Dissecting an Outbreak: A Clinico-epidemiological Study of Nipah Virus Infection in Kerala, India, 2018.

BACKGROUND: An outbreak of Nipah virus infection was confirmed in Kerala, India in May 2018. Five out of 23 cases including the first laboratory-confirmed case were treated at Baby Memorial Hospital (BMH), Kozhikode. The study describes the clinical characteristics and epidemiology of the Nipah virus outbreak at Kozhikode during May 2018. OBJECTIVE: To study the clinical and epidemiological profile of Nipah virus epidemic that occurred in Kerala in May 2018. METHODS: A collaborative team of physicians and epidemiologists from BMH, Medical College Hospital (MCH) Kozhikode and from the Indian Medical Association (IMA) conducted this study. The clinical and exposure history and the data on outbreak response were gathered from hospital medical records and through interviewing patient relatives and health workers using questionnaires. RESULTS: It was identified that out of the 23 patients with Nipah virus infection, 21 (91.3%) expired. Out of the 21 patients, 18 tested positive for Nipah virus by Real Time polymerase chain reaction (RT-PCR). It has been found that only the index case was infected in the community from fruit bats. Rest of the cases were due to transmission of the virus at three public hospitals. Median age was 45 years. 65% of them were males. Median incubation period was 9.5 days. Fever (100%), altered sensorium (84.2%), tachycardia (63.1%), hypertension (36.8%), segmental myoclonus (15.7%), segmental sweating (15.7%) and shortness of breath (73.6%) were common features. Mean duration of illness was 6.4 days. CONCLUSION: The rapid spread of infection uncovered the miserable state of health care system in implementing infection control measures. The case fatality and the socio-economic burden warrant developing appropriate treatments, vaccines and diagnostics.

Designing a Sum of Squared Correlations Framework for Enhancing SSVEP-Based BCIs.

This study illustrates and evaluates a novel subject-specific target detection framework, sum of squared correlations (SSCOR), for improving the performance of steady-state visual evoked potential (SSVEP) based brain-computer interfaces (BCIs). The SSCOR spatial filter learns a common SSVEP representation space through the optimization of the individual SSVEP templates. The projection onto this SSVEP response subspace improves the signal to noise ratio (SNR) of the SSVEP components embedded in the recorded electroencephalographic (EEG) data. To demonstrate the effectiveness of the proposed framework, the target detection performance of the SSCOR method is compared with the state of the art task-related component analysis (TRCA). The evaluation is conducted on a 40 target SSVEP benchmark data collected from 35 subjects. The results of the extensive comparisons of the performance metrics show that the proposed SSCOR method outperforms the TRCA method. The ensemble version of the SSCOR framework provides an offline simulated information transfer rate (ITR) of 387 ± 9 bits/min which is much higher than that of the ensemble TRCA approach (max. ITR 216 ± 27 bits/min). The significant improvement in the detection accuracy and simulated ITR demonstrates the efficacy of the proposed framework for target detection in SSVEP based BCI applications.

Latent common source extraction via a generalized canonical correlation framework for frequency recognition in SSVEP based brain-computer interfaces.

OBJECTIVE: This study introduces and evaluates a novel target identification method, latent common source extraction (LCSE), that uses subject-specific training data for the enhancement of detection of steady-state visual evoked potential (SSVEP). APPROACH: LCSE seeks to construct a common latent representation of the SSVEP signal subspace that is stable across multiple trials of electroencephalographic (EEG) data. The spatial filter thus obtained improves the signal-to-noise ratio (SNR) of the SSVEP components by removing nuisance signals that are irrelevant to the generalized signal representation learnt from the given data. In this study a comparison of SSVEP identification performance between the proposed method, extended canonical correlation analysis (ExtCCA) and multiset canonical correlation analysis (MsetCCA) was conducted using SSVEP benchmark data of 40 targets recorded from 35 subjects to validate the effectiveness of the LCSE framework. MAIN RESULTS: The results indicate that the LCSE framework significantly outperforms the other two methods in terms of both classification accuracy and information transfer rates (ITRs). SIGNIFICANCE: The significant improvement in the target identification performance demonstrates that the proposed LCSE method can be seen as a promising potential candidate for efficient SSVEP detection in brain-computer interface (BCI) systems.

