Luminescence Dynamics of BaAl2O4:Eu2+ Phosphor.

We studied steady-state and time-resolved photoluminescence of Eu doped BaAl2O4 phosphor. The undoped BaAl2O4 sample shows a dominant blue emission band at ~ 428 nm and two secondary maxima at ~ 405 and 456 nm due to F-centre and aggregate defects such as F2 -centre. The samples after doping of Eu at 1-5% show additional emission bands at ~ 485 and 518 nm due to Eu2+ centre and a red emission band at ~ 657 nm is attributed to Eu3+ centre. The sample doped with 2% of Eu shows anomalous emission having the dominant peak at ~ 494 nm. The average luminescence lifetime of the emission band at ~ 428 nm in the undoped sample was estimated to be (3.29 ± 0.91) ns. The average luminescence lifetime of this emission band after doping of Eu was found to increase by 102 orders of magnitude. The intensity of the 428 nm blue emission band was found to quench after doping of Eu beyond 3%. The concentration quenching effect was attributed to dipole-quadrupole interaction. Further, a non-radiative fluorescence energy transfer mechanism from an extrinsic Eu2+ centre to an intrinsic F-centre is proposed to describe the luminescence dynamics of the samples.

Study of Concentration Quenching and Energy Transfer Mechanism in Ce Doped Y2O3 Nanomaterials.

We study concentration quenching and energy transfer mechanisms of yttrium oxide (Y2O3) nanomaterials doped with different concentrations (0-5 mol%) of cerium (Ce). Photoluminescence (PL) spectra recorded under an excitation wavelength of 350 nm show a broad emission band at ∼ 406 nm and a feeble emission band at ∼ 463 nm in the undoped Y2O3 sample. The doping of Ce in Y2O3 induced multiple PL peaks within the blue-green region of the spectrum in all the doped samples with the peak at ∼ 466 nm being notably the prominent one. This prominent emission band exhibits a decrease in intensity with increasing Ce concentration due to concentration quenching. Analysis of Time-resolved photoluminescence (TRPL) spectra reveal that the average emission lifetime of Ce-doped Y2O3 is shorter than that of the undoped Y2O3 sample. The concentration quenching effect and the decrease of average emission lifetime of the dominant emission band are explained on the basis of energy transfer from the host Y2O3 to the Ce3+ ion centres. The critical quenching concentration of Ce3+ ion in Y2O3:Ce phosphor was identified to be 1 mol% and the critical transfer distance was estimated to be 23.74 Å. Analysis reveal that the concentration quenching mechanism involves nearest-neighbour interaction.

Optical properties of blue-light-emitting Y2 O3 :Ce nanophosphor for solid-state lighting application.

The structural, surface morphological, optical absorption and emission features of Y2 O3 :Ce (0%-5%) were studied. The samples had a body-centred cubic crystal structure. The undoped sample had a crystallite size of 29.03 nm, and it varied after doping with Ce. The grain size of the samples varied from 23.00 to 50.78 nm. All the samples exhibited a strong absorption band at 206 nm due to F-centre absorption and absorption involving the delocalised bands. In addition, the doped samples exhibited a secondary band at ~250 nm due to 4f → 5d transitions of Ce3+ ions. The optical bandgap of the undoped sample was found to be ~5.37 eV, and it decreased to 5.20 eV with an increase in Ce concentration to 5%. The undoped sample under 350-nm excitation exhibited a broad photoluminescence (PL) emission band with the maxima at 406 nm and a secondary band at 463 nm. In contrast, multiple PL peaks were centred at ~397, 436, 466, 488 and 563 nm in all the doped samples. The average lifetime of the emission band at 406 nm was 1.05 ns and that of the emission band at ~466 nm was 1.63 ns. The material has potential for solid-state lighting applications.

Impaired Autophagy Flux is Associated with Proinflammatory Microglia Activation Following Japanese Encephalitis Virus Infection.

