Artery of percheron infarct: a case report

Artery of Percheron is a part of the posterior circulation occlusion of which is relatively uncommon. It is classically characterised by bilateral infarcts in areas involving the rostral midbrain and/or ventromedial thalamus best seen by a diffusion-weighted imaging (DWI) sequence using MRI. Clinical presentations are variable and include, amnesic impairment, aphasia, dysarthria, ocular movement disorders, motor deficit and cerebellar signs. Our case was a 60-year-old hypertensive and diabetic male with history of alcohol abuse who presented with sudden derangement of sensorium along with restriction of ocular movements and marked cerebellar signs. The diagnosis of werniche encephalopathy suggested initially by the radiologist was rejected because of the acute onset, history of hypertension and marked cerebellar signs which suggested a cerebrovascular accident. Bilateral infarcts with the occlusion of a single artery i.e. artery of percheron which supplies structures bilaterally can easily be confused with werniche encephalopathy which has similar clinical and radiological picture but are managed on different lines. This diagnosis should be kept in mind in drowsy patients with restricted ocular movements and bilateral thalamic and midbrain hyperintensities

Coping with Illness: Insight from the Bhagavad Gita

The Shrimad Bhagavad Gita enlightens everyone on how to cope up with various situations in life. It uses the conversation between Lord Krishna and Arjuna to highlight initial negative coping mechanisms exhibited by the latter. It goes on to showcase positive coping skills suggested by Lord Krishna and implemented by Arjuna. The Bhagavad Gita, through this case-based methodology, teaches us how to cope with a demanding situation. Diabetes is a lifestyle disease, which warrants a thorough change in one\u27s lifestyle, including changes in basic activities such as diet and exercise. This brief communication utilizes the teachings of Bhagavad Gita to help in coping with illness, especially chronic illness such as diabetes. The article cites verses from the Bhagavad Gita to show how one may cope with the stress of illness such as diabetes

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Multi-messenger Observations of a Binary Neutron Star Merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∼ 1.7 {{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of {40}-8+8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 {M}ȯ . An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∼ 40 {{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∼ 9 and ∼ 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.</p

Electron acceleration by a radially polarized laser pulse during ionization of low density gases

The acceleration of electrons by a radially polarized intense laser pulse has been studied. The axial electric field of the laser is responsible for electron acceleration. The axial electric field increases with decreasing laser spot size; however, the laser pulse gets defocused sooner for smaller values and the electrons do not experience high electric field for long, reducing the energy they can reach. The electron remains confined in the electric field of the laser for longer and the electron energy peaks for the normalized laser spot size nearly equal to the normalized laser intensity parameter. Electron energy peaks for initial laser phase ϕ_{0}=π due to accelerating laser phase and decreases with transverse initial position of the electrons. The energy and angle of the emittance spectrum of the electrons generated during ionization of krypton and argon at low densities have been obtained and a right choice of laser parameters has been suggested to obtain high energy quasimonoenergetic collimated electron beams. It has been found that argon is more suitable than krypton to obtain high energy electron beams due to higher ionization potential of inner shells for the former

Reference values for the cross-sectional area of the normal sciatic nerve using high-resolution ultrasonography

AIM: High-resolution ultrasonography is a new and promising technique to evaluate peripheral and spinal nerves. Its validity as a diagnostic tool in neurological diseases has been demonstrated in adults. The aims of study were to establish the reference values for the cross-sectional area of the normal sciatic nerve on high-resolution ultrasonography, and to determine the relationship between the cross-sectional area of the normal sciatic nerve and the subjects’ age, gender, height (in cm), weight (in kg), and body mass index. MATERIAL AND METHODS: Two hundred subjects of both genders and above 18 years of age were studied with high-resolution ultrasonography. The subjects had no history of peripheral neuropathy or trauma to the lower limb. The cross-sectional areas of the normal sciatic nerves were obtained at two different levels in both lower limbs. The mean cross-sectional areas of the sciatic nerves were measured at two different levels, one located at 1 cm above the bifurcation of the sciatic nerve into the tibial and common peroneal nerves, and the other 4 cm above the bifurcation of the sciatic nerve into the tibial and common peroneal nerves. RESULTS: A positive correlation of the mean cross-sectional area was established with height, weight, and body mass index. Women had smaller cross-sectional areas of the normal sciatic nerves than men at both measuring sites. No significant relationship was established with the age of the subjects. CONCLUSIONS: The established reference values of the cross-sectional area of the sciatic nerve can facilitate the analysis of pathological nerve conditions

The effect of flap parameters on fluid rectification in a microfluidic diode

We have studied the effect of flap parameters on fluid rectification in a microfluidic diode. We use Navier–Stokes equations and arbitrary Lagrangian–Eulerian formulation to obtain dynamics of fluid flow and motion of the flap. The flap opens during forward flow and seals against a stopper during reverse flow. This allows flow in the forward direction and prevents it in the reverse direction. The rectifier is fluidic analog to a semiconductor diode in function because it rectifies fluid flow. Velocity-pressure (V-P) curves analog to the current-voltage (I-V) curves of the electronic diode has been obtained. The effect of the flap parameters, such as length, thickness, and Young’s modulus has been found out. The transient response of the flap and fluid flow under oscillating pressure driven flow has also been obtained

Reference values for the cross-sectional area of normal radial nerve at two levels using high-resolution ultrasonography

AIM OF THE STUDY: High-resolution ultrasound is less often used to evaluate the radial nerves. The radial nerve is often involved in entrapment syndromes. The aim of the study is to establish the reference values for the cross-sectional area of the normal radial nerve on high-resolution ultrasonography, and to identify relationships between the cross-sectional area and the subject’s age, gender, height, weight, body mass index, and hand dominance. MATERIAL AND METHODS: The study was conducted on 200 subjects of both sexes, between 18 and 75 years of age, who did not have history of peripheral neuropathy or trauma to the upper limb. High-resolution real-time sonographic examination of the radial nerves was performed in both arms at two different levels. Level 1 was taken just proximal to the nerve bifurcation, and level 2 just after the nerve exits the spiral grove. RESULTS: The mean cross-sectional area measured at level 2 (4.3 ± 0.4 mm(2)) was greater than that measured at level 1 (2.3 ± 0.3 mm(2)). No significant relationship was seen with age and hand dominance (p >0.05), but the cross-sectional area values at above mentioned levels were larger in males than in females (p <0.05). In addition, the cross-sectional areas of the radial nerves showed a positive correlation with height, weight, and body mass index (p <0.05). CONCLUSION: The established ultrasonographic reference values along with basic clinical data will aid in the diagnosis, response to treatment, and prognostic evaluation of peripheral neuropathies