Single Nucleotide Polymorphism-Based Noninvasive Prenatal Testing: Experience in India.

INTRODUCTION: Noninvasive prenatal testing (NIPT) has revolutionized prenatal screening for chromosomal aneuploidies in some countries. Its implementation has been sporadic in developing countries. Given the genetic variation of the people in different countries, we evaluated the performance of the SNP-based NIPT in India . MATERIALS AND METHODS: The Panorama™ NIPT was performed in 516 pregnancies, which had tested intermediate-to-high risk on conventional first and second trimester screening. Results were confirmed either by invasive diagnostic testing or by clinical evaluation after birth. RESULTS: Of 511 samples analyzed, results were obtained in 499 (97.7%). Of these, 480 (98.2%) were low risk and 19 were high risk. A sensitivity of 100% was obtained for detection of trisomies 21, 18, 13 and sex chromosomal abnormalities. The specificity ranged from 99.3 to 100% for abnormalities tested. Taken together, the positive predictive value for trisomies 21, 18, 13 and monosomy X was 85.7%. The average fetal fraction was 8.2%, which is lower than the average observed elsewhere. CONCLUSION: This is the first report of detailed experience with NIPT in India and demonstrates comparable performance in all aspects of testing to the results elsewhere.

Periodic component analysis as a spatial filter for SSVEP-based brain-computer interface.

BACKGROUND: Traditional spatial filters used for steady-state visual evoked potential (SSVEP) extraction such as minimum energy combination (MEC) require the estimation of the background electroencephalogram (EEG) noise components. Even though this leads to improved performance in low signal to noise ratio (SNR) conditions, it makes such algorithms slow compared to the standard detection methods like canonical correlation analysis (CCA) due to the additional computational cost. NEW METHOD: In this paper, Periodic component analysis (πCA) is presented as an alternative spatial filtering approach to extract the SSVEP component effectively without involving extensive modelling of the noise. The πCA can separate out components corresponding to a given frequency of interest from the background electroencephalogram (EEG) by capturing the temporal information and does not generalize SSVEP based on rigid templates. RESULTS: Data from ten test subjects were used to evaluate the proposed method and the results demonstrate that the periodic component analysis acts as a reliable spatial filter for SSVEP extraction. Statistical tests were performed to validate the results. COMPARISON WITH EXISTING METHODS: The experimental results show that πCA provides significant improvement in accuracy compared to standard CCA and MEC in low SNR conditions. CONCLUSIONS: The results demonstrate that πCA provides better detection accuracy compared to CCA and on par with that of MEC at a lower computational cost. Hence πCA is a reliable and efficient alternative detection algorithm for SSVEP based brain-computer interface (BCI).

Transition from Coherent to Stochastic electron heating in ultrashort relativistic laser interaction with structured targets.

Relativistic laser interaction with micro- and nano-scale surface structures enhances energy transfer to solid targets and yields matter in extreme conditions. We report on the comparative study of laser-target interaction mechanisms with wire-structures of different size, revealing a transition from a coherent particle heating to a stochastic plasma heating regime which occurs when migrating from micro-scale to nano-scale wires. Experiments and kinetic simulations show that large gaps between the wires favour the generation of high-energy electrons via laser acceleration into the channels while gaps smaller than the amplitude of electron quivering in the laser field lead to less energetic electrons and multi-keV plasma generation, in agreement with previously published experiments. Plasma filling of nano-sized gaps due to picosecond pedestal typical of ultrashort pulses strongly affects the interaction with this class of targets reducing the laser penetration depth to approximately one hundred nanometers. The two heating regimes appear potentially suitable for laser-driven ion/electron acceleration schemes and warm dense matter investigation respectively.

Expression of Podoplanin in Different Grades of Oral Squamous Cell Carcinoma.

