Cortical Maps: Where Theory Meets Experiments

Primary visual cortex (V1) has remarkably systematic functional maps. One commonly used class of computational models proposes that such maps are generated by a mechanism that projects the multiple dimensions of neuronal responses smoothly onto the two dimensions of cortex. In this issue of Neuron, Mriganka Sur and colleagues find a close match between such model predictions and measurements from ferret V1

Lower pole of patella fractures treated with non-absorbable trans-osseous sutures: an effective surgical method to avoid implant related complications

Background: The treatment option for inferior pole of patella fracture is still being debated. Although tension‑band wiring is the most widely used technique to treat patellar fractures, metal implant‑related complications such as implant failure, palpable hardware are very common and additional procedures are often necessary to treat the complications. The aim of the study was to evaluate the functional results in patients with inferior pole of patella fracture treated by trans-osseous non-absorbable suture fixation.Methods: Patients who underwent trans-osseous suture fixation by no. 5 Ethibond for post-traumatic distal pole patella fracture were included in the study. This was a prospective study conducted at a tertiary care Government Hospital in Kolkata, between December 2018 to May 2020. All patients were followed up at an interval of 2 weeks, 6 weeks, 12 weeks, 6 months and 9 months. Bostman score was used to assess the functional outcomes of the patients.Results: Outcome at final follow-up was assessed with Bostman scoring system. In a total of 11 patients, 8 (72.8%) patients showed excellent and 3 (27.2%) patients had good results during the final follow-up. None of the patients demonstrated unsatisfactory result. At the end of 9 months, the average Bostman score for 11 patients was 27.9.Conclusions: The trans-osseous suturing with non-absorbable sutures is a safe and effective fixation technique for the treatment of distal pole patella fractures. It allows for rapid recovery with minimal implant‑related complications. It also reduces the re-surgery rates significantly

Surgical fixation of posterior cruciate ligament avulsion fracture from tibial attachment using cannulated cancellous screw: a clinical, radiological and functional outcome evaluation

Background: PCL (posterior cruciate ligament) is the main posterior stabilizer of the knee and plays a role in central axis controlling and imparting rotational stability to the knee. Injury to PCL presents commonly with avulsion fractures from its tibial attachment. An avulsion fracture of the PCL, if not surgically fixed, may lead to secondary changes in the knee joint. The aim of the study was to evaluate the clinical and functional results in patients with PCL tibial avulsion fractures treated by CC (cannulated cancellous) screw fixation.Methods: This was a prospective study conducted at a tertiary care government hospital in Kolkata, between December 2018 to July 2020 on patients who underwent CC screw fixation for post-traumatic PCL avulsion fracture from tibial site. All patients were followed up for 9 months. Lysholm knee score was used to assess the functional outcomes of the patients.Results: In a total of 10 patients, 9 (90%) patients showed excellent and 1 (10%) patient had good result during the final follow-up. 80% patients did not develop any complications. At the end of 9 months, the mean Lysholm score was 95.6. 8 (80%) patients achieved almost full knee ROM post-operatively by the end of final follow-up.Conclusions: Surgical fixation using CC screws is a simple, easy, safe and reproducible method without requiring significant expertise for achieving good stability in PCL tibial site avulsion fractures, where early intervention prevents significant late disability as it provides an excellent clinical, functional and radiographic outcome along with good joint function.

Spatial Relationship between Flavoprotein Fluorescence and the Hemodynamic Response in the Primary Visual Cortex of Alert Macaque Monkeys

