On Precoding for Constant K-User MIMO Gaussian Interference Channel with Finite Constellation Inputs

This paper considers linear precoding for constant channel-coefficient $K$-User MIMO Gaussian Interference Channel (MIMO GIC) where each transmitter-$i$ (Tx-$i$), requires to send $d_i$ independent complex symbols per channel use that take values from fixed finite constellations with uniform distribution, to receiver-$i$ (Rx-$i$) for $i=1,2,\cdots,K$. We define the maximum rate achieved by Tx-$i$ using any linear precoder, when the interference channel-coefficients are zero, as the signal to noise ratio (SNR) tends to infinity to be the Constellation Constrained Saturation Capacity (CCSC) for Tx-$i$. We derive a high SNR approximation for the rate achieved by Tx-$i$ when interference is treated as noise and this rate is given by the mutual information between Tx-$i$ and Rx-$i$, denoted as $I[X_i;Y_i]$. A set of necessary and sufficient conditions on the precoders under which $I[X_i;Y_i]$ tends to CCSC for Tx-$i$ is derived. Interestingly, the precoders designed for interference alignment (IA) satisfy these necessary and sufficient conditions. Further, we propose gradient-ascent based algorithms to optimize the sum-rate achieved by precoding with finite constellation inputs and treating interference as noise. Simulation study using the proposed algorithms for a 3-user MIMO GIC with two antennas at each node with $d_i=1$ for all $i$, and with BPSK and QPSK inputs, show more than 0.1 bits/sec/Hz gain in the ergodic sum-rate over that yielded by precoders obtained from some known IA algorithms, at moderate SNRs.Comment: 15 pages, 9 figure

Is adding intra-articular steroid in total knee arthroplasty cocktail obligatory?

Background: The patients can undergo total knee replacement surgery either under general anaesthesia, combined spinal and epidural anaesthesia, nerve root block, spinal combined with intra-articular knee cocktail. There is an ongoing debate amongst Arthroplasty surgeons whether to include steroid in the cocktail or not. The aim of this study is to assess whether there is an added benefit of including steroid in the intraarticular mixture.Methods: This prospective study was conducted at Sri Ramachandra Institute of Higher education, Chennai between December 2017 to December 2018. The study was conducted in the Arthroplasty unit, Department of Orthopaedics. SRIHER ethics committee clearance was obtained prior to the start of the study. The inclusion criteria were patients who underwent total knee replacement surgery under combined spinal and intra-articular knee cocktail. Patients were divided into two groups based on the use of steroid in the intra-articular mixture. Patients were evaluated using Visual analogue scale, opioids usage as primary endpoint while any joint infection within six months of the surgery and knee society score at 1 month and 6 months as the secondary endpoint.Results: The mean visual analogue score for the 0 pod for the group I and group II were 2.3 and 2.4 respectively. There was no case of infection in both groups.Conclusions: There is no fringe benefit of adding steroid to the knee cocktail. So it is not obligatory to add steroid in intra-articular total knee arthroplasty cocktail

Analysis of SNRB in patients with lumbar radiculopathy resistant to conservative treatment

Background:The transforaminal application performed with SNRB (Selective nerve root blocks) should be more accurate. Moreover, the amount of corticosteroid and local anesthetic can be reduced compared to the amount of these agents administered with the epidural steroid.Methods:Prospective study of 72 patients with low back pain done in Sri Ramachandra medical centre, Chennai during April 2012 to April 2014. 46 patients were diagnosed to have inter vertebral disc and 26 patients with Lumbar canal stenosis. The patients were evaluated using VAS score and Oswestry disability index. The indication and determination of the therapeutic SNRB level was established by the spine surgeon after all the diagnostic test results had been obtained and after a detailed discussion with the patient. After confirming the correct placement of spinal needle with a short bevel with the help of contrast, a solution of 1ml of 0.5% sensorcaine with 1 ml of triamcinolone acetonide (Inj. kenocort) is injected.Results:Only 2 patients out of 72 had persistent pain and underwent surgery. 60 of our patients were comfortable and were able to proceed with their normal life/day to day activities following the administration of one block.Conclusion:Selective nerve root block is effective and less invasive intervention, and serves as an adjunct to non-operative treatment. The blocks give the best result in disc herniation cases, followed by favorable results in foraminal stenosis.