BACKGROUND: The expression of podoplanin is up-regulated in a number of different human cancers, including squamous cell carcinoma of the oral cavity and its relationship with tumor invasion raises the possibility that podoplanin expression could be used as a biomarker for diagnosis and prognosis. AIM: The aim of the present study is to evaluate the expression of podoplanin in different grades of squamous cell carcinoma (SCC) and to correlate the expression of podoplanin with relevant clinical features such as age, sex, site and associated habits. MATERIALS AND METHODS: Retrospective study was carried on formalin fixed, paraffin embedded blocks of oral SCC (OSCC) from the archives of Department of Oral and Maxillofacial Pathology, Vishnu Dental College, Bhimavaram. Thirty diagnosed cases were included, of which 10 were well-differentiated SCC (WDSCC) (n = 10), 10 moderately DSCC and 10 poorly DSCC. Demographics including age, sex, gender and associated habit history, were recorded. Immunohistochemical staining was done with podoplanin anti D2-40 antibody, for all the cases of OSCC and assessed qualitatively. The data obtained were tabulated and subjected to statistical analysis. RESULTS: In the present study, 27 cases of SCC showed podoplanin expression and remaining three cases showed no expression. The scoring criterion suggested by Yuan et al. was followed for semi-quantitative assessment. OSCC, seven cases presented weak expression (Immunoreactive score [IRS] 0-3), 15 presented moderate expression (IRS Score 4-7) and 5 presented high expression (IRS Score > 8). The assessment of podoplanin expression in the cytoplasm, the membrane and the cytoplasm and membrane (both) of tumor cells showed overall high positivity in the cytoplasmic followed by both and the membrane. CONCLUSION: Podoplanin could be a potent biomarker in assessing the cytoplasm/membrane staining of tumor cells. Furthermore, a high level of podoplanin expression is suggestive of high frequency of lymph node metastasis and immature status in the differentiation process of OSCC.

The efficacy of transforaminal epidural steroid injections in lumbosacral radiculopathy.

BACKGROUND: Transformational epidural steroid (TFES) is commonly used to treat lumbosacral radicular pain. However, very few studies have systematically evaluated the quality of analgesia following such procedures with respect to time. OBJECTIVE: To evaluate long-term efficacy of TFES in patients with lumbosacral radiculopathy. MATERIALS AND METHODS: A prospective study including 30 patients having lumbosacral radiculopathy secondary to prolapsed disc. Outcome variables were the amount of improvement just after the procedure and thereafter at 24 hrs, 1 month, 6 month and 1 year post-procedure, respectively, using visual analog scale (VAS) and numeric rating scale (NRS). Patients also filled Roland-Morris questionnaire pre-procedure, 6 month and 1 year follow-up. All patients received Ibuprofen for 3 days following the procedure, to alleviate post- procedural pain. An option of rescue surgery was reserved in case of unbearable pain (>7 VAS), appearance of sudden motor deficit or if patient opts for surgery. Same injection was repeated if at any point of time pain had >5 in VAS. RESULTS: As per NRS, almost all patients had complete pain relief (mean 98%) immediate postprocedure. At 24 hrs, the score was 79%, at 1 month 60%, at 6 months 58.5% and at 1 year 59%. Preprocedure VAS was 9.2 and thereafter 0.6, 1.8, 3.9, 3.8 and 4.2 at similar time points. Roland-Morris score was 18/24, 10/24, 9/24, at pre-procedure, at 6 months and at 1 year, respectively. No complication was noted in any patient except post procedural local pain. CONCLUSION: Quality of pain relief produced by TFES was significant. Long-term quality of pain relief was better in patients with pain duration less than 6 months. Even though, the study was designed to inject the drug once, many of the patients required second injection. A further study with multiple injections at prefixed time interval might probably result in a better overall outcome.

Relativistic laser channeling in plasmas for fast ignition.

We report an experimental observation suggesting plasma channel formation by focusing a relativistic laser pulse into a long-scale-length preformed plasma. The channel direction coincides with the laser axis. Laser light transmittance measurement indicates laser channeling into the high-density plasma with relativistic self-focusing. A three-dimensional particle-in-cell simulation reproduces the plasma channel and reveals that the collimated hot-electron beam is generated along the laser axis in the laser channeling. These findings hold the promising possibility of fast heating a dense fuel plasma with a relativistic laser pulse.

Surface acceleration of fast electrons with relativistic self-focusing in preformed plasma.