Flavoprotein fluorescence imaging (FFI) is a novel intrinsic optical signal that is steadily gaining ground as a valuable imaging tool in neuroscience research due to its closer relationship with local metabolism relative to the more commonly used hemodynamic signals. We have developed a technique for FFI imaging in the primary visual cortex (V1) of alert monkeys. Due to the nature of neurovascular coupling, hemodynamic signals are known to spread beyond the locus of metabolic activity. To determine whether FFI signals could provide a more focal measure of cortical activity in alert animals, we compared FFI and hemodynamic point spreads (i.e. responses to a minimal visual stimulus) and functional mapping signals over V1 in macaques performing simple fixation tasks. FFI responses were biphasic, with an early and focal fluorescence increase followed by a delayed and spatially broader fluorescence decrease. As expected, the early fluorescence increase, indicating increased local oxidative metabolism, was somewhat narrower than the simultaneously observed hemodynamic response. However, the later FFI decrease was broader than the hemodynamic response and started prior to the cessation of visual stimulation suggesting different mechanisms underlying the two phases of the fluorescence signal. FFI mapping signals were free of vascular artifacts and comparable in amplitude to hemodynamic mapping signals. These results indicate that the FFI response may be a more local and direct indicator of cortical metabolism than the hemodynamic response in alert animals

Spark Plasma Sintering of Magnesium Matrix Composites

Magnesium (Mg) is widely used as a structural material due to its low density (1.74 g/cm3), high specific strength and good machinability. Due to these intrinsic properties, magnesium is being used in aerospace and automobile industries as a replacement of steel and aluminum. Moreover, it is also used as a replacement of plastics in electronics and computer industries. However, Mg shows poor wear resistance. In this thesis, efforts are directed towards synthesizing high strength magnesium matrix composites having excellent wear resistance. In this work, graphene platelets (GPL) and nano SiC reinforced Mg matrix composites were synthesized using spark plasma sintering (SPS) technique. SPS is a novel nanoprocessing method where uniaxial pressure and pulse direct current are applied simultaneously to consolidate powders. Mg-GPL matrix composites exhibited improved hardness and ductility. In Mg-nano SiC composites, significant improvement of hardness and ultimate compressive strength was observed. GPL and nano-SiC particles also resulted in substantial improvement in tribological properties due to the lubrication effect of GPL and the defensive mechanism by hard nano-SiC particles.School of Materials Science & Engineerin

Colonization behaviour of arbuscular mycorrhizal fungi and phosphorus uptake pattern of mycorrhizal sensitive upland paddy using hydroponics culture

Three upland rice cultivars namely Vandana, Brown Gora and Kalinga collected from the Central Rainfed Upland Rice Research Station (CRURRS), Hazaribag, Jharkhand of the Central Rice Research Institute, are mycorrhiza sensitive genotypes. Their affinity towards mycorrhizal colonization varied. The cv. Kalinga had the highest colonization followed by Vandana and Brown Gora. Variation of arbuscular mycorrhizal fungi affinity of the rice genotypes might be due to the variable demands of phosphorus nutrition of the different genotypes. To justify these variable demands of phosphorus among these three cultivars of rice, four different doses of phosphorus (5, 10, 15 and 20 ppm) were imposed to them in a system of hydroponics. Overall, among the three cultivars, the highest uptake efficiency (34% at 30 days, 57% at 45 days, 68% at 60days and 70% at 75 days interval) throughout the growth period was noticed in the cv. Brown Gora, followed by Kalinga and Vandana. The physiological demands of phosphorus of these cultivars were finally estimated as the contribution of uptake phosphorus to the total dry matter production of the plants with respect to available phosphorus. The overall results of these estimations gave the highest value in cv. Kalinga followed by the cv. Vandana and Brown Gora. Therefore, the cultivars Brown Gora and Kalinga could be recommended for the cultivation of the vast upland rain-fed areas of the country for higher yield and increased phosphorus use efficiency which could ultimately contribute significantly to the food grain production of the country