Role of autophagy in Japanese encephalitis viral (JEV) infection is not well known. In the present study, we reported the role of autophagy flux in microglia activation, neurobehavioral function and neuronal death using a mouse model of JEV. Markers for autophagy (LC3-II/I, SQSTM1/P62, phos-Akt, phos-AMPK), and neuronal death (cleaved caspase 12, H2Ax, polyubiquitin) were investigated by western blot at 1, 3 and 7 days post inoculation. Cathepsin D was measured in cerebral cotex of JEV infected mice spectrophotometrically. Microglia activation and pro-inflammatory cytokines (IL1ß, TNF-α, IFNγ, IL6) were measured by immunohistochemistry, western blot and qPCR analysis. In order to determine the neuroinflammatory changes and autophagy mediated neuronal cell death, BV2-microglia and N2a-neuronal cells were used. Autophagy activation marker LC3-II/I and its substrate SQSTM1/P62 were significantly increased while cathepsin D activity was decreased on day 7 post inoculation in cerebral cortex. Microglia in cortex were activated and showed higher expression of proinflammatory mRNA of IL1ß, TNF-α, IFNγ and IL6, with increased DNA damage (H2AX) and neuronal cell death pathways in hippocampus and neurobehavioral dysfunction. Similar observations on JEV infection mediated autophagy flux inhibition and neuronal cell death was found in N2a neuronal cell. Collectively, our study provides evidence on the role of autophagy regulation, microglial activation and neurodegeneration following JEV infection.

Possible role of transforming growth factor ß in tuberculous meningitis.

BACKGROUND: Transforming growth factor ß (TGF-ß) is an anti-inflammatory cytokine and its role in hydrocephalus and stoke has been suggested. Tuberculous meningitis (TBM) is associated with exudates, stroke, hydrocephalus and tuberculoma, but the role of TGF-ß has not been evaluated in relation to these changes. AIM: To evaluate the cerebrospinal fluid (CSF) TGF-ß level in the patients with TBM, and correlate these with clinical findings, MRI changes, paradoxical response and outcome at 6months. METHODS: TBM patients diagnosed on the basis of clinical, CSF and MRI criteria were prospectively included. The clinical details including duration of illness, seizures, focal motor deficit, Glasgow Coma Scale (GCS) score and stage of TBM were noted. Presence of exudate, hydrocephalus, tuberculoma and infarction in MRI was also noted. MRI was repeated at 3months and presence of paradoxical response was noted. Cerebrospinal fluid TGF-ß was measured using ELISA on admission and repeated at 3months and these were compared with 20 controls. RESULTS: TGF-ß level was significantly higher in TBM compared to the controls (385.76±249.98Vs 177.85±29.03pg/ml, P<0.0001). TGF-ß correlated with motor deficit, infarction and tuberculoma on admission but did not correlate with CSF abnormalities, drug induced hepatitis, paradoxical response and outcome. TGF-ß level at 3months was significantly lower than the baseline but remained higher than the controls. CONCLUSION: CSF TGF-ß levels are elevated in TBM and correlate with infarction and tuberculoma.

Spectrum of hyperosmolar hyperglycaemic state in neurology practice.