Osteofibrous dysplasia of the proximal tibia: an illustrative case report

A 5 years old girl presented 3 years back with pain and swelling over the upper right leg for 2 years duration. X-ray, CT and MRI revealed osteolytic well defined lesion 2.5 × 2 cm in the meta-diaphyseal region of the proximal tibia with pathological fracture of anterolateral cortex. Child underwent thorough curettage of the lesion and the defect was filled with allograft (iliac crest graft) from mother which was harvested in an adjacent operation theatre. The limb was protected with a plaster splint for a period of 3 months. The graft gradually consolidated and new bone formation was apparent by 6 months. Remodelling of the medullary canal occurred at 1 year follow up. Child has been followed up to 3 years (till date) and there is no evidence of recurrence. The case illustrates that osteofibrous dyplasia can be effectively treated by curettage and replacement of defect by allograft from parents.

Functional and radiological analysis of posterior lumbar interbody fusion in spondylolisthesis

Background:Spondylolisthesis is present in 5% of the adult population with clinical evidence of low back pain. These patients are treated initially by conservative measures, failing of which surgical intervention is mandatory. Majority of patients with varying degree of slip and disability ultimately require surgical intervention. In this study we are trying to analyse the functional outcome following posterior lumbar interbody fusion in spondylolisthesis.Methods: Posterior lumbar interbody fusion using pedicle screw and rods with cage was performed on 25 patients. 6 months follow-up was completed in 25 patients who were then reviewed at regular intervals. Out of the 25 patients, 17(68%) were females and 8(32%) were males. The mean age of the patients was 40.64 years. Out of 25 patients, 14 patients had listhesis at L4 – L5 level and another 11 at L5 – S1 level. 21(84%) were Isthmic variant and 4 (16%) were Degenerative spondylolisthesis.Results:The mean follow up period in this study of 25 patients is 19 months. Out of 25 patients, there was mean improvement of 18.96 in the Oswestry scoring index. The Visual analogue scale score showed a mean improvement of 6.48. Radiologically, the percentage of slip was decreased by a mean of 8.40%. One patient had a cage extrusion with no neurological deficit.Conclusions:The pedicle screw with rod and cage system is easy to use and provides the anatomic restoration of the isthmus in isthmic spondylolisthesis or restoring the stability after laminectomy/discectomy in degenerative spondylolisthesis. From our study, we strongly believe that this technique is very useful in low grade degenerative and isthmic spondylolisthesis

Management of infected custom mega prosthesis by Ilizarov method

A 26 year old male patient with an aggressive giant cell tumour of the left distal femur was managed by wide excision and insertion of custom mega prosthesis. Patient developed deep infection which did not subside with multiple debridements and antibiotics.  Hence the custom mega prosthesis was removed and the bone gap was managed by Ilizarov method.  Ilizarov fixation of the left femur and tibia was done.  Femoral and tibial corticotomy was done and the bone segments were transported towards the knee to finally achieve a knee arthrodesis.  The case illustrates the method and difficulties encountered during the treatment