LAPSES: A Recipe for High-Performance Adaptive Router Design

Earlier research has shown that adaptive routing can help in improving network performance. However, it has not received adequate attention in commercial routers mainly due to the additional hardware complexity, and the perceived cost and performance degradation that may result from this complexity. These concerns can be mitigated if one can design a cost-effective router that can support adaptive routing. This paper proposes a three step recipe — Look-Ahead routing, intelligent Path Selection, and an Economic Storage implementation, called the LAPSES approach — for cost-effective high performance pipelined adaptive router design. The first step, look-ahead routing, reduces a pipeline stage in the router by making table lookup and arbitration concurrent. Next, three new traffic-sensitive path selection heuristics (LRU, LFU and MAX-CREDIT) are proposed to select one of the available alternate paths. Finally, two techniques for reducing routing table size of the adaptive router are presented. These are called meta-table routing and economical storage. The proposed economical storage needs a routing table with only 9 and 27 entries for two and three dimensional meshes, respectively. All these design ideas are evaluated on a (16 16) mesh network via simulation. A fully adaptive algorithm and various traffic patterns are used to examine the performance benefits. Performance results show that the look-ahead design as well as the path selection heuristics boost network performance, while the economical storage approach turns out to be an ideal choice in comparison to full-table and meta-table options. We believe the router resulting from these three design enhancements can make adaptive routing a viable choice for interconnects.

Studies on Multifunctional Effect of All-Trans Retinoic Acid (ATRA) on Matrix Metalloproteinase-2 (MMP-2) and Its Regulatory Molecules in Human Breast Cancer Cells (MCF-7)

Background. Vitamin A derivative all-trans retinoic acid (ATRA) is considered as a potent chemotherapeutic drug for its capability of regulating cell growth and differentiation. We studied the effect of ATRA on MMP-2 in MCF-7, human breast cancer cells, and the probable signaling pathways which are affected by ATRA on regulating pro-MMP-2 activity and expression. Methods. Gelatin zymography, RT-PCR, ELISA, Western blot, Immunoprecipitation, and Cell adhesion assay are used. Results. Gelatin zymography showed that ATRA caused a dose-dependent inhibition of pro-MMP-2 activity. ATRA treatment downregulates the expression of MT1-MMP, EMMPRIN, FAK, NF-kB, and p-ERK. However, expression of E-cadherin, RAR, and CRABP increased upon ATRA treatment. Binding of cells to extra cellular matrix (ECM) protein fibronectin reduced significantly after ATRA treatment. Conclusions. The experimental findings clearly showed the inhibition of MMP-2 activity upon ATRA treatment. This inhibitory effect of ATRA on MMP-2 activity in human breast cancer cells (MCF-7) may result due to its inhibitory effect on MT1-MMP, EMMPRIN, and upregulation of TIMP-2. This study is focused on the effect of ATRA on MMP, MMP-integrin-E-cadherin interrelationship, and also the effect of the drug on different signaling molecules which may involve in the progression of malignant tumor development

Evaluation the results of surgical management of traumatic paraplegia in traumatic thoracolumbar fractures

Background: Thoracolumbar spine fractures are common injuries that can result in significant disability, deformity and neurological deficit. Aim of this study was to evaluate the results of surgical management of traumatic paraplegia, complete or incomplete as classified by Frankel scoring.Methods: A prospective study was conducted in patients attending outdoor and emergency department of Orthopedics of a tertiary care teaching institute in Kolkata, West Bengal with traumatic paraplegia involving the dorsolumbar spine. The important objectives are the time for recovery of various functions like sensory, motor and bowel and bladder function, comparison between early and late decompression, results of posterolateral fusion and time taken for solid bony fusion after operation. Total 46 cases were selected within a minimum of 6-month post-operative follow-up of which 4 cases lost in follow-up. Data collected from patient records included age, sex, time from injury to hospitalization, initial neurological status as per Frankel Score, MRI findings, surgery performed, postoperative course and neurological status at the time of discharge and latest follow up. Patients lost to follow up were not studied for outcome analysis.Results: When decompression done within 1st week in incomplete paraplegia, 80% of the patients showed return of grade 3 power. In complete paraplegia cases, 11% of the patients had return of power up to grade 3 when decompression done within 1 week, where no cases showed return of grade 3 power when decompression done after 2nd or 3rd week.Conclusions: After recovery from spinal shock, the earlier the surgical compression done, the better the neurological and bowel/bladder function recovery both in complete and incomplete paraplegic cases. Reduction is better and easy and less time consuming in early decompression than in late. Motor recovery can continue for over 6 months after decompression