BACKGROUND & OBJECTIVES: Hyperosmolar hyperglycaemic state (HHS) is a medical emergency, but there is a paucity of studies reporting the spectrum of neurological manifestations of HHS. We, therefore, report the neurological spectrum, triggering factors and outcome of HHS in general neurology practice. METHODS: The records of the patients with HHS were extracted from computerized hospital information system and those managed currently were prospectively included. The demographic, clinical manifestations, duration of diabetes and precipitating events such as infection, stress and stroke were noted. Patients with HHS were categorized into seizure, movement disorder and encephalopathy groups. Their electroencephalography, magnetic resonance imaging (MRI) findings and outcome were noted. RESULTS: There were 17 patients with HHS (age range 40 and 75 yr) and seven were females. Seven patients were diabetic for five years, one for four years, one for one year and four were diagnosed after the occurrence of HHS. Four patients had epilepsia partialis continua persisting for 72-360 h, one patient had focal seizures and his MRI revealed T2 hyperintensity in frontal region in one patient and cerebellar vermian hyperintensity in another. All the five patients improved, but two had neurological deficits on discharge. Nine patients had encephalopathy which was precipitated by stroke in six patients, urinary infections in two and meningitis in one. Three females had hemichorea-hemiballismus syndrome, which was triggered by infections. Abnormal movements lasted 5-10 days and responded to correction of hyperosmolarity. Nine out of 17 patients improved completely whereas the remaining eight had partial recovery, these patients had stroke, ventilator-related complications or meningoencephalitis. INTERPRETATION & CONCLUSIONS: The most common presentation of HHS was encephalopathy (9) followed by seizure (5) and hemichorea-hemiballismus syndrome (3) which responded to the correction of hyperosmolar state.

Is VEGF a marker of severity of scrub typhus infection?

Vascular endothelial growth factor (VEGF) and its receptors have been reported as severity markers of septicemia. Scrub typhus (ST) results in multi-organ dysfunction but the role of VEGF has not been evaluated. We report VEGF and its receptors in ST and its correlation with severity, outcome and laboratory findings. Thirty patients with ST diagnosed by solid phase immune chromatographic assay and Weil-Felix tests were included. Their clinical details, Glasgow Coma Scale (GCS), SOFA and modified Rankin Scale (mRS) scores and laboratory findings were noted. VEGF, VEGFR1 and VEGFR2 were done by ELISA at admission and repeated at 1 month. Outcome was defined at 1 month. Serum VEGF and VEGF-R1 levels were significantly higher and VEGFR2 was significantly lower in the ST patients compared to the controls. These levels significantly improved at 1 month. VEGF level correlated with SOFA score (p = 0.05) and SGPT (p = 0.04). VEGFR1 correlated with hemoglobin (p = 0.04), platelet count (p = 0.03), serum CK (p = 0.001), weakness (p = 0.04) and mRS score (p = 0.04). VEGFR2 did not correlate with any clinical or laboratory parameters. All the patients recovered with doxycycline. Serum VEGF and VEGFR1 levels increased in ST and suggest disease severity but do not predict outcome.

Quality of anticoagulation therapy in neurological patients in a tertiary care hospital in north India.

BACKGROUND & OBJECTIVES: There is paucity of studies on the quality of anticoagulation in neurological patients from India. This study evaluates the quality of oral anticoagulation therapy in neurology patients. METHODS: Consecutive patients attending a tertiary care neurology service in north India who were prescribed oral anticoagulant (OAC), were included. Their international normalized ratio (INR) values were prospectively monitored and the earlier INR values of the patients who were already on OAC were retrospectively analyzed. The patients with multi-organ dysfunction, pregnancy and those below 18 yr of age were excluded. The therapeutic INR range was defined as per standard recommendations. The level of anticoagulation, factors interfering with OAC and complications were noted. RESULTS: The results were based on 77 patients with median age 40 yr. Fifty one patients received OAC for secondary stroke prevention, 23 for cerebral venous sinus thrombosis (CVST) and three for deep vein thrombosis (DVT). A total 167.9 person-years of follow up was done with a median of 1.2 (0.3-9.3) years. of the 1287 INR reports, 505 (39.3%) reports were in the therapeutic range, 496 (38.5%) were below and 282 (21.91%) were above the therapeutic level. Stable INR was obtained in 33 (42.86%) patients only. INR level was improved by dose adjustment in 20 (26%), drug modification in two (2.6%), and dietary adjustment in six (7.8%) patients. Three patients were sensitive and five were resistant to OAC. Complications were noted in 28 instances; thromboembolic in 16 and haemorrhagic stroke in 12. The overall complication rate was 16.7 per 100 person-years. INTERPRETATION & CONCLUSIONS: It may be concluded that stable therapeutic INR is difficult to maintain in neurological patients. Optimal modification of diet, drug and dose of oral anticoagulant may help in stabilization of INR.

