Vertebral arteries bilaterally passing through stellate (cervicothoracic) ganglion

Vertebral artery is a branch of the first part of subclavian artery. Vertebral artery arising from the aortic arch most commonly presents on the left side. The cervical part of sympathetic trunk is closely related to the vertebral artery in the cervical region. Though lots of variations regarding anomalous origin, course of vertebral artery is reported in the literature, here we present a rare anomaly in which vertebral artery after originating from aortic arch is passing through stellate ganglia and it enters into the transverse foramina of higher cervical vertebra (C5). Such variation should be kept in mind by anaesthetist during stellate ganglion block in order to relieve intractable pain in central nervous system lesion. Surgeons should keep this anomaly in mind during cervical spine surgery otherwise vertebral artery may get injured leading to haemorrhage

Chemoselective C-benzoylation of phenols by using AlCl3 under solvent-free conditions

Substituted phenols were chemo-selectively reacted with benzoylchloride in presence of aluminum chloride under solvent-free condition to afford the corresponding 2'-hydroxy aryl benzophenones in excellent yields (72-96%). Naphthol benzoylation resulted in lower yields as compared to phenols. Both reactions completed in 5-10 min with quantitative yields providing excellent control over regioselectivity of products. KEY WORDS: Chemoselective C-acylation, F-C reaction, Fries rearrangement Bull. Chem. Soc. Ethiop. 2015, 29(2), 319-325DOI: http://dx.doi.org/10.4314/bcse.v29i2.1

A convenient method for lactonization of α-allyl esters using iodine in dimethyl- sulphoxide

A simple method for the synthesis of α-γ-disubstituted-γ-butyrolactones by cyclization of α-allyl esters using iodine in dimethylsulphoxide is reported. This method is efficient and operationally simple in comparison to methods using transition metal complexes. KEY WORDS: γ-Butyrolactones, α-Allyl esters, Iodine, Dimethyl sulphoxide Bull. Chem. Soc. Ethiop. 2014, 28(3), 469-473.DOI: http://dx.doi.org/10.4314/bcse.v28i3.1

A Novel Method for Graphical Password Mechanism

For the verification of authorized users in computer systems, various text based or biometrics methods are used. But these methods have some drawbacks. It is difficult to remember and recall the textual i.e. alphanumeric passwords. To avoid this drawback users prefer to create effortless, short, easy and insecure passwords which are easily guessable by hacker and this makes the system more vulnerable to attacks. On other hand, verification mechanisms based on biometrics offers security to a good extents. But they are quite luxurious for implementation. Cost becomes a key factor in the case of biometrics. Also any injury to the body part used in biometric authorization results in denial of access or performance issues. Graphical password provides another way by providing passwords that are more protected and unforgettable in a reasonable price. In this system, user clicks on images instead of typing passwords for accessing the system. This paper describes and examines usability and security of graphical password mechanism for authentication using graphical passwords. Proposed system describes characteristics for security and performed empirical study comparing Graphical password mechanism with Biometric passwords and alphanumeric password. DOI: 10.17762/ijritcc2321-8169.15013

A consistent and robust measurement of the thermal state of the IGM at 2 ≤ z ≤ 4 from a large sample of Ly α forest spectra: Evidence for late and rapid He ii reionization

We characterise the thermal state of the intergalactic medium (IGM) in ten redshift bins in the redshift range $2 \leq z \leq 4$ with a sample of 103 high resolution, high S/N Ly$\alpha$ forest spectra using four different flux distribution statistics. Our measurements are calibrated with mock spectra from a large suite of hydrodynamical simulations post-processed with our thermal IGM evolution code CITE, finely sampling amplitude and slope of the expected temperature-density relation. The thermal parameters inferred from our measurements of the flux power spectrum, Doppler parameter distribution, as well as wavelet and curvature statistics agree well within their respective errors and all clearly show the peak in temperature and minimum in slope of the temperature density relation expected from HeII reionization. Combining our measurements from the different flux statistics gives $T_0=(14750 \pm 1322)$K for the peak temperature at mean density and a corresponding minimum slope $\gamma = 1.225 \pm 0.120$. The peak in the temperature evolution occurs at $z \approx 3$, in agreement with previous measurements that had suggested the presence of such a peak, albeit with a large scatter. Using CITE, we also calculate the thermal state of the IGM predicted by five widely used (spatially homogeneous) UV-background models. The rather rapid thermal evolution inferred by our measurements is well reproduced by two of the models, if we assume (physically well motivated) non-equilibrium evolution with photo-heating rates that are reduced by a moderate factor of $\sim 0.7-0.8$. The other three models predict HeII reionization to be more extended with a somewhat earlier as well as higher temperature peak than our measurements suggest