We report an observation of surface acceleration of fast electrons in intense laser-plasma interactions. When a preformed plasma is presented in front of a solid target with a higher laser intensity, the emission direction of fast electrons is changed to the target surface direction from the laser and specular directions. This feature could be caused by the formation of a strong static magnetic field along the target surface which traps and holds fast electrons on the surface. In our experiment, the increase in the laser intensity due to relativistic self-focusing in plasma plays an important role for the formation. The strength of the magnetic field is calculated from the bent angle of the electrons, resulting in tens of percent of laser magnetic field, which agrees well with a two-dimensional particle-in-cell calculation. The strong surface current explains the high conversion efficiency on the cone-guided fast ignitor experiments.

Optimum hot electron production with low-density foams for laser fusion by fast ignition.

We propose a foam cone-in-shell target design aiming at optimum hot electron production for the fast ignition. A thin low-density foam is proposed to cover the inner tip of a gold cone inserted in a fuel shell. An intense laser is then focused on the foam to generate hot electrons for the fast ignition. Element experiments demonstrate increased laser energy coupling efficiency into hot electrons without increasing the electron temperature and beam divergence with foam coated targets in comparison with solid targets. This may enhance the laser energy deposition in the compressed fuel plasma.

Transient electrostatic fields and related energetic proton generation with a plasma fiber.

We observe a hollow structure and a fine ring in the proton images from a petawatt scale laser interaction with a "cone-fiber" target. The protons related to the hollow structure are accelerated from the cone-tip surface and deflected later by a radial electric field surrounding the fiber. Those associated with the fine ring are accelerated from the fiber surface by this radial electric field. This field is found to decay exponentially within 3 ps from about 5 x 10(12) V/m. Two-dimensional particle-in-cell simulations produce similar proton angular distributions.

Laser-pulse-induced second-harmonic and hard x-ray emission: role of plasma-wave breaking.

We report time resolved measurements of second-harmonic and hard x rays emitted during the interaction of an intense laser pulse (10(16) W cm(-2), 100 fs) with a preplasma generated on a solid target. We observe that for a particular length scale the second harmonic goes through a minimum, while hard x-ray emission on the contrary maximizes. Theoretical or numerical modeling of this anticorrelation in terms of wave breaking of strongly driven electron plasma waves clearly brings out hitherto unexplored links between the physical mechanisms of second-harmonic generation and hard x-ray emission.

Plasma devices to guide and collimate a high density of MeV electrons.

The development of ultra-intense lasers has facilitated new studies in laboratory astrophysics and high-density nuclear science, including laser fusion. Such research relies on the efficient generation of enormous numbers of high-energy charged particles. For example, laser-matter interactions at petawatt (10(15) W) power levels can create pulses of MeV electrons with current densities as large as 10(12) A cm(-2). However, the divergence of these particle beams usually reduces the current density to a few times 10(6) A cm(-2) at distances of the order of centimetres from the source. The invention of devices that can direct such intense, pulsed energetic beams will revolutionize their applications. Here we report high-conductivity devices consisting of transient plasmas that increase the energy density of MeV electrons generated in laser-matter interactions by more than one order of magnitude. A plasma fibre created on a hollow-cone target guides and collimates electrons in a manner akin to the control of light by an optical fibre and collimator. Such plasma devices hold promise for applications using high energy-density particles and should trigger growth in charged particle optics.

Nanostructures, local fields, and enhanced absorption in intense light-matter interaction.

Recent literature has reported impressive enhancements in hard-x-ray emission from short-lived solid plasmas by modulation of the interacting surface with nanostructures. We show that the modification of local electric fields near surface structures results in excessive absorption and enhanced x-ray production. A simple model based on local field variations explains the observed x-ray enhancements quantitatively.

Laser-generated ultrashort multimegagauss magnetic pulses in plasmas.

We demonstrate ultrashort (6 ps), multimegagauss (27 MG) magnetic pulses generated upon interaction of an intense laser pulse (10(16) W cm(-2), 100 fs) with a solid target. The temporal evolution of these giant fields generated near the critical layer is obtained with the highest resolution reported thus far. Particle-in-cell simulations and phenomenological modeling is used to explain the results. The first direct observations of anomalously rapid damping of plasma shielding currents produced in response to the hot electron currents penetrating the bulk plasma are presented.

Analysis of gammabeta, betagamma, gammagamma, betabeta continuous turns in proteins.