VEGF and its receptors in dengue virus infection.

Vascular permeability determines the severity of dengue virus infection. Vascular endothelial growth factor (VEGF) and its (receptor 1) R1 and (receptor 2) R2 receptors may provide insight about the neurological complications of dengue. We report VEGF and its R1 and R2 receptors level in dengue patients and correlate these with neurological complications. Consecutive patients with dengue were subjected to clinical and neurological evaluations. Their blood counts, serum chemistry, including liver and kidney function tests, serum creatine kinase (CK), and albumin were measured. VEGF, VEGFR1 and VEGFR2 were measured by ELISA in the patients and 16 matched controls. Twenty four patients with dengue were included whose ages ranged between 15 and 67 years, and nine of whom were females. Serum VEGF level was insignificantly lower in dengue patients whereas VEGFR1 was significantly higher (P = 0.01) and VEGFR2 was significantly lower (P = 0.005) compared to controls. VEGFR2 correlated with systolic blood pressure, coagulopathy, and serum CK levels. None of the other clinical and biochemical parameters correlated with VEGF and VEGFR1 levels. VEGFR1 and R2 normalized at 1 month. VEGFR2 correlates with the clinical severity of dengue and muscle dysfunction.

Neurological manifestations of scrub typhus.

OBJECTIVE: To evaluate the neurological manifestations of scrub typhus and correlate their clinical, EEG and MRI findings. METHODS: A cross-sectional study over 2 years included patients with scrub typhus diagnosed by solid phase immunochromatographic assay or Weil-Felix test. A detailed clinical evaluation including Glasgow Coma Scale (GCS) was documented. Blood counts, chemistry, ECG, chest radiograph, cerebrospinal fluid (CSF), EEG and cranial MRI were performed. Outcome on discharge and at 1 month were categorised into good and poor based on modified Rankin Scale. RESULTS: Thirty-seven patients with ages ranging between 3 and 71 years were included; 51% of whom were females. All patients had fever and myalgia. Thirty-one (84%) patients had impaired consciousness, and six were deeply comatose (GCS score ≤8). Eight patients presented with status epilepticus. MRI revealed meningeal enhancement in only 1/25 (4%) patient and EEG showed generalised slowing in 6/28 (21.4%). Among 31 patients with altered sensorium, CSF studies were conducted on 28. Nineteen patients had meningoencephalitis and 9 encephalopathy, but no significant differences were observed in clinical, laboratory, EEG and MRI findings. All patients responded within 48 h to doxycycline and had good recovery at 1 month. Patients with low GCS score had significantly more focal neurological deficit (r=0.5; p=0.002), longer hospital stay (r=-0.4; p=0.03) and more disability on discharge (r=-0.4; p=0.01). CONCLUSIONS: Meningoencephalitis/encephalopathy may be seen in two-third of patients with scrub typhus. Scrub typhus should be included in the differential diagnosis of febrile encephalopathy.

Safety and efficacy of levofloxacin versus rifampicin in tuberculous meningitis: an open-label randomized controlled trial.

