Innovative Technique of Vascular Repair in Intra-Operative IVC Rupture During Lumbar Microdiscectomy: A Case Report

Background: Major vascular injury during a spinal surgery is a rare but most dreaded complication. Case Presentation: A 39 years old female undergoing microscopic lumbar discectomy suddenly developed severe hypotension on table. The procedure was abandoned and the patient turned supine. It was diagnosed to be a major vessel tear and the patient was taken up for immediate successful vascular repair. To best of our knowledge such a repair procedure has not been described in literature. Conclusions: Majority of such vascular injuries are dealt with primary repair of the defect by a vascular surgeon; however in our case the rent was big and placed on the undersurface making it very difficult for the vascular surgeon to approach or repair it primarily

Optical Limiting in Single-walled Carbon Nanotube Suspensions

Optical limiting behaviour of suspensions of single-walled carbon nanotubes in water, ethanol and ethylene glycol is reported. Experiments with 532 nm, 15 nsec duration laser pulses show that optical limiting occurs mainly due to nonlinear scattering. The observed host liquid dependence of optical limiting in different suspensions suggests that the scattering originates from microbubbles formed due to absorption-induced heating.Comment: 10 pages, 5 eps figures, to appear in Chem. Phys. Let

Circular-Polarization Dependent Cyclotron Resonance in Large-Area Graphene in Ultrahigh Magnetic Fields

Using ultrahigh magnetic fields up to 170 T and polarized midinfrared radiation with tunable wavelengths from 9.22 to 10.67 um, we studied cyclotron resonance in large-area graphene grown by chemical vapor deposition. Circular-polarization dependent studies reveal strong p-type doping for as-grown graphene, and the dependence of the cyclotron resonance on radiation wavelength allows for a determination of the Fermi energy. Thermal annealing shifts the Fermi energy to near the Dirac point, resulting in the simultaneous appearance of hole and electron cyclotron resonance in the magnetic quantum limit, even though the sample is still p-type, due to graphene's linear dispersion and unique Landau level structure. These high-field studies therefore allow for a clear identification of cyclotron resonance features in large-area, low-mobility graphene samples.Comment: 9 pages, 3 figure

Resonant hyper-Raman scattering in spherical quantum dots

A theoretical model of resonant hyper-Raman scattering by an ensemble of spherical semiconductor quantum dots has been developed. The electronic intermediate states are described as Wannier-Mott excitons in the framework of the envelope function approximation. The optical polar vibrational modes of the nanocrystallites (vibrons) and their interaction with the electronic system are analized with the help of a continuum model satisfying both the mechanical and electrostatic matching conditions at the interface. An explicit expression for the hyper-Raman scattering efficiency is derived, which is valid for incident two-photon energy close to the exciton resonances. The dipole selection rules for optical transitions and Fr\"ohlich-like exciton-lattice interaction are derived: It is shown that only exciton states with total angular momentum $L=0,1$ and vibrational modes with angular momentum $l_p=1$ contribute to the hyper-Raman scattering process. The associated exciton energies, wavefunctions, and vibron frequencies have been obtained for spherical CdSe zincblende-type nanocrystals, and the corresponding hyper-Raman scattering spectrum and resonance profile are calculated. Their dependence on the dot radius and the influence of the size distribution on them are also discussed.Comment: 12 pages REVTeX (two columns), 2 tables, 8 figure

Identifying discrete behavioural types: A re-analysis of public goods game contributions by hierarchical clustering

We propose a framework for identifying discrete behavioural types in experimental data. We re-analyse data from six previous studies of public goods voluntary contributions games. Using hierarchical clustering analysis, we construct a typology of behaviour based on a simi- larity measure between strategies. We identify four types with distinct sterotypical behaviours, which together account for about 90% of participants. Compared to previous approaches, our method produces a classification in which different types are more clearly distinguished in terms of strategic behaviour and the resulting economic implications

Clonidine as an adjuvant to local anesthetic in supraclavicular brachial plexus block: a randomized, double blinded placebo controlled study

Background: Many drugs have been studied as adjuvants to local anesthetic agents with the aim of improving the quality of anesthesia and to provide profound analgesia. Clonidine has also been used as an adjunct to local anesthetic agents in various regional techniques. The studies regarding clonidine in brachial plexus block have given mixed results. Aim was to determine whether addition of clonidine to the local anesthetic solution for brachial plexus block by supraclavicular approach, prolongs sensory and motor blockade and improves postoperative analgesia. Also to observe side effects if any.Methods: 60 patients aged 18-60 years, were randomly allocated into two groups. Group A received 2 µg / kg of Clonidine diluted to 1 ml with saline and group B received 1 ml of saline added to bupivacaine (10 ml 0.5%) and lignocaine (20 ml 2 %) solution, in the supraclavicular block. The onset and duration of sensory and motor block was compared along with the duration of analgesia, sedation in both the groups. Patients’ pulse rate, blood pressure, saturation was also recorded.Results: Addition of clonidine had no effect on the onset of the block, but was found to increase the duration of sensory and motor block along with the increase in the duration of analgesia. Visual analogue score for pain was significantly lower in the group receiving clonidine.Conclusions: Clonidine 2 µg / kg added to 10 ml of 0.5 % Bupivacaine + 20 ml of 2% lignocaine with adrenaline (1:200000) is a good option for improving the quality and duration of supraclavicular brachial plexus block