345 research outputs found
Digital Phase Noise Compensation for DSCM-Based Superchannel Transmission System With Quantum Dot Passive Mode-Locked Laser
We propose a simplified digital phase noise compensation technique for a Nyquist pulse-shaped digital subcarrier multiplexed (DSCM) coherent optical transmission system, employing an optical frequency comb based on Quantum dot passive mode-locked laser (QD-PMLL). Our results show that the impact of dominant common mode phase noise can be efficiently compensated at the receiver by digitally mixing the data sideband with the complex conjugate of the residual carrier component. This digital mixing technique resulted in better bit error rate performance compared to the conventional mth power Viterbi-Viterbi algorithm for QPSK and blind phase noise compensation for 16-quadratic-amplitude modulation formats, especially in the presence of large phase noise. To this end, exploiting the mutual coherence between the mode-locked comb lines of QD-PMLL, we numerically demonstrate its potential applicability as a transmission source for coherent optical superchannel transmission
Circumventing Concept Erasure Methods For Text-to-Image Generative Models
Text-to-image generative models can produce photo-realistic images for an
extremely broad range of concepts, and their usage has proliferated widely
among the general public. On the flip side, these models have numerous
drawbacks, including their potential to generate images featuring sexually
explicit content, mirror artistic styles without permission, or even
hallucinate (or deepfake) the likenesses of celebrities. Consequently, various
methods have been proposed in order to "erase" sensitive concepts from
text-to-image models. In this work, we examine five recently proposed concept
erasure methods, and show that targeted concepts are not fully excised from any
of these methods. Specifically, we leverage the existence of special learned
word embeddings that can retrieve "erased" concepts from the sanitized models
with no alterations to their weights. Our results highlight the brittleness of
post hoc concept erasure methods, and call into question their use in the
algorithmic toolkit for AI safety
NDM-1 imported from India – first reported case in South Africa
Carbapenem-resistant Enterobacteriaceae have been increasingly reported throughout the world. The first South African report of a New Delhi metallo-beta-lactamase was from Gauteng in August 2011. Despite maintaining a high degree of vigilance, the first such case was seen in KwaZulu-Natal almost a year later. Other cases have been unable to confirm a definite link to any other affected areas; this is the first case in South Africa showing this direct epidemiological link
Surveillance and comparison of antimicrobial susceptibility patterns of ESKAPE organisms isolated from patients with bacteraemia in South Africa, 2016 - 2017
Background. In South Africa (SA), the National Department of Health has developed an Antimicrobial Resistance National Strategy Framework document to manage antimicrobial resistance (AMR). One of the strategic objectives is to optimise surveillance and early detection of AMR. At the National Institute for Communicable Diseases (NICD), an analysis of selected organisms and antimicrobial agents from both the public and the private sectors was conducted.Objectives. The relevance of surveillance for AMR is increasingly recognised in the light of global action plans to combat resistance. In this report, we present an overview of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.) organisms and Escherichia coli reported from public and private sector laboratories in SA for the period 2016 - 2017.Methods. Antimicrobial susceptibility testing (AST) profiles on selected ESKAPE organisms and E. coli isolated from blood cultures from the public and private sectors in 2016 and 2017 were analysed. AST data were extracted from a web-based electronic platform created by the NICD. Drug-bug combinations following the World Health Organization’s Global Antimicrobial Surveillance System guidelines were included in the analysis.Results. A total of 28 920 ESKAPE organisms and E. coli were reported in 2016 and 32 293 in 2017 across the two health sectors. Proportions of some organisms differed between the two health sectors, such as E. coli (19% in the public sector and 36% in the private sector), A. baumannii (14% public and 4% private), P. aeruginosa (7% public and 11% private) and S. aureus (27% public and 17% private). Susceptibility data indicated changing patterns in both sectors towards an increase in non-susceptibility to carbapenems in K. pneumoniae (p<0.01). However, we demonstrated an increase in susceptibility to cloxacillin in S. aureus (p<0.01) in both sectors.Conclusions. The key clinically important finding is the rapidly decreasing carbapenem susceptibility among Enterobacteriaceae reported in SA, irrespective of sector. In addition, the analysis provides information that could be used to monitor the effectiveness of interventions implemented at a national level under the guidance and direction of the national AMR framework.
The side effect profile of Clozapine in real world data of three large mental health hospitals
Objective:
Mining the data contained within Electronic Health Records (EHRs) can potentially generate
a greater understanding of medication effects in the real world, complementing what we
know from Randomised control trials (RCTs). We Propose a text mining approach to detect
adverse events and medication episodes from the clinical text to enhance our understanding
of adverse effects related to Clozapine, the most effective antipsychotic drug for the management of treatment-resistant schizophrenia, but underutilised due to concerns over its
side effects.
Material and methods:
We used data from de-identified EHRs of three mental health trusts in the UK (>50 million
documents, over 500,000 patients, 2835 of which were prescribed Clozapine). We explored
the prevalence of 33 adverse effects by age, gender, ethnicity, smoking status and admission type three months before and after the patients started Clozapine treatment. Where
possible, we compared the prevalence of adverse effects with those reported in the Side
Effects Resource (SIDER).