OBJECTIVES: We report the efficacy and safety of levofloxacin versus rifampicin in tuberculous meningitis (TBM). PATIENTS AND METHODS: In this open-label, randomized controlled trial from India, patients with TBM diagnosed on the basis of clinical, MRI and CSF findings were included. Patients with hepatic or renal dysfunction, organ transplantation, malignancy, pregnancy, lactation, allergy, seizure, age <15 years and antitubercular treatment ≥1 month were excluded. Sixty patients each were randomized to levofloxacin (10 mg/kg, maximum 500 mg) or rifampicin (10 mg/kg, maximum 450 mg). They also received isoniazid, pyrazinamide, ethambutol, prednisolone and aspirin. The primary outcome was death and secondary outcome measures were 6 month disability, repeat MRI changes and serious adverse events (SAEs). RESULTS: The median age of the patients was 34.5 (16-75) years. The baseline clinical and MRI findings were similar between the two groups. At 6 months, 13 out of 60 (21.7%) patients in the levofloxacin arm and 23 out of 60 (38.3%) patients in the rifampicin arm had died (P = 0.07). On Cox regression analysis, survival in the levofloxacin group was significantly better than in the rifampicin group (hazard ratio 2.13, 95% CI 1.04-4.34, P = 0.04). The functional outcome (P = 0.47) was, however, not significantly different between the two groups. On intention-to-treat analysis, 10 out of 47 (21.3%) in the levofloxacin arm and 5 out of 37 (13.5%) in the rifampicin arm had poor recovery. Repeat MRI findings did not differ between the groups. Levofloxacin was discontinued more frequently than rifampicin due to SAEs (16 versus 4, P = 0.01). CONCLUSIONS: Levofloxacin is superior to rifampicin in reducing 6 month death in TBM but not disability. Levofloxacin may be used in TBM especially in those patients with hepatotoxicity and without seizure.

Predictors of outcome of myasthenic crisis.

There is paucity of study on predictors of myasthenic crisis (MC), prolonged ventilation and their outcome, a reason why this study was undertaken. Sixty-four patients with myasthenia gravis (MG) were included whose median age was 45 (6-84) years. Their clinical treatment, presence of thymoma, anti-acetylcholine receptor antibody (AchRAb), thymectomy, comorbidities, offending drugs and occurrence of MC were noted. Patients needing prolonged ventilation (>15 days) were noted. Hospital mortality, MG quality of life (QOL) at discharge and thereafter annual hospital visit, admission, expenditure and work day loss were enquired. Fourteen (21.9 %) patients had MC within 1-120 (median 8.5) months of disease onset within a median follow-up of 48 (3-264) months. The precipitating factors were infection in six, surgery in five, tapering of drugs in two and reaction to iodinated contrast in one patient. Male gender, bulbar weakness, AchRAb, thymoma, surgery and comorbid illnesses were related to MC. Eight of them (57.1 %) needed prolonged ventilation. Half the patients with MC had recurrent crisis (2-4 attacks). Death was not related to MC although MC patients had worse QOL, higher annual treatment expenditure with frequent hospital visit and hospitalization. In conclusion, association of comorbid illness with MC and prolonged ventilation highlights the need of close follow-up and appropriate management.

Sensitivity of ZnO Film-Based X-ray Sensors: A Comprehensive Study on the Effect of Thickness of ZnO Layer.

For all types of photosensors, efficient absorption of photons of particular interest is very essential. We report the effect of thickness of the ZnO layer in ZnO film-based X-ray sensors. A set of five samples Z1, Z2, Z3, Z4, and Z5 is developed by varying the thickness of the ZnO layer between 10 and 73 µm. The dark I-V characteristics of the sensors show a "pseudorectifying" type nature. A quantitative analysis of the dark currents reveals that the dark I-V characteristics are affected by space charge limited current (SCLC) due to intrinsic defects present in the ZnO films. The effect of the SCLC is prominent in the thicker films in comparison to the thinner ones. The sensors show high signal-to-noise (S/N) ratio below 5.0 V bias voltage. The S/N ratio is found to increase with the thickness of the ZnO layer due to efficient absorption of X-ray photons. The photoresponse characteristics of the sensors against dose rate are sublinear between 0.015 and 0.234 Gy/s. The photoresponse time of the sensors are found to be nearly 1 s. The sensitivities of Z1, Z2, Z3, Z4, and Z5 sensors at 4.5 V bias voltage for 0.234 Gy/s dose rate are estimated to be 55.51, 337.08, 312.01, 152.81, and 103.52 µC/Gy cm3, respectively. The sensitivity of the device is found to increase with increase in thickness of the ZnO layer and reaches an optimum level for the thickness of about 19-26 µm. Beyond this range, the sensitivity is found to decrease due to the Schubweg effect.