pengaruh serbuk gergaji kayu jati terhadap kekuatan mekanis komposit partikel

Limbah serbuk gergaji hasil proses penggergajian kayu log maupun papan, sangatlah melimpah dan belum termanfaatkan secara maksimal, penelitian ini bertujuan untuk mengetahui pengaruh perbandingan fraksi volume serbuk gergaji kayu jati terhadap kekuatan mekanis komposit partikel. Resin yang digunakan dalam penelitian ini adalah Poliester tak jenuh BQTN 157 dan serbuk gergaji yang digunakan adalah limbah penggergajian kayu jati, perbandingan fraksi volume yang digunakan adalah 90%:10%, 80%:20%, 70%:30%, 60%:40%, ukuran serbuk gergaji kayu jati adalah ± 0,84mm – 1mm. Proses pengeringan serbuk gergaji dengan suhu 90 ºC selama 1 jam. Campuran resin katalis dan serbuk gergaji kayu jati sesuai dengan perhitungan fraksi volume yang telah ditentukan. Proses pencetakan menggunakan metode hand lay-up dan diberikan tekanan sebesar 1 MPa lama waktu penekanan 15 menit, proses pengeringan komposit selama 24 jam, komposit dilakukan proses post curring dengan suhu 62ºC waktu penahanan 4 jam. Dimensi spesimen uji tarik mengikuti standar ASTM D 638 dan spesimen uji bending mengikuti standar ASTM D 790. Hasil penelitian kekuatan tarik dan kekuatan bending tertinggi didapatkan pada perbandingan fraksi volume 90% : 10% yaitu 17,14 MPa dan 27,62 MPa, semakin bertambahnya serbuk kayu mengakibatkan kekuatan tarik dan bending menurun, untuk perbandingan fraksi volume 60% : 40 % masih masuk kedalam standar SNI 03-215-2006 dan SNI 03-2015-1996 untuk pengujian bending dan pengujian tarik. Semakin bertambah serbuk gergaji mengakibatkan nilai densitas semakin menurun

Live Cell Imaging Unveils Multiple Domain Requirements for In Vivo Dimerization of the Glucocorticoid Receptor

Glucocorticoids are essential for life, but are also implicated in disease pathogenesis and may produce unwanted effects when given in high doses. Glucocorticoid receptor (GR) transcriptional activity and clinical outcome have been linked to its oligomerization state. Although a point mutation within the GR DNA-binding domain (GRdim mutant) has been reported as crucial for receptor dimerization and DNA binding, this assumption has recently been challenged. Here we have analyzed the GR oligomerization state in vivo using the number and brightness assay. Our results suggest a complete, reversible, and DNA-independent ligand-induced model for GR dimerization. We demonstrate that the GRdim forms dimers in vivo whereas adding another mutation in the ligand-binding domain (I634A) severely compromises homodimer formation. Contrary to dogma, no correlation between the GR monomeric/dimeric state and transcriptional activity was observed. Finally, the state of dimerization affected DNA binding only to a subset of GR binding sites. These results have major implications on future searches for therapeutic glucocorticoids with reduced side effects.Fil: Presman, Diego Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Ogara, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Stortz, Martin Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Alvarez, Lautaro Damian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; ArgentinaFil: Pooley, John R.. National Cancer Institute. Laboratory of Receptor Biology and Gene Expression; Estados Unidos. University of Bristol; Reino UnidoFil: Schiltz, R. Louis. National Cancer Institute. Laboratory of Receptor Biology and Gene Expression; Estados UnidosFil: Grøntved, Lars. National Cancer Institute. Laboratory of Receptor Biology and Gene Expression; Estados UnidosFil: Johnson, Thomas A.. National Cancer Institute. Laboratory of Receptor Biology and Gene Expression; Estados UnidosFil: Mittelstadt, Paul R.. National Cancer Institute. Laboratory of Immune Cell Biology; Estados UnidosFil: Ashwell, Jonathan D.. National Cancer Institute. Laboratory of Immune Cell Biology; Estados UnidosFil: Ganesan, Sundar. National Cancer Institute. Laboratory of Receptor Biology and Gene Expression; Estados Unidos. National Institute of Allergy and Infectious Diseases; Estados UnidosFil: Burton, Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; ArgentinaFil: Levi, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Hager, Gordon L.. National Cancer Institute. Laboratory of Receptor Biology and Gene Expression; Estados UnidosFil: Pecci, Adali. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentin