution as well as effective area. The sensitivity of the filters were found to be reduced up to 15\% with respect to the ground calibrations. The sensitivity variation is monitored on a monthly basis. UVIT is all set to roll out science results with its imaging capability with good resolution and large field of view, capability to sample the UV spectral region using different filters and capability to perform variability studies in the UV.Comment: 10 pages, To appear in SPIE conference proceedings, SPIE conference paper, 201