Stimulus-sensitive myoclonus and cerebellar ataxia following chikungunya meningoencephalitis.

Chikungunya virus was initially thought to be a non-neurotropic virus, but recently neurological complications have been reported in patients with chikungunya virus infection. Here, we report a rare case of stimulus-sensitive myoclonus following chikungunya meningoencephalitis. The cranial MRI scan of the patient was normal, the cerebrospinal fluid contained 200 lymphocytes/mm(3), and the serum immunoglobulin M ELISA was positive for chikungunya. The patient improved completely after 1 month of treatment. This case study illustrates that chikungunya virus should also be considered in a febrile patient with myoclonus, especially in an endemic area.

Amitriptyline vs divalproate in migraine prophylaxis: a randomized controlled trial.

OBJECTIVE: This study compares efficacy and safety of divalproate extended release (DVA-ER) and amitriptyline (AMT) in migraine. MATERIALS AND METHODS: Three hundred migraineurs having >4 attacks monthly were randomized into DVA-ER or AMT. The primary end points were >50% reduction in frequency, ≥1 grade improvement in the severity, and >50% improvement in a visual analogue scale (VAS). Secondary end points were functional disability, rescue medication, and adverse events. RESULTS: The median age was 32 years, and 241 were women. 150 patients each received DVA-ER and AMT. At 3 months, 74.7% in DVA-ER and 62% patients in AMT group improved in headache frequency (P = 0.02) and at 6 months, 65.3% and 54%, respectively (P = 0.90). At 3 months, the VAS score improved by >50% in 80.7% in DVA-ER and 64% in AMT (P = 0.005). At 6 months, there was no significant difference between the two groups in VAS score (69.3% vs 56%; P = 0.47) and other outcome parameters. The composite side effects were also not different between the two groups (68% vs 81%); however, hair fall, menstrual irregularity, polycystic ovary, and weight gain were commoner in DVA-ER group. CONCLUSION: Divalproate extended release is more effective at 3 months than AMT; however, at 6 months, both are equally effective in migraine prophylaxis.

Low molecular weight heparin versus unfractionated heparin in cerebral venous sinus thrombosis: a randomized controlled trial.

BACKGROUND: There is no randomized controlled trial (RCT) evaluating the efficacy and safety of low molecular weight heparin (LMWH) compared to unfractionated heparin (UFH) in cerebral venous sinus thrombosis (CVST). In this RCT, we have evaluated the efficacy and safety of LMWH versus UFH in CVST. METHODS: Consecutive patients with CVST diagnosed on the basis of MR venography (MRV) who was free of bleeding diathesis, malignancy, hepatic or renal failure were prospectively enrolled. History, clinical findings and risk factors were evaluated. MRI and MRV findings were recorded. The patients were randomized to LMWH and UFH groups for 14 days followed by oral anticoagulant. The hospital mortality and 3 months outcome as assessed by Barthel index (BI) score were noted. RESULTS: 32 patients received UFH and 34 received LMWH. The baseline demographic, clinical and radiological parameters were similar in both the groups. Six patients died and all were in UFH group (P = 0.01). At 3 months, insignificantly higher number of patients recovered completely in LMWH compared to UFH group (30 vs. 20). There was no serious side effect needing withdrawal of drugs except one was withdrawn from UFH because of heparin-induced thrombosis. CONCLUSION: Low molecular weight heparin resulted in significantly lower hospital mortality in CVST compared to UFH.

Dengue-associated transient muscle dysfunction: clinical, electromyography and histopathological changes.