We report the observation of continuous turns in proteins which comprise individual gamma-turns or beta-turns or both that are situated immediately one after the other along the polypeptide chain. The continuous turns were identified from a representative data set of three-dimensional protein crystal structures. The gammabeta/betagamma, gammagamma and betabeta continuous turns represent peptides of varying amino acid residue lengths and conformations. The continuous turns frequently observed in proteins were: gammabeta, between a coil and a strand; betagamma, between a helix and a strand; gammagamma, between coils; and betabeta, either between a strand and a coil or between strands or coils. We determined the statistically significant amino acid residue preferences at individual positions in the turn, calculated amino acid positional potentials and analyzed main chain hydrogen bonds and side-chain interactions likely to stabilize the continuous turns. The data on continuous turns have been integrated in the database of structural motifs in proteins (DSMP) on our web server at (http://www.cdfd.org.in/dsmp.html). This is useful to make queries on sequences compatible with different continuous turns.

Analysis of gammabeta, betagamma, gammagamma, betabeta multiple turns in proteins.

The number of gamma-turns in a representative protein dataset selected from the current Protein Data Bank has increased almost seven times during the past decade. Eighty percent classic gamma-turns and 57% inverse gamma-turns are associated as multiple turns with either another y-turn or a beta-turn. We refer to these as multiple turns of the (gammabeta)1,2,3 or (betagamma)1,2,3 type, depending upon whether the gamma-turn is before or after the beta-turn along the protein chain, respectively. However, for multiple turns involving only gamma-turns, we follow the nomenclature analogous to that proposed earlier for the multiple (or double) beta-turns. Fifty-eight per cent beta-turns are associated as multiple turns with another beta-turn. We extracted multiple turns from the protein dataset and classified them on the basis of individual gamma- or beta-turn types and the number of overlapping residues. Furthermore, we evaluated the amino acid positional potentials and determined the statistically significant amino acid preferences, hydrogen bond/side-chain interaction preferences in the multiple turns and secondary structure preferences for residues immediately flanking these turns. The results of our analysis would be useful in the modeling, prediction or design of multiple turns in proteins. The amino acid sequence corresponding to the multiple turn, position in the protein chain, PDB Code/chain in which multiple turn is present and the individual turn types constituting the multiple turns are available from our website and this information would also be integrated in our Database of Structural Motifs in Proteins (http://www.cdfd.org.in/dsmp.html).

Database of structural motifs in proteins.

SUMMARY: The database of structural motifs in proteins (DSMP) contains data relevant to helices, beta-turns, gamma-turns, beta-hairpins, psi-loops, beta-alpha-beta motifs, beta-sheets, beta-strands and disulphide bridges extracted from all proteins in the Protein Data Bank primarily using the PROMOTIF program and implemented as a web-based network service using the SRS. The data corresponding to the structural motifs includes; sequence, position in polypeptide chain, geometry, type, unique code, keywords and resolution of crystal structure. This data is available for a representative data set of 1028 protein chains and also for all 10 213 proteins in the Protein Data Bank. The three-dimensional coordinates for all structural motifs (except sheet and disulphide bridge) are also available for the representative data set. Using features in SRS, DSMP can be queried to extract information from one or more structural motifs that may be useful for sequence-structure analysis, prediction, modelling or design. AVAILABILITY: http://www. cdfd.org.in/dsmp.html

Primary pachydermoperiostosis: a case report.

Pachydermoperiostosis (PDP), a rare genodermatosis, occurred in a 38-year-old Indian male. He presented with progressive thickening of the skin on the face and scalp of 15 years duration. Widening of his wrists and ankles and broadening of the fingers and toes had also developed since then. He was born of a consanguineous marriage and had no family history of a similar disorder. He had the typical findings of complete form of PDP including cutis verticis gyrata, coarse facial features, clubbing of the digits in the skin, and periostosis and cortical thickening at the distal ends of long bones of the extremities and small bones of the hands and feet. PDP has two different forms--primary and secondary. These two entities are differentiated by family history and presence or absence of a primary lesion, usually in the lungs. Clinically, in secondary PDP, the cutaneous findings (pachydermia, seborrhoea, oiliness) are less severe than primary PDP; osteoarthropathy is more severe and painful in secondary PDP, especially with congenital heart disease. The present case was suffering from primary PDP that had expressed itself in its complete form.