Results:
Sedation, fatigue, agitation, dizziness, hypersalivation, weight gain, tachycardia, headache,
constipation and confusion were amongst the highest recorded Clozapine adverse effect in
the three months following the start of treatment. Higher percentages of all adverse effects
were found in the first month of Clozapine therapy. Using a significance level of (p< 0.05)
our chi-square tests show a significant association between most of the ADRs and smoking
status and hospital admission, and some in gender, ethnicity and age groups in all trusts
hospitals. Later we combined the data from the three trusts hospitals to estimate the average effect of ADRs in each monthly interval. In gender and ethnicity, the results show significant association in 7 out of 33 ADRs, smoking status shows significant association in 21 out
of 33 ADRs and hospital admission shows the significant association in 30 out of 33 ADRs.
Conclusion:
A better understanding of how drugs work in the real world can complement clinical trials
High yield synthesis of electrolyte heating assisted electrochemically exfoliated graphene for electromagnetic interference shielding applications
Herein, we demonstrate a facile one pot synthesis of graphene nanosheets by electrochemical exfoliation of graphite. In the present study, we report a significant increase in the yield of graphene by electrolyte heating assisted electrochemical exfoliation method. The obtained results of heating assisted electrochemically exfoliated graphene (utilizing H2SO4 + KOH + DW) synthesis clearly exhibit that the yield increases similar to 4.5 times i.e. from similar to 17% (room temperature) to similar to 77% (at 80 degrees C). A plausible mechanism for the enhanced yield based on lattice expansion and vibration of intercalated ions has been put forward and discussed in details. The quality of graphene was examined by Raman, XPS, FTIR, AFM, SEM, TEM/HRTEM and TGA techniques. The Raman as well as morphogenesis results confirm the quality of the graphene nanosheets. We have used this graphene as electromagnetic interference shielding material where a comparatively large quantity of graphene is required. This graphene exhibits enhanced shielding effectiveness (46 dB at 1 mm thickness of stacked graphene sheets in frequency region 12.4 to 18 GHz) as compared to conventional electromagnetic interference shielding materials, which is greater than the recommended limit (similar to 30 dB) for techno-commercial applications. Thus the present work is suggestive for future studies on enhancement of yield of high quality graphene by proposed method and the use of synthesized graphene in electromagnetic interference shielding and other possible applications
Puf6 primes 60S pre-ribosome nuclear export at low temperature
Productive ribosomal RNA (rRNA) compaction during ribosome assembly necessitates establishing correct tertiary contacts between distant secondary structure elements. Here, we quantify the response of the yeast proteome to low temperature (LT), a condition where aberrant mis-paired RNA folding intermediates accumulate. We show that, at LT, yeast cells globally boost production of their ribosome assembly machinery. We find that the LT-induced assembly factor, Puf6, binds to the nascent catalytic RNA-rich subunit interface within the 60S pre-ribosome, at a site that eventually loads the nuclear export apparatus. Ensemble Förster resonance energy transfer studies show that Puf6 mimics the role of Mg2+ to usher a unique long-range tertiary contact to compact rRNA. At LT, puf6 mutants accumulate 60S pre-ribosomes in the nucleus, thus unveiling Puf6-mediated rRNA compaction as a critical temperature-regulated rescue mechanism that counters rRNA misfolding to prime export competence.ISSN:2041-172
RNA Sequencing of Primary Cutaneous and Breast-Implant Associated Anaplastic Large Cell Lymphomas Reveals Infrequent Fusion Transcripts and Upregulation of PI3K/AKT Signaling via Neurotrophin Pathway Genes
Cutaneous and breast implant-associated anaplastic large-cell lymphomas (cALCLs and BI-ALCLs) are two localized forms of peripheral T-cell lymphomas (PTCLs) that are recognized as distinct entities within the family of ALCL. JAK-STAT signaling is a common feature of all ALCL subtypes, whereas DUSP22/IRF4, TP63 and TYK gene rearrangements have been reported in a proportion of ALK-negative sALCLs and cALCLs. Both cALCLs and BI-ALCLs differ in their gene expression profiles compared to PTCLs; however, a direct comparison of the genomic alterations and transcriptomes of these two entities is lacking. By performing RNA sequencing of 1385 genes (TruSight RNA Pan-Cancer, Illumina) in 12 cALCLs, 10 BI-ALCLs and two anaplastic lymphoma kinase (ALK)-positive sALCLs, we identified the previously reported TYK2-NPM1 fusion in 1 cALCL (1/12, 8%), and four new intrachromosomal gene fusions in 2 BI-ALCLs (2/10, 20%) involving genes on chromosome 1 (EPS15-GNG12 and ARNT-GOLPH3L) and on chromosome 17 (MYO18A-GIT1 and NF1-GOSR1). One of the two BI-ALCL samples showed a complex karyotype, raising the possibility that genomic instability may be responsible for intra-chromosomal fusions in BI-ALCL. Moreover, transcriptional analysis revealed similar upregulation of the PI3K/Akt pathway, associated with enrichment in the expression of neurotrophin signaling genes, which was more conspicuous in BI-ALCL, as well as differences, i.e., over-expression of genes involved in the RNA polymerase II transcription program in BI-ALCL and of the RNA splicing/processing program in cALCL
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