BACKGROUND: Dengue is commonly associated with myalgia, but there is paucity of studies on the frequency, severity, and basis of muscle involvement. The aim of this study was to document the clinical, electromyographic, and histological changes in dengue-associated muscle dysfunction. MATERIALS AND METHODS: Seropositive dengue patients admitted to the neurology ward during 2010 were enrolled in this study. Detailed medical history, including bleeding diathesis and organomegaly, were noted. Muscle power on a 0-5 scale, muscle tone, reflex, sensations and coordination were tested. Blood counts, hemoglobin, and serum chemistry, including creatine kinase (CK) evaluations, were carried out. Concentric needle electromyography (EMG) and muscle biopsy were performed when clinical conditions were suitable. RESULTS: The study cohort comprised 39 patients with dengue, with a median age of 28 years. Of these, 31 patients showed evidence of muscle involvement-16 with clinical and 15 with subclinical muscle involvement. Eight of these patients had severe weakness and five had hyporeflexia. Thrombocytopenia was present in 26 patients, elevated serum creatinine in three patients and liver dysfunction in 31 patients. The median CK level was 837 (range 194-3,832) U/L. The EMG revealed polyphasic normal to short duration motor unit potentials, but spontaneous activity was absent. Muscle biopsy in three patients revealed interstitial hemorrhage with occasional necrosis and myophagocytosis. There was no vasculitis, but subtle inflammatory changes were present in one patient. The severity of muscle weakness correlated with the platelet count and CK level. All patients improved by 15 days of treatment initiation. CONCLUSION: Dengue commonly results in benign and self-limiting transient muscle dysfunction.

Phototransferred thermoluminescence characteristics of microcline (KAlSi3O8) under 470 nm blue- and 870 nm infrared-light illumination.

We report phototransferred thermoluminescence (PTTL) induced in microcline by 470 nm blue- and 870 nm infrared-light. A conventional thermoluminescence (TL) glow curve measured from a sample irradiated to 40 Gy produces five composite TL glow peaks P1, P2, P3, P4 and P5 at 90, 123, 166, 298 and 391 °C respectively. The sample produces PTTL peaks also identified as P1, P2, P3 and P4 following illumination by blue or infrared light after irradiation to 40 Gy and preheating to 400 °C. Step-annealing suggests the presence of deep electron traps associated with a signal beyond 500 °C. However, preheating to 500 °C and exposure to blue or infrared light does not produce significant PTTL peaks. For doses between 40 Gy and 100 Gy, the maximum PTTL is emitted within 60 and 150 s of blue light illumination. On the other hand, the same feature under the infrared light illumination occurs within 100-200 s of illumination. PTTL peaks P1, P2, P3 and P4 reproduced under blue light illumination have a linear dose response between 10 Gy and 100 Gy and those reproduced under infrared light illumination have a superlinear dose response between 10 and 100 Gy. In contrast, donor peak P5 in both cases follows sublinear dose response within the same dose range. Fading of PTTL peaks P1, P2, P3 and P4 as well as the donor peak P5 are negligibly small under blue light illumination compared to that of infrared light illumination. PTTL glow curves are also found to be properly reproducible.

Status epilepticus: why, what, and how.

Status epilepticus (SE) is an important neurological emergency with high mortality and morbidity. The first official definition of SE was the product of 10 th Marseilles colloquium held in 1962 which was accepted by International League Against Epilepsy in 1964. There are as many types of SE as of seizures. SE is supposed to result from failure of normal mechanisms that terminate an isolated seizure. In half of the cases, there is no history of epilepsy and SE is precipitated by some intercurrent infection. In children, it is often infection, whereas in adults, the major causes are stroke, hypoxia, metabolic derangements, and alcohol intoxication or drug withdrawal. The treatment of SE aims at termination of SE, prevention of seizure recurrence, management of precipitating causes, and the management of complications. The extent of investigations done should be based on the clinical picture and cost benefit analysis. The first line antiepileptic drugs (AED) for SE include benzodiazepines, phenytoin, phosphenytoin, and sodium valproate. Mortality of SE ranges between 7 and 39% and depends on underlying cause and response to AEDs.